WO2018221571A1

WO2018221571A1 - Adhesive sheet, and sealed body

Info

Publication number: WO2018221571A1
Application number: PCT/JP2018/020731
Authority: WO
Inventors: 樹長谷川; 健太西嶋; 幹広樫尾
Original assignee: リンテック株式会社
Priority date: 2017-05-31
Filing date: 2018-05-30
Publication date: 2018-12-06
Also published as: TW201903106A; JPWO2018221571A1; TWI757498B; KR102469843B1; KR20200015450A; JP7138101B2

Abstract

The present invention pertains to an adhesive sheet having a thermosetting adhesive layer containing a polyfunctional epoxy compound, said adhesive sheet being characterized by having a specific shear characteristic and the content of the polyfunctional epoxy compound being 5 to 50 mass% relative to the total amount of the adhesive layer. According to the present invention, there is provided an adhesive sheet having adhesive layer with exceptional sealing properties, and a sealed body formed by sealing an object to be sealed using the sealing sheet.

Description

Adhesive sheet and sealing body

The present invention relates to an adhesive sheet having an adhesive layer excellent in sealability, and a sealed body obtained by sealing a seal with the adhesive sheet.

In recent years, organic EL elements have attracted attention as light emitting elements capable of high luminance light emission by low voltage direct current driving.
However, the organic EL element has a problem that light emission characteristics such as light emission luminance, light emission efficiency, light emission uniformity and the like are easily deteriorated with the passage of time.
As a cause of the problem of the deterioration of the light emission characteristic, it has been considered that oxygen, moisture and the like infiltrate into the inside of the organic EL element to deteriorate the electrode and the organic layer. For this reason, in order to solve this problem, using the adhesive sheet which is excellent in water blocking property as a sealing material has been proposed.

In addition, when manufacturing display devices such as liquid crystal displays (LCDs) and touch panels, adhesive sheets are used for the purpose of bonding optical members, but in recent years, in order to suppress mechanical deterioration of optical members, moisture blocking properties There is a need for a pressure sensitive adhesive sheet that is

As a pressure-sensitive adhesive sheet having such characteristics, Patent Document 1 proposes a pressure-sensitive adhesive sheet having a specific adhesive property and the like and containing a rubber-based resin as a main component.
In this document, the pressure-sensitive adhesive sheet is a pressure-sensitive adhesive sheet having a low water vapor permeability, which has sufficient adhesive strength even after wet heat, and suppresses yellowing when wet heat is passed, It is described that the pressure-sensitive adhesive sheet preferably contains a silane coupling agent in addition to the rubber-based resin because it is easy to express these characteristics.

JP, 2016-53157, A

As described in Patent Document 1, by using a pressure-sensitive adhesive composition containing a rubber-based resin as a main component, a pressure-sensitive adhesive sheet having excellent moisture blocking properties tends to be obtained.
However, according to the study of the present inventors, even with such a pressure-sensitive adhesive composition, the adhesion may be reduced after being placed under high humidity conditions, and it is used as a forming material of a sealing material. It turned out that there are things that can not be done.
Therefore, there has been a demand for a sealing material-forming material which has excellent sealing properties and maintains its performance even after being placed under high humidity conditions.

This invention is made in view of the said situation, provides the adhesive sheet which has an adhesive bond layer which is excellent in sealing property, and the sealing body formed by sealing a sealing thing by the said adhesive sheet. With the goal.

The present inventors diligently studied the adhesive layer in order to solve the above problems.
As a result, a thermosetting adhesive layer containing a specific proportion of a multifunctional epoxy compound, which has specific shear properties, is excellent in sealability and after being placed under high humidity conditions. Even then, they found that their performance was maintained, and came to complete the present invention.

Thus, according to the present invention, the following adhesive sheets (1) to (10), and (11) and (12) sealing bodies are provided.
(1) An adhesive sheet having a thermosetting adhesive layer containing a polyfunctional epoxy compound, wherein the content of the polyfunctional epoxy compound is 5 to 50% by mass in the entire adhesive layer, and the following conditions are satisfied: An adhesive sheet characterized by satisfying the following requirements [1] to [3] when the shear test (A) is carried out.
[Shear test (A)]
Prepare two rectangular alkali-free glasses with a short side of 10 mm, and on one of these sheets of alkali-free glass, a square adhesive layer with a side of 10 mm and a bonding area of 100 mm ² (10 mm × 10 mm) Then, they are laminated at a temperature of 60 ° C., a pressure of 0.2 MPa, and a laminating speed of 0.2 m / min. Next, another non-alkali glass is stacked on the side of the adhesive layer not in contact with the non-alkali glass so that the adhesion area is 100 mm ² (10 mm × 10 mm), and these are heated to 60 ° C. Lamination is performed under a pressure of 0.2 MPa and a lamination speed of 0.2 m / min to obtain a laminate. The laminate is then heated at 100 ° C. for 2 hours to cure the adhesive layer. Thereafter, the laminate is allowed to stand at 23 ° C. under a relative humidity of 50% for 24 hours to obtain a measurement sample. The shear load is measured at a shear rate of 0.1 mm / min using the obtained measurement sample.
[Requirements]
Requirement [1]: The maximum shear load (P ¹ _max ) is measured when the shear strain is less than 10,000%.
Requirement [2]: The value of the maximum shear load (P ¹ _max ) is 100 N or more.
Requirement [3]: The value of the shear load (P ¹ _10000% ) at a shear strain of 10,000% is 50% or more of the value of the maximum shear load (P ¹ _max ).
(2) The adhesive sheet according to (1), which satisfies the following requirement (4) when a shear test (B) is performed under the following conditions.
[Shear test (B)]
A measurement sample is produced in the same manner as the production method of the measurement sample in the shear test (A).
The measurement sample obtained is allowed to stand for 24 hours under conditions of a temperature of 60 ° C. and a relative humidity of 90% for 100 hours, and then under a condition of a temperature of 23 ° C. and a relative humidity of 50%. Measure the shear load at a shear rate of 0.1 mm / min.
[Requirements]
Requirement [4]: The value of the maximum shear load (P ² _max ) in the shear test (B) is 70% or more of the value of the maximum shear load (P ¹ _max ) in the shear test (1).
(3) The adhesive sheet according to (1) or (2), wherein the adhesive layer further contains a modified polyolefin resin.
(4) The adhesive sheet according to (3), wherein the content of the modified polyolefin resin is 40 to 90% by mass in the entire adhesive layer.
(5) The adhesive sheet according to any one of (1) to (4), wherein the adhesive layer further contains an imidazole-based curing catalyst.
(6) The adhesive sheet according to (5), wherein the content of the imidazole-based curing catalyst is 0.1 to 10 parts by mass with respect to 100 parts by mass of the polyfunctional epoxy compound contained in the adhesive layer.
(7) The adhesive sheet according to any one of (1) to (6), wherein the adhesive layer further contains a silane coupling agent.
(8) The adhesive sheet according to (7), wherein the content of the silane coupling agent is 0.01 to 2% by mass in the entire adhesive layer.
(9) The adhesive sheet according to any one of (1) to (8), wherein the thickness of the adhesive layer is 1 to 25 μm.
(10) The adhesive sheet according to any one of (1) to (9), further having a release film.
(11) A sealed body obtained by sealing an object to be sealed using the adhesive sheet according to any one of (1) to (10).
(12) The sealed body according to (11), wherein the object to be sealed is an organic EL element, an organic EL display element, a liquid crystal display element, or a solar cell element.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive sheet which has an adhesive layer which is excellent in sealing property, and the sealing body formed by sealing a to-be-sealed thing with the said adhesive sheet are provided.

Hereinafter, the present invention will be described in detail in terms of 1) an adhesive sheet and 2) a sealing body.

1) Adhesive sheet The adhesive sheet of the present invention is an adhesive sheet having a thermosetting adhesive layer containing a polyfunctional epoxy compound, and the content of the polyfunctional epoxy compound is 5 to 50 in the entire adhesive layer. It is a mass%, and when the above shear test (A) is performed, the above requirements [1] to [3] are satisfied.

[Adhesive layer]
The adhesive layer constituting the adhesive sheet of the present invention contains a polyfunctional epoxy compound.
The polyfunctional epoxy compound refers to a compound having two or more epoxy groups in the molecule.
By using an adhesive containing a polyfunctional epoxy compound, an adhesive layer satisfying the above requirements [1] to [3] can be efficiently formed.

As a polyfunctional epoxy compound, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, hydrogenated bisphenol S epoxy resin, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, water Added bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, pentaerythritol polyglycidyl ether, 1,6-hexane Allyl diglycidyl ether, hexahydrophthalic acid diglycidyl ester, neopentyl glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, 2,2-bis (3-glycidyl-4-glycidyloxyphenyl) propane, dimethylol tricyclode Candiglycidyl ether etc. are mentioned.
A polyfunctional epoxy compound can be used individually by 1 type or in combination of 2 or more types.
The molecular weight of the polyfunctional epoxy compound is preferably 50 to 10,000, more preferably 100 to 5,000.

The epoxy equivalent of the polyfunctional epoxy compound is preferably 100 g / eq or more and 500 g / eq or less, more preferably 150 g / eq or more and 300 g / eq or less. By using an adhesive having an epoxy equivalent of 100 g / eq or more and 500 g / eq or less of the polyfunctional epoxy compound, an adhesive sheet having an adhesive layer satisfying the above requirements [1] to [3] is more easily obtained.

The content of the polyfunctional epoxy compound is 5 to 50% by mass, preferably 10 to 40% by mass in the entire adhesive layer.
An adhesive layer containing too little content of a polyfunctional epoxy compound becomes difficult to satisfy above-mentioned requirements [1] and [2], and is inferior to adhesiveness. On the other hand, the adhesive layer having too much content of the polyfunctional epoxy compound is less likely to satisfy the above requirement [3], and is inferior in flexibility after curing.

The adhesive layer may contain a modified polyolefin resin as a component other than the polyfunctional epoxy compound.
By using an adhesive containing a modified polyolefin resin, an adhesive sheet having an adhesive layer satisfying the above requirements [1] to [3] can be more easily obtained.

The modified polyolefin resin is a polyolefin resin having a functional group introduced, which is obtained by subjecting a polyolefin resin as a precursor to a modification treatment using a modifier.

The polyolefin resin refers to a polymer containing a repeating unit derived from an olefin monomer. The polyolefin resin may be a polymer consisting only of repeating units derived from an olefin monomer, or a monomer derived from an olefin monomer and a monomer copolymerizable with the olefin monomer. It may be a polymer composed of the repeating units of

The olefin-based monomer is preferably an α-olefin having 2 to 8 carbon atoms, more preferably ethylene, propylene, 1-butene, isobutylene or 1-hexene, and still more preferably ethylene or propylene. These olefin monomers can be used alone or in combination of two or more.
As a monomer copolymerizable with an olefin type monomer, vinyl acetate, (meth) acrylic acid ester, styrene etc. are mentioned. Here, "(meth) acrylic acid" means acrylic acid or methacrylic acid (the same applies below).
The monomer copolymerizable with these olefin type monomers can be used individually by 1 type or in combination of 2 or more types.

As polyolefin resin, very low density polyethylene (VLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene, polypropylene (PP), ethylene-propylene co Examples thereof include a polymer, an olefin elastomer (TPO), an ethylene-vinyl acetate copolymer (EVA), an ethylene- (meth) acrylic acid copolymer, and an ethylene- (meth) acrylic acid ester copolymer.

The modifier used to modify the polyolefin resin is a compound having a functional group in the molecule.
As a functional group, a carboxyl group, a carboxylic acid anhydride group, a carboxylic acid ester group, a hydroxyl group, an epoxy group, an amide group, an ammonium group, a nitrile group, an amino group, an imide group, an isocyanate group, an acetyl group, a thiol group, an ether group , Thioether group, sulfone group, phosphonic group, nitro group, urethane group, halogen atom and the like. Among these, a carboxyl group, a carboxylic acid anhydride group, a carboxylic acid ester group, a hydroxyl group, an ammonium group, an amino group, an imide group and an isocyanate group are preferable, a carboxylic acid anhydride group and an alkoxysilyl group are more preferable, and a carboxylic acid anhydride Particular preference is given to
The compound having a functional group may have two or more types of functional groups in the molecule.

Examples of the modified polyolefin resin include an acid-modified polyolefin resin and a silane-modified polyolefin resin. From the viewpoint that the more excellent effect of the present invention can be obtained, the acid-modified polyolefin resin is preferable.

The acid-modified polyolefin resin refers to a resin obtained by graft-modifying a polyolefin resin with an acid. For example, a polyolefin resin is reacted with an unsaturated carboxylic acid or unsaturated carboxylic acid anhydride (hereinafter, these may be collectively referred to as "unsaturated carboxylic acid etc.") to give a carboxyl group or a carboxylic acid anhydride group. Are introduced (graft modified).

Examples of unsaturated carboxylic acids to be reacted with a polyolefin resin include unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, glutaronic acid, tetrahydrophthalic acid, aconitic acid, etc .; maleic anhydride, itaconic anhydride, anhydride And unsaturated carboxylic acid anhydrides such as glutaconic acid, citraconic acid anhydride, aconitic acid anhydride, norbornene dicarboxylic acid anhydride, and tetrahydrophthalic acid anhydride.
These can be used singly or in combination of two or more. Among these, maleic anhydride is preferable because an adhesive that is more excellent in adhesive strength can be easily obtained.

The amount of unsaturated carboxylic acid or the like to be reacted with the polyolefin resin is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, still more preferably 0.2 based on 100 parts by mass of the polyolefin resin. It is up to 1.0 parts by mass. The adhesive containing the acid-modified polyolefin resin thus obtained is more excellent in adhesive strength.

A commercial item can also be used as acid-modified polyolefin resin. Examples of commercially available products include Admar (registered trademark) (Mitsui Chemical Co., Ltd.), Unistoll (registered trademark) (Mitsui Chemical Co., Ltd.), BondyRam (Polyram), orevac (registered trademark) (ARKEMA), Modic (registered trademark) (manufactured by Mitsubishi Chemical Corporation) and the like.

The silane-modified polyolefin resin refers to a resin obtained by graft-modifying a polyolefin resin with an unsaturated silane compound. The silane modified polyolefin resin has a structure in which an unsaturated silane compound which is a side chain is graft copolymerized to a polyolefin resin which is a main chain. For example, silane modified polyethylene resin and silane modified ethylene-vinyl acetate copolymer can be mentioned. Among them, silane-modified polyethylene resins such as silane-modified low density polyethylene, silane-modified ultra-low density polyethylene, and silane-modified linear low density polyethylene are preferable.

As the unsaturated silane compound to be reacted with the above-mentioned polyolefin resin, a vinylsilane compound is preferable. For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltripentyloxy Silane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, vinyltricarboxysilane and the like can be mentioned. These can be used alone or in combination of two or more.
The conditions in the case of graft-polymerizing an unsaturated silane compound to the polyolefin resin which is a principal chain may adopt a well-known graft polymerization method.

The amount of the unsaturated silane compound to be reacted with the polyolefin resin is preferably 0.1 to 10 parts by mass, preferably 0.3 to 7 parts by mass, with respect to 100 parts by mass of the polyolefin resin. More preferably, it is 5 to 5 parts by mass. When the amount of the unsaturated silane compound to be reacted is in the above range, the adhesive containing the silane-modified polyolefin-based resin to be obtained is more excellent in adhesive strength.

A commercial item can also be used as silane modification polyolefin resin. As a commercial item, for example, LINCTRON (registered trademark) (manufactured by Mitsubishi Chemical Corporation) and the like can be mentioned. Among them, the low density polyethylene-based linkleon, the linear low density polyethylene-based lindleon, the ultra low density polyethylene-based lincolon, and the ethylene-vinyl acetate copolymer-based lincolone can be preferably used.

The modified polyolefin resin can be used singly or in combination of two or more.

The number average molecular weight (Mn) of the modified polyolefin resin is preferably 10,000 to 2,000,000, and more preferably 20,000 to 1,500,000.
The number average molecular weight (Mn) of the modified polyolefin resin can be determined as a standard polystyrene conversion value by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

When the adhesive layer contains a modified polyolefin resin, the content of the modified polyolefin resin is preferably 40 to 90% by mass, more preferably 50 to 80% by mass, based on the entire adhesive layer.
When the content of the modified polyolefin resin is in the above range, the adhesive layer can more easily satisfy the requirements [1] to [3].

The adhesive layer may contain an imidazole-based curing catalyst as a component other than the polyfunctional epoxy compound.
By using an adhesive containing an imidazole curing catalyst, an adhesive sheet having an adhesive layer satisfying the above requirements [1] to [3] can be more easily obtained.

As an imidazole series curing catalyst, 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl -4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole and the like. Among these, 2-ethyl-4-methylimidazole is preferable.
These imidazole curing catalysts can be used alone or in combination of two or more.

When the adhesive layer contains an imidazole-based curing catalyst, the content of the imidazole-based curing catalyst is preferably 0.1 to 10 parts by mass, more preferably 0.2 based on 100 parts by mass of the polyfunctional epoxy compound. 5 parts by mass. When the content of the imidazole-based curing catalyst is in the above range, the adhesive layer can more easily satisfy the requirements [1] to [3].

The adhesive layer may contain a silane coupling agent as a component other than the polyfunctional epoxy compound.
By using an adhesive containing a silane coupling agent, an adhesive sheet having an adhesive layer satisfying the above requirements [1] to [3] can be more easily obtained.

A well-known silane coupling agent can be used as a silane coupling agent. Among them, organic silicon compounds having at least one alkoxysilyl group in the molecule are preferable.
As a silane coupling agent, polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane and the like; 3-glycidoxypropyltrimethoxysilane, 2- (3,4 Silicon compounds having an epoxy structure such as -epoxycyclohexyl) ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) Amino group-containing silicon compounds such as -3-aminopropylmethyldimethoxysilane; 3-chloropropyltrimethoxysilane; 3-isocyanatopropyltriethoxysilane; and the like.
These silane coupling agents can be used singly or in combination of two or more.

When the adhesive layer contains a silane coupling agent, the content of the silane coupling agent is preferably 0.01 to 2% by mass, more preferably 0.05 to 1% by mass, based on the entire adhesive layer. .
When the content of the silane coupling agent is in the above range, the adhesive layer can more easily satisfy the requirements [1] to [3].

The adhesive layer may contain other components as long as the effects of the present invention are not impaired.
Other components include additives such as ultraviolet light absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, pigments, extenders, and softeners.
These can be used singly or in combination of two or more.
When the adhesive layer contains these additives, the content can be appropriately determined according to the purpose.

The thickness of the adhesive layer is preferably 1 to 25 μm, more preferably 3 to 20 μm.
The adhesive layer has a thermosetting property. That is, by heating the adhesive layer, at least the epoxy group of the polyfunctional epoxy compound is reacted to cure the adhesive layer.
The conditions at which the adhesive layer is thermally cured are not particularly limited.
The heating temperature is usually 80 to 200 ° C., preferably 90 to 150 ° C.
The heating time is usually 30 minutes to 12 hours, preferably 1 to 6 hours.
The water vapor transmission rate of the adhesive layer after curing is usually 0.1 to 200 g · m ⁻² · day ⁻¹ , preferably 1 to 150 g · m ⁻² · day ⁻¹ .
The water vapor permeability can be measured using known gas permeability measuring devices.

The adhesive layer satisfies the following requirements [1] to [3] when the shear test (A) is performed under the following conditions.
[Shear test (A)]
Prepare two rectangular alkali-free glasses with a short side of 10 mm, and on one of these sheets of alkali-free glass, a square adhesive layer with a side of 10 mm and a bonding area of 100 mm ² (10 mm × 10 mm) Then, they are laminated at a temperature of 60 ° C., a pressure of 0.2 MPa, and a laminating speed of 0.2 m / min. Next, another non-alkali glass is stacked on the side of the adhesive layer not in contact with the non-alkali glass so that the adhesion area is 100 mm ² (10 mm × 10 mm), and these are heated to 60 ° C. Lamination is performed under a pressure of 0.2 MPa and a lamination speed of 0.2 m / min to obtain a laminate. The laminate is then heated at 100 ° C. for 2 hours to cure the adhesive layer. Thereafter, the laminate is allowed to stand at 23 ° C. under a relative humidity of 50% for 24 hours to obtain a measurement sample. The shear load is measured under the conditions of a shear rate of 0.1 mm / min and an atmosphere at a room temperature of 23 ° C. and a relative humidity of 50% using the obtained measurement sample.

Requirement [1]: The maximum shear load (P ¹ _max ) is measured when the shear strain is less than 10,000%.
Requirement [2]: The value of the maximum shear load (P ¹ _max ) is 100 N or more.
Requirement [3]: The value of the shear load (P ¹ _10000% ) at a shear strain of 10,000% is 50% or more of the value of the maximum shear load (P ¹ _max ).

The shear strain means the amount of displacement in the horizontal direction with respect to the thickness of the adhesive layer, and is calculated by the following equation.

For example, when the thickness of the adhesive layer is 10 μm, the shear strain of 10,000% means that the upper surface of the adhesive layer is horizontally offset by 1000 μm with respect to the lower surface.

Shear test (A) is a test to evaluate the shear properties of the adhesive under normal conditions.
The adhesive layer of the adhesive sheet of the present invention satisfies the requirement [1] when the shear test (A) is performed. That is, the adhesive layer of the adhesive sheet of the present invention is one that is measured when the maximum shear load (P ¹ _max ) is less than 10,000% shear strain.
The adhesive layer satisfying the requirement [1] is preferable from the viewpoint of sealability.
By including 5 to 50% by mass of the polyfunctional epoxy resin in the adhesive layer, an adhesive layer satisfying the requirement [1] can be easily obtained.

The adhesive layer of the adhesive sheet of the present invention satisfies the requirement [2] when the shear test (A) is performed. That is, the adhesive layer of the adhesive sheet of the present invention has a maximum shear load (P ¹ _max ) value of 100 N or more.
The adhesive layer satisfying the requirement [2] is preferable from the viewpoint of sealability.
By including 5 to 50% by mass of the polyfunctional epoxy resin in the adhesive layer, an adhesive layer satisfying the requirement [2] can be easily obtained.

The adhesive layer of the adhesive sheet of the present invention satisfies the requirement [3] when the shear test (A) is performed. That is, in the adhesive layer of the adhesive sheet of the present invention, the shear load (P ¹ _10000% ) at a shear strain of 10,000% is 50% or more of the value of the maximum shear load (P ¹ _max ) It is.
The adhesive layer satisfying the requirement [3] is preferable from the viewpoint of flexibility when sealing the object to be sealed.
By including 5 to 50% by mass of the multifunctional epoxy resin in the adhesive layer, an adhesive layer satisfying the requirement [3] can be easily obtained.
Furthermore, by containing the modified polyolefin resin in the adhesive layer, an adhesive layer satisfying the requirement [3] can be more easily obtained.

The adhesive layer of the adhesive sheet of the present invention preferably satisfies the following requirement [4] when the shear test (B) is performed under the following conditions.
[Shear test (B)]
A measurement sample is produced in the same manner as the production method of the measurement sample in the shear test (A).
The measurement sample obtained is allowed to stand for 24 hours under conditions of a temperature of 60 ° C. and a relative humidity of 90% for 100 hours, and then under a condition of a temperature of 23 ° C. and a relative humidity of 50%. The shear load is measured under conditions of a shear rate of 0.1 mm / min and an atmosphere at a room temperature of 23 ° C. and a relative humidity of 50%.
Requirement [4]: The value of the maximum shear load (P ² _max ) in the shear test (B) is 70% or more of the value of the maximum shear load (P ¹ _max ) in the shear test (A).

The shear test (B) is a test to evaluate the shear properties of the adhesive layer after being placed under high humidity conditions.
The adhesive layer satisfying the requirement [4] is preferable in that it has excellent durability after sealing the object to be sealed.
By including a silane coupling agent in the adhesive layer, an adhesive layer satisfying the requirement [4] can be easily obtained.

[Peeling film]
The adhesive sheet of the present invention may have a release film.
The release film functions as a support in the manufacturing process of the adhesive sheet, and also functions as a protective sheet of the adhesive layer until the adhesive sheet is used.
When using the adhesive sheet of the present invention, the release film is usually peeled off.

As a peeling film, a conventionally well-known thing can be utilized. For example, what has a peeling layer in which the peeling process was carried out by the peeling agent on the base material for peeling films is mentioned.
As substrates for release films, paper substrates such as glassine paper, coated paper, high-quality paper, etc .; laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper substrates; polyethylene terephthalate resin, polybutylene terephthalate resin, Plastic films, such as polyethylene naphthalate resin, a polypropylene resin, polyethylene resin ;; etc. are mentioned.
Examples of the release agent include silicone resins, olefin resins, isoprene resins, rubber elastomers such as butadiene resins, long chain alkyl resins, alkyd resins, fluorine resins and the like.

When the adhesive sheet of the present invention has a peelable film, the number of peelable films may be one or two, but generally, two on each side of the adhesive layer. The release film of At this time, the two peelable films may be identical or different, but the two peelable films preferably have different peel strengths. When the peeling force of the two peeling films is different, a problem is less likely to occur when using the adhesive sheet. That is, the process of peeling a peeling film initially can be performed more efficiently by making the peeling force of two peeling films different.

[Adhesive sheet]
The method for producing the adhesive sheet is not particularly limited. For example, an adhesive sheet can be manufactured using a cast method.
When the adhesive sheet is produced by a casting method, for example, a coating liquid containing the components of the adhesive layer and a solvent is prepared, and the obtained coating liquid is applied to the release treated surface of the release film, and thus obtained. By drying the coated film, an adhesive layer with a release film can be produced, and then, another release film can be laminated on the adhesive layer to obtain an adhesive sheet.

Examples of solvents used for preparation of the coating liquid include aromatic hydrocarbon solvents such as benzene and toluene; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; n-pentane And aliphatic hydrocarbon solvents such as n-hexane and n-heptane; alicyclic hydrocarbon solvents such as cyclopentane, cyclohexane and methylcyclohexane; and the like.
These solvents can be used alone or in combination of two or more.
The content of the solvent can be appropriately determined in consideration of coating properties and the like.

As a method of applying a coating liquid, a spin coat method, a spray coat method, a bar coat method, a knife coat method, a roll coat method, a blade coat method, a die coat method, a gravure coat method etc. are mentioned, for example.
Drying conditions for drying the coating include, for example, a drying temperature of 80 to 150 ° C., and a drying time of 30 seconds to 5 minutes.

As described above, the adhesive layer of the adhesive sheet of the present invention has the above-mentioned shear properties and is excellent in sealability. Therefore, by forming the sealing material using the adhesive sheet of the present invention, it is possible to achieve long life of the organic EL element and the like.

3) Sealed body The sealed body of the present invention is obtained by sealing an object to be sealed using the adhesive sheet of the present invention.
The sealing body of the present invention includes, for example, a substrate, an element (object to be sealed) formed on the substrate, and a sealing material for sealing the element. What is a thing derived from the adhesive bond layer of the adhesive sheet of this invention (hardened material of an adhesive bond layer) is mentioned for a sealing material.

The substrate is not particularly limited, and various substrate materials can be used. In particular, it is preferable to use a substrate material having a high visible light transmittance. In addition, a material having a high blocking performance to block moisture and gas from the outside of the element and having excellent solvent resistance and weather resistance is preferable. Specifically, transparent inorganic materials such as quartz and glass; polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polyethylene, polypropylene, polyphenylene sulfide, polyvinylidene fluoride, acetyl cellulose, brominated phenoxy, aramids, polyimides, Transparent plastics, such as polystyrenes, polyarylates, polysulfones, polyolefins, and the gas barrier film mentioned above;
The thickness of the substrate is not particularly limited, and can be appropriately selected in consideration of the light transmittance and the performance of blocking the inside and outside of the device.

As an object to be sealed, an organic EL element, an organic EL display element, a liquid crystal display element, a solar cell element and the like can be mentioned.

The manufacturing method of the sealing body of this invention is not specifically limited. For example, after the adhesive layer of the adhesive sheet of the present invention is stacked on an object to be sealed, the adhesive layer of the adhesive sheet is adhered to the object by heating.
Then, the adhesive layer is cured to produce the sealed body of the present invention.

The bonding conditions for bonding the adhesive layer of the adhesive sheet and the object to be sealed are not particularly limited. The adhesion temperature is, for example, 23 to 100 ° C., preferably 40 to 80 ° C. This adhesion process may be performed while applying pressure.
As the curing conditions for curing the adhesive layer, the conditions described above can be used.

The sealed body of the present invention is obtained by sealing an object to be sealed with the adhesive sheet of the present invention.
Therefore, in the sealed body of the present invention, the performance of the sealed object is maintained for a long time.

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples.
Parts and% in each example are based on mass unless otherwise noted.

Example 1
Acid-modified polyolefin resin (acid-modified α-olefin polymer, manufactured by Mitsui Chemicals, trade name: Unistol H-200, number average molecular weight: 47,000) 76.6 parts, multifunctional epoxy compound (1) (water Added bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd., trade name: YX8034, 23.0 parts of epoxy equivalent weight, imidazole-based curing catalyst (manufactured by Shikoku Kasei Co., Ltd., trade name: Cuazole 2E4MZ, 2-ethyl-4-) 0.3 part of methylimidazole and 0.1 part of silane coupling agent (1) (8-glycidoxyoctyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM4803) are dissolved in methyl ethyl ketone and solid Adhesive composition 1 having a concentration of 18% was prepared.
This adhesive composition 1 is coated on the release-treated surface of a release film (Lintech Co., Ltd., trade name: SP-PET 382150), and the obtained coating film is dried at 100 ° C. for 2 minutes, and has a thickness of 10 μm An agent layer was formed, and the release-treated surface of another release film (Lintech Co., Ltd., trade name: SP-PET 381031) was bonded thereon to obtain an adhesive sheet 1.

Example 2
In Example 1, in place of the polyfunctional epoxy compound (1), a polyfunctional epoxy compound (2) (hydrogenated bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX 8000, epoxy equivalent 205 g / eq) is used An adhesive composition 2 was prepared in the same manner as in Example 1 except for the above, and an adhesive sheet 2 was obtained using this.

[Example 3]
In Example 1, in place of the polyfunctional epoxy compound (1), a polyfunctional epoxy compound (3) (hydrogenated bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX8040, epoxy equivalent: 1100 g / eq) is used An adhesive composition 3 was prepared in the same manner as in Example 1 except for the above, and an adhesive sheet 3 was obtained using this.

Example 4
In Example 1, in place of the silane coupling agent (1), a silane coupling agent (2) (3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM 403) is used. An adhesive composition 4 was prepared in the same manner as in Example 1 except for the above, and an adhesive sheet 4 was obtained using this.

[Example 5]
In Example 1, in place of the polyfunctional epoxy compound (1), polyfunctional epoxy compound (4) (hydrogenated bisphenol A diglycidyl ether, manufactured by Kyoeisha Chemical Co., Ltd., trade name: Epolite 4000, epoxy equivalent weight 215 to 245 g / eq The adhesive composition 5 was prepared in the same manner as in Example 1 except that the above was used, to obtain an adhesive sheet 5.

[Example 6]
In Example 5, in place of the silane coupling agent (1), a silane coupling agent (2) (3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM 403) was used. An adhesive composition 6 was prepared in the same manner as in Example 5 except for the above, and an adhesive sheet 6 was obtained using this.

Comparative Example 1
An adhesive composition 7 was prepared in the same manner as in Example 1 except that the multifunctional epoxy compound (1) was not used in Example 1, and an adhesive sheet 7 was obtained using this.

Comparative Example 2
77 parts of n-butyl acrylate, 20 parts of methyl acrylate, 3 parts of acrylic acid, 200 parts of ethyl acetate, 2,2'-azo, in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device and nitrogen introducing pipe 0.16 parts of bisisobutyronitrile was charged, and the copolymerization was carried out at 70 ° C. in a nitrogen gas atmosphere to obtain an acrylic polymer (1) having a weight average molecular weight (Mw) of 800,000.
97.4 parts of acrylic polymer (1), 2.3 parts of trimethylolpropane adduct of tolylene diisocyanate, 0.3 parts of aluminum trisacetylacetonate, mixed solvent of toluene / ethyl acetate [mixing ratio (volume ratio) ): 3/2] to prepare an adhesive composition 8 having a solid concentration of 21%. An adhesive sheet 8 was obtained in the same manner as in Example 1, except that the adhesive composition 8 was used.

Comparative Example 3
60 parts of 2-ethylhexyl acrylate, 20 parts of methyl methacrylate, 20 parts of hydroxyethyl acrylate, 200 parts of ethyl acetate, 2,2'-, in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device and nitrogen introduction pipe 0.16 parts of azobisisobutyronitrile was charged, and a copolymerization reaction was carried out at 70 ° C. in a nitrogen gas atmosphere to obtain an acrylic polymer (2) having a weight average molecular weight (Mw) of 700,000.
99.5 parts of acrylic polymer (2), 0.2 part of trimethylolpropane adduct of tolylene diisocyanate, 0.3 part of 3-glycidoxypropyltrimethoxysilane in mixed solvent of ethyl acetate / methyl ethyl ketone [mixing ratio (Volume ratio): 4/1] was dissolved to prepare an adhesive composition 9 having a solid content concentration of 35%. An adhesive sheet 9 was obtained in the same manner as in Example 1, except that the adhesive composition 9 was used.

Comparative Example 4
Polyisoprene rubber (having a carboxylic acid functional group) per 100 parts of a copolymer of isobutylene and isoprene (manufactured by Nippon Butyl Co., Exxon Butyl 268, number average molecular weight 260,000, content of isoprene 1.7 mol%) ( Kuraray LIR 410, number average molecular weight 30,000, average number of carboxyl groups per molecule: 10, 5 parts, aliphatic petroleum resin (Nippon Zeon Co., Quinton A100, softening point 100 ° C.) 20 parts, crosslinking agent One part of an epoxy compound (TC-5, manufactured by Mitsubishi Chemical Corporation) was dissolved in toluene to obtain an adhesive composition 10 having a solid content concentration of 25%. An adhesive sheet 10 was obtained in the same manner as Example 1, except that the adhesive composition 10 was used.

The following tests were conducted on the adhesive sheets 1 to 10 obtained in Examples 1 to 6 and Comparative Examples 1 to 4.
[Shear test (A)]
The adhesive sheet obtained in the example or the comparative example was processed into a square having a side of 10 mm.
Two pieces of rectangular alkali-free glass having a short side of 10 mm were prepared. The peeling film of the above-mentioned square adhesive sheet is peeled off, and the remaining adhesive sheet is not present so that the exposed adhesive layer faces the non-alkali glass and the adhesion area is 100 mm ² (10 mm × 10 mm). They were placed on alkali glass and laminated using a pressure roller at a temperature of 60 ° C., a pressure of 0.2 MPa, and a laminating speed of 0.2 m / min. Then, another release film is peeled off, another alkali-free glass is overlaid on the exposed adhesive layer so that the adhesion area is 100 mm ² (10 mm × 10 mm), and these are applied using a pressure roller. Were laminated under conditions of a temperature of 60 ° C., a pressure of 0.2 MPa and a laminating speed of 0.2 m / min to obtain a laminate.
The laminate was then heated at 100 ° C. for 2 hours to cure the adhesive layer. Thereafter, the laminate was allowed to stand at 23 ° C. under a relative humidity of 50% for 24 hours to obtain a measurement sample.
The shear load was measured at a shear rate of 0.1 mm / min using the obtained measurement sample.

[Shear test (B)]
A measurement sample was produced in the same manner as the production method of the measurement sample in the shear test (A).
The measurement sample obtained is allowed to stand for 24 hours under conditions of a temperature of 60 ° C. and a relative humidity of 90% for 100 hours, and then under a condition of a temperature of 23 ° C. and a relative humidity of 50%. The shear load was measured at a shear rate of 0.1 mm / min.

[Evaluation test of organic EL element]
An organic EL element having a glass substrate on which an indium tin oxide (ITO) film (thickness: 100 nm, sheet resistance: 50 Ω / □ (ohm / square)) was formed as an anode was manufactured by the following method.
First, 50 nm of N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) -benzidine) (manufactured by Luminescence Technology) on the ITO film of the glass substrate, Tris (8-) A light emitting layer was formed by sequentially depositing hydroxy-quinolinate) aluminum (manufactured by Luminescence Technology) at a rate of 50 nm, 0.1 to 0.2 nm / min.
Lithium fluoride (LiF) (manufactured by High Purity Chemical Laboratory Co., Ltd.) 4 nm at a rate of 0.1 nm / min as an electron injecting material on the obtained light emitting layer, then aluminum (Al) (high purity chemical research laboratory ) Was deposited at a rate of 0.1 nm / min to form a cathode, whereby an organic EL device was obtained.
The degree of vacuum at the time of deposition was all 1 × 10 ⁻⁴ Pa or less.

One release film of the adhesive sheet obtained in Example or Comparative Example was peeled off, the exposed adhesive layer was stacked on a metal foil film, and these were adhered at 60 ° C. using a heat laminator. Next, another release film was peeled off, and the exposed adhesive layer was overlapped so as to cover the organic EL element formed on the glass substrate, and these were adhered at 60 ° C. using a heat laminator. Then, the adhesive layer was cured by heating at 100 ° C. for 2 hours to obtain a bottom emission type electronic device in which the organic EL element was sealed.
This electronic device is allowed to stand for 250 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90%, and then the organic EL element is activated to observe the presence or absence of dark spots (non-light emitting places). did.
◎: dark spot is less than 40% of light emitting area Δ: dark spot is 40% to less than 50% of light emitting area x: dark spot is 50% or more of light emitting area The evaluation results are shown in Table 1.

Table 1 shows the following.
The adhesive layer of the adhesive sheet obtained in Examples 1 to 6 is excellent in sealability, and the occurrence of dark spots can be suppressed by sealing the organic EL element using these.
On the other hand, the adhesive layer of the adhesive sheet obtained in Comparative Examples 1 to 4 does not have predetermined shear characteristics, and these are inferior in sealability.

Claims

An adhesive sheet having a thermosetting adhesive layer containing a polyfunctional epoxy compound,
The content of the polyfunctional epoxy compound is 5 to 50% by mass in the entire adhesive layer,
An adhesive sheet characterized by satisfying the following requirements (1) to (3) when performing a shear test (A) under the following conditions.
[Shear test (A)]
Prepare two rectangular alkali-free glasses with a short side of 10 mm, and on one of these sheets of alkali-free glass, a square adhesive layer with a side of 10 mm and a bonding area of 100 mm 2 (10 mm × 10 mm) Then, they are laminated at a temperature of 60 ° C., a pressure of 0.2 MPa, and a laminating speed of 0.2 m / min. Next, another non-alkali glass is stacked on the side of the adhesive layer not in contact with the non-alkali glass so that the adhesion area is 100 mm 2 (10 mm × 10 mm), and these are heated to 60 ° C. Lamination is performed under a pressure of 0.2 MPa and a lamination speed of 0.2 m / min to obtain a laminate. The laminate is then heated at 100 ° C. for 2 hours to cure the adhesive layer. Thereafter, the laminate is allowed to stand at 23 ° C. under a relative humidity of 50% for 24 hours to obtain a measurement sample. The shear load is measured at a shear rate of 0.1 mm / min using the obtained measurement sample.
[Requirements]
Requirement [1]: The maximum shear load (P 1 max ) is measured when the shear strain is less than 10,000%.
Requirement [2]: The value of the maximum shear load (P 1 max ) is 100 N or more.
Requirement [3]: The value of the shear load (P 1 10000% ) at a shear strain of 10,000% is 50% or more of the value of the maximum shear load (P 1 max ).
The adhesive sheet according to claim 1, wherein when the shear test (B) is performed under the following conditions, the following requirement (4) is satisfied.
[Shear test (B)]
A measurement sample is produced in the same manner as the production method of the measurement sample in the shear test (A).
The measurement sample obtained is allowed to stand for 24 hours under conditions of a temperature of 60 ° C. and a relative humidity of 90% for 100 hours, and then under a condition of a temperature of 23 ° C. and a relative humidity of 50%. Measure the shear load at a shear rate of 0.1 mm / min.
[Requirements]
Requirement [4]: The value of the maximum shear load (P 2 max ) in the shear test (2) is 70% or more of the value of the maximum shear load (P 1 max ) in the shear test (A).
The adhesive sheet according to claim 1, wherein the adhesive layer further contains a modified polyolefin resin.
The adhesive sheet according to claim 3, wherein the content of the modified polyolefin resin is 40 to 90% by mass in the entire adhesive layer.
The adhesive sheet according to any one of claims 1 to 4, wherein the adhesive layer further contains an imidazole-based curing catalyst.
The adhesive sheet according to claim 5, wherein the content of the imidazole-based curing catalyst is 0.1 to 10 parts by mass with respect to 100 parts by mass of the polyfunctional epoxy compound contained in the adhesive layer.
The adhesive sheet according to any one of claims 1 to 6, wherein the adhesive layer further contains a silane coupling agent.
The adhesive sheet according to claim 7, wherein the content of the silane coupling agent is 0.01 to 2% by mass in the entire adhesive layer.
The adhesive sheet according to any one of claims 1 to 8, wherein the thickness of the adhesive layer is 1 to 25 μm.
The adhesive sheet according to any one of claims 1 to 9, further comprising a release film.
A sealed body obtained by sealing an object to be sealed with the adhesive sheet according to any one of claims 1 to 10.
The sealed body according to claim 11, wherein the object to be sealed is an organic EL element, an organic EL display element, a liquid crystal display element, or a solar cell element.