Adhesive sheet, laminate using said adhesive sheet, and method for producing same

Abstract

To provide an adhesive sheet which is usable without restrictions of light permeability and heat resistance of an adherend, and is excellent in following adhesion to a step of an adherend surface and a corrosion prevention effect of a metal surface included in the adherend surface, and a laminate using the adhesive sheet and a method for manufacturing the same.SOLUTION: An adhesive sheet has an adhesive layer which contains a photosetting resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than the polymerizable unsaturated double bond, a photopolymerization initiator (C), and one or two or more additives (D) having a function of capturing or neutralizing a halogen ion and / or an acid containing the halogen ion.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive sheet that can be suitably used for joining metal surfaces and members having uneven surfaces. [Background technology]

[0002] BACKGROUND ART Display devices such as televisions, smartphones, personal assistant devices (PADs), tablet computers, and car navigation systems are typically configured by combining components such as a display panel, a wiring board, a lighting device, and other electronic components.

[0003] Many components constituting a display device have uneven surfaces due to the placement of various components on a single component. Therefore, when bonding such a component with uneven surfaces to another component in the manufacture of a display device, a method such as applying an adhesive is used. Specifically, a commonly used method involves applying an adhesive to the bonding surface with unevenness to fill the surface unevenness, smoothing the adhesive-coated surface by squeegeeing the applied adhesive to remove thickness variations, and then bonding another component to the bonding surface (see, for example, Patent Document 1). However, this method requires management of the amount of adhesive applied and a time-consuming cleaning process after application. Therefore, a bonding method that replaces adhesives is needed to improve work efficiency.

[0004] In light of this background, the use of adhesive sheets with excellent conformability to uneven surfaces has been proposed in recent years in place of adhesives (see, for example, Patent Document 2). The adhesive sheet disclosed in Patent Document 2 is a photocurable adhesive sheet that is flexible before light irradiation, allowing it to conform to and come into contact with uneven surfaces of components, and by irradiating the sheet with light while it is attached to the components, the components can be firmly bonded together via the cured product of the adhesive sheet. Unlike when using adhesives, the method of bonding components using the adhesive sheet does not require application amount control or cleaning processes, simplifying the bonding process. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-136677 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-120773 Summary of the Invention [Problem to be solved by the invention]

[0006] The adhesive sheet disclosed in Patent Document 2 rapidly cures immediately after light irradiation, causing a loss of flexibility in a short period of time and resulting in poor adhesion to uneven surfaces. Therefore, when joining components using the above-mentioned adhesive sheet, it is necessary to first contact the components with the adhesive sheet before light irradiation to create a laminate, and then irradiate the laminate through the components with light to promote the curing reaction of the adhesive sheet. However, in order to irradiate the adhesive sheet with sufficient light to cause the curing reaction, the components must be light-transmitting. However, components with metal surfaces, such as metal components or components with metal parts mounted thereon, have low light transmittance or do not transmit light, making them difficult to join using the above-mentioned method.

[0007] Furthermore, when joining components using a thermosetting adhesive sheet, high temperature heating and pressure are required to fully promote the curing reaction, but this method is not applicable to joining components with low heat resistance, and the heating and pressure can cause thermal degradation, damage, and reduced functionality of the components and parts. Furthermore, there are problems such as distortion and deformation between the components due to differences in thermal expansion between the components, and cracks that occur between the adhesive sheet and the component, causing separation.

[0008] Furthermore, many of the components used in display devices are made of metal (metal components) or components on which metal parts are placed, and when an adhesive or adhesive sheet comes into contact with the surface of a metal component or a component on which a metal part is placed, the components contained in the adhesive corrode the metal, resulting in a deterioration in the functionality of the metal component or metal part. In particular, the higher the ability of the adhesive sheet or adhesive used to join components to conform to the unevenness of the adherend surface, the more corrosion of the metal surface included in the adherend surface is accelerated, resulting in a more pronounced deterioration in the functionality of the metal component or metal part.

[0009] The present disclosure has been made in consideration of the above problems, and aims to provide an adhesive sheet that can be used without being restricted by the light transmittance or heat resistance of the adherend, and that has excellent conformal adhesion to unevenness in the adherend surface and excellent corrosion prevention effect for metal surfaces included in the adherend surface, as well as a laminate using the adhesive sheet and a method for producing the same. [Means for solving the problem]

[0010] The present invention provides an adhesive sheet having an adhesive layer containing a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, a photopolymerization initiator (C), and one or more additives (D) having the function of capturing or neutralizing halogen ions and / or acids containing the halogen ions.

[0011] The present invention also provides a laminate having the above-mentioned adhesive sheet, a first member bonded to a first main surface of the adhesive sheet, and a second member bonded to a second main surface of the adhesive sheet.

[0012] The present invention also provides a method for manufacturing a laminate using the above-mentioned adhesive sheet, comprising the steps of [1] bonding a first member to a first main surface of the adhesive sheet, [2] bonding a second member to a second main surface of the adhesive sheet, and [3] curing the adhesive layer of the adhesive sheet, and further comprising the step of irradiating the first main surface or the second main surface of the adhesive sheet with active energy rays before the step [1] or between the steps [1] and [2], wherein at least one of the first member and the second member includes a metal surface on the surface that contacts the adhesive sheet. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an adhesive sheet that can be used without being restricted by the light transmittance or heat resistance of the adherend, and that has excellent conformal adhesion to unevenness in the adherend surface and excellent corrosion prevention effect for metal surfaces contained in the adherend surface, as well as a laminate using the adhesive sheet and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0014] The adhesive sheet of the present invention, as well as a laminate using the adhesive sheet and a method for producing the same, will be described below.

[0015] 1. Adhesive sheet The adhesive sheet of the present invention has an adhesive layer containing a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, a photopolymerization initiator (C), and one or more additives (D) having the function of capturing or neutralizing halogen ions and / or acids containing the halogen ions.

[0016] The adhesive sheet of the present invention can be used without being restricted by the light transmittance or heat resistance of the adherend, has high conformal adhesion to unevenness on the adherend surface, allowing for strong bonding, and can also inhibit corrosion of metal surfaces contained in the adherend surface.

[0017] More specifically, the adhesive sheet of the present invention contains the desired components described above in the adhesive layer, and the curing reaction proceeds gradually rather than rapidly after light irradiation, allowing the adhesive sheet to maintain flexibility even after light irradiation. This allows the adhesive sheet of the present invention to conform to and adhere to unevenness on the adherend surface as the adhesive layer cures, and furthermore, because it maintains appropriate flexibility even after curing, it can exhibit high adhesive strength to members.

[0018] Furthermore, since the adhesive sheet of the present invention has a slow curing reaction rate after light irradiation and the reaction proceeds gradually, by irradiating the adhesive sheet with light in advance when joining components to cause a curing reaction of the adhesive layer, the curing reaction continues even after the components to be joined are placed through the adhesive sheet, making it possible to firmly join the components together. As a result, the adhesive sheet of the present invention does not require light irradiation or heating and pressure at high temperatures to cause a curing reaction, as is the case with ordinary photocurable adhesive sheets and thermosetting adhesive sheets, and it becomes possible to easily join components together without being limited by the light transmittance or heat resistance of the components.

[0019] Furthermore, when an adhesive sheet comes into contact with the surface of a metal member such as a metal plate or a surface on which metal components such as metal wiring are placed, the metal surface included in the adherend surface is susceptible to corrosion by the acid generated from the adhesive layer. In particular, the higher the adhesive layer's ability to conform to unevenness on the adherend surface, the more susceptible the metal surface to corrosion. Examples of acids that cause metal corrosion include hydrogen halides generated by the reaction of hydrogen ions with halogen ions derived from halogen compounds such as chlorine and fluorine contained in the adhesive layer. Furthermore, when a cationic photopolymerization initiator is used as the photopolymerization initiator (C), examples include acids generated by the reaction of halogen compounds generated by the photopolymerization initiator (C) absorbing light and decomposing with hydrogen extracted from the solvent or the photopolymerization initiator (C) itself. In the presence of these acids, the metal surface included in the adherend surface is easily corroded by the acid. Corrosion is particularly likely to progress when the adhesive sheet is left in a humid and hot environment. Furthermore, contact with acid ionizes the metal included in the metal surface, making migration more likely.

[0020] In contrast, the adhesive sheet of the present invention uses additive (D) contained in the adhesive layer to capture or neutralize halogen ions and / or acids containing the halogen ions in the adhesive layer, thereby suppressing the generation and increase of acids and making metal corrosion less likely to occur even when the adhesive sheet adheres closely to a metal surface, thereby preventing deterioration in the function and performance of metal members and metal parts due to corrosion.

[0021] When the adhesive containing the additive (D) of the present invention is applied directly to the adherend surface, the additive (D) may not be uniformly dispersed on the adherend surface due to aggregation, etc., which may result in processing problems such as coating defects during application, making it impossible to obtain the desired adhesive strength, or the corrosion inhibition effect on the metal surface may be localized. In contrast, according to the present invention, by using a sheet with a pre-formed adhesive layer in which the additive (D) is uniformly dispersed, the occurrence of problems such as coating defects can be prevented, and when applied to the adherend surface, corrosion of the metal surface can be inhibited over the entire application surface, making it unnecessary to adjust the dispersion degree of the additive.

[0022] The members to be bonded using the adhesive sheet of the present invention may or may not include a metal surface on the adherend surface, but it is suitable for use in bonding members that include a metal surface on the adherend surface. This is because the adhesive layer contains the desired components, allowing it to exhibit high conformal adhesion to the adherend surface, and metal corrosion is unlikely to occur even when conformal adhesion to the metal surface occurs. Furthermore, the members to be bonded using the adhesive sheet of the present invention may or may not have steps on the adherend surface, but due to the high conformal adhesion of the adhesive sheet of the present invention, it is suitable for use in bonding members that have steps on the adherend surface.

[0023] Here, "including a metal surface on the adherend surface" and "including a metal surface on the surface in contact with the adhesive sheet" refer to an embodiment in which a portion of the adherend surface of the member to be attached to the adhesive sheet has a region containing a metal material, or an embodiment in which the entire adherend surface is a region containing a metal material. An embodiment in which a portion of the adherend surface (surface of the member) of the member has a region containing a metal material includes, for example, an embodiment in which a metal component is disposed on a portion of the adherend surface (surface of the member), specifically, an embodiment in which metal wiring is disposed in a pattern on the surface of the support, and the patterned metal wiring forms the metal surface. Furthermore, an embodiment in which the entire adherend surface is a region containing a metal material includes, for example, an embodiment in which metal components are disposed on the entire adherend surface (surface of the member) of the member, or an embodiment in which the member itself is formed of a metal material, specifically, an embodiment in which the adherend surface (surface of the member) of the member is covered with a metal layer, an embodiment in which the member is a metal substrate, etc.

[0024] The components bonded using the adhesive sheet of the present invention may or may not be optically transparent. In particular, the adhesive sheet of the present invention is suitable for bonding components with low optical transparency or optically opaque components. As described above, the adhesive sheet of the present invention has a slow curing reaction rate after light irradiation and can maintain flexibility even after light irradiation. Therefore, by irradiating the adhesive sheet with light before bonding the components, the curing reaction proceeds without irradiating the adhesive sheet with light through the components, thereby firmly bonding the components. The light transmittance of the component (adherend) is not particularly limited, but is preferably 90% or less in the wavelength range of 200 nm to 780 nm, and more preferably 80% or less, 70% or less, 60% or less, or 50% or less. An optically opaque component refers to a component with a light transmittance of 0% in the above wavelength range. The light transmittance of the adherend (component) is a value measured using an ultraviolet-visible spectrophotometer such as the V-570 manufactured by JASCO Corporation.

[0025] Furthermore, the members bonded using the adhesive sheet of the present invention may or may not have heat resistance. As described above, the adhesive sheet of the present invention undergoes a curing reaction upon light irradiation and remains flexible even after light irradiation, so the curing reaction proceeds without the need for high-temperature heating and pressure application. In addition, light irradiation and heat treatment may be used in combination as a curing method to promote the curing reaction. In this case, it is preferable that the members have heat resistance sufficient to withstand the heating temperature of the heat treatment performed after light irradiation to promote the curing reaction.

[0026] Each component of the adhesive sheet of the present invention will be described below.

[0027] (1) Adhesive layer The adhesive layer in the present invention contains a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, a photopolymerization initiator (C), and an additive (D) having the function of capturing or neutralizing halogen ions and / or acids containing the halogen ions.

[0028] The adhesive layer of the present invention contains a photocurable resin (A) and a thermoplastic resin (B), each of which has a polymerizable functional group other than a polymerizable unsaturated double bond. When the adhesive layer is irradiated with light, the polymerizable functional groups of the photocurable resin (A) and the thermoplastic resin (B) are activated, and curing proceeds in a state of enhanced reactivity. Therefore, the adhesive layer is prevented from undergoing a rapid curing reaction after light irradiation, allowing the curing reaction to proceed gradually. Furthermore, since the curing reaction after light irradiation proceeds gradually, the adhesive layer can maintain flexibility even after light irradiation, enabling the bonding of components. In other words, the adhesive layer of the present invention is a delayed-curing adhesive layer. Furthermore, the adhesive layer of the present invention can maintain appropriate flexibility even after curing.

[0029] The adhesive layer in the present invention is a layer composed of an adhesive composition containing a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, a photopolymerization initiator (C), and an additive (D) having the function of capturing or neutralizing halogen ions and / or acids containing the halogen ions. Specifically, the total amount of the adhesive layer refers to the total amount of adhesive composition constituting the adhesive layer, and the content in the adhesive layer refers to the content in the total amount of adhesive composition constituting the adhesive layer. The total amount of adhesive composition does not include the solvent.

[0030] <Photocurable resin (A)> The photocurable resin (A) has a polymerizable functional group other than a polymerizable unsaturated double bond. By including the photocurable resin (A), the adhesive layer of the present invention undergoes polymerization upon light irradiation due to the polymerizable functional group possessed by the photocurable resin (A), and the polymerization proceeds even in the dark or at low temperatures, making it possible to bond components without being limited by their light transmittance or heat resistance.

[0031] Examples of the photocurable resin (A) include photopolymerizable compounds such as photoradical polymerizable compounds, photocationic polymerizable compounds, and photoanionic polymerizable compounds. Among these, photocationic polymerizable compounds and / or photoanionic polymerizable compounds are preferred. In other words, the photocurable resin (A) preferably has a photocationic polymerizable functional group and / or a photoanionic polymerizable functional group as a polymerizable functional group other than a polymerizable unsaturated double bond. By including a polymerizable compound having such a functional group in the adhesive layer, the adhesive layer is less susceptible to oxygen inhibition during curing and facilitates continued reaction even after light irradiation. This allows bonding of components via the adhesive layer after light irradiation without being limited by the light transmittance or heat resistance of the components. Photocationic polymerizable compounds are particularly preferred because they have excellent reactivity after light irradiation and are likely to provide high bonding strength after curing. The photopolymerizable compounds may be used alone or in combination.

[0032] The photocationically polymerizable compound is not particularly limited as long as it has one or more photocationically polymerizable functional groups in one molecule. The photocationically polymerizable compound is preferably one having one or more photocationically polymerizable functional groups in one molecule, such as an epoxy group, an oxetanyl group, a hydroxyl group, a vinyl ether group, an episulfide group, an ethyleneimine group, or an oxazoline group. Among these, in order to obtain high curability and bondability after curing, the photocationically polymerizable compound is more preferably one having an epoxy group or an oxetanyl group, and particularly preferably one having an epoxy group.

[0033] As the photocationically polymerizable compound having an epoxy group, a compound having one or more epoxy groups in one molecule can be used. Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, polyhydroxynaphthalene type epoxy resin, isocyanate-modified epoxy resin, 10-(2,5-dihydroxyphenyl)-9,10-dihydro Examples of epoxy resins that can be used include 9-oxa-10-phosphaphenanthrene-10-oxide modified epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, hexanediol type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resin type epoxy resins, biphenyl-modified novolac type epoxy resins, trimethylolpropane type epoxy resins, alicyclic epoxy resins, acrylic resins having epoxy groups, polyurethane resins having epoxy groups, polyester resins having epoxy groups, and flexible epoxy resins.

[0034] Among these, it is preferable to use at least one of an alicyclic epoxy resin and a polyfunctional aliphatic epoxy resin, and it is more preferable to use an alicyclic epoxy resin, which has excellent photocationic polymerizability, and therefore can provide an adhesive sheet with excellent curing properties and can also impart a suitable elastic modulus to suppress deformation of the adhesive layer over time after bonding.

[0035] The epoxy resin may be modified. Blending or adding other resin components to the epoxy resin can increase the flexibility of the adhesive layer and improve its adhesive strength and bending strength. Examples of such modified resins include CTBN (carboxyl-terminated butadiene-acrylonitrile rubber)-modified epoxy resins; epoxy resins in which various rubbers, such as acrylic rubber, NBR, SBR, butyl rubber, or isoprene rubber, are dispersed in the resin; epoxy resins modified with the above-mentioned liquid rubbers; epoxy resins to which various resins, such as acrylic, urethane, urea, polyester, or styrene, have been added; chelate-modified epoxy resins; and polyol-modified epoxy resins.

[0036] On the other hand, examples of the photocationically polymerizable compound having an oxetanyl group include oxetane compounds such as 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 3-methyl-3-glycidyloxetane, 3-ethyl-3-glycidyloxetane, 3-methyl-3-hydroxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, and di{1-ethyl(3-oxetanyl)}methyl ether.

[0037] Furthermore, it is preferable to use a photocurable resin (a1) as the photocurable resin (A) whose temperature (Tg - Tan δ) at which the loss tangent after curing reaches its maximum value is 100°C or higher. This is because high heat resistance can be imparted to the adhesive sheet after curing. In particular, the temperature at which the loss tangent after curing of the photocurable resin (a1) reaches its maximum value is preferably 105°C or higher, 110°C or higher, or 115°C or higher, and the temperature is preferably 250°C or lower, more preferably 230°C or lower, or 200°C or lower. The temperature at which the loss tangent after curing of the photocurable resin (a1) reaches its maximum value (Tg - Tan δ) is a value measured at a frequency of 1.0 Hz using a dynamic viscoelasticity measuring device (manufactured by Rheometrics, product name: RSA-II) for a cured product obtained by curing the photocurable resin (a1) alone.

[0038] Examples of the photocurable resin (a1) having a temperature (Tg-Tanδ) of 100°C or higher at which the loss tangent after curing reaches a maximum value include epoxy resins that are solid at room temperature (hereinafter referred to as room-temperature solid epoxy resins). Room temperature refers to 25°C.

[0039] Specific examples of room temperature solid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, tetramethylbiphenyl type epoxy resins, polyhydroxynaphthalene type epoxy resins, isocyanate-modified epoxy resins, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide modified epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, hexanediol type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, phenol aralkyl type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resins, and biphenyl-modified novolac type epoxy resins.

[0040] Furthermore, when the photocurable resin (A) is an epoxy resin, it is preferable to use both an epoxy resin that is solid at room temperature and an epoxy resin that is liquid at room temperature (hereinafter referred to as a liquid-at-room-temperature epoxy resin). That is, it is preferable that the photocurable resin (A) contained in the adhesive layer in the present invention is one or more epoxy resins that are solid at room temperature and one or more epoxy resins that are liquid at room temperature. The combined use of an epoxy resin that is solid at room temperature and an epoxy resin that is liquid at room temperature facilitates processing into a sheet shape and imparts appropriate adhesiveness to the sheet before curing, making it easy to attach to an adherend. Furthermore, the combined use of an epoxy resin that is solid at room temperature and an epoxy resin that is liquid at room temperature can achieve excellent adhesive reliability after curing. Furthermore, the combined use of a polyfunctional epoxy resin, such as a novolac-type epoxy resin, as a solid-at-room-temperature epoxy resin, with an epoxy resin that is liquid at room temperature can achieve even better adhesiveness at high temperatures. The epoxy resin that is liquid at room temperature is not particularly limited as long as it is liquid at room temperature, but specific examples include trimethylolpropane epoxy resins, alicyclic epoxy resins, acrylic resins having epoxy groups, polyurethane resins having epoxy groups, polyester resins having epoxy groups, etc. Among these, alicyclic epoxy resins are preferred.

[0041] The proportion of photocurable resin (a1) in the photocurable resin (A) having a temperature (Tg-Tanδ) at which the loss tangent after curing reaches a maximum value of 100°C or higher is preferably within the range of 20% to 80% by mass, more preferably within the range of 30% to 70% by mass, more preferably within the range of 35% to 65% by mass, and even more preferably within the range of 40% to 65% by mass. Furthermore, when the photocurable resin (A) is an epoxy resin, the proportion of epoxy resin that is solid at room temperature relative to the total amount of epoxy resin is preferably within the range of 20% to 80% by mass, more preferably within the range of 30% to 70% by mass, more preferably within the range of 35% to 65% by mass, and even more preferably within the range of 40% to 65% by mass. This is because it can impart heat resistance to the cured sheet while also enabling curing to be completed in a relatively short time. The proportion of epoxy resin that is solid at room temperature relative to the total amount of epoxy resin can be calculated using the following formula: <expression> Proportion of epoxy resin solid at room temperature to the total amount of epoxy resin = (content of epoxy resin solid at room temperature [parts by mass] / total amount of epoxy resin [parts by mass]) x 100 [% by mass]

[0042] The photocurable resin (A) preferably has a weight-average molecular weight in the range of 100 to 5000, more preferably in the range of 150 to 3000, and even more preferably in the range of 200 to 2500. By setting the weight-average molecular weight of the photocurable resin (A) within the above range, the sheet shape before curing becomes more stable, improving handleability and enhancing conformal adhesion to the adherend surface. If the weight-average molecular weight of the photocurable resin (A) is too small, the cohesive strength of the adhesive layer before curing may be insufficient, leading to deterioration in handleability, such as bleeding of the adhesive layer over time. On the other hand, if the weight-average molecular weight of the photocurable resin (A) is too large, compatibility with the thermoplastic resin (B) may decrease, making it difficult for the reaction to proceed.

[0043] The weight average molecular weight of each component described in this specification is a value measured by gel permeation chromatography (GPC) using polystyrene standards under the following conditions. (conditions) Resin sample solution: 0.4% by mass tetrahydrofuran (THF) solution Measurement device model: HLC-8220GPC (manufactured by Tosoh Corporation) Column: TSKgel (Tosoh Corporation) Eluent: tetrahydrofuran (THF)

[0044] The content of the photocurable resin (A) in the adhesive layer of the present invention is preferably 10% by mass or more, 15% by mass or more, 20% by mass or more, or 25% by mass or more of the total amount of the adhesive layer, in other words, the total amount of the adhesive composition, and is preferably 90% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less. Specifically, the content of the photocurable resin (A) is preferably within the range of 10% to 90% by mass, preferably within the range of 15% to 85% by mass, preferably within the range of 20% to 80% by mass, or preferably within the range of 25% to 75% by mass of the total amount of the adhesive layer. By setting the content of the photocurable resin (A) in the adhesive layer of the present invention within the above range, the conformability to and adhesion to unevenness in the adherend surface can be further improved, and two members can be firmly bonded via the cured adhesive layer. If the content of the photocurable resin (A) is more than the above range, it may not be possible to process it into a sheet, whereas if it is less than the above range, the heat resistance of the adhesive layer after curing may deteriorate.

[0045] <Thermoplastic resin (B)> The thermoplastic resin (B) has a polymerizable functional group other than a polymerizable unsaturated double bond. By including the thermoplastic resin (B), the adhesive layer of the present invention can react with the photocurable resin (A), suppressing a rapid curing reaction after light irradiation and allowing the curing reaction to proceed gradually. This allows the adhesive layer of the present invention to retain flexibility even after light irradiation, and to adhere to unevenness in the adherend surfaces of the components after light irradiation, thereby enabling two components to be firmly bonded via the adhesive layer.

[0046] The polymerizable functional group other than the polymerizable unsaturated double bond possessed by the thermoplastic resin (B) is preferably a group selected from the group consisting of an isocyanate group, a hydroxyl group, an oxetanyl group, and an epoxy group. Using a thermoplastic resin (B) having at least one polymerizable functional group selected from the group consisting of an isocyanate group, a hydroxyl group, an oxetanyl group, and an epoxy group allows the thermoplastic resin (B) to react with the photocurable resin (A), suppressing a rapid curing reaction after light irradiation and allowing the curing reaction to proceed gradually. This allows the adhesive layer of the present invention to retain flexibility even after light irradiation, further improving its ability to conform to unevenness in the adherend surface, and enabling two members to be firmly bonded via the adhesive layer.

[0047] Examples of the thermoplastic resin (B) include polyester resins, polyurethane resins, acrylic resins, polyvinyl acetal resins, and epoxy resins (thermoplastic epoxy resins), each of which has a polymerizable functional group other than a polymerizable unsaturated double bond. These thermoplastic resins may be homopolymers or copolymers. These thermoplastic resins may be used alone or in combination of two or more.

[0048] The polyurethane resin having a polymerizable functional group other than a polymerizable unsaturated double bond is preferably a polyurethane resin (B') having at least one selected from the group consisting of an isocyanate group, a hydroxyl group, an oxetanyl group, and an epoxy group.

[0049] The polyurethane resin (B') can be obtained, for example, by reacting a polyol (b'1) with a polyisocyanate (b'2).

[0050] The polyol (b'1) preferably has a number average molecular weight in the range of 500 to 5000, and more preferably in the range of 1000 to 3000, in order to obtain an adhesive layer excellent in shape retention, coating workability, initial cohesive strength, etc. The number average molecular weight is a value measured under the following conditions.

[0051] The number average molecular weight described in this specification is a value measured by gel permeation chromatography (GPC) using polystyrene standards under the following conditions. (conditions) Resin sample solution: 0.4% by mass tetrahydrofuran (THF) solution Measurement device model: HLC-8220GPC (manufactured by Tosoh Corporation) Column: TSKgel (Tosoh Corporation) Eluent: tetrahydrofuran (THF)

[0052] As such polyol (b'1), for example, one or more members selected from the group consisting of polyester polyols, polycarbonate polyols and polyether polyols can be suitably used.

[0053] In particular, in the present invention, it is preferable to use one or more types of at least one of polyester polyols and polycarbonate polyols as the polyol (b'1), and it is preferable to use at least one or two types of polyester polyols. A more preferred example is to use two or more types of polyester polyols as the polyol (b'1). Another preferred example is to use one or two or more types of polyester polyols and one or two or more types of polycarbonate polyols as the polyol (b'1). Furthermore, another preferred example is to use one or two or more types of polyester polyols and one or two or more types of polyether polyols as the polyol (b'1). By using different types of polyester polyols in combination, or by using a polyester polyol in combination with a polyol other than the polyester polyol, the adhesive sheet of the present invention has a more stable sheet shape before curing, improving handleability, and also improving conformability and adhesion to unevenness in the adherend surface.

[0054] The proportion of the total amount of polyols selected from polyester polyols, polycarbonate polyols, and polyether polyols in the polyol (b'1) is preferably 20% by mass or more, more preferably 50% by mass or more, and particularly preferably 100% by mass, based on the total amount of the polyol (b'1). This is because the adhesive layer containing the polyurethane resin (B') can maintain a level of adhesion that allows application at room temperature, and can further improve the ability to conform to unevenness in the adherend surface.

[0055] When the polycarbonate polyol and the polyester polyol are used in combination, the mass ratio of the polycarbonate polyol to the polyester polyol (polycarbonate polyol / polyester polyol) is preferably in the range of 0.4 to 7.0, and more preferably in the range of 1.0 to 2.0. This is because a polyurethane resin having loss tangents (tan δ40 and tan δ60) within the desired range can be obtained, and an adhesive layer can be formed that is easy to handle before curing and has high conformability and adhesion to unevenness in the adherend surface. Furthermore, when the polyether polyol and the polyester polyol are used in combination, the mass ratio of the polyether polyol to the polyester polyol (polyether polyol / polyester polyol) can also be in the same range as above.

[0056] Examples of the polyester polyol that can be used include those obtained by an esterification reaction between a low-molecular-weight polyol and a polycarboxylic acid, polyesters obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymerized polyesters thereof.

[0057] Examples of the low molecular weight polyol that can be used include aliphatic alkylene glycols having a molecular weight of approximately 50 to 300, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and 1,3-butanediol, and cyclohexanedimethanol.

[0058] Furthermore, examples of the polycarboxylic acids that can be used in the production of the polyester polyols include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid, and anhydrides or esters thereof.

[0059] As the polyester polyol, it is preferable to use an aliphatic polyester polyol, and it is more preferable to use a linear aliphatic polyester polyol. This is because a polyurethane resin (B') having loss tangents (tanδ40 and tanδ60) within the desired range can be obtained, and an adhesive layer can be formed that is easy to handle before curing and has high conformability and adhesion to unevenness in the adherend surface. The linear aliphatic polyester polyol refers to a polyester polyol that does not have an alkyl group in the side chain.

[0060] Examples of the aliphatic polyester polyol include those obtained by reacting the aliphatic alkylene glycol with an aliphatic dicarboxylic acid, and it is preferable to use an aliphatic polyester polyol obtained by an esterification reaction of 1,6-hexanediol with adipic acid.

[0061] Furthermore, it is preferable to use an aromatic polyester polyol as the polyester polyol. This is because it can increase the elastic modulus of the polyurethane resin (B') and improve rigidity, making it possible to suppress bonding misalignment, warping, and deformation over time before and after curing of the adhesive layer. Examples of the aromatic polyester polyol include those obtained by reacting an aromatic polyol with an aliphatic or aromatic dicarboxylic acid, and for example, an aromatic polyester polyol obtained by reacting an ethylene oxide adduct of bisphenol A with phthalic acid and adipic acid is preferably used.

[0062] The polyester polyol may be an aliphatic polyester polyol alone, an aromatic polyester polyol alone, or a combination of an aliphatic polyester polyol and an aromatic polyester polyol. Among these, it is preferable to use an aliphatic polyester polyol and an aromatic polyester polyol together, that is, to use one or more aromatic polyester polyols and one or more aliphatic polyester polyols as the polyester polyol. This is because an adhesive layer containing a polyurethane resin (B') prepared using a combination of an aromatic polyester polyol and an aliphatic polyester polyol can achieve a good balance between hardness and softness before and after curing, exhibit high conformal adhesion to unevenness on the adherend surface, and suppress adhesion slippage, warping, and deformation of the adhesive layer over time. In order to achieve a good balance between the above-mentioned conflicting physical properties, the content ratio of the aromatic polyester polyol and the aliphatic polyester polyol (aromatic polyester polyol / aliphatic polyester polyol) is preferably within a range of 20 / 80 to 90 / 10 by mass, and more preferably within a range of 50 / 50 to 80 / 20.

[0063] The polyester polyol preferably has a number average molecular weight in the range of 1000 to 5000. This is because a polyurethane resin (B') having loss tangents (tan δ40 and tan δ60) within the desired range can be obtained, and an adhesive layer can be obtained that is easy to handle before curing and has better conformability and adhesion to unevenness in the adherend surface.

[0064] In particular, when a polyester polyol obtained by reacting an aliphatic diol such as 1,2-ethanediol or 1,4-butanediol with adipic acid is used as the polyester polyol, it is preferable to use one having a number average molecular weight in the range of 1100 to 2900. When a polyester polyol obtained by reacting 1,6-hexanediol with adipic acid is used, it is preferable to use one having a number average molecular weight in the range of 1100 to 5000. When a polyester polyol obtained by reacting 1,6-hexanediol with sebacic acid is used, it is preferable to use one having a number average molecular weight in the range of 1000 to 5000.

[0065] When the polyol (b'1) contains a polyester polyol and a polyol other than the polyester polyol, the polyester polyol can be used in an amount of 10% to 80% by mass, preferably 20% to 80% by mass, more preferably 30% to 70% by mass, and even more preferably 40% to 50% by mass, based on the total amount of the polyol (b'1). This is because the adhesive layer containing the polyurethane resin (B') can maintain a level of adhesion that allows application at room temperature, and can further improve conformal adhesion to unevenness on the adherend surface.

[0066] The polycarbonate polyol may be, for example, one obtained by reacting a carbonate ester and / or phosgene with a low-molecular-weight polyol. Examples of the carbonate ester that can be used include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, and diphenyl carbonate.

[0067] Examples of low molecular weight polyols that can react with the above carbonate esters and phosgene include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcinol, bisphenol A, bisphenol F, 4,4'-biphenol, and the like can be used.

[0068] As the polycarbonate polyol, it is preferable to use an aliphatic polycarbonate polyol or an alicyclic polycarbonate polyol.

[0069] It is preferable to use an aliphatic polycarbonate polyol obtained by reacting a dialkyl carbonate with one or more polyols selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol, because the adhesive layer containing the polyurethane resin (B') can have a level of adhesion that allows application at room temperature.

[0070] As the alicyclic polycarbonate polyol, it is preferable to use one obtained by reacting, for example, a dialkyl carbonate with a polyol containing one or more selected from the group consisting of cyclohexanedimethanol and its derivatives, because this allows the adhesive layer containing the polyurethane resin (B') to have a level of adhesion that allows application at room temperature and excellent initial cohesion.

[0071] The polycarbonate polyol preferably has a number average molecular weight in the range of 500 to 5000, and more preferably in the range of 800 to 3000. This is because a polyurethane resin (B') having loss tangents (tan δ40 and tan δ60) within the desired range can be obtained, and an adhesive layer can be obtained that is easy to handle before curing and has higher conformability and adhesion to unevenness in the adherend surface.

[0072] When the polyol (b'1) contains the polycarbonate polyol and a polyol other than the polycarbonate polyol, the polycarbonate polyol is preferably used in an amount of 20% to 80% by mass, more preferably 30% to 70% by mass, and more preferably 40% to 50% by mass, based on the total amount of the polyol (b'1). This is because the adhesive layer containing the polyurethane resin (B') can maintain a level of adhesion that allows application under light exposure at room temperature, and can further improve conformability and adhesion to unevenness on the adherend surface.

[0073] The polyether polyol may be, for example, one obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

[0074] Examples of the initiator that can be used include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, bisphenol A, glycerin, trimethylolethane, and trimethylolpropane.

[0075] Examples of the alkylene oxide that can be used include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran.

[0076] As the polyether polyol, it is preferable to use an aliphatic polyether polyol or a polyether polyol having an alicyclic structure.

[0077] As the polyether polyol, particularly usable are polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran, polytetramethylene glycol derivatives obtained by reacting tetrahydrofuran with alkyl-substituted tetrahydrofuran, polytetramethylene glycol derivatives obtained by copolymerizing neopentyl glycol with tetrahydrofuran, etc. Among these, it is preferable to use polytetramethylene glycol (PTMG) or polytetramethylene glycol derivatives (PTXG) as the polyether polyol, in order to ensure that the adhesive sheet including the adhesive layer maintains a level of adhesion possible at room temperature and improves excellent flexibility, durability (particularly hydrolysis resistance), etc.

[0078] In addition to the above-mentioned polyols, other polyols may be used as the polyol (b'1). Examples of the other polyols include acrylic polyols.

[0079] As the polyisocyanate (b'2), alicyclic polyisocyanates, aliphatic polyisocyanates, aromatic polyisocyanates, etc. can be used, and it is preferable to use alicyclic polyisocyanates.

[0080] Examples of the alicyclic polyisocyanate include isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 2,4- and / or 2,6-methylcyclohexane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexylene-1,2-dicarboxylate, and 2,5- and / or 2,6-norbornane diisocyanate, dimer acid diisocyanate, and bicycloheptane triisocyanate, which can be used alone or in combination of two or more.

[0081] Among the above-mentioned alicyclic polyisocyanates, it is preferable to use 4,4'-dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and 1,3-bis(isocyanatomethyl)cyclohexane (BICH), which have good reactivity with the above-mentioned polyol (b'1) and can be used to obtain an adhesive sheet having excellent heat resistance, light transmittance, etc.

[0082] A method for producing a polyurethane resin (B') having an isocyanate group by reacting the polyol (b'1) with the polyisocyanate (b'2) includes, for example, heating the polyol (b'1) charged into a reaction vessel under normal or reduced pressure conditions to remove moisture, and then supplying the polyisocyanate (b'2) all at once or in portions to cause the reaction.

[0083] The reaction of the polyol (b'1) with the polyisocyanate (b'2) is preferably carried out in such a manner that the equivalent ratio of the isocyanate groups of the polyisocyanate (b'2) to the hydroxyl groups of the polyol (b'1) (hereinafter referred to as the [NCO / OH equivalent ratio]) is in the range of 1.1 to 20.0, more preferably in the range of 1.1 to 13.0, even more preferably in the range of 1.1 to 5.0, and particularly preferably in the range of 1.5 to 3.0.

[0084] The reaction conditions (temperature, time, etc.) between the polyol (b'1) and the polyisocyanate (b'2) may be appropriately set taking into consideration various factors such as safety, quality, and cost, and are not particularly limited. For example, the reaction temperature is preferably in the range of 70 to 120°C, and the reaction time is preferably in the range of 30 minutes to 5 hours.

[0085] When the polyol (b'1) and the polyisocyanate (b'2) are reacted, a catalyst such as a tertiary amine catalyst or an organometallic catalyst may be used as needed.

[0086] The reaction between the polyol (b'1) and the polyisocyanate (b'2) may be carried out in a solvent-free environment or in the presence of an organic solvent. Examples of the organic solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone; ether ester solvents such as methyl cellosolve acetate and butyl cellosolve acetate; aromatic hydrocarbon solvents such as toluene and xylene; and amide solvents such as dimethylformamide and dimethylacetamide. These solvents may be used alone or in combination. The organic solvent may be removed during or after the production of the polyurethane resin (B') by a suitable method such as heating under reduced pressure or drying at normal pressure.

[0087] The polyurethane resin (B') having an isocyanate group may be, for example, a polyurethane resin (B'1) having an isocyanate group obtained by reacting a polyol (b'1) with a polyisocyanate (b'2). The details (types, blending, etc.) of the polyol (b'1) and polyisocyanate (b'2) used in preparing the polyurethane resin (B') having an isocyanate group may be the same as those of the polyol (b'1) and polyisocyanate (b'2) described above.

[0088] The polyurethane resin (B') having hydroxyl groups may be, for example, a polyurethane resin (B'2) having hydroxyl groups obtained by reacting a polyol (b'1) with a polyisocyanate (b'2). The details (types, blending, etc.) of the polyol (b'1) and polyisocyanate (b'2) used in preparing the polyurethane resin (B') having hydroxyl groups may be the same as those of the polyol (b'1) and polyisocyanate (b'2) described above.

[0089] Examples of the polyurethane resin (B') having an oxetanyl group or an epoxy group include 1) a polyurethane (B'1) having an isocyanate group; 2) a monomer (B") having a functional group (b"1) capable of reacting with an isocyanate group, an oxetanyl group or an epoxy group, and a polymerizable functional group (b"2) other than one or more polymerizable unsaturated double bonds; It is possible to use a polyurethane resin (B'3) obtained by reacting the following.

[0090] As the functional group (b"1) capable of reacting with the isocyanate group, for example, a hydroxyl group, an amino group, a carboxyl group, a mercapto group, etc. can be used, and among these, it is preferable to use a hydroxyl group or an amino group.

[0091] The polymerizable functional group (b"2) other than the polymerizable unsaturated double bond refers to a functional group other than a so-called radically polymerizable functional group, such as a cationic polymerizable functional group or an anionic polymerizable functional group, for example, an epoxy group, an oxetanyl group, an ethylene sulfide group, etc.

[0092] The monomer (B″) is not particularly limited as long as it has a functional group (b″1) and a polymerizable functional group (b″2), and examples thereof include 3-ethyl-3-(4-hydroxybutyl)oxymethyl-oxetane, 3-hydroxymethyl-3-ethyloxetane, 2-hydroxymethyloxetane, and 3-hydroxyoxetane.

[0093] The monomer (B") is preferably used in an amount of 5 to 20 parts by mass, more preferably 5 to 15 parts by mass, per 100 parts by mass of the polyurethane resin (B').

[0094] More specifically, the monomer (B") can be used in an amount that can supply functional groups reactive with the isocyanate groups, preferably more than 50 mol % and not more than 100 mol %, more preferably 60 mol % to 100 mol %, and even more preferably 80 mol % to 100 mol %, relative to the number of moles of isocyanate groups in the polyurethane resin (B'). This makes it possible to obtain a polyurethane resin that has appropriate flexibility, fast curing properties, shape retention after application to a substrate, mechanical strength, durability (particularly hydrolysis resistance), conformability to the adherend surface, and other excellent properties.

[0095] When reacting the urethane resin (B') with the monomer (B"), a urethanization catalyst can be used, if necessary. The urethanization catalyst can be added as needed at any stage of the urethanization reaction. The urethanization reaction is preferably carried out until the isocyanate group content (%) becomes substantially constant. As the urethanization catalyst, for example, nitrogen-containing compounds such as triethylamine, triethylenediamine, and N-methylmorpholine; organometallic salts such as potassium acetate, zinc stearate, and stannous octoate; and organometallic compounds such as dibutyltin dilaurate can be used.

[0096] Furthermore, epoxy resins having a polymerizable functional group other than a polymerizable unsaturated double bond include polymers or copolymers of epoxy compounds having a linear structure, and copolymers of epoxy compounds and monomers polymerizable with the epoxy compounds having a linear structure. Specific examples include bisphenol A epoxy resins, bisphenol fluorene epoxy resins, cresol novolac epoxy resins, phenol novolac epoxy resins, cyclic aliphatic epoxy resins, long-chain aliphatic epoxy resins, glycidyl ester epoxy resins, and glycidyl amine epoxy resins, with bisphenol A epoxy resins and bisphenol fluorene epoxy resins being preferred.

[0097] In particular, the adhesive layer of the present invention preferably contains, as the thermoplastic resin (B), one or more resins selected from the group consisting of polyurethane resins, acrylic resins, and epoxy resins, each having a polymerizable functional group other than a polymerizable unsaturated double bond. It is preferable to contain at least one or more polyurethane resins having a polymerizable functional group other than a polymerizable unsaturated double bond. Using a polyurethane resin having a polymerizable functional group other than a polymerizable unsaturated double bond as the thermoplastic resin (B) can suppress a rapid curing reaction after light irradiation and allow the curing reaction to proceed gradually, thereby maintaining the flexibility required for bonding even after light irradiation. This allows the adhesive layer of the present invention to conform to and adhere to uneven surfaces of the components to be bonded after light irradiation, making it possible to firmly bond the components together via the adhesive layer.

[0098] The melting point of the thermoplastic resin (B) is preferably in the range of 30° C. to 120° C., more preferably in the range of 35° C. to 100° C., and even more preferably in the range of 40° C. to 80° C. By using a thermoplastic resin (B) having a melting point within the above range, the adhesive sheet of the present invention has a more stable sheet shape before curing, improving handleability, and also improving its ability to conform to unevenness in the adherend surface.

[0099] The melting point of the thermoplastic resin (B) refers to the temperature at which the maximum exothermic peak (exothermic peak top) is observed when the sample is heated from 20°C to 150°C at a heating rate of 10°C / min using differential scanning calorimetry (DSC), held for 1 minute, cooled to -10°C at a cooling rate of 10°C / min, held for 10 minutes, and then measured again at a heating rate of 10°C / min.

[0100] The thermoplastic resin (B) preferably has a weight-average molecular weight in the range of 5,500 to 2,000,000, more preferably in the range of 5,500 to 1,000,000, and even more preferably in the range of 5,500 to 800,000. By setting the weight-average molecular weight of the thermoplastic resin (B) within the above range, the sheet shape before curing becomes more stable, improving handleability and enhancing the ability to conform to unevenness in the adherend surface. If the weight-average molecular weight of the thermoplastic resin (B) is too small, the cohesive strength of the adhesive layer before curing may be insufficient, which may lead to poor handleability, such as bleeding of the adhesive layer over time. On the other hand, if the weight-average molecular weight of the thermoplastic resin (B) is too large, compatibility with the photocurable resin (A) may decrease, making it difficult for the reaction to proceed.

[0101] The content of the thermoplastic resin (B) in the adhesive layer of the present invention is preferably 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, or 30% by mass or more, and preferably 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less, based on the total amount of the adhesive layer, i.e., the total amount of the adhesive composition. Specifically, the content is preferably within the range of 5% to 80% by mass, more preferably within the range of 10% to 60% by mass, and more preferably within the range of 20% to 50% by mass. By keeping the content of the thermoplastic resin (B) in the adhesive layer within the above range, flexibility can be imparted that ensures conformability to the adherend even after light irradiation. Note that if the content of the thermoplastic resin (B) is higher than the above range, the heat resistance of the cured product may be deteriorated. On the other hand, if the content is lower than the above range, the proportion of high-molecular-weight components in the entire adhesive layer is reduced, and it may be impossible to process it into a sheet.

[0102] The content ratio of the thermoplastic resin (B) to the content of the photocurable resin (A) ([content of thermoplastic resin (B) / content of photocurable resin (A)]) is preferably within a range of 0.1 to 10 by mass, preferably within a range of 0.15 to 2, preferably within a range of 0.2 to 1.7, preferably within a range of 0.3 to 1.5, and preferably within a range of 0.4 to 0.8. By setting the content ratio of the thermoplastic resin (B) to the content of the photocurable resin (A) within the above range, flexibility can be imparted that ensures conformability to the adherend even after light irradiation, and heat resistance can be imparted to the adhesive layer after curing. In particular, by setting the ratio of the thermoplastic resin (B) lower than the photocurable resin (A), excellent adhesive reliability can be obtained after curing, and excellent adhesiveness at high temperatures can also be obtained.

[0103] <Photopolymerization initiator (C)> The adhesive layer of the present invention contains one or more photopolymerization initiators (C), which promotes reactivity after irradiation with active energy rays and improves bonding strength after curing. Furthermore, the adhesive layer contains a photopolymerization initiator that is activated by light and whose reaction proceeds. Therefore, the reaction continues even after irradiation with active energy rays is stopped, allowing the reaction to proceed even in dark places or at low temperatures, resulting in a good curing reaction. This allows for high bonding strength to be achieved without damaging the components to be bonded, without causing distortion between the components that could deform the components, or without causing cracks between the adhesive sheet and the components.

[0104] The photopolymerization initiator (C) is not particularly limited as long as it is activated by light. Examples of the photopolymerization initiator (C) include a photoradical polymerization initiator, a photocationic polymerization initiator, and a photoanionic polymerization initiator. Among them, at least one of a photocationic polymerization initiator and a photoanionic polymerization initiator is preferred, and a photocationic polymerization initiator is more preferred because it can suitably adjust the polymerization by dark reaction.

[0105] The photocationic polymerization initiator is not particularly limited as long as it can induce a ring-opening reaction of a cationically polymerizable functional group by light of the wavelength used. Among them, a compound that induces a ring-opening reaction of a cationically polymerizable functional group by light of a wavelength of 300 nm to 370 nm and is inactive in the wavelength region exceeding 370 nm is preferably used. Examples of such photocationic polymerization initiators include onium salts such as aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts.

[0106] Specific examples of onium salts include Optomer SP-150, Optomer SP-170, Optomer SP-171 (all manufactured by ADEKA Corporation), UVE-1014 (manufactured by General Electronics Corporation), OMNICAT250, OMNICAT270 (all manufactured by IGM Resin), IRGACURE290 (manufactured by BASF), San-Aid SI-60L, San-Aid SI-80L, San-Aid SI-100L (all manufactured by Sanshin Chemical Industry Co., Ltd.), CPI-100P, CPI-101A, CPI-200K (all manufactured by San-Apro Ltd.), and the like.

[0107] The cationic photopolymerization initiator may be used alone or in combination of two or more. Furthermore, two or more cationic photopolymerization initiators with different effective active wavelengths may be used to perform two-stage curing.

[0108] The above cationic photopolymerization initiator may be used in combination with a sensitizer such as an anthracene-based or thioxanthone-based sensitizer, if necessary.

[0109] The cationic photopolymerization initiator is preferably contained in the range of 0.001% by mass to 30% by mass, more preferably 0.01% by mass to 20% by mass, and even more preferably 0.1% by mass to 10% by mass of the total amount of the adhesive layer, in other words, the total amount of the adhesive composition forming the adhesive layer. If the blending ratio of the cationic photopolymerization initiator is too low, the curing required to achieve high bondability will be insufficient, while if the blending ratio is too high, the curing property will improve but the curing reaction after light irradiation will proceed too quickly, making it difficult to sufficiently follow and adhere to unevenness in the adherend surfaces and to firmly bond the members together.

[0110] <Additives (D)> The adhesive layer in the present invention contains an additive (D) that has the function of capturing or neutralizing halogen ions and / or acids containing halogen ions. In the present invention, the additive (D) that has the function of capturing halogen ions can be referred to as a halogen ion scavenger, and the additive (D) that has the function of neutralizing acids containing halogen ions can be referred to as a halogen acid neutralizer. The additive (D) can be used alone or in combination of two or more.

[0111] The additive (D) has the function of capturing halogen ions and / or neutralizing acids containing the halogen ions, and it is particularly preferred that the additive (D) has the function of capturing or neutralizing chloride ions and / or hydrogen chloride.

[0112] Examples of the additive (D) having the function of capturing or neutralizing halogen ions and / or acids containing the halogen ions include ion scavengers, basic solids, and amphoteric metal oxides.

[0113] The ion trapping agent may be used alone or in combination of two or more. The ion trapping agent is sufficient as long as it has the function of trapping at least halogen ions, and is preferably a compound selected from the group consisting of anion trapping agents that trap anions and amphoteric ion trapping agents that trap both cations and anions. Among them, amphoteric ion trapping agents are preferred because they can further enhance the corrosion inhibition effect on metal surfaces by simultaneously trapping halogen ions, which are anions, and metal ions, which are cations.

[0114] The ion trapping agent may be an inorganic ion trapping agent made of an inorganic compound, an organic ion trapping agent made of an organic compound, or a combination of an inorganic ion trapping agent and an organic ion trapping agent. Among these, inorganic ion trapping agents are preferred. This is because inorganic ion trapping agents have higher heat resistance than organic ion trapping agents and have excellent dispersibility, allowing them to be uniformly dispersed in the adhesive layer, making it possible to suppress the occurrence of metal corrosion over the entire contact area with the metal surface included in the adherend surface.

[0115] The ion trapping agent preferably contains one or more compounds selected from the group consisting of inorganic anion trapping agents, which are inorganic ion trapping agents that trap anions, and inorganic amphoteric ion trapping agents, which are inorganic ion trapping agents that trap both cations and anions, because they can be uniformly dispersed in the adhesive layer and efficiently trap halogen ions throughout the layer. Among these, it is preferable to contain one or more inorganic amphoteric ion trapping agents, because they can trap metal ions in addition to the above-mentioned effects.

[0116] Specific examples of inorganic anion scavengers and inorganic amphoteric ion scavengers include inorganic compounds containing one or more metal atoms selected from the group consisting of antimony, bismuth, zirconium, titanium, tin, magnesium, and aluminum. Among these, inorganic compounds containing the three metal atoms of zirconium, aluminum, and magnesium are preferred. Commercially available inorganic anion scavengers include, for example, "IXE-700F" manufactured by Toagosei Co., Ltd., and commercially available inorganic amphoteric ion scavengers include, for example, "IXEPLAS-A1," "IXEPLAS-A2," "IXEPLAS-A3," and "IXEPLAS-B1" manufactured by Toagosei Co., Ltd.

[0117] In addition, a cation scavenger capable of capturing metal ions may be used in combination with the anion scavenger and both ion scavenger. This is because it can prevent the metal contained in the metal surface from ionizing and migrating. Examples of the cation scavenger include triazine thiol compounds and bisphenol-based reducing agents. Examples of the bisphenol-based reducing agents include 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol) and 4,4'-thio-bis-(3-methyl-6-tert-butylphenol).

[0118] The basic solid may be used alone or in combination of two or more kinds. The basic solid may be any compound capable of neutralizing an acid containing a halogen ion, and may be an inorganic basic solid or an organic basic solid.

[0119] Specific examples of inorganic basic solids include inorganic solids selected from the group consisting of inorganic salts, metal oxides, metal hydroxides, metal sulfides, metal nitrides, and clay minerals, and these solids whose surfaces have been treated with a basic agent.

[0120] Here, basic treatment refers to a treatment in which an inorganic solid selected from the group consisting of metal oxides, metal hydroxides, metal sulfides, metal nitrides, and clay minerals is used as a core compound, and a silane coupling agent having a basic group or a nitrogen compound such as hexamethyldisilazane is reacted with or adsorbed onto the core compound to make the surface of the core compound basic. Examples of basic groups include organic amino groups and hydroxyl groups. The treatment is not limited to these, as long as it can make the surface of the core compound basic. Examples of inorganic solids whose surfaces have been basic-treated include inorganic basic solids whose surfaces have been silanized.

[0121] Examples of inorganic salts used as basic solids include calcium carbonate, barium carbonate, magnesium carbonate, lithium carbonate, strontium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, potassium bicarbonate, calcium bicarbonate, magnesium bicarbonate, zinc carbonate, calcium phosphate, magnesium phosphate, sodium phosphate, potassium phosphate, barium phosphate, sodium citrate, potassium citrate, calcium citrate, magnesium citrate, magnesium oxalate, sodium oxalate, potassium oxalate, sodium tartrate, and potassium tartrate.

[0122] Examples of metal oxides (basic metal oxides) used as basic solids include basic glass beads, basic alumina (activated alumina), basic zeolite, basic titanium oxide, basic zinc oxide, basic lead oxide, basic silica, basic tin oxide, basic zirconium oxide, basic magnesium oxide, and basic calcium oxide.

[0123] An example of a metal sulfide (basic metal sulfide) used as a basic solid is basic zinc sulfide.

[0124] An example of a metal nitride (basic metal nitride) used as a basic solid is basic titanium nitride.

[0125] Examples of clay minerals (basic clay minerals) used as basic solids include basic talc and basic mica.

[0126] An example of a metal hydroxide (basic metal hydroxide) used as a basic solid is basic magnesium hydroxide.

[0127] Basic glass beads, basic alumina, basic titanium oxide, basic zinc oxide, basic silica, basic tin oxide, basic zirconium oxide, basic titanium nitride, basic zinc sulfide, and the like can be those in which basic functional groups have been introduced onto the surface of a core compound such as a metal oxide, metal nitride, or metal sulfide, which is a precursor, by basic treatment, for example.

[0128] Examples of organic basic solids include polymers having a basic functional group, organic polymer beads whose surfaces have been subjected to coupling treatment with a compound containing a basic functional group, and organic polymer beads coated with polymers having a basic functional group. Examples of basic functional groups include organic amino groups, nitrogen atom-containing heterocyclic groups, and weak acid-strong base salt functional groups. Polymers having a basic functional group are synthesized by polymerizing a monomer having a basic functional group. Organic basic solids can be synthesized by known methods, or commercially available products can be used.

[0129] Amphoteric metal oxides are compounds that can react with both acids and bases, and may be used alone or in combination of two or more. The amphoteric metal oxide may be any compound capable of neutralizing an acid containing a halogen ion, and examples thereof include alumina, zinc oxide, tin oxide, and lead oxide. The alumina, zinc oxide, tin oxide, and lead oxide in the amphoteric metal oxides are distinguished from the basic alumina (activated alumina), basic zinc oxide, basic tin oxide, and basic lead oxide in the basic metal oxides described above, in that they do not have a basic functional group introduced therein.

[0130] In particular, the adhesive layer in the present invention preferably contains, as additive (D), one or more compounds selected from the group consisting of inorganic ion scavengers and basic solids. This is because these compounds can exhibit high halogen ion scavenging ability or acid neutralizing ability even in small amounts. In particular, it is preferable to contain one or more inorganic ion scavengers. This is because, compared with basic solids, inorganic ion scavengers are more likely to provide acid corrosion resistance in small amounts.

[0131] When an inorganic ion scavenger is contained as additive (D), for the reasons described above, the inorganic ion scavenger is preferably a compound selected from the group consisting of inorganic anion scavengers and inorganic amphoteric ion scavengers, and more preferably an inorganic amphoteric ion scavengers.

[0132] Furthermore, when a basic solid is contained as additive (D), the basic solid is preferably an inorganic salt, because it can exhibit high halogen ion capturing ability or acid neutralizing ability without introducing basic functional groups onto the surface. Among inorganic salts, calcium carbonate is preferably used.

[0133] The additive (D) can have various shapes, such as particulate, needle-like, or flake-like, but particulate form is preferred from the viewpoint of uniform dispersion. When the additive (D) is particulate, the smaller the average particle size of the additive (D), the more preferable. Specifically, it is preferably 0.01 μm to 500 μm, more preferably 0.02 μm to 400 μm, more preferably 0.05 μm to 300 μm, and more preferably 0.5 μm to 200 μm. When the additive is in the form of primary particles without aggregation, the average particle size of the primary particles is preferably within the above range. On the other hand, when the additive is in the form of secondary particles due to aggregation, the size of the secondary particles is preferably within the above range. The average particle size of the additive is measured by scanning electron microscopy (SEM). Specifically, the average particle size was measured using a surface observation device (VE-9800 manufactured by Keyence Corporation).

[0134] It is preferable that the additive (D) is dispersed in the adhesive layer. If the additive (D) is unevenly distributed, the corrosion inhibitory effect on the metal surface will be localized, making it difficult to obtain a sufficient effect. Here, "additive (D) is dispersed in the adhesive layer" means that when a 5 cm x 5 cm piece is cut from any location after sheet processing and observed under a microscope, there are fewer than three agglomerates of additive (D) exceeding 1000 μm.

[0135] The additive (D) may be embedded in the adhesive layer, or may be partially exposed from the adhesive layer.

[0136] The content of the additive (D) in the adhesive layer in the present invention is preferably 0.01% by mass or more and 30% by mass or less, preferably 0.01% by mass or more and 25% by mass or less, preferably 0.01% by mass or more and 10% by mass or less, and preferably 0.015% by mass or more and 5% by mass or less, based on the total amount of the adhesive layer, in other words, the total amount of the adhesive composition forming the adhesive layer. By setting the content of additive (D) in the adhesive layer within the above range, additive (D) can be sufficiently dispersed in the adhesive layer, and corrosion of the metal surface included in the adherend can be sufficiently suppressed. Note that if the content of additive (D) exceeds the above range, the proportion of the additive in the adhesive is high, which may result in insufficient adhesiveness, such as impaired adhesion to the adherend. On the other hand, if the content is lower than the above range, halogen ions and / or acids containing them cannot be sufficiently captured and neutralized, and the corrosion suppression effect on the metal surface may be difficult to achieve.

[0137] <Other ingredients (E)> The adhesive layer may contain other components (E) as needed in addition to the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C) and additive (D).

[0138] The adhesive layer in the present invention may contain a pressure-sensitive adhesive resin, because this allows the adhesive sheet of the present invention to exhibit good room-temperature lamination properties and further improves the ability to conform to and adhere to unevenness in the adherend surface.

[0139] The adhesive resin preferably has a weight average molecular weight in the range of 2,000 to 2,000,000, more preferably in the range of 5,000 to 1,000,000, and even more preferably in the range of 5,000 to 800,000.

[0140] Examples of the adhesive resin include polyester resin, polyurethane resin, poly(meth)acrylate resin, polyvinyl acetal resin, etc. These adhesive resins may be homopolymers or copolymers. Furthermore, these adhesive resins may be used alone or in combination of two or more.

[0141] The adhesive resin preferably has a glass transition temperature in the range of −30° C. to 20° C., more preferably −25° C. to 10° C. When the adhesive layer contains an adhesive resin having a glass transition temperature within the above range, the adhesive sheet of the present invention can exhibit good adhesiveness and a high elastic modulus at room temperature, and can exhibit good adhesion to the adherend and high bonding strength.

[0142] The glass transition temperature can be calculated as the temperature at which the loss tangent (tanδ), which can be calculated by dividing the loss modulus (G”) by the storage modulus (G′) (G″ / G′), becomes maximum, by using, for example, a dynamic viscoelasticity tester (manufactured by Rheometrics, product name: Ares 2KSTD) to sandwich a test piece of the adhesive resin between parallel disks, which are the measurement section of the tester, and measuring the storage modulus (G′) and loss modulus (G″) at a frequency of 1 Hz.

[0143] The adhesive resin may have a functional group introduced therein that can react with a crosslinking agent or with a functional group contained in the photocurable resin (A) or the thermoplastic resin (B). This allows the adhesive resin to be crosslinked. Examples of the functional group include a hydroxyl group, a carboxyl group, an epoxy group, and an amino group. The functional group is preferably selected appropriately within a range that does not inhibit the polymerization reaction of the photocurable resin (A) and the thermoplastic resin (B).

[0144] The adhesive resin is preferably contained in the adhesive layer, in other words, in an amount of 0.1 to 100 parts by mass, more preferably 1 to 50 parts by mass, and even more preferably 5 to 30 parts by mass, relative to the total amount of the adhesive composition forming the adhesive layer. By adjusting the blending ratio of the adhesive resin within the above range, it is possible to obtain an adhesive sheet that exhibits excellent adhesion at room temperature without reducing the bonding strength of the adhesive layer after curing.

[0145] The adhesive layer of the present invention may contain fillers other than the additive (D), silane coupling agents, phosphoric acid additives, acrylate additives, etc. When the material of the adherend surface contains glass, the adhesive layer may contain a silane coupling agent that is highly reactive with glass, thereby further enhancing adhesion to the adherend. The adhesive layer may also contain a photocurable silane coupling agent that can react with the photocurable resin (A) or the thermoplastic resin (B), etc.

[0146] The adhesive layer of the present invention may further contain optional components such as a softener, a stabilizer, an adhesion promoter, a leveling agent, an antifoaming agent, a plasticizer, a tackifying resin, fibers, an antioxidant, a hydrolysis inhibitor, a thickener, a colorant such as a pigment, a filler, and a tackifying resin.

[0147] <Other> The adhesive layer of the present invention preferably contains one or more resins (AA) having epoxy or oxetanyl groups and a weight-average molecular weight of 100 to 5000, one or more resins (BB) selected from the group consisting of polyester resins, polyurethane resins, acrylic resins, polyvinyl acetal resins, and epoxy resins (thermoplastic epoxy resins) having polymerizable functional groups other than polymerizable unsaturated double bonds and a weight-average molecular weight of 5500 to 2000000, a photopolymerization initiator (C), and one or more additives (D) capable of capturing or neutralizing halogen ions and / or acids containing the halogen ions. Here, resins (AA) and (BB) correspond to the photocurable resin (A) and thermoplastic resin (B), respectively.

[0148] <Physical properties of adhesive layer> The adhesive layer in the present invention preferably has a thickness of 10 μm or more and 3000 μm or less, preferably 20 μm or more and 2500 μm or less, preferably 30 μm or more and 2000 μm or less, and preferably 50 μm or more and 650 μm or less. By setting the thickness of the adhesive layer within the above range, it is possible to achieve excellent handleability before curing, high conformal adhesion to the adherend surface, and metal corrosion inhibition effect. If the thickness of the adhesive layer is smaller than the above range, it may be impossible to incorporate the desired amount of additive (D), resulting in insufficient corrosion inhibition effect on the metal surface or insufficient adhesive strength due to the thin thickness. On the other hand, if the thickness of the adhesive layer is larger than the above range, it may be difficult to process into a sheet shape. As described below, when the adhesive layer in the present invention is a multilayer body, the thickness of the adhesive layer refers to the total thickness of the multilayer body.

[0149] The adhesive layer in the present invention preferably has a loss tangent (tanδ) at 23°C measured at a frequency of 1 Hz of less than 1.5, more preferably 0.01 to 1.0, and even more preferably 0.1 to 0.8, because this allows the adhesive sheet to maintain a constant thickness, provides excellent handling before curing, and improves conformability and adhesion to the adherend surface before and after curing.

[0150] The loss tangent (tanδ) of the adhesive layer was measured by preparing a test specimen by cutting the adhesive layer into a circle with a thickness of 1 mm and a diameter of 8 mm, and using a dynamic viscoelasticity tester (manufactured by Rheometrics, product name: Ares 2KSTD), sandwiching the prepared test specimen between the parallel disks that are the measuring section of the tester, and measuring the storage modulus (G') and loss modulus (G") at a temperature of 23°C and a frequency of 1 Hz. The loss tangent (tanδ) was calculated by dividing the loss modulus (G") by the storage modulus (G'), that is, (G" / G').

[0151] The loss tangent (tan δ) of the adhesive layer can be adjusted by appropriately selecting the composition and average molecular weight of the photocurable resin (A), the thermoplastic resin (B), and other components as necessary.

[0152] The adhesive layer in the present invention preferably has a melting point of 25°C or higher, preferably 30°C or higher, preferably 35°C or higher, and preferably 40°C or higher. The melting point is preferably 120°C or lower, preferably 90°C or lower, and preferably 60°C or lower. More specifically, the melting point of the adhesive layer is preferably within the range of 30°C to 120°C, preferably 30°C to 90°C, and preferably 40°C to 85°C. By setting the melting point of the adhesive layer within the above range, the adhesive sheet of the present invention has excellent handleability before curing and improved conformability and adhesion to the adherend surface. The melting point of the adhesive layer is synonymous with the melting point of the adhesive composition constituting the adhesive layer.

[0153] The melting point of the adhesive layer is the temperature at which the maximum exothermic peak (exothermic peak top) is observed when the temperature is increased from 20°C to 150°C at a rate of 10°C / min using differential scanning calorimetry (DSC), held for 1 minute, cooled to -10°C at a rate of 10°C / min, held for 10 minutes, and then measured again at a rate of 10°C / min.

[0154] The adhesive layer in the present invention has a storage modulus (E') of 25°C at a frequency of 1 Hz after curing. 25 ) is 1.0 × 105 Pa or more, and 1.0 × 10 6 Pa or more is more preferable, and 1.0 × 10 7 It is more preferable that the storage modulus is at least Pa. This is because the adhesive layer after curing exhibits a desired storage modulus under predetermined conditions, which makes it possible to suppress misalignment and deformation of the adhesive layer over time after bonding.

[0155] In addition, the adhesive layer of the present invention has a storage modulus (E'40) of 1.0 x 10 at 40°C at a frequency of 1 Hz. 4 The storage modulus (E'60) at 60°C at a frequency of 1 Hz is preferably 1.0 x 10 4 It is preferable that the storage modulus is equal to or greater than 1 Pa. This is because the adhesive layer after curing exhibits a desired storage modulus under predetermined conditions, making it possible to firmly bond members together.

[0156] The storage modulus of the cured adhesive layer at each temperature was measured using a dynamic viscoelasticity measuring device (manufactured by Rheometrics, product name: RSA-II) using a test piece formed by punching a 100 μm thick cured adhesive layer into the shape of a JIS K 7127 type 5 test piece using a dumbbell cutter.

[0157] In the adhesive sheet of the present invention, the gel fraction of the adhesive layer after curing is preferably 40% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 70% by mass or more and 100% by mass or less, because by keeping the gel fraction within the above range, it becomes possible to firmly bond members together.

[0158] The gel fraction is a value calculated based on the following formula from the mass of the adhesive layer remaining in the solvent after drying and the mass of the adhesive layer before immersion in toluene, after the cured adhesive sheet has been immersed in toluene adjusted to 23°C for 24 hours.

[0159] Gel fraction (mass%) = {(mass of adhesive layer of adhesive sheet remaining undissolved in toluene) / (mass of adhesive layer of adhesive sheet before immersion in toluene)} × 100

[0160] (2) Form of adhesive sheet The adhesive sheet of the present invention may have any configuration as long as it has an adhesive layer containing the above-mentioned composition, and may have any desired structure as required.

[0161] One embodiment (embodiment (I)) of the adhesive sheet of the present invention is an embodiment consisting only of an adhesive layer, i.e., a substrate-less embodiment. The adhesive sheet of embodiment (I) can be an embodiment having only a single adhesive layer composed of an adhesive composition containing at least the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D). Alternatively, the adhesive sheet of embodiment (I) may have only an adhesive layer of a multilayer body consisting of two or more laminated layers, and at least the outermost layers on both sides of the adhesive layer of the multilayer body may be composed of an adhesive composition containing the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D). In particular, it is preferable that the multiple layers constituting the adhesive layer of the multilayer body are all composed of the same or different adhesive compositions containing the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D).

[0162] The adhesive sheet of embodiment (I) may have a release liner disposed on one or both of a pair of opposing main surfaces of the adhesive layer. The adhesive sheet of embodiment (I) is used by peeling off and removing the release liner when bonding to a member. Therefore, in a laminate in which a pair of members are bonded via the adhesive sheet of embodiment (I), the adhesive sheet does not include a release liner.

[0163] Another embodiment of the adhesive sheet of the present invention (Aspect (II)) includes a substrate, a first adhesive layer formed on a first main surface of the substrate, and a second adhesive layer formed on a second main surface of the substrate opposite the first main surface, wherein the first adhesive layer and the second adhesive layer are each composed of the same or different adhesive compositions containing at least the photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D). The adhesive sheet of Aspect (II) can have increased strength as a sheet by having a substrate between the two adhesive layers. In Aspect (II), only one of the first adhesive layer and the second adhesive layer may be composed of an adhesive composition containing at least the photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D).

[0164] In the adhesive sheet of embodiment (II), the substrate is not particularly limited, and examples thereof include plastic films made of polyester resins or polyolefin resins, and plastic foams made of polyolefin resins, polyurethane resins, polychloroprene resins, acrylic resins, etc. The substrate is preferably optically transparent. By irradiating one adhesive layer with light, the other adhesive layer can be activated through the substrate, causing a polymerization reaction.

[0165] The adhesive sheet of embodiment (II) may have a release liner on at least one of the surface of the first adhesive layer opposite the surface that contacts the substrate and the surface of the second adhesive layer opposite the surface that contacts the substrate, or may have a release liner on both surfaces. The adhesive sheet of embodiment (II) is used by peeling off and removing the release liner when bonding to a member. Therefore, in a laminate in which a pair of members are bonded via the adhesive sheet of embodiment (II), the adhesive sheet does not include a release liner.

[0166] Examples of the release liner for the adhesive sheet of each embodiment include paper such as kraft paper, glassine paper, and fine paper; resin films such as polyethylene, polypropylene (OPP, CPP), and polyethylene terephthalate; laminated paper in which the above-mentioned paper and a resin film are laminated together; and the above-mentioned paper that has been sealed with clay, polyvinyl alcohol, or the like and then subjected to a release treatment with a silicone-based resin or the like on one or both sides.

[0167] The adhesive sheet of the present invention preferably has a thickness of 10 μm to 3000 μm, more preferably 20 μm to 2500 μm, even more preferably 30 μm to 2000 μm, and even more preferably 50 μm to 650 μm.

[0168] In the adhesive sheet of the present invention, polymerization is initiated in the adhesive layer upon irradiation with light, and curing proceeds. Because the adhesive layer of the present invention is activated by light, curing does not proceed regardless of the storage temperature before light irradiation, and storage stability before curing is good. Furthermore, in the adhesive layer of the present invention, reactive sites are activated by light irradiation, and the activity is maintained, allowing the curing reaction to proceed even at low temperatures.

[0169] The adhesive sheet of the present invention can accelerate its curing reaction by applying external stimuli such as heat and moisture (humidity) in addition to light. In particular, it is preferable to use a combination of light and heat as a means for curing the adhesive sheet of the present invention. The adhesive sheet is first irradiated with light to activate the adhesive layer and initiate polymerization, and the curing reaction can be accelerated by heating the adhesive sheet after laminating it to a member (adherend). This eliminates the need for curing by high-temperature heating, and the curing reaction can proceed even at low temperatures. When heat is used in combination, the reaction has already begun by light irradiation, so heat is used solely to accelerate the curing reaction. Therefore, high-temperature heating is not necessary, and a good curing reaction can be obtained even at low temperatures and in a short time.

[0170] (3) Manufacturing method of adhesive sheet The adhesive sheet of the present invention can be produced using an adhesive solution prepared by mixing an adhesive composition containing at least the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D) in a solvent. Specifically, the adhesive sheet of the present invention can be produced, for example, by applying the above-described adhesive solution to the surface of a release sheet, drying the solution to form an adhesive layer, and then removing the release sheet. Forming an adhesive layer using an adhesive solution prepared by mixing the adhesive composition in a solvent improves the dispersibility of the additive (D) in the adhesive layer compared to when the adhesive is directly applied.

[0171] The adhesive sheet of the present invention can be produced, for example, by applying the above-mentioned adhesive solution to both sides of a substrate and drying to form an adhesive layer.

[0172] The adhesive sheet of the present invention can be produced, for example, by applying the above-described adhesive solution to the surface of a release sheet, drying it to form an adhesive layer, and then attaching a substrate to the surface of the adhesive layer.

[0173] When producing an adhesive sheet in which two or more adhesive layers made of the same or different compositions are laminated, the sheet can be produced, for example, by applying an adhesive solution containing adhesive composition 1 to both sides of a substrate and drying to form a first adhesive layer 1, and then applying an adhesive solution containing adhesive composition 2 to the surface of first adhesive layer 1 and drying to form a second adhesive layer 2. In this case, at least adhesive composition 2 contains the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D). In particular, it is preferred that both adhesive compositions 1 and 2 contain the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D).

[0174] The adhesive sheet of the present invention can be produced, for example, by applying an adhesive solution containing adhesive composition 1 to the surface of a release sheet and drying to form adhesive layer 1, and then applying an adhesive solution containing another adhesive composition 2 to the surface of adhesive layer 1 and drying to form adhesive layer 2. In this case, at least one of adhesive compositions 1 and 2 contains at least the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D). It is particularly preferred that both adhesive compositions 1 and 2 contain at least the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D).

[0175] The adhesive solution used in the adhesive sheet manufacturing method of the present invention can be prepared by mixing an adhesive composition containing at least the above-mentioned photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and additive (D) with a solvent. Examples of solvents used in the adhesive solution include ester-based solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone-based solvents such as acetone, methyl ketyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; and aromatic hydrocarbon solvents such as toluene and xylene. A dissolver, butterfly mixer, BDM two-axis mixer, planetary mixer, or the like can be used to mix the adhesive composition and solvent.

[0176] The method for producing an adhesive sheet of the present invention includes a drying step for removing the solvent after applying the adhesive solution. The drying step is preferably carried out at a temperature of about 40°C to 120°C, more preferably about 50°C to 90°C. This is because it can suppress the progress of the curing reaction of the adhesive sheet before light irradiation and also suppress foaming on the sheet surface due to rapid evaporation of the solvent, etc.

[0177] (4)Applications The adhesive sheet of the present invention can be used to bond components without being limited by the light transmittance or heat resistance of the components, but is particularly suitable for bonding components with low light transmittance, non-light transmittance, or low heat resistance. As described above, the adhesive sheet of the present invention has a slow curing reaction rate after light irradiation and can retain flexibility even after light irradiation. Therefore, by irradiating the adhesive sheet with light before bonding the components, the curing reaction proceeds without irradiating the adhesive sheet with light through the components or heating and pressurizing at high temperatures, and the components can be firmly bonded.

[0178] The adhesive sheet of the present invention can be suitably used in the manufacture of an image display device. That is, the adhesive sheet of the present invention can be suitably used as a bonding material for joining various members used in an image display device.

[0179] Examples of the image display device include components of flat-panel image display devices using image display panels equipped with LCD, PDP or EL, organic EL, micro LED, quantum dots (QD), etc., such as mobile terminals (PDAs) such as personal computers, mobile phones, smartphones, and tablet PCs, game consoles, televisions (TVs), car navigation systems, touch panels, and pen tablets. Examples of the components include image display panels, circuit boards, rear covers, bezels, frames, and chassis.

[0180] The adhesive sheet of the present invention can also be suitably used to bond components that constitute large image display devices used in industrial applications or advertising.

[0181] 2.Laminate The laminate of the present invention comprises the adhesive sheet described above in the section "1. Adhesive Sheet," a first member bonded to a first main surface of the adhesive sheet, and a second member bonded to a second main surface of the adhesive sheet.

[0182] In the laminate of the present invention, the adhesive layer of the adhesive sheet is cured. That is, in the laminate of the present invention, the first member and the second member are bonded together by the adhesive layer of the adhesive sheet after curing. In other words, the first member and the second member are bonded together by a cured layer of the adhesive composition described in the above section "1. Adhesive Sheet."

[0183] According to the laminate of the present invention, the first and second components are bonded via the adhesive sheet described above in "1. Adhesive Sheet," so the components are less likely to peel and exhibit a high interlayer peel strength. Furthermore, because the adhesive layer of the adhesive sheet contains the desired components, the adherend surface of the metal component or the adherend surface on which the metal part is placed is less likely to corrode due to contact with the adhesive sheet, so the performance of the metal component or the metal part placed on the adherend surface can be maintained.

[0184] In the laminate of the present invention, as long as a first member is bonded to a first main surface of the adhesive sheet described above in the section "1. Adhesive Sheet" and a second member is bonded to a second main surface of the adhesive sheet opposite the first main surface, the numbers of first and second members are not limited. That is, the laminate of the present invention may have one first member bonded to the first main surface of the adhesive sheet and one second member bonded to the second main surface of the adhesive sheet, one first member bonded to the first main surface of the adhesive sheet and multiple second members bonded to the second main surface of the adhesive sheet, or multiple first members bonded to the first main surface of the adhesive sheet and multiple second members bonded to the second main surface of the adhesive sheet.

[0185] The member in the laminate of the present invention may or may not have optical transparency. The preferred optical transmittance of the member is as explained in the above section "1. Adhesive Sheet." The member may or may not have heat resistance, but preferably has heat resistance sufficient to withstand the heating temperature of the heat treatment performed to promote the curing reaction after light irradiation.

[0186] An example of the laminate of the present invention is one in which a first member, the adhesive sheet described above in "1. Adhesive Sheet," and a second member are laminated in this order, and at least one of the first member and the second member includes a metal surface on the surface to be adhered. Both the first member and the second member may include a metal surface on the surface to be adhered. Note that "including a metal surface on the surface to be adhered" is defined in the same way as in "1. Adhesive Sheet."

[0187] In the laminate of the present invention, the types of the first and second members are not particularly limited, but a member having a metal surface on the adherend surface can be preferably used for at least one of the first and second members, since this suppresses metal corrosion caused by lamination with an adhesive sheet. Both the first and second members may be members having a metal surface on the adherend surface.

[0188] The member having a metal surface on the adherend surface is not particularly limited, but is preferably a substrate or a wiring board having metal wiring on one side of the substrate. In particular, in the case of a wiring board having a patterned metal wiring, the surface has unevenness due to the wiring pattern and other components, and the adhesive sheet of the present invention can conform to and adhere to such surface unevenness, thereby enabling a strong bond between the wiring board and other components. Furthermore, since the adhesive layer in the adhesive sheet contains additive (D), even if the adhesive sheet conforms to and adheres to the wiring pattern for a long period of time, corrosion of the metal wiring due to contact over time is unlikely to occur, and deterioration of the functionality of the wiring board can be suppressed for a long period of time.

[0189] When the component is a wiring substrate having a substrate and metal wiring on one side of the substrate, the substrate may or may not be optically transparent. The substrate may be transparent or opaque. Known materials can be used for the substrate, such as glass and insulating resin.

[0190] When the component is a substrate and a wiring board having metal wiring on one side of the substrate, known materials can be used for the metal wiring, such as metal materials such as silver, copper, nickel, tin, bismuth, zinc, indium, palladium, aluminum, chromium, or alloys thereof, and conductive resin materials containing metal particles composed of binder resin and the above-mentioned metal materials. Examples of conductive resin materials include metal pastes or metal nanoinks containing metal particles and binder resin, and metal-carbon inks containing metal particles, carbon materials, and binder resin.

[0191] The laminate of the present invention is preferably a substrate component or semiconductor chip of an image display. The laminate of the present invention is also preferably used in an image display. Examples of the image display device include components of flat-panel image display devices using image display panels equipped with LCD, PDP, EL, organic EL, micro LED, quantum dots (QD), etc., such as mobile terminals (PDAs) such as personal computers, mobile phones, smartphones, and tablet PCs, game consoles, televisions (TVs), car navigation systems, touch panels, and pen tablets. Examples of the components include image display panels, substrate components of image displays, rear covers, bezels, frames, and chassis.

[0192] 3. Manufacturing method of laminate The method for producing a laminate of the present invention is a method for producing a laminate using the adhesive sheet described above in the section "1. Adhesive Sheet," and includes the steps of [1] bonding a first member to the first main surface of the adhesive sheet, [2] bonding a second member to the second main surface of the adhesive sheet, and [3] curing the adhesive layer of the adhesive sheet, and further includes a step of irradiating the first main surface or the second main surface of the adhesive sheet with active energy rays (hereinafter sometimes referred to as step [0]) before step [1] or between steps [1] and [2]. Furthermore, in the method for producing a laminate of the present invention, at least one of the first member and the second member includes a metal surface on the adhesion surface that contacts the adhesive layer.

[0193] If the adhesive sheet of the present invention is the adhesive sheet of the above-mentioned aspect (I), the first and second main surfaces of the adhesive sheet refer to the two opposing outermost surfaces of the adhesive layer of the single layer or multilayer body. If the adhesive sheet of the present invention is the adhesive sheet of the above-mentioned aspect (II), the first and second main surfaces of the adhesive sheet refer to the surface facing the first adhesive layer and the surface facing the second adhesive layer, respectively, of the adhesive sheet of aspect (II).

[0194] In the method for manufacturing a laminate of the present invention, at least one of the first member and the second member may include a metal surface on the adhesion surface that contacts the adhesive layer, and both the first member and the second member may include a metal surface on the adhesion surface that contacts the adhesive layer.

[0195] In the above step [1], it is preferable to press and bond the first member to the first main surface of the adhesive sheet. Also, in the above step [2], it is preferable to press and bond the second member to the second main surface of the adhesive sheet. By pressing and bonding the member to the adhesive sheet, the adhesive sheet can more easily conform to unevenness in the adherend surface of the member, which can increase the adhesion between the adhesive sheet and the member, thereby further increasing the bonding strength between the first member and the second member via the adhesive layer after curing.

[0196] In steps [1] and [2], the pressure when pressing the member to the adhesive sheet can be in the range of 0.1 to 3000 kPa, preferably in the range of 0.5 to 1000 kPa, and more preferably in the range of 1.0 to 500 kPa. Pressing within the above range allows the member to be attached to the adhesive sheet without being damaged, and provides the adhesion required to obtain high bonding strength.

[0197] In steps [1] and [2], the components may be pressure-bonded to the adhesive sheet while heating. Pressure-bonding while heating allows for stronger adhesion and higher bonding strength when bonding the components together via the adhesive sheet. The heating temperature can be set within a range that does not damage the components, cause distortion between the components, deform the components, or cause cracks between the bonding material and the components. It is preferably set to 150°C or less, 120°C or less, 100°C or less, 80°C or less, or 70°C or less. Setting an upper limit for the heating temperature can suppress damage to the components, and can also suppress distortion between the components, causing cracks between the adhesive sheet and the components. The heating temperature can also be set to preferably 5°C or more, 10°C or more, 20°C or more, 30°C or more, or 40°C or more. Setting a lower limit for the heating temperature improves the adhesive sheet's ability to conform to surface irregularities. The pressure-bonding time is not particularly limited as long as it is a time that allows sufficient conformal adhesion and adhesion to the bonded surfaces of the components.

[0198] The step [3] may involve a heat treatment. In the manufacturing method of the present invention, the curing reaction of the adhesive sheet is initiated by irradiation with active energy rays, and the curing proceeds even at room temperature. However, by performing the step [3] with heat, the curing reaction is accelerated when bonding members together via the adhesive sheet, and high bonding strength can be obtained in a shorter time.

[0199] When heat treatment is performed in the above step [3], the heating conditions can be set within a range that does not damage the laminated components, deform the components due to strain between the components, or cause cracks between the adhesive sheet and the components. The heating temperature is preferably 150°C or less, more preferably 120°C or less, and even more preferably 100°C or less, and most preferably 80°C or less to prevent damage to the laminated components and deformation and flow of the bonding material.

[0200] In the above step [3], it is preferable to allow the curing reaction to proceed so that the cured adhesive layer exhibits the gel fraction explained in the above section "1. Adhesive sheet."

[0201] The step of irradiating the first or second main surface of the adhesive sheet with active energy rays (step [0]) can be carried out before step [1]. In this case, steps [1] and [2] are preferably carried out within 24 hours, more preferably within 12 hours, even more preferably within 3 hours, and most preferably within 1 hour after carrying out step [0], because this allows for stronger adhesion and higher bonding strength when the adhesive sheet is attached to a member.

[0202] Furthermore, the step [0] may be carried out between the steps [1] and [2]. In this case, the step [2] is preferably carried out within 24 hours, more preferably within 12 hours, even more preferably within 3 hours, and most preferably within 1 hour after carrying out the step [0], since this allows for stronger adhesion and higher bonding strength when the adhesive sheet is applied to a member.

[0203] As the active energy ray, ultraviolet rays, visible light, etc. are preferably used, and among them, ultraviolet rays are preferably used. In order to efficiently carry out the ultraviolet curing reaction, the ultraviolet rays may be irradiated in an inert gas atmosphere such as nitrogen gas, or in an air atmosphere. Furthermore, if necessary, heat may be used in combination as an energy source, and heating may be performed after light irradiation.

[0204] The light to be irradiated preferably has a wavelength range capable of activating the photopolymerization initiator, and it is particularly preferable to use active energy rays with a wavelength of 300 nm or more and 420 nm or less.

[0205] Examples of light sources for irradiating active energy rays include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, electrodeless lamps (fusion lamps), chemical lamps, black light lamps, xenon lamps, mercury-xenon lamps, short arc lamps, helium-cadmium lasers, argon lasers, sunlight, LEDs, germicidal lamps, carbon arcs, scanning and curtain-type electron beam accelerators, etc. Xenon flash lamps, which can irradiate light in a flashing manner, are preferred because they can minimize the effect of heat.

[0206] The irradiation intensity of the active energy rays is 0.1 to 1000 mW / cm 2 is preferred, 0.5 to 800 mW is more preferred, and 0.1 to 400 mW / cm 2 It is more preferable that the irradiation time of the active energy rays is 1 to 60 seconds, more preferably 5 to 50 seconds, and even more preferably 10 to 40 seconds. By setting the irradiation intensity and time within the above ranges, it is possible to reduce the heat generated when irradiated with active energy rays, and therefore it is possible to suitably adjust the cure rate after irradiating with active energy rays.

[0207] The irradiation of the active energy rays may be carried out in one go or in several divided rounds.

[0208] Specific examples of laminates that can be produced according to the present invention include those described above in the section "2. Laminates."

[0209] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any embodiment that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included within the technical scope of the present disclosure. [Example]

[0210] The present invention will be described in more detail below with reference to examples and comparative examples.

[0211] 1. Synthesis example of thermoplastic resin (B) <Preparation of Polyurethane (B-1)> Into a reaction vessel, 50.3 parts by mass of an aromatic polyester polyol having a number average molecular weight of 1,300 obtained by reacting an ethylene oxide 2-mol adduct of bisphenol A with phthalic acid and adipic acid, 32 parts by mass of an aliphatic polyester polyol having a number average molecular weight of 3,500 obtained by reacting 1,6-hexanediol with dodecanedioic acid, 32.2 parts by mass of polypropylene glycol having a number average molecular weight of 1,000, and 1.8 parts by mass of an ethylene oxide 2-mol adduct of bisphenol A were mixed and heated to 100°C under reduced pressure conditions to dehydrate until the moisture content was 0.05% by mass, thereby obtaining mixture (1).

[0212] Next, this mixture (1) was cooled to 70°C and mixed with 7.9 parts by mass of 4,4'-diphenylmethane diisocyanate, and then the temperature was raised to 100°C and the mixture was reacted for 3 hours until the hydroxyl group content became constant, thereby obtaining polyurethane (B-1). Note that the polyurethane (B-1) has hydroxyl groups as polymerizable functional groups.

[0213] <Preparation of Polyurethane (B-2)> A reaction vessel was mixed with 50.3 parts by mass of an aromatic polyester polyol having a number average molecular weight of 1,300 obtained by reacting an ethylene oxide 2-mol adduct of bisphenol A with phthalic acid and adipic acid, 32 parts by mass of an aliphatic polyester polyol having a number average molecular weight of 3,500 obtained by reacting 1,6-hexanediol and dodecanedioic acid, 32.2 parts by mass of polypropylene glycol having a number average molecular weight of 1,000, and 1.8 parts by mass of an ethylene oxide 2-mol adduct of bisphenol A, and the mixture was heated to 100°C under reduced pressure conditions to dehydrate until the moisture content reached 0.05% by mass, thereby obtaining mixture (2).

[0214] Next, this mixture (2) was cooled to 70°C, and mixed with 4.3 parts by mass of 4,4'-diphenylmethane diisocyanate and 4.3 parts by mass of 2,4'-diphenylmethane diisocyanate, and then the temperature was raised to 100°C and the mixture was reacted for 5 hours until the hydroxyl group content became constant, thereby obtaining polyurethane (B-2). Note that the polyurethane (B-2) has hydroxyl groups as polymerizable functional groups.

[0215] <Preparation of Polyurethane (B-3)> 60 parts by mass of an aliphatic polycarbonate polyol having a number average molecular weight of 2000 obtained by reacting 1,5-pentanediol, 1,6-hexanediol, and a dialkyl carbonate, and 20 parts by mass of a polyester polyol having a number average molecular weight of 1000 obtained by reacting 1,4-butanediol and adipic acid were mixed in a reaction vessel, and the mixture was heated to 100°C under reduced pressure conditions to dehydrate until the moisture content reached 0.05% by mass, thereby obtaining mixture (3).

[0216] Next, mixture (3) was cooled to 70°C and mixed with 20 parts by mass of dicyclohexylmethane-4,4'-diisocyanate, then the temperature was raised to 100°C and the mixture was allowed to react for 3 hours to obtain a urethane prepolymer having an isocyanate group. 100 parts by mass of the urethane prepolymer was heated and melted at 100°C, and this was mixed with 11.4 parts by mass of 2-hydroxyethyl acrylate and 0.01 parts by mass of stannous octoate, and the mixture was allowed to react at 100°C until the NCO% became constant to obtain polyurethane (B-3). Polyurethane (B-3) had a polymerizable unsaturated double bond as the polymerizable functional group, and the isocyanate group content (NCO%) was 0% by mass.

[0217] 2. Creating an adhesive sheet Example 1 33 parts by weight of the polyurethane (B-1), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 45 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 1.6 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), and 40 parts by weight of calcium bicarbonate particles (Shiraishi Calcium Co., Ltd., "BF-200", average particle size 5 μm) were mixed and stirred, and methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight, thereby obtaining an adhesive solution containing adhesive composition (a-1). Note that the calcium bicarbonate particles were a basic solid.

[0218] Next, an adhesive solution containing the adhesive composition (a-1) was applied to the surface of release liner A (a 50 μm-thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-1).

[0219] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0220] Example 2 An adhesive solution containing adhesive composition (a-2) was obtained by mixing and stirring 33 parts by weight of the polyurethane (B-1), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 45 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 1.6 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), 20 parts by weight of calcium bicarbonate particles (Shiraishi Calcium Co., Ltd., "BF-200", average particle size 5 μm), and 16.2 parts by weight of hydrophobic silica particles (Fuji Silysia Co., Ltd., "Sylohorbic 603", average particle size 6.7 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight. The calcium bicarbonate particles were a basic solid, while the hydrophobic silica particles were a non-basic solid with no basic functional groups on their surfaces.

[0221] Next, an adhesive solution containing the adhesive composition (a-2) was applied to the surface of release liner A (a 50 μm thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and then dried to obtain a coating layer of adhesive composition (a-2).

[0222] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0223] Example 3 An adhesive solution containing adhesive composition (a-3) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 2.0 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), and 13.3 parts by weight of calcium bicarbonate particles (Shiraishi Calcium Co., Ltd., "BF-200", average particle size 5 μm), and adding methyl ethyl ketone to adjust the nonvolatile content to 75% by weight. Note that the calcium bicarbonate particles were a basic solid.

[0224] Next, an adhesive solution containing the adhesive composition (a-3) was applied to the surface of release liner A (a 50 μm-thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-3).

[0225] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0226] Example 4 An adhesive solution containing adhesive composition (a-4) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 2.0 parts by weight of a sulfonium salt-based photocationic polymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), 1.7 parts by weight of an ion scavenger (Toagosei Co., Ltd., "IXE-700F", average particle size 1.5 μm), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Chemical Industries, Ltd., "Sylophorbic 603", average particle size 6.7 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight, and the ion scavenger was an inorganic ion scavenger containing both aluminum and magnesium metal atoms. Furthermore, the hydrophobic silica particles did not have basic functional groups on the surface and were non-basic solids.

[0227] Next, an adhesive solution containing the adhesive composition (a-4) was applied to the surface of release liner A (a 50 μm thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-4).

[0228] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0229] Example 5 An adhesive solution containing adhesive composition (a-5) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 2.0 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), 1.7 parts by weight of an ion scavenger (Toagosei Co., Ltd., "IXEPLAS-A3", average particle size 0.5 μm), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Chemical Industries, Ltd., "Sylophorbic 603", average particle size 6.7 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight, and the ion scavenger was an inorganic amphoteric ion scavenger containing three metal atoms: zirconium, aluminum, and magnesium. Furthermore, the hydrophobic silica particles did not have basic functional groups on the surface and were non-basic solids.

[0230] Next, an adhesive solution containing the adhesive composition (a-5) was applied to the surface of release liner A (a 50 μm thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-5).

[0231] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0232] Example 6 An adhesive solution containing adhesive composition (a-6) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 4.0 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), 1.7 parts by weight of an ion scavenger (Toagosei Co., Ltd., "IXEPLAS-A3", average particle size 0.5 μm), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Chemical Industries, Ltd., "Sylophorbic 603", average particle size 6.7 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight, and the ion scavenger was an inorganic amphoteric ion scavenger containing three metal atoms: zirconium, aluminum, and magnesium. Furthermore, the hydrophobic silica particles did not have basic functional groups on the surface and were non-basic solids.

[0233] Next, an adhesive solution containing the adhesive composition (a-6) was applied to the surface of release liner A (a 50 μm thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-6).

[0234] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0235] Example 7 An adhesive solution containing adhesive composition (a-7) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 2.0 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), 0.85 parts by weight of an ion scavenger (Toagosei Co., Ltd., "IXEPLAS-A3", average particle size 0.5 μm), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Co., Ltd., "Sylophorbic 603", average particle size 6.7 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight. The ion scavenger was an inorganic amphoteric ion scavenger containing three metal atoms: zirconium, aluminum, and magnesium. Furthermore, the hydrophobic silica particles did not have basic functional groups on the surface and were non-basic solids.

[0236] Next, an adhesive solution containing the adhesive composition (a-7) was applied to the surface of release liner A (a 50 μm-thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-7).

[0237] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0238] Example 8 An adhesive solution containing adhesive composition (a-8) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 2.0 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), 0.034 parts by weight of an ion scavenger (Toagosei Co., Ltd., "IXEPLAS-A3", average particle size 0.5 μm), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Chemical Ltd., "Sylophorbic 603", average particle size 6.7 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight, and the ion scavenger was an inorganic amphoteric ion scavenger containing three metal atoms: zirconium, aluminum, and magnesium. Furthermore, the hydrophobic silica particles did not have basic functional groups on the surface and were non-basic solids.

[0239] Next, an adhesive solution containing the adhesive composition (a-8) was applied to the surface of release liner A (a 50 μm thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-8).

[0240] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0241] Example 9 An adhesive solution containing adhesive composition (a-9) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 2.0 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), 0.017 parts by weight of an ion scavenger (Toagosei Co., Ltd., "IXEPLAS-A3", average particle size 0.5 μm), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Chemical Ltd., "Sylophorbic 603", average particle size 6.7 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight, and the ion scavenger was an inorganic ion scavenger containing three metal atoms: zirconium, aluminum, and magnesium. Furthermore, the hydrophobic silica particles did not have basic functional groups on the surface and were non-basic solids.

[0242] Next, an adhesive solution containing the adhesive composition (a-9) was applied to the surface of release liner A (a 50 μm-thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-9).

[0243] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0244] Example 10 An adhesive solution containing adhesive composition (a-10) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 2.0 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), 0.0085 parts by weight of an ion scavenger (Toagosei Co., Ltd., "IXEPLAS-A3", average particle size 0.5 μm), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Chemical Ltd., "Sylophorbic 603", average particle size 6.7 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight, and the ion scavenger was an inorganic amphoteric ion scavenger containing three metal atoms: zirconium, aluminum, and magnesium. Furthermore, the hydrophobic silica particles did not have basic functional groups on the surface and were non-basic solids.

[0245] Next, an adhesive solution containing the adhesive composition (a-10) was applied to the surface of release liner A (a 50 μm thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-10).

[0246] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0247] Example 11 An adhesive solution containing adhesive composition (a-11) was obtained by mixing and stirring 33 parts by weight of the polyurethane (B-1), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation, "CEL-2021P"), 45 parts by weight of a cresol novolac epoxy resin (DIC Corporation, "N-685-EXP-S"), 1.6 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), and 84 parts by weight of zinc oxide particles (Sakai Chemical Industry Co., Ltd., "LPZINC-11", average particle size 11 μm). Methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight, and the zinc oxide was an amphoteric metal oxide.

[0248] Next, an adhesive solution containing the adhesive composition (a-11) was applied to the surface of release liner A (a 50 μm-thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (a-11).

[0249] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0250] (Comparative Example 1) An adhesive solution containing adhesive composition (b-1) was obtained by mixing and stirring 33 parts by mass of the polyurethane (B-1), 22 parts by mass of an alicyclic epoxy resin (manufactured by Daicel Corporation, "CEL-2021P"), 45 parts by mass of a cresol novolac epoxy resin (manufactured by DIC Corporation, "N-685-EXP-S"), and 1.6 parts by mass of a sulfonium salt-based cationic photopolymerization initiator (manufactured by San-Apro Co., Ltd., "CPI-100P", solids concentration 50%), and adding methyl ethyl ketone to adjust the nonvolatile content to 75% by mass.

[0251] Next, an adhesive solution containing the adhesive composition (b-1) was applied to the surface of release liner A (a 50 μm thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, thereby obtaining a coating layer of adhesive composition (b-1).

[0252] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0253] (Comparative Example 2) 33 parts by weight of the polyurethane (B-1), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation "CEL-2021P"), 45 parts by weight of a cresol novolac epoxy resin (DIC Corporation "N-685-EXP-S"), 1.6 parts by weight of a sulfonium salt-based cationic photopolymerization initiator (San-Apro Co., Ltd. "CPI-100P", solids concentration 50%), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Corporation "Sylophorbic 603", average particle size 6.7 μm) were mixed and stirred, and methyl ethyl ketone was added to adjust the nonvolatile content to 75% by weight to obtain an adhesive solution containing adhesive composition (b-2). Note that the hydrophobic silica particles were non-basic solids with no basic functional groups on their surfaces.

[0254] Next, an adhesive solution containing the adhesive composition (b-2) was applied to the surface of release liner A (a 50 μm-thick polyethylene terephthalate film with one side treated with a silicone compound for release), using a rod-shaped metal applicator, so that the thickness after drying would be 150 μm. The film was then placed in a dryer at 85°C for 5 minutes to dry, forming a coating layer of adhesive composition (b-2).

[0255] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0256] (Comparative Example 3) 100 parts by mass of the urethane resin (B-3), 43 parts by mass of an alicyclic epoxy resin ("CEL-2021P" manufactured by Daicel Corporation), and 11.4 parts by mass of a sulfonium salt-based cationic photopolymerization initiator ("CPI-100P" manufactured by San-Apro Co., Ltd., solids concentration 50%) were mixed and stirred, and methyl ethyl ketone was added to adjust the nonvolatile content to 75% by mass, thereby obtaining an adhesive solution containing adhesive composition (b-3).

[0257] Next, an adhesive solution containing the adhesive composition (b-3) was applied to the surface of release liner A (a 50 μm-thick polyethylene terephthalate film with one side subjected to release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and the film was placed in a dryer at 85°C for 5 minutes to dry, forming a coating layer of adhesive composition (b-3).

[0258] Furthermore, three of the above coating layers were laminated together to form a 450 μm thick multilayer adhesive layer with release liner A on one side, and release liner B (a 38 μm thick polyethylene terephthalate film with one side release-treated with a silicone compound) was laminated to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0259] (Reference example 1) Liquid adhesive (c-1) was obtained by mixing and stirring 43 parts by weight of the polyurethane (B-2), 22 parts by weight of an alicyclic epoxy resin (Daicel Corporation "CEL-2021P"), 35 parts by weight of a cresol novolac epoxy resin (DIC Corporation "N-685-EXP-S"), 2.0 parts by weight of a sulfonium salt-based photocationic polymerization initiator (San-Apro Co., Ltd. "CPI-100P", solids concentration 50%), 1.7 parts by weight of an ion scavenger (Toa Gosei Co., Ltd. "IXEPLAS-A3", average particle size 0.5 μm), and 20 parts by weight of hydrophobic silica particles (Fuji Silysia Co., Ltd. "Sylophorbic 603", average particle size 6.7 μm) at 110 ° C. The ion scavenger was an inorganic amphoteric ion scavenger containing three metal atoms: zirconium, aluminum, and magnesium, and the hydrophobic silica particles were a non-basic solid.

[0260] 3. Evaluation The adhesive sheets obtained in the Examples and Comparative Examples were evaluated as follows. Note that, for Reference Example 1, the liquid adhesive (c-1) was heated to 100°C, then dropped directly onto release liner B (a 38 μm-thick polyethylene terephthalate film with one side release-treated with a silicone compound), covered with a release liner, and pressed down to a thickness of 450 μm to produce an adhesive sheet, which was then evaluated as follows.

[0261] [Method for evaluating the amount of halogen contained in the cured sheet] The adhesive sheets obtained in the Examples and Comparative Examples (except Comparative Example 3), and the adhesive sheet produced using the adhesive of the Reference Example were each cut into a size of 35 mm wide x 18 mm long to prepare test samples. Next, the test samples were irradiated with an air-cooled mercury lamp (manufactured by Eye Graphics) at an intensity of 300 mW / cm. 2The sample was irradiated with ultraviolet light for 15 seconds. The release liner was not removed during the ultraviolet irradiation. After the ultraviolet irradiation, the test sample was heated at 80°C for 3 hours, then left in a 23°C environment for 30 minutes or more, and cooled to obtain an evaluation sample. The evaluation sample was placed in an XRF sample holder, and the amount of elements was measured under vacuum conditions using a scanning X-ray fluorescence analyzer (ZSX Primus, manufactured by Rigaku). The quantitative results (ppm) of F, Cl, Br, and I were summed to obtain the total halogen amount.

[0262] [Evaluation method for copper foil corrosion] The adhesive sheets obtained in the Examples and Comparative Examples, and the adhesive sheet produced using the adhesive of the Reference Example were each cut to a size of 30 mm wide x 30 mm long to prepare test samples. One of the release liners was removed from each of the test samples, and the sheet was pressed against a 0.35 mm thick electrolytic copper foil with a smooth surface at a pressure of 0.05 MPa for 10 seconds in a temperature environment of 23°C to obtain a patch.

[0263] The above adhesive was applied to an air-cooled mercury lamp (manufactured by Eye Graphics) at an intensity of 300 mW / cm 2 The film was irradiated with ultraviolet light for 15 seconds without removing the release liner.

[0264] After the ultraviolet irradiation, the patch was heated and left at 80°C for 3 hours, and then left in an environment of 23°C for 30 minutes or more before being cooled, to prepare an evaluation sample.

[0265] The evaluation sample was left in an environment of 60°C and 90% RH, and the change in appearance of the bonded surface of the adhesive sheet and electrolytic copper foil (Cu corrosion resistance) was evaluated according to the following criteria. (standard) ◯: No change in appearance was observed after the evaluation sample was left in an environment of 60°C and 90% RH for 100 hours. △: No change in appearance was observed after the evaluation sample was left in an environment of 60°C and 90% RH for 50 hours, but a change in appearance (blackening) was observed after being left for 100 hours. ×: A change in appearance (blackening) of the electrolytic copper foil was observed within 50 hours after the evaluation sample was left in an environment of 60° C. and 90% RH.

[0266] [Method for evaluating the dispersibility of additive (D) in adhesive sheet] The adhesive sheets obtained in the Examples and Comparative Examples, and the adhesive sheet produced using the adhesive of the Reference Example were each cut into a size of 50 mm wide x 50 mm long to serve as test samples. When observed under an optical microscope, the dispersibility of the additive (D) in the sheet was evaluated according to the following criteria. (standard) ◎: Less than one additive-derived agglomerate exceeding 1000 μm and less than one additive-derived agglomerate exceeding 150 μm ○: Less than one additive-derived agglomerate larger than 1000 μm △: 2 to less than 3 additive-derived aggregates over 1000 μm ×: 3 or more additive-derived aggregates larger than 1000 μm

[0267] [Method for evaluating conformability after exposure to active energy rays (method for evaluating conformability to unevenness when force is applied to the adhesive sheet after UV exposure to deflections or unevenness on the adherend surface)] The adhesive sheets obtained in the Examples and Comparative Examples were each cut to 5 cm x 5 cm to prepare test pieces. Next, one release sheet was peeled off from the test piece, and the test piece was pressed and bonded to the center of a 50 μm thick release liner C cut to 7 cm x 7 cm at a pressure of 0.05 MPa for 10 seconds in a temperature environment of 23°C. The above-mentioned bonded product was left in a temperature environment of 23°C for 60 minutes, and then subjected to a 100 mW / cm test using an electrodeless lamp (Fusion Lamp H bulb). 2 The adhesive sheet was irradiated with ultraviolet light for 10 seconds. After the ultraviolet irradiation, the adhesive sheet was left in a temperature environment of 23°C for 10 minutes, and then press-molded for 10 seconds under a pressure of 0.5 MPa using a heat press device heated to 80°C. The ratio of the thickness change of the adhesive sheet after heat pressing to the thickness of the test piece before heat pressing (0.45 mm) (thickness of adhesive sheet after heat pressing / thickness of adhesive sheet before heat pressing) was evaluated according to the following criteria. (standard) ◯: The ratio of the thickness of the adhesive sheet after heat pressing to the thickness of the adhesive sheet before heat pressing was less than 90%. ×: The ratio of the thickness of the adhesive sheet after standing to the thickness of the adhesive sheet before standing was 90% or more and less than 100% (no change).

[0268] [Method for evaluating bondability to materials that do not transmit active energy rays] The adhesive sheets obtained in the Examples and Comparative Examples were each cut to a size of 10 mm wide x 10 mm long, one of the release liners was removed, and the sheets were pressed and bonded to a smooth-surfaced aluminum plate measuring 15 mm wide x 150 mm long x 0.05 mm thick at a temperature of 23°C under a pressure of 0.05 MPa for 10 seconds.

[0269] The above patch was left in a 23°C environment for 60 minutes, and then heated with an electrodeless lamp (Fusion Lamp H bulb) at an intensity of 100 mW / cm 2 The film was irradiated with ultraviolet light for 10 seconds without removing the release liner.

[0270] Next, the above-mentioned UV-irradiated patch was left in a 23°C environment for 10 minutes, after which the release liner was removed and the patch was press-bonded to a smooth-surfaced aluminum plate measuring 15 mm wide x 150 mm long x 0.05 mm thick for 10 minutes using a heat press heated to 70°C under a pressure of 0.5 MPa. The press-bonded laminate was heated to 80°C for 1 hour, then left in a 23°C environment for 30 minutes or more, and cooled to prepare a test sample. The aluminum plate used in this evaluation is a light-opaque material with a light transmittance of 0%.

[0271] The test sample was chucked at both ends of the adherend and subjected to a tensile test in a 180° direction at a pulling rate of 10 mm / min using a tensile tester, thereby determining the shear adhesive strength [MPa] of the test sample.

[0272] The evaluation results are shown in the table below.

[0273] [Table 1]

[0274] [Table 2]

[0275] [Table 3]

[0276] [Table 4]

[0277] [Table 5]

[0278] The adhesive sheets of the Examples exhibited good conformability after exposure to active energy rays, demonstrating that corrosion was suppressed even when laminated to a metal surface (copper foil). On the other hand, the adhesive sheet of Comparative Example 1, in which the adhesive layer did not contain additive (D), and the adhesive sheet of Comparative Example 2, in which the adhesive layer contained a non-basic solid, exhibited good conformability after exposure to active energy rays, but corrosion of the metal surface (electrodeposited copper foil) was confirmed. The adhesive sheets of the Examples and Comparative Examples had similar amounts of halogen ions in the adhesive layer after curing, but the adhesive sheet of the Examples exhibited better corrosion resistance to the electrolytic copper foil than the adhesive sheet of the Comparative Examples. This suggests that the inclusion of additive (D) in the adhesive layer resulted in the capture or neutralization of halogen ions and / or acids containing the halogen ions by additive (D), thereby suppressing acid-induced corrosion of the electrolytic copper foil.

[0279] Among the adhesive sheets of the examples, the adhesive sheets of Examples 1 to 10, which contained calcium bicarbonate or an inorganic ion scavenger, exhibited better metal corrosion resistance with a smaller content of additive (D) than the adhesive sheet of Example 11, which contained zinc oxide. Furthermore, the adhesive sheets of Examples 4 to 10, which contained an inorganic ion scavenger, exhibited better metal corrosion resistance with an even smaller content of additive (D) than the adhesive sheets of Examples 1 to 3, which contained calcium bicarbonate.

[0280] The adhesive sheet of Comparative Example 3, which did not simultaneously contain a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, and a photopolymerization initiator (C), exhibited poor conformability after irradiation with active energy rays and poor adhesion to members that do not transmit active energy rays. This suggests that the adhesive sheet of Comparative Example 3 does not function as a delayed-cure adhesive sheet. Furthermore, the adhesive sheet of Reference Example 1 was evaluated as good in corrosion resistance as the Examples, but the dispersibility of the additive (D) in the adhesive was poor, and processing problems such as coating defects were observed when applying the adhesive.

Claims

1. an epoxy resin (A); a polyurethane resin (B) having a hydroxyl group; a photopolymerization initiator (C); one or more additives (D) having a function of capturing or neutralizing halogen ions and / or acids containing the halogen ions; an adhesive sheet having an adhesive layer comprising: In the adhesive layer The content of the epoxy resin (A) is 25% by mass to 75% by mass, the content of the polyurethane resin (B) having a hydroxyl group is 20% by mass to 50% by mass, The content of the photopolymerization initiator (C) is 0.1% by mass to 10% by mass, An adhesive sheet in which the content of the additive (D) is 0.01% by mass or more and 30% by mass or less.

2. 2. The adhesive sheet according to claim 1, wherein the additive (D) is one or more compounds selected from the group consisting of inorganic ion scavengers and basic solids.

3. The adhesive sheet according to claim 2 , wherein the basic solid is an inorganic salt.

4. 3. The adhesive sheet according to claim 2, wherein the inorganic ion scavenger is a compound selected from the group consisting of inorganic anion scavenger and inorganic amphoteric ion scavenger.

5. The adhesive sheet according to any one of claims 1 to 4, wherein the adhesive layer has a thickness of 10 µm or more and 3000 µm or less.

6. The adhesive sheet according to any one of claims 1 to 5, wherein the additive (D) is dispersed in the adhesive layer.

7. 7. The adhesive sheet according to claim 1, wherein the photopolymerization initiator (C) is a photocationic polymerization initiator.

8. The adhesive sheet according to any one of claims 1 to 7, which is used for bonding an adherend that includes a metal surface on the adhesion surface.

9. The adhesive sheet according to any one of claims 1 to 8, which is used to bond a substrate and a wiring board having metal wiring on one surface of the substrate.

10. A laminate comprising: the adhesive sheet according to any one of claims 1 to 9; a first member bonded to a first main surface of the adhesive sheet; and a second member bonded to a second main surface of the adhesive sheet.

11. The laminate according to claim 10 , wherein at least one of the first member and the second member includes a metal surface on the surface to be adhered to the adhesive sheet.

12. 12. The laminate according to claim 10, wherein at least one of the first member and the second member is a substrate and a wiring board having metal wiring on one surface of the substrate.

13. The laminate according to any one of claims 10 to 12, which is used in an image display device.

14. A method for producing a laminate using the adhesive sheet according to any one of claims 1 to 9, comprising: A step [1] of bonding a first member to a first main surface of the adhesive sheet; a step [2] of bonding a second member to a second main surface of the adhesive sheet; and step [3] of curing the adhesive layer of the adhesive sheet, The method further comprises a step of irradiating the first main surface or the second main surface of the adhesive sheet with active energy rays before the step [1] or between the step [1] and the step [2], A method for manufacturing a laminate, wherein at least one of the first member and the second member includes a metal surface on the surface that comes into contact with the adhesive sheet.

15. 15. The method for manufacturing a laminate according to claim 14, wherein at least one of the first member and the second member is a wiring board having a substrate and metal wiring arranged on one surface of the substrate.

16. The method for producing a laminate according to claim 14 or 15, wherein the laminate is a substrate part of an image display or a semiconductor chip.

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