JP7239579B2 - Adhesive sheet for device encapsulation and method for manufacturing device encapsulation - Google Patents

Description

The present invention provides a device-sealing adhesive sheet having two release films and an adhesive layer sandwiched between the release films, and a device-sealing body using this device-sealing adhesive sheet. Regarding the method.

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 the luminescence characteristics such as luminance, luminous efficiency, and luminous uniformity tend to deteriorate over time.
As a cause of the problem of deterioration of the luminescence characteristics, it is thought that oxygen, moisture, etc. enter the inside of the organic EL element and deteriorate the electrodes and the organic layer. For this reason, it has been proposed to solve this problem by forming a sealing material using a pressure-sensitive adhesive layer or an adhesive layer having excellent moisture barrier properties.

For example, Patent Document 1 describes a sheet-like sealing material containing a specific epoxy resin, a specific alicyclic epoxy compound, a thermal cationic polymerization initiator, a photocationic polymerization initiator, and a specific sensitizer. ing.
A sealing material formed using the sheet-like sealing material described in Patent Document 1 has low oxygen permeability and low moisture permeability, and has good sealing performance.

JP 2018-95679 A

However, it has been found that a new problem may occur when forming a sealing material using an adhesive layer as in Patent Document 1.
That is, the adhesive layer is usually manufactured and stored in a state sandwiched between two release films, and the release film is peeled off when used. The agent layer sometimes ruptured.

The present invention has been made for the purpose of solving this problem, and has two release films and an adhesive layer sandwiched between these release films, without tearing the adhesive layer. An object of the present invention is to provide a device-sealing adhesive sheet from which a release film can be peeled off, and a method for producing a device-sealed body using the device-sealing adhesive sheet.

In order to solve the above problems, the present inventors have developed an adhesive sheet for device sealing having two release films and an adhesive layer sandwiched between the release films and containing a compound having a cyclic ether group. I studied hard.
As a result, by satisfying both the requirements regarding the storage modulus of the adhesive layer at 23° C. and the requirements regarding the peel strength of the two peeling films, the device can peel the peeling films without tearing the adhesive layer. The inventors have found that an adhesive sheet for sealing can be obtained, and have completed the present invention.

Thus, according to the present invention, there are provided the following adhesive sheets for device encapsulation of [1] to [9] and a method for producing a device encapsulant of [10].

[1] A device sealing adhesive sheet having a first release film and a second release film, and an adhesive layer sandwiched between the first release film and the second release film, wherein the following requirements (I): ~ A device encapsulating adhesive sheet that satisfies all requirements (III).
Requirement (I): The adhesive layer is a layer containing one or more compounds having a cyclic ether group.
Requirement (II): The storage elastic modulus at 23° C. of the adhesive layer is 5.0×10 ⁵ Pa or more and 3.0×10 ⁷ Pa or less.
Requirement (III): The value of the peeling force between the first peeling film and the adhesive layer is represented by x (mN/50 mm), and the value of the peeling force between the second peeling film and the adhesive layer is When expressed as y (mN/50 mm), the device sealing adhesive sheet satisfies the following formula (1).

[2] The adhesive sheet for device encapsulation according to [1], wherein at least one compound having a cyclic ether group is a compound that is liquid at 25°C.
[3] The adhesive sheet for device sealing according to [2], wherein the content of the compound having a cyclic ether group, which is liquid at 25°C, is 53% by mass or more relative to the entire adhesive layer.
[4] The adhesive sheet for device sealing according to any one of [1] to [3], wherein the adhesive layer further contains a thermal cationic polymerization initiator.
[5] The adhesive sheet for device encapsulation of [4], wherein at least one of the compounds having a cyclic ether group is a compound having a glycidyl ether group.
[6] The adhesive sheet for device encapsulation according to any one of [1] to [5], wherein the adhesive layer further contains a binder resin.
[7] The adhesive sheet for device encapsulation of [6], wherein the binder resin has a glass transition temperature of 90°C or higher.
[8] The adhesive for device sealing according to any one of [1] to [7], wherein the layer obtained by curing the adhesive layer has a storage elastic modulus at 90° C. of 1×10 ⁸ Pa or more. sheet.
[9] The adhesive sheet for device sealing according to any one of [1] to [8], wherein the value x of the peeling force between the first peeling film and the adhesive layer is 30 to 200 mN/50 mm.
[10] A step of peeling the second release film from the device sealing adhesive sheet according to any one of [1] to [9], and sealing the exposed adhesive layer in a temperature environment of 20 to 30°C. A method of manufacturing a device sealing body, including a step of attaching to an object or substrate.

ADVANTAGE OF THE INVENTION According to this invention, it has two peeling films and the adhesive layer pinched by these peeling films, The adhesive for device sealing which can peel a peeling film, without tearing an adhesive layer. Provided are a sheet and a method for producing a device sealing body using the device sealing adhesive sheet.

The device sealing adhesive sheet of the present invention is a device sealing adhesive sheet comprising a first release film, a second release film, and an adhesive layer sandwiched between the first release film and the second release film. It satisfies all of the requirements (I), (II), and (III) above.

In the present invention, the "first release film" refers to the two release films having the highest release force, and the "second release film" refers to the two release films having the lowest release force. say.
The "adhesive layer" is a layer obtained by coating a curable adhesive and having curable, sticky, and adhesive properties. That is, the "adhesive layer" is a layer in an uncured state.
In this specification, "a layer obtained by curing an adhesive layer" may be referred to as a "cured adhesive layer". This cured adhesive layer is used as a sealing material.
In the present invention, "curing" means that the cyclic ether groups contained in the adhesive layer react to increase the cohesive strength and storage elastic modulus of the layer.

[Adhesive layer]
(Compound having a cyclic ether group)
The adhesive layer contains one or more compounds having a cyclic ether group (hereinafter sometimes referred to as "cyclic ether compound (A)").
By curing the adhesive layer containing the cyclic ether compound (A), a sealing material having high adhesive strength and excellent water vapor barrier properties can be formed.

The cyclic ether compound (A) refers to a compound having at least one, preferably two or more cyclic ether groups in the molecule. In the present invention, the phenoxy resin described later shall not be included in the cyclic ether compound (A).

The molecular weight of the cyclic ether compound (A) is generally 100-5,000, preferably 200-3,000.
The cyclic ether equivalent weight of the cyclic ether compound (A) is preferably 50-1000 g/eq, more preferably 100-800 g/eq.
By curing the adhesive layer containing the cyclic ether compound (A) having a cyclic ether equivalent within the above range, it is possible to more efficiently form a sealant having higher adhesive strength and superior moisture barrier properties.
The cyclic ether equivalent in the present invention means the value obtained by dividing the molecular weight by the number of cyclic ether groups.

The cyclic ether group includes an oxirane group (epoxy group), an oxetane group (oxetanyl group), a tetrahydrofuryl group, a tetrahydropyranyl group and the like. Among these, the cyclic ether group is preferably an oxirane group or an oxetane group, more preferably an oxirane group, from the viewpoint that a sealing material having higher adhesive strength can be formed.
For the same reason, the cyclic ether compound (A) preferably has two or more oxirane groups or oxetane groups in its molecule, more preferably two or more oxirane groups in its molecule.

Examples of compounds having an oxirane group in the molecule include aliphatic epoxy compounds (excluding alicyclic epoxy compounds), aromatic epoxy compounds, and alicyclic epoxy compounds.
Examples of aliphatic epoxy compounds include monofunctional epoxy compounds such as glycidyl ethers of aliphatic alcohols and glycidyl esters of alkylcarboxylic acids;
polyfunctional epoxy compounds such as aliphatic polyhydric alcohols, polyglycidyl ethers of alkylene oxide adducts thereof, and polyglycidyl esters of aliphatic long-chain polybasic acids;

Representative compounds of these aliphatic epoxy compounds include alkenyl glycidyl ethers such as allyl glycidyl ether; alkyl glycidyl ethers such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, C12-13 mixed alkyl glycidyl ether; Butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, tetraglycidyl ether of sorbitol, hexaglycidyl ether of dipentaerythritol, diglycidyl ether of polyethylene glycol, polypropylene glycol diglycidyl ether of polyhydric alcohol such as diglycidyl ether of dicyclopentadiene dimethanol diglycidyl ether; propylene glycol, trimethylolpropane, aliphatic polyhydric alcohol such as glycerin with one or more alkylene oxides added Diglycidyl esters of aliphatic long-chain dibasic acids; monoglycidyl ethers of aliphatic higher alcohols, glycidyl esters of higher fatty acids, epoxidized soybean oil, octyl epoxystearate, Butyl epoxy stearate, epoxidized polybutadiene; and the like.

Moreover, a commercial item can also be used as an aliphatic epoxy compound. Commercially available products include Denacol EX-121, Denacol EX-171, Denacol EX-192, Denacol EX-211, Denacol EX-212, Denacol EX-313, Denacol EX-314, Denacol EX-321, Denacol EX-411, Denacol EX-421, Denacol EX-512, Denacol EX-521, Denacol EX-611, Denacol EX-612, Denacol EX-614, Denacol EX-622, Denacol EX-810, Denacol EX-811, Denacol EX-850, Denacol EX-851, Denacol EX-821, Denacol EX-830, Denacol EX-832, Denacol EX-841, Denacol EX-861, Denacol EX-911, Denacol EX-941, Denacol EX-920, Denacol EX-931 ( Above, manufactured by Nagase ChemteX Corporation);
Epolite M-1230, Epolite 40E, Epolite 100E, Epolite 200E, Epolite 400E, Epolite 70P, Epolite 200P, Epolite 400P, Epolite 1500NP, Epolite 1600, Epolite 80MF, Epolite 100MF (manufactured by Kyoeisha Chemical Co., Ltd.);
ADEKA GLYCIROL ED-503, ADEKA GLYCIROL ED-503G, ADEKA GLYCIROL ED-506, ADEKA GLYCIROL ED-523T (manufactured by ADEKA);

Examples of aromatic epoxy compounds include phenols having at least one aromatic ring, such as phenol, cresol, and butylphenol, or mono/polyglycidyl etherified products of alkylene oxide adducts thereof; epoxy compounds having an aromatic heterocycle; is mentioned.
Representative compounds of these aromatic epoxy compounds include bisphenol A, bisphenol F, or glycidyl etherified compounds obtained by adding alkylene oxide to these compounds, and epoxy novolak resins;
mono/polyglycidyl etherates of aromatic compounds having two or more phenolic hydroxyl groups such as resorcinol, hydroquinone, catechol;
glycidyl etherified aromatic compounds having two or more alcoholic hydroxyl groups such as phenyldimethanol, phenyldiethanol, and phenyldibutanol;
Glycidyl esters of polybasic aromatic compounds having two or more carboxylic acids such as phthalic acid, terephthalic acid, trimellitic acid, glycidyl esters of benzoic acid, epoxidized products of styrene oxide or divinylbenzene;
epoxy compounds having a triazine skeleton such as 2,4,6-tri(glycidyloxy)-1,3,5-triazine;

Moreover, a commercial item can also be used as an aromatic epoxy compound. Commercially available products include Denacol EX-146, Denacol EX-147, Denacol EX-201, Denacol EX-203, Denacol EX-711, Denacol EX-721, Oncoat EX-1020, Oncoat EX-1030, and Oncoat EX. -1040, Oncoat EX-1050, Oncoat EX-1051, Oncoat EX-1010, Oncoat EX-1011, Oncoat 1012 (manufactured by Nagase ChemteX Corporation);
Ogsol PG-100, Ogsol EG-200, Ogsol EG-210, Ogsol EG-250 (manufactured by Osaka Gas Chemicals Co., Ltd.);
HP4032, HP4032D, HP4700 (manufactured by DIC Corporation);
ESN-475V (manufactured by Nippon Steel Chemical & Materials Co., Ltd.);
JER (former Epicote) YX8800 (manufactured by Mitsubishi Chemical Corporation);
Marproof G-0105SA, Marproof G-0130SP (manufactured by NOF Corporation);
Epiclon N-665, Epiclon HP-7200 (manufactured by DIC);
EOCN-1020, EOCN-102S, EOCN-103S, EOCN-104S, XD-1000, NC-3000, EPPN-501H, EPPN-501HY, EPPN-502H, NC-7000L (manufactured by Nippon Kayaku Co., Ltd.);
ADEKA RESIN EP-4000, ADEKA RESIN EP-4005, ADEKA RESIN EP-4100, ADEKA RESIN EP-4901 (manufactured by ADEKA);
TECHMORE VG-3101L (manufactured by Printec);
TEPIC-FL, TEPIC-PAS, TEPIC-UC (manufactured by Nissan Chemical Industries, Ltd.);

The alicyclic epoxy compounds include polyglycidyl ethers of polyhydric alcohols having at least one or more alicyclic structures, or cyclohexene oxides and cyclopentenes obtained by epoxidizing compounds containing cyclohexene or cyclopentene rings with an oxidizing agent. Oxide-containing compounds can be mentioned.
Representative compounds of these alicyclic epoxy compounds include hydrogenated bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 3,4-epoxy-1-methylcyclohexyl. -3,4-epoxy-1-methylhexanecarboxylate, 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-3-methylcyclohexylmethyl -3,4-epoxy-3-methylcyclohexanecarboxylate, 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl)adipate , 3,4-epoxy-6-methylcyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane), propane-2,2-diyl-bis(3,4-epoxycyclohexane), 2,2-bis(3, 4-epoxycyclohexyl)propane, dicyclopentadiene diepoxide, ethylenebis(3,4-epoxycyclohexanecarboxylate), dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1-epoxyethyl-3 ,4-epoxycyclohexane, 1,2-epoxy-2-epoxyethylcyclohexane, α-pinene oxide, limonene dioxide and the like.

Moreover, a commercial item can also be used as an alicyclic epoxy compound. Commercially available products include Celoxide 2021P, Celoxide 2081, Celoxide 2000, and Celoxide 3000 (manufactured by Daicel Corporation); Epolite 4000 (manufactured by Kyoeisha Chemical Co., Ltd.); YX8000 and YX8034 (manufactured by Mitsubishi Chemical Corporation); ADEKA RESIN EP-4088L, ADEKA RESIN EP-4080E (manufactured by ADEKA);

Further, examples of compounds having an oxirane group in the molecule include epoxy compounds having both an alicyclic structure and an aromatic ring in one molecule. Such compounds include, for example, Epiclon HP-7200 (manufactured by DIC).

Among these, alicyclic epoxy resins are preferable as the compound having an oxirane group from the viewpoint of lowering the dielectric constant of the cured adhesive layer.
Moreover, when a thermal cationic polymerization initiator is used as a curing catalyst, which will be described later, the compound having an oxirane group is preferably a compound having a glycidyl ether group. A glycidyl ether group undergoes a cationic polymerization reaction relatively mildly. Therefore, when the manufacturing process of the adhesive layer includes a step of heating a composition containing components constituting the adhesive layer (for example, a step of heating to 90 ° C. or higher), the polymerization reaction of the glycidyl ether group is difficult to proceed. , it is easy to keep the storage modulus of the adhesive layer at 23° C. low. The content of the compound having a glycidyl ether group is preferably 70% by mass or more, more preferably 90% by mass or more, relative to the entire compound having a cyclic ether group.

Compounds having an oxetane group in the molecule include 3,7-bis(3-oxetanyl)-5-oxa-nonane, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 1, 2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]ethane, 1,3-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl-3-oxetanylmethyl) ) ether, triethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, 1,4-bis(3-ethyl-3-oxetanylmethoxy) Butane, bifunctional aliphatic oxetane compounds such as 1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, 3-ethyl-3-[(phenoxy)methyl]oxetane, 3-ethyl-3-(hexyloxy methyl)oxetane, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, 3-ethyl-3-(hydroxymethyl)oxetane, 3-ethyl-3-(chloromethyl)oxetane and other monofunctional oxetane compounds, etc. is mentioned.

A commercially available product can also be used as the compound having an oxetane group in the molecule. Commercially available products include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, and 4-hydroxybutyl vinyl ether (manufactured by Maruzen Petrochemical Co., Ltd.);
Aron oxetane OXT-121, OXT-221, EXOH, POX, OXA, OXT-101, OXT-211, OXT-212 (manufactured by Toagosei Co., Ltd.);
ETANACOL OXBP, OXTP (manufactured by Ube Industries, Ltd.) and the like.

These cyclic ether compounds (A) can be used singly or in combination of two or more.

The content of the cyclic ether compound (A) in the adhesive layer (the total amount of these when two or more cyclic ether compounds (A) are included) is preferably 45 to 90 mass with respect to the entire adhesive layer. %, more preferably 50 to 85% by mass, still more preferably 60 to 80% by mass.
By setting the content of the cyclic ether compound (A) within the above range, it becomes easier to obtain a cured adhesive layer having a high storage elastic modulus at 90°C.

At least one of the cyclic ether compounds (A) in the adhesive layer is preferably a compound that is liquid at 25°C (a cyclic ether compound (AL) that is liquid at 25°C). Here, the term "liquid" refers to a state in which substances are aggregated and have a substantially constant volume but no peculiar shape.
By using a cyclic ether compound (AL) that is liquid at 25°C, it is possible to prevent the storage modulus of the adhesive layer at 23°C from becoming too high. Therefore, it becomes easy to obtain an adhesive layer having sufficient adhesive strength around room temperature (meaning 20 to 30° C.; the same shall apply hereinafter).

From the viewpoint of adjusting the storage modulus of the adhesive layer at 23°C, the cyclic ether equivalent of the cyclic ether compound (AL) that is liquid at 25°C is preferably 150 to 1000 g/eq, more preferably 240 to 900 g/eq. be.

The content of the cyclic ether compound (AL) that is liquid at 25°C in the adhesive layer (the total amount of these when two or more compounds are included) is preferably 53% by mass based on the entire adhesive layer. Above, more preferably 53 to 80 mass %, still more preferably 54 to 65 mass %. When the content of the cyclic ether compound (AL) that is liquid at 25° C. is 53% by mass or more relative to the entire adhesive layer, it becomes easier to obtain an adhesive layer having sufficient adhesive strength around room temperature. In addition, it becomes easier to obtain a cured adhesive layer having a high storage elastic modulus at 90°C. In addition, when the content of the cyclic ether compound (AL) that is liquid at 25°C is 80% by mass or less with respect to the entire adhesive layer, the storage elastic modulus of the adhesive layer at 23°C can be easily increased.

(binder resin)
The adhesive layer may contain a binder resin (B). An adhesive layer containing a binder resin is excellent in shape retention and handleability.

The weight-average molecular weight (Mw) of the binder resin (B) is not particularly limited, but is preferably 10,000 or more, more preferably 10,000 or more, because it has excellent compatibility with the cyclic ether compound (A) and excellent shape retention. is 10,000 to 150,000, more preferably 10,000 to 100,000.
The weight average molecular weight (Mw) of the binder resin can be obtained as a standard polystyrene conversion value by performing gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

When the adhesive layer contains the binder resin (B), the content of the binder resin (the total amount of these when two or more binder resins are included) is preferably 5 to 50 with respect to the entire adhesive layer. % by mass, more preferably 10 to 45% by mass.
When the content of the binder resin (B) is within the above range, it becomes easy to obtain an adhesive layer that is excellent in shape retention and has sufficient adhesive strength.

As will be described later, when the storage elastic modulus of the cured adhesive layer at 90° C. is 1×10 ⁸ Pa or higher, the binder resin (B) is a resin having a glass transition temperature of 90° C. or higher. It is preferable because the storage elastic modulus of the cured material layer at 90° C. is likely to increase. Examples of resins having a glass transition temperature of 90° C. or higher include some phenoxy-based resins, polyimide-based resins, polyamide-imide-based resins, polyvinyl butyral-based resins, polycarbonate-based resins, and the like. Examples of resins having a glass transition temperature of less than 90° C. include acrylic resins, urethane resins, and olefin resins.
These resins can be used singly or in combination of two or more.

The binder resin (B) is preferably at least one selected from the group consisting of phenoxy-based resins and modified olefin-based resins. Resin is preferred.

A phenoxy-based resin generally corresponds to a high-molecular-weight epoxy resin and has a degree of polymerization of about 100 or more.

The phenoxy resin used in the present invention preferably has a weight average molecular weight (Mw) of 10,000 to 150,000, more preferably 10,000 to 100,000. The weight-average molecular weight (Mw) of the phenoxy-based resin can be obtained as a standard polystyrene conversion value by performing gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.
A phenoxy-based resin corresponding to such a high-molecular-weight epoxy resin is excellent in heat deformation resistance.
The epoxy equivalent of the phenoxy resin used in the present invention is preferably 5,000 or more, more preferably 7,000 or more. The epoxy equivalent value can be measured according to JIS K7236.

The phenoxy resins used in the present invention include bisphenol A type, bisphenol F type, bisphenol S type phenoxy resins, copolymer type phenoxy resins of bisphenol A type and bisphenol F type phenoxy resins, distilled products thereof, naphthalene type phenoxy resins, novolac type phenoxy resins, resins, biphenyl-type phenoxy resins, cyclopentadiene-type phenoxy resins, and the like.
These phenoxy resins can be used singly or in combination of two or more.

A phenoxy-based resin can be obtained by a method of reacting a bifunctional phenol with epihalohydrin to a high molecular weight, or by a polyaddition reaction of a bifunctional epoxy resin and a bifunctional phenol.
For example, it can be obtained by reacting a bifunctional phenol with epihalohydrin in the presence of an alkali metal hydroxide in an inert solvent at a temperature of 40 to 120°C. In addition, a bifunctional epoxy resin and a bifunctional phenol are mixed in an amide solvent, ether solvent, It can also be obtained by heating to 50 to 200° C. in an organic solvent such as a ketone solvent, a lactone solvent, an alcohol solvent, etc. at a reaction solid content concentration of 50% by weight or less to carry out a polyaddition reaction.

Bifunctional phenols are not particularly limited as long as they are compounds having two phenolic hydroxyl groups. For example, monocyclic bifunctional phenols such as hydroquinone, 2-bromohydroquinone, resorcinol and catechol; bisphenols such as bisphenol A, bisphenol F, bisphenol AD and bisphenol S; dihydroxybiphenyls such as 4,4'-dihydroxybiphenyl; Dihydroxyphenyl ethers such as bis(4-hydroxyphenyl) ether; and linear alkyl groups, branched alkyl groups, aryl groups, methylol groups, allyl groups, cycloaliphatic groups, halogen ( tetrabromobisphenol A, etc.), those introduced with a nitro group, etc.; linear alkyl groups, branched alkyl groups, allyl groups, allyl groups with substituents on the central carbon atoms of these bisphenol skeletons, and cycloaliphatic groups group, polycyclic bifunctional phenols into which an alkoxycarbonyl group or the like is introduced; and the like.

Epihalohydrin includes epichlorohydrin, epibromhydrin, epiiodohydrin and the like.

Moreover, in this invention, a commercial item can also be used as a phenoxy-type resin. For example, Mitsubishi Chemical Corp. trade names: YX7200 (glass transition temperature: 150°C), YX6954 (bisphenolacetophenone skeleton-containing phenoxy resin, glass transition temperature: 130°C), YL7553, YL6794, YL7213, YL7290, YL7482, YX8100 (bisphenol S skeleton-containing phenoxy resin), trade names manufactured by Toto Kasei: FX280, FX293, FX293S (fluorene skeleton-containing phenoxy resin), trade names manufactured by Mitsubishi Chemical Corporation: jER1256, jER4250 (glass transition temperature: less than 85 ° C.), jER4275 (Glass transition temperature: 75 ° C.), trade name manufactured by Nippon Steel Chemical & Materials: YP-50 (glass transition temperature: 84 ° C.), YP-50S (both phenoxy resins containing bisphenol A skeleton), YP-70 ( bisphenol A skeleton/bisphenol F skeleton copolymer type phenoxy resin, glass transition temperature: less than 85° C.), ZX-1356-2 (glass transition temperature: 72° C.), and the like. In addition, the glass transition temperature was shown about the thing with the known glass transition temperature.

The modified olefinic resin is an olefinic resin into which a functional group is introduced, which is obtained by subjecting an olefinic resin as a precursor to a modification treatment using a modifying agent.

An olefinic resin refers to a polymer containing repeating units derived from an olefinic monomer. The olefin-based resin may be a polymer consisting only of repeating units derived from an olefin-based monomer, or 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 repeating units derived from

The olefinic 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 olefinic monomers can be used singly or in combination of two or more.
Examples of monomers copolymerizable with olefinic monomers include vinyl acetate, (meth)acrylic acid esters, and styrene. Here, "(meth)acrylic acid" means acrylic acid or methacrylic acid (same below).
These olefin-based monomers and copolymerizable monomers can be used singly or in combination of two or more.

Olefin resins include 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 Copolymers, olefinic elastomers (TPO), ethylene-vinyl acetate copolymers (EVA), ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, and the like.

A modifier used for modification treatment of an olefin resin is a compound having a functional group in its molecule.
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, ether group. , thioether group, sulfone group, phosphone group, nitro group, urethane group, alkoxysilyl group, silanol group, halogen atom and the like. A compound having a functional group may have two or more functional groups in the molecule.

As the modified olefin resin, an acid-modified olefin resin is preferable.
An acid-modified olefin resin is an olefin resin graft-modified with an acid or an acid anhydride. For example, an olefin resin is reacted with an unsaturated carboxylic acid or an unsaturated carboxylic anhydride (hereinafter sometimes referred to as "unsaturated carboxylic acid, etc.") to introduce a carboxyl group or a carboxylic anhydride group (grafting denatured).

Unsaturated carboxylic acids to be reacted with the olefin resin include unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, and aconitic acid; maleic anhydride, itaconic anhydride, unsaturated carboxylic anhydrides such as glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornenedicarboxylic anhydride, and tetrahydrophthalic anhydride;
These can be used individually by 1 type or in combination of 2 or more types. Among these, maleic anhydride is preferable because a sealing material having higher adhesive strength can be easily obtained.

The amount of the unsaturated carboxylic acid or the like to be reacted with the olefin resin is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, and still more preferably 0 parts by mass with respect to 100 parts by mass of the olefin resin. .2 to 1 part by mass. By curing the adhesive layer containing the acid-modified olefin-based resin thus obtained, a sealing material having higher adhesive strength can be formed.

The method of introducing unsaturated carboxylic acid units or unsaturated carboxylic anhydride units into the olefinic resin is not particularly limited. For example, in the presence of a radical generator such as organic peroxides or azonitriles, an olefinic resin and an unsaturated carboxylic acid are heated and melted above the melting point of the olefinic resin to react, or an olefin After dissolving the system resin and unsaturated carboxylic acid etc. in an organic solvent, the unsaturated carboxylic acid etc. is graft-copolymerized with the olefinic resin by a method such as heating and stirring in the presence of a radical generator to cause a reaction. method.

Commercially available products can also be used as the acid-modified olefin resin. Examples of commercially available products include ADMER (registered trademark) (manufactured by Mitsui Chemicals, Inc.), Unistol (registered trademark) (manufactured by Mitsui Chemicals, Inc.), BondyRam (manufactured by Polyram), orevac (registered trademark) (manufactured by ARKEMA), Modic (registered trademark) (manufactured by Mitsubishi Chemical Corporation) and the like.

The weight average molecular weight (Mw) of the modified olefin resin is preferably 10,000 to 150,000, more preferably 30,000 to 100,000.
The weight average molecular weight (Mw) of the modified olefin resin can be obtained as a standard polystyrene conversion value by performing gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

(Curing catalyst)
The adhesive layer may contain a curing catalyst. A curing catalyst is used to accelerate the reaction of the cyclic ether groups in the cyclic ether compound (A).
Curing catalysts include anionic polymerization initiators and cationic polymerization initiators.
A cationic polymerization initiator is preferable from the viewpoint of promoting the curing reaction in a short time and improving the storage stability of the adhesive layer.

Examples of anionic polymerization initiators include 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 other imidazole curing catalysts.

Examples of cationic polymerization initiators include thermal cationic polymerization initiators and photocationic polymerization initiators, which can be used even when it is difficult to irradiate the adhesive layer with light due to the manufacturing process of the device sealing body. A thermal cationic polymerization initiator is preferred from the viewpoint of versatility of thermosetting equipment.

Thermal cationic polymerization initiators are compounds that can generate cationic species that initiate polymerization by heating.
Thermal cationic polymerization initiators include sulfonium salts, quaternary ammonium salts, phosphonium salts, diazonium salts, iodonium salts and the like. Among these, sulfonium salts are preferable from the viewpoints of easy availability and easy availability of a sealing material having excellent adhesiveness and transparency.

Sulfonium salts include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroalcinate, tris(4-methoxyphenyl)sulfonium hexafluoroalcinate, and diphenyl(4-phenylthiophenyl)sulfonium. hexafluoroalcinate and the like.

Moreover, a commercial item can also be used as a sulfonium salt. Commercially available products include Adeka Opton SP-150, Adeka Opton SP-170, Adeka Opton CP-66, Adeka Opton CP-77 (manufactured by ADEKA), San-Aid SI-60L, San-Aid SI-80L, and San-Aid SI-100L (three Shin Chemical Co., Ltd.), CYRACURE UVI-6974, CYRACURE UVI-6990 (manufactured by Union Carbide), UVI-508, UVI-509 (manufactured by General Electric), FC-508, FC-509 ( and CD-1010, CD-1011 (manufactured by Saastomer Co., Ltd.), CI series products (manufactured by Nippon Soda Co., Ltd.), and the like.

The quaternary ammonium salts include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium hydrogensulfate, tetraethylammonium tetrafluoroborate, tetraethylammonium p-toluenesulfonate, N,N-dimethyl-N- benzylanilinium hexafluoroantimonate, N,N-dimethyl-N-benzylanilinium tetrafluoroborate, N,N-dimethyl-N-benzylpyridinium hexafluoroantimonate, N,N-diethyl-N-benzyltrifluoromethanesulfonate , N,N-dimethyl-N-(4-methoxybenzyl)pyridinium hexafluoroantimonate, and N,N-diethyl-N-(4-methoxybenzyl)toluidinium hexafluoroantimonate. Examples of the phosphonium salts include ethyltriphenylphosphonium hexafluoroantimonate and tetrabutylphosphonium hexafluoroantimonate.

Examples of diazonium salts include AMERICURE (manufactured by American Can) and ULTRASET (manufactured by ADEKA).

Examples of iodonium salts include diphenyliodonium hexafluoroarsinate, bis(4-chlorophenyl)iodonium hexafluoroarsinate, bis(4-bromophenyl)iodonium hexafluoroarsinate, phenyl(4-methoxyphenyl)iodonium hexafluoroarsinate, and the like. is mentioned. In addition, as commercially available products, UV-9310C (manufactured by Toshiba Silicone Co., Ltd.), Photoinitiator 2074 (manufactured by Rhone-Poulenc), UVE series products (manufactured by General Electric Co.), FC series products (Minnesota Mining and Manufacturing company) can also be used.

A photocationic polymerization initiator is a compound capable of generating a cationic species that initiates polymerization upon irradiation with light.
Examples of photocationic polymerization initiators include aromatic sulfonium salts, aromatic iodonium salts, aromatic diazonium salts, thioxanthonium salts and the like.

Aromatic sulfonium salts are salts having an aromatic sulfonium as the cationic moiety. The anion portion includes anions such as BF ₄ ⁻ , PF ₆ ⁻ , and SbF ₆ ⁻ .
Examples of aromatic sulfonium salts include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, diphenyl-4-(phenylthio)phenylsulfonium hexafluorophosphate, diphenyl-4-(phenylthio)phenylsulfonium hexafluoroantimonate, and the like. mentioned.

Aromatic iodonium salts are salts having an aromatic iodonium as the cationic moiety. Examples of the anion portion include those similar to the anion portion of the aromatic sulfonium salt.
Aromatic iodonium salts include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis(pentafluorophenyl)borate, bis(dodecylphenyl)iodonium hexafluorophosphate, 4-methylphenyl -4-(1-methylethyl)phenyliodonium hexafluorophosphate and the like.

Aromatic diazonium salts are salts having an aromatic diazonium as the cationic moiety. Examples of the anion portion include those similar to the anion portion of the aromatic sulfonium salt.
Aromatic diazonium salts include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, phenyldiazonium tetrakis(pentafluorophenyl)borate and the like.

A thioxanthonium salt is a salt having a thioxanthonium as the cationic moiety. Examples of the anion portion include those similar to the anion portion of the aromatic sulfonium salt.
Thioxantonium salts include S-biphenyl-2-isopropylthioxanthonium hexafluorophosphate and the like.

The adhesive layer may contain one curing catalyst, or may contain two or more curing catalysts.
When the adhesive layer contains a curing catalyst, the content of the curing catalyst (the total amount of these when containing two or more curing catalysts) is not particularly limited, but is , preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass.

(Silane coupling agent)
The adhesive layer may contain a silane coupling agent. By curing the adhesive layer containing the silane coupling agent, it is possible to form a sealing material that is more excellent in wet heat durability.

A known silane coupling agent can be used as the silane coupling agent. Among them, organosilicon compounds having at least one alkoxysilyl group in the molecule are preferred.
Silane coupling agents include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltri Silane coupling agents having a (meth)acryloyl group such as methoxysilane and 8-methacryloxyoctyltrimethoxysilane;
Silane coupling agents having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, trichlorovinylsilane, vinyltris(2-methoxyethoxy)silane, 6-octenyltrimethoxysilane;
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 8-glycid Silane coupling agents having an epoxy group such as xyoctyltrimethoxysilane;
Silane coupling agents having a styryl group such as p-styryltrimethoxysilane and p-styryltriethoxysilane;
N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane , 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N - Silane coupling agents having an amino group such as hydrochloride of (vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane;
Silane coupling agents having a ureido group such as 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane;
Silane coupling agents having halogen atoms such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane;
Silane coupling agents having a mercapto group such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane;
Silane coupling agents having a sulfide group such as bis(trimethoxysilylpropyl)tetrasulfide and bis(triethoxysilylpropyl)tetrasulfide;
Silane coupling agents having an isocyanate group such as 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane;
Silane coupling agents having an allyl group such as allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane;
silane coupling agents having a hydroxyl group such as 3-hydroxypropyltrimethoxysilane and 3-hydroxypropyltriethoxysilane;
Among these, 8-methacryloxyoctyltrimethoxysilane, 6-octenyltrimethoxysilane, and 8-glycidoxyoctyl are used from the viewpoint of improving the adhesion of the adhesive layer to the surface of the device to be sealed. A long-chain spacer type silane coupling agent having an alkyl group having 4 to 8 carbon atoms between an alkoxysilyl group and an organic group, such as trimethoxysilane, is preferred.
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 (the total amount of these when two or more silane coupling agents are included) is preferably 0.00% in the entire adhesive layer. 01 to 5% by mass, more preferably 0.05 to 1% by mass.
The content of the silane coupling agent is preferably 0.01 to 10 parts by mass, more preferably 0.02 to 5 parts by mass, per 100 parts by mass of component (A).
When the content of the silane coupling agent is within the above range, it becomes easier to obtain a sealing agent having excellent wet heat durability.

(other ingredients)
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 UV absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, pigments, extenders, softeners and tackifiers.
These can be used individually by 1 type or in combination of 2 or more types.
When the adhesive layer contains these additives, the content thereof can be appropriately determined according to the purpose.

(adhesive layer)
The shape, size, etc. of the adhesive layer are not particularly limited. Further, it may be strip-shaped or elongated. As used herein, the term “long shape” refers to a shape having a length of 5 times or more, preferably 10 times or more, of the width, and is specifically wound into a roll. It refers to the shape of a film that is long enough to be taken and stored or transported. Although the upper limit of the ratio of the length to the width of the film is not particularly limited, it can be, for example, 100,000 times or less.

The thickness of the adhesive layer is usually 1-50 μm, preferably 1-25 μm, more preferably 5-25 μm. An adhesive layer having a thickness within the above range is suitably used as a material for forming a sealing material.
The thickness of the adhesive layer can be measured according to JIS K 7130 (1999) using a known thickness gauge.

The adhesive layer may have a single-layer structure, or may have a multi-layer structure (laminated with a plurality of adhesive layers).
The adhesive layer may have a uniform component, or may have a non-uniform component (for example, in the above adhesive layer having a multilayer structure, both components are mixed at the interface between the two adhesive layers). , an apparent single-layer structure).

The storage modulus of the adhesive layer at 23° C. is 5.0×10 ⁵ Pa or more, preferably 7.0×10 ⁵ Pa or more. When the storage elastic modulus of the adhesive layer at 23° C. is 5.0×10 ⁵ Pa or more, the release film can be peeled off without tearing the adhesive layer.
An adhesive layer having a storage modulus at 23° C. of 5.0×10 ⁵ Pa or more can be easily obtained by using, for example, a cyclic ether compound (A) having a large cyclic ether equivalent. Also, by reducing the content of the cyclic ether compound (AL) that is liquid at 25°C in the adhesive layer, the storage modulus of the adhesive layer at 23°C can be lowered. Furthermore, by using a relatively rigid resin such as a phenoxy resin, even if the content of the cyclic ether compound (AL) that is liquid at 25°C in the adhesive layer is large, storage at 23°C An adhesive layer having an elastic modulus of 5.0×10 ⁵ Pa or more can be easily obtained.

The storage modulus of the adhesive layer at 23° C. is 3.0×10 ⁷ Pa or less, preferably 2.0×10 ⁷ Pa or less, and more preferably 1.5×10 ⁷ Pa or less. An adhesive layer having a storage elastic modulus of 3.0×10 ⁷ Pa or less at 23° C. has sufficient adhesive strength at room temperature, and therefore has excellent adherability to an object to be sealed at room temperature.
An adhesive layer having a storage modulus of 3.0×10 ⁷ Pa or less at 23° C. can be easily obtained by increasing the amount of the cyclic ether compound (AL), which is liquid at 25° C., for example. Further, as described above, when the adhesive layer contains a thermal cationic polymerization initiator, the cyclic ether compound (A) is a compound having a glycidyl ether group, so that the adhesive layer can be stored at 23 ° C. The elastic modulus is lowered, and it becomes easy to make it 3.0×10 ⁷ Pa or less.

The storage elastic modulus of the adhesive layer can be measured using a known dynamic viscoelasticity measuring device.
Specifically, it can be measured by the method described in Examples.

The adhesive layer has curability. That is, by subjecting the adhesive layer to a predetermined curing treatment, the cyclic ether groups in the cyclic ether compound (A) react to cure the adhesive layer to form a cured adhesive layer.
Examples of the curing treatment include heat treatment and light irradiation treatment. These can be appropriately determined according to the properties of the adhesive layer.

The storage elastic modulus of the cured adhesive layer at 90° C. is preferably 1×10 ⁸ Pa or more, more preferably 1×10 ⁹ to 1×10 ¹¹ Pa. A cured adhesive layer having a storage elastic modulus of 1×10 ⁸ Pa or more at 90° C. has excellent sealing properties and is therefore more suitable as a sealing material. In addition, after the formation of the cured adhesive layer, it becomes easier to prevent the cured adhesive layer from being broken or peeled off in the process for manufacturing the device sealing body.

The storage elastic modulus of the cured adhesive layer can be measured using a known dynamic viscoelasticity measuring device.
Specifically, it can be measured by the method described in Examples.

The cured adhesive layer has excellent adhesive strength. The adhesive strength of the cured adhesive layer is usually 1 to 20 N/25 mm, preferably 2.5 to 15 N/25 mm when subjected to a 180° peel test at a temperature of 23° C. and a relative humidity of 50%. . This 180° peel test can be performed, for example, under the conditions of a temperature of 23° C. and a relative humidity of 50% according to the adhesive force measurement method described in JIS Z0237:2009.

When the adhesive sheet for device sealing of the present invention is used for sealing a display or the like, the cured adhesive layer preferably has excellent colorless transparency. The total light transmittance of the cured adhesive layer having a thickness of 20 μm is preferably 85% or more, more preferably 90% or more. Although there is no particular upper limit for the total light transmittance, it is usually 95% or less.
The total light transmittance can be measured according to JIS K7361-1:1997.

The water vapor transmission rate of the cured adhesive layer is usually 0.1 to 200 g·m ^-2 ·day ^-1 , preferably 1 to 150 g·m ^-2 ·day ^-1 .
The water vapor transmission rate can be measured using a known gas transmission rate measuring device.

[Release film]
The device sealing adhesive sheet of the present invention has a first release film and a second release film.
When using the device-sealing adhesive sheet of the present invention, the release film is usually removed by peeling. At this time, since the second release film has a lower release force, the second release film is peeled and removed before the first release film.
In the following description, the "first release film" and the "second release film" are sometimes simply referred to as "the release film" without distinguishing between them.

The release film functions as a support in the manufacturing process of the device-sealing adhesive sheet, and also functions as a protective sheet for the adhesive layer until the device-sealing adhesive sheet is used.

As the release film, a conventionally known one can be used. Examples thereof include those having a release layer on a release film substrate. The release layer can be formed using a known release agent.

Examples of substrates for release films include paper substrates such as glassine paper, coated paper, and fine paper; 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, polypropylene resin, polyethylene resin; and the like.
Examples of release agents 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, fluorine-based resins, and the like.
The thickness of the release film is not particularly limited, but is usually about 20 to 250 μm.

[Adhesive sheet for device encapsulation]
The device sealing adhesive sheet of the present invention comprises the first release film, the second release film, and the adhesive layer sandwiched between the release films.
The adhesive sheet for device sealing of the present invention may have a three-layer structure of first release film/adhesive layer/second release film.

The method for producing the device sealing adhesive sheet of the present invention is not particularly limited. For example, a casting method can be used to produce the device-sealing adhesive sheet.

When manufacturing the device-sealing adhesive sheet by a casting method, it can be manufactured, for example, by the following method.
A coating solution containing two release films (release film (A) and release film (B)) having a release layer and components constituting an adhesive layer is prepared. A coating solution is applied to the release layer surface of the release film (A) using a known method, and the obtained coating film is dried to form an adhesive layer. Then, the release film (B) is overlaid on the adhesive layer so that the release layer surface of the release film (B) is in contact with the adhesive layer, whereby an adhesive sheet for device sealing can be obtained.

When preparing the coating liquid by diluting the components constituting the adhesive layer, solvents used for preparing the coating liquid include aromatic hydrocarbon solvents such as benzene and toluene; esters such as ethyl acetate and butyl acetate. ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as n-pentane, n-hexane and n-heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclohexane system solvent; and the like.
These solvents can be used singly or in combination of two or more.
The content of the solvent can be appropriately determined in consideration of coatability and the like.

Examples of methods for applying the coating liquid include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.

Methods for volatilizing the solvent in the coating film and drying the coating film include conventionally known drying methods such as hot air drying, hot roll drying and infrared irradiation.
The conditions for drying the coating film are, for example, 80 to 150° C. for 30 seconds to 5 minutes, more preferably 90 to 120° C. for 1 to 4 minutes. By drying the coating film at 90° C. or higher, the coating film can be easily dried even in a drying time of 5 minutes or less, resulting in excellent productivity.

The device sealing adhesive sheet of the present invention satisfies the following formula (1).

In the formula, x is the peeling force between the first peeling film and the adhesive layer (hereinafter sometimes referred to as "first peeling force". The unit is "mN/50 mm"), and y is the peeling force between the second peeling film and the adhesive layer (hereinafter sometimes referred to as "second peeling force". The unit is "mN/50 mm").

When the xy value is 20 or more, the release film can be peeled off without tearing the adhesive layer. The xy value is preferably 25-500, more preferably 30-300.

The first peel force is usually 30-200 mN/50 mm, preferably 40-150 mN/50 mm. If the first peel force is in such a range, after peeling off the second peeling film and bonding the adhesive layer to the adherend, when peeling off the first peeling film, the adhesive layer is removed from the adherend. The first release film can be easily removed without causing peeling.
The second peel force is usually 5 to 50 mN/50 mm, preferably 10 mN/50 mm or more and less than 30 mN/50 mm.
The first peel strength and the second peel strength can each be measured according to the method described in Examples.

The adhesive sheet for device encapsulation that satisfies the formula (1) and the adhesive sheet for device encapsulation in which each of the first peel force and the second peel force are within the above ranges can be obtained, for example, based on the following tendencies: Efficient production can be achieved by appropriately selecting a sheet of release film.

In general, the thicker the release film, the higher the release force tends to be.
In the above-described method for manufacturing an adhesive sheet for device encapsulation, the peel force between the release film (A) on which the coating solution is applied and the adhesive layer is determined by the release film ( Compared to the peel force between B) and the adhesive layer, the peel force tends to be higher even if the same release film is used. Therefore, in such a manufacturing method, it is preferable to use the first release film as the release film (A) in order to increase the difference between the first release force and the second release force.
In addition, when the release film (B) is heated when being superimposed on the adhesive layer, the release force between the release film (B) and the adhesive layer tends to be higher than when working at room temperature. Therefore, when the second release film is used as the release film (B), the release film (B) and the adhesive layer are stacked at room temperature in order to increase the difference between the first release force and the second release force. is preferred.

When a release film having a release layer formed from a silicone-based resin is selected as the two release films, there is the following tendency. Typical silicone resins include, for example, a first organopolysiloxane having at least two alkenyl groups (for example, vinyl groups) per molecule and a second organopolysiloxane having at least two hydrosilyl groups per molecule. of organopolysiloxane (corresponding to a cross-linking agent). In this case, the rigidity of the skeleton of the addition-reactive silicone resin affects the hardness of the release agent layer and the release force of the release film. Moreover, when a silicone resin is added to the addition reaction type silicone resin, the surface polarity can be adjusted and the release force can be adjusted by adjusting the blending amount of the silicone resin.

A method for producing a device sealing body using the device sealing adhesive sheet of the present invention is not particularly limited. For example, by performing the following steps (a1) to (a5) and steps (b1) to (b5), an object (device) to be sealed can be sealed and a device sealed body can be manufactured.

Step (a1): Peel off the second release film of the adhesive sheet for device sealing.
Step (a2): The adhesive layer exposed by performing step (a1) is attached to an object (device) to be sealed.
Step (a3): The first release film is peeled off from the material obtained in step (a2).
Step (a4): The adhesive layer exposed by performing step (a3) is attached to a substrate (glass plate, gas barrier film, etc.).
Step (a5): The adhesive layer contained in the one obtained in step (a4) is cured by a predetermined means to form a cured adhesive layer.

Step (b1): Peel off the second release film of the adhesive sheet for device sealing.
Step (b2): The adhesive layer exposed by performing step (b1) is attached to a substrate (glass plate, gas barrier film, etc.).
Step (b3): Peel off the first release film from the material obtained in step (b2).
Step (b4): The adhesive layer exposed by performing step (b3) is adhered to an object (device) to be sealed.
Step (b5): The adhesive layer contained in the one obtained in step (b4) is cured by a predetermined means to form a cured adhesive layer.

In the method for producing the device sealing body described above, in the step (a2) or step (b2), the adhesive layer is attached to the object to be sealed or the substrate from the viewpoint of work convenience and productivity. Environmental conditions are preferred. Similarly, step (b4) is also preferably carried out at room temperature.

In the device sealing adhesive sheet of the present invention, the release film can be peeled off without tearing the adhesive layer.
Furthermore, the cured adhesive layer formed using the adhesive layer constituting the adhesive sheet for device encapsulation of the present invention is excellent in adhesive strength and water vapor barrier properties. Therefore, the device sealing adhesive sheet of the present invention is suitably used as a material for forming a sealing material in a device sealing body.

A device sealing body is not specifically limited. Examples of device encapsulants include organic EL devices such as organic EL displays and organic EL lighting; liquid crystal displays; electronic paper; solar cells such as inorganic solar cells and organic thin film solar cells; When the cured adhesive layer obtained from the adhesive layer constituting the adhesive sheet for device encapsulation of the present invention is transparent, the adhesive sheet for device encapsulation of the present invention can be used for organic EL displays, organic EL lighting and the like. organic EL devices; liquid crystal displays; and electronic paper.

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is by no means limited to the following examples.
Parts and % in each example are based on mass unless otherwise specified.

[Method for measuring storage elastic modulus]
(1) Storage Elastic Modulus of Adhesive Layer The adhesive layers of the adhesive sheets for device sealing obtained in Examples or Comparative Examples were laminated at 23° C. using a laminator to a thickness of 1 mm or more. Using the laminate as a measurement sample, its storage modulus was measured.
That is, the measurement sample was measured using a storage modulus measuring device (manufactured by Anton Paar, trade name: Physica MCR301) under the conditions of a frequency of 1 Hz, a strain of 1%, and a heating rate of 3°C/min. A storage modulus value of 23° C. was obtained.
(2) Storage Elastic Modulus of Cured Adhesive Layer The adhesive layers of the adhesive sheets for device sealing obtained in Examples or Comparative Examples were laminated at 23° C. using a laminator to a thickness of 200 μm or more. The resulting laminate was heated at 100° C. for 1 hour to obtain a cured product. Using this cured product as a measurement sample, its storage elastic modulus was measured.
That is, for this measurement sample, a storage modulus measuring device (manufactured by TA Instruments, trade name: DMAQ800) was used, and the frequency was 11 Hz, the amplitude was 5 μm, and the heating rate was 3° C./min. The storage modulus was measured in the temperature range of ~+90°C and a storage modulus value of +90°C was obtained.

[Measurement of peel strength of first release film and second release film]
The device sealing adhesive sheets produced in Examples and Comparative Examples were cut to obtain test pieces having a width of 50 mm and a length of 150 mm. This test piece was subjected to a 180° peel test at a peel speed of 300 mm/min under conditions of a temperature of 23°C and a relative humidity of 50%.
That is, the adhesive layer exposed by peeling off the second release film of the adhesive sheet for device sealing was placed on non-alkali glass under conditions of a temperature of 23° C. and a relative humidity of 50%, and pressed with a pressing roll. After that, the peeling force of the first peeling film was obtained by performing the above peeling test. In the tear evaluation of the adhesive layer when peeling the second peeling film below, for those with an evaluation of "B", when the second peeling film is peeled, the adhesive layer is partially attached to the second peeling film. Careful manual peeling was performed so as not to cause excessive transfer.
On the other hand, for the peel test of the second release film, the above test piece is obtained with a double-sided tape attached to the exposed surface of the first release film, and the test piece is attached to the alkali-free glass with the double-sided tape. Together, a laminate having a layer structure of "non-alkali glass/double-sided tape/first release film/adhesive layer/second release film" was obtained. After that, this laminate was subjected to a peeling test of the second peeling film in the same manner as the peeling force of the first peeling film, and the peeling force was obtained.

[Evaluation of tearing of the adhesive layer when the second release film is peeled off]
In the measurement of the peel strength of the second release film, the state of transfer to the adhesive layer on the second release film after the peel test was conducted was observed, and tearing of the adhesive layer was evaluated according to the following criteria.
A: No transfer of the adhesive layer to the second release film.
B: The adhesive layer was torn and partially transferred to the second release film.

[Evaluation of sticking suitability of the adhesive layer to the object to be sealed]
In the measurement of the peel strength of the first release film, before the peel test, the state of lifting of the adhesive layer from the alkali-free glass was observed. It was evaluated as B.

[Compounds and Release Films Used in Examples or Comparative Examples]
Cyclic ether compound (AL1): Hydrogenated bisphenol A glycidyl ether epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: YX8034, liquid at 25 ° C., epoxy equivalent: 270 g / eq)
Cyclic ether compound (AL2): Hydrogenated bisphenol A glycidyl ether epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: YX8000, liquid at 25 ° C., epoxy equivalent: 205 g / eq)
- Binder resin (B1): Phenoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: YX7200B35, glass transition temperature: 150°C)
Curing catalyst (C1): imidazole-based curing catalyst (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name: Curesol 2E4MZ)
Curing catalyst (C2): thermal cationic polymerization initiator (manufactured by Sanshin Chemical Co., Ltd., trade name: San-Aid SI-B3)
- Silane coupling agent (D1): 8-glycidoxyoctyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM4803)
・ Release film (E1): manufactured by Lintec Corporation, product name: SP-PET752150
・ Release film (E2): manufactured by Lintec Corporation, product name: SP-PET381130
・ Release film (E3): manufactured by Lintec Corporation, product name: SP-PET751130
・ Release film (E4): manufactured by Lintec Corporation, product name: SP-PET381031

[Example 1]
Binder resin (B1) 100 parts by mass, cyclic ether compound (AL1) 250 parts by mass, curing catalyst (C1) 2 parts by mass, silane coupling agent (D1) 0.2 parts by mass are dissolved in methyl ethyl ketone, and the coating liquid is prepared.
This coating solution is applied onto the release-treated surface of the release film (E1) (first release film), and the resulting coating film is dried at 100° C. for 2 minutes to form an adhesive layer having a thickness of 15 μm. bottom. The release-treated surface of the release film (E2) (second release film) was attached to the adhesive layer to obtain an adhesive sheet for device sealing.

[Example 2]
In Example 1, 130 parts by mass of the cyclic ether compound (AL2) was used in place of the cyclic ether compound (AL1), and 3.8 parts by mass of the curing catalyst (C2) was used in place of the curing catalyst (C1). A device encapsulating adhesive sheet was obtained in the same manner as in Example 1 except for the above.

[Comparative Example 1]
Except that in Example 1, 250 parts by mass of the cyclic ether compound (AL2) was used instead of the cyclic ether compound (AL1), and 2 parts by mass of the curing catalyst (C2) was used instead of the curing catalyst (C1). obtained an adhesive sheet for device encapsulation in the same manner as in Example 1.

[Comparative Example 2]
In Example 1, the release film (E3) (first release film) was used instead of the release film (E1), and the release film (E4) (second release film) was used instead of the release film (E2). A device-sealing adhesive sheet was obtained in the same manner as in Example 1, except that the adhesive sheet was used.

[Comparative Example 3]
Except that in Example 1, 100 parts by mass of the cyclic ether compound (AL2) was used instead of the cyclic ether compound (AL1), and 5 parts by mass of the curing catalyst (C2) was used instead of the curing catalyst (C1). obtained an adhesive sheet for device encapsulation in the same manner as in Example 1.

The compositions of the adhesive layers of the device encapsulation adhesive sheets of Examples 1 and 2 and Comparative Examples 1 and 3, and test results are shown below.

In the device sealing adhesive sheets of Examples 1 and 2, the second release film can be peeled off without tearing the adhesive layer. In addition, the adhesive layer of the device-sealing adhesive sheet has sufficient adhesive strength at room temperature and is excellent in sticking suitability.
On the other hand, in the device sealing adhesive sheet of Comparative Example 1, the storage elastic modulus of the adhesive layer at 23° C. was too low, so that the adhesive layer was torn when the second release film was peeled off.
Further, in the device sealing adhesive sheet of Comparative Example 2, since the difference in the peeling force between the two peeling films was small, the adhesive layer was torn when the second peeling film was peeled off.
In addition, since the adhesive sheet for device sealing of Comparative Example 3 has a large storage elastic modulus at 23° C. of the adhesive layer, the second release film can be peeled off even if the difference in peel strength between the two release films is small. The adhesive layer was not torn during the test. However, the adhesive layer does not have sufficient adhesive strength at room temperature and is inferior in sticking suitability.

Claims (10)

A device sealing adhesive sheet having a first release film and a second release film, and an adhesive layer sandwiched between the first release film and the second release film, wherein the following requirements (I) to requirements ( An adhesive sheet for device encapsulation that satisfies all of III).
Requirement (I): The adhesive layer is a layer containing one or more compounds having a cyclic ether group.
Requirement (II): The storage elastic modulus at 23° C. of the adhesive layer is 5.0×10 ⁵ Pa or more and 3.0×10 ⁷ Pa or less.
Requirement (III): The value of the peeling force between the first peeling film and the adhesive layer is represented by x (mN/50 mm), and the value of the peeling force between the second peeling film and the adhesive layer is When expressed as y (mN/50 mm), the device sealing adhesive sheet satisfies the following formula (1).

The device sealing adhesive sheet according to claim 1, wherein at least one compound having a cyclic ether group is a compound that is liquid at 25°C. 3. The adhesive sheet for device sealing according to claim 2, wherein the content of the compound having a cyclic ether group, which is liquid at 25[deg.] C., is 53% by mass or more relative to the entire adhesive layer. The device sealing adhesive sheet according to any one of claims 1 to 3, wherein the adhesive layer further contains a thermal cationic polymerization initiator. 5. The device sealing adhesive sheet according to claim 4, wherein at least one compound having a cyclic ether group is a compound having a glycidyl ether group. The device sealing adhesive sheet according to any one of claims 1 to 5, wherein the adhesive layer further contains a binder resin. The adhesive sheet for device encapsulation according to claim 6, wherein the binder resin has a glass transition temperature of 90°C or higher. 8. The device sealing adhesive sheet according to claim 1, wherein the layer obtained by curing the adhesive layer has a storage elastic modulus at 90° C. of 1×10 ⁸ Pa or more. The adhesive sheet for device sealing according to any one of claims 1 to 8, wherein the value x of the peeling force between the first peeling film and the adhesive layer is 30 to 200 mN/50 mm. The step of peeling the second release film from the device sealing adhesive sheet according to any one of claims 1 to 9, and attaching the exposed adhesive layer to the object or substrate to be sealed in a temperature environment of 20 to 30 ° C. A method of manufacturing a device encapsulant, comprising a step of attaching.