Deinking agent composition and method for deinking laminate

Abstract

To provide a deinking agent composition capable of sufficiently removing a printed layer from a resin laminate.SOLUTION: The deinking agent composition removes a printed layer from a laminate in which a resin layer and the printed layer are laminated, and contains a metal hydroxide, an alcohol having a carbon number of 3 or less, an aprotic polar solvent having an oxygen atom, and a nonionic surfactant having an HLB value of 6 or more and 18 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a deinking agent composition and a method for deinking a laminate. [Background technology]

[0002] Patent Document 1 discloses a technique for separating a multilayer film having a printed layer into its individual layers by immersing the multilayer film in a treatment liquid containing a polar solvent, a quaternary ammonium salt, and a surfactant. Such a treatment liquid dissolves the adhesive in the multilayer film and part of the multilayer structure, and in the process, the ink components of the printed layer also dissolve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7320890 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional techniques, the ink that constitutes the printed layer of the multilayer film hardens by reacting with the adhesive when the multilayer film is laminated, making it difficult to sufficiently remove the printed layer from the multilayer film.

[0005] An object of the present invention is to provide a deinking composition that can sufficiently remove a printed layer from a resin laminate. [Means for solving the problem]

[0006] The deinking composition of the present disclosure is a deinking composition that removes a printed layer from a laminate in which a resin layer and a printed layer are stacked, and contains a metal hydroxide, an alcohol having 3 or less carbon atoms, an aprotic polar solvent having an oxygen atom, and a nonionic surfactant with an HLB value of 6 or more and 18 or less. [Effects of the Invention]

[0007] According to one aspect of the present invention, a deinking agent composition can be provided that can sufficiently remove a printed layer from a resin laminate. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a plan view showing an example of a laminate; [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] FIG. 10 is a diagram showing the state of the laminate immersed in a deinking agent. [Figure 4] FIG. 10 is a diagram showing a state in which each resin layer has been peeled off from the laminate. DETAILED DESCRIPTION OF THE INVENTION

[0009] The laminate peeling method of the present disclosure will be described in detail with reference to the drawings. In each drawing, common parts are given the same reference numerals and their descriptions may be omitted. Furthermore, the scale of each member in each drawing may differ from the actual scale.

[0010] In this specification, directions in the drawings are explained using a three-dimensional Cartesian coordinate system of three axes (X, Y, and Z directions). In each drawing, the horizontal direction of the resin laminate is the X direction, the vertical direction of the resin laminate is the Y direction, and the thickness direction of the resin laminate is the Z direction. In addition, deviations in each direction are allowed to the extent that they do not impair the functions and effects of the present disclosure. Note that "parallel" may also include "approximately parallel."

[0011] <Deinking agent composition> The deinking agent composition of the present disclosure is used to remove a printed layer from a laminate comprising a resin layer and a printed layer. In this specification, "deinking agent" means an agent that acts on an object on which ink has been printed to remove the ink from the object. Furthermore, "remove" means not only completely removing the ink from the object on which ink has been printed, but also removing the ink to the extent that substantially no ink remains on the object on which ink has been printed.

[0012] The resin layer is a layer containing a resin. The resin layer may be formed of a resin sheet or a resin film. Examples of resins that constitute the resin layer include polyethylene (PE), polyethylene terephthalate (PET), and polyamide (PA). The resin layer may be a single layer or multiple layers.

[0013] In addition, when the resin layer is a multi-layer, the resin layer is two or more layers, preferably three or more layers. When the resin layer is a multi-layer, each resin layer may be composed of the same type of resin, or may be composed of different types of resin. When the resin layer is a multi-layer, each resin layer may be directly laminated, or each resin layer may be bonded via an adhesive layer described later.

[0014] Furthermore, when the resin layer constituting the laminate is multiple layers, the deinking agent composition of the present disclosure also peels the resin layer from the laminate. In this specification, "peeling" means that each resin layer naturally peels and separates from the laminate without applying a physical external force to the laminate.

[0015] The printing layer is a layer containing ink. The ink constituting the printing layer contains a colorant such as a dye and / or pigment, and a vehicle such as an aqueous and / or solvent-based resin. Examples of resins contained in the ink include acrylic resins, urethane resins, polyester resins, vinyl chloride resins, and vinyl acetate copolymer resins. These resins may be used alone or in combination of two or more.

[0016] The printing layer may further contain, as desired, plasticizers, stabilizers, antioxidants, light stabilizers, ultraviolet absorbers, curing agents, crosslinking agents, lubricants, antistatic agents, fillers, antifoaming agents, and the like.

[0017] The printed layer can be formed from an ink composition prepared by thoroughly kneading the ink with a solvent, a diluent, etc. In forming the printed layer, such an ink composition can be used to form a desired printed pattern consisting of letters, figures, symbols, designs, etc., using a printing method such as gravure printing, offset printing, letterpress printing, screen printing, transfer printing, or flexographic printing.

[0018] The printing layer may be laminated directly on the resin layer, or may be adhered to the resin layer via an adhesive layer described later. When the resin layer is a multi-layered layer, the printing layer may be laminated between the resin layers. Furthermore, a plurality of printing layers may be laminated.

[0019] 1 is a plan view of a resin laminate 100, which is an example of a laminate of the present disclosure. The shape of the resin laminate 100 is not particularly limited, and may be, for example, a regular shape in plan view, such as a triangle, a rectangle, a polygon, or a circle, or may be an irregular shape in plan view.

[0020] The size (area) of the resin laminate 100 is not particularly limited, but is preferably 0.1 cm 2 More than 20cm 2 or less, more preferably 0.15 cm 2 Over 15cm 2 Less than 0.2 cm, more preferably 2 More than 10cm 2 The following is the result.

[0021] In the present disclosure, as shown in FIGS. 1 and 2, a resin laminate 100 is composed of a first resin layer 10, a second resin layer 30, and a third resin layer 60.

[0022] The first resin layer 10, the second resin layer 30, and the third resin layer 60 may be made of a composite material in which different types of resins are used in some or all of the resin layers. For example, the first resin layer 10 may be made of polyethylene (PE) resin, the second resin layer 30 may be made of polyethylene terephthalate (PET) resin, and the third resin layer 60 may be made of polyamide (PA) resin.

[0023] The first resin layer 10, the second resin layer 30, and the third resin layer 60 may be mono-material layers in which the same type of resin is used for all of them. For example, the first resin layer 10, the second resin layer 30, and the third resin layer 60 may all be made of polyethylene (PE) resin.

[0024] Furthermore, when the first resin layer 10, the second resin layer 30, and the third resin layer 60 are all made of the same type of resin, the physical properties of the resin may differ among the resin layers. For example, the first resin layer 10 may be made of a linear low-density polyethylene (LLDPE) resin, the second resin layer 30 may be made of a medium-density polyethylene (MDPE) resin, and the third resin layer 60 may be made of a high-density polyethylene (HDPE) resin.

[0025] There are no particular limitations on the thickness of each of the first resin layer 10, the second resin layer 30, and the third resin layer 60. For example, the thickness of the first resin layer 10 is 60 to 100 μm, preferably 70 to 90 μm, and more preferably 75 to 85 μm. The thickness of the second resin layer 30 is 5 to 45 μm, preferably 15 to 35 μm, and more preferably 20 to 30 μm. The thickness of the third resin layer 60 is 5 to 45 μm, preferably 15 to 35 μm, and more preferably 20 to 30 μm.

[0026] In the resin laminate 100, a first adhesive layer 20 is formed between the first resin layer 10 and the second resin layer 30, and the first resin layer 10 and the second resin layer 30 are bonded together via the first adhesive layer 20. In addition, a second adhesive layer 40 is formed between the second resin layer 30 and the third resin layer 60, and the second resin layer 30 and the third resin layer 60 are bonded together via the second adhesive layer 40.

[0027] There are no particular limitations on the type of adhesive that constitutes the first adhesive layer 20 and the second adhesive layer 40. Examples of types of adhesive include two-component curing urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, and epoxy adhesives. Melt resins such as polyethylene can also be used as adhesives.

[0028] The mode of forming the adhesive layer is not particularly limited, and the adhesive layer can be formed by, for example, a sandwich lamination method, a dry lamination method, or the like.

[0029] The resin laminate 100 is further provided with a printed layer 50. The printed layer 50 is formed by printing and applying the ink composition described above to the surface of the third resin layer 60 on the side of the second resin layer 30. This makes the printed layer visible from the third resin layer 60 side of the resin laminate 100, as shown in FIG.

[0030] The resin laminate 100 may further include any other layer such as a barrier layer, an anchor coat layer, a functional layer, or a surface coat layer.

[0031] Furthermore, the barrier layer (not shown) can be formed, for example, by laminating a metal foil on the surface of the second resin layer 30 facing the third resin layer 60, or by forming the second resin layer 30 into a vapor-deposited film on which a metal or metal oxide is vapor-deposited.

[0032] The metal foil may be an aluminum foil or the like, and the thickness thereof may be 5 μm or more and 20 μm or less.

[0033] Examples of the vapor-deposited film that can be used include a polyethylene terephthalate film having a metal vapor-deposited layer such as aluminum or an inorganic vapor-deposited layer such as alumina or silica, and a polypropylene film having a metal vapor-deposited layer such as aluminum or an inorganic vapor-deposited layer such as alumina or silica.

[0034] The resin laminate 100 may have through holes (not shown), slits (not shown), and the like formed therein.

[0035] When forming through holes in the resin laminate 100, the form of the through holes is not particularly limited, and for example, a metal needle is pierced in the thickness direction of the resin laminate 100 to form through holes (not shown) in the resin laminate 100. The shape of the through holes is not particularly limited, and may be, for example, a circle, an ellipse, a triangle, a rectangle, a polygon with pentagons or more sides, etc., and is preferably a circle.

[0036] When the through-holes have a circular shape, the diameter of the through-holes is preferably 100 μm or more and 500 μm or less, more preferably 110 μm or more and 490 μm or less, and even more preferably 120 μm or more and 480 μm or less.

[0037] The density of the through holes is not particularly limited, but is preferably 1 hole / cm 2 More preferably, 2 particles / cm 2 More preferably, 3 pieces / cm 2 The upper limit of the density of the through holes is not particularly limited, but the practical upper limit is 300 holes / cm. 2 less than 200 particles / cm 2 Less than 100 / cm, more preferably 2 The following is the result.

[0038] When three or more through holes are formed in the resin laminate 100, the arrangement of the through holes is not particularly limited. For example, 25 through holes may be arranged at equal intervals vertically and horizontally or regularly in the resin laminate 100. Alternatively, the 25 through holes may be arranged randomly or irregularly in the resin laminate 100. Note that, from the viewpoint of allowing the deinking agent composition to penetrate uniformly between the layers of the resin laminate 100 through the through holes, it is preferable to arrange the through holes regularly.

[0039] When forming slits in the resin laminate 100, the form of the slits is not particularly limited, and for example, a slit (not shown) is formed in the resin laminate 100 by making an incision in the thickness direction of the resin laminate 100 with a metal blade. Note that when forming the slits, it is preferable not to cut out a part of the resin laminate 100 in order to avoid generating excess waste.

[0040] The shape of the slit is not particularly limited, and may be any of a straight line, a curved line, or a combination of a straight line and a curved line, but is preferably a straight line.

[0041] The width of the slit is not particularly limited, but is, for example, the width of the cut made by the blade die described above, and is preferably 1 mm or less, more preferably 0.1 mm or less.

[0042] The direction of the slits is not particularly limited. For example, the square resin laminate 100 shown in Fig. 1 may have slits extending parallel to the sides facing each other in the horizontal direction (X direction) of the square. Alternatively, the square resin laminate 100 shown in Fig. 1 may have slits extending obliquely to each side of the square.

[0043] The length of the slit is not particularly limited. For example, when the length of each side of the square resin laminate 100 shown in Fig. 1 is 100%, the length of the slit is 20% or more, preferably 40% or more, and more preferably 60% or more.

[0044] The number of slits is not limited to one, and may be two or more. When two or more slits are formed in the resin laminate 100, the arrangement of each slit is not limited. For example, the two or more slits may be arranged so that they are parallel to one another or intersect with one another. Furthermore, two or more slits arranged in parallel to one another may be arranged at equal intervals. Furthermore, when two or more slits are formed, the lengths of the slits may be the same or different.

[0045] As shown in Fig. 3, the resin laminate 100 is immersed in a treatment liquid 80 containing the deinking agent composition of the present disclosure, which is placed in an immersion bath 70. As a result, the resin laminate 100 is peeled into a first resin layer 10, a second resin layer 30, and a third resin layer 60, as shown in Fig. 4. The treatment liquid 80 in the immersion bath 70 becomes a treatment liquid 80' in which the adhesives that make up the first adhesive layer 20 and the second adhesive layer 40 and the ink composition that makes up the printing layer 50 are dissolved.

[0046] As described above, when through holes are formed in the resin laminate 100, the treatment liquid 80 can easily penetrate through the through holes between the resin layers and the printed layers or between the resin layers of the resin laminate 100. Furthermore, when slits are formed in the resin laminate 100 as described above, the ends of the slits can be formed in positions close to the edges of the resin laminate 100, so that the treatment liquid 80 can easily penetrate between the ends of the slits and the edges of the resin laminate 100.

[0047] Therefore, by providing through holes or slits in the resin laminate 100, the time from when the resin laminate is immersed in the treatment liquid 80 until each resin layer is peeled off can be shortened, so that each resin layer can be efficiently separated or isolated from the resin laminate even if the resin layer is multiple layers.

[0048] The deinking agent composition of the present disclosure contains a metal hydroxide, an alcohol having 3 or less carbon atoms, an aprotic polar solvent having an oxygen atom, and a nonionic surfactant having an HLB value of 6 or more and 18 or less.

[0049] The metal hydroxide is not particularly limited, but is preferably an alkali metal hydroxide, and among these, sodium hydroxide and potassium hydroxide are more preferred. The metal hydroxide may be used alone or in combination of two or more kinds.

[0050] The content of metal hydroxide in the deinking agent composition is not particularly limited, but is, for example, 1% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 25% by mass or less, and even more preferably 7% by mass or more and 15% by mass or less. If the content of metal hydroxide is 1% by mass or more and 40% by mass or less, layers other than the resin layers, such as adhesive layers, metal vapor deposition layers, and colored layers, present between the resin layers in the resin laminate, tend to decompose.

[0051] The alcohol having 3 or less carbon atoms is not particularly limited, but may be, for example, a lower alcohol such as methanol, ethanol, 1-propanol, or 2-propanol, with methanol and ethanol being preferred. These lower alcohols may be used alone or in combination of two or more.

[0052] The content of the alcohol having 3 or less carbon atoms in the deinking agent composition is not particularly limited, but is, for example, 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less, and even more preferably 30% by mass or more and 40% by mass or less. If the content of the alcohol having 3 or less carbon atoms is 10% by mass or more and 60% by mass or less, the adhesive layer in the resin laminate becomes more likely to decompose.

[0053] Aprotic polar solvents refer to polar solvents that do not have proton-donating properties (the ability to release hydrogen atoms as protons). Aprotic polar solvents containing oxygen atoms are polar solvents that have at least one functional group such as a carbonyl group, a carboxyl group, a nitro group, a nitroso group, a sulfonic acid group, a sulfonyl group, or a sulfoxide group, and at least one bond such as an ether bond or an ester bond. Of these, the aprotic polar solvents containing oxygen atoms are preferably organic solvents that have a carbonyl group, a nitroso group, a sulfoxide group, or an ether bond.

[0054] Examples of aprotic polar solvents having an oxygen atom include anisole, methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, 3,5-dimethylanisole, tetrahydrofuran, 2-methyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, sulfolane, etc. Among these, anisole, N-methyl-2-pyrrolidone, and dimethyl sulfoxide are particularly preferred.

[0055] The aprotic polar solvent having an oxygen atom is preferably an organic solvent having a boiling point of 60°C or higher and 260°C or lower, more preferably an organic solvent having a boiling point of 100°C or higher and 240°C or lower, and even more preferably an organic solvent having a boiling point of 150°C or higher and 210°C or lower.

[0056] The aprotic polar solvent having an oxygen atom is preferably an organic solvent having an SP value of 5 or more and 20 or less, more preferably an organic solvent having an SP value of 7 or more and 17 or less, and even more preferably an organic solvent having an SP value of 9 or more and 15 or less. Here, the SP value is an index value of the molecular cohesion property of a compound, and is theoretically calculated from the cohesion energy and molar volume of atoms and atomic groups based on the Fedors constant.

[0057] The content of the aprotic polar solvent having an oxygen atom in the deinking agent composition is not particularly limited, but is, for example, 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less. When the content of the aprotic polar solvent having an oxygen atom is 20% by mass or more and 80% by mass or less, the ink in the cured printing layer becomes more likely to be softened, making deinking of the resin laminate easier. In addition, the decomposed adhesive layer becomes more likely to dissolve in the deinking agent composition.

[0058] A nonionic surfactant is a surfactant that does not ionize in water. A nonionic surfactant with an HLB value of 6 to 18 is a hydrophilic nonionic surfactant. Here, the HLB value represents the balance between the hydrophobicity and hydrophilicity of a surfactant; a smaller HLB value represents a more hydrophobic surfactant, and a larger HLB value represents a more hydrophilic surfactant.

[0059] Furthermore, the nonionic surfactant having an HLB value of 6 or more and 18 or less is preferably a nonionic surfactant having an HLB value of 7.5 or more and 17 or less, more preferably a nonionic surfactant having an HLB value of 8 or more and 15 or less, and even more preferably a nonionic surfactant having an HLB value of 8.5 or more and 13 or less.

[0060] Furthermore, nonionic surfactants having an HLB value of 6 or more and 18 or less preferably have 1 or more and 25 or less repeating units of ethylene oxide or propylene oxide, more preferably 2 or more and 20 or less repeating units of ethylene oxide or propylene oxide, and even more preferably 5 or more and 10 or less repeating units of ethylene oxide or propylene oxide. Here, the repeating unit means a unit derived from a monomer formed by polymerization of the monomer.

[0061] The content of the nonionic surfactant having an HLB value of 6 or more and 18 or less in the deinking agent composition is not particularly limited, but is, for example, 1% by mass or more and 12% by mass or less, more preferably 3% by mass or more and 10% by mass or less, and even more preferably 5% by mass or more and 8% by mass or less. When the content of the nonionic surfactant having an HLB value of 6 or more and 18 or less is 1% by mass or more and 12% by mass or less, the ink of the softened printing layer becomes more easily dissolved in the deinking agent composition.

[0062] The deinking agent composition of the present disclosure is substantially free of quaternary ammonium salts. In this specification, "substantially free of quaternary ammonium salts" means that they are not intentionally added, except in cases where they are inevitably mixed in from raw materials, etc. Quaternary ammonium salts are known to exhibit high environmental toxicity, but the deinking agent composition of the present disclosure is substantially free of such quaternary ammonium salts, making it possible to provide a deinking agent with low environmental toxicity.

[0063] The deinking agent composition of the present disclosure is substantially free of water. Here, "substantially free of water" means that water is not intentionally added, except in cases where water is inevitably mixed in from the air or raw materials, etc. By being substantially free of water, the deinking agent composition of the present disclosure improves the compatibility between the ink of the softened printing layer and the deinking agent composition, making it easier for the ink of the softened printing layer to dissolve in the deinking agent composition.

[0064] The deinking agent composition of the present disclosure may optionally contain one or more stabilizers, antioxidants, dispersants, and the like.

[0065] As described above, the deinking composition of the present disclosure contains a metal hydroxide, an alcohol with a carbon number of 3 or less, an aprotic polar solvent having an oxygen atom, and a nonionic surfactant with an HLB value of 6 or more and 18 or less. When the deinking composition comes into contact with a laminate, the adhesive components of the adhesive layer in the laminate are more likely to decompose, making it easier for the resin layer and printing layer of the laminate to separate.

[0066] Furthermore, when the deinking composition comes into contact with the printed layer, the ink in the printed layer that hardened by reaction with the adhesive during lamination of the laminate tends to soften, making the softened ink more likely to decompose. Furthermore, the adhesive components of the decomposed adhesive layer and the softened ink in the printed layer tend to dissolve more easily in the deinking composition. Therefore, the deinking composition of the present disclosure makes it easier to remove the printed layer from a laminate in which a resin layer and a printed layer are laminated, or to deink the laminate.

[0067] Furthermore, when a laminate has two or more resin layers, the adhesive layer or some of the resin layers in the laminate tend to decompose, making each resin layer of the laminate more likely to peel off. Therefore, the deinking agent composition of the present disclosure can separate or isolate each resin layer from a laminate having two or more resin layers, regardless of whether the laminate is a composite material or a monomaterial, making it easy to separate each resin layer and enabling the reuse of each resin layer in the laminate.

[0068] In the deinking agent composition of the present disclosure, as described above, the metal hydroxide is an alkali metal hydroxide, which makes it easier to decompose the adhesive components of the adhesive layer in the laminate, making it even easier to deink the laminate.

[0069] In the deinking agent composition of the present disclosure, as described above, by using an organic solvent with a boiling point of 60°C or higher and 260°C or lower as the aprotic polar solvent having oxygen atoms, the ink of the printing layer that hardens by reaction with the adhesive during lamination of the laminate becomes more likely to soften. In addition, the adhesive components of the decomposed adhesive layer become more likely to dissolve in the deinking agent composition. This makes deinking of the laminate even easier.

[0070] Furthermore, as mentioned above, using an organic solvent with an SP value of 5 to 20 as the aprotic polar solvent having an oxygen atom also makes it easier to soften the ink in the cured printing layer. Also, the adhesive components of the decomposed adhesive layer are more likely to dissolve in the deinking agent composition. This makes it even easier to deink the laminate.

[0071] In the deinking composition of the present disclosure, as described above, by using a nonionic surfactant having ethylene oxide or propylene oxide repeating units of 1 to 25 as the nonionic surfactant with an HLB value of 6 to 18, the ink in the softened printing layer becomes more easily soluble in the deinking composition, making it even easier to deink the laminate.

[0072] <Method for deinking laminate> The laminate deinking method of the present disclosure is a method for removing a printed layer from a laminate. In this laminate deinking method, the laminate can be a laminate in which the resin layer and printed layer described above are stacked. The resin laminate 100 shown in Figures 1 and 2 is an example of a laminate in the laminate deinking method, with the first resin layer 10, second resin layer 30, and third resin layer 60 being examples of resin layers, and the printed layer 50 being an example of a printed layer.

[0073] The deinking method for a laminate according to the present disclosure includes an immersion step. In the immersion step, the laminate is immersed in a deinking agent composition. The manner in which the laminate is immersed in the deinking agent composition is not particularly limited. In the present disclosure, for example, as shown in FIG. 3, a resin laminate 100 is immersed in a treatment liquid 80 containing the above-mentioned deinking agent composition contained in an immersion bath 70.

[0074] In the laminate deinking method of the present disclosure, the above-mentioned deinking agent composition is used. That is, in the immersion step, the resin laminate 100 is immersed in a treatment liquid 80 of the deinking agent composition containing the above-mentioned metal hydroxide, an alcohol having 3 or less carbon atoms, an aprotic polar solvent having an oxygen atom, and a nonionic surfactant with an HLB value of 6 or more and 18 or less.

[0075] The temperature of the treatment liquid 80 containing the deinking agent composition is not particularly limited. The temperature of the treatment liquid 80 is, for example, 20°C or higher, preferably 30°C or higher and 90°C or lower, and more preferably 40°C or higher and 80°C or lower.

[0076] By setting the temperature of the treatment liquid containing the deinking agent composition to 20°C or higher, the first resin layer 10, the second resin layer 30, and the third resin layer 60 can be peeled off from the resin laminate 100 even at room temperature. Furthermore, by setting the temperature of the treatment liquid to 40°C or higher and 80°C or lower, the rate at which layers other than the resin layers present between the resin layers that make up the resin laminate, such as adhesive layers, metal vapor deposition layers, and printed layers, are dissolved increases. This makes it possible to further shorten the time from immersion of the resin laminate in the treatment liquid until each resin layer is peeled off, thereby enabling more efficient separation of each resin layer from the resin laminate even in cases where the resin layer is multilayered.

[0077] Furthermore, in the immersion step, physical treatment such as stirring the treatment liquid 80 or applying ultrasonic vibrations to the treatment liquid 80 may be optionally added. By adding such physical treatment, some of the resin layers of the resin laminate 100, and adhesive layers or printed layers between the resin layers can be efficiently decomposed and dissolved.

[0078] In addition, in the laminate deinking method of the present disclosure, as described above, if a through hole is to be formed in the resin laminate 100, a through hole forming step may be performed, and if a slit is to be formed in the resin laminate 100, a slit forming step may be performed, both of which may be performed before the immersion step.

[0079] By carrying out such a through hole forming process and a slit forming process, as described above, the time from when the resin laminate is immersed in the treatment liquid 80 until each resin layer is peeled off can be shortened, so that each resin layer can be efficiently separated or isolated from the resin laminate even when the resin layer is multiple layers.

[0080] In the method for deinking a laminate of the present disclosure, the use of the above-mentioned deinking agent composition can provide the same effects as the deinking agent composition of the present disclosure.

[0081] In other words, according to the laminate deinking method disclosed herein, the deinking composition into which the laminate is immersed contains a metal hydroxide, an alcohol with a carbon number of 3 or less, an aprotic polar solvent having an oxygen atom, and a nonionic surfactant with an HLB value of 6 or more and 18 or less, so that when the deinking composition comes into contact with the laminate, the adhesive components of the adhesive layer in the laminate are more likely to decompose, making it easier for the resin layer and printing layer of the laminate to separate.

[0082] Furthermore, when a laminate has two or more resin layers, the adhesive layer or some of the resin layers in the laminate tend to decompose, making it easier for each resin layer in the laminate to peel off. Therefore, the laminate deinking method of the present disclosure can separate or isolate each resin layer from the laminate, regardless of whether the laminate has two or more resin layers and is a composite material or a monomaterial, making it easy to separate each resin layer and enabling the reuse of each resin layer in the laminate.

[0083] Furthermore, according to the deinking method for laminates of the present disclosure, when the deinking composition comes into contact with the printed layer, the ink in the printed layer that hardened by reaction with the adhesive during lamination of the laminate is more likely to soften, making the softened ink more likely to decompose. Furthermore, the adhesive components of the softened adhesive layer and the decomposed ink in the printed layer are more likely to dissolve in the deinking composition. Therefore, the deinking composition of the present disclosure makes it easier to deink laminates. [Example]

[0084] The present invention will be described in more detail below with reference to examples. The examples and comparative examples were evaluated by the following tests. In the following, numerical values ​​without units or "parts" are based on mass unless otherwise specified.

[0085] [Laminate (test specimen)] A resin laminate consisting of three resin layers was prepared as the laminate (test specimen). The resin laminate is a composite material consisting of a 15μm (polyamide (PA) resin layer / printed layer) / a 2μm adhesive layer / a 12μm (aluminum vapor deposition layer / polyethylene terephthalate (PET) resin layer) / a 2μm adhesive layer / a 100μm linear low-density polyethylene (LLDPE) resin layer. The adhesive layer is a cured urethane material. The size of the test specimen was a 10mm x 10mm square when viewed in plan.

[0086] [Deinking agent composition (treatment liquid)] The deinking agent compositions (treatment solutions) were formulated according to the compositions shown in Tables 1 and 2. In Table 1, Solutions 1 to 3 are mixtures of alkali metal hydroxide and alcohols with three or fewer carbon atoms. Of these, Solution 1 is a mixture of potassium hydroxide (KOH) and methanol (MeOH), Solution 2 is a mixture of sodium hydroxide (NaOH) and methanol (MeOH), and Solution 3 is a mixture of potassium hydroxide (KOH) and ethanol (EtOH). In Table 2, N-methyl-2-pyrrolidone (NMP), anisole, and dimethyl sulfoxide (DMSO) are aprotic polar solvents containing oxygen atoms, and the surfactant is a nonionic surfactant with an HLB value of 10.5 and seven ethylene oxide repeating units. In Solutions 1 to 3, the total of all components is 100%.

[0087] [Removability] The resin laminate (test specimen) was immersed in a treatment solution at 60°C for 30 minutes while stirring, and then it was confirmed whether each resin layer peeled off naturally from the resin laminate (peelability) without using tweezers, etc. Peelability was evaluated according to the following criteria. [Evaluation criteria] Good: Peeled off Poor: Did not peel off

[0088] [Deinking property] The resin laminate (test specimen) was immersed in the treatment liquid for 30 minutes while stirring, and then it was visually confirmed whether the resin laminate (test specimen) or the peeled resin layer had become transparent (deinking ability). [Evaluation criteria] Good: Deinked Defective: Not deinked

[0089] Examples and comparative examples are listed below.

[0090] [Example 1] The test specimen was immersed in a treatment liquid containing 5 parts of Solution 1, 5 parts of NMP, and 1 part of a surfactant, and the peelability and deinking properties were evaluated. The conditions and results of Example 1 are shown in Tables 1 and 2.

[0091] [Example 2] A treatment liquid prepared by mixing Solution 2 instead of Solution 1 was used. Except for this, the test and evaluation were carried out in the same manner as in Example 1. The conditions and results of Example 2 are shown in Tables 1 and 2.

[0092] [Example 3] A treatment liquid prepared by mixing Solution 3 instead of Solution 1 was used. Except for this, the test and evaluation were carried out in the same manner as in Example 1. The conditions and results of Example 3 are shown in Tables 1 and 2.

[0093] [Example 4] A treatment liquid containing anisole was used instead of NMP. Except for this, the test and evaluation were carried out in the same manner as in Example 1. The conditions and results of Example 4 are shown in Tables 1 and 2.

[0094] [Example 5] A treatment liquid containing DMSO instead of NMP was used. Except for this, the test and evaluation were carried out in the same manner as in Example 1. The conditions and results of Example 5 are shown in Tables 1 and 2.

[0095] [Comparative Example 1] A treatment liquid containing cyclohexane (a non-polar solvent) was used instead of NMP. Except for this, the test and evaluation were carried out in the same manner as in Example 1. The conditions and results of Comparative Example 1 are shown in Tables 1 and 2.

[0096] Comparative Example 2 A treatment liquid containing no surfactant was used. Except for this, the test and evaluation were carried out in the same manner as in Example 1. The conditions and results of Comparative Example 2 are shown in Tables 1 and 2.

[0097] Comparative Example 3 A treatment liquid containing no surfactant was used. Except for this, the test and evaluation were carried out in the same manner as in Example 4. The conditions and results of Comparative Example 3 are shown in Tables 1 and 2.

[0098] Comparative Example 4 A treatment liquid containing DMSO instead of NMP and no surfactant was used. Except for this, the test and evaluation were carried out in the same manner as in Example 2. The conditions and results of Comparative Example 4 are shown in Tables 1 and 2.

[0099] Comparative Example 5 A treatment liquid containing cyclohexane instead of NMP and no surfactant was used. Except for this, the test and evaluation were carried out in the same manner as in Example 3. The conditions and results of Comparative Example 5 are shown in Tables 1 and 2.

[0100] [Table 1]

[0101] [Table 2]

[0102] As can be seen from Tables 1 and 2, in Examples 1 to 5, when a deinking agent composition containing a metal hydroxide, an alcohol having 3 or less carbon atoms, an aprotic polar solvent having an oxygen atom, and a nonionic surfactant with an HLB value of 6 or more and 18 or less was used as the treatment liquid, both the stripping property and the deinking property were good.

[0103] On the other hand, when a treatment liquid that did not contain an aprotic polar solvent having oxygen atoms was used, as in Comparative Example 1, and when a treatment liquid that did not contain a surfactant was used, as in Comparative Examples 2 to 5, the deinking properties were poor in both cases.

[0104] The above-disclosed embodiments include, for example, the following aspects.

[0105] <1> A deinking agent composition for removing a printed layer from a laminate in which a resin layer and a printed layer are laminated, comprising: a metal hydroxide; Alcohols with 3 or fewer carbon atoms, an aprotic polar solvent having an oxygen atom; A deinking agent composition containing a nonionic surfactant having an HLB value of 6 or more and 18 or less.

[0106] <2> The metal hydroxide is an alkali metal hydroxide. <1> The deinking agent composition described in

[0107] <3> The aprotic polar solvent is an organic solvent having a boiling point of 60°C or higher and 260°C or lower. <1> or <2> The deinking agent composition described in

[0108] <4> The nonionic surfactant has 1 or more and 25 or less repeating units of ethylene oxide or propylene oxide. <1> ~ <3> The deinking agent composition according to any one of the preceding claims.

[0109] <5> The above, which is substantially free of quaternary ammonium salts <1> ~ <4> The deinking agent composition according to any one of the preceding claims.

[0110] <6> The above, which is substantially free of water <1> ~ <5> The deinking agent composition according to any one of the preceding claims.

[0111] <7> The laminate has two or more resin layers. <1> ~ <6> The deinking agent composition according to any one of the preceding claims.

[0112] <8> A deinking method for a laminate in which a resin layer and a printing layer are laminated, comprising the steps of: removing the printing layer from the laminate; The laminate is <1> ~ <7> A method for deinking a laminate, comprising a step of immersing the laminate in the deinking agent composition according to any one of the preceding claims.

[0113] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the invention described in the claims. [Explanation of symbols]

[0114] 100 Resin laminate 10 First resin layer 20 First adhesive layer 30 Second resin layer 40 Second adhesive layer 50 printing layers 60 Third resin layer 70 Immersion bath 80 Processing liquid 80´ Processing liquid in which ink is dissolved

Claims

1. A deinking agent composition for removing a printed layer from a laminate in which a resin layer and a printed layer are laminated, comprising: a metal hydroxide; an alcohol having three or fewer carbon atoms; an aprotic polar solvent having an oxygen atom; A deinking agent composition comprising a nonionic surfactant having an HLB value of 6 or more and 18 or less.

2. The deinking agent composition according to claim 1, wherein the metal hydroxide is an alkali metal hydroxide.

3. The deinking agent composition according to claim 1, wherein the aprotic polar solvent is an organic solvent having a boiling point of 60°C or higher and 260°C or lower.

4. The deinking agent composition according to claim 1, wherein the nonionic surfactant has 1 or more and 25 or less repeating units of ethylene oxide or propylene oxide.

5. The deinking agent composition according to claim 1, which is substantially free of quaternary ammonium salts.

6. The deinking agent composition according to claim 1, which is substantially free of water.

7. The deinking agent composition according to claim 1, wherein the laminate has two or more resin layers.

8. A deinking method for a laminate in which a resin layer and a printing layer are laminated, comprising the steps of: removing the printing layer from the laminate; A method for deinking a laminate, comprising the step of immersing the laminate in the deinking agent composition according to any one of claims 1 to 7.

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