Method for peeling laminate

Abstract

To provide a method for peeling a laminate that can efficiently separate each resin from a resin laminate without requiring large-scale equipment.SOLUTION: A method for peeling a laminate that peels a resin layer from a resin laminate in which multiple resin layers are laminated comprises the steps of forming slits in the resin laminate and immersing the resin laminate in which the slits are formed in a peeling solution.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for peeling off a laminate. [Background technology]

[0002] In order to separate and recover a laminated film that has been laminated with an adhesive, a method is known in which the laminated film is immersed in an alkaline solution to peel off each layer into a single layer film (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6777263 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method of peeling the monolayer film from the laminate film, when the laminate film is immersed in a peeling liquid such as an alkaline solution, a large-scale facility is required for stirring or ultrasonically vibrating the laminate film, etc. In addition, it takes a certain amount of time from when the laminate film is immersed in the alkaline solution until each monolayer film is peeled off.

[0005] An object of the present invention is to provide a method for peeling a laminate, which can efficiently separate each resin layer from a resin laminate having a plurality of resin layers stacked therein, without requiring large-scale equipment. [Means for solving the problem]

[0006] The laminate peeling method disclosed herein is a laminate peeling method for peeling a resin layer from a resin laminate having a plurality of resin layers stacked therein, and includes the steps of forming a slit in the resin laminate and immersing the resin laminate with the slit formed in it in a peeling liquid. Effect of the Invention

[0007] According to one aspect of the present invention, it is possible to efficiently separate each resin layer from a resin laminate in which a plurality of resin layers are laminated, without requiring large-scale equipment. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a plan view showing an example of a resin laminate. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view of FIG. [Figure 4] FIG. 11 is a plan view showing a first modified example of the resin laminate. [Diagram 5] FIG. 11 is a plan view showing a second modified example of the resin laminate. [Figure 6] FIG. 11 is a plan view showing a third modified example of the resin laminate. [Figure 7] FIG. 13 is a plan view showing a fourth modified example of the resin laminate. [Figure 8] FIG. 13 is a plan view showing a fifth modified example of the resin laminate. [Figure 9] FIG. 13 is a plan view showing a sixth modified example of the resin laminate. [Figure 10] FIG. 13 is a plan view showing a seventh modified example of the resin laminate. [Figure 11] FIG. 13 is a plan view showing an eighth modified example of the resin laminate. [Figure 12] FIG. 13 is a plan view showing a ninth modified example of the resin laminate. [Figure 13] FIG. 23 is a plan view showing a tenth modified example of the resin laminate. [Figure 14] FIG. 15 is a plan view showing an eleventh modified example of the resin laminate. [Figure 15] FIG. 2 is a diagram showing a state in which the resin laminate is immersed in a stripping liquid. [Figure 16] FIG. 2 is a diagram showing a state in which each resin layer has been peeled off from the resin laminate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The method for peeling off a laminate according to the present disclosure will be described in detail with reference to the drawings. In each drawing, the same reference numerals may be used to designate common parts, and the description may be omitted. In each drawing, the scale of each member may differ from the actual scale.

[0010] In this specification, the directions of the figures are described using a three-dimensional orthogonal coordinate system of three axial directions (X direction, Y direction, and Z direction). In each figure, 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 an extent that do not impair the functions and effects of the present disclosure. Note that parallel, perpendicular, center, and square may also include approximately parallel, approximately perpendicular, approximately center, and approximately square.

[0011] The method for peeling a laminate according to the present disclosure is a method for peeling a resin layer from a resin laminate. The resin laminate is a laminate in which a plurality of resin layers are laminated. "Peeling a resin layer" refers to naturally peeling each resin layer from the resin laminate without applying a physical external force to the resin laminate.

[0012] There is no particular limitation on the shape of the resin laminate 100. The shape of the resin laminate 100 may be, for example, a regular shape in a planar view, such as a triangle, a rectangle, a polygon, or a circle, or may be an irregular shape in a planar view.

[0013] The size (area) of the resin laminate 100 is not particularly limited, but is preferably 0.1 cm 2 More than 20cm 2 More preferably, 0.15 cm or less. 2 More than 15cm 2 Less than 0.2 cm, more preferably 2 More than 10cm 2 The following is the result.

[0014] The resin constituting each resin layer of the resin laminate may be one type of resin or multiple types of resins.

[0015] 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.

[0016] There is no particular limitation on the components of the resins constituting the first resin layer 10, the second resin layer 30, and the third resin layer 60. Examples of the resin components include polyethylene (PE), polyethylene terephthalate (PET), polyamide (PA), and the like.

[0017] 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.

[0018] The first resin layer 10, the second resin layer 30, and the third resin layer 60 may be mono-material in which the same type of resin is used for all the resin layers. 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.

[0019] 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 same type of resin may have different physical properties for each resin layer. 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.

[0020] The thickness of each of the first resin layer 10, the second resin layer 30, and the third resin layer 60 is not particularly limited. 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.

[0021] 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 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 via the second adhesive layer 40.

[0022] There is no particular limitation on the type of adhesive constituting the first adhesive layer 20 and the second adhesive layer 40. Examples of the types of adhesive include two-component curing urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, and epoxy adhesives. Molten resins such as polyethylene can also be used as adhesives.

[0023] 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.

[0024] The resin laminate 100 may further include a printed layer, a barrier layer, an anchor coat layer, a functional layer, a surface coat layer, and the like.

[0025] In the resin laminate 100, for example, the printed layer 50 is formed by printing and applying an ink material to the surface of the third resin layer 60 on the second resin layer 30 side. This makes the printed layer visible from the third resin layer 60 side of the resin laminate 100, as shown in Fig. 2. The printed layer can contain one or more types of ordinary ink vehicles as a main component.

[0026] The printing layer may further contain one or more additives, such as a plasticizer, a stabilizer, an antioxidant, a light stabilizer, an ultraviolet absorber, a curing agent, a crosslinking agent, a lubricant, an antistatic agent, a filler, etc. The printing layer may be formed from an ink composition prepared by adding a colorant, such as a dye or pigment, and thoroughly kneading with a solvent, a diluent, etc.

[0027] Furthermore, the ink composition can be used to form desired printed patterns consisting of letters, figures, symbols, designs, etc., by using printing methods such as gravure printing, offset printing, letterpress printing, screen printing, transfer printing, and flexographic printing.

[0028] In addition, 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 in which a metal or metal oxide is vapor-deposited.

[0029] As the vapor-deposited film, a polyethylene terephthalate film having a vapor-deposited layer of a metal such as aluminum or an inorganic vapor-deposited layer such as alumina or silica, or a polypropylene film having a vapor-deposited layer of a metal such as aluminum or an inorganic vapor-deposited layer such as alumina or silica can be used.

[0030] The metal foil may be an aluminum foil or the like, and the thickness of the foil may be from 5 μm to 20 μm.

[0031] The method for peeling a laminate according to the present disclosure includes a slit forming step and a dipping step.

[0032] In the slit forming step, a slit S is formed in the resin laminate 100. In this specification, a slit refers to a linear cut that penetrates the resin laminate.

[0033] The mode of forming the slits S is not particularly limited, and for example, the slits S are formed in the resin laminate 100 by making cuts in the thickness direction of the resin laminate 100 with a metal blade. Note that when forming the slits S, it is preferable not to cut out a part of the resin laminate 100 in order to avoid generating excess waste.

[0034] The shape of the slit S is not particularly limited and may be any of a straight line, a curved line, and a combination of a straight line and a curved line, but is preferably a straight line.

[0035] The width of the slit S 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, and more preferably 0.1 mm or less.

[0036] The direction of the slits S is not particularly limited. For example, as shown in Fig. 1, in one example of the resin laminate, a square resin laminate 100 is formed with slits S extending parallel to sides 1 and 3 that face each other in the lateral direction (X direction) of the square. Also, as shown in Fig. 4, in a first modified example of the resin laminate, a square resin laminate 100 is formed with slits S extending obliquely to each side (side 1, side 2, side 3, and side 4) of the square.

[0037] There is no particular limitation on the length of the slit S. For example, as shown in Fig. 1, in one example of the resin laminate, when the length of each side (side 1, side 2, side 3, or side 4) of a square resin laminate 100 is taken as 100%, the length of the slit S is 20% or more, preferably 40% or more, and more preferably 60% or more.

[0038] The number of slits S is not limited to 1, and may be 2 or more. For example, as shown in Fig. 5 to Fig. 8, in the second, third, fourth, and fifth modified examples of the resin laminate 100, the slits S are configured with three slits (slits S1, S2, and S3).

[0039] When two or more slits S are formed in the resin laminate 100, the arrangement of each slit is not limited. For example, each slit may be arranged so that two or more slits S are aligned in parallel. As shown in Fig. 5, in the second modified example of the resin laminate, three slits S (slits S1, S2, and S3) extending in the vertical direction (Y direction) of the resin laminate 100 are arranged at equal intervals in the horizontal direction (X direction) of the resin laminate 100.

[0040] As shown in Fig. 5, in the second modified example of the resin laminate, three slits S (slits S1, S2, and S3) are arranged in the center of the resin laminate 100, but are not limited to such an arrangement. For example, as shown in Fig. 6, in the third modified example of the resin laminate, three slits S (slits S1, S2, and S3) may be arranged biased to one side of each side of the resin laminate 100 (for example, side 3).

[0041] Furthermore, as shown in FIG. 7, in a fourth modified example of the resin laminate, slits S extending diagonally to each side (side 1, side 2, side 3, and side 4) of the square resin laminate 100 are arranged in parallel.

[0042] When two or more slits S are formed in the resin laminate 100, the lengths of the slits may be the same or different. In addition, the slits are not limited to being arranged in parallel as described above, and may be arranged randomly. For example, as shown in FIG. 8, in a fifth modified example of the resin laminate, three slits S (slit S1, slit S2, and slit S3) having different lengths are arranged randomly in the resin laminate 100.

[0043] Furthermore, when two or more slits S are formed in the resin laminate 100, the slits may be arranged so that the two or more slits intersect. For example, as shown in Fig. 9, in a sixth modified example of the resin laminate, a slit S (slit S4) extending in the vertical direction (Y direction) of the resin laminate 100 and a slit S (slit S5) extending in the horizontal direction (X direction) of the resin laminate 100 are arranged so as to intersect at right angles at the center of the resin laminate 100.

[0044] Furthermore, as shown in FIG. 10, in the seventh modified example of the resin laminate, two slits S (slits S4 and S5) extending diagonally to each side (side 1, side 2, side 3, and side 4) of the square resin laminate 100 are arranged so as to intersect at right angles in the center of the resin laminate 100.

[0045] Furthermore, as shown in Figure 11, in the eighth modified example of the resin laminate, in addition to the two slits S (slit S4 and slit S5) in the seventh modified example of Figure 10, a slit S (slit S6) extending in the vertical direction (Y direction) of the resin laminate 100 is arranged so as to intersect at the center of the resin laminate 100.

[0046] Furthermore, when two or more slits S are formed in the resin laminate 100, the two or more slits may be configured as a first slit group having multiple slits arranged parallel to a first direction, and a second slit group having multiple slits arranged parallel to the first direction and facing the first slit group in a second direction perpendicular to the first direction.

[0047] For example, as shown in FIG. 12, in the ninth modified example of the resin laminate, three slits S1 (slits S11, S12, and S13) arranged at equal intervals in the horizontal direction (X direction) of the resin laminate 100 and extending in the vertical direction (Y direction) of the resin laminate 100 are arranged on one side 2 of the vertical direction (Y direction) of the resin laminate 100. In addition, three slits S2 (slits S21, S22, and S23) arranged at equal intervals in the horizontal direction (X direction) of the resin laminate 100 and extending in the vertical direction (Y direction) of the resin laminate 100 are arranged on the other side 4 of the vertical direction (Y direction) of the resin laminate 100. Furthermore, the three slits S1 and the three slits S2 are arranged opposite to each other in the vertical direction (Y direction) of the resin laminate 100. Here, the three slits S1 and the three slits S2 are an example of the first slit group and the second slit group of the present disclosure. Moreover, the longitudinal direction (Y direction) and longitudinal direction (Y direction) of the resin laminate 100 are examples of the first direction and second direction of the present disclosure.

[0048] It is preferable that the slits S are formed continuously from the edge of the resin laminate 100, regardless of the number of slits S formed in the resin laminate 100. For example, as shown in Fig. 13, in the tenth modified example of the resin laminate, the three slits S1 (slits S11, S12, and S13) arranged on one side 2 in the ninth modified example of Fig. 12 are formed continuously on the one side 2. In addition, the three slits S2 (slits S21, S22, and S23) arranged on the other side 4 are formed continuously on the other side 4. Here, the one side 2 and the other side 4 are both examples of the edge of the resin laminate of the present disclosure.

[0049] In addition, when two or more slits are formed in the resin laminate, the two or more slits may be arranged in a staggered manner. For example, as shown in Fig. 14, in the eleventh modified example of the resin laminate, two slits S1 (slits S11 and S12) are arranged in the horizontal direction (X direction) of the resin laminate 100, and extend in the vertical direction (Y direction) of the resin laminate 100, continuing from one side 2 in the vertical direction (Y direction) of the resin laminate 100, and two slits S2 (slits S21 and S22) are arranged in the horizontal direction (X direction) of the resin laminate 100, and extend in the vertical direction (Y direction) of the resin laminate 100, continuing from the other side 4 in the vertical direction (Y direction) of the resin laminate 100, and one slit S3 is arranged in the center of the resin laminate 100 in a staggered manner with respect to the two slits S1 and the two slits S2.

[0050] In the laminate peeling method of the present disclosure, in the immersion step, the resin laminate 100 having the slit S formed therein is immersed in a stripping liquid. The manner in which the resin laminate 100 is immersed in the stripping liquid is not particularly limited. In the present disclosure, for example, as shown in FIG. 15, the resin laminate 100 is immersed in a stripping liquid 80 contained in an immersion bath 70.

[0051] The components of the stripping solution are not particularly limited, and examples thereof include an inorganic solvent, an inorganic solution, an organic solvent, an organic solution, a mixture of an inorganic compound and an organic solvent, a mixture of an inorganic compound and an organic solution, a mixture of an inorganic solvent and an organic solvent, a mixture of an inorganic solvent and an organic solution, a mixture of an inorganic solution and an organic solvent, a mixture of an inorganic solution and an organic solution, etc. Among these, a mixture of an inorganic compound and an organic solvent and a mixture of an inorganic compound and an organic solution are preferred.

[0052] The mixture of an inorganic compound and an organic solvent is, for example, a mixture of an alkaline inorganic compound and an alcohol, preferably a mixture of potassium hydroxide and methanol, or a mixture of sodium hydroxide and methanol.

[0053] The mixture of an inorganic compound and an organic solution is, for example, a mixture of an alkaline inorganic compound and an alcohol solution, preferably a mixture of potassium hydroxide, methanol, and N-methyl-2-pyrrolidone (NMP). From the viewpoint of reducing the toxicity of the stripping solution, a stripping solution that does not contain NMP (such as a mixture of potassium hydroxide and methanol, or a mixture of sodium hydroxide and methanol) is preferable.

[0054] The temperature of the stripping solution is not particularly limited and 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.

[0055] In the immersion step, a physical treatment such as stirring the stripping solution or applying ultrasonic vibration to the stripping solution may be added as desired.

[0056] As described above, the laminate peeling method of the present disclosure includes a slit forming step and an immersion step, and when the resin laminate 100 with the slit S formed therein is immersed in the peeling liquid 80, the peeling liquid 80 penetrates between the resin layers of the resin laminate 100 not only from the edge of the resin laminate 100 but also from the portion where the slit S is formed. Therefore, as shown in Figs. 15 and 16, the first resin layer 10, the second resin layer 30, and the third resin layer 60 are easily peeled from the resin laminate 100. Thus, according to the laminate peeling method of the present disclosure, each resin can be separated (isolated) from the resin laminate without using large-scale equipment (stirring, ultrasonic vibration, etc.).

[0057] Furthermore, in the laminate peeling method of the present disclosure, by forming a slit S in the resin laminate 100, the end of the slit S can be formed at a position close to the edge of the resin laminate 100. Therefore, the stripping liquid 80 can easily penetrate between the end of the slit S and the edge of the resin laminate 100. This makes it possible to shorten the time from when the resin laminate is immersed in the stripping liquid until each resin layer is peeled off. In this way, according to the laminate peeling method of the present disclosure, each resin can be efficiently separated (isolated) from the resin laminate.

[0058] Furthermore, in the laminate peeling method of the present disclosure, as described above, the peeling liquid 80 can easily penetrate between the resin layers of the resin laminate 100 through the slit S, so that even if the bonds between the resin layers are strong, each resin layer can be isolated. Therefore, regardless of whether the resin laminate is a composite material or a mono-material, each resin can be separated (isolated) from the resin laminate.

[0059] Furthermore, according to the laminate peeling method of the present disclosure, as described above, each resin can be isolated from the resin laminate 100, making it easy to separate the resins. This makes it possible to reuse each resin constituting the resin laminate 100.

[0060] In the laminate peeling method of the present disclosure, as described above, when there are two or more slits S, the portion into which the stripping liquid 80 penetrates increases in the resin laminate 100, and the time from when the resin laminate is immersed in the stripping liquid until each resin layer is peeled off can be further shortened. Therefore, according to the laminate peeling method of the present disclosure, each resin can be separated (isolated) from the resin laminate more efficiently.

[0061] In the laminate peeling method disclosed herein, as described above, by arranging two or more slits in parallel, even when two or more slits are formed regularly, the effect of shortening the time from immersing the resin laminate in the peeling solution to peeling off each resin layer can be maintained.

[0062] In the laminate peeling method disclosed herein, as described above, by intersecting two or more slits, the effect of shortening the time from immersing the resin laminate in the peeling solution to peeling off each resin layer can be maintained, even if another slit is formed in a part of the resin laminate where a slit has already been formed.

[0063] In the laminate peeling method disclosed herein, as described above, by configuring two or more slits as a first slit group having a plurality of slits aligned parallel to a first direction, and a second slit group having a plurality of slits aligned parallel to the first direction and facing the first slit group in a second direction perpendicular to the first direction, the area through which the stripping liquid 80 penetrates in the resin laminate 100 is further increased, thereby further shortening the time from immersing the resin laminate in the stripping liquid until each resin layer is peeled off.

[0064] In the laminate peeling method of the present disclosure, as described above, the slit is formed continuously from the edge of the resin laminate, so that the stripping liquid 80 can easily enter the slit S by capillary action. This further increases the amount of the stripping liquid 80 that permeates between the resin layers of the resin laminate 100, so that the stripping liquid 80 can more easily permeate between the resin layers of the resin laminate 100. This enables more efficient separation (isolation) of each resin from the resin laminate.

[0065] In the method for peeling off a laminate according to the present disclosure, as described above, the area of ​​the resin laminate 100 is 0.1 cm 2 More than 20cm 2 If the thickness is less than this, the operation of forming slits in the resin laminate in the slit forming step is facilitated, the operation of immersing the resin laminate in the stripping solution is facilitated in the immersion step, and further, separation (isolation) of each resin peeled (separated) from the resin laminate in the immersion step is facilitated.

[0066] In the method for peeling off a laminate of the present disclosure, as described above, the peeling liquid 80 is a mixed liquid of an alkaline inorganic compound and an alcohol, so that even if layers other than resin, such as an adhesive layer or a metal deposition layer, exist between the resin layers constituting the resin laminate, these layers other than resin are easily dissolved. Therefore, the bond between the resin layers due to adhesion can be easily dissolved, and each resin can be easily separated (isolated) from the resin laminate.

[0067] In addition, since the stripping solution is a mixture of an alkaline inorganic compound and an alcohol, even if a colored layer containing ink or pigment, such as a printed layer, is present between the resin layers that make up the resin laminate, the colored layer is easily dissolved. This makes it possible to remove (deink) the ink or pigment from the attached layer when each resin layer is peeled off from the resin laminate, and therefore each resin can be cleanly (recyclably) separated (isolated) from the resin laminate.

[0068] In the method for peeling a laminate of the present disclosure, as described above, by setting the temperature of the peeling solution 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. In addition, by setting the temperature of the peeling solution to 40° C. or higher and 80° C. or lower, the rate of dissolving layers other than the resin present between the resin layers constituting the resin laminate (adhesive layer, metal deposition layer, colored layer, etc.) can be increased. Therefore, the time from immersing the resin laminate in the peeling solution until each resin layer is peeled off can be further shortened, which enables more efficient separation (isolation) of each resin from the resin laminate.

[0069] In the laminate peeling method of the present disclosure, as described above, each resin can be separated (isolated) from the resin laminate without adding physical treatments such as stirring or ultrasonic vibration. However, by adding such physical treatments, some of the resin layers of the resin laminate 100 (e.g., the above-mentioned PET layer) or the adhesive layer between the resin layers can be dissolved more efficiently. EXAMPLES

[0070] The present invention will now be described in more detail with reference to examples. The examples and comparative examples were evaluated by the following tests.

[0071] [Resin laminate (test specimen)] As test specimens, a square laminate CM (composite material) and a square laminate MM (three-layer mono-material) were prepared. The laminate CM is a three-layer composite material with a polyamide (PA) resin layer / printed layer of 15 μm, an adhesive layer of 2 μm, an aluminum vapor deposition layer / polyethylene terephthalate (PET) resin layer of 12 μm, an adhesive layer of 2 μm, and a linear low-density polyethylene (LLDPE) resin layer of 100 μm. The adhesive is a urethane cured material. The laminate MM is a three-layer mono-material with a high-density polyethylene (HDPE) resin layer of 25 μm, an adhesive layer of 2 μm, a linear low-density polyethylene (LLDPE) resin layer of 25 μm, an adhesive layer of 2 μm, and a linear low-density polyethylene (LLDPE) resin layer of 80 μm. Linear slits were formed in the laminate CM and the laminate MM.

[0072] [Stripper] Solution 1, Solution 2, and Solution 3 were prepared as stripping solutions for immersing the test specimens. Solution 1 is a mixture of potassium hydroxide (KOH) and methanol (MeOH). Solution 2 is a mixture of sodium hydroxide (NaOH) and methanol (MeOH). Solution 3 is a mixture of potassium hydroxide (KOH), methanol (MeOH), methanol, and N-methyl-2-pyrrolidone (NMP).

[0073] [Immersion test] The resin laminate (test specimen) was immersed in the stripping solution, and it was confirmed whether each resin layer peeled off naturally without using tweezers etc. The peeling test was evaluated (judged) according to the following criteria. Good: Separated into 3 layers within 120 minutes Poor: Could not separate into layers within 120 minutes

[0074] Examples and comparative examples are listed below.

[0075] [Example 1] A laminate CM (see Figs. 1 to 3) having a size of 10 mm x 10 mm, one slit with a length of 7 mm, and the slit located in the center of the laminate was immersed in solution 1 at 60°C as a stripping solution, and the releasability was evaluated based on the time it took for each resin layer to peel off. The conditions and results (evaluation) of Example 1 are shown in Table 1.

[0076] [Example 2] The number of slits was three, and each slit was arranged parallel to the side of the specimen at equal intervals (see FIG. 5), and otherwise the specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 2 are shown in Table 1.

[0077] [Example 3] The number of slits was set to 5, and otherwise a test specimen was prepared and evaluated in the same manner as in Example 2. The conditions and results (evaluation) of Example 3 are shown in Table 1.

[0078] [Example 4] The size of the test specimen was 30 mm × 30 mm, the number of slits was 5, and the length of the slits was 21 mm, and other than that, the test specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 4 are shown in Table 1.

[0079] [Example 5] The stripping solution in which the test specimen was immersed was stirred, and otherwise the test specimen was prepared and evaluated in the same manner as in Example 4. The conditions and results (evaluation) of Example 5 are shown in Table 1.

[0080] [Example 6] The size of the test specimen was 5 mm×5 mm, the length of the slit was 3 mm, and otherwise the test specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 6 are shown in Table 1.

[0081] [Example 7] The number of slits was three, and each slit was arranged parallel to the side of the test piece at equal intervals, and otherwise the test piece was produced and evaluated in the same manner as in Example 6. The conditions and results (evaluation) of Example 7 are shown in Table 1.

[0082] [Example 8] The number of slits was set to 5, and otherwise a test specimen was prepared and evaluated in the same manner as in Example 7. The conditions and results (evaluation) of Example 8 are shown in Table 1.

[0083] [Example 9] A test specimen was prepared and evaluated in the same manner as in Example 2, except that the stripping liquid was Solution 2. The conditions and results (evaluation) of Example 9 are shown in Table 1.

[0084] [Example 10] A test specimen was prepared and evaluated in the same manner as in Example 4, except that the stripping liquid was Solution 2. The conditions and results (evaluation) of Example 10 are shown in Table 1.

[0085] [Example 11] A test specimen was prepared and evaluated in the same manner as in Example 2, except that the stripping solution was Solution 3. The conditions and results (evaluation) of Example 11 are shown in Table 1.

[0086] [Example 12] The number of slits was two, and each slit was arranged diagonally with respect to the sides of the specimen and perpendicularly at the center of the specimen (intersection 1, see FIG. 10). Except for this, the specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 12 are shown in Table 1.

[0087] [Example 13] The number of slits was two, each slit was arranged parallel to the side of the specimen and perpendicular to the center of the specimen (intersection 2, see Figure 9), and otherwise the specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 13 are shown in Table 1.

[0088] [Example 14] The number of slits was three, two slits were arranged diagonally to the side of the test specimen and perpendicular to the center of the test specimen (intersection 3, see Figure 11), and the remaining one was parallel to the side of the test specimen and intersected with the two perpendicular slits at the center of the test specimen, and the rest was similar to Example 12, and the test specimen was prepared and evaluated. The conditions and results (evaluation) of Example 14 are shown in Table 1.

[0089] [Example 15] The two slits were arranged biased toward one side of the test specimen (see FIG. 6), and otherwise the test specimen was prepared and evaluated in the same manner as in Example 2. The conditions and results (evaluation) of Example 15 are shown in Table 1.

[0090] [Example 16] The slits were arranged diagonally with respect to the sides of the specimen (diagonal 1, see FIG. 4), and otherwise the specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 16 are shown in Table 1.

[0091] [Example 17] The number of slits was three, and each slit was arranged diagonally and at equal intervals with respect to the side of the test specimen (diagonal 2, see FIG. 7), and otherwise the test specimen was prepared and evaluated in the same manner as in Example 16. The conditions and results (evaluation) of Example 17 are shown in Table 1.

[0092] [Example 18] Slits of different lengths were randomly arranged (diagonal 3, see FIG. 8), and otherwise test specimens were prepared and evaluated in the same manner as in Example 17. The conditions and results (evaluation) of Example 18 are shown in Table 1.

[0093] [Example 19] The length of the slit was set to 3 mm, and otherwise a test specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 19 are shown in Table 1.

[0094] [Example 20] The length of the slit was set to 2 mm, and otherwise a test specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 19 are shown in Table 1.

[0095] [Example 21] The number of slits was six, the length of the slits was 3.5 mm, three slits were arranged at equal intervals in the horizontal direction of the test specimen and extending in the vertical direction of the test specimen were arranged on one vertical side of the test specimen, and the remaining three slits were arranged at equal intervals in the horizontal direction of the test specimen and extending in the vertical direction of the test specimen were arranged on the other vertical side of the test specimen (two slits in one row, see Figure 12), and the rest of the test specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 21 are shown in Table 1.

[0096] [Example 22] The number of slits was 5, the length of slits was 3.5 mm for 4, and 7 mm for 1. Two slits extending vertically of the specimen at equal intervals in the horizontal direction were arranged continuously with one vertical side of the specimen, and the remaining two slits extending vertically of the specimen at equal intervals in the horizontal direction were arranged continuously with the other vertical side of the specimen, and the remaining one slit was arranged in the center of the specimen in a staggered manner with respect to the two slits continuing with one side and the two slits S2 continuing with the other side (end cut 1, see FIG. 14). Except for this, the specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (judgment) of Example 22 are shown in Table 1.

[0097] [Example 23] The three slits on one side of the test specimen in the vertical direction were arranged continuously with that side, and the three slits on the other side of the test specimen in the vertical direction were arranged continuously with that other side (end notch 2, see FIG. 13), and otherwise the test specimen was prepared and evaluated in the same manner as in Example 21. The conditions and results (evaluation) of Example 23 are shown in Table 1.

[0098] [Example 24] The laminate MM was used as a test specimen, and other than that, a test specimen was prepared and evaluated in the same manner as in Example 2. The conditions and results (evaluation) of Example 24 are shown in Table 2.

[0099] [Example 25] The laminate MM was used as a test specimen, and other than that, a test specimen was prepared and evaluated in the same manner as in Example 6. The conditions and results (evaluation) of Example 25 are shown in Table 2.

[0100] [Example 26] A laminate (test specimen) was prepared and evaluated in the same manner as in Example 7, except that laminate MM was used as the laminate (test specimen). The conditions and results (evaluation) of Example 26 are shown in Table 2.

[0101] [Example 27] The temperature of the stripping solution in which the test specimen was immersed was set to 23° C., and otherwise the test specimen was prepared and evaluated in the same manner as in Example 1. The conditions and results (evaluation) of Example 27 are shown in Table 3.

[0102] [Example 28] The temperature of the stripping solution in which the test specimen was immersed was set to 23° C., and otherwise the test specimen was prepared and evaluated in the same manner as in Example 2. The conditions and results (evaluation) of Example 28 are shown in Table 3.

[0103] [Comparative Example 1] Except for the fact that no slits were formed in the test specimen, the evaluation was performed under the same conditions as in Example 1. The conditions and results of Comparative Example 1 are shown in Table 1.

[0104] [Comparative Example 2] Except for the fact that no slits were formed in the test specimen, the evaluation was performed under the same conditions as in Example 25. The conditions and results of Comparative Example 2 are shown in Table 2.

[0105] [Comparative Example 3] Except for the fact that no slits were formed in the test specimen, the evaluation was performed under the same conditions as in Example 27. The conditions and results of Comparative Example 3 are shown in Table 3.

[0106] [Table 1]

[0107] [Table 2]

[0108] [Table 3]

[0109] From Tables 1 and 2, it was found that in Examples 1 to 26, when a test specimen (resin laminate) with a slit formed therein was immersed in a stripping solution, each resin layer could be separated (isolated) from the resin laminate within 120 minutes in all cases.

[0110] Furthermore, from Table 2, it was found that in Examples 24 to 26, even in the case of the monomaterial, which tends to be relatively more difficult to peel off than the composite material, each resin layer could be separated (isolated) from the resin laminate in the same manner as in the composite material.

[0111] On the other hand, in Comparative Examples 1 and 2, when a resin laminate (test specimen) in which no slits were formed was immersed in the stripping solution, each resin could not be separated (isolated) from the resin laminate even after 120 minutes had passed.

[0112] Furthermore, from Table 3, it was found that in Examples 27 and 28, each resin layer could be separated (isolated) from the resin laminate within 24 hours even when the temperature of the stripping solution was 23° C. On the other hand, in Comparative Example 3, when the temperature of the stripping solution was 23° C., each resin could not be separated (isolated) from the resin laminate even after 33 hours had passed.

[0113] The embodiments of the present disclosure are further described as follows.

[0114] <1> A method for peeling a resin layer from a resin laminate having a plurality of resin layers laminated thereon, comprising the steps of: forming slits in the resin laminate; and immersing the resin laminate in which the slits are formed in a stripping liquid. A method for peeling off a laminate.

[0115] <2> The slits are two or more. <1> 2. A method for peeling off a laminate according to claim 1.

[0116] <3> The two or more slits are arranged in parallel. <2> 2. A method for peeling off a laminate according to claim 1.

[0117] <4> The two or more slits intersect with each other. <2> 2. A method for peeling off a laminate according to claim 1.

[0118] <5> The two or more slits are a first slit group including a plurality of slits arranged parallel to a first direction; a second slit group in which a plurality of slits are arranged parallel to a first direction and opposed to the first slit group in a second direction perpendicular to the first direction; <2> 2. A method for peeling off a laminate according to claim 1.

[0119] <6> The slit is formed continuously from an edge of the resin laminate. <1> ~ <5> 2. A method for peeling off a laminate according to claim 1.

[0120] <7> The area of ​​the resin laminate is 0.1 cm 2 More than 20cm 2 The above is <1> ~ <6> 13. The method for peeling off a laminate according to any one of claims 1 to 12.

[0121] <8> The stripping solution is a mixture of an alkaline inorganic compound and an alcohol. <1> ~ <7> 13. The method for peeling off a laminate according to any one of claims 1 to 12.

[0122] <9> The temperature of the stripping solution is 20° C. or higher. <1> ~ <8> 13. The method for peeling off a laminate according to any one of claims 1 to 12.

[0123] 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]

[0124] 100 Resin laminate Sides 1, 2, 3, 4 S, S1, S2, S3, S4, S5, S6, S11, S12, S13, S21, S22, S23 Slit 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 Stripping solution

Claims

1. A method for peeling a resin layer from a resin laminate having a plurality of resin layers laminated thereon, comprising the steps of: forming slits in the resin laminate; and immersing the resin laminate in which the slits are formed in a stripping liquid. A method for peeling off a laminate.

2. The slits are two or more. The method for peeling the laminate according to claim 1 .

3. The two or more slits are arranged in parallel. The method for peeling off the laminate according to claim 2 .

4. The two or more slits intersect. The method for peeling off the laminate according to claim 2 .

5. The two or more slits are a first slit group including a plurality of slits arranged parallel to a first direction; A second slit group, in which a plurality of slits are arranged parallel to a first direction and opposed to the first slit group in a second direction perpendicular to the first direction, The method for peeling off the laminate according to claim 2 .

6. The slit is formed continuously from an edge of the resin laminate. The method for peeling the laminate according to claim 1 .

7. The area of ​​the resin laminate is 0.1 cm ２ 20cm or more ２ Below is the The method for peeling off the laminate according to any one of claims 1 to 6.

8. The stripping solution is a mixture of an alkaline inorganic compound and an alcohol. The method for peeling off the laminate according to any one of claims 1 to 6.

9. The temperature of the stripping solution is 20° C. or higher. The method for peeling off the laminate according to any one of claims 1 to 6.

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