Recycled material production method

Abstract

Provided is a method with which a recycled material can be produced without going through a complicated process by using a recovered material, even when the recovered material is a plastic label to which a TAC label is adhered or even when a container is added thereto.　In this production method for producing a recycled material from a recovered material derived from a container to which a label is attached, the recovered material includes a label composite, and in the label composite, a first label having a first ink layer and a first film substrate and a second label having an adhesive layer and a second film substrate are layered so that the adhesive layer adheres to the first film substrate. The production method comprises: an ink layer removal step in which the first ink layer is removed from the label composite to obtain a substrate composite in which the second film substrate is layered on the first film substrate via the adhesive layer; and a recycled material production step in which, after the ink layer removal step, a recycled material using the substrate composite as a raw material is obtained.

Description

Manufacturing methods for recycled materials

[0001] The present invention relates to a method for producing recycled materials from recovered material originating from labelled containers.

[0002] In recent years, plastic products such as polyethylene terephthalate bottles (PET bottles) have been widely used. From the viewpoints of resource conservation and environmental considerations, there is a demand for recycling plastic products such as PET bottles. Furthermore, plastic labels (hereinafter also referred to as "plastic labels") are sometimes attached to the body of PET bottles. Plastic labels typically have an ink layer printed thereon to display product information, etc. There is a movement to reuse these plastic labels in the same way as PET bottles.

[0003] When recycling plastic labels, the plastic labels are usually cut into pieces, which are then melt-kneaded and pelletized (see, for example, Patent Document 1).

[0004] There are several types of plastic labels that have different attachment methods. Examples include shrink labels, which are attached to containers by heat shrinkage; stretch labels, which are attached to containers by self-expanding; wrap labels, which are attached by wrapping them around containers; and tack labels, which are attached to containers by using adhesives such as pressure-sensitive adhesives. In recent years, there has been a need for tack labels to be attached to other labels, such as shrink labels, stretch labels, and wrap labels. When used in this way, tack labels are highly convenient because they can be used to display different types of information than attached labels, such as the latest information and campaign information.

[0005] Japanese Patent Application Laid-Open No. 2022-68217

[0006] While the reuse of PET bottles and the plastic labels attached to the bottle bodies has been studied, the reuse of the tack labels attached to the plastic labels has not yet been considered.

[0007] The present invention aims to provide a method for producing recycled materials using collected materials without going through complicated steps, even if the collected materials are plastic labels with tack labels attached or a container added thereto.

[0008] The present invention relates to the following examples [1] to [5]. [1] A manufacturing method for producing recycled materials from recovered materials derived from labeled containers, wherein the recovered materials include a label composite, wherein the label composite is a first label having a first ink layer and a first film substrate, and a second label having a pressure-sensitive adhesive layer and a second film substrate, laminated together such that the pressure-sensitive adhesive layer is attached to the first film substrate, the manufacturing method comprising: an ink layer removing step of removing the first ink layer from the label composite to obtain a substrate composite in which the second film substrate is laminated to the first film substrate via the pressure-sensitive adhesive layer; and a recycled material manufacturing step of obtaining a recycled material using the substrate composite as a raw material after the ink layer removing step. [2] The manufacturing method according to [1], wherein the second label further has a second ink layer, and the pressure-sensitive adhesive layer, the second film substrate, and the second ink layer are laminated together in this order, and the second ink layer is removed from the label composite together with the first ink layer in the ink layer removing step. [3] The manufacturing method according to [1] or [2], wherein in the label composite, the first film substrate, the second film substrate, and the adhesive layer are all made of a polyester-based resin material. [4] The manufacturing method according to any one of [1] to [3], wherein the recovered material further includes a container, and the recycled material manufacturing step is a step of obtaining a recycled material using the substrate composite and the container as raw materials. [5] The manufacturing method according to [4], wherein the container is made of a polyethylene terephthalate-based resin material.

[0009] According to the manufacturing method of the present invention, whether the recovered material is a plastic label with a tack label attached or a container added thereto, it is possible to manufacture recycled materials using this recovered material without going through complicated processes.

[0010] Fig. 1 is a schematic cross-sectional view showing an example of the configuration of a label composite contained in recovered material of this embodiment. Fig. 2 is a schematic cross-sectional view showing an example of a substrate composite obtained from the label composite of this embodiment. Fig. 3 is a diagram showing an example of the flow of a method for producing recycled material of this embodiment.

[0011] The present invention is a method for producing recycled materials from recovered materials derived from containers with labels attached. The recovered materials include a label composite. The label composite comprises a first label having a first ink layer and a first film substrate, and a second label having a pressure-sensitive adhesive layer and a second film substrate, laminated together such that the pressure-sensitive adhesive layer is attached to the first film substrate. The production method of the present invention includes an ink layer removal step of removing the first ink layer from the label composite to obtain a substrate composite in which the second film substrate is laminated to the first film substrate via the pressure-sensitive adhesive layer, and a recycled material production step of obtaining a recycled material using the substrate composite as a raw material after the ink layer removal step.

[0012] In the method for producing recycled materials from collected materials, even if the collected materials contain label composites in which plastic labels are adhered to each other, by removing the ink layer from the label composite to obtain a substrate composite and using this as a raw material to obtain recycled materials, recycled materials can be efficiently obtained without going through the complicated process of separating the label composites and using all of the labels that make up the label composite as raw materials.

[0013] According to the present invention, the label composites in which plastic labels are adhered to each other and contained in the recycled waste include a label composite in which a first label having a first ink layer and a first film substrate and a second label having a pressure-sensitive adhesive layer and a second film substrate are laminated such that the pressure-sensitive adhesive layer is attached to the first film substrate. The method further includes an ink layer removal step in which the first ink layer of this label composite is removed to obtain a substrate composite in which the second film substrate is laminated to the first film substrate via the pressure-sensitive adhesive layer. This allows the first ink layer to be removed in a simple process without separating the label composite into the first film and the second film. This improves manufacturing efficiency. The label composite subjected to the ink layer removal step may be the same size as when it was attached to the container, or may be cut, and may be provided together with the container.

[0014] [Label Composite] Fig. 1 is a schematic cross-sectional view showing an example of the configuration of a label composite included in the collected waste of this embodiment. As shown in Fig. 1, the label composite 100 is a laminate consisting of a first label 110 and a second label 120. The first label 110 has a first film substrate 111 and an ink layer (first ink layer) 112 provided on one surface of the first film substrate 111. The second label 120 has a second film substrate 121, an ink layer (second ink layer) 122 provided on one surface of the second film substrate 121, and an adhesive layer 124 provided on the other surface of the second film substrate 121.

[0015] In the first label 110, the first film substrate 111 and the ink layer 112 are essential layers. At least a portion of the surface of the first film substrate 111 opposite the surface on which the ink layer 112 is provided is in contact with the adhesive layer 124. An ink layer 113 may be provided on the surface of the first film substrate 111 opposite the surface on which the ink layer 112 is provided, in an area not in contact with the adhesive layer 124. The first label 110 may also include layers (not shown) other than those described above. In the first label 110, the ink layers 112 and 113 are not particularly limited as long as they are removable with a treatment solution, but may have the function of protecting the label (label protection layer), the function of imparting decoration such as a matte finish (decoration layer), or the function of displaying information (information display layer). Furthermore, when product information is displayed using the ink layer 112, the ink layer 113 is preferably a label protection layer or a decoration layer.

[0016] In the second label 120, the second film substrate 121 and the adhesive layer 124 are essential layers, while the ink layer 122 is an optional layer. The second label 120 may also have other layers (not shown). The ink layer 122 decorates the second label 20 or displays additional information (such as a two-dimensional code or a URL) such as product information or campaign information.

[0017] Label composite 100 has a layer structure in which adhesive layer 124 of second label 120 is adhered to first film substrate 111 of first label 110. In label composite 100, the size of second label 120 is not limited, but it is often used to display additional information, and is preferably smaller than the size of first label 110.

[0018] The first label 110 is not limited to a plastic label having a first film substrate 111 and an ink layer 112. Plastic labels include shrink labels, wrap labels, stretch labels, and tack labels, depending on the attachment method. Shrink labels are attached to containers by heat shrinking. Wrap labels are attached by wrapping them around the container and gluing or fusing the label edges. Stretch labels are attached to containers by self-expanding. Tack labels are attached to containers by using an adhesive such as a pressure-sensitive adhesive. The first label 110 is, for example, a shrink label, wrap label, or stretch label. The second label 120 is a plastic label having an adhesive layer 124 on its outermost surface, preferably a tack label. If the first label 110 is a wrap label having an adhesive layer for attachment to a container, the adhesive layer is preferably removable by dissolving or swelling in a treatment solution. An adhesive layer that cannot be removed by the treatment solution may be provided. In this case, it is preferable that an ink layer that can be dissolved or swelled by the treatment solution and removed is provided between the adhesive layer and the first film substrate 111, and that the adhesive layer can be removed by removing the ink layer.

[0019] <Ink Layer> The ink layers 112, 113, and 122 may be formed using any of water-based ink, oil-based ink (solvent-based ink), and UV-curable ink. Conventional inks can be used as the water-based ink, oil-based ink, and UV-curable ink that form the ink layers. For example, oil-based inks may be inks containing additives in addition to a colorant such as a pigment or dye, a binder resin, and an organic solvent. For water-based inks, inks containing water and a colorant in addition to a water-soluble or water-dispersible binder resin and additives may be used. For UV-curable inks, inks containing additives such as a colorant, UV-curable monomer, UV-curable oligomer, resin, and photopolymerization initiator may be used. UV-curable inks are typically solvent-free inks. Additives include lubricants, anti-blocking agents, matting agents, and anti-settling agents.

[0020] The ink layer can be formed on the surface of the first film substrate 111 or the second film substrate 112 by, for example, gravure printing, flexographic printing, screen printing, liquid toner printing, inkjet printing, or the like. The ink layer may be a single layer or multiple layers. The thickness of the ink layer can be selected appropriately depending on the application, etc., and can be, for example, approximately 0.1 μm or more and 10 μm or less. Depending on its function, the ink layer may be a design printing layer, a base printing layer, a surface coating layer, etc., and these are provided as a single layer or in appropriate combination, and the area in which each layer is provided is also selected appropriately. The area in which the ink layer is formed is selected appropriately depending on its purpose.

[0021] The ink layer 112 is an ink layer that can be removed by dissolving or swelling in a processing solution. It is also preferable that the ink layers 113 and 122 are also ink layers that can be removed by dissolving or swelling in a processing solution. When the ink layers 112, 113, and 122 are multilayered, it is preferable that the layer in contact with the film substrate is an ink layer or anchor layer that can be removed by dissolving or swelling in a processing solution. In this case, the entire ink layer can be removed from the film substrate by removing the anchor layer in contact with the film substrate. From the viewpoint of ease of removal, it is preferable that the anchor layer is formed of either a water-based ink or an oil-based ink. When the ink layers 112, 113, and 122 are multilayered, all of the layers may be removable with a processing solution.

[0022] <Film Substrate> The first film substrate 111 of the first label 110 and the second film substrate 121 of the second label 120 are synthetic resin films. The synthetic resin constituting the synthetic resin film is not particularly limited, and examples include thermoplastic resins selected from polystyrene-based (PS-based) resins such as general-purpose polystyrene and styrene-butadiene block copolymers; polyester-based resins such as polyethylene terephthalate (PET-based) resins and polylactic acid-based resins; polyolefin-based resins such as polyethylene-based resins, polypropylene-based resins and cyclic olefin-based resins; polycarbonate-based resins; polyvinyl chloride-based resins; and polyamide-based resins, and the like, either alone or in combination.

[0023] Examples of polyester resins include polyethylene terephthalate (PET) resins, poly(ethylene-2,6-naphthalenedicarboxylate) (PEN), polylactic acid (PLA), etc. Among these, PET resins are preferred. Examples of the PET resin include PET using terephthalic acid as the dicarboxylic acid component and ethylene glycol as the diol component; a copolymer polyester (CHDM copolymer PET) using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the main diol component, and 1,4-cyclohexanedimethanol (CHDM) as the copolymer component; a copolymer polyester (NPG copolymer PET) using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the main diol component, and neopentyl glycol (NPG) as the copolymer component; diol-modified PET such as a copolymer polyester using terephthalic acid as the dicarboxylic acid component, ethylene glycol as the main diol component, and diethylene glycol as the copolymer component; and dicarboxylic acid-modified PET such as a copolymer polyester using terephthalic acid as the main dicarboxylic acid component, isophthalic acid and / or adipic acid as the copolymer component, and ethylene glycol as the diol component.

[0024] The synthetic resin film may be a single-layer film or a laminated film of two or more layers. The synthetic resin film may be a non-stretched film or a stretched film, but typically, in the case of shrink labels, uniaxially stretched films or biaxially stretched films that are stretched mainly in the shrinkage direction are used, in the case of tack labels and wrap-around labels, non-stretched films or non-heat-shrinkable biaxially stretched films are used, and in the case of stretch labels, non-stretched films or uniaxially stretched films or biaxially stretched films stretched by 2 times or less are used.

[0025] The synthetic resin film may be a film that is substantially neither heat-shrinkable nor self-stretchable, or may be a film that is heat-shrinkable and / or self-stretchable. Heat-shrinkable refers to the property of shrinking at least in the main stretching direction when heated to a heat-shrinkage temperature (e.g., 70°C to 100°C). Self-stretchable refers to the property of stretching when a tensile force is applied in one direction and returning to approximately its original length when the tensile force is released. The synthetic resin film used as the film substrate for wrap-around labels and tack labels is preferably a film that is substantially heat-shrinkable, and more preferably a film that is substantially neither heat-shrinkable nor self-stretchable. The synthetic resin film used as the film substrate for shrink labels is a film that is heat-shrinkable. The synthetic resin film used as the film substrate for stretch labels is a film that is self-stretchable.

[0026] The synthetic resin film may be transparent or opaque. Examples of opaque synthetic resin films include synthetic paper, films formed from resin materials containing colorants, and foamed resin films (including void-containing resin films). Preferably, the first film substrate 111 of the first label 110 is a transparent synthetic resin film, and the second film substrate 121 of the second label 120 is a transparent or opaque synthetic resin film.

[0027] <Adhesive Layer> Conventional adhesives can be used as adhesives for forming the adhesive layer 24, and typical examples include pressure-sensitive adhesives and heat-sensitive adhesives. When a pressure-sensitive adhesive is used, an adhesive label (on the back surface of the adhesive layer 24) is typically attached to a release liner (not shown). When a heat-sensitive adhesive is used, release liner is typically not required, but the label may be attached to the release liner. The adhesive layer 24 is preferably made of a material that does not dissolve or swell in the treatment solution used in the ink layer removal step, or that dissolves or swells less easily than the ink layers 112, 113, and 122. Using an adhesive layer 24 made of such a material makes it easier to obtain a substrate composite in which a second film substrate is laminated to a first film substrate via the adhesive layer after the ink layer removal step.

[0028] As the adhesive layer, known adhesives can be used, such as acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, mixtures thereof, etc.), silicone adhesives, polyester adhesives, urethane adhesives, polyether adhesives, polyamide adhesives, fluorine adhesives, and styrene adhesives.

[0029] [Substrate composite] Figure 2 is a schematic cross-sectional view showing an example of the configuration of a substrate composite obtained from the label composite of this embodiment through the ink layer removal process. As shown in Figure 2, the substrate composite 130 is a laminate in which a first label substrate 111 and a second label substrate 121 are laminated via an adhesive layer 124. The substrate composite 130 is obtained by removing the ink layers 112, 113, and 122 from the label composite 100.

[0030] In the substrate composite 130, the first label substrate 111 and the second label substrate 121 are preferably made of the same material or the same material. This is because a high-quality recycled material can be obtained even when the first label substrate 111 and the second label substrate 121 are processed without separating them, and the process can be prevented from becoming complicated. Furthermore, in the substrate composite 130, the first label substrate 111, the second label substrate 121, and the adhesive layer 124 are preferably made of the same material or the same material. This is because a high-quality recycled material can be obtained even when the first label substrate 111, the second label substrate 121, and the adhesive layer 124 are processed without separating them, and the process can be prevented from becoming complicated.

[0031] In the substrate composite 130, examples in which the first label substrate 111 and the second label substrate 121 are made of the same type of material or the same material include an example in which both the first label substrate 111 and the second label substrate 121 are made of a polyester-based resin material or a polyolefin-based resin material. As the polyester-based resin material, a polyethylene terephthalate-based resin material is preferred, and as the polyolefin-based resin material, a polypropylene-based resin material is preferred.

[0032] In the substrate composite 130, an example in which the first label substrate 111, the second label substrate 121, and the adhesive layer 124 are made of the same type of material or the same material includes an example in which the first label substrate 111 and the second label substrate 121 are both made of a polyester-based resin material, and the adhesive layer 124 is also made of an adhesive made of a polyester-based resin material. A substrate composite 130 in which the first label substrate 111, the second label substrate 121, and the adhesive layer 124 are all made of a polyester-based resin material is also referred to as a polyester-based substrate composite.

[0033] The adhesive made of a polyester resin contains a polyester resin as a base polymer. The polyester resin is a polymer containing a polyol and a polycarboxylic acid as monomer components constituting the polymer. That is, the polyester resin contains a structural unit derived from a polyol and a structural unit derived from a polycarboxylic acid. The polyester resin may be used alone or in combination of two or more types.

[0034] Examples of the polycarboxylic acid include dicarboxylic acids and trivalent or higher carboxylic acids. Examples of the dicarboxylic acid include aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, dimethylglutaric acid, adipic acid, trimethyladipic acid, pimelic acid, suberic acid, azelaic acid, dodecanedioic acid, sebacic acid, thiodipropionic acid, and diglycolic acid; dimer acids of unsaturated fatty acids; 1,2-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 4-methyl-1,2-cyclohexanedicarboxylic acid. Examples of suitable polycarboxylic acids include alicyclic dicarboxylic acids such as carboxylic acid, norbornanedicarboxylic acid, and adamantanedicarboxylic acid; unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, and dodecenyl succinic anhydride; aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid, orthophthalic acid, benzylmalonic acid, 2,2'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-dicarboxydiphenyl ether, and naphthalenedicarboxylic acid; and derivatives thereof. Examples of the derivatives include carboxylic acid salts, carboxylic acid anhydrides, carboxylic acid halides, and carboxylic acid esters. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, adamantanetricarboxylic acid, trimesic acid, and trimer acid. The polycarboxylic acids may be used singly or in combination of two or more.

[0035] Examples of the polyol include diols and trihydric or higher polyols. Examples of the diol include (poly)alkylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, and polytetramethylene glycol; 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-hexanediol, 2,2 aliphatic diols such as 1,4-trimethyl-1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol; dimer diol; alicyclic diols such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, spiroglycol, tricyclodecane dimethanol, adamantanediol, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol; and aromatic diols such as 4,4'-thiodiphenol, 4,4'-methylenediphenol, 4,4'-dihydroxybiphenyl, o-, m-, and p-dihydroxybenzene, 2,5-naphthalenediol, p-xylenediol, and ethylene oxide and propylene oxide adducts thereof. Examples of trihydric or higher polyols include pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, adamantanetriol, etc. Only one of the above polyols may be used, or two or more of them may be used.

[0036] The total content of the dicarboxylic acid-derived structural units and the diol-derived structural units in the polyester resin is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and particularly preferably 99% by mass or more (for example, 99 to 100% by mass), relative to 100% by mass of the total amount of structural units derived from monomers constituting the polyester resin.

[0037] [Method for Producing Recycled Material (First Embodiment)] Figure 3 is a diagram showing an example of a flow of the method for producing a recycled material according to this embodiment. As shown in Figure 3, the recycled material according to this embodiment includes a bottle recovery step S1, a compression step S2, an accumulation step S3, a label separation step S4, a sorting step S5, a crushing step S6, an ink layer removal step S7, and a separation / recovery step S8. The substrate composite 130, which serves as the raw material for the recycled material obtained in the separation / recovery step S8, is subjected to a recycled material production process to obtain recycled materials. Each step of the method for producing a recycled material will now be described with reference to Figure 3.

[0038] <Bottle Collection Process> First, as shown in S1 of Fig. 3, used PET bottles (items) 10 are collected in a collection box 12. The PET bottles 10 are made of a polyethylene terephthalate-based resin material (PET-based resin material). A label 11 is attached to the body of the PET bottle 10. The label 11 contains the label composite 100 described above. The substrate composite 130 obtained from the label composite 100 preferably contains a polyester-based substrate composite.

[0039] <Compression Step> Next, as shown in S2 of Fig. 3, the collected PET bottles 10 with the labels 11 attached are compressed to form labeled bales 20. Before compression, unwanted materials other than the PET bottles 10 may be removed.

[0040] <Collection Step> Next, as shown in S3 of FIG. 3, the labeled bales 20 are sent to a recycling factory 30 and collected.

[0041] <Label Separation Process> Next, as shown in S4 of Figure 3, at the recycling plant 30, the labels 11 are removed from the PET bottles 10 in the labeled bale 20, and the PET bottles 10 are separated from the labels 11. The labels 11 separated from the PET bottles 10 include the above-mentioned label composite 100, and may also include various other labels such as shrink labels, wrap labels, and stretch labels (hereinafter also referred to as "single labels").

[0042] In the illustrated example, shrink labels 11a and wrap-around labels 11b are shown as the labels 11 separated from the PET bottle 10. Here, the shrink labels 11a include the above-described label composite 100 in which the first label 110 is a shrink label, and may also include a single label that is a shrink label. The wrap-around labels 11b include the above-described label composite 100 in which the first label 110 is a wrap-around label, and may also include a single label that is a wrap-around label. The PET bottle 10 from which the label 11 has been separated is reused, for example, in an existing recycling process.

[0043] As shown in FIG. 1 , the label composite 100 is a laminate consisting of a first label 110 and a second label 120, where the first label 110 includes a first film substrate 111 and the second label 120 includes a second film substrate 121. The label composite 100 from which the ink layers 112, 113, and 122 have been removed becomes a substrate composite 130. The label alone from which the ink layer has been removed becomes a film substrate. Even if the label composite 100, substrate composite 130, label alone, or film substrate is crushed in a subsequent process, the crushed pieces may be referred to as the label composite, substrate composite, label alone, or film substrate. The label 11, which is a recovered material to be recycled, includes the label composite and the label alone, and the substrate composite and film substrate from which the ink layer has been removed can be recycled together. In this case, it is preferable that the label composite 100 contained in the label 11 of the collected item to be recycled is made up of the same type of material or the same material for the first label substrate 111, the second label substrate 121, the adhesive layer 124, and the film substrate, and it is even more preferable that these are polyester-based resin materials.

[0044] <Sorting Step> Next, the labels 11 are sorted as shown in S5 of Fig. 3. In the sorting step S5, the labels 11 are sorted, for example, by the type of film or material used in the labels 11. The illustrated example shows the labels 11 being sorted by the type of film used in the labels 11, i.e., into shrink labels 11a and wrap-around labels 11b, and then collected separately. If the shrink labels 11a and the wrap-around labels 11b are made of the same type or material, there is no need to separate them. An example of a case where the shrink labels 11a and the wrap-around labels 11b are made of the same type or material is when both are made of polyester-based resin.

[0045] The labels 11 obtained in the sorting step S5 are then subjected to the crushing step S6, the ink layer removing step S7, and the separation / recovery step S8. If the labels 11 are separated in the sorting step S5, the crushing step S6, the ink layer removing step S7, and the separation / recovery step S8 are separately performed on the separated labels 11.

[0046] The sorting step S5 is not essential and can be omitted. Also, for example, after the base material pieces 91 are collected in the separation / recovery step S9, the base material pieces 91 may be sorted by type or material.

[0047] <Crushing Step> Next, as shown in S6 of Fig. 3 , the label 11 is crushed by a crusher 70 to produce label pieces 71. In the crushing step S6, the ink layer is removed from the label 11 in the subsequent step S7, and prior to obtaining a substrate composite from the label composite or obtaining a label substrate from a single label, the label 11 is crushed into smaller label pieces 71. In this way, by performing step S7 in a state where the label 11 has been broken into smaller label pieces 71, the ink layer can be removed efficiently.

[0048] There is no particular limitation on the method for crushing the labels 11. In step S7 described below, the labels 11 are crushed into pieces of a size (e.g., several centimeters square) that allows for efficient removal of the ink layer.

[0049] The crushing step S6 is not essential and can be omitted. In this case, the step S7 is carried out in the state of the label 11.

[0050] <Ink Layer Removal Step> Next, as shown in step S7 of Figure 3, the ink layer is detached and removed from the label piece 71 to obtain a substrate piece 91. The substrate piece 91 includes a substrate composite piece obtained from a label composite piece, and may also include a label substrate piece obtained from a single label piece. Step S7 includes a solution treatment step S71 and may also include a water treatment step S72.

[0051] The solution treatment step S71 is a step in which the label piece 71 is brought into contact with a treatment solution 80. The treatment solution 80 is selected to dissolve or swell at least the ink layer (first ink layer) 112 of the label composite 100, and preferably to dissolve or swell all of the ink layers contained in the label piece 71. By selecting the treatment solution in this way, all of the ink layers contained in the label piece 71 can be removed simultaneously in step S7, eliminating the need for a separate step for removing the ink layers and reducing the complexity of the manufacturing method.

[0052] In step S7, the water treatment step S72 is not essential and can be omitted. Below, a case where step S7 includes the solution treatment step S71 and the water treatment step S72 (two-tank treatment) and a case where only the solution treatment step S71 is performed (one-tank treatment) will be described.

[0053] (Two-Bath Treatment) In the solution treatment step S71 of the two-bath treatment, for example, the label piece 71 is placed in the treatment solution 80 in the solution bath 82 and gently immersed for approximately 10 minutes. The temperature of the treatment solution 80 at this time can be normal temperature (approximately 15°C to 25°C) or room temperature (1°C to 30°C). This can reduce the adhesion of the ink layer while preventing complete detachment of the ink layer from the label piece 71 in the treatment solution 80. Note that the temperature of the treatment solution 80 means the surface temperature of the label piece 71 during the solution treatment step S71. "Gently immersed" refers to a state in which the treatment solution 80 is not agitated or is immersed very gently so as not to cause complete detachment of the ink layer.

[0054] The temperature of the treatment solution 80 in the solution bath 82 may be room temperature. However, from the perspective of efficiently removing the ink layer from the label piece 71, the temperature of the treatment solution 80 may be higher than room temperature. The treatment solution 80 is preferably alkaline, with a pH of approximately 11 to 14, and contains components that dissolve or swell the water-based ink layer and the oil-based ink layer at room temperature. In other words, the treatment solution 80 preferably contains both a component that dissolves or swells the water-based ink layer and a component that dissolves or swells the oil-based ink layer. By using such a treatment solution 80, the ink layer 112 can be efficiently removed, regardless of whether it is a water-based ink layer or an oil-based ink layer. Furthermore, all of the water-based ink layers and oil-based ink layers contained in the label piece 71 can be simultaneously dissolved or swelled, thereby separating and removing the ink layers from the label piece 71. Therefore, if the ink layers 113 and 122 are water-based ink layers or oil-based ink layers, they can also be removed. Furthermore, when the ink layers 112, 113, and 122 include an ultraviolet curable ink layer, the treatment solution 80 preferably further contains a component that dissolves or swells the ultraviolet curable ink layer.

[0055] The processing solution 80 may be, for example, a solution containing at least one component selected from the group consisting of an alkaline component, a surfactant, a glycol-based solvent (e.g., glycol ether), and a high-boiling-point solvent (e.g., polymeric alcohol). The processing solution 80 preferably contains an alkaline component and a surfactant. The processing solution 80 may also contain components other than those listed above. The surfactant may be an ionic surfactant (anionic surfactant, cationic surfactant, or zwitterionic surfactant) or a nonionic surfactant, or a combination of these components may be used. Examples of the alkaline component include alkali metal hydroxides such as sodium hydroxide (NaOH) or potassium hydroxide (KOH), alkali metal carbonates such as sodium carbonate (NaCO), alkali metal bicarbonates such as sodium bicarbonate (NaHCO), and ammonia water. The concentration of the alkaline component in the treatment solution 80 can be appropriately selected within a range that does not impair the releasability, operability, or workability of the ink layer, and is, for example, 0.1 to 10% by mass, preferably 0.5 to 5% by mass, and more preferably 1 to 4% by mass. By bringing the treatment solution 80 into contact with the ink layer or label, the water-based ink layer and / or oil-based ink layer can be dissolved or swelled at room temperature.

[0056] Alternatively, the treatment solution 80 may be a mixture of an aqueous ink remover containing a component that dissolves or swells the aqueous ink layer and an oil-based ink remover containing a component that dissolves or swells the oil-based ink layer. This makes it possible to easily produce a treatment solution 80 that contains both a component that dissolves or swells the aqueous ink layer and a component that dissolves or swells the oil-based ink layer.

[0057] The aqueous ink remover is not particularly limited as long as it dissolves or swells the aqueous ink layer at room temperature. The aqueous ink remover may be, for example, a commercially available aqueous ink remover for removing aqueous ink, or may be a commercially available agent (removal agent, cleaning agent, etc.) for purposes other than removing aqueous ink.

[0058] As such an aqueous ink remover, for example, a product named "Ventilation Fan Range Cleaner PRO" (manufactured by Rinrei Co., Ltd.) can be suitably used. Table 1 below shows an example of the composition and components of an aqueous ink remover (product named "Ventilation Fan Range Cleaner PRO") that can be suitably used in producing the treatment solution 80.

[0059]

[0060] As shown in Table 1, the aqueous ink remover can contain, for example, water, a glycol-based solvent (glycol ether), an amphoteric surfactant (alkyl betaine), sodium hydroxide, potassium hydroxide, a sequestering agent, and the like.

[0061] The oil-based ink remover is not particularly limited as long as it dissolves or swells the oil-based ink layer at room temperature. The oil-based ink remover may be, for example, a remover for oil-based ink that is commercially available for removing oil-based ink, or may be a chemical (remover, cleaner, etc.) that is commercially available for purposes other than removing oil-based ink.

[0062] As such an oil-based ink remover solution, for example, a product named "PAINTSOLV-W" manufactured by Infinity Co., Ltd. can be suitably used. Table 2 below shows an example of the composition and components of an oil-based ink remover (product name "PAINTSOLV-W") that can be suitably used in producing the treatment solution 80.

[0063] As shown in Table 2, the oil-based ink remover can contain, for example, a high-boiling point solvent (polymer alcohol-based solvent), a nonionic surfactant (lauryl glucoside), and the like.

[0064] By mixing an aqueous ink remover containing the components shown in Table 1 with an oil-based ink remover containing the components shown in Table 2 in a ratio of, for example, 1:9, it is possible to suitably produce a treatment solution 80 that dissolves or swells the ink layer at room temperature.

[0065] The water treatment step S72 is a step of contacting the label piece 71 having the ink layer with water 84 after the solution treatment step S71. In the water treatment step S72, the label piece 71 removed from the solution bath 82 is immersed in water 84 in a water bath 86 and agitated. In the illustrated example, the water 84 in which the label piece 71 is immersed is agitated by a screw 88 rotatably mounted on the bottom of the water bath 86. By agitating the water 84 in which the label piece 71 is immersed, the ink layer is released from the label piece 71 in the water 84, resulting in a substrate piece 91. The substrate piece 91 includes a substrate composite piece obtained from a label composite, and may also include a film substrate piece obtained from a label alone. For example, if the label piece 71 has an oil-based ink layer, the label piece 71 is separated into the substrate piece 91 and the ink coating film 93. If the label piece 71 has a water-based ink layer, the label piece 71 is also separated into the substrate piece 91 and the ink coating film 93. Therefore, whether the ink layer 112 of the label composite is an oil-based ink layer or an aqueous ink layer, the ink layer can be separated from the label piece 71 to obtain the substrate composite piece 91 or the film substrate piece. If the label piece 71 has an aqueous ink layer, the ink layer may dissolve and disperse in the water 84.

[0066] The temperature of the water 84 in the water tank 86 is not particularly limited, but is preferably about room temperature (around 27° C.) in order to avoid unintended shrinkage of the label strip 71 .

[0067] Thus, in the two-tank treatment, first, in the solution treatment step S71, the label piece 71 is gently immersed in the treatment solution 80. This prevents the ink layer from completely separating from the label piece 71 while reducing the adhesion between them in the treatment solution 80. At this time, the treatment solution 80 can dissolve or swell the water-based ink layer and the oil-based ink layer at room temperature. Then, in the subsequent water treatment step S72, the label piece 71 is immersed in water 84 and agitated, allowing the ink layer to be detached and removed from the label piece 71. At this time, a substrate composite piece is obtained from the label piece 71 of the label composite 100, and a label substrate piece is obtained from the label alone.

[0068] The processing solution 80 after immersing the label pieces 71 may be disposed of as waste liquid or may be reused. When the ink layer removal step S7 includes the water treatment step S72, as in the two-tank process, there is little change in the properties of the processing solution 80. This allows the processing solution 80 to be reused more efficiently. Examples of changes in the properties of the processing solution 80 include the inclusion of a large amount of ink layer.

[0069] (One-Bath Treatment) The solution treatment step S71 in the one-bath treatment can be performed by immersing the label pieces 71 in the treatment solution 80 and stirring it. In this way, the ink layers contained in the label composite and the label alone are dissolved or swelled and removed to obtain the substrate pieces 91. The substrate pieces 91 include substrate composite pieces obtained from the label composite, and may also include film substrate pieces obtained from the label alone.

[0070] The processing solution 80 used in the one-tank processing is the same as the processing solution 80 used in the two-tank processing. The time required for the solution processing step S71 in the one-tank processing varies depending on the stirring speed, the amount of label pieces 71 dropped into the processing solution 80, and the like, but is approximately 30 seconds to 20 minutes. This processing allows the substrate pieces and the ink coating to be efficiently separated in the processing solution 80. In the solution processing step S71, from the viewpoint of efficiently removing the ink layer from the label pieces 71, the temperature of the processing solution 80 is preferably 65°C or higher, more preferably 70°C to 95°C, and even more preferably 80°C to 90°C. The processing solution 80 after removing the ink layer from the label pieces may be disposed of as waste liquid, or may be reused as the processing solution 80 in the solution processing step S71.

[0071] In the one-tank treatment, it is preferable that the substrate piece 91 and the ink coating film obtained in the solution treatment step S71 are washed with water in a water washing step, and then subjected to the subsequent separation / recovery step.

[0072] <Separation / Recovery Step> Next, as shown in step S8 of Figure 3, the substrate pieces 91 and the ink coating 93 in the water tank 86 are separated and recovered. For example, a first net 90 with relatively large openings is used to collect the substrate pieces 91 after the ink layer has detached from the label pieces 71, and a second net 92 with relatively small openings is used to collect the ink coating 93, which is smaller than the substrate pieces 91. The ink coating 93 is a film formed by finely dividing the oil-based ink layer removed from the label pieces 71 in the ink layer removal step S7. In step S8, only the substrate pieces 91 may be collected without collecting the ink coating 93. In this case, it is sufficient to have only the first net 90 capable of collecting the substrate pieces 91, and a method of collecting the substrate pieces 91 with the first net 90 using centrifugation may also be used.

[0073] <Sorting step> The substrate pieces 91 include substrate composite pieces after the ink layer has been removed from the label composite pieces, and may also include film substrate pieces after the ink layer has been removed from the label pieces. The sorting step is a step of sorting the substrate composite pieces or film substrate pieces by material when they contain multiple types of materials. The sorting step may be performed before the separation / recovery step S8.

[0074] If the first and second film substrates constituting the substrate composite pieces, and the film substrates constituting the film substrate pieces, are made of the same or the same material, they may be separated from each other (without undergoing a separation process), and the raw material obtained from the mixture of substrate pieces may be supplied directly to the recycled material production process. Even if the materials are the same, they may be treated as different materials and separated in a separation process and supplied separately to the recycled material production process. If the materials are different, a separation process may be included to separate the substrate composite pieces and the film substrate pieces, and after separation, recycled materials may be obtained from the substrate composite pieces and the film substrate pieces, respectively. If the materials are different, a separation process may be included to separate them into the same or the same material, and after separation, recycled materials may be obtained from the substrate composite pieces and the film substrate pieces, respectively, as the same or the same material. Furthermore, if other film substrate pieces are contained in addition to the above, they may be removed rather than used as raw materials for the recycled material. Even if the materials are different, the raw material obtained from the mixture of substrate pieces may be supplied directly to the recycled material production process without separation.

[0075] When separating the substrate pieces 91 into substrate composite pieces and film substrate pieces, the separation method is not limited. For example, if one of the substrate composite pieces and the film substrate pieces has a specific gravity of 1 or more and the other has a specific gravity of less than 1, they can be separated by specific gravity using water. Specifically, if the film substrate pieces are made of a polyolefin-based resin with a specific gravity of less than 1 and the substrate composite pieces are made of a PET-based resin, a PS-based resin, or a composite thereof, they can be separated by specific gravity using water. The specific gravity separation can be performed in the solution treatment step S71 and the water treatment step S72 in the composite separation step S7, or in a water washing step separate from these.

[0076] The adhesive layer of the second label may be used as a raw material for recycling together with the substrate composite piece. In this case, the adhesive layer is preferably made of the same material as the first and second film substrates of the substrate composite piece, and more preferably, the first and second film substrates and adhesive layer of the substrate composite piece are all made of a polyester resin.

[0077] <Recycled Material Manufacturing Process> The base material pieces 91 are subjected to a process for obtaining a recycled material using the base material pieces, either through a sorting process or without a sorting process, through a dehydration process and a drying process.

[0078] The base material pieces 91 can be made into pelletized recycled material, for example, by undergoing a pelletizing process. In the pelletizing process, the base material pieces 91 can be melted and kneaded to form pellets (pelletized recycled material). The base material pieces 91 can also be made into recycled material in their state without being pelletized. When pellets are obtained, the base material pieces 91, which are the raw material, contain base material composite pieces. When such base material composite pieces are made of the same material, production efficiency is high and good quality pellets can be obtained.

[0079] Recycled materials can be used as raw materials for various products such as containers, label substrates, stationery, toys, and pallets. The recycled materials can be used alone or together with virgin materials. For example, when used as label substrates, the recycled materials and virgin materials can be melt-kneaded and formed into a film, which can then be used as a film substrate for labels.

[0080] <Other Steps> Among the substrate pieces 91, the substrate pieces separated from the substrate composite pieces and the ink coating film 93 collected by the second net 92 may be reused, for example, in a thermal recycling step.

[0081] The water-based ink released from the label piece 71 in the release step S7 dissolves and disperses in the treatment solution or water. Therefore, when recovering the water-based ink or the water-based ink and the oil-based ink, the separation / recovery step S8 can employ recovery methods such as precipitation, centrifugation, solvent evaporation, extraction, filtration, coagulation separation, squeezing, and other methods.

[0082] [Method for Producing Recycled Materials (Second Embodiment)] The method for producing recycled materials of the second embodiment differs from the first embodiment in that it does not include the label separation step S4 and the sorting step S5. This embodiment is suitable for cases in which the label 11 is made of a polyester-based resin and a polyester-based substrate composite is obtained by removing the ink layer from a label composite contained in the label 11. The label 11 may also contain a label unit in addition to the label composite. In this case, it is preferable that the film substrate of the label unit is made of a polyester-based resin material. In this embodiment, it is more preferable that the label-based substrate composite and the film substrate are made of a polyethylene terephthalate-based resin material, which is a polyester-based resin material.

[0083] In the first embodiment, in the label separation step S4 shown in Figure 3, the label 11 is removed from the PET bottle 10, and the bottle 10 and the label 11 are separated. In this embodiment, the label separation step S4 and the sorting step S5 are not performed, and the process proceeds directly to the shredding step S6, where the bottle 10 is shredded without separating the label 11 from the label 11, and not only the label fragments 71 but also the container fragments are obtained as crushed pieces. If the label fragments 71 are made of a polyester-based resin material and the container fragments are made of a polyethylene terephthalate-based resin material, they are not separated, and the subsequent processing, specifically the ink layer removal step S7 and the separation / recovery step S8, is performed. If the label fragments 71 contain materials other than polyester-based resin material, they may be separated and then subjected to the subsequent processing.

[0084] The crushing step S6, the ink layer removing step S7, the separation / recovery step S8, and other steps are the same as those described in the first embodiment, and therefore description thereof will be omitted here.

[0085] 11, 11a, 11b Label, 80 Treatment solution, 84 Water, 91 Substrate piece, 100 Label composite, 110 First label, 111 First film substrate, 112 Ink layer (first ink layer), 113 Ink layer, 120 Second label, 121 Second film substrate, 122 Ink layer (second ink layer), 124 Adhesive layer 130 Substrate composite.

Claims

1. A manufacturing method for producing recycled materials from recovered materials derived from containers with labels attached, wherein the recovered materials include a label composite, and the label composite is formed by laminating a first label having a first ink layer and a first film substrate, and a second label having an adhesive layer and a second film substrate, with the adhesive layer adhering to the first film substrate, the manufacturing method comprising: an ink layer removal step of removing the first ink layer from the label composite to obtain a substrate composite in which the second film substrate is laminated to the first film substrate with the adhesive layer interposed therebetween; and a recycled material manufacturing step of obtaining a recycled material using the substrate composite as a raw material after the ink layer removal step.

2. The manufacturing method described in claim 1, wherein the second label further has a second ink layer, and is laminated in the order of the adhesive layer, the second film substrate, and the second ink layer, and in the ink layer removal step, the second ink layer is removed from the label composite together with the first ink layer.

3. The manufacturing method according to claim 1 or 2, wherein in the label composite, the first film substrate, the second film substrate, and the adhesive layer are all made of a polyester-based resin material.

4. The manufacturing method according to claim 1 or 2, wherein the recovered material further includes a container, and the recycled material manufacturing process is a process for obtaining a recycled material using the substrate composite and the container as raw materials.

5. The manufacturing method according to claim 4, wherein the container is made of a polyethylene terephthalate resin material.

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