JP7672005B2 - METHOD FOR RECYCLING RELEASE SHEET, RECYCLABLE RELEASE SHEET, AND RESIN SHEET LAMINATE USING THE SAME - Google Patents

Description

The technology disclosed in this specification relates to a method for recycling release sheets and release sheets suitable for recycling.

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 Law for Promoting Recycling of Plastic Resources has been enacted, and the collection and recycling of resin products has been particularly attracting attention. For example, the reuse of resin substrates used in the manufacturing process of laminates including polarizing plates has been considered (see, for example, 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 (see, for example, Japanese Patent Application Laid-Open No. 2003-233664).

Patent Publication 2015-118388 Patent Publication 2017-139008

In recent years, efforts have been made not only to simply recycle resin materials, but also to horizontal recycling, in which resin materials recovered 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 recovering used materials becomes a bigger problem.

As one type of horizontal recycling, efforts are beginning to be made to collect the release sheets of labels that have an adhesive layer and are provided with release sheets after use, regenerate them into resin material, 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 achieving this have not yet been fully established.

The object of the present invention is to provide a method for recycling release sheets that can efficiently recycle the release sheets while accurately removing foreign matter, and a release sheet suitable for this method.

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 the present 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.

The recycling method disclosed in this specification and the release sheet used in this method allow the three-dimensional shape formed on the release sheet to be used for sorting inspection, making it possible to realize efficient recycling of used release sheets.

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

(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 showing 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.

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

In the recycling method of this embodiment, the release sheet 10 peeled off from the 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 side of the base sheet 7, and a release sheet 10 bonded to the adhesive layer 5.

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 an uneven 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. The first surface 6 has an uneven pattern in which the concave portions are repeatedly arranged at regular intervals in a two-dimensional direction, and the adhesive layer 5 has an inverse uneven pattern in which a plurality of convex portions 13 are partitioned by lattice-shaped grooves 11 corresponding to this uneven pattern. It can also be said that the uneven pattern formed on the first surface 6 is formed by the lattice-shaped protrusions 9.

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 sheet to the adherend without trapping air.

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 that improves 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.

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 cost. 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 distance between adjacent three-dimensional shapes 4 is about 20 μm to 1000 μm, and grooves 11 that serve as air passages can be formed in the adhesive layer 5 is preferable because it can effectively reduce air entrapment when the adhesive sheet 15 is applied.

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. The adhesive may be a plant-derived adhesive, or may contain a plant-derived tackifier or the like.

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 of its high versatility and 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.

The release agent layer 3 contains a release agent including a silicone resin, a fluororesin, or the like, and in the example shown in FIG. 1, is formed 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.

The inspection system 30 shown in FIG. 4 includes, for example, a memory 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 memory unit 23 that can store data on the release sheet 10 other than the data on the three-dimensional shape 4 as necessary. Examples of data stored in the second memory 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.

The imaging unit 25 has a light source 24 that irradiates the inspection object with visible light, infrared light, or the like, and a camera 22 that receives reflected light from the inspection object or transmitted light through the inspection object to capture the shape of the inspection object and generate image data. The camera 22 may be an ultrasonic camera that can detect ultrasonic waves, in which 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 obtained image 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 determination unit 27 compares the image data of the inspection object with the data of the three-dimensional shape 4 stored in the storage unit 21, and determines that the inspection object is not a foreign object if the image data of the inspection object includes the three-dimensional shape 4, and determines 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 determination 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 storage unit 21, the second storage unit 23, and the determination 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.

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

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

In step S3, the used release sheet 10 that has reached a predetermined amount is collected from the user in a collection container in either a roll sheet or a sheet. There are no particular limitations on the length of the roll sheet, the size of the sheet, or the presence or absence of cut portions.

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. 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.

Figures 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 Figure 1 are formed. As with release sheet 10A, a concave-convex pattern may be formed in which hemispherical or cylindrical three-dimensional shapes 4A are arranged two-dimensionally, and as with 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.

In step S5, the contents of the collection container are subjected to a sorting inspection. Details of this step are shown in Figure 6.

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 data that can determine whether or not it contains a three-dimensional shape 4. For example, a two-dimensional image may be captured by photographing the inspection surface vertically from above.

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 contains 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.

In this step, if the image of the inspection surface does not include a 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 roll sheet or sheet being inspected is not a used release sheet. This determination and shape matching is 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.

If the inspection system 30 has a second memory 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 memory unit 23, this 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 memory 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.

When 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 determined 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.

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, the judgment unit 27 judges in step S5C that the rolled sheet or single sheet being inspected is a used release sheet 10. If the object being inspected 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.

Next, in step S6 shown in FIG. 3, any foreign matter determined not to be a used release sheet 10 during the sorting inspection is removed from the contents of the collection container.

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 are no particular problems, the release agent layer 3 may not be removed to form pellets.

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% of recycled resin raw material. The release sheet 10 may contain so-called horizontally recycled resin raw material recycled from used release sheets. The use of horizontally recycled materials is preferable because it leads to direct savings in petroleum resources.

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 marker 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 identification markers, 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.

The uneven pattern with repeated three-dimensional shapes 4 can be formed by applying a known embossing process to a flat release sheet. Since such uneven patterns are generally difficult for third parties to accurately imitate, using them as identification markers makes it possible to remove foreign matter with high accuracy.

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 still be used as an identification marker. However, the inspection surface of the object to be inspected must be the surface on which the three-dimensional shape 4 is formed, and the object must be transported in a state where it can be photographed by the imaging unit 25.

In the method of this embodiment, the adhesive sheet 15 included in the resin sheet laminate 20 does not necessarily have to have a base sheet 7, and may have a configuration in which it does not have a base and is sandwiched between two release sheets 10. In addition, a 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 the release sheet 10.

The storage process (step S4), inspection process (step S5), and foreign matter removal process (step S6) shown in FIG. 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 foreign matter above the allowable limit.

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.

As shown in FIG. 8, the recycled material determination device 40 includes a 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 the measurement unit 57 and the data calculated by the calculation unit 53.

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

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

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 sheet shape using a collection container. The collection container used here is preferably a dedicated container with standardized standards for size, mass, capacity, etc., 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 a FIBC box, the used release sheet 10 can be efficiently collected using a unit container item collection and delivery service (such as JITBOX Charter Service (registered trademark)).

In step S14, the collection containers collected by the delivery system from the user businesses 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 business. 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.

In step S15, the memory unit 21 of the inspection system 30 stores the three-dimensional shape 4 of the release sheet 10. In this embodiment, the memory unit 21 also stores the uneven pattern in which the three-dimensional shape 4 is repeated. This step may be performed at any time before the subsequent sorting inspection.

In step S16, the predicted collection amount of the used release sheet 10 from the user is calculated based on the stored supply amount of the resin sheet laminate 20. The calculation of the predicted collection amount can be obtained, for example, by multiplying the mass of the supplied resin sheet laminate 20 by the mass ratio of the release sheet 10 per unit mass of the resin sheet laminate 20. The sales area (m ² ) may be stored when the resin sheet laminate 20 is sold, and the predicted collection amount may be calculated by multiplying the sales area by the mass per unit area of the release sheet 10. In order to improve accuracy, the calculation unit 53 may 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.

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

The evaluation unit 55 can determine whether the recovery amount and the predicted recovery amount match based on whether the difference between the two is within a specified range. The specified range can be set uniformly to a value of about 10% to 30%, or can be set based on the results of a statistical analysis.

If it is determined in the previous step that an inspection should 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 according to the procedure of steps S5A to S5D shown in FIG. 6, which was described in the first embodiment, to determine whether or not the contents contain foreign matter. 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.

Next, in step S19, any foreign matter determined not to be a used release sheet 10 during the sorting inspection is removed from the contents of the collection container.

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

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 contents in the collection container is calculated by the measurement unit 57, and the predicted collected amount is calculated by the calculation unit 53. The evaluation unit 55 compares the collected amount with the predicted collected amount, and if the difference exceeds a predetermined range, it determines that the collection container is to be subject to a sorting inspection.

The supply amount storage unit 51 can be configured to directly input the supply amount of the resin sheet laminate 20, or can 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, or can be configured to measure the mass of the collection container by an independent device. The evaluation unit 55 may have a function to output 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 perform the function of calculating the collection amount from the mass of the collection container.

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 for each collection container to the second base can be made. In addition, based on this schedule, arrangements can be made with a delivery company for transfer. In this way, transfer between bases can be made smoothly, and the securing of collection sites 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.

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

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 collected 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 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 recycling costs using a system that stores various parameters that affect the recycling costs, such as the transportation costs of the release sheet 10 and the price of the chemicals used for recycling. In this way, the user can be more convinced and their 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 costs from the transaction price of the resin raw material.

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 the efficiency of 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 inspected, foreign matter can be detected and removed accurately and efficiently using a method that uses the three-dimensional shape 4 of the release sheet 10 as an identification marker.

The release sheet recycling method disclosed herein is useful in the field of environmentally friendly adhesive sheets, such as labels.

Reference Signs List 1: Substrate 3: Release agent layer 4, 4A, 4B: Three-dimensional shape 5: Adhesive layer 7: Substrate sheet 9: Protrusion 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 section 27: Determination section 30: Inspection system

Claims (10)

supplying a resin sheet laminate to a user, the resin sheet laminate including: a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer; and a release sheet laminate bonded to the pressure-sensitive adhesive sheet, the release sheet having a first surface on which a release agent layer is formed and a second surface opposed to the first surface, the release sheet having a substrate made of a resin material with a three-dimensional shape formed on at least one of the first surface and the second surface;
A step of collecting the used release sheet peeled off from the resin sheet laminate from the user using a collection container in the form of either a roll sheet or a sheet ;
A step of separately inspecting the contents of the collection container collected from the user ;
removing foreign matter determined not to be the used release sheet by the sorting inspection from the contents of the collection container;
and a step of regenerating the used release sheet into a resin raw material,
The step of sorting and inspecting the contents of the collection container includes:
An inspection system having a storage unit, an imaging unit, and a judgment unit, the imaging unit imaging an inspection surface of the content;
a step in which the determination unit compares the photographed image of the inspection surface with the three-dimensional shape of the release sheet previously stored in the storage unit;
A method for recycling release sheets, comprising a step of determining that a roll sheet or a single sheet among the contents, the shape of the inspection surface of which does not include the three-dimensional shape stored in the memory unit, is not a used release sheet. The recycling method according to claim 1 , further comprising a step of storing the three-dimensional shape of the release sheet in the storage unit before the step of sorting and inspecting the contents of the collection container. supplying a resin sheet laminate to a user, the resin sheet laminate including: a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer; and a release sheet having a substrate made of a resin material, the substrate having a first surface on which a release agent layer is formed and a second surface opposed to the first surface, the release sheet having a three-dimensional shape formed on at least one of the first surface and the second surface;
A step of collecting the used release sheet peeled off from the resin sheet laminate from the user using a collection container in the form of either a roll sheet or a sheet ;
A step of separately inspecting the contents of the collection container collected from the user ;
removing foreign matter determined not to be the used release sheet by the sorting inspection from the contents of the collection container;
and a step of regenerating the used release sheet into a resin raw material,
The concave-convex pattern is a pattern in which the three-dimensional shape is repeatedly arranged in a two-dimensional direction,
The step of sorting and inspecting the contents of the collection container includes:
An inspection system having a storage unit, an imaging unit, and a judgment unit, the imaging unit imaging an inspection surface of the content;
a step in which the determination unit compares the photographed image of the inspection surface with the concave-convex pattern of the release sheet stored in advance in the storage unit;
A method for recycling release sheets, comprising: determining that among the contents, roll sheets or individual sheets whose inspection surface shape does not include the uneven pattern stored in the memory unit are not used release sheets. The recycling method according to claim 3 , further comprising a step of storing the three-dimensional shape and the concave-convex pattern of the release sheet in the storage unit before the step of sorting and inspecting the contents of the collection container. the pressure-sensitive adhesive sheet further includes a base sheet provided on a surface of the pressure-sensitive adhesive layer opposite to the release sheet,
The recycling method according to claim 1 , wherein the three-dimensional shape is formed on at least the first surface of the release sheet. The recycling method according to claim 1 , wherein in the step of the photographing unit photographing the inspection surface of the content, photographing of the inspection surface is performed continuously. The method further includes a step of storing a configuration of the release sheet in a second storage unit of the analysis system before the step of classifying and inspecting the contents of the collection container;
The step of sorting and inspecting the contents of the collection container includes:
analyzing the composition of the contents on a roll or sheet by sheet basis using visible light, infrared light, or ultrasonic waves with the analysis system;
A step of comparing the analyzed configuration of the contents with the configuration of the release sheet stored in the second storage unit;
The recycling method according to any one of claims 1 to 4, further comprising a step of determining that a roll sheet or a single sheet among the contents, the analyzed composition of which is different from the composition of the stored release sheet, is not the used release sheet. The recycling method according to any one of claims 1 to 4 , wherein the base material of the release sheet is made of a polyester resin. The recycling method according to any one of claims 1 to 4 , wherein the base material of the release sheet contains 10% by mass or more of recycled resin raw material. storing the amount of the resin sheet laminate supplied to the user in a supply amount storage unit;
measuring the mass of the collection container collected from the user and calculating the amount of the used release sheets in the collection container as a collection amount;
calculating, in a calculation unit, a predicted amount of the used release sheet to be collected from the user based on the supply amount stored in the supply amount storage unit;
The method further includes a step of comparing the collected amount with the predicted collected amount in an evaluation unit, and determining that the contents of the collection container are to be subjected to a separate inspection if a difference between the collected amount and the predicted collected amount exceeds a predetermined range,
The recycling method according to any one of claims 1 to 4, wherein in the step of carrying out a separation inspection of the contents of the collection container, an inspection is carried out on the contents of the collection container determined to be subject to the separation inspection using the collection amount and the predicted collection amount .

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