Adhesive sheet, laminated body for image display device, adhesive sheet roll body set, and method for manufacturing adhesive sheet with release film

Abstract

From the viewpoint of followability to a height difference or the like, as a new adhesive sheet of 300 μm or more or more as a thick adhesive sheet, an adhesive sheet is provided which is an adhesive sheet having an adhesive layer (X1) and an adhesive layer (X2) each containing an adhesive component derived from a (meth)acrylic polymer (A), the total thickness of the adhesive sheet is 300 μm or more, the thickness of each of the adhesive layer (X1) and the adhesive layer (X2) is 100 μm or more, and the ratio (x2 / x1) of the thickness (x2) of the adhesive layer (X2) to the thickness (x1) of the adhesive layer (X1) is 1 to 3.

Description

Technical Field

[0001] The present invention relates to adhesive sheets, laminates for image display devices using the adhesive sheets, adhesive sheet winding assembly having two adhesive sheet winding bodies with release films, and a method for manufacturing adhesive sheets with release films using the adhesive sheet winding assembly. Background Technology

[0002] In image display modules of electronic devices such as mobile portable terminals, computer monitors, and touch panels, glass or plastic films are laminated as surface protective layers. These surface protective layers are fixed to the image display module or touch panel by applying frame-shaped tape or adhesive to the outer blank area of ​​the image display portion or the outer side of the effective operating area of ​​the touch panel. As a result, a gap is formed between the effective operating area of ​​the image display portion or touch panel and the surface protective layer.

[0003] Replacing the gap between the image display module or touch panel and the surface protective layer with a transparent material whose refractive index is roughly the same as these materials, thereby increasing transmittance and improving image clarity, has become an industry trend. Examples of transparent materials used in this process include adhesives, bonding agents, and silicone.

[0004] When using adhesives as the transparent material, for example, in cases where defects occur after bonding the surface protective layer to the image display module, there is a problem of difficulty in peeling off the surface protective layer for replacement. Furthermore, when using silicone, long-term reliability is questionable due to its low adhesive strength. In contrast, adhesives, especially adhesive sheets, have sufficient adhesive strength and can be re-attached, making them effective for bonding surface protective layers to image display modules or touch panels.

[0005] The surfaces of adhered components, such as image display modules, optical parts, and surface protective layers, are sometimes uneven. On the surface of the surface protective layer, especially the surface in contact with the adhesive sheet, printing is often performed for decorative or light-shielding purposes. In some cases, due to the printing, height differences exceeding 10 μm are created on the surface of the surface protective layer. When using adhesive sheets to bond image display modules or touch panels to the surface protective layer, problems arise such as insufficient tracking of height differences by the adhesive sheet, resulting in gaps at or near the height difference. Furthermore, excessive stress caused by deformation of the adhesive sheet can potentially cause color unevenness in liquid crystal displays. To avoid these problems, the thickness of the adhesive sheet is typically set to approximately 10 times the height of the height difference.

[0006] From the perspective of following the height difference, sometimes thick films are required for adhesive sheets, such as adhesive sheets with a thickness of 300 μm or more.

[0007] Regarding adhesive sheets for thick films, for example, Patent Document 1 discloses adhesive sheets with thicknesses of 0.05 to 2 mm, and more specifically, adhesive sheets with thicknesses of 500 μm.

[0008] In addition, regarding adhesive sheets with a release film having a layered structure of release film / adhesive sheet / release film, double-sided adhesive sheets with a layered structure in which a light release film with relatively low peel strength and a heavy release film with relatively high peel strength are laminated on both sides of the adhesive layer (e.g., Patent Documents 2, 3, etc.).

[0009] For such a double-sided adhesive sheet with a laminated structure, the following processing steps can be illustrated: First, a light release film is peeled off, and one surface of the exposed adhesive layer is bonded to the object surface to be bonded. After this bonding, a heavy release film is further peeled off, and the other surface of the exposed adhesive layer is bonded to the different object surfaces, thereby bonding the objects together.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 2003-336013

[0013] Patent Document 2: Japanese Patent Application Publication No. 2016-180021

[0014] Patent Document 3: Japanese Patent Application Publication No. 2016-188266 Summary of the Invention

[0015] The problem the invention aims to solve

[0016] As mentioned above, from the viewpoint of following height differences, thick-film adhesive sheets are sometimes required, for example, adhesive sheets with a thickness of 300 μm or more.

[0017] However, when the adhesive sheet is too thick, specifically, when the thickness is more than 300μm, it can sometimes cause the following problems: it is difficult to make the adhesive sheet into a uniform sheet shape, or it is difficult to roll it into a roll for storage and transportation, or even if it can be temporarily rolled, it may cause poor appearance when stored in a roll for a certain period of time or when unwinding.

[0018] Additionally, in cases where it is desired to bond two adhesive sheets together to make the adhesive sheets thicker, for example, if two identical adhesive sheets with release films are bonded together using a layer structure of release film / adhesive sheet / release film, the peeling force of the release films on both sides is relatively the same, so it is expected that it will be difficult to peel off the release films.

[0019] Therefore, from the viewpoint of following height differences, the object of the present invention is to provide a thick film adhesive sheet, such as a new adhesive sheet of 300 μm or more, and a laminate for an image display device using the same.

[0020] Furthermore, the object of the present invention is to provide a new manufacturing method for an adhesive sheet with a release film that can be manufactured in a uniform sheet shape, has good storage stability, and allows for easy peeling of the release films on both sides, as a method for manufacturing an adhesive sheet with such a thick film, and an adhesive sheet winding assembly for use therein.

[0021] Solution for solving the problem

[0022] To address the aforementioned issues, the present invention provides an adhesive sheet, a laminate for an image display device using the adhesive sheet, an adhesive sheet winding assembly, and a method for manufacturing an adhesive sheet with a release film using the adhesive sheet winding assembly, comprising the following components.

[0023] [1] The first aspect of the present invention is an adhesive sheet (also referred to as "the adhesive sheet of the present invention") having an adhesive layer (X1) and an adhesive layer (X2), wherein both the adhesive layer (X1) and the adhesive layer (X2) contain an adhesive component derived from a (meth)acrylic polymer (A), the total thickness of the adhesive sheet is 300 μm or more, the thickness of both the adhesive layer (X1) and the adhesive layer (X2) is 100 μm or more, and the ratio (x2 / x1) of the thickness (x2) of the adhesive layer (X2) to the thickness (x1) of the adhesive layer (X1) is 1 to 3.

[0024] [2] The second aspect of the present invention is an adhesive sheet according to the first aspect, wherein when the cross-section of the adhesive sheet of the present invention is observed by an electron microscope, the interface between the adhesive layer (X1) and the adhesive layer (X2) is observed.

[0025] [3] The third aspect of the present invention is an adhesive sheet according to the first or second aspect, wherein the energy storage modulus G' of the adhesive layer (X1) and the adhesive layer (X2) at a temperature of 25°C is both above 1 kPa and below 1000 kPa.

[0026] [4] The fourth aspect of the present invention is an adhesive sheet according to any one of the first to third aspects, wherein the energy storage modulus G' of the adhesive layer (X1) and the adhesive layer (X2) at a temperature of 60°C is both 0.1 kPa or more and 200 kPa or less.

[0027] [5] The fifth aspect of the present invention is an adhesive sheet according to any one of the first to fourth aspects, wherein the glass transition temperature (Tg) of the adhesive layer (X1) and the adhesive layer (X2) is both above -50°C and below 5°C.

[0028] [6] The sixth aspect of the present invention is a laminate for an image display device, which has a structure in which two optical components are laminated by means of an adhesive sheet of any one of the first to fifth aspects, wherein the size of the optical components is 10 inches or more and 100 inches or less.

[0029] [7] The seventh aspect of the present invention is an adhesive sheet winding assembly, which includes:

[0030] An adhesive sheet roll (Z1) with a layered structure having a release film (Y1) / adhesive layer (X1) / release film (Y3) and an adhesive sheet roll with a release film; and

[0031] An adhesive sheet roll (Z2) with a layered structure consisting of a release film (Y2) / adhesive layer (X2) / release film (Y4) and a release film.

[0032] The peel force (α1) between the release film (Y1) and the adhesive layer (X1) is greater than the peel force (α3) between the release film (Y3) and the adhesive layer (X1).

[0033] The peel force (α2) between the release film (Y2) and the adhesive layer (X2) is greater than the peel force (α4) between the release film (Y4) and the adhesive layer (X2).

[0034] The peel force ratio (α1 / α2) of the peel force (α1) of the release film (Y1) / adhesive layer (X1) to the peel force (α2) of the release film (Y2) / adhesive layer (X2) is 1.1 or more.

[0035] [8] An eighth aspect of the present invention is an adhesive sheet winding assembly according to the seventh aspect, wherein both the adhesive layer (X1) and the adhesive layer (X2) contain an adhesive component derived from a (meth)acrylic polymer (A).

[0036] [9] The ninth aspect of the present invention is an adhesive sheet winding assembly according to the seventh or eighth aspect, wherein the thickness of the adhesive layer (X1) and the adhesive layer (X2) is 100 μm or more.

[0037]

[10] The tenth aspect of the present invention is an adhesive sheet winding assembly according to any one of the seventh to ninth aspects, wherein the energy storage modulus G' of the adhesive layer (X1) and the adhesive layer (X2) at a temperature of 25°C is 1 kPa or more and 1000 kPa or less.

[0038]

[11] The eleventh aspect of the present invention is an adhesive sheet winding assembly according to any one of the seventh to tenth aspects, wherein the energy storage modulus G' of the adhesive layer (X1) and the adhesive layer (X2) at a temperature of 60°C is 0.1 kPa or more and 200 kPa or less.

[0039]

[12] The twelfth aspect of the present invention is an adhesive sheet winding assembly according to any one of the seventh to eleventh aspects, wherein the glass transition temperature (Tg) of the adhesive layer (X1) and the adhesive layer (X2) is both -50°C or higher and 5°C or lower.

[0040]

[13] The thirteenth aspect of the present invention is a method for manufacturing an adhesive sheet with a release film, wherein:

[0041] A sheet winding body (Z1) comprising: an adhesive sheet with a release film having a layer structure of release film (Y1) / adhesive layer (X1) / release film (Y3) and the peel force (α1) between the release film (Y1) and the adhesive layer (X1) being greater than the peel force (α3) between the release film (Y3) and the adhesive layer (X1); and

[0042] A sheet winding body (Z2) comprising: an adhesive sheet with a release film having a layer structure of release film (Y2) / adhesive layer (X2) / release film (Y4) and the peel force (α2) between the release film (Y2) and the adhesive layer (X2) being greater than the peel force (α4) between the release film (Y4) and the adhesive layer (X2).

[0043] The adhesive surface of the adhesive layer (X1), which forms a release film (Y1) / adhesive layer (X1) by unwinding the sheet winding body (Z1) and peeling off the release film (Y3), is bonded with the adhesive surface of the adhesive layer (X2), which forms a release film (Y2) / adhesive layer (X2) by unwinding the sheet winding body (Z2) and peeling off the release film (Y4), thereby producing an adhesive sheet with a release film having a layer structure of release film (Y1) / adhesive layer (X1) / adhesive layer (X2) / release film (Y2).

[0044]

[14] The fourteenth aspect of the present invention is a method for manufacturing an adhesive sheet with a release film according to the thirteenth aspect, wherein the peel force ratio (α1 / α2) of the release film (Y1) / adhesive layer (X1) to the peel force ratio (α2) of the release film (Y2) / adhesive layer (X2) is 1.1 or more.

[0045] The effects of the invention

[0046] The adhesive sheet proposed in this invention (adhesive sheet of this invention) has a total thickness of 300 μm or more, which enables good tracking of height differences with large height differences.

[0047] Furthermore, according to the manufacturing method of the adhesive sheet with release film proposed in this invention, for example, two or more adhesive layers (X1) and (X2) with a thickness of more than 100 μm are prepared and these adhesive layers (X1) and (X2) are bonded together to form the adhesive sheet of this invention with an interface. Therefore, each adhesive layer (X1) and (X2) can be made uniform, and a winding body suitable for storage and transportation can be made, thus ensuring good storage stability.

[0048] Furthermore, by making the peel force (α1) between the release film (Y1) and the adhesive layer (X1) greater than the peel force (α2) between the release film (Y2) and the adhesive layer (X2), the release films on both sides can be easily peeled off. Detailed Implementation

[0049] Hereinafter, an example of an embodiment of the present invention will be described. However, the present invention is not limited to the embodiment described below.

[0050] <Adhesive sheet of the present invention>

[0051] An example of an adhesive sheet (referred to as "the adhesive sheet of the present invention") is an adhesive sheet having an adhesive layer (X1) and an adhesive layer (X2).

[0052] As described above, from the viewpoint of adaptability to large height differences, the total thickness of the adhesive sheet of the present invention is preferably 300 μm or more, more preferably 350 μm or more, more preferably 400 μm or more, and more preferably 450 μm or more. There is no particular upper limit, but from the viewpoint of suppressing the thickness of an image display device when using the adhesive sheet of the present invention to manufacture such a device, it is preferably 2000 μm or less, more preferably 1000 μm or less.

[0053] Preferably, the interface between the adhesive layer (X1) and the adhesive layer (X2) can be observed when the cross-section of the adhesive sheet is observed using an electron microscope. That is, when the cross-section of the adhesive sheet of the present invention is observed using an electron microscope, it is preferable that at least one interface extending parallel to the sheet surface can be observed.

[0054] It should be noted that the adhesive sheet of the present invention can be any adhesive sheet having the aforementioned interface; for example, the desired interface can be formed by bonding the adhesive sheets together. On the other hand, this is different from the case where the same material is laminated by extrusion molding, where the interface between layers cannot be observed.

[0055] The thickness of both adhesive layer (X1) and adhesive layer (X2) is preferably 100 μm or more.

[0056] If the thickness of each of the adhesive layer (X1) and the adhesive layer (X2) is 100 μm or more, the total thickness of the adhesive sheet of the present invention can be increased. Therefore, the thickness of both the adhesive layer (X1) and the adhesive layer (X2) is preferably 100 μm or more, and may also be 150 μm or more, and may also be 200 μm or more. On the other hand, if the thickness of each is too thick, as mentioned above, it will cause problems such as difficulty in rolling into rolls for storage and transportation, or poor appearance during unwinding. Therefore, the thickness of both the adhesive layer (X1) and the adhesive layer (X2) is preferably 300 μm or less, more preferably 250 μm or less, and even more preferably 200 μm or less.

[0057] The thicknesses of the adhesive layer (X1) and the adhesive layer (X2) can be the same or different from each other, and the ratio (x2 / x1) of the thickness of the adhesive layer (X2) to the thickness (x1) of the adhesive layer (X1) is preferably 1 to 3.

[0058] If the ratio (x2 / x1) is 3 or less, the number of adhesive layers can be reduced, that is, the number of lamination interfaces of the adhesive layers can be reduced, and the thickness of the adhesive sheet can be increased, which is therefore preferred. From this point of view, the ratio (x2 / x1) is preferably 3 or less, more preferably 2 or less, and even more preferably 1.5 or less.

[0059] Both adhesive layers (X1) and (X2) preferably contain adhesive components derived from (meth)acrylic polymers (A).

[0060] When both adhesive layers (X1) and adhesive layers (X2) contain adhesive components derived from (meth)acrylic polymers (A), sufficient adhesive strength can be obtained, which is therefore preferred.

[0061] It should be noted that the term "adhesive component derived from (meth)acrylic polymer (A)" means an adhesive component made from (meth)acrylic polymer (A), and that it contains at least (meth)acrylic polymer (A) or reactants of (meth)acrylic polymer (A), such as a cross-linked body formed by cross-linking (meth)acrylic polymer (A).

[0062] The preferred composition of the adhesive layer (X1) and adhesive layer (X2) is the same as that of the adhesive layer (X1) and adhesive layer (X2) of the adhesive sheet with release film of the present invention, which will be described later.

[0063] The adhesive layer (X1) and adhesive layer (X2) in the adhesive sheet of the present invention are preferably bonded together.

[0064] As an example of the adhesive sheet of the present invention, a case in which an adhesive layer (X1) and an adhesive layer (X2) are provided as layers on the surface and back side, and the thickness of the adhesive layer (X1) and the thickness of the adhesive layer (X2) are both 100 μm or more.

[0065] At this time, the adhesive sheet of the present invention can be a two-layer structure consisting of an adhesive layer (X1) and an adhesive layer (X2), or it can be a multi-layer structure with three or more layers, having an intermediate layer consisting of one or more layers between the adhesive layers (X1) and the adhesive layers (X2). Furthermore, the thickness of each layer of the adhesive layers (X1) and (X2) can be the same or different, and can be 100 μm or more, or 200 μm or more. On the other hand, if the thickness of each layer is too thick, as mentioned above, problems will arise such as difficulty in producing a uniform sheet, difficulty in rolling it into a roll for storage and transportation, or poor appearance during unwinding. Therefore, from this viewpoint, a thickness of 300 μm or less is preferred, more preferably 250 μm or less, and more preferably 200 μm or less.

[0066] [Storage Modulus (G')]

[0067] When both the adhesive layer (X1) and adhesive layer (X2) in the adhesive sheet of the present invention, i.e., the laminated adhesive layer (X1) and adhesive layer (X2), are composed of a solvent-free system, from the viewpoint of imparting adhesive strength and reliability, the storage modulus (G') at a temperature of 25°C is preferably 1 kPa or more, more preferably 10 kPa or more, and even more preferably 20 kPa or more. On the other hand, when composed of a solvent-free system, from the viewpoint of improving contour following ability, it is preferably 1000 kPa or less, more preferably 500 kPa or less, more preferably 200 kPa or less, and even more preferably 100 kPa or less.

[0068] Based on the same viewpoint described above, the energy storage modulus (G') of each layer of the laminated adhesive layer (X1) and adhesive layer (X2) at 60°C is preferably 0.1 kPa or more, more preferably 1 kPa or more, and even more preferably 5 kPa or more. On the other hand, it is preferably 200 kPa or less, more preferably 100 kPa or less, more preferably 60 kPa or less, and even more preferably 30 kPa or less.

[0069] To adjust the storage modulus (G') of the adhesive layers (X1) and (X2) in the adhesive sheet of the present invention to the above-mentioned ranges at temperatures of 25°C and 60°C, the composition, molecular weight, or glass transition temperature (Tg) of the main component resin (base polymer) of the adhesive layers (X1) and (X2) can be adjusted, or the mixing ratio of the crosslinking agent and initiator used in the manufacture of the adhesive layers (X1) and (X2) can be adjusted. However, it is not limited to this.

[0070] [Glass transition temperature (Tg)]

[0071] When both adhesive layers (X1) and (X2) in the adhesive sheet of the present invention, i.e., adhesive layers (X1) and (X2) in a laminated state, are composed of a solvent-free system, from the viewpoint of improving adhesive strength, the glass transition temperature (Tg) is preferably -50°C or higher, more preferably -40°C or higher, and even more preferably -30°C or higher. On the other hand, when composed of a solvent-free system, from the viewpoint of improving conformability to unevenness, the temperature is preferably 5°C or lower, more preferably 0°C or lower, even more preferably -10°C or lower, and even more preferably -20°C or lower.

[0072] To adjust the glass transition temperature (Tg) of the adhesive layer (X1) and adhesive layer (X2) in the adhesive sheet of the present invention to the above-mentioned range, the composition, molecular weight, or glass transition temperature (Tg) of the main component resin (base polymer) of the adhesive layer (X1) and adhesive layer (X2) can be adjusted, or the mixing ratio of the crosslinking agent and initiator used in the manufacture of the adhesive layer (X1) and adhesive layer (X2) can be adjusted. However, it is not limited to this.

[0073] It should be noted that the glass transition temperature (Tg) of the adhesive layer (X1) and adhesive layer (X2) in the adhesive sheet of the present invention is the glass transition temperature (Tg) defined by the peak temperature of the loss tangent (Tanδ) obtained by dynamic viscoelasticity measurement.

[0074] [Gel fraction]

[0075] In the adhesive sheet of the present invention, the gel fraction of adhesive layer (X1) and adhesive layer (X2), i.e., the laminated adhesive layer (X1) and adhesive layer (X2), is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more. On the other hand, from the viewpoint of improving the conformability of the surface during bonding, it is preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less.

[0076] To adjust the gel fraction of adhesive layers (X1) and (X2) in the adhesive sheet of the present invention to the range described above, it is only necessary to adjust the type and amount of crosslinking agent and initiator, as well as the amount of UV irradiation. However, it is not limited to this.

[0077] The adhesive sheet of the present invention can be provided and used alone, or it can be provided as an adhesive sheet with a release film as described below, which can be used after the release film is peeled off. Furthermore, it can also be provided with a component to be adhered, such as an optical component, attached to one or both sides.

[0078] <The adhesive sheet with a release film of the present invention>

[0079] An example of an embodiment of the present invention is an adhesive sheet with a release film (referred to as "the adhesive sheet with a release film of the present invention") having a layer structure of release film (Y1) / adhesive sheet of the present invention / release film (Y2), such as a layer structure of release film (Y1) / adhesive layer (X1) / adhesive layer (X2) / release film (Y2).

[0080] It should be noted that, in this invention, when referred to as "release film (Y1) / adhesive sheet of this invention / release film (Y2)", it indicates a stacked structure formed by sequentially layering the release film (Y1), the adhesive sheet of this invention, and the release film (Y2). The same applies to other cases.

[0081] Regarding the peel force ratio (α1 / α2) of the release film (Y1) / adhesive layer (X1) to the peel force (α2) of the release film (Y2) / adhesive layer (X2), from the viewpoint of ease of peeling of the release film (Y1) and the release film (Y2), it is preferably 1.1 or more, more preferably 1.3 or more, more preferably 1.5 or more, more preferably 1.8 or more, more preferably 2.0 or more, and even more preferably 2.3 or more. On the other hand, from the viewpoint of ease of peeling of the release film (Y2), it is preferably 20 or less, more preferably 10 or less, more preferably 6 or less, and more preferably 3 or less.

[0082] From the viewpoint of operability when peeling off the release film (Y1) or preventing the release film from peeling off during roller storage, the peeling force (α1) is preferably 0.02 N / cm or more, particularly preferably 0.05 N / cm or more, and even more preferably 0.08 N / cm or more. On the other hand, from the viewpoint of ease of peeling off the release film (Y1) after the adhered objects are bonded, it is preferably 0.40 N / cm or less, particularly preferably 0.30 N / cm or less, and even more preferably 0.20 N / cm or less.

[0083] From the viewpoint of operability when peeling off the release film (Y2) or to prevent peeling of the release film during roller storage, the peeling force (α2) is preferably 0.02 N / cm or more, particularly preferably 0.04 N / cm or more, and even more preferably 0.18 N / cm or more. On the other hand, from the viewpoint of ease of peeling off the release film (Y2), it is preferably 0.40 N / cm or less, particularly preferably 0.25 N / cm or less, and even more preferably 0.18 N / cm or less.

[0084] It should be noted that in this invention, release films with relatively high peel strength are sometimes referred to as "heavy release films" or "heavy separators", while release films with relatively low peel strength are referred to as "light release films" or "light separators".

[0085] Regarding the adjustment methods for the peel force (α1) between the release film (Y1) and the adhesive layer (X1) and the peel force (α2) between the release film (Y2) and the adhesive layer (X2), for example, if the structure of each release film is such that a release layer is laminated on a substrate film, the peel force can be adjusted by the composition and thickness of the release layer, the thickness of the substrate film, etc. However, since release films with various peel forces are currently available on the market, by purchasing and using a release film with the desired peel force, the peel force (α1) and peel force (α2) can be adjusted separately. It should be noted that the method for adjusting the peel force between the release film and the adhesive sheet is the same in other cases.

[0086] As an example of the adhesive sheet with a release film according to the present invention, an adhesive sheet having a layer structure of release film (Y1) / adhesive layer (X1) / adhesive layer (X2) / release film (Y2) can be listed.

[0087] The adhesive layer (X1) is an adhesive layer formed from an adhesive sheet with a release film, having a layer structure of release film (Y1) / adhesive layer (X1) / release film (Y3) and the peel force (α1) between release film (Y1) and adhesive layer (X1) is greater than the peel force (α3) between release film (Y3) and adhesive layer (X1).

[0088] The adhesive layer (X2) is an adhesive layer formed from an adhesive sheet with a release film, having a layer structure of release film (Y4) / adhesive layer (X2) / release film (Y2) and the peel force (α2) between the release film (Y2) and the adhesive layer (X2) being greater than the peel force (α4) between the release film (Y4) and the adhesive layer (X2).

[0089] Furthermore, as described above, the peel force (α1) between the release film (Y1) and the adhesive layer (X1) is greater than the peel force (α2) between the release film (Y2) and the adhesive layer (X2).

[0090] In the case of the structure described above, the adhesive layer (X1) can be peeled off from the release film (Y3) serving as a light separator from the layer structure of the release film (Y1) / adhesive layer (X1) / release film (Y3) to form a structure of release film (Y1) / adhesive layer (X1).

[0091] On the other hand, the adhesive layer (X2) is peeled from the release film (Y4) which serves as a light separator in the layer structure of the release film (Y4) / adhesive layer (X2) / release film (Y2) to form the structure of the release film (Y2) / adhesive layer (X2).

[0092] The adhesive surface of the adhesive layer (X1) of the release film (Y1) / adhesive layer (X1) structure is bonded to the adhesive surface of the adhesive layer (X2) of the release film (Y2) / adhesive layer (X2) structure to form a release film (Y1) / adhesive layer (X1) + adhesive layer (X2) / release film (Y2).

[0093] Alternatively, the adhesive surfaces of the adhesive layer (X1) of the release film (Y1) / adhesive layer (X1) structure and the adhesive surfaces of the adhesive layer (X2) of the release film (Y2) / adhesive layer (X2) structure can be bonded to the adhesive layer of the intermediate layer to form a release film (Y1) / adhesive layer (X1) + adhesive layer of the intermediate layer + adhesive layer (X2) / release film (Y2).

[0094] At this point, from the viewpoint of ease of peeling off the release film (Y1) and the release film (Y2), the peel force ratio (α1 / α2) of the peel force (α1) of the release film (Y1) / adhesive layer (X1) to the peel force (α2) of the release film (Y2) / adhesive layer (X2) is preferably 1.1 or more, more preferably 1.3 or more, more preferably 1.5 or more, more preferably 1.8 or more, more preferably 2.0 or more, and even more preferably 2.3 or more. On the other hand, from the viewpoint of ease of peeling off the release film (Y2), it is preferably 20 or less, more preferably 10 or less, more preferably 6 or less, and more preferably 3 or less.

[0095] Furthermore, from the viewpoint of ease of peeling each release film, the peel force ratio (α1 / α3) of the peel force (α1) to the peel force (α3), and the peel force ratio (α2 / α4) of the peel force (α2) to the peel force (α4) are preferably 1.1 or more, more preferably 1.3 or more, more preferably 1.5 or more, more preferably 1.8 or more, more preferably 2.0 or more, and even more preferably 2.3 or more. On the other hand, from the viewpoint of ease of peeling the release film (Y2), it is preferably 20 or less, more preferably 10 or less, more preferably 6 or less, and more preferably 3 or less.

[0096] Furthermore, from the viewpoint of storage stability under the roller shape or the processability during the peeling of the release film, the peeling force (α1) is preferably 0.02 to 0.40 N / cm, more preferably 0.05 N / cm or more or 0.30 N / cm or less, and even more preferably 0.08 N / cm or more or 0.20 N / cm or less.

[0097] From the viewpoint of storage stability under roller shape or processability during peeling of release film, the peeling force (α3) is preferably 0.01 to 0.20 N / cm, more preferably 0.02 N / cm or more or 0.15 N / cm or less, and even more preferably 0.03 N / cm or more or 0.10 N / cm or less.

[0098] Furthermore, from the viewpoint of storage stability under the roller shape or the processability during the peeling of the release film, the peeling force (α2) is preferably 0.02 N / cm or more or 0.40 N / cm or less, more preferably 0.04 N / cm or more or 0.25 N / cm or less, and even more preferably 0.06 N / cm or more or 0.18 N / cm or less.

[0099] From the viewpoint of storage stability under roller shape or processability during peeling of release film, the peeling force (α4) is preferably 0.01 to 0.20 N / cm, more preferably 0.02 N / cm or more or 0.15 N / cm or less, and even more preferably 0.03 N / cm or more or 0.10 N / cm or less.

[0100] [Storage Modulus (G')]

[0101] In the adhesive sheet with release film of the present invention, when the adhesive layers (X1) and (X2) are made of a solvent-free system, from the viewpoint of imparting adhesive strength and reliability, the storage modulus (G') at a temperature of 25°C is preferably 1 kPa or more, more preferably 10 kPa or more, and even more preferably 20 kPa or more. On the other hand, when made of a solvent-free system, from the viewpoint of improving contour following, it is preferably 1000 kPa or less, more preferably 500 kPa or less, more preferably 200 kPa or less, and even more preferably 100 kPa or less.

[0102] Based on the same viewpoint described above, the energy storage modulus (G') at 60°C is preferably 0.1 kPa or more, more preferably 1 kPa or more, and even more preferably 5 kPa or more. On the other hand, it is preferably 200 kPa or less, more preferably 100 kPa or less, more preferably 60 kPa or less, and even more preferably 30 kPa or less.

[0103] To adjust the storage modulus (G') of the adhesive layers (X1) and (X2) at temperatures of 25°C or 60°C to the range described above, the composition, molecular weight, or Tg of the main component resin (base polymer) can be adjusted, or the mixing ratio of the crosslinking agent and initiator can be adjusted. However, this is not a limitation.

[0104] [Glass transition temperature (Tg)]

[0105] In the adhesive sheet with release film of the present invention, when the adhesive layers (X1) and (X2) are made of a solvent-free system, from the viewpoint of improving adhesion, the glass transition temperature (Tg) is preferably -50°C or higher, more preferably -40°C or higher, and even more preferably -30°C or higher. On the other hand, when made of a solvent-free system, from the viewpoint of improving contour following, the temperature is preferably 5°C or lower, more preferably 0°C or lower, even more preferably -10°C or lower, and even more preferably -20°C or lower.

[0106] To adjust the glass transition temperature (Tg) of adhesive layers (X1) and (X2) to the range described above, the composition, molecular weight, or Tg of the main component resin (base polymer) can be adjusted, or the proportions of the crosslinking agent and initiator can be adjusted. However, this is not a limitation.

[0107] It should be noted that the glass transition temperature (Tg) of the adhesive layer (X1) and adhesive layer (X2) is defined by the peak temperature of the loss tangent (Tanδ) obtained by dynamic viscoelasticity measurement.

[0108] [Gel fraction]

[0109] From the viewpoint of improving the reliability after bonding, the gel content of the adhesive layer (X1) and adhesive layer (X2) in the adhesive sheet with release film of the present invention is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more. On the other hand, from the viewpoint of improving the conformability of the surface during bonding, it is preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less.

[0110] (composition)

[0111] The composition of adhesive layers (X1) and (X2) is arbitrary, as long as they possess adhesive strength. They can also be bonded by applying pressure or heat as needed.

[0112] In addition, adhesive layer (X1) and adhesive layer (X2) can be of the same composition or different compositions.

[0113] It should be noted that the adhesive layer (X1) and adhesive layer (X2) are also collectively referred to as "this adhesive sheet".

[0114] The adhesive layers (X1) and (X2) can be pressure-sensitive adhesive sheets, heat-curing adhesive sheets, or UV-curing adhesive sheets. From the perspectives of simplicity of the curing process and stability of the cured properties, solvent-free adhesive sheets formed from solvent-free resin compositions, and specifically UV-curing adhesive sheets, are preferred. Examples include UV-curing adhesive sheets that are cured in one step to achieve sheet retention and adhesion, and UV-curing adhesive sheets that are temporarily cured to allow for eventual UV curing.

[0115] (Main component: resin)

[0116] The main component resins of adhesive layer (X1) and adhesive layer (X2) can be the same resin or different resins.

[0117] Both adhesive layers (X1) and (X2) preferably contain (meth)acrylic polymers as the main component resin.

[0118] However, as described above, the (meth)acrylic polymer used as the main component resin of the adhesive layer (X1) and the adhesive layer (X2) is preferably derived from (meth)acrylic polymer (A).

[0119] Here, "main component resin" refers to the resin with the highest mass proportion among the resins constituting each layer. The content of this main component resin is not particularly limited, and it is conceivable that it accounts for 50% or more of the resin (100% by mass) constituting adhesive layer (X1) or adhesive layer (X2), of which it accounts for 60% or more of the resin, of which it accounts for 70% or more of the resin, of which it accounts for 80% or more of the resin, of which it accounts for 90% or more of the resin, of which it accounts for 95% or more of the resin, of which it accounts for 100% by mass.

[0120] Furthermore, in this invention, "resin" refers to polymer, in other words, a polymer (including copolymers), including polymers and oligomers. As for molecular weight, it includes, for example, a weight-average molecular weight of 10,000 or more, preferably 50,000 or more, and more preferably 100,000 or more.

[0121] [(Meth)acrylic polymer (A)]

[0122] When the (meth)acrylic polymer (A), which is the main component resin (base polymer) of the adhesive layer (X1) and the adhesive layer (X2), is solvent-free, the weight-average molecular weight is preferably 100,000 to 1,000,000, more preferably 200,000 or more or 800,000 or less, and even more preferably 300,000 or more or 600,000 or less.

[0123] From the viewpoint of balancing surface conformability and adhesion, the glass transition temperature (Tg) of the (meth)acrylic polymer (A) is preferably -50 to 5°C, more preferably above -40°C or below 0°C, more preferably above -35°C or below -10°C, and more preferably above -30°C or below -20°C.

[0124] In this invention, "(meth)acrylic polymer" means including acrylic homopolymers, methacrylic homopolymers, acrylic copolymers and methacrylic copolymers; "(meth)acrylate" means including acrylates and methacrylates; and "(meth)acryloyl" means including acryloyl groups and methacryloyl groups.

[0125] The (meth)acrylate polymer (A) substantially does not contain structural units derived from carboxyl-containing (meth)acrylate monomers as copolymerizing components, and as monomeric components constituting the copolymer, it preferably contains: a low-Tg (meth)acrylate monomer (a1) with a glass transition temperature (Tg) of less than -30°C when forming a homopolymer; and a (meth)acrylate monomer (a2) containing a polar group selected from the group consisting of hydroxyl-containing (meth)acrylate monomers and nitrogen-containing (meth)acrylate monomers.

[0126] Here, the aforementioned "structural units that do not substantially contain (meth)acrylate monomers derived from carboxyl groups" includes not only cases where there are no structural units derived from (meth)acrylate monomers at all, but also cases where (meth)acrylate copolymers contain structural units derived from (meth)acrylate monomers at a rate of 0.5% by mass or less, preferably 0.1% by mass or less.

[0127] Examples of carboxyl-containing (meth)acrylate monomers include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, citraconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

[0128] [Low Tg (meth)acrylate monomer (a1)]

[0129] Examples of low-Tg (meth)acrylate monomers (a1) with a glass transition temperature (Tg) of less than -30°C when forming the above homopolymers include: 2-ethylhexyl acrylate (Tg: -70°C), n-butyl acrylate (Tg: -55°C), n-octyl (meth)acrylate (Tg: -65°C), isooctyl acrylate (Tg: -54°C), nonyl acrylate (Tg: -37°C), isononyl acrylate (Tg: -58°C), isodecanyl acrylate (Tg: -60°C), isodecanyl methacrylate (Tg: -41°C), tridecyl acrylate (Tg: -55°C), tridecyl methacrylate (Tg: -40°C), lauryl methacrylate (Tg: -65°C), 2-ethoxyethyl methacrylate (Tg: -31°C), and ethoxyethoxyethyl acrylate (ethyl carbitol acrylate) (Tg: -67°C). From the perspective of glass transition temperature and monomer versatility, the copolymer component mentioned above preferably includes at least one selected from 2-ethylhexyl acrylate and n-butyl acrylate.

[0130] Of the total 100% by mass of all monomer components constituting the above-mentioned (meth)acrylic polymer (A), the low-Tg (meth)acrylic ester monomer (a1) preferably contains 30% by mass or more, and more preferably 40% by mass or more and 90% by mass or less from the viewpoint of adjusting the glass transition temperature when forming the copolymer, and particularly preferably 45% by mass or more or 80% by mass or less.

[0131] [(Meth)acrylate monomers containing polar groups (a2)]

[0132] For the hydroxyl-containing (meth)acrylate monomers that are (a2) containing polar groups, other than (a1) mentioned above, examples include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and methyl (4-hydroxymethylcyclohexyl)acrylate.

[0133] In addition, examples of nitrogen-containing (meth)acrylate monomers that are polar (meth)acrylate monomers (a2) mentioned above include: urethane (meth)acrylate, ethyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methacryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hydroxy (meth)acrylamide, etc.

[0134] Among these, from the viewpoint of imparting polarity to improve the glass transition temperature, monomer versatility, and adhesive properties, at least one of 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, and 6-hydroxyhexyl methacrylate is preferred as the hydroxyl-containing (meth)acrylate monomer.

[0135] Furthermore, from the viewpoint of imparting polarity to the nitrogen-containing (meth)acrylate monomer in order to improve the glass transition temperature, monomer versatility, and adhesive properties, it is preferable to use at least one selected from N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, and N-hydroxy (meth)acrylamide.

[0136] Of the total 100% by mass of all monomer components constituting the above-mentioned (meth)acrylic polymer (A), the above-mentioned (meth)acrylic ester monomer (a2) containing polar groups preferably contains 1% by mass or more, particularly preferably 3% by mass or more, especially from the viewpoint of imparting polarity in order to improve the glass transition temperature and adhesive properties during copolymerization, it is more preferably contained in a proportion of 5% by mass or more and 50% by mass or less, and particularly preferably contained in a proportion of 8% by mass or more or 30% by mass or less.

[0137] [Other Copolymer Components]

[0138] In the above-mentioned (meth)acrylic polymer (A), in addition to (a1) and (a2) mentioned above, straight-chain or branched alkyl (meth)acrylates with 4 to 18 carbon atoms (a3), epoxy-containing (meth)acrylate monomers (a4), and (meth)acrylate monomers with 1 to 3 carbon atoms (a5) can also be used as copolymer components constituting the copolymer.

[0139] Examples of straight-chain or branched alkyl (meth)acrylates (a3) ​​having 4 to 18 carbon atoms, other than those described in (a1) and (a2), include isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, neoamyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and isobornyl (meth)acrylate. One or more of these can be used in combination.

[0140] Of the total 100% by mass of all monomer components constituting the above-mentioned (meth)acrylic polymer (A), straight-chain or branched alkyl (meth)acrylates (a3) ​​having 4 to 18 carbon atoms are preferably contained in 3% by mass or more. In particular, from the viewpoint of adjusting the glass transition temperature during copolymerization, it is more preferable to contain 5% by mass or more and 50% by mass or less, and especially preferably 8% by mass or more or 30% by mass or less.

[0141] Examples of epoxy-containing (meth)acrylate monomers (a4) include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, 3,4-epoxycyclohexyl methyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate glycidyl ether, in addition to substances mentioned above (a1) and (a2). These may be one or a combination of two or more.

[0142] Of the total 100% by mass of all monomer components constituting the above-mentioned (meth)acrylic polymer (A), the above-mentioned epoxy-containing (meth)acrylic ester monomer (a4) preferably contains 1% by mass or more, and more preferably, from the viewpoint of imparting cohesive force and adhesive force to the adhesive sheet, it contains 2% by mass or more and 30% by mass or less, and particularly preferably, it contains 3% by mass or more or 15% by mass or less.

[0143] (a5) acrylate monomers having 1 to 3 carbon atoms as alkyl groups can include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, etc., which are substances other than those described in (a1) and (a2). They can be one type or a combination of two or more types.

[0144] The (meth)acrylate monomer (a5) having 1 to 3 carbon atoms in the alkyl group is preferably contained in 1% or more of the total 100% by mass of all monomer components constituting the (meth)acrylate polymer (A). In particular, from the viewpoint of adjusting the glass transition temperature during copolymerization, it is more preferably contained in a proportion of 3% or more and 50% or less by mass, and especially preferably in a proportion of 5% or more or 30% or less by mass.

[0145] From the viewpoint of adjusting the glass transition temperature and polarity during copolymerization to impart cohesive properties such as internal cohesion and adhesion, the above-mentioned (meth)acrylic acid polymer (A) is particularly preferred to be a copolymer of a 3-component system or even a 4-component system, which includes any of the above-mentioned (a3) ​​and / or (a5) as copolymer components constituting the copolymer, in addition to (a1) and (a2) above.

[0146] It should be noted that in this invention, when the glass transition temperature (Tg) of the above-mentioned copolymer components (a2) to (a5) is less than -30°C, they are treated as low Tg (meth)acrylate monomers (a1).

[0147] From the viewpoints of maintaining the shape of the adhesive sheet of the present invention, which has photocurability due to the cross-linked structure formed by the copolymers, from the viewpoints of having the shear storage modulus (G') of the adhesive sheet of the present invention at a temperature of 25°C within the above-mentioned range, and from the viewpoints of having the measured Tg of the adhesive sheet of the present invention within the above-mentioned range, the above-mentioned (meth)acrylic polymer (A) can form chemical bonds formed by hydroxyl groups and isocyanate groups or by amino groups and isocyanate groups.

[0148] More specifically, examples include: a method of heating or curing an adhesive resin composition of a (meth)acrylic polymer (A) containing a hydroxyl-containing (meth)acrylate as a copolymer and an isocyanate compound having an isocyanate group that reacts with the hydroxyl group, thereby forming a chemical bond between the functional groups; or, a method of heating or curing an adhesive resin composition of a (meth)acrylic polymer (A) containing an amino methacrylate as a copolymer and, similarly, an isocyanate compound having an isocyanate group that reacts with the amino group, thereby forming a chemical bond.

[0149] Examples of isocyanate compounds include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hydrogenated toluene diisocyanate, 1,3-phenylenedimethylene diisocyanate, 1,4-phenylenedimethylene diisocyanate, hexamethylene diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, tetramethylphenylenedimethylene diisocyanate, 1,5-naphthalene diisocyanate, and triphenylmethane triisocyanate.

[0150] Furthermore, the compounds containing isocyanate groups mentioned above may further possess radical polymerizable functional groups such as (meth)acryloyl groups, like 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate.

[0151] Thus, by giving the (meth)acrylic polymer (A) a free radical polymerizable functional group, and utilizing the cross-linking reaction between the (meth)acrylic polymers (A) based on the free radical polymerizable functional group, even without using carboxyl-containing (meth)acrylic ester monomers and cross-linking agents (B), it has the advantages of easily and efficiently improving the cohesive force after photocuring (cross-linking) and having excellent reliability, and is therefore more preferable.

[0152] Furthermore, from the same perspective as above, the aforementioned (meth)acrylic acid polymer (A) preferably has photocrosslinking structural sites. These photocrosslinking structural sites are those that, when excited by irradiation with active energy rays, undergo a hydrogen abstraction reaction, thereby generating free radicals.

[0153] More specifically, the photocrosslinking structural site is preferably selected from one or more of the following structures: benzophenone, benzoyl, o-benzoylbenzoate, thioxanthone, 3-coumarinone, 2-ethylanthraquinone, and camphorquinone.

[0154] By giving the above-mentioned (meth)acrylic polymer (A) such a photocrosslinkable structural site, the following advantages are achieved: the (meth)acrylic polymer (A) can be effectively cured (crosslinked) through the photocrosslinkable structural site; even without using carboxyl-containing (meth)acrylic ester monomers and crosslinking agents (B), the cohesive strength after photocuring (crosslinking) is easily and effectively improved, resulting in excellent reliability.

[0155] In order to have the above-mentioned photocrosslinking structural sites, the (meth)acrylate polymer (A) can use (meth)acrylate monomers with a benzophenone structure, such as 4-acryloyloxybenzophenone, 4-acryloyloxyethoxybenzophenone, 4-acryloyloxy-4'-methoxybenzophenone, 4-acryloyloxy-4'-bromobenzophenone, 4-acryloyloxyethoxy-4'-bromobenzophenone, 4-methacryloyloxybenzophenone, 4-methacryloyloxyethoxy-4'-bromobenzophenone, 4-methacryloyloxybenzophenone, 4-methacryloyloxy-4'-methoxybenzophenone, 4-methacryloyloxyethoxy-4'-bromobenzophenone, 4-methacryloyloxyethoxy-4'-bromobenzophenone, and mixtures thereof, as the copolymerizing component.

[0156] By using (meth)acrylate monomers with such photocrosslinking structural sites, it is possible to form photocrosslinking structural sites in (meth)acrylate polymers (A).

[0157] (Components other than the main resin component)

[0158] The adhesive layer (X1) and adhesive layer (X2) can be formed from an adhesive composition containing a base resin such as an acrylic polymer (A), a crosslinking agent (B) as needed, a photopolymerization initiator (C), a silane coupling agent (D), and other components such as rust inhibitors, tackifying resins, etc.

[0159] The adhesive layer (X1) and adhesive layer (X2) are preferably formed, for example, of an adhesive composition containing an acrylic polymer (A) and a hydrogen-abstracting photopolymerization initiator (C) as a photopolymerization initiator.

[0160] (Cross-linking agent (B))

[0161] As the aforementioned crosslinking agent (B), a crosslinking agent having at least one double bond crosslinking is preferred. Examples include crosslinking agents having at least one crosslinking functional group selected from (meth)acryloyl, epoxy, isocyanate, carboxyl, hydroxyl, carbodiimide, oxazoline, aziridinyl, vinyl, amino, imino, and amide groups. One or more crosslinking agents may be used.

[0162] Of the above, especially from the viewpoint of forming cross-linked structures between (meth)acrylic polymers (A), isocyanate compounds are particularly preferred as cross-linking agents (B).

[0163] In addition to the above, as a crosslinking agent (B), a photopolymerizable compound having carbon-carbon double bonds, especially a polyfunctional (meth)acrylate, is preferred.

[0164] Here, "multifunctional" refers to having two or more cross-linking functional groups.

[0165] It should be noted that, depending on the requirements, it can have more than three or four cross-linking functional groups.

[0166] As a crosslinking agent (B), by using polyfunctional (meth)acrylates, not only do the polyfunctional (meth)acrylates chemically bond with each other to form a chemically crosslinked structure consisting of a three-dimensional network structure, but also the movement of the polymer is constrained by the entanglement of the chain-like (meth)acrylate polymers with this three-dimensional network structure, thus forming a physical aggregate structure, i.e., a physical crosslinked structure.

[0167] Examples of the aforementioned polyfunctional (meth)acrylates include, for instance, polypropylene glycol dimethacrylate, 1,4-butanediol di(meth)acrylate, glycerol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerol glycidyl ether di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethacrylate, tricyclodecanediethanol di(meth)acrylate, and bisphenol A polyethoxydi(meth)acrylate. Acrylic esters, bisphenol A polypropoxy di(meth)acrylate, bisphenol F polyethoxy di(meth)acrylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, ε-caprolactone modified tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate Tetramethacrylate, propoxylated pentaerythritol tetramethacrylate, ethoxylated pentaerythritol tetramethacrylate, dipentaerythritol hexamethacrylate, polyethylene glycol dimethacrylate, tri(acryloyloxyethyl)isocyanurate, dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, tripentaerythritol hexamethacrylate, tripentaerythritol pentamethacrylate, neopentyl glycol hydroxypentanoate (meth)acrylate UV-curable multifunctional (meth)acrylate monomers such as di(meth)acrylates of esters, ε-caprolactone adducts of neopentyl glycol hydroxypentanoate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, and bis(trimethylolpropane)tetra(meth)acrylate, as well as multifunctional (meth)acrylate oligomers such as polyester (meth)acrylates, epoxy (meth)acrylates, urethane (meth)acrylates, and polyether (meth)acrylates. They can be used alone or in combination of two or more.

[0168] The amount of crosslinking agent (B) relative to 100 parts by weight of (meth)acrylic polymer (A) is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, particularly preferably 5 parts by weight or more, especially preferably 10 parts by weight or more, more preferably 100 parts by weight or less, more preferably 50 parts by weight or less, particularly preferably 30 parts by weight or less, and especially preferably 20 parts by weight or less.

[0169] The mass-average molecular weight of the crosslinking agent (B) is preferably 1000 or less, more preferably 50 or more or 800 or less, and even more preferably 100 or more or 600 or less.

[0170] The molecular weight of each reactive functional group in the crosslinking agent (B) is preferably 300 or less, more preferably 30 or more or 250 or less, and even more preferably 60 or more or 150 or less.

[0171] The crosslinking agent monomer has a crosslinking temperature Tg of 100°C or higher, preferably 200°C or higher.

[0172] By setting the crosslinking agent dosage, crosslinking agent molecular weight, molecular weight of each reactive functional group of the crosslinking agent, and crosslinking agent Tg to the ranges described above, the elastic modulus of the adhesive sheet of the present invention can be easily adjusted to the specified range, thus easily imparting die-cutting processability.

[0173] (Photopolymerization initiator (C))

[0174] The photopolymerization initiator (C) may include, for example, compounds that generate active free radical species by irradiation with ultraviolet light, visible light, or more specifically, light with wavelengths of 200 nm to 780 nm.

[0175] As described above, the photopolymerization initiator (C) can be either a pyrolysis-type photopolymerization initiator (C1) or a hydrogen-abstracting type photopolymerization initiator (C2). It can be used alone or in combination, and one or more of them can be used in combination.

[0176] From the viewpoint of adjusting the gel fraction to a specified range, it is preferable to use a hydrogen-abstracting photopolymerization initiator (c2) as the photopolymerization initiator (C).

[0177] Examples of cleavage-type photopolymerization initiators (C1) include: 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl one, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-[4-{4-(2-hydroxy-2-methyl-propanoyl)benzyl}phenyl]-2-methyl-propane-1-one, oligomer (2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propane), methyl phenylglyoxylate, and 2-benzyl... 2-Dimethylamino-1-(4-morpholinophenyl)butane-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)2,4,4-trimethylpentylphosphine oxide, and their derivatives, etc.

[0178] Examples of hydrogen-abstracting photopolymerization initiators (C2) include benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 4-(meth)acryloyloxybenzophenone, methyl 2-benzoylbenzoate, methyl benzoylformate, bis(2-phenyl-2-oxoacetic acid)oxybisethylene, 4-(1,3-acryloyl-1,4,7,10,13-pentaoxotridecyl)benzophenone, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2,4-dimethylthioxanthone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, and their derivatives.

[0179] The amount of photopolymerization initiator (C) relative to the total mass of the adhesive sheet of the present invention is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and most preferably 0.3% by mass or more. Furthermore, as an upper limit, it is preferably 10% by mass or less, preferably 8 parts by mass or less, preferably 6 parts by mass or less, preferably 5 parts by mass or less, and most preferably 4.5% by mass or less.

[0180] Furthermore, the amount of (meth)acrylic polymer (A) is preferably 0.01 to 10 parts by weight, more preferably 0.1 parts by weight or more or 7 parts by weight or less, and particularly preferably 0.5 parts by weight or more or 5 parts by weight or less.

[0181] (Silane coupling agent (D))

[0182] As a silane coupling agent (D), from the viewpoint of improving adhesion, especially the adhesion to glass materials, compounds with unsaturated groups such as vinyl, acryloyloxy, and methacryloyloxy, amino, epoxy, and hydrolyzable functional groups such as alkoxy can be listed.

[0183] Specific examples of silane coupling agents include N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-epoxypropoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. Among these, γ-epoxypropoxypropyltrimethoxysilane or γ-methacryloyloxypropyltrimethoxysilane are preferred, especially from the viewpoint of good adhesion and minimal discoloration such as yellowing.

[0184] The silane coupling agent can be used alone or in combination of two or more.

[0185] The content of the silane coupling agent is preferably 0.01 to 2% by mass relative to the total mass of the adhesive sheet of the present invention, and more preferably 0.05% by mass or more or 1% by mass or less.

[0186] (Tackifying resin)

[0187] Examples of tackifying resins include rosin-based tackifying resins, terpene-based tackifying resins, petroleum-based tackifying resins, styrene-based tackifying resins, epoxy-based tackifying resins, polyamide-based tackifying resins, elastic system tackifying resins, phenol-based tackifying resins, and ketone-based tackifying resins. Among these, rosin-based tackifying resins are particularly preferred, and rosin ester resins such as rosin ester resins, disproportionated rosin ester resins, hydrogenated rosin ester resins, and polymerized rosin ester resins are preferred.

[0188] The above-mentioned tackifying resins can be used alone or in combination of two or more.

[0189] The content of tackifying resin relative to the total mass of the adhesive sheet is preferably 1 to 40% by mass, and more preferably 3% or more by mass or 20% or less by mass.

[0190] (Other ingredients)

[0191] The resin composition forming the adhesive layer (X1) and the adhesive layer (X2) may appropriately contain various additives such as antioxidants, light stabilizers, metal passivators, anti-aging agents, hygroscopic agents, polymerization inhibitors, ultraviolet absorbers, and inorganic particles as components other than those mentioned above.

[0192] From the viewpoint of improving reliability, the resin composition forming the adhesive layer (X1) and the adhesive layer (X2) is preferably a solvent-free system that does not contain residual solvent when applying a thick material, suppresses the generation of bubbles after bonding, etc.

[0193] <Manufacturing Method>

[0194] Next, an example of a method for manufacturing an adhesive sheet with a release film according to the present invention will be described. However, the method for manufacturing an adhesive sheet with a release film according to the present invention is not limited to the following method.

[0195] Here, the case where the adhesive sheet of the present invention is composed of an adhesive layer (X1) and an adhesive layer (X2) will be described.

[0196] First, prepare the following:

[0197] A sheet winding body (Z1) comprising: an adhesive sheet with a release film having a layer structure of release film (Y1) / adhesive layer (X1) / release film (Y3) and the peel force (α1) between the release film (Y1) and the adhesive layer (X1) being greater than the peel force (α3) between the release film (Y3) and the adhesive layer (X1); and

[0198] A sheet winding body (Z2) comprising: an adhesive sheet with a release film having a layer structure of release film (Y2) / adhesive layer (X2) / release film (Y4) and the peel force (α2) between the release film (Y2) and the adhesive layer (X2) is greater than the peel force (α4) between the release film (Y4) and the adhesive layer (X2).

[0199] Next, the adhesive surface of the adhesive layer (X1) that forms a release film (Y1) / adhesive layer (X1) by unwinding the sheet winding body (Z1) and peeling off the release film (Y3) that serves as a light separator is bonded to the adhesive surface of the adhesive layer (X2) that forms a release film (Y2) / adhesive layer (X2) by unwinding the sheet winding body (Z2) and peeling off the release film (Y4) that serves as a light separator is bonded to the sheet winding body (Z2) so that a release film (Y2) / adhesive layer (X1) + adhesive layer (X2) / release film (Y2) can be produced.

[0200] The above-described manufacturing method describes the case where the adhesive sheet of the present invention is composed of an adhesive layer (X1) and an adhesive layer (X2). However, the adhesive sheet of the present invention can also be manufactured in the same way if it has three or more layers, including an adhesive layer (X1) and an adhesive layer (X2) as the surface and back layers, and an adhesive sheet (X3) as the intermediate layer. That is, in the sheet winding bodies (Z1) and (Z2), the release film serving as a light separator is peeled off. On the other hand, the release film of the adhesive sheet (X3) with the release film used to form the intermediate layer is peeled off one side at a time, and the adhesive surfaces of the adhesive sheets are bonded together. This allows the production of an adhesive sheet with a release film having a layer structure of release film (Y1) / adhesive layer (X1) + adhesive layer (X3) + adhesive layer (X2) / release film (Y2).

[0201] It should be noted that the combination of the above-mentioned sheet winding body (Z1) and the above-mentioned sheet winding body (Z2) is also referred to as the adhesive sheet winding body assembly, which can be provided in the form of the adhesive sheet winding body assembly of the present invention.

[0202] That is, the adhesive sheet winding assembly of the present invention comprises:

[0203] An adhesive sheet roll (Z1) with a layered structure having a release film (Y1) / adhesive layer (X1) / release film (Y3) and an adhesive sheet roll with a release film; and

[0204] An adhesive sheet roll (Z2) with a layered structure consisting of a release film (Y2) / adhesive layer (X2) / release film (Y4) and a release film.

[0205] The peel force (α1) between the release film (Y1) and the adhesive layer (X1) is greater than the peel force (α3) between the release film (Y3) and the adhesive layer (X1).

[0206] The peel force (α2) between the release film (Y2) and the adhesive layer (X2) is greater than the peel force (α4) between the release film (Y4) and the adhesive layer (X2).

[0207] The peel force ratio (α1 / α2) of the peel force (α1) of the release film (Y1) / adhesive layer (X1) to the peel force (α2) of the release film (Y2) / adhesive layer (X2) is 1.1 or more.

[0208] <Application>

[0209] The release films (Y1) and (Y2) of the present invention are peeled off from the adhesive sheet with the release film, and the two optical components are bonded together with the adhesive sheet of the present invention, thereby forming a laminate for an image display device (referred to as "laminate for an image display device of the present invention").

[0210] That is, the image display device laminate of the present invention is an image display device laminate having a structure in which two optical components are laminated by means of the adhesive sheet of the present invention.

[0211] Alternatively, the image display device of the present invention can be constructed using a laminate as a constituent component (referred to as "the image display device of the present invention").

[0212] That is, the image display device of the present invention is an image display device having the image display device laminate of the present invention.

[0213] Regarding the image display device laminate of the present invention and the image display device of the present invention, examples of image display devices include, for example, personal computers, televisions (TVs), mobile terminals (PDAs), mobile phones, smartphones, etc. However, it is not limited to these.

[0214] Furthermore, examples of optical components in the laminated body for the image display device of the present invention include, for example, liquid crystal display (LCD), electroluminescent display (ELD), plasma display panel (PDP), cathode ray tube display (CRT), surface electrolytic display (SED), electronic paper, transparent screen, LED diffuser plate, head-up display, and diffuser plate of TV. However, it is not limited to these.

[0215] In particular, considering the characteristics of the adhesive sheet with a release film of the present invention, namely the ability to increase the thickness of the adhesive sheet of the present invention, specifically the ability to make the thickness 300 μm or more, it is suitable for bonding large optical components with screens of 10 inches or more, especially 20 inches or more, further 30 inches or more and less than 100 inches.

[0216] <Explanation of statements, etc.>

[0217] In this invention, the term "film" is also included when it is referred to as "thin film" and the term "thin film" is also included when it is referred to as "sheet".

[0218] In this invention, when referred to as "α~β" (α and β are arbitrary numbers), unless otherwise specified, it includes the meaning of "above α and below β", and also includes the meaning of "preferably greater than α" or "preferably less than β".

[0219] In addition, when it is written as "α or above" or "α ≤" (α is any number), unless otherwise specified, it includes the meaning of "preferably greater than α". When it is written as "β or below" or "≤ β" (β is any number), unless otherwise specified, it also includes the meaning of "preferably less than β".

[0220] Example

[0221] Hereinafter, an example of an embodiment of the present invention will be described. However, the present invention is not limited to the embodiment described below.

[0222] <Ingredients>

[0223] =Main agent (main component resin)=

[0224] • A-1: ​​(Meth)acrylic acid copolymer (2-ethylhexyl acrylate (EHA) / methyl acrylate (MA) / 2-hydroxyethyl acrylate (HEA) = (mass ratio) 65 / 20 / 15, mass average molecular weight: 460,000, Tg: -24℃)

[0225] • A-2: (Meth)acrylic acid copolymer (2-ethylhexyl acrylate (EHA) / methyl acrylate (MA) / ethyl acrylate (EA) / 2-hydroxyethyl acrylate (HEA) = (mass ratio) 46 / 14 / 26 / 14, mass average molecular weight: 230,000, Tg: -9℃)

[0226] • A-3: (Meth)acrylic acid copolymer (2-ethylhexyl acrylate (EHA) / methyl acrylate (MA) / N-vinylpyrrolidone (NVP) = (mass ratio) 46 / 46 / 8, mass average molecular weight: 240,000, Tg: 0℃)

[0227] It should be noted that the mass-average molecular weight of the (meth)acrylic acid copolymer was determined using a gel permeation chromatography (GPC) analyzer (device name: HLC-8320GPC manufactured by Tosoh Corporation). Specifically, the substance obtained by dissolving 4 mg of the copolymer in 12 mL of THF was used as the test sample, and the molecular weight distribution curve was measured under the following conditions to determine the mass-average molecular weight (Mw).

[0228] • Protective column: TSKguardcolumnHXL

[0229] • Separation column: TSKgelGMHXL (4 columns)

[0230] Temperature: 40℃

[0231] Injection volume: 100μL

[0232] Polystyrene conversion

[0233] Solvent: THF

[0234] • Flow rate: 1.0 mL / min

[0235] In addition, the glass transition temperature (Tg) of the (meth)acrylic acid copolymers was measured using a rheometer (TA Instruments, "Discovery HR2"). Specifically, under the conditions of bonding fixture: Φ8mm parallel plate, strain: 0.1%, frequency: 1Hz, temperature: -50~80℃, heating rate: 5℃ / min, dynamic viscoelastic spectra were measured in the temperature range of -50℃ to 80℃. Based on the obtained data, the temperature at which the loss tangent (Tanδ) reaches its maximum value was read, and Tg was calculated from this.

[0236] =Materials other than the main agent (main component resin)=

[0237] • B-1: PDP-400N (manufactured by Nippon Oil Company): Polypropylene glycol dimethacrylate

[0238] • C-1: EsacureTZT (manufactured by IGM): A mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone.

[0239] •C-1: MBP (manufactured by Shin-Mitsubishi); 4-Methacryloxybenzophenone

[0240] • D-1: KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.): 3-Epoxypropoxypropyltrimethoxysilane

[0241] =Demolding film=

[0242] • Lightweight release film: Release film I: MHE75: (PET film manufactured by Mitsubishi Chemical Corporation, 75μm thick, with silicone release layer)

[0243] • Heavy-duty release film: Release film II: MRQ100: (Made by Mitsubishi Chemical Corporation, 100μm thick, PET film with silicone release layer)

[0244] • Heavy-duty release film: Release film III: MRV100(V03): (Made by Mitsubishi Chemical Corporation, 100μm thick, PET film with silicone release layer)

[0245] <Adhesive sheet 1 with release film>

[0246] Weigh the above-mentioned raw materials in the amounts shown in Table 1 below and mix them to prepare an adhesive composition. Spread the adhesive composition into a sheet on release film II.

[0247] Next, release film I is laminated onto the sheet-like adhesive composition. The cumulative light intensity at a wavelength of 365 nm is 3000 mJ / cm². 2The method involves using a high-pressure mercury lamp to irradiate the release films I and II with ultraviolet light (1500 mJ / cm² per side) through both sides of the release films I and II. 2 The adhesive composition is cured to obtain an adhesive sheet 1 with a release film, which is composed of a layer structure of release film I / adhesive sheet (thickness 200 μm) / release film II.

[0248] <Adhesive sheets 2~11 with release film>

[0249] As shown in Table 1, adhesive sheets 2 to 11 with release films were obtained in the same manner as in Example 1, except that the types and amounts of raw materials, the type of release film, the amount of ultraviolet irradiation, and the thickness of the adhesive sheet were changed when preparing the adhesive composition.

[0250] [Storage modulus (G') and glass transition temperature (Tg)]

[0251] Peel off the release film from adhesive sheets 1 to 11 with the release film, stack the adhesive sheets to a thickness of 0.6 to 0.8 mm, and punch them into a circle with a diameter of 8 mm, which is then used as the test sample.

[0252] Using a rheometer (manufactured by TA Instruments, "DiscoveryHR2"), the dynamic viscoelastic spectrum was measured in the temperature range of -50℃ to 200℃ under the following conditions: bonding fixture: Φ8mm parallel plate, strain: 0.1%, frequency: 1Hz, temperature: -50~200℃, heating rate: 5℃ / min. The storage modulus (G') of the bonded sheet at temperatures of -20℃, 0℃, 25℃, 40℃, 60℃, and 80℃ was calculated from the obtained data.

[0253] In addition, the measured value of Tg for the adhesive sheet is obtained by reading the temperature at which Tanδ reaches its maximum value, i.e., the peak temperature.

[0254] [Gel fraction]

[0255] Peel off one release sheet from adhesive sheets 1-11 with a release film, attach the adhesive sheet side to a 50mm×100mm SUS mesh (200 mesh), peel off another release sheet, fold it back from the center relative to the length of the SUS mesh to wrap the sample, and then determine the gel fraction (mass %) based on the mass change after immersion at 23°C for 24 hours in a sealed container containing 250g of ethyl acetate.

[0256] [Peeling force]

[0257] For adhesive sheets 1-11 with release films, one release film was peeled off each time, and a 100μm PET film (manufactured by Mitsubishi Chemical Corporation, "DIAFOIL T100") was laminated as a backing film. After cutting the film to 150mm in length and 10mm in width, the remaining release film was peeled off, and the exposed adhesive surface was rolled and pressed onto soda-lime glass to form a laminated product. The laminated products were then subjected to autoclave treatment (60°C, 0.2MPa gauge pressure, 20 minutes) for final bonding, and then cured at 23°C and 50%RH for 12 hours to prepare samples for adhesive strength testing.

[0258] For the above samples, the peel force (N / cm) was measured when peeling was performed at a peel angle of 180° and a peel speed of 60 mm / min in an environment of 23°C and 50%RH.

[0259] [Optical Properties]

[0260] For adhesive sheets 1 to 11 with release films, peel off one release film, attach the adhesive sheet side to soda-lime glass (0.6 mm thick), peel off the other release film, attach it to soda-lime glass, and make a test piece with a structure of "soda-lime glass / adhesive layer / soda-lime glass".

[0261] The total transmittance and haze were measured using the obtained test pieces.

[0262] It should be noted that the total transmittance was measured using a HAZE MATER NDH2000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.). It should also be noted that the main unit was designed according to JIS K7361-1.

[0263] Haze was determined by measuring the diffusion transmittance and total transmittance using a HAZE MATER NDH2000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.). The obtained values ​​of diffusion transmittance and total transmittance were substituted into Equation 4 below to calculate the haze.

[0264] [Equation 4] Haze (%) = (Diffusion transmittance / Total transmittance) × 100

[0265] For the adhesive sheets 1 to 11 with the release film peeled off on both sides, the refractive index was measured according to JIS K7124 using an Atago Abbe refractometer with sodium D line (589nm) as the light source.

[0266] [Determination of release film peel strength]

[0267] After cutting adhesive sheets 1-11 with release film into lengths of 200mm and widths of 50mm, the heavy release film (heavy separator) side is pressed onto the glass using a double-sided adhesive tape roller. The peel force (N / cm) when peeling the light release film (light separator) at a peel angle of 180° and a peel speed of 300mm / min in an environment of 23°C and 50%RH is taken as the light separator peel force. Similarly, after cutting into lengths of 200mm and widths of 50mm, the light separator is peeled off, and the exposed adhesive surface is pressed onto the glass using a roller. The peel force (N / cm) when peeling the heavy separator at a peel angle of 180° and a peel speed of 300mm / min in an environment of 23°C and 50%RH is taken as the heavy separator peel force. The ratio of heavy separator peel force to light separator peel force is taken as the heavy-light separator peel force ratio.

[0268] [Table 1]

[0269]

[0270] <Examples 1-6>

[0271] From the adhesive sheet with release film shown in Table 2 ((Y1) / (X1) / (Y3)), the release film (Y3) serving as a light separator is peeled off to form a release film (Y1) / adhesive layer (X1). On the other hand, from the adhesive sheet with release film (Y2) / (X2) / (Y4)), the release film (Y4) serving as a light separator is peeled off to form a release film (Y2) / adhesive layer (X2). The adhesive surface of the adhesive layer (X1) is bonded to the adhesive surface of the adhesive layer (X2) to produce an adhesive sheet (sample) with release film having a layer structure of release film (Y1) / adhesive layer (X1) + adhesive layer (X2) / release film (Y2).

[0272] <Example 7>

[0273] From the adhesive sheet with release film shown in Table 2 ((Y1) / (X1) / (Y3)), the release film (Y3) serving as a light separator is peeled off to form a release film (Y1) / adhesive layer (X1). On the other hand, the release film serving as a light separator of the adhesive sheet with release film constituting the intermediate layer is peeled off to form a release film / adhesive sheet. The adhesive surface of the adhesive layer (X1) is attached to the adhesive surface of the adhesive sheet, thereby forming an adhesive sheet with release film having a layer structure of release film (Y1) / adhesive layer (X1) / intermediate layer / release film of intermediate layer.

[0274] Next, a release film (Y4) serving as a light separator is peeled off from the adhesive sheet ((Y2) / (X2) / (Y4)) with a release film to form a release film (Y2) / adhesive layer (X2). The release film serving as a heavy separator of the adhesive sheet with a release film constituting the intermediate layer is peeled off, and the adhesive surface of the adhesive layer (X2) is attached to the adhesive surface of the adhesive sheet to produce an adhesive sheet (sample) with a layer structure of release film (Y1) / adhesive layer (X1) + intermediate layer adhesive layer + adhesive layer (X2) / release film (Y2).

[0275] <Comparative Examples 1 to 4>

[0276] The adhesive sheets with release films shown in Table 2 were used as evaluation samples.

[0277] <Evaluation>

[0278] The adhesive sheets (samples) with release films prepared or fabricated in Examples 1-7 and Comparative Examples 1-4 are evaluated as follows.

[0279] [Cascading Interfaces]

[0280] The adhesive sheets with release films prepared or fabricated in the examples and comparative examples were cut with a feather knife cooled by immersion in liquid nitrogen, and their cross-sections were observed using an electron microscope (device: Nicon LV100ND, image: transmission image, magnification: 20x). The number of observable layer interfaces was recorded.

[0281] [Determination of release film peel strength]

[0282] After cutting the adhesive sheet with release film prepared in the examples and comparative examples into a length of 200 mm and a width of 50 mm, the heavy-duty isolation part side is pressed onto the glass using a double-sided adhesive tape roller.

[0283] The peel force (N / cm) for peeling the light separator at a peel angle of 180° and a peel speed of 300 mm / min under conditions of 23°C and 50%RH is defined as the light separator peel force. Similarly, after cutting to a length of 200 mm and a width of 50 mm, the light separator is peeled off, and the exposed adhesive surface is rolled and pressed onto the glass. The peel force (N / cm) for peeling the heavy separator at a peel angle of 180° and a peel speed of 300 mm / min under conditions of 23°C and 50%RH is defined as the heavy separator peel force / light separator peel force is defined as the peel force ratio.

[0284] [Evaluation of preservation stability]

[0285] Prepare a paper tube with an inner diameter of 10 inches (width 1250mm). The adhesive sheet with release film prepared or made in the examples and comparative examples is wound with the light separator roll on the outside and the heavy separator roll on the inside, with a width of 1000mm for 200m. Then, a 30-day storage test is carried out at 23℃ and 50%RH. The roll sample after the test is unwound and the appearance is checked.

[0286] The condition that cannot be wound onto the roller and results in the release film peeling is judged as "×× (bad)". The condition that can be wound onto the roller but results in the release film peeling upon unwinding after a 30-day storage test is judged as "× (usual)". The condition that also has a good appearance after the storage test is judged as "○ (good)".

[0287] [Treatment Evaluation]

[0288] Ten samples were prepared by cutting the adhesive sheets with release film, which were made or prepared in the examples and comparative examples, into 210×300 mm pieces using a Thomson die-cutting machine. The workability of these light spacers was evaluated when peeled off by hand along the diagonal direction.

[0289] If one or more of the 10 sheets have defects such as the light separator not being able to be peeled off properly or the side interface of the heavy separator peeling off, it is judged as "×". If all 10 sheets can be peeled off without defects, it is judged as "○".

[0290] [Contour following: Evaluation of fit to appearance]

[0291] For the adhesive sheets with release films prepared or fabricated in the examples and comparative examples, they were cut to 52×80mm using a Thomson die cutter while the release films were stacked. The adhesive surface exposed by peeling off the release film on one side was pressed and bonded to the printed surface of a soda-lime glass (82mm×54mm×0.5mm) with a thickness of 50μm printed on the periphery by a vacuum press, with the four sides of the adhesive sheet covering the printing height difference. The press was performed at a temperature of 23°C and a pressing pressure of 0.3MPa.

[0292] Next, the remaining release film is peeled off, and the PET film (DIAFOIL T100-200, 82mm×54mm×0.2mm thickness) is laminated using a 2kg hand roller. Then, it is subjected to autoclave treatment (60℃, gauge pressure 0.2MPa, 20 minutes) for final lamination to produce a glass / double-sided adhesive sheet / PET film laminate with height difference.

[0293] The unevenness of the PET film near the printing height difference was observed by projecting the fabricated laminate onto a projector.

[0294] The projector and screen were positioned 2m apart. The stacked structure was then positioned parallel to the screen, 40cm away from it, and the appearance of the projected image was observed.

[0295] The case where there is a thick, dark shadow near the printing height difference and poor embossing is judged as "× (usual)", the case where there is a slightly lighter shadow near the printing height difference and good embossing is judged as "○ (good)", and the case where there is no shadow near the printing height difference and very good embossing is judged as "◎ (very good)".

[0296] [Table 2]

[0297]

[0298] (Inspection)

[0299] Based on the above embodiments, comparative examples, and the test results conducted by the inventors to date, it is believed that if the thickness of the adhesive sheet of the present invention is 300 μm or more, it can achieve good height difference tracking for large height differences.

[0300] It has been confirmed that when the thickness of both adhesive layer (X1) and adhesive layer (X2) is 100 μm or more, and the ratio (x2 / x1) of the thickness of adhesive layer (X2) to the thickness of adhesive layer (X1) is 1 to 3, it is a bonding form with fewer interlayer interfaces (fewer adhesive layers), which can enable good performance in various aspects.

[0301] Furthermore, it has been confirmed that if two or more adhesive sheets with a thickness of 100 μm or more are made as described above, and these adhesive sheets are bonded together to make the adhesive sheet of the present invention with an interface, a winding body suitable for storage and transportation can be made, thus ensuring good storage stability.

[0302] Furthermore, it was confirmed that by making the peel force (α1) between the release film (Y1) and the adhesive layer (X1) greater than the peel force (α2) between the release film (Y2) and the adhesive layer (X2), the release films on both sides can be easily peeled off.

Claims

1. An adhesive sheet having an adhesive layer X1 and an adhesive layer X2, Both adhesive layer X1 and adhesive layer X2 contain adhesive components derived from (meth)acrylic polymer A. The total thickness of the adhesive sheet is 300 μm or more, the thickness of adhesive layer X1 and adhesive layer X2 is 100 μm or more, and the ratio of the thickness x2 of adhesive layer X2 to the thickness x1 of adhesive layer X1, i.e., x2 / x1, is 1 to 3.

2. The adhesive sheet according to claim 1, wherein When the cross-section of the adhesive sheet was observed using an electron microscope, the interface between adhesive layer X1 and adhesive layer X2 was observed.

3. The adhesive sheet according to claim 1, wherein The energy storage modulus G' of both adhesive layer X1 and adhesive layer X2 at a temperature of 25°C is above 1 kPa and below 1000 kPa.

4. The adhesive sheet according to claim 1, wherein The energy storage modulus G' of both adhesive layer X1 and adhesive layer X2 at a temperature of 60°C is above 0.1 kPa and below 200 kPa.

5. The adhesive sheet according to claim 1, wherein The glass transition temperatures (Tg) of both adhesive layer X1 and adhesive layer X2 are above -50°C and below 5°C.

6. A laminate for an image display device, comprising a structure in which two optical components are laminated by means of an adhesive sheet according to any one of claims 1 to 5, wherein the size of the optical components is 10 inches or more and 100 inches or less.

7. An adhesive sheet winding assembly, comprising: An adhesive sheet roll Z1 with a release film having a layered structure of release film Y1 / adhesive layer X1 / release film Y3; and Z2 is an adhesive sheet roll with a release film having a layered structure of release film Y2 / adhesive layer X2 / release film Y4. The peel force α1 between the release film Y1 and the adhesive layer X1 is greater than the peel force α3 between the release film Y3 and the adhesive layer X1. The peel force α2 between the release film Y2 and the adhesive layer X2 is greater than the peel force α4 between the release film Y4 and the adhesive layer X2. The peel force ratio α1 of the release film Y1 / adhesive layer X1 to the peel force α2 of the release film Y2 / adhesive layer X2, i.e., α1 / α2, is 1.1 or more.

8. The adhesive sheet roll body according to claim 7, wherein Both adhesive layer X1 and adhesive layer X2 contain adhesive components derived from (meth)acrylic polymer A.

9. The adhesive sheet winding assembly according to claim 7, wherein, The thickness of both adhesive layer X1 and adhesive layer X2 is 100 μm or more.

10. The adhesive sheet winding assembly according to claim 7, wherein, The energy storage modulus G' of both adhesive layer X1 and adhesive layer X2 at a temperature of 25°C is above 1 kPa and below 1000 kPa.

11. The adhesive sheet winding assembly according to claim 7, wherein, The energy storage modulus G' of both adhesive layer X1 and adhesive layer X2 at a temperature of 60°C is above 0.1 kPa and below 200 kPa.

12. The adhesive sheet winding assembly according to claim 7, wherein, The glass transition temperatures (Tg) of both adhesive layer X1 and adhesive layer X2 are above -50°C and below 5°C.

13. A method for manufacturing an adhesive sheet with a release film, wherein, Prepare separately: A sheet winding body Z1, comprising: an adhesive sheet with a release film having a layer structure of release film Y1 / adhesive layer X1 / release film Y3, wherein the peel force α1 between release film Y1 and adhesive layer X1 is greater than the peel force α3 between release film Y3 and adhesive layer X1; and A sheet winding body Z2 comprises: an adhesive sheet with a release film having a layer structure of release film Y2 / adhesive layer X2 / release film Y4, wherein the peel force α2 between release film Y2 and adhesive layer X2 is greater than the peel force α4 between release film Y4 and adhesive layer X2. The adhesive surface of the adhesive layer X1, which forms a release film Y1 / adhesive layer X1 by unwinding the sheet winding body Z1 and peeling off the release film Y3, is bonded with the adhesive surface of the adhesive layer X2, which forms a release film Y2 / adhesive layer X2 by unwinding the sheet winding body Z2 and peeling off the release film Y4, thereby producing an adhesive sheet with a release film having a layer structure of release film Y1 / adhesive layer X1 / adhesive layer X2 / release film Y2.

14. The method for manufacturing an adhesive sheet with a release film according to claim 13, wherein, The peel force ratio α1 of the release film Y1 / adhesive layer X1 to the peel force α2 of the release film Y2 / adhesive layer X2, i.e., α1 / α2, is 1.1 or more.

Images