JP2004323824A - Pressure-sensitive adhesive processing sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive processing sheet capable of being easily adhered, without causing blisters, by preventing air from being caught in the sheet, given at a low cost, capable of being easily adhered again, and excellent in applicability. <P>SOLUTION: This pressure-sensitive adhesive processing sheet is composed of a sheet base material A and a pressure-sensitive adhesive layer B which has many small hollow parts b1 and many projection parts b2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an adhesive sheet used for stickers, labels, and the like.

  A conventional pressure-sensitive adhesive sheet is composed of a pressure-sensitive adhesive sheet formed by providing a pressure-sensitive adhesive layer flat on a sheet base material, and a release sheet bonded to the flat pressure-sensitive adhesive layer. The release-treated surface of the release sheet is usually flat, and the release sheet is peeled off, and the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive sheet is attached to an adherend and used.

Such an adhesive-processed sheet often entraps air between the adhesive-processed sheet and the adherend, causing air pockets to become blisters, causing a convex portion on the surface side of the adhered adhesive-processed sheet, and a marked appearance. There was a problem of spoiling. This problem was particularly remarkable when the area of the pressure-sensitive adhesive sheet was large or when the surface of the adherend was smooth.
When the adherend is made of plastic (polycarbonate, acrylic, expanded polystyrene resin, etc.), gas is generated from the surface of the plastic over time, and blisters may be generated on the pressure-sensitive adhesive sheet.
In order to solve the above problems, various pressure-sensitive adhesive sheets have been proposed in Patent Documents 1 and 2 and the like. However, those techniques have lower productivity and higher cost than ordinary adhesive-processed sheets.
Therefore, an object of the present invention is to solve the above-mentioned problem and to provide an inexpensive pressure-sensitive adhesive sheet which does not cause blisters at the time of adhering or after adhering, has excellent productivity, and is inexpensive.

Utility Model Registration No. 2503717 JP-A-3-243677

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that the sheet base material A and the pressure-sensitive adhesive layer B having a large number of small depressions b1 and a large number of small protrusions b2 are formed. The use of the pressure-sensitive adhesive sheet is characterized by low production costs and no blistering at the time of sticking to the adherend. The invention has been completed.
That is, the present invention provides a pressure-sensitive adhesive sheet characterized by comprising a pressure-sensitive adhesive layer B having a sheet base material A, a number of small depressions b1, and a number of small protrusions b2.

  In a preferred embodiment of the pressure-sensitive adhesive sheet of the present invention, a sheet base material A, a pressure-sensitive adhesive layer B having a large number of small depressions b1 and a large number of small projections b2, a large number of raised portions c1, and a large number of perforated structures c2 It is preferable to comprise the release sheet C having The pressure-sensitive adhesive layer B has a basic flat surface on the side in contact with the release sheet C, the small depression b1 is depressed from the basic flat surface, and the small protrusion b2 projects from the basic flat surface. Is preferred. The small depression b1 is recessed from the basic flat surface at a depth of 1 μm to the thickness of the pressure-sensitive adhesive layer B, and the small protrusion b2 is projected from the basic flat surface at a height of 1 to 150 μm. preferable.

  The basic flat surface and the horizontal cross-sectional shape of the small recess b1 are at least one selected from the group consisting of a circle, an ellipse, a donut, a crescent, and an n-gon (n is a natural number of 3 or more). It is preferably a shape, more preferably at least one shape selected from a donut shape and a crescent shape. Similarly, the basic flat surface and the horizontal cross-sectional shape of the small protrusion b2 are at least selected from the group consisting of a circle, an ellipse, a donut, a crescent, a gourd, and an n-gon (n is a natural number of 3 or more). It is preferably at least one shape, more preferably at least one shape selected from the group consisting of a donut shape, a crescent shape, and a gourd shape, and the base of the small recessed portion b1 on the basic flat surface. It is particularly preferable that the shape is formed adjacent to the part contour.

In addition, it is preferable that the small depressions b1 are separated from each other and scattered on the basic flat surface. The small depressions b1 are preferably distributed at a frequency of 10 to 10,000 / cm ² . Further, it is preferable that the small protrusions b2 are separated from each other and scattered on the basic flat surface. The small projections b2 are preferably distributed at a frequency of 10 to 10,000 / cm ² .
The width of the base of the small protrusion b2 on the basic flat surface is preferably 1 to 1,500 μm.
The thickness of the protruding portion c1 of the release sheet C is preferably 1 μm or more than the thickness of the non-perforated portion of the release sheet C. Also, the release sheet C is preferably made of a thermoplastic resin.

FIG. 1 is an example of a cross-sectional view of the basic structure of the pressure-sensitive adhesive sheet of the present invention, and FIG. 2 is a schematic view of the pressure-sensitive adhesive sheet viewed from a vertical direction (overlook) on the pressure-sensitive adhesive layer B side.
FIG. 3 is an example of a cross-sectional view of another basic configuration of the pressure-sensitive adhesive sheet according to the present invention. FIG. 4 is a schematic view of the pressure-sensitive adhesive sheet viewed from a vertical direction (overlook) on the pressure-sensitive adhesive layer B side.
In the figure, 1 is a sheet substrate A, 2 is a pressure-sensitive adhesive layer B, 3 is a small depression b1, 4 is a small protrusion b2, and 5 is a basic flat surface.

By providing the raised portion c1 and the perforated structure c2 on the release sheet C, the shape of the release sheet C is transferred to the pressure-sensitive adhesive layer B at the time of pressure-sensitive adhesive processing, and a number of small depressions b1 and The small protrusion b2 can be formed.
By having such small depressions b1 and small projections b2, when the pressure-sensitive adhesive sheet is lightly attached to the adherend, the small projections b2 of the pressure-sensitive adhesive layer B first adhere to the adherend, and the adhesive There is a gap between the basic flat surface of the layer B and the surface of the adherend that communicates with the outside. As a result, most of the air between the pressure-sensitive adhesive sheet and the adherend can be evacuated to the outside through the gap communicating with the outside, and large non-uniform blisters do not occur during the application. In addition, since the minute air remaining between the pressure-sensitive adhesive sheet and the adherend accumulates in the small depression b1, the construction can be performed without impairing the appearance at all.

In addition, since the pressure-sensitive adhesive layer B has a basic flat surface, when the pressure-sensitive adhesive layer B of the pressure-sensitive adhesive sheet is strongly pressed on the adherend, the basic flat surface of the pressure-sensitive adhesive layer B is continuously formed on the adherend surface. The gap that has adhered and communicated between the pressure-sensitive adhesive layer B and the adherend is eliminated, and a strong adhesive strength can be obtained. In addition, even during strong pressure bonding, the small depression b1 is not adhered to the adherend, and the gas generated with the passage of time when the adherend is plastic is uniformly accumulated in the small depression b1, No large and uneven blisters are generated even after construction, and the appearance is not significantly impaired.
Further, when the pressure-sensitive adhesive sheet is lightly stuck to the adherend, the small protrusions b2 of the pressure-sensitive adhesive layer B first come into close contact with the adherend, so that the contact area becomes small. Therefore, when re-attaching, it is easy to peel off and re-attach again. In addition, it is possible to suppress a decrease in adhesive strength due to peeling.
From the above advantages, for example, when the pressure-sensitive adhesive sheet of the present invention is applied as a large-sized label, positioning and the like are easy, and no skill is required for the work, the work is completed in a short time, and a beautiful finish is obtained. Becomes possible.

  Use of the pressure-sensitive adhesive sheet of the present invention facilitates re-sticking and does not generate large and uneven blisters during and after sheet construction, and is useful for large-sized stickers, labels, signs, signs, namers, tack sheets, etc. Can be used for

(Sheet substrate A)
The material of the sheet substrate A is not particularly limited, and various substrates such as natural paper, plastic film, synthetic paper, woven fabric, and nonwoven fabric can be used. In particular, a plastic film such as a polyolefin or polyester, or a synthetic paper made of a polyolefin or polyester is basically a substrate having poor air permeability, so that the technique of the present invention can be preferably applied. Further, these base sheets are preferable because the base material has high strength and the sheet base material is not broken at the time of peeling and can be peeled cleanly.
The thickness of the sheet substrate A is 30 to 2000 μm, and preferably 40 to 1500 μm.

(Release sheet C)
Examples of the material of the release sheet C include thermoplastic resin sheets such as polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon, and the like. And metal foil, a composite of a combination of a metal foil and a thermoplastic resin sheet, a combination of a metal foil and natural paper, and the like. Preferably, it is a thermoplastic resin sheet, and more preferably, it is a polypropylene film.

The release sheet C is subjected to a perforation process to be described later in order to provide a raised portion c1 and a perforated structure c2. The surface on the side of the release treatment surface before the perforation treatment forms the basic flat surface of the pressure-sensitive adhesive layer B later, and is preferably smooth, but may be roughened for the purpose of controlling the release performance. is there.
Before applying the release agent on the release sheet C, the surface of the release sheet C may be subjected to surface treatment such as corona discharge, flame treatment, and ozone treatment.
Examples of the release agent include a silicone resin, a fluorine resin, an aminoalkyd resin, and a polyester resin, and a silicone resin is preferable. These are used as emulsion type, solvent type or solventless type.
The thickness of the release sheet C of the present invention is preferably from 5 to 150 μm, more preferably from 10 to 130 μm, from the viewpoint of handling strength, ease of perforation, and the like.

(Punching process)
The perforated peripheral portion of the release sheet C of the present invention is rolled up in the thickness direction of the sheet by being thermally or plastically deformed by a perforation processing method described later, and the thickness of the non-perforated portion of the sheet (or the perforation processing). (The average thickness of the previous sheet). In the present invention, a portion where the thickness is increased by the perforation processing on the release sheet C is referred to as a raised portion c1. The thickness of the raised portion c1 is preferably 1 μm or more than the thickness of the non-perforated portion of the release sheet C (or the average thickness of the release sheet before the perforation process), preferably 1 μm to the pressure-sensitive adhesive layer. The thickness is more preferably equal to the thickness of B, and particularly preferably in the range of 3 μm to the thickness of the pressure-sensitive adhesive layer B.
When the thickness of the protruding portion c1 is less than 1 μm compared to the thickness of the non-perforated portion, a sufficient protrusion height cannot be obtained on the release sheet C, and the protrusion sheet c1 is formed on the pressure-sensitive adhesive layer B at the time of pressure-sensitive adhesive processing described later. Also, the depth of the depression of the small depression b1 cannot be obtained, and the blister prevention, which is the gist of the present invention, cannot be achieved.

In the release sheet C, a perforation structure c2 is generated by the perforation processing. The perforation structure c2 may be a through hole or a semi-through hole (a hole that does not penetrate in the thickness direction of the release sheet). In addition, the perforated structure c2 of the release sheet C may have a shape or a hole diameter that changes in the thickness direction as long as the constitutional requirements of the present invention are satisfied. The release sheet C may be one in which a through-hole is formed by a perforation process, another substrate is laminated, and one side of the through-hole is closed to make the perforated structure c2 a semi-through-hole.
The depth of the perforated structure c2 is not particularly limited as long as the performance can satisfy the constituent requirements of the present invention. Above all, it preferably has a depth of 1 μm or more from the surface of the release sheet C, more preferably has a depth of 1 μm to the thickness of the release sheet C, and more preferably has a depth of 3 μm to the thickness of the release sheet C. It is particularly preferred to have a depth in the range.

The hole diameter of the perforated structure c2 is also not particularly limited as long as it can have the performance satisfying the constituent requirements of the present invention. A specific example is 5 to 2,000 μm, preferably 50 to 1,500 μm, within a range that can be formed by the following perforation processing method.
The thickness (height) of the protruding portion c1 and the depth of the perforated structure c2 are determined by cutting out a cross section of the release sheet C after perforation with a microtome, performing ion etching and gold vapor deposition with a commercially available ion coater, and then scanning electron beams. It was calculated from the cross-sectional form with a microscope (trade name: S-3000N, manufactured by Hitachi High-Technologies Corporation).
As a method of the perforation processing for providing the raised portion c1 and the perforated structure c2 on the release sheet C, at least one selected from a hot needle perforation method, a laser beam perforation method, an electron beam irradiation perforation method, a plasma perforation method, and a high-pressure discharge perforation method. Two methods can be applied, and they can be appropriately selected and combined according to the material, thickness, processing speed, and hole diameter of the release sheet C.

(Adhesive layer B)
The type (material) and thickness (coating amount) of the pressure-sensitive adhesive layer B of the present invention are determined by the material and thickness of the base material used for the sheet base material A and the environment (material and state of the adherend, indoor And outdoor, temperature, humidity, period of use, etc.), the desired adhesive strength, and the like, and are not particularly limited.
As an example of the pressure-sensitive adhesive layer B, a commonly used water-based or solvent-based pressure-sensitive adhesive can be applied and dried. As the type (material), natural rubber type, synthetic rubber type, acrylic type, urethane type, EVA type, silicone type and the like can be used. These polymer type pressure-sensitive adhesives can be used in organic solvent solution, emulsion or dispersion. It can be used in a form dispersed in an aqueous solution.

(Coating method)
There are two methods of providing the pressure-sensitive adhesive layer B on the sheet base material A: direct coating in which the pressure-sensitive adhesive is directly applied to the sheet base material A, and indirect coating in which the pressure-sensitive adhesive is once applied to the release sheet C. However, the technology of the present invention is applicable to both, and there is no particular limitation.
The method for applying the pressure-sensitive adhesive is not particularly limited. For example, comma-coat coating, reverse-coat coating, gravure-coat coating, kiss-coat coating, knife-coat coating, bar-coat coating, curtain-coat coating, and transfer of adhesive applied by these methods to process paper Transfer method.
The thickness (coating amount) is generally used in a dry weight range of 0.5 to 400 g / m ² or a dry thickness of 0.5 to 400 μm.

(Method of forming small recesses b1 and small protrusions b2)
The small dents b1 and the small protrusions b2 provided in the pressure-sensitive adhesive layer B are formed by using the perforated release sheet C when the pressure-sensitive adhesive layer B and the release sheet C are laminated (in the case of indirect coating, peeling is performed). When the pressure-sensitive adhesive is applied to the sheet C), the raised portions c1 of the release sheet C bite into the basic flat surface of the pressure-sensitive adhesive layer B to form the corresponding small depressions b1. At the same time, the pressure-sensitive adhesive flows into the perforated structure c2 of the release sheet C from the basic flat surface of the pressure-sensitive adhesive layer B to form the corresponding small projections b2. These small depressions b1 correspond to the protrusions c1, and the small protrusions b2 correspond to the perforation structure c2.

In addition, in the case of the direct coating in which the pressure-sensitive adhesive layer B is directly provided on the sheet base material A, when the release sheet C is laminated, the raised portion c1 of the release sheet C bites into the basic flat surface of the pressure-sensitive adhesive layer B. At the same time as forming the corresponding small depression b1, the extruded adhesive is formed around the small depression b1 as a small protrusion b2 like a dike. In this case, the resulting small depression b1 corresponds to the raised portion c1, but the small projection b2 does not necessarily correspond to the perforated structure c2.
The depression depth of the small depression b1 is preferably in the range of 1 μm to the thickness of the pressure-sensitive adhesive layer B from the basic flat surface of the pressure-sensitive adhesive layer B, and 3 μm to the thickness of the pressure-sensitive adhesive layer B from the basic flat surface. More preferably, it is within the range. When the depth of the small depression b1 is less than 1 μm, the small depression b1 also easily adheres to the adherend, and the remaining minute air or gas generated from the adherend is unevenly accumulated, resulting in blistering. And the appearance is remarkably impaired.

The protrusion height of the small protrusion b2 is preferably in the range of 1 μm to 150 μm from the basic flat surface of the pressure-sensitive adhesive layer B, and more preferably in the range of 3 μm to 100 μm from the basic flat surface. When the height of the small projections b2 is less than 1 μm, the gap between the pressure-sensitive adhesive layer B and the adherend communicating with the outside becomes smaller when the pressure-sensitive adhesive sheet is adhered to the adherend, so that air escape becomes worse. As a result, large and uneven blisters are generated, and the appearance is remarkably impaired. On the other hand, if it is larger than 150 μm, the basic flat surface cannot be brought into contact with the adherend even if it is strongly pressed after being adhered to the adherend.
The depression depth of the small depression b1 and the protrusion height of the small protrusion b2 are adjusted by adjusting the temperature of the processed pressure-sensitive adhesive sheet to a temperature equal to or lower than the glass transition point of the pressure-sensitive adhesive, and cutting out a cross section using a microtome. After ion etching and gold vapor deposition with a coater, it was calculated from the cross-sectional morphology using a scanning electron microscope (trade name: S-3000N, manufactured by Hitachi High-Technologies Corporation).

The shape of the small depression b1 is essentially a transfer of the shape of the protrusion c1 of the release sheet C, and is not particularly limited, but is a cross section in the horizontal direction with respect to the basic flat surface of the pressure-sensitive adhesive layer B. At least one shape selected from the group consisting of a circle, an ellipse, a donut, a crescent, and an n-gon (n is a natural number of 3 or more) can be preferably selected, and in particular, any one of a donut and a crescent It is preferable that the shape is at least one or more selected.
The above-mentioned shape is a suitable shape that can be selected in the perforating treatment of the release sheet C of the present invention, and a donut shape and a crescent shape are particularly preferable in that they can be formed by an inexpensive treatment process.

Similarly, the basic flat surface and the horizontal cross-sectional shape of the small protrusion b2 are at least selected from the group consisting of a circle, an ellipse, a donut, a crescent, a gourd, and an n-gon (n is a natural number of 3 or more). One or more shapes can be preferably selected, and it is more preferable that the shape is at least one or more selected from the group consisting of a donut shape, a crescent shape, and a gourd, and the contour of the small depression b1 at the base of the basic flat surface. It is particularly preferable that the shape is formed adjacent to the outer periphery along the line.
By providing the above-mentioned shape, even if minute blisters are generated, they are hardly conspicuous, and the appearance is not greatly impaired.
According to the technique of the present invention, the small depression b1 and the small projection b2 may be present independently and separately from each other, but when the small projection b2 is formed adjacent to the small depression b1. The fine air remaining between the pressure-sensitive adhesive layer B and the adherend or the gas generated from the adherend is concentrated and taken into the small depression b1 adjacent to the small protrusion b2, resulting in an uneven blister. Can be effectively suppressed.

It is preferable that many small depressions b1 exist on the basic flat surface, and they are separated from each other and scattered. When the small depressions b1 exist densely, the ratio of the basic flat surface decreases, and the adhesive strength of the pressure-sensitive adhesive base sheet decreases only in that portion. If it is sparse, there is a risk that blisters may be generated because the minute air or gas between the adhesive layer B and the adherend cannot be taken in.
The small depressions b1 are preferably distributed at a frequency of 10 to 10,000 / cm ² , and more preferably at a frequency of 15 to 5,000 / cm ² .
If the distribution frequency of the small depressions b1 is less than 10 / cm ^2, it is not preferable because the blister prevention effect decreases. If it exceeds 10,000 / cm ² , the required adhesive strength cannot be obtained, which is not preferable.
It is particularly preferable that the small depressions b1 are evenly distributed on the basic flat surface from the viewpoint of preventing blisters.

Similarly, a large number of small protrusions b2 are present on the basic flat surface, and they are preferably separated from each other and scattered. When the small protrusions b2 are densely provided, the contact area with the adherend is reduced, and a sufficient adhesive strength cannot be obtained even when pressure is applied strongly. When the pressure-sensitive adhesive sheet is adhered to the adherend when it is sparse, the gap between the pressure-sensitive adhesive layer B and the adherend communicating to the outside becomes smaller, so that air escape becomes worse, and as a result, it becomes larger. There is a risk of generating uneven blisters.
The small protrusions b2 are preferably distributed at a frequency of 10 to 10,000 / cm ² , more preferably at a frequency of 15 to 5,000 / cm ² .

When the distribution frequency of the small projections b2 is less than 10 / cm ² , large and uneven blisters are generated and the appearance is remarkably impaired, which is not preferable. If it exceeds 10,000 / cm ² , the required adhesive strength cannot be obtained, which is not preferable.
The distribution frequency of the small protrusions b2 on the basic flat surface may be uniform or non-uniform as long as it is within the above range. If uniform, the entire surface of the sheet can be provided with an even adhesive force, thereby improving workability. If it is not uniform, a label or the like having a partially weakened adhesive force can be created, and the present invention can be applied to a label with a coupon and the like.
Regarding the horizontal size of the small protrusion b2, the maximum width of the base portion on the basic flat surface is preferably 1 to 1,500 μm, more preferably 3 to 1,000 μm.

If the maximum width of the small projections b2 is less than 1 μm, it is not preferable because minute air or gas between the pressure-sensitive adhesive layer B and the adherend cannot be taken in, causing blisters. If the width of the small protrusion b2 is larger than 1,500 μm, the ratio of the area occupied by the basic flat surface decreases, and the required adhesive strength cannot be obtained, which is not preferable.
The sheet substrate A of the pressure-sensitive adhesive sheet of the present invention can be decorated by various printing methods. As a printing method, not only printers such as an electrophotographic system, a fusion heat transfer system, a sublimation heat transfer system, a rewritable marking, and an inkjet system, but also letterpress printing, gravure printing, flexographic printing, solvent type offset printing, and ultraviolet curing type Various printing methods such as offset printing and screen printing can be applied.

Hereinafter, the present invention will be specifically described with reference to Examples, Comparative Examples, and Test Examples. Materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited by the following specific examples.
[Example 1]
A 60-μm-thick polypropylene film (trade name: Pyren P2761; manufactured by Toyobo Co., Ltd.) was subjected to a through-perforation process using a hot-needle perforation method, and the rolled surface of the perforated portion was subjected to a silicone treatment. Release sheet C was obtained. The hole diameter was 400 μm, the number of holes was 60 / cm ² , the depth of the perforated portion was 60 μm (through hole), and the height of the raised portion c1 formed on the periphery of the perforated portion was 60 μm.
Next, an 80 μm-thick synthetic paper (trade name: SGS-80, manufactured by YUPO Corporation) was used as the sheet base A, and a solvent-based acrylic pressure-sensitive adhesive (trade name: Olivine BPS1109, Toyo) was used as the adhesive layer B. Ink Chemical Industry Co., Ltd.) was applied with a comma coater so that the coating amount after drying was 30 g / m ^2, and dried to obtain an adhesive processed sheet (sheet base material A + adhesive layer B). .
The pressure-sensitive adhesive sheet was laminated so that the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet was in contact with the silicone-coated surface of the release sheet C to obtain a pressure-sensitive adhesive sheet. Table 1 shows the physical properties of the obtained pressure-sensitive adhesive sheet.

[Example 2]
The release paper of a commercially available pressure-sensitive adhesive sheet having a thickness of 190 μm (trade name: XJP-190, manufactured by Yupo Corporation) was peeled off, and the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive sheet and the release sheet C obtained in Example 1 were removed. Lamination was performed so that the silicone-treated surfaces were in contact with each other to obtain a pressure-sensitive adhesive sheet. Table 1 shows the physical properties of the obtained pressure-sensitive adhesive sheet.

[Example 3]
On the silicone-treated surface of the release sheet C obtained in Example 1, a solvent-based acrylic pressure-sensitive adhesive (Olivine BPS1109, manufactured by Toyo Ink Chemical Industry Co., Ltd.) was applied as a pressure-sensitive adhesive layer B after drying. Was applied with a bar coater so as to be 30 μm, and dried to obtain a laminate (adhesive layer B + release sheet C).
Next, an 80 μm-thick synthetic paper (trade name: SGS-80, manufactured by YUPO Corporation) as the sheet substrate A and the adhesive layer B of the laminate were laminated to obtain an adhesive processed sheet. . Table 1 shows the physical properties of the obtained pressure-sensitive adhesive sheet.
Throughout Examples 1 to 3, the materials used (sheet base material, adhesive, release sheet, etc.) are all generally available to those skilled in the art, and the release sheet is pre-perforated. No special equipment or processing conditions were used other than the above. Therefore, a special member and a processing step are required as in the currently proposed technology, the productivity is inferior, the cost is not increased, and the pressure-sensitive adhesive sheet capable of solving the problem can be obtained at low cost.

[Comparative Example 1]
A silicone film was applied to a 60 μm-thick polypropylene film (trade name: Pyrene P2761 manufactured by Toyobo Co., Ltd.) to obtain a release sheet C. The same operation as in Example 1 was performed except that the through-hole punching treatment was not performed, to obtain an adhesive sheet. Table 1 shows the physical properties of the obtained pressure-sensitive adhesive sheet.

(Test example)
(Small depression b1 depression depth, small projection b2 protrusion height)
In each of the examples and the comparative examples, the depression depth of the small depression b1 and the projection height of the small projection b2 formed on the pressure-sensitive adhesive layer B were calculated by the above-described method.
(Workability)
After peeling off the release sheet C of the pressure-sensitive adhesive sheet of each of the examples and the comparative examples, lightly attaching the transparent sheet to a transparent and smooth glass plate, and then peeling again, there is no wrinkle or glue residue, and the ease of peeling is as follows. Judgment was made based on
：: easy to peel, no wrinkles or adhesive residue
X: There is resistance during peeling, and wrinkles and adhesive residue occur.
(Prevents blistering)
After peeling off the release sheet C of the pressure-sensitive adhesive sheet of each of the examples and the comparative examples, lightly attaching the transparent sheet to a transparent and highly smooth glass plate, and visually inspecting for the presence or absence of blisters when crimped manually using a valen. Was determined according to the following criteria.
：: No blistering was observed.
X: Large and uneven blisters are generated.
Table 1 shows the evaluation and judgment results in each test example.

It is an example of a sectional view of a basic composition in an adhesion processing sheet of the present invention. FIG. 2 is a schematic view of the pressure-sensitive adhesive sheet of FIG. 1 as viewed from a vertical direction (overhead view) on the pressure-sensitive adhesive layer B side. It is an example of a sectional view of a basic composition in an adhesion processing sheet of the present invention. FIG. 4 is a schematic view of the pressure-sensitive adhesive sheet of FIG. 3 as viewed from a vertical direction (overhead view) on the pressure-sensitive adhesive layer B side.

Explanation of reference numerals

1: Sheet base material A
2: Adhesive layer B
3: Small depression b1
4: Small protrusion b2
5: Basic flat surface

Claims (16)

A pressure-sensitive adhesive sheet comprising a sheet base material A, a pressure-sensitive adhesive layer B having a number of small depressions b1 and a number of small protrusions b2. Claims: A sheet substrate A, an adhesive layer B having a large number of small depressions b1 and a large number of small projections b2, and a release sheet C having a large number of ridges c1 and a large number of perforated structures c2. Item 6. The pressure-sensitive adhesive sheet according to Item 1. The surface of the pressure-sensitive adhesive layer B in contact with the release sheet C has a basic flat surface, the small depressions b1 are depressed from the basic flat surface, and the small protrusions b2 protrude from the basic flat surface. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein The depth of the small depression b1 is in the range of 1 μm to the thickness of the pressure-sensitive adhesive layer B from the basic flat surface of the pressure-sensitive adhesive layer B, and the height of the small protrusion b2 is the basic flat surface of the pressure-sensitive adhesive layer B. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive sheet has a thickness of 1 m to 150 m. At least one shape selected from the group consisting of a circular flat, an elliptical shape, a donut shape, a crescent shape, and an n-gonal shape (n is a natural number of 3 or more), in which the basic flat surface and the horizontal cross-sectional shape of the small recess b1 are horizontal. And the basic flat surface and the horizontal cross-sectional shape of the small protrusion b2 are selected from the group consisting of a circle, an ellipse, a donut, a crescent, a gourd, and an n-gon (n is a natural number of 3 or more). The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive sheet has at least one shape. The cross-sectional shape in the horizontal direction with respect to the basic flat surface of the small recess b1 is at least one or more selected from any one of a donut shape and a crescent shape, and the basic flat surface of the small protrusion b2 is horizontal. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the cross-sectional shape is at least one shape selected from the group consisting of a donut shape, a crescent shape, and a gourd shape. The cross-sectional shape in the horizontal direction with respect to the basic flat surface of the small recess b1 is at least one shape selected from any of a donut shape and a crescent shape, and the small protrusion b2 is a basic flat surface of the small recess b1. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive sheet is formed so as to be adjacent to a surface along a contour of a base portion. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the small depressions (b1) are separated from each other and scattered on the basic flat surface. The pressure-sensitive adhesive sheet according to any one of claims 1 to 8, wherein the small protrusions (b2) are separated from each other on the basic flat surface and are scattered. The small depressions b1 are distributed at a frequency of 10 to 10,000 / cm ² , and the small projections b2 are distributed at a frequency of 10 to 10,000 / cm ^2. The pressure-sensitive adhesive sheet according to claim 1. The pressure-sensitive adhesive sheet according to any one of claims 1 to 10, wherein the maximum width of the base portion of the small protrusion b2 on the basic flat surface is 1 to 1,500 µm. When the pressure-sensitive adhesive sheet is used, the basic flat surface of the pressure-sensitive adhesive layer B and the surface of the adherend are continuously in contact with each other, and there is no gap between the pressure-sensitive adhesive sheet and the surface of the adherend. 12. The pressure-sensitive adhesive sheet according to any one of 11. The release sheet (C) according to claim 2, comprising a plurality of raised portions (c1) and a plurality of perforated structures (c2). 14. The release sheet C according to claim 13, wherein a number of raised portions c1 and a number of perforated structures c2 are formed by the perforation process. The release sheet C according to claim 13, wherein the release sheet C is made of a thermoplastic resin. The release sheet (C) according to any one of claims 13 to 15, wherein the thickness of the raised portion (c1) is 1 µm or more than the thickness of the non-perforated portion.

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