Laminate, structure including the laminate and adherend, and method for peeling the structure

Abstract

To provide a novel laminate that is easily peelable from an adherend.SOLUTION: The laminate includes a base material whose light transmittance at a wavelength of 355 nm, measured in conformity with the visible light transmittance test of JIS A 5759:2016, is 50% or more, and an adhesive layer joined to the base material, the adhesive being characterized by containing (A) a polymerizable component, (B) a photopolymerization initiator, and (C) a UV absorber.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate, a structure including the laminate and an adherend, and a method for removing the structure. [Background technology]

[0002] In recent years, films with a specific structure (also called "decorative films") have been applied in place of paint to adherends such as the exterior bodywork of passenger cars, plastic products, metal products, and buildings, with the aim of providing color or a protective coating. Decorative films generally contain multiple layers, such as a surface protection layer, a design layer, and an adhesive layer.

[0003] Decorative films have the advantage that a specific laminated structure can be formed on the surface of an adherend more easily than by applying multiple coats of paint, and that it is easy to impart designs such as a three-dimensional effect and a sense of depth to the surface of the adherend. For example, Patent Document 1 discloses a laminated decorative film having a laminated structure in which a glossy layer, a transparent intermediate layer, a transparent uneven layer, and a transparent surface layer are laminated in this order.

[0004] Decorative films (laminates) are required to not peel off during use, but they must be removed when they are replaced (repaired). However, meeting these conflicting requirements has not been easy until now. Furthermore, peeling off a film without damaging the surface of the adherend is difficult, unlike peeling off paint. Previously, decorative films were peeled off by heating or by spraying water on the adhesive layer, but these methods did not solve the problems of leaving a thermal history on the adherend or of water seeping into the electronic components of the adherend.

[0005] Patent Document 2 discloses an automobile pillar containing a film, which is characterized by containing a polymer alloy and an ultraviolet absorber. The ultraviolet absorber is used to suppress discoloration of the decorative sheet.

[0006] However, the film described in Patent Document 2 cannot solve the problem of being difficult to remove from the automobile. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-101717 [Patent Document 2] Japanese Patent Publication No. 2023-063004 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above-mentioned conventional techniques, there is a need for a novel laminate that can be easily peeled from an adherend. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the present invention can provide the following aspects.

[0010] Aspect 1. A substrate having a light transmittance of 50% or more at a wavelength of 355 nm measured in accordance with the visible light transmittance test described in JIS A 5759:2016; a layer of adhesive bonded to the substrate; A laminate comprising: The adhesive (A) a polymerizable component; (B) a photopolymerization initiator; (C) UV absorber A laminate comprising:

[0011] Aspect 2. Aspect 1. The laminate of aspect 1, wherein component (A) includes a monomer having a single polymerizable group per molecule, a monomer having a plurality of polymerizable groups per molecule, or both.

[0012] Aspect 3. 3. The laminate of embodiment 2, wherein the polymerizable group comprises a (meth)acryloyl group.

[0013] Aspect 4. The laminate of embodiment 3, wherein the (A) component includes at least a difunctional (meth)acrylate monomer.

[0014] Aspect 5. The adhesive further comprises: (D) (meth)acrylate polymer 5. The laminate according to any one of aspects 1 to 4, comprising:

[0015] Aspect 6. A laminate according to any one of aspects 1 to 5, wherein the ratio of the thickness of the substrate divided by the thickness of the adhesive layer is in the range of 0.5 to 200.

[0016] Aspect 7. The laminate according to any one of aspects 1 to 6, which is a member for a moving body.

[0017] Aspect 8. A laminate according to any one of aspects 1 to 7; an adherend that is bonded to the adhesive layer of the laminate; A structure containing:

[0018] Aspect 9. 9. The structure of claim 8, wherein the adherend is a metal plate.

[0019] Aspect 10. A substrate having a light transmittance of 50% or more at a wavelength of 355 nm measured in accordance with the visible light transmittance test described in JIS A 5759:2016; a layer of adhesive bonded to the substrate; The adhesive layer is cured by irradiating it with light having a wavelength of 350 nm to 700 nm, and the adherend is joined to the adhesive layer. A method for peeling a layer of adhesive from an adherend in a laminate comprising: irradiating the adhesive layer with laser light having a wavelength of less than 385 nm through the substrate to peel the adhesive layer from the substrate; A method comprising: [Effects of the Invention]

[0020] The laminate according to the present invention has the remarkable effect of being easily adhered to and easily peeled from an adherend. DETAILED DESCRIPTION OF THE INVENTION

[0021] In this specification, unless otherwise specified, numerical ranges include the upper and lower limits. Furthermore, amounts and percentages in this specification are based on mass unless otherwise specified. In this specification, the term "sheet" also encompasses the concept of "film." Furthermore, the term "film" used in this specification has the same meaning as "sheet."

[0022] In this specification, polymerizable compounds such as (meth)acrylates refer to monomers, and those obtained by polymerization thereof are referred to as polymers. A monofunctional (meth)acrylate refers to a compound having one (meth)acryloyl group per molecule. A difunctional (meth)acrylate refers to a compound having two (meth)acryloyl groups per molecule, and is distinguished herein from other polyfunctional (meth)acrylates and monofunctional (meth)acrylates. In this specification, a polyfunctional (meth)acrylate refers to a compound having two or more (meth)acryloyl groups per molecule, although this may exclude bifunctional (meth)acrylates depending on the context. The polymerizable functional group in a polyfunctional (meth)acrylate may have only acryloyl groups, only methacryloyl groups, or both acryloyl and methacryloyl groups.

[0023] In one embodiment of the present invention, a laminate can be provided that includes a substrate and an adhesive layer bonded to the substrate. The laminate can be adhered to various adherends, such as the exterior or interior (e.g., metal plates such as steel plates) of mobile objects (e.g., automobiles, bicycles, ships, aircraft, etc.). In this specification, the term "steel plate" or "metal plate" encompasses coatings such as paint layers and protective layers. In other words, the laminate can be a product used as a mobile object component (e.g., an automobile component, such as a decorative component or protective component). In another embodiment, a structure including the laminate and an adherend can be provided.

[0024] [Base material] The substrate contained in this laminate has a light transmittance of 50% or more at a wavelength of 355 nm, measured in accordance with the visible light transmittance test described in JIS A 5759:2016. This is a necessary characteristic for proper irradiation of the adhesive layer with light. Since the wavelength of 355 nm is in the near-visible light region, it is understood that testing can be performed in accordance with the above-mentioned visible light transmittance test. Preferably, the light transmittance is 60% or more, more preferably 70% or more, and even more preferably 80% or more. The light transmittance can be measured using a spectrophotometer (e.g., Shimadzu Corporation's "SolidSpec-3700" spectrophotometer) in accordance with JIS R 3106:2019.

[0025] The substrate may be composed of a single layer (for example, a base film), or may have a structure including multiple layers (for example, a structure including two or more of a base film, a layer containing a pigment or the like for decoration, a design layer, and a protective layer).When the substrate includes multiple layers, it is sufficient that the overall light transmittance at a wavelength of 355 nm is 50% or more.

[0026] The substrate according to a preferred embodiment may have a light transmittance at a wavelength of 405 nm measured in accordance with the visible light transmittance test described in JIS A 5759: 2016 of 50% or more, more preferably 60% or more, even more preferably 70% or more, and even more preferably 80% or more. By combining the above characteristics related to the light transmittance at a wavelength of 355 nm and the characteristics related to the light transmittance at a wavelength of 405 nm, an effect is obtained that makes the peeling step easier to carry out.

[0027] The material for the substrate can be selected based on light transmittance and other physical properties, and examples include polycarbonate resin (PC), polymethyl methacrylate resin (PMMA), polypropylene resin (PP), polyvinyl chloride resin (PVC), and polyethylene terephthalate resin (PET), which can be molded to be transparent. For applications expected to be used outdoors, such as automobile exteriors, polycarbonate resin or polymethyl methacrylate resin is suitable in view of properties such as weather resistance, heat resistance, cold resistance, and insulation. The substrate may also be made of a combination of multiple materials. When the substrate includes multiple layers, the materials of each layer may be the same or different.

[0028] The thickness of the substrate can be selected arbitrarily, but is preferably in the range of 20 μm to 2000 μm, more preferably 50 μm to 1000 μm. When the thickness of the substrate is 20 μm or more, preferably 50 μm or more, the effect of improving the strength when attached to an adherend is obtained. When the thickness of the substrate is 2000 μm or less, preferably 1000 μm or less, the effect of improving the workability when attached to an adherend is obtained.

[0029] In a preferred embodiment, the substrate preferably contains as little UV absorber as possible, and more preferably contains no UV absorber at all, which improves the effect of facilitating peeling of the laminate from the adherend.

[0030] [glue] The present laminate comprises a substrate and an adhesive layer (adhesive layer) formed on the substrate for bonding to an adherend. The adhesive contains a polymerizable component, a photopolymerization initiator, and a UV absorber. The thickness of the adhesive layer can be selected arbitrarily, but is preferably in the range of 2 μm to 200 μm, more preferably 5 μm to 100 μm. When the thickness of the adhesive layer is 2 μm or more, preferably 5 μm or more, the effect of improving the base protection is obtained. When the thickness of the adhesive layer is 200 μm or less, preferably 100 μm or less, the effect of improving the flexibility of the laminate is obtained.

[0031] In a preferred embodiment, the ratio of the thickness of the substrate divided by the thickness of the adhesive layer may be in the range of 0.5 to 200, more preferably in the range of 1 to 100, and even more preferably in the range of 1 to 10. By adjusting the thickness ratio in this manner, the effect of improving stability when the laminate is adhered to an adherend can be obtained.

[0032] In one embodiment, a method can be provided in which the adhesive layer of the laminate is brought into contact with an adherend and irradiated with light having a wavelength of 350 nm to 700 nm to cure the adhesive layer, thereby bonding the laminate to the adherend.In another embodiment, a method can be provided in which a laminate bonded to an adherend as described above is irradiated with laser light having a wavelength of less than 385 nm through the substrate of the laminate to the adhesive layer, thereby peeling the adhesive layer from the substrate, thereby peeling the laminate from the adherend.

[0033] Because this laminate can be peeled using a UV laser as described above, it is also possible to peel it locally by laser irradiation. In other words, the peeling process can be performed locally without peeling the entire laminate at once, which has the effect of making the peeling process easier. Furthermore, peeling with a UV laser has the effect of minimizing damage to the adherend (especially automobiles).

[0034] [(A) Polymerizable component] The polymerizable component (A) contained in the adhesive is a molecule capable of forming a polymer through a polymerization reaction (radical polymerization, cationic polymerization, anionic polymerization, etc.). Component (A) may preferably contain a monomer having a single polymerizable group per molecule, a monomer having multiple polymerizable groups per molecule, or both. More preferably, component (A) may contain a compound having a (meth)acryloyl group, and even more preferably, a monofunctional (meth)acrylate, a bifunctional (meth)acrylate, a trifunctional or higher functional (meth)acrylate, or a mixture thereof. Note that component (A) does not include components (B) to (D), which will be described later, and is to be distinguished from them.

[0035] In a preferred embodiment, component (A) may contain at least a difunctional (meth)acrylate. More preferred examples of component (A) include a combination of a difunctional (meth)acrylate having an aromatic ring and an aliphatic difunctional (meth)acrylate, or a combination of a difunctional (meth)acrylate having an aromatic ring and a monofunctional (meth)acrylate. The content of the difunctional (meth)acrylate in component (A) is preferably in the range of 50 to 100% by mass, more preferably in the range of 70 to 100% by mass, even more preferably in the range of 90 to 100% by mass, and even more preferably 100% by mass.

[0036] The monofunctional (meth)acrylate that may be contained in component (A) is preferably a monofunctional (meth)acrylate having a molecular weight of 550 or less, and more preferably a monofunctional alkyl (meth)acrylate having an alkyl group. The alkyl group is preferably at least one selected from a linear alkyl group, a branched alkyl group, and an alicyclic alkyl group, and more preferably at least one selected from a linear alkyl group and a branched alkyl group. From the viewpoint of improving compatibility with other components, the (meth)acrylate component preferably has a long-chain, branched, or cyclic alkyl group, for example, a branched alkyl group or cycloalkyl group having 18 to 40 carbon atoms, more preferably 18 to 32 carbon atoms, such as an isostearyl group, an isotetracosanyl group (e.g., 2-decyl-1-tetradecanyl group), or an isotriacontanyl group (e.g., 2-tetradecyl-1-octadecanyl group). By using such long-chain, high-molecular-weight components with strong aliphatic hydrocarbon properties (and more preferably by increasing the aliphatic hydrocarbon properties of the entire system), it is possible to improve low volatility, chemical resistance, and / or heat resistance.

[0037] In some embodiments, the monofunctional (meth)acrylate may be an aromatic monofunctional (meth)acrylate, or may include a combination of an aliphatic monofunctional (meth)acrylate and an aromatic monofunctional (meth)acrylate, as described above.

[0038] Examples of monofunctional (meth)acrylates include stearyl (meth)acrylate, isostearyl (meth)acrylate, phenol EO-modified acrylate, nonylphenol EO-modified acrylate, 2-ethylhexyl EO-modified (meth)acrylate, behenyl (meth)acrylate, 2-decyl-1-tetradecanyl (meth)acrylate, 2-dodecyl-1-hexadecanyl (meth)acrylate, and 2-tetradecyl-1-octadecanyl (meth)acrylate.

[0039] Examples of the difunctional (meth)acrylate that may be contained in the component (A) include aromatic difunctional (meth)acrylates, alicyclic difunctional (meth)acrylates, and acyclic difunctional (meth)acrylates. From the viewpoint of obtaining a rigid structure, the component (A) preferably contains an aromatic difunctional (meth)acrylate, an alicyclic difunctional (meth)acrylate, or a mixture thereof.

[0040] Examples of aromatic difunctional (meth)acrylates include 9,9-bis[4-(2-hydroxyC1-C20 alkoxy)phenyl]fluorene di(meth)acrylate, C1-C20 alkoxylated bisphenol A di(meth)acrylate, EO-modified hydrogenated bisphenol A di(meth)acrylate, benzyl di(meth)acrylate, 1,3-bis(2-(meth)acryloyloxyC1-C20 alkyl)benzene, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, or structural isomers thereof. Di(meth)acrylates having a fused ring skeleton, such as a fluorene, indene, indecene, anthracene, azulene, or triphenylene skeleton, may be preferably included.

[0041] Examples of the alicyclic bifunctional (meth)acrylate include C1 to C20 alkoxylated hydrogenated bisphenol A di(meth)acrylate, 1,3-di(meth)acryloyloxyadamantane, tricyclo C10 to C20 alkane dimethanol di(meth)acrylate, dicyclo C5 to C20 di(meth)acrylate, and structural isomers thereof.

[0042] Examples of acyclic bifunctional (meth)acrylates include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, stearic acid-modified pentaerythritol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and caprolactone-modified hydroxypivalic acid neopentyl glycol di(meth)acrylate.

[0043] Examples of trifunctional (meth)acrylates that may be contained in component (A) include ethylene oxide isocyanurate modified tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tris[(meth)acryloyloxyethyl]isocyanurate.

[0044] Examples of tetrafunctional or higher polyfunctional (meth)acrylates that may be contained in component (A) include ditrimethylolpropane tetra(meth)acrylate, dimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol ethoxy tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0045] [(B) Photopolymerization initiator] The photopolymerization initiator, component (B) contained in the adhesive, is a substance that can initiate polymerization of component (A) upon irradiation with light. Component (B) is preferably a photoradical polymerization initiator. A photoradical polymerization initiator is a compound whose molecules are cleaved and split into two or more radicals upon irradiation with, for example, ultraviolet light or visible light (e.g., wavelength 350 to 700 nm, preferably 365 to 500 nm, more preferably 385 to 450 nm). Examples of the photoradical polymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one, 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-O-benzoyloxime, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime). Component (B) may contain one or more of these or a combination of two or more of them.

[0046] Preferably, component (B) may contain an acylphosphine oxide-based compound. Examples of preferred acylphosphine oxide-based compounds include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. The photoradical polymerization initiator preferably has high sensitivity and photofading resistance, resulting in excellent deep curing properties, and also has an absorption wavelength range for generating radicals that extends to a relatively long wavelength range. The preferred compounds described above have an absorption wavelength range up to approximately 440 nm, which is significantly different from the absorption wavelength range of the UV absorber described below. In other words, the degree of UV curing inhibition by the UV absorber is small, and radical polymerization can be initiated with light of a longer wavelength. Therefore, even in the presence of a UV absorber, radical polymerization can be initiated and cured efficiently at a relatively high speed.

[0047] In a preferred embodiment, the photoradical polymerization initiator can be selected based on absorbance. Specifically, the photoradical polymerization initiator can be selected from one or more compounds that satisfy one or more of the following conditions when dissolved at a concentration of 0.1% by mass in a solvent (e.g., acetonitrile, toluene, etc.) that does not have a maximum absorption in the wavelength region of 300 to 500 nm: absorbance of 0.5 or more at a wavelength of 365 nm, absorbance of 0.5 or more at a wavelength of 385 nm, and absorbance of 0.5 or more at a wavelength of 405 nm. Examples of compounds that satisfy such conditions include 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime), which has an absorbance of 0.5 or more at a wavelength of 365 nm when dissolved in acetonitrile as a solvent at a concentration of 0.1% by mass; 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-O-benzoyloxime, which has an absorbance of 0.5 or more at wavelengths of 365 nm and 385 nm; and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide, which have an absorbance of 0.5 or more at wavelengths of 365 nm, 385 nm, and 405 nm.

[0048] In addition, from the viewpoint of achieving both curability with a photoradical polymerization initiator and UV laser peeling, bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, which has an absorption wavelength range of 400 to 500 nm, can also be used as a photoradical polymerization initiator.

[0049] As the (B) photoradical polymerization initiator, one or more compounds selected from acylphosphine oxide compounds, titanocene compounds, and α-aminoalkylphenone compounds are preferred in terms of reaction rate, heat resistance after curing, and absorption characteristics in a wavelength range different from that of the UV absorber. In addition to the above, component (B) may also be an oxime ester compound.

[0050] Examples of the acylphosphine oxide compound include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc. Among these, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is particularly preferred.

[0051] Examples of titanocene compounds include bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium.

[0052] Examples of the α-aminoalkylphenone compounds include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one, and the like.

[0053] Examples of oxime ester compounds include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-O-benzoyloxime, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime), etc. Among these, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime) is preferred.

[0054] The amount of (B) photoradical polymerization initiator used is preferably 0.01 to 5 parts by mass, and more preferably 0.1 to 1 part by mass, per 100 parts by mass of component (A) in terms of reaction rate and heat resistance after curing. When component (B) is 0.01 part by mass or more, sufficient curability is obtained, and when it is 5 parts by mass or less, the effect of preventing heat resistance from being impaired is obtained.

[0055] [(C) UV absorber] The ultraviolet absorber (UV absorber), component (C) contained in the adhesive, is a compound whose molecules are cleaved and decomposed / vaporized by irradiation with ultraviolet or visible light laser, and this decomposition / vaporization occurs at the interface between the substrate and the adhesive, causing a loss of the adhesive strength that had been maintained up until just before the peeling process. The inclusion of component (C) in this adhesive has the effect of preventing damage to the adherend (substrate protection) when the laminate is peeled from the adherend by UV irradiation.

[0056] Component (C) is preferably a compound having one or more skeletons selected from the group consisting of a benzophenone skeleton, a triazole skeleton, a hydroxyphenyltriazine skeleton, and a phenol skeleton (preferably a hindered phenol skeleton). The reason why it is preferable to have such skeletons is that it provides a degree of overlap with the UV laser wavelength in the UV absorption wavelength range, UV absorption characteristics at the same wavelength, and heat resistance.

[0057] Examples of component (C) include 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis(butyloxyphenyl))-1,3,5-triazine, 2-[2-hydroxy-5-[2-((meth)acryloyloxy)ethyl]phenyl]-2H-benzotriazole, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl(meth)a One or more of the group consisting of acrylate, 2-(2-(meth)acryloyloxy,5-methyl)phenyl-2H-benzotriazole, 1,1-bis-[2-(meth)acryloyloxy,3-(2H-benzotriazol-2-yl),5-tertiaryoctyl]methane, and 2,2'-dihydroxy-4,4'-di(meth)acryloyloxybenzophenone are particularly preferred in terms of compatibility with the resin component, UV absorption characteristics, and heat resistance. Note that component (C), which has a polymerizable functional group such as a (meth)acryloyl group, is to be distinguished from component (A).

[0058] The amount of component (C) is preferably 0.01 to 10 parts by mass, more preferably 0.5 to 7 parts by mass, per 100 parts by mass of component (A). When the amount is 0.01 part by mass or more, a sufficient UV laser peeling speed is obtained, and when the amount is 10 parts by mass or less, compatibility with component (A) and heat resistance are not easily impaired.

[0059] [(D) (Meth)acrylate polymer] The adhesive may further contain a (meth)acrylate polymer as component (D). Component (D) refers to a polymer having a (meth)acryloyl group that is not a monomer of component (A). Component (D) is preferably a polyfunctional (meth)acrylate polymer. Examples of polyfunctional (meth)acrylate polymers include "ART CURE RA-341" and "APB-001" (the same product as RA-341A) manufactured by Negami Chemical Industrial Co., Ltd.

[0060] The amount of the component (D) may be, for example, in the range of 1 to 100 parts by mass per 100 parts by mass of the component (A).

[0061] The weight-average molecular weight in this specification is a value calculated as a standard polystyrene by gel permeation chromatography (GPC). Specifically, the weight-average molecular weight is determined by using tetrahydrofuran as a solvent, a GPC system (SC-8010 manufactured by Tosoh Corporation) under the following conditions, and creating a calibration curve using commercially available standard polystyrene.

[0062] Flow rate: 1.0ml / min Set temperature: 40℃ Column configuration: One Tosoh Corporation "TSK guardcolumn MP(xL)" 6.0 mm ID x 4.0 cm, and two Tosoh Corporation "TSK-GELMULTIPOREHXL-M" 7.8 mm ID x 30.0 cm (16,000 theoretical plates), for a total of three (total theoretical plate count: 32,000). Sample injection volume: 100 μl (sample solution concentration 1 mg / ml) Liquid delivery pressure: 39 kg / cm 2 Detector: RI detector (differential refractive index detector) [Example]

[0063] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to these.

[0064] Unless otherwise specified, the experiments were conducted at a temperature of 23°C and a humidity of 50%. The unit of material composition shown in the table is parts by mass.

[0065] [Table 1]

[0066] The following materials were used for the substrate. PC: Polycarbonate resin film (commercially available) PMMA: Polymethyl methacrylate resin film (commercially available)

[0067] The following was used as component (A) of the adhesive. HX-620: Caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate ("Kayarad HX-620" manufactured by Nippon Kayaku Co., Ltd., m + n ≒ 4) A-BPE-2: Ethoxylated bisphenol A diacrylate ("NK Ester A-BPE-2" manufactured by Shin-Nakamura Chemical Co., Ltd., in the structural formula below, R = -CHCHO-, m = n = 1) [ka]

[0068] A-BPEF-2: 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene diacrylate ("NK Ester A-BPEF-2" manufactured by Shin-Nakamura Chemical Co., Ltd.) HBPE-4: EO-modified hydrogenated bisphenol A diacrylate ("HBPE-4" manufactured by Daiichi Kogyo Seiyaku Co., Ltd., m + n ≒ 4) A-DOD-N: 1,10-decanediol diacrylate ("NK Ester A-DOD-N" manufactured by Shin-Nakamura Chemical Co., Ltd.) M-113: Nonylphenol EO-modified acrylate ("Aronix M-113" manufactured by Toagosei Co., Ltd.) ISTA: Isostearyl acrylate (Osaka Organic Chemical Industry Co., Ltd.)

[0069] The following was used as component (B) of the adhesive. Omnirad 819: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide ("Omnirad 819" manufactured by IGM Resins BV)

[0070] The following was used as component (C) of the adhesive. Tinuvin 460: 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis(butyloxyphenyl))-1,3,5-triazine ("Tinuvin 460" manufactured by BASF) RUVA-93: 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole (Otsuka Chemical Co., Ltd. "RUVA-93")

[0071] The following was used as component (D) of the adhesive. RA-341A: Multifunctional acrylate polymer (Negami Chemical Industrial Co., Ltd. "ART CURE RA-341A", the same product as the company's "APB-001", weight-average molecular weight 72,000)

[0072] [1. Light transmittance] The light transmittance of each substrate shown in the above table was measured at wavelengths of 355 nm and 405 nm using a spectrophotometer (Shimadzu Corporation, "SolidSpec-3700").

[0073] 2. Preparation of adhesive The adhesive materials shown in the table above were mixed at 80°C to obtain the adhesives as homogeneous mixtures.

[0074] [3. Creation of laminates and structures containing the laminates] The adhesive was applied to the substrate with an applicator to a thickness of 50 μm to obtain a laminate. The laminate was then attached to a steel plate (adherend) that had been subjected to epoxy electrodeposition coating, and the LED wavelength was 405 nm and the illuminance was 100 mW / cm. 2 The laminate was irradiated through the substrate for 50 seconds under the conditions of (a) to (c), thereby obtaining a structure in which the adhesive layer of the laminate was cured.

[0075] [4. UV laser irradiation] Using a UV laser processing machine ("OLMUV 355-20W-K" manufactured by OPI), the above structure was irradiated with a UV laser under the following conditions. Laser wavelength: 355nm Irradiation intensity: 2.8W Processing diameter: 50μm Frequency: 150kHz Scan speed: 22.5 m / sec

[0076] [5. Peel strength] A biaxial tensile test system (Shimadzu Corporation's "Autograph AG-Xplus") was used to conduct a peel test under the following conditions. The results are shown in the table above. Peeling direction: 90° Peeling speed: 5mm / sec Measurement width: 25mm Stroke: 80mm

[0077] [6. Presence or absence of dents] After the peel test, the adhesive was peeled from the substrate surface using gummed tape, and the presence or absence of dents was confirmed using a hybrid laser microscope ("OPTELICS HYBRID" manufactured by Lasertec Corporation). Samples in which peeling occurred between the adhesive and substrate surface during the peel test were observed as is. The results are shown in the table above.

[0078] [evaluation] In all of Examples 1 to 3, the peel interface was between the substrate and adhesive in the laminate both before and after UV laser irradiation. Furthermore, there was sufficient peel strength before UV laser irradiation, and the peel strength was significantly reduced after UV laser irradiation. Furthermore, no dents caused by the UV laser were observed. Therefore, it was confirmed that the performance of these examples was sufficiently high.

[0079] On the other hand, in Comparative Example 1, which had a low light transmittance at a wavelength of 355 nm, the peel strength did not decrease after UV laser irradiation, and the performance was poor.

[0080] In Comparative Example 2, which did not contain component (C), the peeling interface after UV laser irradiation was between the adhesive and the adherend, and dents were also generated by the UV laser.

Claims

1. A substrate having a light transmittance of 50% or more at a wavelength of 355 nm measured in accordance with the visible light transmittance test described in JIS A 5759:2016; a layer of adhesive bonded to the substrate; A laminate comprising: The adhesive (A) a polymerizable component; (B) a photopolymerization initiator; (C) a UV absorber; A laminate comprising:

2. 2. The laminate according to claim 1, wherein the component (A) comprises a monomer having a single polymerizable group per molecule, a monomer having a plurality of polymerizable groups per molecule, or both.

3. 3. The laminate according to claim 2, wherein the polymerizable group comprises a (meth)acryloyl group.

4. 4. The laminate according to claim 3, wherein the component (A) contains at least a difunctional (meth)acrylate monomer.

5. The adhesive further comprises: (D) (meth)acrylate polymer The laminate of claim 1 , comprising:

6. 2. The laminate according to claim 1, wherein the ratio of the thickness of the substrate divided by the thickness of the adhesive layer is in the range of 0.5 to 200.

7. 10. The laminate according to claim 1, which is a member for a moving body.

8. The laminate according to claim 1; an adherend that is bonded to the adhesive layer of the laminate; A structure containing:

9. 9. The structure according to claim 8, wherein the adherend is a metal plate.

10. A substrate having a light transmittance of 50% or more at a wavelength of 355 nm measured in accordance with the visible light transmittance test described in JIS A 5759:2016; a layer of adhesive bonded to the substrate; The adhesive layer is cured by irradiating it with light having a wavelength of 350 nm to 700 nm, and the adherend is joined to the adhesive layer. A method for peeling a layer of adhesive from an adherend in a laminate comprising: irradiating the adhesive layer with laser light having a wavelength of less than 385 nm through the substrate to peel the adhesive layer from the substrate; A method comprising:

Images