JP6645095B2 - Method for producing pressure-sensitive adhesive sheet, and pressure-sensitive adhesive sheet - Google Patents

Description

  The present invention relates to a method for producing a pressure-sensitive adhesive sheet and a pressure-sensitive adhesive sheet.

A general pressure-sensitive adhesive sheet is composed of a base material, a pressure-sensitive adhesive layer formed on the base material, and a release material provided on the pressure-sensitive adhesive layer as necessary. In the case where a material is provided, the release material is peeled off, and the pressure-sensitive adhesive layer is abutted on the adherend and attached.
By the way, for example, for identification and decoration, for coating masking, for use in protecting the surface of a metal plate, etc., the pressure-sensitive adhesive sheet having a large sticking area, when sticking to the adherend, the adhesive layer and the adherend There is a problem that air pockets are likely to be generated during this process, and that portion becomes "bulging", making it difficult to apply the pressure-sensitive adhesive sheet to the adherend neatly.

In order to solve such a problem, for example, in Patent Document 1, a release material having a fine emboss pattern is brought into contact with the surface of the pressure-sensitive adhesive layer, and a groove having a specific shape is formed on the surface of the pressure-sensitive adhesive layer. A pressure-sensitive adhesive sheet artificially arranged in a predetermined pattern is disclosed.
By using such an adhesive sheet, it is said that "air pockets" generated at the time of sticking to the adherend can escape to the outside via grooves artificially formed on the surface of the adhesive layer. ing.

JP 2001-507732 A

However, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which grooves having a general specific shape are arranged in a predetermined pattern, as described in Patent Document 1, etc., has a difficulty in evacuating air when the width of the groove is small, and the width of the groove is small. If it is too wide, not only is the surface substrate dented and the appearance is inferior, but also the adhesive strength is reduced.
Further, in the pressure-sensitive adhesive sheet, since the grooves are arranged in a predetermined pattern, the adhesive force at a portion where the groove is disposed is locally inferior, and when the pressure-sensitive adhesive sheet is attached to an adherend, the pressure-sensitive adhesive sheet is peeled from the position. Can occur.
On the other hand, when the pressure-sensitive adhesive sheet is re-peeled after being adhered to the adherend, adhesive properties of the pressure-sensitive adhesive sheet are locally different, so that depending on the direction in which the pressure-sensitive adhesive sheet is peeled off, adhesive residue may be left on the adherend. For example, in the case of a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which grooves are arranged in a lattice pattern, when peeled in an oblique direction, adhesive residue may be left on the adherend.
Furthermore, when performing the punching process on the adhesive sheet, there is a possibility that the groove arrangement pattern and the punching pattern may overlap. In this case, there is a problem that the cut depth varies, and the cut cannot be appropriately formed in the adhesive sheet.

In general, in order to easily peel off the release material provided on the pressure-sensitive adhesive sheet, a step of cutting the release material only and providing a trigger for peeling (so-called back cracking) may be performed. In performing this step, it is general that the release material is once peeled off from the pressure-sensitive adhesive sheet, the release material is cut, and then the release material and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet are laminated again.
However, in the pressure-sensitive adhesive sheet described in Patent Document 1, since the embossed liner is used as a release material, it is difficult to follow the emboss pattern of the release material when laminating the release material and the pressure-sensitive adhesive layer again. It is necessary to prepare another release material not subjected to the above.

Further, in Patent Document 1, in order to form a fine structure in the pressure-sensitive adhesive layer, a method of once applying a pressure-sensitive adhesive to an embossed liner to form a pressure-sensitive adhesive layer, and then laminating the pressure-sensitive adhesive layer and a substrate ( have adopted the so-called transfer coating method). However, when a substrate having a low polarity surface, such as a polyolefin-based substrate, is used as the substrate, the method cannot provide sufficient adhesion to the interface between the substrate and the pressure-sensitive adhesive layer.
In addition, unlike a release material made of paper, a release material made of a resin film makes it difficult to form a fine emboss pattern on an adhesive layer.
It is generally known that a tackifier is blended in order to improve the adhesive strength. However, in a multilayer pressure-sensitive adhesive sheet having three or more layers, when a tackifier is contained in an intermediate layer, productivity is increased. It has been confirmed by the present inventors that when attempting to produce a pressure-sensitive adhesive sheet, a problem occurs in that a pressure-sensitive adhesive sheet excellent in air bleeding property and blister resistance cannot be obtained.

  An object of the present invention is to provide a method for producing a pressure-sensitive adhesive sheet capable of producing a pressure-sensitive adhesive sheet having excellent adhesive force, air bleeding property, and blister resistance with high productivity, and a pressure-sensitive adhesive sheet.

  The present inventors have a resin layer formed by laminating a specific layer (Xβ), a layer (Y1), and a layer (Xα) on a base material or a release material, and the surface (α) of the layer (Xα) ) Has found that a method for producing a pressure-sensitive adhesive sheet having tackiness can solve the above problems, and completed the present invention.

That is, the present invention provides the following [1] to [20].
[1] A resin layer obtained by laminating a layer (Xβ), a layer (Y1), and a layer (Xα) in this order on a base material or a release material, and at least the surface (α) of the layer (Xα) Is a method for producing a pressure-sensitive adhesive sheet having one or more recesses in an area (Q) surrounded by a square of 1 mm on each side arbitrarily selected on the surface (α). ,
The layer (Xβ) is formed using a composition (xβ) containing a resin and substantially not containing a tackifier,
The layer (Y1) is formed using a composition (y1) containing a resin and fine particles, substantially not containing a tackifier, and having a content of the fine particles of 15% by mass or more,
The method for producing a pressure-sensitive adhesive sheet, wherein the layer (Xα) is formed using a composition (xα) containing 100 parts by weight of a pressure-sensitive adhesive resin and 1 part by weight or more of a tackifier.
[2] The method for producing a pressure-sensitive adhesive sheet according to the above [1], comprising at least the following steps (1A) and (2A).
Step (1A): a coating (xβ ′) composed of the composition (xβ), a coating (y1 ′) composed of the composition (y1), and a coating composed of the composition (xα) on a substrate or a release material Step of stacking and forming film (xα ′) in this order Step (2A): Simultaneously forming coating film (xβ ′), coating film (y1 ′), and coating film (xα ′) formed in step (1A) Drying and forming a layer (Xβ), a layer (Y1), and a layer (Xα) [3] In the step (1A), the composition (xβ), the composition (y1), and the composition (xα) The method for producing a pressure-sensitive adhesive sheet according to the above [2], wherein a coating film (xβ ′), a coating film (y ′), and a coating film (xα ′) are respectively formed at a coating speed of 8 m / min or more. .
[4] The method for producing a pressure-sensitive adhesive sheet according to the above [1], comprising at least the following steps (1B) and (2B).
Step (1B): On the surface of the substrate or the release material, on the layer (Xβ) formed from the composition (xβ), on the coating (y1 ′) composed of the composition (y1), and on the composition (xα) Step (2B): simultaneously drying the coating (y1 ′) and the coating (xα ′) formed in the step (1B) to form a coating (xα ′) Step (5) of Forming (Y1) and Layer (Xα) In step (1B), using the composition (y1) and the composition (xα) at a coating speed of 8 m / min or more, the coating film (y1 ′) ) And the coating film (xα ′) are formed, respectively.
[6] The pressure-sensitive adhesive sheet according to any one of [2] to [5], wherein an irregular recess is formed on the surface (α) of the layer (Xα) by the step (2A) or (2B). Manufacturing method.
[7] The content of the above [1] to [1], wherein the content of the tackifier contained in the composition (xα) is 400 parts by mass or less based on 100 parts by mass of the adhesive resin in the composition (xα). 6] The method for producing a pressure-sensitive adhesive sheet according to any one of [1] to [6].
[8] The method for producing a pressure-sensitive adhesive sheet according to any one of [1] to [7], wherein the coating amount of the coating film (xα ′) is 1.5 to 800 g / m ² .
[9] The method for producing a pressure-sensitive adhesive sheet according to any one of [1] to [8], wherein the coating amount of the coating film (y1 ′) is 1.5 to 800 g / m ² .
[10] The above-mentioned [1] to [1], wherein the ratio of the coating amount of the coating film (xα ′) and the coating film (y1 ′) [(xα ′) / (y1 ′)] is 100/5 to 100/2000. The method for producing a pressure-sensitive adhesive sheet according to any one of [9].
[11] The method for producing a pressure-sensitive adhesive sheet according to any one of [1] to [10], wherein the content of the tackifier is 2 to 60% by mass relative to the total mass of 100% by mass of the resin layer.
[12] The method for producing a pressure-sensitive adhesive sheet according to any one of the above [1] to [11], wherein the resin contained in the composition (xβ) and the composition (y1) is a pressure-sensitive resin.
[13] The method for producing a pressure-sensitive adhesive sheet according to any one of the above [1] to [12], wherein the pressure-sensitive adhesive resin contained in the composition (xα) is an acrylic resin having a functional group.
[14] The method for producing a pressure-sensitive adhesive sheet according to the above [13], wherein the composition (xα) further contains at least one selected from a metal chelate crosslinking agent, an epoxy crosslinking agent, and an aziridine crosslinking agent.
[15] The method for producing a pressure-sensitive adhesive sheet according to the above [13] or [14], wherein the functional group is a carboxy group.
[16] The pressure-sensitive adhesive sheet according to any one of [1] to [15], wherein the fine particles contained in the composition (y1) are at least one selected from silica particles, metal oxide particles, and smectite. Production method.
[17] A resin layer obtained by laminating a layer (Xβ), a layer (Y1), and a layer (Xα) in this order on a base material or a release material, and at least the surface (α) of the layer (Xα) Is an adhesive sheet having adhesiveness,
Layer (X?) Comprises a resin, a layer formed from a substantially free composition (X?) A tackifier,
The layer (Y1) is a layer formed from the composition (y1) containing a resin and fine particles, substantially not containing a tackifier, and having a content of the fine particles of 15% by mass or more,
A pressure-sensitive adhesive sheet, wherein the layer (Xα) is a layer formed from a composition (xα) containing 100 parts by weight of a pressure-sensitive resin and 1 part by weight or more of a tackifier.
[18] The pressure-sensitive adhesive sheet according to the above [17], having an irregular recess on the surface (α) of the layer (Xα).
[19] the recess, and is formed by self-forming of the resin layer, the adhesive sheet according to the above [18].
[20] The pressure-sensitive adhesive sheet according to any one of the above [17] to [19], wherein the layer (Y1) contains a tackifier.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the adhesive sheet which can manufacture the adhesive sheet excellent in adhesive force, air bleeding property, and blister resistance with high productivity, and an adhesive sheet can be provided.

FIG. 2 is a schematic cross-sectional view of the pressure-sensitive adhesive sheet, showing an example of the configuration of the pressure-sensitive adhesive sheet of the present invention. FIG. 3 is a schematic plan view of the surface (α) when observed from the surface (α) side of the resin layer of the pressure-sensitive adhesive sheet of the present invention. FIG. 3 is a schematic cross-sectional view of the resin layer of the pressure-sensitive adhesive sheet of the present invention, showing an example of the shape of the resin layer on the surface (α) side. FIG. 3 is a diagram for explaining a method of selecting a cross section defined by requirement (II), and is a perspective view of an adhesive sheet of one embodiment of the present invention. FIG. 2 is an example of a schematic view of a cross section (P1) defined by a requirement (II) for the pressure-sensitive adhesive sheet of one embodiment of the present invention. Using a digital microscope, a region (D) arbitrarily selected on the surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Example 1 and enclosed by a rectangle of 8 mm × 10 mm was measured using a digital microscope. ) Is a binarized image of the image taken from the side. Using a digital microscope, a region (D) arbitrarily selected on the surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Example 2 and surrounded by a rectangle of 8 mm × 10 mm was measured using a digital microscope. 2) is a binarized image of the image taken from the side. 5 is a binarized image of an image taken from the surface (α) side of a resin layer, obtained by using a digital microscope for the pressure-sensitive adhesive sheet produced in Comparative Example 1.

In the present invention, for example, the description of “YY containing an XX component as a main component” or “YY mainly consisting of an XX component” means “the component having the highest content among the components contained in YY is the XX component. There is ". The specific content of the XX component in the description is usually 50% by mass or more, preferably 65 to 100% by mass, more preferably 75 to 100% by mass, based on the total amount of YY (100% by mass). Preferably it is 85-100 mass%.
In the present invention, for example, “(meth) acrylic acid” indicates both “acrylic acid” and “methacrylic acid”, and the same applies to other similar terms.
Furthermore, the lower limit and the upper limit described stepwise in a preferable numerical range (for example, a range of content and the like) can be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60", "preferable lower limit (10)" and "more preferable upper limit (60)" are combined to obtain "10 to 60". You can also.

(Production method of the pressure-sensitive adhesive sheet of the present invention)
In the method for producing the pressure-sensitive adhesive sheet of the present invention (hereinafter, also referred to as “the production method of the present invention”), a layer (Xβ), a layer (Y1), and a layer (Xα) are arranged in this order on a substrate or a release material. It has a laminated resin layer, and at least the surface (α) of the layer (Xα) (hereinafter, also simply referred to as “surface (α)”) has adhesiveness and is arbitrarily selected on the surface (α). It was in the side 1mm area surrounded by a square (Q), pressure-sensitive adhesive sheet wherein the recess is present one or more a method of manufacturing (hereinafter, also referred to as "pressure-sensitive adhesive sheet of the present invention"),
The layer (Xβ) is formed using a composition (xβ) containing a resin and substantially not containing a tackifier,
The layer (Y1) is formed using a composition (y1) containing a resin and fine particles, substantially not containing a tackifier, and having a content of the fine particles of 15% by mass or more,
Layers (X [alpha) is an adhesive resin 100 parts by weight, is formed by using a composition containing a tackifier 1 part by mass or more (X [alpha), a method of manufacturing the pressure-sensitive adhesive sheet.

In the production method of the present invention, the composition (xβ) does not substantially contain a tackifier, the composition (y1) contains 15% by mass or more of fine particles, and does not substantially contain a tackifier. only composition (X [alpha) is, by containing a tacky resin 100 parts by weight tackifier 1 part by mass or more, high-speed coating to be produced, a small recess and the flat surface there are many surfaces (alpha) A pressure-sensitive adhesive sheet having excellent adhesive strength, air bleeding property and blister resistance can be obtained.
According to the production method of the present invention, a layer (Xβ) mainly containing a resin portion (X), a layer (Y1) containing a particle portion (Y1), such as the pressure-sensitive adhesive sheet 1a in FIG. A pressure-sensitive adhesive sheet having a resin layer formed by forming a multilayer structure in which layers (Xα) mainly containing a resin portion (X) are laminated in this order can be manufactured with high productivity.
Although there is no particular limitation on the production method of the present invention, it facilitates formation of a concave portion and a flat surface on the surface (α) of the resin layer, and improves air bleeding property and blister resistance. From the viewpoint of the following, the manufacturing method according to the first embodiment and the manufacturing method according to the second embodiment described below are preferable.

<The manufacturing method of the first embodiment>
The production method of the first embodiment is a method having at least the following steps (1A) and (2A).
Step (1A): a coating (xβ ′) composed of the composition (xβ), a coating (y1 ′) composed of the composition (y1), and a coating composed of the composition (xα) on a substrate or a release material Step (2A): simultaneously forming the coating film (xβ ′), the coating film (y1 ′), and the coating film (xα ′) formed in the step (1A). Drying to form layer (Xβ), layer (Y1), and layer (Xα)

<Production method according to second embodiment>
Manufacturing method of the second aspect is a method comprising at least the following step (1B) and (2B).
Step (1B): On the surface of the substrate or the release material, on the layer (Xβ) formed from the composition (xβ), on the coating (y1 ′) composed of the composition (y1), and on the composition (xα) Step (2B): The coating film (y1 ′) and the coating film (xα ′) formed in the step (1B) are simultaneously dried to form a layer. Step of Forming (Y1) and Layer (Xα) In the production method of the present invention, by the step (2A) or (2B), an irregular concave portion is effectively formed on the surface (α) of the layer (Xα). The shape of the flat surface also becomes irregular by being formed and forming the irregular concave portion.

[Configuration of pressure-sensitive adhesive sheet obtained by the production method of the present invention]
The pressure-sensitive adhesive sheet obtained by the production method of the present invention has a resin layer obtained by laminating a layer (Xβ), a layer (Y1), and a layer (Xα) in this order on a base material or a release material. The surface (α) of the layer (Xα) is an adhesive sheet having tackiness, and the surface (α) has a concave portion.

Figure 1 is a schematic sectional view showing an example of the configuration of the pressure-sensitive adhesive sheet of the present invention.
As the pressure-sensitive adhesive sheet of one embodiment of the present invention, for example, a pressure-sensitive adhesive sheet 1a having a resin layer 12 on a base material 11 as shown in FIG. on the wood 21, and the adhesive sheet 1b having a resin layer 12.

In the pressure-sensitive adhesive sheet of one embodiment of the present invention, at least the surface (α) 12a of the layer (Xα) 12 on the side opposite to the side on which the base material 11 or the release material 21 is provided has tackiness, There is a flat surface 14.
Therefore, from the viewpoint of handleability, as the pressure-sensitive adhesive sheet of another embodiment of the present invention, a release material 22 is further provided on the surface (α) 12a of the resin layer 12 with respect to the pressure-sensitive adhesive sheets 1a and 1b shown in FIG. It is preferable to provide the adhesive sheet 2a, 2b as shown in FIG. 1 (c) or (d).

In the pressure-sensitive adhesive sheet of one embodiment of the present invention, as shown in FIG. 1, the resin layer 12 includes a resin portion (X) containing a resin and a particle portion (Y) made of fine particles.
By including the particle portion (Y) in the resin layer 12, it is possible to improve the shape retention after sticking, and when the obtained pressure-sensitive adhesive sheet is used at a high temperature, the pressure-sensitive adhesive sheet has improved blister resistance. It can be.
Details of the resin portion (X) and the particle portion (Y) are as described below.

In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, the surface (β) 12b (hereinafter, also referred to as “surface (β)”) of the resin layer 12 on the side where the base material 11 or the release material 21 is provided is also tacky. it may have.
Since the surface (β) also has adhesiveness, the adhesiveness between the resin layer 12 and the base material 11 is improved with the adhesive sheets 1a and 2a shown in FIGS. 1 (a) and 1 (c). The pressure-sensitive adhesive sheets 1b and 2b shown in b) and (d) can be double-sided pressure-sensitive adhesive sheets.

[Requirements for recesses and flat surfaces existing on surface (α)]
As shown in FIGS. 1A to 1D, the pressure-sensitive adhesive sheet of the present invention has a concave portion 13 and a flat surface 14 on the surface (α) 12 a of the resin layer 12.
The concave portion 13 present on the surface (α) serves as an air discharge passage for releasing “air pockets” generated when the surface (α) of the resin layer of the pressure-sensitive adhesive sheet of the present invention is adhered to the adherend. It is responsible for.
On the other hand, the flat surface 14 existing on the surface (α) is a surface that directly contacts and adheres to the adherend when bonding to the adherend, and is a portion that affects the adhesive strength of the adhesive sheet.

FIG. 2 is a schematic plan view of the surface (α) when observed from the surface (α) side of the resin layer of the pressure-sensitive adhesive sheet of the present invention.
The concave portion existing on the surface (α) of the resin layer is preferably an irregular concave portion 13 as shown in FIG. 2, but may have a regular concave portion.
However, in one embodiment of the present invention, as shown in FIG. 2, it is preferable that one or more irregular recesses 13 are present on the surface (α) 12 a of the resin layer 12. More preferably, there are a plurality.
The presence of the irregular recesses on the surface (α) of the resin layer makes it possible to obtain a pressure-sensitive adhesive sheet with a good balance of air bleeding property and pressure-sensitive adhesive properties, and further improved.
In addition, due to the presence of a plurality of irregularly shaped recesses, pressure is applied from a certain direction, and even when the shape of a part of the recesses present on the surface (α) is broken, the shape is not formed on the surface (α). The maintained concave portion 13 is easily present, and it is possible to prevent the air escape path from disappearing.

  Note that the length of the concave portion 13 when the concave portion 13 existing on the surface (α) is viewed in a plan view is not particularly limited. That is, the concave portion 13 includes a relatively long groove shape and a relatively short dent shape.

The flat surface existing on the surface (α) of the resin layer is preferably an irregular flat surface 14 as shown in FIG. 2, but may have a regular flat surface.
However, in one embodiment of the present invention, as shown in FIG. 2, it is preferable that at least one irregular flat surface 14 is present on the surface (α) 12a of the resin layer 12; Is more preferably present.
Due to the presence of an irregular flat surface on the surface (α) of the resin layer, unlike the surface of the pressure-sensitive adhesive layer formed using a release sheet having a general emboss pattern, the adhesive strength is locally increased. It is possible to minimize the number of weak portions and portions having poor air bleeding properties. As a result, uniformly excellent air bleeding properties and adhesive properties can be exhibited on the surface (α) of the resin layer.

In the present invention, the term “indefinite” refers to a figure that can draw a center such as a circle or an ellipse, or a fixed shape such as a polygon, has no regular shape, and is similar to an individual shape. It refers to a shape in which no property is seen, and specifically corresponds to the shape of the concave portion 13 and the flat surface 14 shown in FIG.
On the other hand, examples of the “regular shape” other than the “irregular shape” include a circle, an ellipse, and a polygon. In this specification, a “polygon” is a figure in which a diagonal line can be drawn inside (without protruding outside), and the sum of interior angles is 180 × n (degrees) (n is a natural number) Refers to the figure enclosed by the straight line. The polygon includes a polygon having a rounded corner.

Further, in the present invention, the determination as to whether or not an “amorphous” concave portion or flat surface is present on the surface (α) of the resin layer is performed from the surface (α) side of the resin layer or the flat surface of the observation target. In principle, the shape of the recess is determined by visual observation or observation with a digital microscope (magnification: 30 to 100 times).
When a digital microscope is used, the focal point is moved in order from the top of the surface (α) in FIG. It is appropriate to observe as
When the focus cannot be determined by the above method, a light-transmitting adherend having a smooth surface on the surface (α) of the resin layer is stuck with a squeegee so as not to apply a load as much as possible, The determination may be made by observing the surface (α) of the resin layer through the translucent adherend using a microscope and confirming whether or not the concave portion and the flat surface exist.

However, an area (D) arbitrarily selected on the surface (α) and surrounded by a rectangle of 8 mm × 10 mm is selected from 1 to 10 areas, and a concave portion or flat area existing in each selected area (D) is selected. The shape of the surface may be determined by visual observation from the surface (α) side or by observation with a digital microscope (magnification: 30 to 100 times). That is, if an irregular concave portion or flat surface exists in any of the selected regions, it can be regarded as “an irregular concave portion or flat surface exists on the surface (α)”. Similarly, if there are a plurality of irregular concave portions or flat surfaces in any of the selected regions, it can be regarded as “a plurality of irregular concave portions or flat surfaces exist on the surface (α)”. .
When observing the region (D), the entire surface of the region (D) selected at a low magnification may be observed at a time using a digital microscope.
Further, by using a digital microscope at high magnification, it may be observed the selected area (D), because of the observed at high magnification, the area (D) is larger than the imaging area of the digital microscope May be. In such a case, using the image connection function of the digital microscope, a plurality of adjacent images are obtained by photographing arbitrarily selected mutually adjacent regions, and the plurality of images are connected to form a connected image. A portion surrounded by a rectangle of 8 mm × 10 mm arbitrarily selected from the connected image may be used as the region (D) for the above determination.
In the following description, in order to determine whether or not a certain requirement is satisfied, even when observing the selected area using a digital microscope, it may be determined from the connected image as described above. .

In the description of the present specification, examples of the digital microscope used when observing various shapes include, for example, product names “Digital Microscope VHX-1000” and “Digital Microscope VHX-5000” manufactured by Keyence Corporation. No.
When observing various shapes, a method of directly observing the surface (α) at the above magnification with a digital microscope may be used. A method of visually observing the shapes of the concave portion and the flat portion may be used.

Further, it is preferable that the shape of the irregular concave portion present on the surface (α) can be visually recognized from the surface (α) side.
Similarly, it is preferable that the shape of the irregular flat surface existing on the surface (α) can be visually recognized from the surface (α) side.
In addition, as shown in FIG. 1C or 1D, in the pressure-sensitive adhesive sheets 2a and 2b in which the release material 22 is laminated on the surface (α) 12a of the resin layer 12, when the release material 22 is removed. The exposed surface (α) is visually observed.

In one embodiment of the present invention, the surface (α) may have a regular concave portion together with the irregular concave portion 13 as shown in FIG.
However, the proportion of the area occupied by the irregular recesses present on the surface (α) with respect to 100% of the total area of the recesses present on the surface (α) is preferably 80 to 100%, more preferably 90 to 100%. More preferably, it is 95 to 100%, and still more preferably 100%.

Similarly, in one embodiment of the present invention, the surface (α) may have a regular flat surface together with the irregular flat surface 14 as shown in FIG.
However, the ratio of the area occupied by the irregular flat surface existing on the surface (α) with respect to the total area 100% of the flat surface existing on the surface (α) is preferably 80 to 100%, more preferably 90 to 100%. %, more preferably 95 to 100%, even more preferably 100%.

The “area ratio occupied by the concave portion or the flat surface” is obtained by acquiring an image of the surface (α) using a digital microscope (magnification: 30 to 100 times) and performing image processing (binary Process).
Also, an arbitrarily selected area (D) of 8 mm × 10 mm on the surface (α) is selected from 1 to 10 areas, and an image of the area is determined using a digital microscope (magnification: 30 to 100 times). The value of the “area ratio occupied by the concave portion or the flat surface” of each region is calculated from the image, and the average of the values of the selected 1 to 10 regions is calculated as the surface (α) of the resin layer of the target pressure-sensitive adhesive sheet. ) Can be regarded as the “area ratio occupied by the concave portion or the flat surface”.
The ratio of the area occupied by the flat surface existing on the surface (α) is preferably 50 to 90%, more preferably 55 to 80%, and still more preferably 60 to 70%.

  In one embodiment of the present invention, from the viewpoint of obtaining a pressure-sensitive adhesive sheet in which various properties such as air bleeding and pressure-sensitive properties are improved in a well-balanced manner, the shape of the concave portion and the flat surface existing on the surface (α) of the resin layer is constant. It is preferable not to have a shape which becomes a repeating unit.

Further, in one embodiment of the present invention, from the viewpoint of obtaining a pressure-sensitive adhesive sheet in which various properties such as air bleeding and pressure-sensitive properties are improved in a well-balanced manner, a plurality of concave portions are present on the surface (α) of the resin layer. It is preferable that the position where the concave portion exists has no periodicity. In addition, from the same viewpoint, it is preferable that a plurality of flat surfaces exist on the surface (α) of the resin layer, and the positions where the plurality of flat surfaces exist do not have periodicity.
In the present invention, "the position where a plurality of concave portions or flat surfaces exist does not have periodicity" means that the positions where the plurality of concave portions or flat surfaces exist on the surface (α) of the resin layer have the same repetition. It means that the pattern has no pattern and is irregular (random).

  In addition, it is determined whether or not “the shape of the concave portion and the flat surface does not have a shape that is a certain repeating unit”, and “the positions where the plurality of concave portions or the flat surface exist do not have periodicity”. The determination as to whether or not it is possible can be made by the same method as the above-described method for determining whether or not an irregular recess or flat surface exists on the surface (α) of the resin layer.

  Hereinafter, specific requirements regarding the concave portion and the flat surface existing on the surface (α) will be described.

<Specific requirements for recesses on surface (α)>
In one embodiment of the present invention, it is preferable that one or more irregular recesses are present in a region (Q) arbitrarily selected on the surface (α) of the resin layer and surrounded by a square with a side of 1 mm. More preferably, there are a plurality of irregular shaped recesses.
The presence of one or more irregular recesses in the above-mentioned region (Q) makes it possible to obtain a pressure-sensitive adhesive sheet having various properties such as air bleeding property and pressure-sensitive adhesive property improved in a well-balanced manner.

In one embodiment of the present invention, the concave portion 13 present on the surface (α) 12a of the resin layer 12 preferably has a maximum height difference of 0.5 μm or more.
The “recess” defined here refers to a recess having a maximum height difference of 0.5 μm or more, and a portion having a height difference of 0.5 μm or more may be present in any part of the recess. It is not necessary to have a height difference of 0.5 μm or more over the entire region of.

FIG. 3 is a schematic cross-sectional view of the resin layer of the pressure-sensitive adhesive sheet of the present invention, showing an example of the shape of the surface (α) side of the resin layer.
As in the concave portion 13 shown in FIG. 3A, the shape of a normal concave portion has two peak portions (M ₁ ) and (M ₂ ) and a valley portion (N). In the present invention, the “maximum height difference” of the concave portion refers to the highest position (m) of the two peak portions (M ₁ ) and (M ₂ ) in the thickness direction of the resin layer 12 (FIG. ) Means the length of the difference (h) between the peak (M ₁ ) maximum point and the lowest position (n) (the minimum point of the valley (N) in FIG. 3A).
In the case of FIG. 3B, a concave portion 131 having two peaks (M ₁₁ ) and (M ₁₂ ) and a valley (N ₁ ), two peaks (M ₁₂ ), (M ₁₃ ) and a concave portion 132 having a valley (N ₂ ). In this case, the length of the difference (h ₁ ) between the maximum point of the peak (M ₁₁ ) and the minimum point of the valley (N ₁ ) represents the maximum height difference of the concave portion 131, and the maximum of the peak (M ₁₃ ) The length of the difference (h ₂ ) between the point and the minimum point of the valley portion (N ₂ ) represents the maximum height difference of the concave portion 132.

  As the maximum height difference of one concave portion, from the viewpoint of improving the air bleeding property of the pressure-sensitive adhesive sheet, maintaining a good appearance of the pressure-sensitive adhesive sheet, and from the viewpoint of the shape stability of the pressure-sensitive adhesive sheet, more preferably 1.0 μm or more It is not more than the thickness of the resin layer, more preferably not less than 3.0 μm and not more than the thickness of the resin layer, and still more preferably not less than 5.0 μm and not more than the thickness of the resin layer.

In addition, the average value of the width of the concave portion is preferably 1 to 500 μm, more preferably 3 to 400 μm, from the viewpoint of improving the air bleeding property of the pressure-sensitive adhesive sheet and improving the pressure-sensitive adhesiveness of the pressure-sensitive adhesive sheet. Preferably it is 5-300 μm.
In the present invention, the width of the concave portion means the distance between the maximum points of the two peak portions, and in the concave portion 13 shown in FIG. 3A, the peak portion (M ₁ ) and the peak portion (M ₂ ). Further, in the concave portion 131 shown in FIG. 3 (b) refers to the distance _{L 1} between the peak portions _{(M 11)} and the peak portions _{(M 12),} in the recess 132, the peak portions _{(M 13)} and the mountain It refers to the distance _{L 2} between the portion _{(M 12).}
Further, when the pressure-sensitive adhesive sheet of the present invention is viewed in a plan view (when viewed from directly above), when the concave portion has a long side and a short side, the short side is referred to as a width.

  The ratio of the maximum height difference and the average value of the one concave portion [the maximum height difference / the average value of the width] (in the concave portion 13 shown in FIG. 3A, indicates “h / L”) Is preferably from 1/500 to 100/1, more preferably from 3/400 to 70/3, and still more preferably from the viewpoint of improving the air release property of the pressure-sensitive adhesive sheet and improving the pressure-sensitive adhesiveness of the pressure-sensitive adhesive sheet. 1/60 to 10/1.

<Specific requirements for flat surface existing on surface (α)>
In one embodiment of the present invention, a flat surface (f1) having a width capable of selecting a region surrounded by a circle having a diameter of at least 100 μm (preferably 150 μm, more preferably 200 μm) on the surface (α) of the resin layer. ) Is preferably present, and more preferably, a plurality of the flat surfaces (f1) exist.
The presence of the flat surface (f1) on the surface (α) provides a sufficient bonding portion with the adherend on the surface (α), so that the adhesion to the adherend can be improved. An adhesive sheet having high adhesive strength can be obtained.
In the above embodiment of the present invention, at least one flat surface (f1) exists in an arbitrarily selected region (D) of 8 mm × 10 mm on the surface (α) of the resin layer. Is preferable, and it is more preferable that a plurality of the flat surfaces (f1) exist.
In the above-described embodiment, all the flat surfaces existing on the surface (α) or the region (D) of the resin layer do not need to correspond to the flat surface (f1), and the surface (α) or the region ( The flat surface existing in D) may include a flat surface (f1).

In another embodiment of the present invention, a flat surface having an area of 0.2 mm ² or more (preferably 0.3 mm ² or more, more preferably 0.4 mm ² or more) is provided on the surface (α) of the resin layer. It is preferable that one or more (f2) exist, and it is more preferable that a plurality of the flat surfaces (f2) exist.
The presence of the flat surface (f2) on the surface (α) provides a sufficient bonding portion with the adherend on the surface (α), so that the adhesion to the adherend can be improved. An adhesive sheet having high adhesive strength can be obtained.
In the above aspect of the present invention, it is preferable that at least one flat surface (f2) exists in an arbitrarily selected area (D) of 8 mm × 10 mm on the surface (α) of the resin layer. It is more preferable that a plurality of the flat surfaces (f2) exist.
Note that, in the above-described embodiment, all the flat surfaces existing on the surface (α) or the region (D) of the resin layer do not need to correspond to the flat surface (f2), and the surface (α) or the region ( The flat surface existing in D) may include a flat surface (f2).

  Also, the flat surface (f1) and the flat surface (f2) corresponding to both the flat surface (f1) and the arbitrarily selected region (D) of 8 mm × 10 mm on the surface (α) or the surface (α) of the resin layer. Preferably, one or more surfaces (f12) exist, and more preferably, a plurality of the flat surfaces (f12) exist.

  In the present invention, it is determined whether or not the flat surface (f1), (f2), or (f12) exists on the surface (α) or the region (D) according to the resin layer of the target pressure-sensitive adhesive sheet. Obtain an image obtained by observing a flat surface existing on the surface (α) or the area (D) using a digital microscope (magnification: 30 to 100 times), and use the image analysis software based on the image to obtain a diameter. It may be determined whether a region surrounded by a 100 μm circle can be selected, or the area of a flat surface may be calculated.

In one embodiment of the present invention, in an arbitrarily selected area (D) of 8 mm × 10 mm on the surface (α) of the resin layer, the total area of the concave portions existing in the area (D) is 100%. , 70 to 99.99% (more preferably 85 to 99.99%).
The presence of such a continuity of the concave portion can provide a pressure-sensitive adhesive sheet with further improved air bleeding properties.

[Requirements for cross section (P1)]
The pressure-sensitive adhesive sheet of the present invention arbitrarily selects a region (P) surrounded by a square with a side of 5 mm on the surface (α) of the resin layer, passes through each of two diagonal lines of the square, and passes through the surface (α). A plurality of recesses satisfying the following requirement (I) in at least one cross section (P1) of the two cross sections of the pressure-sensitive adhesive sheet obtained by cutting the region (P) with a plane perpendicular to the following: There is a flat portion satisfying (II).
-Requirement (I): On the surface (α) side of the cross section (P1), there are a plurality of concave portions having a maximum height difference of 40% or more of the total thickness of the resin layer and different shapes of cut portions from each other. .
-Requirement (II): on the surface (α) side of the cross section (P1), which corresponds to the cut portion of the flat surface existing in the region (P), and was in contact with the resin layer of the base material or the release material. There is a flat part substantially parallel to the surface.

First, with reference to FIG. 4, a flow until the above-mentioned “two cross sections of the pressure-sensitive adhesive sheet” is obtained will be described.
FIG. 4 is a diagram for explaining a method for obtaining “two cross sections of the pressure-sensitive adhesive sheet” defined in the present invention, and is a perspective view of the pressure-sensitive adhesive sheet of one embodiment of the present invention. FIG. 4 shows, as an example, a perspective view of a pressure-sensitive adhesive sheet 11a having the same configuration as the pressure-sensitive adhesive sheet 1a shown in FIG. Are omitted.

First, an area (P) surrounded by a square 50 mm on a side of 5 mm is arbitrarily selected on the surface (α) 12 a of the resin layer 12. At this time, there is no restriction on the position (P) to be selected on the surface (α) 12a, the orientation of the square 50, and the like.
Then, the adhesion when the region (P) is cut on a plane that passes through each of the two diagonal lines 51 and 52 of the square 50 forming the region (P) and is perpendicular to the surface (α) 12a. Consider two cross sections 61, 62 of the sheet.
In other words, when the region (P) is cut along a plane perpendicular to the surface (α) 12a along the thickness direction A so as to pass through the diagonal line 51, the cross section 61 of the adhesive sheet becomes can get.
On the other hand, when the region (P) is cut along the diagonal line 52 along the thickness direction A and perpendicular to the surface (α) 12a, the cross section 62 of the adhesive sheet is obtained. Can be

In the present invention, for the two cross sections 61 and 62 of the pressure-sensitive adhesive sheet obtained in this way, the cross section in which a plurality of concave portions satisfying the above requirement (I) and a flat portion satisfying the above requirement (II) exists is referred to as “ Cross section (P1) ".
That is, in the present invention, at least one of the cross sections 61 and 62 needs to be a cross section (P1) in which a plurality of concave portions satisfying the requirement (I) and a flat portion satisfying the requirement (II) exist. .
Note that in one embodiment of the present invention, each of the two cross sections 61 and 62 preferably corresponds to the cross section (P1).

  In the present invention, it is determined whether or not the two cross sections 61 and 62 correspond to a cross section (P1) in which a plurality of concave portions satisfying the requirement (I) and a flat portion satisfying the requirement (II) exist. Whether or not the cross section (P1) satisfies various requirements described later is determined from an image obtained by using a scanning electron microscope (magnification: 100 to 1000 times) of the target cross section.

FIG. 5 is an example of a schematic diagram of a cross section (P1) defined by the present invention.
As shown in FIG. 5, the cross section (P1) 60 obtained by the above method has at least a plurality of recesses 13a and a flat portion 14a on the surface (α) 12a side of the cross section (P1) 60. .
In addition, as shown in FIG. 5, the projection 15a may be present on the surface (α) 12a side of the cross section (P1) 60.

In the cross section (P1) 60, as described in the requirement (I), the surface (α) 12a side of the cross section has a maximum height difference of 40% or more of the total thickness of the resin layer 12, and There are a plurality of recesses 13a having different shapes.
The concave portion 13a having the maximum height difference of 40% or more of the total thickness of the resin layer 12 is a portion which plays a role as an air discharge passage which greatly affects the air bleeding property of the adhesive sheet.
Since the shapes of the cut portions of the plurality of recesses 13a are different from each other, regardless of whether the adhesive sheet is attached or not, when a force having a certain direction is applied to the adhesive sheet, all the recesses have the same shape. , And the situation where the groove serving as the air discharge passage disappears can be prevented. As a result, it is possible to obtain a pressure-sensitive adhesive sheet having extremely excellent air bleeding properties.

Further, from the above viewpoint, in one embodiment of the present invention, in the cross section (P1) 60, among the plurality of recesses 13a existing on the surface (α) 12a side defined by the requirement (I), the shape of the cut portion is different. It is preferable to include a recess having an irregular shape.
Here, the “indefinite form” has the same meaning as described above.

In the present invention, the determination of “whether or not a recess having a maximum height difference of 40% or more of the total thickness of the resin layer 12” is determined, “whether or not the shapes of the cut portions of the plurality of recesses are different from each other”, and The determination of “whether or not the shape of the cut portion corresponds to a concave portion having an irregular shape” is determined from an image obtained by using the scanning electron microscope to obtain the cross section (P1) 60 as described above.
In the above, the determination of “whether or not the shapes of the cut portions of the plurality of concave portions are different from each other” may be made by, for example, superimposing the shapes of the cut portions of the two concave portions as targets shown in the image. If the coincident portion is less than 90% of the whole, it may be determined that “the two concave portions have different shapes of the cut portions”.

In the cross section (P1) 60, as described in the requirement (II), a cut portion of the flat surface 14 existing in a region (P) shown in FIG. Correspondingly, there is a flat portion 14a substantially parallel to the surface of the base material or the release material that is in contact with the resin layer 12.
The flat portion 14a corresponds to a cut surface of the flat surface 14 existing on the surface (α), and in the cross section (P1) 60, corresponds to a portion substantially parallel to the surface of the base material or the release material.
That is, cross (P1) 60 Oite shown in FIG. 5, the straight line e _alpha passing through the flat portion 14a, which is substantially parallel to the straight line e _beta through the surface of the substrate 11 in contact with the resin layer 12. Therefore, the flat portion 14a, such as shown in FIG. 4, is distinguished from the formed convex portion 15a as swell upward with respect to the straight line e _alpha.

  The term “substantially parallel” in the present invention refers to a straight line passing through the flat portion 14 a existing on the surface (α) side of the cross section (P 1) and a straight line passing through the surface of the base material or the release material in contact with the resin layer. Not only when the angle is 0 degrees, but also when the angle has a slight inclination that can be regarded as substantially parallel (for example, when the angle is 5 degrees or less, preferably 2 degrees or less). Case).

In addition, from the viewpoint of obtaining a pressure-sensitive adhesive sheet having a good balance between air bleedability and pressure-sensitive properties, in the cross-section (P1) 60, the flat portion 14a has a plurality of flat portions 14a on the surface (α) 12a side of the cross-section (P1) 60. It is preferable that the plurality of flat portions 14a present on the surface (α) 12a side have no periodicity.
Note that “the positions of the flat portions have no periodicity” means that the positions where the plurality of flat portions are present do not have the same repeating pattern and are irregular (random).

In the cross section (P1) 60, when there are a plurality of flat portions 14a on the surface (α) 12a side of the cross section (P1) 60, the plurality of flat portions 14a satisfy the requirement (II). Therefore, it can be said that the distances of the plurality of flat portions 14a existing on the surface (α) 12a side to the base material or the release material are the same.
In the present invention, "distance of each of the plurality of flat portions to the base material or the release material is the same" means that the difference in the distance between the target two flat portions and the base material or the release material is It includes a range of less than 5% (preferably less than 2%) with respect to the average value of the distance.

Furthermore, from the viewpoint of obtaining a pressure-sensitive adhesive sheet having improved air bleeding property and pressure-sensitive adhesive property, it is preferable that at least one of the following requirements (Ia) and (IIa) is satisfied. It is more preferable to satisfy the following.
Requirement (Ia): In the cross section (P1) 60, the width of the concave portion 13a existing on the surface (α) with respect to the horizontal width (E _α ) 100 of the resin layer 12 on the surface (α) 12a side. The ratio of the total is 10 to 90.
Requirement (IIa): In the cross section (P1) 60, the flat portion 14a existing on the surface (α) occupies the horizontal width (E _α ) 100 of the resin layer 12 on the surface (α) 12a side. The ratio is 10-90.

The “horizontal width (E _α ) of the resin layer on the surface (α) side” defined by the requirements (Ia) and (IIa) is a length indicated by E _α in FIG. For example, if the shape of the selected cross section (P1) 60 is a rectangle, it corresponds to the horizontal length of the rectangle.

The ratio occupied by the total width of the concave portion 13a present on the surface (α) 12a, which is defined by the requirement (Ia), is 10 to 90, preferably 20 to 80, more preferably 25 to 70, and furthermore Preferably it is 30-60.
As the ratio of the total width of the recesses 13a increases, the air bleeding property improves, and as the ratio decreases, the ratio of the flat portion 14a increases, so that the adhesive property improves.
As described above, in the present invention, the “width of the concave portion” refers to the distance L between the _two peak portions (M ₁ ) and the peak portions (M ₂ ) as shown in FIG. . Therefore, the “width of the concave portion” is a length including a part of the convex portion 15a. Therefore, when the convex portion 15a exists on the surface (α), the width is defined by the requirement (Ia). The sum of the ratio and the ratio specified in the requirement (IIa) does not become “100”, which is the same as the horizontal width (E _α ).

The ratio occupied by the flat portion existing on the surface (α), which is defined by the requirement (IIa), is 10 to 90, preferably 20 to 80, more preferably 25 to 70, and still more preferably 30 to 60. It is.
As the ratio occupied by the flat portion increases, the adhesive property improves, and as the ratio decreases, the ratio occupied by the concave portion increases, so that the air bleeding property improves.

In one embodiment of the present invention, in the cross section described above, from the viewpoint of forming a plurality of concave portions specified by the requirement (I) and a pressure-sensitive adhesive sheet having a flat portion satisfying the requirement (II), the concave portion is It is preferably not formed using a release material having an embossed pattern.
The “recess formed using a release material having an embossed pattern” includes, for example, the following, and is distinguished from the recess of the above-described embodiment.
A concave portion formed by pressing a release sheet having an embossed pattern against a flat surface of an adhesive layer formed from an adhesive composition and transferring the embossed pattern.
-Using a release sheet having an embossed pattern on the release-treated surface, applying an adhesive composition to the release-treated surface to form an adhesive layer, and then removing the release sheet, the adhesive layer The recess that appears on the surface of
Such a concave portion causes a number of inconveniences as listed as the problems relating to the pressure-sensitive adhesive sheet described in Patent Document 1.

In one embodiment of the present invention, the concave portion is formed by self-forming the resin layer from the viewpoint of forming a pressure-sensitive adhesive sheet having a concave portion and a flat surface satisfying the above requirements on the surface (α) of the resin layer. It is preferable that
In the present invention, "self-formation" means a phenomenon in which a resin layer autonomously forms a disordered shape in the process of autonomous formation. It means a phenomenon in which a dried coating film is dried to form a disordered shape naturally in the process of autonomously forming a resin layer.
The shape of the concave portion formed by the self-formation of the resin layer in this manner can be adjusted to some extent by adjusting the drying conditions and the types and contents of the components in the composition that is the material for forming the resin layer. Although possible, it can be said that unlike a groove formed by transferring an embossed pattern, it is practically impossible to reproduce a completely identical shape. Therefore, it can be said that the recess formed by the self-formation of the resin layer is irregular.
In addition, the formation of the irregular concave portion also makes the shape of the flat surface irregular.

The process of forming the concave portion formed by the self-formation of the resin layer is considered as follows.
First, at the time of forming a coating film composed of a composition to be a resin layer forming material, in a step of drying the coating film, shrinkage stress is generated inside the coating film, and at a portion where the bonding strength of the resin is weakened. Cracks occur in the coating. Then, it is considered that the concave portion is formed on the surface (α) of the resin layer by the resin around the crack portion flowing into the space temporarily generated by the crack.
After forming two layers of coatings with different resin contents, by simultaneously drying the two layers of coating, a shrinkage stress difference occurs inside the coating when drying, resulting in cracking of the coating. It will be easier.

From the viewpoint of facilitating the formation of the concave portion, it is preferable to adjust the following items as appropriate. It is considered that the factors due to these factors act in combination to facilitate formation of the concave portion. Incidentally, preferable aspects of each item for facilitating the formation of the concave portion are as described in the corresponding items described later.
The type, constituent monomer, molecular weight, and content of the resin contained in the composition that is the material for forming the coating film.
-The type of the crosslinking agent and the type of the solvent contained in the composition which is the material for forming the coating film.
-Viscosity and solid content concentration of a composition which is a material for forming a coating film.
The thickness of the coating film to be formed; (In the case of multiple layers, the thickness of each coating film)
-The drying temperature and drying time of the formed coating film.

In the formation of a pressure-sensitive adhesive layer of a general pressure-sensitive adhesive sheet, the above items are often set appropriately for the purpose of forming a pressure-sensitive adhesive layer having a flat surface.
On the other hand, in the present invention, the above items are set so that a concave portion that can contribute to the improvement of the air bleeding property of the pressure-sensitive adhesive sheet is intentionally formed. Are completely different.

The above items are preferably set as appropriate in consideration of the fluidity of the resin contained in the coating film to be formed.
For example, if the composition contains fine particles, by adjusting the viscosity of the coating film composed of the composition containing a large amount of fine particles to an appropriate range, while maintaining the predetermined fluidity of the fine particles in the coating film, Mixing with other coating films (coating films containing a large amount of resin) can be appropriately suppressed. Such adjustment tends to cause cracks in the horizontal direction in the coating film containing a large amount of resin and to easily form concave portions.
As a result, the proportion of the recesses formed on the surface (α) can be increased, and the proportion of the recesses connected to each other can be increased, whereby a pressure-sensitive adhesive sheet having more excellent air bleeding properties can be obtained.

Among the above items, it is preferable to appropriately adjust the type, constituent monomer, molecular weight, and content of the resin so that the resin contained in the coating film containing a large amount of resin has appropriate viscoelasticity.
That is, by appropriately setting the hardness of the coating film (hardness determined by factors such as the viscoelasticity of the resin and the viscosity of the coating solution), the shrinkage stress of the resin portion (X) is increased, and the concave portion is easily formed. Become. The higher the hardness of the coating film, the higher the shrinkage stress and the more likely it is to form a concave portion. If the elasticity of the resin is too high, the adhesive strength of the resin layer formed from the coating film tends to decrease. In consideration of this point, it is preferable that the viscoelasticity of the resin is appropriately adjusted.
In addition, when fine particles are contained in the composition or the coating film, by appropriately adjusting the dispersion state of the fine particles, the degree of swelling of the resin layer due to the fine particles and the self-forming force of the concave portion are adjusted, and as a result, It is considered that a concave portion can be easily formed on the surface (α) and can be adjusted.

Further, it is preferable to appropriately set the above items in consideration of the crosslinking speed of the formed coating film (or the composition as a forming material).
That is, if the crosslinking speed of the coating film is too high, the coating film may be cured before the concave portion is formed. It also affects the size of cracks in the coating.
The crosslinking speed of the coating film can be adjusted by appropriately setting the type of the crosslinking agent and the type of the solvent in the composition as the forming material, and the drying time and the drying temperature of the coating film.

In the case where the resin layer is a layer including a resin portion (X) containing a resin and a particle portion (Y) made of fine particles, the resin layer formed by the above-described self-formation has a structure shown in FIG. As shown in (d) and FIG. 5, the particle portion (Y) is such that the proportion occupied by the particle portion (Y) is smaller in the portion where the concave portion exists on the surface (α) than in other portions. Tends to be distributed.
This is because in the process of self-forming the resin layer, when a concave portion is formed on the surface (α) of the resin layer, the fine particles existing at the position where the concave portion is formed move. It is thought that it became distribution.

As an aspect of the distribution of the particle portion (Y) in the resin layer formed by such self-formation, an aspect as shown in FIG. 5 is given.
That is, as shown in FIG. 5, in the cross section 60, the distribution of the particle portions (Y) contained in the resin layer 12 in the horizontal direction is non-uniform, and the concave portions 13a existing on the surface (α) 12a are formed. In contrast, the distribution of the particle portion (Y) in the region (s1) located below the concave portion 13a in the thickness direction is such that the flat portion is formed on the surface (α) 12a at the same horizontal position as the region (s1). It is preferable that the number is smaller than that of the region (s2).
Such uneven distribution of the particle portion (Y) is peculiar to the resin layer formed by self-formation.

  Hereinafter, each configuration used in the present invention will be described.

〔Base material〕
The base material used in the present invention is not particularly limited, and examples thereof include a paper base material, a resin film or sheet, a base material obtained by laminating a paper base material with a resin, and the use of the pressure-sensitive adhesive sheet of one embodiment of the present invention. Can be appropriately selected according to the conditions.
Examples of the paper constituting the paper base include thin paper, medium quality paper, high quality paper, impregnated paper, coated paper, art paper, sulfuric acid paper, glassine paper and the like.
Examples of the resin constituting the resin film or sheet include polyolefin resins such as polyethylene and polypropylene; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer and ethylene-vinyl alcohol copolymer. Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic-modified polyurethane; polymethylpentene; Polysulfone; polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; Polyamide resins, acrylic resins, fluorine-based resins.
Examples of the substrate obtained by laminating a paper substrate with a resin include a laminated paper obtained by laminating the above-mentioned paper substrate with a thermoplastic resin such as polyethylene.

Among these substrates, a resin film or sheet is preferable, a film or sheet made of a polyester resin is more preferable, and a film or sheet made of polyethylene terephthalate (PET) is more preferable.
When the pressure-sensitive adhesive sheet of the present invention is used for applications requiring heat resistance, a film or sheet composed of a resin selected from polyethylene naphthalate and a polyimide resin is preferable, and applications requiring weather resistance are preferred. In the case where it is used, a film or sheet composed of a resin selected from polyvinyl chloride, polyvinylidene chloride, acrylic resin, and fluororesin is preferable.

The thickness of the substrate is appropriately set according to the use of the pressure-sensitive adhesive sheet of the present invention, but from the viewpoint of handleability and economy, preferably 5 to 1000 μm, more preferably 10 to 500 μm, and still more preferably 12 to 500 μm. It is 250 μm, more preferably 15 to 150 μm.
Note that the base material may further contain various additives such as an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, and a coloring agent.

Further, the base material used in the present invention is preferably a non-breathable base material from the viewpoint of improving the blister resistance of the obtained pressure-sensitive adhesive sheet. Substrates having a layer are preferred.
Examples of the metal contained in the metal layer include metals having a metallic luster such as aluminum, tin, chromium, and titanium.
As a method for forming the metal layer, for example, a method in which the metal is deposited by a PVD method such as vacuum deposition, sputtering, or ion plating, or a metal foil made of the metal is attached using a general adhesive. Although the method etc. are mentioned, the method of vapor-depositing the said metal by PVD method is preferable.

Further, when a resin film or sheet is used as the base material, the surface of the resin film or sheet is oxidized or roughened from the viewpoint of improving the adhesion with the resin layer laminated on the resin film or sheet. Surface treatment by a method or the like, or primer treatment may be performed.
Examples of the oxidation method include a corona discharge treatment, a plasma discharge treatment, a chromic acid treatment (wet method), a hot air treatment, ozone, and an ultraviolet irradiation treatment. And the like.

(Release material)
As the release material used in the present invention, a release sheet that has been subjected to a double-sided release treatment, a release sheet that has been subjected to a single-sided release treatment, or the like is used.
Note that the release-treated surface is preferably a release material that does not have an uneven shape and is flat (for example, a release material that has not been embossed).
Examples of the base material for the release material include the above-described paper base material, a resin film or sheet, and a base material obtained by laminating a paper base material with a resin, which are used as the base material of the pressure-sensitive adhesive sheet of one embodiment of the present invention. Can be
Examples of the release agent include a rubber-based elastomer such as a silicone-based resin, an olefin-based resin, an isoprene-based resin, and a butadiene-based resin, a long-chain alkyl-based resin, an alkyd-based resin, and a fluorine-based resin.
The thickness of the release material is not particularly limited, but is preferably 10 to 200 μm, more preferably 25 to 170 μm, and still more preferably 35 to 80 μm.

(Resin layer)
As shown in FIG. 1, the resin layer 12 of the pressure-sensitive adhesive sheet of the present invention preferably includes a resin portion (X) containing a resin and a particle portion (Y) made of fine particles.
The resin portion (X) indicates a portion containing components other than the fine particles contained in the resin layer. That is, not only the resin but also components other than the fine particles such as a tackifier, a crosslinking agent, and a general-purpose additive contained in the resin layer are included in the “resin portion (X)”.
On the other hand, the particle portion (Y) indicates a portion composed of fine particles contained in the resin layer.

By including the particle portion (Y) in the resin layer, the shape retention after sticking can be improved, and when the obtained pressure-sensitive adhesive sheet is used at a high temperature, the generation of blisters is effectively suppressed. be able to.
The configuration of the distribution of the resin portion (X) and the particle portion (Y) in the resin layer 12 may be a configuration in which the resin portion (X) and the particle portion (Y) are substantially evenly distributed. In particular, the configuration may be such that a portion mainly composed of the resin portion (X) and a portion mainly composed of the particle portion (Y) can be separated.

The resin layer of the pressure-sensitive adhesive sheet of the present invention preferably has a void portion (Z) in addition to the resin portion (X) and the particle portion (Y). By having the void portion (Z) in the resin layer, the blister resistance of the pressure-sensitive adhesive sheet can be improved.
The void portion (Z) includes voids existing between the fine particles, and voids existing in the secondary particles when the fine particles are secondary particles.
In the case where the resin layer has a multilayer structure, the resin portion (X) flows into the gap portion (Z) even if the gap portion (Z) is present during or immediately after the formation of the resin layer. In some cases, the voids disappear and the resin layer has no void portion (Z).
However, even when the void portion (Z) which has been present in the resin layer for a period of time disappears, the pressure-sensitive adhesive sheet according to one embodiment of the present invention has a concave portion on the surface (α) of the resin layer. Therefore, the air bleeding property is good, and since the resin layer has the particle portion (Y), the blister resistance is also excellent.

Further, the shear storage modulus at 100 ° C. of the resin layer of the pressure-sensitive adhesive sheet of the present invention is preferably 9.0 × 10 ³ Pa or more, more preferably, from the viewpoint of improving the air bleeding property and the blister resistance of the pressure-sensitive adhesive sheet. Is 1.0 × 10 ⁴ Pa or more, more preferably 2.0 × 10 ⁴ Pa or more.
In the present invention, the shear storage modulus at 100 ° C. of the resin layer is measured by measuring at a frequency of 1 Hz using a viscoelasticity measuring device (for example, a device name “DYNAMIC ANALYZER RDA II” manufactured by Rheometrics). Means the value.

  The thickness of the resin layer is preferably 1 to 300 μm, more preferably 5 to 150 μm, and still more preferably 10 to 75 μm.

  In the pressure-sensitive adhesive sheet of the present invention, at least the surface (α) of the resin layer on the side opposite to the side on which the base material or the release material is provided has tackiness, but the base material or the release material is provided. The surface (β) of the resin layer on the side may also have tackiness.

The adhesive strength on the surface (α) of the resin layer of the adhesive sheet of the present invention is preferably 0.5 N / 25 mm or more, more preferably 2.0 N / 25 mm or more, more preferably 3.0 N / 25 mm or more, and still more preferably. Is 4.0 N / 25 mm or more, more preferably 7.0 N / 25 mm or more.
When the surface (β) of the resin layer also has adhesiveness, the adhesive force on the surface (β) preferably belongs to the above range.
In addition, the value of the said adhesive force of an adhesive sheet means the value measured by the method as described in an Example.

<Multilayer structure of resin layer>
The resin layer in the present invention is composed of three or more layers having a resin layer obtained by laminating a layer (Xβ), a layer (Y1), and a layer (Xα) in this order on a base material or a release material. It is a multilayer structure to be formed.
As a resin layer having such a multilayer structure, a layer (Xβ) mainly containing a resin portion (X) from the side on which a base material or a release material is provided, such as the pressure-sensitive adhesive sheet 1a in FIG. A multilayer structure in which a layer (Y1) containing a particle portion (Y) and a layer (Xα) mainly containing a resin portion (X) are laminated in this order.
In the structure of the multilayer structure of the resin layer, the boundary between the two layers to be laminated cannot be determined, and the layers may be in a mixed state.
That is, in the resin layer 12 of the pressure-sensitive adhesive sheet 1a of FIG. 1, the boundary between the layer (Xβ) and the layer (Y1) and / or the boundary between the layer (Y1) and the layer (Xα) cannot be determined. , Or a mixed layer structure.

  Hereinafter, the configuration of the resin layer that is a multilayer structure will be described with reference to the resin layer 12 of the pressure-sensitive adhesive sheet 1a of FIG. explain.

The layer (Xβ) and the layer (Xα) are layers mainly including the resin portion (X), but may include the particle portion (Y). However, the content of the particle portion (Y) in the layer (Xβ) and the layer (Xα) is independently 15 mass% with respect to the total mass (100 mass%) of the layer (Xβ) or the layer (Xα). % And less than the content of the resin in the layer (Xβ) or the layer (Xα).
That is, the layer (Xβ) and the layer (Xα) are distinguished from the layer (Y1) in terms of the content of the particle portion (Y).
In addition, the layer (Xβ) and the layer (Xα) may further have the above-described void portion (Z) in addition to the resin portion (X) and the particle portion (Y).

The content of the resin portion (X) in the layer (Xβ) and the layer (Xα) is usually 85 mass% with respect to the total mass (100 mass%) of the layer (Xβ) or the layer (Xα) independently. %, Preferably 87 to 100% by mass, more preferably 90 to 100% by mass, still more preferably 95 to 100% by mass, and still more preferably 100% by mass.
The “content of the resin part (X)” refers to the resin, the tackifier, the crosslinking agent, and the general-purpose additive that constitute the resin part (X) contained in the layer (Xβ) or the layer (Xα). It means the total content of components other than fine particles such as an agent.

The content of the fine particles constituting the particle portion (Y) in the layer (Xβ) and the layer (Xα) is each independently based on the total mass (100% by mass) of the layer (Xβ) or the layer (Xα). , Less than 15% by mass, preferably 0 to 13% by mass, more preferably 0 to 10% by mass, still more preferably 0 to 5% by mass, and still more preferably 0% by mass.
In the present invention, the “content of fine particles in the layer (Xβ) and the layer (Xα)” refers to the total amount (100% by mass (100% by mass) of the resin composition that is the material for forming the layer (Xβ) or the layer (Xα) However, it can be regarded as the content of the fine particles in the excluding the diluting solvent))).

The content of the resin in the layer (Xα) is usually 30 to 100% by mass, preferably 40 to 100% by mass, more preferably 50 to 100% by mass based on the total mass (100% by mass) of the layer (Xα). %, More preferably 60 to 100% by mass.
On the other hand, the content of the resin in the layer (Xβ) is usually 50 to 100% by mass, preferably 65 to 100% by mass, more preferably 75 to 100% by mass based on the total mass (100% by mass) of the layer (Xβ). To 100% by mass, more preferably 85 to 100% by mass.
In the present invention, “the content of the resin in the layer (Xβ) and the layer (Xα)” refers to the total amount (100% by mass (100% by mass) of the resin composition that is the material forming the layer (Xβ) or the layer (Xα). However, it can be regarded as the content of the resin in (excluding the dilution solvent))).

The layer (Y1) is a layer including the resin portion (X) and the particle portion (Y), and may be a layer having a void portion (Z).
The content of the fine particles constituting the particle portion (Y) in the layer (Y1) is 15% by mass or more based on the total mass (100% by mass) of the layer (Y1), but is preferably 20 to 100%. %, More preferably 25 to 90% by mass, still more preferably 30 to 85% by mass, and still more preferably 35 to 80% by mass.

  The content of the resin in the layer (Y1) is generally 0 to 85% by mass, preferably 1 to 80% by mass, more preferably 5 to 75% by mass based on the total mass (100% by mass) of the layer (Y1). %, More preferably from 10 to 70% by mass, even more preferably from 20 to 65% by mass.

  In the present invention, the “content of the fine particles in the layer (Y1)” and the “content of the resin in the layer (Y1)” are the total amount (100 mass) of the composition that is the material for forming the layer (Y1). % (However, excluding the diluting solvent) can be regarded as the content of the fine particles or the resin in%.

In one embodiment of the present invention, the layer (Xα) is preferably a layer formed from a composition (xα) containing a resin and having a content of fine particles of less than 15% by mass.
Similarly, the layer (Xβ) is preferably a layer formed from the composition (xβ) containing a resin and having a content of fine particles of less than 15% by mass.
The layer (Y1) is a layer formed from the composition (y1) containing 15% by mass or more of fine particles.
In addition, preferable aspects (content components, content, and the like) of the composition (xα), the composition (xβ), and the composition (y1) are as described below.

<Resin part (X)>
The resin portion (X) constituting the resin layer is a portion containing components other than the fine particles contained in the resin layer, and is distinguished from the particle portion (Y) in that respect.
The resin portion (X) may contain a tackifier, a crosslinking agent, a general-purpose additive, and the like, together with the resin.

The content of the resin in the resin portion (X) is usually 30% by mass or more, preferably 40% by mass or more, more preferably 50% by mass or more, based on the total amount (100% by mass) of the resin portion (X). It is more preferably at least 55% by mass, still more preferably at least 60% by mass, still more preferably at least 70% by mass, and preferably at most 100% by mass, more preferably at most 99.9% by mass.
In the present invention, the value of the content of the resin in the resin composition serving as the material for forming the resin portion (X) can also be regarded as the “content of the resin in the resin portion (X)”.

The resin contained in the resin portion (X) preferably contains an adhesive resin from the viewpoint of exhibiting adhesiveness on the surface (α) of the formed resin layer.
In particular, as in the pressure-sensitive adhesive sheet 1a in FIG. 1 (a), the resin layer is formed in the order of the layer (Xβ), the layer (Y1), and the layer (Xα) from the side on which the base material or the release material is provided. From the above viewpoint, at least the layer (Xα) contains an adhesive resin. From the viewpoint of forming a double-sided pressure-sensitive adhesive sheet and improving the adhesion to a substrate, at least the layer (Xα) and the layer (Xβ) preferably contain a pressure-sensitive adhesive resin.

(Adhesive resin)
Examples of the adhesive resin include an acrylic resin, a urethane resin, a rubber resin, and a silicone resin.
Among these adhesive resins, it is preferable to include an acrylic resin from the viewpoint that adhesive properties and weather resistance are good and that a concave portion is easily formed on the surface (α) of the resin layer.
The content of the acrylic resin is preferably 25 to 100% by mass, more preferably 50 to 100% by mass, and still more preferably 70 to 100% by mass with respect to the total amount (100% by mass) of the resin contained in the resin portion (X). To 100% by mass, more preferably 80 to 100% by mass, even more preferably 100% by mass.

In addition, from the viewpoint of easily forming a concave portion on the surface (α) of the resin layer, the resin portion (X) preferably contains a resin having a functional group, and more preferably contains an acrylic resin having a functional group. .
In particular, as in the pressure-sensitive adhesive sheet 1a of FIG. In the case of a multilayer structure laminated by the above, at least the layer (Y1) preferably contains a resin having a functional group from the above viewpoint.
The functional group is a group serving as a starting point of crosslinking with a crosslinking agent, and examples thereof include a hydroxy group, a carboxy group, an epoxy group, an amino group, a cyano group, a keto group, and an alkoxysilyl group. preferable.

The resin portion (X) preferably further contains a crosslinking agent together with the resin having the functional group. In particular, when the resin layer has the above-mentioned multilayer structure, at least the layer (Y1) preferably contains a crosslinking agent together with the resin having the functional group.
Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent.

  Isocyanate-based crosslinking agents include, for example, aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; And a biuret form, an isocyanurate form, and an adduct of a reaction product of these compounds with low-molecular-weight active hydrogen-containing compounds (such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil); Is mentioned.

  Examples of the epoxy crosslinking agent include ethylene glycol glycidyl ether, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, Examples thereof include 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, and diglycidylamine.

  Examples of the aziridine-based crosslinking agent include diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropanetri-β-aziridinylpropionate, and tetramethylolmethanetri-β-aziridinyl. Propionate, toluene-2,4-bis (1-aziridinecarboxamide), triethylenemelamine, bisisophthaloyl-1- (2-methylaziridine), tris-1- (2-methylaziridine) phosphine, Trimethylolpropane tri-β- (2-methylaziridine) propionate and the like.

Examples of the metal chelate-based crosslinking agent include chelate compounds in which the metal atom is aluminum, zirconium, titanium, zinc, iron, tin, or the like. Chelating crosslinking agents are preferred.
Examples of the aluminum chelate-based crosslinking agent include diisopropoxyaluminum monooleyl acetoacetate, monoisopropoxyaluminum bisoleylacetoacetate, monoisopropoxyaluminum monooleate monoethylacetoacetate, diisopropoxyaluminum monolauryl acetoacetate, Isopropoxyaluminum monostearyl acetoacetate, diisopropoxyaluminum monoisostearyl acetoacetate, and the like.

In addition, you may use these crosslinking agents individually or in combination of 2 or more types.
Among these, from the viewpoint of easily forming a concave portion on the surface (α) of the resin layer, the resin portion (X) is at least one selected from a metal chelate-based crosslinking agent, an epoxy-based crosslinking agent, and an aziridine-based crosslinking agent. Is preferably contained, more preferably a metal chelate crosslinking agent is contained, and even more preferably an aluminum chelate crosslinking agent is contained.

  The content of the crosslinking agent in the resin part (X) is preferably 0.01 to 15 parts by weight, more preferably 0.1 to 15 parts by weight, based on 100 parts by weight of the functional group-containing resin contained in the resin part (X). The amount is from 10 to 10 parts by mass, more preferably from 0.3 to 7.0 parts by mass.

Further, as one embodiment of the present invention, from the viewpoint of easily forming a concave portion on the surface (α) of the resin layer, it is preferable that the resin portion (X) contains both a metal chelate-based crosslinking agent and an epoxy-based crosslinking agent. .
When the resin portion (X) contains both a metal chelate crosslinking agent and an epoxy crosslinking agent, from the above viewpoint, the content ratio of the metal chelate crosslinking agent to the epoxy crosslinking agent in the resin portion (X) [metal chelate crosslinking agent] [Crosslinking agent / epoxy crosslinking agent]], by mass ratio, preferably 10/90 to 99.5 / 0.5, more preferably 50/50 to 99.0 / 1.0, and still more preferably 65/35. ９８98.5 / 1.5, more preferably 75 / 25-98.0 / 2.0.

  The resin portion (X) preferably further contains a tackifier together with the adhesive resin from the viewpoint of further improving the adhesive properties of the surface (α). In particular, when the resin layer has the above-described multilayer structure, the layer (Xα) preferably contains an adhesive resin and a tackifier.

(Tackifier)
The tackifier used in the present invention is a component that assists in improving the adhesive strength of the adhesive resin, and refers to an oligomer having a mass average molecular weight (Mw) of usually less than 10,000 and is distinguished from the above-mentioned adhesive resin. Is what is done.
The weight average molecular weight (Mw) of the tackifier is preferably from 400 to 8000, more preferably from 5,000 to 5,000, more preferably from 800 to 3,500.

Examples of the tackifier include rosin resins such as rosin resin, rosin ester resin and rosin modified phenol resin; hydrogenated rosin resin obtained by hydrogenating these rosin resins; terpene resin, aromatic modified terpene resin, terpene phenol Terpene resins such as terpene resins; hydrogenated terpene resins obtained by hydrogenating these terpene resins; styrene obtained by copolymerizing styrene monomers such as α-methylstyrene or β-methylstyrene with aliphatic monomers. -Based resins; hydrogenated styrene-based resins obtained by hydrogenating these styrene-based resins; C5-based resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine and 1.3-pentadiene produced by thermal decomposition of petroleum naphtha Petroleum resin and hydrogenated petroleum resin of this C5 petroleum resin; indene, vinyl resin produced by pyrolysis of petroleum naphtha A C9 petroleum resin obtained by copolymerizing a C9 fraction such as toluene, and a hydrogenated petroleum resin obtained from the C9 petroleum resin.
The tackifiers used in the present invention may be used alone or in combination of two or more having different softening points and structures.

The softening point of the tackifier is preferably 80 ° C. or higher, more preferably 80 to 180 ° C., further preferably 83 to 170 ° C., and still more preferably 85 to 150 ° C.
In the present invention, the “softening point” of the tackifier means a value measured according to JIS K 2531.
When two or more kinds of tackifiers are used, the weighted average of the softening points of the plurality of tackifiers preferably falls within the above range.

  When the tackifier is contained in the resin portion (X), the content of the tackifier is preferably at least 1 part by mass, based on 100 parts by mass of the tacky resin contained in the resin portion (X). Preferably it is 1 to 200 parts by mass, more preferably 3 to 150 parts by mass, even more preferably 5 to 90 parts by mass.

In addition, the resin portion (X) may contain a general-purpose additive other than the above-mentioned crosslinking agent and tackifier.
Examples of general-purpose additives include antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction accelerators, and ultraviolet absorbers.
These general-purpose additives may be used alone or in combination of two or more.
When these general-purpose additives are contained, the content of each general-purpose additive is preferably 0.0001 to 60 parts by mass, more preferably 0.001 to 50 parts by mass, based on 100 parts by mass of the resin. .

The resin contained in the resin portion (X) may be used alone or in combination of two or more.
The material for forming the resin portion (X) of the resin layer of the pressure-sensitive adhesive sheet of the present invention is preferably a pressure-sensitive adhesive containing a pressure-sensitive adhesive resin having a functional group, and an acrylic resin (A) having a functional group (hereinafter referred to as “A”). Is more preferably an acrylic pressure-sensitive adhesive containing only an "acrylic resin (A)"), and an acrylic pressure-sensitive adhesive containing an acrylic resin (A) having a functional group and a crosslinking agent (B). Is more preferable.
The acrylic pressure-sensitive adhesive may be any of a solvent type and an emulsion type.
Hereinafter, the above-mentioned acrylic pressure-sensitive adhesive suitable for the resin portion (X) as a forming material will be described.

Examples of the acrylic resin (A) contained in the acrylic pressure-sensitive adhesive include a polymer having a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group, and a cyclic structure ( A polymer having a structural unit derived from (meth) acrylate is exemplified.
The mass average molecular weight (Mw) of the acrylic resin (A) is preferably from 50,000 to 1.5 million, more preferably from 150,000 to 1.3 million, further preferably from 250,000 to 1.1 million, and still more preferably from 350,000 to 90,000. It is ten thousand.

As the acrylic resin (A), a structural unit (a1) derived from an alkyl (meth) acrylate (a1 ′) having an alkyl group having 1 to 18 carbon atoms (hereinafter, also referred to as “monomer (a1 ′)”); And an acrylic copolymer (A1) having a structural unit (a2) derived from a functional group-containing monomer (a2 ′) (hereinafter also referred to as “monomer (a2 ′)”). More preferably, it is a combination (A1).
The content of the acrylic copolymer (A1) is preferably 50 to 100% by mass, more preferably 70 to 100%, based on the total amount (100% by mass) of the acrylic resin (A) in the acrylic pressure-sensitive adhesive. %, More preferably 80 to 100% by mass, even more preferably 90 to 100% by mass.
The mode of copolymerization of the acrylic copolymer (A1) is not particularly limited, and may be any of a block copolymer, a random copolymer, and a graft copolymer.

The number of carbon atoms of the alkyl group of the monomer (a1 ′) is more preferably 4 to 12, still more preferably 4 to 8, and even more preferably 4 to 6, from the viewpoint of improving adhesive properties.
Examples of the monomer (a1 ′) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and tridecyl ( (Meth) acrylate, stearyl (meth) acrylate and the like.
Among these, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferred, and butyl (meth) acrylate is more preferred.

  The content of the structural unit (a1) is preferably 50 to 99.5% by mass, more preferably 60 to 99% by mass, based on all the structural units (100% by mass) of the acrylic copolymer (A1). More preferably, it is 70 to 95% by mass, and still more preferably 80 to 93% by mass.

Examples of the monomer (a2 ′) include a hydroxy group-containing monomer, a carboxy group-containing monomer, an epoxy group-containing monomer, an amino group-containing monomer, a cyano group-containing monomer, a keto group-containing monomer, and an alkoxysilyl group-containing monomer. .
Among these, a carboxy group-containing monomer is more preferable.
Examples of the carboxy group-containing monomer include (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid, and (meth) acrylic acid is preferred.

  The content of the structural unit (a2) is preferably from 0.5 to 50% by mass, more preferably from 1 to 40% by mass, based on all the structural units (100% by mass) of the acrylic copolymer (A1). More preferably, it is 5 to 30% by mass, and still more preferably 7 to 20% by mass.

In addition, the acrylic copolymer (A1) may have a structural unit (a3) derived from another monomer (a3 ′) other than the monomers (a1 ′) and (a2 ′).
Examples of the other monomer (a3 ′) include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyl Examples thereof include (meth) acrylate having a cyclic structure such as oxyethyl (meth) acrylate and imide (meth) acrylate, vinyl acetate, acrylonitrile, and styrene.

The content of the structural unit (a3) is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, and still more preferably, based on all the structural units (100% by mass) of the acrylic copolymer (A1). Is 0 to 10% by mass, more preferably 0 to 5% by mass.
The above-mentioned monomers (a1 ′) to (a3 ′) may be used alone or in combination of two or more.

  The method for synthesizing the acrylic copolymer (A1) component is not particularly limited. For example, a raw material monomer is dissolved in a solvent, and solution polymerization is performed in the presence of a polymerization initiator, a chain transfer agent, and the like. It is produced by a method or a method of emulsion polymerization in an aqueous system using a raw material monomer in the presence of an emulsifier, a polymerization initiator, a chain transfer agent, a dispersant, and the like.

Examples of the cross-linking agent (B) contained in the acrylic pressure-sensitive adhesive include the above-mentioned cross-linking agents, but from the viewpoint of improving the adhesive properties and the viewpoint of easily forming a concave portion on the surface (α) of the resin layer. Preferably contains at least one selected from a metal chelate-based crosslinker, an epoxy-based crosslinker, and an aziridine-based crosslinker, more preferably contains a metal chelate-based crosslinker, and contains an aluminum chelate-based crosslinker. Is more preferred.
Further, in one embodiment of the present invention, from the viewpoint of improving the shape retention of a plurality of concave portions present on the surface (α) of the resin layer, the crosslinking agent (B) includes a metal chelate crosslinking agent and an epoxy crosslinking agent. It is preferable to include the agent together.

  The content of the crosslinking agent (B) is preferably 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the acrylic resin (A) in the acrylic pressure-sensitive adhesive. And more preferably 0.3 to 7.0 parts by mass.

  When a metal chelate crosslinking agent and an epoxy crosslinking agent are used in combination, the content ratio of the metal chelating crosslinking agent to the epoxy crosslinking agent [metal chelating crosslinking agent / epoxy crosslinking agent] is preferably a mass ratio, 10/90 to 99.5 / 0.5, more preferably 50/50 to 99.0 / 1.0, still more preferably 65/35 to 98.5 / 1.5, even more preferably 75/25 to 98.0 / 2.0.

  The acrylic pressure-sensitive adhesive used in one embodiment of the present invention may contain a general-purpose additive as long as the effects of the present invention are not impaired. Examples of the general-purpose additive include those described above, and the content of the general-purpose additive is also as described above.

  Further, the acrylic pressure-sensitive adhesive used in one embodiment of the present invention preferably further contains a tackifier from the viewpoint of further improving the pressure-sensitive adhesive properties of the surface (α). Examples of the tackifier include those described above, and the content of the tackifier is also as described above.

The acrylic pressure-sensitive adhesive used in one embodiment of the present invention includes a pressure-sensitive adhesive resin other than the acrylic resin (A) (for example, urethane-based resin, rubber-based resin, silicone-based resin, and the like) as long as the effects of the present invention are not impaired. ) May be contained.
The content of the acrylic resin (A) in the acrylic pressure-sensitive adhesive is preferably 50 to 100% by mass, more preferably 70% by mass, based on the total amount (100% by mass) of the pressure-sensitive adhesive resin contained in the acrylic pressure-sensitive adhesive. To 100% by mass, more preferably 80 to 100% by mass, even more preferably 100% by mass.

<Particle part (Y)>
The resin layer included in the pressure-sensitive adhesive sheet of one embodiment of the present invention preferably includes a particle portion (Y) including fine particles.
The average particle size of the fine particles is preferably 0.01 from the viewpoint of improving the air bleeding property and blister resistance of the pressure-sensitive adhesive sheet, and from the viewpoint of easily forming a concave portion and a flat surface on the surface (α) of the resin layer. To 100 µm, more preferably 0.05 to 25 µm, and still more preferably 0.1 to 10 µm.

The fine particles used in one embodiment of the present invention are not particularly limited, and include inorganic particles such as silica particles, metal oxide particles, barium sulfate, calcium carbonate, magnesium carbonate, glass beads, and smectite, and organic particles such as acrylic beads. No.
Among these fine particles, one or more selected from silica particles, metal oxide particles, and smectite are preferable, and silica particles are more preferable.

The silica particles used in one embodiment of the present invention may be either dry silica or wet silica.
Further, the silica particles used in one embodiment of the present invention are organically modified silica surface-modified with an organic compound having a reactive functional group, and inorganic modified silica surface-treated with an inorganic compound such as sodium aluminate or sodium hydroxide. And organic-inorganic modified silica surface-treated with these organic compounds and inorganic compounds, and organic-inorganic modified silica surface-treated with an organic-inorganic hybrid material such as a silane coupling agent.
In addition, these silica particles may be a mixture of two or more kinds.

The mass concentration of silica in the silica particles is preferably from 70 to 100% by mass, more preferably from 85 to 100% by mass, and still more preferably from 90 to 100% by mass, based on the total amount (100% by mass) of the silica particles. .
Further, the volume average secondary particle diameter of the silica particles used in one embodiment of the present invention is such that the pressure-sensitive adhesive sheet has improved air bleeding property and blister resistance, and has a concave portion and a flat surface on the surface (α) of the resin layer. From the viewpoint of easy formation, the thickness is preferably 0.5 to 10 μm, more preferably 1 to 8 μm, and still more preferably 1.5 to 5 μm.
In the present invention, the value of the volume average secondary particle size of the silica particles is a value obtained by measuring the particle size distribution by a Coulter counter method using a Multisizer-3 machine or the like.

  Examples of the metal oxide particles include, for example, particles made of a metal oxide selected from titanium oxide, alumina, boehmite, chromium oxide, nickel oxide, copper oxide, titanium oxide, zirconium oxide, indium oxide, zinc oxide, and composite oxides thereof. And sol particles composed of these metal oxides are also included.

  Examples of the smectite include montmorillonite, beidellite, hectorite, saponite, stevensite, nontronite, and sauconite.

The mass retention after heating the resin layer of the pressure-sensitive adhesive sheet of one embodiment of the present invention at 800 ° C. for 30 minutes is preferably 3 to 90% by mass, more preferably 5 to 80% by mass, and still more preferably 7 to 70% by mass. %, More preferably 9 to 60% by mass.
The mass retention can be regarded as indicating the content (% by mass) of the fine particles contained in the resin layer.
When the mass retention is 3% by mass or more, a pressure-sensitive adhesive sheet excellent in air bleeding property and blister resistance can be obtained. Further, during the production of the pressure-sensitive adhesive sheet of the present invention, a concave portion is easily formed on the surface (α) of the resin layer. On the other hand, when the mass retention is 90% by mass or less, the resin layer has high film strength, excellent water resistance and chemical resistance, and a flat surface is easily formed on the surface (α) of the resin layer.

(Production method of the pressure-sensitive adhesive sheet of the present invention)
Next, a method for producing the pressure-sensitive adhesive sheet of the present invention will be described.
The production method of the present invention provides the layer (Xβ) and the layer (Y1) on a base material or a release material from the viewpoint of productivity and from the viewpoint of easily forming a concave portion and a flat surface on the surface (α) of the resin layer. ), And a resin layer obtained by laminating the layer (Xα) in this order, at least the surface (α) of the layer (Xα) has adhesiveness, and one side selected arbitrarily on the surface (α) A method for producing a pressure-sensitive adhesive sheet having one or more recesses in a region (Q) surrounded by a 1 mm square, wherein the layer (Xβ) contains a resin and substantially contains a tackifier The layer (Y1) is formed using a composition (xβ) that does not include the resin and the fine particles, contains substantially no tackifier, and has a content of the fine particles of 15% by mass or more ( y1), and the layer (Xα) contains 100 parts by mass of an adhesive resin and 1 part by mass or more of a tackifier. Formed using Narubutsu (X [alpha).

In the production method of the present invention, the composition (xβ) does not substantially contain a tackifier, the composition (y1) contains 15% by mass or more of fine particles, and does not substantially contain a tackifier. When only the composition (xα) contains 100 parts by mass of an adhesive resin and 1 part by mass or more of a tackifier, even if a coating film is formed by high-speed application of 8 m / min or more, air bleeding and blister resistance are achieved. Since the concave portion and the flat surface can be formed on the surface (α) that can improve the adhesiveness and the adhesive property, the productivity of the adhesive sheet can be remarkably improved.
Furthermore, when the base material is provided on the surface (β) side, the adhesion between the base material and the surface (β) of the resin layer can be improved, and when the release material is provided on the surface (β) side. In this case, the releasability of the release material from the surface (β) can be improved.

(Layer (Xβ), Composition (xβ))
The layer (Xβ) is formed using a composition (xβ) containing a resin and substantially not containing a tackifier.
The content of the resin in the composition (xβ) is usually 30% by mass or more, preferably 40% by mass or more, based on the total amount of the composition (xβ) (100% by mass (excluding the diluting solvent)). It is more preferably at least 50% by mass, more preferably at least 55% by mass, further preferably at least 60% by mass, still more preferably at least 70% by mass, and preferably at most 100% by mass, more preferably 99.9% by mass. % By mass, more preferably 95% by mass or less.

  Examples of the resin contained in the composition (xβ) include a resin constituting the above-mentioned resin portion (X), and it is preferably an adhesive resin, more preferably an adhesive resin having a functional group, and The acrylic resin (A) having a functional group is more preferred, and the above-mentioned acrylic copolymer (A1) is even more preferred.

The composition (xβ) preferably further contains a crosslinking agent (B).
Examples of the crosslinking agent contained in the composition (xβ) include the crosslinking agent contained in the resin portion (X) described above, and the composition (xβ) contains a metal chelate-based crosslinking agent and an epoxy-based crosslinking agent. , And one or more selected from aziridine-based crosslinking agents, more preferably a metal-chelating crosslinking agent, and even more preferably an aluminum-chelating crosslinking agent.
Further, as one embodiment of the present invention, it is preferable that the composition (xβ) contains both a metal chelate-based crosslinking agent and an epoxy-based crosslinking agent. When the composition (xβ) contains both a metal chelate crosslinking agent and an epoxy crosslinking agent, a suitable content ratio of the metal chelate crosslinking agent to the epoxy crosslinking agent in the composition (xβ) [metal chelate crosslinking agent / Epoxy-based crosslinking agent] is as described above.
The content of the crosslinking agent is preferably 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and still more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the resin contained in the composition (xβ). It is 3 to 7.0 parts by mass.

Further, the composition (xβ) may contain the fine particles described above.
However, the content of the fine particles in the composition (xβ) is less than 15% by mass, and is smaller than the content of the resin contained in the composition (xβ).
The content of the fine particles in the specific composition (xβ) is preferably less than 15% by mass with respect to the total amount of the composition (xβ) (100% by mass (excluding the diluting solvent)). Is 0 to 13% by mass, more preferably 0 to 10% by mass, still more preferably 0 to 5% by mass, and still more preferably 0% by mass.

(Layer (Y1), Composition (y1))
From the viewpoint of further improving the adhesive properties of the surface (α), the layer (Y1) contains a resin and fine particles, does not substantially contain a tackifier, and has a content of the fine particles of 15% by mass or more. It is formed using the object (y1).
The composition (y1) is a material for forming the particle portion (Y), and the resin contained in the composition (y1) includes the same resin as that contained in the composition (xβ) described above.
The resin contained in the composition (y1) is preferably an adhesive resin, and similarly to the composition (xβ), a resin having a functional group is preferable, and the acrylic resin (A) having a functional group described above is more preferable. Preferably, the above-mentioned acrylic copolymer (A1) is more preferable.
The content of the resin in the composition (y1) is generally 0 to 85% by mass, preferably 1 to 80% by mass based on the total amount of the composition (y) (100% by mass (excluding the diluting solvent)). %, More preferably 5 to 75% by mass, still more preferably 10 to 70% by mass, and still more preferably 20 to 65% by mass.

The fine particles contained in the composition (y1) include those described above. From the viewpoint of forming a void portion (Z) in the resin layer and forming a pressure-sensitive adhesive sheet having improved blister resistance, silica particles are used. , Metal oxide particles, and smectite are preferred.
The content of the fine particles in the composition (y1) is determined from the viewpoint of easily forming irregular concave portions and flat surfaces formed by self-forming the resin layer on the surface (α) of the resin layer. It is at least 15% by mass, preferably 20 to 100% by mass, more preferably 25 to 90% by mass, and still more preferably the total amount of (y1) (100% by mass (excluding the diluting solvent)). The content is 30 to 85% by mass, more preferably 35 to 80% by mass.

From the viewpoint of the dispersibility of the fine particles, the composition (y1) more preferably contains a resin together with the fine particles and further contains a crosslinking agent. Further, general-purpose additives may be further included. The components (resin, cross-linking agent, and general-purpose additive) other than the fine particles contained in the composition (y1) serve as a material for forming the resin portion (X).
Examples of the cross-linking agent contained in the composition (y1) include the same cross-linking agents contained in the above-mentioned resin portion (X), and the preferred embodiments thereof are also the same.
Further, as one embodiment of the present invention, it is preferable that the composition (y1) contains both a metal chelate crosslinking agent and an epoxy crosslinking agent. When the composition (y1) contains both a metal chelate-based crosslinker and an epoxy-based crosslinker, a suitable content ratio of the metal chelate-based crosslinker and the epoxy-based crosslinker in the composition (y1) [metal chelate-based crosslinker / Epoxy-based crosslinking agent] is as described above.
The content of the crosslinking agent in the composition (y1) is preferably 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the resin contained in the composition (y1). Parts, more preferably 0.3 to 7.0 parts by mass.

(Layer (Xα), Composition (xα))
The layer (Xα) is formed from a composition (xα) containing 100 parts by mass of an adhesive resin and 1 part by mass or more of a tackifier from the viewpoint of further improving the adhesive properties of the surface (α).
The composition (xα) is a material for forming the resin portion (X) and contains a tackifier together with the tacky resin, and may further contain the above-mentioned crosslinking agent and general-purpose additive.
The details of the adhesive resin are as described above. From the viewpoint of further improving the adhesive properties and easily forming a concave portion and a flat surface on the surface (α) of the resin layer, the acrylic resin having a functional group as described above It is preferable to include
The functional group is a group serving as a starting point of crosslinking with a crosslinking agent, and examples thereof include a hydroxy group, a carboxy group, an epoxy group, an amino group, a cyano group, a keto group, and an alkoxysilyl group. preferable.
From the above viewpoint, the content of the acrylic resin is preferably 25 to 100% by mass, more preferably 50 to 100% by mass, based on the total amount (100% by mass) of the resin contained in the resin portion (X). , More preferably 70 to 100% by mass, further preferably 80 to 100% by mass, and still more preferably 100% by mass.

The tackifier used in the present invention is a component that supplementarily improves the adhesive strength of the adhesive resin, and refers to an oligomer having a weight average molecular weight (Mw) of usually less than 10,000. The details of the tackifier are as described above, and they can be used alone or in combination of two or more.
The content of the tackifier contained in the composition (xα) is 1 part by mass with respect to 100 parts by mass of the adhesive resin in the composition (xα) from the viewpoint of further improving the adhesive properties of the surface (α). Or more, preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 10 parts by mass or more, and the upper limit thereof is preferably 400 parts by mass or less, more preferably 150 parts by mass or less, More preferably, it is 80 parts by mass or less, even more preferably 50 parts by mass or less.
Further, the content of the tackifier with respect to 100% by mass of the total mass of the resin layer is preferably 2 to 60% by mass, more preferably 4 to 60% by mass, and still more preferably 6 to 20% by mass.

The composition (xα) preferably further contains a crosslinking agent.
Examples of the cross-linking agent contained in the composition (xα) include the cross-linking agent contained in the resin portion (X) described above. , And one or more selected from aziridine-based crosslinking agents, more preferably a metal-chelating crosslinking agent, and even more preferably an aluminum-chelating crosslinking agent.
Further, as one embodiment of the present invention, it is preferable that the composition (xα) contains both a metal chelate-based crosslinking agent and an epoxy-based crosslinking agent. When the composition (xα) contains both a metal chelate-based crosslinking agent and an epoxy-based crosslinking agent, a suitable content ratio of the metal chelate-based crosslinking agent and the epoxy-based crosslinking agent in the composition (xα) [metal-chelated-based crosslinking agent / Epoxy-based crosslinking agent] is as described above.
The content of the crosslinking agent is preferably 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and still more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the resin contained in the composition (xα). It is 3 to 7.0 parts by mass.

<Aspects of the production method of the present invention>
Although there is no particular limitation on the production method of the present invention, it is easy to form a concave portion and a flat surface on the surface (α) of the resin layer from the viewpoints of adhesiveness and productivity, and improve air bleeding property and blister resistance. From the viewpoint of the following, the manufacturing method according to the first embodiment and the manufacturing method according to the second embodiment described below are preferable.

<The manufacturing method of the first embodiment>
The production method of the first aspect has at least the following steps (1A) and (2A).
Step (1A): a coating (xβ ′) composed of the composition (xβ), a coating (y1 ′) composed of the composition (y1), and a coating composed of the composition (xα) on a substrate or a release material Step (2A): simultaneously forming the coating film (xβ ′), the coating film (y1 ′), and the coating film (xα ′) formed in the step (1A). Drying to form layer (Xβ), layer (Y1), and layer (Xα)

<Step (1A)>
Step (1A) comprises a coating film (xβ ′) composed of the composition (xβ), a coating film (y1 ′) composed of the composition (y1), and a composition (xα) on a substrate or a release material. This is a step of forming a coating film (xα ′) by laminating in this order.
When forming the coating film, a solvent is blended with the composition (xβ), the composition (y1), and the composition (xα) to facilitate the formation of the coating film, and the form of the composition solution is adjusted. After that, it is preferable to apply.
Examples of such a solvent include water and an organic solvent.
Examples of the organic solvent include toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropyl alcohol, t-butanol, s-butanol, acetylacetone, cyclohexanone, n-hexane, cyclohexane and the like. . These solvents may be used alone or in combination of two or more.

As a method of forming the coating films (xβ ′), (y1 ′) and (xα ′), after forming (xβ ′), a coating film (y1 ′) is formed on the coating film (xβ ′), A method of sequentially forming the coating film (xα ′) on the coating film (y1 ′) may be used. From the viewpoint of productivity, the coating film (xβ ′), the coating film (y1 ′), and the coating film (xα ′) May be simultaneously applied by a multi-layer coater to form.
Examples of the coater used when sequentially forming each coating film include a spin coater, a spray coater, a bar coater, a knife coater, a roll coater, a knife roll coater, a blade coater, a gravure coater, a curtain coater, a die coater, and the like. .
Examples of the coater used for simultaneous coating with a multilayer coater include a curtain coater and a die coater. Among them, a die coater is preferable from the viewpoint of operability.

  Coating speed when forming a coating film (xβ ′), a coating film (y ′), and a coating film (xα ′) using the composition (xβ), the composition (y1), and the composition (xα) Is preferably 8 m / min or more, more preferably 10 m / min or more, further preferably 12 m / min or more, and still more preferably 15 m / min or more, from the viewpoint of productivity.

The coating amount of the coating film (xα ′) is preferably from 1.5 to 800 g / m ² , more preferably from 5 to 500 g / m ² , and still more preferably from 10 to 300 g, from the viewpoint of improving the air release property and the adhesive property. / M ² , more preferably 20 to 200 g / m ² .
The coating amount of the coating film (y1 ′) is preferably from 1.5 to 800 g / m ² , more preferably from 5 to 500 g / m ² , and still more preferably from 10 to 300 g, from the viewpoint of improving the air bleeding property and the adhesive property. / M ² , more preferably 20 to 200 g / m ² .
The ratio [(xα ') / (y1')] of the coating amount of the coating film (xα ') and the coating film (y1') is preferably 100/5 to 5 from the viewpoint of improving the air bleeding property and the adhesive property. The ratio is 100/2000, more preferably 100/50 to 100/1500, and still more preferably 100/100 to 100/1000.

In the step (1A), after forming at least one of the coating film (xβ ′), the coating film (y1 ′), and the coating film (xα ′), the coating film is cured before moving to the step (2A). Pre-drying treatment may be performed to such an extent that the reaction does not proceed.
For example, after forming each of the coating film (xβ ′), the coating film (y1 ′), and the coating film (xα ′), the above-described predrying treatment may be performed each time, and the coating film (xβ ′) ) And the coating film (y1 ′), the coating film (xα ′) may be formed after performing the above-mentioned pre-drying treatment.
The drying temperature at the time of performing the pre-drying treatment in the step (1A) is usually appropriately set to a temperature range in which curing of the formed coating film does not proceed, but is preferably set in the step (2A). It is below the drying temperature. The specific drying temperature indicated by the definition of “less than the drying temperature in step (2A)” is preferably 10 to 45 ° C., more preferably 10 to 34 ° C., and still more preferably 15 to 30 ° C.

<Step (2A)>
In the step (2A), the coating film (xβ ′), the coating film (y1 ′), and the coating film (xα ′) formed in the step (1A) are simultaneously dried to form a layer (Xβ), a layer (Y1), and This is a step of forming a layer (Xα).
In the step (2A), the formed coating film (xβ ′), coating film (y1 ′), and coating film (xα ′) are simultaneously dried to include the resin portion (X) and the particle portion (Y). A resin layer is formed.
Further, by the step (2A), an irregular concave portion is effectively formed on the surface (α) of the layer (Xα), so that the shape of the flat surface also becomes irregular. As a result, it is possible to obtain an adhesive sheet having excellent adhesive strength, air bleeding property, and blister resistance.
The void portion (Z) can be easily formed by using at least one selected from silica particles, metal oxide particles, and smectite as the fine particles contained in the composition (y1).
The lower the drying temperature, the greater the difference in height of the recesses formed, but the number of recesses formed tends to decrease.

<Production method according to second embodiment>
The production method of the second aspect has at least the following steps (1B) and (2B).
Step (1B): On the surface of the substrate or the release material, on the layer (Xβ) formed from the composition (xβ), on the coating (y1 ′) composed of the composition (y1), and on the composition (xα) Step (2B): The coating film (y1 ′) and the coating film (xα ′) formed in the step (1B) are simultaneously dried to form a layer. Forming (Y1) and layer (Xα)

<Step (1B)>
In the step (1B), a coating film (y1 ′) composed of the composition (y1), a coating film (y1 ′) formed on the layer (Xβ) formed of the composition (xβ), and a composition ( This is a step of laminating and forming a coating film (xα ′) composed of xα) in this order.
In the step (1B), the “layer (Xβ) mainly containing the resin portion (X)” includes a coating film (xβ ′) composed of the composition (xβ) containing a resin and substantially not containing a tackifier. It can be formed by drying.
Since the layer (Xβ) is formed from the composition (xβ), the layer (Xβ) may contain a crosslinking agent, a general-purpose additive, and the like, in addition to the resin. The content of the resin portion (X) in the layer (Xβ) is as described above.

As a method for forming the layer (Xβ), a coating film (xβ ′) composed of a composition (xβ) containing a resin is formed on a base material or a release material, and the coating film (xβ ′) is dried and formed. can do.
The drying temperature at this time is not particularly limited, and is preferably 35 to 200 ° C, more preferably 60 to 180 ° C, further preferably 70 to 160 ° C, and still more preferably 80 to 140 ° C.

In the production method of the second embodiment, the coating film (y1 ′) and the coating film (xα ′) are formed in this order on the layer (Xβ) obtained after drying, not on the coating film (xβ ′). This is different from the manufacturing method of the above-described first embodiment in that it is formed by:
Also in the step (1B), it is preferable that the composition (y1) and the composition (xα) are mixed with the above-described solvent to form a solution of the composition, and then applied.
As a method for forming the coating film (y1 ′) and the coating film (xα ′), after forming the coating film (y1 ′) on the layer (Xβ), the coating film (xα ′) is formed on the coating film (y1 ′). ) May be formed sequentially using the above-described coater, or a method of simultaneously applying and forming the coating film (y1 ′) and the coating film (xα ′) using the above-described multilayer coater. Good.

The coating speed when forming the coating film (y ′) and the coating film (xα ′) using the composition (y1) and the composition (xα) is preferably at least 8 m / min from the viewpoint of productivity. , More preferably at least 10 m / min, even more preferably at least 12 m / min, even more preferably at least 15 m / min.
Coating amount of coating film (xα ′), coating amount of coating film (y1 ′), and ratio of coating amount of coating film (xα ′) and coating film (y1 ′) [(xα ′) / (y1 ′) ] Is the same as the above-mentioned step (1A).
In this step (1B), after forming the coating film (y1 ′) or after forming the coating film (y1 ′) and the coating film (xα ′), before moving to the step (2B), A pre-drying treatment to the extent that the curing reaction does not proceed may be performed.
The conditions of the pre-drying treatment in this step (1B) are the same as those in the above-mentioned step (1A).

<Step (2B)>
The step (2B) is a step of simultaneously drying the coating film (y1 ′) and the coating film (xα ′) formed in the step (1B) to form a layer (Y1) and a layer (Xα).
The preferable range of the drying temperature in the step (2B) is the same as that in the step (1B).
By this step (2B), a resin layer including the resin portion (X) and the particle portion (Y) is formed.
In addition, by the step (2B), the irregular concave portions are effectively formed on the surface (α) of the layer (Xα), and the irregular concave portions are formed, so that the shape of the flat surface is also irregular. Become.

(Adhesive sheet)
The following pressure-sensitive adhesive sheet is obtained by the production method of the present invention.
A resin layer obtained by laminating a layer (Xβ), a layer (Y1), and a layer (Xα) in this order on a base material or a release material, and at least the surface (α) of the layer (Xα) is tacky An adhesive sheet having
Layer (X?) Comprises a resin, a layer formed from a substantially free composition (X?) A tackifier,
The layer (Y1) is a layer formed from the composition (y1) containing a resin and fine particles, substantially not containing a tackifier, and having a content of the fine particles of 15% by mass or more,
A pressure-sensitive adhesive sheet, wherein the layer (Xα) is a layer formed from a composition (xα) containing 100 parts by weight of a pressure-sensitive resin and 1 part by weight or more of a tackifier.
The configuration of the pressure-sensitive adhesive sheet of the present invention is as described above.
The pressure-sensitive adhesive sheet of the present invention has an irregular recess on the surface (α) of the layer (Xα).
The recess is formed by self-forming the resin layer.
In the pressure-sensitive adhesive sheet of the present invention, the layer (Y1) may contain a tackifier transferred from the layer (Xα).

  The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples. The physical properties in the following Production Examples and Examples are values measured by the following methods.

<Mass average molecular weight (Mw) of resin>
Using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8020"), the value was measured under the following conditions, and the value measured in terms of standard polystyrene was used.
(Measurement condition)
-Column: "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL", "TSK gel G1000HXL" (all manufactured by Tosoh Corporation)-Column temperature: 40 ° C
・ Developing solvent: tetrahydrofuran ・ Flow rate: 1.0 mL / min

<Measurement of volume average secondary particle diameter of silica particles>
The volume average secondary particle diameter of the silica particles was determined by measuring the particle size distribution by a Coulter counter method using a Multisizer 3 machine (manufactured by Beckman Coulter, Inc.).

<Measurement of resin layer thickness>
The thickness was measured using a constant-pressure thickness measuring instrument (model number: “PG-02J”, standard: JIS K6783, Z1702, Z1709) manufactured by TECLOCK Co., Ltd.
Specifically, after measuring the total thickness of the pressure-sensitive adhesive sheet to be measured, the value obtained by subtracting the previously measured thickness of the base material or the release sheet was defined as “the thickness of the resin layer”.

Production Examples x-1 to x-3
(Preparation of Resin Composition Solutions (xβ-1) and (xα-1) to (xα-2))
To a solution of the acrylic resin having the type and solid content shown in Table 1, a crosslinking agent and a tackifier having the type and blending amount shown in Table 1 were added, and the diluting solvent shown in Table 1 was used. After dilution, solutions (xβ-1) and (xα-1) to (xα-2) of the resin composition having the solid content concentrations shown in Table 1 were prepared.

The details of each component described in Table 1 used for preparing the resin composition solutions (xβ-1) and (xα-1) to (xα-2) are as follows.
<Acrylic resin solution>
Solution (i): contains acrylic resin (xi) (acrylic copolymer having a structural unit derived from a raw material monomer composed of BA / AA = 90/10 (mass%), Mw: 470,000) A mixed solution of toluene and ethyl acetate having a solid content concentration of 37.0% by mass.
Solution (ii): Acrylic resin (x-ii) (2EHA / VAc / AA = 75/23/2 (% by mass)) Acrylic copolymer having a structural unit derived from a raw material monomer, Mw: 66 And a mixed solution of toluene and ethyl acetate having a solid content of 33.0% by mass.
Solution (iii): Acrylic resin (x-iii) (2EHA / BA / VAc / AA = 70/20/5/5 (% by mass)) Acrylic copolymer having a structural unit derived from a raw material monomer , Mw: 630,000) containing 33.5% by mass of solid content and containing toluene and ethyl acetate.
In addition, the abbreviations of the raw material monomers constituting the above-mentioned acrylic copolymer are as follows.
-BA: n-butyl acrylate-2EHA: 2-ethylhexyl acrylate-AA: acrylic acid-VAc: vinyl acetate

<Crosslinking agent>
-Al-based cross-linking agent: Product name "M-5A", manufactured by Soken Chemical Co., Ltd., aluminum chelate-based cross-linking agent, solid content concentration = 4.95% by mass.
-Epoxy crosslinking agent: A solution of an epoxy crosslinking agent obtained by diluting "TETRAD-C" (product name, manufactured by Mitsubishi Gas Chemical Co., Ltd.) with toluene to a solid content concentration of 5% by mass.

<Tackifier>
-Rosin ester type TF: Rosin ester type polymer, Mw: less than 10,000, softening point: 135 ° C.
Terpene TF: aromatic modified terpene polymer, Mw: less than 10,000, softening point: 115 ° C.
-Hydrogenated terpene TF: hydride of an aromatic modified terpene polymer, Mw: less than 10,000, softening point: 100 ° C.

<Diluent solvent>
-Mixed solvent (1): A mixed solvent obtained by mixing toluene / isopropyl alcohol (IPA) = 35/65 (mass ratio).
A mixed solvent (2): a mixed solvent obtained by mixing toluene / isopropyl alcohol (IPA) = 40/60 (mass ratio).

Production Example f-1
(Preparation of Fine Particle Dispersion (f-1))
Solution (i) containing the above-mentioned acrylic resin (xi) (BA / AA = 90/10 (% by mass)) Acrylic copolymer (Mw: 470,000) having a structural unit derived from a raw material monomer (A mixed solution of toluene and ethyl acetate having a solid content of 37.0% by mass).
With respect to 100 parts by mass of the solution (i) (solid content: 37.0 parts by mass), silica particles (product name “Nip Seal E-200A”, manufactured by Tosoh Silica Co., Ltd., volume average secondary particle diameter) were used as fine particles. : 3 μm) and 55.5 parts by mass (solid content: 55.5 parts by mass) and toluene were added to disperse the fine particles, and the solid concentration including the acrylic resin (xi) and the silica particles was 30 parts by mass. % Fine particle dispersion (f-1) was prepared.

Production Examples y-1 to y-2
(Preparation of coating liquids (y-1) to (y-2) for forming coating film (y '))
A coating film (y ') having a solid content concentration shown in Table 2 was formed by adding a fine particle dispersion, an acrylic resin solution, a cross-linking agent, a tackifier, and a diluting solvent of the kind and blending amount shown in Table 2. Application liquids (y-1) to (y-2) were prepared.

The details of each component shown in Table 2 used for preparing the coating liquids (y-1) to (y-2) for forming the coating film (y ') are as follows.
<Particle dispersion>
-Dispersion (f-1): A fine particle dispersion (f-1) containing an acrylic resin (xi) and silica particles and having a solid content concentration of 30% by mass, prepared in Production Example f-1.
<Acrylic resin solution>
Solution (i): contains acrylic resin (xi) (acrylic copolymer having a structural unit derived from a raw material monomer composed of BA / AA = 90/10 (mass%), Mw: 470,000) A mixed solution of toluene and ethyl acetate having a solid content concentration of 37.0% by mass.
<Crosslinking agent>
-Al-based cross-linking agent: Product name "M-5A", manufactured by Soken Chemical Co., Ltd., aluminum chelate-based cross-linking agent, solid content concentration = 4.95% by mass.
<Tackifier>
-Rosin ester type TF: Rosin ester type polymer, Mw: less than 10,000, softening point: 135 ° C.
Terpene TF: aromatic modified terpene polymer, Mw: less than 10,000, softening point: 115 ° C.
-Hydrogenated terpene TF: hydride of an aromatic modified terpene polymer, Mw: less than 10,000, softening point: 100 ° C.
<Diluent solvent>
-Mixed solvent (3): IPA / CHN: Mixed solvent composed of isopropyl alcohol (IPA) and cyclohexanone (CHN) (IPA / CHN = 95/5 (mass ratio)).

Examples 1 and 2, Comparative Example 1
(1) Formation of Coating Film A polyethylene terephthalate (PET) film provided with an aluminum evaporation layer on one side (manufactured by Lintec Corporation, product name “FNS Keshi N50”, thickness 50 μm) was used as a base material.
On the aluminum vapor-deposited layer of the PET film, a solution (xβ-1) of the resin composition prepared in Production Example x-1 and a coating film prepared in Production Examples y-1 to y-2 shown in Table 3 ( y ′) Any of the forming coating liquids (y-1) to (y-2) and the solution (xα-1) of the resin composition prepared in Production Examples x-2 to x-3 shown in Table 3. Any of (xα-2) was simultaneously applied in this order at a coating speed of 40 m / min using a multilayer die coater (width: 250 mm), and a coating film (xβ ′), a coating film (y ′) and A coating (xα ′) was simultaneously formed.
The flow rate of each solution (coating solution) for forming the coating film (xβ ′), the coating film (y ′) and the coating film (xα ′), and the coating amount of each coating film are shown in Table 3. It is as follows.

(2) Drying process The three layers of the coating film (xβ ′), the coating film (y ′) and the coating film (xα ′) were simultaneously dried at a drying temperature of 100 ° C. for 2 minutes to obtain a resin portion (X ) And a particle portion (Y), a resin layer having a thickness shown in Table 3 was formed.
Then, on the surface (α) of the formed resin layer, it is laminated so as to be bonded to a release-treated surface of a release film (product name “SP-PET381031”, manufactured by Lintec Corporation) as a release material. A sheet was prepared.

  Using the pressure-sensitive adhesive sheets with a base material produced in Examples and Comparative Examples, measurement or observation was performed on the resin layer of the pressure-sensitive adhesive sheet and the properties of the pressure-sensitive adhesive sheet by the following methods. Table 4 shows the results.

<State of surface (α) of resin layer>
(1) Presence of irregular shaped recess
On the surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in the example and the comparative example, four areas (D) surrounded by a rectangle of 8 mm × 10 mm are arbitrarily selected, and the inside of each area (D) is selected. Observation and photographing were performed with a digital microscope (manufactured by KEYENCE CORPORATION, product name "Digital Microscope VHX-1000", magnification: 50 times) from the surface (α) side in a plan view (stereoscopic view as necessary).
In the photographing, more specifically, the focus was moved in order from the top of a portion that was visually determined to be a flat surface from the direction A in FIG. . Furthermore, using a digital microscope (magnification: 50 times), a connected image in which arbitrarily selected ranges adjacent to each other on the surface (α) are connected by the image connecting function of the digital microscope is acquired, and in the obtained connected image, , An area surrounded by a rectangle having a length of 8 mm and a width of 10 mm was arbitrarily selected, and this was designated as "image of area (D)".
If it is not possible to determine whether the surface is a flat surface by visual inspection of the image, a squeegee should be applied to the translucent adherend having a smooth surface on the surface (α) of the resin layer so as not to apply a load as much as possible. The image was taken by hand and the interface between the smooth surface of the translucent adherend and the surface (α) 12a of the resin layer 12 was photographed from the direction A in FIG. 5, and it was determined that the attached portion was a flat surface. did. A non-alkali glass (product name "Eagle XG", manufactured by Corning Corporation) was used as the translucent adherend having a smooth surface.
The image of the obtained region (D) was observed to confirm the presence or absence of the irregular concave portions, and the presence or absence of the irregular concave portions on the surface (α) was evaluated according to the following criteria.
A: In any of the selected regions (D), irregular concave portions were confirmed.
B: An irregular-shaped recess was confirmed in a part of the selected region (D).
C: In any of the selected regions (D), the presence of the concave portion could not be confirmed.

(2) Area ratio of flat surface
Based on the “image of region (D)” obtained in (1) above, automatic area measurement was performed using the same digital microscope as described above, and the area of each flat surface existing in region (D) was obtained. .
In the automatic area measurement, after the flat surface existing in the region (D) is binarized by a digital microscope and, if necessary, visual image processing, the numerical value (area) of the obtained binarized image is obtained. The measurement was performed, and the area of each flat surface was measured. When there were a plurality of flat surfaces, the area of each flat surface was measured. The “area ratio (%) occupied by the flat surface”, which is the ratio of the total area of the obtained flat surfaces to the total area (D), was calculated.
The conditions for automatic area measurement are as follows.
(Automatic area measurement conditions)
・ Extraction mode: Luminance (weak noise reduction)
-Extraction area: Extract a rectangle of 8 mm in length x 10 mm in width by specifying a numerical value (rectangle)-Shaping the extraction area: Removing grains (removing area of 100 µm ² or less)

<Air bleeding property>
A pressure-sensitive adhesive sheet with a base material having a size of 50 mm in length and 50 mm in width was stuck to a melamine coated plate as an adherend so as to generate air pockets. Then, the presence or absence of air pockets after pressure bonding using a squeegee was observed, and the air bleeding property of each pressure-sensitive adhesive sheet was evaluated according to the following criteria.
A: The air pocket has completely disappeared, and the air bleeding property is excellent.
F: Part of the air pocket remains, and the air bleeding property is inferior to the pressure-sensitive adhesive sheet of the above A evaluation.

<Blister resistance>
An adhesive sheet having a size of 50 mm long × 50 mm wide is attached to a polymethyl methacrylate plate (manufactured by Mitsubishi Rayon Co., Ltd., product name “Acrylite L001”) having a size of 70 mm × 150 mm × 2 mm, and using a squeegee. The sample was pressed to produce a test sample.
After the test sample was allowed to stand at 23 ° C. for 12 hours, it was allowed to stand in a hot air dryer at 80 ° C. for 1.5 hours, and further left in a hot air dryer at 90 ° C. for 1.5 hours to promote heating. Was visually observed, and the blister resistance of each pressure-sensitive adhesive sheet was evaluated according to the following criteria.
A: No blister was confirmed.
B: Blisters were partially observed.
C: Blisters were confirmed on the entire surface.

<Adhesive strength>
After cutting the pressure-sensitive adhesive sheet with a base material prepared in each of Examples and Comparative Examples into a size of 25 mm in length and 300 mm in width, the surface (α) of the resin layer of the pressure-sensitive adhesive sheet was measured at 23 ° C. and 50% RH (relative humidity). Under the same environment, the laminated body attached to the stainless steel plate (SUS304, No. 360 polishing) was allowed to stand for 24 hours in the same environment.
After standing, the adhesive strength of each adhesive sheet was measured by a 180 ° peeling method at a pulling speed of 300 mm / min based on JIS Z0237: 2000.

The pressure-sensitive adhesive sheets obtained in Examples 1 and 2 show excellent air bleeding property and blister resistance, have a good balance with the pressure-sensitive properties, and have a higher productivity than the pressure-sensitive adhesive sheets obtained in Comparative Example 1. Good results.
6, 7 and 8 show the randomly selected length 8 mm × width 10 mm of the exposed surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Examples 1 and 2 and Comparative Example 1, respectively. It is a binarized image of an image obtained by photographing a region (D) surrounded by a rectangle from the surface (α) side using a digital microscope. That is, the height of the rectangular images in FIGS. 6 and 7 corresponds to “8 mm” and the width corresponds to “10 mm”.
In these binarized images, the black portion is a flat surface and the white portion corresponds to a concave portion. In FIG. 6 of Example 1 and FIG. 7 of Example 2, compared to FIG. 8 of Comparative Example 1, Since it has a denser flat surface and concave portions, it is considered that it exhibits excellent air bleeding property and blister resistance, and has a good balance with the adhesive property.

  The pressure-sensitive adhesive sheet of one embodiment of the present invention is useful as a pressure-sensitive adhesive sheet having a large area to be applied, which is used for identification or decoration, masking for painting, surface protection of a metal plate or the like.

1a, 11a, 12a, 1b, 2a, 2b Adhesive sheet 11 Base material 12 Resin layer 12a Surface (α)
12b Surface (β)
(X) Resin part (X)
(Y) Particle part (Y)
(Xβ) Layer mainly containing resin portion (X) (Xβ)
(Xα) Layer (Xα) mainly containing resin portion (X)
(Y1) Layer (Y1) containing 15% by mass or more of particle portion (Y)
13, 13a, 131, 132 Concave part 14 Flat surface 14a Flat part 15a Convex part 21, 22 Release material 50 Square 51, 52 Diagonal line 60 Cross section (P1)
61, 62 cross section

Claims (18)

A resin layer obtained by laminating a layer (Xβ), a layer (Y1), and a layer (Xα) in this order on a base material or a release material, and at least the surface (α) of the layer (Xα) is tacky A method for producing a pressure-sensitive adhesive sheet having one or more concave portions in a region (Q) surrounded by an arbitrarily selected square having a side of 1 mm on a surface (α),
The layer (Xβ) is formed using a composition (xβ) containing a resin and substantially not containing a tackifier,
The layer (Y1) is formed using a composition (y1) containing a resin and fine particles, substantially not containing a tackifier, and having a content of the fine particles of 15% by mass or more,
The layer (Xα) is formed using the composition (xα) containing 100 parts by mass of the adhesive resin and 1 part by mass or more of the tackifier , and at least the layer (Xα) and the layer (Y1) are dried at the same time. Form,
A method for producing an adhesive sheet. The method for producing a pressure-sensitive adhesive sheet according to claim 1, comprising at least the following steps (1A) and (2A).
Step (1A): a coating (xβ ′) composed of the composition (xβ), a coating (y1 ′) composed of the composition (y1), and a coating composed of the composition (xα) on a substrate or a release material Step (2A): simultaneously forming the coating film (xβ ′), the coating film (y1 ′), and the coating film (xα ′) formed in the step (1A). Drying to form layer (Xβ), layer (Y1), and layer (Xα)   In the step (1A), using the composition (xβ), the composition (y1), and the composition (xα) at an application speed of 8 m / min or more, the coating film (xβ ′) and the coating film (y ′) And the coating film (xα ′). The method for producing a pressure-sensitive adhesive sheet according to claim 1, comprising at least the following steps (1B) and (2B).
Step (1B): On the surface of the substrate or the release material, on the layer (Xβ) formed from the composition (xβ), on the coating (y1 ′) composed of the composition (y1), and on the composition (xα) Step (2B): The coating film (y1 ′) and the coating film (xα ′) formed in the step (1B) are simultaneously dried to form a layer. Forming (Y1) and layer (Xα)   In the step (1B), a coating film (y1 ′) and a coating film (xα ′) are formed using the composition (y1) and the composition (xα) at an application speed of 8 m / min or more, respectively. 5. The method for producing a pressure-sensitive adhesive sheet according to 4.   The method for producing a pressure-sensitive adhesive sheet according to any one of claims 2 to 5, wherein an irregular recess is formed on the surface (α) of the layer (Xα) by the step (2A) or (2B).   7. The composition according to claim 1, wherein the content of the tackifier contained in the composition (xα) is 400 parts by mass or less based on 100 parts by mass of the adhesive resin in the composition (xα). 13. The method for producing a pressure-sensitive adhesive sheet according to item 10. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the coating amount of the coating film (xα ′) is 1.5 to 800 g / m ² . The coating amount of the coating film (y1 ') is 1.5~800g / ^{m 2,} the production method of the adhesive sheet according to any one of claims 1-8.   The coating amount ratio of the coating film (xα ') and the coating film (y1') [(xα ') / (y1')] is 100/5 to 100/2000. The method for producing a pressure-sensitive adhesive sheet according to claim 1.   The method for producing a pressure-sensitive adhesive sheet according to any one of claims 1 to 10, wherein the content of the tackifier is 2 to 60% by mass relative to the total mass of 100% by mass of the resin layer.   The method for producing an adhesive sheet according to any one of claims 1 to 11, wherein the resin contained in the composition (xβ) and the composition (y1) is an adhesive resin.   The method for producing a pressure-sensitive adhesive sheet according to any one of claims 1 to 12, wherein the pressure-sensitive adhesive resin contained in the composition (xα) is an acrylic resin having a functional group.   The method for producing a pressure-sensitive adhesive sheet according to claim 13, wherein the composition (xα) further comprises at least one selected from a metal chelate-based crosslinking agent, an epoxy-based crosslinking agent, and an aziridine-based crosslinking agent.   The method for producing a pressure-sensitive adhesive sheet according to claim 13, wherein the functional group is a carboxy group.   The method for producing a pressure-sensitive adhesive sheet according to any one of claims 1 to 15, wherein the fine particles contained in the composition (y1) are at least one selected from silica particles, metal oxide particles, and smectite. A resin layer obtained by laminating a layer (Xβ), a layer (Y1), and a layer (Xα) in this order on a base material or a release material, and at least the surface (α) of the layer (Xα) is tacky An adhesive sheet having
Having an irregular recess on the surface (α) of the layer (Xα);
The maximum height difference of one recess is 0.5 μm or more and the thickness of the resin layer or less, the average value of the width of the recess is 1 to 500 μm,
The area ratio occupied by the flat surface existing on the surface (α) is 50 to 90%,
Layer (X?) Comprises a resin, a layer formed from a substantially free composition (X?) A tackifier,
The layer (Y1) is a layer formed from the composition (y1) containing a resin and fine particles, substantially not containing a tackifier, and having a content of the fine particles of 15% by mass or more,
The layer (Xα) is a layer formed from a composition (xα) containing 100 parts by mass of an adhesive resin and 1 part by mass or more of a tackifier.
Adhesive sheet. The pressure-sensitive adhesive sheet according to claim 17 , wherein the recess is formed by self-forming the resin layer.