Coating layer removal method and coating layer removal device

Abstract

A coating layer (92) removal method for removing a coating layer (92) from a layered film (90) having a substrate film and the coating layer (92), said coating layer (92) removal method having: an ultrasonic wave application step in which ultrasonic wave vibration is applied to the layered film (90) to apply a shock to the coating layer (92); and a removal step in which, after the ultrasonic wave application step, water is jetted at the coating layer (92) and the coating layer (92) is removed.

Description

Method for Removing Coating Layer and Coating Layer Removal Apparatus

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

[0002] In recent years, from the viewpoints of global resource protection and environmental protection, in various fields, initiatives such as suppressing the generation of waste, reusing, and recycling are being actively promoted to aim for the construction of 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 with high-pressure jet water and crushing and recycling the plastic body. Patent Document 2 discloses a method for peeling a laminated film, which comprises at least a step of unwinding the laminated film, a step of supplying warm water to the surface of the unwound laminated film, a step of peeling the surface laminated portion from the laminated film, and a step of winding up the base film after peeling, and wherein the surface laminated portion is peeled after bringing warm water into contact with the surface of the laminated film for 2 seconds or more.

[0003] Japanese Patent Application Laid-Open No. 5-269743 Japanese Patent Application Laid-Open No. 2004-363140

[0004] Patent Document 1 describes that, in advance, after damaging the coating film of a bumper with a hammer or the like, the coating film is peeled from the plastic body by strongly jetting high-pressure jet water onto the coating film. The technique described in Patent Document 1 is for removing a coating film formed on a plastic body and thus cannot be applied to a technique for removing a coating layer formed on a thin base film. In the method described in Patent Document 2, in a warm water tank, while transporting the laminated film, the surface of the laminated film is rubbed with a brush roll to peel the surface functional layer from the laminated film. However, in the method described in Patent Document 2, the surface functional layer may not be sufficiently peeled.

[0005] An object of the present invention is to provide a method for removing a coating layer and a coating layer removal apparatus capable of easily removing a coating layer from a laminated film.

[0006] [1] A method for removing a coating layer from a laminated film having a base film and a coating layer, comprising: an ultrasonic application step of applying ultrasonic vibration to the laminated film to impact the coating layer; and a removal step of spraying water onto the coating layer after the ultrasonic application step to remove the coating layer. [2] The method for removing a coating layer according to [1], wherein the ultrasonic application step is performed by applying ultrasonic vibration to the laminated film while bringing the coating layer of the laminated film into contact with an ultrasonic horn. [3] The method for removing a coating layer according to [2], wherein the ultrasonic application step is performed by applying ultrasonic vibration to the laminated film while pressing the laminated film between a backup roller and the ultrasonic horn. [4] A method for removing a coating layer according to any one of [1] to [3], further comprising: preparing a laminated film roll in which the laminated film is wound in a roll shape; unwinding the laminated film from the laminated film roll; and recovering the base film after the coating layer has been removed in the removal step by winding it into a roll shape, wherein the preparation step, the unwinding step, the ultrasonic application step, the removal step, and the base film recovery step are performed in this order, and the steps from the unwinding step to the base film recovery step are performed roll to roll. [5] A method for removing a coating layer according to [4], further comprising: filtering the water containing the coating layer removed in the removal step and circulating it to a pump. [6] A method for removing a coating layer according to [4] or [5], further comprising: a step of draining the water from the base film after the removal step and before the base film recovery step. [7] A method for removing a coating layer according to any one of [1] to [6], wherein the coating layer includes a release agent layer. [8] The method for removing the coating layer according to [7], wherein the coating layer includes a ceramic green sheet.[9] A coating layer removal device 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; an ultrasonic vibration unit disposed downstream of the feed shaft and applying ultrasonic vibration to the laminated film to impact the coating layer; a backup roller disposed downstream of the ultrasonic vibration unit and transporting the laminated film downstream; a spray unit including one or more nozzles disposed opposite the backup roller and spraying pressurized water from the one or more nozzles onto the coating layer to remove the coating layer of the laminated film as the laminated film passes the backup roller; a pressurized water supply unit for supplying pressurized water to the spray unit; and a winding shaft disposed downstream of the backup roller and 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.

[10] The coating layer removal device according to [9], wherein the ultrasonic vibration unit is an ultrasonic horn.

[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 allow the coating layer to be easily removed 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 ultrasonic application process of the first embodiment, which is an enlarged perspective view of the ultrasonic vibration section viewed from the downstream side.

[0009] [First Embodiment] [Method for Removing the Coating Layer] The method for removing the coating layer according to this embodiment (hereinafter also referred to as the removal method according to this embodiment) is a method for removing the coating layer from a laminated film having a base film and a coating layer, and comprises an ultrasonic application step of applying ultrasonic vibrations to the laminated film to impact the coating layer, and a removal step of spraying water onto the coating layer after the ultrasonic application step to remove the coating layer.

[0010] In the removal method according to this embodiment, a removal step is performed to remove the coating layer after performing an ultrasonic application step. The ultrasonic application step will be explained with reference to Figures 1 and 4. In the following explanation, an example in which the ultrasonic application step is performed while the laminated film is being transported will be described. An ultrasonic horn 81 shown in Figure 4 is used as the ultrasonic application means, and a laminated film 90 shown in Figure 1 is used as the 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 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 shows the state in which the coating layer 92 of the laminated film 90 is impacted by the ultrasonic vibration unit 80. The ultrasonic vibration unit 80 comprises a roll-shaped (cylindrical) ultrasonic horn 81, a backup roller 82 positioned opposite the ultrasonic horn 81, an ultrasonic transducer 83, and an ultrasonic oscillator 84. The ultrasonic oscillator 84 supplies high-frequency power (e.g., 10 kHz or higher) to the ultrasonic transducer 83. The ultrasonic transducer 83 generates vibrations, and the ultrasonic horn 81 amplifies these vibrations. The ultrasonic application process applies the amplified vibrations from the ultrasonic horn 81 to the laminated film 90, thereby impacting the coating layer 92. This causes cracks to form in the coating layer 92 or weakens it. In the case of Figure 4, since ultrasonic vibrations are applied to the laminated film while the laminated film 90 is pressed by the ultrasonic horn 81 and the backup roller 82, ultrasonic application is possible even in a roll-to-roll configuration. When cracks are to form, it is preferable to reach the interface between the base film 91 and the coating layer 92. Furthermore, the impact that causes cracks in the coating layer may cause the coating layer to partially peel off from the surface of the base film. Even without cracks, the coating layer 92 becomes weakened, making it easy to remove in the subsequent removal step. According to the removal method of this embodiment, the coating layer is subjected to an impact in the ultrasonic application step, and then the removal step of removing the coating layer is performed.This allows the coating layer to be easily removed from the laminated film in the subsequent removal process. Furthermore, according to the removal method of this embodiment, since the coating layer is removed using substantially only water in the removal process without the use of chemicals, there is no need to treat wastewater containing chemicals, which can reduce wastewater treatment costs and minimize the impact on the global environment.

[0011] <Laminated Film> A second example of a laminated film used in the removal method according to the first embodiment will be described. 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. When the laminated film 90A shown in Figure 2 is used, the ultrasonic application process can impact the multilayer coating layer 92A (release agent layer 921 and ceramic green sheet 922), so that the multilayer coating layer 92A can be easily removed from the laminated film 90A in the subsequent removal process. The ceramic green sheet 922 may be a green sheet composed of a dielectric as an active ingredient. The ceramic green sheet 922 may be a multilayer including a green sheet composed of a dielectric as an active ingredient and a conductive layer (not shown) composed of a conductor as an 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 an active ingredient is called a ceramic green sheet.

[0012] Each step of the removal method according to this embodiment will be described.

[0013] <Ultrasonic Application Process> The ultrasonic application process involves applying ultrasonic vibrations to the laminated film to impact the coating layer. A known ultrasonic horn can be used as the ultrasonic application means (means for applying ultrasonic vibrations). The shape of the ultrasonic horn is not particularly limited. In this embodiment, the ultrasonic application process is preferably a process of applying ultrasonic vibrations to the laminated film while the ultrasonic horn is in contact with the coating layer of the laminated film. In this embodiment, the ultrasonic application process is preferably a process of applying ultrasonic vibrations to the laminated film while pressing the laminated film between a backup roller and an ultrasonic horn. In this case, the shape of the ultrasonic horn is preferably roll-shaped. In the ultrasonic application process, the oscillation frequency when applying ultrasonic vibrations to the laminated film is preferably 10 kHz or more and 300 kHz or less, more preferably 20 kHz or more and 200 kHz or less. In the ultrasonic application process, the ultrasonic output density is preferably 0.1 W / cm². ２ Above, 2.0W / cm ２ More preferably, 0.3 W / cm² ２ Above, 1.5W / cm ２ The following applies: The ultrasonic output density is calculated by dividing the ultrasonic output set in the ultrasonic oscillator by the area of ​​the tip of the ultrasonic horn (or, if the ultrasonic horn is roll-shaped, the area of ​​contact between the ultrasonic horn and the coating layer). In the ultrasonic application process, the time for which ultrasonic vibrations are applied to the laminated film (application time) is usually 10 seconds or less. The lower limit of the application time is, for example, 0.01 seconds or more. When ultrasonic vibrations are applied to the laminated film with a roll-shaped ultrasonic horn, the application time is the time it takes for the laminated film to pass through the ultrasonic horn, and this time is determined by the transport speed of the laminated film.

[0014] <Removal Process> In the removal process, after the ultrasonic application process, water is sprayed onto the coating layer to remove it. The water used in the removal process is sprayed towards the coating layer and used to remove it. 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 not an alkaline aqueous solution prepared by intentionally adding a basic substance, nor is it preferable that it is not an acidic aqueous solution prepared by intentionally adding an acidic substance. Since wastewater can potentially be treated with simple recycling methods, the water may contain basic and acidic substances as additives. In such cases, it is preferable that the pH of the water be between 5.8 and 8.6 to comply with the uniform wastewater discharge standards (other items) based on the Water Pollution Control Law. The water used is preferably at room temperature and may be either cold or warm water.

[0015] In this specification, the water pressure when spraying water onto the coating layer refers to the nozzle pressure (the water pressure applied to the nozzle outlet). In the removal step, the nozzle pressure is, for example, 1.0 MPa or more and 50 MPa or less, more preferably 3.0 MPa or more and 30 MPa or less. The removal step is preferably a step of spraying water toward the coating layer of the laminated film while the laminated film is supported by a backup roller. In this case, the removal step is preferably a step of spraying water toward the coating layer of the laminated film from one or more nozzles positioned opposite the backup roller while the backup roller is in contact with the second substrate surface 91b (Figure 1) of the base film.

[0016] <Roll-to-Roll> The removal method according to this embodiment further comprises the steps of: preparing a laminated film roll in which the laminated film is wound in a roll shape; unwinding the laminated film from the laminated film roll; and recovering the base film after the coating layer has been removed in the removal step by winding it into a roll shape. The preparation step, unwinding step, ultrasonic application step, removal step, and base film recovery step are performed in this order, and it is preferable that the steps from unwinding to base film recovery are performed roll-to-roll. By performing the removal method according to this embodiment roll-to-roll, the base film can be recovered continuously while the coating layer is easily removed.

[0017] (Preparation process, unwinding process) The preparation process involves preparing a laminated film roll in which the laminated film is wound into a roll shape. 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] (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. The water circulated to the pump is preferably reused as water used in the removal step.

[0019] (Draining step) The removal method according to this embodiment preferably includes a step of draining the water from the base film after the removal step and before the base material recovery step. The draining step 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.

[0020] (Substrate recovery process) In the substrate recovery process, the substrate film is recovered by known methods.

[0021] [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".

[0022] Figure 3 is a schematic diagram of the coating layer removal device 100 according to the second embodiment. The removal device 100 is a device that removes the coating layer from a laminated film after impacting the coating layer of the laminated film with an ultrasonic vibration unit. In the second embodiment, an example in which the laminated film 90 shown in Figure 1 is used as the laminated film will be described.

[0023] The removal device 100 according to the second embodiment includes a feed shaft 10 that feeds out the laminated film 90 from a laminated film roll in which the laminated film 90 is wound in a roll shape, an ultrasonic vibration unit 80 located downstream of the feed shaft 10 that applies ultrasonic vibration to the laminated film 90 to impact the coating layer 92, a backup roller 20 located downstream of the ultrasonic vibration unit 80 that transports the laminated film 90 downstream, a spray unit 31 located opposite the backup roller 20 and including one or more nozzles that spray pressurized water W3 onto the coating layer 92 from one or more nozzles to remove the coating layer of the laminated film as the laminated film 90 passes the backup roller 20, a pressurized water supply unit 50 that pressurizes water and supplies pressurized water W3 to the spray unit 31, and a winding shaft 40 located downstream of the backup roller 20 that winds the base film 91 after the coating layer 92 has been removed into a roll shape. The pressurized water supply unit 50 includes a pump (in the case of Figure 3, a supply pump 51), and the spray unit 31 is connected to the pump. Furthermore, the removal device 100 includes a water recovery and regeneration device 60, a residue removal device 70, a residue detection device 75, nip rollers NR1 and NR2, and a plurality of guide rollers GR. Known rollers can be used as the guide rollers GR.

[0024] According to the removal device 100 of the second embodiment, an ultrasonic vibration unit 80 and a jet unit 31 downstream of the ultrasonic vibration unit 80 are provided, so that the coating layer 92 of the laminated film 90 is struck and then the coating layer is removed. This makes it possible to continuously recover the base film 91 while easily removing the coating layer 92 in a roll-to-roll manner.

[0025] The components of the removal device 100 according to the second embodiment will now be described.

[0026] <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).

[0027] <Ultrasonic Vibration Unit 80> The ultrasonic vibration unit 80 is positioned downstream of the feed shaft 10 and applies ultrasonic vibrations to the laminated film 90 to impact the coating layer. In Figure 3, the ultrasonic vibration unit 80 is equipped with a roll-shaped ultrasonic horn 81 (an example of an ultrasonic application means). Figure 4 is an enlarged perspective view of the ultrasonic vibration unit 80 as seen from the downstream side. As described above, the ultrasonic vibration unit 80 is equipped with an ultrasonic horn 81, a backup roller 82, an ultrasonic transducer 83, and an ultrasonic oscillator 84. The ultrasonic horn 81, the ultrasonic transducer 83, and the ultrasonic oscillator 84 are connected to each other. The axial length of the ultrasonic horn 81 is preferably equal to or greater than the width of the laminated film 90. This applies fine vibrations to the entire coating layer, making it easier for cracks or weakening to occur throughout the coating layer.

[0028] <Backup Roller 20> The backup roller 20 is positioned downstream of the ultrasonic vibration unit 80 and transports the laminated film 90 downstream. By passing the laminated film 90 over the backup roller 20, the vertical (Z-axis direction) play (escape) of the laminated film 90 caused by the impact of pressurized water W3 from the nozzle is eliminated, and the tension in the surface direction of the laminated film 90 can be made uniform. This maximizes the effect of the impact force of the pressurized water W3.

[0029] <Injection section 31> The injection section 31 includes one or more nozzles positioned opposite the backup roller 20, and injects pressurized water from one or more nozzles onto the coating layer 92 of the laminated film 90 as the laminated film 90 passes over the backup roller 20 in order to remove the coating layer 92 of the laminated film 90. When viewed in a cross-section perpendicular to the central axis 20a of the backup roller 20, it is preferable that the central axes of the one or more nozzles of the injection section 31 are perpendicular to the tangent to the outer circumference of the backup roller 20. The injection section 31 is located in the injection chamber 301 and is configured so that the injected water is guided to the second tank 63 of the water recovery and regeneration device 60 via the discharge port 1a. The shape of the nozzle is not particularly limited, but it is preferable that it be a flow-constricting nozzle. A flow-constricting nozzle is 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 nozzle pattern is not particularly limited, but examples include a flat pattern (ejection in a fan shape from the nozzle), a full cone pattern (ejection in a cone shape from the nozzle), and a straight pattern (ejection in a linear shape from the nozzle). Among these, a flat pattern is preferred. As shown in Figure 3, when removing the coating layer using a roll-to-roll method, a flat pattern can break up and remove the coating layer with fewer nozzles and less water compared to a straight pattern.

[0030] <Pressurized Water Supply Unit 50> The pressurized water supply unit 50 pressurizes water and supplies pressurized water W3 to the injection unit 31. 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 first tank 53 for storing water W1 supplied from the water source 55, piping 54 connecting the water source 55 and the first tank 53, and a supply pump 51. The supply pump 51 is connected to tanks 53 and 63 via piping 531 and 631, respectively, and is also connected to the injection unit 31 via piping 511. The second tank 63 stores used and recycled water (also called recycled water W2). In the pressurized water supply unit 50, the water W1 stored in the first tank 53 and the recycled water W2 stored in the second tank 63 are used when generating pressurized water. The supply pump 51 pressurizes water W1 and recycled water W2 and supplies pressurized water W3 to the injection unit 31.

[0031] <Water Recovery and Recycling Device 60> The water recovery and recycling device 60 separates water from the coating layer (desorbed 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 second tank 63, a filtration filter 71, and a recovery pump 61 positioned between the second tank 63 and the filtration filter 71. The second tank 63 is connected to the supply pump 51 via piping 631.

[0032] <Residue Removal Device 70> The residue removal device 70 is a device that removes residue adhering to the base film 91, and 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 examples include a water-draining nozzle (also called an air knife) and a dryer. The residue removal device 70 only needs to be located on the side of the coating layer 92. In the case of Figure 3, the residue removal device 70 is a pair of water-draining nozzles.

[0033] <Winding shaft 40> The winding shaft 40 is located downstream of the backup roller 20 and winds the base film 91, after the coating layer has been removed, into a roll. The winding shaft 40 is connected to a drive roller (not shown).

[0034] 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. For example, the removal method according to the first embodiment comprises, in this order, the ultrasonic application step, the step of preparing a laminated film roll by winding the laminated film after the ultrasonic application step into a roll shape, the step of unwinding the laminated film from the laminated film roll, the removal step, and the substrate recovery step, and the steps from unwinding to the substrate recovery step may be performed roll-to-roll. The removal method according to the first embodiment may also be carried out using a single-sheet laminated film. In this case, the ultrasonic application step is, for example, the step of placing a single-sheet laminated film on a base and impacting the coating layer of the laminated film with a known ultrasonic horn. The coating layer that has cracked or weakened due to the impact can be easily removed by spraying water (preferably pressurized water) using a known method (removal step). In the removal apparatus 100 according to the second embodiment, an example was described in which ultrasonic vibration is applied to the laminated film 90 using one wide ultrasonic horn 81 (see Figure 4) having a length equivalent to the width of the laminated film 90, but the number of ultrasonic horns may be two or more. For example, two or more thin, disc-shaped ultrasonic horns, each shorter than the width of the laminated film, may be arranged axially to create a length equivalent to the width of the laminated film, thereby applying ultrasonic vibration to the laminated film. Alternatively, two or more ultrasonic horns, each having a length equivalent to the width of the laminated film, may be arranged in the direction of transport of the laminated film, thereby applying ultrasonic vibration to the laminated film. In the removal device 100 according to the second embodiment, the case in which the ultrasonic horn 81 is roll-shaped has been described, but the shape of the ultrasonic horn 81 is not limited to a roll shape. The shape of the ultrasonic horn may be a shape that makes contact over a surface, and examples of shapes for ultrasonic horns that make contact over a surface include prismatic, conical, and pyramidal shapes.

[0035] The structure of the laminated film will be explained.

[0036] [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.

[0037] <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.

[0038] 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.

[0039] <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.

[0040] (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.

[0041] In a release agent composition mainly composed of a silicone-based compound, examples of the silicone-based compound include a silicone-based compound having 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.

[0042] 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.

[0043] In a release agent composition mainly composed of a long-chain alkyl group-containing compound, examples of the long-chain alkyl group-containing compound include polyvinyl carbamate obtained by reacting a long-chain alkyl isocyanate with a polyvinyl alcohol polymer, alkylurea derivatives obtained by reacting a long-chain alkyl isocyanate with polyethyleneimine, or copolymers of long-chain alkyl (meth)acrylates. Furthermore, a long-chain alkyl-modified alkyd resin obtained by a condensation reaction of a polyhydric alcohol and a polybasic acid, using a long-chain fatty acid as a modifying agent, may also be used.

[0044] Preferably, the release agent composition mainly composed of an energy-ray curable resin contains, for example, 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. In the release agent layer formed by this release agent composition, since the energy-ray curable compound and the polyorganosiloxane have different molecular structures, polarities, and molecular weights, components derived from the polyorganosiloxane segregate near the outer surface of the release agent layer before curing, and then the segregation is fixed by curing with energy rays. This improves the release properties of the release agent layer. The release agent composition mainly composed of an energy-ray curable resin may further contain a photopolymerization initiator.

[0045] Examples of the release agent composition mainly composed of a thermosetting resin include a release agent composition mainly composed of a melamine resin and a release agent composition mainly composed of an epoxy resin. Examples of the release agent composition mainly composed of a melamine resin include a composition containing a melamine resin as the main agent, an acid catalyst for thermally curing the melamine resin, and a polyorganosiloxane that imparts releasability to the release agent layer. Examples of the release agent composition mainly composed of an epoxy resin include a composition containing an epoxy resin as the main agent, an acidic or basic thermosetting catalyst for thermally curing the epoxy resin, and a polyorganosiloxane that imparts releasability to the release agent layer. Before curing, the components derived from the polyorganosiloxane are segregated near the outer surface of the release agent layer, and then cured to fix the segregation. Thereby, the releasability of the release agent layer can be improved.

[0046] In addition, the coating layer may contain other additives in addition to the resin components described above. Examples of other additives include antioxidants, light stabilizers, flame retardants, conductive agents, antistatic agents, and plasticizers.

[0047] The thickness of the coating layer can be appropriately selected and is not particularly limited. For example, it is preferably 0.02 μm or more and 5 μm or less, more preferably 0.03 μm or more and 2 μm or less, and still more preferably 0.05 μm or more and 1.5 μm or less.

[0048] (Ceramic green sheet) The coating layer preferably includes a release agent layer and a ceramic green sheet. In this case, it is preferable that the laminated film has the base film, the release agent layer, and the ceramic green sheet directly laminated in this order.

[0049] 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.

[0050] (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.

[0051] (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.

[0052] (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.

[0053] (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.

[0054] (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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 10...feeding shaft, 20...backup roller, 31...injection unit, 40...winding shaft, 50...pressurized water supply unit, 51...supply pump, 53...first tank, 54...piping, 55...water source, 60...water recovery and recycling device, 61...recovery pump, 63...second tank, 70...residue removal device, 71...filtration filter, 75...residue detection device, 90, 90A...laminated film, 91...base film, 92, 92A...coating layer, 100...removal device, 301...injection chamber, 511, 531, 631...piping, 921...release agent layer, 922...ceramic green sheet, 1a...discharge port, 20a...center axis.

Claims

1. A method for removing a coating layer from a laminated film having a base film and a coating layer, comprising: an ultrasonic application step of applying ultrasonic vibrations to the laminated film to impact the coating layer; and a removal step of spraying water onto the coating layer after the ultrasonic application step to remove the coating layer.

2. The method for removing a coating layer according to claim 1, wherein the ultrasonic application step involves applying ultrasonic vibrations to the laminated film while bringing an ultrasonic horn into contact with the coating layer of the laminated film.

3. The method for removing a coating layer according to claim 2, wherein the ultrasonic application step involves applying ultrasonic vibrations to the laminated film while pressing the laminated film between a backup roller and the ultrasonic horn.

4. A method for removing a coating layer according to claim 1 or claim 2, further comprising: preparing a laminated film roll in which the laminated film is wound in a roll shape; unwinding the laminated film from the laminated film roll; and recovering the base film after the coating layer has been removed in the removal step by winding it into a roll shape, wherein the preparation step, the unwinding step, the ultrasonic application step, the removal step, and the base film recovery step are performed in this order, and the steps from the unwinding step to the base film recovery step are performed roll-to-roll.

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

6. The method for removing a coating layer according to claim 4, further comprising a step of draining the water from the substrate film after the removal step and before the substrate recovery step.

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

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

9. A coating layer removal device for removing a coating layer from a laminated film having a base film and a coating layer, comprising: a feeding shaft for feeding the laminated film from a laminated film roll in which the laminated film is wound in a roll shape; an ultrasonic vibration unit disposed downstream of the feeding shaft and applying ultrasonic vibration to the laminated film to impact the coating layer; a backup roller disposed downstream of the ultrasonic vibration unit and transporting the laminated film downstream; a spray unit including one or more nozzles disposed opposite the backup roller and spraying pressurized water from the one or more nozzles onto the coating layer to remove the coating layer of the laminated film as the laminated film passes the backup roller; a pressurized water supply unit for supplying pressurized water to the spray unit; and a winding shaft disposed downstream of the backup roller and winding the base film after the coating layer has been removed into a roll shape, wherein the pressurized water supply unit includes a pump, and the spray unit is connected to the pump.

10. The coating layer removal apparatus according to claim 9, wherein the ultrasonic vibration unit is an ultrasonic horn.

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