Adhesive sheet

Abstract

To provide an adhesive sheet which can be used in transferring an electronic component, can contribute to improving production costs, is excellent in positioning precision of the electronic component and fixability and releasability to an adhesive sheet of the electronic component and can prevent contamination of the electronic component and damage to the electronic component.SOLUTION: There is provided an adhesive sheet which has an adhesive laminate having a first adhesive layer and a second adhesive layer disposed on one surface of the first adhesive layer, wherein the first adhesive layer is constituted of an active energy ray-curable adhesive A and the second adhesive layer is constituted of an active energy ray-curable adhesive B, the adhesive laminate contains an ultraviolet absorbing compound having an ultraviolet absorbing structure and the amount of the ultraviolet absorbing structure on the outer surface of the second adhesive layer and the amount of the ultraviolet absorbing structure on the outer surface of the first adhesive layer satisfy the following expression: the amount of the ultraviolet absorbing structure on the outer surface of the first adhesive layer / the amount of the ultraviolet absorbing structure on the outer surface of the second adhesive layer≤0.3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to an adhesive sheet. [Background technology]

[0002] Conventionally, when transferring electronic components placed on a predetermined material to another material, the electronic components are received using an adhesive sheet, and then the electronic components are transferred to the other material. For example, when incorporating an LED chip into a device, the LED chip formed on the material is first transferred onto an adhesive sheet, received, and then transferred from the adhesive sheet to the predetermined device or material, thereby transporting the LED chip.

[0003] In the transportation of electronic components as described above, there is a need to improve production costs (reduction of required materials, reduction of required time and man-hours, etc.), ensure accurate positioning of electronic components, achieve both fixability and detachability of electronic components to adhesive sheets, prevent contamination of electronic components, and prevent damage to electronic components. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5875850 [Patent Document 2] Patent No. 6053756 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention was made to solve the above-mentioned conventional problems, and its objective is to provide an adhesive sheet that can be used when transporting electronic components, which can contribute to improving production costs, has excellent positional accuracy of electronic components, and provides excellent fixation and peelability of electronic components to the adhesive sheet, and enables prevention of contamination and damage to electronic components. [Means for solving the problem]

[0006] [1] The adhesive sheet of the present invention comprises an adhesive laminate having a first adhesive layer and a second adhesive layer disposed on one side of the first adhesive layer, wherein the first adhesive layer is composed of an active energy ray curable adhesive A, and the second adhesive layer is composed of an active energy ray curable adhesive B, and the adhesive laminate contains an ultraviolet absorbing compound having an ultraviolet absorbing structure, and the amount of ultraviolet absorbing structure on the outer surface of the second adhesive layer and the amount of ultraviolet absorbing structure on the outer surface of the first adhesive layer satisfy the relationship of the following formula. Amount of UV-absorbing structure on the outer surface of the first adhesive layer / Amount of UV-absorbing structure on the outer surface of the second adhesive layer ≤ 0.3 [2] The adhesive sheet in [1] above may have a light transmittance of 50% or less at a wavelength of 355 nm. [3] In the adhesive sheet described in [1] or [2] above, the active energy ray curable adhesive B may contain the base polymer having the ultraviolet absorbing structure described above. [4] In the adhesive sheets described in [1] to [3] above, the HSP distance between the base polymer contained in the active energy ray curable adhesive A and the ultraviolet absorbing compound contained in the second adhesive layer may be 8 or more. [5] In the adhesive sheets described in [1] to [4] above, the active energy ray curable adhesive B may contain a crosslinking agent a having a functional group that can interact with the functional group of the ultraviolet absorbing compound. [6] In the adhesive sheets described in [1] to [5] above, the initial indentation modulus of the second adhesive layer at 23°C may be 4 MPa or less. [7] In the adhesive sheets described in [1] to [6] above, the second adhesive layer is 460 mJ / cm 2 The layer may have an indentation modulus of 150 MPa or more at 23°C after irradiation with ultraviolet light. [8] In the adhesive sheets described in [1] to [7] above, the first adhesive layer is 460 mJ / cm 2 The layer may also have an indentation modulus of 100 MPa or more at 23°C after irradiation with ultraviolet light. [9] The pressure-sensitive adhesive sheet according to any one of [1] to [8] above may have a thickness of 60 µm or less. Effects of the Invention

[0007] According to the present invention, there can be provided a pressure-sensitive adhesive sheet that can be used when transferring electronic components, can contribute to reducing production costs, is excellent in positional accuracy of electronic components, and in fixing properties and peelability of electronic components with respect to the pressure-sensitive adhesive sheet, and enables prevention of contamination of electronic components and prevention of damage to electronic components. Brief Description of Drawings

[0008] [Figure 1] (a) is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention. (b) is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to another embodiment of the present invention. Mode for Carrying Out the Invention

[0009] A. Overview of adhesive sheets Figure 1(a) is a schematic cross-sectional view of an adhesive sheet according to one embodiment of the present invention. The adhesive sheet 100 according to this embodiment comprises an adhesive laminate 10. The adhesive laminate 10 comprises a first adhesive layer 11 and a second adhesive layer 12 disposed on one side of the first adhesive layer. The adhesive laminate 10 contains an ultraviolet absorbing compound having an ultraviolet absorbing structure. The first adhesive layer 11 is composed of an active energy ray curable adhesive A. The second adhesive layer 12 is composed of an active energy ray curable adhesive B. Figure 1(b) is a schematic cross-sectional view of an adhesive sheet according to one embodiment of the present invention. The adhesive sheet 200 according to this embodiment further comprises a base material 20, and the adhesive laminate 10 is disposed on at least one side of the base material 20. Preferably, the second adhesive layer 12 is disposed on the side opposite to the base material 20 of the first adhesive layer. Although not shown, the adhesive sheet of the present invention may be provided with a release liner on the outside of the adhesive laminate for the purpose of protecting the adhesive surface until it is put into use. Furthermore, the adhesive sheet may further include any other suitable layer, as long as the effects of the present invention are obtained. In one embodiment, the adhesive laminate is placed directly on the substrate (i.e., without any other layers). In the present invention, as described later, the adherend can be easily peeled off due to the decrease in adhesive strength and the generation of strain associated with the increased modulus of elasticity of the second adhesive layer. Therefore, it is possible to construct the adhesive sheet without providing any layer other than the adhesive layer (a so-called separation layer) for separating the adherend from the adhesive sheet.

[0010] In one embodiment, the adhesive sheet is used for transferring electronic components. More specifically, the adhesive sheet can be used for transporting electronic components, including receiving the electronic components by a laser lift-off process and then peeling them off by laser irradiation. Examples of electronic components include mini-LEDs and micro-LEDs. In one embodiment, the adhesive sheet can be used to transfer a plurality of adherends (e.g., electronic components such as LED chips) arranged on a substrate (e.g., a hard substrate such as a sapphire substrate) to the adhesive sheet; and to transfer the adherends on the adhesive sheet to another member. In this case, it is preferable that the second adhesive layer be on the adherend side. In one embodiment, the transfer of electronic components from the substrate to the adhesive sheet can be performed by a process that includes irradiating the substrate / electronic component interface with laser light, i.e., a laser lift-off process. According to the present invention, since the electronic components can be placed on the adhesive sheet in a desirable state, such as preventing the electronic components from tilting, it is possible to preferably receive the electronic components by a laser lift-off process, for example. Furthermore, when a laser lift-off process is employed, it is possible to prevent contaminants generated from the adhesive layer due to the effects of laser light irradiation from adhering to the electronic component being adhered to.

[0011] Transfer from an adhesive sheet to another component can be performed by laser irradiation. In this invention, the adhesive laminate contains an ultraviolet-absorbing compound, which enables the delamination of the adherend (electronic component) by laser irradiation. More specifically, by irradiating the adhesive laminate with laser light, the ultraviolet-absorbing compound is heated, causing strain in the adhesive laminate (essentially the second adhesive layer), and as a result, delamination occurs in the area irradiated with laser light. According to this invention, since strain can be generated in the adhesive laminate over a minute area as described above, even when processing small electronic components (e.g., 50 μm square), the electronic components can be easily delaminated. Using such an adhesive sheet eliminates the need to clean the electronic components after delamination. Furthermore, even when small electronic components that require delamination and small electronic components that do not require delamination are temporarily fixed next to each other, only the small electronic components that require delamination can be delaminated, preventing the unwanted detachment of small electronic components.

[0012] In the above-described adhesive sheet, the amount of ultraviolet absorption structure on the outer surface of the first adhesive layer and the amount of ultraviolet absorption structure on the outer surface of the second adhesive layer satisfy the following relationship. Note that the outer surface of the first adhesive layer refers to the surface of the first adhesive layer opposite to the second adhesive layer, and the surface of the second adhesive layer refers to the surface of the second adhesive layer opposite to the first adhesive layer. Amount of UV-absorbing structure on the outer surface of the first adhesive layer / Amount of UV-absorbing structure on the outer surface of the second adhesive layer ≤ 0.3

[0013] In this specification, the term "ultraviolet absorption structure" includes both ultraviolet absorption structures contained in low-molecular-weight compounds (so-called ultraviolet absorbers) and ultraviolet absorption structures bonded to high-molecular-weight compounds (polymers). For convenience, in this specification, low-molecular-weight compounds and high-molecular-weight compounds containing ultraviolet absorption structures are collectively referred to as ultraviolet absorption compounds.

[0014] In this invention, the amount of ultraviolet absorption structure is defined as the amount identified by FT-IR analysis. The amount of ultraviolet absorption structure can be identified by the following method. i) Identify the ultraviolet absorption structure in the adhesive layer sample using a predetermined method. ii) For the identified UV-absorbing structures, a calibration curve of (amount of UV-absorbing structure) versus (intensity of peaks derived from UV-absorbing structures) is obtained by FT-IR measurement using another group of adhesive layer samples with known UV-absorbing structure content. iii) The intensity of the peak derived from the ultraviolet absorption structure in the adhesive layer sample is determined by FT-IR measurement, and the amount of ultraviolet absorption structure is identified based on the calibration curve described above. In the above i), the ultraviolet absorption structure can be identified by any appropriate analytical method. For example, FT-IR analysis, NMR analysis, TOF-SIMS, Raman spectroscopy, and combinations thereof can be used. If the formulation for adhesive layer formation is known, structural identification by analysis may be omitted. Furthermore, in (ii) above, the calibration curve can be obtained based on the ratio of the peak intensity derived from the UV absorption structure to the peak intensity derived from the base polymer (e.g., acrylic polymer) constituting another adhesive layer sample. For example, the peak intensity may be the peak intensity at the maximum absorption wavenumber for each compound / structure.

[0015] Furthermore, the amount of UV absorption structure can also be determined by NMR analysis, TOF-SIMS, Raman spectroscopy, etc.

[0016] In this invention, by using two or more adhesive layers and unevenly distributing the ultraviolet-absorbing compound in the second adhesive layer on the adherend side, the above effect of laser irradiation can be concentrated on the surface where peeling is desired. As a result, peelability can be preferably achieved by low-energy laser irradiation. Furthermore, when laser light is irradiated, the decomposition of the adhesive layer in areas with low contribution to peelability is suppressed, resulting in a significant effect in preventing contaminants generated from the adhesive laminate from adhering to the electronic component that is the adherend.

[0017] As described above, the adhesive laminate (i.e., the first adhesive layer and the second adhesive layer) is composed of an active energy ray-curable adhesive. When an adhesive sheet containing an active energy ray-curable adhesive is irradiated with active energy rays, the adhesive strength of the entire adhesive laminate decreases. After irradiating the entire adhesive laminate of the adhesive sheet to which the adherend (electronic component) is attached with active energy rays to reduce the adhesive strength, irradiating it with laser light as described above can prevent adhesive residue after peeling. Using such an adhesive sheet eliminates the need to clean the electronic component after peeling. Furthermore, by forming an adhesive laminate containing an active energy ray-curable adhesive, the laser output required for peeling can be reduced. Since the adhesive sheet of the present invention exhibits peelability with low-power laser light, using this adhesive sheet can reduce damage to the adherend (electronic component) during peeling and prevent damage to the electronic component. In addition, since peelability can be achieved with laser light of an output that does not cause decomposition (thermal decomposition) of the adhesive laminate itself, contamination of the adherend (electronic component) by adhesive layer decomposition products can be prevented. Examples of active energy rays include gamma rays, ultraviolet rays, visible light, infrared rays (thermal rays), radio waves, alpha rays, beta rays, electron beams, plasma streams, ionization rays, and particle beams. Ultraviolet rays are preferred.

[0018] The light transmittance of the adhesive sheet of the present invention at a wavelength of 355 nm is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less. Within this range, the laser output during peeling can be reduced. The light transmittance of the adhesive sheet refers to the light transmittance in the thickness direction of the adhesive sheet and is measured for all constituent layers of the adhesive sheet. In the present invention, the light transmittance of the adhesive sheet at a wavelength of 355 nm can be controlled by adjusting the content ratio of the ultraviolet absorbing compound contained in the adhesive laminate. Furthermore, the light transmittance of the adhesive sheet at a wavelength of 355 nm can also be controlled by the composition of the base polymer and photopolymerization initiator constituting the adhesive layer. For example, the light transmittance of the adhesive sheet at a wavelength of 355 nm can be controlled by the type and amount of photopolymerization initiator contained in the adhesive layer, and in particular by the compatibility between the photopolymerization initiator and the base polymer.

[0019] The visible light transmittance of the above adhesive sheet is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. Within this range, an adhesive sheet can be obtained in which the object to be peeled off can be clearly seen through the adhesive sheet when peeling off the object by laser light irradiation. A higher visible light transmittance of the adhesive sheet is preferable, but its upper limit is, for example, 95% (preferably 100%).

[0020] The haze value of the above adhesive sheet is preferably 70% or less, and more preferably 65% ​​or less. Within this range, an adhesive sheet can be obtained in which the object to be peeled off can be clearly seen through the adhesive sheet when peeling off the object by laser light irradiation. A lower haze value of the adhesive sheet is preferable, but its lower limit is, for example, 0.1%.

[0021] The initial adhesive strength A at 23°C immediately after the second adhesive layer of the above-mentioned adhesive sheet is attached to the stainless steel plate is preferably 0.1N / 20mm to 15N / 20mm, and more preferably 0.5N / 20mm to 10N / 20mm. Within this range, an adhesive sheet that can hold the adherend well can be obtained. The adhesive strength is measured in accordance with JIS Z 0237:2000. Specifically, the adhesive sheet is attached to the stainless steel plate (arithmetic mean surface roughness Ra: 50±25nm) by one back-and-forth motion of a 2kg roller, left at 23°C for 30 minutes, and then the adhesive sheet is peeled off and measured under conditions of a peeling angle of 180° and a peeling speed (tensile speed) of 300mm / min. The adhesive strength of the adhesive layer changes with irradiation of active energy rays and laser light, but in this specification, "initial adhesive strength" means the adhesive strength before irradiation with active energy rays and laser light.

[0022] In one embodiment, the second adhesive layer of the adhesive sheet is attached to a stainless steel plate, and 300 mJ / cm² is applied. 2 The adhesive strength B (also called cured adhesive strength B) at 23°C after irradiation with ultraviolet light is preferably 0.2 N / 20 mm or less, more preferably 0.01 N / 20 mm to 0.2 N / 20 mm, and more preferably 0.02 N / 20 mm to 0.15 N / 20 mm. Within this range, an adhesive sheet with minimal adhesive residue can be obtained. The above ultraviolet irradiation is performed, for example, using an ultraviolet irradiation device (manufactured by Nitto Seiki Co., Ltd., product name "UM-810") with ultraviolet light from a high-pressure mercury lamp (characteristic wavelength: 365 nm, integrated light intensity: 300 mJ / cm²). 2 This is done by irradiating the adhesive layer with a light source.

[0023] The rate of decrease of the cured adhesive strength B relative to the initial adhesive strength A is preferably 90% or more, and more preferably 95% or more. Within this range, an adhesive sheet with excellent peelability can be obtained. The rate of decrease (%) can be calculated using the formula (initial adhesive strength A - cured adhesive strength B) / initial adhesive strength A × 100.

[0024] The initial adhesive strength A' at 23°C immediately after the first adhesive layer of the adhesive sheet is attached to the stainless steel plate is preferably 0.1N / 20mm to 15N / 20mm, and more preferably 0.5N / 20mm to 10N / 20mm.

[0025] In one embodiment, the first adhesive layer of the adhesive sheet is attached to a stainless steel plate, and 300 mJ / cm² is applied. 2 The adhesive strength B' (also called the adhesive strength after curing) at 23°C after irradiation with ultraviolet light is preferably 0.2 N / 20 mm or less, more preferably 0.01 N / 20 mm to 0.2 N / 20 mm, and more preferably 0.02 N / 20 mm to 0.15 N / 20 mm.

[0026] The thickness of the adhesive sheet is preferably 1 μm to 300 μm, and more preferably 5 μm to 200 μm. In one embodiment, the thickness of the adhesive sheet is 60 μm or less. In the present invention, by unevenly distributing the ultraviolet absorbing compound in a two-layer structure, it is possible to make an adhesive sheet with a relatively thick thickness.

[0027] B. Adhesive laminate As described above, the amount of ultraviolet absorption structure on the outer surface of the first adhesive layer and the amount of ultraviolet absorption structure on the outer surface of the second adhesive layer satisfy the following relationship. Amount of UV-absorbing structure on the outer surface of the first adhesive layer / Amount of UV-absorbing structure on the outer surface of the second adhesive layer ≤ 0.3 The ratio (amount of UV-absorbing structure on the outer surface of the first adhesive layer / amount of UV-absorbing structure on the outer surface of the second adhesive layer) is preferably 0.2 or less, more preferably 0.1 or less, even more preferably 0.08 or less, particularly preferably 0.05 or less, and most preferably 0. Within this range, the above effect becomes significant. Note that the UV-absorbing compound present in the first adhesive layer may be a migration product from the second adhesive layer.

[0028] The thickness of the adhesive laminate is preferably 1 μm to 100 μm, more preferably 2 μm to 80 μm, even more preferably 3 μm to 60 μm, and particularly preferably 5 μm to 40 μm. In one embodiment, the thickness of the adhesive laminate is 60 μm or less. In the present invention, by forming an adhesive layer with two or more layers and unevenly distributing the ultraviolet absorbing compound, it is possible to create an adhesive laminate with a relatively thick thickness.

[0029] B-1. First adhesive layer As described above, the first adhesive layer is composed of an active energy ray-curable adhesive A. In one embodiment, an active energy ray-curable adhesive (A1) is used as the active energy ray-curable adhesive A, comprising a base polymer and an active energy ray-reactive compound (monomer or oligomer) that can bond to the base polymer. In another embodiment, an active energy ray-curable adhesive (A2) is used, comprising an active energy ray-reactive polymer as the base polymer. Compounds described in Section B-2 below may be used as the base polymer, the active energy ray-reactive compound that can bond to the base polymer, and the active energy ray-reactive polymer. In one embodiment, an adhesive containing an acrylic polymer as the base polymer is used. Furthermore, the active energy ray-curable adhesive A may further contain any suitable additives as needed. Additives such as crosslinking agents exemplified in Section B-2 below may be used. It is preferable not to add an ultraviolet absorber to the active energy ray-curable adhesive A during preparation. Furthermore, it is preferable that the base polymer contained in the active energy ray curing adhesive A does not have an ultraviolet absorption structure.

[0030] In one embodiment, the HSP distance between the base polymer (preferably an acrylic polymer) contained in the active energy ray curable adhesive A constituting the first adhesive layer and the ultraviolet absorbing compound contained in the second adhesive layer is preferably 8 or more, and more preferably 10 or more. In this specification, HSP (solubility parameter) is defined as Hildebrand's solubility parameter δ, with the dispersion term δd , a polar term δ p , and a hydrogen bonding term δ h is divided into three components and represented in three-dimensional space, with the relationship δ2=δd 2 +δp 2 +δh 2 holds true. The dispersion term δ d represents the effect due to dispersion forces, the polar term δ p represents the effect due to dipole-dipole forces, and the hydrogen bonding term δ h represents the effect due to hydrogen bonding forces. The HSP distance Ra between two substances is calculated from the difference Δδ d in dispersion term, the difference Δδ p in polar term, and the difference Δδ h in hydrogen bonding term between the two substances, and expressed as Ra={4Δδ d 2 +Δδ p 2 +Δδ h 2} 1 / 2 A smaller Ra indicates higher compatibility, while a larger Ra indicates lower compatibility. Details of Hansen solubility parameters are described in *Hansen Solubility Parameters: A User's Handbook* by Charles M. Hansen (CRC Press, 2007), and for substances whose literature values etc. are unknown, calculation can be performed using the computer software Hansen Solubility Parameters in Practice (HSPiP).

[0031] As described above, by using, as the base polymer contained in the active energy ray-curable pressure-sensitive adhesive A, a base polymer having an HSP distance of 8 or more from the ultraviolet absorbing compound contained in the second pressure-sensitive adhesive layer, that is, by forming the first pressure-sensitive adhesive layer from a base polymer having low compatibility with the ultraviolet absorbing compound, migration of the ultraviolet absorbing compound into the first pressure-sensitive adhesive layer can be prevented. As a result, the ultraviolet absorbing compound is preferably unevenly distributed, and the effect of the present invention becomes remarkable.

[0032] The thickness of the first adhesive layer described above is preferably 1 μm to 60 μm, more preferably 2 μm to 30 μm, and even more preferably 3 μm to 20 μm.

[0033] The first adhesive layer described above has a viscosity of 460 mJ / cm². 2 It is preferable that the layer has an indentation modulus of 100 MPa or more at 23°C after irradiation with ultraviolet light, more preferably 200 MPa or more, and particularly preferably 300 MPa or more. If the first adhesive layer has such an indentation modulus after ultraviolet irradiation, strain will be generated in the adhesive layer by low-energy laser light irradiation, and as a result, the adherend (electronic component) can be peeled off smoothly. Furthermore, contamination of the electronic component during peeling can be prevented. 460 mJ / cm 2 The upper limit of the indentation modulus of the first adhesive layer after irradiation with ultraviolet light is, for example, 8000 MPa (preferably 5000 MPa, more preferably 4000 MPa). The indentation modulus can be measured by a single indentation method at 23°C with an indentation speed of 10 nm / s and an indentation depth of 100 nm.

[0034] B-2. Second adhesive layer (Activated energy ray curing adhesive) As described above, the second adhesive layer is composed of an active energy ray-curable adhesive B. In one embodiment, as the active energy ray-curable adhesive B, an active energy ray-curable adhesive (B1) is used, which comprises a base polymer that serves as the matrix and an active energy ray-reactive compound (monomer or oligomer) that can bond with the base polymer. In another embodiment, an active energy ray-curable adhesive (B2) is used, which comprises an active energy ray-reactive polymer as the base polymer. Preferably, the base polymer has a functional group that can react with a photopolymerization initiator. Examples of such functional groups include hydroxyl groups and carboxyl groups.

[0035] Examples of base polymers used in the above-mentioned adhesive (B1) include rubber-based polymers such as natural rubber, polyisobutylene rubber, styrene-butadiene rubber, styrene-isoprene-styrene block copolymer rubber, recycled rubber, butyl rubber, polyisobutylene rubber, and nitrile rubber (NBR); silicone-based polymers; and acrylic-based polymers. These polymers may be used individually or in combination of two or more. Among these, acrylic-based polymers are particularly preferred.

[0036] Examples of acrylic polymers include monopolymers or copolymers of hydrocarbon group-containing (meth)acrylic acid esters such as alkyl (meth)acrylates, cycloalkyl (meth)acrylates, and aryl (meth)acrylates; and copolymers of the hydrocarbon group-containing (meth)acrylic acid ester with other copolymerizable monomers. Examples of alkyl (meth)acrylates include methyl esters, ethyl esters, propyl esters, isopropyl esters, butyl esters, isobutyl esters, s-butyl esters, t-butyl esters, pentyl esters, isopentyl esters, hexyl esters, heptyl esters, octyl esters, 2-ethylhexyl esters, isooctyl esters, nonyl esters, decyl esters, isodecyl esters, undecyl esters, dodecyl esters, i.e., lauryl esters, tridecyl esters, tetradecyl esters, hexadecyl esters, octadecyl esters, and eicosyl esters. Examples of cycloalkyl (meth)acrylates include cyclopentyl esters and cyclohexyl esters of (meth)acrylic acid. Examples of (meth)acrylate aryl esters include phenyl (meth)acrylate and benzyl (meth)acrylate. The content of the constituent units derived from the hydrocarbon group-containing (meth)acrylate is preferably 40 parts by weight or more, and more preferably 60 parts by weight or more, per 100 parts by weight of the base polymer.

[0037] Other copolymerizable monomers include, for example, carboxyl group-containing monomers, acid anhydride monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphate group-containing monomers, acrylamide, and functional group-containing monomers such as acrylonitrile. Examples of carboxyl group-containing monomers include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of acid anhydride monomers include maleic anhydride and itaconic anhydride. Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. Examples of glycidyl group-containing monomers include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate. Examples of sulfonic acid group-containing monomers include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. An example of a phosphate group-containing monomer is 2-hydroxyethyl acryloyl phosphate. An example of an acrylamide is N-acryloylmorpholine. These may be used individually or in combination of two or more. The content of the constituent units derived from the above copolymerizable monomers is preferably 60 parts by weight or less, and more preferably 40 parts by weight or less, per 100 parts by weight of the base polymer.

[0038] Acrylic polymers may contain structural units derived from polyfunctional monomers to form crosslinked structures within their polymer backbone. Examples of polyfunctional monomers include hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy(meth)acrylate (i.e., polyglycidyl(meth)acrylate), polyester(meth)acrylate, and urethane(meth)acrylate. These may be used individually or in combination of two or more. The content of the structural units derived from the above polyfunctional monomers is preferably 40 parts by weight or less, and more preferably 30 parts by weight or less, per 100 parts by weight of the base polymer.

[0039] The weight-average molecular weight of the above acrylic polymer is preferably 100,000 to 3,000,000, and more preferably 200,000 to 2,000,000. The weight-average molecular weight can be measured by GPC (solvent: THF).

[0040] Examples of the active energy ray-reactive compounds that can be used in the above adhesive (B1) include photoreactive monomers or oligomers having a functional group with polymerizable carbon-carbon multiple bonds, such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, or an acetylene group. Specific examples of the photoreactive monomer include esters of (meth)acrylic acid with polyhydric alcohols such as trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate; polyfunctional urethane (meth)acrylate; epoxy (meth)acrylate; and oligoester (meth)acrylate. In addition, monomers such as methacryloisocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), and m-isopropenyl-α,α-dimethylbenzyl isocyanate may also be used. Specific examples of photoreactive oligomers include dimers to pentamers of the above-mentioned monomers. The molecular weight of the photoreactive oligomer is preferably 100 to 3000.

[0041] In one embodiment, a polyfunctional (meth)acrylate having five or more functional groups, or an oligomer of a polyfunctional (meth)acrylate having five or more functional groups, is used as the active energy ray reactive compound. By using such an active energy ray reactive compound, an adhesive layer that can become highly elastic upon irradiation with active energy rays (e.g., ultraviolet light) can be formed. If the adhesive layer can be made highly elastic, the above peeling operation can be performed using low-power laser light.

[0042] Furthermore, monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, and vinylsiloxane, or oligomers composed of such monomers, may be used as the active energy ray-reactive compound.

[0043] Furthermore, as the active energy ray-reactive compound, a mixture of organic salts such as onium salts and compounds having multiple heterocycles in their molecule may be used. In this mixture, irradiation with active energy rays (e.g., ultraviolet rays, electron beams) can cause the organic salts to cleave and generate ions, which act as initiating species to trigger ring-opening reactions of the heterocycles and form a three-dimensional network structure. Examples of the organic salts include iodonium salts, phosphonium salts, antimonium salts, sulfonium salts, and borate salts. Examples of heterocycles in the compounds having multiple heterocycles in their molecule include oxiranes, oxetanes, oxolanes, thirans, and aziridines.

[0044] In the above adhesive (B1), the content ratio of the active energy ray-reactive compound is preferably 0.1 to 500 parts by weight, more preferably 5 to 300 parts by weight, and even more preferably 40 to 150 parts by weight, per 100 parts by weight of the base polymer.

[0045] Examples of active energy ray-reactive polymers (base polymers) included in the above adhesive (B2) include polymers having functional groups with carbon-carbon multiple bonds, such as acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, and acetylene groups. Specific examples of active energy ray-reactive polymers include polymers composed of polyfunctional (meth)acrylates; photocationic polymers; cinnamoyl group-containing polymers such as polyvinyl cinnamate; diazotized amino novolac resins; polyacrylamide; and the like.

[0046] In one embodiment, an active energy ray reactive polymer is used, which is constructed by introducing an active energy ray polymerizable carbon-carbon double bond into the side chains, main chain, and / or main chain terminals of the above-mentioned acrylic polymer. As a method for introducing a radiation-polymerizable carbon-carbon double bond into an acrylic polymer, for example, an acrylic polymer is obtained by copolymerizing raw material monomers containing a monomer having a predetermined functional group (first functional group), and then a compound having a predetermined functional group (second functional group) that can react and bond with the first functional group and a radiation-polymerizable carbon-carbon double bond is subjected to a condensation or addition reaction with the acrylic polymer while maintaining the radiation polymerizability of the carbon-carbon double bond.

[0047] Examples of combinations of the first and second functional groups include carboxyl group and epoxy group, epoxy group and carboxyl group, carboxyl group and aziridyl group, aziridyl group and carboxyl group, hydroxyl group and isocyanate group, and isocyanate group and hydroxyl group. Of these combinations, from the viewpoint of ease of reaction tracking, the combination of hydroxyl group and isocyanate group, or the combination of isocyanate group and hydroxyl group is preferred. Furthermore, since it is technically difficult to produce polymers having highly reactive isocyanate groups, from the viewpoint of ease of production or availability of acrylic polymers, it is more preferable that the first functional group on the acrylic polymer side is a hydroxyl group and the second functional group is an isocyanate group. In this case, examples of isocyanate compounds having both a radiation-polymerizable carbon-carbon double bond and an isocyanate group as the second functional group include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate. Furthermore, as the acrylic polymer having the first functional group, it is preferable that it contains structural units derived from the above-mentioned hydroxyl group-containing monomer, and it is also preferable that it contains structural units derived from ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether.

[0048] The adhesive (B2) described above may further contain the active energy ray-reactive compound (monomer or oligomer) described above.

[0049] The above-mentioned active energy ray-curable adhesive B contains an ultraviolet absorbing compound. The ultraviolet absorbing compound is produced by adding an ultraviolet absorber to prepare active energy ray-curable adhesive B.

[0050] (UV absorber) Any suitable UV absorber can be used as the UV absorber, as long as it is a compound that absorbs ultraviolet light (e.g., wavelength 355 nm). Examples of UV absorbers include benzotriazole UV absorbers, benzophenone UV absorbers, triazine UV absorbers, salicylate UV absorbers, and cyanoacrylate UV absorbers. Among these, triazine UV absorbers or benzotriazole UV absorbers are preferred, and triazine UV absorbers are particularly preferred. Triazine UV absorbers are more preferably composed of compounds having hydroxyl groups, and are particularly preferably UV absorbers composed of hydroxyphenyltriazine compounds (hydroxyphenyltriazine UV absorbers).

[0051] Examples of hydroxyphenyltriazine-based UV absorbers include the reaction product of 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl)-5-hydroxyphenyl and [(C10-C16 (mainly C12-C13) alkyloxy)methyl]oxirane (trade name "TINUVIN 400", manufactured by BASF), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol), and the reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester (trade name "TINUVIN 400"). 405 (manufactured by BASF), 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (product name "TINUVIN 460", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol (product name "TINUVIN 1577", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (product name "ADEKA Stab LA-46", manufactured by ADEKA Corporation), 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (product name "TINUVIN Examples include "479" (manufactured by BASF) and "TINUVIN 477" (a product name by BASF).

[0052] Examples of benzotriazole-based UV absorbers (benzotriazole compounds) include 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (trade name "TINUVIN PS", manufactured by BASF), benzenepropanoic acid and ester compounds of 3-(2H-benzotriazole-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy(C7-9 side chain and linear alkyl) (trade name "TINUVIN 384-2", manufactured by BASF), octyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate and a mixture of 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate (trade name "TINUVIN Reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (product name "TINUVIN 900", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (product name "TINUVIN 928", manufactured by BASF), reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 (product name "TINUVIN 1130", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-p-cresol (product name "TINUVIN P (manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN 234", manufactured by BASF), 2-[5-chloro-2H-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (trade name "TINUVIN 326", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (trade name "TINUVIN 328", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-Tetramethylbutyl)phenol (trade name "TINUVIN 329", manufactured by BASF), 2,2'-Methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol] (trade name "TINUVIN 360", manufactured by BASF), reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate and polyethylene glycol 300 (trade name "TINUVIN 213", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (trade name "TINUVIN 571", manufactured by BASF), 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole (trade name "Sumisorb" 250", manufactured by Sumitomo Chemical Co., Ltd., 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole (product name "SEESORB 703", manufactured by Cipro Chemical Co., Ltd.), 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimidylmethyl)phenol (product name "SEESORB 706", manufactured by Cipro Chemical Co., Ltd.), 2-(4-benzoyloxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole (product name "SEESORB 7012BA", manufactured by Cipro Chemical Co., Ltd.), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (product name "SEESORB 706", manufactured by Cipro Chemical Co., Ltd.) Examples include 73 (manufactured by Chemipro Chemical Co., Ltd.), 2,2'-methylenebis[6-(2H-benzotriazole-2-yl)-4-tert-octylphenol] (product name "ADEKA Stab LA-31", manufactured by ADEKA Corporation), 2-(2H-benzotriazole-2-yl)-p-cellulose (product name "ADEKA Stab LA-32", manufactured by ADEKA Corporation), and 2-(5-chloro-2H-benzotriazole-2-yl)-6-tert-butyl-4-methylphenol (product name "ADEKA Stab LA-36", manufactured by ADEKA Corporation).

[0053] The above-mentioned ultraviolet absorber may be a dye or a pigment. Examples of pigments include azo, phthalocyanine, anthraquinone, lake, perylene, perinone, quinacridone, thioindigo, dioxandine, isoindolinone, and quinophthalone pigments. Examples of dyes include azo, phthalocyanine, anthraquinone, carbonyl, indigo, quinoneimine, methine, quinoline, and nitro dyes.

[0054] The molecular weight of the compounds constituting the above-mentioned ultraviolet absorber is preferably 1000 or less, more preferably 800 or less, and even more preferably 600 or less. The lower limit of the molecular weight of the compounds constituting the ultraviolet absorber is, for example, 100.

[0055] The maximum absorption wavelength of the above-mentioned ultraviolet absorber is preferably 300 nm to 450 nm, more preferably 320 nm to 400 nm, and even more preferably 330 nm to 380 nm.

[0056] In one embodiment, the UV absorber itself may be the UV absorbing compound in the second adhesive layer. In this case, the content of the UV absorbing compound is preferably 1 to 50 parts by weight, more preferably 2 to 30 parts by weight, and even more preferably 3 to 25 parts by weight, per 100 parts by weight of the base polymer in the second adhesive layer. Within this range, when the adhesive strength of the entire second adhesive layer is reduced by irradiation with active energy rays, the hardening of the adhesive layer proceeds well, and an adhesive sheet exhibiting good peelability can be obtained by laser light irradiation.

[0057] In another embodiment, the UV-absorbing compound in the second adhesive layer may be in a form in which the UV absorber is copolymerized to the base polymer. The UV-absorbing compound in this embodiment can be obtained, for example, by polymerizing the base polymer using a monomer composition containing a UV-absorbing monomer. That is, the active energy ray-curable adhesive B constituting the second adhesive layer may contain a base polymer having a UV-absorbing structure as the UV-absorbing compound. In this form, migration of the UV-absorbing compound to the first adhesive layer can be prevented. As a result, the UV-absorbing compound is preferably unevenly distributed, and the effects of the present invention become more pronounced.

[0058] As ultraviolet absorbers that can be bonded to the base polymer by copolymerization, for example, compounds (monomers) containing an ultraviolet absorbing group and a polymerizable group can be used. Examples of ultraviolet absorbing groups include benzotriazole skeletons, benzophenone skeletons, and triazine skeletons. In one embodiment, an acrylic monomer containing an ultraviolet absorbing group and a (meth)acryloyl group is used. Specific examples of such acrylic monomers include 3-(2H-benzotriazole-2-yl)-4-hydroxyphenethyl=methacrylate, 2-(4-benzoyl-3-hydroxyphenoxy)ethyl acrylate, and 2-[4-(4,6-diphenyl)-[1,3,5]triazine-2-yl]-3-hydroxyphenoxyethylprop-2-enoate. Commercially available products such as "RUVA-93" (manufactured by Otsuka Chemical Co., Ltd., trade name) can be suitably used.

[0059] In a form in which an ultraviolet absorber is copolymerized to a base polymer, the content ratio of constituent units derived from the ultraviolet absorber in the ultraviolet absorbing compound (base polymer) is preferably 1 to 50 parts by weight, more preferably 2 to 30 parts by weight, and even more preferably 3 to 25 parts by weight, per 100 parts by weight of the ultraviolet absorbing compound. Within this range, an adhesive sheet with an excellent balance between light transmission properties and peelability can be obtained.

[0060] (Crosslinking agent) Preferably, the active energy ray curing adhesive B contains a crosslinking agent. Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, amine-based crosslinking agents, and the like.

[0061] The content ratio of the above crosslinking agent is preferably 0.5 to 10 parts by weight, and more preferably 1 to 8 parts by weight, per 100 parts by weight of the base polymer of the adhesive.

[0062] In one embodiment, an isocyanate-based crosslinking agent is preferably used. Isocyanate-based crosslinking agents are preferred because they can react with a variety of functional groups. Specific examples of the above-mentioned isocyanate-based crosslinking agents include: lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate; isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate L"), trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HL"), and isocyanurate derivative of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HX"); and the like. Preferably, a crosslinking agent having three or more isocyanate groups is used.

[0063] In one embodiment, a crosslinking agent a having a functional group that can interact with the functional group of the UV-absorbing compound is used. Examples of such crosslinking agents a include those having an isocyanate group, a glycidyl group, or an amine group. Examples of combinations between the functional group of the UV-absorbing compound and the functional group of crosslinking agent a include an isocyanate group and a hydroxyl group, a glycidyl group and a hydroxyl group, or an amine group and a hydroxyl group.

[0064] (Photopolymerization initiator) In one embodiment, the active energy ray curable adhesive B includes a photopolymerization initiator. Any suitable initiator can be used as the photopolymerization initiator. Examples of photopolymerization initiators include α-ketol compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexylphenyl ketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; and ketal compounds such as benzyldimethyl ketal. Examples include aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxides; and acylphosphonates. The amount of photopolymerization initiator used can be set to any appropriate amount.

[0065] In one embodiment, a photopolymerization initiator having two or more (preferably two to five) photodegradable groups is used as the photopolymerization initiator. Using such a photopolymerization initiator, an adhesive layer that can become highly elastic upon irradiation with active energy rays (e.g., ultraviolet light) can be formed. If the second adhesive layer can be made highly elastic, the above peeling operation can be performed with low-power laser light. A photodegradable group refers to a functional group that absorbs irradiated active energy rays and generates radicals, and specific examples include ketone groups, alkyl halides, ester groups, sulfone groups, and peroxy groups.

[0066] Examples of photopolymerization initiators having two or more photodegradable groups include 2-hydroxy-1-4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl-2-methyl-propan-1-one (trade name Omnirad127, manufactured by BASF Japan), 1-[4-(4-benzoixylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one (trade name ESURE1001M), methylbenzoylformate (trade name SPEEDCURE MBF LAMBSON), O-ethoxyimino-1-phenylpropan-1-one (trade name SPEEDCURE PDO LAMBSON), and oligo[2-hydroxy-2-methyl-[4-(1-methylvinyl)phenyl]propanone] (trade name ESCURE KIPI50, manufactured by LAMBERTI).

[0067] In one embodiment, a compound containing a phosphorus atom and / or a nitrogen atom is used as the photopolymerization initiator. Examples of such photopolymerization initiators include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (trade name Omnirad907, manufactured by BASF Japan), 2-benzyl-2-(dimethylamino)-4'-morpholinbutyrophenone (trade name Omnirad369, manufactured by BASF Japan), 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)butan-1-one (trade name Omnirad379, manufactured by BASF Japan), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (trade name Omnirad819, manufactured by BASF Japan), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name OmniradTPO, manufactured by BASF Japan), and 1,2-octanedione-1-[4-(phenylthio)phenyl-2-(O-benzoyloxime)] (trade name Examples include OmniradOXE01 (manufactured by BASF Japan) and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyloxime) (trade name OmniradOXE02, manufactured by BASF Japan). Using such photopolymerization initiators, it is possible to form an adhesive layer that can become highly elastic by irradiation with active energy rays (e.g., ultraviolet light). If the second adhesive layer can be made highly elastic, the above peeling operation can be performed with low-power laser light.

[0068] The content ratio of the above-mentioned photopolymerization initiator is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and even more preferably 3 to 15 parts by weight, per 100 parts by weight of the base polymer in the second adhesive layer. Within this range, when the adhesive strength of the entire second adhesive layer is reduced by irradiation with active energy rays, the curing of the second adhesive layer proceeds well, and an adhesive sheet can be obtained in which the amount of strain of the second adhesive layer due to laser light irradiation is large and exhibits good peelability.

[0069] (Photosensitizer) In one embodiment, the active energy ray-curable adhesive B may include a photosensitizer.

[0070] In one embodiment, the photosensitizer may be used in combination with the photopolymerization initiator. The photosensitizer can generate radicals from the photopolymerization initiator by transferring the energy it obtains from absorbing light to the photopolymerization initiator, thereby enabling polymerization to proceed with long-wavelength light where the photopolymerization initiator itself does not have an absorption peak. For this reason, by including the photosensitizer, it is possible to increase the difference between the absorption wavelength of the ultraviolet absorption compound and the wavelength at which radicals can be generated from the photopolymerization initiator. As a result, the photopolymerization of the second adhesive layer and peeling by laser irradiation can be performed without mutual interference. In one embodiment, 2,2-dimethoxy-1,2-diphenylethane-1-one (e.g., BASF product name "Irgacure 651") as a photopolymerization initiator and the photosensitizer are used in combination. Examples of such photosensitizers include "UVS-581" manufactured by Kawasaki Chemical Industries, Ltd., and 9,10-diethoxyanthracene (for example, "UVS1101" manufactured by Kawasaki Chemical Industries, Ltd.).

[0071] Other examples of the above-mentioned photosensitizers include 9,10-dibutoxyanthracene (e.g., Kawasaki Chemical Industries, Ltd., trade name "UVS-1331"), 2-isopropylthioxanthone, benzophenone, thioxanthone derivatives, and 4,4'-bis(dimethylamino)benzophenone. Examples of thioxanthone derivatives include ethoxycarbonylthioxanthone and isopropylthioxanthone.

[0072] The content ratio of the above-mentioned photosensitizer is preferably 0.01 to 2 parts by weight, and more preferably 0.5 to 2 parts by weight, per 100 parts by weight of the base polymer.

[0073] Active energy ray curing adhesives may further contain any suitable additives as needed. Examples of additives include active energy ray polymerization accelerators, radical scavengers, tackifiers, plasticizers (e.g., trimellitic acid ester plasticizers, pyromellitic acid ester plasticizers, etc.), pigments, dyes, fillers, antioxidants, conductive materials, antistatic agents, light stabilizers, release modifiers, softeners, surfactants, flame retardants, antioxidants, and the like.

[0074] (Characteristics of the second adhesive layer) The thickness of the second adhesive layer described above is preferably 20 μm or less. Within this range, it is possible to lower the laser power during peeling, and an adhesive sheet with excellent peeling properties can be obtained. The thickness of the adhesive layer is more preferably 15 μm or less, even more preferably 10 μm or less, and most preferably 1 μm to 10 μm. Within this range, the above effects become more pronounced.

[0075] The second adhesive layer described above has an initial indentation modulus at 23°C that is preferably 4 MPa or less, more preferably 3 MPa or less, and even more preferably 2 MPa or less. Within this range, the second adhesive layer having such an indentation modulus allows a portion of the electronic component to be preferably embedded in the second adhesive layer when the electronic component is attached, enabling good temporary fixing of the electronic component. Furthermore, the initial indentation modulus of the second adhesive layer at 23°C is preferably 0.1 MPa or more, more preferably 0.2 MPa or more, even more preferably 0.3 MPa or more, and particularly preferably 0.7 MPa or more. Within this range, an adhesive sheet that is less likely to contaminate the adherend and has excellent peelability can be obtained. "Initial indentation modulus" refers to the indentation modulus before irradiation with active energy rays and laser light.

[0076] The second adhesive layer described above has a viscosity of 460 mJ / cm². 2It is preferable that the layer has an indentation modulus of 150 MPa or more at 23°C after irradiation with ultraviolet light, more preferably 200 MPa or more, and particularly preferably 250 MPa or more. If a second adhesive layer is provided that can have such an indentation modulus after irradiation with ultraviolet light, strain will be generated in the second adhesive layer by irradiation with low-energy laser light, and as a result, the adherend (electronic component) can be peeled off smoothly. Furthermore, contamination of the electronic component during peeling can be prevented. 460 mJ / cm 2 The upper limit of the indentation modulus of the second adhesive layer after irradiation with ultraviolet light is, for example, 8000 MPa (preferably 5000 MPa, more preferably 4000 MPa).

[0077] C. Base material The above-mentioned substrate may be composed of any suitable resin. Examples of such resins include polyethylene resins, polypropylene resins, polybutene resins, polymethylpentene resins and other polyolefin resins, polyurethane resins, polyester resins, polyimide resins, polyetherketone resins, polystyrene resins, polyvinyl chloride resins, polyvinylidene chloride resins, fluorine resins, silicone resins, cellulose resins, ionomer resins, and the like. Polyolefin resins are preferred among these.

[0078] The thickness of the above substrate is preferably 2 μm to 300 μm, more preferably 2 μm to 100 μm, and even more preferably 2 μm to 50 μm.

[0079] The light transmittance of the substrate at a wavelength of 355 nm is preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, and particularly preferably 95% or more. The upper limit of the total light transmittance of the substrate is, for example, 98% (preferably 99%).

[0080] D. Method for manufacturing adhesive sheets The above-mentioned adhesive sheet can be manufactured by any suitable method. The adhesive sheet can be obtained, for example, by coating the adhesive onto a substrate or a release liner. Various coating methods can be employed, such as bar coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, lip coating, die coating, dip coating, offset printing, flexographic printing, and screen printing. Alternatively, a method in which an adhesive layer is formed on a release liner and then bonded to the substrate may be employed.

[0081] E. Method for transporting electronic components In one embodiment, a method for transferring electronic components using the adhesive sheet described above is provided. This transfer method includes, for example, a first step of transferring a plurality of electronic components arranged on a substrate onto an adhesive laminate (second adhesive layer) of the adhesive sheet; and a second step of transferring the electronic components on the adhesive sheet to another member. Preferably, the same adhesive sheet is used in the first and second steps. That is, the transfer method may be performed without including any further transfer steps.

[0082] In the first step, the transfer of electronic components from the substrate to the adhesive sheet may be carried out by a process that includes irradiating the substrate / electronic component interface with laser light, i.e., a laser lift-off process. The conditions of the laser lift-off process can be any suitable conditions.

[0083] As the substrate mentioned above, a hard substrate such as a sapphire substrate may be used.

[0084] In one embodiment, the second step includes the following operations: (i) irradiating the adhesive sheet with active energy rays (e.g., ultraviolet light) to reduce the adhesive strength of the adhesive laminate of the adhesive sheet; and (ii) irradiating the area where peelability is desired with laser light to cause strain in the second adhesive layer and further reduce the adhesive strength. According to this method, electronic components can be peeled off only at the area irradiated with laser light. By using the adhesive sheet of the present invention, the adhesive strength can be reduced to the point where it will fall off naturally, making it possible to peel off even very small electronic components (e.g., 50 μm square) individually.

[0085] The active energy rays in (i) above can be irradiated over the entire surface of the adhesive laminate. In one embodiment, the integrated light intensity is 200 mJ / cm². 2 ~600 mJ / cm 2 Ultraviolet light is emitted.

[0086] The laser light used in (ii) above is, for example, laser light with a wavelength of 200 nm to 360 nm (preferably 355 nm). The laser light output is, for example, 100 mJ / cm². 2 ~1200 mJ / cm² 2 That is the case.

[0087] In one embodiment, the electronic component is a mini-LED or micro-LED. [Examples]

[0088] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The test and evaluation methods in the examples are as follows. Unless otherwise specified, "parts" and "%" are based on weight.

[0089] (1) Amount of UV-absorbing structure In each example and comparative example, a calibration curve for the UV absorption structure was obtained using FT-IR (ATR method) with a separate group of adhesive layer samples formed in the same manner except for the amount of UV absorber added. Specifically, FT-IR measurements were performed on several separate adhesive layer samples with different amounts of UV absorber added. Based on the ratio of the peak intensity at the absorption wavenumber derived from the base polymer (acrylic polymer) constituting the separate adhesive layer sample to the peak intensity at the absorption wavenumber derived from the UV absorption structure (UV absorber), a calibration curve of (amount of UV absorption structure) versus (peak intensity of UV absorption structure) was obtained. Subsequently, FT-IR (ATR method) measurements were performed on the adhesive layers formed in each example and comparative example to obtain peak intensities at absorption wavenumbers derived from the ultraviolet absorption structure, and the amount of ultraviolet absorption structure in the adhesive layer was identified from the calibration curve. From the amount of ultraviolet absorption structure in the adhesive layer, the ratio of ultraviolet absorption structures (amount of ultraviolet absorption structure on the outer surface of the first adhesive layer / amount of ultraviolet absorption structure on the outer surface of the second adhesive layer) was determined. The peak intensity of the absorption wavenumber derived from the UV absorption structure (UV absorber) was defined as the peak intensity at the following absorption wavenumbers. Example 1: 1594cm -1 Example 2: 1379 cm -1 Example 3, Comparative Example 2: 1509 cm -1 Examples 4-13, Comparative Example 3, 4:752cm -1 Furthermore, the peak intensity of the acrylic polymer was 1725 cm⁻¹. -1 ~1730cm -1 This was defined as the peak intensity at that point. For FT-IR (ATR method) measurements, the adhesive layer within a depth of 1 μm from the outer surface (the surface opposite to the interface between the first and second adhesive layers) was used as the measurement sample.

[0090] (2) Light transmittance at wavelength 355nm The PET release liner on one side of the adhesive sheet was peeled off, and the sheet was attached to a large microscope slide (manufactured by Matsunami Glass, product name "S9111") using a hand roller. The PET release liner on the other side was then peeled off, and measurements were taken. Specifically, a spectrophotometer (product name "Spectrophotometer U-4100", manufactured by Hitachi High-Tech Science) was used to measure the transmittance of the adhesive sheet at a wavelength of 355 nm on the large microscope slide.

[0091] (3-1) Indentation modulus (first adhesive layer / before UV irradiation) The PET release liner on the second adhesive layer side of the adhesive sheet was peeled off, and the second adhesive layer was bonded to a large microscope slide (manufactured by Matsunami Glass, product name "S9111") using a hand roller. Next, the PET release liner on the first adhesive layer side was peeled off, exposing the first adhesive layer, and the indentation modulus was measured using a Hysitron TI-950 tripindenter. The measurement was performed at 23°C using a single indentation method, with an indentation speed of 10 nm / s and an indentation depth of 100 nm. (3-2) Indentation modulus (first adhesive layer / after UV irradiation) The PET release liner on the second adhesive layer side of the adhesive sheet was peeled off, and the second adhesive layer was attached to a large microscope slide (manufactured by Matsunami Glass, product name "S9111") using a hand roller. An ultraviolet irradiation device (manufactured by Nitto Seiki, product name "UM-810") was used from the first adhesive layer side to emit ultraviolet light from a high-pressure mercury lamp (specific wavelength: 365 nm, integrated light intensity: 460 mJ / cm²). 2 The entire surface was irradiated with ). Then, the PET release liner on the first adhesive layer side was peeled off to expose the first adhesive layer, and the indentation modulus was measured using a Hysitron TI-950 tripindenter under the same conditions as in (3-1) above. (3-3) Indentation modulus (second adhesive layer / before UV irradiation) The PET release liner on the first adhesive layer side of the adhesive sheet was peeled off, and the first adhesive layer was attached to a large microscope slide (manufactured by Matsunami Glass, product name "S9111") using a hand roller. Next, the PET release liner on the second adhesive layer side was peeled off, exposing the second adhesive layer, and the indentation modulus was measured using a Hysitron TI-950 tripindenter under the same conditions as in (3-1) above. (3-4) Indentation modulus (second adhesive layer / after UV irradiation) The PET release liner on the first adhesive layer side of the adhesive sheet was peeled off, and the first adhesive layer was attached to a large microscope slide (manufactured by Matsunami Glass, product name "S9111") using a hand roller. An ultraviolet irradiation device (manufactured by Nitto Seiki, product name "UM-810") was used from the second adhesive layer side to emit ultraviolet light from a high-pressure mercury lamp (specific wavelength: 365 nm, integrated light intensity: 460 mJ / cm²). 2 The entire surface was irradiated with ). Subsequently, the PET release liner on the second adhesive layer side was peeled off to expose the second adhesive layer, and the indentation modulus was measured using a Hysitron TI-950 tripindenter under the same conditions as in (3-1) above.

[0092] (4) Laser Lift-Off (LLO) Evaluation After bonding the first adhesive layer onto a 4-inch square quartz glass, a sapphire substrate was bonded so that the LED chip was positioned on the second adhesive layer. The bonding was performed using a protective tape application device with a vacuum and press mechanism (product name "DV 3000", manufactured by Nitto Seiki Co., Ltd.), with a vacuum time of 90 seconds, a pressure setting of 0.25 MPa, and a pressure setting time of 0 seconds. After crimping was complete, a laser (excimer laser manufactured by M-Raise) was irradiated from the sapphire surface to perform LLO (Laser Laser Occlusion). The LLO conditions were: wavelength: 248 nm, energy density: 900 mJ / cm². 3 The following steps were taken. After LLO, the sapphire glass was removed and the yield was checked. Yield: 90% or higher was rated as good (〇), 80% to less than 90% was rated as acceptable (△), and less than 80% was rated as unacceptable (×).

[0093] (5) Laser Transfer Evaluation After LLO (Low-Layer Oxide), the adhesive layer of the obtained sample was photocured from the quartz glass side using an ultraviolet irradiation device (product name "UM 810", manufactured by Nitto Seiki Co., Ltd.) under a nitrogen atmosphere. The curing conditions were 460 mJ / cm using ultraviolet light from a high-pressure mercury lamp, with a wavelength of 365 nm. 2 That's what I decided. Subsequently, a laser (wavelength: 355 nm, pulse width: 5 ns) was irradiated only to the target chip location from the quartz glass side to perform laser transfer. The irradiation energy was 400 mJ / cm². 2 600 mJ / cm² 2 800 mJ / cm² 2 Three different laser beam conditions were applied to the chips, and those that transferred were marked with ○, while those that did not transfer were marked with ×. After transfer, the chips and adhesive sheets were observed using a digital microscope (product name "VHX2000", manufactured by Keyence Corporation). If debris was found around the chip or the adhesive sheet was decomposed, it was marked with Debris ×, and if no debris was found, it was marked with Debris ○.

[0094] [Manufacturing Example 1] Preparation of Acrylic Polymer A A monomer composition was prepared by mixing 100 parts by weight of 2-methoxyethyl acrylate, 27 parts by weight of acryloylmorpholine, and 22 parts by weight of 2-hydroxyethyl acrylate. Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, thermometer, and stirrer. Under a nitrogen atmosphere, 500 parts by weight of toluene, 149 parts by weight of the above monomer composition, and 0.3 parts by weight of benzoyl peroxide (BPO) were charged and stirred at 60°C for 5 hours. After that, the mixture was cooled to room temperature, and 24 parts by weight of 2-methacryloyloxyethyl isocyanate was added and reacted to add NCO groups to the OH groups at the end of the side chains of 2-hydroxyethyl acrylate in the copolymer, obtaining an acrylic polymer solution A containing acrylic polymer A having a carbon-carbon double bond at the end.

[0095] [Manufacturing Example 2] Preparation of Acrylic Polymer B A monomer composition was prepared by mixing 100 parts by weight of isononyl acrylate and 32 parts by weight of 2-hydroxyethyl acrylate. Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, thermometer, and stirrer. Under a nitrogen atmosphere, 280 parts by weight of ethyl acetate, 132 parts by weight of the above monomer composition, and 0.3 parts by weight of benzoyl peroxide (BPO) were charged and stirred at 60°C for 4 hours. After that, the mixture was cooled to room temperature, and 56 parts by weight of 2-methacryloyloxyethyl isocyanate was added and reacted to add NCO groups to the OH groups at the end of the side chains of 2-hydroxyethyl acrylate in the copolymer, obtaining an acrylic polymer solution B containing acrylic polymer B having a carbon-carbon double bond at the end.

[0096] [Manufacturing Example 3] Preparation of Acrylic Polymer C A monomer composition was prepared by mixing 100 parts by weight of 2-ethylhexyl acrylate, 25.5 parts by weight of acryloyl morpholine, and 18.5 parts by weight of 2-hydroxyethyl acrylate. Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, thermometer, and stirrer. Under a nitrogen atmosphere, 60 parts by weight of toluene, 144 parts by weight of the above monomer composition, and 0.3 parts by weight of benzoyl peroxide (BPO) were charged and stirred at 60°C for 4 hours. After that, the mixture was cooled to room temperature, and 22.5 parts by weight of 2-methacryloyloxyethyl isocyanate was added and reacted to add NCO groups to the terminal OH groups of the side chains of 2-hydroxyethyl acrylate in the copolymer, obtaining an acrylic polymer solution C containing an acrylic polymer C having a carbon-carbon double bond at its terminal.

[0097] [Manufacturing Example 4] Preparation of Acrylic Polymer D A monomer composition was prepared by mixing 70 parts by weight of ethyl acrylate, 30 parts by weight of 2-hydroxyethyl acrylate, and 5 parts by weight of methyl methacrylate. Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer. Under a nitrogen atmosphere, 295 parts by weight of ethyl acetate, 109 parts by weight of the above monomer composition, and 0.2 parts by weight of benzoyl peroxide (BPO) were charged and stirred at 60°C for 4 hours to obtain an acrylic polymer solution D containing acrylic polymer D.

[0098] [Manufacturing Example 5] Preparation of Acrylic Polymer E A monomer composition was prepared by mixing 106 parts by weight of 2-methoxyethyl acrylate, 22 parts by weight of acryloylmorpholine, 24 parts by weight of 2-hydroxyethyl acrylate, and 16.5 parts by weight of an ultraviolet absorber (manufactured by Otsuka Chemical Co., Ltd., trade name "RUVA-93"). Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, thermometer, and stirrer. Under a nitrogen atmosphere, 430 parts by weight of ethyl acetate, 168.5 parts by weight of the monomer composition, and 0.35 parts by weight of AIBN were charged and stirred at 63°C for 5 hours. After that, the mixture was cooled to room temperature, and 28 parts by weight of 2-methacryloyloxyethyl isocyanate was added and reacted to obtain an acrylic polymer solution E containing an acrylic polymer E having a carbon-carbon double bond at its terminal and an ultraviolet absorbing structure, by adding NCO groups to the terminal OH groups of the side chains of 2-hydroxyethyl acrylate in the copolymer.

[0099] [Manufacturing Example 6] Preparation of Acrylic Polymer F A monomer composition was prepared by mixing 106 parts by weight of 2-methoxyethyl acrylate, 27 parts by weight of acryloylmorpholine, 40 parts by weight of 2-hydroxyethyl acrylate, and 18.5 parts by weight of an ultraviolet absorber (manufactured by Otsuka Chemical Co., Ltd., trade name "RUVA-93"). Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, thermometer, and stirrer. Under a nitrogen atmosphere, 400 parts by weight of ethyl acetate, 191.5 parts by weight of the monomer composition, and 0.4 parts by weight of AIBN were charged and stirred at 63°C for 5 hours. After that, the mixture was cooled to room temperature, and 43 parts by weight of 2-methacryloyloxyethyl isocyanate was added and reacted to obtain an acrylic polymer solution F containing an acrylic polymer F having a carbon-carbon double bond at its terminal and to which an ultraviolet absorber was bonded.

[0100] [Manufacturing Example 7] Preparation of Acrylic Polymer G A monomer composition was prepared by mixing 65 parts by weight of isononyl acrylate, 25 parts by weight of 2-hydroxyethyl acrylate, and 5 parts by weight of an ultraviolet absorber (manufactured by Otsuka Chemical Co., Ltd., trade name "RUVA-93"). Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, thermometer, and stirrer. Under a nitrogen atmosphere, 200 parts by weight of ethyl acetate, 95 parts by weight of the monomer composition, and 0.2 parts by weight of AIBN were charged and stirred at 63°C for 5 hours. After that, the mixture was cooled to room temperature, and 31 parts by weight of 2-methacryloyloxyethyl isocyanate was added and reacted to obtain an acrylic polymer solution G containing an acrylic polymer G having a carbon-carbon double bond at its terminal and to which an ultraviolet absorber was bonded.

[0101] [Manufacturing Example 8] Preparation of Acrylic Polymer H A monomer composition was prepared by mixing 113 parts by weight of isononyl acrylate, 44 parts by weight of 2-hydroxyethyl acrylate, and 17.5 parts by weight of an ultraviolet absorber (manufactured by Otsuka Chemical Co., Ltd., trade name "RUVA-93"). Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, thermometer, and stirrer. Under a nitrogen atmosphere, 320 parts by weight of ethyl acetate, 174.5 parts by weight of the monomer composition, and 0.35 parts by weight of AIBN were charged and stirred at 63°C for 5 hours. After that, the mixture was cooled to room temperature, and 60 parts by weight of 2-methacryloyloxyethyl isocyanate was added and reacted to obtain an acrylic polymer solution H containing an acrylic polymer H having a carbon-carbon double bond at its terminal and to which an ultraviolet absorber was bonded, by adding an NCO group to the OH group at the end of the side chain of 2-hydroxyethyl acrylate in the copolymer.

[0102] [Example 1] (Preparation of adhesive (1a)) To an acrylic polymer solution A containing 100 parts by weight of acrylic polymer A (solids), 3 parts by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A") and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain an adhesive (1a). (Preparation of adhesive (2a)) To an acrylic polymer solution B containing 100 parts by weight of acrylic polymer B (solids), 1 part by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A"), 10 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 928", 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol), and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain an adhesive (2a). (Adhesive sheet) The above adhesive (1a) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a first adhesive layer with a thickness of 4 μm. Separately, the above adhesive (2a) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a second adhesive layer with a thickness of 1 μm. The first adhesive layer and the second adhesive layer were bonded together to obtain an adhesive sheet with a release liner (release liner / first adhesive layer / second adhesive layer / release liner). The obtained adhesive sheets with release liners were subjected to the above evaluation. The results are shown in Table 1.

[0103] [Example 2] A release liner-attached adhesive sheet was obtained in the same manner as in Example 1, except that 10 parts by weight of an ultraviolet absorber (BASF, product name "Tinuvin 477") was used instead of 10 parts by weight of an ultraviolet absorber (BASF, product name "Tinuvin 928"). The obtained release liner-attached adhesive sheet was subjected to the above evaluation. The results are shown in Table 1.

[0104] [Example 3] (Preparation of adhesive (1b)) To an acrylic polymer solution B containing 100 parts by weight of acrylic polymer B (solids), 1 part by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A") and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain an adhesive (1b). (Preparation of adhesive (2b)) To an acrylic polymer solution B containing 100 parts by weight of acrylic polymer B (solids), 3 parts by weight (solids) of a crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate / HX"), 10 parts by weight of a UV absorber (manufactured by BASF, trade name "Tinuvin 405", reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester), and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain adhesive (2b). The crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate / HX") is a crosslinking agent that can react with the OH group of the UV absorber. (Adhesive sheet) The above adhesive (1b) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a first adhesive layer with a thickness of 4 μm. Separately, the above adhesive (2b) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a second adhesive layer with a thickness of 1 μm. The first adhesive layer and the second adhesive layer were bonded together to obtain an adhesive sheet with a release liner (release liner / first adhesive layer / second adhesive layer / release liner). The obtained adhesive sheets with release liners were subjected to the above evaluation. The results are shown in Table 1.

[0105] [Example 4] (Preparation of adhesive (1c)) To an acrylic polymer solution A containing 100 parts by weight of acrylic polymer A (solids), 3 parts by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A") and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain an adhesive (1c). (Preparation of adhesive (2c)) To an acrylic polymer solution E containing 100 parts by weight of acrylic polymer E (solids), 1 part by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A") and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain an adhesive (2c). (Adhesive sheet) The above adhesive (1c) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a first adhesive layer with a thickness of 8 μm. Separately, the above adhesive (2b) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a second adhesive layer with a thickness of 2 μm. The first adhesive layer and the second adhesive layer were bonded together to obtain an adhesive sheet with a release liner (release liner / first adhesive layer / second adhesive layer / release liner). The obtained adhesive sheets with release liners were subjected to the above evaluation. The results are shown in Table 1.

[0106] [Examples 5-13] An adhesive sheet was obtained in the same manner as in Example 4, except that the acrylic polymer solution, crosslinking agent, and photopolymerization initiator shown in Table 1 were used in the amounts (solid content) shown in Table 1. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 1. The compounds used in the examples and comparative examples are as follows: (Crosslinking agent) • D-101A: Isocyanate-based crosslinking agent, manufactured by Mitsui Chemicals, Inc., product name "Takenate D-101A" • Coronate HX: Isocyanate-based crosslinking agent, manufactured by Tosoh Corporation, product name "Coronate / HX" (Photopolymerization initiator) ·Omni127D: Manufactured by BASF, product name "Omnirad127D", compound name: 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one • OmniTPO: Manufactured by BASF, trade name "OmniradTPO", compound name: 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide

[0107] [Comparative Example 1] (Preparation of adhesive (1a)) Adhesive (1a) was obtained in the same manner as in Example 1. (Adhesive sheet) The above adhesive (1a) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a first adhesive layer with a thickness of 10 μm. A release liner was bonded to the first adhesive layer described above to obtain an adhesive sheet with a release liner (release liner / first adhesive layer / release liner). The obtained adhesive sheets with release liners were subjected to the above evaluation. The results are shown in Table 1.

[0108] [Comparative Example 2] (Preparation of adhesive (2c)) To an acrylic polymer solution A containing 100 parts by weight of acrylic polymer A (solids), 3 parts by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A"), 5 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 405"), and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain an adhesive (2c). (Adhesive sheet) The above adhesive (1c) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a second adhesive layer with a thickness of 10 μm. A release liner was bonded to the second adhesive layer to obtain an adhesive sheet with a release liner (release liner / second adhesive layer / release liner). The obtained adhesive sheets with release liners were subjected to the above evaluation. The results are shown in Table 1.

[0109] [Comparative Example 3] (Preparation of adhesive (1d)) To an acrylic polymer solution D containing 100 parts by weight of acrylic polymer D (solids), 4 parts by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A") was added to obtain an adhesive (1d). (Preparation of adhesive (2d)) To an acrylic polymer solution H containing 100 parts by weight of acrylic polymer H (solids), 1 part by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A") and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain an adhesive (2d). (Adhesive sheet) The above adhesive (1d) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form an adhesive layer a with a thickness of 8 μm. Separately, the above adhesive (2d) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a second adhesive layer with a thickness of 2 μm. The above adhesive layer a and the second adhesive layer were bonded together to obtain an adhesive sheet with a release liner (release liner / adhesive layer a / second adhesive layer / release liner). The obtained adhesive sheets with release liners were subjected to the above evaluation. The results are shown in Table 1.

[0110] [Comparative Example 4] (Preparation of adhesive (1e)) To an acrylic polymer solution G containing 100 parts by weight of acrylic polymer G (solids), 1 part by weight (solids) of a crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D-101A") and 7 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad 127D") were added to obtain an adhesive (1e). (Preparation of adhesive (2d)) Adhesive (2d) was obtained in the same manner as in Comparative Example 3. (Adhesive sheet) The above adhesive (1e) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a first adhesive layer with a thickness of 8 μm. Separately, the above adhesive (2d) was applied to the silicone-treated surface of a PET release liner (thickness: 38 μm), and then heated at 130°C for 2 minutes to form a second adhesive layer with a thickness of 2 μm. The first adhesive layer and the second adhesive layer were bonded together to obtain an adhesive sheet with a release liner (release liner / first adhesive layer / second adhesive layer / release liner). The obtained adhesive sheets with release liners were subjected to the above evaluation. The results are shown in Table 1.

[0111] [Table 1]

[0112] As is clear from Table 1, the present invention provides an adhesive sheet with excellent ability to accept electronic components by a laser lift-off process. Furthermore, the adhesive sheet of the present invention exhibits desirable peelability when irradiated with appropriately set laser light. On the other hand, adhesive sheets with a single layer structure that do not contain an ultraviolet absorbing compound (Comparative Example 1), adhesive sheets with a single layer structure (Comparative Example 2), adhesive sheets with an adhesive layer that does not contain an active energy ray curing type adhesive (Comparative Example 3), and adhesive sheets with (amount of ultraviolet absorbing structure on the outer surface of the first adhesive layer / amount of ultraviolet absorbing structure on the outer surface of the second adhesive layer) greater than 0.3 (Comparative Example 4) exhibit poor peelability when irradiated with laser light. [Explanation of symbols]

[0113] 10 Adhesive laminate 11. First adhesive layer 12. Second adhesive layer 20 Base material 100, 200 adhesive sheets

Claims

1. The adhesive laminate comprises a first adhesive layer and a second adhesive layer disposed on one side of the first adhesive layer. The first adhesive layer and the second adhesive layer are directly arranged, The first adhesive layer is composed of an active energy ray curing type adhesive A. The second adhesive layer is composed of an active energy ray curable adhesive B. The adhesive laminate contains an ultraviolet absorbing compound having an ultraviolet absorbing structure, The active energy ray curing adhesive B contains a base polymer having an ultraviolet absorption structure, The amount of ultraviolet absorbing structure on the outer surface of the second adhesive layer and the amount of ultraviolet absorbing structure on the outer surface of the first adhesive layer satisfy the relationship shown in formula (1) below. Adhesive sheet for a laser lift-off process, on which an object is placed on the second adhesive layer; Amount of UV-absorbing structure on the outer surface of the first adhesive layer / Amount of UV-absorbing structure on the outer surface of the second adhesive layer ≤ 0.3 ... (1).

2. The adhesive sheet according to claim 1, wherein the light transmittance at a wavelength of 355 nm is 50% or less.

3. The adhesive sheet according to claim 1 or 2, wherein the HSP distance between the base polymer contained in the active energy ray curable adhesive A and the ultraviolet absorbing compound contained in the second adhesive layer is 8 or more.

4. The adhesive sheet according to claim 1 or 2, wherein the active energy ray curable adhesive B comprises a crosslinking agent a having a functional group that can interact with the functional group of the ultraviolet absorbing compound.

5. The adhesive sheet according to claim 1 or 2, wherein the initial indentation modulus of the second adhesive layer at 23°C is 4 MPa or less.

6. The second adhesive layer has a viscosity of 460 mJ / cm². ２ The adhesive sheet according to claim 1 or 2, wherein the layer has an indentation modulus of 150 MPa or more at 23°C after irradiation with ultraviolet light.

7. The first adhesive layer has a viscosity of 460 mJ / cm². ２ The adhesive sheet according to claim 1 or 2, wherein the layer has an indentation modulus of 100 MPa or more at 23°C after irradiation with ultraviolet light.

8. The adhesive sheet according to claim 1 or 2, wherein the thickness is 60 μm or less.

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