JP7071279B2 - Adhesive composition, encapsulation sheet, and encapsulant - Google Patents

Description

In the present invention, an adhesive composition having excellent moisture barrier properties and adhesive strength, a sealing sheet having an adhesive layer formed by using this adhesive composition, and an object to be sealed are sealed with the sealing sheet. With respect to the sealed body.

In recent years, organic EL elements have been attracting attention as light emitting elements capable of high-luminance light emission by low-voltage direct current drive.
However, the organic EL element has a problem that the light emission characteristics such as the light emission brightness, the light emission efficiency, and the light emission uniformity tend to deteriorate with the passage of time.
It is conceivable that oxygen, water, or the like infiltrate the inside of the organic EL element to deteriorate the electrode and the organic layer as a cause of the problem that the light emission characteristic is deteriorated.
Then, as a coping method, some methods using a sealing material have been proposed. For example, Patent Document 1 describes a sheet-like encapsulation containing an olefin polymer having a heat of fusion and a weight average molecular weight within a specific range and a hydrocarbon-based synthetic oil having a kinematic viscosity at 40 ° C. within a specific range. The material is listed.

Japanese Unexamined Patent Publication No. 2015-137333

The sheet-shaped encapsulant described in Patent Document 1 has a feature that it can be peeled off as needed. However, this sheet-shaped encapsulant tends to be inferior in adhesive strength.
It is often used for an object to be sealed such as an organic EL element under harsh conditions such as outdoors and inside a vehicle. Therefore, there has been a demand for a sealing sheet having excellent adhesive strength in addition to excellent moisture blocking property, and an adhesive composition suitably used as a raw material for such a sealing sheet.

The present invention has been made in view of the above circumstances, and is an adhesive composition having excellent moisture-blocking properties and adhesive strength, a sealing sheet having an adhesive layer formed by using this adhesive composition, and a coated sheet. It is an object of the present invention to provide a sealed body in which a sealed material is sealed with the sealing sheet.

As a result of diligent studies to solve the above problems, the present inventors have made an adhesive formed by using an adhesive composition containing a modified polyolefin resin, a polyfunctional epoxy compound, a curing accelerator, and a silane coupling agent. The layer has been found to be excellent in moisture-blocking property and adhesive strength, and has completed the present invention.

Thus, according to the present invention, the following adhesive compositions [1] to [7], sealing sheets [8] to [11], and sealing bodies [12] and [13] are provided. ..
[1] The following (A) component, (B) component, (C) component, and (D) component (A) component: modified polyolefin resin (B) component: polyfunctional epoxy compound (C) component: curing acceleration Agent (D) component: An adhesive composition containing a silane coupling agent, and when a 180 ° peeling test was performed on a test piece obtained by using this adhesive composition, the following formula (1) The adhesive composition, wherein the x value calculated in 1 is 1.3 or less.

(In the formula, a represents the adhesive strength obtained by performing a 180 ° peeling test under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, and b represents a condition of the test piece having a temperature of 60 ° C. and a relative humidity of 90%. Adhesive strength obtained by performing a 180 ° peeling test under the conditions of a temperature of 23 ° C. and a relative humidity of 50% after allowing the material to stand under the conditions of a temperature of 23 ° C. and a relative humidity of 50% for 24 hours. In these 180 ° peeling test test pieces, a sealing sheet composed of an adhesive layer having a thickness of 20 μm and a polyethylene terephthalate film having a thickness of 50 μm obtained by using an adhesive composition is formed on the adhesive layer. One side is placed on a glass plate and laminated under the conditions of a temperature of 60 ° C., a pressure of 0.2 MPa and a speed of 0.2 m / min (min), and then the obtained crimped body is heated at 100 ° C. for 2 hours. , A laminated body having a width of 25 mm obtained by curing the adhesive layer.)

[2] The adhesive composition according to [1], wherein the component (A) is an acid-modified polyolefin-based resin.
[3] The adhesive composition according to [1] or [2], wherein the content of the component (B) is 10 to 50 parts by mass with respect to 100 parts by mass of the component (A).
[4] The adhesive composition according to any one of [1] to [3], wherein the component (C) is an imidazole-based curing accelerator.
[5] The adhesive composition according to any one of [1] to [4], wherein the content of the component (C) is 0.1 to 10 parts by mass with respect to 100 parts by mass of the component (A). thing.
[6] The adhesive composition according to any one of [1] to [5], wherein the component (D) is a compound represented by the following formula (2).

(R ¹ represents an alkylene group having 3 or more carbon atoms, R ² represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, R ³ represents an alkyl group having 1 to 4 carbon atoms, and Z represents a reactive group. Represents a group containing a group, where n is 0 or 1).
[7] The adhesive composition according to any one of [1] to [6], wherein the content of the component (D) is 0.05 to 5 parts by mass with respect to 100 parts by mass of the component (A). thing.
[8] A sealing sheet composed of two release films and an adhesive layer sandwiched between the release films, wherein the adhesive layer is described in any one of [1] to [7]. A sealing sheet formed using an adhesive composition.
[9] A sealing sheet composed of a release film, a gas barrier film, and an adhesive layer sandwiched between the release film and the gas barrier film.
A sealing sheet in which the adhesive layer is formed by using the adhesive composition according to any one of [1] to [7].
[10] The sealing sheet according to [9], wherein the gas barrier film is a metal foil, a resin film, or a thin film glass.
[11] The sealing sheet according to any one of [8] to [10], wherein the thickness of the adhesive layer is 1 to 50 μm.
[12] A sealed body in which the material to be sealed is sealed using the sealing sheet according to any one of [8] to [11].
[13] The sealed body according to [12], 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.

According to the present invention, an adhesive composition having excellent moisture blocking properties and adhesive strength, a sealing sheet having an adhesive layer formed by using this adhesive composition, and an object to be sealed are the sealing sheets. A sealed body is provided.

Hereinafter, the present invention will be described in detail by dividing it into 1) an adhesive composition, 2) a sealing sheet, and 3) a sealing body.

1) Adhesive composition The adhesive composition of the present invention has the following components (A), (B), (C), and (D) component (A): modified polyolefin resin (B) component. : Polyfunctional epoxy compound (C) component: Curing accelerator (D) component: An adhesive composition containing a silane coupling agent, and the X value calculated by the above formula (1) is 1.3 or less. It is characterized by being.

Component (A): Modified Polyolefin Resin The adhesive composition of the present invention contains a modified polyolefin resin as the component (A).
The adhesive composition of the present invention contains a modified polyolefin-based resin, so that the adhesive composition has excellent adhesive strength. Further, by using an adhesive composition containing a modified polyolefin resin, an adhesive layer having a thickness described later can be efficiently formed.

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

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

As the olefin-based monomer, α-olefin having 2 to 8 carbon atoms is preferable, ethylene, propylene, 1-butene, isobutylene, 1-pentene, or 1-hexene is more preferable, and ethylene or propylene is further preferable.
Examples of the monomer copolymerizable with the olefin-based monomer include vinyl acetate, (meth) acrylic acid, (meth) acrylic acid ester, and styrene. Here, (meth) acrylic acid means acrylic acid or methacrylic acid.

Examples of the polyolefin resin include ultra-low density polyethylene (VLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP), and ethylene. Examples thereof include a propylene copolymer, an olefin-based 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 for the modification treatment of the polyolefin resin is a compound having a functional group in the molecule, that is, a group capable of contributing to a crosslinking reaction described later.
Functional groups include carboxyl group, carboxylic acid anhydride group, carboxylic acid ester group, hydroxyl group, epoxy group, amide group, ammonium group, nitrile group, amino group, imide group, isocyanate group, acetyl group, thiol group and ether group. , Thioether group, sulfone group, phosphonic acid group, nitro group, urethane group, alkoxysilyl group, silanol 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, an isocyanate group and an alkoxysilyl group are preferable, and a carboxylic acid anhydride group and an alkoxysilyl group are more preferable. , Carous acid anhydride groups are particularly preferred.
The compound having a functional group may have two or more kinds of functional groups in the molecule.

Examples of the modified polyolefin-based resin include acid-modified polyolefin-based resins and silane-modified polyolefin-based resins, and acid-modified polyolefin-based resins are preferable from the viewpoint of obtaining more excellent effects of the present invention.

The acid-modified polyolefin-based resin refers to a polyolefin resin graft-modified with an acid. For example, a polyolefin resin is reacted with an unsaturated carboxylic acid to introduce a carboxyl group (graft modification). In addition, in this specification, unsaturated carboxylic acid includes the concept of carboxylic acid anhydride.

The acid-modified polyolefin resin can be obtained, for example, by a method of graft-polymerizing an unsaturated carboxylic acid on a polyolefin resin in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound.

As unsaturated carboxylic acids to be reacted with the polyolefin resin, maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, Examples thereof include aconitic anhydride, norbornene dicarboxylic acid anhydride, tetrahydrophthalic acid anhydride and the like.
These can be used alone or in combination of two or more. Among these, maleic anhydride is preferable because it is easy to obtain an adhesive composition having better adhesive strength.

The amount of the unsaturated carboxylic acid 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, and further preferably 0.2 to 0.2 parts by mass with respect to 100 parts by mass of the polyolefin resin. 1 part by mass. When the amount of the unsaturated carboxylic acid to be reacted is in the above range, the obtained adhesive composition containing the acid-modified polyolefin resin becomes more excellent in adhesive strength.

As the acid-modified polyolefin resin, a commercially available product can also be used. Examples of commercially available products include Admer (registered trademark) (Mitsui Chemicals), Unistor (registered trademark) (Mitsui Chemicals), BondyRam (Polyram), orevac (registered trademark) (ARCEMA), and the like. Modic (registered trademark) (manufactured by Mitsubishi Chemical Corporation) and the like can be mentioned.

The silane-modified polyolefin-based resin is a polyolefin resin graft-modified with an unsaturated silane compound. The silane-modified polyolefin-based resin has a structure in which an unsaturated silane compound is graft-copolymerized with the polyolefin resin.

As the conditions for graft-polymerizing the unsaturated silane compound on the polyolefin resin, a known conventional method of graft polymerization may be adopted. For example, a method in which a polyolefin resin, an unsaturated silane compound and a radical generator are melt-mixed at a high temperature and graft-polymerized can be mentioned.

The unsaturated silane compound to be reacted with the polyolefin resin is preferably a vinylsilane compound, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltripentyroxy. Examples thereof include silane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, vinyltricarboxysilane and the like. These can be used alone or in combination of two or more.

The amount of the unsaturated silane compound to be reacted with the polyolefin resin is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass with respect to 100 parts by mass of the polyolefin resin. It is more preferably 0.5 to 5 parts by mass. When the amount of the unsaturated silane compound to be reacted is in the above range, the obtained adhesive composition containing the silane-modified polyolefin resin becomes more excellent in adhesive strength.

Examples of the silane-modified polyolefin resin include a silane-modified polyethylene resin and a silane-modified ethylene-vinyl acetate copolymer. Of these, silane-modified polyethylene resins such as silane-modified low-density polyethylene, silane-modified linear low-density polyethylene, and silane-modified ultra-low-density polyethylene are preferable.

Commercially available products can also be used as the silane-modified polyolefin-based resin. Examples of commercially available products include Linkron (registered trademark) (manufactured by Mitsubishi Chemical Corporation), among which low-density polyethylene-based Linkron, linear low-density polyethylene-based Linkron, and ultra-low-density polyethylene-based products. Wrinklon and Wrinklon of the ethylene-vinyl acetate copolymer system can be preferably used.

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

The mass average molecular weight (Mw) of the modified polyolefin resin is 10,000 to 2,000,000, preferably 20,000 to 1,500,000.
The mass average molecular weight (Mn) of the modified polyolefin resin can be determined as a standard polystyrene-equivalent value by performing gel permeation chromatography using tetrahydrofuran as a solvent.

Component (B): Polyfunctional Epoxy Compound The adhesive composition of the present invention contains a polyfunctional epoxy compound as the component (B).
Since the polyfunctional epoxy compound reacts with the component (A) to form a crosslinked structure, the cured product of the adhesive composition of the present invention is excellent in water vapor blocking property.

The polyfunctional epoxy compound means a compound having at least two or more epoxy groups in the molecule.
Examples of the epoxy compound having two or more epoxy groups include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, and brominated bisphenol S. Diglycidyl ether, novolac type epoxy resin (for example, phenol / novolak type epoxy resin, cresol / novolak type epoxy resin, brominated phenol / novolak type epoxy resin), hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, Hydrogenated bisphenol S diglycidyl ether, pentaerythritol polyglycidyl ether, 1,6-hexanediol diglycidyl ether, hexahydrophthalic acid diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, 2,2- Examples thereof include bis (3-glycidyl-4-glycidyloxyphenyl) propane and dimethyloltricyclodecanediglycidyl ether.
These polyfunctional epoxy compounds can be used alone or in combination of two or more.

The molecular weight of the polyfunctional epoxy compound is usually 100 to 10,000, preferably 200 to 5,000.
The epoxy equivalent of the polyfunctional epoxy compound is preferably 100 to 2000 g / eq, more preferably 150 to 1500 g / eq.

The content of the polyfunctional epoxy compound in the adhesive composition is preferably 10 to 50 parts by mass, more preferably 15 to 40 parts by mass with respect to 100 parts by mass of the component (A). A cured product of an adhesive composition in which the content of the polyfunctional epoxy compound is within this range is superior in water vapor blocking property.

Component (C): Curing Accelerator The adhesive composition of the present invention contains a curing accelerator as the component (C).
By using an adhesive composition containing a curing accelerator, it becomes easy to obtain a cured product having excellent adhesiveness even at a high temperature (for example, 60 ° C.).
The curing accelerator is not particularly limited as long as it promotes a crosslinking reaction involving a polyfunctional epoxy compound or the like.

Examples of the curing accelerator include an imidazole-based curing accelerator, a tertiary amine-based curing accelerator, a phosphine-based curing accelerator, a quaternary ammonium salt-based curing accelerator, a quaternary phosphonium salt-based curing accelerator, and a metal. Examples include compound-based curing accelerators.
Among these, an imidazole-based curing accelerator is preferable from the viewpoint of obtaining a cured product having more excellent adhesive strength.

Examples of the imidazole-based curing accelerator include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2-. Examples thereof include phenyl-4-methyl-5-hydroxymethylimidazole and 2-phenyl-4,5-dihydroxymethylimidazole.
Examples of the tertiary amine-based curing accelerator include benzyldimethylamine, tris (dimethylaminomethyl) phenol, cyclohexyldimethylamine, triethylamine and 1,8-diazabicyclo [5.4.0] undecene-7 (DBU). Can be mentioned.
Examples of the phosphine-based curing accelerator include triphenylphosphine and triphenyl phosphite.

Examples of the quaternary ammonium salt-based curing accelerator include tetraethylammonium bromide, tetrabutylammonium bromide, tetraalkylammonium carboxylate, and benzyltriphenylammonium carboxylate.
Examples of the quaternary phosphonium salt-based curing accelerator include tetraphenylphosphonium bromide and tetra-n-butylphosphonium bromide.
Examples of the metal compound-based curing accelerator include boron trifluoride, triphenylborate, zinc chloride, tin chloride, aluminum alkoxide, titanium alkoxide, zirconium alkoxide, aluminum tris (acetylacetone), and aluminum tris (ethylacetacetate). , Magnesium bis (acetylacetonate), magnesium bis (ethylacetoneacetate), zirconium tetraacetylacetonate, aluminum bisethylacetate acetate, monoacetylacetonate and the like.

These curing accelerators can be used alone or in combination of two or more.
The content of the curing accelerator in the adhesive composition is preferably 0.1 to 10 parts by mass, and more preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the component (A).
A cured product of an adhesive composition having a content of a curing accelerator within this range has excellent adhesiveness even at a high temperature (for example, 60 ° C.).

Component (D): Silane Coupling Agent The adhesive composition of the present invention contains a silane coupling agent as the component (D).
By using an adhesive composition containing a silane coupling agent, a cured product having better adhesiveness at room temperature (usually 20 to 30 ° C.) and in a high temperature and high humidity environment (for example, 60 ° C., relative humidity 90%). Is easy to obtain.

The silane coupling agent is generally an organic silicon compound having a functional group that reacts with an organic material in the molecule and a functional group (halogen atom, alkoxy group, etc.) that reacts with an inorganic material at the same time. The silane coupling agent is not particularly limited, and conventionally known silane coupling agents can be used. Among them, the silane compound represented by the following formula (2) is preferable from the viewpoint of obtaining a resin composition having more excellent adhesive strength.

In the formula (2), R ¹ represents an alkylene group having 3 or more carbon atoms, R ² represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, and R ³ represents an alkyl group having 1 to 4 carbon atoms. .. Z represents a group containing a reactive group, and n is 0 or 1.

The alkylene group represented by ^R1 has 3 or more carbon atoms, preferably 3 to 20 and more preferably 4 to 15.
When the number of carbon atoms of the alkylene group is 3 or more, the crosslinking reaction is more likely to occur.
Examples of the alkylene group represented by R ¹ include a trimethylene group, a propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group and the like.

The monovalent hydrocarbon group represented by ^R2 has 1 to 10 carbon atoms, preferably 1 to 6 and more preferably 1 to 4.
The monovalent hydrocarbon group represented by ^R2 includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a t-butyl group and an n-pentyl group. Alkyl group such as group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group; vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 3- Alkenyl groups such as butenyl group, 4-pentenyl group and 5-hexenyl group; alkynyl groups such as ethynyl group, propargyl group and butynyl group; aryl groups such as phenyl group, 1-naphthyl group and 2-naphthyl group; and the like. Be done.

The alkyl group represented by R ³ has 1 to 4 carbon atoms, preferably 1 to 3 and more preferably 1 or 2.
Examples of the alkyl group represented by R ³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group and a t-butyl group.

Examples of the reactive group contained in Z include an amino group, a hydroxyl group, a thiol group, a vinyl group, an acryloyl group, a methacryloyl group, an epoxy group and the like, and an epoxy group is preferable.
Examples of Z containing an epoxy group include an epoxy group, a glycidyl group, a 3,4-epoxycyclohexyl group and the like.

Examples of the silane coupling agent represented by the formula (2) include 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxy. Propyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 8-glycidoxyoctyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) Examples thereof include ethyltriethoxysilane.

The silane coupling agent can be used alone or in combination of two or more.
The content of the silane coupling agent in the adhesive composition is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the component (A).
A cured product of an adhesive composition having a silane coupling agent content within this range has excellent adhesiveness even at high temperatures (for example, 60 ° C.).

The adhesive composition of the present invention may contain components other than the above-mentioned components (A) to (D).
Examples of the components other than the components (A) to (D) include solvents and various additives.
As the solvent, 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, n-hexane and n- An aliphatic hydrocarbon solvent such as heptane; an alicyclic hydrocarbon solvent such as cyclopentane, cyclohexane, and methylcyclohexane; and the like can be mentioned.
These solvents can be used alone or in combination of two or more.
The amount of the solvent used can be appropriately determined in consideration of coatability and the like.

Examples of the additive include a tackifier, an ultraviolet absorber, an antistatic agent, a light stabilizer, an antioxidant, a resin stabilizer, a filler, a pigment, a bulking agent, a softening agent and the like.
These can be used alone or in combination of two or more.
When the adhesive composition of the present invention contains these additives, the content thereof can be appropriately determined according to the purpose.

The adhesive composition of the present invention can be prepared by appropriately mixing and stirring predetermined components according to a conventional method.

The adhesive composition of the present invention has excellent moisture blocking properties. The water vapor permeability of the layer (adhesive layer after the curing treatment) obtained by curing the adhesive layer formed from the adhesive composition of the present invention is usually 0.1 to 200 g · m ^-2 · day. ^-1 , preferably 1 to 150 g · m − ² · day ^-1 .
The water vapor permeability of the adhesive layer can be measured by the dry / wet sensor method (Lyssy method) described in JIS K 7129: 2008.

The adhesive composition of the present invention has excellent adhesive strength. In particular, it has a feature that the adhesive strength is unlikely to decrease even when it is placed under high temperature and high humidity conditions after adhesion.
For example, when a 180 ° peeling test is performed on a test piece obtained by using the adhesive composition of the present invention, the x value calculated by the following formula (1) is 1.3 or less, more preferably. It is 1.2 or less, and particularly preferably less than 1.0. The lower limit of the x value is preferably 0.6 or more, more preferably 0.8 or more.

In formula (1), a represents the adhesive strength obtained by performing a 180 ° peeling test under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, and b represents a test piece having a temperature of 60 ° C. and a relative humidity of 90%. It was obtained by allowing it to stand for 100 hours under the conditions of 1) and then for 24 hours under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, and then performing a 180 ° peeling test under the conditions of a temperature of 23 ° C. and a relative humidity of 50%. Represents adhesive strength.

The value of a is usually 1 to 100 N / 25 mm, preferably 10 to 50 N / 25 mm.
The value of b is usually 1 to 100 N / 25 mm, preferably 10 to 50 N / 25 mm.
The relationship between the value of a and the value of b is preferably b> a.

For these 180 ° peeling test test pieces, a sealing sheet made of an adhesive layer having a thickness of 20 μm and a polyethylene terephthalate film having a thickness of 50 μm obtained by using an adhesive composition was used as an adhesive layer of the sealing sheet. Lay the other side on the glass plate (so that the side not adjacent to the polyethylene terephthalate film faces the glass plate) at a temperature of 60 ° C., a pressure of 0.2 MPa, and a speed of 0.2 m / min. It is a laminated body having a width of 25 mm obtained by laminating and then heating the obtained crimped body at 100 ° C. for 2 hours to cure the adhesive layer.
An adhesive composition having an X of 1.3 or less has a strong interface strength between the adhesive composition and the adherend at the time of adhesion, and can prevent the infiltration of water.
The material of the glass plate used for producing the test piece is not particularly limited, but non-alkali glass is usually used. Further, the thickness thereof is not particularly limited, but for example, a thickness of 0.7 mm can be used.

An adhesive composition having such physical characteristics can be easily obtained by balancing the functional group in the component (A), the epoxy group in the component (B), and the reactive group in the component (C).
The functional group in the component (A) is a reactive group capable of reacting with the epoxy resin, and a carboxylic acid anhydride group is particularly preferable.
Further, the epoxy group in the component (B) reacts with the reactive group of the component (A) and crosslinks to form a strong structure. Therefore, a sufficient amount of epoxy group is required for the reactive group of the component (A). Specifically, it is preferable to adjust the amount of the component (B) so that the amount of the epoxy group is 10 to 100 equivalents with respect to the reactive group of the component (A).
The component (C) is incorporated into the crosslinked structure of the component (A) and the component (B) to strongly adhere the adhesive composition to the adherend. Therefore, the reactive group of the component (C) is preferably a glycidyl group having the same reactivity as the component (B).

Since the adhesive composition of the present invention is excellent in moisture blocking property and adhesive strength, the adhesive composition of the present invention is suitably used when forming a sealing material.

2) Encapsulation sheet The encapsulation sheet of the present invention is the following encapsulation sheet (α) or encapsulation sheet (β).
Sealing sheet (α): A sealing sheet composed of two release films and an adhesive layer sandwiched between these release films, wherein the adhesive layer uses the adhesive composition of the present invention. Sealing sheet (β): A sealing sheet composed of a release film, a gas barrier film, and an adhesive layer sandwiched between the release film and the gas barrier film. The adhesive layer is formed by using the adhesive composition of the present invention. It should be noted that these sealing sheets represent the state before use. When using the sealing sheet of the present invention, the release film is usually peeled off.

[Sealing sheet (α)]
The release film constituting the sealing sheet (α) functions as a support in the manufacturing process of the sealing sheet (α) and protects the adhesive layer until the sealing sheet (α) is used. Functions as a sheet.

As the release film, a conventionally known one can be used. For example, a base material for a release film having a release layer that has been peeled with a release agent can be mentioned.
As the base material for the release film, paper base materials such as glassin paper, coated paper, and high-quality paper; laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials; polyethylene terephthalate resin, polybutylene terephthalate resin, etc. Plastic films such as polyethylene naphthalate resin, polypropylene resin, and polyethylene resin; and the like.
Examples of the release agent include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins, and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, and fluorine-based resins.

The two release films in the sealing sheet (α) may be the same or different from each other, but it is preferable that the two release films have different release forces. Since the peeling forces of the two release films are different, problems are less likely to occur when the sealing sheet is used. For example, it is possible to more efficiently perform the step of peeling the release film by using two release films having different release forces and first peeling the release film having a weak release force.

The thickness of the adhesive layer of the sealing sheet (α) is usually 1 to 50 μm, preferably 5 to 30 μm. An adhesive layer having a thickness within the above range is suitably used as a sealing material.

Since the adhesive layer of the sealing sheet (α) is formed by using the adhesive composition of the present invention, it has thermosetting property.
When the sealing sheet (α) is used, for example, the sealing body can be obtained as follows. First, the release film is peeled off from the sealing sheet (α) to expose the adhesive layer, and then the exposed adhesive layer is crimped so as to cover the adherend in an uncured state, and then obtained. A sealed body can be obtained by heating the laminated laminate to a predetermined temperature and thermosetting the adhesive layer.
When another layer is further laminated on the obtained sealing body, the remaining release sheet of the sealing sheet (α) is peeled off, and another layer is formed on the exposed adhesive layer. It may be laminated. This operation may be performed with the adhesive layer uncured, or may be performed after the adhesive layer has been cured.

The conditions for crimping the adhesive layer to the adherend are not particularly limited.
The temperature is usually 23 to 100 ° C, preferably 40 to 80 ° C.
The pressure is usually 0.1 to 0.5 MPa, preferably 0.2 to 0.3 MPa.

The conditions for thermosetting the adhesive layer 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.

When the 180 ° peeling test is performed on the adhesive layer after the curing treatment at 23 ° C., the adhesive strength is usually 1 to 100 N / 25 mm, preferably 10 to 50 N / 25 mm. This 180 ° peel test can be performed according to the method described in Examples.
In addition, the adhesive layer after the curing treatment has excellent moisture blocking properties. The water vapor permeability of the adhesive layer after the curing treatment is usually 0.1 to 200 g · m ^-2 · day ^-1 , preferably 1 to 150 g · m ^-2 · day ^-1 .
The water vapor permeability of the adhesive layer can be measured by the dry / wet sensor method (Lyssy method) described in JIS K 7129: 2008.

The method for producing the sealing sheet (α) is not particularly limited. For example, a sealing sheet (α) can be produced by using a casting method.
When the sealing sheet (α) is produced by the casting method, the adhesive composition of the present invention is applied to the peeled surface of the release film by a known method, and the obtained coating film is dried. The sealing sheet (α) can be obtained by producing an adhesive layer with a release film and then superimposing another release film on the adhesive layer.

Examples of the method for applying the adhesive composition include a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method.
Examples of the drying conditions for drying the coating film include 30 seconds to 5 minutes at 80 to 150 ° C.

[Sealing sheet (β)]
The sealing sheet (β) is a sealing sheet composed of a release film, a gas barrier film, and an adhesive layer sandwiched between the release film and the gas barrier film, and the adhesive layer is the present invention. It is characterized in that it is formed by using the adhesive composition of.
It should be noted that these sealing sheets represent a state before use, and when the sealing sheet of the present invention is used, the release film is usually peeled off.

The two release films in the sealing sheet (β) may be the same or different from each other, but it is preferable that the two release films have different release forces. Since the peeling forces of the two release films are different, problems are less likely to occur when the sealing sheet is used. For example, if the release film having a weak peeling force is first peeled off, the step of peeling off the release film can be performed more efficiently.

The gas barrier film is not particularly limited as long as it is a film having a moisture barrier property.
The gas barrier film preferably has a water vapor permeability of 0.1 g / m ² / day or less in an environment of a temperature of 40 ° C. and a relative humidity of 90% (hereinafter, abbreviated as “90% RH”), and is 0. It is more preferably 0.05 g / m ² / day or less, and further preferably 0.005 g / m ² / day or less.
When the water vapor transmittance of the gas barrier film in an environment of 40 ° C. and 90% RH is 0.1 g / m ² / day or less, oxygen or oxygen can be contained in the organic EL element or the like formed on the transparent substrate. It is possible to effectively suppress the deterioration of the electrode and the organic layer due to the infiltration of water and the like.
The transmittance of the gas barrier film such as water vapor can be measured using a known gas permeability measuring device.

Examples of the gas barrier film include metal foil, resin film, thin film glass and the like. Among these, a resin film is preferable, and a gas barrier film having a resin film (base material) and a gas barrier layer is more preferable.

Examples of the metal of the metal foil include metal materials such as copper, nickel and aluminum; alloy materials such as stainless steel or aluminum alloys; and the like.

The composition and composition of the thin film glass are not particularly limited, but non-alkali borosilicate glass is preferable in that more stable flexibility can be obtained.
As the thin film glass, the thin film glass may be used as a single unit, or a metal foil such as an aluminum foil or a resin film laminated or laminated on the thin film glass may be used.
Further, as the thin film glass, one having flexibility having a thickness of about 10 to 200 μm is preferable.

In a gas barrier film having a base material and a gas barrier layer, the resin components constituting the base material include polyimide, polyamide, polyamideimide, polyphenylene ether, polyether ketone, polyether ether ketone, polyolefin, polyester, polycarbonate, polysulfone, and the like. Examples thereof include polyether sulfone, polyphenylene sulfide, polyarylate, acrylic resin, cycloolefin polymer, aromatic polymer, polyurethane polymer and the like.
The thickness of the base material is not particularly limited, but is preferably 0.5 to 500 μm, more preferably 1 to 200 μm, and even more preferably 5 to 100 μm from the viewpoint of ease of handling.

The material of the gas barrier layer is not particularly limited as long as it can impart desired gas barrier properties. Examples of the gas barrier layer include an inorganic film and a layer obtained by subjecting a layer containing a polymer compound to a modification treatment. Among these, the gas barrier layer is preferably a gas barrier layer made of an inorganic film or a gas barrier layer obtained by injecting ions into a layer containing a polymer compound because a layer having a thin thickness and excellent gas barrier properties can be efficiently formed. ..

The inorganic film is not particularly limited, and examples thereof include an inorganic thin-film film.
Examples of the inorganic vapor deposition film include a vapor deposition film of an inorganic compound or a metal.
Inorganic oxides such as silicon oxide, aluminum oxide, magnesium oxide, zinc oxide, indium oxide, and tin oxide; inorganic nitrides such as silicon nitride, aluminum nitride, and titanium nitride; inorganic carbides; Examples thereof include inorganic sulfides; inorganic oxynitrides such as silicon oxide nitride; inorganic oxidative carbides; inorganic nitriding carbides; and inorganic oxynitride carbides.
Examples of the raw material of the metal vapor deposition film include aluminum, magnesium, zinc, tin and the like.

Examples of the method for forming the inorganic film include a vacuum vapor deposition method, an EB vapor deposition method, a sputtering method, an ion plating method, a laminating method, and a plasma vapor deposition method (CVD method).
The thickness of the inorganic film is appropriately selected depending on the type and composition of the inorganic material, but is usually 1 to 500, preferably 2 to 300 nm.

In the gas barrier layer obtained by ionizing a layer containing a polymer compound (hereinafter, may be referred to as a "polymer layer"), the polymer compound used is a silicon-containing polymer such as polyorganosiloxane or polysilazane-based compound. Compounds, polyimides, polyamides, polyamideimides, polyphenylene ethers, polyether ketones, polyether ether ketones, polyolefins, polyesters, polycarbonates, polysulfones, polyethersulfones, polyphenylene sulfides, polyarylates, acrylic resins, cycloolefin polymers, aromatics Examples include system polymers. These polymer compounds can be used alone or in combination of two or more.
Among these, silicon-containing polymer compounds are preferable, and polysilazane-based compounds are more preferable, from the viewpoint of being able to form a gas barrier layer having excellent gas barrier properties.

A polysilazane-based compound is a polymer compound having a repeating unit containing a —Si—N— bond (silazane bond) in the molecule. Specifically, equation (3)

A compound having a repeating unit represented by is preferable. The number average molecular weight of the polysilazane compound used is not particularly limited, but is preferably 100 to 50,000.

In the above equation (3), r represents an arbitrary natural number.
Rx, Ry and Rz are independently hydrogen atom, alkyl group having unsubstituted or substituent, cycloalkyl group having unsubstituted or substituent, alkenyl group having unsubstituted or substituent, unsubstituted or substituted. Represents a non-hydrolytable group such as an aryl group having a group or an alkylsilyl group. Among these, as Rx, Ry, and Rz, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group is preferable, and a hydrogen atom is particularly preferable. The polysilazane compound having a repeating unit represented by the formula (3) is any of inorganic polysilazane in which Rx, Ry and Rz are all hydrogen atoms, and organic polysilazane in which at least one of Rx, Ry and Rz is not a hydrogen atom. May be.

The polysilazane-based compound can be used alone or in combination of two or more. In the present invention, a modified polysilazane can also be used as the polysilazane compound. Further, in the present invention, as the polysilazane-based compound, a commercially available product commercially available as a glass coating material or the like can be used as it is.

In addition to the above-mentioned polymer compound, the polymer layer may contain other components as long as the object of the present invention is not impaired. Examples of other components include curing agents, other polymers, antiaging agents, light stabilizers, flame retardants and the like.
The content of the polymer compound in the polymer layer is preferably 50% by mass or more, more preferably 70% by mass or more, because a gas barrier layer having more excellent gas barrier properties can be obtained.

The thickness of the polymer layer is not particularly limited, but is preferably in the range of 50 to 300 nm, more preferably 50 to 200 nm.
In the present invention, even if the thickness of the polymer layer is on the nano-order, a sealing sheet having sufficient gas barrier properties can be obtained.

As a method for forming a polymer layer, for example, a known layer-forming solution containing at least one polymer compound, optionally other components, a solvent and the like, such as a spin coater, a knife coater, and a gravure coater. Examples thereof include a method of applying using an apparatus and appropriately drying and forming the obtained coating film.

Examples of the polymer layer modification treatment include ion implantation treatment, plasma treatment, ultraviolet irradiation treatment, heat treatment and the like.
The ion implantation treatment is a method of modifying the polymer layer by injecting ions into the polymer layer, as will be described later.
Plasma treatment is a method of modifying a polymer layer by exposing the polymer layer to plasma. For example, plasma treatment can be performed according to the method described in Japanese Patent Application Laid-Open No. 2012-106421.
The ultraviolet irradiation treatment is a method of irradiating a polymer layer with ultraviolet rays to modify the polymer layer. For example, the ultraviolet modification treatment can be performed according to the method described in Japanese Patent Application Laid-Open No. 2013-226757.
Among these, the ion implantation treatment is preferable because it can efficiently modify the inside of the polymer layer without roughening the surface and form a gas barrier layer having more excellent gas barrier properties.

The ions injected into the polymer layer include rare gas ions such as argon, helium, neon, krypton, and xenon; ions such as fluorocarbon, hydrogen, nitrogen, oxygen, carbon dioxide, chlorine, fluorine, and sulfur;
Alkane-based gas ions such as methane and ethane; Alken-based gas ions such as ethylene and propylene; Alkene-based gas ions such as pentadiene and butadiene; Alkin-based gas ions such as acetylene; Benzene, toluene, etc. Aromatic hydrocarbon gas ions; cycloalkane gas ions such as cyclopropane; cycloalkene gas ions such as cyclopentene; metal ions; organic silicon compound ions; and the like.
These ions can be used alone or in combination of two or more.
Among these, rare gas ions such as argon, helium, neon, krypton, and xenon are preferable because ions can be injected more easily and a gas barrier layer having particularly excellent gas barrier properties can be obtained.

The method of injecting ions is not particularly limited. For example, a method of irradiating ions (ion beams) accelerated by an electric field, a method of injecting ions in plasma (ions of plasma-producing gas), and the like can be mentioned. Since a gas barrier layer can be easily obtained, the latter plasma. The method of injecting ions is preferable. In the plasma ion injection method, for example, plasma is generated in an atmosphere containing a plasma generating gas, and a negative high voltage pulse is applied to the layer into which the ions are injected to generate ions (cations) in the plasma. Can be injected into the surface of the layer to be injected with.

The gas barrier film may have a primer layer provided between the base material and the gas barrier layer. By providing the primer layer, it may be possible to improve the adhesion between the base material and the gas barrier layer.

The material constituting the primer layer is not particularly limited, and known materials can be used. For example, a silicon-containing compound; a photopolymerizable composition comprising a photopolymerizable monomer and / or a photopolymerizable prepolymer, and a polymerization initiator that generates radicals in light at least in the visible light region; polyester-based. Resins, polyurethane resins (particularly polyacrylic polyols, polyester polyols, polyether polyols, etc. and isocyanate compounds, two-component curable resins), acrylic resins, polycarbonate resins, vinyl chloride / vinyl acetate copolymers, polyvinyl butyral-based Resins such as resins and nitrocellulose resins; alkyl titanates; polyethyleneimine; and the like can be mentioned. These materials can be used alone or in combination of two or more.
As the primer layer, the methods shown above can be used as the method for applying the solution for forming the primer layer and the method for drying and heating the obtained coating film, respectively, as the method for forming the polymer layer. When forming a primer layer, the thickness of the primer layer is usually 10 to 1000 nm.

The method for producing the sealing sheet (β) is not particularly limited. For example, in the method for producing the sealing sheet (α) described above, the sealing sheet (β) can be produced by replacing one of the release films with a gas barrier film.
Further, after the sealing sheet (α) is manufactured, the sealing sheet (β) is manufactured by peeling off one of the release films and attaching the exposed adhesive layer and the gas barrier film. You can also. In this case, when the sealing sheet (α) has two release films having different release forces, it is preferable to release the release film having the smaller release force from the viewpoint of handleability.

The adhesive layer of the sealing sheet of the present invention is excellent in adhesive strength and moisture blocking property. Therefore, by sealing the organic EL element using the sealing sheet of the present invention, its deterioration can be efficiently suppressed.

3) Encapsulant In the encapsulation body of the present invention, the object to be sealed is sealed by using the encapsulation sheet of the present invention.
"Sealed using the sealing sheet of the present invention" means that the release film constituting the sealing sheet of the present invention is removed to expose the adhesive layer, and the adhesive layer is used as an object to be sealed. It means to cover the object to be sealed by making it adhere to.
The encapsulant of the present invention includes, for example, a transparent substrate, an element (object to be sealed) formed on the transparent substrate, and a sealing material for encapsulating the element. , The sealing material is sealed by the adhesive layer of the sealing sheet (α) or (β) of the present invention.

Specific examples of the layer structure of the sealed body of the present invention include, but are not limited to, the following. In the following, the description will be made in a manner in which the release film is peeled off and removed.
(I) Transparent substrate / Element (encapsulated object) formed on the transparent substrate / Adhesive layer (ii) Transparent substrate / Element (encapsulated object) formed on the transparent substrate / Adhesive layer / Gas barrier layer (iii) transparent substrate / element formed on the transparent substrate (object to be sealed) / adhesive layer / gas barrier layer / base film (iv) transparent substrate / element formed on the transparent substrate (Material to be sealed) / Adhesive layer / Gas barrier layer / Primer layer / Base film

The transparent 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. Further, a material having 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, acetylcellulose, brominated phenoxy, aramids, polyimides, etc. Examples thereof include transparent plastics such as polystyrenes, polyarylates, polysulfones and polyolefins, and the above-mentioned gas barrier film.
The thickness of the transparent 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 element.

Examples of the object to be sealed include an organic EL element, an organic EL display element, a liquid crystal display element, a solar cell element and the like.

The method for producing the sealed body of the present invention is not particularly limited. For example, the adhesive layer of the sealing sheet of the present invention is layered on the object to be sealed, and then heated to bond the adhesive layer of the sealing sheet and the object to be sealed.
Then, by curing this adhesive layer, the sealed body of the present invention can be produced.

The conditions described above can be used as the curing conditions when the adhesive layer of the sealing sheet and the object to be sealed are brought into close contact with each other and when the adhesive layer is cured.

In the sealed body of the present invention, the object to be sealed is sealed with the sealing sheet of the present invention.
Therefore, in the sealed body of the present invention, the performance of the object to be sealed is maintained for a long period of time.

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

The compounds used in the examples or comparative examples are as follows.
Acid-modified polyolefin resin (1): modified α-olefin polymer, mass average molecular weight: 52,000, manufactured by Mitsui Chemicals, Inc., trade name: Unitol H-200
Polyfunctional epoxy compound (1): hydrogenated bisphenol A diglycidyl ether, manufactured by Kyoeisha Chemical Co., Ltd., trade name: Epolite 4000, molecular weight: 470, epoxy equivalent: 235 g / eq
Polyfunctional epoxy compound (2): Dimethyloltricyclodecanediglycidyl ether, manufactured by ADEKA Corporation, trade name: ADEKA REGIN, EP-4088L, molecular weight: 330, epoxy equivalent: 165 g / eq
Polyfunctional epoxy compound (3): hydrogenated bisphenol A diglycidyl ether, manufactured by Mitsubishi Chemical Corporation, trade name: jER YX8034, molecular weight: 540, epoxy equivalent: 270 g / eq
Imidazole-based curing accelerator (1): 2-ethyl-4-methylimidazole, manufactured by Shikoku Chemicals Corporation, trade name: Curesol 2E4MZ
Silane coupling agent (1): 8-glycidoxyoctyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM4803
Silane coupling agent (2): 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM403

[Example 1]
Add 100 parts of acid-modified polyolefin resin (1), 25 parts of polyfunctional epoxy compound (1), 0.25 part of imidazole-based curing accelerator, and 0.1 part of silane coupling agent (1) to methyl ethyl ketone. It was dissolved to prepare an adhesive composition (1) having a solid content concentration of 18%.
This adhesive composition (1) is applied onto the peeled surface of a release film (manufactured by Lintec Corporation, trade name: SP-PET382150), and the obtained coating film is dried at 100 ° C. for 2 minutes to increase the thickness. A 20 μm adhesive layer was formed, and a peeling-treated surface of another release film (manufactured by Lintec Corporation, trade name: SP-PET381031) was bonded thereto to obtain a sealing sheet (1).

[Example 2]
A sealing sheet (2) was obtained in the same manner as in Example 1 except that the polyfunctional epoxy compound (2) was used instead of the polyfunctional epoxy compound (1).

[Example 3]
A sealing sheet (3) was obtained in the same manner as in Example 1 except that the polyfunctional epoxy compound (3) was used instead of the polyfunctional epoxy compound (1).

[Example 4]
A sealing sheet (4) was obtained in the same manner as in Example 1 except that the silane coupling agent (2) was used instead of the silane coupling agent (1) in Example 1.

[Comparative Example 1]
In Example 1, a sealing sheet (5) was obtained in the same manner as in Example 1 except that a silane coupling agent was not used.

[Comparative Example 2]
In Example 2, a sealing sheet (6) was obtained in the same manner as in Example 2 except that a silane coupling agent was not used.

[Comparative Example 3]
A sealing sheet (7) was obtained in the same manner as in Example 1 except that the polyfunctional epoxy compound and the imidazole-based curing catalyst were not used.

The following tests were performed on the sealing sheets (1) to (7) obtained in Examples 1 to 4 and Comparative Examples 1 to 3.
[Preparation of test piece]
An adhesive layer exposed by peeling off one release film of a sealing sheet having a width of 25 mm was layered on a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., trade name "Cosmo Shine PET50A4300") having a thickness of 50 μm and a width of 25 mm. Next, another release film was peeled off and the exposed adhesive layer was placed on a glass plate and laminated under the conditions of a temperature of 60 ° C., a pressure of 0.2 MPa, and a speed of 0.2 m / min to obtain a pressure-bonded body. The obtained crimped body was heated at 100 ° C. for 2 hours to cure the adhesive layer, and two test pieces were obtained for each.
[Adhesive strength measurement]
As the peeling test (a), the test piece was subjected to a 180 ° peeling test under the conditions of a temperature of 23 ° C. and a relative humidity of 50%.
As a peeling test (b), the test piece was allowed to stand for 100 hours under the conditions of a temperature of 60 ° C. and a relative humidity of 90%, and then for 24 hours under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, and then the temperature was 23. A 180 ° peeling test was performed under the conditions of ° C. and relative humidity of 50%.
In this peeling test, except for the above-mentioned test conditions, the adhesive strength was measured according to the method for measuring the adhesive strength described in JIS Z0237: 2000.

[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 / □: ohms per square) was formed as an anode was produced by the following method.
First, on the ITO film of the glass substrate, N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) -benzidine (manufactured by Luminesis Technology) was placed at 50 nm and Tris (8-). Hydroxy-quinolinate) aluminum (manufactured by Luminesis Technology) was sequentially vapor-deposited at a rate of 50 nm and 0.1 to 0.2 nm / min to form a light emitting layer.
Lithium fluoride (LiF) (manufactured by High Purity Chemical Laboratory) was added to the obtained light emitting layer as an electron injection material at a rate of 0.1 nm / min at a rate of 4 nm, and then aluminum (Al) (High Purity Chemical Laboratory). A cathode was formed by vapor-depositing 100 nm at a rate of 0.1 nm / min to obtain an organic EL element.
The degree of vacuum at the time of vapor deposition was 1 × 10 ^-4 Pa or less.

One release film of the sealing sheet obtained in Examples or Comparative Examples was peeled off, an exposed adhesive layer was layered on a metal foil film, and these were bonded at 60 ° C. using a heat laminator. Next, another release film was peeled off, the exposed adhesive layer was layered so as to cover the organic EL element formed on the glass substrate, and these were bonded 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 an organic EL element was sealed.
After allowing this electronic device to stand in an environment with a temperature of 60 ° C. and a relative humidity of 90% for 250 hours, the organic EL element is activated, the presence or absence of dark spots (non-light emitting parts) is observed, and the evaluation is made according to the following criteria. bottom.
⊚: Dark spot is less than 40% of the light emitting area ○: Dark spot is 40% or more and less than 50% of the light emitting area ×: Dark spot is 50% or more of the light emitting area

The following can be seen from Table 1.
The sealing sheets of Examples 1 to 4 maintain excellent adhesive strength even after being allowed to stand under high temperature and high humidity conditions (60 ° C., relative humidity 90%, standing for 100 hours), and have excellent sealing properties. There is.
On the other hand, when the sealing sheets of Comparative Examples 1 to 3 are placed under high temperature and high humidity conditions (60 ° C., relative humidity 90%, standing for 100 hours), the adhesive strength is greatly reduced and the sealing performance is inferior. There is.

Claims (12)

The following components (A), (B), (C), and (D) component (A) component: modified polyolefin resin (B) component: polyfunctional epoxy compound (C) component: curing accelerator (D) ) Ingredient: Silane coupling agent represented by the following formula (2)

(R ¹ represents an alkylene group having 4 to 15 carbon atoms, R ² represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, R ³ represents an alkyl group having 1 to 4 carbon atoms, and Z represents an epoxy. Represents a group having a group, where n is 0 or 1).
When a 180 ° peeling test is performed on a test piece obtained by using this adhesive composition, the x value calculated by the following formula (1) is 1. An adhesive composition characterized by being 3 or less.

(In the formula, a represents the adhesive force obtained by performing a 180 ° peeling test under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, and b represents a condition of the test piece having a temperature of 60 ° C. and a relative humidity of 90%. Adhesive strength obtained by performing a 180 ° peeling test under the conditions of a temperature of 23 ° C. and a relative humidity of 50% after allowing the material to stand under the conditions of a temperature of 23 ° C. and a relative humidity of 50% for 24 hours. In these 180 ° peeling test test pieces, a sealing sheet composed of an adhesive layer having a thickness of 20 μm and a polyethylene terephthalate film having a thickness of 50 μm obtained by using an adhesive composition is formed on the adhesive layer. One side is placed on a glass plate and laminated under the conditions of a temperature of 60 ° C., a pressure of 0.2 MPa and a speed of 0.2 m / min, and then the obtained crimped body is heated at 100 ° C. for 2 hours to bond the obtained crimped body. It is a laminated body having a width of 25 mm obtained by curing the agent layer.) The adhesive composition according to claim 1, wherein the component (A) is an acid-modified polyolefin resin. The adhesive composition according to claim 1 or 2, wherein the content of the component (B) is 10 to 50 parts by mass with respect to 100 parts by mass of the component (A). The adhesive composition according to any one of claims 1 to 3, wherein the component (C) is an imidazole-based curing accelerator. The adhesive composition according to any one of claims 1 to 4, wherein the content of the component (C) is 0.1 to 10 parts by mass with respect to 100 parts by mass of the component (A). The adhesive composition according to any one of claims 1 to 5 , wherein the content of the component (D) is 0.05 to 5 parts by mass with respect to 100 parts by mass of the component (A). A sealing sheet composed of two release films and an adhesive layer sandwiched between these release films.
A sealing sheet in which the adhesive layer is formed by using the adhesive composition according to any one of claims 1 to 6 . A sealing sheet composed of a release film, a gas barrier film, and an adhesive layer sandwiched between the release film and the gas barrier film.
A sealing sheet in which the adhesive layer is formed by using the adhesive composition according to any one of claims 1 to 6 . The sealing sheet according to claim 8 , wherein the gas barrier film is a metal foil, a resin film, or a thin film glass. The sealing sheet according to any one of claims 7 to 9 , wherein the adhesive layer has a thickness of 1 to 50 μm. A sealed body in which the material to be sealed is sealed using the sealing sheet according to any one of claims 7 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.