Method for removing coating layer and device for removing coating layer

Abstract

This method for removing a coating layer comprises: a step for feeding a laminated film (90) from a laminated film roll; a step for blowing a gas to the laminated film (90), which is being wound around a backup roller (20) and conveyed, toward both end sides in the width direction of the laminated film so as to blow off water adhering to said both end sides of the laminated film toward the outer side of a first end side and the outer side of a second end side, opposite to the first end side, in the axial direction of the backup roller (20); a removal step for removing a coating layer by jetting pressurized water (W2) when the laminated film (90) passes through the backup roller (20); and a base material recovery step for winding and recovering a base material film (91). The blowing step is performed on the upstream side and / or the downstream side from the position where the pressurized water (W2) is jetted.

Description

Method for Removing Coating Layer and Coating Layer Removal Device

[0001] The present invention relates to a method for removing a coating layer and a coating layer removal device.

[0002] In recent years, from the viewpoints of global resource protection and environmental protection, etc., in various fields, efforts such as suppressing the generation of waste, reusing, and recycling are being actively carried out to aim at building a recycling-based society. For example, Patent Document 1 discloses a method for recycling a plastic product having a coating film, which comprises peeling a coating film formed on a plastic body from the plastic body with high-pressure jet water and crushing and recycling the plastic body. Patent Document 2 discloses a method for removing a coating layer from a laminated film, which comprises a step of preparing a roll around which a laminated film having a base material film and a coating layer is wound, a step of feeding out the laminated film from the roll, a step of stretching the fed-out laminated film, a step of removing the coating layer from the laminated film by immersing the stretched laminated film in warm water in a water tank, and a step of winding up the base material film from which the coating layer has been removed in a roll shape, wherein the coating layer includes an intermediate layer and a release agent layer, and the intermediate layer is disposed between the base material film and the release agent layer.

[0003] Japanese Patent Application Laid-Open No. H05-269743 Japanese Patent Application Laid-Open No. 2023-148862

[0004] In the technology of removing a coating layer from a laminated film in a roll-to-roll manner, it is required to improve the removal efficiency of the coating layer. In the method described in Patent Document 1, the coating film can be peeled from the plastic body by blowing high-pressure jet water onto the coating film surface. However, the method described in Patent Document 1 is not a technology that employs roll-to-roll. In the method described in Patent Document 2, the coating layer can be removed from the laminated film by immersing the laminated film in warm water in a roll-to-roll manner. However, since the configuration of the coating layer is diverse, the method described in Patent Document 2 has room for further improvement in terms of improving the removal efficiency.

[0005] The object of the present invention is to provide a method and apparatus for removing a coating layer that can improve the efficiency of removing the coating layer in a roll-to-roll technique for removing a coating layer from a laminated film.

[0006] [1] A method for removing a coating layer, comprising the steps of: preparing a laminated film roll around which a laminated film having a base film and a coating layer is wound; unwinding the laminated film from the laminated film roll; blowing gas toward both ends of the laminated film, which is being conveyed wound around a backup roller, so as to blow away water adhering to both ends of the laminated film in the width direction toward the outside of the first end and the second end opposite to the first end in the axial direction of the backup roller; removing the coating layer by spraying pressurized water onto the coating layer of the laminated film as the laminated film passes the backup roller; and recovering the base film after the coating layer has been removed by winding it into a roll, wherein the spraying step is performed at least on one side upstream and downstream of the position where the pressurized water is sprayed. [2] The method for removing a coating layer according to [1], wherein the spraying step comprises a first spraying step performed upstream of the position from which the pressurized water is sprayed and a second spraying step performed downstream of the position from which the pressurized water is sprayed, and the preparation step, the dispensing step, the first spraying step, the removal step, the second spraying step, and the substrate recovery step are performed in this order. [3] The method for removing a coating layer according to [1] or [2], wherein the spraying step is a step of pressing both ends in the width direction of the laminated film against the backup roller by spraying gas so that the pressurized water does not penetrate from both ends in the width direction of the laminated film to the interface between the laminated film and the backup roller. [4] The method for removing a coating layer according to any one of [1] to [3], further comprising a step of filtering the water containing the coating layer removed in the removal step and circulating it to a pump. [5] A method for removing a coating layer according to any one of [1] to [4], further comprising a step of draining the water from the substrate film after the removal step and before the substrate recovery step.[6] The method for removing a coating layer according to any one of [1] to [5], wherein the coating layer includes a release agent layer. [7] The method for removing a coating layer according to [6], wherein the coating layer includes a ceramic green sheet. [8] A coating layer removal apparatus for removing a coating layer from a laminated film having a base film and a coating layer, comprising: a feed shaft for feeding the laminated film from a laminated film roll in which the laminated film is wound in a roll shape; a backup roller disposed downstream of the feed shaft for winding the laminated film and transporting it downstream; a spray unit including one or more liquid nozzles disposed opposite the backup roller for spraying water onto the coating layer from the one or more liquid nozzles so as the laminated film passes the backup roller to remove the coating layer; one or more gas nozzles disposed at least one upstream and one downstream of the spray unit for blowing gas onto the laminated film wound on the backup roller; a pressurized water supply unit for pressurizing water and supplying pressurized water to the spray unit; one or more gas supply units for pressurizing gas and supplying gas to the one or more gas nozzles; and a winding shaft for winding the base film in a roll shape after the coating layer has been removed, wherein the pressurized water supply unit includes a pump, and the spray unit is connected to the pump. A coating layer removal device wherein the one or more gas nozzles have a plurality of gas nozzle openings, and the plurality of gas nozzle openings are arranged facing the first end side or the second end side in the axial direction of the backup roller so as to blow away water adhering to both ends of the laminated film in the width direction to the outside of the first end side in the axial direction of the backup roller and to the outside of the second end side opposite to the first end side. [9] The coating layer removal device according to [8] wherein the one or more gas nozzles are arranged both upstream and downstream of the injection section.

[0007] According to one aspect of the present invention, a method for removing a coating layer and an apparatus for removing a coating layer can be provided that can improve the efficiency of removing the coating layer in a roll-to-roll technique for removing a coating layer from a laminated film.

[0008] A cross-sectional view of a first example of a laminated film used in the removal method according to the first embodiment. A perspective view of a second example of a laminated film used in the removal method according to the first embodiment. A schematic diagram of an example of a removal apparatus according to the second embodiment. A diagram illustrating the spraying process of the removal method according to the first embodiment.

[0009] In this specification, ordinal numbers such as "first" and "second" are used to distinguish components and do not indicate order. In this specification, expressions without ordinal numbers, such as "gas nozzle," are a general term for gas nozzles and are used when describing nozzles that have ordinal numbers such as "first" and "second." For example, when a description is made that applies to multiple components that are indicated with ordinal numbers, such as "first gas nozzle" and "second gas nozzle," the "first gas nozzle" and "second gas nozzle" are expressed collectively by omitting the ordinal number and simply using "gas nozzle."

[0010] [First Embodiment] [Method for Removing the Coating Layer] The method for removing the coating layer according to this embodiment includes the steps of: preparing a laminated film roll around which a laminated film having a base film and a coating layer is wound; unwinding the laminated film from the laminated film roll; blowing gas toward both ends in the width direction of the laminated film so as the laminated film is wound around a backup roller and transported, blowing away water adhering to both ends in the width direction of the laminated film toward the outside of the first end and the second end opposite to the first end in the axial direction of the backup roller; removing the coating layer by spraying pressurized water onto the coating layer of the laminated film as the laminated film passes through the backup roller; and recovering the base film after the coating layer has been removed by winding it into a roll. The spraying step is performed at least on one side upstream and downstream of the position where the pressurized water is sprayed. The removal method according to this embodiment is performed roll-to-roll. Here, in the section describing the "spraying step" after the removal step, "laminated film" can be read as "base film". For example, "blow gas toward both ends in the width direction of the laminated film" can be rephrased as "blow gas toward both ends in the width direction of the base film."

[0011] In this embodiment, when removing the coating layer from a laminated film using the impact pressure of water in a roll-to-roll manner, it is necessary to spray pressurized water onto the coating layer while the side of the laminated film opposite to the coating layer (hereinafter also referred to as the back surface of the laminated film) is in close contact with the backup roller. However, as the laminated film is transported, the pressurized water sprayed onto it may form droplets that float on the film surface and flow towards the edge of the backup roller, and then, as the backup roller rotates, may float back inward from the edge of the backup roller. The water that moves inward to the backup roller becomes trapped between the back surface of the laminated film and the backup roller. When pressurized water is trapped between the backup roller and the laminated film, the impact force when the pressurized water collides with the coating layer is mitigated, resulting in a decrease in the efficiency of coating layer removal. Therefore, in the removal method according to this embodiment, gas is sprayed towards both ends in the width direction of the laminated film at at least one position upstream and downstream of the position where the pressurized water is sprayed (the spraying step). The spraying step will be specifically explained using Figures 1 and 4. The following description will explain the case in which the spraying process is carried out using a pair of gas nozzles (an example of a means for spraying gas). Figure 1 is a cross-sectional view of a first example of a laminated film used in the removal method according to the first embodiment. The laminated film 90 has a base film 91 and a coating layer 92. The base film 91 has a first base surface 91a and a second base surface 91b opposite to the first base surface 91a. The base film 91 and the coating layer 92 are directly laminated. Figure 4 is a diagram for explaining the spraying process and is a perspective view of the backup roller and guide rollers GR1 and GR2 viewed from the upstream side. The laminated film 90 is wound and conveyed in the order of the first guide roller GR1, the backup roller 20, and the second guide roller GR2. The backup roller 20 has a central axis 20a and has a first end 21 in the axial direction and a second end 22 opposite to the first end 21. A pair of first gas nozzles 41 and a pair of second gas nozzles (not shown) are arranged on the upstream and downstream sides of the backup roller 20, respectively.As shown in Figure 4, the pair of first gas nozzles 41 are arranged such that the nozzle opening 41a of one gas nozzle faces the first end 21 of the backup roller 20, and the nozzle opening 41b of the other gas nozzle faces the second end 22 of the backup roller 20. A pair of second gas nozzles (not shown) located downstream of the backup roller 20 are arranged in the same manner as the first gas nozzles 41.

[0012] In the case of Figure 4, the spraying process is carried out at positions upstream and downstream of the position where pressurized water is sprayed, as follows. First, upstream of the backup roller 20, after the laminated film 90 is wound onto the first guide roller GR1, gas is sprayed from a pair of first gas nozzles 41 toward both ends in the width direction of the laminated film (specifically, the coating layer 92) (first spraying step). Next, as the laminated film 90 passes below the backup roller 20 in the -Z axis direction, pressurized water W2 is sprayed toward the coating layer 92 to remove the coating layer 92 (removal step). Next, downstream of the backup roller 20, before the laminated film 90 is wound onto the second guide roller GR2, gas is sprayed from a pair of second gas nozzles (not shown) toward both ends in the width direction of the laminated film (specifically, the base film 91 after the coating layer 92 has been removed), similar to the first spraying step (second spraying step). As described above, by performing the first and second spraying steps, both ends of the laminated film in the width direction are pressed against the backup roller 20 before and after the removal step, and at the same time, water (not shown) adhering to the laminated film is blown outward from both ends of the backup roller 20 in the axial direction. This prevents pressurized water W2 from entering the interface between the back surface (second substrate surface 91b) of the laminated film and the backup roller 20 when performing the removal step. As a result, it is possible to prevent the invading water from acting as a cushion and mitigating the impact force when the pressurized water W2 collides with the coating layer 92. Therefore, the removal method according to this embodiment can improve the removal efficiency of the coating layer. In Figure 4, the case in which the spraying steps are performed at both upstream and downstream positions from the position where the pressurized water is sprayed is described, but for example, only one of the first and second spraying steps may be performed.

[0013] Furthermore, according to the removal method of this embodiment, since it uses virtually only water without using chemicals, there is no need to treat wastewater containing chemicals, which can keep wastewater treatment costs low and also reduce the impact on the global environment.

[0014] <Laminated Film> Figure 1 is a cross-sectional view of a first example of a laminated film used in the removal method according to the first embodiment. The laminated film 90 has a base film 91 and a coating layer 92. The base film 91 has a first base surface 91a on which the coating layer 92 is provided, and a second base surface 91b opposite to the first base surface 91a. The base film 91 and the coating layer 92 are directly laminated. In the laminated film 90, it is preferable that the coating layer 92 includes a release agent layer. In the case of Figure 1, the coating layer 92 is a release agent layer. The coating layer 92 may also include a ceramic green sheet, as shown in Figure 2.

[0015] Figure 2 is a perspective view of a second example of a laminated film used in the removal method according to the first embodiment. Figure 2 shows a laminated film after it has been used in the manufacture of a multilayer ceramic capacitor (MLCC), and after the necessary portion of the ceramic green sheet has been peeled off. The laminated film 90A is wound around a core 1G to form a roll (laminated film roll). An insertion hole 2G is provided in the central part of the core 1G. The laminated film 90A has a base film 91 and a coating layer 92A. The coating layer 92A includes a release agent layer 921 and a ceramic green sheet 922 (residue) from the side of the base film 91. The base film 91 and the release agent layer 921 are directly laminated, and the release agent layer 921 and the ceramic green sheet 922 are directly laminated. The ceramic green sheet 922 is partially provided on the surface of the release agent layer 921. After the ceramic green sheet 922 is peeled off, a recess 930 is formed, and the release agent layer 921 is exposed from the recess 930. The ceramic green sheet 922 may be a green sheet composed of a dielectric as the active ingredient. The ceramic green sheet 922 may be a multilayer including a green sheet composed of a dielectric as the active ingredient and a conductive layer (not shown) composed of a conductor as the active ingredient, from the side of the release agent layer 921. A green sheet is an unfired sheet-like material, and a green sheet with ceramics as the active ingredient is called a ceramic green sheet.

[0016] Each step of the removal method according to this embodiment will be described.

[0017] <Preparation Process, Unwinding Process> The preparation process involves preparing a laminated film roll on which a laminated film having a base film and a coating layer is wound. The unwinding process involves unwinding the laminated film from the laminated film roll. The dimensions of the laminated film are, for example, a width of 100 mm or more and 1000 mm or less, preferably 200 mm or more and 600 mm or less. The length of the laminated film is, for example, 50 m or more and 30000 m or less, preferably 100 m or more and 10000 m or less. The winding diameter of the laminated film roll (the diameter of the roll including the core) is, for example, 100 mm or more and 1500 mm or less, preferably 150 mm or more and 1000 mm or less.

[0018] <Spraying Process> The spraying process involves blowing gas onto both ends of the laminated film, which is being carried wrapped around a backup roller, so as to blow away any water adhering to both ends of the laminated film in the width direction, to the outside of the first end and the second end opposite to the first end in the axial direction of the backup roller. A known gas nozzle can be used as the means for blowing the gas. Examples of gases include air and inert gases. The pressure of the gas nozzle is, for example, 0.1 MPa or more and 10 MPa or less. In this embodiment, it is preferable that the spraying process is a process of pressing both ends of the laminated film in the width direction against the backup roller by blowing gas so that pressurized water does not enter the interface between the laminated film and the backup roller from both ends of the laminated film in the width direction.

[0019] In this embodiment, the spraying process includes a first spraying process performed upstream of the pressurized water injection site and a second spraying process performed downstream of the pressurized water injection site. Preferably, the preparation process, the dispensing process, the first spraying process, the removal process, the second spraying process, and the substrate recovery process are performed in this order.

[0020] <Removal Process> In the removal process, pressurized water is sprayed onto the coating layer of the laminated film as the laminated film passes through the backup roller to remove the coating layer. The water used in the removal process is sprayed toward the coating layer and is used to remove the coating layer. The water is preferably ordinary water, i.e., industrial water, and may be purified water or distilled water. It may also be recycled wastewater used in various industrial productions, or recycled wastewater after it has been used in the implementation of this embodiment. If wastewater is recycled, it may be treated to regenerate the wastewater as appropriate. From the viewpoint of improving work efficiency, the water may contain additives that add functionality as appropriate, but it is preferable not to include them. Examples of additives include surfactants and water-soluble organic solvents. If the water contains additives, the concentration of the active ingredients of the additives in the water is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, relative to the total amount of water, and furthermore, it is preferable that the water is not water to which additives have been intentionally added. Furthermore, it is preferable that the water is neither an alkaline aqueous solution prepared by intentionally adding a basic substance nor an acidic aqueous solution prepared by intentionally adding an acidic substance. Since wastewater can potentially be treated with simple recycling processes, the water may contain basic and acidic substances as additives, but in that case, it is preferable that the pH of the water be between 5.8 and 8.6 in accordance with the uniform wastewater discharge standards (other items) based on the Water Pollution Control Law. The temperature of the water used is preferably room temperature, and it may be cold water or warm water.

[0021] In this specification, the water pressure when spraying water onto the coating layer refers to the pressure of the liquid nozzle (the water pressure applied to the discharge port of the liquid nozzle). In the removal process, the pressure of the liquid nozzle is, for example, 3.0 MPa or more and 70 MPa or less, more preferably 10 MPa or more and 50 MPa or less.

[0022] <Process of circulating to a pump> The removal method according to this embodiment preferably includes a step of filtering the water containing the coating layer removed in the removal step and circulating it to a pump. The means for filtering the water containing the coating layer is, for example, a filter. It is preferable that the water circulated to the pump be reused as water used in the removal step.

[0023] <Draining Process> The removal method according to this embodiment preferably includes a step of draining the water from the base film after the removal process and before the base material recovery process. The draining process is, for example, a step of removing residue from the base film. Residue refers to, for example, the coating layer remaining on the base film, as well as water and foreign matter adhering to the base film. The means of draining the water are not particularly limited, but examples include a draining nozzle (also called an air knife) and a dryer.

[0024] <Substrate Recovery Process> In the substrate recovery process, the substrate film is recovered by known methods.

[0025] [Second Embodiment] [Coating Layer Removal Apparatus] In the second embodiment, the X-axis, Y-axis, and Z-axis are orthogonal to each other, the X-axis and Y-axis are axes in a predetermined plane, and the Z-axis is an axis orthogonal to the predetermined plane. Furthermore, in the second embodiment, when directions are indicated based on the view from the front direction of Figure 3, which is parallel to the Y-axis, "up" is the direction of the Z-axis arrow and "down" is the opposite direction, "right" is the direction of the X-axis arrow and "left" is the opposite direction, "front" is the front direction of Figure 3, which is parallel to the Y-axis and "back" is the opposite direction. Also, in Figure 3, the side closer to the feed shaft 10 is called the "upstream side", and the side closer to the winding shaft 40 is called the "downstream side".

[0026] Figure 3 is a schematic diagram of the coating layer removal device 100 according to the second embodiment. The removal device 100 is a roll-to-roll device that removes the coating layer from a laminated film having a base film and a coating layer. In the second embodiment, an example of removing the coating layer 92 from the laminated film 90 shown in Figure 1 using the removal device 100 will be described.

[0027] The removal device 100 according to the second embodiment includes: a feed shaft 10 for feeding out a laminated film 90 from a laminated film roll in which the laminated film is wound in a roll shape; a backup roller 20 arranged downstream of the feed shaft 10 for winding the laminated film 90 and transporting it downstream; a spray unit 31 arranged opposite the backup roller 20 and including one or more liquid nozzles, which sprays water onto the coating layer 92 from one or more liquid nozzles so as the laminated film passes the backup roller to remove the coating layer 92; one or more gas nozzles arranged at least one upstream and downstream of the spray unit 31 for blowing gas onto the laminated film 90 wound on the backup roller 20; a pressurized water supply unit 50 for pressurizing water and supplying pressurized water W2 to the spray unit 31; one or more gas supply units 35 for pressurizing gas and supplying gas to one or more gas nozzles; and a winding shaft 40 for winding the base film 91 in a roll shape after the coating layer 92 has been removed. The one or more gas nozzles have multiple gas nozzle openings, and the multiple gas nozzle openings are arranged facing the first or second end side in the axial direction of the backup roller 20 so as to blow water adhering to both ends of the laminated film 90 in the width direction to the outside of the first end side and the second end side opposite to the first end side in the axial direction of the backup roller 20. Preferably, the one or more gas nozzles are arranged both upstream and downstream of the injection unit 31. In the second embodiment, the one or more gas nozzles are a pair of first gas nozzles 41 and a pair of second gas nozzles 42. The pressurized water supply unit 50 includes a pump (in the case of Figure 3, a supply pump 62), and the injection unit 31 is connected to the pump. The removal device 100 also includes a water recovery and regeneration device 60, a residue removal device 70, a plurality of nip rolls NR1, NR2, NR3, NR4, and a plurality of guide rollers GR. Known rollers can be used as guide rollers GR.

[0028] The removal device 100 according to the second embodiment is equipped with a pair of gas nozzles 41 and 42 upstream and downstream of the injection unit 31, so that when pressurized water W2 is injected from the injection unit 31, both ends in the width direction of the laminated film are pressed against the backup roller 20 on the upstream and downstream sides. This prevents pressurized water W2 from entering the interface between the back surface (second substrate surface 91b) of the laminated film 90 and the backup roller 20 when pressurized water W2 is injected from the injection unit 31. As a result, the injection unit 31 can prevent the injected water from acting as a cushion and mitigating the impact force when the pressurized water W2 collides with the coating layer 92. Therefore, the removal device 100 according to the second embodiment can improve the efficiency of removing the coating layer.

[0029] The components of the removal device 100 according to the second embodiment will now be described.

[0030] <Feeding shaft 10> The feeding shaft 10 feeds out the laminated film 90 from the laminated film roll, which is wound in a roll shape. The feeding shaft 10 is connected to a drive roller (not shown).

[0031] <Injection Unit 31> The injection unit 31 includes one or more liquid nozzles positioned opposite the backup roller 20. As the laminated film 90 passes over the backup roller 20, water is injected from one or more liquid nozzles onto the coating layer 92 to remove the coating layer 92 of the laminated film 90. In the injection unit 31, from the viewpoint of applying water impact pressure to the surface of the coating layer 92, it is preferable that the central axes of the one or more liquid nozzles in the injection unit 31 are perpendicular to the tangent to the outer circumference of the backup roller 20 when viewed in a cross-section perpendicular to the central axis 20a of the backup roller 20. The injection unit 31 is positioned inside the injection chamber 301 and is configured so that the injected water is guided to the tank 53 of the water recovery and regeneration device 60. The shape of the liquid nozzles is not particularly limited, but it is preferable that they be flow-constricting nozzles. A flow-constricting nozzle refers to a nozzle that ejects water from a constricted outlet, such as an orifice and a flow nozzle. When the nozzle is a flow-constricting nozzle, the inner diameter of the nozzle outlet is the inner diameter of the constricted section. The pattern of the liquid nozzle is not particularly limited, but examples include a flat pattern (spraying in a fan shape from the nozzle), a full cone pattern (spraying in a cone shape from the nozzle), and a straight pattern (spraying in a linear shape from the nozzle). Among these, a flat pattern is preferred for the liquid nozzle. In roll-to-roll applications, a flat pattern can break down and remove the coating layer with fewer nozzles and less water compared to a straight pattern.

[0032] <Pressurized Water Supply Unit 50> The pressurized water supply unit 50 pressurizes water and supplies pressurized water W2 to the injection unit 31. The pressurized water supply unit 50 includes a supply pump 62, and the injection unit 31 is connected to the supply pump 62. The pressurized water supply unit 50 is, for example, a known pressurized water generator. The pressurized water supply unit 50 comprises a water source 55, a tank 53 for storing water W1, piping 54 connecting the water source 55 and the tank 53, and a supply pump 62. The supply pump 62 is connected to the injection unit 31 via piping 531. The tank 53 stores water supplied from the water source 55 and water recycled by the water recovery and recycling device 60. In the pressurized water supply unit 50, the water W1 stored in the tank 53 is used when generating pressurized water. The supply pump 62 pressurizes the water W1 and supplies pressurized water W2 to the injection unit 31.

[0033] <Gas Nozzles> In this embodiment, one or more gas nozzles include a pair of first gas nozzles 41 and a pair of second gas nozzles 42. The pair of first gas nozzles 41 are arranged upstream of the injection unit 31, and the pair of second gas nozzles 42 are arranged downstream of the injection unit 31. In the removal device 100, it is preferable that the pair of first gas nozzles 41 are arranged in a position and orientation that allows them to blow gas toward the vicinity of the point where the laminated film and the backup roller first come into contact (contact point T1 in the case of Figure 3), and toward both ends in the width direction of the laminated film (in the case of Figure 4, toward the first end 21 and the second end 22 in the axial direction of the backup roller 20). Furthermore, it is preferable that the pair of second gas nozzles 42 be positioned and oriented so as to be able to spray gas toward the vicinity of the point where the laminated film (specifically, the base film 91 after the coating layer 92 has been removed) and the backup roller first separate (contact point T2 in the case of Figure 3), and toward both ends in the width direction of the laminated film (in the case of Figure 4, toward the first end 21 and the second end 22 in the axial direction of the backup roller 20). Note that when the gripping angle of the laminated film with respect to the backup roller 20 is small, the points where the laminated film and the backup roller first make contact and first separate (contact points T1, T2 in the case of Figure 3) are close to the injection position of the pressurized water W2 in the injection unit 31. On the other hand, when the gripping angle of the laminated film with respect to the backup roller 20 is large, the points where the laminated film and the backup roller first make contact and first separate (contact points T1, T2 in the case of Figure 3) are farther from the injection position of the pressurized water W2 in the injection unit 31. The pair of first gas nozzles 41 and the pair of second gas nozzles 42 may have the same configuration or different configurations. The structure of one or more gas nozzles is not limited to a pair of gas nozzles.

[0034] <Gas supply unit 35> The gas supply unit 35 pressurizes the gas and supplies it to one or more gas nozzles 41, 42. Examples of the gas supply unit 35 include gas cylinders.

[0035] <Water Recovery and Recycling Device 60> The water recovery and recycling device 60 separates water from the coating layer (detached material) by passing the water ejected from the injection unit 31 through a filtration filter 71. The water recovery and recycling device 60 comprises a tank 53, a filtration filter 71, and a recovery pump 61 positioned between the tank 53 and the filtration filter 71.

[0036] <Residue Removal Device 70> The residue removal device 70 is a device that removes residue adhering to the base film 91, and is an example of a means for dewatering the base film. The residue removal device 70 is located downstream of the backup roller 20 and upstream of the winding shaft 40. Residue refers to, for example, the coating layer 92 remaining on the base film 91, as well as water and foreign matter adhering to the base film 91. The residue removal device 70 is not particularly limited, but for example, the aforementioned means for dewatering can be cited. In the case of Figure 3, the residue removal device 70 is a pair of dewatering nozzles.

[0037] <Winding shaft 40> The winding shaft 40 is located downstream of the backup roller 20 and winds the base film into a roll after the coating layer has been removed. The winding shaft 40 is connected to a drive roller (not shown).

[0038] The present invention is not limited to the embodiments described above. The present invention may include modifications and improvements to the extent that the objectives of the present invention can be achieved. The removal device of the second embodiment may be equipped with a residue detection device downstream of the backup roller and upstream of the winding shaft. The residue detection device is a device for detecting the residue of the coating layer, and is, for example, a film thickness gauge for measuring the film thickness of the coating layer. In addition, the residue detection device may have a foreign matter detection function as well as a function for detecting residue of the coating layer.

[0039] The structure of the laminated film will be explained.

[0040] [Laminated Film] The laminated film used in the above-described embodiment comprises a base film and a coating layer. The coating layer may be a single layer or a multi-layer consisting of two or more coating layers of the same or different type. From the viewpoint of making it easier to remove the coating layer from the laminated film and recover the remaining base film, it is preferable that the base film and the coating layer are directly laminated. Here, "direct lamination" refers to a configuration in which, for example, there is no other layer between the base film and the coating layer, and the base film and the coating layer are in direct contact with each other.

[0041] <Base Film> The base film used is a resin film on which the resin component intended for recovery has been formed. Suitable resin films include polyester films such as polyethylene terephthalate film, polybutylene terephthalate, and polyethylene naphthalate; polyolefin films such as polyethylene film and polypropylene film; polyimide film; polyamide film; polycarbonate film; polyacetate film; ethylene-vinyl acetate copolymer (EVA) film; ethylene-(meth)acrylic acid copolymer film; ethylene-(meth)acrylic acid ester copolymer film; cycloolefin polymer film; polyurethane film; polyphenylene sulfide film; cellophane; and others. Among the base films, polyester film is preferred due to its excellent heat resistance and strength. As for polyester films, polyester films with polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate as the main constituent component are preferred from the viewpoint of facilitating resin recovery and regeneration. In this specification, the main constituent component or principal component means that the proportion of the total mass of the material is 50% by mass or more. Furthermore, the resin film may contain known fillers, colorants, antistatic agents, antioxidants, organic lubricants, and catalysts. The resin film may be transparent or colored as desired. In addition, at least one surface of the base film may be subjected to surface treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, and oxidation etching as needed.

[0042] There are no particular restrictions on the thickness of the base film, but from the viewpoint of strength, rigidity, etc., it is preferably 10 μm to 500 μm, more preferably 15 μm to 300 μm, and even more preferably 20 μm to 200 μm.

[0043] <Coating layer> It is preferable that the coating layer is a functional layer. Examples of the functional layer include a release agent layer, an intermediate layer, a printing layer, a hard coat layer, an easy adhesion layer, and an adhesive layer. The coating layer may include a functional layer and a ceramic green sheet, or may include a functional layer, a ceramic green sheet, and a conductive layer. It is preferable that the coating layer includes at least a release agent layer.

[0044] (Release agent layer) When the coating layer is a release agent layer, it is preferable that the release agent layer is a layer formed from a release agent composition. The release agent composition used for forming the release agent layer is not particularly limited as long as it has releasability. For example, a release agent composition mainly composed of a silicone-based compound; a fluorine compound; a long-chain alkyl group-containing compound; a thermoplastic resin material such as an olefin-based resin or a diene-based resin; etc. can be used. Also, it is preferable to use a release agent composition mainly composed of an energy ray-curable or thermosetting resin. These release agent compositions may be used alone or in combination of two or more.

[0045] In a release agent composition mainly composed of a silicone-based compound, examples of the silicone-based compound include a silicone-based compound having an organopolysiloxane as a basic skeleton. Also, examples of the silicone-based compound include thermosetting silicone-based compounds such as addition reaction type and condensation reaction type; energy ray-curable silicone-based compounds such as ultraviolet ray-curable type and electron beam-curable type; etc.

[0046] In a release agent composition mainly composed of a fluorine compound, examples of the fluorine compound include a fluorosilicone compound, a fluorine boron compound, and a compound containing a poly(perfluoroalkylene ether) chain.

[0047] In a release agent composition containing a long-chain alkyl group-containing compound as a main component, examples of the long-chain alkyl group-containing compound include polyvinyl carbamate obtained by reacting a polyvinyl alcohol-based polymer with a long-chain alkyl isocyanate, an alkyl urea derivative obtained by reacting polyethyleneimine with a long-chain alkyl isocyanate, or a copolymer of a long-chain alkyl (meth)acrylate. Further, a long-chain alkyl-modified alkyd resin obtained by using a long-chain fatty acid as a modifier in an alkyd resin obtained by a condensation reaction of a polyhydric alcohol and a polybasic acid may be used.

[0048] As a release agent composition containing an energy ray-curable resin as a main component, for example, those containing an energy ray-curable compound having a reactive functional group selected from a (meth)acryloyl group, an alkenyl group, and a maleimide group and a polyorganosiloxane are preferable. In the release agent layer formed by this release agent composition, since an energy ray-curable compound and a polyorganosiloxane having different molecular structures, polarities, and molecular weights are used, components derived from the polyorganosiloxane are segregated near the outer surface of the release agent layer before curing, and then cured by energy rays and the segregation is fixed. Thereby, the releasability of the release agent layer can be improved. The release agent composition containing an energy ray-curable resin as a main component may further contain a photoinitiator.

[0049] Examples of release agent compositions mainly composed of thermosetting resins include release agent compositions mainly composed of melamine resin and release agent compositions mainly composed of epoxy resin. Examples of release agent compositions mainly composed of melamine resin include a composition containing melamine resin as the main component, an acid catalyst for thermosetting the melamine resin, and a polyorganosiloxane that imparts release properties to the release agent layer. Examples of release agent compositions mainly composed of epoxy resin include a composition containing epoxy resin as the main component, an acid or basic thermosetting catalyst for thermosetting the epoxy resin, and a polyorganosiloxane that imparts release properties to the release agent layer. Before curing, components derived from polyorganosiloxane segregate near the outer surface of the release agent layer, and then the segregation is fixed after curing. This improves the release properties of the release agent layer.

[0050] Furthermore, the coating layer may contain other additives in addition to the resin components mentioned above. Examples of other additives include anti-aging agents, light stabilizers, flame retardants, conductive agents, antistatic agents, and plasticizers.

[0051] The thickness of the coating layer can be selected as appropriate and is not particularly limited, but for example, it is preferably 0.02 μm to 5 μm, more preferably 0.03 μm to 2 μm, and even more preferably 0.05 μm to 1.5 μm.

[0052] (Ceramic Green Sheet) The coating layer preferably includes a release agent layer and a ceramic green sheet. In this case, the laminated film preferably has the base film, the release agent layer, and the ceramic green sheet directly laminated in this order.

[0053] A ceramic green sheet can be obtained, for example, by coating the surface of a coating layer opposite the substrate film with a ceramic slurry, and then drying the ceramic slurry. Coating can be performed using, for example, a slot die coating method or a doctor blade method. The ceramic slurry contains ceramic powder, a binder component, and a solvent. Examples of ceramic powders include dielectric powders such as barium titanate, titanium oxide, alumina, zirconia, zinc oxide, aluminum silicate, and silicon nitride. When dielectric powder is used as the ceramic powder, a green sheet used in the manufacture of multilayer ceramic capacitors (MLCCs) can be obtained (specifically, a green sheet composed of dielectric as the active ingredient). The ceramic powder may also be a ceramic powder other than a dielectric. The thickness of the ceramic green sheet is, for example, 0.1 μm to 10 μm.

[0054] (Conductive layer) When the coating layer includes a release agent layer, a ceramic green sheet, and a conductive layer, it is preferable that the laminated film is directly laminated in this order: the base film, the release agent layer, the ceramic green sheet, and the conductive layer. The conductive layer is not particularly limited, and a conductive layer used in the manufacture of electronic components can be used. The conductive layer is formed on the ceramic green sheet, for example, by applying a conductive paste. The thickness of the conductive layer is, for example, 0.1 μm or more and 5 μm or less.

[0055] (Intermediate layer) The coating layer may include a release agent layer and an intermediate layer. In this case, it is preferable that the intermediate layer and the release agent layer are directly laminated in this order from the base film side. Alternatively, the coating layer may be directly laminated with the intermediate layer, release agent layer and ceramic green sheet in this order from the base film side. Or, the coating layer may be directly laminated with the intermediate layer, release agent layer, ceramic green sheet and conductive layer in this order from the base film side. Examples of intermediate layers include a water-soluble intermediate layer, an alkali-degradable intermediate layer, and a layer that is hydrophilic and water-insoluble.

[0056] (Water-soluble intermediate layer) When the intermediate layer is a water-soluble intermediate layer, examples of water-soluble resins included in the intermediate layer include water-soluble polyvinyl alcohol resin, water-soluble acrylic resin, water-soluble polyester resin, water-soluble polyester urethane resin, water-soluble ethylene ionomer resin, water-soluble polyvinylpyrrolidone resin, water-soluble poly-N-vinylacetamide resin, water-soluble polyamide resin, water-soluble ethylene-vinyl alcohol resin, and water-soluble starch. The content of water-soluble resin in the intermediate layer is preferably 30% by mass or more and 90% by mass or less, and more preferably 40% by mass or more and 80% by mass or less, based on the total mass of the intermediate layer. The upper limit of the content of water-soluble resin in the intermediate layer is 100% by mass.

[0057] (Alkali-degradable intermediate layer) When the intermediate layer is an alkali-degradable intermediate layer, examples of alkali-degradable resins included in the intermediate layer include phenolic resin, polyacrylic acid, polyamide resin, polyester resin, and polylactic acid. The content of alkali-degradable resin in the intermediate layer is preferably 30% by mass or more and 90% by mass or less, and more preferably 40% by mass or more and 80% by mass or less, based on the total mass of the intermediate layer. The upper limit of the content of water-soluble resin in the intermediate layer is 100% by mass.

[0058] (Hydrophilic and water-insoluble layer) When the intermediate layer is a hydrophilic and water-insoluble layer, it is preferable that the intermediate layer is made of a silane compound that exhibits polycondensation by hydrolysis, from the viewpoint of more easily separating the coating layer from the substrate film side surface of the intermediate layer.

[0059] When the intermediate layer is hydrophilic and water-insoluble, the silane compound is preferably a tetraalkoxysilane. More preferred specific examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Among these, from the viewpoint of ease of availability and reactivity of the hydrolysis reaction, at least one of tetramethoxysilane and tetraethoxysilane, or a mixture of tetramethoxysilane and tetraethoxysilane, is preferred. Commercially available products can also be used as the hydrolysis polycondensate of the silane compound.

[0060] When the intermediate layer contains a hydrophilic and water-insoluble resin (preferably the silane compound), the content of the hydrophilic and water-insoluble resin is preferably 30% to 90% by mass, and more preferably 40% to 80% by mass, relative to the total mass of the intermediate layer. The upper limit for the content of the hydrophilic and water-insoluble resin in the intermediate layer is 100% by mass.

[0061] The thickness of the intermediate layer is preferably 0.01 μm to 1 μm, more preferably 0.03 μm to 0.5 μm, and even more preferably 0.05 μm to 0.3 μm, from the viewpoint of facilitating moisture penetration when the intermediate layer comes into contact with water.

[0062] The laminated films used in each embodiment are generally used to protect the surfaces of other functional sheets and various components used for specific applications during manufacturing, transportation, and storage. After fulfilling their protective role, they are often peeled off the surface and discarded. Therefore, by using the laminated film, the coating layer and the base film can be easily separated from the laminated film, making it a highly beneficial application from the standpoint of resource conservation and environmental protection.

[0063] 10...feeding shaft, 20...backup roller, 20a...central axis, 21...first end, 22...second end, 31...injection unit, 35...gas supply unit, 40...winding shaft, 41, 42...gas nozzle, 41a, 41b...nozzle opening, 50...pressurized water supply unit, 53...tank, 54...piping, 55...water source, 60...water recovery and recycling device, 61...recovery pump, 62...supply pump, 70...residue removal device, 71...filtration filter, 90, 90A...laminated film, 91...base film, 92, 92A...coating layer, 100...removal device, 301...injection chamber, 531...piping, 921...release agent layer, 922...ceramic green sheet.

Claims

1. A method for removing a coating layer, comprising the steps of: preparing a laminated film roll around which a laminated film having a base film and a coating layer is wound; unwinding the laminated film from the laminated film roll; blowing gas toward both ends of the laminated film, which is being conveyed wound around a backup roller, so as to blow away water adhering to both ends of the laminated film in the width direction toward the outside of the first end and the second end opposite to the first end in the axial direction of the backup roller; removing the coating layer by spraying pressurized water onto the coating layer of the laminated film as the laminated film passes through the backup roller; and recovering the base film after the coating layer has been removed by winding it into a roll, wherein the spraying step is performed at least on one side upstream and downstream of the position where the pressurized water is sprayed.

2. The method for removing a coating layer according to claim 1, wherein the spraying step comprises a first spraying step performed upstream of the position from which the pressurized water is sprayed, and a second spraying step performed downstream of the position from which the pressurized water is sprayed, and the preparation step, the dispensing step, the first spraying step, the removal step, the second spraying step, and the substrate recovery step are performed in this order.

3. The method for removing a coating layer according to claim 1 or claim 2, wherein the spraying step is a step of pressing both ends in the width direction of the laminated film against the backup roller by spraying the gas so that the pressurized water does not penetrate into the interface between the laminated film and the backup roller from both ends in the width direction of the laminated film.

4. A method for removing a coating layer according to claim 1 or 2, further comprising the step of filtering the water containing the coating layer removed in the removal step and circulating it to a pump.

5. A method for removing a coating layer according to claim 1 or 2, further comprising a step of draining the water from the substrate film after the removal step and before the substrate recovery step.

6. The method for removing a coating layer according to claim 1 or claim 2, wherein the coating layer includes a release agent layer.

7. The method for removing a coating layer according to claim 6, wherein the coating layer includes a ceramic green sheet.

8. A coating layer removal apparatus for removing a coating layer from a laminated film having a base film and a coating layer, comprising: a feed shaft for feeding the laminated film from a laminated film roll in which the laminated film is wound in a roll shape; a backup roller disposed downstream of the feed shaft for winding the laminated film and transporting it downstream; a spray unit disposed opposite the backup roller and including one or more liquid nozzles for spraying water from the one or more liquid nozzles onto the coating layer so as the laminated film passes the backup roller to remove the coating layer; one or more gas nozzles disposed at least one upstream and downstream of the spray unit for blowing gas onto the laminated film wound on the backup roller; a pressurized water supply unit for pressurizing water and supplying pressurized water to the spray unit; one or more gas supply units for pressurizing gas and supplying gas to the one or more gas nozzles; and a winding shaft for winding the base film in a roll shape after the coating layer has been removed, wherein the pressurized water supply unit includes a pump, and the spray unit is connected to the pump. A coating layer removal device wherein the one or more gas nozzles have a plurality of gas nozzle openings, and the plurality of gas nozzle openings are arranged facing the first end side or the second end side in the axial direction of the backup roller so as to blow away water adhering to both ends of the laminated film in the width direction to the outside of the first end side in the axial direction of the backup roller and to the outside of the second end side opposite to the first end side.

9. The coating layer removal apparatus according to claim 8, wherein the one or more gas nozzles are arranged both upstream and downstream of the injection unit.

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