Double-sided adhesive sheet

Abstract

The present invention divides and separately uses an adhesive provided to one double-sided adhesive sheet. This double-sided adhesive sheet (1) comprises an adhesive layer comprising: a first separator (10) having a first region (11) and a second region (12); a second separator (30) having third regions (31) and a fourth region (32) facing the second region; a first portion (21) provided between the first region and the fourth region; and second portions (22) provided between the second region and the third regions. The first region is more difficult to peel off from the adhesive layer than the fourth region, and the third regions are more difficult to peel off from the adhesive layer than the second region.

Description

double-sided adhesive sheet

[0001] The present disclosure relates to a double-sided pressure-sensitive adhesive sheet having a separator and a pressure-sensitive adhesive.

[0002] Conventionally, there exist double-sided pressure-sensitive adhesive sheets having pressure-sensitive adhesive layers on both sides and a separator that protects the pressure-sensitive adhesive layer before use. For example, Patent Document 1 discloses an optical pressure-sensitive adhesive sheet with a separator that is used to bond elements included in a laminate structure of an optical component.

[0003] Japanese Patent Application Publication No. 2022-58223

[0004] In conventional double-sided PSA sheets, the PSA placed between separators has been used as a single sheet, and there have been no PSA sheets that allow the PSA placed on a single sheet to be used separately. For example, in the sheet described in Patent Document 1, when one separator is peeled off, all of the PSA remains adhered to the other separator.

[0005] An object of one aspect of the present disclosure is to provide a double-sided PSA sheet in which the PSA disposed between separators can be divided and used.

[0006] In order to solve the above-mentioned problems, the double-sided pressure-sensitive adhesive sheet according to the present disclosure is a double-sided pressure-sensitive adhesive sheet formed by laminating a first separator, a pressure-sensitive adhesive layer having a pressure-sensitive adhesive, and a second separator in this order, wherein the first separator has, on its surface facing the pressure-sensitive adhesive layer, a first region that is a part of the surface, and a second region that is a region other than the first region, the second separator has, on its surface facing the pressure-sensitive adhesive layer, a third region that is at least a part of the region facing the second region, and a fourth region that is a region other than the third region, the pressure-sensitive adhesive layer has a first portion provided between the first region and the fourth region, and a second portion provided between the second region and the third region, and the first region is more difficult to peel from the pressure-sensitive adhesive layer than the fourth region, and the third region is more difficult to peel from the pressure-sensitive adhesive layer than the second region.

[0007] According to the above configuration, the adhesive provided on one double-sided adhesive sheet can be divided and used separately.

[0008] 1 is a schematic diagram showing the configuration of a double-sided pressure-sensitive adhesive sheet according to Embodiment 1 of the present disclosure. FIG. 1 is a diagram showing a state in which a first separator, a pressure-sensitive adhesive layer, and a second separator are laminated in the double-sided pressure-sensitive adhesive sheet. FIG. 2 is a diagram showing a state in which the second separator has been peeled off from the first separator in the double-sided pressure-sensitive adhesive sheet. FIG. 3 is a top view of the double-sided pressure-sensitive adhesive sheet observed from the lamination direction. FIG. 4 is an AA' cross-sectional view of the double-sided pressure-sensitive adhesive sheet shown in FIG. 2. FIG. 5 is a diagram showing another example of the configuration of the second part. FIG. 6 is a diagram showing another example of the configuration of the second part. FIG. 7 is a diagram showing another example of the configuration of the second part. FIG. 8 is a diagram showing another example of the configuration of the second part. FIG. 9 is a schematic diagram showing the configuration of a double-sided pressure-sensitive adhesive sheet according to Embodiment 2 of the present disclosure. FIG. 10 is a diagram showing another example of a double-sided pressure-sensitive adhesive sheet according to Embodiment 2. FIG. 11 is a diagram showing another example of a double-sided pressure-sensitive adhesive sheet according to Embodiment 2. FIG. 12 is a diagram showing another example of a double-sided pressure-sensitive adhesive sheet according to Embodiment 2. FIG. 13 is a diagram showing an example of a method of using the double-sided pressure-sensitive adhesive sheet according to Embodiment 2.

[0009] [Embodiment 1] <Outline of double-sided pressure-sensitive adhesive sheet 1> Fig. 1 is a schematic diagram showing the configuration of a double-sided pressure-sensitive adhesive sheet 1 according to embodiment 1 of the present disclosure. Fig. 2 is a diagram showing a state in which a first separator 10, a pressure-sensitive adhesive layer 20, and a second separator 30 are laminated together in the double-sided pressure-sensitive adhesive sheet 1, and the first separator 10, which includes a first region 11 and a second region 12, is adhered to the second separator 30, which includes a third region 31 and a fourth region 32. Below, an outline of the double-sided pressure-sensitive adhesive sheet 1 according to the present disclosure will be described using Figs. 1 and 2 .

[0010] The double-sided pressure-sensitive adhesive sheet 1 is a double-sided pressure-sensitive adhesive sheet formed by laminating, in this order, a first separator 10, a pressure-sensitive adhesive layer 20 having a pressure-sensitive adhesive, and a second separator 30. The first separator 10 and the second separator 30 are sheets that protect the pressure-sensitive adhesive before use. The first separator 10 has, on its surface facing the pressure-sensitive adhesive layer 20, a first region 11 that is a part of that surface, and a second region 12 that is the region other than the first region 11. The second separator 30 has, on its surface facing the pressure-sensitive adhesive layer 20, a third region 31 that is at least a part of the region facing the second region 12, and a fourth region 32 that is the region other than the third region 31.

[0011] The pressure-sensitive adhesive layer 20 includes a first portion 21 provided between the first region 11 and the fourth region 32, and a second portion 22 provided between the second region 12 and the third region 31. In the double-sided pressure-sensitive adhesive sheet 1, the first region 11 is more difficult to peel from the pressure-sensitive adhesive layer 20 than the fourth region 32, and the third region 31 is more difficult to peel from the pressure-sensitive adhesive layer 20 than the second region 12.

[0012] When using the double-sided pressure-sensitive adhesive sheet 1, for example, after peeling off the second separator 30, the pressure-sensitive adhesive attached to the first separator 10 is adhered to a desired article, and then the first separator 10 is peeled off and another article is adhered to the bare side of the pressure-sensitive adhesive layer 20. Here, according to the double-sided pressure-sensitive adhesive sheet 1 of the present disclosure, the first region 11 is more difficult to peel from the pressure-sensitive adhesive layer 20 than the fourth region 32, and the third region 31 is more difficult to peel from the pressure-sensitive adhesive layer 20 than the second region 12. As a result, when the second separator 30 is peeled off, the pressure-sensitive adhesive in the first portion 21 remains adhered to the first separator 10, and the pressure-sensitive adhesive in the second portion 22 remains adhered to the second separator 30. This allows the pressure-sensitive adhesive provided on a single double-sided pressure-sensitive adhesive sheet 1 to be divided and used separately.

[0013] <Details of Double-Sided Pressure-Sensitive Adhesive Sheet 1> Details of the double-sided pressure-sensitive adhesive sheet 1 according to embodiment 1 will be described below with reference to Figures 1 to 5. Figure 3 is a diagram showing the double-sided pressure-sensitive adhesive sheet 1 in a state where the second separator 30 has been peeled off from the first separator 10. Figure 4 is a top view of the double-sided pressure-sensitive adhesive sheet 1 observed from the stacking direction (the direction from the second separator 30 toward the first separator 10). Note that the second separator 30 is not shown in Figure 4. Figure 5 is a cross-sectional view taken along line AA' of the double-sided pressure-sensitive adhesive sheet 1 shown in Figure 2.

[0014] The double-sided pressure-sensitive adhesive sheet 1 according to the first embodiment is configured to protect the first portion 21 from flying foreign matter by the second portion 22. As an example, as shown in Fig. 1 , when viewed from above in the stacking direction, the second portion 22 of the pressure-sensitive adhesive layer 20 is provided closer to the outer periphery of the first separator 10 and the second separator 30 than the first portion 21.

[0015] Foreign matter such as dust may be floating in the air in the space where the double-sided pressure-sensitive adhesive sheet 1 is present. Furthermore, when the double-sided pressure-sensitive adhesive sheet 1 is cut, fragments of the sheet may adhere to the edge of the double-sided pressure-sensitive adhesive sheet 1 as foreign matter. According to the above configuration, if foreign matter as described above enters between the first separator 10 and the second separator 30 before use of the double-sided pressure-sensitive adhesive sheet 1, the foreign matter will adhere to the second portion 22 before adhering to the first portion 21. Furthermore, when using the double-sided pressure-sensitive adhesive sheet 1, even if foreign matter is floating in the air when the second separator 30 is peeled off, the foreign matter is likely to adhere to the second portion 22 before adhering to the first portion 21. This reduces the possibility that foreign matter will be attached to the first portion 21 when the double-sided pressure-sensitive adhesive sheet 1 is used, and makes it possible to separately use the second portion 22, which is prone to foreign matter adhesion, and the first portion 21, which is resistant to foreign matter adhesion.

[0016] The material of the adhesive layer 20 is not particularly limited as long as it has adhesive properties. As an example, the first portion 21 of the adhesive layer 20 is an optically clear adhesive (OCA). When the first portion 21 is an optically clear adhesive, the double-sided adhesive sheet 1 is also referred to as an optical adhesive sheet. Note that the second portion 22 may be an adhesive made of the same material as the first portion 21, or an adhesive made of a different material. When the first portion 21 is an optically clear adhesive, the second portion 22 may be the same optically clear adhesive as the first portion 21, or an adhesive made of a different material.

[0017] Optical pressure-sensitive adhesive sheets are used to bond optical components such as display devices, sensor films, polarizing plates, cover films, and cover glasses of devices such as smartphones. The adhesive of the adhesive sheet (optical pressure-sensitive adhesive sheet) used to bond optical components is required to be optically transparent and transparent. It is undesirable for such optical pressure-sensitive adhesive sheets to have foreign matter attached thereto or scratches present. Therefore, if flying foreign matter adheres to the cross section or surface of the adhesive of the optical pressure-sensitive adhesive sheet, the optical pressure-sensitive adhesive sheet may become defective and unusable. Thus, there is a high need for optical pressure-sensitive adhesive sheets to suppress the adhesion of foreign matter to the adhesive, in particular.

[0018] Here, the double-sided pressure-sensitive adhesive sheet 1 according to the present disclosure includes the second portion 22. As a result, even if foreign matter gets between the first separator 10 and the second separator 30 during the period from the time of manufacture of the double-sided pressure-sensitive adhesive sheet 1 to the time of use, the foreign matter will adhere to the second portion 22 and will not adhere to the central first portion 21. Furthermore, when the second separator 30 is peeled off in order to use the double-sided pressure-sensitive adhesive sheet 1, any foreign matter that floats and flies in from outside the double-sided pressure-sensitive adhesive sheet 1 will adhere to the second portion 22, reducing the possibility of the foreign matter adhering to the central first portion 21.

[0019] Therefore, the double-sided pressure-sensitive adhesive sheet 1 according to the present disclosure can reduce the possibility of foreign matter adhering to the first portion 21, which is an optical pressure-sensitive adhesive used to bond optical components, thereby suppressing the occurrence of defects.

[0020] Note that there is a high possibility that foreign matter will adhere to the second portion 22. Therefore, even if the second portion 22 is an optical transparent adhesive, it is highly likely that it cannot be used to bond optical components together. Therefore, after the second separator 30 is peeled off, the second portion 22 may be discarded. However, the second portion 22, like the first portion 21, also has adhesive properties to objects. Therefore, the second portion 22 may be used for purposes other than bonding optical components together. For example, the second portion 22 may be used to bond components other than optical components in a terminal device having an optical component. Specifically, in a terminal device having a display, the first portion 21 may be used to bond a display device that displays the screen to a cover glass that protects the display device, and the second portion 22 may be used to bond other components together in locations that are not visible from the outside.

[0021] 1 to 4, the double-sided pressure-sensitive adhesive sheet 1 may include at least two second portions 22. In this case, as shown in Fig. 4, when the double-sided pressure-sensitive adhesive sheet 1 is viewed from above in the stacking direction, the two second portions 22 are provided between the long sides of the first portion 21 and the outer periphery of the first separator 10, at positions adjacent to each of the two long sides of the first portion 21, but at positions not in contact with the first portion 21. Furthermore, the two second portions 22 may have a length equal to or greater than the long sides of the first portion 21.

[0022] When double-sided adhesive sheet 1 is manufactured by pressing the long sides, chips from cutting or foreign matter adhering to the cutting blade are likely to adhere to the side surfaces of the long sides of double-sided adhesive sheet 1. Here, according to the above configuration, both side surfaces on the long sides of first portion 21 are protected by second portion 22. This reduces the possibility of foreign matter adhering to the side surfaces of first portion 21, even if foreign matter adheres to the side surfaces of the long sides of double-sided adhesive sheet 1.

[0023] 4 and 5, the first portion 21 is spaced apart from the second portion 22. The distance between the first portion 21 and the second portion 22 (the distance indicated by the symbol W1 in FIGS. 4 and 5) is, for example, 100 μm or more.

[0024] Because the first portion 21 and the second portion 22 are both adhesive, if the first portion 21 and the second portion 22 are in contact with each other, there is a possibility that the first portion 21 and the second portion 22 will not be properly separated when the second separator 30 is peeled off from the first separator 10. Therefore, it is preferable that the first portion 21 and the second portion 22 are at least spaced apart from each other.

[0025] Furthermore, the adhesive layer 20 may drip due to the nature of the material. If the distance between the first portion 21 and the second portion 22 is short, the adhesive of the first portion 21 and the second portion 22 may drip, causing the first portion 21 and the second portion 22 to adhere to each other. If the first portion 21 is spaced apart from the second portion 22 to a certain extent, the possibility of the first portion 21 and the second portion 22 adhering to each other is reduced, and the first portion 21 and the second portion 22 can be more reliably separated when the second separator 30 is peeled from the first separator 10. Note that, as long as the possibility of the first portion 21 and the second portion 22 adhering to each other is sufficiently low, the distance between the first portion 21 and the second portion 22 may be less than 100 μm.

[0026] As shown in FIGS. 4 and 5 , the second portion 22 is spaced from the outer peripheries of the first separator 10 and the second separator 30. The distance between the second portion 22 and the outer periphery of the first separator 10 (the distance indicated by symbol W2 in FIGS. 4 and 5 ) or the distance between the second portion 22 and the outer periphery of the second separator 30 (the distance indicated by symbol W3 in FIG. 5 ) is, for example, 1 μm or more. The double-sided pressure-sensitive adhesive sheet 1 may be delivered in multiple stacks, for example, 50 or more double-sided pressure-sensitive adhesive sheets 1. If the second portion 22 contacts the outer periphery of the first separator 10 or the second separator 30, the second portion 22 may protrude from the double-sided pressure-sensitive adhesive sheet 1 and adhere to other double-sided pressure-sensitive adhesive sheets 1 or other objects. Here, the second portion 22 of the double-sided pressure-sensitive adhesive sheet 1 is spaced from the outer peripheries of the first separator 10 and the second separator 30. This configuration reduces the possibility that second portion 22 will protrude from double-sided pressure-sensitive adhesive sheet 1, and reduces the possibility that second portion 22 will adhere to another double-sided pressure-sensitive adhesive sheet 1 or another article. Note that, if the possibility that second portion 22 will protrude from double-sided pressure-sensitive adhesive sheet 1 is sufficiently low, the distance between first portion 21 and second portion 22 may be less than 1 μm.

[0027] 6 to 10 are diagrams showing other examples of the configuration of the second portion 22 provided in the double-sided pressure-sensitive adhesive sheet 1. As shown in Fig. 1, the double-sided pressure-sensitive adhesive sheet 1 may have second portions 22 provided parallel to each of the long sides of the first portion 21 between the outside of the long sides and the outer periphery of the first separator 10, or may have second portions 22 of other shapes as shown in Figs.

[0028] 6 , two second portions 22 may be provided between each of the long sides of the first portion 21 and the outer periphery of the first separator 10. Increasing the number of second portions 22 can further reduce the possibility of foreign matter adhering to the first portions 21 when the second separator 30 is peeled off from the first separator 10.

[0029] 7, the second portion 22 may be provided between the short side of the first portion 21 and the outer periphery of the first separator 10. With this configuration, foreign matter flying toward the first portion 21 from the short side of the double-sided pressure-sensitive adhesive sheet 1 also adheres to the second portion 22, further reducing the possibility of foreign matter adhering to the first portion 21. Furthermore, as shown in FIG. 8, a plurality of second portions 22 may be provided between each of the long and short sides of the first portion 21 and the outer periphery of the first separator 10.

[0030] 9, when the double-sided pressure-sensitive adhesive sheet 1 is viewed from above in the stacking direction, the second portion 22 may surround the entire outer periphery of the first portion 21. In this case, the double-sided pressure-sensitive adhesive sheet 1 may be provided with only one second portion 22. According to the above configuration, the entire outer periphery of the first portion 21 is protected by the second portion 22. This further reduces the possibility of foreign matter adhering to the side surface of the first portion 21. Furthermore, as shown in FIG. 10, a plurality of second portions 22 may be provided, each surrounding the entire outer periphery of the first portion 21. By increasing the number of second portions 22, it is possible to further reduce the possibility of foreign matter adhering to the first portion 21 when the second separator 30 is peeled off from the first separator 10.

[0031] When the second portions 22 are provided as in FIGS. 6, 8, and 10, the distance between the second portions 22 is not particularly limited and may be, for example, 1 μm or more.

[0032] The shapes of the first separator 10, the second separator 30, the first portion 21, and the second portion 22 are not limited to those described above. For example, both the first separator 10 and the second separator 30 may be rectangular. Furthermore, when the first separator 10 and the second separator 30 are stacked together, a portion of the second separator 30 may protrude. Furthermore, the first portion 21 is not limited to a rectangular shape, and may be formed in any appropriate shape as needed. For example, the first portion 21 may be oval or another shape. Furthermore, the second portion 22 may be provided on at least a portion of the outer periphery of the first portion 21.

[0033] During production of the double-sided pressure-sensitive adhesive sheet 1, processing is performed on the surfaces of the first separator 10 and the second separator 30 to vary the peel resistance of the pressure-sensitive adhesive layer 20 between the first region 11 and the fourth region 32, and between the second region 12 and the third region 31. For example, a specific material is applied to the first separator 10 and the second separator 30 to form a release layer that adjusts the ease of peeling from the pressure-sensitive adhesive.

[0034] For example, when manufacturing the double-sided pressure-sensitive adhesive sheet 1, a material from which the adhesive does not easily peel is applied to the first region 11 of the first separator 10, and a material from which the adhesive does not easily peel is applied to the fourth region 32, thereby forming a film (release layer) from each material. Also, a material from which the adhesive does not easily peel is applied to the third region 31 of the second separator 30, and a material from which the adhesive does not easily peel is applied to the second region 12, thereby forming a film (release layer) from each material. Thereafter, a pressure-sensitive adhesive layer 20 is formed by applying a pressure-sensitive adhesive to the surface of the first separator 10, and the second separator 30 is further bonded to the pressure-sensitive adhesive layer 20, thereby manufacturing the double-sided pressure-sensitive adhesive sheet 1.

[0035] The film to be formed may be made of a material that makes the first region 11 less likely to peel from the adhesive layer 20 than the fourth region 32, and the third region 31 less likely to peel from the adhesive layer 20 than the second region 12. Furthermore, "hard to peel" and "easy to peel" are expressions that indicate relative ease of peeling, and it is sufficient that the first region 11 is less likely to peel from the adhesive layer 20 than the fourth region 32, and the third region 31 is less likely to peel from the adhesive layer 20 than the second region 12.

[0036] For example, the resistance of the first region 11 to the fourth region 32 to peeling from the adhesive layer 20 is expressed by the value of normal peel force [mM / mm]. The normal peel force is the force required to peel the object side at an angle of 180° at a predetermined speed (e.g., 300 mm / min) after leaving a sample in a state where the adhesive and the object are adhered together for a predetermined time (e.g., 24 hours). It can be said that the higher the normal peel force value, the more difficult it is to peel the object from the adhesive.

[0037] For example, the normal peel force for the first portion 21 of the first region 11 may be 400 mm / 50 mm, and the normal peel force for the first portion 21 of the fourth region 32 may be 56 mm / 50 mm. Also, the normal peel force for the second portion 22 of the second region 12 may be 60 mm / 50 mm, and the normal peel force for the second portion 22 of the third region 31 may be 120 mm / 50 mm.

[0038] When manufacturing the double-sided pressure-sensitive adhesive sheet 1, structures that will become multiple first separators 10 may be formed on a single sheet, a pressure-sensitive adhesive layer 20 may be formed on each first separator 10, and a single sheet on which structures that will become multiple second separators 30 may be formed may be stacked. These stacked sheets are then cut to produce multiple double-sided pressure-sensitive adhesive sheets 1. When cutting the sheet, the sheet may be cut by cutting a blade at the portion that will become the short side of the double-sided pressure-sensitive adhesive sheet 1 and moving the sheet. Alternatively, the portion that will become the long side of the double-sided pressure-sensitive adhesive sheet 1 may be cut by pressing it with another blade.

[0039] When double-sided pressure-sensitive adhesive sheet 1 is manufactured, it is in a state where first separator 10, pressure-sensitive adhesive layer 20, and second separator 30 are laminated together (the state shown in FIG. 2 ), and when it is used, second separator 30 is peeled off from first separator 10. Here, first region 11 is more difficult to peel off from pressure-sensitive adhesive layer 20 than fourth region 32, and third region 31 is more difficult to peel off from pressure-sensitive adhesive layer 20 than second region 12. Therefore, when second separator 30 is peeled off from double-sided pressure-sensitive adhesive sheet 1 in the state shown in FIG. 2 , first portion 21 adheres to first separator 10, and second portion 22 adheres to second separator 30 (the state shown in FIG. 3 ). When second separator 30 is peeled off from double-sided pressure-sensitive adhesive sheet 1, foreign matter adheres to second portion 22, reducing the possibility of foreign matter adhering to first portion 21.

[0040] With the second separator 30 peeled from the double-sided pressure-sensitive adhesive sheet 1, the first portion 21 adhered to the first separator 10 is adhered to one of the articles to be bonded, and then the first separator 10 is peeled from the first portion 21. This leaves only the first portion 21 adhered to the article. Then, by adhering the other of the articles to be bonded to the first portion 21, the two articles are adhered to each other by the first portion 21. In this way, articles can be bonded to each other using the first portion 21, which has a reduced possibility of foreign matter adhering to it.

[0041] The materials described in paragraph 0042 of Patent Document 1 may be used as the materials for the first separator 10 and the second separator 30. The materials described in paragraph 0045 of Patent Document 1 may be used as the materials for the release layers provided on the first separator 10 and the second separator 30. At least the first portion 21 of the pressure-sensitive adhesive layer 20 may be formed using the substances and methods described in paragraphs 0042 to 0105 of Patent Document 1 or paragraphs 0034 to 0046 of JP-A No. 2018-51169.

[0042] [Embodiment 2] Another embodiment of the present disclosure will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0043] In the first embodiment, the first portion 21 is an optical transparent adhesive, and the second portion 22 protects the first portion 21 from flying foreign matter, but the present invention is not limited to this. The first portion 21 may be separated from the second portion 22 when the second separator 30 is peeled off from the first separator 10.

[0044] FIG. 11 is a schematic diagram showing the configuration of a double-sided pressure-sensitive adhesive sheet 1A according to a second embodiment of the present disclosure. As shown in FIG. 11 , when the second separator 30 is peeled from the first separator 10 in the double-sided pressure-sensitive adhesive sheet 1A, the first portion 21 adheres to the first separator 10, and the second portion 22 adheres to the second separator 30. The double-sided pressure-sensitive adhesive sheet 1A may be made of the same materials as the adhesive and separator of a conventionally used double-sided tape. For example, the first separator 10 and the second separator 30 of the double-sided pressure-sensitive adhesive sheet 1A may be made of the same materials as the first separator 10 and the second separator 30 of the double-sided pressure-sensitive adhesive sheet 1 according to the first embodiment. Furthermore, the first separator 10 and the second separator 30 of the double-sided pressure-sensitive adhesive sheet 1A may be made of the materials described in paragraphs 0074 and 0075 of JP 2020-2282 A, or may be made of other materials. The pressure-sensitive adhesive layer 20 of the double-sided pressure-sensitive adhesive sheet 1A may be made of the same material as the pressure-sensitive adhesive layer 20 of the double-sided pressure-sensitive adhesive sheet 1 according to embodiment 1. The pressure-sensitive adhesive layer 20 of the double-sided pressure-sensitive adhesive sheet 1A may be made of the material described in paragraphs 0038 to 0069 of JP 2020-2282 A, or may be made of other materials.

[0045] According to this configuration, one double-sided adhesive sheet 1A can be used to adhere item A and item B together using the first portion 21, and to adhere item C and item D together using the second portion 22.

[0046] 12 to 14 are diagrams showing other examples of double-sided pressure-sensitive adhesive sheet 1A. As shown in Fig. 12, double-sided pressure-sensitive adhesive sheet 1A may have a plurality of first portions 21 and a plurality of second portions 22. Furthermore, when first separator 10 and second separator 30 of double-sided pressure-sensitive adhesive sheet 1A are laminated, first portion 21 and second portion 22 may be in contact with each other or may be spaced apart. Furthermore, the boundary line between first portion 21 and second portion 22 may be a straight line as shown in Fig. 11, a dashed line, or another shape.

[0047] 11, the first portion 21 and the second portion 22 may have the same shape, or as shown in Figures 13 and 14, the first portion 21 and the second portion 22 may have different shapes. The shapes of the first portion 21 and the second portion 22 may be adjusted depending on the intended use of each portion.

[0048] For example, as shown in Fig. 14, the shape of the first portion 21 may be the shape of a portion cut out of a single sheet, and the shape of the second portion 22 may be the shape of a portion cut out of the single sheet. Fig. 15 is a diagram showing an example of how to use the double-sided pressure-sensitive adhesive sheet 1A. As shown in Fig. 15, when bonding a concave-shaped item X and a convex-shaped item Y together, the first portion 21 can be used to bond the portion indicated by reference numeral 1501, and the second portion 22 can be used to bond the portion indicated by reference numeral 1502. In this way, with the double-sided pressure-sensitive adhesive sheet 1A, it is possible to bond items with complex shapes using only a single sheet.

[0049] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0050] 1, 1A Double-sided pressure-sensitive adhesive sheet 10 First separator 11 First region 12 Second region 20 Pressure-sensitive adhesive layer 21 First portion 22 Second portion 30 Second separator 31 Third region 32 Fourth region

Claims

1. A double-sided pressure-sensitive adhesive sheet having a first separator, a pressure-sensitive adhesive layer having a pressure-sensitive adhesive, and a second separator laminated in this order, wherein the first separator has, on its surface facing the pressure-sensitive adhesive layer, a first region that is a part of said surface, and a second region that is a region other than the first region; the second separator has, on its surface facing the pressure-sensitive adhesive layer, a third region that is at least a part of the region facing the second region, and a fourth region that is a region other than the third region; the pressure-sensitive adhesive layer has a first portion provided between the first region and the fourth region, and a second portion provided between the second region and the third region; the first region is more difficult to peel from the pressure-sensitive adhesive layer than the fourth region, and the third region is more difficult to peel from the pressure-sensitive adhesive layer than the second region.

2. The double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the second portion is provided closer to the outer periphery of the first separator and the second separator than the first portion.

3. The double-sided pressure-sensitive adhesive sheet according to claim 2, wherein the first portion is an optically transparent pressure-sensitive adhesive.

4. The double-sided adhesive sheet according to claim 3, comprising at least two of the second portions, wherein, when the double-sided adhesive sheet is viewed from above in the stacking direction, the two second portions are located adjacent to two long sides of the first portion, respectively, and the two second portions are longer than or equal to the long sides of the first portion.

5. The double-sided pressure-sensitive adhesive sheet according to claim 3, wherein, when the double-sided pressure-sensitive adhesive sheet is viewed from above in the stacking direction, the second portion surrounds the entire outer periphery of the first portion.

6. The double-sided pressure-sensitive adhesive sheet according to any one of claims 3 to 5, wherein the first portion is spaced apart from the second portion.

7. The double-sided pressure-sensitive adhesive sheet according to any one of claims 3 to 6, wherein the second portion is spaced apart from the outer peripheries of the first separator and the second separator.

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