Adhesive sheet

Abstract

To provide a pressure sensitive adhesive sheet excellent in designability while securing a conduction path for air bubble removal.SOLUTION: A pressure sensitive adhesive sheet 1 includes: an extensible film layer 10; an adhesive layer 15 formed on one face side of the extensible film layer; a releasable sheet 18 formed on the opposite face side of the extensible film layer of the adhesive layer; and a groove part 16 formed on the opposite face side of the extensible film layer of the adhesive layer. The groove part may be terminated at an outer peripheral part of the adhesive layer, or may be communicating with another groove part that is terminated at an outer peripheral portion of the adhesive layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pressure-sensitive adhesive sheet. [Background technology]

[0002] Conventionally, in pressure-sensitive adhesive sheets that can be attached to an adherend without using adhesive by virtue of a pressure-sensitive adhesive layer provided on the sheet, preventing the infiltration of air bubbles during adhesion has been an issue. In response to this, a pressure-sensitive adhesive sheet has been proposed that is capable of removing air bubbles from voids in the protrusions by providing protrusions in the pressure-sensitive adhesive layer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-336017 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, providing voids in the pressure-sensitive adhesive layer causes unevenness on the surface of the pressure-sensitive adhesive sheet, which impairs the design.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a pressure-sensitive adhesive sheet that has excellent design properties while ensuring a conduction path for removing air bubbles. [Means for solving the problem]

[0006] In order to solve the above problems, an adhesive sheet according to one embodiment of the present invention comprises a stretchable film layer, an adhesive layer formed on one side of the stretchable film layer, and a peelable sheet formed on the side of the adhesive layer opposite the stretchable film layer, and has a groove portion formed on the side of the adhesive layer opposite the stretchable film layer, the groove portion terminating at the outer periphery of the adhesive layer or being connected to another groove portion terminating at the outer periphery of the adhesive layer. Effect of the Invention

[0007] According to one aspect of the present invention, it is possible to provide a pressure-sensitive adhesive sheet that has excellent design while ensuring a conductive path for removing air bubbles. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view that illustrates a schematic configuration example of a pressure-sensitive adhesive sheet according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a perspective view showing a schematic configuration example of a printed resin film according to a first embodiment of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view that illustrates a schematic configuration example of a pressure-sensitive adhesive sheet according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a pressure-sensitive adhesive sheet according to one embodiment of the present invention will be described with reference to the drawings. Here, the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc. are different from the actual ones. In addition, the embodiments shown below are examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the materials, shapes, structures, etc. of the components described below. The technical idea of ​​the present invention can be variously modified within the technical scope defined by the claims described in the claims.

[0010] First Embodiment (Adhesive sheet) The basic configuration of the pressure-sensitive adhesive sheet according to the first embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view for illustrating one configuration example of the pressure-sensitive adhesive sheet 1 according to the first embodiment of the present disclosure. As shown in Fig. 1, an adhesive sheet 1 according to one embodiment of the present invention comprises a stretchable film layer 10 and an adhesive layer 15 formed on one side (hereinafter referred to as "reverse side 10b") of the stretchable film layer 10. A release sheet 18 is attached to the side (hereinafter referred to as "reverse side 15b") of the adhesive layer 15 opposite the stretchable film layer 10. The adhesive sheet 1 is suitable for use as wallpaper, for example.

[0011] <Expandable film layer> The extensible film layer 10 includes a first base layer 11, a second base layer 13 disposed on the surface of the first base layer 11 opposite to the adhesive layer 15, and a pattern layer 12 disposed between the first base layer 5 and the second base layer 6. The extensible film layer 10 is formed so that the hiding ratio based on JIS K 5600-4-1 is 0.8 or more. An example in which a surface protective layer 14 is disposed on the surface 13a of the extensible film layer 10 on the second base layer 13 side will be described, but the present invention is not limited to this configuration. For example, the surface protective layer 14 may not be provided.

[0012] (first base layer) The first base material layer 11 is a sheet-like member that, together with the second base material layer 13, forms the base of the adhesive sheet 1. Examples of materials that can be used for the first base material layer 11 include resins that have excellent heat resistance, fire resistance, and mechanical strength, such as polypropylene resin, acrylonitrile-butadiene-styrene copolymer, and polycarbonate. In addition, the thickness of the first base layer 11 is preferably 50 μm or more and 150 μm or less in order to provide the desired physical properties such as sufficient strength while satisfying the required hiding power. When the thickness is 50 μm or more, the physical properties such as strength and hiding power are improved. When the thickness is 150 μm or less, other physical properties such as fire resistance are improved. The first base layer 11 preferably has a hiding ratio of 0.8 or more based on JIS K 5600-4-1. When the hiding ratio of the first base layer 11 is 0.8 or less, the pattern layer 12 and the second base layer 13 having hiding properties may be used so that the extensible film layer 10 has a hiding ratio of 0.8 or more.

[0013] (Second base layer) The second base layer 13 is a sheet-like member which, together with the first base layer 11, forms the base of the adhesive sheet 1. As with the film of the first base layer 11, the resin constituting the second base layer 13 may be, for example, polypropylene resin, acrylonitrile-butadiene-styrene copolymer, polycarbonate, etc., from the standpoint of heat resistance, cold resistance, and mechanical strength. In addition, the second base layer 13 has a transparency that allows the pattern layer 12 to be visually recognized. The thickness of the second base layer 13 is preferably 50 μm or more and 100 μm or less in order to impart the desired sufficient elasticity and impact resistance while satisfying other physical properties such as fire resistance. In addition, in this embodiment, an example in which the second base material layer 13 is provided will be described, but the present invention is not limited to this configuration. For example, the second base material layer 13 may not be provided as necessary.

[0014] (Picture layer) The picture layer 12 is a layer for decorating the surface side of the adhesive sheet 1 with a picture pattern. The picture layer 12 is a coating of printing ink formed by printing a picture pattern on the surface 11a of the first base material layer 11. There are no particular limitations on the printing ink as long as it satisfies the requirements of light resistance, color development, and safety of the ingredients used that are generally required for wallpaper. Examples of safety requirements include materials that do not contain heavy metals or sulfur compounds as pigments or additives. The thickness of the pattern layer 12 may be any thickness that allows the desired design to be fully expressed. The thickness of the pattern layer 12 is preferably in the range of, for example, 0.1 μm to 10 μm. In this embodiment, the design layer 12 is provided on the surface 11a of the first base layer 11, but the present invention is not limited to this configuration. For example, the design layer 12 may not be provided as necessary.

[0015] (Surface protective layer) The surface protective layer 14 is a layer for protecting the first base material layer 5 and the pattern layer 12. The surface protective layer 14 has transparency that allows the pattern layer 12 to be visually recognized, and has physical properties such as sufficient strength, stain resistance, and weather resistance required for protection. For example, the surface protective layer 14 is formed by applying a coating agent containing a solvent such as methyl ethyl ketone, a polyurethane resin, and an isocyanate curing agent to the surface of the second base material layer 13 opposite the pattern layer 12 (hereinafter referred to as "surface 13a"), drying the coating agent, and then curing the coating agent by ultraviolet irradiation. In addition, other resins such as acrylic resin coating agents may be used as the resin constituting the surface protective layer 14. The basis weight of the surface protective layer 14 is set to 2.0 g / m2 from the viewpoint of high surface strength. 2 More than 7.0g / m 2 It is preferable that:

[0016] In addition, the surface of the surface protective layer 14, which is the outermost layer of the adhesive sheet 1, may be embossed (roughness-imparting using an embossing plate) to form (impart) an embossed pattern. In this case, the embossed pattern formed on the surface of the surface protective layer 14 can be configured to give a more three-dimensional feel to the touch. In the embossing process, for example, a concave shape having a depth of 15 μm or more may be passed between an embossing roll and a rubber back roll having a hardness of 50 degrees or more and less than 90 degrees to give the adhesive sheet 1 a rough shape. As a method for measuring hardness, for example, the measurement method shown in JIS K-6253 may be mentioned. Examples of embossed patterns include wood grain duct grooves, stone slab surface roughness, cloth surface texture, matte finish, sand grain, hairline, and stripe grooves. As described later, the embossing process may be omitted and no embossed pattern may be applied.

[0017] <Adhesive layer> The adhesive layer 15 is a layer for imparting adhesiveness to the extensible film layer 10. The back surface 15b of the adhesive layer 15 is formed with unevenness that matches the shape of the printed resin film 17 described later, and a plurality of grooves 16 are formed as recesses. Each groove 16 terminates at the outer periphery of the adhesive layer 15, or communicates with other grooves 16 that terminate at the outer periphery of the adhesive layer 15. This allows air trapped between the adhesive layer 15 and the adherend to flow out to the surroundings when the adhesive sheet 1 is attached to the adherend. After the air has flowed out to the surroundings, the bottom of the groove 16 is brought into close contact with the surface of the adherend, and the groove 16 can disappear. In addition, by bringing the bottom of the groove 16 into close contact with the surface of the adherend, it is possible to improve impact resistance and cold resistance.

[0018] The cross-sectional shape of the groove 16 may be, for example, a V-shape, a U-shape, a rectangle, or a trapezoid. The volume occupied by the groove 16 is, for example, 1×10 per area of ​​a circle of the adhesive layer 15 having a diameter of 500 μm. 3 μm 3 The depth of the deepest part of the groove portion 16 is desirably 3 μm or more and 10 μm or less in order to prevent unevenness from occurring on the surface of the adhesive sheet 1 due to the conductive path for removing air bubbles. When the depth is 3 μm or more, air trapped between the adhesive layer 15 and the adherend can be suitably discharged, improving the air release performance. On the other hand, when the depth is 10 μm or less, the impact resistance of the adhesive sheet 1 is improved.

[0019] As a method for forming the grooves 16, for example, a method of forming the grooves 16 by attaching a release sheet 18 having projections and recesses for forming the grooves 16 is preferable. Alternatively, for example, a method of forming the grooves 16 by uniformly applying an adhesive to the back surface 10b of the first base layer 11 of the extensible film layer 10 and then embossing the adhesive using a mold having projections and recesses for forming the grooves 16 can be used.

[0020] An acrylic pressure-sensitive adhesive using acrylic acid or an acrylic acid ester as a starting material is used as the adhesive composition constituting the adhesive layer 15. As the acrylic pressure-sensitive adhesive, for example, adhesives disclosed in U.S. Pat. Nos. 3,239,478, 3,935,338, 5,169,727, Reissue Patent No. 24906, 4,952,650, and 4,181,752 can be used. In addition, as a method for applying the adhesive composition, for example, roll coating or knife coating can be used.

[0021] In addition, the thickness of the thickest part of the adhesive layer 15, i.e., the thickness of the part where the groove portion 16 is not present, is preferably 20 μm or more at the stage after the adhesive composition has been applied and dried, in order to provide ease of application and sufficient adhesive strength while balancing the thickness with the printed resin film 17 described below. From the viewpoints of impact resistance and air release performance, the maximum height difference of the pressure-sensitive adhesive layer 15 is preferably 3% to 50% of the thickness of the thickest part of the pressure-sensitive adhesive layer 15. When it is 3% or more, air trapped between the pressure-sensitive adhesive layer 15 and the adherend can be discharged, improving the air release performance. On the other hand, when it is 50% or less, no unevenness of the conductive paths is formed on the surface of the pressure-sensitive adhesive sheet 1, improving the design.

[0022] <Removable sheet> The release sheet 18 is a sheet-like member that is attached to the pressure-sensitive adhesive layer 15. As the release sheet 18, for example, a laminate in which a release layer mainly made of silicone resin or the like is laminated on the surface of an appropriate base material such as a plastic film or paper, a polyolefin resin film such as a polyethylene film, or a polyethylene terephthalate resin film can be used.

[0023] <Printed resin film> FIG. 2 is a perspective view from an upper oblique direction that shows a schematic configuration example of the printed resin film according to the first embodiment of the present invention. As shown in FIG. 2, the printed resin film 17 is a convex portion formed on the surface 18a of the peelable sheet 18 on the side of the adhesive layer 15, which fits into the groove portion 16. The material constituting the printed resin film 17 is not particularly limited as long as it has a weak adhesive property with the peelable sheet 18 and can print a pattern having continuous openings on the peelable sheet 18. In addition, as the material constituting the printed resin film 17, a material that can maintain the printed resin film 17 for a long period of time without being affected by the solvent such as acrylic or toluene of the adhesive composition constituting the adhesive layer 15 is used. For example, as the material constituting the printed resin film 17, a polyurethane resin mixed with a solvent such as methyl ethyl ketone can be used.

[0024] As a method for forming the printed resin film 17, for example, a method of applying the resin film 17 by gravure printing can be used. Other printing methods such as flexographic printing, offset printing, screen printing, and rotary printing can also be used. 。

[0025] The printed resin film 17 terminates at the outer periphery of the release sheet 18 in accordance with the shape of the groove 16 described above, or is connected to another printed resin film 17 that terminates at the outer periphery of the release sheet 18. As shown in FIG. 2, the printed resin film 17 is formed, for example, in a lattice shape on the release sheet 18. When the printed resin film 17 is formed in a lattice shape, it is preferable that the printed resin film 17 is arranged parallel to the longitudinal direction of the release paper at an inclination angle of 30° to 60°. In addition, the length of one side of the adhesive portion 25 provided between the groove 16 and another groove 16 in the adhesive layer 15 is preferably 2 mm to 30 mm. In addition, the width of the printed resin film 17 is preferably 1 mm to 15 mm. By forming the printed resin film 17 in a lattice pattern, the adhesive sheet 1 can be adhered to the adherend without allowing air bubbles to get in. Furthermore, the adhesive sheet 1 can be peeled off without leaving any traces even after a long period of time has passed since it was adhered.

[0026] When the printed resin film 17 is formed in a lattice pattern, the grooves 16 in the adhesive layer 15 are also formed in a lattice pattern. As a result, the adhesive portions 25 provided between the grooves 16 in the adhesive layer 15 are formed in independent polygonal shapes (e.g., quadrilaterals). More specifically, the printed resin film 17 is formed in a lattice pattern by being arranged at equal intervals and parallel to the longitudinal direction of the peelable sheet 18 at an inclination angle of 45° as shown in Fig. 2. The length of one side of the adhesive portion 25 is 4 mm, and the width of the printed resin film 17 is 2 mm. In this case, the adhesive portion 25 is formed in a square shape. Alternatively, the printed resin film 17 may be formed in a stripe shape, a T-shape, or the like.

[0027] The thickness of the printed resin film 17 is desirably 3 μm or more and 10 μm or less to prevent unevenness on the surface of the adhesive sheet 1 caused by the conductive paths for removing air bubbles. When the thickness is 3 μm or more, the air trapped between the adhesive layer 15 and the adherend can be suitably discharged, improving the air removal performance. On the other hand, when the thickness is 10 μm or less, unevenness due to the conductive paths is not formed on the surface of the adhesive sheet 1, improving the design.

[0028] <Advantages of the First Embodiment> The adhesive sheet 1 according to this embodiment has the following effects. (1) The pressure-sensitive adhesive sheet 1 of the present embodiment has grooves 16 on the surface 15b of the pressure-sensitive adhesive layer 15 opposite the extensible film layer 10. This configuration can improve impact resistance and air bleeding performance.

[0029] (2) The pressure-sensitive adhesive sheet 1 of the present embodiment is formed so that the extensible film layer 10 has a hiding ratio based on JIS K 5600-4-1 of 0.8 or more. According to this configuration, the conductive path for removing air bubbles can be concealed, and a higher design quality can be achieved.

[0030] (3) In adhesive sheet 1 of the present embodiment, grooves 16 are formed so that their deepest portion has a depth of 3 μm or more and 10 μm or less. This configuration makes it possible to effectively remove air bubbles while preventing the formation of irregularities on the surface of the adhesive sheet 1, thereby achieving higher designability.

[0031] <Second embodiment> The adhesive sheet according to the second embodiment of the present disclosure will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view for illustrating one configuration example of the adhesive sheet 1 according to the second embodiment of the present disclosure. The surface protective layer 14 of this embodiment differs from the surface protective layer 14 shown in Fig. 1 in that the embossing is omitted and an embossed pattern is not applied. In this figure, the same components as those shown in Fig. 1 are denoted by the same reference numerals. In the adhesive sheet 1 according to the second embodiment of the present disclosure, by omitting the embossing of the surface protective layer 14, it is possible to ensure a conductive path for removing air bubbles, thereby preventing the design from being impaired by the conductive path and improving the efficiency of adhesive sheet production. EXAMPLES

[0032] [Example 1] First, a colored polypropylene film (manufactured by RIKEN TECHNOS, OW) having a thickness of 30 μm and a hiding rate based on JIS K 5600-4-1 of 0.7 was prepared as the first substrate layer. Then, a pattern layer was formed by applying the ink to the surface of the first substrate layer by gravure printing so as to cover the entire surface of the first substrate layer. As the printing ink, an acrylic resin-based oil-based ink (manufactured by Toyo Ink Mfg. Co., Ltd., product name: V351UR-T series) was used. Then, an uncolored polypropylene film (manufactured by Prime Polymer Co., Ltd., CPS-DB) having a thickness of 80 μm was laminated on the upper layer of the pattern layer as the second substrate layer. Then, an acrylic resin-based coating agent (manufactured by Dainichiseika Color & Chemicals Co., Ltd., W-480E) was applied to the surface of the second substrate layer by gravure printing to form a surface protection layer. The amount of the acrylic resin-based coating agent applied was 6.0 g / m2 in terms of dry weight. 2In this way, a stretchable film layer was produced. The hiding ratio of the stretchable film layer based on JIS K 5600-4-1 was set to 0.7.

[0033] Next, an acrylic pressure-sensitive adhesive (BPS6113, Toyo Ink Manufacturing Co., Ltd.) was applied and dried on the back surface of the extensible film layer by a coating machine to form an adhesive layer. The thickness of the thickest part of the adhesive layer after drying was 10 μm. Next, a laminated sheet with a thickness of 120 μm was prepared as a release sheet. As the laminated sheet, a sheet (SHA80, San-A Chemical Co., Ltd.) was used in which a release layer mainly made of silicone resin or the like was laminated on the upper layer of a polypropylene film layer and a paper layer was laminated on the lower layer of the polypropylene film layer. Next, an ether-based polyurethane resin (Sakata Inx Corporation, Sapiriah) was applied to the surface of the release sheet by gravure printing to form a printed resin film in a lattice shape. The thickness of the printed resin film after drying was 1 μm. Next, the release sheet was pressure-bonded to the adhesive layer. As a result, multiple grooves were formed on the back surface of the adhesive layer. The depth of the deepest part of the groove (the maximum height difference of the adhesive layer) was 1 μm, that is, the ratio of the maximum height difference of the adhesive layer to the thickness of the thickest part of the adhesive layer was 10%. In this manner, the pressure-sensitive adhesive sheet of Example 1 was produced.

[0034] [Example 2] The thickness of the printed resin film after drying was 3 μm. In other words, the depth of the deepest part of the groove (the maximum height difference of the adhesive layer) was 3 μm. Accordingly, the ratio of the maximum height difference of the adhesive layer to the thickness of the thickest part of the adhesive layer was 30%. The adhesive sheet of Example 2 was produced using the same materials and procedures as Example 1 except for the above.

[0035] [Example 3] The thickness of the printed resin film after drying was 10 μm. In other words, the depth of the deepest part of the groove (the maximum height difference of the adhesive layer) was 10 μm. Accordingly, the ratio of the maximum height difference of the adhesive layer to the thickness of the thickest part of the adhesive layer was 100%. The adhesive sheet of Example 3 was produced using the same materials and procedures as Example 1 except for the above.

[0036] [Example 4] The thickness of the thickest part of the adhesive layer after drying was 20 μm. Accordingly, the ratio of the maximum height difference of the adhesive layer to the thickness of the thickest part of the adhesive layer was 30%. The adhesive sheet of Example 4 was produced using the same materials and procedures as Example 1 except for the above.

[0037] [Example 5] The first base layer had a hiding ratio based on JIS K 5600-4-1 of 0.8. Accordingly, the extensible film layer had a hiding ratio based on JIS K 5600-4-1 of 0.8. Except for this, the pressure-sensitive adhesive sheet of Example 5 was produced using the same materials and procedures as Example 1.

[0038] [Example 6] The thickness of the first base layer was set to 50 μm. Otherwise, the pressure-sensitive adhesive sheet of Example 6 was produced using the same materials and procedures as in Example 1.

[0039] [Example 7] The thickness of the first base layer was 150 μm. Except for that, the adhesive sheet of Example 7 was produced using the same materials and procedures as in Example 1.

[0040] [Example 8] The first base layer was changed from a 30 μm thick colored polypropylene film to a 50 μm thick uncolored polypropylene film (CPS-DB, manufactured by Prime Polymer Co., Ltd.). The formation of the second base layer was omitted. Next, the density of the pattern layer was adjusted to set the concealment rate of the extensible film layer based on JIS K 5600-4-1 to 0.8. Next, the thickness of the thickest part of the adhesive layer after drying was set to 20 μm. Also, the thickness of the printed resin film after drying was set to 3 μm. That is, the depth of the deepest part of the groove part (the maximum height difference of the adhesive layer) was set to 3 μm. Accordingly, the ratio of the maximum height difference of the adhesive layer to the thickness of the thickest part of the adhesive layer was 1.5%. The adhesive sheet of Example 8 was produced using the same materials and procedures as Example 1 except for the above.

[0041] [Example 9] The first base layer was a colored polypropylene film with a hiding rate of 0.94 based on JIS K 5600-4-1. The formation of a pattern layer was omitted. Accordingly, the hiding rate of the extensible film layer based on JIS K 5600-4-1 was set to 0.94. Subsequently, the thickness of the thickest part of the adhesive layer after drying was set to 40 μm. Accordingly, the ratio of the maximum height difference of the adhesive layer to the thickness of the thickest part of the adhesive layer was 7.5%. The adhesive sheet of Example 9 was produced using the same materials and procedures as Example 8 except for the above.

[0042] [Example 10] The thickness of the printed resin film after drying was 10 μm. In other words, the depth of the deepest part of the groove (the maximum height difference of the adhesive layer) was 10 μm. Accordingly, the ratio of the maximum height difference of the adhesive layer to the thickness of the thickest part of the adhesive layer was 50%. The adhesive sheet of Example 10 was produced using the same materials and procedures as Example 8 except for the above.

[0043] [Example 11] The first base layer was a colored polypropylene film having a thickness of 70 μm and a hiding ratio based on JIS K 5600-4-1 of 0.94. Accordingly, the extensible film layer had a hiding ratio based on JIS K 5600-4-1 of 0.94. Subsequently, the thickness of the thickest part of the adhesive layer after drying was 40 μm. In addition, the thickness of the printed resin film after drying was 3 μm. That is, the depth of the deepest part of the groove (the maximum height difference of the adhesive layer) was 3 μm. Accordingly, the ratio of the maximum height difference of the adhesive layer to the thickness of the thickest part of the adhesive layer was 7.5%. The adhesive sheet of Example 11 was produced using the same materials and procedures as Example 1 except for the above.

[0044] [Comparative Example 1] The formation of the grooves was omitted. Except for this, the adhesive sheet of Comparative Example 1 was produced using the same materials and procedures as in Example 11.

[0045] (evaluation) For the pressure-sensitive adhesive sheets of Examples 1 to 11 and Comparative Example 1 obtained by the above-mentioned methods, a visual evaluation of the conductive paths, an evaluation of surface irregularities, and an air-bleeding performance confirmation test were carried out.

[0046] [Visual inspection of electrical pathways] After the test piece was attached to the SUS plate, it was immediately checked under a D65 light source whether the conductive path was visible or not, and rated on the following four levels: ◎, ◯, △, ×. ◎: No conductive path is visible at all ○: The conductive path is almost invisible △: The conductive path is faintly visible ×: The entire conductive path is visible.

[0047] [Surface roughness evaluation] After attaching the test piece to the SUS plate, the surface of the test piece was touched with a finger and the state of surface unevenness was evaluated using the following four levels: ◎, ◯, △, ×. ⊚: The surface is completely free of irregularities and feels smooth. ◯: Almost no unevenness on the surface is felt. △: Some parts of the surface feel uneven. ×: Irregularities are felt along the shape of the conductive path.

[0048] [Air bleeding performance confirmation test] The test piece was attached to the SUS plate so that air bubbles were trapped inside. Immediately afterwards, the air bubbles were removed using a squeegee. The surface condition of the test piece was then visually observed and rated on the following four-level scale: ◎, 〇, △, ×. ◎: Air bubbles are completely removed ○: Small air bubbles can be seen, but most of the air bubbles have been removed. △: Several small air bubbles can be seen, but most of the air bubbles have been removed. ×: Air bubbles are not removed and many air bubbles remain

[0049] (Evaluation Results) Table 1 below shows the configuration of the pressure-sensitive adhesive sheets of each of the Examples and Comparative Examples, as well as the results of visual evaluation of the conductive paths, evaluation of surface irregularities, and the air-bleeding performance confirmation test for each of the Examples and Comparative Examples.

[0050] [Table 1]

[0051] As shown in Table 1, the evaluation results of Examples 1 to 11 and Comparative Example 1 show that when grooves are formed in the adhesive layer as in Examples 1 to 11, the adhesive layer has higher air-release performance than when no grooves are formed as in Comparative Example 1.

[0052] Furthermore, the evaluation results comparing Example 1 with Examples 5 to 7 showed that by setting the concealment rate of the extensible film layer to 0.8 or more and setting the thickness of the first base layer to 50 μm or more and 150 μm or less, the conductive path becomes invisible, thereby improving the design.

[0053] Furthermore, the evaluation results comparing Example 1 with Examples 4, 6, and 7 showed that by making the thickness of the thickest part of the adhesive layer 20 μm or more and making the thickness of the first base layer 50 μm or more and 150 μm or less, unevenness on the surface of the adhesive sheet due to the conductive paths is prevented from being formed, improving the design.

[0054] The pressure-sensitive adhesive sheet of the present invention is not limited to the above-mentioned embodiments and examples, and various modifications are possible without departing from the characteristics of the invention. [Explanation of symbols]

[0055] 1...Adhesive sheet 10...Extensible film layer 11...First base material layer 12...Pattern layer 13...Second base material layer 14…Surface protective layer 15...Adhesive layer 16…Groove 17...Printed resin film 18...Removable sheet

Claims

1. A stretchable film layer; A pressure-sensitive adhesive layer formed on one side of the extensible film layer; a release sheet formed on the side of the pressure-sensitive adhesive layer opposite the extensible film layer; Equipped with A groove is formed on the surface of the pressure-sensitive adhesive layer opposite to the extensible film layer, the groove portion terminates at the outer peripheral portion of the pressure-sensitive adhesive layer or communicates with another groove portion that terminates at the outer peripheral portion of the pressure-sensitive adhesive layer, a printed resin film provided on a portion of the surface side of the pressure-sensitive adhesive layer of the release sheet so as to fill the grooves; The printed resin film is formed of a polyurethane resin, On the surface of the pressure-sensitive adhesive layer of the release sheet, an area on which the printed resin film is not provided is in contact with the pressure-sensitive adhesive layer, The pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive and has a thickness of 20 μm or more at its thickest portion, A pressure-sensitive adhesive sheet, characterized in that the thickness of the printed resin film is 3 μm or more and 10 μm or less.

2. The pressure-sensitive adhesive sheet according to claim 1 , wherein the printed resin film is formed from an ether-based polyurethane resin.

3. 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the printed resin film is formed in any one of a lattice pattern, a stripe pattern, and a T-shape on the release sheet.

4. 4. The pressure-sensitive adhesive sheet according to claim 1, wherein the maximum height difference of the pressure-sensitive adhesive layer is 3% to 50% of the thickness of the thickest part of the pressure-sensitive adhesive layer.

5. The pressure-sensitive adhesive sheet according to claim 1 , wherein the pressure-sensitive adhesive layer has a maximum height difference of 3 μm to 10 μm.

6. The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the extensible film layer has a hiding ratio based on JIS K 5600-4-1 of 0.8 or more.

7. The extensible film layer includes a first base material layer, a second base material layer disposed on a surface of the first base material layer opposite to the pressure-sensitive adhesive layer, and a pattern layer disposed between the first base material layer and the second base material layer, The pressure-sensitive adhesive sheet according to claim 1 , wherein the first base layer has a thickness of 50 μm or more and 150 μm or less.

8. the first base layer is a layer formed of a polypropylene resin, an acrylonitrile-butadiene-styrene copolymer, or a polycarbonate resin; 8. The pressure-sensitive adhesive sheet according to claim 7, wherein the second base layer is a layer formed of a polypropylene resin, an acrylonitrile-butadiene-styrene copolymer, or a polycarbonate resin.

9. The first base layer is a polypropylene film layer, The second base layer is a polypropylene film layer, The pressure-sensitive adhesive sheet according to claim 7 , wherein the design layer is a layer containing an acrylic resin.

10. The extensible film layer further includes a surface protective layer disposed on the opposite side of the second base layer to the pattern layer, The pressure-sensitive adhesive sheet according to claim 7 , wherein the surface protective layer is a layer containing a urethane resin or an acrylic resin.

11. The extensible film layer further includes a surface protective layer disposed on the opposite side of the second base layer to the pattern layer, The pressure-sensitive adhesive sheet according to claim 7 , wherein the surface protective layer is a layer containing an acrylic resin.

12. The pressure-sensitive adhesive sheet according to claim 1 , wherein the release sheet comprises a polyolefin resin film or a polyethylene terephthalate resin film.

13. The release sheet comprises a paper layer, a polypropylene film layer formed on the paper layer, and a release layer formed on the polypropylene film layer and containing a silicone resin; The pressure-sensitive adhesive sheet according to claim 1 , further comprising the printed resin film on the peelable layer.

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