Release sheet for recycling, and resin sheet laminate using the same

Abstract

To provide a release sheet recycling method that enables efficient and precise foreign matter removal, and a release sheet suitable for the method.SOLUTION: A release sheet recycling method involves: step S1 for supplying a resin sheet laminate including an adhesive sheet and a release sheet having a substrate composed of a resin material that is formed into a three-dimensional shape, to a business end-user; step S3 of recovering used release sheets by means of a recovery container; and step S5 for sorting and inspecting the contents of the recovery container. In step S5, the sorting and inspection of the contents are performed by using the three-dimensional shape as an identification marker.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a method for recycling a release sheet and a release sheet suitable for recycling. [Background technology]

[0002] In recent years, with the rise in environmental awareness, it has been proposed to reuse and recycle various products, from industrial products to everyday items. The Plastic Resource Recycling Promotion Law has been enacted, and the collection and recycling of resin products has been attracting particular attention. For example, the reuse of resin substrates used in the manufacturing process of laminates including polarizing plates has been considered (for example, see Patent Document 1). In recycling, it is important to efficiently collect and separate materials. The creation of a recycling system for printing materials is also being considered (for example, see Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2015-118388 [Patent Document 2] Patent Publication 2017-139008 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, efforts have been made not only to simply recycle resin materials, but also to horizontal recycling, in which resin materials collected from used products are regenerated and used as materials for the same products. In the case of horizontal recycling, the regenerated resin materials must maintain a quality close to that of virgin materials, so the contamination of foreign matter when collecting used materials becomes a bigger problem.

[0005] As one type of horizontal recycling, attempts are beginning to be made to collect the release sheets of labels that have an adhesive layer and a release sheet after use, regenerate them into resin materials, and use them again to manufacture release sheets. Labels come in a variety of types and materials, but one type of release sheet can be used for many labels, so by collecting the release sheets, they can be recycled effectively. However, because horizontal recycling of release sheets is a new initiative, the methods for realizing this have not yet been fully established.

[0006] An object of the present invention is to provide a method for recycling a release sheet that can efficiently recycle the release sheet while removing foreign matter with high accuracy, and a release sheet suitable for this method. [Means for solving the problem]

[0007] The method for recycling a release sheet disclosed in the present specification includes the steps of: supplying a resin sheet laminate to a user, the resin sheet laminate including: an adhesive sheet having an adhesive layer; and a release sheet laminated to the adhesive sheet, the release sheet having a first side on which a release agent layer is formed and a second side opposite to the first side, the release sheet having a base material made of a resin material with a three-dimensional shape formed on at least one of the first side and the second side; collecting from the user the used release sheet peeled off from the resin sheet laminate in a shape selected from a roll sheet and a sheet-like sheet using a collection container; storing the three-dimensional shape of the release sheet in a memory unit of an inspection system having a memory unit, an imaging unit, and a judgment unit; The step of separately inspecting the contents of the collection container includes a step in which the photographing unit photographs the inspection surface of the contents, a step in which the judgment unit compares the photographed image of the inspection surface with the three-dimensional shape stored in the memory unit, and a step in which the roll sheet or single sheet of the contents, the shape of the inspection surface of which does not include the three-dimensional shape stored in the memory unit, is judged to be not a used peel-off sheet. In this recycling method, if a concave-convex pattern in which the three-dimensional shape is repeatedly arranged in a two-dimensional direction is stored in advance in the memory unit, the photographed image of the inspection surface can be compared with the concave-convex pattern stored in the memory unit. The release sheet for recycling disclosed in the present specification can be regenerated by using the above-mentioned recycling method. This release sheet for recycling includes a substrate having a three-dimensional shape formed on at least one of a first surface and a second surface, the substrate being made of a resin material, and a release agent layer provided on the surface of the substrate on which the three-dimensional shape is formed. The resin sheet laminate disclosed in this specification is regenerated by the above-mentioned recycling method, and comprises a release sheet having a first surface and a second surface opposite to the first surface, and an adhesive sheet having an adhesive layer bonded to the first surface of the release sheet. Effect of the Invention

[0008] According to the recycling method disclosed in this specification and the release sheet used in this method, the three-dimensional shape formed on the release sheet can be used for sorting inspection, thereby enabling efficient recycling of used release sheets. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing a resin sheet laminate provided with a release sheet applied to a method for recycling a release sheet according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a plan view of the release sheet as viewed from the side in contact with the pressure-sensitive adhesive layer. [Diagram 3]FIG. 3 is a flow diagram showing the method for recycling the release sheet according to the first embodiment. [Figure 4] FIG. 4 is a block diagram showing an inspection system used in the recycling method according to the first embodiment. [Diagram 5] 5(a) and (b) are plan views showing release sheets 10A and 10B on which three-dimensional shapes 4A and 4B are formed, respectively. [Figure 6] FIG. 6 is a flow chart showing details of the steps for carrying out the content sorting inspection. [Figure 7] FIG. 7 is a flow chart showing a method for recycling a release sheet according to a second embodiment of the present disclosure. [Figure 8] FIG. 8 is a block diagram showing a recycled material determination device used in the method of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (First embodiment) Fig. 1 is a cross-sectional view showing a resin sheet laminate provided with a release sheet, and Fig. 2 is a plan view of the release sheet as viewed from the side in contact with the pressure-sensitive adhesive layer. This release sheet 10 is applied to the recycling method according to the first embodiment.

[0011] FIG. 3 is a flow chart showing the release sheet recycling method according to the first embodiment, and FIG. 4 is a block diagram showing an inspection system used in the recycling method of this embodiment.

[0012] In the recycling method of the present embodiment, a release sheet 10 peeled off from a resin sheet laminate 20 shown in Fig. 1 is collected. The resin sheet laminate 20 includes a base sheet 7, an adhesive sheet 15 having an adhesive layer 5 provided on one surface of the base sheet 7, and a release sheet 10 bonded to the adhesive layer 5.

[0013] The release sheet 10 has a first surface 6 on which a release agent layer 3 is formed, and a second surface 8 facing the first surface 6, and a substrate 1 made of a resin material on which a three-dimensional shape 4 is formed on at least one of the first surface 6 and the second surface 8. Here, the "three-dimensional shape" means a three-dimensional shape with respect to a plane, such as a concave portion, a convex portion, or a concave-convex portion, and the shape is not particularly limited as long as it is three-dimensional. The substrate 1 is in a sheet form, and in Figs. 1 and 2, an example is shown in which the three-dimensional shape 4 is a concave portion that is concave in a frustum shape. On the first surface 6, a concave-convex pattern is formed in which concave portions are repeatedly arranged at regular intervals in a two-dimensional direction, and on the pressure-sensitive adhesive layer 5, a reverse concave-convex pattern is formed in which a plurality of convex portions 13 are partitioned by lattice-shaped grooves 11 corresponding to this concave-convex pattern. It can also be said that the concave-convex pattern formed on the first surface 6 is formed by a lattice-shaped protrusion portion 9.

[0014] With this configuration, air escapes from the grooves 11 when the adhesive sheet 15 is attached to the adherend, making it possible to attach the adhesive sheet to the adherend without trapping air.

[0015] The base sheet 7 may be formed of one or more materials selected from a resin sheet, paper, and synthetic paper, or may be a laminate of these materials. When the adhesive sheet 15 is a label or the like, an easy-adhesion layer for improving adhesion to ink may be formed on at least one of the surface of the base sheet 7 that contacts the adhesive layer 5 and the surface opposite to this surface.

[0016] The size of the three-dimensional shape 4 is not particularly limited as long as it can be identified by a camera or the like, but for example, a height of 1 μm or more and a length and width of 2 μm or more is preferable because the equipment required for imaging can be kept relatively low. The size of the uneven pattern is also not particularly limited, but a pattern in which the height of the three-dimensional shape 4 is, for example, 5 μm to 100 μm, the length and width of the three-dimensional shape 4 is, for example, 20 μm to 1000 μm, the interval between adjacent three-dimensional shapes 4 is about 20 μm to 1000 μm, and the adhesive layer 5 can form grooves 11 that serve as air passages, is preferable because air entrapment can be effectively reduced when the adhesive sheet 15 is attached.

[0017] The adhesive layer 5 may be formed using one or more adhesives selected from urethane-based, acrylic-based, silicone-based, polyester-based, and rubber-based adhesives. As the adhesive, a plant-derived adhesive may be used, or a plant-derived tackifier or the like may be added.

[0018] The substrate 1 of the release sheet 10 may be made of a recyclable resin material. The resin material is not particularly limited, but polyester resin, especially polyethylene terephthalate (PET), is preferably used because it is highly versatile and has established recycling technology. The substrate 1 may be transparent or white, but does not need to be colored with ink or the like from the viewpoint of reuse. When the substrate 1 is made of a porous resin material, it is white. Since the substrate 1 is porous, the amount of resin material used can be reduced compared to when a typical transparent resin film is used. For example, Kamishine (registered trademark) by Toyobo Co., Ltd. can be used as the substrate 1. From the viewpoint of environmental consideration, the substrate 1 may contain biomass polyester containing a plant-derived material.

[0019] The release agent layer 3 contains a release agent containing a silicone resin, a fluororesin, or the like, and in the example shown in Fig. 1, is formed so as to follow the shape of the three-dimensional shape 4. The thickness of the release agent layer 3 is generally about 5 µm or less. An antistatic layer may be provided on the second surface 8 and / or the first surface 6 of the substrate 1.

[0020] 4 includes, for example, a storage unit 21 capable of storing data on the three-dimensional shape 4 of the release sheet 10, an imaging unit 25 that images the inspection surface of the object to be inspected in the form of a rolled sheet or a single sheet, and a judgment unit 27. The inspection system 30 may further include a second storage unit 23 capable of storing data on the release sheet 10 other than the data on the three-dimensional shape 4, as necessary. Examples of the data held in the second storage unit 23 include data on the configuration of the release sheet 10, such as the constituent materials and thicknesses of the substrate 1 and the release agent layer 3.

[0021] The imaging unit 25 has a light source 24 that irradiates the object to be inspected with visible light, infrared light, or the like, and a camera 22 that receives reflected light from the object to be inspected or transmitted light through the object to capture an image of the object to be inspected and generate image data. The camera 22 may be an ultrasonic camera that can detect ultrasonic waves, and in that case, an ultrasonic oscillator is provided in addition to or instead of the light source 24. The imaging method of the imaging unit 25 is not particularly limited, but it is preferable that the resolution of the image obtained is high. For example, even if the height of the three-dimensional shape 4 shown in Figures 1 and 2 is 20 μm to 100 μm and the length and width are about 50 μm to 500 μm, it is preferable that an image with a resolution that allows the shape to be identified is obtained. The judgment unit 27 compares the image data of the inspection object with the data of the three-dimensional shape 4 stored in the memory unit 21, and judges that the inspection object is not a foreign object if the image data of the inspection object includes the three-dimensional shape 4, and judges that the inspection object is a foreign object if the image data of the inspection object does not include the three-dimensional shape 4. The judgment of whether or not the inspection object is a foreign object is performed for each roll sheet and each sheet. At least one of the memory unit 21, the second memory unit 23, and the judgment unit 27 may be provided as a separate device outside the inspection device having the imaging unit 25, for example. The inspection device may be a handheld type or a stationary type whose position is fixed. When a stationary inspection device is used, it is preferable to continuously inspect the inspection object transported by a transport device such as a belt conveyor. Although not shown, the inspection system 30 may include a known analysis device that uses reflected or transmitted visible or infrared light, ultrasonic waves, etc. For example, an infrared analysis device that can analyze the configuration of the release sheet 10 can be used for the classification inspection described below.

[0022] The release sheet 10 is recycled according to the procedure shown in Figure 3. First, in step S1, the resin sheet laminate 20 is supplied / sold to a user, or sold to a processor, who processes it and then supplies it to the user. The processor prints on the surface of the adhesive sheet 15 and performs processing such as punching and half-cutting. In some cases, the user may perform processing such as printing themselves.

[0023] Next, in step S2, the user who has been supplied with the resin sheet laminate 20 or a processed product thereof uses it by peeling off the adhesive sheet 15 from the release sheet 10. The user stores and accumulates the used release sheet 10 after peeling, rather than discarding it.

[0024] In step S3, the used release sheet 10 that has reached a predetermined amount is collected from the user in a collection container in the form of either a roll sheet or a single sheet. The length of the roll sheet, the size of the single sheet, and the presence or absence of cut portions are not particularly limited.

[0025] In step S4, the storage unit 21 stores the three-dimensional shape 4 of the release sheet 10. In this embodiment, the storage unit 21 also stores the uneven pattern in which the three-dimensional shape 4 is repeated. Here, "storing the three-dimensional shape 4 and the uneven pattern" means storing data such as an image that can identify the three-dimensional shape 4 and the uneven pattern. The image data that can identify the three-dimensional shape 4 and the uneven pattern may include data of a two-dimensional image taken from a specific direction, or may include three-dimensional image data reconstructed from multiple two-dimensional image data. This step may be performed at any time before the subsequent sorting inspection.

[0026] 5(a) and (b) are plan views showing release sheets 10A and 10B on which three-dimensional shapes 4A and 4B different from those of the release sheet 10 shown in FIG. 1 are formed. As in the release sheet 10A, a concave-convex pattern in which hemispherical or cylindrical three-dimensional shapes 4A are arranged two-dimensionally may be formed, or as in the release sheet 10B, the three-dimensional shapes 4B may be letters engraved in a concave shape. In this way, release sheets on which various three-dimensional shapes are formed can be applied to the recycling method of this embodiment.

[0027] In step S5, the contents of the collection container are subjected to a classification inspection. The details of this step are shown in FIG.

[0028] First, in step S5A, the imaging unit 25 sequentially captures the inspection surface of the contents of the collection container for each roll sheet or each individual sheet. The image data of the inspection surface generated by the imaging unit 25 is sent to the determination unit 27. This image data may be a two-dimensional image or a three-dimensional image as long as it is possible to determine whether or not the image data includes a three-dimensional shape 4. For example, a two-dimensional image of the inspection surface captured vertically from above may be captured.

[0029] Next, in steps S5B and S5C, the judgment unit 27 compares the image of the inspection surface with the three-dimensional shape 4 of the release sheet 10 read from the memory unit 21. In this step, it is checked whether the image of the inspection surface includes a shape that matches the three-dimensional shape 4. If a concave-convex pattern is stored in the memory unit 21, the image of the inspection surface is compared with the concave-convex pattern read from the memory unit 21.

[0030] In this step, if the image of the inspection surface does not include the three-dimensional shape 4, or if the image of the inspection surface does not include a pattern that matches the uneven pattern, in step S5D, it is determined that the inspected roll sheet or sheet is not a used release sheet. This determination and shape matching are performed by the determination unit 27, but if the image of the inspection surface is clear, the matching or determination can also be done visually.

[0031] If the inspection system 30 has a second storage unit 23 and an analysis device that uses visible light, infrared light, or ultrasonic waves, and the configuration data of the release sheet 10 is stored in the second storage unit 23, the step may further include analyzing the configuration of the contents and comparing the analyzed configuration of the contents with the configuration of the release sheet 10 read from the second storage unit 23. If the analyzed configuration matches the stored configuration of the release sheet 10, the judgment unit 27 judges that the roll sheet or sheet to be inspected may be considered as a used release sheet 10, and if the two configurations are different from each other, it judges that the roll sheet or sheet to be inspected is not a used release sheet 10. In this analysis device, the thickness and material of each layer are analyzed. In some cases, the resin sheet laminate 20 has a configuration in which multiple release sheets 10 are connected by a connection tape. According to the method of judging whether or not a foreign object is present based on the configuration of the release sheet 10, a connection tape made of a different material from the release sheet 10 can be efficiently identified.

[0032] If a flat release sheet and a release sheet 10 having a three-dimensional shape 4 formed thereon, both made of the same material, are mixed in the collection container, the flat release sheet is determined to be a foreign object in step S5D. In this case, if an analysis of the configuration is performed and it is found that the flat release sheet and the release sheet 10 are made of the same material, it can be determined that this release sheet can be sent to the subsequent recycling step together with the release sheet 10. For this reason, it is preferable to perform a step of comparing the analysis results by the inspection system 30 with the configuration of the release sheet 10 after step S5D.

[0033] On the other hand, if the image of the inspection surface contains a three-dimensional shape 4, or if the image of the inspection surface contains a pattern that matches the uneven pattern, in step S5C, the judgment unit 27 judges that the rolled sheet or single sheet to be inspected is a used release sheet 10. When the inspection object is a rolled sheet, it is sufficient to inspect only a portion of it, and it is not necessary to photograph the inspection surface of the entire sheet.

[0034] Next, in step S6 shown in FIG. 3, foreign matter that is determined not to be a used release sheet 10 in the separation inspection is removed from the contents of the collection container.

[0035] In step S7, the contents may be pretreated as necessary. For example, the used release sheet 10 may be washed with water and alkaline water to remove the release agent layer 3 and the antistatic layer, and then cut into an appropriate size and heated and melted to form pellets. If there is no particular problem, the release agent layer 3 may not be removed to form pellets.

[0036] In step S8, the used release sheet 10 is recycled into a resin raw material. The method of recycling into a resin raw material is not particularly limited, and various methods can be used according to the resin composition of the release sheet 10. The recycled resin raw material can be used again to produce a release sheet. When producing a release sheet, only the recycled raw material can be used, or it can be mixed with unused raw materials. Considering the burden on the environment, it is preferable that the base material of a newly produced release sheet contains at least 10 mass% or more of recycled resin raw material. The release sheet 10 may contain so-called horizontally recycled resin raw material recycled from a used release sheet. The use of horizontally recycled materials is preferable because it leads to direct savings in petroleum resources.

[0037] According to the release sheet recycling method of this embodiment, the three-dimensional shape 4 formed on the release sheet 10 is used as an identification mark to indicate whether or not it is a foreign object. When characters or marks printed on the surface of the release sheet are used as an identification mark, it may be necessary to remove the ink when recycling the resin raw material. According to the method of this embodiment, the resin raw material can be recycled without adding a process such as removing the ink. In addition, since the identification of the three-dimensional shape 4 can be performed in a short time compared to the analysis of the constituent materials, it is possible to perform continuous sorting inspections.

[0038] The uneven pattern with the repeated three-dimensional shape 4 can be formed by applying a known embossing process to a flat release sheet. Since such uneven patterns are generally difficult for a third party to accurately imitate, using this as an identification marker makes it possible to remove foreign matter with high accuracy.

[0039] According to the method of this embodiment, even if the three-dimensional shape 4 is formed on the back surface (second surface 8) of the release sheet 10, rather than on the release surface side of the release sheet 10, it can be used as an identification marker. However, the inspection surface of the inspection object must be the surface on which the three-dimensional shape 4 is formed, and it must be transported in a state where it can be photographed by the imaging unit 25.

[0040] In the method of the present embodiment, the adhesive sheet 15 included in the resin sheet laminate 20 does not necessarily have to have the base sheet 7, and may have a configuration in which the adhesive sheet 15 does not have a base and is sandwiched between two release sheets 10. Also, the resin sheet laminate 20 in which the release agent layer 3 is provided on both sides of the base 1 and the release sheet 10 is provided only on one side of the so-called substrate-less type adhesive sheet 15 may be sold in step S1. In this case, the resin sheet laminate 20 may be provided in a roll state in which the back surface (second surface) of the release sheet 10 is wound so as to contact the surface of the adhesive layer 5 opposite to the release sheet 10.

[0041] 4 may be performed consecutively after receiving the release sheet collected from the user in step S3. Alternatively, steps S4 and S5 may be performed as an acceptance inspection of the release sheet collected from the user. In that case, it is possible to refuse to accept the release sheet when it is found that the release sheet contains more foreign matter than the allowable limit.

[0042] Second Embodiment A method for recycling a release sheet according to a second embodiment of the present disclosure will now be described. Fig. 7 is a flow chart showing the method for recycling a release sheet according to the second embodiment, and Fig. 8 is a block diagram showing a recycled material determination device used in the method of this embodiment.

[0043] As shown in FIG. 8, recycled material determination device 40 includes supply amount memory unit 51 that stores data on the amount of supply to businesses using adhesive sheets, a measurement unit 57 that measures the mass of the object to be inspected, a calculation unit 53, and an evaluation unit 55 that makes a predetermined judgment based on the measurement data from measurement unit 57 and the data calculated by calculation unit 53.

[0044] The resin sheet laminate 20 shown in Fig. 1 is supplied to a user in step S11 shown in Fig. 7. The resin sheet laminate 20 may be supplied to the user after being subjected to processing such as printing on the surface of the base sheet 7 or punching by a processing company. Here, data such as the supply amount of the resin sheet laminate 20 or its processed product to the final user is stored in the supply amount storage unit 51 for each user.

[0045] In step S12, the user company peels off the adhesive sheet 15 from the release sheet 10 and uses it. The user company stores and accumulates the used release sheet 10 after peeling, rather than discarding it.

[0046] In step S13, the used release sheet 10 that has reached a predetermined amount is collected from the user in either a roll sheet or a single sheet form using a collection container. The collection container used here is preferably a dedicated container with standardized standards for size, mass, capacity, etc., in order to facilitate measurement in subsequent processes. The dedicated container may be assigned a container number and linked to the container mass. A specific example of a dedicated container is a FIBC box that combines a flexible container bag (FIBC bag) with a metal frame. By using the FIBC box, the used release sheet 10 can be efficiently collected using a unit container item collection and delivery transport service (such as JITBOX Charter Service (registered trademark)).

[0047] In step S14, the collection containers collected from the user companies by the delivery system are accumulated at a specified base. The accumulated collection containers are weighed, and the amount of waste in the collection container is stored and tallied for each user company. If the mass of the collection container itself is known, or if a dedicated container is used as the collection container, the amount of waste collected can be calculated by the difference between the mass of the collection container including the contents and the mass of the empty collection container.

[0048] In step S15, the storage unit 21 of the inspection system 30 stores the three-dimensional shape 4 of the release sheet 10. In this embodiment, the storage unit 21 also stores a concave-convex pattern in which the three-dimensional shape 4 is repeated. This step may be performed at any time before the subsequent separation inspection.

[0049] In step S16, a predicted recovery amount of used release sheets 10 from users is calculated based on the stored supply amount of resin sheet laminates 20. The predicted recovery amount can be calculated, for example, by multiplying the mass ratio of release sheets 10 per unit mass of resin sheet laminate 20 by the mass of the supplied resin sheet laminate 20. 2) and calculate the predicted collection amount by multiplying the sales area by the mass per unit area of ​​the release sheet 10. To improve accuracy, the calculation unit 53 can calculate the predicted collection amount by taking into account past collection amount results and the like as various parameters. The calculation of the predicted collection amount can be performed at any time from when the supply amount of the resin sheet laminate 20 is determined to when it is compared with the collection amount.

[0050] In step S17, the collection amount for each user is compared with the predicted collection amount to determine whether the corresponding collection container is subject to inspection. If the used release sheet 10 is collected correctly from the user, the collection amount should be approximately equal to the predicted collection amount. If the collection amount is significantly lower than the predicted collection amount, it is suspected that the user does not collect enough used release sheets 10 or that something other than the used release sheet 10 has been placed in the collection container. If the collection amount is significantly higher than the predicted collection amount, it is suspected that something other than the used release sheet 10 has been placed in the collection container. If there is a large discrepancy between the collection amount and the predicted collection amount, it is highly likely that the used release sheet 10 has not been collected correctly, and therefore the contents of the corresponding collection container are inspected. On the other hand, if the collection amount is equal to the predicted collection amount, it is possible to not inspect the contents of the corresponding collection container or to only perform a simple inspection.

[0051] In the evaluation unit 55, whether the recovery amount and the predicted recovery amount match can be determined based on whether the difference between them is within a predetermined range. The predetermined range can be set to a uniform value of about 10% to 30%, or can be set based on the results of a statistical analysis.

[0052] If it is determined in the previous step that an inspection is to be performed, then in step S18, a separation inspection of the contents of the collection container is performed. In this step, the inspection is performed in the order of steps S5A to S5D shown in FIG. 6, which were described in the first embodiment, to determine whether or not a foreign object has been mixed into the contents. In this step, in addition to the inspection using the three-dimensional shape 4, physical characteristics such as the thickness and physical properties of the object to be inspected may be inspected, optical characteristics such as total light transmittance and haze may be inspected, or a visual inspection may be performed.

[0053] Next, in step S19, any foreign matter that is determined not to be a used release sheet 10 in the separation inspection is removed from the contents of the collection container.

[0054] In step S20, the contents may be pretreated as necessary. Next, in step S21, the used release sheet 10 is recycled into a resin raw material.

[0055] In the method of this embodiment, whether the collected amount and the predicted collected amount match can be determined automatically by the recycled material determination device 40 shown in Fig. 8. The amount of content in a collection container is calculated by a measuring unit 57, and the predicted collected amount is calculated by a calculation unit 53. An evaluation unit 55 compares the collected amount with the predicted collected amount, and if the difference exceeds a predetermined range, determines that the collection container is to be subjected to a sorting inspection.

[0056] The supply amount storage unit 51 can be configured to directly input the supply amount of the resin sheet laminate 20, but can also be configured to read out business information on a server. The measurement unit 57 can be configured to be integrated with a measurement unit that measures the mass of the collection container to automatically obtain the mass of the collection container and calculate the collection amount, but can also be configured to measure the mass of the collection container by an independent device. The evaluation unit 55 may have a function of outputting a label or the like to be affixed to the corresponding collection container based on the evaluation result. The calculation unit 53 that calculates the predicted collection amount value can be configured to double as the evaluation unit 55. Also, the evaluation unit 55 can be configured to have a function of calculating the collection amount from the mass of the collection container.

[0057] In the method of this embodiment, the data on the collected amount can be used for other purposes. For example, when the collection containers collected from the user are accumulated at a first base, then transferred to a larger collection container and moved to a second base where recycling is performed, the data on the collected amount can be used to manage the inventory of the used release sheets 10 accumulated at the first base. In this case, based on the data on the supply amount of the resin sheet laminate 20 to the user, a prediction can be made as to when the accumulated amount of the used release sheets 10 at the first base will exceed a predetermined value, and a transfer schedule to the second base for each collection container can be made. In addition, based on this schedule, arrangements for transfer can be made with a delivery company. In this way, transfer between bases can be made smoothly, and the securing of a collection site can be minimized, so that recycling can be performed efficiently. When there are multiple first bases, by centrally managing the data of each first base, a plan for transfer and operation of the recycling equipment can be made more efficiently.

[0058] At the first base, the used release sheet 10 may be pre-treated in step S20 so that recycling at the second base can be performed smoothly. The pre-treated processed products may be transported to the second base. In this case, the inventory of the processed products of the used release sheet 10 may also be managed, and the transport schedule of the processed products of the used release sheet 10, which is planned based on the predicted accumulated amount of the used release sheet 10, may be modified according to the inventory of the processed products.

[0059] The data on the collected amount can also be used when calculating the price to be paid to the user. By paying the price to the user, collection can be carried out more smoothly. In addition, by paying a higher price to the user who can collect the used release sheet 10 in a state where it can be easily recycled, the awareness of the user can be raised and the used release sheet 10 in a better condition can be collected. For example, the price to be paid to the user can be set to reflect the difference in recycling costs that arise when there is little foreign matter mixed in and when there is more foreign matter than a specified value. In this case, it is preferable to comprehensively calculate the cost required for recycling using a system that stores various parameters that affect the cost required for recycling, such as the transportation cost of the release sheet 10 and the price of the chemicals used for recycling. In this way, the user can be more convinced and his / her awareness can be improved. It is also possible to calculate the price to be paid to the user by storing information on the transaction price of the recycled resin raw material in advance in the supply amount storage unit 51, etc., and subtracting the above-mentioned recycling cost from the transaction price of the resin raw material.

[0060] According to the recycling method of this embodiment, whether or not a collection container is to be inspected is easily determined based on a comparison between the collection amount and the predicted collection amount, so that the efficiency of the sorting inspection can be improved compared to the method of the first embodiment. On the other hand, for the contents of a collection container determined to be an inspection target, foreign matter can be detected and removed with high accuracy and efficiency by a method using the three-dimensional shape 4 of the release sheet 10 as an identification marker. [Industrial Applicability]

[0061] The method for recycling release sheets according to the present disclosure is useful in the field of environmentally friendly pressure-sensitive adhesive sheets, such as labels. [Explanation of symbols]

[0062] 1 Base material 3 Release agent layer 4, 4A, 4B 3D shape 5 Adhesive layer 7 Base sheet 9 Projection part 10, 10A, 10B Release sheet 11 Groove 13 Recess 15 Adhesive sheet 20 Resin sheet laminate 21 Memory section 22 Camera 23 Second memory section 24 Light source 25 Imaging unit 27 Judgment Department 30 Inspection System

Claims

1. A release sheet having a first surface and a second surface opposite to the first surface, A substrate having a three-dimensional shape formed on at least one side of the first surface and the second surface, the substrate including a resin material reproduced by horizontal recycling; a release agent layer provided on the surface of the substrate on which the three-dimensional shape is formed; A recyclable release sheet.

2. The release sheet for recycling according to claim 1 , wherein at least one of the first surface and the second surface has a concave-convex pattern formed thereon in which the three-dimensional shapes are repeatedly arranged in a two-dimensional direction.

3. The recycled release sheet according to claim 1 , wherein the substrate contains 10% by mass or more of recycled resin material.

4. 2. The recyclable release sheet according to claim 1, wherein the substrate is made of a porous material constituted by a polyester resin.

5. The recycled release sheet of claim 1 , wherein the three-dimensional shape comprises imprinted letters.

6. A release sheet for recycling according to any one of claims 1 to 5, which has a first surface and a second surface opposite to the first surface; a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer attached to the first surface of the release sheet; A resin sheet laminate comprising:

Images