TW202111047A - Device sealing adhesive sheet - Google Patents

Abstract

The present invention provides a device sealing adhesive sheet that has a first release film, a second release film, and an adhesive layer that is held between the first release film and the second release film, said device sealing adhesive sheet satisfying a requirement (I) and a requirement (II). A device sealing adhesive sheet according to the present invention has an adhesive layer having a superior stickability at a normal temperature and release films and is superior in terms of the peelability of the release films. Requirement (I): the adhesive layer contains one or more types of compounds having a cyclic ether group. Requirement (II): the storage modulus of the adhesive layer at 23 DEG C is 9.5*105 to 3.0*107 Pa.

Description

Adhesive sheet for device sealing

The present invention relates to an adhesive sheet for device sealing, which includes an adhesive layer and a release film that have excellent adhesion at room temperature (meaning 23°C, the same below), and the release film has excellent release properties .

In recent years, organic EL elements have attracted attention as light-emitting elements that can emit high-intensity light by low-voltage direct current driving. However, the organic EL element has a problem that light-emitting characteristics such as light-emitting brightness, light-emitting efficiency, and light-emitting uniformity tend to decrease with the passage of time. Oxygen, moisture, etc. penetrate into the inside of the organic EL element to cause deterioration of the electrode and the organic layer, which is considered to be the cause of the above-mentioned problem of reduced light-emitting characteristics. Therefore, it has been proposed to use an adhesive layer or an adhesive layer with excellent water resistance to form a sealing material to solve this problem.

For example, in Patent Document 1, a sheet-like sealing material is described, which includes a specific epoxy resin, a specific alicyclic epoxy compound, a thermal cationic polymerization initiator, a photocationic polymerization initiator, and a specific Sensitizer. The sealing material formed using the sheet-like sealing material described in Patent Document 1 has low oxygen permeability and water permeability, and has good sealing performance. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 201895679

[The problem to be solved by the invention]

As described in Patent Document 1, a sheet-shaped sealing material utilizing the reactivity of a cyclic ether group is suitable for use as a forming material of the sealing material. However, some of such sheet-like sealing materials have poor adhesion at room temperature, and some require heating to soften the surface when they are attached to the sealed object. On the other hand, among the sheet-like sealing materials that have good adhesion at room temperature, some have poor workability at the time of adhesion. That is, when the sheet-shaped sealing material (hereinafter sometimes referred to as "adhesive layer") sandwiched between two release films is cut into a predetermined shape, the adhesive layer is deformed by cutting into the punching knife , There may be cases where the peeling film cannot be peeled off efficiently because the adhesive is attached to the unpeeled part (cut surface) on the end of the peeling film.

In view of the foregoing, the object of the present invention is to provide an adhesive sheet for device sealing, which includes an adhesive layer having excellent adhesion at room temperature and a release film, and the release film has excellent release properties. [Means used to solve the problem]

In order to solve the above problems, the present inventors conducted intensive studies on an adhesive sheet for sealing including two release films and an adhesive layer sandwiched between the release films, and the adhesive layer is a compound having a cyclic ether group. . turn out: (A) An adhesive layer with a storage modulus at 23°C below a predetermined value has excellent adhesion at room temperature, and (B) An adhesive sheet comprising an adhesive layer and a release film whose storage modulus at 23°C is greater than or equal to a predetermined value. The release film has excellent releasability, Furthermore, the present invention has been completed.

Therefore, according to the present invention, the following [1] to [10] adhesive sheets for device sealing are provided.

[1] An adhesive sheet for device sealing, comprising a first release film and a second release film, and an adhesive layer interposed between the first release film and the second release film, and an adhesive sheet for device sealing, It is characterized by satisfying the following condition (I) and condition (II), condition (I): the aforementioned adhesive layer is a layer comprising one or more compounds having cyclic ether groups, condition (II): the aforementioned adhesion The storage modulus of the agent layer at 23°C is 9.5×10 ⁵ Pa or more and 3.0×10 ⁷ Pa or less. [2] The adhesive sheet for device sealing according to [1], wherein at least one of the aforementioned compounds having a cyclic ether group is a compound that is liquid at 25°C. [3] The pressure-sensitive adhesive sheet for device sealing according to [2], wherein the content of the compound that is liquid at 25° C. and has a cyclic ether group is 53% by mass or more with respect to the entire pressure-sensitive adhesive layer. [4] The pressure-sensitive adhesive sheet for device sealing according to [3], wherein the content of the compound that is liquid at 25° C. and has a cyclic ether group is 65% by mass or less with respect to the entire pressure-sensitive adhesive layer. [5] The adhesive sheet for device sealing according to any one of [1] to [4], wherein the adhesive layer further includes a curing agent, and at least one type of the curing agent is a thermal cationic polymerization initiator. [6] The adhesive sheet for device sealing according to [5], wherein all of the hardeners are thermal cationic polymerization initiators. [7] The pressure-sensitive adhesive sheet for device sealing according to [5] or [6], wherein at least one of the compounds having a cyclic ether group is a compound having a glycidyl ether group. [8] The pressure-sensitive adhesive sheet for device sealing according to any one of [5] to [7], wherein at least one of the aforementioned compounds having a cyclic ether group is an alicyclic epoxy resin. [9] The adhesive sheet for device sealing according to any one of [1] to [8], wherein the adhesive layer includes an adhesive resin, and the glass transition temperature (Tg) of at least one type of the adhesive resin is Adhesive resin above 60℃. [10] The adhesive sheet for device sealing according to any one of [1] to [9], wherein the storage modulus at 90°C of the layer obtained by curing the adhesive layer is 1×10 ⁸ Pa or more . [11] The pressure-sensitive adhesive sheet for device sealing described in any one of [1] to [10] is used to form a sealing material in an optical-related device. [Effects of the invention]

According to the present invention, there is provided an adhesive sheet for device sealing, which includes an adhesive layer having excellent adhesiveness at room temperature and a release film, and the release film has excellent release properties.

The adhesive sheet for device sealing of the present invention is an adhesive sheet for device sealing including a first release film and a second release film, and an adhesive layer interposed between the first release film and the second release film, and is characterized by Meet the following condition (I) and condition (II).

In the present invention, the "first peeling film" refers to the peeling film that is peeled off after the "second peeling film" when the adhesive sheet for device sealing is used, and the "second peeling film" refers to the peeling film that is peeled off after the device sealing adhesive sheet is used. The peeling film that is peeled off first when the adhesive sheet is attached. Therefore, when two peeling films have different peeling forces, the "first peeling film" usually refers to the one with high peeling force among the two peeling films, and the "second peeling film" refers to the two peeling films. Those with low peel strength in the film. The so-called "adhesive layer" refers to a layer that coats a curable adhesive and has curability and adhesiveness. That is, the "adhesive layer" is a layer in an uncured state. In this specification, the "layer obtained by curing the adhesive layer" may be referred to as the "adhesive cured material layer". This hardened adhesive layer will be used as a sealing material. In the present invention, the so-called "hardening" means that the cyclic ether group contained in the adhesive layer reacts to increase the cohesive force and storage modulus of the layer.

[Adhesive layer] (Compounds with cyclic ether groups) The adhesive layer includes one or two or more compounds having a cyclic ether group (hereinafter sometimes referred to as "cyclic ether compound (A)"). By hardening the adhesive layer containing the cyclic ether compound (A), it is possible to form a sealing material with high adhesive strength and excellent moisture barrier properties.

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

The molecular weight of the cyclic ether compound (A) is usually 100 to 5,000, preferably 200 to 3,000. The cyclic ether equivalent of the cyclic ether compound (A) is preferably 50 to 1000 g/eq, and more preferably 100 to 800 g/eq. By hardening the adhesive layer including the cyclic ether compound (A) whose cyclic ether equivalent is within the above-mentioned range, it is possible to more efficiently form a sealing material with higher adhesive strength and better water resistance. In the present invention, the term "cyclic ether equivalent system" means a value obtained by dividing the molecular weight by the number of cyclic ether groups.

Examples of the cyclic ether group include an oxirane group (epoxy group), an oxetanyl group (Oxetanyl), a tetrahydrofuran group, and a tetrahydropyranyl group. Among them, from the viewpoint that a sealing material with higher adhesive strength can be formed, the cyclic ether group is preferably an oxirane group or an oxyalkyl group, and more preferably an oxirane group. Furthermore, for the same reason, the cyclic ether compound (A) preferably has two or more ethylene oxide groups or oxyalkyl groups in the molecule, and preferably has two or more ethylene oxide groups in the molecule. The base is better.

Examples of the compound having an oxirane group in the molecule include aliphatic epoxy compounds (excluding alicyclic epoxy compounds), aromatic epoxy compounds, and alicyclic epoxy compounds. Examples of the aliphatic epoxy compound include monofunctional epoxy compounds such as glycidyl etherate of aliphatic alcohol and glycidyl ester of alkyl carboxylic acid; Polyfunctional epoxy compounds such as polyglycidyl etherate of aliphatic polyols, or alkylene oxide adducts thereof, and polyglycidyl esters of aliphatic long-chain polybasic acids.

Typical compounds of these aliphatic epoxy compounds include alkenyl glycidyl ethers such as allyl glycidyl ether; butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and C12-13 mixed alkyl glycidyl ether Alkyl glycidyl ether such as glycerol ether; 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, triglycidyl ether of glycerol, triglycidyl ether of trimethylolpropane, sorbus The glycidyl ether of polyhydric alcohols such as tetraglycidyl ether of sugar alcohol, hexaglycidyl ether of dineopentaerythritol, diglycidyl ether of polyethylene glycol, and diglycidyl ether of polypropylene glycol; Polyglycidyl etherate of polyether polyol obtained by adding one or more alkylene oxides to aliphatic polyols such as methyl propane and glycerin; diglycidyl ester of aliphatic long-chain dibasic acid; Monoglycidyl ether of higher fatty alcohol, glycidyl ester of higher fatty acid, epoxidized soybean oil, epoxy octyl stearate, epoxy butyl stearate, epoxidized polybutadiene; etc.

Furthermore, a commercially available product can also be used as the aliphatic epoxy compound. Commercial 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 (the above are manufactured by Nagase Chemtex); 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 (the above are manufactured by Kyoeisha Chemical Co., Ltd.); ADEKA GLYCIROL ED-503, ADEKA GLYCIROL ED-503G, ADEKA GLYCIROL ED-506, ADEKA GLYCIROL ED-523T (the above are manufactured by ADEKA).

Examples of aromatic epoxy compounds include phenols having at least one aromatic ring such as phenol, cresol, and butyl phenol, or mono/polyglycidyl ether compounds of alkylene oxide adducts thereof; Heterocyclic epoxy compounds; etc. As a typical compound of these aromatic epoxy compounds, glycidyl etherate or epoxy novolak resin of bisphenol A, bisphenol F, or a compound to which alkylene oxide is further added; Mono/polyglycidyl etherate of aromatic compounds with more than 2 phenolic hydroxyl groups, such as resorcinol, hydroquinone, or catechol; Glycidyl ether compounds of aromatic compounds with more than two alcoholic hydroxyl groups, such as phenyldimethanol, phenyldiethanol, and phenyldibutanol; Glycidyl esters of polybasic acid aromatic compounds such as phthalic acid, terephthalic acid, and trimellitic acid having two or more carboxylic acids, glycidyl esters of benzoic acid, styrene oxide, or divinylbenzene Epoxy compound Epoxy compounds having a triazine skeleton such as 2,4,6-tris(glycidyloxy)-1,3,5-triazine; etc.

Furthermore, a commercially available product can also be used as the aromatic epoxy compound. Commercial 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, ONCOAT EX -1040, ONCOAT EX-1050, ONCOAT EX-1051, ONCOAT EX-1010, ONCOAT EX-1011, ONCOAT 1012 (the above are manufactured by Nagase Chemtex); OGSOL PG-100, OGSOL EG-200, OGSOL EG-210, OGSOL EG-250 (the above are manufactured by Osaka Gas Chemical Company); HP4032, HP4032D, HP4700 (the above are manufactured by DIC); ESN-475V (the above are manufactured by Nippon Steel Chemical & Material Co., Ltd.); JER YX8800 (the above are manufactured by Mitsubishi Chemical Corporation); Marproof G-0105SA, Marproof G-0130SP (the above are manufactured by NOF Corporation); Epiclon N-665, Epiclon HP-7200 (the above are manufactured by DIC); EOCN-1020, EOCN-102S, EOCN-103S, EOCN-104S, XD-1000, NC-3000, EPPN-501H, EPPN-501HY, EPPN-502H, NC-7000L (the above are manufactured by Nippon Kayaku Corporation); ADEKA resin EP-4000, ADEKA resin EP-4005, ADEKA resin EP-4100, ADEKA resin EP-4901 (the above are manufactured by ADEKA company); TECHMORE VG-3101L (the above are manufactured by Printec): TEPIC-FL, TEPIC-PAS, TEPIC-UC (the above are manufactured by Nissan Chemical Company); etc.

As the alicyclic epoxy compound, a polyglycidyl etherate of a polyol having at least one alicyclic structure, or a compound containing cyclohexene or cyclopentene ring is epoxidized with an oxidizing agent. Compounds containing cyclohexene oxide or cyclopentene oxide. As typical compounds of these alicyclic epoxy compounds, hydrogenated bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, 3, 4-epoxy-1-methylcyclohexyl-3,4-epoxy-1-methylhexane carboxylate, 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl- 3,4-epoxycyclohexane carboxylate, 3,4-epoxy-3-methylcyclohexylmethyl-3,4-epoxy-3-methylcyclohexane carboxylate, 3,4 -Epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl)adipate, 3 ,4-Epoxy-6-methylcyclohexane carboxylate, methylene bis(3,4-epoxycyclohexane), propane-2,2-diyl-bis(3,4-epoxy Cyclohexane), 2,2-bis(3,4-epoxycyclohexyl) propane, dicyclopentadiene diepoxide, dicyclopentadiene diepoxide, dicyclopentadiene diglycidyl ether, ethylene bis (3,4-epoxycyclohexane carboxylate), dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1-epoxyethyl -3,4-epoxycyclohexane, 1,2-epoxy-2-epoxyethylcyclohexane, α-pinene oxide, limonene dioxide, etc.

Furthermore, a commercially available product can also be used as the alicyclic epoxy compound. Commercial products include CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2000, CELLOXIDE 3000 (manufactured by Daicel); Epilite 4000 (manufactured by Kyoeisha Chemical Co.); jER YX8000, jER YX8034 (manufactured by Mitsubishi Chemical company); ADEKA resin EP-4088S, ADEKA resin EP-4088L, ADEKA resin EP-4080E (the above are manufactured by ADEKA company); etc.

In addition, examples of the compound having an oxirane group in the molecule include epoxy compounds having both an alicyclic structure and an aromatic ring in one molecule. As such a compound, for example, Epiclon HP-7200 (manufactured by DIC Corporation) can be cited.

Among them, from the viewpoint of reducing the dielectric constant of the adhesive cured layer and the ease of forming a colorless and transparent adhesive cured layer, as the compound having an oxirane group, an alicyclic epoxy resin Better. Furthermore, in the case where the adhesive layer includes a cationic polymerization initiator, an alicyclic epoxy resin is preferred from the viewpoint of high reactivity of cationic polymerization to prevent the cationic polymerization from proceeding too slowly. Furthermore, in the case of using a thermal cationic polymerization initiator as the hardener described later, the compound having an oxirane group is preferably a compound having a glycidyl ether group. The cationic polymerization reaction involving the glycidyl ether group tends to proceed relatively smoothly. Therefore, when there is a step of heating the composition including the components constituting the adhesive layer (for example, the step of heating to 90°C or higher) during the manufacturing process of the adhesive layer, the polymerization reaction of the glycidyl ether group It is difficult to carry out, and it is easy to maintain the low storage modulus of the adhesive layer at 23°C. The content of the compound having a glycidyl ether group is preferably 70% by mass or more, and more preferably 90% by mass or more with respect to the entire compound having a cyclic ether group. Furthermore, when the content of the compound having a glycidyl ether group is 90% by mass or more with respect to the entire compound having a cyclic ether group, the storage stability of the adhesive layer can be improved.

As the compound having an oxo group in the molecule, 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, triethyl Glycol bis(3-ethyl-3-oxetanyl methyl) ether, tetraethylene glycol bis(3-ethyl-3-oxetanyl methyl) ether, 1,4- Bis(3-ethyl-3-oxetanylmethoxy)butane, 1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, etc. Functional aliphatic oxygen compound, 3-ethyl-3-[(phenoxy)methyl]oxygen, 3-ethyl-3-(hexyloxymethyl)oxygen, 3-ethyl-3- Monofunctional oxygen compounds such as (2-ethylhexyloxymethyl) oxygen, 3-ethyl-3-(hydroxymethyl) oxygen, 3-ethyl-3-(chloromethyl) oxygen, etc. Wait.

A commercially available product can also be used as a compound having an oxygen group in the molecule. Commercial products include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether (manufactured by Maruzen Petrochemical Company); ARONE OXETANE OXT-121, OXT-221, EXOH, POX, OXA, OXT-101, OXT-211, OXT-212 (the above are manufactured by Toagosei Corporation); Eternacoll OXBP, OXTP (the above are manufactured by Ube Industries Co., Ltd.), etc.

The above-mentioned cyclic ether compound (A) may be used individually by 1 type, or may be used in combination of 2 or more types.

The content of the cyclic ether compound (A) in the adhesive layer (the total amount when two or more cyclic ether compounds (A) are included) relative to the entire adhesive layer is preferably 53 to 80% by mass, And it is preferably 57 to 75% by mass. By making the content of the cyclic ether compound (A) within the above range, it becomes easy to obtain a cured adhesive layer with a high storage modulus at 90°C.

At least one kind of the cyclic ether compound (A) in the adhesive layer is preferably a compound (cyclic ether compound (AL)) that is liquid at 25°C. Here, one of the aggregation states of the liquid-based substance means a state that has a substantially fixed volume but does not have a specific shape. The cyclic ether compound (AL) preferably has a viscosity of 2 to 10,000 mPa·s measured at 25° C. and 1.0 rpm using an E-type viscometer. By using the cyclic ether compound (AL), 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 the adhesive agent layer which has sufficient adhesive force at normal temperature and is excellent in adhesiveness.

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) is preferably 150 to 1000 g/eq, and more preferably 240 to 900 g/eq.

Relative to the entire adhesive layer, the content of the cyclic ether compound (AL) in the adhesive layer (when two or more compounds are included, the total amount) is preferably 53% by mass or more, and 57% by mass or more Better. By making the content of the cyclic ether compound (AL) 53% by mass or more with respect to the entire adhesive layer, it becomes easy to obtain an adhesive layer having sufficient adhesive force at room temperature and excellent adhesion. It is also easy to obtain a cured adhesive layer with a high storage modulus at 90°C.

For the entire adhesive layer, the content of the cyclic ether compound (AL) in the adhesive layer (the total amount when two or more compounds are included) is preferably 70% by mass or less, and 68% by mass or less is more preferable good. By making the content of the cyclic ether compound (AL) 70% by mass or less with respect to the entire adhesive layer, it becomes easy to obtain an adhesive sheet for device sealing having excellent peelability of the peeling film.

(Binder resin) The adhesive layer may also include adhesive resin (B). The shape retention and handleability of the adhesive layer including the adhesive resin (B) become excellent.

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

When the adhesive layer includes the adhesive resin (B), relative to the entire adhesive layer, the content of the adhesive resin (B) (when two or more types of adhesive resins (B) are included, the total amount) is 20~ 46% by mass is preferable, and 23-44% by mass is more preferable. When the content of the binder resin (B) is within the above range, it becomes easy to obtain an adhesive layer having excellent shape retention and sufficient adhesive force.

As the binder resin (B), a resin having a glass transition temperature (Tg) of 60°C or higher is preferable, a resin having a glass transition temperature (Tg) of 90°C or higher is preferable, and a resin having a glass transition temperature (Tg) of 110°C or higher is more preferable. By using a resin with a glass transition temperature (Tg) of 60°C or higher, it becomes easy to set the storage modulus of the cured adhesive layer at 90°C to 1×10 ⁸ Pa or higher. Furthermore, since the glass transition temperature (Tg) of the adhesive resin (B) is 90°C or higher, even when a large amount of cyclic ether compound (AL) is included, the adhesive layer is easily kept at 23°C. The storage modulus of is set to be within the range ^{of 9.5×10 5 Pa or more described later.} The glass transition temperature (Tg) of the binder resin (B) can be measured using a differential scanning calorimeter in accordance with JIS K7121.

Examples of the binder resin (B) include phenoxy resins, polyimide resins, polyimide resins, polyvinyl butyral resins, polycarbonate resins, acrylic resins, and polyurethanes. Type resin, modified olefin type resin, etc. The above-mentioned resins may be used singly or in combination of two or more kinds.

As the binder resin (B), at least one selected from the group consisting of phenoxy resins and modified olefin resins is preferred, and the storage modulus of the cured adhesive layer at 90°C is improved. From the viewpoint of phenoxy resins, phenoxy resins are preferred.

The phenoxy resin generally corresponds to a high molecular weight epoxy resin, and means a resin having a degree of polymerization of about 100 or more.

The weight average molecular weight (Mw) of the phenoxy resin is preferably 10,000 to 150,000, and more preferably 10,000 to 100,000. Gel permeation chromatography (GPC) can be performed using tetrahydrofuran (THF) as a solvent, and the measured value in terms of standard polystyrene is the weight average molecular weight (Mw) of the phenoxy resin. The phenoxy resin corresponding to this high molecular weight epoxy resin has excellent heat distortion resistance. The epoxy equivalent of the phenoxy resin is preferably 5,000 or more, and more preferably 7,000 or more. The epoxy equivalent value of the phenoxy resin can be measured in accordance with JIS K7236.

Examples of phenoxy resins include bisphenol A type, bisphenol F type, bisphenol S type phenoxy resin, copolymer type phenoxy resin of bisphenol A type and bisphenol F type, and distillates thereof , Naphthalene type phenoxy resin, novolak type phenoxy resin, biphenyl type phenoxy resin, cyclopentadiene type phenoxy resin, etc. These phenoxy resins may be used individually by 1 type, or may be used in combination of 2 or more types.

The phenoxy resin can be obtained by the method of reacting bifunctional phenols and epihalohydrin to a high molecular weight, or by the addition polymerization reaction of bifunctional epoxy resin and bifunctional phenol. For example, it can be obtained by reacting bifunctional phenols and epihalohydrin at a temperature of 40 to 120°C in an inert solvent in the presence of an alkali metal hydroxide. Furthermore, in the presence of catalysts such as alkali metal compounds, organophosphorus compounds, cyclic amine compounds, etc., the boiling point of amine solvents, ether solvents, ketone solvents, lactone solvents, alcohol solvents, etc. It is obtained by heating a bifunctional epoxy resin and a bifunctional phenol to a reaction solid content concentration of 50% by weight or less in an organic solvent of 120°C or higher to 50 to 200°C to perform an addition polymerization reaction.

The 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, bisphenol A, bisphenol F, bisphenol AD, bisphenol Bisphenols such as S, dihydroxybiphenyls such as 4,4'-dihydroxybiphenyl, dihydroxyphenyl ethers such as bis(4-hydroxyphenyl) ether; Compounds such as linear alkyl groups, branched chain alkyl groups, aromatic groups, hydroxymethyl groups, allyl groups, cyclic aliphatic groups, halogens (tetrabromobisphenol A, etc.), and nitro groups are introduced into the ring; Polycyclic bifunctional phenols with linear alkyl groups, branched chain alkyl groups, allyl groups, substituted allyl groups, cyclic aliphatic groups, and alkoxycarbonyl groups introduced into the central carbon atom of the phenol skeleton; etc. .

Examples of epihalohydrins include epichlorohydrin, epibromohydrin, epiiodohydrin, and the like.

Furthermore, in the present invention, a commercially available product can also be used as the phenoxy resin. For example, the product names made by Mitsubishi Chemical Corporation: YX7200 (glass transition temperature: 150°C), YX6954 (phenoxy resin containing bisphenol acetophenone skeleton, glass transition temperature: 130°C), YL7553, YL6794, YL7213, YL7290, YL7482, YX8100 (phenoxy resin containing bisphenol S skeleton), product names manufactured by Toto Kasei: FX280, FX293, FX293S (phenoxy resin containing fluorene skeleton), products manufactured by Mitsubishi Chemical Corporation Name: jER1256, jER4250 (glass transition temperature: less than 85°C), jER4275 (glass transition temperature: 75°C), product name manufactured by Nippon Steel Chemical Materials Co., Ltd.: YP-50 (glass transition temperature: 84°C), YP -50S (any of them are phenoxy resins containing bisphenol A skeleton), YP-70 (bisphenol A skeleton/bisphenol F skeleton copolymerized phenoxy resin, glass transition temperature: less than 85°C), ZX-1356-2 (Glass transition temperature: 72℃) etc. In addition, the glass transition temperature has been listed for materials for which the glass transition temperature is known.

The modified olefin resin system uses a modifier to apply a modification treatment to an olefin resin as a precursor to obtain an olefin resin into which a functional group is introduced.

The so-called olefin-based resin refers to a polymer including repeating units derived from olefin-based monomers. The olefin resin may be a polymer composed only of repeating units derived from olefin monomers, or it may be a polymer composed of repeating units derived from olefin monomers and monomers copolymerizable with olefin monomers. The constituted polymer.

As the olefin monomer, an α-olefin having 2 to 8 carbon atoms is preferred, ethylene, propylene, 1-butene, isobutylene, or 1-hexene is preferred, and ethylene or propylene is more preferred . The above-mentioned olefin-based monomers may be used singly or in combination of two or more kinds. Examples of monomers that can be copolymerized with olefin-based monomers include vinyl acetate, (meth)acrylate, styrene, and the like. Here, "(meth)acrylic acid" means acrylic acid or methacrylic acid (the same applies hereinafter). The above-mentioned monomers copolymerizable with the olefin-based monomer may be used alone or in combination of two or more kinds.

Examples of olefin resins include ultra-low-density polyethylene (VLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene, poly Propylene (PP), ethylene-propylene copolymer, olefin elastomer (TPO), ethylene-vinyl acetate copolymer (EVA), ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer Wait.

The modifier used for the modification treatment of the olefin resin is a compound having a functional group in the molecule. Examples of functional groups include carboxyl groups, carboxylic acid anhydride groups, carboxylate groups, hydroxyl groups, epoxy groups, amide groups, ammonium groups, nitrile groups, amino groups, amide groups, isocyanate groups, acetyl groups, and sulfur groups. Alcohol groups, ether groups, thioether groups, sulfide groups, phosphine groups, nitro groups, urethane groups, alkoxysilyl groups, silanol groups, halogen atoms, etc. The compound having a functional group may have two or more types of functional groups in the molecule.

The weight average molecular weight (Mw) of the modified olefin resin is preferably 10,000 to 150,000, and more preferably 30,000 to 100,000. Gel permeation chromatography (GPC) can be performed using tetrahydrofuran (THF) as a solvent, and the measured value in terms of standard polystyrene is the weight average molecular weight (Mw) of the modified olefin resin.

As the modified olefin resin, an acid modified olefin resin is preferred. The acid-modified olefin-based resin refers to a resin obtained by graft-modifying an olefin-based resin with an acid or an acid anhydride. For example, it can be obtained by reacting olefin resin with unsaturated carboxylic acid or unsaturated carboxylic anhydride (hereinafter sometimes referred to as "unsaturated carboxylic acid, etc.") to introduce carboxyl group or carboxylic anhydride group (graft modification) Of resin.

Examples of unsaturated carboxylic acids that react with olefin resins 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, glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride and other unsaturated carboxylic acid anhydrides; etc. These may be used individually by 1 type, or may be used in combination of 2 or more types. Among them, since a sealing material with higher adhesive strength can be easily obtained, maleic anhydride is preferred.

With respect to 100 parts by mass of olefin resin, the content of unsaturated carboxylic acid etc. which can react with olefin resin is preferably 0.1-5 parts by mass, preferably 0.2-3 parts by mass, and 0.2-1 parts by mass Better. The resulting adhesive layer including the acid-modified olefin resin is hardened, and a sealing material with higher adhesive strength can be formed.

The method of introducing the unsaturated carboxylic acid unit or the unsaturated carboxylic anhydride unit into the olefin-based resin is not particularly limited. For example, a method of heating an olefin resin and an unsaturated carboxylic acid above the melting point of the olefin resin in the presence of a radical generator such as an organic peroxide or nitrile , Or after dissolving the olefin resin and the unsaturated carboxylic acid in an organic solvent, heating and stirring in the presence of a radical generator to react, etc., the olefin resin and the unsaturated carboxylic acid And other methods of graft copolymerization.

Commercial products can also be used as acid-modified olefin resins. Examples of commercially available products include Admer (registered trademark) (manufactured by Mitsui Chemicals), Unistole (registered trademark) (manufactured by Mitsui Chemicals), BondyRam (manufactured by Polyram), Orevac (registered trademark) ) (Manufactured by ARKEMA), Modic (registered trademark) (manufactured by Mitsubishi Chemical Corporation), etc.

[hardener] The adhesive layer may also include a hardener. The adhesive layer includes a hardener, which can further improve the hardenability of the adhesive layer. The curing agent is not particularly limited as long as it can initiate a curing reaction, but from the viewpoint that there may be situations in which the step of curing the adhesive layer with ultraviolet rays or other energy rays is difficult or should be avoided, or the introduction of energy rays is never necessary. From the viewpoint of the device, it is preferable to use a hardening agent that can initiate a hardening reaction by heating. Examples of the hardener include thermal cationic polymerization initiators and other hardeners. Examples of hardeners other than the thermal cationic polymerization initiator include tertiary amines such as benzylmethylamine, 2,4,6-dimethylaminomethylphenol; 2-methylimidazole, 2- Imidazole compounds such as ethyl-4-methylimidazole and 2-heptadecylimidazole; Lewis acids such as boron trifluoride/monoethylamine complexes and boron trifluoride/piperazine complexes; etc.

The curing agent may be used singly or in combination of two or more kinds. When the adhesive layer includes a hardener, the content of the hardener is not particularly limited, but with respect to 100 parts by mass of the cyclic ether compound (A), it is preferably 0.1-15 parts by mass, and 1-10 parts by mass is more preferred. Better, and more preferably 1 to 5 parts by mass.

The adhesive layer is preferably at least one type including a thermal cationic polymerization initiator as a hardener. By using a thermal cationic polymerization initiator, the curability of the adhesive layer can be precisely controlled.

The thermal cationic polymerization initiator is a compound capable of generating cationic species that initiate polymerization by heating. Examples of the thermal cationic polymerization initiator include sulfonium (Sulfonium) salt, quaternary ammonium salt, phosphonium salt, diazonium (Diazonium) salt, and iodonium (iodonium) salt.

Examples of the sulfonate include triphenyl tetrafluoroborate, triphenyl hexafluoroantimonate, triphenyl hexafluoroarsenate (triphenylsulphonium hexafluoroarsenate), and ginseng (4-methoxyphenyl). Hexafluoroarsenate, diphenyl(4-phenylthiophenyl) hexafluoroarsenate, (4-acetoxyphenyl)methyl(2-methylbenzyl)4(pentafluoro Phenyl) borate sulfonate, (4-hydroxyphenyl) methyl (4-methylbenzyl) tetra (pentafluorophenyl) borate sulfonate, (4-acetoxyphenyl) benzyl (methyl ) Four (pentafluorophenyl) borate sulfonium salt, benzyl (4-hydroxyphenyl) (methyl) four (pentafluorophenyl) borate sulfonate, etc.

It is also possible to use a commercially available product as the aqua salt. Commercially available products include Adeka Opton SP-150, Adeka Opton SP-170, Adeka Opton CP-66, Adeka Opton CP-77 (manufactured by Asahi Denka), Sunaid SI-60L, Sunaid SI-80L , Sunaid SI-100L, Sunaid SI-B2A, Sunaid SI-B7, Sunaid SI-B3A, Sunaid SI-B3 (manufactured by Sanxin Chemical Company), CYRACURE UVI-6974, CYRACURE UVI-6990 (by Union Carbide (Manufactured by Union Carbide), UVI-508, UVI-509 (manufactured by GE/General Electric), FC-508, FC-509 (the above are manufactured by Minnesota Mining and Manufacturing, 3M), CD-1010, CD-1011 (manufactured by Sartomer Company above), CI series products (manufactured by Japan Soda Company above), etc.

Examples of quaternary ammonium salts include tetrabutylammonium tetrafluoroborate, tetrabutylammonium hexafluorophosphate, tetrabutyl ammonium hydrogen sulfate, tetraethylammonium tetrafluoroborate, and tetraethylammonium p-toluenesulfonate. , N,N-dimethyl-N-benzylanilinium hexafluoroantimonate (N,N-dimethyl-N-benzylanilinium hexafluoroantimonate), N,N-dimethyl-N-benzylanilinium hexafluoroantimonate, N,N-dimethyl-N-benzylanilinium hexafluoroantimonate, N,N-dimethyl-N-benzylpyridinium hexafluoroantimonate (N,N-dimethyl-N-benzylpyridinium hexafluoroantimonate), N,N-diethyl-N-benzyl trifluoromethanesulfonate , N,N-dimethyl-N-(4-methoxybenzyl) pyridinium hexafluoroantimonate (N,N-dimethyl-N-(4-methoxybenzyl) pyridinium hexafluoroantimonate), N,N-two Ethyl-N-(4-methoxybenzyl) toluidinium hexafluoroantimonate (N,N-diethyl-N-(4-methoxybenzyl) toluidinium hexafluoroantimonate) etc.

Examples of the phosphonium salt include ethyltriphenylphosphonium hexafluoroantimonate, tetrabutylphosphonium hexafluoroantimonate, and the like.

As the diazonium salt, AMERICURE (manufactured by American Can Corporation), ULTRASET (manufactured by Asahi Denka Co., Ltd.), and the like can be cited.

Examples of iodonium salts include diphenyliodonium hexafluoroarsenate, bis(4-chlorophenyl)iodonium hexafluoroarsenate, and bis(4-bromophenyl)iodonium hexafluoroarsenate. , Phenyl (4-methoxyphenyl) iodonium hexafluoroarsenate, etc. Furthermore, as commercially available products, UV-9310C (manufactured by Toshiba Silicone), Photoinitiator 2074 (manufactured by Rhone-Poulenc), and UVE series products (manufactured by Qiwei /General Electric Company), FC series products (manufactured by Minnesota Mining and Manufacturing (3M) Company), etc.

The thermal cationic polymerization initiator may be used singly or in combination of two or more kinds.

In the adhesive sheet for device sealing of the present invention, it is preferable that all the hardeners contained in the adhesive layer are thermal cationic polymerization initiators. If a hardener other than the thermal cationic polymerization initiator is used, the adhesive layer may be colored or the transparency of the adhesive layer may decrease. On the other hand, when a thermal cationic polymerization initiator is used, the above-mentioned problems are unlikely to occur. Therefore, all the hardeners contained in the adhesive layer are thermal cationic polymerization initiators, which can efficiently form colorless Adhesive layer with excellent transparency.

(Silane coupling agent) The adhesive layer may also include a silane coupling agent. By hardening the adhesive layer including the silane coupling agent, it is possible to form a sealing material with more excellent wet-heat durability.

As the silane coupling agent, a known silane coupling agent can be used. Among them, an organosilicon compound having at least one alkoxysilyl group in the molecule is preferred.

As the silane coupling agent, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyl 2-methyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane Silane coupling agents with (meth)acrylic acid groups, such as silyl silanes; Vinyl trimethoxy silane, vinyl triethoxy silane, dimethoxy methyl vinyl silane, diethoxy methyl vinyl silane, trichloro vinyl silane, vinyl ginseng (2-methoxy Ethoxy) silane, 7-octenyl trimethoxysilane and other silane coupling agents with vinyl groups; 2-(3,4-epoxycyclohexyl) ethyl trimethoxy silane, 3-glycidoxy propyl trimethoxy silane, 3-glycidoxy propyl methyl diethoxy silane, Silicone coupling agents with epoxy groups such as 3-glycidoxypropyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, etc.; Silane coupling agents with styryl groups such as p-styryltrimethoxysilane and p-styryltrimethoxysilane;

N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-( 2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilane -N-(1,3-dimethylbutylidene) propylamine (3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine), N-phenyl-3-aminopropyl trimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl trimethoxysilane hydrochloride, N-(2-aminoethyl)-8-aminooctyl trimethoxy Silane coupling agents with amine groups, such as silane coupling agents; Silane coupling agents with ureido groups such as 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane; Silane coupling agents with halogen atoms such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane; Silane coupling agents with mercapto groups such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; Silane coupling agents with sulfide groups such as bis(triethoxysilylpropyl) tetrasulfide and bis(triethoxysilylpropyl) tetrasulfide; Silane coupling agents with isocyanate groups such as 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc.; Allyl trichlorosilane, allyl triethoxy silane, allyl trimethoxy silane and other silane coupling agents with allyl groups; Silane coupling agents with hydroxyl groups such as 3-hydroxypropyltrimethoxysilane and 3-hydroxypropyltriethoxysilane; etc. Among them, from the viewpoint of improving the adhesiveness of the adhesive layer to the adherend, it is preferable to use a long-chain spacer type silane coupling agent having a linear alkyl group having 6 or more carbon atoms. Examples of the long-chain spacer type silane coupling agent having a linear alkyl group with 6 or more carbon atoms include 8-methacryloxy octyl trimethoxy silane and 7-octenyl trimethoxy silane Silane, 8-glycidoxy octyl trimethoxy silane, N-(2-aminoethyl)-8-amino octyl trimethoxy silane, etc., and 8-glycidoxy octyl Trimethoxysilane is preferred. The above-mentioned silane coupling agent may be used singly or in combination of two or more kinds.

When the adhesive layer includes a silane coupling agent, relative to the entire adhesive layer, the content of the silane coupling agent is preferably 0.01-5 mass%, and more preferably 0.05-1 mass%.

[Other ingredients] The adhesive layer may include other components within a range that does not hinder the effects of the present invention. Examples of other components include additives such as ultraviolet absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, pigments, extenders, softeners, and tackifiers. These components may be used individually by 1 type, or may be used in combination of 2 or more types. In the case where the adhesive layer includes the above-mentioned additives, the content can be appropriately determined according to the purpose.

(Adhesive layer) The shape, size, etc. of the adhesive layer are not particularly limited. The adhesive layer may be rectangular or elongated. In this specification, the "long strip" refers to a shape with a length of 5 times or more the width, and preferably a length of 10 times or more the width. Specifically, it means a shape sufficient to be wound into a roll. The shape of the film for the length of storage or transportation. The upper limit of the ratio of the length to the width of the film is not particularly limited, and may be, for example, 100,000 times or less.

The thickness of the adhesive layer is usually 1-50 μm, preferably 1-25 μm, and preferably 5-25 μm. The adhesive layer having a thickness within the above-mentioned range is suitable as a forming material of the sealing material. The thickness of the adhesive layer can be measured using a known thickness gauge in accordance with JIS K 7130 (1999).

The adhesive layer may have a single-layer structure or a multi-layer structure (composed of multiple layers of adhesives). The adhesive layer may have a uniform composition or a non-uniform composition (for example, in the adhesive layer with the above-mentioned multilayer structure, the two components are mixed at the interface between the two adhesive layers, and the appearance is Form a single-layer structure).

The storage modulus of the adhesive layer at 23°C is 9.5×10 ⁵ Pa or more and 3.0×10 ⁷ Pa or less, and preferably 9.9×10 ⁵ Pa or more and 2.0×10 ⁷ Pa or less. Furthermore, since the pressure when attaching the adhesive layer to the sealed object can be reduced, the storage modulus of the adhesive layer at 23°C is ^{preferably 1.3×10 7} Pa or less, 1.1×10 ⁷ Pa or less It is more preferable, and 1.0×10 ⁷ Pa or less is more preferable.

By setting the storage modulus of the adhesive layer at 23°C to 9.5×10 ⁵ Pa or more, when the device sealing adhesive sheet is cut into a predetermined shape, the adhesive layer can be not significantly deformed. Cut the punching knife into the adhesive sheet for sealing the device. Therefore, it is possible to prevent the adhesive from adhering to the unpeeled portion of the end portion of the peeling film, and to peel the peeling film efficiently. For example, by using a compound having a large cyclic ether equivalent as the cyclic ether compound (A), it becomes easy to obtain ^{an adhesive layer having a storage modulus at 23° C. of 9.5×10 5} Pa or more. Furthermore, by reducing the content of the cyclic ether compound (AL) in the adhesive layer, the storage modulus of the adhesive layer at 23° C. can be reduced. Moreover, by using a relatively rigid resin such as a phenoxy resin, even when the content of the cyclic ether compound (AL) in the adhesive layer is large, it can be easily stored at 23°C. Adhesive layer with a modulus of 9.5×10 ^{5 Pa or more.}

By setting the storage modulus of the adhesive layer at 23° C. to 3.0×10 ⁷ Pa or less, the adhesive layer has sufficient adhesive force at room temperature and excellent adhesion. For example, by increasing the amount of the cyclic ether compound (AL), it becomes easier to obtain an adhesive layer ^{with a storage modulus of 3.0×10 7 Pa or less at 23°C.} Furthermore, as described above, in the case where the adhesive layer includes a thermal cationic polymerization initiator, the cyclic ether compound (A) is a compound having a glycidyl ether group, which allows the adhesive layer to be stored at 23°C. The modulus is lowered, and it becomes easy to be 3.0×10 ⁷ Pa or less. A well-known dynamic viscoelasticity measuring device can be used to measure the storage modulus of the adhesive layer. Specifically, it can be measured according to the method described in the embodiment.

The adhesive layer has curability. That is, by performing a predetermined hardening treatment on the adhesive layer, the cyclic ether group in the cyclic ether compound (A) is reacted, and the adhesive layer is hardened to become an adhesive cured material layer. As the hardening treatment, heat treatment, illumination treatment, and the like can be cited. It can be appropriately determined according to the properties of the adhesive layer.

The storage modulus of the cured adhesive layer at 90°C is ^{preferably 1×10 8} Pa or more, and preferably 1×10 ^{9 to} 1×10 ¹¹ Pa. The hardened adhesive layer with a storage modulus of 1×10 ⁸ Pa or more at 90°C has excellent sealing properties, so it is more suitable as a sealing material. Furthermore, after the hardened adhesive layer is formed, it becomes easy to prevent the hardened adhesive layer from cracking and peeling during the manufacturing process of the device sealing body. A well-known dynamic viscoelasticity measuring device can be used to measure the storage modulus of the hardened adhesive layer. Specifically, it can be measured according to the method described in the embodiment.

The hardened adhesive layer has excellent adhesive strength. In the case of a 180° peel test at a temperature of 23°C and a relative humidity of 50%, the adhesive strength of the hardened adhesive layer is usually 1-20N/25mm, preferably 2.5-15N/25mm. For example, the 180° peel test can be performed under the conditions of a temperature of 23° C. and a relative humidity of 50% in accordance with the adhesive force measurement method described in JIS Z0237:2009.

When the adhesive sheet for device sealing of the present invention is used to form a sealing material in optical-related devices such as light-emitting devices, light-receiving devices, and display devices, the cured adhesive layer preferably has excellent colorless transparency. The total light transmittance of the cured adhesive layer with a thickness of 15 μm is preferably 85% or more, and more preferably 90% or more. There is no specific upper limit for the total light transmittance, but it is usually 99% or less. The total light transmittance can be measured according to JIS K7361-1:1997.

The moisture permeability of the hardened adhesive layer is usually 0.1~200g·m ^-2 ·day ^-1 , preferably ^1~ 150g·m ^-2 ·day -1. A well-known gas transmission rate measuring device can be used to measure the water vapor transmission rate.

[Peeling film] The pressure-sensitive adhesive sheet for device sealing of the present invention includes a first release film and a second release film. When using the adhesive sheet for device sealing, the release film is usually peeled off. At this time, the second release film is peeled and removed before the first release film. Since the second peeling film can be peeled and removed efficiently, the peeling force of the second peeling film is preferably lower than the peeling force of the first peeling film. In the following description, the "first release film" and the "second release film" are sometimes not distinguished, and they are simply referred to as "release film".

The peeling film serves as a support in the manufacturing process of the adhesive sheet for device sealing, and serves as a protective sheet for the adhesive layer before using the adhesive sheet for device sealing.

A conventionally known release film can be used as the release film. For example, the peeling film which has a peeling layer on the base material for peeling films is mentioned. A known release agent can be used to form the release layer.

Examples of the substrate for the release film include paper substrates such as glassine, coated paper, and forest paper; laminated paper in which thermoplastic resins such as polyethylene are laminated on the above-mentioned paper substrate; Plastic films such as polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, polyethylene resin, etc.; etc. Examples of the release agent include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long-chain alkane resins, alkyd resins, fluorine resins, and the like. The thickness of the release film is not particularly limited, and is usually about 20 to 250 μm.

[Adhesive sheet for device sealing] The adhesive sheet for device sealing of the present invention includes the aforementioned first release film and second release film, and the aforementioned adhesive layer interposed between these release films Examples of the pressure-sensitive adhesive sheet for device sealing of the present invention include a three-layer structure of a first release film/adhesive layer/second release film.

The manufacturing method of the adhesive sheet for device sealing of this invention is not specifically limited. For example, a casting method can be used to manufacture an adhesive sheet for device sealing.

When manufacturing the adhesive sheet for device sealing by a casting method, it can manufacture by the following method, for example. Two peeling films (the peeling film (A) and the peeling film (B)) having a peeling layer, and the coating liquid including the components constituting the adhesive layer are prepared. Using a well-known method, the coating liquid is applied to the surface of the release layer of the release film (A), and the obtained coating film is dried to form an adhesive layer. Next, the release film (B) can be placed on the adhesive layer so that the surface of the release layer of the release film (B) is in contact with the adhesive release layer, thereby obtaining an adhesive sheet for device sealing.

In the case of diluting the components constituting the adhesive layer to prepare a coating liquid, examples of the solvent used for preparing the coating liquid include aromatic hydrocarbon solvents such as benzene and toluene; ethyl acetate, butyl acetate, etc. Ester solvents; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone; aliphatic hydrocarbon solvents such as n-pentane, n-hexane, n-heptane, etc.; cyclopentane, cyclohexane, methyl ring Alicyclic hydrocarbon solvents such as hexane; etc. The above-mentioned solvents may be used singly or in combination of two or more kinds. The content of the solvent can be appropriately determined in consideration of coating properties and the like.

Examples of the coating method of the coating liquid include spin coating, spray coating, bar coating, knife coating, and roll coating. Method, blade coating method, die coating method, gravure coating method, etc.

As a method of drying the solvent in the coating film, hot air drying, hot roll drying, infrared irradiation, and conventionally known drying methods can be cited. The conditions for drying the coating film are, for example, 80 to 150°C for 30 seconds to 5 minutes, preferably 90 to 120°C for 1 minute to 4 minutes. By drying the coating film at 90°C or higher, it is easy to dry the coating film even if the drying time is 5 minutes or less, and the productivity is excellent.

The method of manufacturing a sealing body using the adhesive sheet for device sealing of this invention is not specifically limited. For example, by performing the following steps (a1) to (a5), or steps (b1) to (b5), the sealed object (device) can be sealed to produce a device sealing body.

Step (a1): Peel off the second release film of the pressure-sensitive adhesive sheet for device sealing to obtain an intermediate body for device sealing. Step (a2): Attach the adhesive layer exposed by performing step (a1) to the sealed object (device). Step (a3): Further peeling and removing the first peeling film from the intermediate for device sealing. Step (a4): Attach the adhesive layer exposed by performing step (a3) to the substrate (glass plate, gas barrier film, etc.). Step (a5): Harden the adhesive layer in a predetermined manner to form a cured adhesive layer.

Step (b1): Peel off the second release film of the pressure-sensitive adhesive sheet for device sealing to obtain an intermediate body for device sealing. Step (b2): Attach the adhesive layer exposed by performing step (b1) to the substrate (glass plate, gas barrier film, etc.). Step (b3): Further peeling and removing the first peeling film from the intermediate for device sealing. Step (b4): Attach the adhesive layer exposed by performing step (b3) to the sealed object (device). Step (b5): Harden the adhesive layer in a predetermined manner to form a cured adhesive layer.

In the manufacturing method of the device sealing body described above, from the viewpoint of ease of operation and productivity, in step (a2) or step (b2), the step of attaching the adhesive layer to the sealed object or the substrate, It is better to carry out at room temperature (15～35℃, the same below). Similarly, step (b4) is also preferably carried out at room temperature.

When the adhesive sheet for device sealing of the present invention is cut into a predetermined shape, the punching knife can be cut into the adhesive sheet for device sealing without causing significant deformation of the adhesive layer. Therefore, it is possible to prevent the adhesive from adhering to the unpeeled portion of the end of the peeling film, and the peeling film can be peeled off efficiently. Moreover, the adhesive hardened layer formed by using the adhesive layer constituting the adhesive sheet for device sealing of the present invention has excellent adhesive strength and water vapor barrier properties. Therefore, the adhesive sheet for device sealing of the present invention is suitable for use as a material for forming a sealing material in a device sealing body.

The device sealing body is not particularly limited. Examples of the device sealing body include optical related devices such as light emitting devices, light receiving devices, and display devices. In the case where the adhesive layer has high light transmittance, the adhesive sheet for device sealing of the present invention is preferably used as a forming material of the sealing material in the sealing body of the optical related device. Specific examples 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 sealing of the present invention is transparent, the adhesive sheet for device sealing of the present invention is suitable for use as organic EL displays, organic EL lighting, and liquid crystal displays. Forming materials for sealing materials in devices such as displays and electronic paper. [Example]

Hereinafter, examples are listed to illustrate the present invention in more detail. However, the present invention is not limited to the following examples.

[Compounds used in Examples or Comparative Examples] ・Cyclic ether compound (AL1): Hydrogenated bisphenol A type glycidyl ether epoxy resin [manufactured by Mitsubishi Chemical Corporation, trade name: YX8000, liquid at 25°C, epoxy equivalent: 205g/eq] ・Cyclic ether compound (AL2): Hydrogenated bisphenol A type glycidyl ether epoxy resin [manufactured by Mitsubishi Chemical Corporation, trade name: YX8034, liquid at 25°C, epoxy equivalent: 270g/eq] ・Binder resin (B1): (Phenoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name: YX7200B35, glass transition temperature (Tg): 150°C) ・Hardening agent (C1): Thermal cationic polymerization initiator: benzyl (4-hydroxyphenyl) (methyl) tetrakis (pentafluorophenyl) borate (manufactured by Sanshin Chemical Co., Ltd., trade name: Sunaid) SI-B3) ・Hardening agent (C2): Imidazole hardening agent (manufactured by Shikoku Chemical Industry Co., Ltd., product name: Curezol 2E4MZ) ・Silane coupling agent (D1): 8-glycidoxy octyl trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBM4803) ・Release film (E1): manufactured by Lintec Co., Ltd., product name: SP-PET752150 ・Release film (E2): Manufactured by Lindek Co., Ltd., product name: SP-PET381130

[Example 1] 130 parts by mass of cyclic ether compound (AL1), 100 parts by mass of binder resin (B1), 3.8 parts by mass of hardener (C1), and 0.2 parts by mass of silane coupling agent (D1) were dissolved in methyl ethyl ketone to Prepare the coating liquid. This coating solution was applied to the peeled surface of the release film (E1) (the first release film), and the resulting coating film was dried at 100°C for 2 minutes to obtain an adhesive layer with a thickness of 15μm . The peeling-treated surface of the peeling film (E2) (the second peeling film) was stuck on the upper side of this adhesive layer, and the pressure-sensitive adhesive sheet for device sealing was obtained.

[Example 2, Comparative Examples 1, 2] Except that the type and amount of each component constituting the adhesive layer were changed to the contents described in Table 1, the pressure-sensitive adhesive sheet for device sealing was obtained in the same manner as in Example 1.

The following tests were performed on the adhesive sheets for device sealing obtained in Examples 1, 2, and Comparative Examples 1, 2. The results are shown in Table 1.

(1) Storage modulus of the adhesive layer The adhesive layer of the adhesive sheet for device sealing obtained in the examples or comparative examples was laminated to a thickness of about 1 mm at 23° C. using a laminator, and the resulting laminate was used as a sample for measurement Use, measure its storage modulus. That is, for this measurement sample, a storage modulus measuring device (manufactured by Anton Paar, trade name: Physica MCR301) was used at a frequency of 1 Hz, a strain of 1%, and a heating rate of 3°C/ Measure the storage modulus in the temperature range of -20～+150℃ under different conditions. The measurement results at 23°C are shown in Table 1.

(2) Storage modulus of hardened adhesive layer The adhesive layer of the adhesive sheet for device sealing obtained in the Examples or Comparative Examples was laminated to a thickness of 200 μm at 23°C using a laminator, and the resulting laminate was heated at 110°C for 1 hour, and then Get its hardened product. Use this hardened product as a sample for measurement, and measure its storage modulus. That is, for this sample for measurement, a storage modulus measuring device (manufactured by TA Instrument, trade name: DMAQ800) was used at a frequency of 11 Hz, an amplitude of 5 μm, and a heating rate of 3°C/min. Under the conditions, the storage modulus in the temperature range of -20～+150℃ is measured. The measurement results at 90°C are shown in Table 1.

(3) Evaluation of the adaptability of the adhesive layer to the object to be sealed The adhesive sheets for device sealing obtained in the examples and comparative examples were cut to obtain test pieces having a width of 50 mm and a length of 150 mm. The adhesive layer exposed by peeling off the second release film of the obtained test piece was placed on an alkali-free glass plate under the conditions of a temperature of 23°C and a relative humidity of 50%, and a pressure roller was used to apply a pressure of 0.5 MPa. pressure. The state of the adhesive layer floating from the alkali-free glass plate was observed, and those without floating were evaluated as A, and those with floating were evaluated as B.

(4) Evaluation of cutting processability of adhesive sheets for device sealing Using an air-type sample cutting device, the adhesive sheets for device sealing obtained in the Examples and Comparative Examples were cut to a size of 150 mm in length and 165 mm in width. Specifically, a punching knife of the aforementioned size was cut from the side of the second release film of the pressure-sensitive adhesive sheet for device sealing to cut off the pressure-sensitive adhesive sheet for device sealing to obtain a test piece. The second release film of the obtained test piece was peeled and removed. At this time, the one where the adhesive layer was not peeled off from the first release film was evaluated as A, and the one where the adhesive layer was attached to the end of the second release film and the adhesive layer was peeled off from the first release film was evaluated as B.

[Table 1]

The following can be known from Table 1. The adhesive layer of the adhesive sheet for device sealing obtained in Examples 1 and 2 was excellent in adhesiveness at 23°C. Moreover, these pressure-sensitive adhesive sheets for device sealing also have excellent cutting workability, and can peel off and remove the release film efficiently. On the other hand, although the adhesive layer of the adhesive sheet for device sealing obtained in Comparative Example 1 was excellent in adhesion at 23°C, the storage modulus of the adhesive layer at 23°C was too low. This device The cutting processability of the adhesive sheet for sealing is poor. Furthermore, the adhesive layer of the adhesive sheet for device sealing obtained in Comparative Example 2 had an excessively high storage modulus at 23° C. and poor adhesion.

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Claims (11)

An adhesive sheet for device sealing, comprising a first peeling film and a second peeling film, and an adhesive layer interposed between the first peeling film and the second peeling film. The adhesive sheet for sealing a device is characterized in that The following conditions (I) and (II) are satisfied. Condition (I): The aforementioned adhesive layer includes one or more compounds with cyclic ether groups. Condition (II): The aforementioned adhesive layer is The storage modulus at 23°C is 9.5×10 ⁵ Pa or more and 3.0×10 ⁷ Pa or less. The adhesive sheet for device sealing according to claim 1, wherein at least one of the aforementioned compounds having a cyclic ether group is a compound that is liquid at 25°C. The pressure-sensitive adhesive sheet for device sealing according to claim 2, wherein the content of the compound having a cyclic ether group that is liquid at 25° C. relative to the entire pressure-sensitive adhesive layer is 53% by mass or more. The pressure-sensitive adhesive sheet for device sealing according to claim 2, wherein the content of the compound having a cyclic ether group that is liquid at 25° C. relative to the entire pressure-sensitive adhesive layer is 65% by mass or less. The adhesive sheet for device sealing according to claim 1, wherein the adhesive layer further includes a hardener, and at least one type of the hardener is a thermal cationic polymerization initiator. The adhesive sheet for device sealing according to claim 5, wherein all of the hardeners are thermal cationic polymerization initiators. The adhesive sheet for device sealing according to claim 5, wherein at least one of the aforementioned compounds having a cyclic ether group is a compound having a glycidyl ether group. The adhesive sheet for device sealing according to claim 5, wherein at least one of the aforementioned compounds having a cyclic ether group is an alicyclic epoxy resin. The adhesive sheet for device sealing according to claim 1, wherein the adhesive layer includes an adhesive resin, and at least one type of the adhesive resin is an adhesive resin having a glass transition temperature (Tg) of 60° C. or higher. The adhesive sheet for device sealing according to claim 1, wherein the storage modulus at 90°C of the layer obtained by curing the adhesive layer is 1×10 ⁸ Pa or more. The adhesive sheet for device sealing described in claim 1 is used to form a sealing material in an optical-related device.