TWI891901B - Adhesive sheet - Google Patents

Abstract

The present invention provides an adhesive sheet that can temporarily fix an adherend in a releasable manner. The releasability can be demonstrated by low-output laser light, eliminating the need for cleaning the adherend after peeling. Furthermore, the peeling demonstration area is narrow. The adhesive sheet of the present invention comprises an adhesive layer and a transfer layer disposed on one side of the adhesive layer. The transfer layer is hardened by irradiation with active energy rays. The adhesive layer of the adhesive sheet exhibits an adhesion force (I) of 2 N/20 mm or greater at 23°C when bonded to glass. The adhesive layer exhibits an adhesion force (I) of 2 N/20 mm or greater at 23°C when bonded to glass, and a ratio of the adhesion force (B) of the transfer layer at 23°C after irradiation with 300 mJ/ ^cm² of ultraviolet rays is 5 or greater.

Description

Adhesive sheet

The present invention relates to an adhesive sheet.

When processing various components, such as electronic parts, the following process is typically performed: the component is temporarily fixed to a support using an adhesive sheet. After transport and processing, the processed component is peeled from the support. For example, Patent Document 1 describes a method in which a substrate (the component to be processed) is temporarily fixed to a support with an adhesive layer and a separation layer interposed therebetween. After processing, the separation layer is destroyed by laser irradiation, and the substrate is peeled from the support along with the adhesive layer. The adhesive layer is then removed from the substrate. However, this method requires the steps of removing the adhesive layer from the component and cleaning the non-adhesive surface of the component, which poses a problem in terms of production costs. Furthermore, there is also the problem of damaging components when irradiating with high-output laser light.

Patent Document 2 describes a method in which multiple workpieces are temporarily fixed to a carrier through an adhesive layer. A laser beam is then focused on the adhesive layer to cause foaming, thereby selectively separating and transferring a portion of the workpieces from the carrier. However, this method suffers from the problem that the foaming generated by laser irradiation spreads over time, causing the carrier to peel off and the workpieces that do not need to be transferred to fall off unnecessarily. Prior Art Patent Document

Patent Document 1: Japanese Patent No. 5875850 Patent Document 2: Japanese Patent No. 6053756

[Identify the problem you want to solve]

The present invention was developed to resolve the aforementioned problems. Its purpose is to provide an adhesive sheet that can temporarily secure an adherend in a removable manner. The adhesive sheet can be releasably activated using low-output laser light, eliminating the need for post-stripping cleaning of the adherend. Furthermore, the area where the releasable adhesive sheet is activated is narrow. [Technical Solution]

The adhesive sheet of the present invention comprises an adhesive layer and a transfer layer disposed on one side of the adhesive layer. The transfer layer is hardened by exposure to active energy rays. When the adhesive layer of the adhesive sheet is bonded to a glass plate, the adhesive force (I) at 23°C is at least 2 N/20 mm. Furthermore, the ratio of the adhesive force (I) at 23°C to the adhesive force (B) at 23°C after irradiation of the transfer layer with 300 mJ/ ^cm² of ultraviolet light is 5 or greater. In one embodiment, the adhesive sheet further comprises a substrate between the adhesive layer and the transfer layer. In one embodiment, after irradiation with 300 mJ/ ^cm² of ultraviolet light, the transfer layer has an indentation modulus (B) at 23°C that is at least five times the indentation modulus (I) of the adhesive layer at 23°C. In one embodiment, the transfer layer contains an active energy ray-curable adhesive containing an acrylic polymer as a base polymer. In one embodiment, the adhesive sheet can be used to temporarily secure a component to a support, and then, after transport and/or processing, the component can be removed from the support by laser irradiation. [Effects of the Invention]

According to the present invention, an adhesive sheet can be provided that can temporarily fix an adherend in a releasable manner, and the releasability can be exhibited by low-output laser light, eliminating the need for cleaning the adherend after peeling, and the range of the peeling display area is narrow.

A. Adhesive Sheet Overview Figure 1(a) is a schematic cross-sectional view of an adhesive sheet according to one embodiment of the present invention. Adhesive sheet 100 of this embodiment comprises an adhesive layer 10 and a transfer layer 20 disposed on one side of adhesive layer 10. Figure 1(b) is a schematic cross-sectional view of an adhesive sheet according to another embodiment of the present invention. Adhesive sheet 200 of this embodiment further comprises a substrate 30 between adhesive layer 10 and transfer layer 20. Although not shown, the adhesive sheet of the present invention may also be provided with a peel liner outside the adhesive layer and transfer layer to protect the adhesive surface prior to use. Furthermore, as long as the effects of the present invention can be achieved, the adhesive sheet may further contain any other appropriate layers.

The adhesive sheet of the present invention can be used to temporarily fix a component to a support (e.g., a glass substrate) and then remove the component from the support after transportation or processing. During the removal process, laser light irradiation can precisely remove only the component at the desired location.

The transfer layer is a layer that hardens by irradiation with active energy rays. More specifically, the transfer layer is constructed in the following manner: it has an adhesive property for fixing an adherend, and hardens by irradiation with active energy rays, and the adhesive property is reduced. Preferably, after hardening, an adhesive force that can fix the adherend remains (for example, an adhesive force that prevents the adherend from falling off naturally). In one embodiment, the adhesive force of the entire transfer layer is reduced by irradiation with active energy rays. Examples of active energy rays include gamma rays, ultraviolet rays, visible rays, infrared rays (heat rays), radio frequency waves, alpha rays, beta rays, electron beams, plasma currents, ionizing radiation, and particle beams. Ultraviolet rays are preferred.

The adhesive layer can be of any appropriate structure as long as the effects of the present invention can be achieved. In one embodiment, the adhesive layer contains a pressure-sensitive adhesive. The adhesive sheet can be used by bonding the adhesive layer to a support (e.g., a glass substrate). The adhesive sheet can be peeled off by the following operation: the adhesive layer (including the substrate in a structure with a substrate) is locally strained by irradiating it with laser light, and the strain is transmitted to the transfer layer, causing the transfer layer surface (bonding surface) to temporarily change shape. In the present invention, by adjusting the adhesive layer's composition (e.g., the type of base polymer; the type and amount of additives such as adhesion promoters and crosslinkers), the adhesive layer can be made to absorb laser light of a specified wavelength, resulting in easier strain generation within the adhesive layer. Furthermore, by appropriately selecting the substrate's constituent materials, a strain-prone substrate can be created. Furthermore, as described above, by curing the transfer layer and then irradiating it with laser light, the releasability resulting from strain propagation can be optimally exhibited. In the present invention, the aforementioned action achieves releasability, eliminating the need for high-output laser light and the need for post-stripping washes. Furthermore, the area where the peeling occurs is narrowed. Furthermore, the surface shape of the transfer layer after peeling does not change continuously (i.e., the area does not widen over time and instead returns to its pre-change shape). This prevents unwanted shedding of the adherend in areas not requiring peeling.

When the adhesive layer of the adhesive sheet is attached to a glass plate, its adhesion strength (I) at 23°C is 2 N/20 mm or greater. By increasing this adhesion strength (I), deformation of the layers caused by laser irradiation can be optimized, narrowing the area where peeling occurs, and preventing abnormalities such as unwanted detachment of the adherend in areas where peeling is not necessary. The adhesion strength (I) is preferably 2 N/20 mm to 25 N/20 mm, and more preferably 5 N/20 mm to 20 N/20 mm. Within this range, the effects of the present invention are significantly achieved. Adhesion strength is measured in accordance with JIS Z 0237:2000. Specifically, the adhesive layer of the adhesive sheet is bonded to a glass plate (arithmetic mean surface roughness Ra: 50 ± 25 nm) by reciprocating a 2 kg roller once. After standing at 23°C for 30 minutes, the adhesive sheet is peeled off at a peeling angle of 180° and a peeling speed (tensile speed) of 300 mm/min for measurement.

The initial adhesion force A of the transfer layer of the adhesive sheet at 23°C, immediately after being bonded to the stainless steel plate, is preferably 1 N/20 mm to 20 N/20 mm, more preferably 1.5 N/20 mm to 15 N/20 mm, and even more preferably 2 N/20 mm to 10 N/20 mm. Within this range, an adhesive sheet capable of effectively retaining the adherend is obtained. The adhesion force of the transfer layer is also measured in accordance with JIS Z 0237:2000. Specifically, the transfer layer of the adhesive sheet was bonded to a stainless steel plate (arithmetic mean surface roughness Ra: 50 ± 25 nm) using a 2 kg roller with one reciprocating motion. After standing at 23°C for 30 minutes, the adhesive sheet was peeled off at a peeling angle of 180° and a peeling speed (tensile speed) of 300 mm/min for measurement. The adhesion of the transfer layer changes with irradiation with active energy rays and laser light. In this specification, "initial adhesion" refers to the adhesion before irradiation with active energy rays and laser light.

In one embodiment, the adhesive sheet has an adhesion force B (also referred to as adhesion force B after curing) of preferably 1 N/20 mm or less, more preferably 0.5 N/20 mm or less, even more preferably 0.2 N/20 mm or less, and particularly preferably 0.1 N/20 mm or less. This adhesion force B is measured at 23°C after the adhesive sheet is attached to the stainless steel plate and the transfer layer is irradiated with UV light at 300 mJ/ ^cm² . Within this range, an adhesive sheet with excellent releasability and minimal adhesive residue can be obtained. The lower limit of the adhesion force B after curing is, for example, 0.01 N/20 mm (preferably 0.001 N/20 mm). The above-mentioned ultraviolet irradiation is performed, for example, using an ultraviolet irradiation device (manufactured by Nitto Seiki Co., Ltd., trade name "UM-810"), by irradiating the transfer layer with ultraviolet rays (characteristic wavelength: 365 nm, cumulative light intensity: 300 mJ/ ^cm2 ). The ultraviolet irradiation can be performed from the adhesive layer side.

The ratio of the adhesive strength I at 23°C when the adhesive layer is bonded to glass to the adhesive strength B of the transfer layer after curing (Adhesion I/Adhesion B after curing) is 5 or greater. In other words, in the adhesive sheet, the adhesive strength B after curing is 0.2 times or less (preferably 0.1 times or less, more preferably 0.05 times or less, and even more preferably 0.005 times or less) of the adhesive strength I. By specifying (Adhesion I/Adhesion B after curing) in this manner, the deformation of each layer caused by laser light irradiation can be optimized, resulting in an adhesive sheet with excellent releasability by laser light irradiation. Such an adhesive sheet can achieve reliable releasability within a narrow range. (Adhesion I/Adhesion B after curing) is preferably 10 or greater, more preferably 20 or greater, and even more preferably 200 or greater. Within this range, the aforementioned effects of the present invention become significant. The upper limit of (Adhesion I/Adhesion B after curing) is, for example, 1000, preferably 5000, and even more preferably 10000. In other words, in the adhesive sheet described above, Adhesion B after curing can be at least 0.0001 times Adhesion I.

The ratio of the initial adhesion force A of the transfer layer to the adhesion force B of the transfer layer after curing (initial adhesion force A/adhesion force B after curing) is preferably 5 or greater, more preferably 10 or greater, even more preferably 10-100, and even more preferably 30-80. Within this range, an adhesive sheet having an excellent balance between adherence and releasability can be obtained.

In the adhesive sheet, the gripping force of the adhesive layer and the layers disposed in contact with the adhesive layer (e.g., transfer layer, substrate, other layers) at 23°C is preferably 2 N/20 mm or greater, more preferably 4 N/20 mm or greater, even more preferably 6 N/20 mm or greater, and particularly preferably 8 N/20 mm or greater. The upper limit of this gripping force is, for example, 30 N/20 mm (preferably 50 N/20 mm). The gripping force is measured by peeling the adhesive layer from the adjacent layer at 23°C, a peeling angle of 180°, and a peeling speed (tensile speed) of 300 mm/min.

In the adhesive sheet, the gripping force of the layers disposed in contact with the transfer layer (e.g., adhesive layer, substrate, other layers) and the transfer layer at 23°C is preferably 2 N/20 mm or greater, more preferably 4 N/20 mm or greater, even more preferably 6 N/20 mm or greater, and particularly preferably 8 N/20 mm or greater. The upper limit of this gripping force is, for example, 30 N/20 mm (preferably 50 N/20 mm). The gripping force is measured by peeling the transfer layer from the adjacent layer at 23°C, a peel angle of 180°, and a peeling speed (tensile speed) of 300 mm/min.

The transmittance of the adhesive sheet of the present invention at a wavelength of 248 nm is preferably 50% or less, more preferably 30% or less, further preferably 10% or less, and particularly preferably 5% or less. In one embodiment, the transmittance of the adhesive sheet at a wavelength of 248 nm can be controlled by the transmittance of the light through the adhesive layer and/or the substrate. Specifically, the transmittance is controlled by adjusting the components of the adhesive layer (e.g., the type of base polymer; the type of additives such as adhesive imparting agents and crosslinking agents; and their blending amounts, etc.), the thickness of the adhesive layer, the constituent materials of the substrate, and the thickness of the substrate. In the present invention, by reducing the transmittance, strain in the adhesive layer and/or the substrate can be promoted, thereby reducing the laser output during peeling. Because the adhesive sheet of this invention exhibits releasability even with low-output laser light, its use can reduce damage to the adherend during peeling, preventing damage to the adherend. The lower the transmittance at a wavelength of 248 nm, the better, with a lower limit of, for example, 0.5% (preferably 0%).

The adhesive sheet of the present invention preferably has a transmittance of 50% or greater at a wavelength of 365 nm, more preferably 60% or greater, and even more preferably 70% or greater. Within this range, the adhesive sheet can be effectively cured by the transfer layer irradiated with active energy rays. The higher the transmittance of the adhesive sheet at a wavelength of 365 nm, the better. The upper limit is, for example, 95% (preferably 100%).

The adhesive sheet of the present invention preferably has a haze value of 70% or less, more preferably 65% or less. Within this range, the transfer layer of the adhesive sheet can be effectively cured by irradiation with active energy rays. In one embodiment, the haze value of the adhesive sheet is 20% or less. The lower the haze value of the adhesive sheet, the better, with a lower limit of 0.1%, for example.

The thickness of the adhesive sheet is preferably 1 μm to 300 μm, more preferably 5 μm to 200 μm. In one embodiment, the thickness of the adhesive sheet is 30 μm or less. A thinner adhesive sheet can easily transfer strain generated in the adhesive layer to the transfer layer, resulting in an adhesive sheet with excellent releasability.

When the adhesive sheet further includes a substrate and/or any other appropriate layers, the distance between the adhesive layer and the transfer layer is preferably less than 50 μm, more preferably less than 30 μm, even more preferably less than 25 μm, and particularly preferably less than 10 μm. Within this range, strain generated in the adhesive layer is easily transferred to the transfer layer, resulting in an adhesive sheet with excellent releasability.

B. Transfer Layer The thickness of the transfer layer is preferably 1 μm to 30 μm, more preferably 2 μm to 20 μm, and even more preferably 3 μm to 10 μm. Within this range, the aforementioned effects are most pronounced.

The initial compression modulus A of the transfer layer at 23°C is preferably 0.1 MPa or greater and less than 14 MPa, more preferably 0.1 MPa to 10 MPa, and even more preferably 0.2 MPa to 8 MPa. Within this range, an adhesive sheet with excellent fixation can be obtained. The compression modulus can be measured by a single compression method at 23°C at an compression speed of 10 nm/s and a compression depth of 100 nm. The adhesion of the transfer layer will change due to irradiation with active energy rays and laser light, but in this specification, "initial compression modulus A" means the adhesion before irradiation with active energy rays and laser light.

The transfer layer preferably has an indentation modulus B (also called post-curing modulus B) of 14 MPa or greater at 23°C after irradiation with 300 mJ/ ^cm² of UV light, more preferably 15 MPa or greater, even more preferably 20 MPa or greater, and particularly preferably 50 MPa or greater. This range yields an adhesive sheet with excellent releasability. It also prevents contamination of the adherend during peeling. The upper limit of the post-curing modulus B at 23°C is, for example, 500 MPa (preferably 300 MPa).

The transfer layer preferably has an indentation modulus (B) at 23°C after irradiation with 300 mJ/ ^cm² of UV light that is at least 20 times, more preferably at least 30 times, even more preferably 30 to 1000 times, and particularly preferably 50 to 200 times, of the transfer layer's initial indentation modulus (A) at 23°C. Within this range, an adhesive sheet exhibiting an excellent balance between adherence and release properties can be obtained.

The transfer layer preferably has an indentation modulus (B) at 23°C of at least five times the indentation modulus (I) of the adhesive layer at 23°C after irradiation with 300 mJ/ ^cm² of UV light, more preferably at least 10 times, further preferably 50 to 5000 times, and particularly preferably 100 to 3000 times. Within this range, deformation of each layer caused by laser irradiation can be mitigated, resulting in an adhesive sheet with excellent releasability upon laser irradiation. Such an adhesive sheet can achieve reliable releasability within a narrow range.

In one embodiment, the transfer layer includes an active energy ray-curable adhesive. The active energy ray-curable adhesive may further contain an ultraviolet absorber and/or a photopolymerization initiator.

(Active Energy Ray-Curing Adhesive) In one embodiment, an active energy ray-curing adhesive (A1) is used that contains a base polymer as a matrix and an active energy ray-reactive compound (monomer or oligomer) capable of bonding to the base polymer. In another embodiment, an active energy ray-curing adhesive (A2) is used that contains an active energy ray-reactive polymer as a base polymer. Preferably, the base polymer has a functional group that reacts with a photopolymerization initiator. Examples of such functional groups include hydroxyl groups and carboxyl groups.

Examples of base polymers that can be used in the adhesive (A1) include rubber-based polymers such as natural rubber, polyisobutylene rubber, styrene-butadiene rubber, styrene-isoprene-styrene block copolymer rubber, reclaimed rubber, butyl rubber, polyisobutylene rubber, and nitrile rubber (NBR); silicone-based polymers; and acrylic polymers. These polymers can be used alone or in combination of two or more. Acrylic polymers are preferred.

Examples of acrylic polymers include homopolymers or copolymers of alkyl (meth)acrylates, such as alkyl (meth)acrylates, cycloalkyl (meth)acrylates, and aryl (meth)acrylates; and copolymers of such alkyl (meth)acrylates and other copolymerizable monomers. Examples of alkyl (meth)acrylates include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, amyl, isoamyl, hexyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, decyl, isodecyl, undecyl, dodecyl (i.e., lauryl), tridecyl, tetradecyl, hexadecyl, octadecyl, and eicosyl (meth)acrylates. Examples of cycloalkyl (meth)acrylates include cyclopentyl and cyclohexyl (meth)acrylates. Examples of the aryl (meth)acrylate include phenyl (meth)acrylate and benzyl (meth)acrylate. The content of the structural units derived from the alkyl-containing (meth)acrylate is preferably 40 parts by weight or more, more preferably 60 parts by weight or more, based on 100 parts by weight of the base polymer.

Examples of the aforementioned other copolymerizable monomers include monomers containing carboxyl groups, acid anhydride monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid 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 monomers containing a hydroxyl group 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 monomers containing a glycidyl group include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate. Examples of monomers containing sulfonic acid groups include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of monomers containing phosphoric acid groups include 2-hydroxyethylacryloyl phosphate. Examples of acrylamide include N-acryloylisothiazolinone. These monomers may be used alone or in combination of two or more. The content of the structural units derived from the 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.

Acrylic polymers may contain structural units derived from multifunctional monomers to form a cross-linked structure within the polymer backbone. Examples of such multifunctional 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, trihydroxymethylpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy (meth)acrylate (i.e., polyglycidyl (meth)acrylate), (meth)acrylate polyesters, and urethane (meth)acrylates. These monomers may be used alone or in combination. The content of the structural units derived from the multifunctional monomer is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, based on 100 parts by weight of the base polymer.

The weight average molecular weight of the acrylic polymer is preferably 100,000 to 3,000,000, more preferably 200,000 to 2,000,000. The weight average molecular weight can be measured by GPC (Gel Permeation Chromatography) (solvent: THF (tetrahydrofuran)).

Examples of the active energy ray-reactive compound that can be used as the binder (A1) include photoreactive monomers or oligomers having a functional group having a polymerizable carbon-carbon multiple bond, such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, and an ethynyl group. Specific examples of the photoreactive monomer include esters of (meth)acrylic acid and polyols such as trihydroxymethylpropane tri(meth)acrylate, tetrahydroxymethylmethane 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, and polyethylene glycol di(meth)acrylate; multifunctional urethane (meth)acrylate; epoxy (meth)acrylate; and oligoester (meth)acrylate. Monomers such as methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), and m-isopropenyl-α,α-dimethylbenzyl isocyanate can also be used. Specific examples of photoreactive oligomers include dimers to pentamers of the above monomers. The molecular weight of the photoreactive oligomer is preferably 100 to 3000.

Furthermore, the active energy ray-reactive compound may be a monomer such as epoxidized butadiene, glycidyl methacrylate, acrylamide, or vinyl siloxane, or an oligomer containing the monomer.

Furthermore, a mixture of an organic salt such as an onium salt and a compound containing multiple heterocyclic rings within the molecule can also be used as the active energy ray-reactive compound. In this mixture, the organic salt is cleaved upon exposure to active energy rays (e.g., ultraviolet light or electron beams), generating ions. These ions act as initiators, initiating a ring-opening reaction of the heterocyclic rings, thereby forming a three-dimensional network structure. Examples of such organic salts include iodonium salts, phosphonium salts, antimony salts, stibnium salts, and borate salts. Examples of the heterocyclic ring in the aforementioned compound having a plurality of heterocyclic rings in the molecule include ethylene oxide, cyclohexane, cyclopentane, cyclothiopropane, and aziridine.

In the adhesive (A1), the active energy ray-reactive compound is preferably contained in an amount of 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, based on 100 parts by weight of the base polymer.

Examples of the active energy ray-reactive polymer (base polymer) included in the adhesive (A2) include polymers having functional groups with carbon-carbon multiple bonds, such as acryloyl, methacryloyl, vinyl, allyl, and ethynyl groups. Specific examples of active energy ray-reactive polymers include polymers containing multifunctional (meth)acrylates; cationic photopolymerizable polymers; polymers containing cinnamic groups, such as polyvinyl cinnamate; diazotized aminophenol resins; and polyacrylamide.

In one embodiment, an active energy ray-reactive polymer can be used, wherein active energy ray-polymerizable carbon-carbon multiple bonds are introduced into the side chains, main chain, and/or main chain terminals of the acrylic polymer. As a method for introducing radiation-polymerizable carbon-carbon double bonds into the acrylic polymer, for example, the following method can be cited: after copolymerizing a raw monomer containing a monomer having a predetermined functional group (first functional group) to obtain the acrylic polymer, a compound having a predetermined functional group (second functional group) that reacts with the first functional group to form a bond and a radiation-polymerizable carbon-carbon double bond is subjected to a condensation reaction or an addition reaction with the acrylic polymer while maintaining the radiation-polymerizable carbon-carbon double bond.

Examples of combinations of the first functional group and the second functional group include a carboxyl group and an epoxy group, an epoxy group and a carboxyl group, a carboxyl group and an aziridine group, an aziridine group and a carboxyl group, a hydroxyl group and an isocyanate group, and an isocyanate group and a hydroxyl group. Of these combinations, from the perspective of ease of reaction tracking, the combination of a hydroxyl group and an isocyanate group or the combination of an isocyanate group and a hydroxyl group is preferred. Furthermore, the production of highly reactive isocyanate polymers is technically difficult. From the perspective of ease of production or acquisition of acrylic polymers, it is more preferred for the first functional group on the acrylic polymer side to be a hydroxyl group and the second functional group to be an isocyanate group. In this case, examples of isocyanate compounds having both a radiation-polymerizable carbon-carbon double bond and an isocyanate group as a second functional group include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate. Furthermore, the acrylic polymer having a first functional group preferably contains structural units derived from the above-mentioned hydroxyl-containing monomers, and more preferably contains structural units derived from ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, or diethylene glycol monovinyl ether.

The adhesive (A2) may further contain the active energy ray-reactive compound (monomer or oligomer).

The active energy ray-curable adhesive may contain a UV absorber and/or a photopolymerization initiator. Details of the UV absorber and photopolymerization initiator used are described below.

In one embodiment, the active energy ray-curable adhesive may contain a photosensitizer. Examples of the photosensitizer include: "UVS-581" manufactured by Kawasaki Chemical Industries, Ltd., 9,10-diethoxyanthracene (e.g., "UVS-1101" manufactured by Kawasaki Chemical Industries, Ltd.). Other examples of the photosensitizer include: 9,10-dibutoxyanthracene (e.g., "UVS-1331" manufactured by Kawasaki Chemical Industries, Ltd.), 2-isopropyl-9-oxysulfonylsulfonate, , benzophenone, 9-oxosulfuron Derivatives, and 4,4'-bis(dimethylamino)benzophenone, etc. As 9-oxosulfuron Derivatives, for example, ethoxycarbonyl 9-oxosulfonium , isopropyl 9-oxysulfonium wait.

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, relative to 100 parts by weight of the base polymer.

The active energy ray-curable adhesive preferably contains a crosslinking agent. Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, and amine crosslinking agents.

The content of the crosslinking agent is preferably 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight, relative to 100 parts by weight of the base polymer of the adhesive.

In one embodiment, an isocyanate crosslinking agent is preferably used. Isocyanate crosslinking agents are preferred because they can react with various functional groups. Specific examples of the isocyanate crosslinking agent include: low-order aliphatic polyisocyanates such as butyl diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentyl diisocyanate, cyclohexyl diisocyanate, and isophorone diisocyanate; aromatic isocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylenediisocyanate; trihydroxymethylpropane/toluene diisocyanate trimer adduct (produced by Dongsoo Co., Ltd., trade name "Coronate L"), trihydroxymethylpropane/hexamethylene diisocyanate trimer adduct (produced by Dongsoo Co., Ltd., trade name "Coronate Isocyanate adducts such as the isocyanurate of hexamethylene diisocyanate (manufactured by Dongsoo Co., Ltd., trade name "Coronate HX") and the like are also suitable. A crosslinking agent having three or more isocyanate groups is preferably used.

Active energy ray-curable adhesives may further contain any appropriate additives as needed. Examples of such additives include active energy ray polymerization accelerators, free radical scavengers, coupling agents (e.g., silane coupling agents), adhesion promoters, plasticizers (e.g., trimellitate-based plasticizers, pyromellitate-based plasticizers, etc.), pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, light stabilizers, exfoliation modifiers, softeners, surfactants, flame retardants, antioxidants, particles, and ultraviolet absorbers.

(Photopolymerization initiator) Any appropriate initiator can be used as the photopolymerization initiator. Examples of the photopolymerization initiator include: α-ketoalcohol 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; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-oxo-1-propane -1-ketone and other acetophenone compounds; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisole methyl ether; ketone compounds such as benzoyl dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; optically active oxime compounds such as 1-benzophenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; 9-oxysulfonium , 2-chloro-9-oxysulfuronium , 2-methyl 9-oxosulfuronium , 2,4-dimethyl 9-oxosulfuronium , isopropyl 9-oxysulfonium , 2,4-dichloro-9-oxysulfuronium , 2,4-diethyl 9-oxosulfuron , and 2,4-diisopropyl 9-oxysulfonium 9-Oxosulfuronium compounds; camphorquinone; halogenated ketones; acylphosphine oxides; and acylphosphonates. The amount of the photopolymerization initiator used can be set to any appropriate amount.

In one embodiment, a photopolymerization initiator having a maximum absorption wavelength in the range of 400 nm or less (preferably 380 nm or less, more preferably 340 nm or less) can be used.

The amount of the photopolymerization initiator used can be set to any appropriate amount.

Commercially available photopolymerization initiators may be used. For example, photopolymerization initiators having a maximum absorption wavelength in the range of 400 nm or less include BASF products sold under the trade names "Irgacure 127," "Irgacure 369," "Irgacure 369E," "Irgacure 379," "Irgacure 379EG," "Irgacure 819," "Irgacure TOP," "Irgacure 784," and "Irgacure OXE01."

C. Adhesive Layer The thickness of the adhesive layer is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. Within this range, the aforementioned effects are significant. The lower limit of the adhesive layer thickness is, for example, 1 μm (preferably 0.5 μm).

The compression modulus (I) of the adhesive layer at 23°C is preferably 0.05 MPa to 20 MPa, more preferably 0.08 MPa to 10 MPa, and even more preferably 0.08 MPa to 5 MPa. Within this range, deformation of each layer caused by laser irradiation can be adaptively controlled, resulting in an adhesive sheet with excellent releasability upon laser irradiation. Such an adhesive sheet can achieve reliable releasability within a narrow range.

The light transmittance of the adhesive layer at a wavelength of 248 nm is preferably 50% or less, more preferably 30% or less, further preferably 10% or less, and particularly preferably 5% or less. The lower the light transmittance of the adhesive layer at a wavelength of 248 nm, the better, and its lower limit is, for example, 0.5% (preferably 0%).

The light transmittance of the adhesive layer at a wavelength of 365 nm is preferably 50% or greater, more preferably 60% or greater, and even more preferably 70% or greater. The higher the light transmittance of the adhesive layer at a wavelength of 365 nm, the better. The upper limit is, for example, 95% (preferably 100%).

The adhesive sheet of the adhesive layer preferably has a haze value of 70% or less, more preferably 65% or less. In one embodiment, the haze value of the adhesive layer is 20% or less. The lower the haze value of the adhesive layer, the better, and its lower limit is, for example, 0.1%.

The adhesive layer contains any suitable adhesive. Any suitable adhesive can be used as long as the effects of the present invention can be achieved. For example, a pressure-sensitive adhesive can be used as the adhesive.

(Pressure-Sensitive Adhesives) Examples of pressure-sensitive adhesives include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives. Of these, acrylic adhesives and rubber adhesives are preferred, with acrylic adhesives being more preferred. These adhesives may be used alone or in combination of two or more. In one embodiment, from the perspective of UV absorption, an adhesive containing a base polymer having an aromatic ring and/or a double bond may be used. In this regard, acrylic adhesives are preferably used.

Examples of the acrylic adhesive include acrylic adhesives having an acrylic polymer (homopolymer or copolymer) as a base polymer, wherein the acrylic polymer uses one or more alkyl (meth)acrylates as monomer components. Specific examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and nonyl (meth)acrylate. C1-20 alkyl (meth)acrylates such as octadecyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate are preferably used. Among them, alkyl (meth)acrylates having a linear or branched alkyl group with 4 to 18 carbon atoms are preferably used.

The acrylic polymer may also contain units corresponding to other monomer components copolymerizable with the alkyl (meth)acrylate, as needed, to improve cohesion, heat resistance, crosslinking, etc. Examples of such monomer components include: monomers containing carboxyl groups such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itaconic anhydride; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, and (meth) Monomers containing hydroxyl groups such as hydroxydecyl acrylate, hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate; monomers containing sulfonic acid groups such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; (meth)acrylamide, N,N-dimethyl(meth)acrylate (N-substituted)amide monomers such as enamide, N-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, and N-hydroxymethylpropane (meth)acrylamide; (meth)acrylamide alkyl (meth)acrylate monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and tert-butylaminoethyl (meth)acrylate; methoxyethyl (meth)acrylate, ethyl (meth)acrylate (Meth)acrylate monomers such as methoxyethyl ester; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; N-methyliconimide, N-ethyliconimide, N-butyliconimide, N-octyliconimide, N-2-ethylhexyliconimide, N-cyclohexyliconimide, and N-laurylmaleimide. Iconimide monomers such as 1,2-dioxadiazole; N-(meth)acryloyloxymethylenebutaneimide, N-(meth)acryloyl-6-oxyhexamethylenebutaneimide, and N-(meth)acryloyl-8-oxyoctamethylenebutaneimide; vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinyl Vinyl monomers such as pyrimidine, vinylpiperidinium, vinylpyrrolidone, vinylpyrrole, vinylimidazole, vinyloxazole, vinylisocyanate, N-vinylcarboxamides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; acrylic monomers containing epoxy groups such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate Acrylates, methoxyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate and other ethylene glycol acrylate monomers; (meth)acrylate tetrahydrofurfuryl, fluorinated (meth)acrylate, (meth)acrylate silicone esters and other acrylate monomers having heterocyclic rings, halogen atoms, and silicon atoms; hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate and other ) acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; olefin monomers such as isoprene, butadiene, and isobutylene; and vinyl ether monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more.

Examples of the rubber-based adhesive include those based on the following rubber polymers: natural rubber; polyisoprene rubber, styrene-butadiene (SB) rubber, styrene-isoprene (SI) rubber, styrene-isoprene-styrene block copolymer (SIS) rubber, styrene-butadiene-styrene block copolymer (SBS) rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS) rubber, styrene-ethylene-propylene-styrene block copolymer (SEPS) rubber, styrene-ethylene-propylene block copolymer (SEP) rubber, recycled rubber, butyl rubber, polyisobutylene, and synthetic rubbers such as modified forms thereof.

The pressure-sensitive adhesive may contain any appropriate additives as needed. Examples of such additives include crosslinking agents, adhesion promoters (e.g., rosin-based adhesion promoters, terpene-based adhesion promoters, and hydrocarbon-based adhesion promoters), plasticizers (e.g., trimellitic acid ester-based plasticizers and pyromellitic acid ester-based plasticizers), pigments, dyes, anti-aging agents, conductive materials, antistatic agents, light stabilizers, stripping modifiers, softeners, surfactants, flame retardants, antioxidants, ultraviolet absorbers, and particles.

Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, and peroxide crosslinking agents. Urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, and amine crosslinking agents are also included. Among these, isocyanate crosslinking agents and epoxy crosslinking agents are preferred. In one embodiment, from the perspective of UV absorption, a crosslinking agent having an aromatic ring and/or double bond (e.g., an aromatic isocyanate crosslinking agent) can be used.

Specific examples of the isocyanate crosslinking agent include: lower aliphatic polyisocyanates such as butyl diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentyl diisocyanate, cyclohexyl diisocyanate, and isophorone diisocyanate; aromatic isocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylenediisocyanate; trihydroxymethylpropane/toluene diisocyanate trimer adduct (produced by Dongsoo Co., Ltd., trade name "Coronate L"), trihydroxymethylpropane/hexamethylene diisocyanate trimer adduct (produced by Dongsoo Co., Ltd., trade name "Coronate Isocyanate adducts such as hexamethylene diisocyanate ("HL"), and the isocyanurate of hexamethylene diisocyanate (manufactured by Dongsoo Co., Ltd., trade name "Coronate HX"). The content of the isocyanate crosslinking agent can be set to any appropriate amount based on the desired adhesion, typically 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, relative to 100 parts by weight of the base polymer.

Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1500NP"), ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 40E"), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 70P"), polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "EPIOL E-400"), polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "EPIOL P-200"), sorbitol polyglycidyl ether (manufactured by Nagase Chemicals, trade name "DENACOL EX-611"), glycerol polyglycidyl ether (manufactured by Nagase Chemicals, trade name "DENACOL EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase Chemicals, trade name "DENACOL EX-512), sorbitan polyglycidyl ether, trihydroxymethylpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, triglycidyl-tri(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy crosslinking agent can be set to any appropriate amount depending on the desired adhesion, and is typically 0.01 to 10 parts by weight, more preferably 0.03 to 5 parts by weight, relative to 100 parts by weight of the base polymer.

Examples of the aforementioned tackifiers include rosin resins (e.g., rosin ester resins), terpene resins (e.g., terpene-phenol copolymers (terpene-modified phenol resins), hydrogenated terpene resins, coumarone-indene resins, alicyclic saturated hydrocarbon resins, petroleum resins (e.g., aliphatic/aromatic copolymerized petroleum resins, aromatic petroleum resins, and other hydrocarbon petroleum resins), and phenolic resins. In one embodiment, from the perspective of UV absorption, a crosslinking agent having an aromatic ring and/or double bond (e.g., a rosin resin) can be used. The content of the adhesion-imparting agent can be set to any appropriate amount according to the required adhesion, and is typically 1 to 50 parts by weight, more preferably 10 to 30 parts by weight, relative to 100 parts by weight of the base polymer.

D. Substrate The substrate may contain any appropriate resin. Examples of such resins include polyolefin resins such as polyethylene resins, polypropylene resins, polybutylene resins, and polymethylpentene resins, polyurethane resins, polyester resins, polyimide resins, polyetherketone resins, polystyrene resins, polyvinyl chloride resins, polyvinylidene chloride resins, fluorine resins, silicone resins, cellulose resins, and ionic polymer resins. Polyolefin resins are preferred.

In one embodiment, the substrate comprises at least one resin selected from the group consisting of polyethylene terephthalate resins, polyimide resins, polystyrene resins, and polycarbonate resins. Substrates comprising these resins are advantageous in that they have lower transmittance at a wavelength of 248 nm.

The thickness of the substrate is preferably 2 μm to 300 μm, more preferably 2 μm to 100 μm, and even more preferably 2 μm to 50 μm. In one embodiment, the thickness of the substrate is less than 50 μm, more preferably 30 μm or less, even more preferably 20 μm or less, particularly preferably 10 μm or less, and most preferably 5 μm or less. A thinner substrate allows strain generated in the adhesive layer to be easily transferred to the transfer layer, resulting in an adhesive sheet with excellent releasability.

The substrate's compression modulus at 23°C is preferably 5000 MPa or less, more preferably 3000 MPa or less, and even more preferably 1000 MPa or less. Within this range, the substrate is less susceptible to strain generated by the adhesive layer and readily transmits strain to the transfer layer. The lower limit of the substrate's compression modulus at 23°C is preferably 1 MPa, more preferably 5 MPa, and even more preferably 10 MPa. Within this range, an adhesive sheet with moderate rigidity and excellent handleability is obtained.

The total light transmittance of the substrate is preferably 70% or higher, more preferably 80% or higher, further preferably 90% or higher, and particularly preferably 95% or higher. The upper limit of the total light transmittance of the substrate is, for example, 98% (preferably 99%).

E. Adhesive Sheet Manufacturing Method The adhesive sheet can be manufactured by any suitable method. For example, the adhesive sheet can be obtained by separately coating the adhesive described above on a substrate or a release liner to form an adhesive layer and a transfer layer. Various coating methods can be used, including bar coating, air knife coating, gravure coating, reverse gravure coating, reverse roll coating, lip coating, die coating, dip coating, offset printing, flexographic printing, and screen printing. Alternatively, an adhesive sheet can be formed by forming an adhesive layer on a release liner, forming a transfer layer on another release liner, and laminating these or laminating them to a substrate.

F. Adhesive Sheet Usage Method The adhesive sheet of the present invention can be used to temporarily secure any suitable workpiece (e.g., electronic components) during processing and/or transport. Examples of methods for using the adhesive sheet of the present invention include: (i) attaching the adhesive layer to a support; (ii) attaching the workpiece to the transfer layer of the adhesive sheet to secure it; (iii) processing or transporting the workpiece; (iv) irradiating the adhesive sheet with active energy radiation (e.g., ultraviolet radiation) to reduce the adhesive strength of the transfer layer side of the adhesive sheet; and (iv) irradiating the area where releasability is desired with laser light to induce strain in the adhesive layer. This method enables the workpiece to be released by natural falling. Furthermore, when temporarily securing multiple workpieces, it is possible to peel only a portion of them. The adhesive sheet of the present invention reduces the adhesive force to a level that allows the workpiece to fall off naturally, allowing even very small workpieces (e.g., 50 μm square) to be peeled off individually.

As the support in (i) above, a glass plate can be used, for example. The support is preferably light-transmissive. The total light transmittance of the support is, for example, 50% or more, preferably 80% or more.

In one embodiment, the active energy rays in the above-mentioned (iii) are irradiated from the adhesive layer side (substantially the support side) of the adhesive sheet.

In one embodiment, the laser light in (iv) above is irradiated from the adhesive layer side (substantially the support side) of the adhesive sheet.

In one embodiment, the wavelength of the laser light is 200 nm to 300 nm. [Example]

The present invention is described in detail below using examples, but the present invention is not limited to these examples. The testing and evaluation methods of the examples are described below. Furthermore, unless otherwise specified, "parts" and "%" are by weight.

(1) Adhesion of adhesive layer to glass I After peeling off the PET (Polyethylene terephthalate) separator film on the transfer layer side of the adhesive sheet, it was laminated to a 25 μm thick PET (Lumirror S10 manufactured by Toray). The PET separator film on the other side was then peeled off and laminated to a glass plate (S200423 manufactured by Matsunami Glass Industries Co., Ltd.) by moving a 2 kg roller back and forth once. The adhesion was measured using the method according to JIS Z 0237:2000 (peeling angle 180°, peeling speed (tensile speed) 300 mm/min, measurement temperature: 23°C).

(2) Adhesion of the transfer layer to the stainless steel plate: After peeling off the PET separator film on the adhesive layer side of the adhesive sheet (in Comparative Example 2, it was a PET separator film bonded to the transfer layer), the sheet was bonded to 25 μm thick PET (Lumirror S10 manufactured by Toray). The PET separator film on the other side was then peeled off and bonded to SUS304 (Steel Use Stainless 304, 304 stainless steel) by moving a 2 kg roller back and forth once. The adhesion was measured using the method according to JIS Z 0237:2000 (peeling angle 180°, peeling speed (tensile speed) 300 mm/min, measuring temperature: 23°C) and was taken as the initial adhesion A. Using the same method, the adhesive sheet was bonded to SUS304 and then irradiated with ultraviolet light (specific wavelength: 365 nm, cumulative light intensity: 300 mJ/cm ² ) from the adhesive layer side using a UV irradiation device (Nitto Seiki, trade name "UM-810"). The adhesive strength was then measured in the same manner and designated as the post-curing adhesive strength B.

(3) Indentation Modulus (Before Curing) The indentation modulus of the adhesive layer and transfer layer was measured using a TriboIndenter TI-950 manufactured by Hysitron. The measurement was performed using a single indentation method at 23°C, with an indentation speed of 10 nm/s and an indentation depth of 100 nm.

(4) Pressed elastic modulus (after curing) After peeling off the PET separator film on the adhesive layer side of the adhesive sheet (in Comparative Example 2, one of the PET separator films bonded to the transfer layer) and bonding it to a large glass slide (Matsunami Glass, trade name "S9111") using a manual roller. Using a UV irradiation device (Nitto Seiki, trade name "UM-810"), the entire surface of the glass slide of the obtained sample was irradiated with ultraviolet light from a high-pressure mercury lamp (specific wavelength: 365 nm, cumulative light intensity: 300 mJ/ ^cm2 ). Afterwards, the other PET separator was peeled off to expose the transfer layer. The indentation modulus was measured using a Hysitron TriboIndenter TI-950. The measurement was performed using a single indentation method at 23°C, with an indentation speed of 10 nm/s and an indentation depth of 100 nm.

(5) Haze value Use a haze meter (manufactured by Murakami Color Technology Laboratory, trade name "HAZE METER HM-150") to measure the haze value of the adhesive sheet.

(6) Light transmittance Using a spectrophotometer (manufactured by Hitachi High-Tech Science, trade name "Spectrophotometer U-4100"), the light transmittance of the adhesive sheet at a wavelength of 365 nm and 248 nm was measured.

(7) Releasability (Transferability) After peeling off the PET separator film on the adhesive layer side of the adhesive sheet (in Comparative Example 2, it is one of the PET separator films attached to the transfer layer), it was attached to a quartz plate (manufactured by AS ONE) using a manual roller. After that, the PET separator film on the other side was peeled off, and a 125 μm × 100 μm silicon wafer was attached to the adhesive surface of the transfer layer. Using an ultraviolet irradiation device (manufactured by Nitto Seiki, trade name "UM-810"), the entire surface of the quartz plate was irradiated with ultraviolet rays from a high-pressure mercury lamp (specific wavelength: 365 nm, cumulative light intensity: 300 mJ/ ^cm2 ). Afterwards, only the target component position was irradiated (1 plus per chip) with 248 nm laser light (irradiation area: 130 μm × 105 μm, output 100 mJ/cm ² ) from the quartz plate side. Those that naturally fell off were evaluated as passing (0), while those that did not naturally fall off were evaluated as failing (×).

(8) Deformation The deformation of the transfer layer surface after laser irradiation was observed under a microscope. Cases where a significant color difference was observed between the laser irradiated area and other areas were evaluated as unacceptable (×), and cases where no significant color difference was observed were evaluated as acceptable (○). In addition, a microscope photograph of the transfer layer surface of Example 1 (evaluation of deformation: acceptable) is shown in Figure 2(a), and a microscope photograph of the transfer layer surface of Comparative Example 1 (evaluation of deformation: unacceptable) is shown in Figure 2(b).

(9) Residue of adhesive Visually inspect the glass plate after the evaluation of "(1) Adhesion of adhesive layer to glass" above. If there is residual adhesive layer on the glass, evaluate it as unacceptable (×); if there is no residual adhesive layer on the glass, evaluate it as acceptable (○).

[Production Example 1] Preparation of Acrylic Polymer I A monomer composition was prepared by mixing 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of butyl acrylate, 3 parts by weight of acrylic acid, and 1 part by weight of 4-hydroxybutyl acrylate. Next, nitrogen gas was introduced into a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer. Under a nitrogen atmosphere, 103.1 parts by weight of the monomer composition, 0.2 parts by weight of benzoyl peroxide (BPO), and 150 parts by weight of toluene were added. The mixture was stirred at 60°C for 6 hours to obtain an acrylic polymer solution I containing acrylic polymer I.

[Production Example 2] Preparation of Acrylic Polymer II A monomer composition was prepared by mixing 70 parts by weight of ethyl acrylate, 30 parts by weight of 2-hydroxyethyl acrylate, 5 parts by weight of methyl methacrylate, and 4 parts by weight of hydroxyethyl acrylate. Next, nitrogen gas 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 toluene, 109 parts by weight of the monomer composition, and 0.2 parts by weight of benzoyl peroxide (BPO) were added. The mixture was stirred at 60°C for 6 hours to obtain an acrylic polymer solution II containing an acrylic polymer II with a weight-average molecular weight of 500,000.

[Preparation Example 3] Preparation of Acrylic Polymer III A monomer composition was prepared by mixing 100 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of acrylic acid, and 0.01 parts by weight of trihydroxymethylpropane triacrylate. Next, nitrogen gas was introduced into a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer. Under a nitrogen atmosphere, 102.01 parts by weight of the monomer composition, 0.2 parts by weight of benzoyl peroxide (BPO), and 189 parts by weight of toluene were added. The mixture was stirred at 60°C for 7 hours to obtain an acrylic polymer solution III containing acrylic polymer III.

[Preparation Example 4] Preparation of Acrylic Polymer IV A monomer composition was prepared by mixing 100 parts by weight of butyl acrylate, 78 parts by weight of ethyl acrylate, and 40 parts by weight of hydroxyethyl acrylate. Next, nitrogen gas was introduced into a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer. Under a nitrogen atmosphere, 507 parts by weight of toluene, 218 parts by weight of the monomer composition, and 1.2 parts by weight of benzoyl peroxide (BPO) were added, and the mixture was stirred at 60°C for 5 hours. The mixture was then cooled to room temperature, and 42.6 parts by weight of 2-methacryloyloxyethyl isocyanate was added and allowed to react, thereby adding NCO groups to the terminal OH groups of the side chains of 2-hydroxyethyl acrylate in the copolymer, thereby obtaining an acrylic polymer solution IV containing an acrylic polymer IV having a carbon-carbon double bond at the terminal end.

[Production Example 5] Preparation of Acrylic Polymer V A monomer composition was prepared by mixing 100 parts by weight of 2-ethylhexyl acrylate, 25.5 parts by weight of acryloyl thiophene, and 18.5 parts by weight of hydroxyethyl acrylate. Next, nitrogen gas was introduced into a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer. Under a nitrogen atmosphere, 60 parts by weight of toluene, 144 parts by weight of the monomer composition, and 0.3 parts by weight of benzoyl peroxide (BPO) were added, and the mixture was stirred at 60°C for 4 hours. The mixture was then cooled to room temperature, and 12 parts by weight of 2-methacryloyloxyethyl isocyanate was added and allowed to react, thereby adding NCO groups to the terminal OH groups of the side chains of 2-hydroxyethyl acrylate in the copolymer, thereby obtaining an acrylic polymer solution V containing an acrylic polymer V having a carbon-carbon double bond at the terminal end.

[Preparation Example 6] Preparation of Acrylic Polymer VI A monomer composition was prepared by mixing 100 parts by weight of 2-methoxyethyl acrylate, 27 parts by weight of acryloyl thiophene, and 22 parts by weight of 2-hydroxyethyl acrylate. Next, nitrogen gas was introduced into a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer. Under a nitrogen atmosphere, 500 parts by weight of toluene, 149 parts by weight of the monomer composition, and 0.3 parts by weight of benzoyl peroxide (BPO) were added, and the mixture was stirred at 60°C for 5 hours. The mixture was then cooled to room temperature, and 24 parts by weight of 2-methacryloyloxyethyl isocyanate was added and reacted to form an NCO group at the terminal OH group of the side chain of 2-hydroxyethyl acrylate in the copolymer, yielding an acrylic polymer solution VI containing an acrylic polymer having a carbon-carbon double bond at the terminal end.

[Example 1] (Preparation of adhesive) To an acrylic polymer solution I containing 100 parts by weight of acrylic polymer I, 2 parts by weight of a crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate L") and 30 parts by weight of an adhesive-imparting resin (manufactured by Arakawa Chemical Industries, Ltd., trade name "D-125") were added to obtain an adhesive (1) for forming an adhesive layer. To an acrylic polymer solution IV containing 100 parts by weight of acrylic polymer IV, 3 parts by weight of a crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate L") and 10 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 127") were added to obtain an adhesive (A) for forming a transfer layer. (Adhesive Sheet) The adhesive (1) was applied to the silicone treated surface of a PET separator film (thickness: 38 μm), and then heated at 120°C for 2 minutes to form an adhesive layer with a thickness of 4 μm. Separately, the adhesive (A) was applied to the silicone treated surface of a PET separator film (thickness: 75 μm), and then heated at 120°C for 2 minutes to form a transfer layer with a thickness of 5 μm. An adhesive layer with a PET separator film attached was laminated to one side of a PET substrate (Toray Industries, trade name "Lumirror 2DC61," thickness: 2 μm). A transfer layer with a PET separator film attached was laminated to the other side, resulting in an adhesive sheet consisting of a PET separator film/adhesive layer/substrate/transfer layer/PET separator film. The resulting adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Example 2] An adhesive sheet was obtained in the same manner as in Example 1, except that acrylic polymer solution V containing 100 parts by weight of acrylic polymer V was used instead of acrylic polymer solution IV. The obtained adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Example 3] To an acrylic polymer solution VI containing 100 parts by weight of acrylic polymer VI, 5 parts by weight of a crosslinking agent (manufactured by Dongsoo Co., Ltd., trade name "Coronate L") and 10 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 127") were added to obtain an adhesive (C) for forming a transfer layer. Example 1 was similar to Example 1, except that adhesive (C) was used instead of adhesive (A) to form the transfer layer. An adhesive sheet was obtained. The obtained adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Example 4] To 100 parts by weight of acrylic polymer solution VI, 5 parts by weight of a crosslinking agent ("Coronate L," manufactured by Dongsoo Co., Ltd.), 10 parts by weight of a photopolymerization initiator ("Irgacure 127," manufactured by BASF), and 5 parts by weight of silica microparticles ("YA050C," manufactured by Yaduma Co., Ltd.) were added to obtain an adhesive (D) for forming a transfer layer. Example 1: An adhesive sheet was obtained by following the same procedures as in Example 1, except that adhesive (D) was used instead of adhesive (A) to form the transfer layer. The obtained adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Example 5] An adhesive sheet was obtained by following the same procedures as in Example 3, except that the adhesive layer thickness was changed to 20 μm. The obtained adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Example 6] (Preparation of Adhesive) The same operation as in Example 1 was performed to obtain an adhesive (1) for forming an adhesive layer. To an acrylic polymer solution VI containing 100 parts by weight of acrylic polymer VI, 5 parts by weight of a crosslinking agent (manufactured by Dongsoo Co., Ltd., trade name "Coronate L"), 10 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 127"), and 5 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 405", molecular weight: 583.8) were added to obtain an adhesive (E) for forming a transfer layer. (Adhesive sheet) The adhesive (1) was applied to the silicone treated surface of a PET separator film (thickness: 38 μm), and then heated at 120°C for 2 minutes to form an adhesive layer with a thickness of 4 μm. Separately, the adhesive (E) was applied to the silicone treated surface of a PET separator film (thickness: 75 μm), and then heated at 120°C for 2 minutes to form a transfer layer with a thickness of 5 μm. An adhesive layer with a PET separator film attached was laminated to one side of a PET substrate (Toray Industries, trade name "Lumirror S10," thickness: 25 μm). A transfer layer with a PET separator film attached was laminated to the other side, resulting in an adhesive sheet consisting of a PET separator film/adhesive layer/substrate/transfer layer/PET separator film. The resulting adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Example 7] An adhesive sheet was obtained by following the same procedures as in Example 3, except that the thickness of the transfer layer was changed to 25 μm. The obtained adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Example 8] (Preparation of Adhesive) 8.5 parts by weight of a crosslinking agent (manufactured by Dongsoo Co., Ltd., trade name "Coronate L") was added to an acrylic polymer solution II containing 100 parts by weight of an acrylic polymer II to obtain an adhesive (2) for forming an adhesive layer. The same operation as in Example 3 was performed to obtain an adhesive (C) for forming a transfer layer. (Adhesive Sheet) The adhesive (2) was applied to the silicone-treated surface of a PET separator film (thickness: 38 μm), and then heated at 120°C for 2 minutes to form an adhesive layer with a thickness of 4 μm. Separately, the aforementioned adhesive (C) was applied to the silicone-treated surface of a PET separator film (75 μm thick) and then heated at 120°C for 2 minutes to form a 5 μm thick transfer layer. The adhesive layer with the PET separator film attached was laminated to one side of a PET substrate (Toray Industries, trade name "Lumirror 2DC61," 2 μm thick), and the transfer layer with the PET separator film attached was laminated to the other side. This yielded an adhesive sheet consisting of PET separator film/adhesive layer/substrate/transfer layer/PET separator film. The resulting adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Comparative Example 1] (Preparation of Adhesive) 2 parts by weight of a crosslinking agent (manufactured by Dongsoo Co., Ltd., trade name "Coronate L") was added to an acrylic polymer solution III containing 100 parts by weight of an acrylic polymer III to obtain an adhesive (3) for forming an adhesive layer. The same operation as in Example 3 was performed to obtain an adhesive (C) for forming a transfer layer. (Adhesive Sheet) The adhesive (3) was applied to the silicone-treated surface of a PET separator film (thickness: 38 μm), and then heated at 120°C for 2 minutes to form an adhesive layer with a thickness of 4 μm. Separately, the aforementioned adhesive (C) was applied to the silicone-treated surface of a PET separator film (75 μm thick) and then heated at 120°C for 2 minutes to form a 5 μm thick transfer layer. The adhesive layer with the PET separator film attached was laminated to one side of a PET substrate (Toray Industries, trade name "Lumirror 2DC61," 2 μm thick), and the transfer layer with the PET separator film attached was laminated to the other side. This yielded an adhesive sheet consisting of PET separator film/adhesive layer/substrate/transfer layer/PET separator film. The resulting adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Comparative Example 2] (Adhesive Preparation) An adhesive (C) for forming a transfer layer was obtained by following the same procedures as in Example 3. (Adhesive Sheet) The adhesive (C) was applied to the silicone-treated surface of a PET separator film (75 μm thick) and then heated at 120°C for 2 minutes to form a 5 μm thick transfer layer. An additional PET separator film (38 μm thick) was laminated on the transfer layer to obtain an adhesive sheet consisting of a PET separator film/transfer layer/PET separator film.

[Comparative Example 3] To acrylic polymer solution I containing 100 parts by weight of acrylic polymer I, 2 parts by weight of a crosslinking agent (manufactured by Tosoh Co., Ltd., trade name "Coronate L") and 30 parts by weight of a tackifying resin (manufactured by Arakawa Chemical Industries, Ltd., trade name "D-125") were added to obtain an adhesive (F) for forming a transfer layer. An adhesive sheet was obtained by following the same procedures as in Example 1, except that adhesive (F) was used instead of adhesive (A) to form the transfer layer. The obtained adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Comparative Example 4] To an acrylic polymer solution V containing 100 parts by weight of acrylic polymer V, 3 parts by weight of a crosslinking agent (manufactured by Dongsoo Co., Ltd., trade name "Coronate L") and 0.5 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 127") were added to obtain an adhesive (G) for forming a transfer layer. Example 8 was repeated, except that adhesive (G) was used instead of adhesive (C) to form the transfer layer, to obtain an adhesive sheet. The obtained adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Comparative Example 5] (Preparation of Adhesive) The same operation as in Example 1 was performed to obtain an adhesive (1) for forming an adhesive layer. The same operation as in Comparative Example 3 was performed to obtain an adhesive (F) for forming a transfer layer. (Adhesive Sheet) The adhesive (1) was applied to the silicone-treated surface of a PET separator film (thickness: 38 μm), and then heated at 120°C for 2 minutes to form an adhesive layer with a thickness of 4 μm. In addition, the adhesive (F) was applied to the silicone-treated surface of a PET separator film (thickness: 75 μm), and then heated at 120°C for 2 minutes to form a transfer layer with a thickness of 5 μm. An adhesive layer with a PET separator film was laminated to one side of a PET substrate (Toray Industries, trade name "Lumirror S27," thickness: 75 μm). A transfer layer with a PET separator film was laminated to the other side. This produced an adhesive sheet consisting of a PET separator film/adhesive layer/substrate/transfer layer/PET separator film structure. The resulting adhesive sheet was subjected to the aforementioned evaluations. The results are shown in Table 1.

[Comparative Example 6] An adhesive sheet was obtained by following the same procedures as in Comparative Example 5, except that a PP (polypropylene) substrate (Toray Industries, trade name "Torayfan BO 12D-KW37," thickness: 12 μm) was used instead of a PET substrate (Toray Industries, trade name "Lumirror S27," thickness: 75 μm). The resulting adhesive sheet was evaluated as described above. The results are shown in Table 1.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Adhesive layer Acrylic polymer Kind I I I I I I I II III - I II I I Number of copies 100 100 100 100 100 100 100 100 100 100 100 100 100 Crosslinking agent Kind C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L Number of copies 2 2 2 2 2 2 2 8.5 2 2 8.5 2 2 Additives (adhesion enhancers) Kind D-125 D-125 D-125 D-125 D-125 D-125 D-125 - - D-125 - D-125 D-125 Number of copies 30 30 30 30 30 30 30 30 30 30 Thickness (μm) 4 4 4 4 20 4 4 4 4 4 4 4 4 substrate Kind PET PET PET PET PET PET PET PET PET PET PET PET PET PP Thickness (μm) 2 2 2 2 2 25 2 2 2 2 2 2 75 12 transfer layer Acrylic polymer Kind IV V VI VI VI VI VI VI VI VI I V I I Number of copies 100 100 100 100 100 100 100 100 100 100 100 100 100 100 Crosslinking agent Kind C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L C/L Number of copies 3 3 5 5 5 5 5 5 5 5 2 3 2 2 Photopolymerization initiator Kind Irg127 Irg127 Irg127 Irg127 Irg127 Irg127 Irg127 Irg127 Irg127 Irg127 - Irg127 - - Number of copies 10 10 10 10 10 10 10 10 10 10 0.5 additives Kind - - - YA050C - Tinuvin405 - - - - D-125 - D-125 D-125 Number of copies 5 5 30 30 30 thickness 5 5 5 5 5 5 25 5 5 5 5 5 5 5 evaluate Adhesive layer Adhesion to glass I (N/20 mm) 8.1 8.1 8.1 8.1 11.5 8.1 8.1 2.3 0.3 0.07 8.1 2.3 8.1 8.1 Elastic modulus I (MPa) 0.08 0.08 0.08 0.08 0.08 0.08 0.08 2.2 0.03 156 0.08 2.2 0.08 0.08 transfer layer Initial adhesion to SUS A (N/20 mm) 1.8 3.9 3.3 2.5 3.3 1.3 3.3 3.3 3.3 3.3 6.8 3.92 6.8 6.8 Adhesion strength of SUS after curing B (N/20 mm) 0.09 0.44 0.07 0.06 0.07 0.09 0.07 0.07 0.07 0.07 6.8 0.59 6.8 6.8 Elastic modulus before hardening (initial compression elastic modulus A) (MPa) 0.37 0.35 0.89 0.25 0.89 0.72 0.89 0.89 0.89 0.89 0.08 0.53 0.08 0.08 Elastic modulus B after hardening (MPa) 14 66 156 192 156 95 192 156 156 156 0.08 10 0.08 0.08 Adhesion I/Adhesion after curing B 90 18 116 135 165 90 116 33 4 1 1 4 1 1 Elastic modulus I/elastic modulus after hardening B 0.0054 0.0012 0.0005 0.0004 0.0005 0.0008 0.0004 0.0141 0.0002 1.0000 1.0000 0.2192 1.0000 1.0000 Whether there is deformation ○ ○ ○ ○ ○ ○ ○ ○ × × ○ ○ ○ ○ Transferability ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ × × × × Paste residue ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ × Adhesion ratio of transfer layer before and after curing 20 9 47 41 47 14 47 47 47 47 1 7 1 1 Elastic modulus ratio of transfer layer before and after curing 0.026 0.005 0.006 0.001 0.006 0.008 0.005 0.006 0.006 0.006 1.000 0.053 1.000 1.000 Haze (%) 1.0 0.8 4.7 6.0 3.0 2.6 0.4 0.8 1.9 4.6 1.0 4.4 9.1 1.2 365 nm transmittance (%) 88.1 88.0 87.1 85.6 87.1 52.6 81.2 88.8 88.5 97.1 88.6 87.8 81.37 90.93 248 nm transmittance (%) 1.3 0.0 1.6 0.0 1.3 0.7 1.0 1.1 0.6 5.6 1.2 1.4 1.58 3.45

10: Adhesive layer 20: Transfer layer 30: Base material 100: Adhesive sheet 200: Adhesive sheet

Figure 1(a) is a schematic cross-sectional view of an adhesive sheet according to one embodiment of the present invention. Figure 1(b) is a schematic cross-sectional view of an adhesive sheet according to another embodiment of the present invention. Figure 2(a) is a microscopic photograph of the transfer layer surface of Example 1. Figure 2(b) is a microscopic photograph of the transfer layer surface of Comparative Example 1.

10: Adhesive layer

20: Transfer layer

30: Base material

100: Adhesive sheet

200: Adhesive sheet

Claims (6)

An adhesive sheet comprising an adhesive layer and a transfer layer disposed on one side of the adhesive layer, wherein the transfer layer is hardened by irradiation with active energy rays. When the adhesive layer of the adhesive sheet is bonded to a glass plate, the adhesive force (I) is greater than 2 N/20 mm at 23°C. The adhesive force (I) of the adhesive layer of the adhesive sheet when bonded to the glass plate at 23°C relative to the adhesive force (B) of the transfer layer of the adhesive sheet to the stainless steel plate at 23°C after the transfer layer is bonded to the stainless steel plate and irradiated with ultraviolet rays at 300 mJ/ ^cm² is 5 or greater. The light transmittance of the adhesive sheet at a wavelength of 248 nm is less than 50%. The adhesive sheet of claim 1 further comprises a substrate between the adhesive layer and the transfer layer. The adhesive sheet of claim 1 or 2, wherein after irradiation with ultraviolet light at 300 mJ/ ^cm2 , the transfer layer has an indentation modulus (B) at 23°C that is at least five times the indentation modulus (I) of the adhesive layer at 23°C. The adhesive sheet according to claim 1 or 2, wherein the transfer layer contains an active energy ray-curable adhesive containing an acrylic polymer as a base polymer. The adhesive sheet of claim 1 or 2 can be used for the following purpose: using the adhesive sheet to temporarily fix a component on a support, and after transportation and/or processing, the component is peeled off from the support by laser light irradiation. The adhesive sheet of claim 3, wherein the transfer layer contains an active energy ray-curable adhesive containing an acrylic polymer as a base polymer.