Reutilization method of transport carrier

Abstract

To provide a reutilization method of a transport carrier with an adhesive sheet laminated, the reutilization method capable of preventing a transport carrier from breaking or from being polluted.SOLUTION: A reutilization method includes: a step A of disposing a transport-target object on a double-sided adhesive sheet-attached transport carrier including a transport carrier and a double-sided adhesive sheet arranged on one side of the transport carrier; a step B of separating the transport-target object from the double-sided adhesive sheet-attached transport carrier, the step including irradiating the double-sided adhesive sheet with active energy rays and thereafter with laser beams; and a step C of separating the double-sided adhesive sheet from the transport carrier. The double-sided adhesive sheet includes an active energy ray-curable adhesive layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for recycling a transport carrier. [Background technology]

[0002] Conventionally, when transferring electronic components, i.e., when transferring electronic components placed on a predetermined component to another component, the electronic components are received with an adhesive sheet and then transferred to the other component. For example, when incorporating LED chips into a device, the LED chips formed on the component are first transferred onto an adhesive sheet supported by a predetermined transport carrier, and then the LED chips are transferred from the adhesive sheet to the predetermined device or component.

[0003] Usually, the transport carrier is discarded after the transfer, but in a manufacturing method that requires an expensive transport carrier, the disposal of the transport carrier causes a cost increase problem. Furthermore, when the transport carrier is reused, problems arise such as contamination of the transport carrier after peeling off the adhesive sheet and damage to the transport carrier during cleaning. In recent years, laser light irradiation is sometimes used to induce releasability when transferring electronic components, and in such cases, expensive transport carriers that can transmit laser light are used, making the above problems more pronounced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5875850 [Patent Document 2] Patent No. 6053756 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to provide a method for recycling a transport carrier having an adhesive sheet laminated thereon, which can prevent damage and contamination of the transport carrier. [Means for solving the problem]

[0006] 1. A method for recycling a transport carrier according to an embodiment of the present invention includes: step A: placing an article to be transported on a transport carrier with a double-sided adhesive sheet, the transport carrier comprising a transport carrier and a double-sided adhesive sheet arranged on one side of the transport carrier; step B: peeling the article to be transported from the transport carrier with the double-sided adhesive sheet, the step B including irradiating the double-sided adhesive sheet with active energy rays and then with laser light; and step C: peeling the double-sided adhesive sheet from the transport carrier, the double-sided adhesive sheet comprising an active energy ray-curable adhesive layer. 2. In the method for recycling a transport carrier described in 1 above, the transport carrier may be laser-transparent. 3. In the method for reusing a transport carrier according to the above 1 or 2, the step A may be a step of receiving electronic components by a laser lift-off process. 4. The method for recycling a transport carrier according to any one of the above items 1 to 3, wherein the amount of active energy ray irradiation in step B is an integrated light amount of 100 mJ / cm 2 It may be more than that. 5. In the method for recycling a transport carrier according to any one of 1 to 4 above, in step C, the adhesive strength of the double-sided pressure-sensitive adhesive sheet to the transport carrier at 23° C. may be 0.15 N / 20 mm or less. 6. In the method for recycling a transport carrier described in any one of 1 to 5 above, the transported item may be a mini LED or a micro LED. 7. In the method for recycling a transport carrier described in any one of 1 to 6 above, the adhesive layer may be composed of an active energy ray-curable adhesive, and the active energy ray-curable adhesive may contain a polymer having an unsaturated double bond. 8. In the method for recycling a transport carrier according to any one of the above items 1 to 7, the thickness of the adhesive layer may be 50 μm or less. 9. In the method for recycling a transport carrier described in any one of 1 to 8 above, in step C, the double-sided adhesive sheet may be peeled off by attaching a tab to the double-sided adhesive sheet and peeling off the double-sided adhesive sheet integrated with the tab. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a method for recycling a transport carrier having a pressure-sensitive adhesive sheet laminated thereon, which method can prevent damage and contamination of the transport carrier. [Brief explanation of the drawings]

[0008] [Figure 1] 1(a) to 1(c) are schematic cross-sectional views of a transport carrier with a double-sided adhesive sheet used in one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] A. How to reuse transport carriers A method for recycling a transport carrier according to one embodiment of the present invention includes: A step A of placing an article to be transferred on a transport carrier with a double-sided adhesive sheet, the transport carrier having a transport carrier and a double-sided adhesive sheet disposed on one side of the transport carrier; a step B (a step of peeling off the transferred article) of peeling off the transferred article from the conveying carrier with the double-sided adhesive sheet, the step B including irradiating the double-sided adhesive sheet with active energy rays and then irradiating it with laser light; and step C of peeling the double-sided adhesive sheet from the transport carrier (step of peeling the double-sided adhesive sheet).

[0010] A-1. Process A In one embodiment, the transport carrier has laser light transparency. In one embodiment, a transport carrier having a transmittance of 90% to 100% (preferably 95% to 100%) for laser light with a wavelength of 355 nm is used.

[0011] Any suitable carrier can be used as long as the effects of the present invention can be obtained. The carrier may be made of, for example, glass, quartz glass, or the like. Preferably, a glass carrier is used. The thickness of the carrier is, for example, 0.5 mm to 2 mm.

[0012] The transported article is typically an electronic component, such as a mini LED or a micro LED.

[0013] In one embodiment, step A may be a step of receiving electronic components by a laser lift-off process. In the above embodiment, step A may include transferring and arranging a plurality of items to be transferred (e.g., electronic components such as LED chips) arranged on a substrate (e.g., a hard substrate such as a sapphire substrate) onto a double-sided adhesive sheet. The laser lift-off process includes irradiating an adhesive layer with laser light to reduce the adhesive strength of the adhesive layer and promote peeling of the adherend. Step A and step B may constitute a laser lift-off process.

[0014] The double-sided adhesive sheet includes an active energy ray-curable adhesive layer. The transported article can be placed on the adhesive layer. The double-sided adhesive sheet-equipped transport carrier can be configured by adhering the adhesive layer to the transport carrier. FIG. 1 is a schematic cross-sectional view of a double-sided adhesive sheet-equipped transport carrier used in one embodiment of the present invention. FIG. 1 shows double-sided adhesive sheet-equipped transport carriers 100, 100', and 100'' each including a double-sided adhesive sheet 10 and a transport carrier 20. In one embodiment, the double-sided adhesive sheet 10 constituting the double-sided adhesive sheet-equipped transport carrier 100 includes a single adhesive layer 1 having a monolayer structure, as shown in FIG. 1(a). In another embodiment, the double-sided adhesive sheet includes two or more adhesive layers 1, 1', as shown in FIGS. 1(b) and 1(c). The two or more adhesive layers may have the same composition or different compositions. Furthermore, as shown in FIG. 1(c), the double-sided adhesive sheet may include a substrate 2 between the adhesive layers 1, 1'. The double-sided PSA sheet may further include any other appropriate layer as long as the effects of the present invention are obtained.

[0015] In the present invention, a double-sided pressure-sensitive adhesive sheet having an active energy ray-curable adhesive layer is used, and by undergoing step B (a step of peeling the transferred article) which involves irradiating the double-sided pressure-sensitive adhesive sheet with active energy rays to make the double-sided pressure-sensitive adhesive sheet easy to peel, the double-sided pressure-sensitive adhesive sheet can be preferably peeled from the transfer carrier. According to the present invention, damage to the transfer carrier when peeling the double-sided pressure-sensitive adhesive sheet is prevented. Furthermore, adhesive residue is prevented, and a clean transfer carrier can be obtained, making the transfer carrier reusable. The transfer carrier obtained by the above method is free of contamination and smooth, so that the transferred article can be positioned with high positional accuracy even when reused. Examples of active energy rays include gamma rays, ultraviolet rays, visible light, infrared rays (heat rays), radio waves, alpha rays, beta rays, electron beams, plasma flow, ionizing rays, and particle beams. Ultraviolet rays are preferred.

[0016] In one embodiment, the pressure-sensitive adhesive layer is configured to be capable of absorbing active energy rays. Forming a pressure-sensitive adhesive layer configured in this manner allows for favorable release properties upon irradiation with laser light in step B. In one embodiment, the pressure-sensitive adhesive layer contains an ultraviolet absorber and / or a photopolymerization initiator, enabling release of an adherend (electronic component) upon irradiation with laser light. More specifically, irradiating the pressure-sensitive adhesive layer with laser light heats the ultraviolet absorber or photopolymerization initiator, causing strain in the pressure-sensitive adhesive layer, resulting in release properties in the area irradiated with the laser light. According to this embodiment, strain can be generated in the pressure-sensitive adhesive layer over a small area, allowing for favorable release of small electronic components (e.g., 50 μm square) even when the electronic component is processed.

[0017] The double-sided pressure-sensitive adhesive sheet has a light transmittance at a wavelength of 355 nm of, for example, 70% or less, preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less. Within this range, the laser output during peeling in step B can be reduced. The light transmittance of the double-sided pressure-sensitive adhesive sheet refers to the light transmittance in the thickness direction of the double-sided pressure-sensitive adhesive sheet, and is the light transmittance measured for all of the constituent layers of the double-sided pressure-sensitive adhesive sheet. The light transmittance at a wavelength of 355 nm of the double-sided pressure-sensitive adhesive sheet can be controlled, for example, by adjusting the content of the ultraviolet absorber in the pressure-sensitive adhesive layer. The light transmittance at a wavelength of 355 nm of the double-sided pressure-sensitive adhesive sheet can also be controlled by the composition of the base polymer and photopolymerization initiator that constitute the pressure-sensitive adhesive layer. For example, the light transmittance at a wavelength of 355 nm of the double-sided pressure-sensitive adhesive sheet can be controlled by the type and amount of the photopolymerization initiator contained in the pressure-sensitive adhesive layer, particularly the compatibility between the photopolymerization initiator and the base polymer.

[0018] The visible light transmittance of the double-sided pressure-sensitive adhesive sheet is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. Within this range, a double-sided pressure-sensitive adhesive sheet can be obtained that allows the adherend to be easily visible through the double-sided pressure-sensitive adhesive sheet when the adherend is peeled off by laser light irradiation. The higher the visible light transmittance of the double-sided pressure-sensitive adhesive sheet, the better, but the upper limit is, for example, 95% (preferably 100%).

[0019] The haze value of the double-sided pressure-sensitive adhesive sheet is preferably 70% or less, more preferably 65% ​​or less. Within this range, a double-sided pressure-sensitive adhesive sheet can be obtained that allows the adherend to be easily visible through the double-sided pressure-sensitive adhesive sheet when the adherend is peeled off by laser light irradiation. The lower the haze value of the double-sided pressure-sensitive adhesive sheet, the better, and the lower limit is, for example, 0.1%.

[0020] The initial adhesive strength A1 of the double-sided PSA sheet at 23°C to a stainless steel plate on the side where the transferred product is placed is preferably 0.1 N / 20 mm to 15 N / 20 mm, more preferably 0.5 N / 20 mm to 10 N / 20 mm. Within these ranges, a double-sided PSA sheet capable of holding the transferred product well can be obtained. The adhesive strength is measured in accordance with JIS Z 0237:2000. Specifically, the double-sided PSA sheet is adhered to a stainless steel plate (arithmetic mean surface roughness Ra: 50±25 nm) using a 2 kg roller in one reciprocating motion, left at 23°C for 30 minutes, and then peeled off at a peel angle of 180° and a peel rate (pulling speed) of 300 mm / min. The adhesive strength of the PSA layer changes upon irradiation with active energy rays and laser light. In this specification, "initial adhesive strength" refers to the adhesive strength before irradiation with active energy rays and laser light.

[0021] The initial adhesive strength A2 of the double-sided pressure-sensitive adhesive sheet at 23° C. to the stainless steel plate on the side where the transport carrier is placed is preferably 0.1 N / 20 mm to 15 N / 20 mm, and more preferably 0.5 N / 20 mm to 10 N / 20 mm.

[0022] In one embodiment, the side of the double-sided pressure-sensitive adhesive sheet on which the transferred article is placed is attached to a stainless steel plate, and 300 mJ / cm 2 The adhesive strength B1 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 even more preferably 0.02 N / 20 mm to 0.15 N / 20 mm. Within these ranges, a double-sided PSA sheet can be obtained that leaves little adhesive residue on the transported article. The ultraviolet light irradiation can be carried out, for example, using an ultraviolet light irradiation device (manufactured by Nitto Seiki Co., Ltd., product name "UM-810"), using ultraviolet light from a high-pressure mercury lamp (characteristic wavelength: 365 nm, cumulative light intensity: 300 mJ / cm). 2 ) is irradiated onto the adhesive layer.

[0023] In one embodiment, the side of the double-sided adhesive sheet on which the transport carrier is placed is attached to a stainless steel plate, and 300 mJ / cm 2 The adhesive strength B2 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 even more preferably 0.02 N / 20 mm to 0.15 N / 20 mm. Within these ranges, a double-sided PSA sheet with little adhesive residue on the transport carrier can be obtained. The ultraviolet light irradiation can be carried out, for example, using an ultraviolet light irradiation device (manufactured by Nitto Seiki Co., Ltd., product name "UM-810"), using ultraviolet light from a high-pressure mercury lamp (characteristic wavelength: 365 nm, integrated light amount: 300 mJ / cm). 2 ) is irradiated onto the adhesive layer.

[0024] The double-sided pressure-sensitive adhesive sheet preferably has a thickness of 1 μm to 300 μm, and more preferably 5 μm to 200 μm.In one embodiment, the double-sided pressure-sensitive adhesive sheet has a thickness of 60 μm or less.

[0025] The thickness of the pressure-sensitive adhesive layer is preferably 50 μm or less, more preferably 5 μm to 50 μm, and even more preferably 10 μm to 40 μm.

[0026] The pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, which includes a base polymer, and may further include the ultraviolet absorber and / or photopolymerization initiator.

[0027] (Active energy ray curable adhesive) In one embodiment, an active energy ray-curable adhesive (A1) is used as the active energy ray-curable adhesive, which comprises 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-curable adhesive (A2) is used, which comprises an active energy ray-reactive polymer as the base polymer. Preferably, the base polymer has a functional group capable of reacting with a photopolymerization initiator. Examples of such functional groups include a hydroxyl group and a carboxyl group.

[0028] Examples of base polymers used in the PSA (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-based polymers. These polymers may be used alone or in combination of two or more. Among these, acrylic polymers are preferred.

[0029] Examples of acrylic polymers include homopolymers or copolymers of hydrocarbon group-containing (meth)acrylic acid esters, such as (meth)acrylic acid alkyl esters, (meth)acrylic acid cycloalkyl esters, and (meth)acrylic acid aryl esters; and copolymers of such hydrocarbon group-containing (meth)acrylic acid esters with other copolymerizable monomers. Examples of (meth)acrylic acid alkyl esters include the methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester (i.e., lauryl ester), tridecyl ester, tetradecyl ester, hexadecyl ester, octadecyl ester, and eicosyl ester of (meth)acrylic acid. Examples of (meth)acrylic acid cycloalkyl esters include the cyclopentyl ester and cyclohexyl ester of (meth)acrylic acid. Examples of (meth)acrylic acid aryl esters include phenyl (meth)acrylate and benzyl (meth)acrylate. The content of the structural unit derived from the hydrocarbon group-containing (meth)acrylic acid ester is preferably 40 parts by weight or more, more preferably 60 parts by weight or more, per 100 parts by weight of the base polymer.

[0030] Examples of the other copolymerizable monomers include functional group-containing monomers such as 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 acrylonitrile. Examples of the 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 the acid anhydride monomers include maleic anhydride and itaconic anhydride. Examples of the 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 styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of phosphate group-containing monomers include 2-hydroxyethyl acryloyl phosphate. Examples of acrylamides include N-acryloylmorpholine. These 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, more preferably 40 parts by weight or less, per 100 parts by weight of the base polymer.

[0031] The acrylic polymer may contain structural units derived from polyfunctional monomers to form crosslinked structures in the 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 alone or in combination of two or more. The content of the structural units derived from the polyfunctional monomer is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, per 100 parts by weight of the base polymer.

[0032] The weight-average molecular weight of the 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).

[0033] Examples of the active energy ray reactive compound that can be used in the pressure-sensitive adhesive (A1) include photoreactive monomers or oligomers having a functional group with a polymerizable carbon-carbon multiple bond, 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 and 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, and polyethylene glycol di(meth)acrylate; polyfunctional urethane (meth)acrylate; epoxy (meth)acrylate; oligoester (meth)acrylate; etc. Also usable are monomers such as methacryloisocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), and m-isopropenyl-α,α-dimethylbenzyl isocyanate. Specific examples of the photoreactive oligomer include dimers to pentamers of the above-mentioned monomers. The molecular weight of the photoreactive oligomer is preferably 100 to 3,000.

[0034] In one embodiment, the active energy ray reactive compound is a polyfunctional (meth)acrylate having five or more functional groups, or an oligomer of a polyfunctional (meth)acrylate having five or more functional groups. By using such an active energy ray reactive compound, it is possible to form a pressure-sensitive adhesive layer that can become highly elastic when irradiated with active energy rays (e.g., ultraviolet rays). If the pressure-sensitive adhesive layer can be made to have a high elastic modulus, the above-mentioned peeling operation can be performed using a low-power laser beam.

[0035] Furthermore, as the active energy ray reactive compound, a monomer such as epoxidized butadiene, glycidyl methacrylate, acrylamide, vinyl siloxane, or the like, or an oligomer composed of such a monomer may be used.

[0036] Furthermore, the active energy ray-reactive compound may be a mixture of an organic salt such as an onium salt and a compound having multiple heterocycles in the molecule. When the mixture is irradiated with active energy rays (e.g., ultraviolet light or an electron beam), the organic salt is cleaved to generate ions, which act as initiating species to cause a ring-opening reaction of the heterocycles, forming a three-dimensional network structure. Examples of the organic salt include iodonium salts, phosphonium salts, antimonium salts, sulfonium salts, and borate salts. Examples of the heterocycle in the compound having multiple heterocycles in the molecule include oxirane, oxetane, oxolane, thiirane, and aziridine.

[0037] In the pressure-sensitive adhesive (A1), the content 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, relative to 100 parts by weight of the base polymer.

[0038] Examples of the active energy ray-reactive polymer (base polymer) contained in the pressure-sensitive adhesive (A2) include polymers having functional groups with carbon-carbon multiple bonds such as acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, acetylene groups, etc. Specific examples of the active energy ray-reactive polymer include polymers composed of multifunctional (meth)acrylates, photocationic polymerizable polymers, cinnamoyl group-containing polymers such as polyvinyl cinnamate, diazotized amino novolac resins, polyacrylamides, etc.

[0039] In one embodiment, the active energy ray-curable pressure-sensitive adhesive comprises a base polymer having an active energy ray-polymerizable carbon-carbon multiple bond (e.g., an unsaturated double bond). Examples of such polymers include active energy ray-reactive polymers obtained by introducing active energy ray-polymerizable carbon-carbon multiple bonds (e.g., unsaturated double bonds) into the side chains, main chain, and / or main chain terminals of the acrylic polymer (precursor resin). Examples of methods for introducing radiation-polymerizable carbon-carbon double bonds into the acrylic polymer (precursor resin) include copolymerizing raw material monomers including a monomer having a predetermined functional group (first functional group) to obtain the acrylic polymer (precursor resin), and then subjecting a compound having a radiation-polymerizable carbon-carbon double bond and a predetermined functional group (second functional group) capable of reacting with and bonding to the first functional group (hereinafter simply referred to as a compound having a carbon double bond) to a condensation reaction or addition reaction with the acrylic polymer while maintaining the radiation polymerizability of the carbon-carbon double bond.

[0040] The amount of the compound having a carbon-carbon double bond introduced is preferably 10 parts by weight or more, more preferably 12 parts by weight or more, and even more preferably 15 parts by weight or more, relative to 100 parts by weight of the solid content of the acrylic polymer (precursor resin). Within this range, a low-polarity active energy ray-reactive polymer (base polymer) can be obtained. By using this base polymer, even if the adhesive layer has a relatively low elastic modulus after ultraviolet irradiation, adherend peeling can be preferably performed by low-energy laser light irradiation. The upper limit of the amount of the compound having a carbon-carbon double bond introduced is, for example, 80 parts by weight (preferably 60 parts by weight, more preferably 50 parts by weight) relative to 100 parts by weight of the solid content of the acrylic polymer (precursor resin).

[0041] 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 aziridyl group, an aziridyl group and a carboxyl group, a hydroxyl group and an isocyanate group, and an isocyanate group and a hydroxyl group. Among these combinations, a hydroxyl group and an isocyanate group, or an isocyanate group and a hydroxyl group, is preferred from the viewpoint of ease of reaction tracking. Furthermore, while producing a polymer having a highly reactive isocyanate group is technically difficult, from the viewpoint of ease of production or availability of the acrylic polymer, it is more preferred that the first functional group on the acrylic polymer be a hydroxyl group and the second functional group 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 the 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 is preferably one that contains a structural unit derived from the above-mentioned hydroxy group-containing monomer, and is also preferably one that contains a structural unit derived from an ether compound such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, or diethylene glycol monovinyl ether.

[0042] The pressure-sensitive adhesive (A2) may further contain the active energy ray-reactive compound (monomer or oligomer).

[0043] (ultraviolet absorber) Any appropriate ultraviolet absorber can be used as the ultraviolet absorber, as long as it is a compound that absorbs ultraviolet light (for example, a wavelength of 355 nm). Examples of ultraviolet absorbers include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, triazine-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers. Among these, triazine-based ultraviolet absorbers or benzotriazole-based ultraviolet absorbers are preferred, and triazine-based ultraviolet absorbers are particularly preferred. In particular, when an acrylic adhesive is used as the adhesive, triazine-based ultraviolet absorbers can be preferably used because of their high compatibility with the base polymer of the acrylic adhesive. The triazine-based ultraviolet absorber is more preferably composed of a compound having a hydroxyl group, and is particularly preferably an ultraviolet absorber composed of a hydroxyphenyltriazine-based compound (hydroxyphenyltriazine-based ultraviolet absorber).

[0044] Examples of hydroxyphenyltriazine-based ultraviolet absorbers include a reaction product of 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-hydroxyphenyl with [(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-triazin-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol), a reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine with (2-ethylhexyl)-glycidic acid ester (trade name "TINUVIN 405, manufactured by BASF), 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (trade name "TINUVIN 460", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol (trade name "TINUVIN 1577", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (trade 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 (trade name "TINUVIN BASF's trade name "TINUVIN 477" and the like.

[0045] Examples of benzotriazole-based ultraviolet absorbers (benzotriazole-based compounds) include 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (trade name "TINUVIN PS", manufactured by BASF), an ester compound of benzenepropanoic acid and 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy (C7-9 side chain and linear alkyl) (trade name "TINUVIN 384-2", manufactured by BASF), a mixture of octyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate (trade name "TINUVIN 109, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN 900", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN 928", manufactured by BASF), reaction products of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 (trade name "TINUVIN 1130", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-p-cresol (trade 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 products of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate with 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-tetrahydrophthalimido-methyl)-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 (trade name "SEESORB 703" manufactured by Shipro Chemical Co., Ltd.), 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimidylmethyl)phenol (trade name "SEESORB 706" manufactured by Shipro Chemical Co., Ltd.), 2-(4-benzoyloxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole (trade name "SEESORB 7012BA" manufactured by Shipro Chemical Co., Ltd.), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (trade name "KEMISORB 73" manufactured by Chemipro Chemical Co., Ltd.), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] (trade name "ADK STAB LA-31" manufactured by ADEKA Corporation), 2-(2H-benzotriazol-2-yl)-p-cellulose (trade name "ADK STAB LA-32" manufactured by ADEKA Corporation), 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol (trade name "ADK STAB LA-36" manufactured by ADEKA Corporation), etc.

[0046] The ultraviolet absorber may be a dye or a pigment. Examples of pigments include azo-based, phthalocyanine-based, anthraquinone-based, lake-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxandine-based, isoindolinone-based, and quinophthalone-based pigments. Examples of dyes include azo-based, phthalocyanine-based, anthraquinone-based, carbonyl-based, indigo-based, quinoneimine-based, methine-based, quinoline-based, and nitro-based dyes.

[0047] The molecular weight of the compound constituting the ultraviolet absorber is preferably 1000 or less, more preferably 800 or less, and even more preferably 600 or less. Because ultraviolet absorbers having a molecular weight within the above range have excellent compatibility with base polymers, when such ultraviolet absorbers are used, distortion occurs only at the laser-irradiated area upon laser light irradiation, making it possible to achieve peeling with very low laser energy. As a result, thermal decomposition of the pressure-sensitive adhesive layer can be prevented. By forming such a pressure-sensitive adhesive layer, a double-sided pressure-sensitive adhesive sheet that is less likely to contaminate the adherend can be obtained. The lower limit of the molecular weight of the compound constituting the ultraviolet absorber is, for example, 100.

[0048] The maximum absorption wavelength of the 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. The difference between the maximum absorption wavelength of the ultraviolet absorber and the maximum absorption wavelength of the photopolymerization initiator is preferably 10 nm or more, more preferably 25 nm or more.

[0049] The content of the ultraviolet absorber 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, relative to 100 parts by weight of the base polymer in the pressure-sensitive adhesive layer. Within this range, when the adhesive strength of the entire pressure-sensitive adhesive layer is favorably reduced by irradiation with active energy rays, the pressure-sensitive adhesive layer is favorably cured, and a double-sided pressure-sensitive adhesive sheet that exhibits favorable releasability by irradiation with laser light can be obtained.

[0050] (Photopolymerization initiator) Any suitable initiator can be used as the photopolymerization initiator. Examples of the photopolymerization initiator 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 benzyl dimethyl ketal. Examples of suitable photopolymerization initiators 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 the photopolymerization initiator used can be set to any appropriate amount.

[0051] In one embodiment, the photopolymerization initiator used has two or more (preferably 2 to 5) photodegradable groups. Use of such a photopolymerization initiator makes it possible to form a pressure-sensitive adhesive layer that can become highly elastic upon irradiation with active energy rays (e.g., ultraviolet rays). If the pressure-sensitive adhesive layer can be made to have a high elastic modulus, the peeling operation can be performed using a low-power laser beam. The photodegradable group refers to a functional group that absorbs irradiated active energy rays and generates radicals, and specific examples thereof include a ketone group, a halogenated alkyl group, an ester group, a sulfone group, and a peroxy group.

[0052] 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-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one (trade name ESURE1001M), methyl benzoyl formate (trade name SPEEDCURE MBF, manufactured by LAMBSON), O-ethoxyimino-1-phenylpropan-1-one (trade name SPEEDCURE PDO, manufactured by LAMBSON), and oligo[2-hydroxy-2-methyl-4-(1-methylvinyl)phenyl]propanone (trade name ESCURE KIPI50, manufactured by LAMBERTI).

[0053] 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'-morpholinobutyrophenone (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), 1,2-octanedione-1-[4-(phenylthio)phenyl-2-(O-benzoyloxime)] (trade name Omnirad379, manufactured by BASF Japan), and 1,2-octanedione-1-[4-(phenylthio)phenyl-2-(O-benzoyloxime)] (trade name Omnirad379, manufactured by BASF Japan). Examples of such photopolymerization initiators include OmniradOXE01 (manufactured by BASF Japan), ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (trade name OmniradOXE02, manufactured by BASF Japan), etc. The use of such photopolymerization initiators makes it possible to form a pressure-sensitive adhesive layer that can become highly elastic when irradiated with active energy rays (e.g., ultraviolet rays). If the pressure-sensitive adhesive layer can be made to have a high elastic modulus, the above-mentioned peeling operation can be performed using a low-power laser beam.

[0054] The content of the 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, relative to 100 parts by weight of the base polymer in the pressure-sensitive adhesive layer. Within this range, when the adhesive strength of the entire pressure-sensitive adhesive layer is satisfactorily reduced by irradiation with active energy rays, the pressure-sensitive adhesive layer undergoes good curing, and the amount of distortion of the pressure-sensitive adhesive layer due to laser light irradiation is large, making it possible to obtain a double-sided pressure-sensitive adhesive sheet that exhibits good releasability.

[0055] In one embodiment, the active energy ray-curable pressure-sensitive adhesive may contain a photosensitizer.

[0056] In one embodiment, the photosensitizer can be used in combination with the photopolymerization initiator. The photosensitizer can transfer the energy it obtains by absorbing light to the photopolymerization initiator, thereby generating radicals from the photopolymerization initiator. This allows polymerization to proceed with light on the long wavelength side, where the photopolymerization initiator itself does not have an absorption peak. Therefore, by incorporating a photosensitizer, it is possible to increase the difference between the absorption wavelength of the UV absorber and the wavelength at which radicals can be generated from the photopolymerization initiator. As a result, photopolymerization of the pressure-sensitive adhesive layer and peeling by the UV absorber can be performed without affecting each other. In one embodiment, 2,2-dimethoxy-1,2-diphenylethan-1-one (e.g., BASF, trade name "Irgacure 651") as a photopolymerization initiator and a photosensitizer are used in combination. Examples of such photosensitizers include "UVS-581" (trade name, manufactured by Kawasaki Chemical Industries, Ltd.), and 9,10-diethoxyanthracene (for example, "UVS1101" (trade name, manufactured by Kawasaki Chemical Industries, Ltd.)).

[0057] Other examples of the photosensitizer include 9,10-dibutoxyanthracene (e.g., Kawasaki Chemical Industries, Ltd., trade name "UVS-1331"), 2-isopropylthioxanthone, benzophenone, thioxanthone derivatives, 4,4'-bis(dimethylamino)benzophenone, etc. Examples of thioxanthone derivatives include ethoxycarbonylthioxanthone, isopropylthioxanthone, etc.

[0058] The content of the 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.

[0059] Preferably, the active energy ray-curable pressure-sensitive adhesive contains a crosslinking agent, such as an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a melamine-based crosslinking agent, a peroxide-based crosslinking agent, a urea-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, a metal salt-based crosslinking agent, a carbodiimide-based crosslinking agent, or an amine-based crosslinking agent.

[0060] The content of the crosslinking agent is preferably 0.5 to 10 parts by weight, and more preferably 1 to 8 parts by weight, relative to 100 parts by weight of the base polymer of the pressure-sensitive adhesive.

[0061] In one embodiment, an isocyanate-based crosslinking agent is preferably used, which is preferred because it can react with a variety of functional groups. Specific examples of the isocyanate-based crosslinking agent 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; and 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 of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HX"). Preferably, a crosslinking agent having three or more isocyanate groups is used.

[0062] The active energy ray-curable pressure-sensitive adhesive may further contain any appropriate additives as necessary, such as an active energy ray polymerization accelerator, a radical scavenger, a tackifier, a plasticizer (e.g., a trimellitic acid ester-based plasticizer, a pyromellitic acid ester-based plasticizer, etc.), a pigment, a dye, a filler, an antioxidant, a conductive material, an antistatic agent, an ultraviolet absorber, a light stabilizer, a release adjuster, a softener, a surfactant, a flame retardant, and an antioxidant.

[0063] The substrate may be made of any appropriate resin. Examples of the resin include polyolefin resins such as polyethylene resins, polypropylene resins, polybutene resins, and polymethylpentene resins, polyurethane resins, polyester resins, polyimide resins, polyether ketone resins, polystyrene resins, polyvinyl chloride resins, polyvinylidene chloride resins, fluorine resins, silicone resins, cellulose resins, and ionomer resins. Polyolefin resins are particularly preferred. 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. 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%).

[0064] A-2. Process B Step B, which follows step A, may involve peeling the object to be transferred from the double-sided pressure-sensitive adhesive sheet-attached transport carrier, and may include irradiating the double-sided pressure-sensitive adhesive sheet with active energy rays and then irradiating it with laser light. In one embodiment, step B includes (i) irradiating the double-sided pressure-sensitive adhesive sheet with active energy rays (e.g., ultraviolet light) to reduce the adhesive strength of the adhesive layer of the double-sided pressure-sensitive adhesive sheet, and (ii) irradiating the desired area for release with laser light to cause distortion in the adhesive layer and further reduce the adhesive strength. This method allows the object to be released only at the area irradiated with laser light. Use of the double-sided pressure-sensitive adhesive sheet can reduce the adhesive strength to the point where the object falls off naturally, making it possible to individually peel even very small electronic components (e.g., 50 μm square). In one embodiment, step B may be an electronic component peeling (transfer) step in a laser lift-off process.

[0065] The active energy rays in (i) above can be irradiated onto the entire surface of the pressure-sensitive adhesive layer. In one embodiment, the active energy rays have an integrated light dose of 100 mJ / cm. 2 The active energy ray (preferably ultraviolet light) is irradiated at a dose of 200 mJ / cm or more. Within this range, the peeling operation can be carried out with good workability. Furthermore, adhesive residue can be prevented after the double-sided PSA sheet is peeled in step C. The irradiation dose of the active energy ray (preferably ultraviolet light) is 200 mJ / cm or more. 2 Higher than 1500mJ / cm 2 may be less than 200 mJ / cm 2 ~1500mJ / cm 2 may be 300 mJ / cm 2 ~800mJ / cm 2 may be.

[0066] The laser light in (ii) has a wavelength of, for example, 200 nm to 360 nm (preferably 355 nm). The laser light output is, for example, 100 mJ / cm. 2 ~1200mJ / cm 2 is.

[0067] A-3.Process C Step C includes peeling off the double-sided adhesive sheet from the transport carrier after step B. This step separates the transport carrier into individual units, allowing the transport carrier to be reused.

[0068] In step C, the adhesive strength of the double-sided pressure-sensitive adhesive sheet to the transport carrier at 23°C is 0.15 N / 20 mm or less, more preferably 0.13 N / 20 mm or less, even more preferably 0.1 N / 20 mm or less, and particularly preferably 0.08 N / 20 mm or less. Within these ranges, the effects of the present invention are remarkable. Furthermore, in step C, the adhesive strength of the double-sided pressure-sensitive adhesive sheet to the transport carrier at 23°C is preferably 0.02 N / 20 mm or more.

[0069] In one embodiment, a tab is attached to the double-sided pressure-sensitive adhesive sheet, and the double-sided pressure-sensitive adhesive sheet is peeled off by pulling off the double-sided pressure-sensitive adhesive sheet integrated with the tab. A portion of the tab is attached to the double-sided pressure-sensitive adhesive sheet, and the portion that is not attached serves as a gripping margin. The use of the tab improves ease of peeling and contamination resistance.

[0070] Any suitable tab can be used as the tab as long as it has a predetermined adhesive strength to the double-sided adhesive sheet. For example, any suitable adhesive tape can be used.

[0071] The adhesive strength of the tab to the double-sided adhesive sheet at 23°C is preferably higher than the adhesive strength of the double-sided adhesive sheet to the transport carrier at 23°C. [Example]

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Test and evaluation methods in the examples are as follows. Unless otherwise specified, "parts" and "%" are by weight.

[0073] [Production Example 1] Preparation of acrylic polymer A A monomer composition was prepared by mixing 65 parts by weight of isononyl acrylate, 25 parts by weight of 2-hydroxyethyl acrylate, and 10 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, a thermometer, and a stirrer, and under a nitrogen atmosphere, 200 parts by weight of ethyl acetate, 100 parts by weight of the monomer composition, and 0.2 parts by weight of AIBN were charged and stirred for 5 hours at 63° C. Thereafter, the mixture was cooled to room temperature, and 31 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 the 2-hydroxyethyl acrylate in the copolymer, thereby obtaining an acrylic polymer solution A containing an acrylic polymer A having a terminal carbon-carbon double bond and to which an ultraviolet absorber was bound.

[0074] [Production 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, a thermometer, and a stirrer, and under a nitrogen atmosphere, 280 parts by weight of ethyl acetate, 132 parts by weight of the monomer composition, and 0.3 parts by weight of AIBN were charged and stirred for 4 hours at 60° C. Thereafter, the mixture was cooled to room temperature, and 29 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 the 2-hydroxyethyl acrylate in the copolymer, yielding acrylic polymer solution B containing acrylic polymer B having a terminal carbon-carbon double bond.

[0075] [Production Example 3] Preparation of Acrylic Polymer C A monomer composition was prepared by mixing 100 parts by weight of 2-ethylhexyl acrylate, 26 parts by weight of acryloylmorpholine, and 19 parts by weight of 2-hydroxyethyl acrylate. Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer, and under a nitrogen atmosphere, 400 parts by weight of ethyl acetate, 132 parts by weight of the monomer composition, and 0.4 parts by weight of benzoyl peroxide (BPO) were charged and stirred for 4 hours at 60° C. Thereafter, the mixture was cooled to room temperature, and 21 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 the 2-hydroxyethyl acrylate in the copolymer, thereby obtaining an acrylic polymer solution C containing an acrylic polymer C having a terminal carbon-carbon double bond.

[0076] [Production Example 4] Preparation of Acrylic Polymer D A monomer composition was prepared by mixing 75 parts by weight of 2-ethylhexyl acrylate and 25 parts by weight of acryloylmorpholine. Next, nitrogen was introduced into a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer, and under a nitrogen atmosphere, 300 parts by weight of ethyl acetate, 100 parts by weight of the monomer composition, and 0.2 parts by weight of AIBN were charged and stirred for 4 hours at 60° C. Thereafter, the mixture was cooled to room temperature to obtain an acrylic polymer solution D containing an acrylic polymer D.

[0077] [Example 1] To an acrylic polymer solution A containing 100 parts by weight of acrylic polymer A, 1 part by weight of a crosslinking agent (manufactured by Mitsui Chemicals, Inc., 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 active energy ray-curable adhesive (1a). To an acrylic polymer solution B containing 100 parts by weight of acrylic polymer B, 1 part by weight of a crosslinking agent (manufactured by Mitsui Chemicals, Inc., 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 active energy ray-curable adhesive (2b). The above-mentioned adhesive (1a) was applied to the silicone-treated surface of a release liner (Diafoil MRF38 (thickness: 38 μm) manufactured by Mitsubishi Chemical Corporation), and then heated at 130°C for 2 minutes to form a first adhesive layer with a thickness of 5 μm. Separately, the above-mentioned adhesive (2b) was applied to the silicone-treated surface of a release liner (Diafoil MRE38 (thickness: 38 μm) manufactured by Mitsubishi Chemical Corporation), and then heated at 130°C for 2 minutes to form a second adhesive layer with a thickness of 5 μm. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer were bonded together to obtain a pressure-sensitive adhesive sheet with a release liner (release liner / first pressure-sensitive adhesive layer / second pressure-sensitive adhesive layer / release liner). (Glass peeling force) The release liner (Diafoil MRE38, manufactured by Mitsubishi Chemical Corporation) on the side of the first adhesive layer was peeled off, and the first adhesive layer was attached to a glass slide (manufactured by Matsunami Glass, product name "S9111") using a hand roller. The release liner (Diafoil MRF38, manufactured by Mitsubishi Chemical Corporation) on the other side was then peeled off, and a tab (No. 315, manufactured by Nitto Denko Corporation) was attached to the adhesive surface of the second adhesive layer. Then, using an ultraviolet irradiation device (manufactured by Nitto Seiki, product name "UM-810"), the entire surface of the adhesive sheet was irradiated with a predetermined amount of ultraviolet light from a high-pressure mercury lamp from the glass slide side. The adhesive sheet was then peeled from the glass slide at a peel angle of 180°, a peel speed of 300 mm / min, and a sample width of 20 mm, and the peel strength against glass (N / 20 mm) was determined. The ultraviolet irradiation dose was 100 mJ / cm. 2 , 200mJ / cm 2 , 500mJ / cm 2 and 1000 mJ / cm 2 The peel strength to glass was measured. The results are shown in Table 1. When the glass peeling resistance is 0.06 N / 20 mm or more and less than 0.14 N / 20 mm, the reusability of the transport carrier in the above process is particularly excellent (◯ in the table).

[0078] [Example 2] Except for changing the thickness of the second pressure-sensitive adhesive layer to 45 μm, a pressure-sensitive adhesive sheet with a release liner (release liner / first pressure-sensitive adhesive layer / second pressure-sensitive adhesive layer / release liner) was obtained in the same manner as in Example 1. The obtained pressure-sensitive adhesive sheet was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

[0079] [Example 3] To an acrylic polymer solution A containing 100 parts by weight of acrylic polymer A, 1 part by weight of a crosslinking agent (manufactured by Mitsui Chemicals, Inc., 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 active energy ray-curable adhesive (1a). To an acrylic polymer solution B containing 100 parts by weight of acrylic polymer C, 5 parts by weight of a crosslinking agent (manufactured by Mitsui Chemicals, Inc., 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 active energy ray-curable adhesive (2c). The above-mentioned adhesive (1a) was applied to the silicone-treated surface of a release liner (Diafoil MRF38 (thickness: 38 μm) manufactured by Mitsubishi Chemical Corporation), and then heated at 130°C for 2 minutes to form a first adhesive layer with a thickness of 5 μm. Separately, the above-mentioned adhesive (2c) was applied to the silicone-treated surface of a release liner (Diafoil MRE38 (thickness: 38 μm) manufactured by Mitsubishi Chemical Corporation), and then heated at 130°C for 2 minutes to form a second adhesive layer with a thickness of 5 μm. The first and second pressure-sensitive adhesive layers were bonded together to obtain a pressure-sensitive adhesive sheet with a release liner (release liner / first pressure-sensitive adhesive layer / second pressure-sensitive adhesive layer / release liner). The resulting pressure-sensitive adhesive sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0080] [Example 4] Except for changing the thickness of the second pressure-sensitive adhesive layer to 45 μm, a pressure-sensitive adhesive sheet with a release liner (release liner / first pressure-sensitive adhesive layer / second pressure-sensitive adhesive layer / release liner) was obtained in the same manner as in Example 3. The obtained pressure-sensitive adhesive sheet was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

[0081] [Comparative Example 1] To an acrylic polymer solution D containing 100 parts by weight of acrylic polymer D, 2 parts by weight of a crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101A") and 2 parts by weight of Tetrad C were added to obtain a pressure-sensitive adhesive (1d). The above-mentioned adhesive (1d) was applied to the silicone-treated surface of a release liner (Diafoil MRF38 (thickness: 38 μm) manufactured by Mitsubishi Chemical Corporation), and then heated at 130°C for 2 minutes to form a first adhesive layer with a thickness of 10 μm, thereby obtaining an adhesive sheet with a release liner (release liner / first adhesive layer). (Glass peeling force) The release liner (Diafoil MRE38, manufactured by Mitsubishi Chemical Corporation) on the first adhesive layer side was peeled off, and the first adhesive layer side was attached to a slide glass (manufactured by Matsunami Glass, product name "S9111") using a hand roller. Then, the release liner (Diafoil MRF38, manufactured by Mitsubishi Chemical Corporation) on the other side was peeled off, and a tab (No. 315, manufactured by Nitto Denko Corporation) was attached to the adhesive surface of the second adhesive layer. Thereafter, an attempt was made to measure the peel strength against glass using the same method as in Example 1, but peeling between the slide glass and the adhesive layer was not possible. In such cases, the reusability of the transport carrier obtained by the above process was poor (marked x in the table).

[0082] Comparative Example 2 A pressure-sensitive adhesive sheet with a release liner (release liner / first pressure-sensitive adhesive layer) was obtained in the same manner as in Comparative Example 1, except that the thickness of the first pressure-sensitive adhesive layer was set to 50 μm. The obtained pressure-sensitive adhesive sheet was subjected to the same evaluation as in Comparative Example 1, but no peeling was possible between the slide glass and the pressure-sensitive adhesive layer. In such cases, the reusability of the transport carrier obtained by the above process was poor (marked x in the table).

[0083] Comparative Example 3 To an acrylic polymer solution D containing 100 parts by weight of acrylic polymer D, 2 parts by weight of a crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101A") and 2 parts by weight of Tetrad C were added to obtain a pressure-sensitive adhesive (1d). The pressure-sensitive adhesive (1d) was applied to a slide glass (manufactured by Matsunami Glass Co., Ltd., product name "S9111") by spin coating, and then heated at 130°C for 2 minutes to form a first pressure-sensitive adhesive layer with a thickness of 10 µm, thereby obtaining a pressure-sensitive adhesive sheet with a release liner (release liner / first pressure-sensitive adhesive layer). The release liner (Diafoil MRE38, manufactured by Mitsubishi Chemical Corporation) was peeled off, and the film was attached to a slide glass (manufactured by Matsunami Glass, trade name "S9111") using a hand roller. Thereafter, an attempt was made to measure the peel strength against glass using the same method as in Example 1, but peeling between the slide glass and the adhesive layer was not possible. In such cases, the reusability of the transport carrier obtained by the above process was poor (marked x in the table).

[0084] [Table 1]

[0085] The above results show that a double-sided pressure-sensitive adhesive sheet having an active energy ray-curable pressure-sensitive adhesive layer exhibits favorable adhesive strength to glass. By using such a double-sided pressure-sensitive adhesive sheet and carrying out the method for recycling a transport carrier including the above steps A to C, damage and contamination of the transport carrier can be prevented, and the "recyclability" of the transport carrier can be improved. [Explanation of symbols]

[0086] 1. Adhesive layer 10 double-sided adhesive sheet 100 Double-sided adhesive sheet transport carrier

Claims

1. A step A of placing an article to be transported on a transport carrier with a double-sided adhesive sheet, the transport carrier having a transport carrier and a double-sided adhesive sheet disposed on one side of the transport carrier; a step B of peeling the article from the transport carrier with the double-sided adhesive sheet, the step B including irradiating the double-sided adhesive sheet with active energy rays and then irradiating it with laser light; and step C of peeling the double-sided PSA sheet from the transport carrier; The double-sided pressure-sensitive adhesive sheet has an active energy ray-curable pressure-sensitive adhesive layer. How to reuse transport carriers.

2. The method for recycling a transport carrier according to claim 1 , wherein the transport carrier is laser-transparent.

3. 2. The method for recycling a transport carrier according to claim 1, wherein the step A is a step of receiving electronic components by a laser lift-off process.

4. In the step B, the amount of active energy ray irradiation is 100 mJ / cm ２ 2. The method for recycling a transport carrier according to claim 1, wherein:

5. 2. The method for recycling a transport carrier according to claim 1, wherein in step C, the adhesive strength of the double-sided adhesive sheet to the transport carrier at 23°C is 0.15 N / 20 mm or less.

6. The method for recycling a transport carrier according to claim 1 , wherein the transported item is a mini LED or a micro LED.

7. the pressure-sensitive adhesive layer is made of an active energy ray-curable pressure-sensitive adhesive, The active energy ray-curable pressure-sensitive adhesive contains a polymer having an unsaturated double bond. The method for recycling a transport carrier according to claim 1 .

8. The method for recycling a transport carrier according to claim 1 , wherein the thickness of the adhesive layer is 50 μm or less.

9. 2. The method for recycling a transport carrier according to claim 1, wherein in step C, the double-sided adhesive sheet is peeled off by attaching a tab to the double-sided adhesive sheet and peeling off the double-sided adhesive sheet integrated with the tab.

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