Method for separating coating from film with coating, and apparatus for separating coating

Abstract

The present invention provides: a method for separating a coating, the method being capable of efficiently removing a coating, which contains a water-soluble resin, from the surface of a film with a coating with use of a very small amount of a solvent; and an apparatus for separating a coating. A method for separating a coating from a film with a coating according to the present invention separates a coating from a film with a coating, the film having a coating, which contains a water-soluble resin, on at least one surface of a base material film; and this method is characterized in that a cleaning liquid in the form of droplets is applied to and held on the surface of the coating, and subsequently the coating, which contains the cleaning liquid, is separated from the film with the coating.

Description

Method and apparatus for peeling coating from coated film

[0001] The present invention relates to a method and apparatus for peeling a coating from a coated film, which are capable of efficiently removing a coating from the surface of a thermoplastic resin film.

[0002] While plastics are used in a variety of fields, they are also considered a cause of marine pollution, such as microplastics, making it urgent to reduce the environmental impact of plastics. Furthermore, with the recent advancement of the Internet of Things (IoT), the number of electronic devices, such as CPUs, installed in computers and smartphones has increased, and the number of multilayer ceramic capacitors (MLCCs) required to drive these electronic devices has also increased dramatically. A typical method for manufacturing MLCCs involves using a release film, which has a release layer formed on a plastic substrate film, as a carrier sheet, forming a ceramic green sheet layer on the release film, and peeling the ceramic green sheet layer to obtain a ceramic green sheet. In this process, the release film from which the ceramic sheet has been peeled is discarded as waste.

[0003] That is, the increase in release film waste due to the rapid increase in the production volume of MLCCs in recent years has become an environmental problem, and efforts to reuse base films have been intensified. From the viewpoint of releasability, the components of the release layer contained in a release film generally have a different composition from the components constituting the base film. Therefore, if a release film with a release layer is directly remelted to produce a recycled film, the components of the release layer are present as foreign matter, making stable film production impossible. Patent Document 1 discloses a method for removing release components from a release film, in which a release film having a water-soluble resin layer formed between the base film and the release layer is used, and the film is immersed in a hot water bath for 2 seconds or more, and then the release layer is peeled off by rubbing the surface of the release film with a brush roll.

[0004] Japanese Patent Application Laid-Open No. 2004-363140

[0005] However, the coating peeling method disclosed in Patent Document 1 has the problem that the water-soluble resin layer dissolves in the hot water tank, and as the treatment time passes, the resin concentration in the hot water increases, making it impossible to continue to exhibit the initial peeling ability. Even if a method of increasing the water supply amount is adopted to suppress the increase in resin concentration, the amount of wastewater increases along with the amount of water supply, resulting in problems such as a significant increase in cleaning costs and a significant increase in the environmental load.

[0006] Therefore, the present invention aims to provide a coating peeling method and coating peeling device that can efficiently remove a coating containing a water-soluble resin from the surface of a coated film having a coating containing a water-soluble resin on at least one side of the substrate film by using a very small amount of solvent, in order to obtain a substrate film that can be reliably remelted to form a recycled film after use.

[0007] The coating peeling method of the present invention, which solves the above-mentioned problems, is a method for peeling a coating from a coated film having a substrate film on at least one side thereof with a coating containing a water-soluble resin, by applying a cleaning liquid in the form of droplets to the surface of the coating, allowing the cleaning liquid to remain in droplet form on the surface of the coating, and then peeling the coating containing the cleaning liquid from the coated film. Furthermore, the method for peeling a coated film of the present invention is preferably a method as follows: - The cleaning liquid is applied to the surface of the coating while heated to 40°C or higher. - The coated film is heated to 40°C or higher. - The coating contains a curable silicone resin. - The cleaning liquid is water. - The diameter of the droplets of the cleaning liquid is 1 mm or less.

[0008] The coating peeling device of the present invention, which solves the above-mentioned problems, is a device for peeling a coating from a coated film having a substrate film on at least one side thereof with a coating containing a water-soluble resin, and includes: a cleaning liquid application mechanism that ejects cleaning liquid in droplet form toward the surface of the coating so that the cleaning liquid remains in droplet form on the surface of the coating, and a peeling mechanism that peels the coating containing the cleaning liquid from the coated film with the cleaning liquid applied to the surface of the coating. Furthermore, the coated film cleaning device of the present invention preferably has the following aspects: The cleaning liquid application mechanism includes a means for heating the cleaning liquid. The coated film is also preferably equipped with a means for heating the coated film.

[0009] According to the coating peeling method and coating peeling device of the present invention, a coating containing a water-soluble resin can be efficiently peeled from a coated film having a substrate film on at least one side thereof using a small amount of cleaning liquid.

[0010] 1 is a schematic diagram of a delamination apparatus 101 according to a first embodiment of the present invention; 201 according to a second embodiment of the present invention; 301 according to a third embodiment of the present invention; 401 according to a conventional delamination apparatus; 501 according to an embodiment different from the present invention; and 601 according to an embodiment different from the present invention.

[0011] The present inventors have conducted extensive research into a method for efficiently peeling a coating from the surface of a coated film having a coating containing a water-soluble resin on at least one side of a substrate film using a very small amount of cleaning liquid, and as a result have discovered the following coating peeling method and coating peeling apparatus for a coated film.

[0012] [Target Coated Film] The coating peeling method of the present invention is a method for peeling and removing a coating containing a cleaning liquid from a coated film having a coating containing a water-soluble resin on at least one side of a substrate film.

[0013] The target coated films may be any coated film having a coating containing a water-soluble resin that takes into consideration environmental impact, etc. Among these, the water-soluble resin is preferably one containing at least one of water-soluble polyester resins, polyester urethane resins, acrylic resins, ethylene ionomer resins, polyvinyl alcohol resins, polyvinylpyrrolidone resins, ethylene-vinyl alcohol resins, and starch as the main component. The coating containing a water-soluble resin may be a single layer containing a water-soluble resin, a laminate of two or more layers containing a water-soluble resin, or a laminate of a layer containing a water-soluble resin and a layer not containing a water-soluble resin.

[0014] Furthermore, a coated release film containing a release component in addition to a water-soluble resin in part of the coating is particularly preferred, as it can efficiently achieve the effect of coating peeling. The release component here refers to a component that increases the contact angle of the coating surface with the cleaning liquid, i.e., reduces the surface energy of the coating. Examples include curable silicone resin compounds with a dimethylsiloxane main skeleton, compounds with a long-chain alkyl group, and compounds with fluorine. The coating may be a layer containing a water-soluble resin and a release component, or a layer containing a water-soluble resin and a layer containing a release component may be laminated. In the case of a laminated coating, it is preferable to form a layer containing a water-soluble resin directly on the substrate film, and then a layer containing a release component on the outermost surface. It is particularly preferable to use a curable silicone resin compound with a dimethylsiloxane main skeleton as the release component, which has high water permeability and can be suitably used as a cleaning liquid. [Method for Peeling a Coating from a Coated Film]

[0015] The coating peeling method of the present invention is a peeling method in which a cleaning liquid in the form of droplets is applied to the coating surface of the above-mentioned coated film, the cleaning liquid is retained in the form of droplets on the coating surface, and then the coating containing the cleaning liquid is removed from the substrate film.

[0016] A method of applying a cleaning liquid to the coating surface is easily conceivable, such as applying the cleaning liquid in a planar, i.e., thin film form, as in general coating. However, for coated films in which the surface tension of the coating is lower than that of the cleaning liquid, such as coated films containing a release component in part of the coating, the cleaning liquid is repelled by the coating and flows widely, resulting in uneven distribution of the cleaning liquid and poor coating peeling in areas where the cleaning liquid is not present. On the other hand, according to the present invention, by discretely applying the cleaning liquid to the coating in the form of droplets, even for coated films in which the surface tension of the coating is lower than that of the cleaning liquid, the cleaning liquid applied to the coating surface does not flow and remains in the form of droplets, allowing the cleaning liquid to be applied to almost the entire surface of the coating. The applied cleaning liquid dissolves the water-soluble resin in the coating and diffuses to the surrounding area, spreading the cleaning liquid over the entire surface of the coating. This dissolves the water-soluble resin components over the entire surface of the coating, allowing the coating containing the cleaning liquid to be easily peeled off from the substrate film. Furthermore, even if the coating of the target coated film is a laminated coating containing a release component on the outermost surface, if the release component is a curable silicone resin compound having dimethylchloroethane as its main skeleton, the cleaning solution will permeate from the coating surface and reach the layer containing the water-soluble resin, thereby achieving a similar cleaning effect and allowing the coating to be peeled off.

[0017] The size of the droplets of cleaning solution applied to the surface of the coating may be any size as long as the cleaning solution can be retained discretely on the coating in droplet form, but if the droplet diameter is too large, the droplets may flow due to tilting or vibration of the coated film, and the discretely applied cleaning solution may become unevenly distributed. Therefore, in order to suppress the flow of droplets on the coating, the droplet diameter is preferably 1 mm or less. Furthermore, in order to efficiently clean the entire surface of the coating, for a coated film with a total coating thickness of 1 μm or less, the droplet diameter is preferably 1 mm or less per unit area of ​​1 m. ２ 1cm per ３It is preferable to apply the above-mentioned cleaning solution. By doing so, even if droplets are applied discretely to the coating, the cleaning solution diffuses to the surrounding area while dissolving the water-soluble resin, allowing the coating containing the cleaning solution to be peeled off over almost the entire surface of the coated film. The diameter of the cleaning solution droplets shown here is a value measured by observing and measuring the droplets under a microscope less than one second after the cleaning solution is applied to the coating surface in droplet form. For example, the diameter of the droplets can be easily measured by using a transparent coated film and observing the applied droplets of the cleaning solution from the back side of the film. Furthermore, if more than one second has passed since the cleaning solution was applied to the coating surface in droplet form, the phenomenon of the cleaning solution diffusing while dissolving the water-soluble resin may progress, making measurement difficult.

[0018] In the coating peeling method of the present invention, the higher the temperature of the cleaning solution applied to the coated film, the faster the dissolution rate of the water-soluble resin, i.e., the better the cleaning effect, so the temperature of the cleaning solution applied to the coated film is preferably 40°C or higher. In order to suppress dimensional changes and deterioration of flatness of the substrate film due to heat, the temperature of the cleaning solution applied to the coated film is preferably 150°C or lower. Therefore, the cleaning solution is preferably discharged in the form of droplets whose temperature has been adjusted in accordance with the configuration of the apparatus used, so that the temperature of the cleaning solution and the temperature of the film at the location where the cleaning solution is applied are each in the range of 40°C to 150°C.

[0019] Furthermore, in the coating peeling method of the present invention, increasing the temperature of the coated film can also increase the dissolution rate of the water-soluble resin in the cleaning solution applied to the coating surface, i.e., improve the cleaning effect. Therefore, it is preferable to set the temperature of the coated film to 40°C or higher and 150°C or lower, similar to the temperature of the cleaning solution. The temperature of the coated film shown here is the temperature of the coating surface immediately before the cleaning solution is applied and can be measured using a radiation thermometer or the like. As described above, when the cleaning solution applied to the coated film or the temperature of the coated film is increased, it is preferable that the diameter of the cleaning solution droplets is 10 μm or higher. By doing so, the coating can be cleaned even if part of the cleaning solution evaporates at high temperatures.

[0020] The cleaning solution used in the peeling method of the present invention can be any solvent that can dissolve the water-soluble resin, but water is preferred to reduce the environmental impact. A surfactant or the like may be added to the cleaning solution to improve wettability with the coated film and facilitate the cleaning solution's penetration over the coating surface.

[0021] In the coating peeling method of the present invention, the form of the coated film may be in the form of cut sheets, but it is particularly preferred that the coated film be wound into a roll. By unwinding the rolled coated film, applying the coating peeling method of the present invention, and then winding up the substrate film after the coating has been peeled, the coating peeling process can be carried out continuously and efficiently.

[0022] [Coating Peeling Apparatus for Coated Film] A preferred embodiment of the coating peeling apparatus of the present invention will be described with reference to the drawings. Note that the following description is an example of one embodiment of the present invention, and the present invention is not limited to this, and various modifications are possible within the scope of the spirit of the present invention.

[0023] FIG. 1 is a schematic diagram of a coating peeling apparatus 101 according to a first embodiment of the present invention. The coating peeling apparatus 101 includes an unwinding device 4 that unwinds a coated film 2 and a winding device 5 that winds up the substrate film 3 after the coating has been peeled off. Between the unwinding device 4 and the winding device 5, there are provided a drive device 9 for transporting the coated film 2, a discharge head 6 for applying a cleaning liquid 11 to the coating of the coated film 2, a stripping device 7 for stripping both the cleaning liquid 11 and the coating of the coated film 2, and a drive device 10 for transporting the substrate film 3 after the coating has been peeled off. The discharge head 6, the stripping device 7, and a nozzle 14 (described below) are enclosed in a booth 8. Furthermore, as a cleaning liquid application mechanism, in addition to the discharge head 6, there is provided a liquid delivery pump 12 for delivering the cleaning liquid 11 to the discharge head 6 and a tank (not shown) for storing the cleaning liquid. The discharge head 6 may be a spray nozzle or the like as long as it can discharge the cleaning liquid 11 in droplets and apply it to the coating surface of the coated film 2. The amount of cleaning liquid 11 applied to the coating surface of the coated film 2 is set to 1 cm or more so that the coating containing the water-soluble resin can be sufficiently dissolved. ３ / m ２ It is preferable to be able to do the above, and it is advisable to determine the specifications of the discharge head 6 and the liquid supply pump 12 so that the required amount of cleaning liquid 11 can be applied to the coating surface of the coated film 2 by adjusting the liquid supply pump 12 according to the conveying speed of the coated film 2 and the state of droplets can be maintained.

[0024] The cleaning solution 11 applied to the coating surface of the coated film 2 must dissolve the water-soluble resin contained in the coating before it is transported to the peeling device 7. Specifically, the size of the droplets of the cleaning solution 11 is preferably 1 mm or less in diameter so that they do not flow and fall off the coating surface due to vibrations or tilting of the coated film 2 during transport. Therefore, it is preferable to select a discharge head 6 that can produce droplets with a diameter of 1 mm or less. The discharge head 6 and the peeling device 7 need only be installed facing the coating surface of the coated film 2, and are not limited to being installed on the bottom side as shown in FIG. 1 . Furthermore, it is more preferable that the unwinding device 4 have a mechanism that can switch the unwinding direction of the coated film 2 so that the coating surface of the coated film 2 can be transported facing the discharge head 6 and the peeling device 7, regardless of whether the coating of the rolled coated film 2 is on the inside or outside of the roll.

[0025] The ejection head 6 is preferably capable of ejecting heated cleaning liquid 11 in order to quickly dissolve the water-soluble resin contained in the coating, and is particularly preferably capable of ejecting cleaning liquid 11 heated to 40° C. or higher. The cleaning liquid 11 can be heated by providing a heat source such as a cartridge heater in the ejection head 6, or by heating a tank (not shown) that stores the cleaning liquid, but any means that can heat the cleaning liquid 11 is acceptable and is not limited to these. The material of the ejection head 206 is preferably heat-resistant in order to eject the heated cleaning liquid 11, and metal or heat-resistant resin is preferably used.

[0026] The coating peeling device 101 also includes a hot air generator 13 and a nozzle 14 connected to the hot air generator 13 as heating means for the coated film 2. By using the hot air to raise the temperature of the coated film 2 to 40°C or higher, the cleaning solution 11 applied to the coating surface quickly dissolves the water-soluble resin contained in the coating, allowing the coating to be peeled off more efficiently. The means for heating the coated film 2 may be any means, and is not limited to these, and may include, for example, directly contacting the coated film 2 with a heated roll, or heating using an infrared heater installed in the booth 8.

[0027] The booth 8 of the peeling device 101 is provided to enclose the area from the discharge head 6 to the peeling device 7 in order to prevent the cleaning solution 11 in droplet form from scattering around and to prevent a drop in the temperature of the heated cleaning solution and / or the coated film 2. The material of the booth 8 is preferably heat-resistant because the interior of the booth 8 becomes very hot, and metal, glass, or the like is preferably used.

[0028] In the peeling device 101 according to the embodiment of the present invention, the peeling device 7 is a metal plate with a sharp tip that comes into direct contact with the coated film 2 being conveyed, but the present invention is not limited to this and may be a resin plate with a sharp tip, or a thin metal plate that bends like a blade when pressed against the coated film 2. Alternatively, a mechanism may be provided for rotating a brush roll made of metal or resin in the same direction as the conveyance direction or in the opposite direction, which is brought into direct contact with the coating surface of the coated film 2, or a rag or cloth may be pressed against the coated film 2 to wipe off the coating.

[0029] In the stripping device 101 of the embodiment of the present invention, the smaller the diameter of the droplets of cleaning liquid 11 ejected from the ejection head 6, the more likely they are to scatter to the surrounding area in the section from the ejection head 6 to the stripping device 7, so a booth 8 is provided to surround the section from the ejection head 6 to the stripping device 7.

[0030] The drive devices 9, 10 in the present invention are preferably configured to be able to cut tension so as to stably transport the coated film 2 and the base film 3 from which the coating has been peeled off, but if tension is cut using a suction roll, part of the coating of the coated film 2 may be sucked in, which may cause problems, so a configuration in which a metal drive roll and a rubber roll are used as a nip is more preferred. Furthermore, because the drive devices 9, 10 are likely to be contaminated with the cleaning liquid 11, stainless steel or surface-treated ones are preferably used as rust prevention measures.

[0031] After the coating film wound up by the winding device 5 has been peeled off, it is more preferable to completely remove the cleaning solution 11 from the substrate film 3 so that it can be remelted and stably formed into a recycled film, and a drying device (not shown) may be provided between the peeling device 7 and the winding device 5. The drying device may be provided before winding, and may be located either before or after the drive device 10.

[0032] Furthermore, to check the quality of the base film 3 after the coating has been peeled off, an inspection machine (not shown) that detects coating residues or environmental foreign matter attached during the process may be installed before the winding device 5. The inspection machine may be selected according to the properties of the base film 3, and an inspection machine that uses transmitted light or reflected light is preferably used. Furthermore, a marking device (not shown) for recording the location of coating residues or environmental foreign matter attached during the process detected by the inspection machine may be installed between the inspection machine and the winding device 5. The marking method used by the marking device may be any method that can mark the location of the detected object, such as a pen, sticker, or laser. Marking coating residues or environmental foreign matter attached during the process allows the corresponding locations to be removed before remelting, thereby enabling more stable production of recycled film and preventing deterioration in the quality of the recycled film.

[0033] FIG. 2 is a schematic diagram of a peeling apparatus 201 according to a second embodiment of the present invention. The peeling apparatus 201 includes a non-contact peeling apparatus 207 instead of the peeling device 7 provided in the peeling apparatus 101 according to the first embodiment. The peeling apparatus 201 does not include the hot air generator 13 and the nozzle 14, but may include the hot air generator 13 and the nozzle 14. Other than the above, the peeling apparatus 201 is identical to the peeling apparatus 101 shown in FIG. 1 , and therefore, a description of components common to the peeling apparatus 101 will be omitted. The non-contact peeling apparatus 207 only needs to be able to peel both the cleaning solution 11 and the coating without contact, and examples of such a method include blowing air or blowing the cleaning solution 11. This prevents an increase in conveyance resistance of the coated film 2 and prevents damage to the substrate film 3 due to contact, compared to the peeling apparatus 7 that directly contacts the coating surface.

[0034] 3 is a schematic diagram of a peeling device 301 for peeling a coating from a coated film 302 having coatings on both sides according to a third embodiment of the present invention. Between the unwinding device 4 and the winding device 5, the peeling device 301 is provided with a first discharge head 306 for applying cleaning liquid 11 to one side of the coated surface of the coated film 302, a first peeling device 307 for peeling both the cleaning liquid 11 and the coating, a second discharge head 306' for applying cleaning liquid 11' to the other side of the coated surface, and a second peeling device 307' for peeling both the cleaning liquid 11' and the coating. The second peeling device 307' is provided on the opposite side of the first peeling device 307 across the coated film 302, in direct contact with the coated surface. Furthermore, as a cleaning liquid application mechanism, in addition to the first discharge head 306 and the second discharge head 306', liquid supply pumps 312 and 312' for supplying the cleaning liquids 11 and 11' to the first discharge head 306 and the second discharge head 306', and a tank (not shown) for storing the cleaning liquids 11 and 11' are provided. The peeling device 301 does not include the hot air generator 13 and the nozzle 14, but may include the hot air generator 13 and the nozzle 14. Other than that, the peeling device 301 is the same as the peeling device 101 in FIG. 1 , and therefore a description of the components common to the peeling device 101 will be omitted.

[0035] In the peeling device 301 of this embodiment, cleaning liquids 11 and 11' are applied to the coating surface of a coated film 302 having coatings on both sides simultaneously, and the first peeling device 307 and the second peeling device 307' sequentially peel off both the cleaning liquids 11 and 11' and the coating. However, the present invention is not limited to this configuration, and any configuration may be used as long as the cleaning liquids 11 and 11' and the coating can be peeled off from both the front and back sides. For example, the device may be configured to include a first discharge head 306 and a first peeling device 307, followed by a second discharge head 306' and a second peeling device 307', and peel off both the cleaning liquids 11 and 11' and the coating from each side sequentially. Furthermore, the first peeling device 307 and the second peeling device 307' are not limited to the configuration shown in FIG. 3, and non-contact peeling devices may be used.

[0036] Furthermore, in order to efficiently apply the cleaning solution to the coating surface of the coated film 2, 302, a device for exposing the coating surface of the coated film 2, 302 may be provided between the unwinding device 4 and the driving device 9. For example, when the coating of the coated film 2, 302 is a curable silicone resin compound having dimethylsiloxane as its main skeleton, the coated film is suitable for use as a process release film due to its surface free energy characteristics. Specifically, the coated film is used as a release film for removing a release object in a desired shape after providing the release object on the coating of the coated film. Since the release object may remain on the coating surface of the coated film after being used as such a process release film, it is preferable to provide a device for exposing the coating surface of the coated film between the unwinding device 4 and the driving device 9 to expose the coating surface of the coated film 2, 302. The device for exposing the coating surface may be contact or non-contact, and is selected appropriately depending on the remaining state of the release object. The material to be released is selected appropriately depending on the properties of the coating, but examples include inorganic materials such as metals applied by vapor deposition, adhesives made of organic materials such as acrylics applied by coating, and ceramic green sheets whose main component is barium titanate.

[0037] The present invention will be described below with reference to examples, but the present invention is not necessarily limited to these examples.

[0038] <Coated film> A coated film was produced by forming a 0.1 μm thick film of polyvinyl alcohol resin as a water-soluble resin on a 30 μm thick polyethylene terephthalate substrate film, and further forming a 0.1 μm thick film of curable silicone resin as a release component on top of that.

[0039] <Peeling Evaluation Method> Peeling was evaluated using a commercially available dyne pen (surface energy: 30, 70 mN / m) by the following method. When a drawing was made on a sample surface with a dyne pen at room temperature (23°C) and the state was maintained for 4 seconds or more, it was determined that the surface energy of the sample surface was higher than that of the dyne pen. If the curable silicone resin release component of the coated film remained on the surface, the surface energy was less than 30 mN / m, and therefore the reagent was repelled from the sample surface with either dyne pen, making it impossible to maintain the drawing. On the other hand, when the coating of the curable silicone resin release component was peeled off and the polyvinyl alcohol resin was exposed, the surface energy was 70 mN / m or more, and therefore both dyne pens were able to maintain the drawing. When both the release component coatings of the curable silicone resin and the water-soluble polyvinyl alcohol resin are peeled off and the polyethylene terephthalate is exposed, the surface energy is 43.8 mN / m, so that a 30 mN / m dyne pen drawing is maintained, but a 70 mN / m dyne pen drawing is not maintained. Using the above evaluation method, it was determined whether or not the coating of the coated film was peeled off.

[0040] <Removal of Coating from Coated Film> [Example 1] A coated film 2 was set in the unwinding device 4 of the peeling device 101 shown in Figure 1. The coated film was transported to the booth 8 by the drive device 9, while water (room temperature: 20°C) was applied in droplets as a cleaning liquid 11 to the coating surface from a spray nozzle (1 / 4M KB 80063N S303-RW, manufactured by Ikeuchi Co., Ltd.) on the discharge head 6 inside the booth 8. The droplets of cleaning liquid 11 applied to the coating surface were then peeled off from the substrate film 3 by contacting a sharp-tipped SUS630 plate with the coated film in the peeling device 7, and the cleaning liquid 11 and coating were then taken up by the winding device 5. The transport speed was increased from 10 m / min to 10, 30, 50, and 100 m / min. In Example 1, the coated film 2 was not heated by the hot air generator 13 and the nozzle 14. The cleaning solution 11 discharged from the spray nozzle was delivered from a Mohno pump (CY08, Heishin Soubi Co., Ltd.). The amount of solution delivered was adjusted according to the conveying speed. At any conveying speed, the amount of solution delivered was equal to the unit area of ​​1.0 m of the coated film 2. ２ 30cm per ３ The droplets of cleaning liquid 11 applied to the coated film 2 were observed from the backside, and it was confirmed that the maximum diameter of the droplets was 1 mm. The temperature of the coated film 2 was measured from the backside of the coated film 2 immediately after the droplets were applied using a radiation thermometer, and was found to be 20°C. When the substrate film 3 from which the coating had been peeled after being taken up by the winding device 5 was sampled, the maximum conveying speed at which both the curable silicone resin and water-soluble polyvinyl alcohol resin coatings of the release components could be peeled off was 30 m / min. At conveying speeds of 50 and 100 m / min higher, peeling evaluation confirmed that part of the curable silicone resin or polyvinyl alcohol resin coating remained.

[0041] Example 2 The procedure of Example 1 was repeated, except that the cleaning liquid 11 discharged from the spray nozzle (1 / 4M KB 80063N S303-RW, manufactured by Ikeuchi Co., Ltd.) was changed to 50°C water. The temperature of the 50°C water was adjusted by adding a throw-in heater to a tank storing the cleaning liquid 11, and the water was delivered to the spray nozzle 6 using a liquid delivery pump 12. Furthermore, droplets of the cleaning liquid 11 applied to the coated film 2 were observed from the backside, and it was confirmed that the maximum diameter of the droplets was 1.0 mm. The temperature of the coated film 2 was measured from the backside of the coated film 2 immediately after the droplets were applied using a radiation thermometer, and was found to be 40°C. After being wound up by the winding device 5, the substrate film 3 from which the coating had been peeled was sampled, and the maximum conveying speed at which both the release component curable silicone resin coating and the water-soluble polyvinyl alcohol resin coating could be peeled off was 50 m / min. At a conveying speed of 100 m / min, peeling evaluation confirmed that part of the curable silicone resin or polyvinyl alcohol resin coating remained.

[0042] Example 3 The procedure of Example 2 was carried out, except that the temperature of the cleaning liquid 11 in Example 2 was changed to water at 90°C. Furthermore, droplets of the cleaning liquid 11 applied to the coated film 2 were observed from the backside, and it was confirmed that the maximum diameter of the droplets was 1.0 mm. The temperature of the coated film 2 was measured from the backside of the coated film 2 immediately after the droplets were applied using a radiation thermometer, and was found to be 75°C. The substrate film 3 from which the coating had been peeled after being wound up by the winding device 5 was sampled, and it was found that the maximum conveying speed at which both the curable silicone resin and water-soluble polyvinyl alcohol resin coatings, which were release components, could be peeled off was 100 m / min.

[0043] Example 4 The same procedure as in Example 1 was carried out, except that in the peeling device 101 of Example 1, hot air (60°C) generated using a hot air generator 13 (TSK-56 manufactured by Kansai Electric Heating Co., Ltd.) was blown from a nozzle 14 having a slit-shaped opening onto the back surface of the coated film 2 substantially simultaneously with the application of the droplets. Furthermore, the droplets of cleaning solution 11 applied to the coated film 2 were observed from the back surface, and it was confirmed that the maximum diameter of the droplets was 1.0 mm. The temperature of the coated film was measured using a radiation thermometer from the back surface of the coated film 2 immediately after the application of the droplets and the blowing of the hot air, and was found to be 40°C. The substrate film 3 from which the coating had been peeled after being wound up by the winding device 5 was sampled, and the maximum conveying speed at which both the release component curable silicone resin coating and the water-soluble polyvinyl alcohol resin coating could be peeled off was 50 m / min.

[0044] Comparative Example 1: A coating was peeled from a coated film 2 using a conventional peeling apparatus 401 shown in Figure 4. The peeling apparatus 401 includes a water tank 414 containing water, which serves as cleaning solution 11, an adjacent drainage tank 415 so that the liquid level in the water tank 414 overflows and is drained, and a filtration filter 416 for separating the peeled coating from the drainage. The coated film 2 was set in the unwinding device 404 of the peeling apparatus 401, transported to the water tank 414 by a drive device 409, and brought into contact with water (room temperature: 20°C), which serves as cleaning solution 11. The film was then brought into contact with a sharp-tipped SUS630 plate by a peeling device 407, which peeled off both the cleaning solution 11 and the coating. The substrate film 3 from which the coating had been peeled was then wound up by a winding device 405. The amount of new cleaning solution 11 to be supplied to the water tank 414 was determined based on the minimum amount required while monitoring the peeling status of the coating. As the water-soluble polyvinyl alcohol resin contained in the coating dissolves and the concentration of the solution increases, the elution of the polyvinyl alcohol resin decreases. Therefore, in order to continuously peel off the coating, the unit area (1 m) of the coated film must be increased. ２ ) per 25,000 cm ３It was necessary to send a cleaning solution 11 of 100 m / min. When the substrate film 3 from which the coating had been peeled after being taken up by the winding device 405 was sampled, the maximum conveying speed at which both the curable silicone resin and water-soluble polyvinyl alcohol resin coatings, which are release components, could be peeled off was 50 m / min. At a conveying speed of 100 m / min, peeling evaluation confirmed that part of the curable silicone resin and polyvinyl alcohol resin coatings remained.

[0045] Comparative Example 2: The coating of the coated film 2 was peeled using the peeling device 501 shown in FIG. 5 . The peeling device 501 was equipped with a pressure device 512 and a discharge head 506 for discharging water, which served as the cleaning solution 11, at high pressure. The same procedure as in Example 1 was repeated, except that the pressure device 512 and the discharge head 506 were used to provide the cleaning solution 11 as high-pressure water instead of the spray nozzle 6 used in Example 1, and the conveyance speed was limited to 50 m / min. High-pressure water (room temperature: 20°C) was discharged from the attached discharge head 506 using the pressure device 512 (a high-pressure washer K2 Classic manufactured by Kärcher Japan Co., Ltd.) toward the coating surface of the coated film 2. Because the cleaning solution 11 was continuously discharged at high pressure and in large quantities to maintain the high pressure, it did not form droplets even when it adhered to the coated film 2, but instead dripped from the entire surface of the coated film 2. Furthermore, a large amount of cleaning water 11 splashed off the surface of the coated film 2 and accumulated in the booth 8. The temperature of the coated film 2 was measured using a radiation thermometer from the backside of the coated film 2 immediately after the application of the cleaning solution 11, and was found to be 20° C. The substrate film 3 from which the coating had been peeled after being wound up by the winding device 5 was sampled to check the amount of high-pressure water required to peel off both the curable silicone resin and water-soluble polyvinyl alcohol resin coatings, which are the release components. ２ per 800 cm ３ The amount of high-pressure water was determined by recovering the coating containing the cleaning liquid 11 peeled off by the peeling device 7 and the cleaning liquid 11 accumulated in the booth, calculating the amount of cleaning liquid 11 from the weight measurement results, and converting it into a value per unit area of ​​the coated film 2.

[0046] Comparative Example 3 Peeling of the coating from the coated film 2 was carried out using a peeling device 601 shown in FIG. 6 . The peeling device 601 was equipped with a steam generator 612 and a discharge head 606 for discharging water, the cleaning liquid 11, in the form of steam. The same procedure as in Example 1 was carried out, except that the cleaning liquid 11 was steamed using the steam generator 612 and the discharge head 606 instead of the spray nozzle 6 used in Example 1, and the conveying speed was limited to 30 m / min. Steam was discharged from a discharge head (φ10 opening nozzle) using a steam generator (BOILER.V manufactured by Nippon Dentsu Co., Ltd.) toward the coating surface of the coated film 2. Because the discharged steam was a large amount with a discharge temperature of 100°C and a discharge pressure of 0.4 MPa, it was observed that the droplets did not remain in droplet form even when attached to the coated film 2, but rather quickly combined into droplets exceeding 1 mm in size, which then flowed down from the surface of the coated film 2. It was also confirmed that where droplets of more than 1 mm had flowed out, there were areas where no cleaning liquid 11 remained. Furthermore, a large amount of cleaning liquid 11 had flowed down from the surface of the coated film 2 and accumulated in the booth 8. When the amount of cleaning liquid 11 used was measured, it was found that the amount of cleaning liquid 11 remaining was 1.0 m per unit area of ​​the coated film 2. ２ per 200 cm ３ It was confirmed that the amount of cleaning liquid 11 used for steaming was determined by recovering the coating containing the cleaning liquid 11 peeled off by the peeling device and the cleaning liquid 11 accumulated in the booth, calculating the amount of cleaning liquid 11 from the weight measurement results, and converting it into a value per unit area of ​​the coated film 2. The temperature of the coated film 2 was measured using a radiation thermometer from the back side of the coated film 2 immediately after application of the cleaning liquid 11, and was found to be 85°C. Similarly, the temperature of the film was measured at the portion where droplets exceeding 1 mm had flowed off, and was found to be 50°C. The substrate film 3 from which the coating had been peeled after being wound up by the winding device 5 was sampled and subjected to a peeling evaluation, and it was confirmed that there were portions of the curable silicone resin and polyvinyl alcohol resin coatings remaining in the portions of the surface of the coated film 2 where droplets exceeding 1 mm had flowed off.

[0047]

[0048] Comparison of Examples 1 to 4 with Comparative Examples 1 to 3 Examples 1 to 4 of the present invention were able to significantly reduce the amount of cleaning liquid used per unit area compared to Comparative Example 1, which used a conventional stripping device 401; Comparative Example 2, which used a high-pressure cleaning liquid with stripping device 501; and Comparative Example 3, which used steam injection with stripping device 601. Therefore, in Examples 1 to 4, the amount of wastewater was significantly reduced, thereby reducing the environmental impact and keeping cleaning costs low. Furthermore, in Comparative Example 3, it was confirmed that droplets flowed off the surface of the coated film, and that portions of the coating remained where the droplets flowed off. This demonstrates that, in order to strip the coating, it is important to retain the droplets on the surface of the coated film, as in Examples 1 to 4.

[0049] [Comparison of Examples 1, 2, and 3] In Example 2, by heating the cleaning solution to 50°C, the conveying speed at which the coating of the coated film could be peeled could be increased compared to Example 1, where the cleaning solution temperature was 20°C, and the coating could be peeled even at a maximum conveying speed of 50 m / min. In Example 3, by heating the cleaning solution to 90°C, the conveying speed at which the coating of the coated film could be peeled could be further increased, and the coating could be peeled even at a conveying speed of 100 m / min.

[0050] Comparison of Examples 1, 2, and 4 In Example 2, where the temperature of the cleaning solution was raised to 50°C and the temperature of the coated film was raised to 45°C, and in Example 4, where the cleaning solution was applied at room temperature (20°C) and the temperature of the coated film was raised to 40°C, the maximum conveying speed at which the coating could be peeled from the coated film was equivalent, at 50 m / min. In both coated film heating methods, by raising the temperature of the coated film to 40°C, the conveying speed at which the coating could be peeled could be increased compared to Example 1, where the temperature of the coated film was raised to room temperature (20°C).

[0051] The coated film peeling method and peeling device of the present invention can be suitably used for recycling films having a release layer. The coated film that can be applied to the coated film peeling method and peeling device of the present invention is not limited to a film having a coating containing a water-soluble resin on one side of a base film, but may be a recyclable resin film, paper film, or metal film having a coating containing an easily soluble resin layer.

[0052] DESCRIPTION OF SYMBOLS 2 Coated film 3, 303 Base film 4, 404 Unwinding device 5, 405 Winding device 6, 506 Discharge head 7, 407 Peeling device 8 Booth 9, 10, 409, 410 Drive device 11, 11' Cleaning liquid 12, 412 Liquid supply pump 13 Hot air generator 14 Nozzle 101, 201, 301 Peeling device 207 Non-contact peeling device 302 Double-sided coated film 306 First discharge head 306' Second discharge head 307 First peeling device 307' Second peeling device 312 First liquid supply pump 312' Second liquid supply pump 401 Conventional peeling device 414 Water tank 415 Drain tank 416 Filtration filter 417 Guide roll 512 Pressurizing device

Claims

1. A method for peeling a coating from a coated film having a coating containing a water-soluble resin on at least one surface of a substrate film, comprising the steps of: Applying a cleaning liquid in droplets to the surface of the coating, and allowing the cleaning liquid to be held in droplets on the surface of the coating; Next, the coating containing the cleaning solution is peeled off from the coated film. A method for removing a coating from a coated film.

2. A method for peeling a coating from a coated film as described in claim 1, wherein the cleaning solution is applied by using a spray nozzle.

3. 3. The method for peeling a coating from a coated film according to claim 1, wherein the cleaning liquid is applied to the surface of the coating in a state where the cleaning liquid is heated to 40° C. or higher.

4. The method for peeling a coating from a coated film according to any one of claims 1 to 3, wherein the coated film is heated to 40°C or higher.

5. The method for peeling a coating from a coated film according to any one of claims 1 to 4, wherein the coating comprises a curable silicone resin.

6. The method for peeling a coating from a coated film according to any one of claims 1 to 5, wherein the cleaning liquid is water.

7. The method for peeling a coating from a coated film according to any one of claims 1 to 6, wherein the diameter of droplets of the cleaning liquid is 1 mm or less.

8. An apparatus for peeling a coating from a coated film having a coating containing a water-soluble resin on at least one surface of a base film, comprising: a cleaning liquid applying mechanism that ejects the cleaning liquid in droplets toward the surface of the coating so that the cleaning liquid can be maintained in the form of droplets on the surface of the coating; a peeling mechanism for peeling off the coating containing the cleaning liquid from the coated film having the cleaning liquid applied to the surface of the coating; An apparatus for peeling a coating from a coated film comprising:

9. The apparatus for peeling a coating from a coated film as described in claim 8, wherein the cleaning liquid application mechanism is a spray nozzle.

10. 10. The apparatus for peeling a coating from a coated film according to claim 8, wherein the cleaning liquid applying mechanism comprises a means for heating the cleaning liquid.

11. 11. The apparatus for peeling a coating from a coated film according to claim 8, further comprising a means for heating the coated film.