TW201936877A - Curable resin composition for sealing - Google Patents

Abstract

The present invention provides a curable resin composition for sealing, which contains (A) a bifunctional alicyclic epoxy resin having a molecular weight of less than 1,000, (B) a polyfunctional epoxy resin having a molecular weight of 1,000 or more, (C) a bifunctional vinyl ether compound, and (D) a cationic polymerization initiator.

Description

Curing resin composition for sealing

The present invention relates to a curable resin composition for sealing, and more specifically to a light-emitting element such as a semiconductor device, in particular, an organic electroluminescence device (hereinafter also referred to as an "organic EL device"), or a light receiving device such as a solar cell. A curable resin composition for sealing which is suitable for sealing of a photoelectric conversion element, such as a component.

In the organic EL element, a light-emitting element using an organic substance for a light-emitting material has been attracting attention in recent years because light emission with low voltage and high luminance can be obtained. In order to improve the durability of the organic EL element, it is necessary to block the inside of the element from oxygen or moisture in the outside air, for example, to form a sealing layer of the resin composition by covering the entire surface of the light-emitting layer formed on the substrate. Layer to seal the organic EL element.

In the resin composition, a thermosetting or photocurable resin composition is often used. For example, Patent Document 1 proposes a photocurable resin composition containing a low molecular weight polyfunctional epoxy resin and a high epoxy resin composition. A monofunctional or polyfunctional epoxy resin having a molecular weight and a decane coupling agent containing a glycidyl group in the molecule. Although the resin composition has an advantage that the amount of generated exhaust gas of the cured product is small, the fluidity at room temperature is low due to high viscosity, and there is a disadvantage that it is difficult to form a sealing layer having the same properties.

[Previous Technical Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-126699

[Questions to be solved by the invention]

In view of the above, the present invention has been made in an effort to provide a curable resin composition for sealing a cured product which is excellent in fluidity at room temperature and has a small amount of exhaust gas.
In addition, it is an object of the present invention to provide a curable resin composition for sealing which is excellent in fluidity at room temperature, has a small amount of exhaust gas generation, and has high transparency.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the present inventors have found that an epoxy resin having a molecular weight of a certain or more is hardened by a mixture of a low molecular weight bifunctional alicyclic epoxy resin and a bifunctional vinyl ether compound. The present invention has been completed by forming a curable resin composition which is excellent in fluidity at room temperature and which is cured by hardening to form a cured product having high transparency and low generation of exhaust gas.

That is, the present invention has the following features.
[1] A curable resin composition for sealing comprising (A) a 2-functional alicyclic epoxy resin having a molecular weight of less than 1,000, (B) a polyfunctional epoxy resin having a molecular weight of 1,000 or more, and (C) 2 A functional vinyl ether compound and (D) a cationic polymerization initiator.
[2] The curable resin composition for sealing according to the above [1], wherein the (B) polyfunctional epoxy resin has a molecular weight of 10,000 or less.
[3] The curable resin composition for sealing according to the above [1], wherein the (B) polyfunctional epoxy resin has a cyclic skeleton.
[4] The curable resin composition for sealing according to any one of the above [1], wherein the (C) bifunctional vinyl ether compound has a molecular weight of 1,000 or less.
[5] The curable resin composition for sealing according to any one of the above [1], wherein the viscosity at 25 ° C is less than 300 mPas.
[6] The curable resin composition for sealing according to any one of the above [1], wherein the (D) cationic polymerization initiator is a thermal cationic polymerization initiator.
[7] The curable resin composition for sealing according to any one of the above [1], wherein the (A) bifunctional alicyclic epoxy resin has a molecular weight of 100 or more.
[8] The curable resin composition for sealing according to any one of the above [1] to [7], which is used for sealing an organic EL element.
[9] An organic EL device in which the organic EL device is sealed with a cured product of the curable resin composition according to any one of the above [1] to [7].

[Effect of the invention]

The curable resin composition of the present invention has a low viscosity at room temperature and high fluidity, and a composition layer (coating layer) which can easily form the same property can be formed by coating. Further, even if the cured product is exposed to a high temperature, a sealing layer having a small amount of exhaust gas generated and preventing deterioration of the element for a long period of time can be formed. Moreover, since the cured product has high transparency, it is particularly advantageous for sealing a photoelectric conversion element such as a light-emitting element such as an organic EL element or a light-receiving element such as a solar cell.

Hereinafter, the present invention will be described based on suitable embodiments thereof. The examples, the descriptions, and the like described later may be combined as long as they do not contradict each other.
The curable resin composition of the present invention (hereinafter also referred to simply as "resin composition") contains at least (A) a 2-functional alicyclic epoxy resin having a molecular weight of less than 1,000, and (B) a molecular weight of 1,000 or more. A polyfunctional epoxy resin, a (C) 2-functional vinyl ether compound, and (D) a cationic polymerization initiator are main features.

<(A) 2-functional alicyclic epoxy resin having a molecular weight of less than 1,000>
The curable resin composition of the present invention contains (A) a two-functional alicyclic epoxy resin having a molecular weight of less than 1,000 (hereinafter also referred to as "(A) component"). The component (A) is not particularly limited as long as it has two alicyclic epoxy groups in one molecule and a compound having a molecular weight of less than 1,000. The "alicyclic epoxy group" is a group in which an adjacent two carbon atoms of an alicyclic ring constituting an alicyclic group form an ethylene oxide (Oxirane) ring (epoxy group) between oxygen atoms, for example, The epoxycyclopentyl group, the epoxycyclohexyl group and the like are exemplified, and an epoxycyclohexyl group is preferred. The component (A) may have a alicyclic condensed alicyclic structure in which a plurality of alicyclic epoxy groups are condensed by an alicyclic moiety.

The component (A) is preferably a compound represented by the formula (I).

In the formula (I), X represents a single bond or a linking group (a divalent group having one or more atoms), and the linking group is a divalent hydrocarbon group, a carbonyl group, an ether bond, an ester bond, a carbonate group, or a guanamine bond. , or a plurality of links to these bases].

In the compound represented by the formula (I), the divalent hydrocarbon group exemplified as the linking group is preferably a linear or branched chain alkyl group or a divalent alicyclic hydrocarbon group having a carbon number of 1 to 18 (especially It is a divalent cycloalkyl group). Examples of the linear or branched chain alkyl group having 1 to 18 carbon atoms include a methylene group, a methylmethylene group, a dimethylmethylene group, an exoethyl group, a propyl group, and a Sanya group. Methyl and the like. Examples of the divalent alicyclic hydrocarbon group include a 1,2-cyclopentyl group, a 1,3-cyclopentyl group, a cyclopentylene group, a 1,2-cyclohexyl group, and a 1,3-cyclohexyl group. a divalent cycloalkyl group (including a cycloalkylidene group) such as a 1,4-cyclohexyl group or a cyclohexylene group.

Representative examples of the compound represented by the formula (I) include compounds represented by the following formulas (I-1) to (I-7). In the following formula (I-6), n represents an integer of 1 to 7.

Commercially available products can be used as the compound represented by the formula (I), and examples thereof include "CELLOXIDE 2021P", "CELLOXIDE 2081", "CELLOXIDE 8000" (above, manufactured by Daicel Corporation), "Synasia S-21E", and "Synasia S-". 28", "Synasia S-60" (above, manufactured by Synasia), "TTA60", "TTA2081", "TTA2083" (above, Tetrachem).

In the present invention, the component (A) has a molecular weight of less than 1,000, preferably 900 or less, more preferably 800 or less, still more preferably 700 or less, from the viewpoint of fluidity at room temperature of the curable resin composition. Jia is below 600. Further, the lower limit of the molecular weight is not particularly limited, but from the viewpoint of suppressing generation of exhaust gas, the molecular weight is preferably 100 or more, more preferably 125 or more, and particularly preferably 150 or more.

In the present invention, the component (A) preferably has a viscosity (25 ° C) of from 10 to 1,000 mPas, more preferably from 25 to 750 mPas, from the viewpoint of fluidity at room temperature of the curable resin composition. Further, the "viscosity at 25 ° C" and "viscosity (25 ° C)" in the present invention mean "the viscosity at 25 ° C measured by a vibrating viscometer".

In the present invention, the epoxy equivalent of the component (A) is preferably from 50 to 500 g/eq, more preferably from 75 to 450 g/eq, even more preferably from 90 to 400 g/eq, from the viewpoint of reactivity and the like. In the present specification, the "epoxy equivalent" is a number (g/eq) of a resin containing 1 gram equivalent of an epoxy group, and is measured in accordance with the method specified in JIS K 7236.

In the present invention, one type or two or more types of the component (A) can be used. The content of the component (A) in the curable resin composition is preferably 40% by mass or more, and more preferably 45% by mass or more based on the total nonvolatile content of the curable resin composition. In addition, the total nonvolatile content of the curable resin composition is preferably 75% by mass or less, more preferably 70% by mass or less, and particularly preferably 65% by mass or less, from the viewpoint of the reactivity at the time of curing.

<(B) Multifunctional epoxy resin having a molecular weight of 1,000 or more>
The curable resin composition of the present invention contains (B) a polyfunctional epoxy resin having a molecular weight of 1,000 or more (hereinafter also referred to simply as "(B) component"). The component (B) is not particularly limited as long as it has an epoxy group having two or more epoxy groups per molecule and a molecular weight of 1,000 or more. In the present specification, when the component in the resin composition is a polymer, the molecular weight means "weight average molecular weight".
Here, the weight average molecular weight is measured by a gel permeation chromatography (GPC) method (in terms of polystyrene). By the weight average molecular weight of the GPC method, specifically, LC-9A/RID-6A manufactured by Shimadzu Corporation can be used as a measuring device, and Shodex K-800P/K-804L/K-804L manufactured by Showa Denko Co., Ltd. can be used as the column. Using chloroform as the mobile equivalent, it was measured at a column temperature of 40 ° C, and was calculated using a calibration curve of standard polystyrene.

The component (B) is preferably an epoxy resin having a cyclic skeleton, and preferably (B1) an aromatic epoxy resin or (B2) an epoxy resin having an alicyclic skeleton. Further, the number of the average epoxy groups per molecule of the component (B) is preferably from 2 to 10, more preferably from 2 to 8.

Examples of the (B1) aromatic epoxy resin include a bisphenol A epoxy resin, a biphenyl epoxy resin, a biphenyl aralkyl epoxy resin, a naphthol epoxy resin, and a naphthalene epoxy resin. Bisphenol F type epoxy resin, bisphenol S type epoxy resin, aromatic epoxy propyl amine type epoxy resin (for example, tetraepoxypropyldiaminodiphenylmethane, triepoxypropyl-p- Aminophenol, toluidine, diepoxypropyl aniline, phenolic novolac epoxy resin, cresol novolac epoxy resin, bisphenol A phenolic epoxy resin, bisphenol Di-epoxypropyl etherate, diepoxypropyl etherate of naphthalenediol, diglycidyl etherate of phenol, and alkyl substituents, halides, etc. of such epoxy resins. Among them, from the viewpoint of transparency, a bisphenol A type epoxy resin and a bisphenol F type epoxy resin are preferable. Examples of the aromatic epoxy resin include "1004" of bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 875 to 975 g/eq, weight average molecular weight: 1650), and bisphenol F type epoxy. Resin "4004P" (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 840 to 975 g/eq, weight average molecular weight: 1815).

(B2) The epoxy resin having an alicyclic skeleton may, for example, be (i) a compound having an alicyclic epoxy group, (ii) a compound in which an alicyclic epoxy group is directly bonded by a single bond, and (iii) having A compound having a structure in which an epoxy ring directly bonds to a glycidyl ether skeleton and/or a diepoxypropylamine skeleton.

Examples of the (i) compound having an alicyclic epoxy group include compounds represented by the following formulas (b-1), (b-2), (b-3), and (b-4). R in the following formula (b-1) is an alkylene group having 1 to 8 carbon atoms, and examples thereof include a methylene group, an exoethyl group, a propyl group, an exo-propyl group, a butyl group, and an isobutyl group. a linear or branched chain alkyl group of s-butylene, pentyl, hexyl, heptyl, octyl, etc., wherein l in the following formula (b-1) represents an integer of 6 to 30 m in the following formula (b-2) represents an integer of 7 to 30, and n1 and n2 in the following formula (b-3) each represent an integer of 2 to 30, and n3 to n6 in (b-4). Each represents an integer from 1 to 30.

(ii) The compound represented by the following formula (II) is exemplified as the compound in which the alicyclic epoxy group is directly bonded by a single bond.

In the formula (II), R' is a group from which p-OH groups are removed from the p-valent alcohol, and p and n each represent a natural number. Examples of the p-valent alcohol [R'-(OH) _p ] include a polyol such as 2,2-bis(hydroxymethyl)-1-butanol or the like (an alcohol having 1 to 15 carbon atoms). p is preferably from 1 to 6, and n is preferably from 1 to 30. When p is 1, n is 2 or more, and when p is 2 or more, n in the individual ( ) (in the parentheses) may be the same or different. Specific examples of the above compound include 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol. (trade name "EHPE3150", made by Daicel Co., Ltd.).

Examples of the compound having a structure in which the alicyclic ring-bonded epoxypropyl ether skeleton and/or the diepoxypropylamine skeleton are (iii) include a hydrogenated bisphenol A type epoxy resin and a hydrogenated bisphenol F type ring. Oxygen resin, dicyclopentadiene type epoxy resin, and the like. Further, examples thereof include a biphenyl type epoxy resin, a biphenyl aralkyl type epoxy resin, a naphthol type epoxy resin, a naphthalene type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol S type epoxy resin. Aromatic epoxy propyl amine type epoxy resin (for example, tetraglycidyl propyl diamino diphenylmethane, triepoxypropyl-p-aminophenol, toluidine propyl toluidine, two Epoxy propyl aniline, etc.), phenol novolak type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol diepoxypropyl etherate, naphthalene glycol epoxide An aromatic ring of an aromatic epoxy resin such as a propyl etherate or a phenolic di-epoxypropyl etherate is converted into an alicyclic epoxy resin by hydrogen addition. Among them, from the viewpoint of transparency, a hydrogenated bisphenol A type epoxy resin and a hydrogenated bisphenol F type epoxy resin are preferable. Specific examples of the compound include "YX-8040" (manufactured by Mitsubishi Chemical Corporation), an epoxy equivalent: 1000 g/eq, and a weight average molecular weight: 3831) of a hydrogenated bisphenol A type epoxy resin.

The component (B) has a molecular weight (weight average molecular weight) of 1,000 or more, preferably 1,500 or more, from the viewpoint of suppressing the amount of exhaust gas generated. The upper limit of the molecular weight (weight average molecular weight) is not particularly limited, but the molecular weight (weight average molecular weight) is preferably 10,000 or less, and more preferably 5,000, from the viewpoint of fluidity at room temperature of the curable resin composition. the following.

The epoxy equivalent of the component (B) is preferably from 50 to 3,000 g/eq, more preferably from 80 to 2,000 g/eq, still more preferably from 100 to 1,500 g/eq, from the viewpoint of reactivity and the like. In the present specification, the "epoxy equivalent" is a number of grams (g/eq) of a resin containing one gram equivalent of an epoxy group, and is measured in accordance with the method specified in JIS K 7236.

The component (B) may be either liquid or solid, and a liquid epoxy resin and a solid epoxy resin may be used in combination. Here, the "liquid" and "solid" refer to the state of the epoxy resin at normal temperature (25 ° C).

A commercially available product can be used as the component (B), and as the (B1) aromatic epoxy resin, for example, "1004" of bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 875 to 975 g/eq, Weight average molecular weight: 1650) and the like. In addition, as the epoxy resin having an alicyclic skeleton (B2), "EHPE 3150" (manufactured by Daicel Corporation, compound name: 2,2-bis(hydroxymethyl)-1-butanol 1,2- Epoxy-4-(2-oxiranyl)cyclohexane adduct, epoxy equivalent: 70-190 g/eq, weight average molecular weight: 2400), hydrogenated bisphenol A epoxy resin "YX- 8040" (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 1000 g/eq, weight average molecular weight: 3831) and the like.

In the present invention, one or two or more kinds of the component (B) can be used. The content of the component (B) in the curable resin composition is preferably 2.5% by mass or more based on the total nonvolatile content of the curable resin composition, from the viewpoint of effectively suppressing the amount of exhaust gas generated. Preferably, it is 5 mass% or more. In addition, from the viewpoint of maintaining the fluidity at room temperature, it is preferably 30% by mass or less, and more preferably 25% by mass or less based on the total nonvolatile content of the curable resin composition.

<(C)2-functional vinyl ether compound>
The curable resin composition of the present invention contains a bifunctional vinyl ether compound (hereinafter also referred to as "(C) component"). When the component (C) is a compound having two vinyl ether groups in one molecule, it is not particularly limited and can be used.

Specific examples of the component (C) include 1,4-butanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, cyclohexane dimethanol divinyl ether, and B. Diol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, 1,8 -octanediol divinyl ether, 1,9-nonanediol divinyl ether, trimethylolpropane divinyl ether, bisphenol A divinyl ether, bisphenol F divinyl ether, 3,3 - bis(vinyloxymethyl) oxetane (Oxetane), isosorbide (Isosorbide) divinyl ether, and the like. Among them, cyclohexane dimethanol divinyl ether and diethylene glycol divinyl ether are preferred.
A commercially available product can be used as the component (C), and "CHDVE" (manufactured by Japan Carbide Co., Ltd., molecular weight 196.29) and "DEGDVE" of diethylene glycol divinyl ether (Japan Carbide) can be cited as cyclohexane dimethanol divinyl ether. Company system, molecular weight 158.20) and so on.

The component (C) is preferably a molecular weight of 1,000 or less, more preferably a molecular weight of 500 or less, still more preferably 400 or less.

In the present invention, one or two or more kinds of the component (C) can be used.

The content of the component (C) in the curable resin composition is preferably 20% based on the total nonvolatile content of the curable resin composition from the viewpoint of fluidity of the curable resin composition maintained at room temperature. The mass% or more is more preferably 25% by mass or more. Moreover, from the viewpoint of suppressing the exhaust gas, the total nonvolatile content of the curable resin composition is preferably 50% by mass or less, and more preferably 45% by mass or less.

<(D) Cationic Polymerization Starter>
The curable resin composition of the present invention contains a cationic polymerization initiator (hereinafter also referred to as "(D) component"). When the component (D) acts on the epoxy group of the component (A), the epoxy group of the component (B), and the vinyl group of the component (C), the component (A), the component (B), and the component (C) may be used. The individual cationic polymerization initiator may be a photocationic polymerization initiator or a thermal cationic polymerization initiator. In other words, the curable resin composition of the present invention may be a photocurable resin composition or a thermosetting resin composition.

The photocationic polymerization initiator is used as a solid function of the hardener ((polymer A) component, (B) component, and ultraviolet light irradiation, which is also called a photoacid generator, a light hardener, or a photocation generator. (C) The function of the ingredient).

Examples of the photocationic polymerization initiator include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, p-(phenylthio)phenyldiphenylphosphonium hexafluoroantimonate, and p. -(phenylthio)phenyldiphenylphosphonium hexafluorophosphate, 4-chlorophenyldiphenylphosphonium hexafluorophosphate, 4-chlorophenyldiphenylphosphonium hexafluoroantimonate, double [4- (Dilfonio) phenyl] sulfide bishexafluorophosphate, bis[4-(diphenyldithiol (Sulfonio)) phenyl] sulfide dihexafluoroantimonate (2,4-Cyclopentadien-1-yl)[(1-methylethyl)benzene]-Fe-hexafluorophosphate, diallylhydrazine hexafluoroantimonate or the like. These photocationic polymerization initiators may be used alone or in combination of two or more.

In the present invention, the thermal cationic polymerization initiator is more advantageous than the photocationic polymerization initiator from the viewpoint that the surface of the organic EL element can be sealed without irradiation with light, and can be preferably used. The thermal cationic polymerization initiator is also called a thermal acid generator, a thermal hardener or a thermal cation generator, and functions as a hardener (polymerization (A) component, (B) component, and (C) according to the curing temperature. The function of the ingredients).

The thermal cationic polymerization initiator is not particularly limited, but is preferably an organic onium salt compound in which a cationic component and an anionic component are paired. Examples of the cationic component include organic hydrazine, oxonium, organic ammonium, organic hydrazine, and organic iodonium. Further, examples of the anion component include BF ₄ ^- , B (C ₆ F ₅ ) ₄ ^- , SbF ₄ ^- , Sb(C ₆ F ₅ ) ₄ ^- , AsF ₆ ^- , PF ₆ ^- , PF ₆ ^- , CF ₃ SO ₃ ^- , C ₄ F ₉ SO ₃ ^- or (CF ₃ SO ₂ ) ₃ C ^- and the like. Examples of the commercial product of the thermal cationic polymerization initiator include TA-60, TA-60B, TA-100, TA-120, and TA-160 (above, manufactured by San-Apro Co., Ltd.), and K-PURE (registered). Trademark] TAG-2678, same as TAG-2681, with TAG-2689, with TAG-2690, with TAG-2700, with CXC-1612, with CXC-1614, with CXC-1615, with CXC-1616, with CXC-1733 Same as CXC-1738, the same CXC-1742, the same CXC-1802, the same CXC-1821 (the above is made by King Industries), SAN-AID SI-45, the same SI-45L, the same SI-60, the same SI-60L Same as SI-80, same SI-80L, same SI-100, same SI-100L, same SI-110, same SI-110L, same SI-150, same SI-150L, same SI-180, same SI-180L Same as SI-B2, the same SI-B2A, the same SI-B3, the same SI-B3A, the same SI-B4, the same SI-B5, the same SI-200, the same SI-210, the same SI-220, the same SI-300 Same as SI-360 (above is Sanxin Chemical Industry Co., Ltd.).

Among them, a salt having a 4-stage ammonium cation is preferred, and a salt composed of a 4-grade ammonium cation and a borate anion (BF ₄ ^- , B(C ₆ F ₅ ) ₄ ^-, etc.), and a 4-grade ammonium is more preferred. a salt composed of a cation and an anthracene anion (SbF ₄ ^- , Sb(C ₆ F ₅ ) ₄ ^{- ,} etc.), particularly preferably a 4-grade ammonium cation and a borate anion (BF ₄ ^- , B(C ₆ F ₅ ) ₄ ^-, etc.) composed of a salt.

Specific examples of the salt composed of the fourth-order ammonium cation and the borate anion (BF ₄ ^- , B(C ₆ F ₅ ) ₄ ^- or the like) include, for example, dimethylphenyl (4-methoxybenzyl group). Ammonium quinone (pentafluorophenyl) borate, dimethylphenyl (4-methylbenzyl) ammonium hexafluoroiridium (pentafluorophenyl) borate, methylphenyl dibenzyl ammonium ruthenium (pentafluoro Phenyl)borate, phenyltribenzylammonium ruthenium (pentafluorophenyl)borate, dimethylphenyl (3,4-dimethylbenzyl)ammonium ruthenium (pentafluorophenyl)borate, N , N-diethyl-N-benzylaniline boron tetrafluoride, and the like.

In the present invention, one or two or more kinds of the component (D) can be used.

In the present invention, the content of the component (D) in the curable resin composition is preferably 0.1 to 5.0% by mass, and more preferably 0.1 to 2.5% by mass based on the total nonvolatile content of the curable resin composition.

When the component (D) is a thermal cationic polymerization initiator, it is suitable for exhibiting a substantial function as a curing agent at a relatively low temperature. Specifically, it is preferable to exhibit a substantial function as a curing agent at 150 ° C or lower. Thereby, it is possible to reduce the influence on the substrate or the thermal deterioration of the element due to the heating of the substrate or the sealing substrate having the element due to the heat hardening step when the resin material having low heat resistance is formed. A more preferable temperature to function as a hardener is 120 ° C or less.

The curable resin composition of the present invention contains at least the composition of the above components (A) to (D), and is preferably a composition composed of the above components (A) to (D). The following components ((E) thermoplastic resin, (F) hygroscopic filler, etc.) may be blended if necessary.

<(E) thermoplastic resin>
The curable resin composition of the present invention may contain (E) a thermoplastic resin from the viewpoint of imparting flexibility to a sealing layer, that is, a coating property (preventing shrinkage) of a curable resin composition, and the like. (hereinafter, also referred to as "(E) component)"). Examples of the thermoplastic resin include a phenoxy resin, a polyvinyl acetal resin, a polyimide resin, a polyamide amide resin, a polyether oxime resin, a polyfluorene resin, a polyester resin, and (meth) Acrylic polymer or the like. These thermoplastic resins may be used alone or in combination of two or more.

The weight average molecular weight of the component (E) is preferably 10,000 or more, more preferably 15,000 or more, and particularly preferably 20,000 or more. However, when the weight average molecular weight is too large, the compatibility with the component (B) tends to be lowered. Therefore, the weight average molecular weight is preferably 1,000,000 or less, more preferably 800,000 or less.

As the component (E), a phenoxy resin is particularly preferred. The phenoxy resin has good compatibility with a thermosetting resin (especially an epoxy resin), and is advantageous for the moisture blocking property of the cured product obtained from the curable resin composition. The weight average molecular weight of the phenoxy resin is preferably 15,000 or more, more preferably 20,000 or more, preferably 1,000,000 or less, more preferably 800,000 or less.

Suitable phenoxy resins include those selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, phenolic skeleton, biphenyl skeleton, anthracene skeleton, dicyclopentadiene. One or more skeletons of the skeleton and the norbornene skeleton. One type or two or more types may be used for the phenoxy resin.

Examples of the commercially available phenoxy resin include 1256 (a phenoxy resin containing a bisphenol A skeleton) and 4275 (a phenoxy resin containing a bisphenol A skeleton and a bisphenol F skeleton) manufactured by Mitsubishi Chemical Corporation. Wait.

When the curable resin composition of the present invention contains the component (E) (particularly a phenoxy resin), the content thereof is preferably from 1 to 40% by mass, more preferably from 1 to 40% by mass based on the total nonvolatile content of the curable resin composition. 5 to 30% by mass.

<(F) hygroscopic filler>
In the curable resin composition of the present invention, in order to impart a higher water vapor permeability to the sealing layer as a cured product, a hygroscopic filler (hereinafter also referred to simply as "(F) component)") may be blended. (F) The hygroscopic filler is not particularly limited as long as it has a function of absorbing moisture, but is preferably a hygroscopic metal oxide. The hygroscopic metal oxide means a metal oxide which is capable of absorbing moisture and chemically reacts with moisture-absorbing moisture to become a hydroxide. Specific examples thereof include calcium oxide, magnesium oxide, cerium oxide, magnesium oxide, cerium oxide, unfired hydrotalcite, semi-fired hydrotalcite, calcined hydrotalcite, and calcined dolomite. Among them, from the viewpoint of hygroscopicity, it is preferred to semi-fire into hydrotalcite and calcined hydrotalcite.

Hydrotalcites can be classified into unfired hydrotalcites, semi-fired hydrotalcites, and calcined hydrotalcites.

The unfired hydrotalcite is, for example, a metal hydroxide having a layered crystal structure represented by natural hydrotalcite (Mg ₆ Al ₂ (OH) ₁₆ CO ₃ · 4H ₂ O), for example, a layer as a basic skeleton. [Mg _1-X Al _X (OH) ₂ ] ^X+ is composed of an intermediate layer [(CO ₃ ) _X/2 · mH ₂ O] ^X- . The unfired hydrotalcite of the present invention contains the concept of a hydrotalcite compound such as synthetic hydrotalcite. Examples of the hydrotalcite-like compound include those represented by the following formula (I) and the following formula (II).

(wherein, M ²⁺ represents a divalent metal ion such as Mg ²⁺ or Zn ²⁺ , M ³⁺ represents a trivalent metal ion such as Al ³⁺ or Fe ³⁺ , and A ^n- represents CO ₃ ^2- or Cl. ^- n-valent anion of NO ₃ ^-, etc., and 0 < x < 1, 0 ≦ m < 1, n is a positive number).
In the formula (I), M ^{2+ is} preferably Mg ²⁺ , M ^{3+ is} preferably Al ³⁺ , and A ^{n- is} preferably CO ₃ ^2- .

(wherein, M ²⁺ represents a divalent metal ion such as Mg ²⁺ or Zn ²⁺ , A ^n- represents an n-valent anion such as CO ₃ ^2- , Cl ⁻ or NO ³ , and x represents a positive number of 2 or more, z represents a positive number below 2, m is a positive number, and n is a positive number).
In the formula (II), M ^{2+ is} preferably Mg ²⁺ , and A ^{n- is} preferably CO ₃ ^2- .

The semi-fired hydrotalcite refers to a metal hydroxide having a layered crystal structure obtained by firing uncalcined hydrotalcite to reduce or eliminate the amount of interlayer water. The term "interlayer water" as used in the composition formula refers to the "H ₂ O" described in the composition formula of the unfired natural hydrotalcite and hydrotalcite-like compound.

On the other hand, the calcined hydrotalcite refers to a metal oxide having an amorphous structure obtained by firing unsintered hydrotalcite or semi-baked hydrotalcite, not only interlayer water but also having a hydroxyl group which is dehydrated by condensation.

Unfired hydrotalcite, semi-fired hydrotalcite and calcined hydrotalcite can be distinguished by saturated water absorption. The saturated water absorption of the semi-baked hydrotalcite is 1% by mass or more and less than 20% by mass. On the other hand, the saturated water absorption of the unfired hydrotalcite is less than 1% by mass, and the saturated water absorption of the calcined hydrotalcite is 20% by mass or more.

The term "saturated water absorption rate" as used herein refers to the measurement of 1.5 g of unfired hydrotalcite, semi-fired hydrotalcite or calcined hydrotalcite on a scale, and after initial mass measurement, at atmospheric pressure, 60 ° C, 90 The mass increase rate with respect to the initial mass when the small environmental tester (SH-222 manufactured by ESPEC Co., Ltd.) of %RH (relative humidity) was allowed to stand for 200 hours can be obtained by the following formula (i).

Saturated water absorption (% by mass)
=100×(mass after moisture absorption - initial quality) / initial quality (i)

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

Further, the unfired hydrotalcite, the semi-calcined hydrotalcite, and the calcined hydrotalcite can be distinguished by the thermal weight reduction rate measured by thermogravimetric analysis. The semi-calcined hydrotalcite has a thermal weight reduction rate of less than 15% by mass at 280 ° C, and its thermal weight reduction rate at 380 ° C is 12% by mass or more. On the other hand, the thermogravimetric reduction rate of the unfired hydrotalcite at 280 ° C was 15% by mass or more, and the thermal weight reduction rate of the calcined hydrotalcite at 380 ° C was less than 12% by mass.

The thermogravimetric analysis was carried out using a TG/DTA EXSTAR 6300 manufactured by Hitachi High-Technologies Co., Ltd., and 5 mg of hydrotalcite was weighed in a sample tray made of magnesium, and opened in an uncovered state. From 30 ° C to 550 ° C in a nitrogen flow rate of 200 mL/min. The temperature was raised at a rate of 10 ° C /min. The heat weight reduction rate can be obtained by the following formula (ii).

Thermal weight reduction rate (% by mass)
=100× (mass before heating - mass at the specified temperature) / mass before heating (ii)

Further, the unfired hydrotalcite, the semi-fired hydrotalcite, and the calcined hydrotalcite can be distinguished by the peak and relative intensity ratios measured by powder X-ray diffraction. The semi-baked hydrotalcite system means that by powder X-ray diffraction, it splits into two peaks around 8 to 18° in 2θ, or has a peak of a shoulder by a combination of two peaks, and a low angle. The peak intensity of the side or the diffraction intensity of the shoulder (= low angle side diffraction intensity), the peak intensity appearing at the high angle side or the diffraction intensity of the shoulder (= high angle side diffraction intensity) (low The corner side diffraction intensity / high angle side diffraction intensity) is 0.001 to 1,000. On the other hand, the unfired hydrotalcite has a peak near 8 to 18°, or the peak at the low angle side or the relative intensity ratio of the peak or the diffraction intensity of the shoulder at the high angle side becomes Outside the scope of the foregoing. The calcined hydrotalcite does not have a characteristic peak in the region of 8° to 18°, and has a characteristic peak at 43°. The powder X-ray diffraction measurement was performed by a powder X-ray diffraction device (manufactured by PANalytical Co., Ltd., Empyrean), a cathode CuKα (1.5405 Å), a voltage: 45 V, a current: 40 mA, a sampling width: 0.0260°, and a scanning speed: 0.0657. °/s, measurement of the diffraction angle range (2θ): 5.0131 to 79.9711 °. The peak search system uses the peak search function of the software attached to the diffractive device. The minimum significance: 0.50, minimum peak chip: 0.01°, maximum peak chip: 1.00°, peak bottom width. The condition of: 2.00°, method: minimum value of 2 times of differentiation is performed.

Semi calcined hydrotalcite BET specific surface area is preferably 1 ~ 250m ² / g, more preferably 5 ~ 200m ² / g. The BET specific surface area of the semi-baked hydrotalcite was measured by a BET multipoint method using a specific surface area measuring apparatus (manufactured by Macsorb HM Model 1210 MOUNTECH Co., Ltd.) to adsorb the nitrogen gas on the surface of the sample.

The average particle diameter of the semi-baked hydrotalcite is preferably from 1 to 1,000 nm, more preferably from 10 to 800 nm. The average particle diameter of the semi-fired hydrotalcite is measured by a laser diffraction scattering particle size distribution (JIS Z 8825), and the median diameter of the particle size distribution when the particle size distribution is prepared on a volume basis.

The component (F) can be used as a surface treatment agent. As the surface treatment agent to be used for the surface treatment, for example, a higher fatty acid, an alkyl decane, a decane coupling agent or the like can be used, and among them, a higher fatty acid or a alkyl decane is preferable. One type or two or more types of surface treatment agents can be used.

Examples of the higher fatty acid include higher fatty acids having 18 or more carbon atoms such as stearic acid, octadecanoic acid, myristic acid, and palmitic acid. Among them, stearic acid is preferred. These may be used alone or in combination of two or more. Examples of the alkyl decanes include methyltrimethoxydecane, ethyltrimethoxydecane, hexyltrimethoxydecane, octyltrimethoxydecane, decyltrimethoxydecane, and octadecyltrimethoxydecane. And dimethyldimethoxydecane, octyltriethoxydecane, n-octadecyldimethyl(3-(trimethoxydecyl)propyl)ammonium chloride, and the like. These may be used alone or in combination of two or more. Examples of the decane coupling agent include 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropyltriethoxydecane, and 3-glycidoxypropyl (dimethoxy). Epoxy decane coupling agent such as methyl decane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxy decane; 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethyl a mercapto decane coupling agent such as oxydecane, 3-mercaptopropylmethyldimethoxydecane and 11-decylundecyltrimethoxydecane; 3-aminopropyltrimethoxydecane, 3-amine Propyltriethoxydecane, 3-aminopropyldimethoxymethylnonane, N-phenyl-3-aminopropyltrimethoxydecane, N-methylaminopropyltrimethoxy Decane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, and N-(2-aminoethyl)-3-aminopropyldimethoxymethyldecane Amino decane coupling agent; ureido decane coupling agent such as 3-ureidopropyltriethoxy decane, vinyl trimethoxy decane, vinyl triethoxy decane and vinyl methyl diethoxy Vinyl decane coupling agent such as decane; p-styryl trimethoate Styrene-based decane coupling agent such as decane; acrylate decane coupling agent such as 3-propenyloxypropyltrimethoxydecane and 3-methylpropenyloxypropyltrimethoxydecane; 3-isocyanate a sulfide-based decane coupler such as an isocyanate-based decane coupling agent such as propyltrimethoxydecane, bis(triethoxydecylpropyl)disulfide or bis(triethoxydecylpropyl)tetrasulfide Mixture; phenyltrimethoxydecane, methacryloxypropyltrimethoxydecane, imidazolium, triazine decane, and the like. These may be used alone or in combination of two or more.

The surface treatment of the component (F) can be carried out, for example, by adding a spray surface treatment agent while stirring and dispersing the untreated (F) component in a mixer at normal temperature, followed by stirring for 5 to 60 minutes. As the mixer, a known mixer can be used, and examples thereof include a mixer such as a V-type mixer, a belt mixer, a bubble mixer, a mixer such as a Henschel mixer and a concrete mixer, a ball mill, a grinder, and the like. Further, when the moisture absorbing material is pulverized by a ball mill or the like, the above-mentioned higher fatty acid, alkyl decane or decane coupling agent may be mixed and subjected to a surface treatment. The amount of the surface treatment agent to be treated differs depending on the type of the component (F) or the type of the surface treatment agent, and is preferably 1 to 10 parts by mass based on 100 parts by mass of the component (F).

The content of the component (F) in the curable resin composition of the present invention is not particularly limited, but the adhesion between the sealing layer composed of the cured product of the resin composition and the plastic substrate and the transparency of the sealing layer are In view of the total amount of the nonvolatile matter in the resin composition, the content is preferably 40% by mass or less, more preferably 35% by mass or less, still more preferably 30% by mass or less, and still more. Preferably, it is 25 mass% or less. In addition, the content is preferably 100% by mass or more, more preferably 0.1% by mass or more, and more preferably 0.5% by mass or more, based on the total amount of the nonvolatile matter in the resin composition, from the viewpoint of the effect of sufficiently obtaining the hygroscopicity. More preferably, it is 1.0% by mass or more.

Specific examples of the component (F) of the present invention include the following:
・DHT-4C (manufactured by Kyowa Chemical Industry Co., Ltd.): Semi-fired hydrotalcite (average particle diameter: 400 nm, BET specific surface area: 15 m ² /g)
・DHT-4A-2 (manufactured by Kyowa Chemical Industry Co., Ltd.): Semi-fired hydrotalcite (average particle diameter: 400 nm, BET specific surface area: 13 m ² /g)
・KW-2200 (made by Kyowa Chemical Industry Co., Ltd.): calcined hydrotalcite (average particle diameter: 400 nm, BET specific surface area: 146 m ² /g)
・DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.): unfired hydrotalcite (average particle diameter: 400 nm, BET specific surface area: 10 m ² /g)

<Other additives>
The curable resin composition of the present invention may further contain other additives different from the above components (E) and (F). Examples of such an additive include organic fillers such as rubber particles, silicone powders, nylon powders, and fluororesin powders; tackifiers such as ORBEN and Benton; polyfluorene oxides and fluorines; A defoaming agent or a leveling agent for a polymer or a polymer; a adhesion imparting agent such as a triazole compound, a thiazole compound, a triazine compound or a porphyrin compound; and the like.

<Method for Producing Curable Resin Composition>
The curable resin composition of the present invention is obtained by using a known mixer (components (A) to (D)) and, if necessary, components ((E), (F), etc.) by a known mixer. Or the disperser mixes to modulate. Examples of the agitator or dispersing machine include a dissolver, a planetary mixer, a rolling mill, a sand mill, a ball mill, a bead mill, a homogenizer, a high pressure homogenizer, a vacuum emulsifier (Aji homo mixer), and a rotation/revolution mixer. Wait.

The curable resin composition of the present invention is liquid at 25 ° C, preferably has a viscosity (25 ° C) of less than 300 mPas, more preferably 250 mPas or less. Although the lower limit is not particularly limited, it is preferably 10 mPas or more, and more preferably 20 mPas or more. Further, the "viscosity at 25 ° C" and "viscosity (25 ° C)" in the present invention mean "the viscosity at 25 ° C measured by a vibrating viscometer".

<Use>
The curable resin composition of the present invention is used for sealing various semiconductor elements and the like. Because of its high transparency, it is particularly suitable for sealing a photoelectric conversion element such as a light-emitting element such as an organic EL element or a light-receiving element such as a solar cell. Specifically, for example, a sealant for forming a sealing layer that protects the light-emitting portion of the organic EL element from the outside is used as an upper portion and/or a periphery (side portion) of the light-emitting portion of the organic EL element. Since the curable resin composition of the present invention is excellent in fluidity at room temperature, it can be directly applied to a sealing target, and a resin composition layer (coating layer) having the same properties can be easily formed. As the coating method, bar coating, blade coating, die coating, blade coating, dispenser, inkjet, or the like can be used alone or in combination. By curing the resin composition layer (coating layer) thus formed, a sealing layer having good transparency and sealing performance can be formed.

<hardened matter>
The curable resin composition of the present invention can be cured by light or heat. When it is cured by light, for example, a light of 1000 mJ/cm ² or more can be irradiated with a mercury lamp or the like. Further, when it is thermally cured, it can be cured by heating at a temperature of, for example, 60 to 150 °C. The cured product obtained by curing the curable resin composition of the present invention has an extremely small amount of exhaust gas generated, and can form a sealing layer which prevents deterioration of the element for a long period of time. In particular, even when the cured product is exposed to a high temperature of 100 ° C or higher, a sealing layer having a very small amount of exhaust gas generated and preventing deterioration of the element for a long period of time in a high temperature environment can be formed.

<Organic EL device>
In the sealing of the organic EL device, the sealing agent is applied in a frame shape on the substrate around the organic EL element, and the method of forming the substrate and the sealing substrate of the organic EL by the sealing agent (frame sealing method) is used, or A method of applying a sealant between the substrate on which the organic EL substrate is formed and the sealing substrate, and between the organic EL element and the sealing substrate, and hardening the method (surface sealing method).

Since the curable resin composition of the present invention has low viscosity at room temperature and high fluidity, it can be applied to a sealant of any sealing method, and a composition layer (coating layer) which can easily form the same property by coating a substrate ). When the composition layer (coating layer) is thermally cured to form a sealing layer, examples of the heating means include a hot air circulating oven, an infrared heater, a heat gun, a high frequency induction heating device, and heating by a heating tool. Wait. The individual lower limit of the hardening temperature and the hardening time can be obtained from the viewpoint that the cured object layer (sealing layer) of the hardened composition layer (coating layer) can be sufficiently cured by the sealing object. Preferably, it is 60 ° C or more, more preferably 80 ° C or more. The hardening time is preferably 15 minutes or longer, more preferably 30 minutes or longer. In this way, an organic EL device in which the organic EL element is sealed by the curable resin composition of the present invention can be obtained.

[Examples]

Hereinafter, the present invention will be more specifically described by way of examples, but the invention is not limited to the examples. In addition, in the following description, "%" and "parts" other than the reaction rate of the cured product mean "% by mass" and "parts by mass", respectively, unless otherwise stated.

The materials used in the examples and comparative examples are as follows.

(A) Ingredients and "CELLOXIDE 2021P" manufactured by Daicel Corporation
Compound having an alicyclic epoxy group (Compound name: 3', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (compound of formula (I-1)), molecular weight: 252.3 , epoxy equivalent: 128 ~ 145g / eq, viscosity (25 ° C): 100-600mPas)
・Synasia S-28 made by Synasia
A compound having an alicyclic epoxy group (Compound name: bis((3,4-epoxycyclohexyl)methyl) adipate) (compound of the formula (I-4)), molecular weight: 366, epoxy equivalent : 190 ~ 210g / eq, viscosity (25 ° C): 450-750mPas)

(B) Ingredients, "EHPE3150" (2,2-bis(hydroxymethyl)-1-butanol 1,2-epoxy-4-(2-oxiranyl)cyclohexane, manufactured by Daicel Corporation Additive, 2 functional or higher, weight average molecular weight: 2400)
・"1004" manufactured by Mitsubishi Chemical Corporation (bisphenol A type epoxy resin, 2-functional, weight average molecular weight: 1650)
・YX8040 manufactured by Mitsubishi Chemical Corporation (hydrogenated bisphenol A epoxy resin, 2-functional, weight average molecular weight: 3831)

(C) component: "CHDVE" (cyclohexane dimethanol divinyl ether, molecular weight 196.29) manufactured by Carbide Corporation, Japan
・DEGDVE, manufactured by Carbide, Japan (diethylene glycol divinyl ether, molecular weight 158.20)

(D) component: "CXC-1821" manufactured by King Industries Co., Ltd. (salt composed of a 4-grade ammonium cation and a borate anion, a thermal cationic polymerization initiator)

<Example 1>
55 parts of a bifunctional alicyclic epoxy resin ("CELLOXIDE 2021P" manufactured by Daicel Co., Ltd.) and 10 parts of a high molecular weight polyfunctional epoxy resin ("EHPE 3150" manufactured by Daicel Co., Ltd.) and a bifunctional divinyl group 35 parts of ether cyclohexane dimethanol divinyl ether ("CHDVE" manufactured by Japan Carbide Co., Ltd.) and 0.25 parts of a thermal cationic polymerization initiator ("CXC-1821" manufactured by King Industries Co., Ltd.), which are uniform in a high-speed rotary mixer. Disperse to obtain a composition.

<Examples 2 to 4>
The compositions of Examples 2 to 4 were obtained by uniformly dispersing the materials shown in Table 1 in the same manner as in Example 1 except that the materials used in Example 1 were changed to the blending ratios shown in Table 1.

<Example 5>
A composition was obtained in the same manner as in Example 1 except that "EHPE 3150" was changed to 10 parts of bisphenol A type epoxy resin "1004".

<Example 6>
A resin composition was obtained in the same manner as in Example 1 except that "EHPE 3150" was changed to 10 parts of hydrogenated bisphenol A type epoxy resin "YX8040".

<Example 7>
A resin composition was obtained in the same manner as in Example 1 except that "CHDVE" was changed to 35 parts of diethylene glycol divinyl ether ("DEGDVE").

<Example 8>
The same procedure as in the first embodiment was carried out except that 55 parts of "CELLOXIDE 2021P" were changed to 45 parts of "S-28" manufactured by Synasia Co., Ltd., and the amount of "EHPE 3150" was changed to 15 parts, and the amount of "CHDVE" was changed to 40 parts. A resin composition was obtained.

<Example 9>
60 parts of a bifunctional alicyclic epoxy resin ("CELLOXIDE 2021P" manufactured by Daicel Co., Ltd.), 20 parts of a high molecular weight polyfunctional epoxy resin ("EHPE 3150" manufactured by Daicel Co., Ltd.), and a 2-functional divinyl group 30 parts of ether cyclohexane dimethanol divinyl ether ("CHDVE" manufactured by Japan Carbide Co., Ltd.), and 5 parts of semi-calcined hydrotalcite ("DHT-4C" manufactured by Kyowa Chemical Industry Co., Ltd.), and initiation of thermal cationic polymerization A 0.25 part ("CXC-1821" manufactured by King Industries Co., Ltd.) was uniformly dispersed in a high-speed rotary mixer to obtain a composition.

<Comparative Example 1>
100 parts of a bifunctional alicyclic epoxy resin ("CELLOXIDE 2021P" manufactured by Daicel Co., Ltd.) and 0.25 parts of a thermal cationic polymerization initiator ("CXC-1821" manufactured by King Industries Co., Ltd.) were blended in a high-speed rotary mixer. Disperse to obtain a composition.

<Comparative Example 2>
50 parts of a high molecular weight polyfunctional epoxy resin ("EHPE 3150" manufactured by Daicel Corporation) and cyclohexanedimethanol divinyl ether (manufactured by Carbide Co., Ltd. "CHDVE") 50 as a bifunctional divinyl ether 0.25 parts by weight and thermal cationic polymerization initiator ("CXC-1821" manufactured by King Industries Co., Ltd.), and tried to disperse in a high-speed rotary mixer, but a high molecular weight polyfunctional epoxy resin ("EHPE3150" manufactured by Daicel Co., Ltd.) The composition was insoluble without being dissolved.

<Comparative Example 3>
Blending 50 parts of a bifunctional alicyclic epoxy resin ("CELLOXIDE 2021P") with 50 parts of cyclohexanedimethanol divinyl ether ("CHDVE") as a bifunctional divinyl ether, and thermally cationic polymerization 0.25 parts of a starter ("CXC-1821" manufactured by King Industries Co., Ltd.) was uniformly dispersed in a high-speed rotary mixer to obtain a composition.

<Comparative Example 4>
50 parts of a bifunctional alicyclic epoxy resin ("CELLOXIDE 2021P"), 50 parts of "EHPE3150" as a high molecular weight polyfunctional epoxy resin, and a thermal cationic polymerization initiator (CXC manufactured by King Industries Co., Ltd.) -1821") 0.25 parts were uniformly dispersed by a high-speed rotary mixer to obtain a composition.

The compositions prepared in the examples and the comparative examples were subjected to the following evaluation tests for the viscosity, the reaction rate, and the amount of exhaust gas. The results are shown in Table 1 below.

<Viscometry>
The composition prepared in the examples and the comparative examples was measured for viscosity at 25 ° C using a vibrating viscometer ("VM-10A" manufactured by Sekonic Co., Ltd.), and evaluated by the following criteria.
Excellent (◎): less than 100mPas
Good (○): 100mPas or more and less than 300mPas
(△): 300mPas or more and less than 500mPas
Bad (×): 500mPas or more or insoluble

<Reaction rate measurement>
The calorific value before and after the reaction in which the composition prepared in the examples and the comparative examples was heated at 100 ° C for 30 minutes was measured by a differential scanning calorimeter ("DSC7000X" manufactured by Hitachi, Ltd.), and the reaction rate was determined by the following formula. Calculated.
Reaction rate (%) of the composition = 100 × (1 - calorific value after hardening / calorific value before hardening)
The reaction rate was evaluated on the basis of the following criteria.
Good (○): 95% or more can be (△): 90% or more and less than 95%
Bad (×): less than 90%

<Measurement of exhaust volume>
The composition prepared in the examples and the comparative examples was heated at 100 ° C for 30 minutes to prepare a cured product, and the amount of exhaust gas heated at 100 ° C for 2 hours was measured by a differential thermogravimetric weight measuring device (manufactured by Hitachi High-Technologies Corporation). "STA7000") measurement.
The amount of exhaust gas is evaluated on the basis of the following criteria.
Excellent (◎): less than 100ppm
Good (○): 100ppm or more and less than 300ppm
(△): 300ppm or more and less than 500ppm
Bad (×): 500ppm or more

<Transmission rate measurement>
To the respective resin compositions prepared in Examples 1 to 9 and Comparative Examples 1 to 4, the resin was dropped in an appropriate amount on an alkali-free glass plate (length 50 mm, width 50 mm, thickness 700 μm, OA-10G manufactured by Nippon Electric Glass Co., Ltd.). After the composition, the mixture was immersed in an alkali-free glass of the same size and heated at 100 ° C for 30 minutes to prepare a sample for measurement of transmittance (thickness: 10 μm). Using a haze meter manufactured by Suga Test Instruments Co., Ltd., the air was used as a reference, and the total light transmittance of the sample for evaluation of D65 light was confirmed to be 90% or more, indicating high transparency.

In Table 1, the viscosity, reaction rate, and exhaust volume represent measured values and evaluation results.
From the results of Table 1, it was confirmed that the compositions of Examples 1 to 9 were all low in viscosity at room temperature, and had excellent coating suitability, and the reaction rate of the hardening reaction was high, and the cured product after the hardening reaction was placed even. At a high temperature, a sealing layer having a very small amount of exhaust gas generated and preventing deterioration of the element for a long period of time can be formed.

<Device Seal Test>
The sealing property using an organic EL element was evaluated. First, an organic EL device (thickness of organic film: 110 nm, thickness of cathode: 10 nm) was formed on a glass substrate (manufactured by GEOMATEC Co., Ltd.) with indium tin oxide (ITO) so that the light-emitting area was 4 mm ² . Next, a nitride film (thickness: 500 nm) was formed on the organic EL device by a chemical vapor deposition method (CVD method). Next, the composition prepared in Example 1 was dropped on the organic EL element with the nitride film, and the alkali-free glass plate was superposed thereon to prepare a laminate (alkali-free glass plate/composition layer/nitride film). Organic EL element / glass substrate with ITO). The composition was cured by heating the laminate at 100 ° C for 30 minutes to produce a laminate of a sealed organic EL element (thickness of the cured product: 10 μm). When a voltage was applied to the sealed organic EL element and the initial characteristics were evaluated, it was confirmed that good luminescence was exhibited, and the sealing layer was formed satisfactorily.

[Industrial availability]

In the curable resin composition for sealing of the present invention, a cured product having a very small amount of exhaust gas generated is obtained, and a sealing layer which prevents deterioration of the element for a long period of time can be obtained. Moreover, since the curable resin composition for sealing of the present invention is excellent in fluidity at room temperature, it can be directly applied to a sealing object, and a composition layer (coating layer) of the same property can be easily formed, and can be placed in a predetermined place. Form a high performance sealing layer.

This case is based on the Japanese Patent Application No. 2018-011571, the contents of which are all included in the present specification.

Claims (9)

A curable resin composition for sealing comprising (A) a 2-functional alicyclic epoxy resin having a molecular weight of less than 1,000, (B) a polyfunctional epoxy resin having a molecular weight of 1,000 or more, and (C) a 2-functional vinyl group An ether compound and (D) a cationic polymerization initiator. The curable resin composition for sealing according to claim 1, wherein the (B) polyfunctional epoxy resin has a molecular weight of 10,000 or less. The curable resin composition for sealing according to claim 1 or 2, wherein the (B) polyfunctional epoxy resin has a cyclic skeleton. The curable resin composition for sealing according to any one of claims 1 to 3, wherein the (C) bifunctional vinyl ether compound has a molecular weight of 1,000 or less. The curable resin composition for sealing according to any one of claims 1 to 4, wherein the viscosity at 25 ° C is less than 300 mPas. The curable resin composition for sealing according to any one of claims 1 to 5, wherein the (D) cationic polymerization initiator is a thermal cationic polymerization initiator. The curable resin composition for sealing according to any one of claims 1 to 6, wherein the (A) bifunctional alicyclic epoxy resin has a molecular weight of 100 or more. The sealing curable resin composition according to any one of claims 1 to 7, which is used for sealing an organic EL element. An organic EL device that seals an organic EL device with a cured product of the curable resin composition according to any one of claims 1 to 7.