JPWO2017057405A1 - Adhesive sheet and method for producing adhesive sheet - Google Patents

Abstract

A pressure-sensitive adhesive sheet having a resin layer on a base material or a release material, and at least the surface (α) of the resin layer on the side opposite to the side on which the base material or release material is provided, In (α), there are recesses and a plurality of flat surfaces, and in the region (D) surrounded by a rectangle of 8 mm long × 10 mm wide arbitrarily selected on the surface (α), there are a plurality of flat surfaces, Among the plurality of flat surfaces existing in the region (D), one or more flat surfaces (R) excluding a flat surface having a cumulative relative frequency of 30% or less obtained by adding the relative frequencies from the smaller area of each flat surface The average value of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] of each flat surface (R) is 0.011 to 0.020. I will provide a.

Description

  The present invention relates to a pressure-sensitive adhesive sheet and a method for producing 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 against the adherend and attached.
By the way, for example, a pressure-sensitive adhesive sheet having a large application area used for identification / decoration, coating masking, surface protection of a metal plate, etc., is applied to an adherend with an adhesive layer and an adherend. There is a problem that air pockets are easily generated between the two, and the portion becomes “bulging”, and the pressure-sensitive adhesive sheet is hardly adhered to the adherend.

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 that is artificially arranged in a predetermined pattern is disclosed.
By using such an adhesive sheet, it is said that “air pockets” generated when sticking to an adherend can be released to the outside through a groove artificially formed on the surface of the adhesive layer. ing.

Special table 2001-507732 gazette

However, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which grooves having a specific specific shape as described in Patent Document 1 are arranged in a predetermined pattern is difficult to remove air when the width of the groove is narrow. If it is wide, the surface base material is recessed and not only the appearance is inferior, but also the adhesive strength is reduced.
In addition, since the adhesive sheet has the grooves arranged in a predetermined pattern, the adhesive strength of the place where the grooves are arranged is locally inferior, and when the adhesive sheet is attached to the adherend, the adhesive sheet does not peel off from the place. May occur.
On the other hand, when the pressure-sensitive adhesive sheet is peeled off after being adhered to the adherend, the pressure-sensitive adhesive properties of the pressure-sensitive adhesive sheet are locally different. Therefore, depending on the direction in which the pressure-sensitive adhesive sheet is peeled off, there is a possibility that adhesive residue may be generated 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 shape, adhesive residue may occur on the adherend when peeled in an oblique direction.
Further, when the punching process is performed on the pressure-sensitive adhesive sheet, the groove arrangement pattern and the punching pattern may overlap. In that case, there is a problem that the cutting depth varies, and the cutting cannot be appropriately formed in the adhesive sheet.

Moreover, generally, in order to make it easy to peel off the release material provided on the pressure-sensitive adhesive sheet, there is a case where a process (so-called back cracking process) is performed in which only the release material is cut and a trigger for peeling is provided. When performing the said process, after peeling off a peeling material from an adhesive sheet once and giving a cut | incision in a peeling material, it is common to laminate the peeling material and the adhesive layer of an adhesive sheet again.
However, since the embossed liner is used as the release material in the pressure-sensitive adhesive sheet described in Patent Document 1, it is difficult to follow the emboss pattern of the release material when laminating the release material and the adhesive layer again. It is necessary to prepare another release material that has not been subjected to.

Furthermore, in Patent Document 1, in order to form a fine structure in the pressure-sensitive adhesive layer, a method of laminating the pressure-sensitive adhesive layer and the base material after the pressure-sensitive adhesive is once applied to the emboss liner to form the pressure-sensitive adhesive layer ( The so-called transfer coating method is employed. However, when a base material having a low polarity surface such as a polyolefin base material is used as the base material, sufficient adhesion cannot be obtained at the interface between the base material 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 the adhesive layer.
In addition, as in the pressure-sensitive adhesive sheet described in Patent Document 1, when the pressure-sensitive adhesive sheet having regular grooves extending regularly to the end portion is immersed in the liquid, the liquid infiltrates from the end groove and ends. The part may float and cause peeling. Therefore, the pressure-sensitive adhesive sheet may also be required to have liquid resistance, which is a characteristic that suppresses the entry of liquid from the end portion.

  The present invention has an excellent air bleedability that can easily remove air pockets that can be generated when affixed to an adherend, has good adhesive properties, and can suppress liquid intrusion from the edge. An object of the present invention is to provide a pressure-sensitive adhesive sheet having excellent liquid resistance and a method for producing the pressure-sensitive adhesive sheet.

  In the pressure-sensitive adhesive sheet having a resin layer in which concave portions and a plurality of flat surfaces are present on an adhesive surface, the inventor has a smaller area of each flat surface among a plurality of flat surfaces existing in a predetermined region. A pressure-sensitive adhesive sheet having an average value of the ratio of the area of one or more flat surfaces excluding a flat surface with a cumulative relative frequency of 30% or less and a peripheral length added to the specific range can solve the above problem. The present invention was completed.

That is, the present invention provides the following [1] to [20].
[1] A pressure-sensitive adhesive sheet having a resin layer on a base material or a release material, and at least the surface (α) of the resin layer opposite to the side on which the base material or the release material is provided has adhesiveness. And
The surface (α) has a recess and a plurality of flat surfaces,
In a region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle on the surface (α), there are a plurality of flat surfaces, and among the plurality of flat surfaces present in the region (D), About one or more flat surfaces (R) excluding a flat surface having a cumulative relative frequency of 30% or less obtained by adding a relative frequency from the smaller area of each flat surface,
The adhesive sheet whose average value (L / S) ratio (L / S) of area (S) [micrometer < ² >] of each flat surface (R) and perimeter (L) [micrometer] is 0.011-0.020.
[2] is the average value of the area (S) [[mu] m ^2] and peripheral length (L) ratio of [μm] (L / S) of each flat surface (R) is 0.013 to 0.018, the The pressure-sensitive adhesive sheet according to [1].
[3] Skewness Sk with respect to the normal distribution curve of the ratio (L / S) of the area (S) [μm ² ] to the perimeter (L) [μm] and the frequency of each of the one or more flat surfaces (R) The pressure-sensitive adhesive sheet according to the above [1] or [2], which has a value of −0.1 to 1.6.
[4] The difference between the maximum value and the median of the ratio (L / S) of the area (S) [μm ² ] of one or more flat surfaces (R) to the perimeter (L) [μm] is 0. The pressure-sensitive adhesive sheet according to any one of [1] to [3], which is 0010 to 0.018.
[5] The pressure-sensitive adhesive sheet according to any one of [1] to [4], wherein the shape of the flat surface is indefinite.
[6] The pressure-sensitive adhesive sheet according to any one of [1] to [5], wherein the concave portion has a maximum height difference of 0.5 μm or more.
[7] The above [1] to [6], wherein the surface (α) of the resin layer has at least one flat surface (f1) having a width that allows selection of a region surrounded by a circle having a diameter of at least 100 μm. ] The adhesive sheet as described in any one of.
[8] The surface (α) of the resin layer according to any one of [1] to [7], wherein one or more flat surfaces (f2) having an area of 0.2 mm ² or more are present. Adhesive sheet.
[9] The pressure-sensitive adhesive sheet according to any one of [1] to [8], wherein the concave portion is not formed using a release material having an emboss pattern.
[10] The pressure-sensitive adhesive sheet according to any one of [1] to [9], wherein the resin layer includes a resin part (X) containing a resin and a particle part (Y) made of fine particles.
[11] The pressure-sensitive adhesive sheet according to [10], wherein the mass retention after heating the resin layer at 800 ° C. for 30 minutes is 3 to 90% by mass.
[12] The pressure-sensitive adhesive sheet according to the above [10] or [11], wherein the resin contained in the resin portion (X) includes a pressure-sensitive adhesive resin.
[13] The pressure-sensitive adhesive sheet according to any one of the above [11] or [12], wherein the resin portion (X) further contains one or more selected from a metal chelate crosslinking agent and an epoxy crosslinking agent.
[14] The pressure-sensitive adhesive sheet according to any one of [11] to [13], wherein the fine particles are one or more selected from silica particles, metal oxide particles, and smectites.
[15] The pressure-sensitive adhesive sheet according to any one of the above [1] to [14], wherein the surface (β) of the resin layer on the side on which the base material or release material is provided has adhesiveness.
[16] A layer (X1) mainly containing a resin part (X), a layer (Y1) containing 15% by mass or more of a particle part (Y) from the side on which the base material or release material is provided, And the adhesive sheet as described in any one of said [1]-[15] which is a multilayer structure which laminated | stacked the layer (X (alpha)) mainly containing resin part (X) in this order.
[17] The layer (Xβ) is a layer formed of a composition (xβ) containing a resin and having a fine particle content of less than 15% by mass;
The layer (Y1) is a layer formed from a composition (y) containing 15% by mass or more of fine particles,
The pressure-sensitive adhesive sheet according to the above [16], wherein the layer (Xα) is a layer formed of a composition (xα) containing a resin and having a fine particle content of less than 15% by mass.
[18] A method for producing the pressure-sensitive adhesive sheet according to any one of the above [1] to [15], comprising at least the following steps (1) and (2).
Step (1): a coating film (x ′) comprising a composition (x) containing a resin and having a fine particle content of less than 15% by mass, and a coating film comprising a composition (y) comprising 15% by mass or more of fine particles Step (2) for forming (y ′): Step of simultaneously drying the coating film (x ′) and the coating film (y ′) formed in Step (1) [19] The pressure-sensitive adhesive sheet according to [17] above A method for producing a pressure-sensitive adhesive sheet, comprising at least the following steps (1A) and (2A).
Step (1A): a coating film (xβ ′) composed of a composition (xβ) containing a resin and having a fine particle content of less than 15% by mass on the substrate or the release material, and a composition comprising 15% by mass or more of the fine particles A coating film (y ′) made of the product (y) and a coating film (xα ′) made of a composition (xα) containing a resin and containing fine particles of less than 15% by mass are laminated in this order. Step (2A): The step of simultaneously drying the coating film (xβ ′), the coating film (y ′), and the coating film (xα ′) formed in the step (1A) [20] Adhesion according to the above [17] A method for producing a sheet, which comprises at least the following steps (1B) and (2B).
Step (1B): a coating film comprising a composition (y) containing 15% by mass or more of the fine particles on a layer (Xβ) mainly containing a resin portion (X) provided on a substrate or a release material ( Step (2B) for forming a coating film (xα ′) comprising y ′) and a composition (xα) containing a resin and having a fine particle content of less than 15% by mass in this order: Step (1B) ) The step of simultaneously drying the coating film (y ′) and the coating film (xα ′) formed in

  The pressure-sensitive adhesive sheet of the present invention has excellent air evacuation properties that can easily remove air pockets that may be generated when affixed to an adherend, and also has good pressure-sensitive adhesive properties, so that liquid can enter from the end. It also has excellent liquid resistance that can suppress

It is a cross-sectional schematic diagram of this adhesive sheet which shows an example of a structure of the adhesive sheet of this invention. It is a plane schematic diagram 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. It is a cross-sectional schematic diagram of this resin layer which shows an example of the shape at the surface ((alpha)) side of the resin layer which the adhesive sheet of this invention has. It is a cross-sectional schematic diagram of the measurement sample used for observation of the surface ((alpha)) of the resin layer of the adhesive sheet produced in the Example and the comparative example. (A) Using a digital microscope, a region (D) surrounded by an arbitrarily selected rectangle of 8 mm long × 10 mm wide on the surface (α) of the exposed surface of the resin layer of the pressure-sensitive adhesive sheet produced in Example 1 It is a binarized image of an image obtained by photographing from the surface (α) side. Note that the black portion of the binarized image corresponds to a flat surface and the white portion corresponds to a concave portion. (B) It is the cross-sectional image acquired by observing the cross section of the adhesive sheet produced in Example 1 using the scanning microscope. A region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle (D) of the exposed surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Example 2 was obtained using a digital microscope. It is a binarized image of an image obtained by shooting from the side. Note that the black portion of the binarized image corresponds to a flat surface and the white portion corresponds to a concave portion. A region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle (D) of the exposed surface (α) of the resin layer of the pressure-sensitive adhesive sheet produced in Example 3 was obtained using a digital microscope. It is a binarized image of an image obtained by shooting from the side. Note that the black portion of the binarized image corresponds to a flat surface and the white portion corresponds to a concave portion. A region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle (D) of the exposed surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Example 4 was obtained using a digital microscope. It is a binarized image of an image obtained by shooting from the side. Note that the black portion of the binarized image corresponds to a flat surface and the white portion corresponds to a concave portion. A region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle (D) on the exposed surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Comparative Example 1 was obtained using a digital microscope. It is a binarized image of an image obtained by shooting from the side. Note that the black portion of the binarized image corresponds to a flat surface and the white portion corresponds to a concave portion. A region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle (D) on the exposed surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Comparative Example 2 was obtained using a digital microscope. It is a binarized image of an image obtained by shooting from the side. Note that the black portion of the binarized image corresponds to a flat surface and the white portion corresponds to a concave portion. A region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle (D) of the exposed surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Comparative Example 3 was obtained using a digital microscope. It is a binarized image of an image obtained by shooting from the side. Note that the black portion of the binarized image corresponds to a flat surface and the white portion corresponds to a concave portion. A region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle (D) on the exposed surface (α) of the resin layer of the pressure-sensitive adhesive sheet prepared in Comparative Example 4 was obtained using a digital microscope. It is a binarized image of an image obtained by shooting from the side. Note that the black portion of the binarized image corresponds to a flat surface and the white portion corresponds to a concave portion.

In the present invention, for example, the description of “YY including XX component as main component” or “YY mainly composed of XX component” means that the component with the highest content among the components included in YY is the XX component. It means that there is. As content of the specific XX component in the said description, it is 50 mass% or more normally with respect to the whole quantity (100 mass%) of YY, Preferably it is 65-100 mass%, More preferably, it is 75-100 mass%, Furthermore, 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 value and the upper limit value described in a stepwise manner can be independently combined for a preferable numerical range (for example, a range such as content). 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 make “10 to 60”. You can also.

[Configuration of the pressure-sensitive adhesive sheet of the present invention]
The pressure-sensitive adhesive sheet of the present invention has a resin layer on a base material or a release material, and at least the surface (α) of the resin layer opposite to the side on which the base material or the release material is provided has adhesiveness. In the pressure-sensitive adhesive sheet, the surface (α) has a recess and a plurality of flat surfaces.

FIG. 1 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.
Examples of the pressure-sensitive adhesive sheet according to one aspect of the present invention include a pressure-sensitive adhesive sheet 1a having a resin layer 12 on a substrate 11 as shown in FIG. 1A and a peeling as shown in FIG. An adhesive sheet 1 b having a resin layer 12 on the material 21 is exemplified.

In the pressure-sensitive adhesive sheet of the present invention, at least the surface (α) 12a (hereinafter also simply referred to as “surface (α)”) of the resin layer 12 opposite to the side on which the substrate 11 or the release material 21 is provided is adhesive. And the recess 13 and the flat surface 14 exist.
Therefore, from the viewpoint of handleability, the pressure-sensitive adhesive sheet according to another aspect of the present invention further includes a release material 22 on the surface (α) 12a of the resin layer 12 relative to the pressure-sensitive adhesive sheets 1a and 1b shown in FIG. It is preferable to have a structure such as the pressure-sensitive adhesive sheets 2a and 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, it is preferable that 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 maintaining property 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 part (X) and the particle part (Y) are as described later.

In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, the surface (β) 12b (hereinafter, also simply 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 pressure-sensitive. It may have sex.
Since the surface (β) also has adhesiveness, if the adhesive sheets 1a and 2a shown in FIGS. 1A and 1C are used, the adhesiveness between the resin layer 12 and the substrate 11 is improved, and FIG. If it is the adhesive sheets 1b and 2b shown to b) and (d), it can be set as a double-sided adhesive sheet.

[Requirements for recesses and flat surfaces on the surface (α)]
In the pressure-sensitive adhesive sheet of the present invention, as shown in FIGS. 1A to 1D, the surface (α) 12 a of the resin layer 12 has a recess 13 and a plurality of flat surfaces 14.
The concave portion 13 present on the surface (α) serves as an air discharge passage for escaping an “air pool” generated when the surface (α) of the resin layer of the pressure-sensitive adhesive sheet of the present invention is attached to the adherend. 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 bonded 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 present on the surface (α) of the resin layer is preferably an irregular concave portion 13 as shown in FIG. 2, but a regular concave portion may be present.
However, in one embodiment of the present invention, as shown in FIG. 2, it is preferable that one or more irregular recesses 13 exist on the surface (α) 12 a of the resin layer 12, and the irregular recess 13 is present. It is more preferable that a plurality exist.
Due to the presence of the irregular recesses on the surface (α) of the resin layer, it is possible to obtain a pressure-sensitive adhesive sheet that is further improved in air release and pressure-sensitive adhesive properties.
Further, the presence of a plurality of irregularly shaped recesses causes pressure to be applied from a certain direction, and even when the shape of a part of the recesses present on the surface (α) collapses, the surface (α) has a shape. The maintained recess 13 is likely to exist, and the air escape path can be prevented from disappearing.

  In addition, the length of the recess 13 when the recess 13 existing on the surface (α) is viewed in plan is not particularly limited. That is, the recess 13 includes a relatively long groove shape and a relatively short recess shape.

In one embodiment of the present invention, as shown in FIG. 2, the shape of the flat surface 14 observed from the surface (α) 12 a side of the resin layer 12 is preferably indefinite.
The surface (α) of the resin layer may have a regular flat surface as well as an irregular flat surface 14, but it is preferable that a plurality of irregular concave portions 14 exist.
Unlike the surface of the pressure-sensitive adhesive layer formed by using a release sheet having a general emboss pattern, the adhesive strength is locally increased due to the presence of an irregular flat surface on the surface (α) of the resin layer. It is possible to reduce the number of weak parts and parts having poor air release properties as much as possible. As a result, it is possible to uniformly exhibit excellent air bleeding and adhesive properties with respect to the surface (α) of the resin layer.

In the present invention, the term “indefinite shape” means that there is no regular shape such as a figure that can draw the center such as a circle or an ellipse, and a polygon, and the shape is not regular, and is similar to an individual shape. In particular, the shape of the recess 13 and the flat surface 14 shown in FIG.
On the other hand, examples of “standard” that is not “indefinite” include a circle, an ellipse, and a polygon. In this specification, a “polygon” is a figure in which a diagonal line can be drawn (without protruding outside), and the sum of internal angles is 180 × n (degrees) (n is a natural number) A figure surrounded by straight lines. The polygon includes those whose corners are curved in a round shape.

In the present invention, the determination of whether or not the surface (α) of the resin layer has an “indeterminate” recess or flat surface is determined from the surface (α) side of the resin layer, In principle, the shape of the recess is determined by visual observation or observation with a digital microscope (magnification: 30 to 100 times).
When using a digital microscope, for example, as shown in FIG. 4 (a), the focal point is gradually moved in the A direction from above a portion where a flat surface is supposed to be present on the surface (α) 12a. However, it is appropriate to observe the first focused portion as a flat surface.
If the focal point cannot be determined by the above method, as shown in FIG. 4B, a translucent adherend 100 having a smooth surface 100a on the surface (α) 12a of the resin layer is provided as much as possible. Paste with a squeegee so as not to apply a load, and observe the surface (α) 12a of the resin layer through the translucent adherend 100 using a digital microscope from the W direction. You may judge by the method of confirming whether it exists.
That is, the portion of the surface (α) that contacts the smooth surface 100a can be determined as a “flat surface”, and the portion of the surface (α) that does not contact the smooth surface 100a can be determined as a “concave portion”.

However, 1 to 10 regions (D) surrounded by a rectangle of 8 mm vertically and 10 mm horizontally selected on the surface (α) are selected, and a recess or flat surface existing in each selected region (D) The shape of the surface may be judged by visual observation or observation with a digital microscope (magnification: 30 to 100 times) from the surface (α) side. That is, in any selected region, if there is an irregular recess or flat surface, it can be regarded as “the surface (α) has an irregular recess or flat surface”. Similarly, in any of the selected regions, if there are a plurality of irregularly shaped recesses or flat surfaces, it can be regarded as “a plurality of irregularly shaped recesses 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.
In addition, the selected region (D) may be observed at a high magnification using a digital microscope. However, since the observation is performed at a high magnification, the region (D) is larger than the imageable region of the digital microscope. There is a case. In such a case, by using the image linking function of the digital microscope, a plurality of images adjacent to each other, which are arbitrarily selected, are acquired, and the plurality of images are connected to form a connected image. A portion surrounded by a rectangle of 8 mm in length and 10 mm in width 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 the selected area is observed using a digital microscope, the requirement is satisfied from the connected image in the same manner as described above. It may be determined whether or not.
That is, in this invention, it exists in the area | region (D) enclosed by the rectangle of 8 mm x 10 mm in width arbitrarily selected on the surface ((alpha)) and the recessed part and flat surface which exist on the surface ((alpha)) of a resin layer. The determination of whether or not each requirement regarding the concave portion and the flat surface to be satisfied and the calculation of various measured values (area, perimeter, etc.) regarding the concave portion, the flat surface, and the flat surface (R) are performed on the surface of the resin layer. The region (D) can be obtained from an image obtained using a digital microscope (magnification: 30 to 100 times) from the (α) side.

In the description of the present specification, examples of the digital microscope used when observing various shapes include the product names “Digital Microscope VHX-1000” and “Digital Microscope VHX-5000” manufactured by Keyence Corporation. Can be mentioned.
Further, when observing various shapes, a method of directly observing the surface (α) with a digital microscope at the above magnification may be used. A method of visually observing the shape of the concave portion and the flat portion may be used.

Moreover, it is preferable that the shape of the irregular recessed part which exists in the surface ((alpha)) can be visually recognized from the surface ((alpha)) 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, in the adhesive sheets 2a and 2b in which the release material 22 is laminated on the surface (α) 12a of the resin layer 12 as shown in FIG. 1C or 1D, when the release material 22 is removed. The exposed surface (α) 12a is visually observed.

In one embodiment of the present invention, the surface (α) may have a regular recess as well as an irregular recess 13 as shown in FIG.
However, the area ratio of the irregular recesses existing on the surface (α) to the total area 100% of recesses existing 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%.

  In one embodiment of the present invention, the area ratio occupied by the recesses existing on the surface (α) with respect to 100% of the total area of the surface (α) is preferably 10 to 80%, more preferably 20 to 70%, More preferably, it is 30 to 60%, and still more preferably 35 to 55%.

Similarly, in one embodiment of the present invention, a regular flat surface may exist on the surface (α) together with the irregular flat surface 14 as shown in FIG.
However, the area ratio of the irregular flat surface existing on the surface (α) 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%, and still more preferably 100%.

  In one embodiment of the present invention, the area ratio of the flat surface existing on the surface (α) to the total area 100% of the surface (α) is preferably 20 to 90%, more preferably 30 to 80%. More preferably, it is 40 to 70%, and still more preferably 45 to 65%.

In addition, said "area ratio which a recessed part or a flat surface occupies" acquires the image of surface ((alpha)) using a digital microscope (magnification: 30-100 times), and performs image processing (binary value) with respect to the said image. Calculation).
Moreover, the area | region (D) enclosed by the rectangle of 8 mm long * 10 mm wide arbitrarily selected on the surface ((alpha)) is selected 1-10 area | regions, Using a digital microscope (magnification: 30-100 times), Obtain an image of the area, calculate the value of “area ratio occupied by the recess or flat surface” of each area from the image, and calculate the average of the values of the selected 1 to 10 areas as the resin of the target adhesive sheet It can also be regarded as the “area ratio occupied by the recess or flat surface” present on the surface (α) of the layer.

  In one aspect of the present invention, from the viewpoint of forming a pressure-sensitive adhesive sheet with various properties such as air leakage and pressure-sensitive adhesive properties improved in a 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 that it does not have a shape that becomes a repeating unit.

Moreover, in one aspect of the present invention, from the viewpoint of a pressure-sensitive adhesive sheet in which various characteristics such as air escape and pressure-sensitive adhesive properties are improved in a balanced manner, there are a plurality of concave portions on the surface (α) of the resin layer, It is preferable that the position where a recessed part exists does not have periodicity. From the same viewpoint, it is preferable that the positions of a plurality of flat surfaces present on the surface (α) of the resin layer have no periodicity.
In the present invention, “the position where a plurality of recesses or flat surfaces are present has no periodicity” means that the positions where the plurality of recesses or flat surfaces exist are the same on the surface (α) of the resin layer. It means an irregular (random) state without a pattern.

  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 constant repeating unit”, and “the position where the plurality of concave portions or the flat surface exists does not have periodicity”. This determination can be made by the same method as the above-described determination method of “whether there is an irregular recess or flat surface on the surface (α) of the resin layer”.

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

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

In one embodiment of the present invention, the recess 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 area.

FIG. 3 is a schematic cross-sectional view of the resin layer showing an example of the shape on the surface (α) side of the resin layer of the pressure-sensitive adhesive sheet of the present invention.
As the recess 13 shown in FIG. 3 (a), the shape of the conventional recess, 2 Tsunoyama part _(M 1), having a _{(M 2),} and a valley portion (N). In the present invention, the “maximum height difference” of the recess is the highest position (m) of the two peak portions (M ₁ ) and (M ₂ ) with respect to the thickness direction of the resin layer 12 (FIG. 3A ) Means the length of the difference (h) between the peak portion (M ₁ ) maximum point) and the lowest position (n) (the minimum point of the valley portion (N) in FIG. 3A).
In the case of FIG. 3B, a recess 131 having two peak portions (M ₁₁ ) and (M ₁₂ ) and a valley portion (N ₁ ), two peak portions (M ₁₂ ), and _{(M 13),} is believed to have two recesses of the recess 132 having a valley portion _{(N 2).} In this case, the length of the difference (h ₁ ) between the maximum point of the peak portion (M ₁₁ ) and the minimum point of the valley portion (N ₁ ) represents the maximum height difference of the recess 131, and the maximum of the peak portion (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 recess 132.

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

Moreover, as an average value of the width | variety of the said recessed part, from a viewpoint of the improvement of the air release property of an adhesive sheet, and a viewpoint which makes the adhesiveness of an adhesive sheet favorable, Preferably it is 1-500 micrometers, More preferably, it is 3-400 micrometers. Preferably it is 5-300 micrometers.
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. The distance L with respect to (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 with the part (M ₁₂ ).
In addition, when the pressure-sensitive adhesive sheet of the present invention is viewed in plan (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 width of the single recess [maximum height difference / width average value] (in the recess 13 shown in FIG. 3A, "h / L" is indicated) Is preferably 1/500 to 100/1, more preferably 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 adhesive property of the pressure-sensitive adhesive sheet. 1/60 to 10/1.

  In the present invention, the maximum height difference of the recesses and the width of the recesses can be measured by observing with a scanning electron microscope (magnification: 100 to 1000 times), but determined from an image acquired using a scanning electron microscope. May be.

<Special 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 a diameter of 150 μm, more preferably a diameter of 200 μm) on the surface (α) of the resin layer. ) Is preferably present, more preferably a plurality of the flat surfaces (f1).
Since the surface (α) has a flat surface (f1), the adhesion portion with the adherend on the surface (α) is sufficient, so that the adhesion with the adherend can be improved, and more It can be set as the adhesive sheet with high adhesive force.
Further, in the above-described embodiment of the present invention, one flat surface (f1) is formed in the region (D) surrounded by a rectangle of 8 mm long × 10 mm wide arbitrarily selected on the surface (α) of the resin layer. It is preferable that the above exist, and it is more preferable that a plurality of flat surfaces (f1) exist.
In the above-described embodiment, it is not necessary that all the flat surfaces existing on the surface (α) or the region (D) of the resin layer correspond to the flat surface (f1), and the surface (α) or the region ( The flat surface which exists in D) should just contain 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) on the surface (α) of the resin layer. It is preferable that one or more (f2) exists, and it is more preferable that a plurality of flat surfaces (f2) exist.
Since the flat surface (f2) is present on the surface (α), the adhesion part with the adherend on the surface (α) is sufficient, so that the adhesion with the adherend can be improved, It can be set as the adhesive sheet with high adhesive force.
Moreover, in the said aspect of this invention, in the area | region (D) enclosed by the rectangle of 8 mm long x 10 mm wide arbitrarily selected on the surface ((alpha) of a resin layer, one or more flat surfaces (f2) are included. It is preferable to exist, and it is more preferable that a plurality of the flat surfaces (f2) exist.
In the above-described embodiment, the entire flat surface existing on the surface (α) or the region (D) of the resin layer does not have to correspond to the flat surface (f2), and the surface (α) or region ( The flat surface which exists in D) should just contain a flat surface (f2).

  Further, in the region (D) surrounded by a rectangle (8 mm long × 10 mm wide) arbitrarily selected on the surface (α) or the surface (α) of the resin layer, the flat surfaces (f1) and (f2) described above It is preferable that at least one corresponding flat surface (f12) exists in both cases, and it is more preferable that a plurality of the flat surfaces (f12) exist.

  In the present invention, whether or not the above-described flat surfaces (f1), (f2), and (f12) are present on the surface (α) or the region (D) is determined by the resin layer of the target adhesive sheet. An image obtained by observing a flat surface existing on the surface (α) or region (D) of the sample using a digital microscope (magnification: 30 to 100 times), and using the image analysis software based on the image, the diameter You may judge whether the area | region enclosed by the 100-200 micrometers circle is selectable, and may calculate the area of a flat surface.

In one aspect of the present invention, in a region (D) surrounded by a rectangle of 8 mm long × 10 mm wide arbitrarily selected on the surface (α) of the resin layer, the total area of the recesses present in the region (D) It is preferable that there is a recess having an area of 70 to 99.99% (more preferably 85 to 99.99%) with respect to 100%.
Due to the presence of such a continuous recess, the pressure-sensitive adhesive sheet can be further improved in air bleeding.

<Requirement (I): Average value of ratio (L / S) of one or more flat surfaces (R)>
The pressure-sensitive adhesive sheet of the present invention has a plurality of flat surfaces in a region (D) surrounded by a rectangle of 8 mm long × 10 mm wide arbitrarily selected on the surface (α) and satisfies the following requirement (I): .
Requirement (I): One or more of the plurality of flat surfaces existing in the region (D) excluding a flat surface having a cumulative relative frequency of 30% or less obtained by adding a relative frequency from the smaller area of each flat surface The average value of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] of each flat surface (R) is 0.011 to. 020.

  The “flat surface (R)” defined in the above requirement (I) is the cumulative relative frequency 30 obtained by adding the relative frequencies from the smaller surface area of all the flat surfaces existing in the region (D). It refers to the remaining flat surface excluding the flat surface of less than%.

In the present invention, in the requirement (I) and requirements (II) and (III) described later, from the plurality of flat surfaces existing in the region (D), “accumulation obtained by adding the relative frequency from the smaller area of each flat surface The reason for targeting one or more flat surfaces (R) excluding “a flat surface having a relative frequency of 30% or less” is as follows.
That is, when an image of a region (D) surrounded by a rectangle of 8 mm in length and 10 mm in width arbitrarily selected by a digital microscope is acquired, a flat surface (in FIG. 2) approaches the end of the region (D). The flat surface 14 ′) may be cut by four sides of a rectangle 50 that is 8 mm long × 10 mm wide, which is the boundary line of the region (D). For example, also in FIG. 2, it can be seen that there are a plurality of flat surfaces 14 ′ cut by the four sides of the rectangle 50 that is the boundary line of the region (D).
A “cut flat surface” such as the flat surface 14 ′ intersects the rectangle 50, which happens to be a boundary line of the region (D), depending on how the region (D) is selected, and is cut in the region (D). The flat surface has a reduced area, and is not a flat surface that actually exists on the surface (α).
Thus, from the data of the area of the flat surface including the flat surface 14 'cut by the four sides of the rectangle 50 that is the boundary line of the region (D), the requirement (I) and the requirement (II) described later are obtained. Even if the value defined in (III) is calculated, there is a concern that if the influence of the data on the flat surface 14 ′ that does not actually exist becomes large, the data will be different from the actual state.
By the way, most of “the flat surface 14 ′ cut by the rectangle that is the boundary line of the region (D)” is “a flat surface having a cumulative relative frequency of 30% or less obtained by adding the relative frequencies from the smaller area of each flat surface. "include.
Therefore, in the present invention, for all flat surfaces existing in the region (D), the values specified in the requirements (I) to (III) are not calculated, but the flat surfaces existing in the region (D). From “the flat surface (R)” excluding “a flat surface with a cumulative relative frequency of 30% or less obtained by adding the relative frequency from the smaller area of each flat surface”, the values specified in the requirements (I) to (III) Is the calculation target. Thereby, the influence on the values defined in the requirements (I) to (III) exerted by the “flat surface 14 ′ cut by the rectangle 50 that is the boundary line of the region (D)” that does not actually exist is reduced. It is adjusted.

In the present invention, as defined in the requirement (I), the average value of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] of each flat surface (R) is 0.011 to 0.020.
That is, the average value is a value calculated from the following formula (1).

（上記式（１）中、Ｓは、対象となる１個の平坦面（Ｒ）の面積（単位：μｍ^２）、Ｌは、当該平坦面（Ｒ）の周囲長（単位：μｍ）であり、ｎは選択した領域（Ｄ）内に存在する平坦面（Ｒ）の個数を示す。μは、領域（Ｄ）内に存在する平坦面（Ｒ）の上記比（Ｌ／Ｓ）の平均値を示す。）

(In the above formula (1), S is the area (unit: μm ² ) of one target flat surface (R), and L is the perimeter (unit: μm) of the flat surface (R). , N represents the number of flat surfaces (R) existing in the selected region (D), and μ is an average value of the ratio (L / S) of the flat surfaces (R) present in the region (D). Is shown.)

The average value of the ratio (L / S) is an index that represents the degree of intricacy of the shape of the flat surface and the recess existing on the surface (α) of the resin layer of the pressure-sensitive adhesive sheet.
That is, a flat surface having a large ratio (L / S) indicates a flat surface having a complicated shape. When the average value of the ratio (L / S) increases, it can be said that a flat surface having such a complicated shape exists in the selected region (D).
For example, when comparing two flat surfaces having different perimeter lengths (L) with the same flat surface area (S), the larger perimeter length (L) means that the boundary length between the flat surface and the recess is longer. Indicates that it is longer and represents the complexity of the shape with more complicated boundaries.
That is, since there are many flat surfaces having a complicated shape, the shape of the concave portion serving as the air discharge passage becomes complicated in conjunction with it.

Therefore, the larger the average value of the ratio (L / S), the more flat surfaces having a complicated shape exist in the selected region (D). As a result, the concave portion serving as an air discharge passage is formed. It is distributed in a complicated manner.
As a result, when the resin layer of the pressure-sensitive adhesive sheet is affixed to the adherend, the liquid can enter the interface between the surface (α) of the resin layer and the adherend while exhibiting good air bleedability. Excellent liquid resistance that can be effectively prevented is exhibited.
In the present specification, “liquid” refers to a substance having fluidity at room temperature (25 ° C.) and refers to water, an organic solvent, or the like. The adhesive sheet of the present invention is particularly attached to an adherend. In this case, an excellent effect in terms of water resistance that can suppress the entry of “water” that can enter the interface with the adherend is exhibited.

In the present invention, as defined in the requirement (I), the average value of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] of each flat surface (R) is 0. 0.011 to 0.020.
When the average value of the ratio (L / S) is less than 0.011, the ratio of the concave portions having a simple shape tends to increase in the region (D). The liquid resistance is poor.
On the other hand, when the average value of the ratio (L / S) exceeds 0.020, it is difficult to form a recess having a width and length sufficient to serve as an air discharge passage, and the air in the resulting adhesive sheet Detachability is inferior.

From the above viewpoint, the average value of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] of each flat surface (R) defined in the requirement (I) is From the viewpoint of improving liquidity, it is preferably 0.012 or more, more preferably 0.013 or more, still more preferably 0.014 or more, and still more preferably 0.015 or more. From the viewpoint, it is preferably 0.019 or less, more preferably 0.018 or less, still more preferably 0.0175 or less, and still more preferably 0.017 or less.

<Requirement (II): Skewness Sk value>
In the pressure-sensitive adhesive sheet of one embodiment of the present invention, it is preferable that the following requirement (II) is further satisfied from the viewpoint of making a pressure-sensitive adhesive sheet with improved air bleeding and liquid resistance in a balanced manner.
Requirement (II): For a normal distribution curve of the ratio (L / S) and frequency of the area (S) [μm ² ] and the perimeter (L) [μm] of each of one or more flat surfaces (R) The skewness Sk value is -0.1 to 1.6.

In the present invention, the “skewness Sk value” defined in the requirement (II) means statistically the degree of asymmetry with respect to the normal distribution curve of the ratio (L / S) and frequency of the flat surface (R). Represent.
If the skewness Sk value = 0, the ratio (L / S) of the flat surface (R) and the frequency distribution curve are symmetric.
If the skewness Sk value> 0 (the skewness Sk value is a positive value), the distribution curve of the ratio (L / S) and frequency of the flat surface (R) is biased to the left, and the tail of the distribution curve The shape extends to the right.
If the skewness Sk value <0 (the skewness Sk value is negative), the distribution curve of the ratio (L / S) and frequency of the flat surface (R) is biased to the right, and the tail of the distribution curve The shape extends to the left.
Moreover, it shows that distortion increases as the absolute value of the skewness Sk value increases.

  In one embodiment of the present invention, the “strain Sk value” defined in requirement (II) is preferably −0.1 to 1.6, more preferably −0.09 to 1.57, Preferably it is -0.085 to 1.55, More preferably, it is -0.08 to 1.53, More preferably, it is 0.01 to 1.53.

  In the present invention, the skewness Sk value for the normal distribution curve of the ratio (L / S) and frequency of each of one or more flat surfaces (R) is calculated based on the following formula (2). (Company, Excel).

〔式（２）中、ｎは平坦面（Ｒ）の個数、ｘ_ｉは、各平坦面（Ｒ）の各々の前記比（Ｌ／Ｓ）（ｉ：１，２，・・・ｎ）、μは各平坦面（Ｒ）の前記比（Ｌ／Ｓ）の平均値、ｓは標本標準偏差を示す。〕

[In Formula (2), n is the number of flat surfaces (R), x _i is the ratio (L / S) of each flat surface (R) (i: 1, 2,... N), μ represents an average value of the ratio (L / S) of each flat surface (R), and s represents a sample standard deviation. ]

<Requirement (III): Difference between the maximum value and the median value of the ratio (L / S) of one or more flat surfaces (R)>
In the pressure-sensitive adhesive sheet of one embodiment of the present invention, it is preferable that the following requirement (III) is further satisfied from the viewpoint of making a pressure-sensitive adhesive sheet with improved air bleeding and liquid resistance in a balanced manner.
Requirement (III): The difference between the maximum value and the median value of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] of one or more flat surfaces (R) Is 0.0010 to 0.018.
The difference between the maximum value and the median value of the ratio (L / S) being 0.0010 or more indicates that there is a flat surface having a more complicated shape than others. Due to the presence of such a flat surface, the pressure-sensitive adhesive sheet can be further improved in air bleeding.

In one embodiment of the present invention, the difference between the maximum value and the median value of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] defined in requirement (III) , Preferably 0.0010 to 0.018, more preferably 0.0012 to 0.0175, and still more preferably 0.0014 to 0.0173.

In one embodiment of the present invention, from the viewpoint of forming a pressure-sensitive adhesive sheet in which a concave portion and a flat surface satisfying the above-mentioned requirements (I) to (III) are formed on the surface (α) of the resin layer, the concave portion is the self of the resin layer It is preferably formed by formation.
In the present invention, “self-forming” means a phenomenon that creates a disordered shape naturally in the autonomous formation process of the resin layer. It means a phenomenon that naturally forms a disordered shape in the autonomous formation process of the resin layer by drying the coated film.
In addition, the shape of the recess formed by self-forming the resin layer in this way can be adjusted to some extent by adjusting the drying conditions and the type and content of components in the composition that is the resin layer forming material. Although it is possible, it can be said that, unlike the groove formed by the transfer of the embossed pattern, “it is virtually impossible to reproduce the same shape”. Therefore, it can be said that the recessed part formed by self-formation of the resin layer is indefinite.
In addition, since the irregular concave portion is formed, the shape of the flat surface becomes irregular.

The formation process of the recess formed by the self-formation of the resin layer is considered as follows.
First, at the time of forming the coating film made of the composition that becomes the resin layer forming material, in the step of drying the coating film, shrinkage stress is generated inside the coating film, and the bonding strength of the resin is weakened. Cracks occur in the coating film. And it is thought that the resin around the cracked portion flows into the space temporarily generated by the cracking, so that a recess is formed on the surface (α) of the resin layer.
After forming two-layer coating films with different resin contents, the two-layer coating films are dried at the same time, resulting in a shrinkage stress difference inside the coating film and causing cracks in the coating film. It will be easier.

In addition, from the viewpoint of facilitating the formation of the concave portion, it is preferable to adjust the following matters as appropriate. It is considered that the factors due to these matters act in a complex manner and the concave portions are easily formed. By the way, the suitable aspect of each matter for making it easy to form a recessed part is as the description by the applicable item mentioned later.
-The type of resin, constituent monomer, molecular weight, and content contained in the composition that is the coating film forming material.
-The kind of crosslinking agent and the kind of solvent which are contained in the composition which is a film-forming material.
-Viscosity and solid content concentration of the composition which is a material for forming the coating film
-The thickness of the coating film to be formed. (In the case of multiple layers, the thickness of each coating film)
-Drying temperature and drying time of the formed coating film.

In the formation of the 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 release property of the pressure-sensitive adhesive sheet is intentionally formed. Is 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, when the composition contains fine particles, by adjusting the viscosity of the coating film composed of a composition containing many 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 moderately suppressed. By adjusting in this way, in the coating film containing a lot of resin, there is a tendency that cracks are generated in the horizontal direction and the concave portions are easily formed.
As a result, on the surface (α), the ratio of the recessed portions to be formed can be increased, and the ratio of the recessed portions connected to each other can be increased, so that a pressure-sensitive adhesive sheet having more excellent air release properties can be obtained.

Moreover, among the above matters, it is preferable to appropriately adjust the type, constituent monomer, molecular weight, and resin content of the resin so that the resin contained in the coating film containing a large amount of resin has appropriate viscoelasticity.
In other words, by appropriately hardening 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 part (X) becomes strong, and a recess is easily formed. Become. The harder the coating film, the stronger the shrinkage stress and the easier it is to generate recesses. Further, if the elasticity of the resin is increased too much, the adhesive strength of the resin layer formed from the coating film tends to decrease. Considering this point, it is preferable to appropriately adjust the viscoelasticity of the resin.
In addition, when the composition or coating film contains fine particles, by adjusting the dispersion state of the fine particles, the degree of swelling of the resin layer by the fine particles and the self-forming ability of the recesses can be adjusted, resulting in It is considered that the concave portion can be easily formed on the surface (α) and can be adjusted.

Furthermore, it is preferable to appropriately set the above items in consideration of the crosslinking rate of the formed coating film (or composition that is a forming material).
That is, when the crosslinking speed of the coating film is too high, the coating film may be cured before the recess is formed. It also affects the size of the cracks in the coating and the size of the recesses.
The crosslinking rate of the coating film can be adjusted by appropriately setting the type of the crosslinking agent and the solvent in the composition as the forming material, 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 resin and a particle portion (Y) made of fine particles, the resin layer formed by the above-described self-formation is shown in FIG. As shown in (d), the particle portion (Y) has such a distribution that the proportion of the particle portion (Y) is smaller than the others in the portion where the concave portion 13 exists on the surface (α). Tend to be.
This is because, in the process of self-forming the resin layer, when the recess is formed on the surface (α) of the resin layer, the fine particles that existed at the position where the recess was formed move. It is thought that it became distribution.

Hereinafter, each structure of the adhesive sheet of this invention is demonstrated.
〔Base material〕
The substrate used in one embodiment of the present invention is not particularly limited, and examples thereof include a paper substrate, a resin film or sheet, a substrate obtained by laminating a paper substrate with a resin, and the like. It can select suitably according to the use of a sheet | seat.
Examples of the paper constituting the paper substrate 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 such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer. Polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; urethane resin such as polyurethane and acrylic modified polyurethane; polymethylpentene; Polysulfone; Polyetheretherketone; Polyethersulfone; Polyphenylene sulfide; Polyimide resins such as polyetherimide and polyimide; Polyamide resins, acrylic resins, fluorine-based resins.
Examples of the base material obtained by laminating a paper base material with a resin include laminated paper obtained by laminating the paper base material 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 still more preferable.
In addition, when the pressure-sensitive adhesive sheet of the present invention is used for an application requiring heat resistance, a film or sheet composed of a resin selected from polyethylene naphthalate and a polyimide resin is preferable, and an application requiring weather resistance. When used in a film, a film or sheet composed of a resin selected from polyvinyl chloride, polyvinylidene chloride, acrylic resin, and fluororesin is preferable.

Although the thickness of a base material is suitably set according to the use of the adhesive sheet of this invention, from a viewpoint of handleability and economical efficiency, Preferably it is 5-1000 micrometers, More preferably, it is 10-500 micrometers, More preferably, 12- The thickness is 250 μm, more preferably 15 to 150 μm.
In addition, 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 colorant.

In addition, the base material used in one embodiment of 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, and specifically, the surface of the above-described resin film or sheet. A substrate having a metal layer thereon is preferred.
Examples of the metal contained in the metal layer include metals having metallic luster such as aluminum, tin, chromium, and titanium.
As a method for forming the metal layer, for example, a method of depositing the metal 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.

Furthermore, when using a resin film or sheet as the base material, from the viewpoint of improving the adhesion with the resin layer laminated on these resin films or sheets, the surface of the resin film or sheet is oxidized or uneven. Surface treatment by a method or the like, or primer treatment may be performed.
Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), hot air treatment, ozone, and ultraviolet irradiation treatment. Examples of the unevenness method include sand blast method and solvent treatment method. Etc.

[Release material]
As a release material used in one embodiment of 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. Can be mentioned.
In addition, the said peeling process surface does not have uneven | corrugated shape, and the peeling material (for example, the peeling material in which the embossing pattern is not given) which is flat is preferable.
Examples of the base material for the release material include the above-described paper base material, resin film or sheet used as the base material included in the pressure-sensitive adhesive sheet of one embodiment of the present invention, and a base material obtained by laminating a paper base material with a resin. It is done.
Examples of the release agent include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long chain alkyl resins, alkyd resins, and fluorine resins.
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 included in the pressure-sensitive adhesive sheet of the present invention preferably includes a resin part (X) containing a resin and a particle part (Y) made of fine particles.
The resin part (X) indicates a part containing components other than the fine particles contained in the resin layer. That is, not only the resin but also components other than fine particles, such as a tackifier, a crosslinking agent, and a general-purpose additive, 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 part (Y) in the resin layer, the shape maintaining property after sticking can be improved, and when the obtained pressure-sensitive adhesive sheet is used at 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, it may be configured to be divided into a part mainly composed of the resin part (X) and a part mainly composed of the particle part (Y).

It is preferable that the resin layer which the adhesive sheet of 1 aspect of this invention has has a space | gap part (Z) further besides resin part (X) and particle | grain part (Y). By having a 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 that exist between the fine particles, and voids that exist in the secondary particles when the fine particles are secondary particles.
When the resin layer has a multilayer structure, the resin portion (X) flows into the void portion (Z) even if the void portion (Z) exists immediately after the formation of the resin layer or immediately after the formation. In some cases, the voids disappear and the resin layer has no void portion (Z).
However, even when the void portion (Z) that 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 recess on the surface (α) of the resin layer. Therefore, the air release property is good, and the resin layer has a particle portion (Y), so that the blister resistance is also excellent.

In addition, the shear storage elastic modulus at 100 ° C. of the resin layer included in the pressure-sensitive adhesive sheet of one embodiment of the present invention is preferably 9.0 × 10 ³ Pa or more from the viewpoint of improving the air release property and blister resistance of the pressure-sensitive adhesive sheet. More preferably, it is 1.0 × 10 ⁴ Pa or more, and further 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, 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 opposite to the side on which the base material or release material is provided has adhesiveness, but the base material or release material is provided. The surface (β) of the resin layer on the side may also have adhesiveness.

The adhesive force on the surface (α) of the resin layer of the pressure-sensitive adhesive sheet of one embodiment 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. More preferably, it is 4.0 N / 25 mm or more, and still more preferably 7.0 N / 25 mm or more.
Further, 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>
As a resin layer, the multilayer structure comprised from 2 or more types of layers may be sufficient.
As a resin layer which is such a multilayer structure, a layer (Xβ) mainly including a resin portion (X) from the side where a base material or a release material is provided, such as the adhesive sheet 1a of FIG. A multilayer structure in which a layer (Y1) containing 15% by mass or more of the particle part (Y) and a layer (Xα) mainly containing the resin part (X) are laminated in this order can be given.
In addition, in the structure of the multilayer structure of the resin layer, the boundary between the two layers to be laminated may not be discriminated, and a mixed layer may be used.
That is, in the resin layer 12 included in the pressure-sensitive adhesive sheet 1a in 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. A mixed layer structure may be used.

  Hereinafter, the resin layer 12 composed of three layers of the layer (Xβ), the layer (Y1), and the layer (Xα) included in 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 a particle portion (Y). However, the content of the particle part (Y) in the layer (Xβ) and the layer (Xα) is each independently 15 masses 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 include the above-described void portion (Z) in addition to the resin portion (X) and the particle portion (Y).

As content of the resin part (X) in a layer (X (beta)) and a layer (X (alpha)), it is 85 mass normally with respect to the total mass (100 mass%) of a layer (X (beta)) or a layer (X (alpha)) each 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.
In addition, said "content of resin part (X)" is resin, a tackifier, a crosslinking agent, and general-purpose addition which comprises the resin part (X) contained in a layer (X (beta)) or a layer (X (alpha)). 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 independently from the total mass (100% by mass) of the layer (Xβ) or the layer (Xα). However, it is 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 layer (Xβ) or the forming material of the layer (Xα). However, it can also be regarded as the content of fine particles in a)) excluding a diluting solvent.

As content of resin in a layer (X (alpha)), it is 30-100 mass% normally with respect to the total mass (100 mass%) of a layer (X (alpha)), Preferably it is 40-100 mass%, More preferably, it is 50-100. It is 60 mass%, More preferably, it is 60-100 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, and more preferably 75% with respect to the total mass (100% by mass) of the layer (Xβ). -100 mass%, More preferably, it is 85-100 mass%.
In addition, in this invention, "content of the resin in a layer (X (beta)) and a layer (X (alpha))""is the whole quantity (100 mass% (100 mass% ( However, it can be regarded as the content of the resin in (excluding the diluting solvent))).

In the pressure-sensitive adhesive sheet of one embodiment of the present invention, the layer (Xα) preferably contains a tackifier as the resin component (X) from the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive sheet.
On the other hand, when the pressure-sensitive adhesive sheet of the present invention has a substrate, the content of the tackifier in the layer (Xβ) is the total mass of the layer (Xβ) from the viewpoint of improving the adhesion between the substrate and the resin layer. It is preferable that it is 0-10 mass% with respect to (100 mass%), and it is more preferable that it is 0-5 mass%.

The layer (Y1) may be a layer composed only of the particle part (Y), may be a layer containing the resin part (X) together with the particle part (Y), and further has a void part (Z). It may be.
The content of the fine particles constituting the particle portion (Y) in the layer (Y1) is 15% by mass or more with respect to the total mass (100% by mass) of the layer (Y1), preferably 20 to 100. The mass% is more preferably 25 to 90 mass%, still more preferably 30 to 85 mass%, and still more preferably 35 to 80 mass%.

  As content of resin in a layer (Y1), it is 0-85 mass% normally with respect to the total mass (100 mass%) of a layer (Y1), Preferably it is 1-80 mass%, More preferably, it is 5-75. It is 10 mass%, More preferably, it is 10-70 mass%, More preferably, it is 20-65 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% by mass) of the composition that is a forming material of the layer (Y1). % (Excluding the diluting solvent)) can be regarded as the content of fine particles or resin.

In one embodiment of the present invention, the layer (Xα) is preferably a layer formed of a composition (xα) containing a resin and containing a fine particle of less than 15% by mass.
Similarly, the layer (Xβ) is also preferably a layer formed of a composition (xβ) containing a resin and containing a fine particle of less than 15% by mass.
The layer (Y1) is preferably a layer formed from the composition (y) containing 15% by mass or more of fine particles.
In addition, about a suitable aspect (a content component, content, etc.) of a composition (x (alpha)), a composition (x (beta)), and a composition (y1), it is as below-mentioned.

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

The resin content in the resin part (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 part (X). More preferably, it is 55 mass% or more, More preferably, it is 60 mass% or more, More preferably, it is 70 mass% or more, Preferably it is 100 mass% or less, More preferably, it is 99.9 mass% or less.
In the present invention, the value of the content of the resin in the resin composition 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 expressing the adhesiveness on the surface (α) of the formed resin layer.
In particular, as in the pressure-sensitive adhesive sheet 1a in FIG. 1A, the layer (Xβ), the layer (Y1), and the layer (Xα) are arranged in this order from the side on which the base material or release material is provided. From the above viewpoint, at least the layer (Xα) preferably contains an adhesive resin. Moreover, it is preferable that at least the layer (Xα) and the layer (Xβ) contain an adhesive resin from the viewpoint of configuring the double-sided pressure-sensitive adhesive sheet and improving the adhesion to the base material.

Examples of the adhesive resin include acrylic resins, urethane resins, rubber resins, and silicone resins.
Among these adhesive resins, it is preferable to include an acrylic resin from the viewpoint of good adhesive properties and weather resistance and facilitating formation of recesses 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% with respect to the total amount (100% by mass) of the resin contained in the resin part (X). -100 mass%, More preferably, it is 80-100 mass%, More preferably, it is 100 mass%.

Moreover, from the viewpoint of facilitating the formation of the recesses 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 in FIG. 1A, the layer (Xβ), the layer (Y1), and the layer (Xα) are arranged in this order from the side on which the base material or release material is provided. From the above viewpoint, at least the layer (Y1) preferably contains a resin having a functional group.
The functional group is a group that is 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 part (X) preferably further contains a crosslinking agent together with the resin having the functional group. In particular, when the resin layer is the multilayer structure described above, 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.

  Examples of the isocyanate-based crosslinking agent include 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; In addition, biuret bodies, isocyanurate bodies of these compounds, and adduct bodies that are a reaction product of low molecular active hydrogen-containing compounds (ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, etc.); Is mentioned.

  Examples of the epoxy-based cross-linking agent include ethylene glycol glycidyl ether, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, Examples include 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidyl amine and the like.

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

Examples of the metal chelate-based cross-linking agent include chelate compounds whose metal atoms are aluminum, zirconium, titanium, zinc, iron, tin, etc., but from the viewpoint of facilitating formation of recesses and flat surfaces on the surface (α) of the resin layer. Therefore, an aluminum chelate-based crosslinking agent is preferable.
Examples of the aluminum chelate-based crosslinking agent include diisopropoxy aluminum monooleyl acetoacetate, monoisopropoxy aluminum bis oleyl acetoacetate, monoisopropoxy aluminum monooleate monoethyl acetoacetate, diisopropoxy aluminum monolauryl acetoacetate, Examples include isopropoxyaluminum monostearyl acetoacetate and diisopropoxyaluminum monoisostearyl acetoacetate.

In addition, you may use these crosslinking agents individually or in combination of 2 or more types.
Among these, it is preferable that the resin part (X) contains at least one selected from a metal chelate-based crosslinking agent and an epoxy-based crosslinking agent from the viewpoint of facilitating formation of a recess in the surface (α) of the resin layer. It is more preferable to include a metal chelate crosslinking agent, and it is even more preferable to include an aluminum chelate crosslinking agent.

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

Moreover, as one aspect of the present invention, it is preferable that the resin portion (X) contains both a metal chelate-based crosslinking agent and an epoxy-based crosslinking agent from the viewpoint of facilitating formation of recesses on the surface (α) of the resin layer. .
When the resin part (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 and the epoxy crosslinking agent in the resin part (X) [metal chelate system The cross-linking agent / epoxy-based cross-linking agent] is preferably 10/90 to 99.5 / 0.5, more preferably 50/50 to 99.0 / 1.0, and still more preferably 65/35 by mass ratio. To 98.5 / 1.5, more preferably 75/25 to 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 is the above-described multilayer structure, the layer (Xα) preferably contains an adhesive resin and a tackifier.

In addition, the tackifier used by this invention is a component which improves the adhesive force of an adhesive resin auxiliary, Comprising: The mass mean molecular weight (Mw) points out the oligomer below usually 10,000, and the above-mentioned adhesive resin and Are distinct.
The mass average molecular weight (Mw) of the tackifier is preferably 400 to 8000, more preferably 5000 to 5000, and more preferably 800 to 3500.

Examples of tackifiers include rosin resins such as rosin resins, rosin ester resins, and rosin-modified phenol resins; hydrogenated rosin resins obtained by hydrogenating these rosin resins; Terpene resins such as styrene resins; hydrogenated terpene resins obtained by hydrogenating these terpene resins; styrene obtained by copolymerizing a styrene monomer such as α-methylstyrene or β-methylstyrene with an aliphatic monomer Hydrogenated styrene resins obtained by hydrogenating these styrene resins; C5 systems obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine, 1.3-pentadiene produced by thermal decomposition of petroleum naphtha Petroleum resin and hydrogenated petroleum resin of this C5 petroleum resin; indene and vinyli produced by thermal decomposition of petroleum naphtha And C9 petroleum resins obtained by copolymerizing C9 fractions such as toluene and hydrogenated petroleum resins.
The tackifiers used in the present invention may be used alone or in combination of two or more different softening points and structures.

The softening point of the tackifier is preferably 80 ° C or higher, more preferably 80 to 180 ° C, still more 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 K2531.
Moreover, when using 2 or more types of several tackifier, it is preferable that the weighted average of the softening point of these several tackifier belongs to the said range.

  When the tackifier is contained in the resin part (X), the content of the tackifier is preferably 1 part by mass or more with respect to 100 parts by mass of the adhesive resin contained in the resin part (X). Preferably it is 1-200 mass parts, More preferably, it is 3-150 mass parts, More preferably, it is 5-90 mass parts.

Moreover, the resin part (X) may contain general-purpose additives other than the above-mentioned crosslinking agents and tackifiers.
General-purpose additives include, for example, antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction accelerators, ultraviolet absorbers, and the like.
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 with respect to 100 parts by mass of the resin. .

The said resin contained in resin part (X) may be only 1 type, and may be used in combination of 2 or more type.
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 (below) It is more preferable that it is an acrylic pressure-sensitive adhesive containing simply an “acrylic resin (A)”, and it is an acrylic pressure-sensitive adhesive containing an acrylic resin (A) having a functional group and a crosslinking agent (B). More preferably.
The acrylic pressure-sensitive adhesive may be either a solvent type or an emulsion type.
Hereinafter, the above-mentioned acrylic pressure-sensitive adhesive suitable for the resin part (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 ( Examples thereof include a polymer having a structural unit derived from (meth) acrylate.
The mass average molecular weight (Mw) of the acrylic resin (A) is preferably 50,000 to 1,500,000, more preferably 150,000 to 1,300,000, still more preferably 250,000 to 1,100,000, still more preferably 350,000 to 90. 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 the 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 adhesive. It is 80 mass%, More preferably, it is 80-100 mass%, More preferably, it is 90-100 mass%.
In addition, the form 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.

As carbon number of the alkyl group which a monomer (a1 ') has, from a viewpoint of the improvement of an adhesive characteristic, More preferably, it is 4-12, More preferably, it is 4-8, More preferably, it is 4-6.
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 ( Examples include meth) acrylate and stearyl (meth) acrylate.
Among these, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable, and butyl (meth) acrylate is more preferable.

  The content of the structural unit (a1) is preferably 50 to 99.5% by mass, more preferably 60 to 99% by mass, with respect to the total structural unit (100% by mass) of the acrylic copolymer (A1). More preferably, it is 70-95 mass%, More preferably, it is 80-93 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, itaconic acid, and (meth) acrylic acid is preferred.

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

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 the total structural unit (100% by mass) of the acrylic copolymer (A1). Is 0 to 10% by mass, more preferably 0 to 5% by mass.
In addition, you may use the above-mentioned monomer (a1 ')-(a3') individually or in combination of 2 or more types.

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

Examples of the cross-linking agent (B) contained in the acrylic pressure-sensitive adhesive include those described above. From the viewpoint of improving the pressure-sensitive adhesive property, and the viewpoint of easily forming a recess on the surface (α) of the resin layer. Therefore, it is preferable to include one or more selected from a metal chelate-based crosslinking agent and an epoxy-based crosslinking agent, more preferably a metal chelate-based crosslinking agent, and still more preferably an aluminum chelate-based crosslinking agent.
Moreover, as one aspect of the present invention, as a crosslinking agent (B), a metal chelate-based crosslinking agent and an epoxy-based crosslinking are used from the viewpoint of improving the shape maintainability of a plurality of recesses present on the surface (α) of the resin layer. It is preferable to include both agents.

  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 with respect to 100 parts by mass of the acrylic resin (A) in the acrylic adhesive. More preferably, it is 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 chelate crosslinking agent and the epoxy crosslinking agent [metal chelate crosslinking agent / epoxy crosslinking agent] is preferably a mass ratio, preferably 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, still more preferably 75/25 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.

  Moreover, it is preferable that the acrylic adhesive used in one embodiment of the present invention further contains a tackifier from the viewpoint of further improving the 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.

In the acrylic pressure-sensitive adhesive used in one embodiment of the present invention, a pressure-sensitive resin other than the acrylic resin (A) (for example, urethane-based resin, rubber-based resin, silicone-based resin, etc.) within a range not impairing the effects of the present invention. ) 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%, based on the total amount (100% by mass) of the adhesive resin contained in the acrylic pressure-sensitive adhesive. -100 mass%, More preferably, it is 80-100 mass%, More preferably, it is 100 mass%.

<Particle part (Y)>
In the resin layer which the adhesive sheet of 1 aspect of this invention has, it is preferable that the particle part (Y) which consists of microparticles | fine-particles is included.
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 the concave portion and the flat surface on the surface (α) of the resin layer. It is -100 micrometers, More preferably, it is 0.05-25 micrometers, More preferably, it is 0.1-10 micrometers.

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, smectite, and organic particles such as acrylic beads. Can be mentioned.
Among these fine particles, one or more selected from silica particles, metal oxide particles, and smectites 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.
In addition, the silica particles used in one embodiment of the present invention include organic modified silica surface-modified with an organic compound having a reactive functional group, inorganic modified silica surface-treated with an inorganic compound such as sodium aluminate or sodium hydroxide In addition, organic-inorganic modified silica surface-treated with these organic compounds and inorganic compounds, organic-inorganic modified silica surface-treated with an organic-inorganic hybrid material such as a silane coupling agent, and the like may be used.
In addition, the mixture which consists of 2 or more types may be sufficient as these silica particles.

The mass concentration of silica in the silica particles is preferably 70 to 100% by mass, more preferably 85 to 100% by mass, and still more preferably 90 to 100% by mass with respect to 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 air release property and blister resistance of the pressure-sensitive adhesive sheet are improved, and the surface (α) of the resin layer has a recess and a flat surface. From the viewpoint of facilitating 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 diameter of the silica particles is a value obtained by measuring the particle size distribution by a Coulter counter method using a multisizer three machine or the like.

  Examples of the metal oxide particles include particles made of 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. The sol particle | grains which consist of these metal oxides are also included.

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

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%. It is 9 mass%, More preferably, it is 9-60 mass%.
The mass retention rate can be regarded as indicating the content (% by mass) of fine particles contained in the resin layer.
If the said mass retention is 3 mass% or more, it can become an adhesive sheet excellent in air bleeding property and blister resistance. Moreover, at the time of manufacture of the pressure-sensitive adhesive sheet of the present invention, recesses and flat surfaces are easily formed on the surface (α) of the resin layer. On the other hand, if the mass retention is 90% by mass or less, the resin layer has high film strength, and can be a pressure-sensitive adhesive sheet having excellent water resistance and chemical resistance.

[Method for producing adhesive sheet]
Next, the manufacturing method of the adhesive sheet of this invention is demonstrated.
Although there is no restriction | limiting in particular as a manufacturing method of the adhesive sheet of this invention, From a viewpoint of productivity and the viewpoint of making it easy to form a recessed part and a flat surface on the surface ((alpha)) of a resin layer, at least following process (1). And (2) is preferred.
Step (1): a coating film (x ′) comprising a composition (x) containing a resin and having a fine particle content of less than 15% by mass, and a coating film comprising a composition (y) comprising 15% by mass or more of fine particles Step of forming (y ′) Step (2): Step of simultaneously drying the coating film (x ′) and the coating film (y ′) formed in step (1)

<Step (1)>
Step (1) includes a coating film (x ′) comprising a composition (x) containing a resin and having a fine particle content of less than 15% by mass, and a coating comprising a composition (y) comprising 15% by mass or more of fine particles. This is a step of forming a film (y ′).
The composition (x) is a material for forming the resin portion (X), and preferably contains a crosslinking agent together with the above-mentioned resin, and may further contain a tackifier and the above-mentioned general-purpose additives.
The composition (y) is a material for forming the particle part (Y), but may further contain a resin, a crosslinking agent, a tackifier, and the above-mentioned general-purpose additives. The composition (y) containing components other than fine particles such as these resins is a forming material for the particle portion (Y) and a forming material for the resin portion (X).

(Composition (x))
Examples of the resin contained in the composition (x) include a resin constituting the above-described resin part (X), and an adhesive resin having a functional group is preferable, and an acrylic resin (A) having the above-described functional group. Is more preferable, and the above-mentioned acrylic copolymer (A1) is more preferable.

  The content of the resin in the composition (x) is usually 30% by mass or more, preferably 40% by mass or more, based on the total amount of the composition (x) (100% by mass (excluding the dilution solvent)), More preferably, it is 50 mass% or more, More preferably, it is 55 mass% or more, More preferably, it is 60 mass% or more, More preferably, it is 70 mass% or more, Preferably it is 100 mass% or less, More preferably, it is 99.9. It is 95 mass% or less, More preferably, it is 95 mass% or less.

Moreover, as a crosslinking agent contained in a composition (x), although the crosslinking agent contained in the above-mentioned resin part (X) is mentioned, a composition (x) is a metal chelate type crosslinking agent and an epoxy type crosslinking | crosslinking. It is preferable that 1 or more types chosen from an agent are included, and it is more preferable that a metal chelate type crosslinking agent is included.
Furthermore, as one aspect of the present invention, from the viewpoint of improving the shape maintaining property of the plurality of recesses present on the surface (α) of the resin layer, the composition (x) is composed of a metal chelate crosslinking agent and an epoxy crosslinking agent. It is preferable that both are included.
When the composition (x) contains both a metal chelate crosslinking agent and an epoxy crosslinking agent, the content ratio of the metal chelate crosslinking agent and the epoxy crosslinking agent in the composition (x) [metal chelate crosslinking agent / epoxy The cross-linking agent] is preferably 10/90 to 99.5 / 0.5, more preferably 50/50 to 99.0 / 1.0, and still more preferably 65/35 to 98.5 in terms of mass ratio. /1.5, more preferably 75/25 to 98.0 / 2.0.

  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 100 parts by mass with respect to 100 parts by mass of the resin contained in the composition (x). 3 to 7.0 parts by mass.

The composition (x) is preferably an acrylic pressure-sensitive adhesive containing the above-mentioned acrylic resin (A) having a functional group and a crosslinking agent (B), and the above-mentioned acrylic copolymer (A1) and cross-linking. The acrylic pressure-sensitive adhesive containing the agent (B) is more preferable. Moreover, the said acrylic adhesive may contain a tackifier and a general purpose additive further.
The details of the acrylic pressure-sensitive adhesive are as described above.

The composition (x) may contain the fine particles described above.
However, the content of the fine particles in the composition (x) is less than 15% by mass and is smaller than the content of the resin contained in the composition (x).
The content of the fine particles in the specific composition (x) is less than 15% by mass with respect to the total amount of the composition (x) (100% by mass (excluding the diluting solvent)), preferably 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.

(Composition (y))
The composition (y) is a material for forming the particle portion (Y), and contains at least 15% by mass of the above-mentioned fine particles. From the viewpoint of fine particle dispersibility, the composition (y) preferably contains a resin together with the fine particles. It is more preferable to contain a crosslinking agent together with the resin. The composition (y) may further contain a tackifier and a general-purpose additive.
In addition, components (resin, crosslinking agent, tackifier, and general-purpose additive) other than the fine particles contained in the composition (y) serve as a forming material for the resin portion (X).

Examples of the fine particles contained in the composition (y) include those described above. From the viewpoint of forming a void portion (Z) in the resin layer and improving the blister resistance, silica particles are used. One or more selected from metal oxide particles and smectite are preferred.
The content of the fine particles in the composition (y) is such that the irregular recesses and flat surfaces formed by the self-formation of the resin layer are easily formed on the surface (α) of the resin layer. Although it is 15 mass% or more with respect to the whole quantity (100 mass% (however, except a dilution solvent)) of (y), Preferably it is 20-100 mass%, More preferably, it is 25-90 mass%, More preferably, 30-85 mass%, More preferably, it is 35-80 mass%.

As resin contained in a composition (y), the same thing as resin contained in the above-mentioned composition (x) is mentioned, It is preferable that the same resin as composition (x) is included. In addition, you may use these resin individually or in combination of 2 or more types.
Further, as a more specific resin contained in the composition (y), a resin having a functional group is preferable, an acrylic resin (A) having the above-described functional group is more preferable, and the above-mentioned acrylic copolymer (A1) is more preferable.

  The content of the resin in the composition (y) is usually 0 to 85% by mass, preferably 1 to 80% by mass with respect to the total amount of the composition (y) (100% by mass (excluding the dilution solvent)). %, More preferably, it is 5-75 mass%, More preferably, it is 10-70 mass%, More preferably, it is 20-65 mass%.

Moreover, as a crosslinking agent contained in a composition (y), the same thing as the crosslinking agent contained in the above-mentioned resin part (X) is mentioned. Among these, it is preferable that the composition (y) contains 1 or more types chosen from a metal chelate type crosslinking agent and an epoxy type crosslinking agent, and it is more preferable that a metal chelate type crosslinking agent is included. Furthermore, as one aspect of the present invention, the composition (y) preferably contains both a metal chelate crosslinking agent and an epoxy crosslinking agent.
In addition, when composition (y) contains both a metal chelate type crosslinking agent and an epoxy type crosslinking agent, suitable content ratio (mass ratio) of the metal chelate type crosslinking agent and epoxy type crosslinking agent in composition (y) Is the same as that of the above-mentioned composition (x).

  The content of the crosslinking agent in the composition (y) is preferably 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the resin contained in the composition (y). Part, more preferably 0.3 to 7.0 parts by weight.

(Formation method of coating film (x ′), (y ′))
In addition, when forming a coating film, in order to make it easy to form a coating film, it is preferable to mix | blend a solvent with composition (x) and (y), and make it the form of the solution of a composition.
Examples of such a solvent include water and organic solvents.
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, and cyclohexane. . These solvents may be used alone or in combination of two or more.

The order of laminating the coating films (x ′) and (y ′) formed in this step is not particularly limited, but the coating film (x ′) should be laminated on the coating film (y ′). Is preferred.
As a method for forming the coating films (x ′) and (y ′), after the coating film (y ′) is formed, the coating film (x ′) may be sequentially formed on the coating film (y ′). Further, from the viewpoint of productivity, a method of simultaneously forming the coating film (y ′) and the coating film (x ′) with a multilayer coater may be used.
Examples of the coater used for sequential formation include spin coater, spray coater, bar coater, knife coater, roll coater, knife roll coater, blade coater, gravure coater, curtain coater, and die coater.
Examples of the coater used for simultaneous application with a multilayer coater include a curtain coater and a die coater. Among these, a die coater is preferable from the viewpoint of operability.

In this step (1), after the formation of at least one of the coating film (x ′) and the coating film (y ′), before proceeding to the step (2), the pre-treatment is such that the curing reaction of the coating film does not proceed. You may give a drying process.
In this step (1), the drying temperature at the time of performing the pre-drying treatment is usually appropriately set within a temperature range in which the formed coating film does not proceed, but preferably in step (2). Is lower than the drying temperature. The specific drying temperature indicated by the definition of “below the drying temperature in step (2)” is preferably 10 to 45 ° C., more preferably 10 to 34 ° C., and further preferably 15 to 30 ° C.

<Step (2)>
Step (2) is a step of simultaneously drying the coating film (x ′) and the coating film (y ′) formed in step (1).
In this step, by simultaneously drying the formed coating film (x ′) and coating film (y ′), a resin layer containing the resin part (X) and the particle part (Y) is formed, and A plurality of recesses and a flat surface are formed on the surface (α) of the resin layer.

The drying temperature in this step is preferably 35 to 200 ° C., more preferably 60 to 180 ° C., and still more preferably 70 to 160 ° C., from the viewpoint of facilitating formation of recesses and flat surfaces on the surface (α) of the resin layer. More preferably, it is 80-140 degreeC.
When the drying temperature is 35 ° C. or higher, a pressure-sensitive adhesive sheet with good air release properties can be obtained. On the other hand, if the said drying temperature is 200 degrees C or less, the malfunction that the base material and peeling material which an adhesive sheet has shrink | contracts can be suppressed.
Note that the lower the drying temperature, the greater the difference in height of the recesses formed, but the number of recesses formed tends to decrease.

In addition, the void portion (Z) is easily formed around the particle portion (Y) of the resin layer formed by this step.
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 (y).

  Moreover, like the adhesive sheet 1a of Fig.1 (a), the layer (X (beta)) mainly containing the resin part (X), the layer (Y1) containing 15 mass% or more of particle parts (Y), and mainly resin In the case of producing a pressure-sensitive adhesive sheet having a resin layer formed by forming a multilayer structure in which layers (Xα) including a part (X) are laminated in this order, the production methods of the first and second embodiments shown below Is preferred.

  In the description of the production methods of the first and second aspects below, “composition (xβ)” and “composition (xα)” are the same as the above-described composition (x) unless otherwise specified. Details of each component (resin, crosslinking agent, tackifier, general-purpose additive, diluent solvent, etc.) contained in the composition (xβ) or (xα) (specific examples of each component, suitable components) , Component content, solid content concentration, etc.) are also the same as in the composition (x) described above. The “composition (y)” is also as described above.

[Production Method of First Embodiment]
The manufacturing method of the first aspect includes at least the following steps (1A) and (2A).
Step (1A): a coating film (xβ ′) composed of a composition (xβ) containing a resin and having a fine particle content of less than 15% by mass on the substrate or the release material, and a composition containing 15% by mass or more of the fine particles. A coating film (y ′) made of the product (y) and a coating film (xα ′) made of a composition (xα) containing a resin and containing fine particles of less than 15% by mass are laminated in this order. Step (2A): A step of simultaneously drying the coating film (xβ ′), the coating film (y ′), and the coating film (xα ′) formed in the step (1A).

Also in the step (1A), it is preferable that the composition (xβ), the composition (y), 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 (xβ ′), the coating film (y ′), and the coating film (xα ′), the coating film (xβ ′) is formed on the substrate or the release material, and then the coating film (xβ A method of sequentially forming using a coater as described above may be used, such as forming a coating film (y ') on the coating film (y) and forming a coating film (xα') on the coating film (y '). The film (xβ ′), the coating film (y ′), and the coating film (xα ′) may be formed by simultaneous application using the multilayer coater.

In this step (1A), after forming one or more coating films (xβ ′), coating film (y ′), and coating film (xα ′), before moving to step (2A), You may perform the predrying process of the grade which the hardening reaction of the said coating film does not advance.
For example, the pre-drying treatment may be performed each time after the coating film (xβ ′), the coating film (y ′), and the coating film (xα ′) are formed. ) And the coating film (y ′), the coating film (xα ′) may be formed after the above pre-drying treatment.
In this step (1A), the drying temperature at the time of performing the pre-drying treatment is usually appropriately set in a temperature range in which the formed coating film does not cure, but preferably in step (2A). Is lower than the drying temperature. The specific drying temperature indicated by the prescription “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.

  The step (2A) is a step of simultaneously drying the coating film (xβ ′), the coating film (y ′), and the coating film (xα ′) formed in the step (1A). The range is the same as in step (2) above. By this step, a resin layer including the resin portion (X) and the particle portion (Y) is formed.

[Production Method of Second Aspect]
As a manufacturing method of a 2nd aspect, it has the following process (1B) and (2B) at least.
Step (1B): a coating film comprising a composition (y) containing 15% by mass or more of the fine particles on a layer (Xβ) mainly containing a resin portion (X) provided on a substrate or a release material ( Step (2B): A coating film (y) formed by laminating and forming a coating film (xα ′) made of a composition (xα) containing a resin as a main component in this order (y ′) ') And the step of simultaneously drying the coating film (xα')

In the step (1B), the “layer (Xβ) mainly including the resin portion (X)” is formed by drying the coating film (xβ ′) made of the composition (xβ) including the resin as the main component. be able to.
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 as a main component is formed on a substrate or a release material, and the coating film (xβ ′) is dried. Can be formed.
There is no restriction | limiting in particular as drying temperature at this time, Preferably it is 35-200 degreeC, More preferably, it is 60-180 degreeC, More preferably, it is 70-160 degreeC, More preferably, it is 80-140 degreeC.

In this embodiment, the coating film (y ′) 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 first aspect described above.
Also in the step (1B), it is preferable that the composition (y) 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 (y ′) and the coating film (xα ′), after forming the coating film (y ′) on the layer (Xβ), the coating film (xα ′) is formed on the coating film (y ′). ) May be sequentially formed using the above-described coater, or may be a method in which the coating film (y ′) and the coating film (xα ′) are simultaneously applied and formed using the above-described multilayer coater. Good.

In this step (1B), after the formation of the coating film (y ′), or after the formation of the coating film (y ′) and the coating film (xα ′), before moving to the step (2B), the coating film You may perform the predrying process of the grade which does not advance hardening reaction.
In this step (1B), the drying temperature at the time of performing the pre-drying treatment is usually appropriately set within a temperature range in which the formed coating film does not cure, but preferably in step (2B). Is lower than the drying temperature. The specific drying temperature indicated by the definition of “below the drying temperature in step (2B)” is preferably 10 to 45 ° C., more preferably 10 to 34 ° C., and further preferably 15 to 30 ° C.

  The step (2B) is a step of simultaneously drying the coating film (y ′) and the coating film (xα ′) formed in the step (1B). The preferred range of the drying temperature in this step is the above-described step (2). ). By this step, a resin layer including the resin portion (X) and the particle portion (Y) is formed.

  The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples. In addition, the physical-property value in the following manufacture examples and Examples is a value measured by the following method.

<Mass average molecular weight (Mw)>
Using a gel permeation chromatograph device (product name “HLC-8020” manufactured by Tosoh Corporation), the value measured under the following conditions and 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” (both 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 three machine (manufactured by Beckman Coulter, Inc.).

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

Production Examples x-1 to x-4
(Preparation of resin composition solutions (xβ-1) to (xβ-2) and (xα-1) to (xα-2))
The cross-linking agent and tackifier shown in Table 1 were added to the acrylic resin solution, which is the type and solid content of the adhesive resin shown in Table 1. And it dilutes using the dilution solvent of Table 1, and the solution (x (beta) -1)-(x (beta) -2) and (x (alpha) -1)-(x (alpha) -1) of the resin composition which has the solid content density | concentration of Table 1. -2) were prepared respectively.

In addition, the detail of each component of Table 1 used for preparation of the solution (x (beta) -1)-(x (beta) -2) and (x (alpha) -1)-(x (alpha) -2) of a resin composition is as follows. .
<Acrylic resin solution>
Solution (i): Acrylic resin (xi) (acrylic copolymer having a structural unit derived from a raw material monomer consisting of BA / AA = 90/10 (mass%), Mw: 630,000) A mixed solution of toluene and ethyl acetate having a solid content concentration of 34.0% by mass.
Solution (ii): Acrylic resin (x-ii) (acrylic copolymer having a structural unit derived from a raw material monomer consisting 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 (iii): acrylic resin (x-iii) (2EHA / VAc / AA = acrylic copolymer having a structural unit derived from a raw material monomer consisting of 75/23/2 (mass%), Mw: 66 A mixed solution of toluene and isopropyl alcohol (IPA) having a solid content concentration of 37.0% by mass.
Solution (iv): acrylic resin (x-iv) (acrylic copolymer having structural units derived from raw material monomers consisting of BA / AA / HEA = 94/3/3 (mass%), Mw: 100 Solution of ethyl acetate having a solid content concentration of 37.0% by mass.
In addition, the abbreviation of the raw material monomer which said acrylic copolymer comprises is as follows.
BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate AA: acrylic acid VAc: vinyl acetate HEA: 2-hydroxyethyl acrylate

<Crosslinking agent>
Al-based crosslinking agent: Product name “M-5A”, manufactured by Soken Chemical Co., Ltd., aluminum chelate-based crosslinking agent, solid content concentration = 4.95% by mass.
Epoxy-based crosslinking agent: A solution of an epoxy-based 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 mass%.

<Tackifier>
Rosin ester TF: Rosin ester tackifier, Mw: less than 10,000, softening point: 85 ° C.
-Styrenic TF: Styrenic tackifier comprising a copolymer of a styrene monomer and an aliphatic monomer, Mw: less than 10,000, softening point: 95 ° C.

<Diluted solvent>
-Mixed solvent (1): Mixed solvent formed by mixing with toluene / isopropyl alcohol (IPA) = 65/35 (mass ratio).
-Mixed solvent (2): Mixed solvent formed by mixing with ethyl acetate / IPA = 86/14 (mass ratio).

Production Example f-1
(Preparation of fine particle dispersion (f-1))
Solution (i) of acrylic resin containing the acrylic resin (xi) described above (acrylic copolymer having structural units derived from butyl acrylate (BA) and acrylic acid (AA), BA / AA = 90 / 10 (mass%), Mw: 630,000) containing 100 parts by mass (solid content: 34.0 parts by mass) of a mixed solution of toluene and ethyl acetate having a solid content concentration of 34.0% by mass, As fine particles, 51.0 parts by mass (solid content: 51.0 parts by mass) of silica particles (product name “Nip seal E-200A”, manufactured by Tosoh Silica Co., Ltd., volume average secondary particle size: 3 μm) and toluene are added. Then, the fine particles were dispersed to prepare a fine particle dispersion (f-1) containing an acrylic resin and silica particles and having a solid content concentration of 27% by mass.

Production Example f-2
(Preparation of fine particle dispersion (f-2))
In place of the solution (i), the solution (ii) containing the above acrylic resin (x-ii) (an acrylic copolymer having structural units derived from butyl acrylate (BA) and acrylic acid (AA), BA / AA = 90/10 (mass%), Mw: 470,000) solid content concentration 37.0 mass% toluene and ethyl acetate mixed solution) 100 mass parts (solid content: 37.0 mass parts) In contrast, 55.5 parts by mass (solid content: 55.5 parts by mass) of silica particles (product name “Nip Seal E-200A”, manufactured by Tosoh Silica Co., Ltd., volume average secondary particle size: 3 μm) as fine particles And toluene were added to disperse the fine particles to prepare a fine particle dispersion (f-2) containing an acrylic resin and silica particles and having a solid content concentration of 30% by mass.

Production Examples y-1 to y-2
(Preparation of coating solutions (y-1) to (y-2) for forming a coating film (y ′))
A coating liquid for forming a coating film (y ′) having a solid content concentration shown in Table 2 by adding a fine particle dispersion of the type and blending amount shown in Table 2, an acrylic resin solution, a crosslinking agent, and a diluent solvent. (Y-1) to (y-2) were respectively prepared.

In addition, the detail of each component of Table 2 used for preparation of coating liquid (y-1)-(y-2) for coating-film (y ') formation is as follows.
<Fine particle dispersion>
-Dispersion (f-1): A fine particle dispersion (f-1) prepared in Production Example f-1 and containing an acrylic resin (xi) and silica particles and having a solid content concentration of 27% by mass.
-Dispersion liquid (f-2): Fine particle dispersion liquid (f-2) prepared in Production Example f-2 and containing an acrylic resin (x-ii) and silica particles at a solid content concentration of 30% by mass.
<Acrylic resin solution>
Solution (i): Acrylic resin (xi) (acrylic copolymer having a structural unit derived from a raw material monomer consisting of BA / AA = 90/10 (mass%), Mw: 630,000) A mixed solution of toluene and ethyl acetate having a solid content concentration of 34.0% by mass.
Solution (ii): Acrylic resin (x-ii) (acrylic copolymer having a structural unit derived from a raw material monomer consisting 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 crosslinking agent: Product name “M-5A”, manufactured by Soken Chemical Co., Ltd., aluminum chelate-based crosslinking agent, solid content concentration = 4.95% by mass.
Epoxy-based crosslinking agent: A solution of an epoxy-based 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 mass%.
<Diluted solvent>
IPA / CHN: Mixed solvent composed of isopropyl alcohol (IPA) and cyclohexanone (CHN) (IPA / CHN = 95/5 (mass ratio)).

Examples 1-2
(1) Formation of coating film Peeling of a peeling film (product of Lintec Co., Ltd., product name “SP-PET381031”, thickness 38 μm, provided with a silicone release agent layer on one side of a PET film) as a first release material On the agent layer, as shown in Table 3, the resin composition solution (xβ-1) prepared in Production Example x-1 and the coating solution (y ′) forming coating solution prepared in Production Example y-1 A multilayer die coater (y-1) and a solution (xβ-1) of the resin composition prepared in Production Example x-1 were formed in this order from the release agent layer (for coating film (xα ′) formation). (Width: 250 mm) was simultaneously applied, and a coating film (xβ ′), a coating film (y ′), and a coating film (xα ′) were simultaneously formed in this order.
In addition, the coating speed of each solution (coating liquid) 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 treatment Then, the three-layer coating film (xβ ′), the coating film (y ′), and the coating film (xα ′) are simultaneously dried at a drying temperature of 100 ° C. for 2 minutes to obtain a resin portion (X ) And a particle portion (Y), and a resin layer having a thickness shown in Table 3 was formed.
In any of Examples 1 and 2, a plurality of concave portions and a flat surface were also visually confirmed on the surface (α) of the formed resin layer.

(3) Production of adhesive sheet without substrate and adhesive sheet with substrate On the surface (α) of the formed resin layer, a release film as a second release material (product name “SP-PET386060” manufactured by Lintec Corporation) The laminate was laminated so as to be bonded to the surface of the release agent layer, and an adhesive sheet without a substrate was produced.
Further, after the above-prepared adhesive sheet without base material was allowed to stand in a 23 ° C. environment for one week, the first release material was removed, and the surface (β) of the exposed resin layer and the base material were removed. Were laminated so as to be bonded to a polyethylene terephthalate (PET) film (product name “Lumirror T60 # 50”, thickness 50 μm, manufactured by Toray Industries, Inc.) to prepare a pressure-sensitive adhesive sheet with a substrate.

Examples 3-4
(1) Formation of coating film Table 3 on the surface of an aluminum vapor deposition layer of a polyethylene terephthalate (PET) film (Lintec Co., Ltd., “FNS Poppy N50”, thickness 50 μm) provided with an aluminum vapor deposition layer on one side As described above, the resin composition solution (xβ-2) prepared in Production Example x-2, the coating liquid (y ′)-forming coating solution (y-2) prepared in Production Example y-2, and Production Example The resin composition solution (xα-1) or (xα-2) prepared in x-3 to x-4 is applied simultaneously in this order from the aluminum vapor deposition layer using a multilayer die coater (width: 250 mm). The coating film (xβ ′), the coating film (y ′), and the coating film (xα ′) were simultaneously formed in this order.
In addition, the coating speed of each solution (coating liquid) 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 treatment Then, the three-layer coating film (xβ ′), the coating film (y ′), and the coating film (xα ′) are simultaneously dried at a drying temperature of 100 ° C. for 2 minutes to obtain a resin portion (X ) And a particle portion (Y), and a resin layer having a thickness shown in Table 3 was formed.
In any of Examples 3 to 4, a plurality of concave portions and a flat surface were also visually confirmed on the surface (α) of the formed resin layer.

(3) Production of pressure-sensitive adhesive sheet with a base material A pressure-sensitive adhesive sheet with a base material was obtained by laminating so as to be bonded to the surface of the release agent layer of a release film (manufactured by Lintec Corporation, product name “SP-PET381031”).

Comparative Examples 1-4
(1) Production of Embossed Release Paper A 25 μm-thick resin film made of low-density polyethylene resin (manufactured by Sumitomo Chemical Co., Ltd., product name “Sumikasen (L705)”, melting point 106 °) was formed on one surface of high-quality paper. Then, the surface of the metal engraving plate is brought into close contact with the surface of the resin film, and in that state, the surface is inserted between two rotating silicon rubber rollers heated to 115 ° C., and the surface of the resin layer is embossed. It was.
On the surface of the resin film after embossing, a silicone release agent (product name "SP-PET1031 same release agent" manufactured by Lintec Co., Ltd.) was applied and then dried at 100 ° C for 1 minute, and the thickness was 110 µm. Embossed release paper was prepared.
In addition, the uneven | corrugated formation surface of a metal engraving board is what was processed so that the recessed part and flat surface of each shape might be formed in the surface ((alpha)) of the resin layer of the adhesive sheet produced in Comparative Examples 1-4. used.
(2) Preparation of pressure-sensitive adhesive sheet with substrate The resin composition solution (xβ-1) prepared in Production Example x-1 described in Table 1 on the release agent layer of the embossed release paper prepared in (1) above Was applied using an applicator and then dried at 100 ° C. for 1 minute to form a resin layer so that the coating speed and the coating amount of each coating film described in Example 1 in Table 3 were obtained.
And it laminated so that a PET film (the product name "Lumirror T60 # 50", thickness 50 micrometers) by Toray Industries, Inc. may be bonded) on the surface ((alpha)) of the resin layer, and produced the adhesive sheet with a base material.

  Using the adhesive sheet without a base material or the adhesive sheet with a base material prepared in Examples and Comparative Examples, the characteristics of the resin layer and the adhesive sheet included in the adhesive sheet were measured or observed by the following method. These results are shown in Tables 4 and 5.

(1) Preparation of measurement sample As shown in FIG. 4 (a), in order to eliminate the influence of waviness and the like of the pressure-sensitive adhesive sheet, alkali-free glass (product name “Eagle XG”, which is an adherend 101 having a smooth surface, Corning Co., Ltd.) and the base material of the pressure-sensitive adhesive sheet prepared in Examples and Comparative Examples were pasted through a double-sided tape.
And the peeling material laminated | stacked on the surface ((alpha)) of the resin layer of the said adhesive sheet was removed, and what measured the surface ((alpha)) of the resin layer was used as the measurement sample.

(2) Acquisition of image of region (D) and region (Q) on surface (α) The surface (α) of the resin layer exposed from the measurement sample is obtained using a digital microscope (50 times magnification). An arbitrarily selected range on the surface (α) was photographed from the direction A in FIG. 4A, and a connected image obtained by connecting a plurality of adjacent images by the image connecting function of the digital microscope was obtained. .
More specifically, at the time of the imaging, more specifically, the focal point is moved in order from above the portion that is visually determined to be a flat surface from the direction A in FIG. Taken as.
Then, in the acquired connected image, an area (D) surrounded by a rectangle of 8 mm in length and 10 mm in width is arbitrarily selected as one area, and this is set as an “area (D) image”.
Further, in the acquired connected image, an area (Q) surrounded by a square having a side of 1 mm is arbitrarily selected as one area, and this is defined as an “area (Q) image”.

Note that the imaging conditions of the digital microscope in (2) above are as follows.
(measuring equipment)
KEYENCE CO., LTD., Product name “Digital Microscope VHX-5000”, High Resolution Zoom Lens VHX-ZST 100x (Measurement Conditions)
-Epi-illumination: ON
-Stage transmitted illumination: OFF
・ Lighting change: Coaxial incident light ・ Edge enhancement: OFF

(3) Calculation of various measurement values concerning flat surfaces and recesses existing in the region (D) Based on the “image of the region (D)” obtained in the above (2), an automatic area is obtained using the same digital microscope as described above. Measurement was performed, and various measured values (area (S), circumference (L)) of each flat surface and each recess existing in the region (D) were measured.
In addition, the automatic area measurement is performed by binarizing the flat portion and the concave portion existing in the region (D) by a digital microscope and, if necessary, visual image processing, and then the numerical value of the obtained binarized image. Measurement was performed and various measured values of each flat surface and each concave portion were measured.
As a specific operation for binarization of the above image, after performing automatic color separation based on the difference in luminance of the digital image between the flat surface and the concave portion, the area is confirmed while checking the original digital image by the area confirmation function. The validity of the surface was judged and binarization was performed by image processing by adding corrections. In this image processing, depending on the type and color of the base material, there may be a difference in brightness even on a flat surface. Made corrections.
In addition, when it is impossible to determine whether the surface is flat or not by visual inspection of the image, a squeegee is applied so as not to apply a load to the translucent adherend having a smooth surface on the surface (α) of the resin layer as much as possible. Then, the interface between the smooth surface 100a of the translucent adherend 100 and the surface (α) 12a of the resin layer 12 is photographed from the W direction in FIG. Of these, the smooth surface 100a and the pasted portion were determined to be a flat surface.

Data of various measured values (area, perimeter length) of each flat surface and each concave portion obtained were arranged using graph software (product name “Excel” manufactured by Microsoft Japan Co., Ltd.).
Then, from the data, “flat surface (R)” data was extracted by excluding flat surfaces with a cumulative relative frequency of 30% or less obtained by adding the relative frequencies from the smaller area of each flat surface.
Then, the ratio (L / S) between the area (S) [μm ² ] and the perimeter (L) [μm] was calculated for each extracted flat surface (R). For a plurality of flat surfaces (R), the average value of the ratio (L / S), the standard deviation with respect to the average value of the ratio (L / S), and the skewness Sk with respect to the normal distribution curve of the ratio (L / S) and frequency The value, the maximum value of the ratio (L / S), the median value of the ratio (L / S), and the difference between the maximum value and the median value of the ratio (L / S) were calculated. Table 4 shows the calculation results.

The evaluation criteria for the items described in Table 5 are shown below.
<Whether or not the concave portion and the flat surface can be visually confirmed>
Evaluation item (a): The surface (α) of the exposed resin layer of the measurement sample prepared in (1) above is visually observed, and the presence of concave portions and flat surfaces on the surface (α) is visually confirmed. Whether it was possible was evaluated according to the following criteria.
A: The presence of a concave portion and a flat surface on the surface (α) can be visually confirmed.
F: Presence of a concave portion and a flat surface on the surface (α) cannot be confirmed by visual observation.

<Evaluation on shapes of recesses and flat surfaces>
From the “image of region (D)” or “image of region (Q)” acquired in (2) above, observations regarding the following evaluation items (b1) to (b4) and (c1) to (c4) are performed, Evaluation based on each standard was performed.

(Evaluation item regarding shape and position of flat surface existing in region (D))
Evaluation item (b1): From the acquired “image of region (D)”, whether or not an irregular flat surface exists in the region (D) was evaluated according to the following criteria.
A: There are a plurality of irregularly shaped flat surfaces.
B: There is only one amorphous flat surface.
C: There is no amorphous flat surface.

Evaluation item (b2): Whether or not there is a flat surface having a size capable of selecting a region surrounded by a circle having a diameter of 100 μm or more in the region (D) from the acquired “image of region (D)”. Was evaluated according to the following criteria.
A +: A flat surface having an area capable of selecting a region surrounded by a circle having a diameter of 200 μm exists in the region (D).
A: A flat surface having an area in which a region surrounded by a circle having a diameter of 150 μm can be selected exists in the region (D).
B: In the region (D), there is a flat surface having a width capable of selecting a region surrounded by a circle having a diameter of 100 μm.
C: In the region (D), there is no flat surface having an area capable of selecting a region surrounded by a circle having a diameter of 100 μm.

Evaluation item (b3): From the acquired “image of the region (D)”, whether or not the position where the plurality of flat surfaces of the region (D) exists has periodicity was evaluated according to the following criteria.
A: A position where a plurality of flat surfaces exist does not have periodicity.
F: A position where a plurality of flat surfaces exist has periodicity, or a plurality of flat surfaces do not exist in the region (D).

Evaluation item (b4): From the acquired “image of the region (D)”, whether or not the shape of the flat surface existing in the region (D) has a shape that becomes a constant repeating unit is as follows: It was evaluated according to the criteria.
A: The shape of the flat surface does not have a shape that becomes a constant repeating unit.
F: The shape of the flat surface is a constant repeating unit.

(Evaluation items regarding the shape and position of the recesses present in the region (D))
Evaluation item (c1): From the acquired “image of the region (D)”, it was evaluated according to the following criteria whether or not there was an irregular recess in the region (D).
A: There are a plurality of irregular recesses.
B: There is only one irregular recess.
C: There are no irregular recesses.

Evaluation item (c2): From the acquired “image of region (D)”, whether or not there are a plurality of recesses in the region (D) and the positions where the plurality of recesses exist has periodicity is as follows: It was evaluated according to the criteria. The results are shown in Table 5.
A: A position where a plurality of recesses are present has no periodicity.
F: The position where a plurality of recesses exist has periodicity, or there are no plurality of recesses in the region (D).

Evaluation item (c3): From the acquired “image of the region (D)”, whether or not the shape of the concave portion existing in the region (D) has a shape that becomes a constant repeating unit is determined as follows. Evaluation was made according to the criteria.
A: The shape of the concave portion does not have a shape that becomes a constant repeating unit.
F: The shape of the concave portion is a certain repeating unit.

(Evaluation item regarding presence / absence of irregular recess in region (Q))
Evaluation item (c4): From the acquired “image of region (Q)”, it was evaluated according to the following criteria whether or not there was an irregular recess in the region (Q).
A: There are a plurality of irregular recesses in the region (Q).
B: There is only one irregular recess in the region (Q).
C: There are no irregular recesses in the region (Q).

<Area ratio of flat surface and recess>
All the flat surfaces existing in the region (D) before excluding “a flat surface having a cumulative relative frequency of 30% or less obtained by adding a relative frequency from the smaller area of each flat surface” acquired in (3) above, and Based on the data of the area of the recess, “area ratio (%) occupied by the flat surface” and “area ratio (%) occupied by the recess” with respect to the total area of the region (D) were calculated.
Moreover, the physical property value regarding the following evaluation items (d1) to (d2) and (e1) to (e2) was also calculated or evaluated using the data.

<Evaluation regarding the area of the flat surface and the concave portion present in the region (D)>
Evaluation item (d1): Whether or not there is a flat surface with an area of 0.2 mm ² or more in the region (D) was evaluated according to the following criteria.
A +: There are a plurality of flat surfaces having an area of 0.4 mm ² or more.
A: area exists one is 0.4 mm ² or more flat surfaces, apart from the area flat surface of less than 0.2 mm ² or more 0.4 mm ² there are a plurality.
B +: There are a plurality of flat surfaces having an area of 0.2 mm ² or more and less than 0.4 mm ² .
B: One flat surface having an area of 0.2 mm ² or more and less than 0.4 mm ² exists.
C: The maximum value of the area of the flat surface existing in the region (D) is less than 0.2 mm ² .

Evaluation item (d2): The ratio of the area occupied by the amorphous flat surface existing in the region (D) to the total area of the flat surface existing in the region (D) was calculated and evaluated according to the following criteria.
A +: The area ratio occupied by the irregular flat surface is 100%.
A: The area ratio occupied by the irregular flat surface is 90% or more and less than 100%.
B: The area ratio occupied by the irregular flat surface is 80% or more and less than 90%.
C: The area ratio occupied by the irregular flat surface is less than 80%.

Evaluation item (e1): The area ratio of the concave portion having the maximum area in the region (D) to the total area of the concave portion existing in the region (D) was calculated from the following formula.
[Area ratio (%) occupied by recess having maximum area] = [area of recess having maximum area] / [total area of recess] × 100

Evaluation item (e2): The ratio of the area occupied by the irregular recesses present in the region (D) to the total area of the recesses present in the region (D) was calculated and evaluated according to the following criteria.
A +: The area ratio occupied by the irregular recess is 100%.
A: The area ratio occupied by the irregular recess is 90% or more and less than 100%.
B: The area ratio occupied by the irregular recess is 80% or more and less than 90%.
C: The area ratio occupied by the irregular recess is less than 80%.

<Mass retention rate of resin layer of adhesive sheet>
After obtaining the resin layer alone from the adhesive sheet, the mass of the resin layer before heating was measured. The resin layer was placed in a muffle furnace (product name “KDF-P90” manufactured by Denken Co., Ltd.) and heated at 800 ° C. for 30 minutes. And the mass of the resin layer after a heating was measured and the mass retention of the resin layer was computed by the following formula.
Mass retention of resin layer (%) = [mass of resin layer after heating] / [mass of resin layer before heating] × 100

<Air escape characteristics>
Adhesive sheet with base material of 50mm in length x 50mm in width is stuck on the melamine coating plate which is an adherend so that air accumulation occurs, and it is weakly crimped when the area around the air accumulation is strongly crimped with a squeegee. Two types of cases were prepared. And the presence or absence of the air pocket after sticking trying to remove an air pocket using a squeegee was observed, and the air bleeding property of each adhesive sheet was evaluated according to the following criteria.
5: The air pocket disappears in both cases of weak pressure bonding and strong pressure bonding.
4: When pressure is weakly bonded, the air pocket disappears. In the case of strong pressure bonding, most of the air reservoir disappears, and the remaining air reservoir disappears if pressure is applied again.
3: When pressure is weakly bonded, the air pocket disappears. On the other hand, when pressure is strongly applied, there is a portion where a part of the air pool remains.
2: When the pressure is weakly bonded, most of the air pocket disappears, and the remaining air pool disappears if the pressure is pressed again. On the other hand, when pressure is strongly applied, an air pocket remains.
1: An air reservoir remains in both cases of weak pressure bonding and strong pressure bonding.

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

<Blister resistance>
Adhesive sheet with base material measuring 50 mm long × 50 mm wide is affixed to a polymethyl methacrylate plate (product name “Acrylite L001”, manufactured by Mitsubishi Rayon Co., Ltd.) 70 mm long × 150 mm wide × 2 mm thick. A test sample was prepared by strongly pressure-bonding.
This test sample was allowed to stand at 23 ° C. for 12 hours, then left in an 80 ° C. hot air dryer for 1.5 hours, and further left in a 90 ° C. hot air dryer for 1.5 hours, after heating was promoted. The blister generation state was visually observed, and the blister resistance of each pressure-sensitive adhesive sheet was evaluated according to the following criteria.
A: No blisters were confirmed.
B: A blister was partially confirmed.
C: Blister was confirmed on the entire surface.

<Liquid resistance>
A pressure-sensitive adhesive sheet with a base of 50 mm long × 50 mm wide is pressure-bonded to a non-alkali glass (product name “Eagle XG” manufactured by Corning Co., Ltd.) 70 mm long × 150 mm wide using a squeegee to produce a test sample. did.
The test sample was allowed to stand for 30 minutes, then immersed in 5 cm deep water in a metal bat, allowed to stand for 1 hour, and the adherend and adhesive interface were visually observed from the glass side. Thus, the water resistance of each pressure-sensitive adhesive sheet was evaluated. All steps were performed in an environment of 23 ° C. and 50% RH (relative humidity).
A: No intrusion of water was observed.
B: The penetration of water into the edge was 2 mm or less, and after being taken out of the water and allowed to stand for 24 hours, it was restored to its original state.
C: Floating occurred at the end due to water entering the end.

  From Table 5, the pressure-sensitive adhesive sheets of Examples 1 to 4 are all excellent in balance in terms of air bleeding, pressure-sensitive adhesive properties, blister resistance, and liquid resistance compared to the pressure-sensitive adhesive sheets of Comparative Examples 1 to 4. I understand that.

FIG. 5A and FIGS. 6 to 12 are each an arbitrarily selected length of 8 mm on the surface (α) of the surface of the resin layer of the pressure-sensitive adhesive sheet produced in Examples 1 to 4 and Comparative Examples 1 to 4, respectively. It is the binarized image of the image obtained by imaging | photography the area | region (D) enclosed by the rectangle of 10 mm in width from the surface ((alpha)) side using a digital microscope.
That is, the vertical image of FIG. 5A and FIGS. 6 to 12 corresponds to “8 mm” in the vertical direction and “10 mm” in the horizontal direction. In these binarized images, the black portion is a flat surface and the white portion corresponds to a recess.

FIG. 5B is a cross-sectional image obtained by observing the cross section of the pressure-sensitive adhesive sheet produced in Example 1 using a scanning microscope. In addition, about the cross section of the adhesive sheet of Examples 2-4, it is similar to the cross-sectional image of FIG.
As also shown in the image of FIG. 5 (b), the surface (α) of the resin layer of the adhesive sheet of Examples 1 to 4 is arbitrarily selected in a region (D) surrounded by a rectangle of 8 mm in length × 10 mm in width. As a result of observation using a scanning microscope, the presence of a concave portion having a maximum height difference of 0.5 μm or more was confirmed.

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

1a, 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 (Xβ) mainly containing resin part (X)
(Xα) Layer mainly containing resin portion (X) (Xα)
(Y1) Layer (Y1) containing 15% by mass or more of the particle part (Y)
13, 130 Recesses 14, 14 'Flat surfaces 21, 22 Release material 50 Rectangular 100 Translucent adherend 100a Smooth surface 101 Adherent

Claims (20)

A pressure-sensitive adhesive sheet having a resin layer on a base material or a release material, and at least a surface (α) of the resin layer opposite to the side on which the base material or the release material is provided;
The surface (α) has a recess and a plurality of flat surfaces,
In a region (D) surrounded by an arbitrarily selected 8 mm long × 10 mm wide rectangle on the surface (α), there are a plurality of flat surfaces, and among the plurality of flat surfaces present in the region (D), About one or more flat surfaces (R) excluding a flat surface having a cumulative relative frequency of 30% or less obtained by adding a relative frequency from the smaller area of each flat surface,
The adhesive sheet whose average value (L / S) ratio (L / S) of area (S) [micrometer < ² >] of each flat surface (R) and perimeter (L) [micrometer] is 0.011-0.020. The average value of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] of each flat surface (R) is 0.013 to 0.018. The adhesive sheet as described. The ratio (L / S) of the area (S) [μm ² ] to the perimeter (L) [μm] of each of the one or more flat surfaces (R) and the skewness Sk value with respect to the normal distribution curve of − The pressure-sensitive adhesive sheet according to claim 1 or 2, which is 0.1 to 1.6. The difference between the maximum value and the median of the ratio (L / S) of the area (S) [μm ² ] and the peripheral length (L) [μm] of one or more flat surfaces (R) is 0.0010 to 0 The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, which is 0.018.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the flat surface has an irregular shape.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the concave portion has a maximum height difference of 0.5 µm or more.   The surface (α) of the resin layer has at least one flat surface (f1) having a width capable of selecting a region surrounded by a circle having a diameter of at least 100 μm. The pressure-sensitive adhesive sheet described in 1. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein at least one flat surface (f2) having an area of 0.2 mm ² or more is present on the surface (α) of the resin layer.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 8, wherein the recess is not formed using a release material having an emboss pattern.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 9, wherein the resin layer includes a resin portion (X) containing a resin and a particle portion (Y) made of fine particles.   The pressure sensitive adhesive sheet according to claim 10 whose mass retention after heating said resin layer at 800 ° C for 30 minutes is 3-90 mass%.   The pressure sensitive adhesive sheet according to claim 10 or 11 in which said resin contained in resin part (X) contains adhesive resin.   The pressure-sensitive adhesive sheet according to any one of claims 11 and 12, wherein the resin portion (X) further contains one or more selected from a metal chelate crosslinking agent and an epoxy crosslinking agent.   The pressure-sensitive adhesive sheet according to any one of claims 11 to 13, wherein the fine particles are one or more selected from silica particles, metal oxide particles, and smectites.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 14, wherein the surface (β) of the resin layer on the side on which the base material or release material is provided has adhesiveness.   From the side on which the base material or release material is provided, the resin layer mainly includes a layer (Xβ) containing a resin part (X), a layer (Y1) containing 15% by mass or more of a particle part (Y), and mainly The pressure-sensitive adhesive sheet according to any one of claims 1 to 15, which is a multilayer structure in which layers (Xα) including a resin portion (X) are laminated in this order. The layer (Xβ) is a layer formed of a composition (xβ) containing a resin and having a fine particle content of less than 15% by mass,
The layer (Y1) is a layer formed from a composition (y) containing 15% by mass or more of fine particles,
The pressure-sensitive adhesive sheet according to claim 16, wherein the layer (Xα) is a layer formed of a composition (xα) containing a resin and containing a fine particle of less than 15% by mass. It is a method of manufacturing the adhesive sheet as described in any one of Claims 1-15, Comprising: The manufacturing method of an adhesive sheet which has the following process (1) and (2) at least.
Step (1): a coating film (x ′) comprising a composition (x) containing a resin and having a fine particle content of less than 15% by mass, and a coating film comprising a composition (y) comprising 15% by mass or more of fine particles Step (2) for forming (y ′): Step of simultaneously drying the coating film (x ′) and the coating film (y ′) formed in Step (1) It is a method of manufacturing the adhesive sheet of Claim 17, Comprising: The manufacturing method of an adhesive sheet which has the following process (1A) and (2A) at least.
Step (1A): a coating film (xβ ′) composed of a composition (xβ) containing a resin and having a fine particle content of less than 15% by mass on the substrate or the release material, and a composition containing 15% by mass or more of the fine particles. A coating film (y ′) made of the product (y) and a coating film (xα ′) made of a composition (xα) containing a resin and containing fine particles of less than 15% by mass are laminated in this order. Step (2A): A step of simultaneously drying the coating film (xβ ′), the coating film (y ′), and the coating film (xα ′) formed in the step (1A). It is a method of manufacturing the adhesive sheet of Claim 17, Comprising: The manufacturing method of an adhesive sheet which has the following process (1B) and (2B) at least.
Step (1B): a coating film comprising a composition (y) containing 15% by mass or more of the fine particles on a layer (Xβ) mainly containing a resin portion (X) provided on a substrate or a release material ( Step (2B) for forming a coating film (xα ′) comprising y ′) and a composition (xα) containing a resin and having a fine particle content of less than 15% by mass in this order: Step (1B) ) The step of simultaneously drying the coating film (y ′) and the coating film (xα ′) formed in

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