adhesive composition

Abstract

The present invention provides an adhesive composition comprising the following components (A) to (C): (A) an organic binder, (B) a layered clay mineral, and (C) a compound having a maximum absorption wavelength in the wavelength range of 300 to 430 nm.

Description

[Technical Field]

[0001] The present invention relates to an adhesive composition suitable for forming an adhesive layer in an optical device such as an organic EL display device. [Background technology]

[0002] Organic EL devices are light-emitting devices that use organic substances as light-emitting materials. They have attracted attention in recent years because they can emit high-brightness light at low voltages. Display devices (displays) using organic EL devices have been increasingly used in various applications, such as mobile phones and televisions. However, organic EL devices are known to suffer from issues such as degradation due to short-wavelength light, resulting in discoloration and a shortened lifespan. For example, Patent Document 1 discloses a method for blocking light with wavelengths of 390 nm or less using a display window film having a layer containing a UV absorber to prevent UV-induced degradation of organic EL devices. Patent Document 2 also proposes suppressing the transmission of light with wavelengths of 380 to 430 nm in addition to UV light, and discloses a method for preventing degradation of organic EL devices by providing an organic EL display device with a layer containing a UV absorber and a dye compound whose absorption spectrum has a maximum absorption wavelength in the 380 to 430 nm wavelength range. Device degradation due to short-wavelength light is also a problem for other optical devices, such as solar cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-504622 [Patent Document 2] Japanese Patent Application Publication No. 2018-28974 Summary of the Invention [Problem to be solved by the invention]

[0004] Forming an adhesive layer having the ability to absorb light in the wavelength range of 300 to 430 nm (hereinafter sometimes abbreviated as "light absorption ability in the short wavelength range") on an optical device such as an organic electroluminescence display device using an adhesive containing a compound having a maximum absorption wavelength in the wavelength range of 300 to 430 nm is effective in suppressing light degradation of the optical device. In order to increase the light absorption ability in the short wavelength range, it is thought that the content of the compound in the adhesive can be increased.

[0005] However, there is a limit to the solubility of the compound in the adhesive, and if the content is too high, problems such as (1) crystallization of the compound, (2) leakage of the compound from the adhesive, and (3) discoloration of the adhesive may occur. Therefore, there is a need for a means to improve the short-wavelength light absorption ability of the adhesive layer other than increasing the content of the compound. In addition, the adhesive layer in such optical devices must also be transparent.

[0006] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an adhesive composition that has the ability to absorb light in the wavelength range of 300 to 430 nm and can form an adhesive layer with good transparency. [Means for solving the problem]

[0007] The present invention that can achieve the above object is as follows. [1] The following components (A) to (C): (A) an organic binder; (B) layered clay minerals, and (C) Compounds with a maximum absorption wavelength in the wavelength range of 300 to 430 nm 1. An adhesive composition comprising: [2] The adhesive composition according to [1] above, wherein component (B) comprises at least one selected from hydrotalcite and layered silicate minerals. [3] The adhesive composition according to [1] above, wherein component (B) contains hydrotalcite. [4] The adhesive composition according to [1] above, wherein component (B) contains semi-calcined hydrotalcite. [5] The adhesive composition according to any one of [1] to [4] above, wherein the content of component (A) is 25 to 95 mass % relative to 100 mass % of the nonvolatile content of the adhesive composition. [6] The adhesive composition according to any one of [1] to [5] above, wherein the content of component (B) is 1 to 60 mass % relative to 100 mass % of the nonvolatile content of the adhesive composition. [7] The adhesive composition according to any one of [1] to [6] above, wherein the content of component (C) is 0.05 to 15 mass % relative to 100 mass % of the nonvolatile content of the adhesive composition. [8] The adhesive composition according to any one of [1] to [7] above, wherein component (A) comprises at least one selected from an olefin resin and an epoxy resin. [9] The adhesive composition according to any one of [1] to [8] above, which is used to form an adhesive layer in an optical device.

[10] The adhesive composition according to [9] above, wherein the optical device is an organic electroluminescence display device.

[0008]

[11] An adhesive sheet comprising a support and an adhesive layer formed on the support from the adhesive composition according to any one of [1] to [8] above.

[12] The adhesive sheet according to

[11] above, which is used to form an adhesive layer in an optical device.

[13] The adhesive sheet according to

[12] above, wherein the optical device is an organic electroluminescence display device.

[0009]

[14] An optical device having an adhesive layer formed from the adhesive composition according to any one of [1] to [8] above.

[15] An organic EL display device having an adhesive layer formed from the adhesive composition according to any one of [1] to [8] above. [Effects of the Invention]

[0010] According to the present invention, it is possible to obtain an adhesive composition that has the ability to absorb light in the wavelength range of 300 to 430 nm and that can form an adhesive layer with good transparency. DETAILED DESCRIPTION OF THE INVENTION

[0011] The adhesive composition of the present invention comprises the following components (A) to (C): (A) an organic binder; (B) layered clay minerals, and (C) Compounds with a maximum absorption wavelength in the wavelength range of 300 to 430 nm The present invention is characterized by the combined use of components (B) and (C). By using both components (B) and (C), it is possible to improve the light absorption ability in the short wavelength region (i.e., the ability to absorb light in the wavelength region of 300 to 430 nm) of an adhesive layer formed from the adhesive composition while maintaining transparency, compared to when only one of these components is used. Each component will be described below in order. The examples and preferred descriptions given below can be combined as long as they are not contradictory.

[0012] <(A) Organic binder> The organic binder, component (A), refers to a resin or rubber capable of fixing component (B) (i.e., a layered clay mineral) and component (C) (i.e., a compound having a maximum absorption wavelength in the wavelength range of 300 to 430 nm). Component (A) may be used alone or in combination of two or more types. Furthermore, either a resin or a rubber may be used alone or in combination of two or more types. Furthermore, a resin and a rubber may be used in combination as component (A). Known organic binder resins and / or rubbers can be used as component (A).

[0013] The resin may be either a thermoplastic resin or a thermosetting resin. A tackifying resin may also be used as the resin. The thermoplastic resin, thermosetting resin, and tackifying resin may each be used alone or in combination of two or more. A mixture of these (for example, a mixture of a thermoplastic resin and a tackifying resin) may also be used as the resin. The resin and rubber will be described below in order.

[0014] (thermoplastic resin) Examples of thermoplastic resins include phenoxy resins, acrylic resins, polyvinyl acetal resins, butyral resins, polyimide resins, polyamideimide resins, polyethersulfone resins, polysulfone resins, and olefin-based resins (e.g., ethylene-based resins, propylene-based resins, butene-based resins, and isobutylene-based resins).

[0015] The number-average molecular weight of the thermoplastic resin is not particularly limited, but from the viewpoint of achieving good coatability of the adhesive composition varnish and good compatibility with other components in the composition, it is preferably 1,000,000 or less, more preferably 750,000 or less, even more preferably 500,000 or less, and even more preferably 400,000 or less. On the other hand, from the viewpoint of preventing cissing during application of the adhesive composition varnish, exhibiting moisture resistance of the formed adhesive layer, and improving mechanical strength, it is preferably 500 or more, more preferably 700 or more. The number-average molecular weight is measured by gel permeation chromatography (GPC) (polystyrene equivalent). Specifically, the number average molecular weight according to the GPC method can be measured using a Shimadzu Corporation LC-9A / RID-6A measuring apparatus, a Showa Denko Corporation Shodex K-800P / K-804L / K-804L column, toluene or the like as a mobile phase at a column temperature of 40°C, and calculated using a calibration curve of standard polystyrene.

[0016] When a thermoplastic resin is used as component (A), the thermoplastic resin preferably comprises an olefin-based resin. Here, the term "olefin-based resin" in the present invention refers to a resin containing structural units derived from olefins (hereinafter sometimes abbreviated as "olefin units"), in which the amount of olefin units is 50% by mass or more per 100% by mass of all structural units (i.e., the sum of all structural units). Modified olefin-based resins having functional groups (e.g., epoxy groups, acid anhydride groups, etc.) are also included in the "olefin-based resin" in the present invention when the amount of olefin units is 50% by mass or more of all structural units. Furthermore, modified olefin-based resins that can form crosslinked structures via their functional groups and that have thermoplastic properties by themselves are also included in the "thermoplastic resin" in the present invention.

[0017] The olefin resin may be used alone or in combination of two or more. Preferred olefin resins include ethylene, propylene, butene, and isobutylene resins. These olefin resins may be homopolymers or copolymers such as random copolymers and block copolymers. Examples of copolymers include copolymers of two or more olefins, and copolymers of olefins with non-conjugated dienes, styrene, and other monomers other than olefins. Preferred examples of copolymers include ethylene-non-conjugated diene copolymers, ethylene-propylene copolymers, ethylene-propylene-non-conjugated diene copolymers, ethylene-butene copolymers, propylene-butene copolymers, propylene-butene copolymers, propylene-butene-non-conjugated diene copolymers, styrene-isobutylene copolymers, and styrene-isobutylene-styrene copolymers. Preferred olefin resins include isobutylene-modified resins, styrene-isobutylene-modified resins, and modified propylene-butene resins.

[0018] From the viewpoint of imparting excellent physical properties (e.g., adhesiveness) to the adhesive layer, the olefin-based resin preferably comprises at least one selected from an olefin-based resin having an acid anhydride group (i.e., a carbonyloxycarbonyl group (-CO-O-CO-)) and an olefin-based resin having an epoxy group, and more preferably comprises an olefin-based resin having an acid anhydride group and an olefin-based resin having an epoxy group.

[0019] The olefin resin having an acid anhydride group can be obtained, for example, by graft-modifying an olefin resin with an unsaturated compound having an acid anhydride group under radical reaction conditions. The unsaturated compound having an acid anhydride group may also be radically copolymerized with an olefin or the like. Examples of unsaturated compounds having an acid anhydride group include succinic anhydride, maleic anhydride, and glutaric anhydride. Only one type of unsaturated compound having an acid anhydride group may be used, or two or more types may be used in combination.

[0020] Similarly, an olefin resin having an epoxy group can be obtained by, for example, graft-modifying an olefin resin with an unsaturated compound having an epoxy group under radical reaction conditions. Alternatively, the unsaturated compound having an epoxy group may be radically copolymerized with an olefin or the like. Examples of unsaturated compounds having an epoxy group include glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, and allyl glycidyl ether. Only one type of unsaturated compound having an epoxy group may be used, or two or more types may be used in combination.

[0021] The concentration of acid anhydride groups in the olefin resin having acid anhydride groups is preferably 0.05 to 10 mmol / g, more preferably 0.1 to 5 mmol / g. The concentration of acid anhydride groups is determined from the acid value, which is defined as the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of resin, as described in JIS K 2501. The amount of the olefin resin having acid anhydride groups in the olefin resin is preferably 0 to 70 mass%, more preferably 5 to 50 mass%.

[0022] The epoxy group concentration in the epoxy group-containing olefin resin is preferably 0.05 to 10 mmol / g, more preferably 0.1 to 5 mmol / g. The epoxy group concentration is determined from the epoxy equivalent obtained based on JIS K 7236-1995. The amount of the epoxy group-containing olefin resin in the olefin resin is preferably 0 to 70 mass%, more preferably 5 to 50 mass%.

[0023] From the viewpoint of imparting excellent physical properties such as moisture resistance, the olefin resin preferably contains both an olefin resin having an acid anhydride group and an olefin resin having an epoxy group. In such an olefin resin, the acid anhydride group and the epoxy group react with each other by heating to form a crosslinked structure, thereby forming an adhesive layer with excellent moisture resistance. It is desirable to form the crosslinked structure beforehand when producing the adhesive sheet. The ratio of the olefin resin having an acid anhydride group to the olefin resin having an epoxy group is not particularly limited as long as an appropriate crosslinked structure can be formed, but the molar ratio of the epoxy group to the acid anhydride group (epoxy group:acid anhydride group) is preferably 100:10 to 100:200, more preferably 100:50 to 100:150, and particularly preferably 100:90 to 100:110.

[0024] The number-average molecular weight of the olefin resin is not particularly limited, but from the viewpoint of achieving good coatability of the adhesive composition varnish containing an organic solvent and good compatibility with other components in the adhesive composition, it is preferably 1,000,000 or less, more preferably 750,000 or less, even more preferably 500,000 or less, even more preferably 400,000 or less, even more preferably 300,000 or less, particularly preferably 200,000 or less, and most preferably 150,000 or less. On the other hand, from the viewpoints of preventing cissing during application of the adhesive composition varnish, exhibiting moisture resistance of the formed adhesive layer, and improving mechanical strength, the number-average molecular weight is preferably 500 or more, more preferably 700 or more. The number-average molecular weight in the present invention is measured by gel permeation chromatography (GPC) (polystyrene equivalent). Specifically, the number average molecular weight according to the GPC method can be measured using a Shimadzu Corporation LC-9A / RID-6A measuring apparatus, a Showa Denko Corporation Shodex K-800P / K-804L / K-804L column, toluene or the like as a mobile phase at a column temperature of 40°C, and calculated using a calibration curve of standard polystyrene.

[0025] The olefin resin is preferably amorphous from the viewpoint of suppressing a decrease in fluidity due to thickening of the adhesive composition varnish containing an organic solvent. Here, amorphous means that the olefin resin does not have a clear melting point. For example, an olefin resin can be used that does not show a clear peak when its melting point is measured by DSC (differential scanning calorimetry).

[0026] Next, specific examples of olefin resins will be described. Specific examples of isobutylene resins include BASF's "Opanol B100" (viscosity average molecular weight: 1,110,000) and BASF's "B50SF" (viscosity average molecular weight: 400,000).

[0027] Specific examples of butene-based resins include "HV-1900" (polybutene, number-average molecular weight: 2,900) manufactured by JXTG Nippon Oil & Energy Corporation, and "HV-300M" (maleic anhydride-modified liquid polybutene (modified product of "HV-300" (number-average molecular weight: 1,400)), number-average molecular weight: 2,100, number of carboxy groups constituting the acid anhydride group: 3.2 / molecule, acid value: 43.4 mg KOH / g, acid anhydride group concentration: 0.77 mmol / g) manufactured by Toho Chemical Industry Co., Ltd.

[0028] Specific examples of styrene-isobutylene copolymers include Kaneka Corporation's "SIBSTAR T102" (styrene-isobutylene-styrene block copolymer, number average molecular weight: 100,000, styrene content: 30% by mass), Seiko PMC's "T-YP757B" (maleic anhydride-modified styrene-isobutylene-styrene block copolymer, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 100,000), and Seiko PMC's "T-YP766" (glycidyl methacrylate-modified styrene-isobutylene-styrene block copolymer, epoxy resin). Examples of such copolymers include "T-YP8920" manufactured by Seiko PMC (maleic anhydride-modified styrene-isobutylene-styrene copolymer, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 35,800), and "T-YP8930" manufactured by Seiko PMC (glycidyl methacrylate-modified styrene-isobutylene-styrene copolymer, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 48,700).

[0029] Specific examples of ethylene-based resins or propylene-based resins include "EPT X-3012P" (ethylene-propylene-5-ethylidene-2-norbornene copolymer) manufactured by Mitsui Chemicals, Inc., "EPT1070" (ethylene-propylene-dicyclopentadiene copolymer) manufactured by Mitsui Chemicals, Inc., and "TAFMER A4085" (ethylene-butene copolymer) manufactured by Mitsui Chemicals, Inc.

[0030] Specific examples of ethylene-methyl methacrylate copolymers include "T-YP429" manufactured by Seiko PMC (a 20% by mass toluene solution of maleic anhydride-modified ethylene-methyl methacrylate copolymer (amount of methyl methacrylate units per 100% by mass of ethylene units and methyl methacrylate units: 32% by mass, acid anhydride group concentration: 0.46 mmol / g, number average molecular weight: 2,300)), and "T-YP430" manufactured by Seiko PMC (a 20% by mass toluene solution of maleic anhydride-modified ethylene-methyl methacrylate copolymer (amount of methyl methacrylate units per 100% by mass of ethylene units and methyl methacrylate units: 32% by mass, acid anhydride group concentration: 0.46 mmol / g, number average molecular weight: 2,300)). Examples of such copolymers include "T-YP431" manufactured by Seiko PMC (a 20% by mass toluene solution of glycidyl methacrylate-modified ethylene-methyl methacrylate copolymer (epoxy group concentration: 0.64 mmol / g, number average molecular weight: 2,400)), and "T-YP432" manufactured by Seiko PMC (glycidyl methacrylate-modified ethylene-methyl methacrylate copolymer, epoxy group concentration: 1.63 mmol / g, number average molecular weight: 3,100).

[0031] Specific examples of propylene-butene copolymers include "T-YP341" manufactured by Seiko PMC (a 20% by mass Swazol solution of glycidyl methacrylate-modified propylene-butene random copolymer (amount of butene units per 100% by mass of propylene units and butene units: 29% by mass, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 155,000)), "T-YP279" manufactured by Seiko PMC (maleic anhydride-modified propylene-butene random copolymer, amount of butene units per 100% by mass of propylene units and butene units: 36% by mass, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 35,000), and "T-YP276" manufactured by Seiko PMC (glycidyl methacrylate-modified propylene-butene random copolymer, amount of propylene units and butene units: 36% by mass, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 35,000). Examples of such copolymers include "T-YP312" manufactured by Seiko PMC (a 40% by mass toluene solution of maleic anhydride-modified propylene-butene random copolymer (amount of butene units per 100% by mass of the total of propylene units and butene units: 29% by mass, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 60,900)), and "T-YP313" manufactured by Seiko PMC (a 20% by mass toluene solution of glycidyl methacrylate-modified propylene-butene random copolymer (amount of butene units per 100% by mass of the total of propylene units and butene units: 29% by mass, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 155,000)).

[0032] When the olefin resin contains an olefin resin having an epoxy group, an olefin resin having a functional group other than an acid anhydride group that can react with the epoxy group may be used. Examples of the functional group include a hydroxyl group, a phenolic hydroxyl group, an amino group, and a carboxyl group.

[0033] When the olefin resin contains an olefin resin having an acid anhydride group, an olefin resin having a functional group other than an epoxy group that can react with the acid anhydride group may be used. Examples of the functional group include a hydroxyl group, a primary or secondary amino group, a thiol group, and an oxetane group.

[0034] There are no particular limitations on the content of the thermoplastic resin (particularly, olefin-based resin). From the viewpoint of good coatability of the adhesive composition varnish, when a thermoplastic resin (particularly, an olefin-based resin) is used, the content is preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, relative to 100% by mass of the nonvolatile content of the adhesive composition. Furthermore, the content of the olefin-based resin is preferably 25% by mass or more, more preferably 30% by mass or more, and even more preferably 35% by mass or more, relative to 100% by mass of the nonvolatile content of the adhesive composition.

[0035] (thermosetting resin) Examples of thermosetting resins include epoxy resins, phenolic resins, naphthol resins, benzoxazine resins, active ester resins, cyanate ester resins, carbodiimide resins, amine resins, and acid anhydride resins.

[0036] When a thermosetting resin is used as the organic binder, the thermosetting resin preferably contains an epoxy resin. The epoxy resin may have two or more epoxy groups per molecule on average. However, as described above, even if the resin contains epoxy groups, if the amount of olefin units in the resin is 50% by mass or more of the total structural units, the resin is included in the "olefin-based resin" of the present invention. Examples of epoxy resins include hydrogenated epoxy resins (hydrogenated bisphenol A epoxy resins, hydrogenated bisphenol F epoxy resins, etc.), fluorine-containing epoxy resins, linear aliphatic epoxy resins, cyclic aliphatic epoxy resins, bisphenol A epoxy resins, biphenyl epoxy resins, biphenyl aralkyl epoxy resins, fluorene epoxy resins, naphthol epoxy resins, naphthalene epoxy resins, bisphenol F epoxy resins, phosphorus-containing epoxy resins, bisphenol S epoxy resins, aromatic glycidylamine epoxy resins (e.g., tetraglycidyldiaminodiphenyl ether). phenylmethane, triglycidyl-p-aminophenol, diglycidyl toluidine, diglycidyl aniline, etc.), alicyclic epoxy resins, phenol novolac epoxy resins, alkylphenol epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, epoxy resins having a butadiene structure, diglycidyl ethers of bisphenols, diglycidyl ethers of naphthalenediol, diglycidyl ethers of phenols, diglycidyl ethers of alcohols, and alkyl-substituted versions of these epoxy resins.

[0037] The epoxy resin may be used alone or in combination of two or more. From the viewpoint of reactivity and the like, the epoxy equivalent of the epoxy resin is preferably 50 to 5,000, more preferably 50 to 3,000, even more preferably 80 to 2,000, and particularly preferably 100 to 1,500. The "epoxy equivalent" refers to the number of grams (g / eq) of resin containing 1 gram equivalent of epoxy groups, and is measured according to the method specified in JIS K 7236. The weight average molecular weight of the epoxy resin is preferably 5,000 or less.

[0038] The epoxy resin may be either liquid or solid, and a liquid epoxy resin may be used in combination with a solid epoxy resin. Here, "liquid" and "solid" refer to the state of the epoxy resin at room temperature (25°C) and atmospheric pressure (1 atm). From the viewpoints of coatability, processability, and adhesiveness, it is preferable that 10 mass% or more of the total epoxy resin used be liquid epoxy resin. From the viewpoints of kneadability with hydrotalcite and varnish viscosity, it is particularly preferable to use a liquid epoxy resin in combination with a solid epoxy resin. The mass ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin:solid epoxy resin) is preferably 1:2 to 1:0, more preferably 1:1.5 to 1:0.

[0039] When a thermosetting resin is used as component (A), the content thereof is preferably 25 to 95 mass%, more preferably 30 to 95 mass%, and even more preferably 35 to 95 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition.

[0040] When an epoxy resin is used as component (A), the content thereof is preferably 25 to 95 mass%, more preferably 30 to 95 mass%, and even more preferably 35 to 95 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition.

[0041] When an epoxy resin is used as component (A), a phenoxy resin, which is a thermoplastic resin, may also be used as component (A). When an epoxy resin and a phenoxy resin are used in combination, the content of the epoxy resin is preferably 25 to 90 mass%, more preferably 30 to 90 mass%, and even more preferably 40 to 90 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition, and the content of the phenoxy resin is preferably 0.1 to 60 mass%, more preferably 3 to 60 mass%, and even more preferably 5 to 50 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition.

[0042] When an epoxy resin and a phenoxy resin are used in combination, the weight-average molecular weight of the epoxy resin is preferably 5,000 or less, and the weight-average molecular weight of the phenoxy resin is preferably 10,000 to 500,000, more preferably 20,000 to 300,000. These weight-average molecular weights are measured by gel permeation chromatography (GPC) (polystyrene equivalent).

[0043] (tackifying resin) When a thermoplastic resin (particularly an olefin-based resin) and / or rubber is used as component (A), it is preferable to use a tackifier resin to improve the adhesiveness of the adhesive composition. The tackifier resin may be used alone or in combination of two or more types.

[0044] Examples of tackifying resins include terpene resins, terpene phenol resins, rosin tackifying resins, hydrogenated terpene resins, aromatic-modified terpene resins, coumarone resins, indene resins, petroleum resins (aliphatic petroleum resins, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, alicyclic petroleum resins, dicyclopentadiene petroleum resins, hydrogenated dicyclopentadiene petroleum resins, etc.), saturated aliphatic hydrocarbon resins, and cyclohexane ring-containing saturated hydrocarbon resins.

[0045] Commercially available tackifying resins include, for example: Terpene resins include, for example, YS Resin PX and YS Resin PXN (both manufactured by Yasuhara Chemical Co., Ltd.); Aromatic modified terpene resins include, for example, YS Resin TO and TR series (both manufactured by Yasuhara Chemical Co., Ltd.); Hydrogenated terpene resins include, for example, Clearon P, Clearon M, and Clearon K series (all manufactured by Yasuhara Chemical Co., Ltd.); Terpene phenol resins include, for example, YS Polystar 2000, Polystar U, Polystar T, Polystar S, and Mighty Ace G (all manufactured by Yasuhara Chemical Co., Ltd.); Saturated aliphatic hydrocarbon resins include, for example, Escorez 5300 series and 5600 series (both manufactured by ExxonMobil Corporation), Alcon P100, Alcon P125, and Alcon P140 (all manufactured by Arakawa Chemical Co., Ltd.); Examples of cyclohexane ring-containing saturated hydrocarbon resins include TFS13-030 (manufactured by Arakawa Chemical Industries, Ltd.). Examples of aromatic petroleum resins include ENDEX155 (manufactured by Eastman Co., Ltd.). Examples of aliphatic aromatic copolymer petroleum resins include Quintone D100 (manufactured by Zeon Corporation). Examples of alicyclic petroleum resins include Quintone 1325 and Quintone 1345 (both manufactured by Zeon Corporation).

[0046] When the adhesive composition is used in sheet form, the softening point of the tackifier resin is preferably 50 to 200° C., more preferably 50 to 180° C., and even more preferably 50 to 150° C., from the viewpoint that the sheet softens during the lamination step of the adhesive sheet and has the desired heat resistance. The softening point is measured by the ring and ball method in accordance with JIS K2207.

[0047] The content of the tackifier resin in the adhesive composition is not particularly limited. However, from the viewpoint of maintaining good moisture resistance of the adhesive composition, when a tackifier resin is used, the content is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less, relative to 100% by mass of the nonvolatile content of the adhesive composition. On the other hand, from the viewpoint of sufficient adhesiveness, when a tackifier resin is used, the content is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, relative to 100% by mass of the nonvolatile content of the adhesive composition.

[0048] From the viewpoint of the adhesiveness, moisture resistance, compatibility, etc. of the composition, the tackifying resin is preferably a saturated aliphatic hydrocarbon resin, an aromatic petroleum resin, an aliphatic-aromatic copolymer petroleum resin, or an alicyclic petroleum resin, and more preferably a saturated aliphatic hydrocarbon resin (for example, Alcon P125).

[0049] The number average molecular weight of the tackifier resin is preferably 500 or more, more preferably 700 or more, and preferably 2,000 or less, more preferably 1,500 or less, and even more preferably 1,000 or less. The number average molecular weight is measured by gel permeation chromatography (GPC) (polystyrene equivalent).

[0050] (rubber) When rubber is used as component (A), the rubber may be either a diene rubber or a non-diene rubber. Examples of rubber include butyl rubber (IIR), isoprene rubber (IR), butadiene rubber (BR), a rubbery copolymer of carboxylated styrene and butadiene (XSBR), a rubbery copolymer of chlorinated isobutylene and isoprene (CIIR), and a rubbery copolymer of brominated isobutylene and isoprene (BIIR). Among these, butyl rubber, isoprene rubber, and butadiene rubber are preferred, and butyl rubber is more preferred.

[0051] From the viewpoint of further improving the adhesive properties, adhesive wet heat resistance, etc. of the adhesive composition, the rubber comprises at least one selected from rubber having an acid anhydride group (i.e., a carbonyloxycarbonyl group (—CO—O—CO—)) and rubber having an epoxy group, and more preferably comprises rubber having an acid anhydride group and rubber having an epoxy group.

[0052] The rubber having an acid anhydride group can be obtained, for example, by graft-modifying a rubber with an unsaturated compound having an acid anhydride group under radical reaction conditions. The unsaturated compound having an acid anhydride group may also be radically copolymerized with an olefin or the like. Examples of the unsaturated compound having an acid anhydride group include succinic anhydride, maleic anhydride, and glutaric anhydride. Only one type of unsaturated compound having an acid anhydride group may be used, or two or more types may be used in combination.

[0053] Similarly, rubber having an epoxy group can be obtained by, for example, graft-modifying rubber with an unsaturated compound having an epoxy group under radical reaction conditions. Alternatively, the unsaturated compound having an epoxy group may be radically copolymerized with rubber having an olefinic double bond. Examples of unsaturated compounds having an epoxy group include glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, and allyl glycidyl ether. Only one type of unsaturated compound having an epoxy group may be used, or two or more types may be used in combination.

[0054] As the rubber having an acid anhydride group, butyl rubber having an acid anhydride group, isoprene rubber having an acid anhydride group, or butadiene rubber having an acid anhydride group is preferred, and butyl rubber having an acid anhydride group is particularly preferred.As the rubber having an epoxy group, butyl rubber having an epoxy group, isoprene rubber having an epoxy group, or butadiene rubber having an epoxy group is preferred, and butyl rubber having an epoxy group is particularly preferred.

[0055] The concentration of the acid anhydride groups in the rubber having the acid anhydride groups is preferably 0.05 to 10 mmol / g, more preferably 0.1 to 5 mmol / g. The concentration of the acid anhydride groups is determined from the acid value, which is defined as the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of rubber, according to JIS K 2501.

[0056] The concentration of epoxy groups in the rubber having epoxy groups is preferably 0.05 to 10 mmol / g, more preferably 0.1 to 5 mmol / g. The epoxy group concentration is determined from the epoxy equivalent weight obtained in accordance with JIS K 7236-1995.

[0057] From the viewpoints of good coatability of the adhesive composition varnish and good compatibility between the rubber and other components, the number average molecular weight of the rubber is preferably 1,000,000 or less, more preferably 750,000 or less, even more preferably 500,000 or less, and particularly preferably 400,000 or less. On the other hand, from the viewpoint of preventing cissing during application of the sealing composition varnish, the number average molecular weight of the rubber is preferably 2,000 or more, more preferably 10,000 or more, even more preferably 30,000 or more, and particularly preferably 50,000 or more. This number average molecular weight is measured by gel permeation chromatography (GPC) (polystyrene equivalent).

[0058] There are no particular limitations on the rubber content. From the viewpoint of good coatability of the adhesive composition varnish, when rubber is used, the content is preferably 80% by mass or less, more preferably 75% by mass or less, even more preferably 70% by mass or less, even more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less, relative to 100% by mass of the nonvolatile content of the adhesive composition. The rubber content is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, even more preferably 10% by mass or more, particularly preferably 15% by mass or more, and most preferably 20% by mass or more, relative to 100% by mass of the nonvolatile content of the adhesive composition.

[0059] (Preferred embodiment) Preferred embodiments of the present invention regarding component (A) will be explained below in order. In one embodiment of the present invention, component (A) preferably contains an olefin-based resin, more preferably contains an olefin-based resin and a tackifier resin. In another embodiment of the present invention, component (A) preferably contains a rubber such as butyl rubber, isoprene rubber, or butadiene rubber, more preferably contains butyl rubber. In another embodiment of the present invention, component (A) preferably contains a rubber and a tackifier resin.

[0060] When component (A) contains an olefin resin having an acid anhydride group and / or a rubber having an acid anhydride group, the amount of the olefin resin having an acid anhydride group and / or the rubber having an acid anhydride group relative to the total amount of component (A) is preferably 1 to 70 mass%, more preferably 10 to 50 mass%. When component (A) contains an olefin resin having an epoxy group and / or a rubber having an epoxy group, the amount of the olefin resin having an epoxy group and / or the rubber having an epoxy group relative to the total amount of component (A) is preferably 1 to 70 mass%, more preferably 10 to 50 mass%.

[0061] From the viewpoint of further improving the moisture resistance and the like of the adhesive composition, the present invention is preferably an embodiment that satisfies at least one of the following (a) to (d). (a) Component (A) contains an olefin resin having an acid anhydride group and an olefin resin having an epoxy group. (b) Component (A) contains a rubber having an acid anhydride group and a rubber having an epoxy group. (c) Component (A) contains an olefin resin having an acid anhydride group and a rubber having an epoxy group. (d) Component (A) contains a rubber having an acid anhydride group and an olefin resin having an epoxy group.

[0062] In the above embodiments (a) to (d), component (A) can form a crosslinked structure by reacting the acid anhydride group and the epoxy group upon heating. Therefore, an adhesive layer with improved moisture resistance can be formed from the adhesive composition of the present invention. While the crosslinked structure can be formed when forming the adhesive layer using the adhesive composition, it is preferable to form the crosslinked structure in the adhesive layer formed on the support during the production of the adhesive sheet.

[0063] The ratio of the olefin resin having an acid anhydride group and / or the rubber having an acid anhydride group to the olefin resin having an epoxy group and / or the rubber having an epoxy group is not particularly limited as long as an appropriate crosslinked structure can be formed, but the molar ratio of the epoxy group to the acid anhydride group (epoxy group:acid anhydride group) is preferably 100:10 to 100:200, more preferably 100:50 to 100:150, and particularly preferably 100:90 to 100:110.

[0064] In one embodiment of the present invention, component (A) is preferably (i) butyl rubber, (ii) a mixture of butyl rubber having an acid anhydride group and butyl rubber having an epoxy group, or (iii) a mixture of butyl rubber, butyl rubber having an acid anhydride group and butyl rubber having an epoxy group.

[0065] In the present invention, when an olefin resin and a rubber are used in combination as component (A), the blending ratio of the two (olefin resin / rubber) is preferably 1 / 99 to 50 / 50, more preferably 10 / 90 to 45 / 55, by mass ratio.

[0066] In one embodiment of the present invention, component (A) preferably contains at least one selected from an olefin resin and an epoxy resin, more preferably an olefin resin or an epoxy resin. By using such component (A), the adhesive composition can be made to have low moisture permeability, suppressed outgassing, and superior transparency.

[0067] The content of component (A) is preferably 25% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, relative to 100% by mass of the nonvolatile content of the adhesive composition, and is preferably 95% by mass or less, more preferably 93% by mass or less, even more preferably 90% by mass or less.

[0068] <(B) Layered clay minerals> One of the features of the adhesive composition of the present invention is that it contains a layered clay mineral as component (B). By using the layered clay mineral, it is possible to improve the light absorption in the wavelength range of 300 to 430 nm while maintaining the transparency of the adhesive layer obtained from the adhesive composition. Component (B) may be used alone or in combination of two or more types. In addition, the layered clay mineral may be a processed layered clay mineral (e.g., semi-calcined hydrotalcite, calcined hydrotalcite, etc.) as described below, or may be an artificial product.

[0069] Examples of layered clay minerals include hydrotalcite and layered silicate minerals, which will be described below in order.

[0070] (hydrotalcite) Hydrotalcite can be classified into uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite.

[0071] Uncalcined hydrotalcite is, for example, natural hydrotalcite (MgAl(OH) 16 It is a metal hydroxide with a layered crystal structure, such as the basic skeleton layer [Mg 1-X Al X (OH)2] X+ and the intermediate layer [(CO3) X / 2 mH2O] X- The uncalcined hydrotalcite of the present invention is a concept that includes hydrotalcite-like compounds such as synthetic hydrotalcite. Examples of hydrotalcite-like compounds include those represented by the following formula (I) and formula (II).

[0072] [M 2+ 1-x M 3+ x (OH)2] x+ ·[(A n- ) x / n ·mH2O] x- (I) (where M 2+ represents divalent metal ions such as Mg 2+ , Zn 2+ , M 3+ represents trivalent metal ions such as Al 3+ , Fe 3+ , A n- represents an n-valent anion such as CO3 2- , Cl - , NO3 - , 0 < x < 1, 0 ≤ m < 1, and n is a positive number.) In formula (I), M 2+ is preferably Mg 2+ , M 3+ is preferably Al 3+ , and A n- is preferably CO3 2- .

[0073] M 2+ x Al2(OH) 2x+6-nz (A n- ) z ·mH2O (II) (where M 2+ represents divalent metal ions such as Mg 2+ , Zn 2+ , A n- represents an n-valent anion such as CO3 2- , Cl - , NO3 - , x is a positive number of 2 or more, z is a positive number of 2 or less, m is a positive number, and n is a positive number.) In formula (II), M 2+ is preferably Mg 2+ , and A n- is preferably CO3 2- .<00003​ Semi-calcined hydrotalcite refers to a metal hydroxide having a layered crystal structure in which the amount of interlayer water is reduced or eliminated, and is obtained by calcining uncalcined hydrotalcite. When explained using a compositional formula, "interlayer water" refers to "H2O" described in the compositional formula of the above-mentioned uncalcined natural hydrotalcite and hydrotalcite-like compounds.

[0075] On the other hand, calcined hydrotalcite is obtained by calcining uncalcined or semi-calcined hydrotalcite, and refers to a metal oxide with an amorphous structure in which not only interlayer water (HO) but also hydroxyl groups (OH) have disappeared through condensation dehydration.

[0076] Uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished by their saturated water absorption. The saturated water absorption of semi-calcined hydrotalcite is 1% by mass or more and less than 20% by mass. On the other hand, the saturated water absorption of uncalcined hydrotalcite is less than 1% by mass, and the saturated water absorption of calcined hydrotalcite is 20% by mass or more.

[0077] The "saturated water absorption" in the present invention refers to the rate of mass increase relative to the initial mass when 1.5 g of uncalcined hydrotalcite, semi-calcined hydrotalcite, or calcined hydrotalcite is weighed out on a balance, the initial mass is measured, and the resulting mass is then left to stand for 200 hours in a small environmental test chamber (SH-222 manufactured by Espec Corporation) set at atmospheric pressure, 60°C, and 90% RH (relative humidity), and is calculated using the following formula (i): Saturated water absorption rate (mass%) = 100 × (mass after moisture absorption – initial mass) / initial mass (i) It can be found by:

[0078] The saturated water absorption of the semi-calcined hydrotalcite is preferably 3% by mass or more and less than 20% by mass, and more preferably 5% by mass or more and less than 20% by mass.

[0079] Furthermore, uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished by the rate of weight loss on heat measured by thermogravimetric analysis. The rate of weight loss on heat of semi-calcined hydrotalcite at 280°C is less than 15% by mass, and its rate of weight loss on heat at 380°C is 12% by mass or more. On the other hand, the rate of weight loss on heat of uncalcined hydrotalcite at 280°C is 15% by mass or more, and the rate of weight loss on heat of calcined hydrotalcite at 380°C is less than 12% by mass.

[0080] Thermogravimetric analysis can be performed using a Hitachi High-Tech Science TG / DTA EXSTAR6300 by weighing 5 mg of hydrotalcite into an aluminum sample pan, leaving the pan open without a lid, in a nitrogen atmosphere with a flow rate of 200 mL / min, and heating from 30°C to 550°C at a rate of 10°C / min. The thermal weight loss rate can be calculated using the following formula (ii): Thermogravimetric reduction rate (mass%) = 100 × (mass before heating - mass when reaching the specified temperature) / mass before heating (ii) It can be found by:

[0081] Uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished by the peaks and relative intensity ratios measured by powder X-ray diffraction. Semi-calcined hydrotalcite exhibits a split peak or a peak with a shoulder formed by combining two peaks in powder X-ray diffraction at 2θ of approximately 8 to 18°. The relative intensity ratio (low-angle diffraction intensity / high-angle diffraction intensity) between the diffraction intensity of the peak or shoulder appearing on the low-angle side (= low-angle diffraction intensity) and the diffraction intensity of the peak or shoulder appearing on the high-angle side (= high-angle diffraction intensity) is 0.001 to 1,000. On the other hand, uncalcined hydrotalcite has only one peak near 8 to 18°, or the relative intensity ratio between the diffraction intensity of the peak or shoulder appearing on the low-angle side and the peak or shoulder appearing on the high-angle side falls outside the aforementioned range. Calcined hydrotalcite does not have a characteristic peak in the 8 to 18° region, but has a characteristic peak at 43°. Powder X-ray diffraction measurements were performed using a powder X-ray diffractometer (PANalytical, Empyrean) with a CuKα (1.5405 Å) anticathode, voltage: 45 V, current: 40 mA, sampling width: 0.0260°, scan rate: 0.0657° / s, and diffraction angle range (2θ): 5.0131–79.9711°. Peak search was performed using the peak search function of the software provided with the diffractometer under the following conditions: minimum significance: 0.50, minimum peak tip: 0.01°, maximum peak tip: 1.00°, peak base width: 2.00°, and method: minimum second derivative.

[0082] The BET specific surface area of ​​hydrotalcite (especially semi-calcined hydrotalcite) is 1 to 250 m 2 / g is preferred, and 5 to 200m 2 The BET specific surface area of ​​hydrotalcite can be calculated according to the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM Model 1210, manufactured by Mountech Co., Ltd.) and then using the BET multipoint method.

[0083] The average particle size of the hydrotalcite (particularly semi-calcined hydrotalcite) is preferably 1 to 1,000 nm, more preferably 10 to 800 nm. The average particle size of the hydrotalcite is the median size of the particle size distribution determined on a volume basis by laser diffraction / scattering particle size distribution measurement (JIS Z 8825).

[0084] Hydrotalcite (particularly semi-calcined hydrotalcite) can be used after surface treatment with a surface treatment agent. Examples of the surface treatment agent that can be used for the surface treatment include higher fatty acids, alkylsilanes, and silane coupling agents, with higher fatty acids and alkylsilanes being particularly preferred. One or more types of surface treatment agents can be used.

[0085] Examples of higher fatty acids include higher fatty acids having 14 or more carbon atoms, such as stearic acid, montanic acid, myristic acid, and palmitic acid, and among these, stearic acid is preferred. These may be used alone or in combination of two or more.

[0086] Examples of alkylsilanes include methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, dimethyldimethoxysilane, octyltriethoxysilane, n-octadecyldimethyl(3-(trimethoxysilyl)propyl)ammonium chloride, etc. These may be used alone or in combination.

[0087] Examples of the silane coupling agent include epoxy-based silane coupling agents such as 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyl(dimethoxy)methylsilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; mercapto-based silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 11-mercaptoundecyltrimethoxysilane; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, N-phenyl-3-aminopropyltrimethoxysilane, N-methylaminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane. Examples of suitable silane coupling agents include amino-based silane coupling agents such as aminopropyldimethoxymethylsilane; ureido-based silane coupling agents such as 3-ureidopropyltriethoxysilane; vinyl-based silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinylmethyldiethoxysilane; styryl-based silane coupling agents such as p-styryltrimethoxysilane; acrylate-based silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane; isocyanate-based silane coupling agents such as 3-isocyanatepropyltrimethoxysilane; sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)disulfide and bis(triethoxysilylpropyl)tetrasulfide; phenyltrimethoxysilane, methacryloxypropyltrimethoxysilane, imidazole silane, and triazine silane. These may be used alone or in combination.

[0088] Surface treatment of hydrotalcite (particularly semi-calcined hydrotalcite) can be carried out, for example, by adding and spraying a surface treatment agent to untreated hydrotalcite while stirring and dispersing it in a mixer at room temperature and stirring for 5 to 60 minutes. Known mixers can be used, including blenders such as V blenders, ribbon blenders, and bubble cone blenders; mixers such as Henschel mixers and concrete mixers; ball mills; and cutter mills. Alternatively, when pulverizing hydrotalcite using a ball mill or the like, the above-mentioned higher fatty acids, alkylsilanes, or silane coupling agents can be added to perform surface treatment. The amount of surface treatment agent used varies depending on the type of hydrotalcite or the type of surface treatment agent, but is preferably 1 to 10 parts by mass per 100 parts by mass of untreated hydrotalcite. In the present invention, surface-treated hydrotalcite is also encompassed within the "hydrotalcite" of the present invention.

[0089] When calcined hydrotalcite and / or semi-calcined hydrotalcite is used as component (B), these have excellent moisture absorption properties, and therefore the moisture blocking properties of the resulting adhesive layer are improved.

[0090] Examples of semi-calcined hydrotalcites include "DHT-4C" (manufactured by Kyowa Chemical Industry Co., Ltd., average particle size: 400 nm) and "DHT-4A-2" (manufactured by Kyowa Chemical Industry Co., Ltd., average particle size: 400 nm). Examples of calcined hydrotalcites include "KW-2200" (manufactured by Kyowa Chemical Industry Co., Ltd., average particle size: 400 nm). Examples of uncalcined hydrotalcites include "DHT-4A" (manufactured by Kyowa Chemical Industry Co., Ltd., average particle size: 400 nm).

[0091] (layered silicate mineral) Layered silicate minerals are also generally called phyllosilicates. Layered silicate minerals can be used alone or in combination of two or more. The layered silicate minerals may be natural or synthetic. It is preferable to use a highly pure layered silicate mineral with a regularly stacked crystal structure in the c-axis direction. However, so-called mixed layered minerals, in which the crystal period is disrupted and multiple types of crystal structures are mixed, may also be used.

[0092] Examples of layered silicate minerals include smectite, kaolinite, halloysite, talc, mica, etc. Among these, mica is preferred.

[0093] Smectites have the general formula: X 0.2~0.6 Y 2~3 Z4O 10 Smectites are expressed as (OH)₂·nH₂O (wherein X is at least one selected from K, Na, 1 / 2Ca, and 1 / 2Mg; Y is at least one selected from Mg, Fe, Mn, Ni, Zn, Li, Al, and Cr; and Z is at least one selected from Si and Al. H₂O represents water molecules bonded to interlayer ions. n is an integer that can vary significantly depending on the interlayer ions and relative humidity.) and can be natural or synthetic. Examples of smectite include hectorite, montmorillonite, beidellite, nontronite, saponite, iron saponite, sauconite, stevensite, bentonite, or their substitution products, derivatives, or mixtures. Among these, hectorite and montmorillonite are preferred.

[0094] Commercially available layered silicate minerals can be used, such as "Sumecton STN" and "Sumecton SAN" (organically modified hectorite) manufactured by Kunimine Industries Co., Ltd., "Orben M" (organically modified montmorillonite) manufactured by Shiraishi Kogyo Co., Ltd., "Esben NX" (organically modified montmorillonite) manufactured by Hojun Co., Ltd., and "Benton Series" (organically modified montmorillonite) manufactured by Toshin Kasei Co., Ltd.

[0095] The average particle size of the layered silicate mineral is preferably 1 nm to 100 μm, more preferably 5 nm to 50 μm, and even more preferably 10 nm to 10 μm. The average particle size of the layered silicate mineral is the median size of a particle size distribution determined on a volume basis by laser diffraction / scattering particle size distribution measurement (JIS Z 8825).

[0096] (Preferred embodiment) Hereinafter, preferred embodiments of the present invention regarding component (B) will be described in order. Component (B) preferably contains at least one selected from hydrotalcite and layered silicate minerals, more preferably contains hydrotalcite, even more preferably contains semi-calcined hydrotalcite, and particularly preferably consists of semi-calcined hydrotalcite. The hydrotalcite and layered silicate minerals in this embodiment are as described above.

[0097] From the viewpoint of sufficiently suppressing a decrease in the light absorption ability of the adhesive layer in the short wavelength region, the content of component (B) is preferably 1% by mass or more, more preferably 3% by mass or more, based on 100% by mass of the nonvolatile content of the adhesive composition. On the other hand, from the viewpoint of improving the transparency of the adhesive layer, the content of component (B) is preferably 60% by mass or less, more preferably 55% by mass or less, based on 100% by mass of the nonvolatile content of the adhesive composition.

[0098] <(C) Compounds having a maximum absorption wavelength in the wavelength range of 300 to 430 nm> One of the features of the adhesive composition of the present invention is that it contains, as component (C), a compound having a maximum absorption wavelength (λmax) in the wavelength range of 300 to 430 nm. Component (C) may be used alone or in combination of two or more types.

[0099] The maximum absorption wavelength (λmax) of component (C) can be determined by preparing a solution of component (C) at a concentration such that the absorbance at the maximum absorption wavelength in the optical absorption spectrum is 1.0 and measuring the optical absorption spectrum of the solution. Examples of solvents for preparing a solution of component (C) include chloroform and toluene.

[0100] The maximum absorption wavelength (λmax) of component (C) is preferably 320 to 430 nm, more preferably 350 to 430 nm.

[0101] Component (C) may be treated as an ultraviolet absorber. Known ultraviolet absorbers having a maximum absorption wavelength in the wavelength range of 300 to 430 nm can be used as component (C) of the present invention.

[0102] Examples of component (C) include curcuminoid compounds, benzotriazole compounds, benzophenone compounds, triazine compounds, benzoate ester compounds, cyanoacrylate compounds, salicylate ester compounds, azomethine compounds, indole compounds, cinnamic acid compounds, pyrimidine compounds, porphyrin compounds, cyanoacrylate compounds, oxybenzophenone compounds, polyphenol compounds, etc. Component (C) is preferably at least one selected from curcuminoid compounds, benzotriazole compounds, and benzophenone compounds.

[0103] Examples of curcuminoid compounds include 1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (Sanwa Chemical Co., Ltd., curcumin, λmax=420 nm) and 1,7-bis(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (Sanwa Chemical Co., Ltd., HPH, λmax=416 nm).

[0104] Examples of benzotriazole compounds include 2-(2-hydroxy-5-methylphenyl)benzotriazole (manufactured by BASF Japan Ltd., Tinuvin P, λmax=341 nm), 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole (manufactured by BASF Japan Ltd., Tinuvin 234, λmax=343 nm), 2-(3-tert-butyl-5-methyl-2-hydroxyphenyl)5-chlorobenzotriazole (manufactured by BASF Japan Ltd., Tinuvin 326, λmax=353 nm), 2-(2-hydroxy-5-tert-octyl)benzotriazole (manufactured by BASF Japan Ltd., Tinuvin 326, λmax=353 nm), and 2-(2-hydroxy-5-tert-octyl)benzotriazole (manufactured by BASF Japan Ltd., Tinuvin 326, λmax=353 nm). phenyl)benzotriazole (BASF Japan, Tinuvin 329, λmax = 343 nm), 2,2'-methylenebis[6-(benzotriazol-2-yl)-4-tert-octylphenol] (BASF Japan, Tinuvin 360, λmax = 349 nm), 5-chloro-2-[3-(tert-butyl)-2-hydroxy-5-methylphenyl]-2H-benzotriazole (ADEKA, Adekastab LA-36, λmax=355nm), 2-(2-hydroxy-5'-methylphenyl)benzotriazole (Johoku Chemical Co., Ltd., JF-77, λmax=341nm), 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole (Johoku Chemical Co., Ltd., JF-80, λmax=306nm), 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole (Johoku Chemical Co., Ltd., JF-83, λmax=343nm), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol] (Johoku Chemical Co., Ltd., JF-832, λmax=349nm), 2-(2,Examples of such an oxidizing agent include 2-(4-dihydroxyphenyl)-2H-benzotriazole (manufactured by Daiwa Chemical Industry Co., Ltd., DAINSORB T-0, λmax=345 nm), 2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole (manufactured by Daiwa Chemical Industry Co., Ltd., DAINSORB T-7, λmax=345 nm), 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole (manufactured by Daiwa Chemical Industry Co., Ltd., UV-326, λmax=353 nm), and 2-(3-tert-butyl-2-dihydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole (manufactured by Shipro Chemical Industry Co., Ltd., SEESORB 703, λmax=354 nm).

[0105] Examples of benzophenone compounds include 2,2',4,4'-tetrahydroxybenzophenone (Daiwa Chemical Industry Co., Ltd., DAINSORB P-6, λmax=354 nm), 2-(3-t-butyl-2-dihydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole (Shipro Chemical Industry Co., Ltd., SEESORB 106, λmax=354 nm), and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (Shipro Chemical Industry Co., Ltd., SEESORB 107, λmax=356 ​​nm).

[0106] Examples of triazine compounds include 2-[4-(octyl-2-methylethanoate)oxy-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)]-1,3,5-triazine (manufactured by BASF Japan Ltd., Tinuvin 479, λmax=322 nm), 2-[4-(2-hydroxy-3-dodecyloxy-propyl)oxy-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)-1,3,5-triazine (manufactured by BASF Japan Ltd., Tinuvin 400, λmax=336 nm), and 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (manufactured by BASF Japan Ltd., Tinuvin 460, λmax=346 nm).

[0107] An example of a benzoate compound is diethylaminohydroxybenzoylhexyl benzoate (manufactured by BASF Japan Ltd., Uvinul A Plus, λmax=354 nm).

[0108] Examples of cyanoacrylate compounds include ethyl-2-cyano-3,3-diphenylacrylate (manufactured by BASF Japan Ltd., Uvinul 3035, λmax=302 nm), 2-ethylhexyl-2-cyano-3,3-diphenylacrylate (manufactured by BASF Japan Ltd., Uvinul 3039, λmax=303 nm), and 2,4-dihydroxybenzophenone (manufactured by BASF Japan Ltd., Uvinul 3030, λmax=308 nm).

[0109] Examples of salicylate compounds include phenyl salicylate (λmax=310 nm) and octyl salicylate (λmax=301 nm). An example of an azomethine compound is BONASORB UA-3701 (trade name, λmax=378 nm, half width: 60 nm, manufactured by Orient Chemical Industries Co., Ltd.).

[0110] Examples of indole compounds include BONASORB UA-3911 (trade name, λmax=395 nm, manufactured by Orient Chemical Industries Co., Ltd.) and BONASORB UA-3912 (trade name, λmax=390 nm, manufactured by Orient Chemical Industries Co., Ltd.).

[0111] Examples of cinnamic acid compounds include ethylhexyl methoxycinnamate (Uvinul MC80N, manufactured by BASF Japan Ltd., λmax=310 nm), octyl p-methoxycinnamate (λmax=308 nm), glyceryl di-para-methoxycinnamate mono-2-ethylhexanoate (λmax=312 nm), Parsol MCX (trade name, λmax=311 nm, manufactured by DSM Nutrition Japan), and NeoHeliopan AV (trade name, λmax=311 nm, manufactured by Symrise).

[0112] An example of a pyrimidine compound is FDB-009 (trade name, manufactured by Yamada Chemical Industry Co., Ltd., λmax=402 nm). An example of a porphyrin compound is FDB-001 (trade name, manufactured by Yamada Chemical Industry Co., Ltd., λmax=420 nm).

[0113] To ensure that the adhesive layer formed from the adhesive composition has sufficient light absorption in the short wavelength region, the content of component (C) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, based on 100% by mass of the nonvolatile content of the adhesive composition. On the other hand, to ensure good transparency of the adhesive layer and to prevent problems such as crystallization or leakage of component (C) and discoloration of the adhesive layer, the content of component (C) is preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 10% by mass or less, based on 100% by mass of the nonvolatile content of the adhesive composition.

[0114] <Other ingredients> The adhesive composition of the present invention may contain other components different from components (A) to (C) as long as the effects of the present invention are not impaired. These other components may be used singly or in combination of two or more. Examples of such other components include curing agents, curing accelerators, organic solvents, softeners such as mineral oil-based softeners, vegetable oil-based softeners, subfactines, fatty acids, fatty acid salts, and synthetic oils, organic fillers such as rubber particles, silicone powder, nylon powder, and fluororesin powder, antifoaming agents or leveling agents, adhesion promoters, thickeners such as Orben and Bentone, antioxidants, heat stabilizers, and light stabilizers.

[0115] When at least one selected from a thermosetting resin (e.g., an epoxy resin), a thermoplastic resin having an epoxy group (e.g., an olefin resin having an epoxy group), and a rubber having an epoxy group is used as component (A), the adhesive composition of the present invention preferably contains a curing agent. The curing agent may be used alone or in combination of two or more.

[0116] The curing agent is not particularly limited, and known curing agents can be used. Examples of the curing agent include tertiary amine compounds, primary or secondary amine compounds, ionic liquids, acid anhydride compounds, imidazole compounds, dimethylurea compounds, amine adduct compounds, organic acid dihydrazide compounds, organic phosphine compounds, and dicyandiamide compounds. The curing agent is preferably a tertiary amine compound.

[0117] The adhesive composition of the present invention may contain a curing accelerator. Only one type of curing accelerator may be used, or two or more types may be used in combination. There are no particular limitations on the curing accelerator, and known accelerators can be used. Examples of curing accelerators include tertiary amine compounds, imidazole compounds, dimethylurea compounds, amine adduct compounds, and organic phosphine compounds. The curing accelerator is preferably at least one selected from tertiary amine compounds, imidazole compounds, and dimethylurea compounds.

[0118] Examples of tertiary amine compounds that serve as curing agents or curing accelerators include DBN (1,5-diazabicyclo[4.3.0]non-5-ene), DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), DBU 2-ethylhexanoate, DBU phenolate, DBU p-toluenesulfonate, U-CAT SA 102 (manufactured by San-Apro: DBU octylate), DBU formate and other DBU-organic acid salts, and 2,4,6-tris(dimethylaminomethyl)phenol (TAP).

[0119] Examples of primary or secondary amine compounds that serve as curing agents include aliphatic amines such as diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, 1,3-bisaminomethylcyclohexane, dipropylenediamine, diethylaminopropylamine, bis(4-aminocyclohexyl)methane, norbornenediamine, and 1,2-diaminocyclohexane; alicyclic amines such as N-aminoethylpiperazine and 1,4-bis(3-aminopropyl)piperazine; and aromatic amines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and diethyltoluenediamine. Commercially available primary or secondary amine compounds include Kayahard AA (manufactured by Nippon Kayaku Co., Ltd.: 4,4'-diamino-3,3'-dimethyldiphenylmethane).

[0120] Examples of ionic liquids that serve as curing agents include 1-butyl-3-methylimidazolium lactate, tetrabutylphosphonium-2-pyrrolidone-5-carboxylate, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium trifluoroacetate, tetrabutylphosphonium α-lipoate, tetrabutylphosphonium formate, tetrabutylphosphonium lactate, bis(tetrabutylphosphonium) tartrate, tetrabutylphosphonium hippurate, tetrabutylphosphonium N-methylhippurate, benzoyl-DL-alanine tetrabutylphosphonium salt, N-acetylphenylalanine tetrabutylphosphonium salt, 2,6-di-tert-butylphenol tetrabutylphosphonium salt, and monotetrabutyl L-aspartate. Phosphonium salts, glycine tetrabutylphosphonium salt, 1-ethyl-3-methylimidazolium lactate, 1-ethyl-3-methylimidazolium acetate, formic acid 1-ethyl-3-methylimidazolium salt, hippuric acid 1-ethyl-3-methylimidazolium salt, N-methylhippuric acid 1-ethyl-3-methylimidazolium salt, tartrate bis(1-ethyl-3-methylimidazolium) salt, N-acetylglycine 1-ethyl-3-methylimidazolium salt are preferred, and examples thereof include tetrabutylphosphonium decanoate, N-acetylglycine tetrabutylphosphonium salt, 1-ethyl-3-methylimidazolium acetate, formic acid 1-ethyl-3-methylimidazolium salt, hippuric acid 1-ethyl-3-methylimidazolium salt, N-methylhippuric acid 1-ethyl-3-methylimidazolium salt, and the like.

[0121] Examples of acid anhydride compounds that serve as curing agents include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, dodecenylsuccinic anhydride, etc. Examples of commercially available acid anhydride compounds include Rikacid TH, TH-1A, HH, MH, MH-700, and MH-700G (all manufactured by New Japan Chemical Co., Ltd.).

[0122] Examples of the imidazole compound that is a curing agent or a curing accelerator include 1H-imidazole, 2-methyl-imidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methyl-imidazole, 2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6-(2'-undecylimidazolyl-(1'))-ethyl-s-triazine, 2-phenyl-4,5-bis(hydroxymethyl)-imidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-phenyl-imidazole, 2-dodecyl-imidazole, imidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6-(2'-methylimidazolyl-(1')-ethyl-s-triazine, 2,4-diamino-6-(2'-methylimidazolyl-(1'))-ethyl-s-triazine isocyanuric acid adduct, etc. Commercially available imidazole compounds include, for example, Curesol 2MZ, 2P4MZ, 2E4MZ, 2E4MZ-CN, C11Z, C11Z-CN, C11Z-CNS, C11Z-A, 2PHZ, 1B2MZ, 1B2PZ, 2PZ, C17Z, 1.2DMZ, 2P4MHZ-PW, 2MZ-A, and 2MA-OK (all manufactured by Shikoku Chemicals Corporation).

[0123] Examples of dimethylurea compounds that are curing agents or curing accelerators include aromatic dimethylureas such as DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and U-CAT3512T (manufactured by San-Apro Co., Ltd.), and aliphatic dimethylureas such as U-CAT3503N (manufactured by San-Apro Co., Ltd.) Among these, aromatic dimethylureas are preferred from the viewpoint of curability.

[0124] Examples of amine adduct compounds that are curing agents or curing accelerators include epoxy adduct compounds obtained by stopping the addition reaction of a tertiary amine to an epoxy resin midway. Commercially available amine adduct compounds include Amicure PN-23, Amicure MY-24, Amicure PN-D, Amicure MY-D, Amicure PN-H, Amicure MY-H, Amicure PN-31, Amicure PN-40, and Amicure PN-40J (all manufactured by Ajinomoto Fine-Techno Co., Inc.).

[0125] Examples of organic acid dihydrazide compounds that serve as curing agents include Amicure VDH-J, Amicure UDH, and Amicure LDH (all manufactured by Ajinomoto Fine-Techno Co., Inc.).

[0126] Examples of organic phosphine compounds that are curing agents or curing accelerators include triphenylphosphine, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tri-tert-butylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, triphenylphosphine triphenylborane, etc. Examples of commercially available organic phosphine compounds include TPP, TPP-MK, TPP-K, TTBuP-K, TPP-SCN, and TPP-S (manufactured by Hokko Chemical Industry Co., Ltd.).

[0127] An example of a dicyandiamide compound that serves as a curing agent is dicyandiamide. Commercially available dicyandiamide products include DICY7 and DICY15 (both manufactured by Mitsubishi Chemical Corporation), which are finely ground dicyandiamide products.

[0128] When a thermosetting resin (particularly an epoxy resin) is used as component (A) in the adhesive composition of the present invention, the content of the curing agent is preferably 0.1 to 40 mass%, more preferably 0.5 to 38 mass%, and even more preferably 1 to 25 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition, from the viewpoint of the balance between curability and storage stability. When the pressure-sensitive adhesive composition of the present invention contains a curing accelerator, the content thereof is preferably 0.05 to 10 mass%, more preferably 0.1 to 8 mass%, and even more preferably 0.5 to 5 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition, from the same viewpoint. When a thermosetting resin (particularly an epoxy resin) is used, it is preferable to use a combination of a curing agent and a curing accelerator.

[0129] When the adhesive composition of the present invention uses a thermoplastic resin having an epoxy group (particularly an olefin resin having an epoxy group) and / or a rubber having an epoxy group as component (A), the adhesive composition of the present invention preferably contains a curing accelerator. The content of the curing accelerator is preferably 0.01 to 10 mass %, more preferably 0.05 to 5 mass %, relative to 100 mass % of the nonvolatile content of the adhesive composition.

[0130] The adhesive composition of the present invention may contain an organic solvent. The organic solvent may be used alone or in combination. Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (hereinafter also abbreviated as "MEK"), and cyclohexanone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. An adhesive composition containing an organic solvent is sometimes referred to as an adhesive composition varnish. The amount of organic solvent is not particularly limited, but from the viewpoint of coatability, it is preferable to use the organic solvent in an amount such that the viscosity (25°C) of the adhesive composition varnish is 300 to 2000 mPa·s.

[0131] <Production of Adhesive Composition> The adhesive composition of the present invention can be produced by mixing the above-mentioned components (A) to (C) and, if necessary, other components. There are no particular limitations on the mixing means, and mixing can be carried out using known equipment (e.g., kneading rollers, rotary mixers, etc.).

[0132] <Applications of adhesive composition> The adhesive composition of the present invention is preferably used to form an adhesive layer in an optical device. The optical device in the present invention refers to an electronic device related to light, such as an organic EL display device or a solar cell. In particular, the adhesive composition of the present invention can be suitably used to provide an adhesive layer for blocking light such as ultraviolet light in an organic EL display device, where degradation of organic EL elements due to light such as ultraviolet light is a problem. For example, an adhesive layer in an optical device can be formed by applying an adhesive composition varnish to a component of the optical device and drying it.

[0133] <Adhesive sheet> The present invention also provides an adhesive sheet comprising a support and an adhesive layer formed on the support from the adhesive composition of the present invention. The adhesive sheet of the present invention, like the adhesive composition, is preferably used to form an adhesive layer in an optical device. For example, the adhesive sheet can be attached to a component of an optical device, and then the support of the adhesive sheet can be peeled off to form an adhesive layer in the optical device.

[0134] The adhesive sheet of the present invention can be produced, for example, by applying an adhesive composition varnish to a support and drying the resulting coating to form an adhesive layer on the support. From the viewpoint of the balance between light absorption ability in the short wavelength range and transparency, the thickness of the adhesive layer in the adhesive sheet is preferably 10 to 200 μm, more preferably 20 to 180 μm, and even more preferably 30 to 150 μm.

[0135] The support used in the adhesive sheet is not particularly limited, and known supports can be used. Examples of the support include plastic films formed from polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate; polycarbonate; and polyimide. PET film is particularly preferred as a plastic film. The support may also be a metal foil such as aluminum foil, stainless steel foil, or copper foil. The support may be subjected to a matte treatment, corona treatment, or release treatment. Examples of release treatments include release treatments using a silicone resin-based release agent, an alkyd resin-based release agent, or a fluororesin-based release agent. In the present invention, when the support has a release layer, the release layer is also considered to be part of the support. The thickness of the support is not particularly limited, but from the viewpoint of ease of handling, it is preferably 20 to 200 μm, more preferably 20 to 125 μm.

[0136] In the adhesive sheet, the adhesive layer may be protected by a protective film. Protection with a protective film can prevent the adhesion of dust and the like to the surface of the adhesive layer and scratches. The protective film is preferably a plastic film similar to that of the support. The protective film may also be subjected to a matte treatment, corona treatment, release treatment, etc. The thickness of the protective film is not particularly limited, but is usually 1 to 150 μm, preferably 10 to 100 μm.

[0137] <Transparency> The adhesive layer formed from the adhesive composition of the present invention is preferably transparent. This transparency can be evaluated by the total light transmittance of an 80 μm-thick adhesive layer at 650 nm in the visible light range. The total light transmittance of an 80 μm-thick adhesive layer formed from the adhesive composition of the present invention at 650 nm is preferably 80 to 100%, more preferably 85 to 100%.

[0138] <Haze> The adhesive layer formed from the adhesive composition of the present invention preferably has low haze. The haze of an adhesive layer formed from the adhesive composition of the present invention and having a thickness of 80 μm is preferably 30% or less. Haze can be measured by a method in accordance with JIS K 7136.

[0139] <Optical devices> The present invention also provides an optical device having an adhesive layer formed from the adhesive composition. Examples of optical devices include organic electroluminescence (EL) display devices and solar cells, with organic electroluminescence (EL) display devices being preferred. [Example]

[0140] The present invention will be described in more detail below by showing examples, but the present invention is not limited to these examples.

[0141] <Evaluation of short wavelength light absorption and transparency> In order to evaluate the light absorption ability and transparency in the short wavelength region of the adhesive layer (i.e., the adhesive layer formed from the adhesive composition) of the adhesive sheets produced in the examples and comparative examples, the total light transmittance at wavelengths of 380 nm and 400 nm, and the total light transmittance at a wavelength of 650 nm were measured.

[0142] (1) Preparation of evaluation samples The adhesive sheets (adhesive layer thickness: 80 μm) prepared in the Examples and Comparative Examples were cut to a length of 70 mm x width of 25 mm. The cut sheets were then laminated onto glass plates (76 mm long, 26 mm wide, and 1.2 mm thick microslide glass, Matsunami Glass Industrial Co., Ltd. white slide glass S1112, polished edge No. 2) using a batch vacuum laminator (Nichigo-Morton, V-160). The lamination conditions were a temperature of 80°C, a depressurization time of 30 seconds, followed by a pressure of 0.3 MPa for 30 seconds. The polyethylene terephthalate (PET) film on the adhesive sheet was then peeled off, and the same glass plate as above was laminated onto the exposed adhesive layer to prepare evaluation samples (laminates).

[0143] (2) Evaluation of light absorption in the short wavelength range (measurement of total light transmittance at 380 nm and 400 nm) A fiber spectrophotometer (MCPD-7700, model 311C, manufactured by Otsuka Electronics Co., Ltd., external light source unit: halogen lamp MC-2564 (24V, 150W specification)) equipped with an 80mm φ integrating sphere (model SRS-99-010, reflectance 99%) was used, with the distance between the integrating sphere and the evaluation sample set to 0mm and the distance between the light source and the evaluation sample set to 48mm, and the light transmittance spectrum of the obtained evaluation sample was measured. The same glass plate as above was used as a reference. The total light transmittance at 380nm and 400nm was calculated from the obtained light transmittance spectrum.

[0144] (3) Transparency evaluation (measurement of total light transmittance at a wavelength of 650 nm) From the light transmittance spectrum obtained by the above method, the total light transmittance at a wavelength of 650 nm was determined.

[0145] The raw materials used in the examples and comparative examples are as follows. (A) Organic binder T-YP341 (Seiko PMC): 20% by mass toluene solution of glycidyl methacrylate-modified propylene-butene copolymer (propylene unit / butene unit: 71% by mass / 29% by mass, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 155,000) HV-1900 (JXTG Nippon Oil & Energy Corporation): Polybutene (number average molecular weight: 2,900) HV-300M (Toho Chemical Industry Co., Ltd.): Maleic anhydride-modified liquid polybutene (acid anhydride group concentration: 0.77 mmol / g, number average molecular weight: 2,100) Alcon P125 (Arakawa Chemical Co., Ltd.): tackifying resin (saturated aliphatic hydrocarbon resin, softening point: 125°C, number average molecular weight: 750) YX8000 (Mitsubishi Chemical Corporation): Liquid hydrogenated bisphenol A epoxy resin (epoxy equivalent: approximately 205, weight average molecular weight: 410) YX8040 (Mitsubishi Chemical Corporation): Solid hydrogenated bisphenol A epoxy resin (epoxy equivalent: approximately 1000, weight average molecular weight: 3,000) YX7200B35 (Mitsubishi Chemical Corporation): Phenoxy resin solution (solvent: MEK, non-volatile content: 35% by mass, number average molecular weight of phenoxy resin: 10,000, weight average molecular weight of phenoxy resin: 30,000)

[0146] (B) Layered clay minerals Semi-calcined hydrotalcite (saturated water absorption: 17% by mass, thermal weight loss at 280°C: 3.6% by mass, thermal weight loss at 380°C: 14.4% by mass, low-angle diffraction intensity / high-angle diffraction intensity in powder X-ray diffraction: 0.6, average particle size: 400 nm, BET specific surface area: 15 m 2 / g, magnesium oxide / aluminum oxide molar ratio: 4.16)

[0147] (C) Compounds with a maximum absorption wavelength in the wavelength range of 300 to 430 nm SEESORB703 (a benzotriazole compound manufactured by Shipro Chemicals): 2-(3-tert-butyl-2-dihydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole (λmax = 354 nm) HPH (a curcuminoid compound manufactured by Sanwa Chemical Co., Ltd.): 1,7-bis(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (λmax=416nm) DAINSORB T-0 (a benzotriazole compound manufactured by Daiwa Chemical Industry Co., Ltd.): 2-(2,4-dihydroxyphenyl)-2H-benzotriazole (λmax = 345 nm) SEESORB107 (a benzophenone compound manufactured by Shipro Chemicals): 2,2-dihydroxy-4,4-dimethoxybenzophenone (λmax=356nm)

[0148] (D) Other ingredients 2,4,6-tris(diaminomethyl)phenol (hereinafter referred to as "TAP"): Curing accelerator Toluene, Ipsol #100 (Idemitsu Kosan): Aromatic mixed solvent Methyl ethyl ketone (MEK) Anon (Sumitomo Chemical Co., Ltd.): Cyclohexanone U-CAT3512T (San-Apro): Curing accelerator N-acetylglycine tetrabutylphosphonium salt: ionic liquid curing agent

[0149] Example 1 A mixture was obtained by mixing 130 parts by mass of a 60% by mass solution of tackifier resin ("Alcon P125" manufactured by Arakawa Chemical Industries, Ltd.) in Ipsol #100 (78 parts by mass of non-volatile content), 35 parts by mass of maleic anhydride-modified liquid polybutene ("HV-300M" manufactured by Toho Chemical Industry Co., Ltd.), 60 parts by mass of polybutene ("HV-1900" manufactured by JXTG Nippon Oil & Energy Corporation), and 100 parts by mass of the semi-calcined hydrotalcite described above as component (B) using a three-roll mill. The resulting mixture was mixed with 200 parts by weight (40 parts by weight) of a 20% by weight toluene solution of glycidyl methacrylate-modified propylene-butene copolymer (T-YP341 manufactured by Seiko PMC), 2.5 parts by weight (0.5 parts by weight) of a 20% by weight toluene solution of TAP, and 14 parts by weight of toluene. 3.3 parts by weight of SEESORB 703 (manufactured by Shipro Kasei Co., Ltd.) were further added as component (C). The resulting mixture was mixed uniformly in a high-speed rotating mixer to obtain an adhesive composition varnish. The resulting varnish was uniformly applied to a polyethylene terephthalate (PET) film treated with a silicone-based release agent using a die coater, and then heated and dried at 130 ° C for 60 minutes to obtain an adhesive sheet with an 80 μm thick adhesive layer.

[0150] In Example 1, the content of component (A) was 67.2 mass%, the content of component (B) was 31.6 mass%, and the content of component (C) was 1.0 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition. Table 1 below shows the results of the total light transmittance measured as described above.

[0151] <Comparative Example 1a> An adhesive sheet was obtained in the same manner as in Example 1, except that component (C) was not added.

[0152] In Comparative Example 1a, the content of component (A) was 67.9% by mass, the content of component (B) was 31.9% by mass, and the content of component (C) was 0% by mass, relative to 100% by mass of the nonvolatile content of the adhesive composition. Table 1 below shows the results of the total light transmittance measured as described above.

[0153] <Comparative example 1b> An adhesive sheet was obtained in the same manner as in Example 1, except that component (B) was not blended and the blending amount of SEESORB703 as component (C) was changed to 2.2 parts by mass.

[0154] In Comparative Example 1b, the content of component (A) was 98.7% by mass, the content of component (B) was 0% by mass, and the content of component (C) was 1.0% by mass, relative to 100% by mass of the nonvolatile content of the adhesive composition. Table 1 below shows the results of the total light transmittance measured as described above.

[0155] [Table 1]

[0156] The results shown in Table 1 show that the adhesive layer of the adhesive sheet produced in Example 1 has improved light absorption ability in the short wavelength region while maintaining transparency.

[0157] <Example 2> An adhesive sheet was obtained in the same manner as in Example 1, except that 3.3 parts by mass of SEESORB 703 (manufactured by Shipro Chemical Co., Ltd.) was replaced with 330 parts by mass of a 99% by mass anon solution of HPH (manufactured by Sanwa Chemical Co., Ltd.) (non-volatile content: 3.3 parts by mass) as component (C).

[0158] In Example 2, the content of component (A) was 67.2 mass%, the content of component (B) was 31.6 mass%, and the content of component (C) was 1.0 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition. Table 2 below shows the results of the total light transmittance measured as described above.

[0159] <Comparative Example 2> An adhesive sheet was obtained in the same manner as in Example 2, except that component (B) was not added and the amount of component (C), a 99% by mass anhydrous HPH solution, was changed to 220 parts by mass (non-volatile content: 2.2 parts by mass).

[0160] In Comparative Example 2, the content of component (A) was 98.7% by mass, the content of component (B) was 0% by mass, and the content of component (C) was 1.0% by mass, relative to 100% by mass of the nonvolatile content of the adhesive composition. Table 2 below shows the results of the total light transmittance measured as described above.

[0161] [Table 2]

[0162] The results shown in Table 2 show that the adhesive layer of the adhesive sheet produced in Example 2 has improved light absorption ability in the short wavelength range while maintaining transparency.

[0163] Example 3 An adhesive sheet was obtained in the same manner as in Example 1, except that 22 parts by mass of a 15% by mass MEK solution of DAINSORB T-0 (manufactured by Yamato Chemical Industry Co., Ltd.) (non-volatile content: 3.3 parts by mass) was blended in place of 3.3 parts by mass of SEESORB 703 (manufactured by Shipro Chemical Industry Co., Ltd.) as component (C).

[0164] In Example 3, the content of component (A) was 67.2 mass%, the content of component (B) was 31.6 mass%, and the content of component (C) was 1.0 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition. Table 3 below shows the results of the total light transmittance measured as described above.

[0165] <Comparative Example 3> An adhesive sheet was obtained in the same manner as in Example 3, except that component (B) was not added and the amount of component (C), a 15% by mass MEK solution of DAINSORB T-0, was changed to 14.7 parts by mass (non-volatile content 2.2 parts by mass).

[0166] In Comparative Example 3, the content of component (A) was 98.7% by mass, the content of component (B) was 0% by mass, and the content of component (C) was 1.0% by mass, relative to 100% by mass of the nonvolatile content of the adhesive composition. Table 3 below shows the results of the total light transmittance measured as described above.

[0167] [Table 3]

[0168] The results shown in Table 3 show that the adhesive layer of the adhesive sheet produced in Example 3 has improved light absorption ability in the short wavelength region while maintaining transparency.

[0169] Example 4 An adhesive sheet was obtained in the same manner as in Example 1, except that 16.5 parts by mass of a 20% by mass toluene solution of SEESORB 107 (manufactured by Shipro Chemical Co., Ltd.) (3.3 parts by mass of non-volatile content) was blended instead of 3.3 parts by mass of SEESORB 703 (manufactured by Shipro Chemical Co., Ltd.) as component (C).

[0170] In Example 4, the content of component (A) was 67.2 mass%, the content of component (B) was 31.6 mass%, and the content of component (C) was 1.0 mass%, relative to 100 mass% of the nonvolatile content of the adhesive composition. Table 4 below shows the results of the total light transmittance measured as described above.

[0171] <Comparative Example 4> An adhesive sheet was obtained in the same manner as in Example 4, except that component (B) was not blended and component (C) was changed to 11.0 parts by mass of a 20% by mass toluene solution of SEESORB107 (nonvolatile content 2.2 parts by mass).

[0172] In Comparative Example 4, the content of component (A) was 98.7% by mass, the content of component (B) was 0% by mass, and the content of component (C) was 1.0% by mass, relative to 100% by mass of the nonvolatile content of the adhesive composition. Table 4 below shows the results of the total light transmittance measured as described above.

[0173] [Table 4]

[0174] The results shown in Table 4 show that the adhesive layer of the adhesive sheet produced in Example 4 has improved light absorption ability in the short wavelength region while maintaining transparency.

[0175] <Example 5> A mixture was obtained by mixing 60 parts by weight of liquid hydrogenated bisphenol A epoxy resin ("YX8000" manufactured by Mitsubishi Chemical Corporation) and 40 parts by weight of the semi-calcined hydrotalcite described above as component (B) using a triple roll mill. The resulting mixture was then blended with 1.5 parts by weight of a curing accelerator ("U-CAT3512T" manufactured by San-Apro Co., Ltd.), 57.2 parts by weight of a phenoxy resin solution ("YX7200B35" manufactured by Mitsubishi Chemical Corporation) (20 parts by weight of phenoxy resin), and 50 parts by weight of a solution of solid hydrogenated bisphenol A epoxy resin ("YX8040" manufactured by Mitsubishi Chemical Corporation) (solvent: MEK, non-volatile content: 40% by weight) (20 parts by weight of solid hydrogenated bisphenol A epoxy resin). The resulting mixture was further blended with 3 parts by weight of an ionic liquid curing agent (N-acetylglycine tetrabutylphosphonium salt) and 1.5 parts by weight of Seesorb 107 (Shipro Kasei Co., Ltd.) as component (C), and the resulting mixture was uniformly dispersed in a high-speed rotary mixer to obtain an adhesive composition varnish. The resulting varnish was uniformly applied to a polyethylene terephthalate (PET) film treated with a silicone-based release agent using a die coater, heated to 80°C for 5 minutes to dry, and then a release PET film was placed on the surface of the resin composition layer as a protective film to obtain an adhesive sheet.

[0176] In Example 5, the content of component (A) was 68.5% by mass, the content of component (B) was 27.4% by mass, and the content of component (C) was 1.0% by mass, relative to 100% by mass of the non-volatile content of the adhesive composition. Table 5 below shows the results of the total light transmittance measured as described above.

[0177] <Comparative Example 5> An adhesive sheet was obtained in the same manner as in Example 5, except that component (B) was not blended and the amount of component (C) SEESORB107 was changed to 1.1 parts by mass.

[0178] In Comparative Example 5, the content of component (A) was 94.7% by mass, the content of component (B) was 0% by mass, and the content of component (C) was 1.0% by mass, relative to 100% by mass of the nonvolatile content of the adhesive composition. Table 5 below shows the results of the total light transmittance measured as described above.

[0179] [Table 5]

[0180] The results shown in Table 5 show that the adhesive layer of the adhesive sheet produced in Example 5 has improved light absorption ability in the short wavelength region while maintaining transparency. [Industrial Applicability]

[0181] The adhesive composition of the present invention can form an adhesive layer that has the ability to absorb light in the wavelength range of 300 to 430 nm and has good transparency. Such an adhesive layer can prevent photodegradation of optical devices such as organic EL elements, and is particularly suitable for organic EL display devices.

[0182] This application is based on patent application No. 2018-219682 filed in Japan, the contents of which are incorporated in their entirety herein.

Claims

1. The following components (A) to (C): (A) an organic binder containing at least one selected from an olefin-based resin and an epoxy resin; (B) semi-calcined hydrotalcite, and (C) Benzotriazole-based compounds having a maximum absorption wavelength in the wavelength range of 300 to 430 nm 1. An adhesive composition comprising:

2. The following components (A) to (C): (A) an organic binder containing an epoxy resin; (B) semi-calcined hydrotalcite, and (C) A benzophenone-based compound having a maximum absorption wavelength in the wavelength range of 300 to 430 nm 1. An adhesive composition comprising:

3. 3. The adhesive composition according to claim 1, wherein the content of component (A) is 25 to 95% by mass relative to 100% by mass of the nonvolatile content of the adhesive composition.

4. 4. The adhesive composition according to claim 1, wherein the content of component (B) is 1 to 60% by mass relative to 100% by mass of the nonvolatile content of the adhesive composition.

5. 5. The adhesive composition according to claim 1, wherein the content of component (C) is 0.05 to 15% by mass relative to 100% by mass of the nonvolatile content of the adhesive composition.

6. The adhesive composition according to any one of claims 1 to 5, which is used to form an adhesive layer of an optical device.

7. The adhesive composition according to claim 6, wherein the optical device is an organic EL display device.

8. An adhesive sheet comprising a support and an adhesive layer formed on the support from the adhesive composition according to any one of claims 1 to 5.

9. The adhesive sheet according to claim 8, which is used to form an adhesive layer in an optical device.

10. The adhesive sheet according to claim 9, wherein the optical device is an organic EL display device.

11. An optical device having an adhesive layer formed from the adhesive composition according to any one of claims 1 to 5.

12. An organic EL display device having an adhesive layer formed from the adhesive composition according to any one of claims 1 to 5.

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