Release liner and adhesive sheet

Abstract

[Problem] To provide: a release liner which suppresses a contact area of an adhesive layer to come into contact with an adherend during positioning, while enabling the adhesive layer to desirably exhibit adhesiveness after positioning; and an adhesive sheet. [Solution] A release liner 100 according to the present invention has a surface 101 that is provided with a plurality of recesses 120. Each recess is tapered toward a deepest part 121; and a portion 100 between recesses has a projected cross-sectional shape that protrudes in the thickness direction D1 of the release liner. The projected cross-sectional shape is tapered by continuously sloping from the deepest part of a recess toward a tip 111; and with respect to the projected cross-sectional shape, the height h thereof and a width w thereof at 1 / 2h, which is a half of the height h, satisfy the relational expression w > h.

Description

Technical Field

[0001] The present invention relates to a release liner and an adhesive sheet.

Background Art

[0002] Conventionally, in order to impart functions such as anti-bulging to an adhesive sheet, a fine embossed pattern has been formed on the surface of the adhesive layer. For example, Patent Document 1 discloses forming a plurality of minute protrusions on the surface of the adhesive layer, and Patent Document 2 discloses forming groove-shaped valleys in the adhesive layer.

[0003] The plurality of minute protrusions formed on the surface of the adhesive layer in the adhesive sheet of Patent Document 1 and the groove-shaped valleys formed in the adhesive layer in the adhesive sheet of Patent Document 2 disappear over time after the adhesive sheet is attached to the adherend, and a strong adhesive force to the adherend is exhibited due to an increase in the contact area between the adhesive layer and the adherend. In the example of Patent Document 1, it is disclosed that the minute protrusions of the adhesive layer disappeared one day after attachment.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, as in Patent Document 1 above, if it takes as long as about one day for a strong adhesive force to be exhibited, there is a risk that the adhesive sheet may be misaligned during that time. Therefore, in actual pasting work, it is preferable that a strong adhesive force is exhibited as soon as possible after the adhesive sheet is aligned at a predetermined position.

[0006] On the other hand, in the adhesive sheet of Patent Document 2, the width of the groove formed in the adhesive layer is suppressed, and the convex body that contacts the adherend in the adhesive layer is formed wide. Therefore, although it adheres to the adherend quickly, it is difficult to reattach and difficult to align.

[0007] Therefore, an object of the present invention is to provide a release liner and an adhesive sheet that can suppress the contact area of the adhesive layer with respect to the adherend during alignment and can suitably exhibit the adhesive force in the adhesive layer after alignment.

Means for Solving the Problems

[0008] The release liner of the present invention for achieving the above object has a surface on which a plurality of recesses are formed. The recesses narrow toward the deepest part, and the portion between the recesses has a convex cross-sectional shape in the thickness direction of the release liner. The convex cross-sectional shape continuously inclines and narrows from the deepest part to the tip of the recess. In the convex cross-sectional shape, the width w at a height of 1 / 2h, which is half of the height h, and the height h satisfy w > h. The plurality of recesses are formed dot-like on the surface, and the recesses said deepest part have a shape that curves while the inclination continuously changes. The tip of the convex cross-sectional shape has a shape that curves while the inclination continuously changes, and the deepest part of the concave portion and the tip of the convex cross-sectional shape have shapes that are inverted in the stacking direction.

[0009] The adhesive sheet of the present invention for achieving the above object has, in this order in the lamination direction, the release liner, an adhesive layer disposed on the surface of the release liner, and a base material layer.

Effects of the Invention

[0010] According to the invention having the above configuration, as a result of the shape of the release liner being inverted and transferred to the adhesive layer of the adhesive sheet, a plurality of convex portions that contact the adherend are formed, and a relatively wide gap is formed between the convex portions. Thereby, the ratio of the convex portions that contact the adherend is relatively suppressed. For this reason, the contact area of the adhesive layer with respect to the adherend can be suppressed during alignment.

[0011] Moreover, according to the invention having the above configuration, at the time of adhesion after alignment, since the adhesive layer conforms to the surface of the adherend and is likely to adhere closely, the adhesive force can be suitably exhibited in the adhesive layer.

Brief Description of the Drawings

[0012]

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Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. Note that the dimensional ratios in the drawings are exaggerated for the convenience of explanation and are different from the actual ratios.

[0014] As shown in FIG. 1, the release liner 100 of the embodiment has a surface 101 on which convex portions 110 and concave portions 120 are alternately formed. The plurality of convex portions 110 are scattered in an island shape on the surface 101. Also, the plurality of concave portions 120 are formed so as to be scattered on the surface 101. A release agent such as silicone may be applied to the surface 101.

[0015] The release liner 100 is formed of, for example, paper or a resin film, but is not particularly limited by what material it is formed of. Also, in the illustrated example, the release liner 100 has a single-layer structure, but may have a laminated structure in which a plurality of layers are laminated. Examples of the laminated structure include a laminated structure in which a coating layer formed of a thermoplastic resin such as polyethylene (PE) is laminated on the surface of a paper base material formed of, for example, high-quality paper, glassine paper, kraft paper, etc., or a resin layer formed of polyethylene terephthalate (PET), etc., but is not limited thereto.

[0016] As shown in FIG. 2, the concave portion 120 narrows toward the deepest part 121. The deepest part 121 preferably has a shape that curves while the inclination continuously changes, but is not limited thereto, and may be, for example, planar.

[0017] In the present embodiment, the portion between the concave portions 120 is a convex portion 110 protruding in the thickness direction D1 and has a convex cross-sectional shape. The convex cross-sectional shape continuously slopes and narrows from the deepest part 121 to the tip 111 of the concave portion 120. Also, in the convex cross-sectional shape, the height h (the distance between the deepest part 121 and the tip 111 in the thickness direction D1) and the width w at a height of 1 / 2h, which is half of the height h, satisfy w > h. The tip 111 of the convex portion 110 (the convex cross-sectional shape) has a shape that curves while the inclination continuously changes.

[0018] The height h of the convex cross-sectional shape is not particularly limited, but is, for example, about 4 μm to 50 μm, and preferably 5 μm or more and 15 μm or less. Also, the width w is preferably 15 μm or more and 400 μm or less, but is not limited thereto.

[0019] Further, the intervals between the convex portions 110 and the intervals between the concave portions 120 in the plane direction orthogonal to the thickness direction D1 are not particularly limited, but are each, for example, about 30 μm to 800 μm, preferably 50 μm or more and 500 μm or less.

[0020] The convex portions 110 and the concave portions 120 are formed, for example, by embossing, but how they are formed is not particularly limited. In embossing, for example, a roller or a mold having a shape in which the convex portions 110 and the concave portions 120 are inverted on its surface is pressed against a sheet-like liner material having a flat surface, whereby the convex portions 110 and the concave portions 120 are formed. The fine shape of the surface of the roller or the mold used for embossing is formed, for example, by etching, but is not limited thereto, and the fine shape may be formed on the surface of the roller or the mold by other methods.

[0021] As shown in FIG. 3, the release liner 100 is laminated in this order with the adhesive layer 20 and the base material layer 30, and together with them, constitutes the adhesive sheet 10.

[0022] The adhesive sheet 10 is used, for example, for advertisements and decorations to be attached to adherends such as automobiles, motorcycles, trains, trucks, outdoor signs, outdoor advertisements, show windows, walls, etc. However, the use may be other than advertisements and decorations, and what kind of adherend it is attached to is not particularly limited. Further, the shape of the adhesive sheet 10 is not particularly limited, and may be, for example, a rectangular shape such as a sheet of paper, a long shape, or a shape formed according to the shape of the adherend.

[0023] The adhesive sheet 10 is formed, for example, by applying an adhesive to the release liner 100 to form the adhesive layer 20, and then laminating the base material layer 30 to the adhesive layer 20 while pressing it with a roller or the like, but is not limited to such a manufacturing method.

[0024] The adhesive layer 20 is formed of, for example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a styrene block copolymer adhesive, etc., but is not particularly limited, and they may be used alone or in combination of two or more.

[0025] The base material layer 30 can be variously designed according to the use of the adhesive sheet 10. For example, when the adhesive sheet 10 is a decorative sheet to be attached to an adherend such as an automobile, the base material layer 30 has, for example, a laminated structure in which a support layer made of resin, a decorative layer including decorations such as colors and patterns, and a transparent protective layer are laminated in this order, but is not limited thereto. For example, a form composed of only a single resin layer is also included in the scope of the present invention. In addition, a form in which the constituent material of the base material layer 30 is a paper base material is also included in the scope of the present invention.

[0026] As shown in FIG. 4, the adhesive sheet 10 is used by peeling off the release liner 100 and is attached to the adherend via the adhesive layer 20.

[0027] The adhesive layer 20 has a shape in which the shape of the surface 101 of the release liner 100 is inverted and transferred by the arrangement on the surface 101 of the release liner 100, and has convex portions 21 obtained by inverting and transferring the concave portions 120 of the release liner 100 and concave portions 22 obtained by inverting and transferring the convex portions 110 of the release liner 100 alternately.

[0028] As shown in FIG. 5, the convex portions 21 and the concave portions 22 are formed on the entire surface of the adhesive layer 20. The plurality of convex portions 21 are scattered in an island shape. Since there are gaps between the convex portions 21, even if air intervenes between the adhesive layer 20 and the adherend, the air is discharged through the gaps between the convex portions 21, and the swelling of the adhesive sheet 10 is prevented.

[0029] Further, when the adhesive layer 20 is in a state of lightly contacting the adherend, it contacts the adherend at the tip of the convex portion 21, and contact with the adherend is suppressed at the concave portion 22. Therefore, the contact area between the adhesive layer 20 and the adherend is kept small, and the adhesive force of the adhesive layer 20 to the adherend is weak. Accordingly, when the adhesive layer 20 is in a state of lightly contacting the adherend, the adhesive sheet 10 has a slidable property (slidability).

[0030] Next, the effects of the present embodiment will be described.

[0031] As shown in FIG. 6, in the adhesive sheet 10A of Comparative Example 1 having the same configuration as the configuration disclosed in Patent Document 2 cited above, the width of the groove portion 22A formed in the adhesive layer 20A is suppressed, and thereby, in the adhesive layer 20A, the convex bodies 21A that contact the adherend 1 are formed wide. For this reason, the adhesive sheet 10A of Comparative Example 1 adheres to the adherend 1 promptly, and it is difficult to slide it to change the position or reattach it, and it is difficult to align it to a desired position.

[0032] On the other hand, according to the present embodiment as shown in FIG. 7, the shape of the release liner 100 is inverted and transferred to the adhesive layer 20, whereby the contact area of the adhesive layer 20 with respect to the adherend 1 can be suppressed.

[0033] Specifically, in the adhesive layer 20, convex portions 21 are formed by inverting and transferring the concave portions 120 of the release liner 100, and gaps 11 are formed between the convex portions 21. The gaps 11 correspond to the convex cross-sectional shape (convex portion 110) between the concave portions 120 of the release liner 100. In the present embodiment, since the convex cross-sectional shape is formed with a relatively wide width (width w > height h), correspondingly, the gaps 11 are also formed with a relatively wide width. As a result, the ratio of the convex portions 21 that contact the adherend 1 is relatively suppressed. Therefore, according to the present embodiment, the contact area of the adhesive layer 20 with respect to the adherend 1 can be suppressed, the adhesive sheet 10 can be easily slid to change the position or reattach it, and alignment is easy.

[0034] After alignment, the operator presses the adhesive sheet 10 to adhere it to the adherend 1. As the adhesive sheet 10 adheres to the adherend 1, the convex portions 21 and the gaps 11 disappear, and the adhesive layer 20 flattens and adheres closely to the adherend 1.

[0035] As shown in FIG. 8, in the adhesive sheet 10B of Comparative Example 2 having the same configuration as the configuration disclosed in Patent Document 1 cited above, since fine micro-protrusions 21B are formed on the adhesive layer 20B, the contact area between the adherend 1 and the adhesive layer 20B is suppressed during alignment. However, according to the surface shape of the adhesive layer 20B of Comparative Example 2, it is difficult for a strong adhesive force to be quickly exhibited after alignment.

[0036] Specifically, in the adhesive sheet 10B of Comparative Example 2, a plurality of recesses 22B, a flat surface 23B that extends widely away from the adherend 1, and a large number of minute protrusions 21 that are separated from each other and independent are formed in the adhesive layer 20B. Due to these, many gaps are formed between the adherend 1 and the adhesive layer 20B. Therefore, when adhering after alignment, it takes time for the adhesive layer 20B to conform to and adhere closely to the surface of the adherend 1, and it is difficult for a strong adhesive force to be exhibited.

[0037] On the other hand, in the present embodiment, a plurality of recesses 120 are formed in the release liner 100, and the convex cross-sectional shape of the portion (convex portion 110) between the recesses 120 continuously inclines and narrows from the deepest part 121 of the recess 120 to the tip 111. As a result of such a shape being inverted and transferred to the adhesive layer 20, as shown in FIG. 7, the adhesive layer 20 continuously inclines and narrows from the tip of the convex portion 21 to the portion 23 that is most separated from the adherend 1 following it. Therefore, in the present embodiment, a flat surface 23B that extends widely away from the adherend 1 and a large number of minute protrusions 21B that protrude independently on the flat surface 23B in the adhesive sheet 10B of Comparative Example 2 are not formed, and it is suppressed that many gaps are formed between the adherend 1 and the adhesive sheet 10B as in Comparative Example 2.

[0038] Therefore, according to the present embodiment, when adhering after alignment, the adhesive layer 20 easily conforms to and adheres closely to the surface of the adherend 1, and the adhesive force can be preferably exhibited.

[0039] Further, in the present embodiment, a plurality of concave portions 120 are formed at intervals on the surface 101 of the release liner 100. As a result of such a shape being inverted and transferred to the adhesive layer 20, as shown in FIG. 5, in the adhesive layer 20, a plurality of convex portions 21 are formed at intervals in an island shape. Thereby, when the adhesive layer 20 is in a state of gently contacting the adherend 1, the contact area with the adherend 1 is effectively suppressed, so that it becomes easier to slide and reposition the adhesive sheet 10, and the ease of alignment increases.

[0040] The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

[0041] For example, as shown in FIG. 9, a release liner 200 having a plurality of groove-shaped concave portions 220 is also included in the scope of the present invention.

[0042] The portions between the concave portions 220 form ridge portions 210 extending in a streak shape. The ridge portions 210 protrude in the thickness direction D1 and extend in the surface direction D2 orthogonal to the thickness direction D1 to reach the edge of the release liner 200.

[0043] The ridge portions 210 have the same cross-sectional shape as the convex portions 110 of the above-described embodiment shown in FIG. 2 in the surface direction D3 orthogonal to the surface direction D2. Further, the concave portions 220 have the same cross-sectional shape as the concave portions 120 of the above-described embodiment shown in FIG. 2 in the surface direction D3.

[0044] According to the release liner 200 of the modified example, the ridge portions 210 are inverted and transferred to the adhesive layer of the adhesive sheet, and as a result, streak-shaped grooves reaching the edge of the adhesive layer are formed in the adhesive layer. By means of these grooves, when the adhesive sheet is attached to the adherend, air intervening between the adherend and the adhesive layer can be smoothly discharged, so that swelling can be more effectively prevented.

[0045] In the release liner 200 of the modification, the protruding portions 210 and the recessed portions 220 extend linearly in the plane direction D2, but are not limited to such a form and may extend in a bent manner. Further, in addition to the protruding portions 210 and the recessed portions 220 extending in the plane direction D2, a release liner in which other protruding portions and recessed portions extending in the plane direction D3 are formed is also included in the scope of the present invention. In such a form, the protruding portions intersect with each other.

[0046] The convex portion 110 in the release liner 100 of the above embodiment and the protruding portion 210 in the release liner 200 of the above modification both have a configuration protruding in the thickness direction D1. However, the present invention is not limited to a form in which a portion between the recessed portions protrudes as in those cases.

[0047] For example, in the release liner 300 of another modification shown in FIG. 10, a plurality of recessed portions 320 are formed at intervals, and a portion 310 between the recessed portions 320 has a convex cross-sectional shape satisfying the relationship of width w > height h, similar to the above embodiment shown in FIG. 2, but does not protrude from the surface 301 of the release liner 300. In this form, the tip 311 in the convex cross-sectional shape forms, for example, the edge of the opening of the recessed portion 320.

[0048] This application is based on International Application No. PCT / JP2019 / 042875 filed on October 31, 2019, the disclosure of which is incorporated by reference in its entirety.

Explanation of Signs

[0049] 1 Adherend, 10 Adhesive sheet, 20 Adhesive layer, 21 Convex portion, 22 Recessed portion, 30 Base material layer, 10A, 10B Adhesive sheets of comparative examples, 20A, 20B Adhesive layers, 30A, 30B Base material layers, 100 Release liner, 101 Surface of the release liner, 110 Convex portion (the location between concave portions), 111 Tip of the convex portion (the tip of the convex cross-sectional shape), 120 Concave portion, 121 Deepest part, 200 Release liner, 210 Ridge portion (the location between concave portions), 220 Concave portion, 300 Release liner, 301 Surface of the release liner, 310 Location between concave portions, 320 Concave portion, D1 Thickness direction, D2, D3 Plane direction, h Height, w Width.

Claims

1. A release liner having a surface with a plurality of recesses formed therein, wherein the recesses narrow toward the deepest part, the portions between the recesses have a convex cross-sectional shape in the thickness direction of the release liner, the convex cross-sectional shape continuously inclines and narrows from the deepest part to the tip of the recess, in the convex cross-sectional shape, the width w at a height of 1 / 2h, which is half of the height h, and the height h satisfy w > h, the plurality of recesses are formed dot-like on the surface, the deepest part of the recess has a shape that curves while the inclination continuously changes, the tip of the convex cross-sectional shape has a shape that curves while the inclination continuously changes, a release liner, wherein the deepest part of the recess and the tip of the convex cross-sectional shape have shapes inverted in the stacking direction.

2. An adhesive sheet having, in this order in the stacking direction, the release liner according to Claim 1, an adhesive layer disposed on the surface of the release liner, and a base material layer.

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