Apparatus for peeling a coating from a coated film, peeling method, and method for manufacturing a substrate film from which the coating has been peeled off.

Abstract

To provide a coat peeling device that can peel a coat from a surface of a film with the coat without using water or other solvents or without increasing an environmental load.SOLUTION: A coat peeling device of the present invention is a device for peeling a coat from a film with the coat having the coat on at least one side of a base film, and is arranged to face a surface having the coat, of the film with the coat, and includes a nozzle that sprays, onto the coat, particles made of dry ice, ice, or a material contained in the base film together with compressed air.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a peeling apparatus and a peeling method capable of efficiently removing a coating from a coated film having a coating on at least one side of a base film, and to a method for producing a base film from which the coating has been peeled by peeling the coating from the coated film using the peeling method.

Background Art

[0002] While plastics are used in various fields, they are considered as a causative agent of marine pollution such as microplastics, and reducing the environmental load caused by plastics has become an urgent issue.

[0003] Furthermore, in recent years, with the advancement of the Internet of Things (IoT), the number of electronic devices such as CPUs mounted in computers and smartphones has increased, and accordingly, the number of multilayer ceramic capacitors (MLCCs) required to drive electronic devices has also increased sharply. A general manufacturing method for this MLCC includes the steps of: using a release film obtained by forming a release layer on a plastic base 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.

[0004] In this step, the release film from which the ceramic sheet has been peeled is discarded as an unnecessary material. That is, the increase in waste release film accompanying the rapid increase in the quantity of MLCCs in recent years has become an environmental problem, and efforts toward the reuse of plastic base films have become active.

[0005] To reuse discarded release films, a recycled film may be obtained by collecting / crushing / processing into resin chips, then remelting and forming the film.

[0006] However, the components of the release layer contained in the release film generally have a different composition from the components that make up the base film, from the standpoint of release properties. Therefore, when a release film with a release layer attached is crushed into resin chips and then remelted to form a film, the components of the release layer are present as foreign matter, making it difficult to form a stable film.

[0007] Furthermore, even if a film can be produced, the resulting film will inevitably deteriorate in quality due to the presence of the release layer as a foreign substance, resulting in discoloration of the film and changes in its surface composition. Therefore, it cannot be restored to a film of the same quality as the original substrate film.

[0008] Therefore, in order to recycle release film as recycled film, it is necessary to remove the components of the release layer contained in the release film to a level of trace residue that does not pose a problem for the quality of recycled film.

[0009] Ideally, the process of recovering, crushing, and obtaining high-purity resin chips, then remelting and recycling them as recycled film, should be carried out in a low-cost, long-term circular manner without increasing the environmental burden. However, achieving this is extremely difficult.

[0010] Patent Document 1 discloses a method for removing release components from a release film, which involves using a release film in which a water-soluble resin layer is formed between a base film and a release layer, immersing it in a hot water bath for 2 seconds or more, and then peeling off the release layer by rubbing the surface of the release film with a brush roll. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2004-363140 [Overview of the project] [Problems that the invention aims to solve]

[0012] The method disclosed in Patent Document 1 uses hot water, which generates a large amount of waste liquid in which the water-soluble resin layer has dissolved. Disposing of this waste liquid itself leads to environmental pollution and is recognized as increasing the environmental burden, which clearly contradicts the concept of recycling.

[0013] Furthermore, there is the problem that costs will inevitably increase because disposal will incur expenses.

[0014] To achieve low costs, increasing the processing speed is highly effective. However, in the method disclosed in Patent Document 1, increasing the processing speed is expected to shorten the contact time in the hot water bath to less than 2 seconds. Therefore, in order to maintain contact for more than 2 seconds in the hot water bath, it is necessary to enlarge the hot water bath and increase the path length. This leads to the problem that the amount of waste liquid containing dissolved water-soluble resin layers will increase, further increasing the environmental burden.

[0015] Therefore, the present invention provides a coating removal apparatus and a coating removal method that can remove a coating from the surface of a coated film without using a solvent such as water, and without increasing the environmental burden. [Means for solving the problem]

[0016] The present invention, which solves the above problems, is a device for peeling a coating from a coated film having a coating on at least one side of a base film, The above-mentioned coated film is equipped with a nozzle positioned opposite the surface having the coating, which sprays compressed air together with dry ice, ice, or particles composed of materials contained in the base film toward the coating. However, the coating peeling apparatus of the present invention does not include a coated film.

[0017] The present invention, which solves the above problems, is a method for peeling a coating from a coated film having a coating on at least one side of a base film, Particles composed of dry ice, ice, or a material contained in the base film are sprayed together with compressed air toward the coating of the coated film to peel the coating off from the coated film.

[0018] In the coating peeling method of the present invention, it is preferable that the particles sprayed together with compressed air remove a part of the base film.

[0019] The method for producing a base film from which a coating has been peeled according to the present invention uses the coating peeling method from a coated film of the present invention, and obtains the base film by peeling the coating from a coated film having a coating on at least one surface of the base film.

Effects of the Invention

[0020] By using the coating peeling apparatus and peeling method from a coated film of the present invention, the coating can be peeled from the surface of the coated film without using a solvent such as water and without increasing environmental load.

Brief Description of Drawings

[0021] [Figure 1] It is a schematic diagram of the peeling apparatus 1 of the present invention.

Mode for Carrying Out the Invention

[0022] The inventors of the present invention have intensively studied a method capable of peeling a coating without using a solvent such as water and without increasing environmental load, and as a result, have found the following coating peeling apparatus and peeling method from a coated film.

[0023] [Target Coated Film] The coating peeling apparatus and peeling method for a coated film of the present invention are intended for peeling and removing the coating from the base film, targeting a coated film having a coating on the surface of a base film. The coating may be provided on one surface or both surfaces of the base film, and is not particularly limited.

[0024] The materials constituting the coating can be appropriately selected and used depending on the purpose and application of the coated film.

[0025] When imparting release properties, such as in a release film, it is preferable to include a release component in a part of the coating. The release component referred to here is a component that increases the contact angle with water on the surface of the coating, that is, reduces the surface energy of the coating. For example, curable silicone resin compounds with dimethylsiloxane as the main skeleton, compounds having long-chain alkyl groups, and compounds having fluorine are preferred.

[0026] Depending on the required function, the coating may consist of a mixture of release agents and other different components, or the layers may be laminated. In the case of laminated coatings, it is preferable to form a layer containing a release agent on the outermost surface in order to exhibit the release effect.

[0027] The layer containing the release component is generally a thin film; for example, the release film used in MLCCs is often a coating with a thickness of 1 μm or less.

[0028] The resin used to make up the base film can be made from polyester, polyimide, polypropylene, polyamide, polycarbonate, polyacetate, polyethylene, or the like. In particular, polyester mainly composed of polyethylene terephthalate or polyethylene naphthalate is preferred because it has excellent quality stability after recycling, and for release films, a thickness of several tens of micrometers is used.

[0029] [Apparatus for peeling coatings from coated films] A preferred embodiment of the coating removal device (hereinafter referred to as the coating removal device) from a coated film of the present invention will be described with reference to the drawings. The following description illustrates one embodiment of the present invention and is not limited thereto; various modifications are possible without departing from the spirit of the present invention.

[0030] Figure 1 is a schematic diagram of the coating removal apparatus of the present invention. As shown in Figure 1, the coating removal apparatus 1 is equipped with an unwinding device 4 for unwinding the coated film 2 and a winding device 5 for winding up the base film 3 after the coating has been removed. Between the unwinding device 4 and the winding device 5 are a drive device 6a for transporting the coated film 2, a blasting mechanism 14 for removing the coating from the coated film 2, and a drive device 6b for transporting the base film 3 after the coating has been removed.

[0031] The blasting mechanism 14 includes a nozzle 11 positioned opposite the coated surface of the coated film 2, which sprays compressed air along with particles 10 composed of dry ice, ice, or materials contained in the base film toward the coating.

[0032] The dimensions of the particles 10 supplied from the supply pipe 12 to the nozzle 11 along with compressed air are appropriately selected within the range of 0.1 to 5 mm, depending on the thickness and hardness of the coating, etc., when the particles 10 are dry ice or ice. Since the particles 10 are formed by crushing blocks of dry ice or ice, their shape is not necessarily circular, and depending on the crushing method, they are often in the shape of roughly cylindrical pellets, and the particle dimensions refer to the height dimension of the cylinder.

[0033] Similarly, if the particles 10 are composed of materials contained in the base film, the dimensions of the particles 10 supplied from the supply pipe 12 to the nozzle 11 are appropriately selected within the range of 0.1 to 5 mm, depending on the thickness and hardness of the coating. The particle shapes can be approximately spherical or polygonal, and the shape that allows for the most efficient removal of the coating should be appropriately selected.

[0034] The material of particle 10 is not particularly limited as long as it is a material contained in the base film, but for example, in the case of polyethylene terephthalate film, it is preferable to use particles composed of polyethylene terephthalate, which is the main component. Furthermore, if the base film contains multiple materials, selecting particles made of the material with the highest hardness among them will allow for efficient peeling of the coating.

[0035] The nozzle 11 is positioned so that the particles 10 hit the entire width of the coated film 2 being conveyed. If the width of the coated film 2 is greater than the area to which the particles 10 hit, a mechanism (not shown) can be provided to move the nozzle 11 back and forth in the width direction of the coated film 2, or multiple nozzles 11 can be provided in the width direction.

[0036] Conditions for increasing peeling efficiency, focusing on each individual particle, include increasing the force acting perpendicular to the coating on the particle and increasing the relative velocity with respect to the coated film. To achieve both conditions, it is preferable to set the angle θ between the spray direction of the nozzle 11 and the surface of the coating on the coated film 2 within the range of 30 to 90°. If θ exceeds 90°, both the force acting perpendicular to the coating on the particle and the relative velocity decrease, making it easier for peeling efficiency to decrease. On the other hand, if θ is less than 30°, the relative velocity increases, but the force acting perpendicular to the coating on the particle decreases, making it easier for peeling efficiency to decrease.

[0037] The distance between the nozzle 11 and the coated film 2 is not particularly limited as long as the coating can be peeled off, but generally, a closer distance is preferable because the particles will collide with the coating while maintaining their velocity during spraying, thus enabling more efficient peeling of the coating.

[0038] Furthermore, if the transport speed of the coated film 2 is high, the number of particles that collide per unit area of ​​the coating decreases, so it is preferable to provide multiple nozzles 11 in the transport direction of the coated film 2.

[0039] The cover 13 is for preventing particle scattering and can be installed as needed. Alternatively, a particle collection mechanism (not shown) may be provided inside the cover 13 to collect scattered particles for reuse.

[0040] The coating removal device 1 of this embodiment is intended for coated films having a coating on only one side of the base film, so the nozzle 11 is provided facing only one surface of the coated film. However, if the device is intended for coated films having a coating on both sides of the base film, the nozzle 11 should be provided facing both sides of the coated film.

[0041] [Method for removing the coating from a coated film] The present invention provides a method for removing a coating from a coated film (hereinafter referred to as the coating removal method), The coating on the coated film 2 is peeled off by spraying compressed air along with dry ice, ice, or particles composed of materials contained in the base film onto the coating.

[0042] A commonly used stripping method is sandblasting, which uses particles made of metal or ceramic. When sandblasting is applied to strip the coating from a coated film, the metal or ceramic particles become embedded in the base film and remain as foreign matter. Therefore, when this stripped base film is reused to obtain a recycled film, the resulting film is of lower quality compared to the original base film. It is also conceivable to wash away the embedded particles with a liquid such as water, but this generates wastewater, increasing the environmental burden and contradicting the concept of recycling.

[0043] On the other hand, in the coating removal method of the present invention, since the particles are dry ice or ice, the particles evaporate and disappear after the coating is removed. As a result, there is no particle residue on the substrate film after removal, making it possible to regenerate the film to a quality level equivalent to the original substrate film. Furthermore, since washing with liquids such as water is unnecessary, there is no increase in environmental burden. In particular, dry ice is often produced by recycling CO2 emitted from factories and other sources, making it suitable from the viewpoint of environmental impact.

[0044] If the particles are composed of materials contained in the base film, even if the particles remain embedded in the base film when the coating is peeled off, they cannot become foreign matter, making it possible to regenerate the film to a quality level equivalent to the original base film.

[0045] For example, if the base film is a polyethylene terephthalate film, then particles composed of polyethylene terephthalate, the main component, should be used.

[0046] Furthermore, it is preferable that the particles composed of the material contained in the base film be made of a high-purity material free of foreign matter. For example, if the coated polyethylene terephthalate film before peeling has a level of foreign matter residue that does not pose a quality problem, using high-purity polyethylene terephthalate particles free of foreign matter will cause the coating to peel off, and the particles will remain embedded in the base film, increasing the concentration of polyethylene terephthalate, and thus decreasing the concentration of foreign matter. Therefore, the recycled film obtained in this way can be expected to have improved quality compared to the polyethylene terephthalate film before peeling.

[0047] When peeling off a coating, it is desirable to reduce the amount of residue left behind as foreign matter to zero or as little as possible. To achieve this, it is preferable that more particles reach the surface layer of the base film located at the interface with the coating, and as a result, that the particles remove a portion of the base film.

[0048] The particles peel off the coating and simultaneously remove the surface layer of the base film located at the interface with the coating, ensuring reliable coating removal and obtaining a base film free of residue.

[0049] To achieve these goals, it is preferable to install multiple nozzles in the film transport direction to cause many particles to collide with the coating. For example, by spraying dry ice or ice from a nozzle located upstream in the transport direction, and spraying particles composed of materials contained in the base film from a nozzle located downstream, it is possible to remove a portion of the base film along with the coating, while, as mentioned above, particles composed of materials contained in the base film remain on the base film, thus improving the quality of the recycled film.

[0050] Furthermore, as long as the particles used consist of dry ice, ice, or materials contained in the base film, there are no particular limitations on the combination of particles or the number of nozzles; they should be determined as appropriate based on the required amount of residue.

[0051] In addition, regardless of the number of nozzles, the shape, size, and spray volume of the particles may be changed, or the spraying speed may be increased, to inflict more damage on the coated film.

[0052] [Method for manufacturing release film] The present invention's method for manufacturing a release film (hereinafter referred to as the manufacturing method) involves using the aforementioned release film method to remove the coating from a coated film having a coating on at least one side of the base film, thereby obtaining a base film.

[0053] By using the manufacturing method of the present invention, the substrate film from which the coating has been peeled off can be recovered, crushed, and high-purity resin chips obtained, and then remelted to obtain recycled film. This allows for low-cost, long-term recycling without increasing the environmental burden. In particular, it is especially effective when used as a release film for MLCCs and the like. [Industrial applicability]

[0054] The coated film to which the coating device and method for releasing coated films of the present invention can be applied is not limited to, but can be a recyclable resin film having a coating on one side of a base film, a paper film, a metal film, and the like.

[0055] Furthermore, the film peeling apparatus and peeling method for coated films of the present invention can be used not only to peel the coating from used coated films that have been used once in the manufacturing process of MLCCs, but also to peel the coating from unused coated films. [Explanation of Symbols]

[0056] 1 Film stripping device 2. Coated film 3. Base film 4 Unwinding device 5 Winding device 10 particles 11 nozzles 12 Supply pipe 13 Cover 14. Blast mechanism

Claims

1. An apparatus for peeling a coating from a coated film having a coating on at least one side of a base film, Multiple nozzles are provided in the film transport direction, positioned opposite the surface of the coated film having the coating, and spraying particles together with compressed air toward the coating. From the nozzle located upstream in the film transport direction, compressed air is used to spray particles composed of dry ice or ice. From the nozzle located downstream in the film transport direction, compressed air is used to spray non-foreign particles composed of materials contained in the base film. While removing a portion of the base film, the coating is peeled off from the coated film. A device for peeling coatings from coated films.

2. A method for peeling a coating from a coated film having a coating on at least one side of a base film, Upstream of the film transport direction, particles composed of dry ice or ice are sprayed together with compressed air toward the coating of the coated film. Downstream in the film transport direction, non-foreign particles composed of materials contained in the base film are sprayed together with compressed air toward the coating of the coated film. While removing a portion of the base film, the coating is peeled off from the coated film. A method for removing a coating from a coated film.

3. A method for producing a base film from which a coating has been removed, comprising using the method for removing a coating from a coated film according to claim 2, and removing the coating from a coated film having a coating on at least one side of the base film to obtain the base film.

Images