Fixing sheet

Abstract

To provide a fixing sheet that inhibits occurrence of tunneling and has excellent air release property and water resistance.SOLUTION: A fixing sheet 1 includes: a double-sided tape 20 including adhesive layers 21 and 23 on respective sides of a support substrate 22 composed of PET; and release liners 10 and 30 that are disposed on respective sides in a lamination direction of the both-sided tape and respectively include embossed parts 11 and 31. The embossed parts are formed in a lattice shape as viewed from the lamination direction. The support substrate has a thickness of less than 50 μm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stationary sheet. [Background technology]

[0002] Conventionally, a method for fixing a flexographic plate used in flexographic printing to a printing drum has been known in which the flexographic plate is fixed to the printing drum via a double-sided tape having adhesive layers on both sides of a supporting substrate (for example, Patent Document 1 listed below).

[0003] Before the flexographic plate is fixed to the printing drum, the release liner is peeled off from one side of the double-sided tape and the flexographic plate is adhered to the exposed adhesive layer, allowing the flexographic plate / double-sided tape / release liner laminate to be stored. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-268291 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, laminates are stored in rolls with a diameter of approximately 30 mm. In this case, tunnel-like lifting, known as tunneling, can occur at the interfaces between the double-sided tape and the flexographic plate, and between the double-sided tape and the release liner.

[0006] Furthermore, when adhering the flexographic plate to the adhesive layer, the entrained gas may form gas pockets that deform the flexographic plate, resulting in printing defects such as uneven printing, blurring, and bleeding. Therefore, the adhesive layer must be able to release air.

[0007] The present invention has been made to solve the above problems, and has an object to provide a fixing sheet that suppresses the occurrence of tunneling and has air-releasing properties. [Means for solving the problem]

[0008] The above object of the present invention can be achieved by the following means.

[0009] (1) a double-sided tape having pressure-sensitive adhesive layers on both sides of a support substrate made of PET; release liners disposed on both sides of the double-sided tape in the lamination direction and having embossed portions; The embossed portion is formed in a lattice shape when viewed from the stacking direction, The thickness of the support substrate is less than 50 μm.

[0010] (2) The fixing sheet according to (1), wherein the embossed portion is configured to become thinner toward the support substrate in the stacking direction in a cross-sectional view.

[0011] (3) The fixing sheet according to (1) or (2), wherein the supporting substrate has a thickness smaller than that of the adhesive layer.

[0012] (4) The cross-sectional area of ​​the embossed portion is 2500 μm 2 The fixing sheet according to any one of (1) to (3), wherein the thickness is less than 1 / 2 mm. [Effects of the Invention]

[0013] According to the above-described fixing sheet, it is possible to provide a fixing sheet that suppresses the occurrence of tunneling, and that has air-releasing properties and water resistance. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing a fixing sheet according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view showing a release liner of the fixing sheet according to the present embodiment. [Figure 3] FIG. 10 is a schematic diagram of a rolled laminate obtained by peeling off the second release liner of the fixing sheet according to the present embodiment and attaching a flexographic plate to the second adhesive layer. [Figure 4] FIG. 10 is an SEM image showing a release liner of a fixing sheet according to a modified example. [Figure 5] 10 is a schematic diagram showing an embossed portion of a release liner of a fixing sheet according to a modified example. FIG. [Figure 6] 10 is a schematic diagram showing an embossed portion of a release liner of a fixing sheet according to a modified example. FIG. [Figure 7] FIG. 1 is an SEM image showing an embossed portion of a release liner of a fixing sheet according to Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0016] The configuration of the fixing sheet 1 according to this embodiment will be described below with reference to Figures 1 and 2. Figure 1 is a schematic cross-sectional view showing the fixing sheet 1 according to an embodiment of the present invention. Figure 2 is a plan view showing the release liners 10, 30 of the fixing sheet 1 according to this embodiment.

[0017] As shown in FIG. 1, the fixing sheet 1 according to this embodiment has, from above in the stacking direction, a first release liner 10, a double-sided tape 20, and a second release liner 30.

[0018] First release liner 10 is releasably disposed on the surface of first pressure-sensitive adhesive layer 21 of double-sided tape 20. First release liner 10 may have a configuration in which a thermoplastic resin such as polyethylene is laminated to a paper substrate such as kraft paper, fine paper, glassine paper, or coated paper, and a release agent layer made of a release agent such as silicone is further provided, but is not limited to such a configuration. The thickness (total thickness) of first release liner 10 is, for example, 50 to 200 μm, but is not limited to this.

[0019] First release liner 10 has embossed portion 11 with an embossed shape on the surface adjacent to first pressure-sensitive adhesive layer 21 .

[0020] Embossed portion 11 is composed of a plurality of ridges extending linearly along the surface of first release liner 10. The height of the embossed portion 11 is, for example, 5 to 20 μm, but is not limited to this.

[0021] The embossed portion 11 has a cross-sectional shape, such as a triangle, rectangle, trapezoid, a polygon with rounded vertices, or a substantially semicircular shape, in a cross section perpendicular to the direction extending along the surface of the first release liner 10. However, the cross-sectional shape in the cross section is not limited to these and can be designed as appropriate. The cross-sectional area of ​​the embossed portion 11 is, for example, 2500 μm 2 It is preferable that the cross-sectional area of ​​the embossed portion 11 is less than 2500 μm. This configuration can improve water resistance. If the cross-sectional area of ​​the embossed portion 11 is too large, there is a high possibility that water will penetrate through the embossed portion 11 during cleaning. The threshold value of the cross-sectional area of ​​the embossed portion 11 is 2500 μm. 2 Not limited to.

[0022] It is preferable that the embossed portion 11 is configured so that it tapers toward the support substrate 22 of the double-sided tape 20 in the stacking direction in a cross section perpendicular to the direction extending along the surface of the first release liner 10. This configuration improves the wettability of the transferred pressure-sensitive adhesive layer 21, improving water resistance, and also increases the adhesive area of ​​the first pressure-sensitive adhesive layer 21 to the adherend (here, the printing drum), allowing for better adhesion.

[0023] As shown in Figure 2, the embossed portions 11 are arranged in a square lattice pattern in a plan view. There are no particular limitations on how the embossed portions 11 extend in a plan view; for example, they may extend linearly or curvedly. The ends of the embossed portions 11 preferably reach the edges of the first release liner 10.

[0024] If the embossed portion 11 is not in a grid pattern but is configured as a single line as shown in Fig. 7, air can only escape along the single line, making it difficult to remove air. In contrast, the fixing sheet 1 according to this embodiment is configured in a square grid pattern in a plan view, so air can be removed in four directions, allowing air to be removed efficiently. The shape of the embossed portion 11 in a plan view is not particularly limited as long as it is grid-like.

[0025] The shape of the embossed portion 11 described above is transferred in an inverted manner to the adjacent first pressure-sensitive adhesive layer 21, resulting in the formation of grooves in the first pressure-sensitive adhesive layer 21. These grooves expel air that gets trapped between the adherend and the first pressure-sensitive adhesive layer 21 during application, thereby suppressing swelling.

[0026] The embossed portion 11 may be formed by, for example, embossing the surface of the first release liner 10, but is not limited to this and may also be formed by a printing technique such as screen printing.

[0027] As shown in FIG. 1, the double-sided tape 20 has a first adhesive layer 21, a supporting substrate 22, and a second adhesive layer 23.

[0028] The first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 23 are not particularly limited and may be formed of a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, or a urethane pressure-sensitive adhesive. These pressure-sensitive adhesives may be used alone or in combination of two or more. The pressure-sensitive adhesive may also contain a cross-linking agent. The pressure-sensitive adhesive layers 21 and 23 are obtained, for example, by applying a pressure-sensitive adhesive composition to the first release liner 10 and the second release liner 30, followed by drying. The thickness of the pressure-sensitive adhesive layers 21 and 23 is, for example, 10 μm or more and 100 μm or less, but is not limited thereto.

[0029] The material that constitutes the support substrate 22 is polyethylene terephthalate (PET). PET is a material that does not stretch easily, and therefore has excellent operability when adhering the double-sided tape 20 to an adherend.

[0030] The thickness of the support substrate 22 is less than 50 μm, preferably 12 to 38 μm, but is not limited to this. For example, if the thickness of the support substrate 22 is less than 12 μm, it may be too thin and difficult to process. Note that the present invention also includes configurations in which the thickness of the support substrate 22 is less than 12 μm.

[0031] The thickness of the support substrate 22 is preferably smaller than the thickness of the pressure-sensitive adhesive layers 21, 23. This configuration allows the weight of the double-sided tape 20 to be reduced, improving workability when adhering the double-sided tape 20 to an adherend. Furthermore, this configuration reduces the repulsive force of the support substrate 22 as it tries to return to its original shape when a laminate 5 consisting of a flexographic plate 60 / double-sided tape 20 / first release liner 10 is rolled, as shown in FIG. 3, thereby suppressing the occurrence of tunneling. If the thickness of the support substrate 22 is too thin, workability decreases.

[0032] The second release liner 30 is releasably disposed on the surface of the second pressure-sensitive adhesive layer 23 of the double-sided tape 20. The second release liner 30 may have a configuration in which a thermoplastic resin such as polyethylene is laminated to a paper substrate such as kraft paper, fine paper, glassine paper, or coated paper, and a release agent layer made of a release agent such as silicone is further provided, but is not limited to such a configuration. The thickness (total thickness) of the second release liner 30 is, for example, 50 to 200 μm, but is not limited to this.

[0033] Second release liner 30 has embossed portion 31 with an embossed shape on the surface adjacent to second pressure-sensitive adhesive layer 23 .

[0034] Embossed portion 31 is composed of a plurality of ridges extending linearly along the surface of second release liner 30. The height of the embossed portion 31 is, for example, 5 to 20 μm, but is not limited to this.

[0035] The embossed portion 31 has a cross-sectional shape, such as a triangle, rectangle, trapezoid, a polygon with rounded vertices, or a substantially semicircular shape, in a cross section perpendicular to the direction extending along the surface of the second release liner 30. However, the cross-sectional shape in the cross section is not limited to these and can be designed appropriately. The cross-sectional area of ​​the embossed portion 31 is, for example, 2500 μm 2 It is preferable that the cross-sectional area of ​​the embossed portion 31 is less than 2500 μm. This configuration can improve water resistance. If the cross-sectional area of ​​the embossed portion 31 is too large, there is a high possibility that water will penetrate through the embossed portion 31 during cleaning. The threshold value of the cross-sectional area of ​​the embossed portion 31 is 2500 μm. 2 Not limited to.

[0036] It is preferable that the embossed portion 31 is configured so as to taper toward the support substrate 22 side of the double-sided tape 20 in the stacking direction in a cross section perpendicular to the direction extending along the surface of the second release liner 30. This configuration improves the wettability of the transferred adhesive layer 23, improving water resistance, and also increases the adhesive area of ​​the adhesive layer 23 to the adherend (here, the flexographic plate 60), allowing for better adhesion.

[0037] As shown in Figure 2, the embossed portions 31 are arranged in a square lattice pattern in a plan view. There are no particular limitations on how the embossed portions 31 extend in a plan view; for example, they may extend linearly or curvedly. The ends of the embossed portions 31 preferably reach the edges of the second release liner 30.

[0038] The shape of the embossed portion 31 described above is transferred in an inverted manner to the adjacent second pressure-sensitive adhesive layer 23, resulting in the formation of grooves in the second pressure-sensitive adhesive layer 23. These grooves expel air that gets trapped between the adherend and the second pressure-sensitive adhesive layer 23 during application, thereby suppressing swelling.

[0039] The embossed portion 31 may be formed by, for example, embossing the surface of the second release liner 30, but is not limited to this and may also be formed by a printing technique such as screen printing.

[0040] Next, a method of using the fixing sheet 1 according to this embodiment will be described.

[0041] First, the worker peels off the second release liner 30 from the prepared fixing sheet 1 to expose the second adhesive layer 23. Then, the worker attaches the flexographic plate 60 to the exposed second adhesive layer 23. The thickness of the flexographic plate 60 is, for example, 7 mm, but is not limited to this.

[0042] Next, as shown in Figure 3, laminate 5 consisting of flexographic plate 60 / double-sided tape 20 / first release liner 10 is wound into a roll. Here, for example, if the thickness of support substrate 22 is 50 µm or greater, tunneling may occur at the interface between flexographic plate 60 and second pressure-sensitive adhesive layer 23, and at the interface between first release liner 10 and first pressure-sensitive adhesive layer 21.

[0043] In contrast, since the thickness of the support substrate 22 of the fixing sheet 1 according to this embodiment is less than 50 μm, no tunneling was observed at the interface between the flexographic plate 60 and the second adhesive layer 23, and at the interface between the first release liner 10 and the first adhesive layer 21.

[0044] Next, the first release liner 10 is continuously peeled off from the roll-shaped laminate 5, while the first pressure-sensitive adhesive layer 21 is adhered to a printing drum (not shown).

[0045] Next, ink is applied to the flexographic plate 60 and transferred onto a printing object such as cardboard, etc. After transfer, the flexographic plate 60 is washed.

[0046] When cleaning the flexographic plate 60, if the embossed portions are made too large or the pitch of the embossed portions is made too small, water may seep in through the embossed portions during cleaning.

[0047] In the fixing sheet 1 according to this embodiment, the embossed portions 11, 31 are configured to become thinner toward the support substrate 22 side in the stacking direction, which makes it difficult for water to enter from the ends, thereby improving water resistance. On the other hand, air can be discharged.

[0048] As described above, the fixing sheet 1 according to this embodiment includes a double-sided tape 20 having pressure-sensitive adhesive layers 21, 23 on both sides of a support substrate 22 made of PET, and release liners 10, 30 disposed on both sides of the double-sided tape 20 in the stacking direction and having embossed sections 11, 31, the embossed sections 11, 31 being formed in a lattice pattern when viewed from the stacking direction, and the thickness of the support substrate 22 being less than 50 μm. The fixing sheet 1 configured in this manner has air-releasing properties because the embossed sections 11, 31 are formed in a lattice pattern. Furthermore, the thickness of the support substrate 22 being less than 50 μm can suppress the occurrence of tunneling. From the above, it is possible to provide a fixing sheet 1 that suppresses the occurrence of tunneling, has air-releasing properties, and is water-resistant.

[0049] Furthermore, the embossed portions 11, 31 are configured to taper toward the support substrate 22 in the stacking direction in a cross-sectional view. This configuration improves the wettability of the transferred pressure-sensitive adhesive layer 21, improving water resistance, and also increases the adhesive area of ​​the pressure-sensitive adhesive layer 21 to the adherend, allowing for better adhesion.

[0050] Furthermore, the support substrate 22 has a smaller thickness than the pressure-sensitive adhesive layers 21, 23. This configuration allows the weight of the double-sided tape 20 to be reduced, improving workability when adhering the double-sided tape 20 to an adherend. Furthermore, this configuration reduces the repulsive force of the support substrate 22 as it tries to return to its original shape when a laminate 5 consisting of a flexographic plate 60 / double-sided tape 20 / first release liner 10 is rolled, as shown in FIG. 3, thereby suppressing the occurrence of tunneling.

[0051] The effects of the present invention will be explained using the following examples and comparative examples, but the present invention is not limited to the configurations of the following examples.

[0052] Example 1 As Example 1, a release liner was prepared in which the embossed portions had a height of 30 μm, a width of 80 μm, and a pitch of 800 μm, and the embossed portions had a hexagonal lattice pattern as shown in schematic diagrams of Figures 4 and 5. A fixing sheet was produced using this release liner and a double-sided tape with a support substrate thickness of 25 μm.

[0053] <Example 2> As Example 2, a release liner was prepared in which the embossed portions had a height of 10 μm, a width of 60 μm, and a pitch of 800 μm, and the embossed portions had a square lattice pattern as shown in schematic diagrams of Figures 1 and 2. A fixing sheet was produced using this release liner and a double-sided tape with a support substrate thickness of 25 μm.

[0054] <Comparative Example 1> As Comparative Example 1, a release liner was prepared in which the embossed portions had a height of 20 μm, a width of 8 μm, and a pitch of 250 μm, and the embossed portions had a square lattice pattern as shown in schematic diagrams of Figures 2 and 6. A fixing sheet was produced using this release liner and a double-sided tape with a support substrate thickness of 50 μm.

[0055] <Comparative Example 2> As Comparative Example 2, a release liner was prepared in which the embossed portions had a height of 30 μm, a width of 80 μm, and a pitch of 800 μm, and the embossed portions had a hexagonal lattice pattern as shown in schematic diagrams in Figures 4 and 5. A fixing sheet was produced using this release liner and a double-sided tape with a support substrate thickness of 50 μm.

[0056] <Comparative Example 3> As Comparative Example 3, a release liner was prepared in which the embossed portion had a height of 30 μm, a width of 100 μm, and a pitch of 700 μm, and the embossed portion was linear as shown in the schematic diagrams of Figures 5 and 7. A fixing sheet was produced using this release liner and a double-sided tape with a support substrate thickness of 50 μm.

[0057] <Evaluation> The following table shows the evaluation results for air release, tunneling, and water resistance. Air release was evaluated by observing the ease with which air escaped when applying a squeegee to the adherend. Specifically, a 10 mm diameter air pocket was created and its disappearance was assessed using finger pressure. A ◯ indicates that the air pocket disappeared satisfactorily, while a × indicates that the air pocket remained. Regarding tunneling, PET 188 μm and PET 50 μm laminates were stored in a cylindrical shape with a diameter of 300 mm (storage: 1 week) and checked for the presence or absence of lifting. A ◯ indicates that tunneling was effectively suppressed, while a × indicates that tunneling occurred significantly. Regarding water resistance, the appearance of a laminated sample of PET 188 μm and PET 50 μm laminated together was examined after a water immersion test (24 hours). A ◯ indicates that water did not penetrate, and a × indicates that water penetrated.

[0058] [Table 1]

[0059] The fixing sheets according to Examples 1 and 2 were evaluated as good in terms of air release properties, tunneling properties, and water resistance.

[0060] In Comparative Example 1, the air release property and tunneling property were evaluated as poor. In Comparative Example 2, the tunneling property was evaluated as poor. In Comparative Example 3, the air release property, tunneling property, and water resistance were evaluated as poor.

[0061] The configuration of the fixing sheet 1 according to the present invention has been described above through the embodiments, but the present invention is not limited to the above-described embodiments and can be modified in various ways within the scope of the claims. [Explanation of symbols]

[0062] 1 fixed seat, 10 first release liner, 11 embossed part, 20 double-sided tape, 21 first adhesive layer, 22 supporting base material; 23 second adhesive layer, 30 second release liner, 31 Embossed section.

Claims

1. a double-sided tape having pressure-sensitive adhesive layers on both sides of a support substrate made of PET; release liners disposed on both sides of the double-sided tape in the lamination direction and having embossed portions; The embossed portion is formed in a lattice shape when viewed from the stacking direction, The thickness of the support substrate is less than 50 μm.

2. The fixing sheet according to claim 1 , wherein the embossed portion is configured to taper toward the support substrate in the stacking direction in a cross-sectional view.

3. The fixing sheet according to claim 1 or 2, wherein the supporting substrate has a thickness smaller than that of the adhesive layer.

4. The cross-sectional area of ​​the embossed portion is 2500 μm ２ The fixing sheet according to claim 1 or 2, wherein the thickness is less than 1 / 2 mm.

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