Peeling method

Abstract

The present application relates to a peeling method which is a method of peeling an adherend from an adhesive layer by irradiating light to a laminate in which the adhesive layer and the adherend are laminated, thereby peeling the adherend from the adhesive layer, comprising irradiating the adhesive layer with light having a pulse width of 1 second or less and a light irradiation amount of 1000 mJ / cm 2 In the above light process, the minimum transmittance of the adhesive layer in the near-infrared region of wavelengths of 800 nm to 2500 nm and the maximum transmittance of the adhesive layer in the visible light region of wavelengths of 380 nm to 780 nm satisfy prescribed conditions.

Description

Technical Field

[0001] The present invention relates to a method for peeling the adhesive layer off by irradiating a laminate containing an adhesive layer and an adhesive layer with high-energy light. Background Technology

[0002] As is well known, laminates formed by bonding adherends together using adhesive layers are widely used in various fields. On the other hand, in recent years, due to increased environmental awareness and cost reduction, there is a growing demand for resource conservation and recycling. For example, in the automotive, machinery, electrical appliance, and building materials industries, there is a need to improve yield, reprocessability, recyclability, and operability within processes.

[0003] In the case where the adhered material in the aforementioned laminate is a very brittle or hard material, there is a problem that the reprocessability is significantly reduced. For example, from the point of view of product design, the adhesive layer is required to ensure sufficient adhesion, but when at least one adhered material is a hard material such as glass, it is impossible to bend the adhered material along the peeling direction, and considering the possibility of glass breakage, the peeling of the two is usually difficult.

[0004] As a prior art for peeling an adhesive layer from an adhesive layer, for example, Patent Document 1 discloses a method for peeling an adhesive laminate, which is a method for peeling an adhesive laminate having at least an adhesive layer containing thermally expandable microparticles and an adhesive layer having an adhesive layer laminated with an adhesive layer, wherein the adhesive laminate contains a pigment component, and the pigment component is irradiated with a laser light of the same wavelength as the absorption wavelength of the pigment component, and the thermally expandable microparticles are expanded by the heat generated therefrom, thereby peeling the adhesive layer from the adhesive layer.

[0005] Furthermore, Patent Document 2 discloses a method for manufacturing an electronic composite component, which includes: a step of forming a temporary adhesive layer on a substrate comprising a material that softens or decomposes upon irradiation with light; a step of coating the temporary adhesive layer with conductive ink; a step of firing the conductive ink to form a wiring layer; a step of bonding an insulating member to the wiring layer; and a step of peeling the insulating member bonded to the wiring layer from the temporary adhesive layer by irradiating the temporary adhesive layer with light, thereby softening or decomposing the temporary adhesive layer.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2013-159743

[0009] Patent Document 2: Japanese Patent Application Publication No. 2017-45829 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, the technology in Patent Document 1 requires scanning point-like laser beams to irradiate the entire surface of the adhesive, and the process takes time, so there is room for further improvement.

[0012] In Patent Document 2, the irradiation of the temporary adhesive layer specifically refers to the irradiation of the entire surface of the temporary adhesive layer by a xenon flash lamp, which softens or decomposes the urethane resin contained in the temporary adhesive layer, thereby peeling the insulating component off the temporary adhesive layer.

[0013] However, in the technology disclosed in Patent Document 2, in order to rapidly soften or decompose the aforementioned temporary adhesive layer, the temporary adhesive layer needs to substantially contain more than 1 wt% carbon black as a flash-absorbing material. Since flash-absorbing materials like carbon black have the property of absorbing all visible light, such light-absorbing materials cannot be used in the adhesive layer when optical transparency is required for the laminate, and countermeasures are needed.

[0014] Therefore, the object of the present invention is to provide a method for having good light transmittance in the visible light region in a laminate having an adherend and an adhesive layer, while the adherend can be easily peeled off from the adhesive layer using high-energy light.

[0015] Methods for solving problems

[0016] The present invention is described below.

[0017] [1]

[0018] A peeling method, characterized in that, by irradiating a laminate containing an adhesive layer and an adherend with light, the adherend is peeled from the adhesive layer.

[0019] The aforementioned method includes irradiating the aforementioned adhesive layer with a pulse width of less than 1 second and a light irradiation dose of 1000 mJ / cm. 2 The above light-related processes,

[0020] Regarding the aforementioned adhesive layer, the minimum transmittance in the near-infrared region with wavelengths of 800 nm to 2500 nm and the maximum transmittance in the visible light region with wavelengths of 380 nm to 780 nm, measured using a test sample formed by bonding a 0.7 mm thick alkali-free glass to one adhesive surface of the aforementioned adhesive layer and sandwiching the other adhesive surface, satisfy the following conditions (1) and (2):

[0021] (1) The aforementioned minimum transmittance is below 75%;

[0022] (2) The value obtained by dividing the aforementioned maximum transmittance by the aforementioned minimum transmittance is 1.15 or higher.

[0023] [2]

[0024] The stripping method described in [1] above, wherein the aforementioned light is irradiated multiple times.

[0025] [3]

[0026] The stripping method described in [1] or [2] above, wherein the aforementioned light has a peak in the near-infrared region with a wavelength of 800 nm to 2500 nm.

[0027] [4]

[0028] The peeling method as described in any one of [1] to [3] above, wherein the light irradiation dose of the aforementioned light is 1000 mJ / cm 2 ~100000mJ / cm 2 .

[0029] [5]

[0030] The peeling method as described in any one of [1] to [4] above, wherein the aforementioned adhesive layer comprises an acrylic adhesive.

[0031] [6]

[0032] The peeling method as described in any one of [1] to [5] above, wherein the aforementioned adhesive layer comprises a near-infrared absorbing material.

[0033] [7]

[0034] The peeling method described in [6] above, wherein the aforementioned near-infrared absorbing material is a near-infrared absorbing pigment.

[0035] The effects of the invention

[0036] According to the present invention, a method is provided that provides good light transmittance in the visible light region in a laminate containing an adhesive layer and an adherend, while allowing the adherend to be easily peeled off from the adhesive layer using high-energy light. Attached Figure Description

[0037] [ Figure 1 ] Figure 1 This is a cross-sectional view of a laminate used to illustrate a peeling method according to one embodiment of the present invention.

[0038] [ Figure 2 ] Figure 2 This is a transmission spectrum diagram of a measurement sample from a subset of embodiments and comparative examples, which used an adhesive sheet with an adhesive layer thickness of 50 μm.

[0039] [ Figure 3 ] Figure 3 This is a transmission spectrum diagram of a measurement sample from a subset of embodiments and comparative examples, which used an adhesive sheet with an adhesive layer thickness of 50 μm.

[0040] [ Figure 4 ] Figure 4 The transmission spectrum of the test sample in the comparative example, which used an adhesive sheet with an adhesive layer thickness of 50 μm, is shown.

[0041] [ Figure 5 ] Figure 5 These are photographs used to illustrate the transmittance of the test samples used in some of the embodiments and comparative examples. Detailed Implementation

[0042] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. For ease of explanation, only preferred embodiments of the present invention are shown below; however, the present invention is not limited thereto.

[0043] Figure 1 This is a cross-sectional view of a laminate used to illustrate a peeling method according to one embodiment of the present invention.

[0044] Figure 1 In this embodiment, the laminate 1 is formed by laminating the adherend 12 and the adherend 16 through an adhesive layer 14. By irradiating the laminate 1 with light, the adherend 12 and the adherend 16 are peeled off from the adhesive layer 14.

[0045] The characteristic of this embodiment is that the irradiation pulse width of the adhesive layer 14 is less than 1 second, and the light irradiation dose is 1000 mJ / cm. 2 The above light (also known as high-energy light), and with regard to the adhesive layer 14, the minimum transmittance in the near-infrared region with a wavelength of 800nm ​​to 2500nm and the maximum transmittance in the visible light region with a wavelength of 380nm to 780nm, measured by a test sample made by bonding a 0.7mm thick alkali-free glass to one adhesive surface of the adhesive layer and sandwiching the other adhesive surface of the adhesive layer, satisfy the following conditions (1) and (2).

[0046] (1) The aforementioned minimum transmittance is below 75%.

[0047] (2) The value obtained by dividing the aforementioned maximum transmittance by the aforementioned minimum transmittance is 1.15 or higher.

[0048] It should be noted that in the peeling method of this embodiment, when the adhered objects are stacked on both surfaces of the adhesive layer, at least one adhered object is peeled off. That is, only one adhered object can be peeled off, or both adhered objects can be peeled off.

[0049] in addition, Figure 1 The laminate 1 indicates that the adherends are laminated on both surfaces of the adhesive layer, but a substrate, release liner, etc., can also be provided instead of one adherend. In this case, by the peeling method in this embodiment, only the other adherend is peeled off from the adhesive layer 14.

[0050] in addition, Figure 1 The laminate 1 forms a three-layer structure consisting of an adherend 12, an adhesive layer 14, and an adherend 16. However, as long as the adhesive layer is in contact with at least a portion of the adherend, the peeling method of this embodiment can be applied. Therefore, there is no limitation on the number of layers, and a laminate with a total of four or more layers can be formed with any other layers in between.

[0051] <Adhesive layer>

[0052] As the adhesive layer 14 in this embodiment, it is acceptable as long as the aforementioned conditions (1) and (2) are met, and there are no particular restrictions. For example, representative examples of adhesives constituting the adhesive layer include acrylic adhesives, urethane adhesives, and rubber adhesives.

[0053] From the perspective of excellent transparency, acrylic adhesives containing acrylic polymers are preferred. Acrylic adhesives typically contain (meth)acrylic polymers as the main component. It should be noted that, in this specification, the term "main component" refers to the component with the highest content among all components, for example, a component that accounts for 50% or more by mass.

[0054] (Meth)acrylate polymers may be included in the solid components of the adhesive composition at a proportion of, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more. The (meth)acrylate polymer contains alkyl (meth)acrylates as monomer units as the main component. It should be noted that (meth)acrylates refer to acrylates and / or methacrylates.

[0055] As the main backbone of (meth)acrylic polymers, alkyl (meth)acrylates can be exemplified by compounds with 1 to 18 carbon atoms in the linear or branched alkyl groups.

[0056] Examples of the aforementioned alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, decyl, isodecyl, dodecyl, isomycinyl, lauryl, tridecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, etc. These can be used alone or in combination. The average number of carbon atoms in these alkyl groups is preferably 3 to 9.

[0057] In the aforementioned (meth)acrylic polymers, in addition to the aforementioned alkyl methacrylate monomer units, monomers containing functional groups, such as those containing carboxyl groups, hydroxyl groups, or amide groups, can be introduced to improve adhesion and heat resistance.

[0058] Monomers containing carboxyl groups are compounds that contain carboxyl groups in their structure, as well as polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups.

[0059] Specific examples of monomers containing a carboxyl group include (meth)acrylic acid, carboxyethyl methacrylate, carboxypentyl methacrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc.

[0060] Among the aforementioned monomers containing carboxyl groups, acrylic acid is preferred from the viewpoints of copolymerization, price, and adhesive properties.

[0061] A monomer containing hydroxyl groups is a compound whose structure contains hydroxyl groups and polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups.

[0062] Specific examples of monomers containing hydroxyl groups include 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl methacrylate, 10-hydroxydecyl methacrylate, 12-hydroxylaurate methacrylate, hydroxyalkyl methacrylate, and methyl acrylate (4-hydroxymethylcyclohexyl) acrylate.

[0063] Among the aforementioned monomers containing hydroxyl groups, from the perspective of durability, 2-hydroxyethyl methacrylate and 4-hydroxybutyl methacrylate are preferred, and 4-hydroxybutyl methacrylate is particularly preferred.

[0064] Monomers containing amide groups are compounds that contain amide groups in their structure, as well as polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups.

[0065] Specific examples of monomers containing amide groups include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxymethyl-N-propane(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl(meth)acrylamide, mercaptoethyl(meth)acrylamide, and other acrylamide monomers; N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, and other N-acryloyl heterocyclic monomers; and N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and other N-vinyl lactam monomers.

[0066] The adhesive layer 14 preferably contains a near-infrared absorbing material. In this manner, if the aforementioned high-energy light has a peak in the near-infrared region with wavelengths of 800 nm to 2500 nm, and the adhesive layer 14 is irradiated with such high-energy light, the adhesive contained in the adhesive layer 14 becomes easier to decompose or soften, and the adhered material can be more easily peeled off from the adhesive layer 14.

[0067] Near-infrared absorbing materials can be exemplified by near-infrared absorbing pigments. There are no particular limitations as long as the near-infrared absorbing pigment can absorb light in the wavelength range of 800nm ​​to 2500nm.

[0068] Examples of near-infrared absorbing materials include, for example, anthocyanin pigments, phthalocyanine pigments, naphthyl phthalocyanine pigments, ammonium pigments, aminoonium pigments, quinolineonium pigments, pyranonium pigments, Ni complex pigments, pyrrolopyrrole pigments, copper complex pigments, quaterrylene pigments, azo pigments, anthraquinone pigments, diimide pigments, squaric acid cyanide pigments, and porphyrin pigments. Among these, diimide pigments are preferred.

[0069] In this embodiment, the diammonium pigment can be an amorphous form of a diammonium salt represented by the following formula (1).

[0070] [Chemical Formula 1]

[0071]

[0072] In equation (1), R 1 ~R 8 X represents a monovalent organic group that can be the same or different. - It represents anion.

[0073] It should be noted that, in this specification, amorphous solids refer to a solid state in which atoms or molecules are not arranged in a regular, periodic pattern. The presence or absence of crystallinity in a solid is determined by measuring the diffraction pattern using an X-ray powder diffraction apparatus. That is, an amorphous solid is a state in which no distinct diffraction peaks indicating crystallinity are detected in the diffraction pattern obtained by an X-ray powder diffraction apparatus.

[0074] For example, consider a solid whose diffraction peaks, when measured using an X-ray powder diffraction apparatus, show a half-width of 2θ = 1° or greater when the peak is taken from the baseline at its apex among the peaks of maximum intensity detected. Such a solid is essentially devoid of crystals and consists only of amorphous matter.

[0075] By using the amorphous form of diammonium salt (1) as a near-infrared absorbing pigment, it exhibits high heat resistance, high resistance to damp heat, and excellent transparency when contained in the adhesive layer 14, compared to a crystalline state such as crystals or associative compounds.

[0076] As R 1 ~R 8 Preferred organic groups include linear or branched C groups that can be substituted with halogen atoms. 1-10 alkyl, C 3-12 Cycloalkyl, cycloalkyl ring can be substituted C 3-12 cycloalkyl-C 1-10 Alkyl groups, etc.

[0077] C as a straight chain or branched chain 1-10 Alkyl groups, such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, 1-methylbutyl, 2-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 2-dimethylpropyl, 1,1-dimethylpropyl, etc.

[0078] Among these, the crystallinity of the diammonium salt (1) decreases in the cases of n-propyl, n-butyl, n-pentyl, and n-hexyl, making it more likely to become an amorphous substance, and therefore it is preferred. In addition, the low polarity of the alkyl group makes it close to the polarity of acrylic adhesives, which facilitates mixing, and this is also a preferred consideration.

[0079] As C 3-12 Cycloalkyl groups, for example, include cyclopentyl and cyclohexyl.

[0080] As C 3-12 cycloalkyl-C 1-10Alkyl and cycloalkyl rings may be substituted or unsubstituted. Examples of substituted substituents include alkyl, hydroxyl, sulfonic acid, alkylsulfonic acid, nitro, amino, alkoxy, haloalkyl, or halogen atoms. Unsubstituted is preferred, as cycloalkyl-alkyl groups represented by the following general formula (3) have low solubility in acrylic adhesives.

[0081] [Chemical Formula 2]

[0082]

[0083] In the above general formula (3), A represents a straight-chain or branched alkyl group having 1 to 10 carbon atoms, and m represents an integer from 3 to 12. The number of carbon atoms in A is preferably 1 to 4. In addition, m is preferably 5 to 8, and more preferably 5 or 6.

[0084] Specifically, examples of the cycloalkyl-alkyl group of the above general formula (3) include cyclopentylmethyl, 2-cyclopentylethyl, 2-cyclopentylpropyl, 3-cyclopentylpropyl, 4-cyclopentylbutyl, 2-cyclohexylmethyl, 2-cyclohexylethyl, 3-cyclohexylpropyl, and 4-cyclohexylbutyl, among which cyclopentylmethyl, cyclohexylmethyl, 2-cyclohexylethyl, 2-cyclohexylpropyl, 3-cyclohexylpropyl, and 4-cyclohexylbutyl are preferred.

[0085] As for the cycloalkyl-alkyl group of the above general formula (3), cyclopentylmethyl or cyclohexylmethyl is more preferred. In particular, cyclohexylmethyl has low solubility and low polarity in acrylic resins used in adhesives, hard coating resins, etc., and is therefore more preferred.

[0086] Additionally, C can be a straight-chain or branched chain with halogen atom substitution. 1-10 Alkyl groups, including 2-haloethyl, 2,2-dihaloethyl, 2,2,2-trihaloethyl, 3-halopropyl, 3,3-dihalopropyl, 3,3,3-trihalopropyl, 4-halobutyl, 4,4-dihalobutyl, 4,4,4-trihalobutyl, 5-halopentyl, 5,5-dihalopentyl, and 5,5,5-trifluoropentyl, are among the halogenated alkyl groups. Preferably, monohalogenated alkyl groups represented by the following general formula (4) are preferred.

[0087] -C n H 2n -CH2Y(4)

[0088] In the above general formula (4), n represents an integer from 1 to 9, and Y represents a halogen atom.

[0089] n is preferably 1 to 4. In addition, it is particularly preferred that Y is a fluorine atom. Specifically, examples of monohaloalkyl groups represented by the above general formula (4) include 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, and 5-fluoropentyl monofluoroalkyl groups.

[0090] R in general formula (1) 1 ~R 8 It can consist entirely of the same monovalent organic group, or it can consist of two or more different monovalent organic groups, preferably two different monovalent organic groups. R is particularly preferred. 1 With R 2 R 3 With R 4 R 5 With R 6 and R 7 With R 8 Each combination is a combination of two different monovalent organic groups. That is, it is suitable for a diammonium salt (1) in which the two monovalent organic groups in each amino group are combinations of two different monovalent organic groups.

[0091] Preferably, the two monovalent organic groups are combinations of monovalent organic groups selected from the group consisting of n-propyl, n-butyl, n-pentyl, n-hexyl, and cyclohexylmethyl. More preferably, one monovalent organic group is cyclohexylmethyl, and the other monovalent organic group is a monovalent organic group selected from the group consisting of n-propyl, n-butyl, n-pentyl, and n-hexyl.

[0092] By making the monovalent organic group of one amino group a combination of two different monovalent organic groups, the crystallinity of the diammonium salt (1) is reduced, making it more likely to become an amorphous substance. In particular, when one of the two monovalent organic groups is cyclohexylmethyl, the crystallinity is reduced due to steric hindrance, making it more likely to become an amorphous substance, which is therefore preferred.

[0093] X in general formula (1) - It is the anion required to neutralize the charge of the diammonium cation, and can be organic acid anions, inorganic anions, etc.

[0094] Specifically, examples of anions include halogen ions such as fluoride ions, chloride ions, bromide ions, and iodide ions, as well as perchlorate ions, periodate ions, tetrafluoroborate ions, hexafluorophosphate ions, hexafluoroantimonate ions, bis(trifluoromethanesulfonyl)imide ions, and bis(fluorosulfonyl)imide ions.

[0095] Among these, tetrafluoroborate ions, hexafluorophosphate ions, hexafluoroantimonate ions, bis(trifluoromethanesulfonyl)imide ions, and bis(fluorosulfonyl)imide ions are particularly preferred as anions. This is because they can improve the heat resistance and damp heat resistance of the resulting adhesive layer.

[0096] In particular, hexafluorophosphate ions, hexafluoroantimonate ions, and bis(fluorosulfonyl)imide ions are highly inorganic, and the resulting diammonium salts have low solubility in acrylic adhesives, thus they are preferred.

[0097] As a diammonium salt (1), specifically, considering excellent heat resistance, damp heat resistance, and transparency, the preferred choices are hexafluorophosphate-N,N,N',N'-tetra{p-di(cyclohexylmethyl)aminophenyl}-p-phenylene diammonium, hexafluoroantimonylic acid-N,N,N',N'-tetra{p-di(cyclohexylmethyl)aminophenyl}-p-phenylene diammonium, bis(trifluoromethanesulfonyl)imino acid-N,N,N',N'-tetra{p-di(cyclohexylmethyl)aminophenyl}-p-phenylene diammonium, bis(fluorosulfonyl)imino acid-N,N,N',N'-tetra{p-di(cyclohexylmethyl)aminophenyl}-p-phenylene diammonium, and hexafluorophosphate-N,N,N', N'-Tetra{p-di(n-propyl)aminophenyl}-p-phenylene diimide, hexafluoroantimonic acid -N,N,N',N'-tetra{p-di(n-propyl)aminophenyl}-p-phenylene diimide, bis(trifluoromethanesulfonyl)imino acid -N,N,N',N'-tetra{p-di(n-propyl)aminophenyl}-p-phenylene diimide, bis(fluorosulfonyl)imino acid -N,N,N',N'-tetra{p-di(n-propyl)aminophenyl}-p-phenylene diimide, hexafluorophosphate -N,N,N',N'-tetra{p-di(n-butyl)aminophenyl}-p-phenylene diimide, hexafluoroantimonic acid -N,N,N',N'-tetra{p-di(n-butyl)aminophenyl}-p-phenylene diimide Diaminoimide, bis(trifluoromethanesulfonyl)imino acid -N,N,N',N'-tetra{p-di(n-butyl)aminophenyl}-p-phenylene diaminoimide, bis(fluorosulfonyl)imino acid -N,N,N',N'-tetra{p-di(n-butyl)aminophenyl}-p-phenylene diaminoimide, hexafluoroantimonylic acid -N,N,N',N'-tetra{p-di(n-pentyl)aminophenyl}-p-phenylene diaminoimide, bis(fluorosulfonyl)imino acid -N,N,N',N'-tetra{p-di(n-pentyl)aminophenyl}-p-phenylene diaminoimide, hexafluorophosphate -N,N,N',N'-tetra{p-(cyclohexylmethyl-n-propyl)aminophenyl}-p-phenylene diaminoimide, bis(fluorosulfonyl) (N,N,N',N'-tetra(cyclohexylmethyl-n-propyl)aminophenyl)-p-phenylene diimide, hexafluorophosphate -N,N,N',N'-tetra(cyclohexylmethyl-n-butyl)aminophenyl)-p-phenylene diimide, bis(fluorosulfonyl)imide -N,N,N',N'-tetra(cyclohexylmethyl-n-butyl)aminophenyl)-p-phenylene diimide, hexafluorophosphate -N,N,N',N'-tetra(cyclohexylmethyl-n-pentyl)aminophenyl)-p-phenylene diimide, bis(fluorosulfonyl)imide -N,N,N',N'-tetra(cyclohexylmethyl-n-pentyl)aminophenyl)-p-phenylene diimide, etc.

[0098] Among these, considering their low crystallinity and greater tendency to become amorphous, the following are particularly preferred: hexafluorophosphate-N,N,N',N'-tetra{p-di(cyclohexylmethyl)aminophenyl}-p-phenylene diimide, bis(trifluoromethanesulfonyl)imino acid-N,N,N',N'-tetra{p-di(cyclohexylmethyl)aminophenyl}-p-phenylene diimide, bis(fluorosulfonyl)imino acid-N,N,N',N'-tetra{p-di(cyclohexylmethyl)aminophenyl}-p-phenylene diimide, and hexafluorophosphate-N,N,N',N'-tetra{p-di(n-propyl)aminophenyl}-p-phenylene diimide. Hexafluoroantimonylic acid -N,N,N',N'-tetra{p-di(n-butyl)aminophenyl}-p-phenylene diimide, bis(fluorosulfonyl)imine acid -N,N,N',N'-tetra{p-di(n-butyl)aminophenyl}-p-phenylene diimide, hexafluoroantimonylic acid -N,N,N',N'-tetra{p-di(n-pentyl)aminophenyl}-p-phenylene diimide, hexafluorophosphate -N,N,N',N'-tetra{p-(cyclohexylmethyln-propyl)aminophenyl}-p-phenylene diimide, hexafluorophosphate -N,N,N',N'-tetra{p-(cyclohexylmethyln-butyl)aminophenyl}-p-phenylene diimide, etc.

[0099] The diammonium-based pigment used in this embodiment is obtained by dry pulverizing a crystalline solid of diammonium salt (1) to make it amorphous. The crystalline solid of diammonium salt (1) can be manufactured using conventionally known methods, such as the method described in International Publication No. 2011 / 074619. In addition, the amorphization of the crystalline solid of diammonium salt (1) based on dry pulverization can also be carried out using the method described in International Publication No. 2011 / 074619.

[0100] As a diammonium-based pigment, commercially available products can be used, such as CIR-RL (bis(trifluoromethanesulfonyl)imide) and CIR-FS265 manufactured by Carlit Corporation of Japan.

[0101] The adhesive layer 14 may contain one of the amorphous forms of the aforementioned diammonium salt (1) as a diammonium-based pigment, or it may contain two or more as diammonium-based pigments.

[0102] The content of near-infrared absorbing pigment in adhesive layer 14 is, for example, 50% or less by mass, preferably 20% or less by mass, more preferably 10% or less by mass, further preferably 5% or less by mass, further preferably 2% or less by mass, further preferably 1% or less by mass, and particularly preferably 0.1% or less by mass, relative to 100% by mass of the adhesive composition 14 used to form adhesive layer 14.

[0103] In addition, relative to 100% by mass of the adhesive composition described above, the content of near-infrared absorbing pigment in the adhesive layer 14 is, for example, 0.01% by mass or more, preferably 0.05% by mass or more, and more preferably 0.1% by mass or more.

[0104] In addition, the adhesive layer 14 may contain polymerization initiators such as thermal polymerization initiators and photopolymerization initiators.

[0105] There are no particular limitations on the type of initiator used for thermal polymerization. For example, azo polymerization initiators, peroxide initiators, redox initiators based on the combination of peroxide and reducing agent, and substituted ethane initiators can be used.

[0106] More specifically, examples include: azo-based initiators such as 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylpropanedisulfate), 2,2'-azobis(2-amidinepropane)dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(N,N'-dimethyleneisobutanediidine), and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediidine] hydrate; persulfates such as potassium persulfate and ammonium persulfate; peroxide-based initiators such as benzoyl peroxide, tert-butyl hydroperoxide, and hydrogen peroxide; substituted ethane initiators such as phenyl-substituted ethane; redox initiators such as combinations of persulfates and sodium bisulfite, and combinations of peroxides and sodium ascorbate; and so on.

[0107] There are no particular limitations on the aforementioned photopolymerization initiators. Examples include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-keto alcohol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzoyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanone-based photopolymerization initiators.

[0108] Specifically, examples of ketal photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethane-1-one (trade name "Irgacure 651", manufactured by BASF Japan).

[0109] Examples of α-hydroxyketone photopolymerization initiators include 1-hydroxy-cyclohexyl-phenyl ketone (trade name "Irgacure 184", manufactured by BASF Japan), 2-hydroxy-2-methyl-1-phenyl-propane-1-one (trade name "Darocur 1173", manufactured by BASF Japan), and 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (trade name "Irgacure 2959", manufactured by BASF Japan).

[0110] Examples of α-aminoketone photopolymerization initiators include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one (trade name "Irgacure 907", manufactured by BASF Japan) and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (trade name "Irgacure 369", manufactured by BASF Japan).

[0111] Examples of acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyl diphenylphosphine oxide (trade name "LUCIRIN TPO", manufactured by BASF Japan).

[0112] Examples of benzoin ether-based photopolymerization initiators include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, and anisole methyl ether.

[0113] Examples of acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4-tert-butyl-dichloroacetophenone.

[0114] Examples of aromatic sulfonyl chloride photopolymerization initiators include 2-naphthalenesulfonyl chloride.

[0115] Examples of photoactive oxime photopolymerization initiators include, for example, 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.

[0116] Examples of benzoin-based photopolymerization initiators include benzoin itself.

[0117] Examples of benzoyl photopolymerization initiators include benzoyl and the like.

[0118] Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone.

[0119] Examples of photopolymerization initiators for ketal systems include benzyl dimethyl ketal.

[0120] Examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0121] The content of the polymerization initiator in the adhesive layer 14 varies depending on its type and is not particularly limited. For example, when using an acrylic adhesive composition, the content of the polymerization initiator is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 5 parts by weight, and even more preferably 0.05 to 3 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer.

[0122] In addition, from the viewpoint of adjusting its elasticity, softness, or improving cohesion to enhance adhesion, the adhesive layer 14 may also contain other functional monomers, which contain monomers having two or more olefinic unsaturated bonds within the molecule.

[0123] Examples of multifunctional monomers include, for instance, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and polyethylene glycol di(meth)acrylate. Acrylic esters, hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl methacrylate, vinyl methacrylate, epoxy acrylate, polyester acrylate, urethane acrylate, reactive hyperbranched polymers with multiple (meth)acryloyl groups at the ends (e.g., trade names “CN2300”, “CN2301”, “CN2320” manufactured by SARTOMER), etc.

[0124] The content of the multifunctional monomer in the adhesive layer 14 is not particularly limited. For example, when using an acrylic adhesive composition, the content of the multifunctional monomer is, for example, 0.001 to 5 parts by weight, preferably 0.001 to 3 parts by weight, and more preferably 0.001 to 1 part by weight, relative to 100 parts by weight of the (meth)acrylic polymer.

[0125] Alternatively, various known additives may be added to the adhesive layer 14 as needed, without compromising the effectiveness of the invention.

[0126] Examples of additives include, for instance, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and other crosslinking agents; adhesives such as rosin derivative resins, polyterpene resins, petroleum resins, and oil-soluble phenolic resins; plasticizers; fillers; anti-aging agents; surfactants; and chain transfer agents. It should be noted that additives may contain one or more types.

[0127] The thickness of the adhesive layer 14 is not particularly limited, but from the perspective of achieving reliability and peelability of the adhesive layer 14, it is preferably 5000 μm or less, more preferably 1000 μm or less, even more preferably 500 μm or less, even more preferably 250 μm or less, even more preferably 100 μm or less, even more preferably 50 μm or less, even more preferably 25 μm or less, and particularly preferably 10 μm or less.

[0128] Furthermore, the thickness of the adhesive layer 14 is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and particularly preferably 8 μm or more. It should be noted that the adhesive layer 14 can be a single-layer structure or a multi-layer structure.

[0129] The adhesive layer 14 is formed by applying an adhesive composition to the substrate to obtain an adhesive composition layer, and then drying and curing the adhesive composition layer as needed (e.g., curing using heat or active energy rays).

[0130] The aforementioned coating, drying, and curing can be carried out using conventional methods. For example, the coating of the adhesive composition can be performed using conventional coating machines, such as gravure roller coating machines, reverse roller coating machines, kiss roller coating machines, dip roller coating machines, bar coating machines, doctor blade coating machines, spray coating machines, etc.

[0131] On the other hand, regarding the adhesive layer 14, as shown in the following embodiments, an adhesive composition layer can be provided on the substrate as described above, and a release liner that has undergone a release treatment can be laminated to form an adhesive sheet. After storage as needed, the release liner can be peeled off during manufacturing to bond the adhesive sheet to the object to be bonded.

[0132] The adhesive layer 14 in this embodiment is characterized in that the minimum transmittance in the near-infrared region with a wavelength of 800nm ​​to 2500nm and the maximum transmittance in the visible light region with a wavelength of 380nm to 780nm, as measured using the following test sample, satisfy the following conditions (1) and (2), wherein the test sample is formed by bonding a 0.7mm thick alkali-free glass to one adhesive surface of the adhesive layer and sandwiching the other adhesive surface of the adhesive layer.

[0133] (1) The aforementioned minimum transmittance is below 75%.

[0134] (2) The value obtained by dividing the aforementioned maximum transmittance by the aforementioned minimum transmittance is 1.15 or higher.

[0135] It should be noted that the above-mentioned test sample is, in other words, a sample in which the adhesive layer 14 is sandwiched between alkali-free glass with a thickness of 0.7 mm.

[0136] If the aforementioned minimum transmittance exceeds 75%, high-energy light will not be absorbed by the adhesive layer 14, making it difficult to peel the adhered material from the adhesive layer 14.

[0137] The aforementioned minimum transmittance is preferably 70% or less, more preferably 68% or less, even more preferably 65% ​​or less, even more preferably 63% or less, even more preferably 60% or less, even more preferably 58% or less, even more preferably 55% or less, even more preferably 53% or less, even more preferably 50% or less, even more preferably 45% or less, and particularly preferably 40% or less. Furthermore, the aforementioned minimum transmittance is, for example, 0.000001% or more.

[0138] Furthermore, if the value obtained by dividing the aforementioned maximum transmittance by the aforementioned minimum transmittance is less than 1.15, then high-energy light is not easily absorbed by the adhesive layer 14, making it difficult to peel the adhered material from the adhesive layer, and it is not possible to easily peel it off using high-energy light while maintaining good light transmittance in the visible light region.

[0139] The value obtained by dividing the aforementioned maximum transmittance by the aforementioned minimum transmittance is 1.15 or more, preferably 1.20 or more, more preferably 1.25 or more, even more preferably 1.30 or more, even more preferably 1.35 or more, even more preferably 1.40 or more, even more preferably 1.50 or more, even more preferably 1.7 or more, even more preferably 2 or more, even more preferably 3 or more, and particularly preferably 5 or more. Furthermore, the value obtained by dividing the aforementioned maximum transmittance by the aforementioned minimum transmittance is, for example, 10000 or less, or 5000 or less.

[0140] It should be noted that the aforementioned maximum transmittance is preferably 20% or more, more preferably 30% or more, even more preferably 40% or more, even more preferably 50% or more, even more preferably 60% or more, even more preferably 70% or more, even more preferably 80% or more, and particularly preferably 90% or more. Furthermore, the aforementioned maximum transmittance is, for example, 99.9% or less, or 98% or less.

[0141] It should be noted that the aforementioned maximum transmittance and minimum transmittance in the adhesive layer 14 were measured using the aforementioned test sample, specifically, using the method described in the examples.

[0142] The aforementioned condition (1) can be met, for example, by setting the content of near-infrared absorbing pigment in the adhesive layer 14 as described above.

[0143] In addition, the aforementioned condition (2) can be satisfied by setting the content of near-infrared absorbing pigment in the adhesive layer 14 as described above, and by making the adhesive layer 14 free of or containing a small amount of materials such as carbon black that absorb light in the visible light region with wavelengths of 380nm to 780nm, etc., in a manner that satisfies the aforementioned condition (2).

[0144] <Object to be glued>

[0145] Examples of materials that can be adhered to in this embodiment include resins, glass, silicon wafers, inorganic materials, and metallic materials that can transmit high-energy light. Figure 1 As shown, when there are two or more adhered materials, they can be the same material or different materials. Furthermore, as long as high-energy light can reach the adhesive layer 14, at least one of the adhered materials can also be a material that cannot transmit high-energy light.

[0146] Examples of resins used in the adherends include transparent resins formed from homopolymers and copolymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polyvinyl chloride, polycarbonate (PC), cyclic olefin polymers (COP), polystyrene, polypropylene (PP), polyethylene, polycyclic olefins, polyurethane, polyimide, acrylic polymers (PMMA), and ABS.

[0147] Glass as an adhering material includes, for example, alkali-free glass, soda glass, borosilicate glass, aluminosilicate glass, etc.

[0148] Inorganic materials used in the adherend can include inorganic bulk materials and inorganic thin films, with inorganic thin films being preferred from the viewpoint of light transmittance. Examples of inorganic thin films include carbon-based films such as graphite and graphene, and nitride-based films such as boron nitride.

[0149] The thickness of the inorganic thin film is, for example, 0.3 nm or more, 1 nm or more, or 3 nm or more. Alternatively, the thickness of the inorganic thin film is, for example, 10 μm or less, 5 μm or less, or 1 μm or less.

[0150] From the viewpoint of light transmittance, metal thin films are preferred as the metallic material in the adhered material. Examples of metal thin films include, for instance, metal oxide thin films such as ITO, Al2O3, ZnO, and SiO, and metal nitride thin films such as SiN.

[0151] The thickness of the metal thin film is, for example, 1 nm or more, 3 nm or more, or 5 nm or more. Alternatively, the thickness of the metal thin film is, for example, 10 μm or less, 5 μm or less, or 1 μm or less.

[0152] Among these considerations, glass, resin, and silicon wafers are preferred as the adherends, taking into account factors such as achieving the separation of the rigid body from the adhesive layer, which was previously difficult to achieve, and the fact that they are not easily heated by high-energy light.

[0153] The thickness of the adherend can be appropriately set according to the application. From the viewpoint of the reachability of high-energy light to the adhesive layer 14, it is, for example, 100 mm or less, preferably 50 mm or less, more preferably 10 mm or less, even more preferably 5 mm or less, even more preferably 3 mm or less, even more preferably 1 mm or less, and particularly preferably 0.5 mm or less.

[0154] The minimum thickness of the adhered material is preferably 1 μm or more in the case of a film. In the case of glass, it is preferably 0.1 mm or more, and more preferably 0.3 mm or more.

[0155] It should be noted that, Figure 1 In the laminate 1 shown, the shape of the adhered object is planar, but the present invention is not limited to this shape. The shape of the adhered object can be freely changed according to the application, as long as high-energy light can reach the adhesive layer 14.

[0156] <Light Irradiation Process>

[0157] The peeling method of this embodiment includes irradiating the adhesive layer with a pulse width of less than 1 second and a light irradiation dose of 1000 mJ / cm. 2 The above light process. This light is high-energy and short-pulse light, so by decomposing or softening the adhesive layer that is the object being irradiated by the light, the adhered material can be peeled off from the adhesive layer.

[0158] The light used in this process preferably includes multiple continuous wavelength bands.

[0159] The pulse width of the light used in this process is preferably 0.5 seconds or less, more preferably 0.1 seconds or less, even more preferably 0.05 seconds or less, even more preferably 0.01 seconds or less, and particularly preferably 0.001 seconds (1000 μs) or less.

[0160] The number of light pulses irradiated in this process can be one or more. For example, the number of light pulses irradiated in this process can be more than two, three, five, ten, one hundred, one thousand, one hundred thousand, one million, or one hundred million. Alternatively, the number of light pulses irradiated in this process can be less than one billion, less than one billion, less than one hundred million, or less than one hundred million.

[0161] Here, the number of light pulses irradiated in the above-mentioned process refers to the number of pulses contained in the single irradiation when the light irradiation is performed once, and the total number of pulses contained in the multiple irradiation sessions when the light irradiation is performed multiple times.

[0162] The exposure time of the light used in this process is preferably 10 μs or more, more preferably 50 μs or more, even more preferably 100 μs or more, even more preferably 1000 μs or more, and particularly preferably 10000 μs or more.

[0163] The exposure time of the light used in this process is preferably less than 100 seconds, more preferably less than 50 seconds, even more preferably less than 30 seconds, and particularly preferably less than 10 seconds.

[0164] Here, the exposure time mentioned above refers to the exposure time of one illumination session. That is, if one illumination session contains one pulse, the exposure time is equal to the pulse width. Alternatively, if one illumination session contains multiple pulses, the exposure time is equal to the sum of the pulse width and the pulse interval.

[0165] The number of times the light is applied in this process can be once or multiple times. For example, the number of times the light is applied in this process can be 2 or more, 3 or more, 5 or more, or 10 or more. Alternatively, the number of times the light is applied in this process can be less than 100, less than 80, or less than 50.

[0166] Furthermore, a single irradiation can contain one or more pulses. For example, a single irradiation can contain two or more, three or more, five or more, ten or more, one hundred or more, one thousand or more, one hundred thousand or more, one million or more, or one million or more. Alternatively, a single irradiation can contain fewer than one hundred billion, fewer than one billion, fewer than one hundred million, or fewer than one million.

[0167] From the viewpoint that it is easier to peel the adhered material from the adhesive layer 14, the light used in this process preferably has a peak in the near-infrared region with a wavelength of 800 nm to 2500 nm, and more preferably has a peak in the near-infrared region with a wavelength of 800 nm to 1500 nm.

[0168] Furthermore, from the viewpoint that it is easier to peel the adhered material from the adhesive layer 14, the light irradiation intensity used in this process is preferably 1000 mJ / cm². 2 ~100000mJ / cm 2 Furthermore, the light irradiation dose used in this process is preferably 2000 mJ / cm². 2 The above, more preferably 3000 mJ / cm 2 The above is further optimized to 4000 mJ / cm 2 The above is further optimized to 5000 mJ / cm 2 The above is further optimized to 7000 mJ / cm 2 The above is further optimized to 10000 mJ / cm. 2 The above is further optimized to 30000 mJ / cm. 2 The above, especially preferred, is 50000 mJ / cm. 2 above.

[0169] For example, the known flash annealing method can be used as the method of irradiation of light applied in this process.

[0170] The flash annealing method in this embodiment is as follows: for example, using a xenon lamp as the lamp, with a pulse width of less than 1 second and 1000 mJ / cm. 2 ~100000mJ / cm 2 The adhesive layer 14 is irradiated with light in the near-infrared region with a peak wavelength of 800nm ​​to 2500nm for a short time to heat-treat the adhesive layer 14, causing the adhesive contained in the adhesive layer 14 to decompose or soften.

[0171] Furthermore, according to the flash annealing method, it is possible to illuminate a wide area in a single pass. In principle, the illumination area can be increased by increasing the size of the lamp or the number of lamps, so there is no limit to the illumination area.

[0172] The irradiated area is, for example, 1 cm². 2 Above, 5cm 2 Above, 10cm 2 Above, 30cm 2 Above, 50cm 2 Above, 100cm 2 Above, 300cm2 Above, 500cm 2 Above, 1000cm 2 Above, or 10000cm 2 That's all. Additionally, the irradiated area is, for example, 1,000,000 cm². 2 the following.

[0173] It should be noted that the flash annealing method in this embodiment can be implemented using commercially available devices, such as an intermittent flash illumination device (NovaCentrix, PulseForge 1300X2 lamp).

[0174] In the case of flash annealing, the light irradiation time is very short, so it is preferable not to heat materials that do not absorb light, such as glass. Furthermore, in principle, there is no limitation on the area of ​​the adhered material and the adhesive layer, thus allowing for irradiation over a wide area in a single pass, which is also preferable.

[0175] <Uses>

[0176] The peeling method of this embodiment can be suitably used for peeling joints in various fields such as automobiles, mechanical parts, electrical products, and building materials (e.g., peeling joints between components, peeling joints between components and housings, etc.).

[0177] The peeling method of this embodiment is suitable for applications such as peeling off bonds that require recycling or reprocessing, or for use as a process material in the manufacturing processes of semiconductor process materials, glass masking materials, carrier tapes, and coating protective materials. Furthermore, it is particularly suitable for applications involving the peeling of expensive electronic components (e.g., liquid crystal panels, plasma panels, or organic EL panels) from their frames.

[0178] In particular, the stripping method of this embodiment is especially suitable for applications requiring optical transparency because of its high transmittance in the visible light region.

[0179] It should be noted that the application of the stripping method in this embodiment is not limited to the above-described applications.

[0180] Example

[0181] The present invention will be described in more detail below with examples and comparative examples, but the present invention is not limited to the following examples. It should be noted that, in the examples, "parts" refers to parts by mass.

[0182] (Preparation of the adhesive layer)

[0183] In a reaction vessel equipped with a condenser, a nitrogen inlet pipe, a thermometer, and a stirring device, 65 parts of butyl acrylate (BA), 15 parts of N-vinylpyrrolidone (NVP), 20 parts of 4-hydroxybutyl acrylate (4HBA) as monomer components, 0.1 parts of α-thioglycerol as a chain transfer agent, 122 parts of ethyl acetate as a polymerization solvent, and 0.2 parts of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator are added. Solution polymerization is carried out under a nitrogen atmosphere to obtain a solution containing acrylic polymers.

[0184] Two parts of dipentaerythritol hexaacrylate (DPHA), 0.2 parts of Omnirad (Irgacure) 184, and 0.1 parts of Takenate D110N (manufactured by Mitsui Chemicals Co., Ltd.) were added to the obtained solution containing acrylic polymers to obtain a base adhesive. Relative to 100 parts of this base adhesive, the aforementioned diammonium ionomer (Carlit Co., Ltd., trade name CIR-RL or CIR-FS265) or carbon black (Denka Black 100% Press, manufactured by Denka Co., Ltd.) as a near-infrared absorbing pigment was added as follows: The mixture was then degassed to obtain various acrylic adhesive compositions. It should be noted that "-" in Table 1 indicates the absence of this component.

[0185] Using a coating applicator, the obtained acrylic adhesive compositions are applied to a 38 μm thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "MRF#38") with a dry thickness of 50 μm, which has been peeled off on one side with silicone, to form a coating layer.

[0186] Next, the coating layer is placed in a dryer at 130°C and dried for 3 minutes. After being removed from the dryer, the coating layer is coated with a 38 μm thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "MRE#38") that has been peeled off with silicone on one side, so that the peeled side is the coating layer side, and various adhesive sheets with an adhesive layer thickness of 50 μm are obtained.

[0187] It should be noted that, through the same operation as described above, various adhesive sheets with an adhesive layer thickness of 150 μm were also prepared.

[0188] (Determination of minimum and maximum transmittance)

[0189] In this embodiment, the minimum transmittance in the near-infrared region with wavelengths of 800nm ​​to 2500nm and the maximum transmittance in the visible light region with wavelengths of 380nm to 780nm are measured in the following manner.

[0190] The release liner on one side of each adhesive sheet was peeled off and then rolled onto alkali-free glass (Corning Eagle XG, 45mm × 50mm × 0.7mm thickness) using a hand roller. The release liner on the other side was then peeled off and rolled onto another sheet of alkali-free glass using the same method. The resulting test pieces were then subjected to autoclaving at 50°C, 5 atmospheres, and for 15 minutes to ensure a tight bond between the adhesive layer and the glass. The test pieces were then irradiated with a high-pressure mercury lamp at a UVA conversion of 3000 mJ / cm². 2 The adhesive layer was post-cured under light to obtain the test sample. Then, the transmission spectrum of the test sample was measured using a UH-4150 UV-Vis-IR spectrophotometer (manufactured by Hitachi HighTech) with an integrating sphere unit in the wavelength range of 380 nm to 2500 nm and a step size of 1 nm, against an air background. Based on the obtained spectrum, the minimum transmittance (Tmin) in the near-infrared region (800 nm to 2500 nm) and the maximum transmittance (Tmax) in the visible light region (380 nm to 780 nm) were calculated.

[0191] The results are shown in Table 1. Additionally, Figures 2-4 The transmission spectra of the test samples using adhesive sheets with an adhesive layer thickness of 50 μm are shown in Table 1, representing a portion of the embodiments and comparative examples. Figure 2 This diagram illustrates the transmission spectrum when the aforementioned product, CIR-RL manufactured by Carlit Co., Ltd. of Japan, is used as a near-infrared absorbing pigment. Figure 3 This diagram illustrates the transmission spectrum when using the aforementioned Carlit Corporation of Japan, under the trade name CIR-FS265, as a near-infrared absorbing pigment. Figure 4 This is a graph showing the transmission spectrum when carbon black is used as a pigment.

[0192] (Using flash annealing to peel the adhered material from the adhesive layer)

[0193] The various adhesive sheets obtained above were cut into 100mm × 70mm pieces. The release liner on one side of each adhesive sheet was peeled off and then rolled onto a Corning Gorilla Glass 3 (120mm × 75mm × 0.7mm thickness) using a hand roller. Next, the release liner on the other side was peeled off and rolled onto another identical piece of Gorilla Glass using a hand roller. The resulting test pieces were then subjected to autoclaving at 50°C, 5 atmospheres, and 15 minutes to ensure a tight bond between the adhesive layer and the glass. The test pieces were then irradiated with a high-pressure mercury lamp at a UVA conversion of 3000 mJ / cm². 2 The light is used for post-curing of the adhesive.

[0194] For this test piece, an intermittent flash lamp irradiation device (NovaCentrix, PulseForge 1300X2 lamp) was used, with an irradiation range of 150mm × 75mm, a lamp height of 10mm, an applied voltage of 600V, a pulse width of 3000μs, and a light dose of 17000mJ / cm². 2 Under the condition of a lamp irradiation time (exposure time) of 0.003 seconds, one xenon flash irradiation was performed. The peak wavelength of the xenon flash was 880 nm. The state in which the glass and adhesive layer of the test piece were peeled off after flash irradiation was defined as the peelability under light irradiation ○, and the state in which they were not peeled off was defined as the peelability under light irradiation ×. The results are shown in Table 1.

[0195] [Table 1]

[0196]

[0197] According to the results in Table 1, in each embodiment, the pulse width for irradiating the adhesive layer was less than 1 second and the light irradiation dose was 1000 mJ / cm. 2 The above light and adhesive layers all meet the conditions of (1) the minimum transmittance is less than 75% and (2) the value obtained by dividing the maximum transmittance by the minimum transmittance is more than 1.15, thus resulting in good peelability when exposed to light.

[0198] On the other hand, Comparative Examples 1 to 3 did not meet the aforementioned conditions (1) and (2), and therefore their peelability under light irradiation was rated as ×.

[0199] In Comparative Examples 4 and 5, although the peelability under light irradiation showed good results, the transmittance of the adhesive sheet in the visible light region was poor due to the use of carbon black as a pigment.

[0200] Figure 5 (a) is a plan view (photograph) of the test samples used in Examples 1, 2, and Comparative Examples 4 and 5, which used adhesive sheets with an adhesive layer thickness of 50 μm. The test samples of Comparative Examples 4 and 5, which used carbon black, were blackened. In contrast, the test samples of Examples 1 and 2, although slightly colored, showed good light transmittance in the visible light region.

[0201] Figure 5 Example (b) shows an example where a printed paper surface is placed at the bottom of each test sample. See also Figure 5 (b) The differences in transmittance in the visible light region of the measured samples of the Examples and Comparative Examples are also obvious.

[0202] Various embodiments have been described above with reference to the accompanying drawings, but the present invention is certainly not limited to the examples described above. Those skilled in the art will obviously be able to conceive of various modifications or alterations within the scope of the claims, and these are naturally understood to fall within the technical scope of the present invention. Furthermore, the constituent elements of the above embodiments can be arbitrarily combined without departing from the spirit of the invention.

[0203] It should be noted that this application is based on Japanese patent application (Japanese Patent Application No. 2020-175486) filed on October 19, 2020, the contents of which are incorporated herein by reference.

[0204] Explanation of reference numerals in the attached figures

[0205] 1. Layered body

[0206] 12, 16 Adhesives

[0207] 14 Adhesive layer

Claims

1. A peeling method, characterized in that, by irradiating a laminate containing an adhesive layer and an adhesive material with light, the adhesive material is peeled off from the adhesive layer, wherein... The method includes irradiating the adhesive layer with a pulse width of less than 1 second and an irradiation dose of 1000 mJ / cm². 2 The above light-related processes, The light has a peak in the near-infrared region with wavelengths of 800 nm to 2500 nm. Regarding the adhesive layer, the minimum transmittance in the near-infrared region with a wavelength of 800 nm to 2500 nm and the maximum transmittance in the visible light region with a wavelength of 380 nm to 780 nm, measured by a test sample made by bonding an adhesive layer with a thickness of 1 μm to 5000 μm to one adhesive surface and an alkali-free glass with a thickness of 0.7 mm sandwiched between the adhesive layer, satisfy the following conditions (1) and (2): (1) The minimum transmittance is 75% or less; (2) The value obtained by dividing the maximum transmittance by the minimum transmittance is 1.15 or higher.

2. The peeling method as described in claim 1, wherein, The light was irradiated multiple times.

3. The peeling method as described in claim 1 or 2, wherein, The light irradiation intensity is 1000 mJ / cm². 2 ~100000mJ / cm 2 .

4. The peeling method as described in claim 1 or 2, wherein, The adhesive layer comprises an acrylic adhesive.

5. The peeling method as described in claim 1 or 2, wherein, The adhesive layer contains a near-infrared absorbing material.

6. The peeling method as described in claim 5, wherein, The near-infrared absorbing material is a near-infrared absorbing pigment.

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