JP2009001667A - Release sheet for forming recessed part in adhesive layer surface of adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a release sheet in which a linear protruded part is formed on the surface, the release sheet being attached to an attaching surface without involving foam and attached to the attaching surface after readily eliminating foam even when foam is involved, when releasing the release sheet and then attaching an adhesive to an adherend. <P>SOLUTION: The release sheet is used for forming a recessed part on the surface of the adhesive layer of the adhesive sheet. The release sheet includes: a release sheet substrate; a first continuous linear protruded part formed on the sheet substrate; and a second continuous linear protruded part, wherein the first continuous linear protruded part is mutually crossed with the second continuous linear protruded part. As a result, many lattices each composed of four sides having acute angle parts are formed on the longitudinal direction side of the release sheet. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a release sheet for forming a recess on the pressure-sensitive adhesive layer surface of a pressure-sensitive adhesive sheet, which is used to form a pressure-sensitive adhesive sheet that can be stuck to an adherend without involving air on the sticking surface.
Furthermore, it is related with the adhesive sheet obtained using this peeling sheet, and the method of forming a recessed part in the adhesive layer surface.

  The adhesive sheet is generally a method in which a pressure-sensitive adhesive is applied to a substrate and dried, and then a release sheet having a smooth surface is bonded, or conversely, the pressure-sensitive adhesive is applied to the release sheet and dried, and then transferred to the substrate. It is produced by a method such as

Since such an adhesive sheet has no air escape path when affixed to an adherend, it is easy to entrain air, that is, air bubbles are easily formed. It was necessary to eliminate the poor appearance.
Another method is to spray the surface of the pressure-sensitive adhesive layer with water or soapy water to weaken the adhesive strength, determine the approximate position by applying it to the adherend, and then apply water using a squeegee. There has also been a method of applying soap and soapy water by scraping it from the application surface.
However, these methods cause problems in durability because the base material is scratched with a needle or the like, and there is a problem that work is troublesome.

As one method for improving such a problem, an adhesive film in which air passages are formed by providing irregularities on the surface of the adhesive layer has been proposed in order to make it easier for air that has entered during sticking to escape.
For example, a pressure-sensitive adhesive film composed of a pressure-sensitive adhesive film main body and a release film has been proposed in which a narrow groove continuous with a predetermined pattern is provided on the pressure-sensitive adhesive surface side of the pressure-sensitive adhesive film main body (Patent Document 1).
However, since the narrow groove is formed by pressing embossing from the release film side in the adhesive film main body and the release film laminated to each other, when the release film is thick, only the release film is formed. However, the emboss formation does not reach the adhesive surface of the adhesive film body.

In addition, an adhesive layer is formed on the surface of the film-like support, and a concave groove having a depth of 30 μm or less is provided on the surface of the adhesive layer so as to be oblique to the length direction thereof. Has been proposed (Patent Document 2).
The concave groove is formed by applying an adhesive to one side of the substrate and pressing the adhesive layer surface with an engraving roller while drying. That is, the concave groove is formed when the adhesive is not completely dried. Therefore, there is a problem that the pressure-sensitive adhesive layer becomes insufficiently dried or the pressure-sensitive adhesive foams during pressing by the engraving roller. Even if the concave groove can be formed without any problem, when the adhesive sheet is bonded, there is also a problem that bubbles are difficult to escape in the direction perpendicular to the longitudinal direction of the concave groove or at a relatively large angle.

In order to deal with such problems, a method has been proposed in which an uneven shape is formed on the surface of the pressure-sensitive adhesive layer by embossing the surface of the release film and transferring it to the surface of the pressure-sensitive adhesive layer.
For example, in an adhesive sheet for wallpaper or the like, after a pressure-sensitive adhesive layer is provided on one surface of a substrate having a smooth surface, the surface of the release sheet having a large number of recesses is applied to the surface and further pressed. Thus, a method for forming a convex portion has been proposed (Patent Document 3).

  Moreover, in the easily peelable tack label laminated in the order of the substrate, the pressure-sensitive adhesive layer, and the release paper, the pressure-sensitive adhesive layer side of the release paper has a concave-convex surface, whereby the concave-convex surface is transferred to the pressure-sensitive adhesive layer, A method for forming a pressure-sensitive adhesive layer having an uneven surface has been proposed (Patent Document 4).

Furthermore, using a synthetic resin film embossed as a continuous convex line of 1 to 15 μm as a release film, the continuous convex line is transferred to the adhesive surface of the adhesive layer, thereby being continuous with the adhesive layer. An adhesive film in which a concave line is formed has been proposed (Patent Document 5).
JP-A-7-138541 Japanese Utility Model Publication No. 59-44750 Japanese Utility Model Publication No. 53-162156 Japanese Utility Model Publication No. 7-29569 JP 59-78285 A

  In the invention described in Patent Document 4, referring to FIG. 7 described therein, groove-shaped irregularities are provided only on the pressure-sensitive adhesive layer in an oblique direction, and air easily escapes in the groove forming direction. When pressing with a roller or the like perpendicular to the groove forming direction or with a relatively large angle, especially when pressing with a high-speed rotating roller, there is a problem that air is insufficiently released. ing.

Moreover, according to the Example as described in patent document 5, the adhesive agent is apply | coated on a peeling film and the adhesive film is produced. As an example of continuous convex lines, a straight line shape (FIG. 1), a wavy line shape (FIG. 2), and a lattice shape (FIG. 3) are shown. How are these embossed patterns in the length direction of the film? It is not shown whether it is formed in any direction.
If a release film in which a linear or wavy embossed pattern is formed at a right angle or a relatively large angle with respect to the length direction of the release film is used, the release film adheres to the embossed pattern forming surface of the release film. When applying the agent, it is easy to embrace bubbles.
On the other hand, when using a release film that has the same direction (parallel) or a relatively small angle with respect to the length direction of the release film and a linear embossed pattern is formed, it is difficult to entrap bubbles when applying adhesive. Further, it is difficult to entrap air bubbles when the base film is further bonded. However, when the pressure-sensitive adhesive sheet is used, bubbles formed on the pasting surface do not escape in the direction perpendicular to the formation direction of the linear embossed pattern.
In addition, even if a release film having an embossed pattern formed in a lattice shape as shown in FIG. 3 is used, if the angle of intersection with respect to the length direction of the release film is large where the convex lines intersect, There is a drawback that it is easy to enclose bubbles.

  As described above, many proposals have been made as a method of providing a concave groove on the surface of the pressure-sensitive adhesive layer so as not to entrain air bubbles when sticking the pressure-sensitive adhesive sheet. However, when applying a pressure-sensitive adhesive to a release film, etc. There have been problems such as entrainment or the presence of bubbles that are difficult to escape when sticking an adhesive sheet.

  The present invention has been made in view of the above problems, that is, when forming a groove for removing air bubbles on the pressure-sensitive adhesive surface, the release paper on which the convex portion is formed is pressed against the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet. Then, when forming the groove, in addition to the convex line oblique to the left and right with respect to the flow direction, it is difficult to embrace the bubbles by adding a convex line along the flow direction, and further when sticking to the adherend, The present invention relates to a release sheet having a convex portion on the surface for forming a pressure-sensitive adhesive layer surface that can be stuck without involving air bubbles on the sticking surface, and that can be easily removed even when air bubbles are involved.

In the release sheet having a convex portion on the surface, the present inventors set the arrangement direction and the arrangement interval of the continuous linear convex portions provided on the release sheet substrate to a predetermined one, thereby making the base of the adhesive sheet. The problem of air entrapment when the release sheet is pressure-bonded to the surface of the pressure-sensitive adhesive layer provided on the upper surface of the material is improved. Further, when the release sheet is pressure-bonded, the convex portion of the release sheet is formed on the pressure-sensitive adhesive layer surface. It has been found that the problem of air entrainment that occurs when the pressure-sensitive adhesive sheet is attached to the adherend surface can be solved by forming a pressure-sensitive adhesive layer having a recess on the surface.
That is, the present invention is a release sheet for forming a recess on the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive sheet, the release sheet comprising a release sheet base material and a first continuous sheet formed on the sheet base material. It comprises a linear convex portion and a second continuous linear convex portion, and the first continuous linear convex portion is larger than 0 ° obliquely to the right with respect to the length direction of the release sheet. A plurality of parallel protrusions having an angle of less than 15 ° are provided in parallel at an interval of 100 to 2000 μm, and the second continuous linear protrusion is on the left with respect to the length direction of the release sheet. The first continuous linear protrusion and the second continuous line are provided in parallel with an angle of greater than 0 ° and less than 15 ° at an interval of 100 to 2000 μm. The convex portions of the shape intersect with each other and consist of four sides having an acute angle portion on the longitudinal direction side of the release sheet. Characterized by comprising forming a number of lattice relates release sheet.

  Moreover, this invention is a peeling sheet for forming a recessed part in the adhesive layer surface of an adhesive sheet, Comprising: This peeling sheet was the 3rd continuous formed on the peeling sheet base material and this sheet base material. A linear convex portion, a fourth continuous linear convex portion, and a fifth continuous linear convex portion, wherein the third continuous linear convex portion is a length of the release sheet. A plurality of parallel convex portions having an angle of 10 to 45 ° diagonally to the right direction are provided in parallel at an interval of 100 to 2000 μm, and the fourth continuous linear convex portion is the release sheet. A plurality of parallel projections at an interval of 100 to 2000 μm with an angle of 10 to 45 ° obliquely to the left with respect to the length direction of With an angle of less than 10 ° diagonally left and right with respect to the length direction of the release sheet, at an interval of 100 to 2000 μm A plurality of lines in a row, the third continuous linear protrusion and the fourth continuous linear protrusion intersect each other, and further, the fifth continuous linear protrusion At least part of the portion passes through the intersection of the third continuous linear convex portion and the fourth continuous linear convex portion, and has three sides having an acute angle portion on the longitudinal direction side of the release sheet It is related with the peeling sheet characterized by forming many grating | lattices consisting of.

In the release sheet, it is desirable that a cross section of the first or second continuous linear protrusion has a substantially triangular and / or substantially quadrangular cross section.
At this time, when the cross section of the convex portion has a substantially triangular cross section, it is desirable that the length of the base of the convex portion is 5 to 100 μm and the height is 5 to 50 μm. When having a substantially rectangular cross section, it is desirable that the length of the bottom of the convex portion is 5 to 100 μm, the length of the upper side is greater than 0 and not more than 100 μm, and the height is 5 to 50 μm.

In the release sheet, it is desirable that any one of the cross sections of the third to fifth continuous linear protrusions has a substantially triangular and / or substantially rectangular cross section.
At this time, when the convex section has a substantially triangular cross section, the length of the base of the convex section is preferably 5 to 100 μm and the height is preferably 5 to 50 μm. When any of the cross sections has a substantially rectangular cross section, it is desirable that the length of the base of the convex portion is 5 to 100 μm, the length of the upper side is greater than 0 and not more than 100 μm, and the height is 5 to 50 μm.

Further, the first or second continuous linear convex portion has a linear shape and / or a wavy shape having periodicity when viewed from above the release sheet. Alternatively, at least a part of the second continuous linear convex portion has a period of 1000 μm as viewed from above the release sheet.
It is desirable to have a wavy line shape having a periodicity of m or more and an amplitude of 100 μm or less.

  The third to fifth continuous linear protrusions have a linear shape and / or a wavy shape having periodicity when viewed from above the release sheet. At least a part of the third to fifth continuous linear protrusions has a wavy line shape having a periodicity with a period of 1000 μm or more and an amplitude of 100 μm or less when viewed from above the release sheet. desirable.

Furthermore, the present invention provides the surface of the release sheet by press-bonding the release sheet according to any one of claims 1 to 12 to the surface of the pressure-sensitive adhesive layer formed on the pressure-sensitive adhesive sheet substrate. The present invention relates to a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which convex portions are transferred and continuous linear concave portions are formed.
Moreover, this invention makes the peeling sheet as described in any one of Claims 1 thru | or 12 press-fit to the surface of the adhesive layer formed on the adhesive sheet base material, and the said adhesive layer surface is the said The present invention also relates to a method for forming a continuous linear recess on the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive sheet by transferring the shape of the convex portion of the release sheet.

The release sheet of the present invention is a continuous linear recess having a predetermined shape by pressing a predetermined continuous linear convex portion formed on the substrate of the release sheet against the adhesive surface of the adhesive sheet. Can be easily formed (transferred) onto the pressure-sensitive adhesive surface.
Moreover, when the release sheet of the present invention presses the pressure-sensitive adhesive layer provided on the upper surface of the pressure-sensitive adhesive sheet substrate and the release sheet by a predetermined continuous linear convex portion formed on the base material of the release sheet. There is no air embracing at the interface, and even when air is embraced, the air can be easily pushed out by pressing.

  And the pressure-sensitive adhesive sheet of the present invention has a continuous linear recess formed on the pressure-sensitive adhesive layer transferred from the release sheet, and when the pressure-sensitive adhesive sheet is stuck to an adherend, air bubbles are not caught on the sticking surface. It is possible to stick, and even when bubbles are involved, the bubbles can be easily removed and pasted.

  Further, according to the method of forming a continuous linear recess on the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention, after the pressure-sensitive adhesive is applied and dried on the pressure-sensitive adhesive sheet substrate, the release sheet is pressed. Therefore, there is no problem such as foaming of the pressure-sensitive adhesive that occurs when the pressure-sensitive adhesive layer becomes undried or when a concave portion is directly formed in the pressure-sensitive adhesive layer using an embossing roller or the like.

  As described above, a method has been proposed in which an uneven shape is formed on the surface of the pressure-sensitive adhesive layer by embossing the surface of the release sheet and transferring it to the surface of the pressure-sensitive adhesive layer (Patent Document 3). To 5). However, even with these proposals, it is easy to embed air when applying a pressure-sensitive adhesive to the release sheet, so bubbles are formed when bonded to the pressure-sensitive adhesive sheet substrate, or when adhering to an adherend. There was a problem in that it was not fully satisfactory at the time of manufacture of the adhesive sheet and at the time of pasting of the adhesive sheet, such as insufficient air bubbles from the adhesive layer. .

In the present invention, first, as a method for producing a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer having a concave portion formed on the surface, a continuous linear convex portion is formed after applying and drying the pressure-sensitive adhesive on a pressure-sensitive adhesive sheet substrate. The method of pressing the released release sheet was selected.
Also, as the release sheet, a release sheet in which a plurality of continuous linear protrusions are arranged so as to intersect at a certain angle with respect to the length direction is examined, and the detailed conditions are examined. did.

First, a release sheet in which linear projections that are continuously arranged in a square lattice shape, which has been conventionally proposed, was studied.
At this time, as shown in FIG. 1, when linear protrusions are formed in a rhombic lattice shape with respect to the length direction of the release sheet and the angle (γ) in the length direction is an acute angle, the release sheet It has been found that when the sheet is pressed against the pressure-sensitive adhesive layer, it is difficult to entrap air, and the air entrainment can be suppressed even when the pressure-sensitive adhesive sheet is stuck. In addition, in FIG. 1, the up-down direction of a figure represents the length direction of a peeling sheet, and 1 and 2 show a linear convex part.
Furthermore, as a result of examining by changing the angle of γ shown in FIG. 1 in various ways, when a release sheet having an angle of γ of 30 ° or more is used, the release sheet is pressed against the adhesive layer using a pressing roll. It was found that the air embraced at the time of evacuation was difficult to escape, and in particular, bubbles were likely to remain at the points where the convex lines intersected in a lattice shape (point A). Of course, by softening the pressure-sensitive adhesive by heating at the time of pressing, it is possible to make it easier for bubbles to escape, but in this case, since the uneven shape imparted to the release sheet may be lost, the pressing temperature is sufficiently high. I can't do it.
If air bubbles remain, the product will be in a state where the adhesive layer on the substrate is in contact with the release layer. Over time, the air bubbles tend to gather at the center of the fine adhesive layer surrounded by micro grooves. A bubble mark is formed on the pressure-sensitive adhesive layer, and the bubble is removed at the time of sticking, but the appearance deteriorates due to the bubble mark.
On the other hand, when a release sheet having an angle γ of less than 30 ° is used, in detail, when γ is divided by a straight line parallel to the length direction in FIG. It has been found that when the angle is less than 15 °, air is not embraced when the pressure-sensitive adhesive layer is pressed, and air entrainment is suppressed even when the pressure-sensitive adhesive sheet is stuck.

Furthermore, the present inventors increase the passage of air formed by the linear protrusions that are continuous with the release sheet, that is, the continuous linear protrusions that are conventionally formed in a square lattice shape. The release sheet which divided | segmented and has a linear convex part which followed the triangular lattice form was created. At this time, a continuous linear convex portion having an isosceles triangular lattice shape with an acute base angle, a portion corresponding to the triangular base of the triangular lattice shape is inclined left and right with respect to the length direction of the release sheet. When arranged at an angle of less than 10 °, it was found that when the release sheet was pressed against the pressure-sensitive adhesive layer, it was difficult to entrap air, and air entrainment was suppressed even when the pressure-sensitive adhesive sheet was applied. .
Furthermore, as a result of studying various values of the base angle of the isosceles triangle, for example, as shown in FIG. 4 (and FIG. 5) which is an enlarged view of a part of the release sheet, continuous linear convex portions 3a, 4b, and 5a (FIG. 5: 3a ′, 4b ′, 5a ′) form a triangular lattice-shaped convex portion, and the continuous linear convex portion 3a at point C (FIG. 5: 3a ′) is continuous. When the linear convex part 5a (FIG. 5: 5a ′) or the continuous linear convex part 5a (FIG. 5: 5a ′) and the continuous linear convex part 4a (FIG. 5: 4a ′) intersect. When the formed angles (α ′, β ′) (FIG. 5: α ″, β ″) are 10 to 45 °, air is not embraced when pressed to the adhesive layer, It has been found that air entrainment is suppressed even when an adhesive sheet is applied.

  Hereinafter, the detail regarding the peeling sheet and adhesive sheet of this invention is demonstrated.

[Peeling sheet]
As a material for the release sheet used in the present invention, a film such as a PET (polyethylene terephthalate) film or an OPP (biaxially stretched polypropylene) film, a polyethylene laminated paper obtained by laminating polyethylene on paper, or the like can be used.
In addition, polyethylene such as PET film and OPP film can be laminated and embossed on the polyethylene part.

  The release sheet used in the present invention comprises a release sheet base material, a first continuous linear convex portion and a second continuous linear convex portion formed on the sheet base material, or And a release sheet base material, and a third continuous linear convex portion to a fifth continuous linear convex portion formed on the sheet base material.

The plurality of first and second, or third to fifth continuous linear protrusions provided on the release sheet used in the present invention have a constant angle with respect to the length direction, and have a constant interval. It is provided with a gap. Here, the “continuous linear convex portion” means that the convex portion may be substantially connected, for example, from one side of the outer periphery of the release sheet to another side, and a part thereof is divided in the middle. For example, it may be a broken line.
Although the above-mentioned continuous linear convex part is demonstrated in detail using FIGS. 2-14, the linear convex part shown in FIGS. 2-14 is an example, Comprising: The magnitude | size shown to a figure The shape is not limited at all.

  2-5 is the schematic diagram which expanded and showed a part when the peeling sheet of this invention was seen from upper direction. In any figure, the vertical direction of the figure indicates the length direction of the release sheet. In the figure, 1 (1a, 1b), 2 (2a, 2b), 3a (3a ′), 3b (3b ′), 4a (4a ′), 4b (4b ′), 5a (5a ′), 5b (5b ′), and 5c represent linear convex portions.

FIG.2 and FIG.3 shows the schematic diagram of the peeling sheet of the 1st form of this invention. When the release sheet is viewed from above, a plurality of continuous linear protrusions 1 and 2 form a square (diamond) lattice-like protrusion.
As shown in FIG. 3, on the release sheet, a plurality of pieces arranged with an angle (α, β) with respect to the length direction of the release sheet (lines parallel to the length direction are indicated by dotted lines). A continuous linear protrusion 1a (corresponding to a first continuous linear protrusion) and a continuous linear protrusion 2a (corresponding to a second continuous linear protrusion) intersect each other. Is provided.
At this time, the angles α and β are both greater than 0 ° and less than 15 °, and preferably α = β.
The interval d ₁ between the continuous linear convex portions 1a (or 2a) adjacent to the continuous linear convex portions 1b (or 2b) is 100 to 2000 μm, more preferably 200 to 600 μm.
It is.

In the release sheet of the first form, when the angles α and β exceed 15 ° (that is, when γ is 30 ° or more), at the intersection B between the continuous linear protrusions 1a and 2a, Air is easily entrapped when pressed against the pressure-sensitive adhesive, and air is also easily entrapped when a pressure-sensitive adhesive sheet formed by bonding the release sheet to the pressure-sensitive adhesive is applied.
Further, if the interval d ₁ between the continuous linear convex portions is less than 100 μm, the number of concave grooves formed by being transferred to the adhesive increases, and the adhesiveness is deteriorated. Can not be secured.

4 and 5 show schematic views of the release sheet according to the second embodiment of the present invention. When the release sheet shown in FIG. 4 is viewed from above, the triangular lattice-shaped convex portions are formed by the continuous linear convex portions, and in the release sheet shown in FIG. Are divided by linear convex portions parallel to each other to form triangular lattice-shaped convex portions and square (trapezoidal) lattice-shaped convex portions.
In the release sheet of the second embodiment of the present invention (FIG. 4), a plurality of continuous linear protrusions 3a, 3b (corresponding to a third continuous linear protrusion) and 4a, 4b (fourth). In addition to the continuous linear convex portions 3a and 4a, the continuous intersection C of the continuous linear convex portions 3a and 4a and the continuous intersection C 'of the continuous linear convex portions 3b and 4b are connected. A plurality of linear convex portions 5a and 5b (corresponding to a fifth continuous linear convex portion, passing through the intersection of the third and fourth continuous linear convex portions) are provided.
At this time, the angles α ′ and β ′ are both 10 to 45 °, and preferably α = β.
The distance d ₂ of the projecting portion 3b of the continuous linear convex portion 3a (or 4a) and adjacent continuous linear (or 4b) is 100 to 2000, more preferably 200~600μm
It is. The distance d ₃ between the convex portions 5a and 5b is 100 to 2000 μm, more preferably 200 to 600 μm.

In the release sheet (FIG. 5) according to another second embodiment of the present invention, a continuous linear convex portion that is parallel to the convex portion 5a ′ and does not pass through the intersection C ″, for example, a continuous linear shape. A plurality of continuous linear protrusions 5c positioned between the protrusions 5a ′ and 5b ′ (corresponding to the fifth continuous linear protrusions, the third and fourth continuous linear protrusions (If it does not pass through the intersection) is further provided. The interval d ₅ between the linear protrusions parallel to the length direction of the release sheet (for example, 5a ′ and 5c, 5c and 5b ′ in FIG. 5) is 100 to 2000 μm, more preferably 200 to 600 μm. .

In the release sheet according to the second aspect of the present invention, the fifth continuous linear convex portion only needs to pass at least a part of the intersection of the third and fourth continuous linear convex portions, and passes through the intersection. There may be no fifth continuous linear convex part, and the fifth continuous linear convex part passing through the intersection and the fifth continuous linear convex part not passing through the intersection. May be mixed.
In this case, the arrangement (arrangement) of the fifth continuous linear convex portion passing through the intersection and the fifth continuous linear convex portion not passing through the intersection is not particularly limited. For example, a fifth continuous linear protrusion that passes through the intersection point and a fifth continuous linear protrusion that does not pass through the intersection point may be arranged every other line. The arrangement may be such that one fifth continuous linear convex portion that does not pass through the intersection is arranged next to two continuous linear convex portions.

In the release sheet of FIG. 4 or FIG. 5, when the angle α ′, β ′ or α ″, β ″ exceeds 45 °, the release occurs at the intersections C and C ′ or C ″ and C ′ ″. Air is easily entrapped when the sheet is pressed against the pressure-sensitive adhesive, and air is also easily entrapped when a pressure-sensitive adhesive sheet formed by bonding the release sheet to the pressure-sensitive adhesive is applied. Further, when the angle α ′, β ′ or α ″, β ″ is 10 ° or less, the concave portion of the adhesive increases around the intersections C, C ′ or C ″ and C ′ ″. Not only is the adhesiveness worsened, but bubbles tend to accumulate.
In addition, when the interval d ₂ or d ₄ between the continuous linear convex portions is less than 100 μm, the number of concave grooves formed by being transferred to the adhesive increases, so that the adhesiveness deteriorates, and when it exceeds 2500 μm. It is not possible to secure a sufficient passage for bubbles.

The continuous linear protrusions 1a, 1b, 2a, 2b, 3a (3a ′), 3b (3b ′), 4a (4a ′), 4b (4b ′), 5a (5a ′), 5b (5b ′) ) And 5c, the cross section (transverse cross section) perpendicular to the longitudinal direction is triangular (FIG. 6 (a)), square (FIG. 6 (b)), trapezoid (FIG. c)), semi-circle (Fig. 6 (d)), or a combination of square and semi-circle (Fig. 6 (e)), dome shape other than semi-circle such as ellipse (Fig. 6 (f)) Among them, it is desirable to have a substantially triangular or substantially rectangular cross section.
In the cross-sectional shape of the cross section of the longitudinal direction of the peeling sheet 10 of this invention, the schematic diagram of a suitable example is shown in FIGS.

As shown in FIGS. 7 and 8, when the cross section of the convex portion 61 provided on the release sheet substrate 20 has a substantially triangular cross section, the length (wb) of the base 63 is 5 to 100 μm, more preferably 30 to 60 μm, and the height (h) of the apex 65 from the upper surface 62 of the release sheet substrate 2 is 5 to 50 μm, more preferably 10 to 20 μm. 7 and 8, d _w indicates the distance between the convex portion 61 (for example, corresponding to 1a in FIG. 3) and the adjacent convex portion 61 (for example, corresponding to 1b in FIG. 3), and is 100 to 2000 μm. More preferably 200 to 600 μm (in the case of FIGS. 7 and 8, for example, the interval between the vertex 65 of the convex portion 61 and the vertex 65 of the convex portion 61 located adjacent thereto corresponds to d _w . To do). In a single release sheet, the value of d _w may vary within the above numerical range.
The shape of the triangle may be an isosceles triangle (FIG. 7) or an unequal triangle (FIG. 8), and the shape of the triangle may be different for each continuous linear protrusion, and one continuous The shape of the triangle may change (for example, increase / decrease in the base, increase / decrease in the height, movement of the base, etc.) in the linear convex portion. In the perspective view of a continuous linear convex part, the case where there is an increase or decrease in the height of the convex part (FIG. 13) and the case where there is an increase or decrease in the base of the convex part (FIG. 14) are shown.
Furthermore, as shown in FIG. 8, the concave portions 64 between the plurality of continuous linear convex portions may not overlap with the upper surface 62 of the release sheet substrate 2. In this case, the length wb of the base 63 of the triangle corresponds to the length between the extended line of the oblique sides 66 and 67 and the intersection of the upper surface of the release sheet substrate.

As shown in FIGS. 9 to 11, when the cross section of the convex portion 81 has a substantially rectangular cross section, the length (wb) of the base 84 is 5 to 100 μm, more preferably 30 to 60 μm, and the length of the upper side 83 ( wt) is greater than 0 and not greater than 100 μm, more preferably greater than 0 and not greater than 20 μm, and the height (h) from the upper surface 82 of the release sheet substrate 2 is 5 to 50 μm, more preferably 10 to 20 μm. Preferably, wb> wt. 9 and 11, d _w represents the interval between the convex portion 81 (for example, corresponding to 1a in FIG. 3) and the adjacent convex portion 81 (for example, corresponding to 1b in FIG. 3), as described above. 9 to 2000 μm, and more preferably 200 to 600 μm (in the case of FIG. 9 and FIG. 11, for example, the above-described middle point 88 of the upper side 83 of the convex portion 81 and the upper side 83 of the convex portion 81 located adjacent thereto. The interval between the midpoints 88 corresponds to d _w ).
In a single release sheet, the value of d _w may vary within the above numerical range.

As shown in FIGS. 9 to 11, when the cross section of the convex portion 81 has a substantially rectangular cross section, the cross-sectional shape is a trapezoid (FIG. 9) as an example, but for example, as shown in FIG. Or the angle (δ, ε) formed by the base 84 and the hypotenuse 85 or 86 may be different, or the shape of the quadrangle may be different for each continuous linear protrusion. Furthermore, the quadrangular shape may change (for example, increase / decrease in the base, increase / decrease in the top, increase / decrease in the height, horizontal movement of the bottom, etc.) in one continuous linear convex portion.
Furthermore, as shown in FIG. 11, the recessed part 87 between the several continuous linear convex part does not need to overlap with the upper surface 82 of the peeling sheet base material 2. FIG. In this case, the length wb of the bottom side 84 of the quadrangle corresponds to the length between the extended line of the hypotenuses 85 and 86 and the intersection of the upper surface of the release sheet substrate.

Moreover, as shown in FIG.7 and FIG.8, the continuous linear convex part 61 whose cross section has a substantially triangular cross section, and as shown in FIGS. 9-11, a cross section has a substantially square cross section. The continuous linear convex part 81 may be mixed in one release sheet.
In addition, when the linear convex part 61 with a substantially triangular cross section and the continuous linear convex part 81 with a substantially rectangular cross section shown in FIGS. 9 to 11 are adjacent to each other, for example, the vertex 65 of the convex part 61 is used. When the midpoint 88 of the protrusion 81 may be a distance d _w of the linear convex portion.

  In the cross-sectional shape, in any of the above-described approximately triangular and approximately quadrangular shapes, if the length (wb) of the base (63 or 84) is less than 5 μm, a bubble passage cannot be secured, and if it is 100 μm or more, the groove is large. If it becomes too much, the adhesive surface becomes small, and the adhesiveness becomes worse. Further, if the height h is less than 5 μm, the passage of bubbles cannot be secured, and if it exceeds 50 μm, not only does the thickness of the pressure-sensitive adhesive layer become excessively thin, but also large when pressed against the pressure-sensitive adhesive layer. Pressure is required.

The continuous linear convex part seen from the upper side of the said peeling sheet may have a wavy-form external appearance which has linear form or periodicity. For example, the 1st and 2nd continuous linear convex part provided in the peeling sheet of the 1st form of this invention, or the 3rd thru | or 5th continuous provided in the peeling sheet of the 2nd form. Each of the linear convex portions may have a linear or wavy appearance when viewed from above, or may have a different appearance (straight or wavy). .
The wavy line shape having periodicity may be various, such as a triangular wave, a sine wave, or a combination of semicircles.
In addition, as shown in FIG. 12, the wavy shape may be different for each continuous linear convex portion, and the wavy shape changes (for example, the amplitude of one continuous linear convex portion). Increase / decrease, increase / decrease of period, etc.).
In addition, when the appearance of the continuous linear protrusions viewed from above the release sheet is a wavy line having periodicity, the interval d ₁ between the protrusions is, for example, a wavy line having periodicity as shown in FIG. The interval between the center line of the convex part (for example, the x-axis when a periodic function is assumed) and the center line of the adjacent wavy convex part having periodicity is indicated.

  When the continuous linear protrusions when the release sheet of the present invention is viewed from above has a wavy line appearance having periodicity such as a sinusoidal line shape or a triangular wave line shape, the period length is 1000 μm or more. It is desirable that the wave shape has an amplitude of 100 μm or less. Even if the period length is less than 1000 μm, the bubbles are difficult to escape even if the amplitude exceeds 100 μm.

The provision of the concavo-convex portion on the release sheet is achieved by passing the release sheet between the embossing roll engraved under the predetermined condition described above and the pressure roll under the predetermined condition.
Note that the release treatment of the release sheet can be performed before or after the embossing treatment, and the release treatment does not have to be performed.

[Adhesive sheet]
Various substrates such as PET film, OPP film, paper, Japanese paper, cloth, non-woven fabric, and composite substrates thereof can be used as the substrate used for the pressure-sensitive adhesive sheet.
Various adhesives such as rubber-based, acrylic-based, and silicon-based adhesives can be used, and any of a crosslinked type and a non-crosslinked type can be used.
The pressure-sensitive adhesive sheet is formed by applying a pressure-sensitive adhesive to the substrate and drying it.

[Method of forming recess in adhesive layer]
The pressure-sensitive adhesive sheet on which the above-mentioned pressure-sensitive adhesive layer is formed and the release sheet on which continuous linear convex portions are formed are bonded to the surface of the pressure-sensitive adhesive layer and the surface of the release sheet on which convex portions are formed, and the gap is adjusted. The two crimping rolls can be passed through and crimped.
At this time, by heating to such an extent that the continuous linear protrusions formed on the release sheet are not crushed, the pressure-sensitive adhesive is softened and bubbles are easily removed. For example, when a release sheet in which convex portions are formed on polyethylene is used, it is desirable to perform pressure bonding while heating at a temperature of 60 ° C to 80 ° C.

[Consideration of mechanism of effect generation]
What principle and action are the effects of “preventing air entrainment during manufacture of an adhesive sheet” and “adhesive sheet can be applied to an adherend without involving air on the application surface” produced by the present invention? Is not clear, but it is presumed to be due to the following actions.
The pressure-sensitive adhesive sheet (with a release sheet) of the present invention is formed by pressing the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet and the convex portion forming surface of the release sheet in the length direction of the pressure-sensitive adhesive sheet (or release sheet). At this time, it is considered that the entrapment of bubbles at the interface between the pressure-sensitive adhesive layer and the release sheet can be reduced by reducing the resistance caused by the convex portions generated when the pressure-sensitive adhesive layer is bonded.
Accordingly, either a large number of four-sided grids having an acute angle part on the longitudinal direction side of the release sheet (first release liner) or a large number of three-sided grids having an acute angle part on the longitudinal side is formed. It is considered that the resistance can be reduced by (release liner of the second form), and this is thought to lead to a reduction in entrapment of bubbles when forming the adhesive sheet.

And the recessed part of the adhesive layer formed by transferring the convex part formed in the peeling sheet is extended in the adhesive layer from the adhesive layer surface. The recess (groove) reaches the outer periphery of the adhesive layer or is provided on the adhesive layer and communicates with other recesses reaching the outer periphery of the adhesive layer, so that the adhesive sheet is attached to the adherend. When affixing, bubbles existing at the interface between the pressure-sensitive adhesive layer and the adherend surface can flow out from the concave portion to the outer periphery of the pressure-sensitive adhesive sheet.
At this time, by forming a large number of four-sided grids having acute-angled portions on the longitudinal direction side of the pressure-sensitive adhesive sheet (the release liner of the first form), the outflow of bubbles proceeds smoothly simultaneously with the application of the pressure-sensitive adhesive sheet, and the entrainment of bubbles Can be reduced. Further, it is considered that increasing the flow path (direction) of bubbles (second-type release liner) also helps to quickly discharge the remaining bubbles and consequently reduces the entrainment of bubbles.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these Examples.

[Production of adhesive sheet with release sheet]
A polyethylene terephthalate (PET # 50) film was adopted as the substrate of the release sheet, and polyethylene was melted and applied to a thickness of 25 μm. After performing a peeling treatment on the polyethylene surface of the obtained film, the sheet is heated to 100 ° C. immediately before being pressed with an embossing roll, and is pressed through an embossing roll that can form an embossing pattern having a predetermined shape described later, A release film having an embossed surface was prepared.
A polyethylene terephthalate (PET # 125) film was used as the base material of the pressure-sensitive adhesive sheet, and a rubber-based pressure-sensitive adhesive was applied at a thickness of 25 μm after drying to produce a pressure-sensitive adhesive sheet.
The release sheet having the embossed surface and the pressure-sensitive adhesive sheet were bonded together through a pressure roll to obtain a pressure-sensitive adhesive sheet with a release sheet.

[Evaluation]
The adhesive sheet with a release sheet was prepared, and after 5 days, the presence or absence of air bubbles present on the adhesive surfaces of the two sheets bonded together was magnified 150 times with a video microscope and observed (Evaluation 1).
Further, the shape (state) of the concave portion on the surface of the pressure-sensitive adhesive layer after the release sheet was peeled off from the pressure-sensitive adhesive sheet was similarly observed with a video microscope at 150 times (Evaluation 2).
Furthermore, after peeling off the release sheet, the adhesiveness of the adhesive sheet to the acrylic plate and the presence or absence of bubbles on the attachment surface were confirmed sensorially or macroscopically (Evaluation 3).

[Embossed pattern of release sheet]
Example 1.
As shown in FIG. 7, linear convex portions having a substantially isosceles triangle with a base length (wb) of 25 μm and a height (h) of 20 μm as shown in FIG. 7 are formed in a square lattice shape shown in FIGS. 2 and 3. .
The angle of the straight protrusions with respect to the length direction is about 6 ° (that is, α, β is 6 °, and γ is 12 ° in FIG. 3), and the arrangement interval (d ₁ ) of the straight protrusions is 300 μm. It was.

Example 2
The cross-sectional shape of the convex portion was the same as in Example 1, and the linear convex portion was formed as shown in FIG.
The angles with respect to the length direction of the linear protrusions (namely, α ′ and β ′ in FIG. 4) were 30 °, and the arrangement interval (d ₂ ) was 600 μm. Furthermore, the linear protrusions parallel to the longitudinal direction, the arrangement interval (d ₃₎ in 300 [mu] m, were also placed so as to pass through the intersection of the linear convex portion formed in the left and right diagonal directions.

Example 3 FIG.
The cross-sectional shape of the convex portions was the same as that in Example 1, and the linear convex portions were formed in the triangular lattice shape shown in FIG.
The angles of the linear protrusions with respect to the length direction (that is, α ″ and β ″ in FIG. 5) were 30 °, and the arrangement interval (d ₄ ) was 1200 μm. Furthermore, linear convex portions parallel to the length direction were arranged at an arrangement interval (d ₅ ) of 300 μm and passing through the intersections of the linear convex portions formed in the above-described diagonal directions. (Note that, as shown in FIG. 5, the straight convex portion parallel to the length direction that does not pass through the intersection point passes through the intermediate point of the intersection point of the linear convex portion formed in the oblique direction).

Comparative Example 1
The cross-sectional shape of the convex portions was the same as in Example 1, and only linear convex portions parallel to the length direction were produced at an arrangement interval of 300 μm.
Comparative Example 2
The cross-sectional shape of the protrusions was the same as in Example 1, and linear protrusions parallel to the length direction and linear protrusions in the direction perpendicular to the length direction were formed. At this time, the arrangement interval of the projections parallel to the length direction was 300 μm, and the arrangement interval of the projections in the orthogonal direction was 1200 μm.
Comparative Example 3
The cross-sectional shape of the convex portions was the same as in Example 1, and the linear convex portions were formed in a square lattice shape as shown in FIG. At this time, α and β were 30 ° (that is, γ was 60 °), and the arrangement interval (d ₁ ) of the linear protrusions was 300 μm.
Comparative Example 4
The cross-sectional shape of the convex portions was the same as in Example 1, and the linear convex portions were formed in a square lattice shape as shown in FIG. At this time, α and β were set to 22.5 ° (that is, γ was 45 °), and the arrangement interval (d ₁ ) of the linear protrusions was set to 300 μm.
Comparative Example 5
The cross-sectional shape of the convex portions was the same as in Example 1, and the linear convex portions were formed in a square lattice shape as shown in FIG. At this time, α and β were set to 15 ° (that is, γ was 30 °), and the arrangement interval (d ₁ ) of the linear protrusions was set to 300 μm.
Comparative Example 6
The cross-sectional shape of the convex portions was the same as in Example 1, and the linear convex portions were formed in a square lattice shape as shown in FIG. At this time, α and β were 6 ° (that is, γ was 12 °), and the arrangement interval (d ₁ ) of the linear protrusions was 80 μm.
Comparative Example 7
The cross-sectional shape of the convex portions was the same as in Example 1, and the linear convex portions were formed in a square lattice shape as shown in FIG. At this time, α and β were 6 ° (that is, γ was 12 °), and the arrangement interval (d ₁ ) of the linear protrusions was 2500 μm.
Comparative Example 8
The cross-sectional shape of the convex portions was the same as that in Example 1, and the linear convex portions were formed in a triangular lattice shape as shown in FIG. At this time, α ′ and β ′ were 60 °, d ₂ was 600 μm, and d ₃ was 300 μm.

[Test results]

As shown in Table 1, in the release sheets having the embossed patterns of Examples 1 to 3, no air bubbles are formed on the adhesive surface after being bonded to the adhesive sheet, and the adhesive layer is also removed after the release sheet is peeled off. The surface shape was also good with no traces of bubbles.
Furthermore, it was able to be applied with a good external shape without involving bubbles even when being applied to the acrylic plate.

On the other hand, in Comparative Example 1 in which only the linear protrusions parallel to the length direction of the release sheet were formed, there was no entrainment of bubbles on the adhesive surface when bonded to the adhesive sheet. Sometimes entrainment of bubbles occurred. In Comparative Example 2 in which linear protrusions were formed in the length direction of the release sheet and in a direction orthogonal thereto, bubbles were not involved when sticking to the acrylic plate, and had a good appearance. When pasting, bubbles were involved in the adhesive surface.
Moreover, although the convex part was formed in square lattice shape, the angle with respect to the length direction of a peeling sheet exceeds the range prescribed | regulated by this invention (Comparative Examples 3-5), and the arrangement space | interval of a linear convex part prescribes | regulates. Those that are out of the range (Comparative Examples 6 and 7), and those having convex portions formed in a triangular lattice shape, but the angle with respect to the length direction of the release sheet exceeds the range defined in the present invention (Comparative Example 8) It was not possible to obtain a result satisfying all of the absence of bubbles when bonded to the adhesive sheet, the shape of the pressure-sensitive adhesive layer surface after peeling the release sheet, and the absence of bubbles when applied to the acrylic plate .

FIG. 1 is an enlarged view of a part of the release sheet as viewed from above. FIG. 2 shows a schematic view when the release sheet of the first embodiment of the present invention is viewed from above. FIG. 3 shows a schematic view when the release sheet of the first embodiment of the present invention is viewed from above. FIG. 4 shows a schematic diagram when the release sheet of the second embodiment of the present invention is viewed from above. FIG. 5 shows a schematic diagram when the release sheet of the second embodiment of the present invention is viewed from above. FIG. 6 is a diagram showing various shapes of cross sections orthogonal to the longitudinal direction of the release sheet of continuous linear protrusions. FIG. 7 is a view showing a cross section (substantially triangular) of the continuous linear protrusions orthogonal to the longitudinal direction of the release sheet. FIG. 8 is a view showing a cross section (substantially triangular) of the continuous linear protrusions orthogonal to the longitudinal direction of the release sheet. FIG. 9 is a view showing a cross section (substantially a quadrangle) of continuous linear protrusions orthogonal to the longitudinal direction of the release sheet. FIG. 10 is a view showing a cross section (substantially square) of the continuous linear protrusions orthogonal to the longitudinal direction of the release sheet. FIG. 11 is a view showing a cross section (substantially square) of the continuous linear protrusions orthogonal to the longitudinal direction of the release sheet. FIG. 12 is a diagram showing a schematic view of the release sheet of the present invention as viewed from above. FIG. 13 is a perspective view of a continuous linear protrusion having a substantially triangular cross section. FIG. 14 is a diagram showing a perspective view of a continuous linear convex portion having a substantially triangular cross section.

Explanation of symbols

1 (1a, 1b), 2 (2a, 2b), 3a (3a ′), 3b (3b ′), 4a (4a ′), 4b (4b ′), 5a (5a ′), 5b (5b ′), 5c ... linear convex part 10 ... release sheet 20 ... release sheet substrate 61 ... convex part 62 having a substantially triangular cross-section ... upper surface 63 of the release sheet substrate ... Triangular base 64 ... Concave portion 65 between a plurality of linear convex parts ... Abbreviated triangular vertex 66 ... Abnormal triangular hypotenuse 67 ... Abnormal triangular hypotenuse 81 ... Substantially rectangular cross section Convex part 82 ... Upper surface 83 of release sheet substrate ... Upper side 84 of substantially quadrilateral ... Basic side 85 of substantially quadrilateral ... Oblique side 86 of substantially square ... Concave portion 88 between the plurality of linear convex portions ... Midpoint of the upper side of the substantially rectangular convex portion

Claims (14)

A release sheet for forming a recess on the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive sheet,
The release sheet comprises a release sheet base material, a first continuous linear convex portion and a second continuous linear convex portion formed on the sheet base material,
The first continuous linear convex portions have an angle of more than 0 ° and less than 15 ° obliquely to the length direction of the release sheet, and a plurality of parallel projections are spaced in parallel at an interval of 100 to 2000 μm. Provided,
The second continuous linear convex portions have an angle of more than 0 ° and less than 15 ° to the left with respect to the length direction of the release sheet, and a plurality of parallel projections in parallel at an interval of 100 to 2000 μm. Provided,
The first continuous linear convex portion and the second continuous linear convex portion intersect with each other to form a large number of lattices having four sides having an acute angle portion on the longitudinal direction side of the release sheet. A release sheet characterized by comprising: A release sheet for forming a recess on the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive sheet,
The release sheet includes a release sheet base material, a third continuous linear convex portion, a fourth continuous linear convex portion, and a fifth continuous linear shape formed on the sheet base material. With convex parts,
A plurality of the third continuous linear protrusions are provided in parallel at an interval of 100 to 2000 μm with an angle of 10 to 45 ° to the right with respect to the length direction of the release sheet. And
The fourth continuous linear protrusions are provided in parallel with an angle of 10 to 45 ° to the left with respect to the length direction of the release sheet and at an interval of 100 to 2000 μm. And
A plurality of the fifth continuous linear convex portions are provided in parallel at an interval of 100 to 2000 μm with an angle of less than 10 ° diagonally to the length direction of the release sheet. ,
The third continuous linear convex portion and the fourth continuous linear convex portion intersect each other, and at least a part of the fifth continuous linear convex portion is the first continuous linear convex portion. A large number of three-sided grids having an acute angle portion on the longitudinal direction side of the release sheet are formed through the intersection of three continuous linear convex portions and the fourth continuous linear convex portion. A release sheet characterized by that. The release sheet according to claim 1, wherein the first or second continuous linear convex portion has a substantially triangular and / or substantially rectangular cross section. When the cross section of the first or second continuous linear convex portion has a substantially triangular cross section, the base has a length of 5 to 100 µm and a height of 5 to 50 µm. 3. A release sheet according to 3. When the cross section of the first or second continuous linear convex portion has a substantially rectangular cross section, the length of the bottom side of the convex portion is 5 to 100 μm, the length of the upper side is greater than 0 and 100 μm or less, The release sheet according to claim 3, wherein the height is 5 to 50 µm. The release sheet according to claim 2, wherein any one of the cross sections of the third to fifth continuous linear protrusions has a substantially triangular and / or substantially rectangular cross section. When any of the cross sections of the third to fifth continuous linear convex portions has a substantially triangular cross section, the length of the base of the convex portion is 5 to 100 μm and the height is 5 to 50 μm. The release sheet according to claim 6. When any of the cross sections of the third to fifth continuous linear convex portions has a substantially quadrangular cross section, the length of the base of the convex portion is 5 to 100 μm and the length of the upper side is greater than zero. The release sheet according to claim 6, which is 100 µm or less and has a height of 5 to 50 µm. The first or second continuous linear convex portion has a linear shape and / or a wavy shape having periodicity when viewed from above the release sheet. The release sheet according to any one of claims 5 to 5. At least a part of the first or second continuous linear convex portion has a wavy shape having a periodicity with a period of 1000 μm or more and an amplitude of 100 μm or less when viewed from above the release sheet. The release sheet according to claim 9. The third to fifth continuous linear convex portions have a linear shape and / or a wavy shape having periodicity when viewed from above the release sheet. The peeling sheet as described in any one of thru | or 8 thru | or 8. At least a part of the third to fifth continuous linear convex portions has a wavy shape having a periodicity of a period of 1000 μm or more and an amplitude of 100 μm or less when viewed from above the release sheet. The release sheet according to claim 11. The convex part of this release sheet surface is transcribe | transferred by crimping | bonding the release sheet as described in any one of Claims 1 thru | or 12 to the surface of the adhesive layer formed on the adhesive sheet base material. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which continuous linear recesses are formed. The release sheet according to any one of claims 1 to 12 is pressure-bonded to the surface of the pressure-sensitive adhesive layer formed on the pressure-sensitive adhesive sheet substrate, and the convex shape of the release sheet is formed on the surface of the pressure-sensitive adhesive layer. A method of forming a continuous linear recess on the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive sheet.

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