Adhesive sheets, unit panels and video wall displays

Abstract

The technical problem of the present invention is to provide an adhesive sheet, a unit panel, and a splicing display with good laser cutting processability. The adhesive sheet (1A) is an adhesive sheet (1A) used to manufacture a unit panel (2A) constituting a splicing display. It has a first adhesive layer (12), a second adhesive layer (13), and a core material (14) disposed between the first adhesive layer (12) and the second adhesive layer (13). When a pressure of 10 kPa is applied to the adhesive laminate (11) composed of the first adhesive layer (12), the core material (14), and the second adhesive layer (13) at a temperature of 23°C and a frequency of 1 Hz for 600 seconds using the torsion shearing method according to JIS K7244-6, the strain is less than 120%.

Description

Technical Field

[0001] The present invention relates to a video wall display, a unit panel constituting the video wall display, and an adhesive sheet for manufacturing the unit panel. Background Technology

[0002] In recent years, with the increasing demand for higher resolution displays such as 4K and 8K, the need for larger screen displays has been growing. Furthermore, the use of large-screen displays in digital signage, such as advertising displays in outdoor locations and public facilities, is also being promoted. However, manufacturing large-screen displays in a single step leads to lower yield rates and higher manufacturing costs. To address this, and to manufacture large-screen displays at a lower cost, a splicing display method has been proposed, which connects multiple unit panels to form a tiled display (Patent Document 1, etc.).

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2007-192977 Summary of the Invention

[0004] (a) Technical problems to be solved However, when multiple unit panels are connected to form a spliced ​​structure as described above, uneven brightness can easily occur in the gaps between the panels, leading to a decrease in image quality. This problem becomes particularly pronounced in displays using high-brightness Mini-LEDs or Micro-LEDs, which are seen as next-generation displays.

[0005] Therefore, in order to eliminate gaps between panels, laser cutting can be considered to shape the ends of the unit panels into flat surfaces. However, when laser cutting the ends of unit panels manufactured using conventional adhesive layers, adhesive seepage from the end faces can occur.

[0006] The present invention was implemented in view of the above-mentioned actual situation, and its purpose is to provide an adhesive sheet, a unit panel and a splicing display with good laser cutting processability.

[0007] (II) Technical Solution To achieve the above objectives, firstly, the present invention provides an adhesive sheet for manufacturing a unit panel constituting a splicing display. The adhesive sheet is characterized by comprising: a first adhesive layer, a second adhesive layer, and a core material disposed between the first adhesive layer and the second adhesive layer. When a pressure of 10 kPa is applied to the adhesive laminate composed of the first adhesive layer, the core material, and the second adhesive layer at a temperature of 23°C and a frequency of 1 Hz for 600 seconds using the torsional shearing method according to JIS K7244-6, the strain is 120% or less (Invention 1).

[0008] Second, the present invention provides an adhesive sheet for manufacturing a unit panel constituting a splicing display, characterized in that it has an adhesive layer, and the strain of the adhesive layer when subjected to a pressure of 10 kPa for 600 seconds at a temperature of 23°C and a frequency of 1 Hz by the torsion shear method according to JIS K7244-6 is less than 120% (Invention 2).

[0009] The adhesive laminate and adhesive layer in the above-mentioned inventions (Inventions 1 and 2) have a specified hardness by satisfying the aforementioned physical properties. As a result, when the end of a unit panel having an adhesive laminate or adhesive layer is laser-cut to form a flat end face, adhesive seepage from that end face can be suppressed.

[0010] In the above inventions (Inventions 1 and 2), it is preferred that the gel content of the adhesive constituting the adhesive layer is 20% or more and 99% or less (Invention 3).

[0011] Third, the present invention provides an adhesive sheet for manufacturing a unit panel constituting a splicing display, characterized in that it comprises: a first adhesive layer, a second adhesive layer, and a core material disposed between the first adhesive layer and the second adhesive layer, wherein the strain is less than 120% when a pressure of 10 kPa is applied to the adhesive laminate composed of the first adhesive layer, the core material and the second adhesive layer at a temperature of 23°C and a frequency of 1 Hz for 600 seconds using the torsion shear method according to JIS K7244-6, and the adhesion of the first adhesive layer and the second adhesive layer to soda-lime glass is 5 N / 25 mm or more (Invention 4).

[0012] Fourth, the present invention provides an adhesive sheet for manufacturing a unit panel constituting a splicing display, characterized in that it comprises: a first adhesive layer, a second adhesive layer, and a core material disposed between the first adhesive layer and the second adhesive layer, wherein the gel fraction of the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer is 30% or more and 99% or less, and the adhesion force of the first adhesive layer and the second adhesive layer to soda-lime glass is 5N / 25mm or more (Invention 5).

[0013] The adhesive laminate in the above-described invention (Invention 4) possesses a specified hardness and adhesive strength by satisfying the aforementioned physical properties. Furthermore, the adhesive laminate in the above-described invention (Invention 5) possesses a specified cohesive strength and adhesive strength by satisfying the aforementioned physical properties. As a result, when the end face of a unit panel having the above-described adhesive laminate is laser-cut to form a flat surface, adhesive seepage from the end face can be suppressed, and lifting and peeling at the interface between the adhesive laminate and its adhered object can be suppressed.

[0014] In the above invention (Invention 4), it is preferable that the gel fractions of the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are 30% or more and 99% or less (Invention 6).

[0015] In the above inventions (Inventions 1, 3 to 6), it is preferred that the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are acrylic adhesives (Invention 7).

[0016] In the above inventions (Inventions 2 and 3), it is preferred that the adhesive constituting the adhesive layer is an adhesive containing epoxy resin or a polyester adhesive (Invention 8).

[0017] In the above inventions (Inventions 1, 3 to 7), preferably, the thickness of the first adhesive layer and the second adhesive layer is 1 μm or more and 100 μm or less, and the thickness of the core material is 1 μm or more and 300 μm or less (Invention 9).

[0018] In the above inventions (Inventions 2, 3, 8), it is preferred that the thickness of the adhesive layer is 1 μm or more and 100 μm or less (Invention 10).

[0019] In the above inventions (Inventions 1, 3 to 7, 9), preferably, the core material is made of a plastic film (Invention 11).

[0020] In the above inventions (Inventions 1 to 11), preferably, the adhesive sheet has two release tabs that protect the adhesive surface of the adhesive layer, one of the release tabs being located on the outermost layer of one side of the adhesive sheet, and the other release tab being located on the outermost layer of the other side of the adhesive sheet (Invention 12).

[0021] Fifth, the present invention provides a unit panel, which is a unit panel constituting a splicing display, characterized in that the unit panel includes an adhesive laminate (invention 13) composed of the first adhesive layer, the core material and the second adhesive layer in the adhesive sheet (inventions 1, 3 to 7, 9, 11, 12).

[0022] Sixth, the present invention provides a unit panel, which is a unit panel constituting a splicing display, characterized in that the unit panel has an adhesive layer (invention 14) of the adhesive sheets (inventions 2, 3, 8, 10, 12).

[0023] In the above inventions (Inventions 13 and 14), preferably, the end face of the unit panel is formed by laser cutting (Invention 15).

[0024] In the above inventions (Inventions 13, 15), preferably: the unit panel has a surface substrate and a light-emitting substrate, and the unit panel is formed by bonding the surface substrate or a laminate having the surface substrate and the light-emitting substrate or a laminate having the light-emitting substrate through the adhesive laminate (Invention 16).

[0025] In the above inventions (Inventions 14 and 15), preferably, the unit panel has a surface substrate and a light-emitting substrate, and the unit panel is formed by bonding the surface substrate or a laminate having the surface substrate and the light-emitting substrate or a laminate having the light-emitting substrate through the adhesive layer (Invention 17).

[0026] In the above inventions (Inventions 13-17), preferably, the light-emitting body of the light-emitting substrate is a sub-millimeter light-emitting diode or a micro light-emitting diode (Invention 18).

[0027] Seventh, the present invention provides a splicing display formed by connecting multiple of the aforementioned unit panels (Inventions 13-18) (Invention 19).

[0028] (III) Beneficial Effects The adhesive sheet, unit panel, and splicing display of the present invention have good laser cutting processability. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of the adhesive sheet according to the first embodiment of the present invention.

[0030] Figure 2 This is a cross-sectional view of the adhesive sheet according to the second embodiment of the present invention.

[0031] Figure 3 This is a cross-sectional view of a unit panel according to the first embodiment of the present invention.

[0032] Figure 4 This is a cross-sectional view of a unit panel according to a second embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures 1A, 1B: Adhesive sheets; 11: Adhesive laminate; 12: First adhesive layer; 12S: Adhesive surface of the first adhesive layer; 13: Second adhesive layer; 13S: Adhesive surface of the second adhesive layer; 14: Core material; 15: Adhesive layer; 16a, 16b: Release sheets; 2A, 2B: Unit panels; 21: Light-emitting substrate; 22: Surface substrate. Detailed Implementation

[0034] The following describes the embodiments of the present invention.

[0035] [Adhesive sheet] The adhesive sheet of the present invention is used to manufacture unit panels constituting a video wall display. An example of the adhesive sheet of the first embodiment of the present invention is shown below. Figure 1 An example of the adhesive sheet according to the second embodiment of the present invention is shown below. Figure 2 .

[0036] like Figure 1 As shown, the adhesive sheet 1A of the first embodiment of the present invention comprises an adhesive laminate 11 consisting of a first adhesive layer 12, a second adhesive layer 13, and a core material 14 disposed between the first adhesive layer 12 and the second adhesive layer 13. In this embodiment, a release sheet 16a is laminated on the adhesive surface 12S of the first adhesive layer 12 in contact with the release surface of the release sheet 16a, and a release sheet 16b is laminated on the adhesive surface 13S of the second adhesive layer 13 in contact with the release surface of the release sheet 16b.

[0037] In addition, such as Figure 2 As shown, the adhesive sheet 1B of the second embodiment of the present invention includes an adhesive layer 15. In this embodiment, the adhesive layer 15 is a single layer and is held by the two release sheets 16a and 16b in such a way that it contacts the release surfaces of the two release sheets 16a and 16b.

[0038] In addition, the adhesive surface of the adhesive layer in this specification refers to the surface of the adhesive layer that contacts and adheres to the object to be bonded. Furthermore, the peeling surface of the release liner in this specification refers to the peelable surface of the release liner, including either the surface that has undergone a peeling treatment or the surface that exhibits peelability even without a peeling treatment.

[0039] The aforementioned release tabs 16a and 16b protect the first adhesive layer 12, the second adhesive layer 13, or the adhesive layer 15 until adhesive sheets 1A and 1B are used, at which point they are peeled off. In this embodiment, one or both of the release tabs 16a and 16b are not necessarily required for adhesive sheets 1A and 1B.

[0040] As a first approach, by applying a pressure of 10 kPa for 600 seconds to the adhesive laminate 11 consisting of the first adhesive layer 12, the core material 14, and the second adhesive layer 13 in adhesive sheet 1A, and the adhesive layer 15 of adhesive sheet 1B (or the adhesive laminate / adhesive layer cured by active energy radiation when the adhesive layer is ray-cured) at a temperature of 23°C and a frequency of 1 Hz according to the torsional shear method of JIS K7244-6, the strain (creep strain) is preferably 120% or less. Details of the creep strain measurement method in this specification are shown in the test examples described later.

[0041] The adhesive laminate 11 and adhesive layer 15 possess a specified hardness by satisfying the aforementioned physical properties. As a result, even when the end face of a unit panel having the adhesive laminate 11 or adhesive layer 15 is laser-cut to form a flat surface, adhesive leakage from that end face can be suppressed. Thus, the laser-cutting processability of the adhesive sheets 1A and 1B in this embodiment is excellent. Furthermore, in a splicing display formed by connecting multiple unit panels laser-cut in the above manner, there are almost no gaps between the unit panels, thereby achieving uniform brightness and improved image quality.

[0042] As a second approach, when the adhesive laminate 11 (or the adhesive laminate cured by active energy radiation if the adhesive layer is ray-cured) consisting of a first adhesive layer 12, a core material 14, and a second adhesive layer 13 in the adhesive sheet 1 is subjected to a pressure of 10 kPa for 600 seconds at a temperature of 23°C and a frequency of 1 Hz according to the torsional shear method of JIS K7244-6, the strain (creep strain) is preferably 120% or less. Alternatively, the gel fraction of the adhesive in the first adhesive layer 12 and the adhesive in the second adhesive layer 13 in the adhesive sheet 1 is preferably 30% or more and 99% or less, respectively. Furthermore, the adhesion force of the first adhesive layer 12 and the second adhesive layer 13 to the soda-lime glass is preferably 5 N / 25 mm or more, respectively. In addition, it is preferable that the adhesive sheet 1 satisfies either the above-mentioned creep strain and gel fraction, but it is more preferable that both are satisfied.

[0043] Here, the adhesive force referred to in this specification is the adhesive force measured primarily by the 180-degree peel method according to JIS Z0237:2022. This adhesive force is determined by preparing a test sample 25 mm wide and 100 mm long, attaching it to the substrate, applying pressure at 0.5 MPa and 50°C for 20 minutes, then placing it under normal pressure, 23°C, and 50% relative humidity for 24 hours, and finally peeling it at a rate of 300 mm / min. Additionally, in this specification, "relative humidity α%" is sometimes expressed as "α%RH" (RH; Relative humidity).

[0044] The adhesive laminate 11 has a specified hardness by satisfying the aforementioned creep strain. Furthermore, the adhesive laminate 11 has a specified cohesive force by satisfying the aforementioned gel fraction. As a result, when the end face of the unit panel having the adhesive laminate 11 is laser-cut to form a flat surface, adhesive leakage from that end face can be suppressed. Thus, the adhesive sheet 1 of this embodiment exhibits excellent laser-cutting processability. Furthermore, by satisfying the aforementioned adhesive force, the adhesive laminate 11 is less prone to lifting or peeling at the interface between the first adhesive layer 12 and the adherend (e.g., the light-emitting substrate) and the interface between the second adhesive layer 13 and the adherend (e.g., the surface substrate) during laser cutting, resulting in excellent adhesion.

[0045] A splicing display formed by connecting multiple unit panels processed by laser cutting in the above manner has almost no gaps between the unit panels, thereby achieving uniform brightness and higher image quality.

[0046] In the first and second embodiments, from the above perspective, the creep strain of the adhesive laminate 11 and the adhesive layer 15 is more preferably 100% or less, particularly preferably 90% or less, further preferably 80% or less, and most preferably 70% or less. Considering adhesion, the lower limit of the above creep strain is preferably 0.1% or more, more preferably 1% or more, particularly preferably 4% or more, and further preferably 8% or more.

[0047] The gel fraction of the adhesive constituting adhesive layers 12, 13, and 15 in the first embodiment is preferably 20-99%, more preferably 30-90%, particularly preferably 40-80%, further preferably 44-75%, and most preferably 48-70%, especially preferably 52-65%. This makes it easier to meet the aforementioned creep strain while maintaining the specified cohesive force, resulting in superior laser cutting processability. The method for determining the gel fraction in this specification is shown in the experimental examples described later.

[0048] From the perspective of the laser cutting processability mentioned above, the gel fraction of the adhesive constituting the adhesive layers 12 and 13 in the second embodiment is more preferably 35-90%, particularly preferably 40-80%, further preferably 44-75%, and preferably 48-70%, especially preferably 52-65%.

[0049] In the first and second embodiments, when the adhesive constituting the adhesive layers 12, 13, and 15 is curable by active energy radiation, the gel fraction after curing by active energy radiation is preferably 30-99%, more preferably 40-94%, particularly preferably 50-90%, further preferably 60-86%, and most preferably 70-82%. This makes it easier to meet the aforementioned creep strain while maintaining the specified cohesive force, resulting in superior laser cutting processability. Furthermore, it provides suitable adhesion.

[0050] In the first embodiment, the adhesion strength is preferably 1N / 25mm or more, more preferably 5N / 25mm or more, particularly preferably 10N / 25mm or more, further preferably 15N / 25mm or more, and most preferably 20N / 25mm or more, especially preferably 25N / 25mm or more. Therefore, during laser cutting, it is less likely for the first adhesive layer 12 to lift or peel off at the interface with the adherend (e.g., the light-emitting substrate) and the second adhesive layer 13 to fall off at the interface with the adherend (e.g., the surface substrate), resulting in excellent adhesion.

[0051] In the second embodiment, from the perspective of the aforementioned adhesion, the adhesion of the first adhesive layer 12 and the second adhesive layer 13 to the soda-lime glass is more preferably 10N / 25mm or more, particularly preferably 15N / 25mm or more, further preferably 20N / 25mm or more, and preferably 25N / 25mm or more.

[0052] In both the first and second embodiments, the upper limit of the aforementioned adhesive force is preferably 100 N / 25 mm or less, more preferably 75 N / 25 mm or less, particularly preferably 50 N / 25 mm or less, and most preferably 40 N / 25 mm or less. This provides good reoperability, allowing the adhered material to be reused in the event of an adhesion error.

[0053] In the first and second embodiments, when the first adhesive layer 12 or the second adhesive layer 13 is curable by active energy radiation, the adhesion strength after the first adhesive layer 12S of the adhesive sheet 1 is attached to the soda-lime glass and the first adhesive layer 12 is cured by active energy radiation (adhesion strength after active energy radiation curing), or the adhesion strength after the second adhesive layer 13S of the adhesive sheet 1 is attached to the soda-lime glass and the second adhesive layer 13 is cured by active energy radiation (adhesion strength after active energy radiation curing), is preferably 5N / 25mm or more, more preferably 15N / 25mm or more, particularly preferably 25N / 25mm or more, further preferably 30N / 25mm or more, and preferably 35N / 25mm or more. Therefore, during laser cutting, it is less likely for the first adhesive layer 12 after being cured by active energy rays to lift or peel off at the interface with the adhered object (e.g., the light-emitting substrate) or the second adhesive layer 13 after being cured by active energy rays to lift or peel off at the interface with the adhered object (e.g., the surface substrate), resulting in better adhesion.

[0054] Furthermore, the upper limit of the adhesion force after curing by the aforementioned active energy rays is preferably 100 N / 25 mm or less, more preferably 80 N / 25 mm or less, particularly preferably 60 N / 25 mm or less, and most preferably 50 N / 25 mm or less. This provides good reworkability, allowing the adhered material to be reused in the event of an adhesion error.

[0055] 1. Adhesive sheet of the first embodiment 1-1. Constituent Elements 1-1-1. Adhesive layer For the adhesives constituting the first adhesive layer 12 of the adhesive sheet 1A in the first embodiment and the second adhesive layer 13, the adhesive laminate 11 including the core material 14 only needs to satisfy the aforementioned creep strain or gel fraction. Examples of such adhesives include acrylic adhesives, polyester adhesives, polyurethane adhesives, rubber adhesives, and silicone adhesives, among which acrylic adhesives that readily satisfy the aforementioned creep strain and gel fraction are preferred.

[0056] As an acrylic adhesive, a cross-linking type is preferred, and a thermally cross-linking type is even more preferred. Furthermore, the acrylic adhesive used in this embodiment can be either non-reactive energy ray curable or reactive energy ray curable. Additionally, from the perspective of SDGs, materials constituting this adhesive can be materials with high biomass content, recyclable or reusable materials, or materials that have already been recycled or reused.

[0057] Specifically, the adhesive in this embodiment is preferably formed by crosslinking an adhesive composition (hereinafter sometimes referred to as "adhesive composition P") containing a (meth)acrylate polymer (A) and a crosslinking agent (B). The adhesive obtained by crosslinking adhesive composition P readily satisfies the aforementioned physical properties. Furthermore, in this specification, (meth)acrylate refers to acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, "polymer" also includes the concept of "copolymer".

[0058] (1) Components of adhesive composition P (1-1) (Meth)acrylate polymer (A) The (meth)acrylate polymer (A) in this embodiment preferably contains a monomer with reactive groups as the monomer unit constituting the polymer, the monomer having reactive groups within the molecule that react with the crosslinking agent (B). By reacting the reactive groups from the monomer with the crosslinking agent (B), a crosslinked structure (three-dimensional network structure) can be formed, and an adhesive with the desired cohesive strength can be obtained.

[0059] As monomers containing reactive groups, preferred examples include monomers with intramolecular hydroxyl groups (hydroxyl-containing monomers) and monomers with intramolecular carboxyl groups (carboxyl-containing monomers). Among these, monomers containing hydroxyl groups or carboxyl groups that exhibit excellent reactivity with the crosslinking agent (B) are preferred, and monomers containing hydroxyl groups are particularly preferred.

[0060] Examples of hydroxyl-containing monomers include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxybutyl methacrylate, and 4-hydroxybutyl methacrylate, among other hydroxyalkyl methacrylates. From the perspective of reactivity with the crosslinking agent (B) and copolymerization with other monomers, hydroxyalkyl methacrylates having 1 to 4 carbon atoms are preferred. Specifically, 2-hydroxyethyl methacrylate and 4-hydroxybutyl methacrylate are preferred examples, with 2-hydroxyethyl acrylate or 4-hydroxybutyl acrylate being particularly preferred. These hydroxyl-containing monomers can be used alone or in combination of two or more.

[0061] The (meth)acrylate polymer (A) preferably contains 1-40% by mass, more preferably 6-36% by mass, particularly preferably 12-32% by mass, even more preferably 18-28% by mass, and preferably contains 20-26% by mass of a monomer containing a reactive group as the monomer unit constituting the polymer. Thus, the resulting adhesive has high cohesive strength and readily meets the aforementioned creep strain and gel fraction requirements.

[0062] Furthermore, the (meth)acrylate polymer (A) preferably does not contain carboxyl-containing monomers as monomer units constituting the polymer. Since carboxyl groups are acidic components, by not containing carboxyl-containing monomers, even if substances that cause adverse effects due to acid are present in the adherend of the adhesive, such adverse effects can be suppressed. However, it is also permissible to contain a specified amount of carboxyl-containing monomers to the extent that such adverse effects are not caused. Specifically, it is permissible for the (meth)acrylate polymer (A) to contain carboxyl-containing monomers as monomer units in an amount of 0.1% by mass or less, preferably 0.01% by mass or less, and more preferably 0.001% by mass or less.

[0063] The (meth)acrylate polymer (A) preferably contains alkyl (meth)acrylate as a monomer unit constituting the polymer. This results in good adhesion. The alkyl group can be linear or branched.

[0064] From the perspective of adhesion, alkyl methacrylates with 1 to 20 carbon atoms in the alkyl group are preferred. Examples of alkyl methacrylates with 1 to 20 carbon atoms in the alkyl group include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, and octadecyl methacrylate. Among these, from the perspective of further improving adhesion and easily satisfying the aforementioned physical properties, alkyl methacrylates with 4 to 8 carbon atoms in the alkyl group are preferred, particularly n-butyl methacrylate, 2-ethylhexyl methacrylate, or isooctyl methacrylate, and even more preferably n-butyl acrylate, 2-ethylhexyl acrylate, or isooctyl methacrylate. In addition, these alkyl (meth)acrylates can be used alone or in combination of two or more.

[0065] The (meth)acrylate polymer (A) preferably contains 30-99% by mass, more preferably 40-90% by mass, particularly preferably 45-80% by mass, and even more preferably 50-70% by mass of alkyl (meth)acrylate as the monomer unit constituting the polymer. Thus, the adhesive formed from the adhesive composition containing the (meth)acrylate polymer (A) can exhibit suitable adhesive properties, while simultaneously allowing the introduction of other monomer components, such as monomers containing reactive functional groups, into the (meth)acrylate polymer (A) in appropriate amounts, easily satisfying the aforementioned physical properties.

[0066] The (meth)acrylate polymer (A) preferably contains monomers with an intramolecular alicyclic structure (containing alicyclic monomers) as monomer units constituting the polymer. This makes it easier to satisfy the aforementioned physical properties while also tending to achieve good adhesion.

[0067] The alicyclic carbon rings in the monomer containing the alicyclic structure can be saturated or partially unsaturated. Furthermore, the alicyclic structure can be a monocyclic alicyclic structure or a multicyclic alicyclic structure such as a bicyclic or tricyclic structure (polycyclic structure). From the perspective of ensuring appropriate spacing between the resulting (meth)acrylate polymers (A), the aforementioned alicyclic structure is preferably a polycyclic structure. Further, considering the compatibility of the (meth)acrylate polymer (A) with other components, the aforementioned polycyclic structure is particularly preferably bicyclic to tetracyclic. Moreover, from the same perspective as above, the number of carbon atoms in the alicyclic structure (referring to the total number of carbon atoms in the ring-forming portion, or the total number of carbon atoms when multiple rings exist independently) is preferably 5 to 15, and particularly preferably 7 to 10.

[0068] Specifically, examples of alicyclic monomers include cyclohexyl methacrylate, dicyclopentyl methacrylate, adamantane methacrylate, isobornyl methacrylate, dicyclopentenyl methacrylate, and dicyclopentenyloxyethyl methacrylate. Among these, from the perspective of easily satisfying the aforementioned physical properties while exhibiting good adhesion, dicyclopentyl methacrylate (10 carbon atoms in the alicyclic structure), adamantane methacrylate (10 carbon atoms in the alicyclic structure), or isobornyl methacrylate (7 carbon atoms in the alicyclic structure) are preferred, with isobornyl methacrylate being particularly preferred, and isobornyl methacrylate being even more preferred. These alicyclic monomers can be used alone or in combination of two or more.

[0069] When the (meth)acrylate polymer (A) contains an alicyclic monomer as a monomer unit constituting the polymer, from the perspective of easily satisfying the aforementioned physical properties and easily achieving good adhesion, it is preferable to contain 1 to 40% by mass, more preferably 4 to 32% by mass, particularly preferably 8 to 24% by mass, and even more preferably 12 to 16% by mass of the alicyclic monomer.

[0070] The (meth)acrylate polymer (A) preferably contains a nitrogen-containing monomer as a monomeric unit constituting the polymer. By having a nitrogen-containing monomer as a structural unit in the polymer, the adhesive can be endowed with a specified polarity, making it an adhesive with excellent affinity even for adhesives with a certain degree of polarity, such as glass. From the perspective of giving the (meth)acrylate polymer (A) suitable rigidity, a monomer having a nitrogen-containing heterocycle is preferred as the nitrogen-containing monomer. Furthermore, from the perspective of increasing the degree of freedom of the portion from the aforementioned nitrogen-containing monomer in the high-dimensional structure of the constructed adhesive, it is preferable that the nitrogen-containing monomer does not contain reactive unsaturated double bond groups other than one polymerizable group used in the polymerization of the (meth)acrylate polymer (A).

[0071] Examples of monomers having nitrogen-containing heterocycles include N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-(meth)acryloylaziridine, aziridineylethyl(meth)acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazolium, N-vinylcarbazole, and N-vinylphthalimide. Among these, N-(meth)acryloylmorpholine, which exhibits superior adhesive properties, is preferred, and N-acryloylmorpholine is particularly preferred. These monomers having nitrogen-containing heterocycles can be used alone or in combination of two or more.

[0072] When the (meth)acrylate polymer (A) contains a nitrogen-containing monomer as a monomer unit constituting the polymer, it is preferable to contain 1 to 30% by mass, more preferably 2 to 20% by mass, particularly preferably 3 to 12% by mass, and even more preferably 4 to 8% by mass of the nitrogen-containing monomer. Thus, the resulting adhesive can fully exert excellent adhesion to the adherend while easily satisfying the aforementioned physical properties.

[0073] The (meth)acrylate polymer (A) may also contain other monomers as constituent units, depending on the desired purpose. To avoid hindering the aforementioned effects of monomers containing reactive functional groups, monomers without reactive functional groups are preferred as other monomers. Examples of such monomers include methoxyethyl methacrylate, ethoxyethyl methacrylate, alkoxyalkyl methacrylates, vinyl acetate, and styrene. These other monomers may be used alone or in combination of two or more.

[0074] The (meth)acrylate polymer (A) is preferably a linear polymer. Because it is a linear polymer, it is easier for the molecular chains to become entangled, which can be expected to increase cohesive strength.

[0075] (Meth)acrylate polymer (A) can be obtained by solution polymerization, solvent-free polymerization, or emulsion polymerization. Among these methods, solution polymers obtained by solution polymerization are preferred from the perspective of easily obtaining high molecular weight polymers and adhesives with excellent durability.

[0076] The polymerization of (meth)acrylate polymer (A) can be either random copolymer or block copolymer.

[0077] The weight-average molecular weight of the (meth)acrylate polymer (A) is preferably 100,000 to 2,000,000, more preferably 200,000 to 1,600,000, particularly preferably 300,000 to 1,200,000, further preferably 400,000 to 900,000, and most preferably 450,000 to 700,000. This readily satisfies the aforementioned creep strain while also readily achieving the desired adhesive properties. Here, the weight-average molecular weight in this specification is a value converted from standard polystyrene determined using gel permeation chromatography (GPC).

[0078] In addition, in the adhesive composition P, the (meth)acrylate polymer (A) can be used alone or in combination of two or more.

[0079] In this embodiment, the content of (meth)acrylate polymer (A) in the adhesive composition P is preferably 60-99.9% by mass, more preferably 65-99.5% by mass, particularly preferably 70-99% by mass, and even more preferably 75-98% by mass. This results in good adhesion while easily satisfying the aforementioned physical properties.

[0080] (1-2) Crosslinking agent (B) As a crosslinking agent (B), any agent can react with the reactive groups present in the (meth)acrylate polymer (A). Examples of crosslinking agents (B) include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, amine-based crosslinking agents, melamine-based crosslinking agents, aziridine-based crosslinking agents, hydrazine-based crosslinking agents, aldehyde-based crosslinking agents, oxazoline-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, and ammonium salt-based crosslinking agents. Furthermore, crosslinking agent (B) can be used alone or in combination of two or more.

[0081] When the reactive group of the (meth)acrylate polymer (A) is hydroxyl, it is preferable to use an isocyanate-based crosslinking agent that is highly reactive with the hydroxyl group.

[0082] Isocyanate-based crosslinking agents contain at least a polyisocyanate compound. Examples of polyisocyanate compounds include: aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and diphenylmethylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; their biuret and isocyanurate forms; and adducts as reaction products with low-molecular-weight compounds containing active hydrogen, such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. From the perspective of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates are preferred, and trimethylolpropane-modified toluene diisocyanate is particularly preferred.

[0083] The content of crosslinking agent (B) in the adhesive composition P is preferably 0.01 to 2 parts by mass relative to 100 parts by mass of (meth)acrylate polymer (A), more preferably 0.04 to 1 part by mass, particularly preferably 0.07 to 0.5 parts by mass, and even more preferably 0.1 to 0.2 parts by mass. As a result, the cohesive strength and adhesive force of the obtained adhesive are easily suitable, readily satisfying the aforementioned physical properties.

[0084] (1-3) Silane coupling agent (C) The adhesive composition P preferably further contains a silane coupling agent (C). This increases the adhesion to the adhered objects, and the resulting adhesive readily achieves the desired adhesive strength.

[0085] As a silane coupling agent (C), an organosilicon compound that is well compatible with (meth)acrylate polymer (A), has light transmittance, and has at least one alkoxysilyl group in the molecule is preferred.

[0086] Examples of silane coupling agents (C) include: vinyltrimethoxysilane, vinyltriethoxysilane, methacryloyloxypropyltrimethoxysilane, and other silicon compounds containing polymerizable unsaturated groups; 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and other silicon compounds with epoxy structures; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, etc. Silicate-containing silicon compounds such as methoxymethylsilane; amino-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane; condensates of 3-chloropropyltrimethoxysilane, 3-isocyanopropyltriethoxysilane, or at least one thereof with alkyl-containing silicon compounds such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane. These silane coupling agents can be used alone or in combination of two or more.

[0087] The content of silane coupling agent (C) in the adhesive composition P is preferably 0.01 to 1 part by weight relative to 100 parts by weight of (meth)acrylate polymer (A), more preferably 0.1 to 0.7 parts by weight, and particularly preferably 0.2 to 0.5 parts by weight. This results in good adhesion to the adhered material.

[0088] (1-4) Active energy ray curing component (D) The adhesive composition P preferably further contains an active energy ray curable component (D). Thus, the resulting adhesive is active energy ray curable. The adhesive laminate 11 containing the active energy ray curable component (D) and comprising an adhesive formed by active energy ray curing exhibits lower creep strain and superior laser cutting machinability.

[0089] The active energy ray curable component (D) is not particularly limited as long as it is a component that can be cured by irradiation with active energy rays and achieve the above-mentioned effect. It can be any one of monomers, oligomers, or polymers, or a mixture thereof. Among them, multifunctional acrylate monomers with better adhesion after curing are preferred.

[0090] Examples of multifunctional acrylate monomers include: 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl adipate di(meth)acrylate, neopentyl hydroxypentyl adipate di(meth)acrylate, dicyclopentyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate phosphate, di(acryloyloxyethyl)isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, and 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, etc. Bifunctional types; trifunctional types such as trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tri(acryloyloxyethyl)isocyanurate, and ε-caprolactone-modified tri-(2-(meth)acryloyloxyethyl)isocyanurate; tetrafunctional types such as diglycerol tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate; pentafunctional types such as propionic acid-modified dipentaerythritol penta(meth)acrylate; and hexafunctional types such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate. Among the above, from the perspective of minimizing creep strain after curing with active energy rays, polyfunctional acrylate monomers containing an isocyanurate structure, such as di(acryloyloxyethyl)isocyanurate, tri(acryloyloxyethyl)isocyanurate, and ε-caprolactone-modified tri-(2-(meth)acryloyloxyethyl)isocyanurate, are preferred. Polyfunctional acrylate monomers with 3 or more functions and containing an isocyanurate structure are more preferred, and ε-caprolactone-modified tri-(2-(meth)acryloyloxyethyl)isocyanurate is particularly preferred. These polyfunctional acrylate monomers can be used alone or in combination of two or more. Furthermore, from the perspective of compatibility with other blending materials such as (meth)acrylate polymer (A), the polyfunctional acrylate monomers preferably have a molecular weight of less than 5000, more preferably less than 3000, and particularly preferably less than 1000.

[0091] From the perspective of minimizing creep strain after curing with active energy rays, the content of active energy ray curable component (D) in adhesive composition P is preferably 1 to 20 parts by mass relative to 100 parts by mass of (meth)acrylate polymer (A), particularly preferably 3 to 12 parts by mass, and even more preferably 4 to 8 parts by mass.

[0092] (1-5) Photopolymerization initiator (E) When the adhesive composition P contains an active energy ray curable component (D) and uses ultraviolet light as the active energy ray, it preferably contains a photopolymerization initiator (E). This allows for effective curing of the active energy ray curable component (D) and results in less creep strain after active energy ray curing. Furthermore, it reduces polymerization curing time and the amount of ultraviolet light irradiation required.

[0093] Examples of photopolymerization initiators (E) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propane-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, and p-phenyldiphenyl Methyl ketone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligomer [2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, etc. These photopolymerization initiators can be used alone or in combination of two or more.

[0094] The content of photopolymerization initiator (E) in the adhesive composition P is preferably 2 to 20 parts by mass relative to 100 parts by mass of the active energy ray curable component (D), particularly preferably 4 to 18 parts by mass, and even more preferably 6 to 15 parts by mass. This results in lower creep strain after active energy ray curing.

[0095] (1-6) Various additives Various additives commonly used in acrylic adhesives, such as fillers, colorants, ultraviolet absorbers, infrared absorbers, refractive index modifiers, antistatic agents, tackifiers, rust inhibitors, antioxidants, light stabilizers, and oxygen absorbers, can be added to the adhesive composition P as needed. Furthermore, the polymerization solvents or diluting solvents described later are not included in the additives constituting the adhesive composition P.

[0096] (1-6-1) Packing If the adhesive composition P contains light-diffusing microparticles as fillers, it is easier to suppress uneven brightness or to adjust the emission color of the light source to the desired color. Examples of light-diffusing microparticles include: inorganic light-diffusing microparticles such as silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and titanium dioxide; organic light-diffusing microparticles such as acrylic resins, polystyrene resins, polyethylene resins, epoxy resins, copolymers or mixtures of these light-diffusing microparticles; light-diffusing microparticles composed of silicone resins (e.g., the Tospearl series manufactured by Momentive Performance Materials Japan), which are silicon-containing compounds with an intermediate structure between inorganic and organic components; and light-diffusing microparticles composed of mixtures of organic resins and silicone resins. Among these, light-diffusing microparticles composed of silicone resins (silicon-containing compounds with an intermediate structure between inorganic and organic components) are preferred. This makes it easier to obtain the aforementioned effects. The above-mentioned light-diffusing microparticles can be used alone or in combination of two or more.

[0097] As for the shape of the light-diffusing particles, spherical light-diffusing particles with uniform light diffusion are preferred, and perfectly spherical light-diffusing particles are particularly preferred, but are not limited thereto.

[0098] The average particle size of the light-diffusing particles (based on the average particle size of the centrifugal sedimentation light transmission method) is preferably 0.5~20μm, more preferably 1~15μm, particularly preferably 2~11μm, further preferably 3~8μm, and preferably 4~6μm.

[0099] In addition, the average particle size based on the centrifugal sedimentation light transmission method is the value obtained by using a centrifugal automatic particle size distribution measuring device (manufactured by HORIBA, Ltd., product name "CAPA-700") as the sample to be measured by thoroughly stirring 1.2g of light-diffusing microparticles and 98.8g of isopropanol.

[0100] The refractive index of the light-diffusing particles is preferably 1.30 to 2.00, more preferably 1.35 to 1.85, particularly preferably 1.40 to 1.65, and even more preferably 1.42 to 1.55. Furthermore, the refractive index of the light-diffusing particles can be determined using Method B of JIS K7142:2008.

[0101] When the adhesive composition P contains light-diffusing microparticles, the content is preferably 1 to 40 parts by weight, more preferably 3 to 32 parts by weight, particularly preferably 5 to 24 parts by weight, and even more preferably 7 to 18 parts by weight, relative to 100 parts by weight of the (meth)acrylate polymer (A).

[0102] (1-6-2) Coloring agent If the adhesive composition P contains a colorant, it can impart the desired hue to the first adhesive layer 12 or the second adhesive layer 13. Thus, the desired appearance and light transmittance can be obtained.

[0103] Coloring agents can be pigments or dyes. Pigments can be inorganic or organic. Dyes can be natural or synthetic. The color of the coloring agent can be selected appropriately according to the purpose.

[0104] Inorganic pigments include, for example, carbon black pigments, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, ITO (indium tin oxide) pigments, and ATO (antimony tin oxide) pigments.

[0105] As organic pigments and dyes, examples include amine pigments, anthocyanin pigments, quinoline pigments, croconium pigments, squarylium pigments, azulenium pigments, polymethystyl pigments, naphthoquinone pigments, pyran pigments, phthalocyanine pigments, naphthocyanin pigments, naphtholactam pigments, azo pigments, condensed azo pigments, and indigo pigments. Pigments, including perinone pigments, perylene pigments, dioxazine pigments, quinacridone pigments, isoindolineone pigments, quinolineone pigments, pyrrole pigments, indigo pigments, metal complex pigments (metal complex salt dyes), dithiol metal complex pigments, indophenol pigments, triarylmethane pigments, anthraquinone pigments, dioxazine pigments, naphthol pigments, azomethyl alkaloid pigments, benzimidazole pigments, pinantrone pigments, and threne pigments, etc.

[0106] Examples of black pigments include carbon black, copper oxide, iron oxide, manganese dioxide, aniline black, and activated carbon. Additionally, examples of black dyes include high-concentration plant dyes and azo dyes.

[0107] In addition, the above pigments or dyes may be used in appropriate mixtures depending on the purpose.

[0108] From an optical properties perspective, the colorant preferably satisfies the characteristics shown below. By using an appropriate amount of a colorant that satisfies the characteristics shown below, it is easy to obtain an adhesive sheet that exhibits the desired optical properties.

[0109] For the colorant, the average haze value of the liquid obtained by diluting the colorant by ethyl acetate by 10,000 times at a wavelength of 780 nm and at a wavelength of 380 nm, i.e., the average haze value, is preferably 1 to 60%, more preferably 2 to 40%, particularly preferably 3 to 30%, further preferably 3.5 to 20%, and preferably 4 to 10%.

[0110] For the colorant, the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm obtained by diluting the colorant by ethyl acetate 10,000 times is preferably 0 to 30 percentage points, more preferably 1 to 20 percentage points, particularly preferably 2 to 10 percentage points, and even more preferably 3 to 8 percentage points.

[0111] For the colorant, the haze value of the liquid obtained by diluting the colorant 10,000 times with ethyl acetate at a wavelength of 780 nm is preferably 0.1-50%, more preferably 0.5-30%, particularly preferably 1-20%, and even more preferably 2-10%. Furthermore, the haze value of the liquid obtained by diluting the colorant 10,000 times with ethyl acetate at a wavelength of 380 nm is preferably 1-60%, more preferably 3-40%, particularly preferably 6-30%, and even more preferably 10-20%.

[0112] For the colorant, the standard deviation of the haze value of the liquid obtained by diluting the colorant 10,000 times with ethyl acetate at each wavelength (i.e., 380nm, 385nm, 390nm...775nm, 780nm) at every 5nm interval in the wavelength region of 380nm to 780nm is preferably 0.1 to 10, more preferably 0.4 to 7, particularly preferably 0.8 to 4, and even more preferably 1 to 2.

[0113] When the adhesive composition P contains a colorant (especially a pigment), the content of the colorant (especially a pigment) is preferably 0.01 to 10 parts by weight relative to 100 parts by weight of the (meth)acrylate polymer (A), more preferably 0.05 to 5 parts by weight, particularly preferably 0.1 to 2 parts by weight, further preferably 0.15 to 1.5 parts by weight, and preferably 0.2 to 1 part by weight.

[0114] (2) Preparation of adhesive composition P The adhesive composition P can be prepared by preparing a (meth)acrylate polymer (A), mixing the obtained (meth)acrylate polymer (A) with a crosslinking agent (B), and adding, as needed, a silane coupling agent (C), an active energy radiation curable component (D), a photopolymerization initiator (E), additives, etc.

[0115] (Meth)acrylate polymer (A) can be prepared by polymerizing a mixture of monomers constituting the polymer using conventional free radical polymerization. The polymerization of (meth)acrylate polymer (A) is preferably carried out using a polymerization initiator and solution polymerization, depending on the desired method. However, the invention is not limited thereto, and polymerization can also be carried out in a solvent-free environment. Examples of polymerization solvents include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc., and two or more may be used simultaneously.

[0116] Examples of polymerization initiators include azo compounds and organic peroxides, and two or more can be used simultaneously. Furthermore, in the above polymerization process, the weight-average molecular weight of the resulting polymer can be adjusted by incorporating chain transfer agents such as 2-mercaptoethanol.

[0117] After obtaining (meth)acrylate polymer (A), a crosslinking agent (B) is added to a solution of (meth)acrylate polymer (A), and silane coupling agent (C), active energy radiation curable component (D), photopolymerization initiator (E), additives, diluent, etc., are added as needed, and the mixture is thoroughly mixed to obtain a solvent-diluted adhesive composition P (coating solution). Furthermore, if any of the above components are used as solid substances, or if precipitation occurs when mixed with other components in an undiluted state, the component can be dissolved or diluted separately in a diluent before mixing with other components.

[0118] As diluents for the above, the following can be used: aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and vinyl chloride; alcohols such as methanol, ethanol, propanol, butanol, and 1-methoxy-2-propanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; and solvents such as ethyl cellosolve.

[0119] The concentration and viscosity of the coating solution prepared in the above manner are not particularly limited as long as they are within a coatable range and can be appropriately selected according to the situation. For example, the concentration of the adhesive composition P can be diluted to 10-60% by mass. Furthermore, the addition of a diluent is not necessary when obtaining the coating solution; as long as the adhesive composition P has a coatable viscosity, a diluent may not be added. In this case, the adhesive composition P is a coating solution in which the polymerization solvent of the (meth)acrylate polymer (A) is used directly as the diluent.

[0120] (3) Formation of adhesive layer In this embodiment, the first adhesive layer 12 and the second adhesive layer 13 are preferably composed of an adhesive formed by crosslinking the adhesive composition P (coating layer). The crosslinking of the adhesive composition P can usually be carried out by heat treatment. Alternatively, the drying process that causes the diluent or the like to evaporate from the coating layer of the adhesive composition P applied to the desired object can also be used as the heat treatment.

[0121] The heating temperature for the heat treatment is preferably 50~150℃, and more preferably 70~120℃. Furthermore, the heating time is preferably 10 seconds~10 minutes, and more preferably 50 seconds~2 minutes.

[0122] After heat treatment, a curing period of approximately 1-2 weeks can be set at room temperature (e.g., 23°C, 50% relative humidity) as needed. If this curing period is required, the adhesive will form after the curing period; otherwise, the adhesive will form directly after the heat treatment is completed.

[0123] Through the above heat treatment (and aging), the (meth)acrylate polymer (A) is cross-linked by the cross-linking agent (B) to obtain an adhesive.

[0124] Furthermore, when the adhesive composition P contains an active energy ray curing component (D), it is preferable to apply the adhesive layer to the substrate in the state before irradiation with the active energy ray, and then irradiate it with the active energy ray. This results in superior adhesion to the substrate and facilitates the achievement of the desired tightness.

[0125] (4) Thickness of adhesive layer The thicknesses of the first and second adhesive layers (measured according to JIS K7130) are preferably 1 to 100 μm, more preferably 10 to 96 μm, particularly preferably 20 to 92 μm, and even more preferably 30 to 90 μm, wherein 40 to 88 μm is preferred. Thus, while maintaining the required adhesion, the aforementioned creep strain is easily satisfied.

[0126] 1-1-2. Core material For the core material 14, it is sufficient as long as the adhesive laminate 11, which includes the first adhesive layer 12 and the second adhesive layer 13, satisfies the aforementioned creep strain, preferably it is made of a plastic film.

[0127] Examples of plastic films include polyester films made from polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyurethane films; polyethylene films; polypropylene films; cellulose films such as cellulose triacetate; polyvinyl chloride films; polyvinylidene chloride films; polyvinyl alcohol films; ethylene-vinyl acetate copolymer films; polystyrene films; polycarbonate films; acrylic resin films; norbornene resin films; cyclic olefin resin films; and laminates of two or more of the above films. The plastic film can be formed by uniaxial stretching or biaxial stretching. Polyester films are preferred, and polyethylene terephthalate films are particularly preferred. This type of plastic film more readily satisfies the aforementioned creep strain.

[0128] In addition, from the perspective of SDGs, materials that constitute the core material can be materials with high biomass content, materials that are recyclable or reusable, or materials that have been recycled or reused.

[0129] For the core material 14 made of plastic film described above, in order to improve the adhesion with the adjacent first adhesive layer 12 and / or second adhesive layer 13, surface treatment or primer treatment by oxidation or the like can be applied to one or both sides as needed. Examples of such oxidation methods include corona discharge treatment, plasma discharge treatment, wet chromium oxidation treatment, flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment. These surface treatment methods can be appropriately selected according to the type of plastic film, but from the perspective of effectiveness and operability, corona discharge treatment is generally preferred.

[0130] The thickness of the core material 14 is preferably 1~300μm, more preferably 10~250μm, particularly preferably 15~200μm, and even more preferably 20~150μm, wherein 25~120μm is preferred. This readily satisfies the aforementioned creep strain.

[0131] For the tensile strength (fracture stress) of the core material 14, MD (the direction along the production line during manufacturing) is preferably 10 to 10,000 MPa, more preferably 50 to 5,000 MPa, particularly preferably 100 to 1,000 MPa, and even more preferably 200 to 500 MPa. Furthermore, TD (the direction orthogonal to MD) is preferably 10 to 10,000 MPa, more preferably 50 to 5,000 MPa, particularly preferably 100 to 1,000 MPa, and even more preferably 200 to 500 MPa. The tensile strength (fracture stress) of the core material is measured using the same method as the tensile test described later in the experimental examples.

[0132] For the elongation of the core material 14, MD is preferably 10-1000%, more preferably 50-600%, particularly preferably 80-400%, and even more preferably 100-200%. Furthermore, TD is preferably 10-1000%, more preferably 40-600%, particularly preferably 70-400%, and even more preferably 90-200%. The method for determining the elongation of the core material is based on JIS C2318.

[0133] For the dimensional change rate of the core material 14 due to heating (with shrinkage set as negative and elongation set as positive), MD is preferably 0.1-5%, more preferably 0.15-3%, particularly preferably 0.2-2%, and even more preferably 0.25-1%. Furthermore, TD is preferably 0.1-5%, more preferably 0.15-3%, particularly preferably 0.2-2%, and even more preferably 0.25-1%. The dimensional change rate of the core material is measured using the same method as the method used to measure the dimensional change rate in the experimental examples described later.

[0134] As the core material 14, commercially available products can be used, such as "CosmoShine (registered trademark) A4360 100μm" manufactured by TOYOBO CO., LTD., which is preferred.

[0135] 1-1-3. Peeling sheet As release sheets 16a and 16b, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene-(meth)acrylate copolymer film, ethylene-(meth)acrylate polymer film, polystyrene film, polycarbonate film, polyimide film, fluoropolymer film, etc. Furthermore, cross-linked films of these films can also be used. These films can also be further laminated. Additionally, from the perspective of SDGs, materials with high biomass content, recyclable or reusable materials, or materials that have been recycled or reused can be used as the materials constituting the release sheets.

[0136] It is preferable to perform the peeling treatment on the peeling surfaces of the release sheets 16a and 16b (especially the surfaces that contact the adhesive layers 12 and 13). Examples of release agents used for the peeling treatment include alkyd, silicone, fluorinated, unsaturated polyester, polyolefin, and wax-based release agents.

[0137] The thickness of the release strips 16a and 16b is not particularly limited, but is generally preferred to be 10 to 250 μm, and particularly preferred to be 20 to 150 μm.

[0138] Preferably, one of the two peeling sheets 16a and 16b is a heavy-peeling peeling sheet with high peeling force, and the other peeling sheet is a light-peeling peeling sheet with low peeling force.

[0139] 1-2. Manufacturing Method As a manufacturing example of adhesive sheet 1A, the use of the above-described adhesive composition P will be described. In a preferred manufacturing example, a coating solution of the adhesive composition P for forming the first adhesive layer 12 is applied to the release surface of a release sheet 16a, and then heat-treated to thermally crosslink the adhesive composition P, forming a first coating layer. Next, a core material 14 is laminated onto this coating layer. Furthermore, a coating solution of the adhesive composition P for forming the second adhesive layer 13 is applied to the release surface of another release sheet 16b, and then heat-treated to thermally crosslink the adhesive composition P, forming a second coating layer. This second coating layer is then bonded to the core material 14 that has been laminated onto the first coating layer. When a curing period is required, by setting a curing period, the first coating layer becomes the first adhesive layer 12 and the second coating layer becomes the second adhesive layer 13. When a curing period is not required, the first coating layer directly becomes the first adhesive layer 12 and the second coating layer directly becomes the second adhesive layer 13. Thus, the adhesive sheet 1A is obtained. The heat treatment and curing conditions are as described above.

[0140] As another manufacturing example of the adhesive sheet 1A, a coating solution of the adhesive composition P for forming the first adhesive layer 12 is applied to one side of the core material 14, and heat treatment is performed to thermally crosslink the adhesive composition P to form a first coating layer. Then, a release sheet 16a is laminated on the first coating layer with its release surface in contact with the first coating layer, forming a first laminate. On the other hand, a coating solution of the adhesive composition P for forming the second adhesive layer 13 is applied to the release surface of the release sheet 16b, and heat treatment is performed to thermally crosslink the adhesive composition P to form a second coating layer, forming a second laminate. Next, the first laminate and the second laminate are bonded together such that the core material 14 of the first laminate is laminated with the second coating layer of the second laminate. When a curing period is required, by setting a curing period, the first coating layer becomes the first adhesive layer 12 and the second coating layer becomes the second adhesive layer 13. When a curing period is not required, the first coating layer directly becomes the first adhesive layer 12 and the second coating layer directly becomes the second adhesive layer 13. Thus, the adhesive sheet 1A is obtained.

[0141] Methods for applying the coating solution of the adhesive composition P can include, for example, rod coating, blade coating, roller coating, comma coating, scraper coating, mold coating, gravure coating, screen coating, etc.

[0142] 1-3. Physical properties (thickness of the adhesive laminate) The thickness of the adhesive laminate 11 (measured according to JIS K7130) is preferably 1 to 500 μm, more preferably 25 to 420 μm, particularly preferably 50 to 360 μm, and even more preferably 75 to 300 μm, wherein 100 to 250 μm is preferred. This readily satisfies the aforementioned creep strain.

[0143] 2. Adhesive sheet of the second implementation scheme 2-1. Constituent Elements 2-1-1. Adhesive layer The adhesive of the adhesive layer 15 constituting the adhesive sheet 1B of the second embodiment only needs to satisfy the aforementioned creep strain as the adhesive layer 15. As an adhesive that easily satisfies this creep strain, adhesives containing epoxy resin (hereinafter sometimes referred to as "epoxy resin-based adhesives") or polyester-based adhesives are preferably listed.

[0144] (1) Epoxy resin adhesive Epoxy resin-based adhesives readily meet the aforementioned creep strain requirements. Preferably, they are adhesives that are active energy radiation-curable, containing an epoxy resin (F) with a glass transition temperature (Tg) of 50°C or higher, an epoxy resin (G) providing a cured product with a Tg of 25°C or lower, and a cationic polymerization initiator (H). These adhesives are more likely to meet the aforementioned creep strain requirements. Furthermore, from the perspective of SDGs (Safety, Health, and Development Groups), materials with high biomass content, recyclable or reusable materials, or materials that have already been recycled or reused can be used as the constituent materials of the epoxy resin-based adhesive.

[0145] The epoxy resin (F) has a Tg of 50°C or higher, preferably 80°C or higher, more preferably 100°C or higher, particularly preferably 120°C or higher, and even more preferably 140°C or higher. There is no particular upper limit to this Tg value, but from the perspective of coatability, it is preferably below 200°C, more preferably below 180°C, particularly preferably below 160°C, and even more preferably below 155°C. The Tg of the epoxy resin (F) can be measured using a differential scanning calorimeter according to JIS K7121. By using this epoxy resin (F), the adhesive layer 15 has a certain degree of hardness, and even if the adhesive layer 15 is a single layer, it easily meets the aforementioned creep strain requirements.

[0146] The weight-average molecular weight (Mw) of the epoxy resin (F) is preferably 10,000 to 300,000, particularly preferably 18,000 to 200,000, and even more preferably 26,000 to 100,000.

[0147] Phenoxy resins are preferably examples of epoxy resins (F). Phenoxy resins can be obtained by reacting a difunctional phenol with an epihaloalcohol to a high molecular weight, or by performing an addition polymerization reaction between a difunctional epoxy resin and a difunctional phenol. Furthermore, commercially available products can also be used as phenoxy resins. Examples include YX7200 (Tg: 150°C) and YX6954 (a phenoxy resin containing a bisphenol acetophenone backbone, Tg: 130°C) manufactured by Mitsubishi Chemical Corporation, and YP70 (Tg: 70°C) manufactured by NIPPON STEEL Chemical & Material Co., Ltd.

[0148] The epoxy resin (F) content in the total epoxy resin adhesive is preferably 20-90% by mass, more preferably 30-80% by mass, particularly preferably 40-70% by mass, and even more preferably 45-60% by mass. Therefore, the resulting adhesive layer 15 has a certain degree of hardness, and even if the adhesive layer 15 is a single layer, it easily meets the aforementioned creep strain requirements.

[0149] Epoxy resin (G) providing a cured product with a Tg of 25°C or lower refers to an epoxy resin that provides a cured product with a Tg of 25°C or lower when cured alone or in the presence of a polymerization initiator or the like. By using epoxy resin (G), an adhesive with active energy ray curing properties can be obtained, which can be fully cured by irradiation with active energy rays even without heat treatment. From this perspective, epoxy resin (G) preferably provides a cured product with a Tg of -5°C or lower, more preferably a cured product with a Tg of -20°C or lower, particularly preferably a cured product with a Tg of -40°C or lower, and even more preferably a cured product with a Tg of -60°C or lower. The lower limit of the above Tg is not particularly limited, and is generally -100°C or higher. From the perspective of easily achieving the desired creep strain or tack, -90°C or higher is preferred, and -80°C or higher is more preferred. Furthermore, the Tg of the cured epoxy resin (G) can be measured using a differential scanning calorimeter according to JIS K 7121.

[0150] The epoxy resin (G) is preferably liquid at 23°C. "Liquid at 23°C" means that it has fluidity at 23°C. By using an epoxy resin that is liquid at 23°C, and exhibiting tackiness at room temperature or mildly high temperatures, an adhesive with excellent adhesion can be obtained.

[0151] The epoxy equivalent of the epoxy resin (G) is preferably 100-500 g / eq, and particularly preferably 115-450 g / eq. This allows for the preparation of an adhesive layer with excellent bonding strength. Furthermore, the epoxy equivalent value can be determined according to JIS K7236.

[0152] From the perspective of providing cured products with relatively low Tg, epoxy resins having oxyalkylene structures are preferred as epoxy resins (G).

[0153] Examples of oxoalkylene structures include oxomethylene, oxoethylene, oxopropylene, oxomethylenetrimethylene, oxobutylene, oxopentylene, oxohexylene, oxohepylene, oxoctylene, oxonylene, oxdecylene, oxundecylene, oxododecylene, oxotridecylene, oxotetradecylene, oxoctadecanylene, oxocyclopropylene, oxocyclobutylene, oxocyclopentylene, oxocyclohexylene, oxodecahydronaphthylene, oxonorbornylene, and oxadamantylene.

[0154] As an epoxy resin with an oxyalkylene structure and liquid at 23°C, commercially available products can be used. For example, the product manufactured by Mitsubishi Chemical Corporation, under the brand name YX7400 (cured product Tg: -69°C, epoxy equivalent: 440 g / eq), can be used.

[0155] The epoxy resin (G) content in the total epoxy resin adhesive is preferably 20-90% by mass, more preferably 30-80% by mass, particularly preferably 40-70% by mass, and even more preferably 45-60% by mass. Therefore, the resulting adhesive layer 15 exhibits good adhesion, and the adhesive layer 15 cured by active energy rays also possesses good hardness. Even if the adhesive layer 15 is a single layer, it easily meets the aforementioned creep strain requirements.

[0156] The cationic polymerization initiator (H) can be any polymerization initiator that generates cationic species through at least one of irradiation by active energy rays and heating, and carries out the polymerization reaction of the epoxy resin (G) described above. Preferably, it is a polymerization initiator that generates cationic species through irradiation by active energy rays, and particularly preferably it is a polymerization initiator that generates cationic species through irradiation by ultraviolet light (cationic photopolymerization initiator).

[0157] Cationic photopolymerization initiators facilitate the polymerization reaction of epoxy resin (G) and, compared to other curing agents, improve the storage stability of the resulting adhesive layer 15, are therefore preferred. The cationic photopolymerization initiator consists of a cationic portion that absorbs ultraviolet light and an anionic portion that serves as an acid generation source.

[0158] Examples of cationic photopolymerization initiators include sulfonium salt compounds, iodonium salt compounds, phosphonium salt compounds, ammonium salt compounds, diazonium salt compounds, selenium salt compounds, oxonium salt compounds, and bromide salt compounds. Among these, sulfonium salt compounds are preferred for their excellent compatibility with other components, and aromatic sulfonium salt compounds having aromatic groups are more preferred.

[0159] Examples of sulfonium salt compounds include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetra(pentafluorophenyl)borate, 4,4'-bis[diphenylsulfonium]diphenyl sulfide-bis(hexafluorophosphate), 4,4'-bis[bis(β-hydroxyethoxy)phenylsulfonium]diphenyl sulfide-bis(hexafluoroantimonate), 7-[bis(p-tolyl)sulfonium]-2-isopropylthioxanthone hexafluorophosphate, and 7-[bis(p-tolyl)sulfonium]... ]-2-Isopropylthioxanthone hexafluoroantimonate, 7-[bis(p-tolyl)sulfonium]-2-isopropyltetra(pentafluorophenyl)borate, benzoyl-4'-diphenylsulfonium-diphenyl sulfide-hexafluorophosphate, benzoyl-4'-diphenylsulfonium-diphenyl sulfide-hexafluoroantimonate, 4-tert-butylbenzoyl-4'-diphenylsulfonium-diphenyl sulfide-hexafluorophosphate, 4-tert-butylbenzoyl-4'-diphenylsulfonium-diphenyl sulfide- Hexafluoroantimonate, 4-tert-butylbenzoyl-4'-diphenylsulfonyl-diphenylsulfide-tetra(pentafluorophenyl)borate, 4-(phenylthio)phenyldiphenylsulfonylhexafluoroantimonate, 4-(phenylthio)phenyldiphenylsulfonylhexafluorophosphate, 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonylhexafluoroantimonate, halides of phenylthiodiphenylsulfonylhexafluoroantimonate, 4,4',4''-tris(β-hydroxyethyl) Examples of cationic photopolymerization initiators include (oxyphenyl)sulfonium hexafluoroantimonate, 4,4'-bis[diphenylsulfonium]diphenyl sulfide-bishexafluoroantimonate, diphenyl[4-(phenylthio)phenyl]sulfonium trifluorotris(pentafluoroethyl)phosphate, tris[4-(4-acetylphenylthio)phenyl]sulfonium tris[(trifluoromethyl)sulfonyl]methanide, and phosphorus anions with a cationic moiety of 4-(phenylthio)phenyl diphenylsulfonium and anionic moieties containing fluorine or perfluoroalkyl groups. One type of cationic photopolymerization initiator can be used alone, or two or more can be used in combination.

[0160] The content of cationic polymerization initiator (H) in the epoxy resin adhesive is preferably 0.1 to 5% by mass, particularly preferably 0.5 to 4% by mass, and even more preferably 1 to 3% by mass. As a result, the adhesive layer 15 has a certain degree of hardness, and even if the adhesive layer 15 is a single layer, it is easy to meet the aforementioned creep strain.

[0161] Various additives can be added to epoxy resin adhesives, such as silane coupling agents, fillers, colorants, ultraviolet absorbers, infrared absorbers, refractive index modifiers, antistatic agents, tackifiers, rust inhibitors, antioxidants, light stabilizers, softeners, oxygen absorbers, etc.

[0162] Epoxy resin adhesives can be manufactured using conventional methods. When applying epoxy resin adhesives, a diluent can be added as needed to obtain a solvent-diluted coating solution. The same diluents described above can be used as diluents.

[0163] (2) Polyester adhesives Polyester-based adhesives readily meet the aforementioned creep strain requirements. Preferably, they are formed by crosslinking an adhesive composition containing a polyester polymer (I) with reactive functional groups and a crosslinking agent (B). Particularly preferred are adhesive compositions containing a polyester polymer (I) with reactive functional groups, a crosslinking agent (B), and an active energy radiation curable component (D), which are then crosslinked and cured with active energy radiation. This type of adhesive more readily meets the aforementioned creep strain requirements. Furthermore, from the perspective of SDGs (Supplemental Development Groups), materials with high biomass content, recyclable or reusable materials, or materials that have already been recycled or reused can be used as the materials constituting the polyester-based adhesive.

[0164] The polyester polymer (I) having reactive functional groups can be composed of either a saturated polyester resin or an unsaturated polyester resin. In this embodiment, the polyester polymer (I) is preferably a saturated polyester resin. A saturated polyester resin can be obtained, for example, by polycondensation of a polycarboxylic acid with a polyol.

[0165] The reactive functional groups of the polyester polymer (I) react with the crosslinking agent (B), thereby forming a crosslinked structure as a three-dimensional network in the adhesive. As a result, the aforementioned creep strain is easily satisfied.

[0166] Examples of reactive functional groups in the polyester polymer (I) include hydroxyl, carboxyl, and amino groups, among which hydroxyl groups are preferred as they have less adverse effects on the adherend. The polyester polymer (I) may have one or more of the above-mentioned reactive functional groups.

[0167] The Tg of the polyester polymer (I) is preferably -100℃ to 20℃, more preferably -60℃ to 15℃, particularly preferably -20℃ to 10℃, and even more preferably -5℃ to 5℃. This makes it easier to meet the aforementioned creep strain.

[0168] The weight-average molecular weight of the polyester polymer (I) is preferably 20,000 to 2,000,000, more preferably 50,000 to 1,400,000, particularly preferably 80,000 to 800,000, and even more preferably 100,000 to 400,000, with a preferred value of 120,000 to 200,000. This makes it easier to meet the aforementioned creep strain requirements.

[0169] In polyester adhesives, polyester polymer (I) can be used alone or in combination with two or more types.

[0170] Commercially available products can also be used as the polyester polymer (I). Examples of commercially available products include Nichigo-POLYESTER (registered trademark) NP-110S50EO, Nichigo-POLYESTER (registered trademark) S-0091S55EO, and Nichigo-POLYESTER (registered trademark) S-0097S55EO manufactured by Mitsubishi Chemical Corporation. Among these, Nichigo-POLYESTER (registered trademark) S-0097S55EO is preferred.

[0171] The content of polyester polymer (I) in the total polyester adhesive is preferably 50 to 99.9% by mass, more preferably 60 to 99% by mass, particularly preferably 65 to 95% by mass, and even more preferably 70 to 90% by mass. This makes it easier to meet the aforementioned creep strain.

[0172] As the crosslinking agent (B), any agent that can react with the reactive functional groups of the polyester polymer (I) to form a crosslinked structure is acceptable. The same crosslinking agent as used in the aforementioned embodiments can be used as the crosslinking agent (B). From the perspective of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates are preferred, and trimethylolpropane-modified toluene diisocyanate is particularly preferred.

[0173] The content of crosslinking agent (B) in the polyester adhesive is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of polyester polymer (I), more preferably 0.1 to 8 parts by mass, particularly preferably 0.4 to 6 parts by mass, further preferably 0.8 to 4 parts by mass, and most preferably 1.2 to 3 parts by mass. This makes it easier to meet the aforementioned creep strain.

[0174] When the polyester adhesive of this embodiment contains an active energy radiation-curable component (D), it is presumed that in the adhesive obtained by thermal crosslinking and active energy radiation curing of the polyester adhesive, the active energy radiation-curable component (D) polymerizes with each other, and the polymerized active energy radiation-curable component (D) is entangled in the crosslinked structure (three-dimensional network structure) of the polyester polymer (I). The adhesive with this high-dimensional structure is more likely to meet the aforementioned creep strain.

[0175] The active energy ray curable component (D) is not particularly limited as long as it is a component that is cured by irradiation with active energy rays and achieves the above-mentioned effect. The same component as the active energy ray curable component (D) in the aforementioned embodiments can be used. Among them, ethylene oxide modified di(meth)acrylate isocyanurate, ethylene oxide modified tri(meth)acrylate isocyanurate, or mixtures thereof are preferred.

[0176] When the polyester adhesive contains an active energy radiation curable component (D), this content is preferably 1 to 50 parts by mass relative to 100 parts by mass of the polyester polymer (I), more preferably 4 to 45 parts by mass, particularly preferably 8 to 40 parts by mass, further preferably 12 to 36 parts by mass, and most preferably 16 to 32 parts by mass. This makes it easier to meet the aforementioned creep strain.

[0177] When the polyester adhesive in this embodiment contains an active energy-curing component (D) and uses ultraviolet light as the active energy ray, it preferably contains a photopolymerization initiator (E). This allows for effective curing of the active energy-curing component (D) and results in less creep strain after active energy-curing. Furthermore, it reduces polymerization curing time and the amount of ultraviolet light irradiation required.

[0178] As the photopolymerization initiator (E), the same photopolymerization initiator (E) as in the aforementioned embodiments can be used.

[0179] When the polyester adhesive contains a photopolymerization initiator (E), its content relative to 100 parts by mass of the active energy ray curable component (D) is preferably 0.01 to 10 parts by mass, more preferably 0.04 to 5 parts by mass, particularly preferably 0.08 to 2 parts by mass, and even more preferably 0.1 to 1 part by mass. This results in smaller creep strain after active energy ray curing.

[0180] The polyester adhesive in this embodiment preferably further contains a catalyst (J). Therefore, in addition to promoting crosslinking and shortening the curing time of the adhesive by facilitating the formation of the crosslinked structure of the polyester adhesive, it is also easy to obtain a suitable crosslinked structure that allows the polyester adhesive to exhibit the desired properties by using an appropriate crosslinking formation rate.

[0181] Examples of metal chelate compounds whose metal atoms are aluminum, zirconium, titanium, zinc, iron, tin, etc., can be cited as catalysts (J). From a performance perspective, aluminum chelate compounds or zirconium chelate compounds are preferred, and zirconium chelate compounds are particularly preferred. Furthermore, these metal chelate compounds are preferably acetylacetone complexes.

[0182] Examples of zirconium chelating compounds include zirconium tetraacetylacetonate, zirconium tributoxyacetylacetonate, zirconium monobutoxyacetylacetonate bis(ethyl acetoacetate), and zirconium dibutoxyacetylacetonate, among which zirconium tetraacetylacetonate is preferred. These zirconium chelating compounds can be used alone or in combination of two or more.

[0183] When the polyester adhesive contains a catalyst (J), its content relative to 100 parts by weight of polyester polymer (I) is preferably 0.001 to 0.1 parts by weight, more preferably 0.005 to 0.08 parts by weight, particularly preferably 0.01 to 0.06 parts by weight, and even more preferably 0.02 to 0.04 parts by weight. This results in smaller creep strain.

[0184] Various additives can be added to polyester adhesives, such as silane coupling agents, fillers, colorants, ultraviolet absorbers, infrared absorbers, refractive index modifiers, antistatic agents, tackifiers, rust inhibitors, antioxidants, light stabilizers, softeners, oxygen absorbers, etc.

[0185] Polyester-based adhesives can be manufactured using conventional methods. When coating polyester-based adhesives, a diluent can be added as needed to obtain a solvent-diluted coating solution. The same diluents described above can be used as diluents.

[0186] (3) Thickness of adhesive layer The thickness of the adhesive layer 15 (measured according to JIS K7130) is preferably 1~100 μm, more preferably 5~90 ​​μm, more preferably 10~80 μm, particularly preferably 20~70 μm, even more preferably 30~60 μm, and most preferably 40~55 μm. Thus, while maintaining the required adhesion, it is easy to satisfy the aforementioned creep strain.

[0187] 2-1-2. Peeling sheet As release sheets 16a and 16b, the same release sheets as those of the adhesive sheet 1A in the first embodiment can be used.

[0188] 2-2. Manufacturing Method As one manufacturing example of adhesive sheet 1B, a coating solution of the adhesive constituting adhesive layer 15 is applied to the release surface of a release sheet 16a (or 16b), and heat-treated as needed to form adhesive layer 15. The release surface of another release sheet 16b (or 16a) is then laminated onto the adhesive layer 15. For the aforementioned polyester adhesive, a crosslinking reaction can be performed through heat treatment. Alternatively, the drying process, which causes the diluent or similar solvent to evaporate from the adhesive coating layer applied to the desired object, can also be used as the heat treatment.

[0189] The heating temperature for the heat treatment is preferably 50~150℃, and more preferably 70~120℃. Furthermore, the heating time is preferably 10 seconds~10 minutes, and more preferably 50 seconds~2 minutes.

[0190] In the aforementioned polyester adhesive, it is preferable to irradiate the adhesive layer with active energy rays during the stage of the adhesive sheet 1B before attaching it to the substrate, thereby curing the polyester adhesive with active energy rays. This makes it easier to meet the aforementioned creep strain.

[0191] Active energy rays refer to active energy rays containing energy quanta within electromagnetic waves or charged particle beams. Specifically, examples include ultraviolet light and electron beams. Among these, ultraviolet light, which is particularly easy to manipulate, is preferred.

[0192] Ultraviolet (UV) irradiation can be achieved using high-pressure mercury lamps, Heraeus H lamps, xenon lamps, etc., with the optimal UV irradiation intensity being 50–1000 mW / cm². 2 The preferred value is 100~600mW / cm². 2 Furthermore, the preferred light intensity is 50~10000 mJ / cm². 2 More preferably, it is 100~5000 mJ / cm 2 The preferred value is 300~2000 mJ / cm³. 2 On the other hand, electron beam irradiation can be performed using an electron beam accelerator or the like, and the preferred irradiation dose is around 10 to 1000 krad.

[0193] 2-3. Physical properties (1) Adhesion In this embodiment, the adhesion force of the adhesive sheet 1B to the soda-lime glass is preferably 0.1 N / 25 mm or more, more preferably 0.3 N / 25 mm or more, particularly preferably 0.6 N / 25 mm or more, and even more preferably 0.8 N / 25 mm or more. Therefore, during laser cutting, it is less likely for the adhesive layer 15 to lift or peel off at the interface with the adhered object (e.g., light-emitting substrate, surface substrate), resulting in excellent adhesion.

[0194] Furthermore, the upper limit of the aforementioned adhesive force is preferably 10 N / 25 mm or less, more preferably 7 N / 25 mm or less, particularly preferably 4 N / 25 mm or less, and even more preferably 2 N / 25 mm or less. This provides good reoperability, allowing the adhered material to be reused even in the event of an adhesion error.

[0195] (2) Adhesion after curing by active energy rays When the adhesive is cured by active energy radiation, the adhesion force of the adhesive sheet 1B to the soda-lime glass after the adhesive layer 15 of the adhesive sheet 1B is attached to the soda-lime glass and cured by active energy radiation (adhesion force after active energy radiation curing) is preferably 0.2 N / 25 mm or more, more preferably 1 N / 25 mm or more, particularly preferably 10 N / 25 mm or more, further preferably 25 N / 25 mm or more, and preferably 35 N / 25 mm or more, especially preferably 45 N / 25 mm or more. Therefore, during laser cutting, it is less likely for the adhesive layer 15 cured by active energy radiation to lift or peel off at the interface with the adhered object (e.g., light-emitting substrate, surface substrate), resulting in excellent adhesion.

[0196] Furthermore, the upper limit of the aforementioned adhesive force is preferably 100 N / 25 mm or less, more preferably 75 N / 25 mm or less, and particularly preferably 60 N / 25 mm or less. This provides good reoperability, allowing the adhered material to be reused even in the event of an adhesion error.

[0197] 3. Common physical properties The common physical properties of adhesive sheet 1A in the first embodiment and adhesive sheet 1B in the second embodiment are described.

[0198] (1) Elongation at break The elongation at break measured by a tensile test at a tensile speed of 200 mm / min on the adhesive laminate 11 (composed of the first adhesive layer 12, the core material 14, and the second adhesive layer 13) of adhesive sheet 1A and the adhesive layer 15 (when the adhesive layer is cured by active energy radiation, it is the adhesive laminate / adhesive layer cured by active energy radiation) of adhesive sheet 1B is preferably 1000% or less, more preferably 600% or less, particularly preferably 300% or less, further preferably 200% or less, and most preferably 150% or less. Thus, the adhesive laminate 11 and the adhesive layer 15 have a specified hardness. As a result, even when the end face of the unit panel having the adhesive laminate 11 or the adhesive layer 15 is laser-cut to form a flat surface, adhesive seepage from that end face can be suppressed. From the perspective of adhesion, the lower limit of the above-mentioned elongation at break is preferably 1% or more, more preferably 20% or more, particularly preferably 40% or more, further preferably 60% or more, and most preferably 70% or more, especially preferably 74% or more. Furthermore, in the tensile test, the measurement width is set to 10 mm and the measurement length is set to 25 mm, and the test is conducted at 23°C and 50% RH. Detailed test procedures are shown in the test examples described later.

[0199] Preferably, the above-mentioned elongation at break is satisfied in both the production line direction (MD) and the direction orthogonal to the MD (TD) during the manufacturing of the adhesive laminate 11 and the adhesive layer 15. Typically, the elongation at break of the MD tends to be greater than the elongation at break of the TD. The ratio of MD to TD (MD / TD) is preferably 0.5 to 5, more preferably 0.7 to 3, particularly preferably 0.9 to 2, and even more preferably 1 to 1.7. Therefore, when the unit panel is, for example, rectangular, adhesive seepage on each side can be suppressed during laser cutting.

[0200] (2) Fracture stress The fracture stress measured by performing a tensile test at a tensile speed of 200 mm / min on the adhesive laminate 11 (composed of the first adhesive layer 12, the core material 14, and the second adhesive layer 13) of adhesive sheet 1A and the adhesive layer 15 (when the adhesive layer is cured by active energy radiation, it is the adhesive laminate / adhesive layer cured by active energy radiation) of adhesive sheet 1B is preferably 10 MPa or more, more preferably 40 MPa or more, particularly preferably 80 MPa or more, further preferably 100 MPa or more, and most preferably 120 MPa or more. Thus, the adhesive laminate 11 and the adhesive layer 15 have a specified hardness. As a result, even when the end face of the unit panel having the adhesive laminate 11 or the adhesive layer 15 is laser-cut to form a flat surface, adhesive seepage from that end face can be suppressed. From the perspective of adhesion, the upper limit of the aforementioned fracture stress is preferably 1000 MPa or less, more preferably 750 MPa or less, particularly preferably 500 MPa or less, further preferably 300 MPa or less, and most preferably 240 MPa or less. Furthermore, in the tensile test, the measurement width is set to 10 mm and the measurement length to 25 mm, and the test is conducted at 23°C and 50% RH. Detailed test procedures are shown in the test examples described later.

[0201] Preferably, the aforementioned fracture stress is satisfied in both the production line direction (MD) and the direction orthogonal to the MD (TD) during the manufacturing of the adhesive laminate 11 and the adhesive layer 15. Typically, the fracture stress of the MD tends to be less than the fracture stress of the TD. The ratio of MD to TD (MD / TD) is preferably 0.1 to 5, more preferably 0.3 to 2, particularly preferably 0.5 to 1.5, and even more preferably 0.6 to 1. Therefore, when the unit panel is, for example, rectangular, adhesive seepage on each side can be suppressed during laser cutting.

[0202] (3) Total transmittance The lower limit of the total light transmittance of the adhesive laminate 11 composed of the first adhesive layer 12, the core material 14, and the second adhesive layer 13 in adhesive sheet 1A, and the adhesive layer 15 of adhesive sheet 1B, is preferably 10% or more, preferably 40% or more, particularly preferably 80% or more, and even more preferably 90% or more. This provides good visibility for the splicing display. On the other hand, the upper limit of the above-mentioned total light transmittance is not particularly limited and is generally 100% or less. Furthermore, when the adhesive layer is cured by active energy radiation, it is preferable that the total light transmittance is within the same range as described above both before and after active energy radiation curing. Here, the total light transmittance in this specification is a value measured according to JIS K7361-1:1997.

[0203] (4) Haze value The haze value of the adhesive laminate 11 composed of the first adhesive layer 12, the core material 14, and the second adhesive layer 13 in adhesive sheet 1A, and the adhesive layer 15 of adhesive sheet 1B, is preferably 90% or less, more preferably 60% or less, particularly preferably 30% or less, further preferably 10% or less, and most preferably 2% or less, especially preferably 1% or less. This provides good visibility for the splicing display. On the other hand, the lower limit of the above haze value is not particularly limited and is generally 0% or more. Furthermore, when the adhesive layer is cured by active energy radiation, it is preferable that the haze value is within the same range as described above both before and after active energy radiation curing. Additionally, the haze value in this specification is a value measured according to JIS K7136:2000.

[0204] (5) Dimensional change rate The dimensional change rate (with shrinkage set as negative and elongation set as positive) of the MD and TD of the adhesive laminate 11 composed of the first adhesive layer 12, core material 14 and second adhesive layer 13 in adhesive sheet 1A, and the adhesive layer 15 of adhesive sheet 1B (when the adhesive layer is cured by active energy radiation, it is the adhesive laminate / adhesive layer cured by active energy radiation) due to heating is ideally preferably 0%, practically preferably 0.01 to 10%, more preferably 0.05 to 7%, particularly preferably 0.1 to 4%, further preferably 0.2 to 2%, wherein preferably 0.25 to 1.5%, especially preferably 0.3 to 1%. Thus, the adhesive laminate 11 and adhesive layer 15 have a defined shape retention. As a result, even when the end face of the unit panel having the adhesive laminate 11 or adhesive layer 15 is laser-cut to form a flat surface, adhesive seepage from that end face can be more effectively suppressed. Furthermore, it can more effectively suppress lifting and peeling at the interface with the adhered object. Additionally, the method for measuring the dimensional change rate described above is shown in the experimental examples described later.

[0205] [Unit Panel] The unit panels of the embodiments of the present invention constitute a video wall display. An example of a unit panel of the first embodiment of the present invention is shown below. Figure 3 An example of a unit panel of the second embodiment of the present invention is shown in Figure 4 .

[0206] like Figure 3As shown, the unit panel 2A of the first embodiment of the present invention is constructed by comprising a light-emitting substrate 21, a surface substrate 22, and an adhesive laminate 11 located between the two and bonding the light-emitting substrate 21 and the surface substrate 22. The adhesive laminate 11 comprises a first adhesive layer 12, a second adhesive layer 13, and a core material 14 disposed between the first adhesive layer 12 and the second adhesive layer 13, and is obtained from the adhesive laminate 11 of the adhesive sheet 1A of the aforementioned embodiment. In this embodiment, the adhesive surface 12S of the first adhesive layer 12 is in contact with the light-emitting substrate 21, and the adhesive surface 13S of the second adhesive layer 13 is in contact with the surface substrate 22.

[0207] In addition, such as Figure 4 As shown, the unit panel 2B of the second embodiment of the present invention is constituted by having a light-emitting substrate 21, a surface substrate 22, and an adhesive layer 15 located between the two and bonding the light-emitting substrate 21 and the surface substrate 22. The adhesive layer 15 is obtained from the adhesive layer 15 of the adhesive sheet 1B of the aforementioned embodiment.

[0208] In addition, when the first adhesive layer 12 and the second adhesive layer 13 of the adhesive sheet 1A, or the adhesive layer 15 of the adhesive sheet 1B, are composed of an adhesive that can be cured by active energy rays, the first adhesive layer 12 and the second adhesive layer 13 in the aforementioned unit panel 2A, or the adhesive layer 15 in the aforementioned unit panel 2B, are in a state after being cured by active energy rays.

[0209] The top view of unit panels 2A and 2B typically shows a rectangular shape, but this is not a limitation; it can be any desired polygon. In this embodiment, the light-emitting substrate 21 is a substrate (module) equipped with a light-emitting element for displaying images. Examples of light-emitting elements include light-emitting diodes (LEDs), laser diodes (LDs), organic electroluminescent elements, and inorganic electroluminescent elements. Among these, LEDs are preferred, and sub-millimeter LEDs or micro LEDs are particularly preferred.

[0210] In addition to the light emitter, the light emitter substrate 21 may also include the required optical components. Examples of such optical components include light diffusion components, brightness enhancement films, contrast enhancement films, viewing angle compensation films, transparent conductive films, liquid crystal polymer films, semi-transparent reflective films, and anti-scattering films.

[0211] For the surface substrate 22, in addition to glass plates and plastic plates, a protective panel preferably composed of a laminate including glass plates and plastic plates is preferred. The glass plate is not particularly limited; examples include chemically strengthened glass, alkali-free glass, quartz glass, soda-lime glass, barium-strontium glass, aluminosilicate glass, lead glass, borosilicate glass, and barium borosilicate glass. The plastic plate is also not particularly limited; examples include acrylic sheets and polycarbonate sheets.

[0212] In addition, various functional layers (transparent conductive film, metal layer, silicon dioxide layer, hard coating, anti-glare layer, etc.) can be applied to one or both sides of the aforementioned glass or plastic plate, and the aforementioned optical components can also be stacked. Furthermore, the transparent conductive film and metal layer can also be patterned.

[0213] In manufacturing the unit panel 2A, as an example, one release tab 16b of the adhesive sheet 1A is peeled off, and the exposed second adhesive layer 13 of the adhesive sheet 1A is bonded to one surface of the surface substrate 22. Next, another release tab 16a of the adhesive sheet 1A is peeled off, and the exposed first adhesive layer 12 of the adhesive sheet 1A is bonded to the light-emitting substrate 21. Alternatively, as another example, the bonding order of the surface substrate 22 and the light-emitting substrate 21 can be changed.

[0214] In manufacturing the unit panel 2B, as an example, one release tab 16b of the adhesive sheet 1B is peeled off, and the exposed adhesive layer 15 of the adhesive sheet 1B is bonded to one surface of the surface substrate 22. Next, another release tab 16a of the adhesive sheet 1B is peeled off, and the exposed adhesive layer 15 of the adhesive sheet 1B is bonded to the light-emitting substrate 21. Alternatively, as another example, the bonding order of the surface substrate 22 and the light-emitting substrate 21 can be changed.

[0215] Here, when the first adhesive layer 12 and the second adhesive layer 13 of adhesive sheet 1A, or the adhesive layer 15 of adhesive sheet 1B, are curable by active energy rays, it is preferable to irradiate the first adhesive layer 12, the second adhesive layer 13, or the adhesive layer 15 from one side (preferably from the surface substrate 22 side) after the surface substrate 22 is laminated with the adhesive laminate 11 and the light-emitting substrate 21, or after the surface substrate 22 is laminated with the adhesive layer 15 and the light-emitting substrate 21, to cure the first adhesive layer 12, the second adhesive layer 13, or the adhesive layer 15. This makes it easier to satisfy the aforementioned creep strain and results in superior adhesion.

[0216] The types and irradiation conditions of the active energy rays are the same as those mentioned above for irradiating the adhesive layer of the adhesive sheet 1B before it is attached to the substrate with active energy rays.

[0217] Preferably, after fabricating the laminated body as unit panel 2A and the laminated body as unit panel 2B in the above manner, the end faces of these laminated bodies are laser-cut to form flat surfaces, thus producing unit panels 2A and 2B. In these unit panels 2A and 2B, since the aforementioned adhesive laminate 11 or adhesive layer 15 is used, adhesive seepage from the laser-cut end faces can be suppressed. Therefore, in the splicing display formed by connecting multiple unit panels 2A and 2B, there are almost no gaps between the unit panels, thereby achieving uniform brightness and improved image quality.

[0218] Laser irradiation in laser cutting can be performed under conventional conditions. There are no particular restrictions on the type of laser used; for example, gas lasers such as carbon dioxide (CO2) lasers, TEA-CO2 lasers, and excimer lasers can be used; liquid lasers such as organic chelate compound lasers, inorganic lasers, and organic pigment lasers can be used; solid-state lasers such as YAG lasers, UV-YAG lasers, YVO4 lasers, and YLF lasers can be used; semiconductor lasers such as vertical-cavity surface-emitting lasers and quantum dot lasers can also be used. Among these, gas lasers are preferred from the perspective of obtaining a large laser output and excellent processing performance; specifically, carbon dioxide (CO2) lasers or TEA-CO2 lasers are preferred.

[0219] The wavelength of the irradiated laser is preferably 0.1~1000μm, more preferably 0.38~100μm, particularly preferably 0.78~50μm, and even more preferably 1~25μm, wherein 8~20μm is preferred. Furthermore, the laser power density is typically 1.0×10⁻⁶. 3 ~1.0×10 10 W / cm 2 Preferably 1.0×10 4 ~1.0×10 8 W / cm 2 In addition, the laser irradiation time is typically 1.0 × 10⁻⁶. -8 ~1 second, preferably 1.0×10 -5 ~1.0×10 -1 Second.

[0220] [Video Panel Display] One embodiment of the present invention provides a video wall display formed by connecting multiple unit panels 2A or 2B from the aforementioned embodiments. The connection method can be implemented using conventional methods.

[0221] Because the unit panels 2A or 2B are formed by connecting multiple laser-cut end faces to suppress adhesive seepage, there are virtually no gaps between the unit panels 2A and 2B. Therefore, the splicing display of this embodiment can achieve uniform brightness and improved image quality.

[0222] The embodiments described above are provided for ease of understanding of the present invention and are not intended to limit the invention. Therefore, the elements disclosed in the above embodiments also include all design changes or equivalents that fall within the scope of protection of the present invention.

[0223] For example, either the release tabs 16a and 16b in the adhesive sheets 1A and 1B can be omitted. Furthermore, the unit panels 2A and 2B may also have other required layers.

[0224] Furthermore, in this specification, when "X~Y" (where X and Y are arbitrary numbers) is used, unless otherwise stated, it means "X or more and Y or less," and includes the meaning of "preferably greater than X" or "preferably less than Y." Additionally, when "X or more" (where X is any number) is used, unless otherwise stated, it includes the meaning of "preferably greater than X," and when "Y or less" (where Y is any number) is used, unless otherwise stated, it also includes the meaning of "preferably less than Y."

[0225] Example The present invention will be further described in detail below through examples, etc., but the scope of the present invention is not limited by these examples, etc.

[0226] [Example 1] 1. Preparation of (meth)acrylate polymers (Meth)acrylate polymer (A) was prepared by solution polymerization of 27.5 parts by weight of n-butyl acrylate, 27.5 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of isobornyl acrylate, 5 parts by weight of N-acryloylmorpholine, and 25 parts by weight of 2-hydroxyethyl acrylate. The molecular weight of (meth)acrylate polymer (A) was determined using the method described later, and the weight-average molecular weight (Mw) was found to be 500,000.

[0227] 2. Preparation of adhesive compositions 100 parts by weight (solid content conversion value; the same below) of the (meth)acrylate polymer (A) obtained in the above process, 0.15 parts by weight of the isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as crosslinking agent (B) and 0.26 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent (C) are mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition (EX1).

[0228] Table 1 shows the proportions of the adhesive when the total amount of adhesive is set to 100 parts by mass (converted solids content). Details of the abbreviations, etc., listed in Table 1 are described below. Regarding the colorant PG1, Table 2 shows the optical properties of a liquid obtained by diluting the colorant PG1 listed in Table 1 10,000 times with ethyl acetate. The optical properties shown in Table 2 were calculated using the haze value (%) obtained according to JIS K7136:2000 and a haze meter (manufactured by Nippon Denshoku Industries, Co., LTD., product name "SH-7000"). The haze value difference (percentage points) is the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm. The average haze (%) is the average of the haze values ​​at a wavelength of 780 nm and the haze values ​​at a wavelength of 380 nm. The standard deviation of the haze value is the standard deviation of the haze value at each wavelength with a 5 nm interval within the wavelength range of 380 nm to 780 nm.

[0229] [Active Energy Ray Curing Component (D)] D1: ε-caprolactone-modified tri-(2-acryloyloxyethyl)isocyanurate (manufactured by SHIN-NAKAMURA CHEMICALCO, LTD., product name "NK Ester A-9300-1CL") D2: A mixture of ethylene oxide-modified diacrylate isocyanurate and ethylene oxide-modified tri(meth)acrylate isocyanurate (manufactured by TOAGOSEI CO.,LTD., product name "ARONIX M-315") [Photopolymerization initiator (E)] E1: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide E2: A mixture of 1-hydroxycyclohexylphenyl ketone and benzophenone in a mass ratio of 1:1. [Coloring agent] PG1: Carbon black pigments (pigments with the optical properties described in Table 2 below) PG2: Pigment (Carbon Black, manufactured by NIKKO BICS CO.,LTD., product name "NSP-VH 805 BLACK") 3. Manufacturing of adhesive sheets Using a doctor blade coater, the coating solution of the adhesive composition (EX1) obtained in the above process is coated onto the peeling treatment surface of the heavy-peel type release sheet R1, which is obtained by peeling one side of the polyethylene terephthalate film with a silicone-based release agent. The coating layer (thickness: 50 μm) is formed by heat treatment at 90°C for 1 minute, and this is used as the first laminate.

[0230] Similarly, using a doctor blade coater, the coating solution of the above adhesive composition (EX1) is coated onto the peeling treatment surface of a lightly peelable release sheet R2 obtained by peeling one side of a polyethylene terephthalate film with a silicone-based release agent, and then heat-treated at 90°C for 1 minute to form a coating layer (thickness: 50 μm), which is used as the second laminate.

[0231] Then, the coating layer side of the first laminate is attached to one side of a polyethylene terephthalate film (manufactured by TOYOBOCO.,LTD., product name "COSMOSHINE A4360", thickness: 100μm) with easy-to-adhere layers on both sides, and the coating layer side of the second laminate is attached to the other side. Then, it is cured at 23°C and 50%RH for 7 days to obtain an adhesive sheet consisting of a release sheet R2 / second adhesive layer (50μm) / core material (100μm) / first adhesive layer (50μm) / release sheet R1.

[0232] The physical properties of the aforementioned "COSMOSHINE A4360" are described below.

[0233] • Tensile strength (fracture stress) MD: 230MPa / TD: 275MPa • Elongation (MD): 140% / Elongation (TD): 92% • Dimensional change rate due to heating: MD: 1.0% / TD: 0.3% Furthermore, the thickness of each layer mentioned above was measured according to JIS K7130 using a constant pressure thickness gauge (manufactured by TECLOCK CO., LTD., product name "PG-02") (the same applies below). In addition, regarding the peel force of the release tab R1 and release tab R2 in the obtained adhesive sheet, it was confirmed that the peel force of release tab R1 is greater than that of release tab R2.

[0234] [Example 2] 100 parts by weight of (meth)acrylate polymer (A) obtained in the same manner as in Example 1, 0.15 parts by weight of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as crosslinking agent (B), 0.26 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent (C), 6.4 parts by weight of ε-caprolactone-modified tri-(2-acryloyloxyethyl)isocyanurate (D1; manufactured by SHIN-NAKAMURA CHEMICAL CO, LTD., product name "NK Ester A-9300-1CL") as active energy ray curable component (D), and 0.6 parts by weight of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (E1) as photopolymerization initiator (E) were mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition (EX2).

[0235] Using the coating solution of the adhesive composition (EX2) obtained above, an adhesive sheet with active energy ray curable properties was obtained in the same manner as in Example 1, consisting of a release sheet R2 / second adhesive layer (50 μm) / core material (100 μm) / first adhesive layer (50 μm) / release sheet R1.

[0236] [Example 3] 100 parts by weight of (meth)acrylate polymer (A) obtained in the same manner as in Example 1, 0.15 parts by weight of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as crosslinking agent (B), 0.26 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent (C), and 10 parts by weight of microparticles (light-diffusing microparticles; manufactured by Momentive Performance Materials Japan, product name "Tospearl145L", average particle size: 4.5 μm, refractive index: 1.43) composed of silicone resin (silicon-containing compound having an intermediate structure of inorganic and organic) as filler were mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition (EX3).

[0237] Using a doctor blade coater, the coating solution of the adhesive composition (EX3) obtained in the above process is coated onto the peeling treatment surface of the heavy-peel type release sheet R1, which is obtained by peeling one side of the polyethylene terephthalate film with a silicone-based release agent. The coating layer (thickness: 50 μm) is formed by heat treatment at 90°C for 1 minute, and this is used as the first laminate.

[0238] Then, the coating layer side of the first laminate was attached to one side of the polyethylene terephthalate film (manufactured by TOYOBOCO.,LTD., product name "COSMOSHINE A4360", thickness: 100μm) with easy-to-adhere layers on both sides, and the coating layer side of the second laminate prepared in Example 1 was attached to the other side. Then, it was cured at 23°C and 50%RH for 7 days to obtain an adhesive sheet composed of a release sheet R2 / second adhesive layer (50μm) / core material (100μm) / first adhesive layer (50μm) / release sheet R1.

[0239] [Example 4] 100 parts by weight of (meth)acrylate polymer (A) obtained in the same manner as in Example 1, 0.15 parts by weight of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as crosslinking agent (B), 0.26 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent (C), and 0.25 parts by weight of carbon black pigment (PG1; pigment having the optical properties described in Table 2) as colorant were mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition (EX4).

[0240] Using a doctor blade coater, the coating solution of the adhesive composition (EX4) obtained in the above process is coated onto the peeling treatment surface of the heavy-peel type release sheet R1, which is obtained by peeling one side of the polyethylene terephthalate film with a silicone-based release agent. The coating layer (thickness: 50 μm) is formed by heat treatment at 90°C for 1 minute, and this is used as the first laminate.

[0241] Then, the coating layer side of the first laminate was attached to one side of the polyethylene terephthalate film (manufactured by TOYOBOCO.,LTD., product name "COSMOSHINE A4360", thickness: 100μm) with easy-to-adhere layers on both sides, and the coating layer side of the second laminate prepared in Example 1 was attached to the other side. Then, it was cured at 23°C and 50%RH for 7 days to obtain an adhesive sheet composed of a release sheet R2 / second adhesive layer (50μm) / core material (100μm) / first adhesive layer (50μm) / release sheet R1.

[0242] [Example 5] 100 parts by weight of (meth)acrylate polymer (A) obtained in the same manner as in Example 1, 0.15 parts by weight of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as crosslinking agent (B), 0.26 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent (C), and 0.62 parts by weight of pigment (PG2; carbon black, manufactured by NIKKO BICS CO.,LTD., product name "NSP-VH805 BLACK") as colorant were mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition (EX5).

[0243] Using a doctor blade coater, the coating solution of the adhesive composition (EX5) obtained in the above process is coated onto the peeling treatment surface of the heavy-peel type release sheet R1, which is obtained by peeling one side of the polyethylene terephthalate film with a silicone-based release agent. The coating layer (thickness: 50 μm) is formed by heat treatment at 90°C for 1 minute, and this is used as the first laminate.

[0244] Then, the coating layer side of the first laminate was attached to one side of the polyethylene terephthalate film (manufactured by TOYOBOCO.,LTD., product name "COSMOSHINE A4360", thickness: 100μm) with easy-to-adhere layers on both sides, and the coating layer side of the second laminate prepared in Example 1 was attached to the other side. Then, it was cured at 23°C and 50%RH for 7 days to obtain an adhesive sheet composed of a release sheet R2 / second adhesive layer (50μm) / core material (100μm) / first adhesive layer (50μm) / release sheet R1.

[0245] [Example 6] Using a doctor blade coater, the coating solution of the adhesive composition (EX3) obtained in Example 3 was coated onto the peeling treatment surface of the lightly peelable release sheet R2, which was obtained by peeling one side of the polyethylene terephthalate film with a silicone-based release agent. The coating layer (thickness: 50 μm) was formed by heat treatment at 90°C for 1 minute, and this layer was used as the second laminate.

[0246] A coating layer side of the first laminate prepared in Example 4 is attached to one side of a polyethylene terephthalate film (manufactured by TOYOBO CO.,LTD., product name "COSMOSHINE A4360", thickness: 100μm) with easy-to-adhere layers on both sides, and a coating layer side of the second laminate prepared in Example 4 is attached to the other side. The film is then cured for 7 days at 23°C and 50%RH to obtain an adhesive sheet consisting of a release sheet R2, a second adhesive layer (50μm), a core material (100μm), a first adhesive layer (50μm), and a release sheet R1.

[0247] [Example 7] Except for using a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "lumirror #25-F65", thickness: 25 μm) as the core material, and having a first adhesive layer thickness of 87 μm and a second adhesive layer thickness of 88 μm, the adhesive sheet was manufactured in the same manner as in Example 1. That is, an adhesive sheet was manufactured having a layer consisting of a release tab R2, a second adhesive layer (88 μm), a core material (25 μm), a first adhesive layer (87 μm), and a release tab R1.

[0248] [Example 8] 100 parts by weight of (meth)acrylate polymer (A) obtained in the same manner as in Example 1, 1.5 parts by weight of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as crosslinking agent (B) and 0.26 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent (C) were mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition (EX8).

[0249] Except that the coating solution of the adhesive composition (EX8) described above is used instead of the coating solution of the adhesive composition (EX1), the adhesive sheet having a layer consisting of a release sheet R2 / second adhesive layer (50 μm) / core material (100 μm) / first adhesive layer (50 μm) / release sheet R1 is manufactured in the same manner as in Example 1.

[0250] [Example 9] 50 parts by weight of phenoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "YX7200B35", Tg: 150℃, Mw: 30,000) as epoxy resin (F) with a Tg of 50℃ or higher, 50 parts by weight of oxyalkylene epoxy resin (liquid at 23℃) (manufactured by Mitsubishi Chemical Corporation, product name "YX7400", epoxy equivalent: 440 g / eq, Tg of cured product: -69℃) as epoxy resin (G) providing a cured product with a Tg of 25℃ or lower, and 2.0 parts by weight of 4-(phenylthio)phenyldiphenylsulfonium hexafluorophosphate (cationic photopolymerization initiator) as cationic polymerization initiator (H) were mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution for epoxy resin adhesive.

[0251] Using a doctor blade coater, the above-mentioned epoxy resin adhesive coating solution is applied to the release-treated surface of a heavy-release release sheet R1, obtained by peeling one side of a polyethylene terephthalate film with a silicone-based release agent. The surface is then heated at 100°C for 2 minutes to form an adhesive layer (thickness: 50 μm) that can be cured by active energy radiation. The release-treated surface of a light-release release sheet R2, obtained by peeling one side of a polyethylene terephthalate film with a silicone-based release agent, is then bonded to this adhesive layer, resulting in an adhesive sheet consisting of release sheet R2, an adhesive layer (50 μm), and release sheet R1.

[0252] [Example 10] The mixture comprises 100 parts by weight of a polyester polymer (manufactured by Mitsubishi Chemical Corporation, product name "Nichigo-POLYESTER S-0097S55EO", a high molecular weight saturated copolyester resin with a reactive functional group (I), Tg: 1℃, weight-average molecular weight (Mw): 130,000), 2.5 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as a crosslinking agent (B), 0.25 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as a silane coupling agent, and 30 parts by weight of a mixture of ethylene oxide-modified diacrylate and ethylene oxide-modified tri(meth)acrylate as an active energy radiation curable component (D) (D2; manufactured by TOAGOSEI CO.,LTD., product name "ARONIX"). M-315”), 0.3 parts by mass of a mixture (E2) of 1-hydroxycyclohexylphenyl ketone and benzophenone in a mass ratio of 1:1 as photopolymerization initiator (E), and 0.02 parts by mass of zirconium tetraacetylacetone as catalyst (J) were mixed and stirred thoroughly. The mixture was then diluted with methyl ethyl ketone to obtain a coating solution for the polyester adhesive. Furthermore, the weight-average molecular weight (Mw) of the above polyester polymer was determined using the same method as used for determining the molecular weight of the (meth)acrylate polymer (A) described later.

[0253] Using a doctor blade coater, the above-mentioned polyester adhesive coating solution was applied to the release-treated surface of a heavy-release type release sheet R1 (obtained by releasing one side of a polyethylene terephthalate film using a silicone-based release agent), and then heated at 90°C for 1 minute to induce a crosslinking reaction, forming a coating layer (thickness: 50 μm). The release-treated surface of a light-release type release sheet R2 (obtained by releasing one side of a polyethylene terephthalate film using a silicone-based release agent) was then bonded onto this coating layer. The coating layer was then irradiated with active energy rays (ultraviolet; UV) through the release sheet R1 to cure it, thus forming an adhesive layer. The active energy irradiation conditions are as follows.

[0254] <Conditions for Irradiation by Active Energy Rays> • Use a high-pressure mercury lamp Illuminance 200mW / cm 2 Light intensity 1000 mJ / cm 2 • The UV illuminance-photometer used is the “UVPF-A1” manufactured by EYE GRAPHICS COMPANY. Then, it is cured for 7 days at 23°C and 50%RH to obtain an adhesive sheet consisting of a release sheet R2 / adhesive layer (50μm) / release sheet R1.

[0255] [Comparative Example 1] Using a doctor blade coater, a coating solution of the adhesive composition (EX1) obtained in the same manner as in Example 1 was applied to the peeling treatment surface of a heavy-peel type release sheet R1, which was obtained by peeling one side of a polyethylene terephthalate film with a silicone-based release agent. The coating layer (thickness: 100 μm) was then heat-treated at 90°C for 1 minute to form a coating layer. This layer was then used as the first laminate.

[0256] Similarly, using a doctor blade coater, the coating solution of the above adhesive composition (EX1) is coated onto the peeling treatment surface of a lightly peelable release sheet R2 obtained by peeling one side of a polyethylene terephthalate film with a silicone-based release agent, and then heat-treated at 90°C for 1 minute to form a coating layer (thickness: 100 μm), which is used as the second laminate.

[0257] Then, the coating layer of the first laminate is bonded to the coating layer of the second laminate and cured for 7 days at 23°C and 50%RH to obtain an adhesive sheet consisting of a release sheet R2 / adhesive layer (200μm) / release sheet R1.

[0258] [Comparative Example 2] 100 parts by weight of (meth)acrylate polymer (A) obtained in the same manner as in Example 1, 0.02 parts by weight of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as crosslinking agent (B) and 0.26 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent (C) were mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition (CE2).

[0259] Except that the coating solution of the adhesive composition (CE2) described above is used instead of the coating solution of the adhesive composition (EX1), an adhesive sheet having a layer consisting of a release sheet R2 / second adhesive layer (50 μm) / core material (100 μm) / first adhesive layer (50 μm) / release sheet R1 is manufactured in the same manner as in Example 1.

[0260] [Comparative Example 3] 100 parts by weight of (meth)acrylate polymer (A) obtained in the same manner as in Example 1, 1.5 parts by weight of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., product name "TAKENATE D-101E") as crosslinking agent (B) and 0.26 parts by weight of 3-epoxypropoxypropyltrimethoxysilane as silane coupling agent (C) were mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition (CE3).

[0261] Except that the coating solution of the adhesive composition (CE3) described above is used instead of the coating solution of the adhesive composition (EX1), an adhesive sheet having a layer consisting of a release sheet R2 / second adhesive layer (50 μm) / core material (100 μm) / first adhesive layer (50 μm) / release sheet R1 is manufactured in the same manner as in Example 1.

[0262] The aforementioned weight-average molecular weight (Mw) is the weight-average molecular weight converted from polystyrene determined using gel permeation chromatography (GPC) under the following conditions (GPC determination).

[0263] <Measurement Conditions> • GPC measuring apparatus: Manufactured by TOSOH CORPORATION, HLC-8020 • GPC column (passes through in the following order): Manufactured by TOSOH CORPORATION TSK guard column HXL-H TSK gel GMHXL (×2) TSK gel G2000HXL • Solvent for determination: Tetrahydrofuran • Measurement temperature: 40℃ [Experimental Example 1] (Determination of Gel Fraction) For Examples 1-8 and Comparative Examples 2-3, the first and second laminates obtained during the manufacture of the adhesive sheet were cured for 7 days at 23°C and 50% RH. Then, the first and second laminates were cut to 80mm x 80mm dimensions, and their adhesive layers (first adhesive layer and second adhesive layer) were wrapped in a polyester sieve (sieve aperture size 200). Their mass was weighed using a precision balance, and the mass of the sieve alone was subtracted to calculate the mass of the adhesive itself. Furthermore, for Examples 9-10 and Comparative Example 1, the manufactured adhesive sheet was cut to 80mm x 80mm dimensions, and the mass of its adhesive layer (a single adhesive layer) was calculated in the same manner as above. This mass is designated as M1.

[0264] Next, the adhesive wrapped around the aforementioned polyester screen was immersed in ethyl acetate for 24 hours at room temperature (23°C). The adhesive was then removed and air-dried at 23°C and 50% RH for 24 hours, followed by drying in an oven at 80°C for 12 hours. After drying, its mass was measured using a precision balance, and the mass of the screen alone was subtracted to calculate the mass of the adhesive itself. This mass is designated as M2. The gel fraction (%) is expressed as (M2 / M1) × 100. The results are shown in Table 3.

[0265] In addition, regarding the adhesive sheets of Examples 2 and 9, the gel fraction (after UV) after irradiating the adhesive layer with active energy rays (ultraviolet; UV) through the release sheet R2 was also measured. The irradiation conditions of the active energy rays were the same as those used in Example 10 to cure the adhesive layer.

[0266] [Experimental Example 2] (Determination of Creep Strain) The adhesive laminates consisting of a first adhesive layer, a core material, and a second adhesive layer from the adhesive sheets of Examples 1-8 and Comparative Examples 2-3, as well as the adhesive layers from the adhesive sheets of Examples 9-10 and Comparative Example 1, were punched out to form cylinders with a diameter of 8 mm, which were used as samples. Additionally, for the adhesive sheets of Examples 2 and 9, adhesive sheets whose adhesive layers were cured by active energy radiation in the same manner as in Test Example 1 were used.

[0267] For the above samples, according to JIS K7244-6, the strain (creep strain) (%) under a 10 kPa pressure applied for 600 seconds was determined using a viscoelasticity measuring apparatus (manufactured by Anton Paar, product name "MCR302") and the torsional shear method. The results are shown in Table 3.

[0268] Measurement frequency: 1Hz Measurement temperature: 23℃ [Experimental Example 3] (Tension Test) The adhesive laminates consisting of a first adhesive layer, a core material, and a second adhesive layer from the adhesive sheets of Examples 1-8 and Comparative Examples 2-3, as well as the adhesive layers from the adhesive sheets of Examples 9-10 and Comparative Example 1, were cut into samples (MD, TD) with a width of 10 mm and a length of 75 mm. Additionally, for the adhesive sheets of Examples 2 and 9, adhesive sheets after the adhesive layer had been cured by active energy radiation in the same manner as in Test Example 1 were used.

[0269] The samples were placed in a tensile testing machine (manufactured by ORIENTEC CO.,LTD., product name "TENSILON") with a measurement area of ​​10 mm wide × 25 mm long (in the elongation direction). The samples were elongated at a tensile speed of 200 mm / min under conditions of 23°C and 50% RH. The samples were elongated until fracture, and the elongation at break (%) and fracture stress (MPa) were measured. This measurement was performed on both MD and TD samples. The results are shown in Table 3.

[0270] Furthermore, the ratio of the elongation at break of MD to the elongation at break of TD (MD / TD) and the ratio of the fracture stress of MD to the fracture stress of TD (MD / TD) were calculated. The results are shown in Table 3.

[0271] [Experimental Example 4] (Determination of Adhesion) Release sheet R2 was peeled from the adhesive sheets manufactured in Examples 1-8 and Comparative Examples 2-3. The exposed second adhesive layer of the adhesive laminate was then bonded to the easy-adhesive layer of a polyethylene terephthalate (PET) film (manufactured by TOYOBO CO.,LTD., product name "COSMOSHINE A4360", thickness: 100 μm) having an easy-adhesive layer, resulting in a laminate of release sheet R1 / first adhesive layer / core material / second adhesive layer / PET film. The resulting laminate was cut into pieces 25 mm wide and 100 mm long.

[0272] Under conditions of 23°C and 50%RH, the release sheet R1 was peeled from the aforementioned laminate. The exposed first adhesive layer of the adhesive laminate was then attached to soda-lime glass (manufactured by NIPPON SHEET GLASS CO.,LTD.), and pressurized at 0.5 MPa and 50°C for 20 minutes using a pressurizer manufactured by KURIHARASEISAKUSHO Co.,Ltd. The sample was then left to stand at 23°C and 50%RH for 24 hours. The adhesion of the first adhesive layer (before UV exposure; N / 25 mm) was then measured using a tensile testing machine (ORIENTEC Co., Ltd., product name "TENSILON") at a peel speed of 300 mm / min and a peel angle of 180 degrees. Conditions not described here were measured according to JIS Z0237:2022. The results are shown in Table 3.

[0273] For the second adhesive layer of the adhesive sheets manufactured in Examples 1-8 and Comparative Examples 2-3, the adhesion (before UV; N / 25mm) was also measured in the same manner as described above. The results are shown in Table 3.

[0274] Furthermore, the release sheet R2 was peeled from the adhesive sheets of Examples 9-10 and Comparative Example 1, and the exposed adhesive layer was adhered to the easy-adhesive layer of a polyethylene terephthalate (PET) film (manufactured by TOYOBO CO.,LTD., product name "COSMOSHINE A4360", thickness: 100 μm) having an easy-adhesive layer, to obtain a laminate of release sheet R1 / adhesive layer / PET film. The obtained laminate was cut into pieces 25 mm wide and 100 mm long.

[0275] Under conditions of 23°C and 50%RH, the release sheet R1 was peeled from the above-described laminate. The exposed adhesive layer was then attached to soda-lime glass (manufactured by NIPPON SHEET GLASS CO.,LTD.), and pressurized at 0.5 MPa and 50°C for 20 minutes using a pressurizer manufactured by KURIHARA SEISAKUSHO Co.,Ltd. It was then left to stand at 23°C and 50%RH for 24 hours, and this was used as a sample. For this sample, the adhesion (before UV; N / 25 mm) was measured in the same manner as described above. The results are shown in Table 3.

[0276] For the adhesive sheets of Examples 2 and 9, they were attached to soda-lime glass in the same manner as described above and pressurized using a pressure heat exchanger. Then, the adhesive layer was irradiated with active energy rays (ultraviolet; UV) through the PET film described above. The adhesion (after UV) was then measured after 24 hours of storage in the same manner as described above. The irradiation conditions of the active energy rays were the same as those in Test Example 1. The results are shown in Table 3.

[0277] [Experimental Example 5] (Determination of Total Transmittance) The adhesive laminate / adhesive layer of the adhesive sheet manufactured in the examples and comparative examples was bonded to glass and used as the sample for testing. Based on the background measurement using glass, the total transmittance (%) of the above-mentioned sample was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SH-7000") according to JIS K7361-1:1997. The results are shown in Table 3.

[0278] In addition, for the adhesive sheets of Examples 2 and 9, the adhesive layer was irradiated with active energy rays (ultraviolet; UV) through the glass of the above-mentioned test sample, and the total transmittance (%) was measured in the same manner as above. The results were the same as those of the above-mentioned measurement results. The irradiation conditions of the active energy rays were the same as those of Test Example 1.

[0279] [Experimental Example 6] (Determination of Haze Value) The adhesive laminate / adhesive layer of the adhesive sheet manufactured in the examples and comparative examples was bonded to glass and used as the test sample. Based on the background measurement using glass, the haze value (%) of the above-mentioned test sample was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SH-7000") according to JIS K7361-1:2000. The results are shown in Table 3.

[0280] In addition, for the adhesive sheets of Examples 2 and 9, the adhesive layer was irradiated with active energy rays (ultraviolet; UV) through the glass of the above-mentioned test sample, and the haze value (%) was measured in the same manner as above. The results were the same as the results of the above-mentioned measurements. The irradiation conditions of the active energy rays were the same as those of Test Example 1.

[0281] [Experimental Example 7] (Determination of Dimensional Change Rate) The adhesive laminates consisting of a first adhesive layer, a core material, and a second adhesive layer from the adhesive sheets of Examples 1-8 and Comparative Examples 2-3, as well as the adhesive layers from the adhesive sheets of Examples 9-10 and Comparative Example 1, were cut into samples (MD, TD) with a width of 5 mm and a length of 30 mm. Additionally, for the adhesive sheets of Examples 2 and 9, adhesive sheets after the adhesive layer had been cured by active energy radiation in the same manner as in Test Example 1 were used.

[0282] Using a thermomechanical analysis apparatus (NETZSCH Japan KK, apparatus name "TMS4000SA"), the sample was placed with a chuck spacing of 20 mm, heated from 25 °C to 130 °C at a heating rate of 5 °C / min, and then cooled to room temperature at a cooling rate of 5 °C / min (heat treatment process). The displacement along the long side before and after the heat treatment process was then measured, and the rate of change (expressed as a percentage of the displacement relative to the 20 mm chuck spacing) was taken as the dimensional change rate (%). The results of the dimensional change rate (%) measurements in the MD and TD directions are shown in Table 3. Furthermore, sample shrinkage was set as negative values ​​and elongation as positive values.

[0283] [Experimental Example 8] (Evaluation of Laser Cutting Machinability) The adhesive sheets manufactured in the examples and comparative examples were cut into sizes of 100mm in length and 100mm in width, and used as samples. In addition, for the adhesive sheets of Examples 2 and 9, adhesive sheets after the adhesive layer was cured by active energy rays in the same manner as in Test Example 1 were used.

[0284] The ends of each side of the sample obtained above were laser-cut using a 30W CO2 laser system (manufactured by Universal Laser Systems, Inc., Scottsdale, Arizona, USA, product name "VLS2.30"), with 500μm removed from each end face. The laser cutting conditions are as follows.

[0285] • Mode: Vector Light · Output 5% • Speed ​​4% 150 PPI After the laser cutting process described above, the end faces of the samples were visually inspected to determine whether adhesive seepage had occurred, and the laser cutting processability was evaluated according to the following criteria. The results are shown in Table 3.

[0286] No adhesive seepage was observed on the end face of the sample after laser cutting.

[0287] ...Adhesive seepage was observed on the end face of the sample after laser cutting.

[0288] [Experimental Example 9] (Evaluation of Fit) For the laser-cut sample of Example 8, the end face of the sample was visually inspected, and it was determined whether there was any lifting or peeling at the interface between the glass plate and the adhesive layer. If there was no lifting or peeling, the end face of the sample was rubbed 10 times from bottom to top with a finger to check for lifting or peeling again, and the adhesion was evaluated according to the following criteria. The results are shown in Table 3.

[0289] ◎…No floating or peeling occurred.

[0290] ○…Slight lifting and peeling occurred near the end face of the sample, but this does not affect its actual use.

[0291] ×... showed significant bubbling and peeling.

[0292] [Table 1] [Table 2] [Table 3] As shown in Table 3, the adhesive sheets manufactured in the examples exhibit excellent laser cutting machinability. Furthermore, the adhesive sheets manufactured in Examples 1-7, 9, and 10 also demonstrate excellent adhesion to the adhered objects even after laser cutting.

[0293] Industrial applicability The adhesive sheet of the present invention can be suitably used to manufacture unit panels constituting a video wall display.

Claims

1. An adhesive sheet for manufacturing unit panels constituting a video wall display, characterized in that, have: First adhesive layer, Second adhesive layer, and The core material disposed between the first adhesive layer and the second adhesive layer According to the torsional shear method of JIS K7244-6, when a pressure of 10 kPa is applied to the adhesive laminate consisting of the first adhesive layer, the core material and the second adhesive layer at a temperature of 23°C and a frequency of 1 Hz for 600 seconds, the strain is less than 120%.

2. An adhesive sheet for manufacturing unit panels constituting a video wall display, characterized in that, It has an adhesive layer. According to the torsional shear method of JIS K7244-6, the strain of the adhesive layer when subjected to a pressure of 10 kPa for 600 seconds at a temperature of 23°C and a frequency of 1 Hz is less than 120%.

3. The adhesive sheet according to claim 1 or 2, characterized in that, The adhesive constituting the adhesive layer has a gel content of 20% or more and 99% or less.

4. An adhesive sheet for manufacturing unit panels constituting a video wall display, characterized in that, have: First adhesive layer, Second adhesive layer, and The core material disposed between the first adhesive layer and the second adhesive layer According to the torsional shear method of JIS K7244-6, when a pressure of 10 kPa is applied to the adhesive laminate composed of the first adhesive layer, the core material and the second adhesive layer at a temperature of 23°C and a frequency of 1 Hz for 600 seconds, the strain is less than 120%. The adhesion of the first adhesive layer and the second adhesive layer to the soda-lime glass is greater than 5N / 25mm.

5. An adhesive sheet for manufacturing unit panels constituting a video wall display, characterized in that, have: First adhesive layer, Second adhesive layer, and The core material disposed between the first adhesive layer and the second adhesive layer The gel fractions of the adhesives constituting the first adhesive layer and the adhesives constituting the second adhesive layer are both 30% or more and 99% or less. The adhesion of the first adhesive layer and the second adhesive layer to the soda-lime glass is greater than 5N / 25mm.

6. The adhesive sheet according to claim 4, characterized in that, The gel fractions of the adhesives constituting the first adhesive layer and the adhesives constituting the second adhesive layer are 30% or more and 99% or less, respectively.

7. The adhesive sheet according to any one of claims 1, 4, and 5, characterized in that, The adhesives constituting the first adhesive layer and the second adhesive layer are acrylic adhesives.

8. The adhesive sheet according to claim 2, characterized in that, The adhesive that constitutes the adhesive layer is an adhesive containing epoxy resin or a polyester-based adhesive.

9. The adhesive sheet according to any one of claims 1, 4, and 5, characterized in that, The thicknesses of the first adhesive layer and the second adhesive layer are respectively 1 μm or more and 100 μm or less. The thickness of the core material is more than 1 μm and less than 300 μm.

10. The adhesive sheet according to claim 2, characterized in that, The thickness of the adhesive layer is more than 1 μm and less than 100 μm.

11. The adhesive sheet according to any one of claims 1, 4, and 5, characterized in that, The core material is made of a plastic film.

12. The adhesive sheet according to any one of claims 1, 2, 4 and 5, characterized in that, It has two release tabs that protect the adhesive surface of the adhesive layer, one of which is located on the outermost layer of one side of the adhesive tab, and the other release tab is located on the outermost layer of the other side of the adhesive tab.

13. A unit panel, which constitutes a video wall display, characterized in that, An adhesive laminate comprising the first adhesive layer, the core material, and the second adhesive layer in any one of claims 1, 4, and 5.

14. A unit panel, which constitutes a video wall display, characterized in that, It has an adhesive layer as described in claim 2.

15. The unit panel according to claim 13 or 14, characterized in that, The end face of the unit panel is formed by laser cutting.

16. The unit panel according to claim 13, characterized in that, It has a surface substrate and a light-emitting substrate. The unit panel is formed by bonding the surface substrate or a laminate having the surface substrate to the light-emitting substrate or a laminate having the light-emitting substrate through the adhesive laminate.

17. The unit panel according to claim 14, characterized in that, It has a surface substrate and a light-emitting substrate. The unit panel is formed by bonding the surface substrate or a laminate having the surface substrate to the light-emitting substrate or a laminate having the light-emitting substrate through the adhesive layer.

18. The unit panel according to claim 16 or 17, characterized in that, The light-emitting substrate has a sub-millimeter light-emitting diode or a micro light-emitting diode as its light-emitting element.

19. A video wall display formed by connecting multiple unit panels as described in claim 13 or 14.

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