Adhesive sheet and method for manufacturing the same

Abstract

The present invention relates to an adhesive sheet and a manufacturing method therefor, the adhesive sheet comprising a laminate formed from a base material and an adhesive layer. The base material is formed by irradiating an energy line onto a resin film comprising (A) a polymer and (B) a hydrogen-extraction type photoinitiator. The component (A) is a polymer from which hydrogen can be extracted by the component (B). The adhesive layer is formed by irradiating an energy line onto an energy line cross-linkable adhesive composition layer formed from an energy line cross-linkable adhesive composition. The laminate formed from the base material and the adhesive layer is formed by irradiating the energy line onto a laminate formed from the resin film and the energy line cross-linkable adhesive composition layer.

Description

Technical Field

[0001] The present invention relates to an adhesive sheet and a method for producing the same.

Background Art

[0002] Adhesive sheets are used in a wide range of industrial fields, for example, for label applications for displaying various information, for fixing or temporarily fixing parts in fields such as OA equipment, home appliances, automobiles, and construction, and for masking applications. Hot melt adhesives are widely used as adhesives for adhesive sheets. Since hot melt adhesives can be applied to a substrate or the like by heating and melting without using a solvent, there is an advantage that the environmental load during the production of the adhesive sheet can be reduced. As hot melt adhesives, for example, synthetic rubber-based hot melt adhesives are widely known. In response to the increasing need for environmental load reduction, in recent years, the development of acrylic-based hot melt adhesives and the like has also been promoted. For example, Patent Document 1 discloses a radiation-curable hot melt adhesive characterized by containing 100 parts by weight of an acrylic polymer having a radiation-reactive group, 3 to 20 parts by weight of an acrylic monomer, and 0.002 to 0.2 parts by weight of a polymerization inhibitor having a specific structure.

Prior Art Documents

Patent Documents

[0003] [[ID=二十七]] [[ID=二十八]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=四十]] Generally, adhesive sheets are formed by laminating a substrate and an adhesive layer. However, if the adhesion between the substrate and the adhesive layer is insufficient, when removing an adhesive sheet that has been attached to an object, the substrate and adhesive layer may separate at the interface, leaving residue on the object. This problem is particularly likely to occur when using low-polarity substrates such as polyvinyl chloride or polyolefin. Such residue of adhesive on the substrate is undesirable because it will contaminate the substrate.

[0005] The present invention has been made in view of the above problems, and aims to provide an adhesive sheet that has excellent adhesion to a substrate and can be peeled off without contaminating the adherend. [Means for solving the problem]

[0006] The inventors of the present invention have found that an adhesive sheet comprising a laminate of a specific substrate and a specific adhesive layer can solve the aforementioned problems, and have completed the present invention. In other words, the present invention relates to the following [1] to

[11] . [1] An adhesive sheet comprising a laminate of a substrate and an adhesive layer, The substrate is formed by irradiating a resin film containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator with energy rays, wherein component (A) is a polymer capable of hydrogen abstraction by component (B), The adhesive layer is formed by irradiating an energy ray crosslinkable adhesive composition layer, which is made of an energy ray crosslinkable adhesive composition, with energy rays. The laminate of the substrate and the adhesive layer is an adhesive sheet formed by irradiating the laminate of the resin film and the energy-ray crosslinkable adhesive composition layer with energy rays. [2] The adhesive sheet according to [1], wherein component (A) is at least one selected from the group consisting of polyvinyl chloride resin, polyolefin, acrylic resin, and styrene resin. [3] The adhesive sheet according to [1] or [2], wherein the content of component (B) in the resin film is 10 parts by mass or less per 100 parts by mass of component (A). [4] The adhesive sheet according to any one of [1] to [3] above, wherein the content of component (A) in the resin film is 50% by mass or more of the total mass of the components constituting the resin film. [5] The adhesive sheet according to any one of [1] to [4], wherein the energy-ray crosslinkable adhesive composition is an adhesive composition (I) containing (C) an acrylic polymer having energy-ray crosslinkability, or an adhesive composition (II) containing (D) an acrylic polymer other than component (C) and (B) a hydrogen abstraction type photoinitiator. [6] Component (C) in the adhesive composition (I) is an acrylic polymer having an energy-reactive group that reacts upon energy ray irradiation and contributes to the formation of a crosslinked structure, The adhesive sheet according to [5], wherein component (C1) is an acrylic polymer having a benzophenone structure in its side chain. [7] The adhesive sheet according to [5] or [6], wherein the content of component (C) is 50 to 100% by mass of the total amount of the adhesive composition (I). [8] The adhesive sheet according to [5], wherein the content of component (D) is 50% by mass or more of the total amount of the adhesive composition (II) (100% by mass). [9] A method for manufacturing an adhesive sheet according to any one of [1] to [8] above, comprising the following steps 1 to 3 in this order. Step 1: A step of forming a resin film containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator. Step 2: A step of laminating the resin film obtained in Step 1 with an energy ray crosslinkable adhesive composition layer made of an energy ray crosslinkable adhesive composition to form a laminate of the resin film and the energy ray crosslinkable adhesive composition layer. Step 3: A step of irradiating the laminate of the resin film obtained in Step 2 and the energy-ray crosslinkable adhesive composition layer made of the energy-ray crosslinkable adhesive composition with energy rays to form a laminate of the substrate and the adhesive layer.

[10] An adhesive sheet comprising a laminate of a resin film and an energy ray crosslinkable adhesive composition layer, The resin film is an adhesive sheet containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator, wherein component (A) is a polymer capable of hydrogen abstraction by component (B).

[11] A resin film comprising (A) a polymer and (B) a hydrogen abstraction type photoinitiator, wherein component (A) is a polymer capable of hydrogen abstraction by component (B). [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an adhesive sheet that has excellent adhesion to the substrate and can be peeled off without contaminating the adherend. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing an example of the structure of the adhesive sheet of the present invention. [Figure 2] This is a schematic cross-sectional view showing another example of the structure of the adhesive sheet of the present invention. [Figure 3] This is a schematic cross-sectional view showing another example of the structure of the adhesive sheet of the present invention. [Modes for carrying out the invention]

[0009] In this specification, for preferred numerical ranges (such as ranges of content etc.), the lower limit value and the upper limit value described step by step can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60", it is also possible to combine the "preferred lower limit value (10)" and the "more preferred upper limit value (60)" to obtain "10 to 60". Also, for example, the same applies to the description method of "preferably 10 or more, more preferably 30 or more, and preferably 90 or less, more preferably 60 or less".

[0010] In this specification, the "energy ray" means a thing having energy quanta among electromagnetic waves or charged particle beams, and examples thereof include ultraviolet rays, radiation, electron beams, etc. Ultraviolet rays can be irradiated, for example, by using an electrodeless lamp, a high-pressure mercury lamp, a metal halide lamp, a UV-LED, etc. as an ultraviolet ray source. Electron beams can be irradiated with those generated by an electron beam accelerator, etc. Among the above-mentioned things, ultraviolet rays are preferred as the energy ray in one aspect of the present invention. In this specification, the "energy ray crosslinkability" means the property of forming a crosslinked structure by irradiating an energy ray. Also, in this specification, the "solid content" refers to the components among the components contained in the target composition excluding diluting solvents such as water and organic solvents. Also, in this specification, "(meth)acryl" is used as a term meaning one or both of "acryl" or "methacryl". Similarly, "(meth)acrylate" is used as a term meaning one or both of "acrylate" or "methacrylate". Similarly, "(meth)acryloyl" is used as a term meaning one or both of "acryloyl" or "methacryloyl". Also, in this specification, the "weight average molecular weight (Mw)" is a value in terms of standard polystyrene measured by the gel permeation chromatography (GPC) method, and specifically, it is a value measured based on the method described in the examples. Further, the mechanism of action described in this specification is a speculation and does not limit the mechanism by which the effects of the present invention are achieved.

[0011] [Adhesive sheet] A first adhesive sheet which is one aspect of the present invention is an adhesive sheet including a laminate of a resin film and an energy ray crosslinkable adhesive composition layer made of an energy ray crosslinkable adhesive composition, wherein the resin film contains (A) a polymer and (B) a hydrogen abstraction type photoinitiator, and component (A) is a polymer capable of hydrogen abstraction by component (B). Further, a second adhesive sheet which is one aspect of the present invention is an adhesive sheet including a laminate of a base material and an adhesive layer, wherein the base material is formed by irradiating an energy ray to a resin film containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator, component (A) is a polymer capable of hydrogen abstraction by component (B), the adhesive layer is formed by irradiating an energy ray to an energy ray crosslinkable adhesive composition layer made of an energy ray crosslinkable adhesive composition, and the laminate of the base material and the adhesive layer is formed by irradiating the energy ray to the laminate of the resin film and the energy ray crosslinkable adhesive composition layer. In the following description, the "energy ray crosslinkable adhesive composition" is also simply referred to as the "adhesive composition". Further, the "energy ray crosslinkable adhesive composition layer made of an energy ray crosslinkable adhesive composition" is also simply referred to as the "adhesive composition layer". Also, when simply referred to as an "adhesive sheet", it means both the first adhesive sheet and the second adhesive sheet.

[0012] Next, an example of the configuration of an adhesive sheet which is one aspect of the present invention will be described using the drawings, but it is not limited to the following examples.

[0013] In Fig. 1(a), as an example of the first adhesive sheet, an adhesive sheet 10a having a release liner 3 on one surface side of an adhesive composition layer 1 and a resin film 2 on the other surface side of the adhesive composition layer 1 is shown. Furthermore, Figure 1(b) shows an example of a second adhesive sheet, an adhesive sheet 10b having a release liner 3 on one side of the adhesive layer 4 and a base material 5 on the other side of the adhesive layer 4. As described above, the laminate of the adhesive layer 4 of the second adhesive sheet and the substrate 5 is formed by irradiating the laminate of the adhesive composition layer 1 of the first adhesive sheet and the resin film 2 with the energy rays. The adhesive sheets 10a and 10b are suitable for applications such as peeling off the release liner 3 and then attaching the exposed adhesive composition layer 1 or adhesive layer 4 to an object. Examples of such applications include label applications. Furthermore, if the adhesive sheet to be attached to the adherend is the first adhesive sheet, after attaching it to the adherend, energy rays may be irradiated onto the laminate of the resin film 2 and the adhesive composition layer 1 to form a laminate of the base material 5 and the adhesive layer 4 included in the second adhesive sheet.

[0014] Figure 2(a) shows a double-sided adhesive sheet 20a as another example of the first adhesive sheet, which has adhesive composition layers 1 on both sides of a resin film 2, with a release liner 3a on the side of one adhesive composition layer 1 opposite to the resin film 2, and a release liner 3b on the side of the other adhesive composition layer 1 opposite to the resin film 2. In Figure 2(a), the multiple adhesive composition layers 1 may be composed of the same components or of different components. Furthermore, Figure 2(b) shows a double-sided adhesive sheet 20b as another example of a second adhesive sheet, which has adhesive layers 4 on both sides of a base material 5, with a release liner 3a on the side of one adhesive layer 4 opposite to the base material 5, and a release liner 3b on the side of the other adhesive layer 4 opposite to the base material 5. In Figure 2(b), the multiple adhesive layers 4 may be composed of the same components or of different components.

[0015] Figure 3(a) shows a double-sided adhesive sheet 30a as another example of the first adhesive sheet, which has adhesive composition layers 1 on both sides of a laminate composed of three layers: a resin film 2, a support 6, and another resin film 2, with a release liner 3a on the side of one adhesive composition layer 1 opposite to the resin film 2, and a release liner 3b on the side of the other adhesive composition layer 1 opposite to the resin film 2. Furthermore, the support 6 in Figure 3(a) may be a resin film 2. In Figure 3(a), the multiple adhesive composition layers 1 may be composed of the same components or of different components. In Figure 3(a), the multiple resin films 2 may each be layers composed of the same component or layers composed of different components. Figure 3(b) also shows a double-sided adhesive sheet 30b as another example of a second adhesive sheet, which has adhesive layers 4 on both sides of a laminate composed of three layers: a base material 5, a support 6, and another base material 5, with a release liner 3a on the side of one adhesive layer 4 opposite to the base material 5, and a release liner 3b on the side of the other adhesive layer 4 opposite to the base material 5. Furthermore, the support 6 in Figure 3(b) may be the base material 5. In Figure 3(b), the multiple adhesives 4 may each be layers composed of the same component or layers composed of different components. In Figure 3(b), the multiple substrates 5 may each be layers composed of the same component or layers composed of different components. Next, we will describe in more detail each layer constituting the adhesive sheet, which is one aspect of the present invention, and each component contained in each layer.

[0016] <Base material> The substrate is formed by irradiating a resin film containing (A) a polymer (hereinafter also referred to as "component (A)") and (B) a hydrogen abstraction type photoinitiator (hereinafter also referred to as "component (B)") with energy rays. In other words, as described above, it is formed by irradiating the resin film of the first adhesive sheet with energy rays.

[0017] (Resin film) A resin film according to one aspect of the present invention contains (A) a polymer and (B) a hydrogen abstraction type photoinitiator, wherein component (A) is a polymer from which hydrogen can be abstracted by component (B). This resin film can be used as the resin film of the first adhesive sheet, and as described above, by irradiating the laminate of the resin film and the energy ray crosslinkable adhesive composition layer with energy rays, a laminate of the substrate and the adhesive layer of the second adhesive sheet can be formed. In other words, a resin film according to one aspect of the present invention can be used as a resin film for forming the substrate of the second adhesive sheet.

[0018] [(A) Polymer] The polymer (A) is a polymer from which hydrogen can be abstracted by a hydrogen abstraction type photoinitiator (B). Component (A) may be used alone or in combination of two or more types. Component (A) is a polymer from which hydrogen can be abstracted by component (B), and is not particularly limited as long as the effects of the present invention are achieved, but preferably at least one selected from the group consisting of polyvinyl chloride resins, polyolefins, acrylic resins, and styrene resins. On the other hand, examples of polymers in which hydrogen abstraction by component (B) is not possible, i.e., polymers that are not component (A), include polyethylene terephthalate.

[0019] Examples of the polyolefin include homopolymers or copolymers of linear, branched, or cyclic olefin monomers such as ethylene; α-olefins such as propylene, 1-butene, 4-methyl-1-pentene, 1-pentene, 1-hexene, and 1-octene; and cycloolefins. Examples include polypropylene and polyethylene. Also, copolymers mainly composed of olefin monomers such as ethylene-vinyl acetate copolymer (EVA), ethylene-(meth)acrylic acid copolymer, and ethylene-(meth)acrylate copolymer are also included. Here, "main monomer" refers to the monomer that is present in the largest amount among all monomer components constituting the resulting copolymer. Examples of the acrylic resin include homopolymers or copolymers of acrylic monomers such as ethylenically unsaturated carboxylic acids like (meth)acrylic acid, alkyl (meth)acrylates like methyl (meth)acrylate, and polymethyl methacrylate (PMMA). Also, copolymers with acrylic monomers as the main monomer, such as ethylene-(meth)acrylic acid copolymers and ethylene-(meth)acrylate copolymers, are also included. Examples of the styrene-based resin include polystyrene.

[0020] Component (A) more preferably contains at least a polyvinyl chloride resin, and even more preferably is a polyvinyl chloride resin. Polyvinyl chloride resins are polymers that have repeating units derived from vinyl chloride. The polyvinyl chloride resin may be a homopolymer of vinyl chloride (polyvinyl chloride), or a copolymer of vinyl chloride and a monomer copolymerizable with said vinyl chloride. In one embodiment of the present invention, polyvinyl chloride is preferred as the polyvinyl chloride resin. Examples of the polyvinyl chloride-based resin copolymer include ethylene-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer, and vinyl chloride-halogenated olefin copolymer, which are mainly composed of vinyl chloride. In the vinyl chloride copolymer, the amount of repeating units derived from vinyl chloride is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more of the total repeating units.

[0021] Furthermore, the average degree of polymerization of the polyvinyl chloride resin is not particularly limited as long as the effects of the present invention are achieved, but is preferably 500 to 5,000, more preferably 800 to 2,500, and even more preferably 1,000 to 2,000.

[0022] Furthermore, polyvinyl chloride resins may be used individually or in combination of two or more types. In addition, polyvinyl chloride resins can be used in combination with other resins. Preferably, the other resins have excellent compatibility with polyvinyl chloride resins. When polyvinyl chloride resin is used in combination with other resins, the amount of the other resin is preferably 1 to 50 parts by mass, more preferably 3 to 30 parts by mass, and even more preferably 5 to 10 parts by mass, per 100 parts by mass of the polyvinyl chloride resin. Furthermore, as will be described later, when using polyvinyl chloride resin, it is preferable to use a plasticizer from the viewpoint of improving the flexibility of the base material.

[0023] The content of component (A) in the resin film is not particularly limited as long as the effects of the present invention are achieved, but for example, it is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less, out of 100% by mass of the total components constituting the resin film. Furthermore, in one embodiment of the present invention, when the component (A) is a resin film using a polyvinyl chloride resin, the content of component (A) in the resin film is not particularly limited as long as the effects of the present invention are achieved, but for example, it is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, out of 100% by mass of the total components constituting the resin film.

[0024] [(B) Hydrogen abstraction type photoinitiator] The hydrogen abstraction type photoinitiator (B) has the function of generating radicals by reacting with a hydrogen donor upon irradiation with energy rays. Component (B) abstracts hydrogens bonded to carbon atoms in the main chain skeleton of component (A), generating radicals in component (A) that serve as reaction initiation sites. This causes crosslinking reactions between components (A) and between component (A) and the polymer components in the adhesive composition layer. It is believed that this direct crosslinking reaction between component (A) and the polymer components in the adhesive composition layer improves adhesion at the interface between the substrate and the adhesive layer in the second adhesive sheet formed by irradiation with energy rays. As a result, the second adhesive sheet exhibits excellent substrate adhesion and can be peeled off without contaminating the adherend.

[0025] Examples of component (B) include aromatic ketones such as acetophenone, benzophenone, P,P'-dimethoxybenzophenone, 4-methylbenzophenone, P,P'-dichlorobenzophenone, P,P'-dimethylbenzophenone, and acetonaphthone. Other examples include aromatic aldehydes such as terephthalaldehyde and quinone-based aromatic compounds such as methylanthraquinone. Among these, it is preferable to use a compound containing benzophenone from the viewpoint of ease of radical generation. Component (B) may be used alone or in combination of two or more types.

[0026] The content of component (B) in the resin film is not particularly limited as long as the effects of the present invention are achieved, but from the viewpoint of obtaining an adhesive sheet that can be peeled off without further contamination of the adherend, for example, it is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of component (A) constituting the resin film, and from the viewpoint of the flexibility of the substrate, it is preferably 10 parts by mass or less, more preferably 9 parts by mass or less, and even more preferably 8 parts by mass or less.

[0027] [Other ingredients] The resin film may contain other components besides components (A) and (B) described above, as necessary, insofar as the effects of the present invention are achieved. Other components include, for example, substrate additives such as plasticizers, known fillers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, slip agents, antiblocking agents, colorants, and catalysts. These substrate additives may be used individually or in combination of two or more types.

[0028] {plasticizer} In one embodiment of the present invention, when the resin film contains a polyvinyl chloride resin as component (A), it is preferable that the resin film further contains a plasticizer as another component, from the viewpoint of improving the flexibility of the substrate. As a plasticizer, any plasticizer that is compatible with polyvinyl chloride resin can be used without particular limitations. Examples of plasticizers include phthalate-based plasticizers such as dibutyl phthalate (DBP), dioctyl phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and diundecyl phthalate (DUP); adipic acid-based plasticizers such as dibutyl adipate; phosphate-based plasticizers such as tributyl phosphate, tricresyl phosphate, and triphenyl phosphate; trimellitic acid-based plasticizers such as tributyl trimellitic acid and trioctyl trimellitic acid; various polyester-based plasticizers such as adipic acid-based polyesters; and citrate esters such as acetyl tributyl citrate and acetyl trioctyl citrate. These plasticizers may be used individually or in combination of two or more types.

[0029] If the resin film contains a polyvinyl chloride resin as component (A) and further contains the plasticizer, the content of the plasticizer is not particularly limited as long as the effects of the present invention are achieved, but for example, it is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less, per 100 parts by mass of the polyvinyl chloride resin constituting the resin film.

[0030] Furthermore, from the viewpoint of making the effects of the present invention easier to achieve, the total content of component (A) and component (B) in the resin film is preferably 60 to 100% by mass, more preferably 65 to 100% by mass, even more preferably 70 to 100% by mass, and even more preferably 75 to 100% by mass, of the total amount of components constituting the resin film. Furthermore, in one embodiment of the present invention, if the resin film contains a polyvinyl chloride resin as component (A) and further contains the plasticizer, the total content of component (A) and component (B) in the resin film is preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, out of 100% by mass of the total amount of components constituting the resin film.

[0031] Furthermore, in one embodiment of the present invention, if the resin film contains a polyvinyl chloride resin as component (A) and further contains the plasticizer, the total content of component (A), component (B), and plasticizer in the resin film is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 80 to 100% by mass, of 100% by mass of the total amount of components constituting the resin film.

[0032] Furthermore, a support may be laminated on the surface of the resin film opposite to the surface in contact with the adhesive composition layer. However, if the first adhesive sheet has a laminate of the resin film and the support, at least one of the adhesive composition layers is laminated on the surface of at least one of the resin films.

[0033] Alternatively, for example, the resin film may be used as the support. For example, in one embodiment of the adhesive sheet, the adhesive composition layer may be laminated on one or both surfaces of a laminate formed by laminating two layers of the resin film. Furthermore, for example, as one embodiment of the adhesive sheet, the adhesive composition layer may be laminated on one or both surfaces of a laminate consisting of two or more layers, each having a resin film and one or more support layers selected from other supports. However, at least one of the adhesive composition layers is laminated on the surface of at least one of the resin films. Furthermore, for example, as one embodiment of the adhesive sheet, the adhesive composition layer may be laminated on one or both surfaces of the laminate, which has a three-layer structure or more, with one or more support layers selected from the resin film and other supports between the two resin films present on both surfaces. However, at least one of the adhesive composition layers is laminated on the surface of at least one of the resin films. In each of the aforementioned laminates, if there are multiple resin films, the multiple resin films may be identical or different. That is, the components constituting the multiple resin films may be identical or different.

[0034] Furthermore, for example, in one embodiment of the adhesive sheet, if the adhesive composition layer is laminated on one surface of the single layer resin film, a double-sided adhesive sheet may be provided in which an adhesive composition layer other than the adhesive composition layer, or an adhesive layer other than the adhesive layer formed from the adhesive composition layer, is laminated on the surface opposite to the surface on which the adhesive composition layer is laminated. Similarly, for example, as one embodiment of the adhesive sheet, in a laminate in which the adhesive composition layer is laminated on one surface of each laminate, a double-sided adhesive sheet may be provided in which an adhesive composition layer other than the adhesive composition layer, or an adhesive layer other than the adhesive layer formed from the adhesive composition layer, is laminated on the surface opposite to the surface on which the adhesive composition layer is laminated.

[0035] Examples of materials used to form the support include resin, metal, paper, and the like. Examples of resins used for the support include vinyl resins such as polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic-modified polyurethane; polysulfone; polyetheretherketone; polyethersulfone; polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; polyamide resins; and fluorine resins. As mentioned above, when using resin as the material for forming the support, component (A) described above may also be used. Examples of metals include aluminum, tin, chromium, and titanium. Examples of paper materials include tissue paper, medium-quality paper, fine-quality paper, impregnated paper, coated paper, art paper, sulfuric acid paper, and glassine paper.

[0036] The supporting material may consist of a single material or a combination of two or more materials. Furthermore, the support may, if necessary, contain one or more of the substrate additives described in the section on resin films.

[0037] Supports using two or more forming materials in combination include paper laminated with a thermoplastic resin such as polyethylene, and resin films containing resin with a metal film formed on the surface. Methods for forming the metal layer include, for example, depositing the metal by PVD methods such as vacuum deposition, sputtering, or ion plating, or attaching a metal foil made of the metal using a general adhesive.

[0038] Furthermore, from the viewpoint of improving interlayer adhesion between the support and other layers laminated together, if the support contains resin, the surface of the support may be subjected to surface treatment by oxidation, embossing, or other methods, or to primer treatment. Furthermore, the support may have, depending on the application of the adhesive sheet, for example, an easy-adhesion layer to facilitate printing; a recording layer to enable recording such as thermal transfer recording or inkjet recording; an overcoat film or overlaminate film to protect these surfaces; an information area for magnetic recording, barcodes, microsemiconductor elements, etc.

[0039] The thickness of the resin film is not particularly limited, but is preferably 5 to 1,000 μm, more preferably 15 to 500 μm, and even more preferably 20 to 200 μm. Furthermore, when using a laminate of the resin film and the support (including a laminate consisting only of multiple resin films, as described above), the thickness of the laminate is also not particularly limited, but is preferably 5 to 2,000 μm, more preferably 15 to 500 μm, and even more preferably 20 to 200 μm.

[0040] (Method of manufacturing resin film) As long as a resin film containing component (A) and component (B) can be produced, there are no particular restrictions on the method of producing the resin film, and it can be produced by known methods such as casting, calendering, or extrusion molding. One embodiment of the method for producing the resin film is, for example, a production method that includes a coating step of applying a resin film-forming composition containing component (A) and component (B), and optionally other components, onto the support or release liner. In this specification, "on the release liner" means the surface on which the release liner has been peeled if it has been peeled on one side. Furthermore, there are no particular limitations on the release liner that can be used in the method for manufacturing the resin film, and the same type of release liner that can be used in the adhesive sheet, which is one embodiment of the present invention and will be described later, can be used.

[0041] In one embodiment of the method for producing the resin film, for example, the resin film may be produced by dissolving or dispersing component (A) and component (B), and any optional components as needed, in a dilution organic solvent, mixing them, and forming a liquid substance such as a solution or sol of the resin film forming composition. The organic solvent is not particularly limited as long as it can dissolve or disperse and mix components (A) and (B), as well as any other components as needed, and can form a coating film in the coating step. Examples of the aforementioned organic solvents include methyl ethyl ketone, methyl isobutyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol, ethylene glycol monobutyl ether, paraffinic hydrocarbons, naphthenic hydrocarbons, and the like.

[0042] When using the liquid form of the resin film-forming composition, the content of the organic solvent in the liquid form of the resin film-forming composition is preferably 10 to 90% by mass, more preferably 15 to 85% by mass, and even more preferably 20 to 80% by mass.

[0043] Furthermore, in the above step, a liquid paste-like resin film-forming composition may be obtained by mixing, for example, the aforementioned plasticizer with component (A) and component (B), and any other components as needed, without using an organic solvent for dilution.

[0044] Furthermore, a method for forming the resin film is described by using, for example, a casting method, to form the resin film from the liquid resin film-forming composition obtained through the above process. For example, the resin film may be formed by applying the liquid resin film-forming composition onto the support or release liner to form a coating film, and then subjecting the coating film to drying, heating, or both.

[0045] Methods for applying the liquid resin film-forming composition onto the support or release liner include, for example, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.

[0046] Furthermore, there are no particular restrictions on the method or temperature used when applying drying, heating, or both of the treatments to the coating film made of the resin film-forming composition. These can be appropriately selected depending on the characteristics of the material forming the resin film-forming composition. Therefore, the temperature of each of the above processes is not particularly limited once the resin film is formed, but as one embodiment of the method for manufacturing the resin film, it is preferable that the temperature is lower than the boiling points of component (A) and component (B), and more preferably lower than the boiling points of component (A), component (B), and any other components included as needed.

[0047] Furthermore, in one embodiment of the method for manufacturing the resin film, for example, the resin film forming composition may be manufactured by a melt-kneading step in which component (A) and component (B), and any optional components as needed, are melt-kneaded together. The melt-mixing process involves, for example, putting each component into a mixing device equipped with a heating device, such as a heated kneader, and mixing the components while they are in a melted state. Mixing equipment equipped with a heating device includes, for example, single-screw extruders, twin-screw extruders, roll mills, Banbury mixers, intermixers, and pressure kneaders. If a mixing device capable of reducing pressure is used, the inside of the mixing device may be depressurized as needed, and the mixture may be melted and kneaded under reduced pressure.

[0048] The temperature during the melting and kneading process is preferably lower than the boiling points of component (A) and component (B), and more preferably lower than the boiling points of component (A), component (B), and any other components included as needed.

[0049] When manufacturing the resin film via a melt-kneading process, the resin film-forming composition obtained in the melt-kneading process may be applied to the support or release liner using an extruder and a T-die, while it is still heated and molten, thereby forming the resin film. Alternatively, the resin film-forming composition obtained in the melt-kneading process may be cooled to form pellets, powder, etc., and then heated and melted again before application. Furthermore, without using the support or release liner, the resin film may be formed from the resin film-forming composition obtained in the melt-kneading process or the reheated and melted molten material using a calender, a T-die, or the like. The process may then include a step of cooling the resin film, if necessary.

[0050] <Adhesive layer> The adhesive layer is formed by irradiating an energy ray crosslinkable adhesive composition layer, which is made of an energy ray crosslinkable adhesive composition, with energy rays. That is, as described above, it is formed by irradiating the adhesive composition layer of the first adhesive sheet with energy rays.

[0051] (Energy ray crosslinkable adhesive composition layer) The energy-ray crosslinkable adhesive composition layer of the first adhesive sheet is made of an energy-ray crosslinkable adhesive composition. When energy rays are irradiated onto the energy-ray crosslinkable adhesive composition layer, the adhesive layer of the second adhesive sheet is formed.

[0052] The energy-ray crosslinkable adhesive composition forms a crosslinked structure and becomes a crosslinked adhesive when irradiated with energy rays. In other words, the adhesive composition is intended to be irradiated with energy rays before or after being applied to an adherend. The adhesive composition can be irradiated with energy rays at any time. Therefore, the adhesive composition offers a high degree of flexibility in its manufacturing method and usage method.

[0053] The aforementioned adhesive composition is an adhesive composition having energy ray crosslinking properties, and is not particularly limited as long as the effects of the present invention are achieved. The energy-ray crosslinkable adhesive composition is preferably an adhesive composition (I) containing (C) an acrylic polymer having energy-ray crosslinkability, or an adhesive composition (II) containing (D) an acrylic polymer other than component (C) and (B) a hydrogen abstraction type photoinitiator.

[0054] [Adhesive composition (I)] The adhesive composition (I) contains (C) an acrylic polymer having energy ray crosslinking properties (hereinafter also referred to as "component (C)").

[0055] {(C) Acrylic polymer with energy ray crosslinking properties} Component (C) is not particularly limited as long as it is an acrylic polymer having energy ray crosslinking properties. In the adhesive composition (I), component (C) may be used alone or in combination of two or more types.

[0056] Examples of component (C) include (C1) an acrylic polymer having energy-ray reactive groups that react upon energy-ray irradiation and contribute to the formation of a crosslinked structure (hereinafter also referred to as "component (C1)"), or (C2) an acrylic polymer that does not have energy-ray reactive groups but has energy-ray polymerizable groups (hereinafter also referred to as "component (C2)"), with component (C1) being preferred.

[0057] {{(C1) Acrylic polymer having energy-ray reactive groups}} Examples of energy-ray reactive groups in component (C1) include those that are excited by irradiation with energy rays and generate radicals that trigger a crosslinking reaction. Specific examples of energy-ray reactive groups include functional groups having structures such as benzophenone, benzyl, o-benzoylbenzoate, thioxanthone, 3-ketocoumarin, 2-ethylanthraquinone, and camphorquinone. Among these, the component (C1) is preferably one having a benzophenone structure in its side chain. If component (C1) has a benzophenone structure, for example, by irradiation with energy rays, the benzophenone structure extracts hydrogen atoms from hydrocarbon groups contained in the side chains of the acrylic polymer, and the resulting radicals recombine to form a crosslinked structure. Furthermore, from the viewpoint of facilitating the formation of crosslinked structures, it is preferable that the energy-ray reactive group is introduced into the side chain of the acrylic polymer. That is, component (C1) is preferably an acrylic polymer having a benzophenone structure in its side chain.

[0058] The content of energy-ray reactive groups in component (C1) is preferably 0.02 to 5.0% by mass, more preferably 0.05 to 3.0% by mass, based on the total amount of component (C) (100% by mass).

[0059] As a method for introducing the energy-ray reactive group in component (C1), for example, a monomer having a functional group such as a vinyl group that can react with acrylic monomers, and having the energy-ray reactive group, may be copolymerized with the acrylic monomer. Alternatively, for example, a compound having the energy-ray reactive group may be introduced by reacting it with the side chain of an acrylic polymer using a known method.

[0060] The aforementioned component (C1) is a polymer containing an acrylic monomer as a monomer component, and is not particularly limited as long as it has an energy-ray reactive group, but it is preferable that it contains a structural unit derived from alkyl (meth)acrylate. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate. Among these, alkyl (meth)acrylates with 1 to 8 carbon atoms in the alkyl group are preferred, and 2-ethylhexyl (meth)acrylate, methyl (meth)acrylate, and butyl (meth)acrylate are more preferred. Furthermore, these alkyl (meth)acrylates may be used individually or in combination of two or more types.

[0061] In component (C1), the content of constituent units derived from alkyl (meth)acrylate is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and even more preferably 98 to 100% by mass, of the total constituent units (100% by mass) of component (C1). In this specification, the content of monomer constituent units relative to all constituent units (100% by mass) of component (C1) may also be considered as the content of the monomer in 100% by mass of the total amount of monomer blended when synthesizing component (C1). Furthermore, unless otherwise specified, the total constituent units (100% by mass) of component (C1) do not include, for example, constituent units derived from polymerization initiators, chain transfer agents, and compounds having energy-ray reactive groups used in the polymerization of the polymer.

[0062] Furthermore, the constituent units derived from monomers that constitute the acrylic polymer may, if necessary, include constituent units derived from monomers other than alkyl (meth)acrylate. Examples of other monomers other than alkyl (meth)acrylate that can be used in component (C1) include monomer (c22), monomer (c23), etc., which will be described later.

[0063] The weight-average molecular weight (Mw) of component (C1) is not particularly limited as long as the effects of the present invention are achieved, but for example, it is preferably 10,000 to 2,000,000, more preferably 50,000 to 1,500,000, and even more preferably 100,000 to 1,000,000. Furthermore, for example, in one embodiment of the present invention, when the adhesive composition (I) is used as a hot-melt adhesive, the weight-average molecular weight (Mw) of component (C1) is preferably 10,000 to 500,000, more preferably 50,000 to 400,000, and even more preferably 100,000 to 300,000.

[0064] If the adhesive composition (I) contains component (C1) as component (C), the content of component (C1) in the adhesive composition (I) is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass, and may also be 100% by mass, based on 100% by mass of the total amount of the adhesive composition (I). Furthermore, if the adhesive composition (I) is diluted with an organic solvent or water, as described later, the "total amount of the adhesive composition" refers to the total amount of solids excluding the diluting solvent. The same applies to the adhesive composition (II) described later.

[0065] {{(C2) Acrylic polymer that does not have energy-ray reactive groups and has energy-ray polymerizable groups}} The aforementioned component (C2) is an acrylic polymer that does not have the aforementioned energy-ray reactive group, has an energy-ray polymerizable group introduced into it, and has a structural unit derived from (meth)acrylate. The energy-ray polymerizable group is preferably introduced into the side chain of the acrylic polymer.

[0066] Unlike the energy-ray reactive groups mentioned above, the aforementioned energy-ray polymerizable groups do not themselves generate radicals that trigger crosslinking reactions when irradiated with energy rays, but are groups that can be polymerized by radicals generated by radical polymerization initiators or the like. For example, any group containing an energy-ray polymerizable carbon-carbon double bond is acceptable, and examples include (meth)acryloyl groups and vinyl groups, with (meth)acryloyl groups being preferred.

[0067] Component (C2) preferably contains an acrylic copolymer (C2az) (hereinafter also referred to as "component (C2az)") which is a reaction product obtained by reacting an acrylic copolymer (C2a) (hereinafter also referred to as "component (C2a)") having structural units derived from alkyl (meth)acrylate (c21) and structural units derived from functional group-containing monomer (c22) with a polymerizable compound (Zc) having an energy-ray polymerizable group. The copolymerization form of component (C2a) is not particularly limited and may be a block copolymer, a random copolymer, or any other. The content of component (C2az) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass, based on the total amount (100% by mass) of component (C2) contained in the adhesive composition.

[0068] Preferably, alkyl (meth)acrylates (C21) (hereinafter also referred to as "monomer (C21)") include alkyl (meth)acrylates in which the alkyl group has 1 to 18 carbon atoms. Specifically, the same alkyl (meth)acrylates exemplified as the monomer component of component (C1) above are included. The monomer (C21) may be used alone or in combination of two or more types. Among the monomers (C21) mentioned above, alkyl (meth)acrylates with 1 to 8 carbon atoms in the alkyl group are more preferred.

[0069] The content of constituent units derived from monomer (c21) in component (C2a) is not particularly limited as long as the effects of the present invention are achieved. For example, it is preferably 50 to 99% by mass, more preferably 60 to 98% by mass, and even more preferably 70 to 97% by mass, relative to the total constituent units (100% by mass) of component (C2a).

[0070] Functional group-containing monomers (C22) (hereinafter also referred to as "monomers (C22)") are monomers having functional groups such as hydroxyl groups, carboxyl groups, epoxy groups, amino groups, cyano groups, nitrogen atom-containing ring groups, and alkoxysilyl groups. Among the above, it is preferable that monomers (C22) be one or more selected from hydroxyl group-containing monomers, carboxyl group-containing monomers, and epoxy group-containing monomers. The monomer (C22) may be used alone or in combination of two or more types.

[0071] Examples of the hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

[0072] Examples of the carboxyl group-containing monomers include ethylenically unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid.

[0073] Examples of epoxy-containing monomers include epoxy group-containing (meth)acrylic acid esters and non-acrylic epoxy group-containing monomers. Examples of epoxy group-containing (meth)acrylic acid esters include glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and 3-epoxycyclo-2-hydroxypropyl (meth)acrylate. Examples of non-acrylic epoxy group-containing monomers include glycidyl crotonate and allyl glycidyl ether.

[0074] Furthermore, as the monomer (C22), a monomer containing a hydroxyl group is preferred, and among these, various hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate are more preferred, with 2-hydroxyethyl (meth)acrylate being even more preferred. By using hydroxyalkyl (meth)acrylate, it becomes possible to react the polymerizable compound (Zc) with component (C2a) relatively easily.

[0075] The content of constituent units derived from monomer (c22) in component (C2a) is not particularly limited as long as the effects of the present invention are achieved. For example, it is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass, relative to the total constituent units (100% by mass) of component (C2a). If the content of the constituent units derived from the monomer (c22) is 1% by mass or more, a certain amount of functional groups that serve as reaction sites with the polymerizable compound (Zc) can be secured. Therefore, the adhesive layer can be appropriately crosslinked by irradiation with energy rays. Furthermore, if the content of the constituent units derived from the monomer (c22) is 20% by mass or less, sufficient adhesive strength can be obtained.

[0076] Component (C2a) may be a copolymer consisting only of constituent units derived from monomer (c21) and monomer (c22) (excluding constituent units derived from components other than monomers, such as polymerization initiators and chain transfer agents), or it may be a copolymer that further includes constituent units derived from monomer (c21) and monomer (c22), as well as other monomers (c23) other than monomers (c21) and (c22) (hereinafter also referred to as "monomer (c23)").

[0077] Examples of monomers (C23) include cyclic (meth)acrylates such as cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate, as well as vinyl acetate and styrene. The monomer (C23) may be used alone or in combination of two or more types. When component (C2a) contains constituent units derived from monomer (c23), the content of monomer (c23)-derived constituent units in component (C2a) is not particularly limited as long as the effects of the present invention are achieved. For example, it is preferably 1 to 30% by mass, more preferably 1 to 20% by mass, and even more preferably 1 to 10% by mass, relative to the total constituent units (100% by mass) of component (C2a).

[0078] A polymerizable compound (Zc) is a compound having an energy-ray polymerizable group and a substituent (hereinafter also referred to as a "reactive substituent") that can react with a functional group in the constituent unit derived from the monomer (c22) of component (C2a). As mentioned above, examples of energy-ray polymerizable groups include (meth)acryloyl groups and vinyl groups, with (meth)acryloyl groups being preferred. Furthermore, the polymerizable compound (Zc) is preferably a compound having 1 to 5 energy-ray polymerizable groups per molecule. The reactive substituent in the polymerizable compound (Zc) can be appropriately changed depending on the functional group of the monomer (C22), but examples include isocyanate groups, carboxyl groups, epoxy groups, etc., and an isocyanate group is preferred from the viewpoint of reactivity, etc. When the polymerizable compound (Zc) has an isocyanate group, it can readily react with component (C2a), for example, when the functional group of the monomer (C22) is a hydroxyl group.

[0079] Specific polymerizable compounds (Zc) include, for example, 2-(meth)acryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, allyl isocyanate, glycidyl (meth)acrylate, and (meth)acrylic acid. These polymerizable compounds (Zc) may be used individually or in combination of two or more. Among these, 2-(meth)acryloyloxyethyl isocyanate is preferred, and 2-methacryloyloxyethyl isocyanate is more preferred, from the viewpoint of having an isocyanate group suitable as the reactive substituent and having an appropriate distance between the main chain and the energy-ray polymerizable group. Component (C2az) is obtained by the reaction of a polymerizable compound (Zc) with a preferably 40 to 98 molar equivalents, more preferably 50 to 95 molar equivalents, and even more preferably 60 to 90 molar equivalents, of the total amount (100 molar equivalents) of functional groups derived from the monomer (c22) in component (C2a).

[0080] The weight-average molecular weight (Mw) of component (C2) is not particularly limited as long as the effects of the present invention are achieved, but for example, it is preferably 100,000 to 1,500,000, more preferably 250,000 to 1,000,000, and even more preferably 300,000 to 900,000.

[0081] If the adhesive composition (I) contains component (C2) as component (C), the content of component (C2) in the adhesive composition (I) is not particularly limited as long as the effects of the present invention are achieved. For example, it is preferably 55 to 99% by mass, more preferably 65 to 98% by mass, and even more preferably 75 to 96% by mass, of 100% by mass of the total amount of the adhesive composition (I).

[0082] Photopolymerization initiator If the adhesive composition (I) contains component (C2) as component (C), it is preferable to further contain a photopolymerization initiator. When the adhesive composition (I) contains component (C2) as component (C), the inclusion of a photopolymerization initiator facilitates the crosslinking of the adhesive composition by energy rays such as ultraviolet light. Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds, azo compounds, peroxide compounds, and photosensitizers such as amines and quinones. The photopolymerization initiator may be used alone or in combination of two or more types. The content of the photopolymerization initiator is preferably 0.3 to 15 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of component (C2).

[0083] Furthermore, the adhesive composition (I) may also contain polymers other than component (C) in addition to component (C). The polymers other than component (C) are not particularly limited as long as the effects of the present invention are achieved, but examples include (D) acrylic polymers other than component (C) (hereinafter also referred to as "component (D)") described later, and (E) resins other than component (C) described later, which are energy-ray curable adhesive resins in which energy-ray polymerizable functional groups are introduced into the side chains (hereinafter also referred to as "component (E)"). Furthermore, if necessary, it may also contain one or more components selected from component (B) and other components described later. However, in the case of a composition containing polymers other than component (C), such as component (D) and component (B), an adhesive composition in which the content of component (C) is greater than that of component (D) shall be deemed to be adhesive composition (I), while an adhesive composition in which the content of component (D) is greater than that of component (C) shall be deemed to be adhesive composition (II) described below.

[0084] [Adhesive composition (II)] The adhesive composition (II) contains an acrylic polymer other than component (D) (C), and a hydrogen abstraction type photoinitiator (B).

[0085] {(D) Acrylic polymer other than (C)} Component (D) is not particularly limited as long as it is an acrylic polymer other than component (C) and the effects of the present invention are achieved. Component (D) may be used alone or in combination of two or more types.

[0086] Component (D) is not particularly limited as long as it is a polymer containing an acrylic monomer as a monomer component, but it is preferable that it contains a structural unit derived from alkyl (meth)acrylate (d1). As for the alkyl (meth)acrylate (d1) (hereinafter also referred to as "monomer (d1)") that can be used in component (D), for example, an alkyl (meth)acrylate having 1 to 18 carbon atoms in the alkyl group is preferably used. Specifically, the same alkyl (meth)acrylate exemplified as the monomer component of component (C1) can be used. The monomer (d1) may be used alone or in combination of two or more types. Among the monomers (d1) mentioned above, alkyl (meth)acrylates with 1 to 8 carbon atoms in the alkyl group are more preferred.

[0087] In component (D), the content of constituent units derived from monomer (d1) is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, and even more preferably 85 to 100% by mass, out of the total constituent units (100% by mass) of component (D). Furthermore, if component (D) also includes one or more constituent units selected from the monomers (d2) and (d3) below as one embodiment, the content of constituent units derived from monomer (d1) is preferably 60 to 99.5% by mass, more preferably 70 to 99% by mass, even more preferably 80 to 96% by mass, and even more preferably 85 to 95% by mass, of the total constituent units (100% by mass) of component (D).

[0088] Furthermore, component (D) may be an acrylic copolymer that contains, in addition to the constituent units derived from monomer (d1), constituent units derived from functional group-containing monomer (d2) (hereinafter also referred to as "monomer (d2)"). Examples of monomer (d2) include monomers having the functional group exemplified as monomer (c22). Among these, when used as monomer (d2), carboxyl group-containing monomers are more preferred, (meth)acrylic acid is even more preferred, and acrylic acid is even more preferred. The monomer (d2) may be used alone or in combination of two or more types.

[0089] If component (D) contains constituent units derived from monomer (d2), the content of constituent units derived from monomer (d2) in component (D) is preferably 0.5 to 40% by mass, more preferably 1 to 30% by mass, even more preferably 4 to 20% by mass, and even more preferably 5 to 15% by mass, relative to the total constituent units (100% by mass) of component (D).

[0090] Furthermore, component (D) may be an acrylic copolymer containing, in addition to the constituent units derived from monomer (d1), constituent units derived from monomer (d1) and monomer (d2), as well as other monomers (d3) (hereinafter also referred to as "monomer (d3)"); or an acrylic copolymer containing, in addition to the constituent units derived from monomer (d1) and monomer (d2), constituent units derived from monomer (d3). Examples of monomers (d3) include those exemplified as monomer (c23) mentioned above. The monomer (d3) may be used alone or in combination of two or more types.

[0091] If component (D) contains constituent units derived from monomer (d3), the content of constituent units derived from monomer (d3) in component (D) is preferably 0.5 to 40% by mass, more preferably 1 to 30% by mass, even more preferably 4 to 20% by mass, and even more preferably 5 to 15% by mass, relative to the total constituent units (100% by mass) of component (D).

[0092] If component (D) contains constituent units derived from monomer (d1) in addition to constituent units derived from monomer (d2) and monomer (d3), the total content of constituent units derived from monomer (d1) and constituent units derived from monomer (d2) and monomer (d3) in component (D) is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and even more preferably 98 to 100% by mass, and may also be 100% by mass, relative to the total constituent units (100% by mass) of component (D).

[0093] Furthermore, if component (D) is an acrylic copolymer containing structural units derived from multiple monomers (d1); or an acrylic copolymer containing structural units derived from one or more monomers (d2) and one or more monomers (d3), and structural units derived from one or more monomers (d1), the form of copolymerization is not particularly limited and may be a block copolymer or a random copolymer.

[0094] Furthermore, in one embodiment of the present invention, when the adhesive composition (II) is used as a hot-melt adhesive, it is preferable that component (D) substantially does not contain radical-reactive unsaturated double bonds. If component (D) substantially does not contain radically reactive unsaturated double bonds, when the adhesive composition (II) is heated, the polymerization reaction of component (D) is prevented or suppressed, and the increase in viscosity of the adhesive composition (II) over time can be suppressed. As a result, it is preferable that the pot life of the adhesive composition can be extended. The term "radical-reactive unsaturated double bond" refers to an unsaturated double bond that can participate in radical reactions through heating or energy irradiation. This includes both unsaturated double bonds that generate active sites for radical reactions by reacting with radicals generated from components other than component (D), such as initiators, and unsaturated double bonds that are themselves activated by heating or energy irradiation to generate radicals and initiate the reaction.

[0095] An example of the radical-reactive unsaturated double bond is a radical-reactive carbon-carbon double bond. Examples of functional groups containing a radical-reactive carbon-carbon double bond include (meth)acryloyl groups, vinyl groups, and allyl groups.

[0096] Furthermore, the statement that component (D) "substantially does not contain radically reactive unsaturated double bonds" means, for example, that the content of constituent units derived from monomers that still have radically reactive unsaturated double bonds after polymerization is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less, among the total constituent units (100% by mass) of component (D). In this specification, the content of monomer constituent units relative to all constituent units (100% by mass) of component (D) may also be considered as the content of the monomer in 100% by mass of the total amount of monomer blended when synthesizing component (D). Furthermore, unless otherwise specified, the total constituent units (100% by mass) of component (D) do not include, for example, constituent units derived from polymerization initiators and chain transfer agents used in the polymerization of the polymer.

[0097] Furthermore, for example, in one embodiment of the present invention, when the adhesive composition (II) is diluted with a solvent and applied, the weight-average molecular weight (Mw) of component (D) is not particularly limited as long as the effects of the present invention are achieved, but is preferably 10,000 to 2,000,000, more preferably 50,000 to 1,500,000, and even more preferably 100,000 to 1,000,000. Furthermore, for example, in one embodiment of the present invention, when the adhesive composition (II) is melt-applied as a hot-melt adhesive, it is preferable that the weight-average molecular weight (Mw) of component (D) be 280,000 or less, from the viewpoint of improving the coatability of the adhesive composition (II). From the viewpoint of improving the coating properties of the adhesive composition (II), the weight-average molecular weight (Mw) of component (D) is more preferably 270,000 or less, and even more preferably 260,000 or less. Also, the weight-average molecular weight (Mw) of component (B) is preferably 1,000 or more, more preferably 5,000 or more, and even more preferably 10,000 or more.

[0098] The content of component (D) in the adhesive composition (II) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 97% by mass or less, based on 100% by mass of the total amount of the adhesive composition (II).

[0099] Furthermore, the adhesive composition (II) may also contain polymers other than component (D) in addition to component (D). The polymers other than component (D) are not particularly limited as long as the effects of the present invention are achieved, but examples include acrylic polymers other than component (D), component (E) described later, etc. Furthermore, it may contain one or more of the other ingredients described below, as needed.

[0100] {(B) Hydrogen abstraction type photoinitiator} The hydrogen abstraction type photoinitiator (B) contained in the adhesive composition (II) is the same as component (B) described above in the section on resin film, and its specific examples are also the same as described above. Among these, it is preferable to use a compound containing benzophenone from the viewpoint of ease of radical generation. In the adhesive composition (II), component (B) may be used alone or in combination of two or more types. Furthermore, the component (B) contained in the resin film and the component (B) contained in the adhesive composition layer (II) may be the same or different.

[0101] The content of component (B) in the adhesive composition (II) is not particularly limited as long as the effects of the present invention are achieved, but from the viewpoint of obtaining an adhesive sheet that can be peeled off without further contamination of the adherend, for example, it is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 9 parts by mass or less, and even more preferably 8 parts by mass or less, per 100 parts by mass of component (D).

[0102] Furthermore, from the viewpoint of making the effects of the present invention easier to achieve, the total content of component (D) and component (B) in the adhesive composition (II) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, and 100% by mass or less, based on 100% by mass of the total amount of the adhesive composition (II).

[0103] [Other energy ray crosslinkable adhesive compositions] Furthermore, in one embodiment of the present invention, other energy ray adhesive compositions other than the adhesive compositions (I) or (II) described above may be used. Other energy ray adhesive compositions include, for example, adhesive compositions that mainly contain an energy ray-curable adhesive resin (hereinafter also referred to as component (E)) other than component (C), in which an energy ray polymerizable functional group is introduced into the side chain.

[0104] Examples of the adhesive resin in component (E) include rubber resins such as polyisobutylene resins, urethane resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins. Furthermore, if these adhesive resins are copolymers having two or more constituent units, the form of the copolymer is not particularly limited and may be a block copolymer, a random copolymer, an alternating copolymer, or a graft copolymer. Furthermore, the energy-ray polymerizable functional group in component (E) may be any group containing an energy-ray polymerizable carbon-carbon double bond, such as a (meth)acryloyl group, a vinyl group, or an allyl group.

[0105] Furthermore, when using an adhesive composition containing component (E), it may also contain an initiator that generates radicals by energy rays, such as a photopolymerization initiator. It may also contain a crosslinking agent. Examples of photopolymerization initiators and crosslinking agents are the same as those exemplified in the section on adhesive composition (II).

[0106] Component (E) is preferably a polymer that is adhesive on its own. The weight-average molecular weight (Mw) of the adhesive resin component (E) is not particularly limited as long as the effects of the present invention are achieved, but for example, it is preferably 10,000 to 2,000,000.

[0107] {Other components} Each of the adhesive compositions described above may or may not contain other components other than those described above, as long as the effects of the present invention are achieved. Other components include, for example, tackifiers; antioxidants; softeners; and adhesive additives used in general adhesives. Each of these other components may be used individually or in combination of two or more.

[0108] The tackifier is a component that can improve the tackiness of the resulting adhesive, and is not particularly limited as long as the effects of the present invention are achieved. Conventionally known components can be used, for example, rosin resins and their hydrides (hydrogenated rosin resins), terpene resins and their hydrides (hydrogenated terpene resins), petroleum resins and their hydrides (hydrogenated petroleum resins), styrene resins and their hydrides (hydrogenated styrene resins), and the like. The tackifier may be used alone or in combination of two or more types.

[0109] The softening point of the tackifier is preferably 70 to 140°C. In this specification, the softening point of the tackifier refers to the value measured in accordance with JIS K 5601-2-2:1999.

[0110] The antioxidant is not particularly limited, and conventionally known antioxidants can be used, such as hindered phenol antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. Antioxidants may be used individually or in combination of two or more types.

[0111] Examples of adhesive additives used in the above-mentioned general adhesives include waxes, fillers, bulking agents, heat stabilizers, light stabilizers, UV absorbers, colorants (pigments, dyes, etc.), flame retardants, antistatic agents, stringing inhibitors, leveling agents, crosslinking agents, crosslinking aids, anti-aging agents, inorganic particles, organic particles, and weight-reducing agents. Each of these adhesive additives may be used individually or in combination of two or more types.

[0112] However, if the adhesive composition contains one or more of the other components selected above, the total content of each component and the other components in the aforementioned adhesive composition shall be 100% by mass or less of the total amount of the adhesive composition.

[0113] Furthermore, when adhesive composition (II) is used as the adhesive composition, and the adhesive composition is of the hot-melt type, it is preferable that it substantially does not contain compounds having radical-reactive unsaturated double bonds, such as polyfunctional acrylates, from the viewpoint of suppressing viscosity increase during prolonged heating. Here, "substantially free of compounds having radical-reactive unsaturated double bonds" means, for example, that the content of compounds having radical-reactive unsaturated double bonds in 100% by mass of the total amount of the adhesive composition is preferably 1.0% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less.

[0114] [Method for manufacturing adhesive composition] One embodiment of the production of the adhesive composition is, for example, a kneading method in which the aforementioned components are melted and kneaded together. When melting and kneading, for example, each component may be placed in a mixing device equipped with a heating device, such as a heated kneader, and mixed while each component is melted. Mixing equipment equipped with a heating device includes, for example, single-screw extruders, twin-screw extruders, roll mills, Banbury mixers, intermixers, and pressure kneaders. If a mixing device capable of reducing pressure is used, the inside of the mixing device may be depressurized as needed, and the mixture may be melted and kneaded under reduced pressure.

[0115] The mixing temperature during melt mixing is not particularly limited, and any temperature condition that allows each component to be thoroughly mixed in a molten state should be appropriately selected, but it is preferably 80 to 180°C, more preferably 100 to 170°C, and even more preferably 120 to 150°C.

[0116] Furthermore, when the adhesive composition is manufactured by melt kneading, the adhesive composition does not need to contain a solvent, and from the viewpoint of reducing the environmental burden, it is preferable that it is substantially solvent-free, and more preferable that it is solvent-free. Here, "substantially solvent-free" means, for example, that the solvent content in 100% by mass of the total amount of the adhesive composition is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. Furthermore, the term "melt kneading" in the method for producing the adhesive composition includes cases where the adhesive composition contains only one component and is used after being melted.

[0117] The adhesive composition obtained after melt-kneading may be applied to at least one surface of the resin film or onto a release liner using an extruder or the like while still in its heated and molten state, and then used to manufacture an adhesive sheet according to one embodiment of the present invention, as described later.

[0118] Furthermore, one embodiment of the production of the adhesive composition may involve, for example, mixing or dispersing the aforementioned components in a diluting organic solvent to obtain a liquid substance such as a solution or sol of the adhesive composition. Examples of the dilution organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol, and the like. The organic solvent used may be, for example, the same organic solvent used during the synthesis of polymers such as component (C) and component (D) contained in the adhesive composition, or one or more organic solvents other than those used during the synthesis of the polymer may be added. When using the liquid form of the adhesive composition, the content of the organic solvent in the liquid form of the adhesive composition is preferably 30 to 90% by mass, more preferably 40 to 85% by mass, and even more preferably 50 to 80% by mass.

[0119] Furthermore, the adhesive composition layer in the first adhesive sheet and the adhesive layer in the second adhesive sheet may each be a single layer or formed from multiple layers. The thickness of the adhesive composition layer in the first adhesive sheet and the thickness of the adhesive layer in the second adhesive sheet are, independently, preferably 5 to 100 μm, more preferably 10 to 60 μm, and even more preferably 15 to 30 μm. When the thickness of the adhesive composition layer and the adhesive layer is 5 μm or more, it tends to be easier to improve the adhesive strength. Also, when the thickness of the adhesive composition layer and the adhesive layer is 100 μm or less, it tends to be easier to handle. Here, the "thickness of the adhesive composition layer" refers to the total thickness of the adhesive composition layer. For example, when using two or more laminated adhesive composition layers, the thickness of the adhesive composition layer refers to the total thickness of all the layers constituting the adhesive composition layer. The same applies to the "thickness of the adhesive layer."

[0120] Here, the laminate of the substrate and the adhesive layer included in the second adhesive sheet is formed by irradiating the laminate of the resin film and the energy-ray crosslinkable adhesive composition layer with energy rays. In other words, it is necessary to perform the energy ray irradiation after laminating the resin film and the energy-ray crosslinkable adhesive composition layer. After laminating the resin film and the energy-ray crosslinkable adhesive composition layer, energy-ray irradiation is performed, causing the crosslinking reaction of the energy-ray crosslinkable adhesive composition layer and the reaction in which radicals are generated on component (A) based on components (A) and (B) in the resin film described above to proceed approximately simultaneously. As a result, component (A) in the resin film undergoes a direct crosslinking reaction with the polymer component in the adhesive composition, which is thought to improve adhesion at the interface between the substrate and the adhesive layer in the second adhesive sheet formed by irradiation with energy rays. Consequently, the second adhesive sheet has excellent adhesion to the substrate and can be peeled off without contaminating the adherend. Therefore, for example, even if the resin film is irradiated with energy rays beforehand to form a substrate before laminating the resin film and the energy-ray crosslinkable adhesive composition layer, and then the energy-ray crosslinkable adhesive composition layer is laminated onto the substrate and then irradiated with energy rays to form the adhesive layer, the effects of the present invention cannot be fully achieved. Alternatively, the same applies if an adhesive layer, which has been formed in advance by irradiating the energy-ray crosslinkable adhesive composition layer with energy rays, is laminated onto the substrate. This is thought to be because the cross-linking reactions within each layer are almost complete, and there is little or no reaction between components of other layers through the interfaces of each layer.

[0121] As described above, in the laminate of the substrate and the adhesive layer included in the second adhesive sheet, it is considered that a molecular structure is formed at the interface between the substrate and the adhesive layer through the reaction of the components of each layer with each other. Therefore, from a very microscopic viewpoint, it is considered that there are structural differences between the laminate of the substrate and the adhesive layer obtained by performing energy ray irradiation after laminating the resin film and the energy ray crosslinkable adhesive composition layer, and the laminate of the substrate and the adhesive layer obtained by performing energy ray irradiation on one or both layers before laminating the resin film and the energy ray crosslinkable adhesive composition layer as described above. However, it is extremely difficult to distinguish the obtained laminates by evaluating, for example, the molecular structure near the interface between the substrate and the adhesive layer, based on differences in their microscopic structure. Furthermore, it is currently practically difficult to clearly analyze and identify the reaction sites within the molecules of each layer. Therefore, since it is impossible or impractical to directly identify the laminates based on their specific chemical structure, the laminates of the substrate and adhesive layer included in the second adhesive sheet are identified by their manufacturing method.

[0122] <Removable Liner> Examples of the aforementioned release liner include release liners that have undergone double-sided release treatment, release liners that have undergone single-sided release treatment, etc., and release liners in which a release agent is applied to a substrate for the release liner. Examples of substrates for release liners include papers such as fine paper, glassine paper, and kraft paper; plastic films such as polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin; and polyolefin resin films such as polypropylene resin and polyethylene resin. Examples of release agents include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins; and long-chain alkyl resins, alkyd resins, and fluororesins. The thickness of the release liner is not particularly limited, but is preferably 10 to 200 μm, more preferably 20 to 180 μm, and even more preferably 30 to 150 μm.

[0123] [Method for manufacturing the first adhesive sheet] There are no particular limitations on the method for manufacturing the first adhesive sheet, but examples include a method for manufacturing an adhesive sheet having the following steps 1 and 2. In other words, an adhesive sheet comprising a laminate of a resin film and an energy-ray crosslinkable adhesive composition layer, wherein the resin film contains (A) a polymer and (B) a hydrogen abstraction type photoinitiator, and component (A) is a polymer capable of hydrogen abstraction by component (B), a method for manufacturing an adhesive sheet, A method for manufacturing an adhesive sheet, comprising the following steps 1 and 2 in this order. Step 1: A step of forming a resin film containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator. Step 2: A step of laminating the resin film obtained in Step 1 with an energy ray crosslinkable adhesive composition layer made of an energy ray crosslinkable adhesive composition to form a laminate of the resin film and the energy ray crosslinkable adhesive composition layer.

[0124] (Process 1) The resin film obtained in step 1 is the same as the resin film in one embodiment of the present invention, and the preferred embodiment is also the same. Therefore, the description of step 1 is as described in the description of the method for manufacturing the resin film, which is one aspect of the present invention.

[0125] (Process 2) The energy ray crosslinkable adhesive composition layer formed in step 2 is the same as the adhesive composition layer described in the section on adhesive sheets, which is one embodiment of the present invention, and the preferred embodiment is also the same. Therefore, the method for producing the energy ray crosslinkable adhesive composition used in step 2 is as described in the description of the method for producing the adhesive composition, which is one aspect of the present invention. For example, step 2 may be the following step 2A or step 2B.

[0126] Step 2A: A step of forming a laminate of the resin film and the energy ray crosslinkable adhesive composition layer by directly forming an energy ray crosslinkable adhesive composition layer made of the energy ray crosslinkable adhesive composition on at least one surface of the resin film obtained in Step 1.

[0127] Step 2B: A step in which an energy ray crosslinkable adhesive composition layer is formed on a release liner, and then the exposed surface of the adhesive composition layer is bonded to at least one surface of the resin film obtained in Step 1 to form a laminate of the resin film and the energy ray crosslinkable adhesive composition layer.

[0128] In step 2A or step 2B, the following is an example of a method for forming the energy ray crosslinkable adhesive composition layer on at least one surface of the resin film obtained in step 1, or on the release liner. For example, the adhesive composition layer may be formed by applying the energy-ray crosslinkable adhesive composition obtained by melt-kneading onto at least one surface of the resin film obtained in step 1 or onto a release liner while it is still heated and molten. Alternatively, after forming the adhesive composition, the process may include a step to cool the adhesive composition layer as needed. An extruder and a T-die can be used for the application.

[0129] Alternatively, for example, the adhesive composition layer may be formed by applying a liquid of the energy ray crosslinkable adhesive composition, such as a solution or sol of the energy ray crosslinkable adhesive composition, to at least one surface of the resin film obtained in step 1 or onto a release liner, thereby forming a coating film made of the adhesive composition, and then subjecting the coating film to drying, heating, or both of these treatments.

[0130] Methods for applying the liquid energy ray crosslinkable adhesive composition onto the support or release liner include, for example, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.

[0131] Furthermore, there are no particular restrictions on the method or temperature used when applying drying, heating, or both of the treatments to the coating film made of the adhesive composition. These can be appropriately selected depending on the properties of the materials forming the adhesive composition. Therefore, the processing temperatures are not particularly limited as long as the adhesive composition layer is formed by drying the coating film, but it is more preferable that they be lower than the boiling points of each component of the energy-ray crosslinkable adhesive composition. Furthermore, for example, if the liquid of the energy-ray crosslinkable adhesive composition contains the organic solvent, it is more preferable that the temperature of each treatment is above the boiling point of the organic solvent and lower than the boiling point of each component of the energy-ray crosslinkable adhesive composition.

[0132] [Method for manufacturing the second adhesive sheet] The method for manufacturing the second adhesive sheet is not particularly limited, but it includes at least the step of irradiating a laminate of a resin film and an energy-ray crosslinkable adhesive composition layer made of an energy-ray crosslinkable adhesive composition with energy rays to form a laminate of a substrate and an adhesive layer. Here, the laminate of the resin film and the energy ray crosslinkable adhesive composition layer in the process is the same as the first adhesive sheet, and the preferred embodiment is also the same. Therefore, one embodiment of the second method for manufacturing an adhesive sheet is, for example, a method for manufacturing an adhesive sheet having the following steps 1 to 3. An adhesive sheet comprising a laminate of a substrate and an adhesive layer, The substrate is formed by irradiating a resin film containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator with energy rays, wherein component (A) is a polymer capable of hydrogen abstraction by component (B), The adhesive layer is formed by irradiating an energy ray crosslinkable adhesive composition layer, which is made of an energy ray crosslinkable adhesive composition, with energy rays. A method for manufacturing an adhesive sheet, wherein the laminate of the substrate and the adhesive layer is formed by irradiating the laminate of the resin film and the energy-ray crosslinkable adhesive composition layer with energy rays, A method for manufacturing an adhesive sheet, comprising the following steps 1 to 3 in this order. Step 1: A step of forming a resin film containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator. Step 2: A step of laminating the resin film obtained in Step 1 with an energy ray crosslinkable adhesive composition layer made of an energy ray crosslinkable adhesive composition to form a laminate of the resin film and the energy ray crosslinkable adhesive composition layer. Step 3: A step of irradiating the laminate of the resin film obtained in Step 2 and the energy-ray crosslinkable adhesive composition layer made of the energy-ray crosslinkable adhesive composition with energy rays to form a laminate of the substrate and the adhesive layer.

[0133] The description of steps 1 and 2 in the above manufacturing method is the same as that of steps 1 and 2 described in the first method for manufacturing adhesive sheets, and the preferred embodiments thereof are also the same.

[0134] (Step 3) In step 3, the timing of energy ray irradiation is not particularly limited and can be determined as appropriate considering the manufacturing method of the adhesive sheet, the desired physical properties, etc. For example, when one surface of the laminate is exposed, energy rays may be irradiated onto the laminate directly or through a support or release liner, or when the laminate has a support or release liner on one surface and a release liner on the other surface, energy rays may be irradiated through the support or release liner. However, when irradiating with energy rays through a support or release liner, it is preferable that the support or release liner has sufficient transparency to allow sufficient energy rays to be irradiated onto the resin film and the energy ray crosslinkable adhesive composition layer.

[0135] Furthermore, in step 3, it is preferable to irradiate the laminate with energy rays from the side facing the adhesive composition layer. In this case, even if the resin film is not transparent, energy is more easily irradiated to the surface of the resin film that is in contact with the adhesive composition layer through the adhesive composition layer, and component (B) in the resin film reacts to generate radicals on component (A) that serve as reaction initiation points. Similarly, if a release liner is attached to the adhesive composition layer, it is preferable to peel off the release liner to expose the surface of the adhesive composition layer, and then irradiate the exposed surface with energy rays. Alternatively, when irradiating with energy rays through a release liner, it is preferable to use a release liner with high energy ray permeability.

[0136] Furthermore, the energy beam irradiation of the laminate may be performed in a single step or in multiple steps.

[0137] Furthermore, irradiation conditions such as the type of energy ray, illuminance, and light intensity can be appropriately selected depending on the characteristics of the materials forming the resin film and the adhesive composition layer. For example, irradiation can be performed under conditions in which component (B) contained in each layer reacts to the energy ray and initiates the aforementioned reaction.

[0138] [Uses of adhesive sheets] The first adhesive sheet and the second adhesive sheet described above, which are aspects of the present invention, can be used for various applications. When using the first adhesive sheet, it can be used as the second adhesive sheet by irradiating it with energy rays immediately before or after attaching it to the substrate. However, from the viewpoint of making the effects of the present invention easier to achieve, it is preferable to first convert it into the second adhesive sheet and then attach it to the substrate. Specifically, examples include label applications; fixing or temporary fixing of various parts; surface protection applications; sealing material applications; decorative and display applications; and so on. Among these, label applications and applications for fixing or temporarily fixing various components are preferred.

[0139] Adhesive sheets for labeling may be directly attached to various products, or they may be attached to packaging films, packaging containers, etc., of various products. Examples of constituent materials for packaging films and packaging containers include olefin resins such as polypropylene and polyethylene; polyester resins such as polyethylene terephthalate (PET) and polylactic acid; glass, paper, metal; and the like. As an adhesive sheet for fixing or temporary fixing purposes, it is suitable for fixing or temporarily fixing, for example, electronic components, optical components, automobile parts, mechanical components, building components, decorative components, etc. [Examples]

[0140] The present invention will be specifically described by the following examples, but the present invention is not limited to these examples. The physical properties in each example were measured by the following methods.

[0141] [Weight average molecular weight (Mw)] The weight-average molecular weight (Mw) was measured using a gel permeation chromatograph under the following conditions and determined on a standard polystyrene basis. (Measuring equipment) • Measuring device: Product name "HLC-8320GPC", manufactured by Tosoh Corporation • Detector: Differential refractometer • Columns: One "TSK guard column super HH", two "TSK gel super HM-H" in series, and one "TSK gel super H2000" (all manufactured by Tosoh Corporation) are connected in this order from the sample inlet side. (Measurement conditions) Column temperature: 40°C • Developing solvent: tetrahydrofuran ·Flow rate: 1.0mL / min

[0142] [Thickness of each layer] The measurement was taken at 23°C using a constant-pressure thickness gauge manufactured by Teclock Corporation (model number: "PG-02J", compliant with standards: JIS K 6783, Z 1702, Z 1709).

[0143] Example 1 (Manufacturing of the first adhesive sheet) To obtain a sol for resin film formation, 100 parts by mass of polyvinyl chloride (product name "Ryuron Paste® 860", manufactured by Tosoh Corporation) with an average degree of polymerization of 1,600 was dispersed in ethylene glycol monobutyl ether as an organic solvent. This mixture contained 30 parts by mass of an adipic acid-based polyester plasticizer (product name "Adekasizer® P-200", manufactured by ADEKA Corporation) and 1 part by mass of a hydrogen abstraction type photoinitiator (4-methylbenzophenone, product name "SpeedCure® MBP", manufactured by Lambson Corporation). The organic solvent content in the obtained sol for resin film formation was 30% by mass. The sol of the resin film-forming composition obtained in this manner was applied by a knife coater to the release agent-treated surface of a polyethylene terephthalate release liner using a casting method, and a resin film with a thickness of 50 μm was produced by heating at 140°C for 1 minute and then at 190°C for 2 minutes. Next, using a slot die coater, an acrylic polymer having a benzophenone structure in its side chain (trade name "acResin® A204UV", manufactured by BASF, weight-average molecular weight (Mw) = 187,000) was melt-coated at 130°C as an adhesive composition (I) to a coating thickness of 25 μm, forming an energy-ray crosslinkable adhesive composition layer. A first adhesive sheet was obtained in which the resin film and the energy-ray crosslinkable adhesive composition layer were laminated in this order from the release liner side.

[0144] (Manufacturing of the second adhesive sheet) The energy-crosslinkable adhesive composition layer of the first adhesive sheet obtained above is exposed from the exposed side using a high-pressure mercury lamp with an integrated light intensity of 100 mJ / cm² in the UV-C region. 2 The material was irradiated with ultraviolet light under the specified conditions. This irradiation produced a laminate of a substrate formed from the resin film of the first adhesive sheet and an adhesive layer formed from the energy-ray crosslinkable adhesive composition layer. Next, a release liner was laminated onto the exposed surface of the adhesive layer, and then the release liner on the substrate was peeled off and removed, thereby obtaining a second adhesive sheet in which the substrate and the adhesive layer were laminated in this order, and the surface of the adhesive layer was further protected by the release liner.

[0145] Examples 2-4 In each of the two examples, the first and second adhesive sheets were prepared in the same manner as in Example 1, except that the substrate used was modified in which the content of the hydrogen abstraction type photoinitiator in the resin film forming composition was changed to the content shown in Table 1 below.

[0146] Example 5 (Manufacturing of energy ray crosslinkable adhesive compositions) 100 parts by mass of an acrylic acid ester copolymer (n-butyl acrylate (BA) / acrylic acid (AA) = 90 / 10, weight-average molecular weight (Mw) = 250,000) and 5 parts by mass of a hydrogen abstraction type photoinitiator (4-methylbenzophenone, trade name "SpeedCure® MBP", manufactured by Lambson) were kneaded at 130°C for 20 minutes under nitrogen purging using a heated kneader to obtain an energy ray crosslinkable adhesive composition (II). (Manufacturing of the first and second adhesive sheets) A first adhesive sheet and a second adhesive sheet were prepared in the same manner as described in Example 1, except that the energy ray crosslinkable adhesive composition (II) was used instead of an acrylic polymer having a benzophenone structure in its side chain.

[0147] Example 6 (Manufacturing of the first adhesive sheet) A resin film was prepared using the same method as described in Example 1. Next, a solution of the energy-ray crosslinkable adhesive composition dissolved in ethyl acetate (60% by mass of organic solvent content) was applied to the release agent treated surface of the release liner using a roll knife coater so that the coating thickness after drying was 25 μm, and the solution was dried at 90°C for 1 minute to form an energy-ray crosslinkable adhesive composition layer. The energy-ray crosslinkable adhesive composition used was a mixture of 100 parts by mass of an acrylic acid ester copolymer (n-butyl acrylate (BA) / acrylic acid (AA) = 90 / 10, weight-average molecular weight (Mw) = 700,000) and 5 parts by mass of a hydrogen abstraction type photoinitiator (4-methylbenzophenone, trade name "SpeedCure® MBP", manufactured by Lambson). Next, the dried energy-ray crosslinkable adhesive composition layer was laminated onto the surface of the resin film prepared by the method described above, on the side opposite to the side where the support was provided, thereby obtaining a first adhesive sheet in which the resin film, the energy-ray crosslinkable adhesive composition layer, and the release liner were laminated in that order from the release liner side on the resin film. (Manufacturing of the second adhesive sheet) The release liner is removed from the energy-crosslinkable adhesive composition layer of the first adhesive sheet obtained above, and from the exposed side, a high-pressure mercury lamp is used to apply an integrated light intensity of 100 mJ / cm² in the UV-C region. 2 A laminate consisting of a substrate and an adhesive layer was formed by irradiating it with ultraviolet light under these conditions. Next, a release liner was laminated onto the exposed surface of the adhesive layer, and then the release liner on the substrate was peeled off and removed, thereby obtaining a second adhesive sheet in which the substrate and the adhesive layer were laminated in this order, and the surface of the adhesive layer was further protected by the release liner.

[0148] Comparative Example 1 The first and second adhesive sheets were prepared in the same manner as in Example 1, except that a hydrogen abstraction type photoinitiator was not used in the preparation of the resin film of Example 1, and a resin film that did not contain a hydrogen abstraction type photoinitiator was used.

[0149] Comparative Example 2 The first and second adhesive sheets were prepared in the same manner as in Example 6, except that in the preparation of the adhesive layer in Example 5, a hydrogen abstraction type photoinitiator was not used, and an adhesive layer formed solely from the acrylic acid ester copolymer was used.

[0150] Comparative Example 3 After preparing a resin film using the same method as in Example 1, the exposed surface of the resin film is exposed to a high-pressure mercury lamp with an integrated UV-C light intensity of 100 mJ / cm². 2 Ultraviolet light was irradiated under these conditions. Next, an acrylic polymer having a benzophenone structure in its side chain (product name "acResin® A204UV", manufactured by BASF, weight-average molecular weight (Mw) = 187,000) is melt-coated onto the release agent treated surface of the release liner using a slot die coater at 130°C to a coating thickness of 25 μm, forming an energy-ray crosslinkable adhesive composition layer. Then, the exposed surface of the energy-ray crosslinkable adhesive composition layer is exposed to a high-pressure mercury lamp with an integrated UV-C light intensity of 100 mJ / cm². 2 Ultraviolet light was irradiated under these conditions. The energy-crosslinkable adhesive composition layer after UV irradiation was laminated onto the exposed surface of the resin film after UV irradiation to produce an adhesive sheet.

[0151] [Peel test] The second adhesive sheets produced in Examples 1-6 and Comparative Examples 1-2, as well as the adhesive sheet produced in Comparative Example 3, were cut to 25mm x 50mm in a 23°C, 50%RH (relative humidity) environment to prepare two test pieces for each. The release liner was removed from each test piece, and the exposed adhesive layer was attached to a substrate (stainless steel plate). Then, the test specimens attached to the substrate were left to stand for 7 days in an environment of 23°C and 50% RH (relative humidity). After that, one of the test specimens was peeled off from the substrate by hand at a speed of approximately 300 mm / min in a 180° direction (low-speed peeling), and the other specimen was peeled off by hand at a speed of approximately 30 m / min in a 180° direction (high-speed peeling). Furthermore, the condition of each layer of the test specimen after delamination was visually observed and confirmed according to the following criteria. The results obtained are shown in Table 1 below. No contamination: The adhesive layer peels off at the interface with the substrate, leaving no adhesive residue on the substrate and exhibiting excellent peelability. Transfer: Peeling occurred at the interface between the substrate and the adhesive layer, and residue of the adhesive layer was confirmed on the adherend. Cohesive failure: The adhesive layer broke down, and residue of the adhesive layer was confirmed on the adherend. Substrate failure: The substrate failed, and adhesive residue was found on the adherend.

[0152] [Table 1]

[0153] The abbreviations in Table 1 represent the following components, as described above. • PVC: Polyvinyl chloride with an average degree of polymerization of 1,600 (product name "Ryuron Paste (registered trademark) 860", manufactured by Tosoh Corporation) • Plasticizer: Adipic acid-based polyester plasticizer (product name "ADEKA Sizer (registered trademark) P-200", manufactured by ADEKA Corporation) • Photoinitiator: Hydrogen abstraction type photoinitiator (4-methylbenzophenone, trade name "SpeedCure® MBP", manufactured by Lambson) • A204UV: An acrylic polymer having a benzophenone structure in its side chain; trade name "acResin(registered trademark) A204UV" (manufactured by BASF). P(BA / AA)-1: Acrylic acid ester copolymer (n-butyl acrylate (BA) / acrylic acid (AA) = 90 / 10, weight-average molecular weight (Mw) = 250,000) P(BA / AA)-2: Acrylic acid ester copolymer (n-butyl acrylate (BA) / acrylic acid (AA) = 90 / 10, weight-average molecular weight (Mw) = 700,000)

[0154] Table 1 shows that the second adhesive sheets obtained in Examples 1 to 6 exhibit excellent adhesion to the substrate, and under low-speed peeling conditions, they can be peeled off the substrate without contaminating it after being applied to it. Furthermore, it was confirmed that the second adhesive sheets obtained in Examples 1-3 and Examples 5 and 6, after energy ray irradiation, in which the hydrogen extraction type photoinitiator content in the resin film before ultraviolet irradiation was 10 parts by mass or less per 100 parts by mass of polyvinyl chloride, could be peeled off without contaminating the adherend after being applied to the adherend, even under high-speed peeling conditions. The second adhesive sheets obtained in Examples 1 to 6 are thought to have improved adhesion at the interface between the substrate and the adhesive layer because, during ultraviolet irradiation when the second adhesive sheets are made, radicals are generated not only in the energy-ray crosslinkable adhesive composition layer, but also when the hydrogen abstraction type photoinitiator in the resin film reacts with polyvinyl chloride to generate radicals, and crosslinks are formed between the resin in the resin film and the resin in the energy-ray crosslinkable adhesive composition layer. On the other hand, the second adhesive sheet obtained in Comparative Example 1 did not contain a hydrogen extraction type photoinitiator in the resin film of the first adhesive sheet. Therefore, when the second adhesive sheet was peeled off under low-speed peeling conditions after UV irradiation, it was confirmed that peeling occurred at the interface between the substrate and the adhesive layer, resulting in "transfer" where the adhesive layer remained on the adherend. Furthermore, it was confirmed that the adhesive sheet obtained in Comparative Example 3, which was manufactured by laminating each layer after irradiating each layer with ultraviolet light, rather than laminating the resin film and the energy-ray crosslinkable adhesive composition layer, resulted in "transfer" occurring, similar to Comparative Example 1. Furthermore, it was confirmed that the second adhesive sheet obtained in Comparative Example 2, because its adhesive layer was not formed from an energy-ray crosslinkable adhesive composition layer, experienced "cohesive failure" even under low-speed peeling conditions, resulting in the adhesive layer being destroyed and remaining on the adherend.

[0155] As described above, the second adhesive sheets obtained in Examples 1 to 6 were confirmed to be adhesive sheets with excellent adhesion to the substrate and that can be peeled off without contaminating the adherend. Furthermore, these effects can be achieved even when polyvinyl chloride is used as the substrate. For this reason, the resin film, the first adhesive sheet, and the second adhesive sheet according to each embodiment of the present invention, as well as the methods for manufacturing them, can be suitably used even when using low-polarity substrates such as polyvinyl chloride or polyolefin. [Explanation of Symbols]

[0156] 1. Energy ray crosslinkable adhesive composition layer 2. Resin film 3, 3a, 3b Release Liner 4. Adhesive layer 5 Base material 6 Support 10a, 20a, 30a First adhesive sheet 10b, 20b, 30b Second adhesive sheet

Claims

1. An adhesive sheet comprising a laminate of a substrate and an adhesive layer, The substrate is formed by irradiating a resin film containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator with energy rays, wherein component (A) is a polymer from which hydrogen can be abstracted by component (B), The adhesive layer is formed by irradiating an energy ray crosslinkable adhesive composition layer, which is made of an energy ray crosslinkable adhesive composition, with energy rays. The laminate of the substrate and the adhesive layer is an adhesive sheet formed by irradiating the laminate of the resin film and the energy-ray crosslinkable adhesive composition layer with energy rays.

2. The adhesive sheet according to claim 1, wherein component (A) is at least one selected from the group consisting of polyvinyl chloride resin, polyolefin, acrylic resin, and styrene resin.

3. The adhesive sheet according to claim 1 or 2, wherein the content of component (B) in the resin film is 10 parts by mass or less per 100 parts by mass of component (A).

4. The adhesive sheet according to any one of claims 1 to 3, wherein the content of component (A) in the resin film is 50% by mass or more of the total mass of the components constituting the resin film.

5. The adhesive sheet according to any one of claims 1 to 4, wherein the energy-ray crosslinkable adhesive composition is (I) an adhesive composition containing (C) an acrylic polymer having energy-ray crosslinkability, or (II) an acrylic polymer other than component (C) and (B) a hydrogen abstraction type photoinitiator.

6. Component (C) in the adhesive composition (I) is an acrylic polymer having energy-reactive groups that react upon irradiation with (C1) energy rays and contribute to the formation of a crosslinked structure, The adhesive sheet according to claim 5, wherein component (C1) is an acrylic polymer having a benzophenone structure in its side chain.

7. The adhesive sheet according to claim 5 or 6, wherein the content of component (C) is 50 to 100% by mass of the total amount of the adhesive composition (I).

8. The adhesive sheet according to claim 5, wherein the content of component (D) is 50% by mass or more of the total amount of the adhesive composition (II) (100% by mass).

9. A method for manufacturing an adhesive sheet according to any one of claims 1 to 8, comprising the following steps 1 to 3 in this order. Step 1: A step of forming a resin film containing (A) a polymer and (B) a hydrogen abstraction type photoinitiator. Step 2: A step of laminating the resin film obtained in Step 1 with an energy ray crosslinkable adhesive composition layer made of an energy ray crosslinkable adhesive composition to form a laminate of the resin film and the energy ray crosslinkable adhesive composition layer. Step 3: A step of irradiating the laminate of the resin film obtained in Step 2 and the energy-ray crosslinkable adhesive composition layer made of the energy-ray crosslinkable adhesive composition with energy rays to form a laminate of the substrate and the adhesive layer.

10. An adhesive sheet comprising a laminate of a resin film and an energy ray crosslinkable adhesive composition layer consisting of an energy ray crosslinkable adhesive composition containing polymer components, The resin film contains (A) a polymer and (B) a hydrogen abstraction type photoinitiator, wherein component (A) is a polymer capable of hydrogen abstraction by component (B). An adhesive sheet in which the polymer (A) and the polymer component in the energy-ray crosslinkable adhesive composition layer can be crosslinked by energy ray irradiation.

11. A resin film comprising (A) a polymer and (B) a hydrogen abstraction type photoinitiator, wherein component (A) is a polymer capable of hydrogen abstraction by component (B), A resin film for laminating an energy-ray crosslinkable adhesive composition layer comprising an energy-ray crosslinkable adhesive composition containing a polymer component, wherein the polymer (A) and the polymer component in the energy-ray crosslinkable adhesive composition layer are crosslinkable by energy irradiation.

Images