JPWO2019146736A1 - Curable resin composition for sealing - Google Patents

Abstract

The present invention comprises (A) a bifunctional alicyclic epoxy resin having a molecular weight of less than 1000, (B) a polyfunctional epoxy resin having a molecular weight of 1000 or more, (C) a bifunctional vinyl ether compound, and (D) a cationic polymerization initiator. Provided is a curable resin composition for sealing, which comprises.

Description

The present invention relates to a curable resin composition for encapsulation, and more specifically, various semiconductor devices, particularly light emitting devices such as organic electroluminescence devices (hereinafter, also abbreviated as “organic EL devices”), light receiving elements such as solar cells, and the like. The present invention relates to a curable resin composition for sealing suitable for sealing a photoelectric conversion element of the above.

An organic EL element is a light emitting element that uses an organic substance as a light emitting material, and has been in the limelight in recent years because it can obtain high-luminance light emission at a low voltage. In order to improve the durability of the organic EL device, it is necessary to block the inside of the device from oxygen and moisture in the outside air. For example, a resin composition is used so as to cover the entire surface of the light emitting layer formed on the substrate. An organic EL element is sealed by forming a sealing layer.

Thermosetting or photocurable resin compositions are often used for this type of resin composition. For example, Patent Document 1 describes a low molecular weight polyfunctional epoxy resin and a high molecular weight monofunctional or high molecular weight. A photocurable resin composition containing a polyfunctional epoxy resin and a silane coupling agent containing a glycidyl group in the molecule has been proposed. Although such a resin composition has an advantage that the amount of outgas generated from the cured product is small, it has a drawback that it has low fluidity at room temperature due to its high viscosity and it is difficult to form a sealing layer having uniform properties.

Japanese Unexamined Patent Publication No. 2010-1266699

The present invention has been made in view of the above circumstances, and provides a curable resin composition for sealing, which can provide a cured product having excellent fluidity at room temperature and a small amount of outgas generated. The purpose is.
Another object of the present invention is to provide a curable resin composition for sealing, which is excellent in fluidity at room temperature, generates a small amount of outgas, and can give a cured product having high transparency.

As a result of diligent research to achieve the above object, the present inventors have determined to dissolve an epoxy resin having a molecular weight of a certain level or more in a mixture of a low molecular weight bifunctional alicyclic epoxy resin and a bifunctional vinyl ether compound. The present invention was completed by finding that a curable resin composition having a low viscosity before curing, excellent fluidity at room temperature, and by curing produces a cured product having high transparency and less generation of outgas. I came to do it.

That is, the present invention has the following features.
[1] Includes (A) a bifunctional alicyclic epoxy resin having a molecular weight of less than 1000, (B) a polyfunctional epoxy resin having a molecular weight of 1000 or more, (C) a bifunctional vinyl ether compound, and (D) a cationic polymerization initiator. , Curable resin composition for sealing.
[2] The curable resin composition for sealing according to the above [1], wherein the polyfunctional epoxy resin has a molecular weight of 10,000 or less.
[3] (B) The curable resin composition for sealing according to the above [1] or [2], wherein the polyfunctional epoxy resin has a cyclic skeleton.
[4] The curable resin composition for sealing according to any one of the above [1] to [3], wherein the (C) bifunctional vinyl ether compound has a molecular weight of 1000 or less.
[5] The curable resin composition for sealing according to any one of the above [1] to [4], which has a viscosity at 25 ° C. of less than 300 mPas.
[6] The curable resin composition for sealing according to any one of the above [1] to [5], wherein the cationic polymerization initiator is a thermosetting polymerization initiator.
[7] The curable resin composition for sealing according to any one of the above [1] to [6], wherein the 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 an organic EL element is sealed with a cured product of the curable resin composition for sealing according to any one of the above [1] to [7].

Since the curable resin composition of the present invention has low viscosity at room temperature and high fluidity, it is possible to easily form a composition layer (coating layer) having uniform properties by coating. Then, the cured product generates a small amount of outgas even when exposed to a high temperature, and can form a sealing layer that prevents deterioration of the device for a long period of time. Further, 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 according to its preferred embodiment. It should be noted that the examples and preferred descriptions described below can be combined as long as they do not contradict each other.
The curable resin composition of the present invention (hereinafter, also simply referred to as “resin composition”) is at least (A) a bifunctional alicyclic epoxy resin having a molecular weight of less than 1000, and (B) having a molecular weight of 1000 or more. Its main feature is that it contains a functional epoxy resin, (C) a bifunctional vinyl ether compound, and (D) a cationic polymerization initiator.

<(A) Bifunctional alicyclic epoxy resin with a molecular weight of less than 1000>
The curable resin composition of the present invention contains (A) a bifunctional alicyclic epoxy resin having a molecular weight of less than 1000 (hereinafter, also referred to as “component (A)”). The component (A) is not particularly limited as long as it is a compound having two alicyclic epoxy groups in one molecule and having a molecular weight of less than 1000. The "aliphatic epoxy group" is a group in which two adjacent carbon atoms constituting the alicyclic of the alicyclic group form an oxylan ring (epoxide group) with an oxygen atom. For example, an epoxycyclopentyl group. , Epoxide cyclohexyl group and the like, preferably an epoxycyclohexyl group. The component (A) may have an alicyclic condensed alicyclic structure in which a plurality of alicyclic epoxy groups are condensed at the alicyclic portion.

The component (A) is preferably of the formula (I) :.

[In 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, an amide bond, or a group in which a plurality of these are linked]
It is a compound represented by.

In the compound represented by the formula (I), the divalent hydrocarbon group exemplified as the linking group includes a linear or branched alkylene group having 1 to 18 carbon atoms and a divalent alicyclic group. Hydrocarbon groups (particularly divalent cycloalkylene groups) and the like are preferably exemplified. Examples of the linear or branched alkylene group having 1 to 18 carbon atoms include methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene group. Examples of the divalent alicyclic hydrocarbon group include 1,2-cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1, Examples thereof include a divalent cycloalkylene group (including a cycloalkylidene group) such as 4-cyclohexylene and a cyclohexylidene group.

Typical 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.

As the compound represented by the formula (I), a commercially available product can be used, for example, "Selokiside 2021P", "Selokiside 2081", "Selokiside 8000" (all manufactured by Daicel), "Synasia S-21E". , "Synasia S-28", "Synasia S-60" (hereinafter, manufactured by Synasia), "TTA60", "TTA2081", "TTA2083" (hereinafter, manufactured by Tetrachem) and the like.

In the present invention, the component (A) has a molecular weight of less than 1000, preferably 900 or less, more preferably 800 or less, further preferably 700 or less, and further preferably 600, from the viewpoint of fluidity of the curable resin composition at room temperature. The following are particularly preferred. The lower limit of the molecular weight is not particularly limited, but from the viewpoint of suppressing the generation of outgas, 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 10 to 1000 mPas, more preferably 25 to 750 mPas, from the viewpoint of fluidity of the curable resin composition at room temperature. The "viscosity at 25 ° C." and "viscosity (25 ° C.)" in the present invention both mean "viscosity at 25 ° C. measured using a vibration viscometer".

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

In the present invention, one kind or two or more kinds 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, more preferably 45% by mass or more, based on the total non-volatile content of the curable resin composition from the viewpoint of heat resistance. Further, from the viewpoint of reactivity at the time of curing, 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, based on the total non-volatile content.

<(B) Polyfunctional epoxy resin with a molecular weight of 1000 or more>
The curable resin composition of the present invention contains (B) a polyfunctional epoxy resin having a molecular weight of 1000 or more (hereinafter, also abbreviated as “component (B)”). The component (B) is not particularly limited as long as it has an average of two or more epoxy groups per molecule and has a molecular weight of 1000 or more. In the present specification, when the component in the resin composition is a polymer, its molecular weight means "weight average molecular weight".
Here, the weight average molecular weight is measured by a gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the weight average molecular weight by the GPC method is measured by moving the LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device and the polystyrene K-800P / K-804L / K-804L manufactured by Showa Denko Co., Ltd. as a column. It can be measured using chloroform or the like as a phase at a column temperature of 40 ° C. and calculated using a standard polystyrene calibration curve.

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

(B1) As the aromatic epoxy resin, bisphenol A type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, fragrance Group glycidylamine type epoxy resin (for example, tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyl toluidine, diglycidylaniline, etc.), phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin , Diglycidyl etherified product of bisphenol, diglycidyl etherified product of naphthalene diol, diglycidyl etherified product of phenols, alkyl substitutes of these epoxy resins, halides and the like. Of these, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferable from the viewpoint of transparency. Examples of the aromatic epoxy resin include "1004" which is a bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent: 875-975 g / eq, weight average molecular weight: 1650) and "4004P" which is a bisphenol F type epoxy resin. (Manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent: 840 to 975 g / eq, weight average molecular weight: 1815) and the like.

Examples of the epoxy resin having (B2) an alicyclic skeleton include (i) a compound having an alicyclic epoxy group, (ii) a compound in which an epoxy group is directly bonded to the alicyclic with a single bond, and (iii) an alicyclic. Examples thereof include compounds having a structure in which a glycidyl ether skeleton and / or a diglycidyl amine skeleton is directly linked.

Examples of the compound (i) 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 is a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, an s-butylene group, a pentylene group, or a hexylene. Examples thereof include a linear or branched alkylene group such as a group, a heptylene group, and an octylene group. L in the following formula (b-1) represents an integer of 6 to 30, and m in the following formula (b-2). Indicates an integer of 7 to 30, n1 and n2 in the following formula (b-3) each indicate an integer of 2 to 30, and n3 to n6 in (b-4) indicate an integer of 1 to 30, respectively. ..

Examples of the compound in which the epoxy group is directly bonded to the alicyclic (ii) by a single bond include a compound represented by the following formula (II).

In formula (II), R'is a group obtained by subtracting p -OH from a p-valent alcohol, and p and n each represent a natural number. Examples of the p-valent alcohol [R'-(OH) _p ] include polyhydric alcohols such as 2,2-bis (hydroxymethyl) -1-butanol (alcohols having 1 to 15 carbon atoms). p is preferably 1 to 6, and n is preferably 1 to 30. When p is 1, n is 2 or more, and when p is 2 or more, n in each group in parentheses (in parentheses) may be the same or different. Specific examples of the above compound include 1,2-epoxy-4- (2-oxylanyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol (trade name "EHPE3150", manufactured by Daicel Corporation). ) Etc. can be mentioned.

(Iii) Examples of the compound having a structure in which the glycidyl ether skeleton and / or the diglycidyl amine skeleton are directly linked to the alicyclic include a hydrogenated bisphenol A type epoxy resin, a hydrogenated bisphenol F type epoxy resin, and a dicyclopentadiene type epoxy resin. And so on. In addition, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, aromatic glycidylamine type epoxy resin (for example, tetraglycidyldiaminodiphenylmethane, Triglycidyl-p-aminophenol, diglycidyl toluidine, diglycidyl aniline, etc.), phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol diglycidyl etherified product, naphthalenediol diglycidyl ether Examples thereof include an epoxy resin in which the aromatic ring of an aromatic epoxy resin such as a compound or a diglycidyl ether compound of phenols is converted into an alicyclic by hydrogenation. Of these, hydrogenated bisphenol A type epoxy resin and hydrogenated bisphenol F type epoxy resin are preferable from the viewpoint of transparency. Specific examples of the compound include hydrogenated bisphenol A type epoxy resin "YX-8040" (manufactured by Mitsubishi Chemical Corporation), epoxy equivalent: 1000 g / eq, weight average molecular weight: 3831) and the like.

The component (B) has a molecular weight (weight average molecular weight) of 1000 or more, preferably 1500 or more, from the viewpoint of suppressing the amount of outgas 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, preferably 5,000 or less, from the viewpoint of the fluidity of the curable resin composition at room temperature. Is more preferable.

The epoxy equivalent of the component (B) is preferably 50 to 3000 g / eq, more preferably 80 to 2000 g / eq, and more preferably 100 to 1500 g / eq from the viewpoint of reactivity and the like. In the present specification, "epoxy equivalent" is the number of grams (g / eq) of a resin containing 1 gram equivalent of an epoxy group, and is measured according to 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, "liquid" and "solid" are states of the epoxy resin at room temperature (25 ° C.).

As the component (B), a commercially available product can be used, and as the (B1) aromatic epoxy resin, for example, "1004" (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 875-975 g / eq) which is a bisphenol A type epoxy resin. , Weight average molecular weight: 1650) and the like. Further, as the epoxy resin having the (B2) alicyclic skeleton, "EHPE3150" (manufactured by Daicel Co., Ltd., compound name: 2,2-bis (hydroxymethyl) -1-butanol 1,2-epoxy-4- ( 2-Oxylanyl) cyclohexane adduct, epoxy equivalent: 70-190 g / eq, weight average molecular weight: 2400), hydrogenated bisphenol A type 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 kind 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, preferably 5% by mass, based on the total non-volatile content of the curable resin composition, from the viewpoint of effectively suppressing the amount of outgas generated. % Or more is more preferable. Further, from the viewpoint of maintaining fluidity at room temperature, the curable resin composition is preferably 30% by mass or less, more preferably 25% by mass or less, based on the total non-volatile content.

<(C) Bifunctional vinyl ether compound>
The curable resin composition of the present invention contains a bifunctional vinyl ether compound (hereinafter, also referred to as “component (C)”). The component (C) can be used without particular limitation as long as it is a compound having two vinyl ether groups in one molecule.

More specifically, the component (C) includes 1,4-butanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, cyclohexanedimethanol divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, and polyethylene glycol divinyl ether. , Propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, 1,8-octanediol divinyl ether, 1,9-nonanediol divinyl ether, trimethylpropandivinyl ether, bisphenol A divinyl ether, bisphenol F divinyl ether, Examples thereof include 3,3-bis (vinyloxymethyl) oxetane and isosorbide divinyl ether. Of these, cyclohexanedimethanol divinyl ether and diethylene glycol divinyl ether are preferable.
As the component (C), a commercially available product can be used, which is a cyclohexanedimethanol divinyl ether "CHDVE" (manufactured by Nippon Carbide, molecular weight 196.29) and a diethylene glycol divinyl ether "DEGDVE" (manufactured by Nippon Carbide, Inc., The molecular weight is 158.20) and the like.

The component (C) preferably has a molecular weight of 1000 or less, more preferably 500 or less, and even more preferably 400 or less.

In the present invention, one kind 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% by mass or more based on the total non-volatile content of the curable resin composition from the viewpoint of maintaining the fluidity of the curable resin composition at room temperature. , 25% by mass or more is more preferable. Further, from the viewpoint of suppressing outgas, 50% by mass or less is preferable, and 45% by mass or less is more preferable, based on the total non-volatile content of the curable resin composition.

<(D) Cationic polymerization initiator>
The curable resin composition of the present invention contains a cationic polymerization initiator (hereinafter, also referred to as “component (D)”). 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) to act on the component (A), the component (B), and the component (C). As long as it can initiate each of the cationic polymerization reactions of the above, it may be a photocationic polymerization initiator or a thermal cationic polymerization initiator. That is, the curable resin composition of the present invention may be a photocurable resin composition or a thermosetting resin composition.

The photocationic polymerization initiator is also called a photoacid generator, a photocuring agent or a photocationic generator, and has a substantial function as a curing agent by irradiation with ultraviolet rays (component (A), component (B), and (C). ) The function of polymerizing the components) is exhibited.

Examples of the photocationic polymerization initiator include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, p- (phenylthio) phenyldiphenylsulfonium hexafluoroantimonate, p- (phenylthio) phenyldiphenylsulfonium hexafluorophosphate, and the like. 4-Chrolphenyl diphenyl sulfonium hexafluorophosphate, 4-chlorophenyl diphenyl sulfonium hexafluoroantimonate, bis [4- (diphenyl sulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (diphenyl sulfonio) phenyl ] Sulfide bishexafluoroantimonate, (2,4-cyclopentadiene-1-yl) [(1-methylethyl) benzene] -Fe-hexafluorophosphate, diallyl iodonium hexafluoroantimonate and the like. As these photocationic polymerization initiators, one kind or two or more kinds can be used.

In the present invention, the thermal cationic polymerization initiator is more advantageous than the photocationic polymerization initiator because it can seal the surface of the organic EL device without irradiating it with light, and is preferably used. The thermal cation polymerization initiator is also called a thermoacid generator, a thermosetting agent or a thermocation generator, and when it reaches the curing temperature, it has a substantial function as a curing agent (component (A), component (B) and ( C) It exerts a function of polymerizing components).

The thermal cationic polymerization initiator is not particularly limited, but an organic onium salt compound in which a cationic component and an anionic component are paired is preferable. Examples of the cation component include organic sulfonium, organic oxonium, organic ammonium, organic phosphonium, and organic iodonium. As examples of the anion component, ^{_{e.g., 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 ⁻ , (CF ₃ SO ₂ ) ₃ C ^{− and the} like can be mentioned. Commercially available products of the thermal cationic polymerization initiator include, for example, TA-60, TA-60B, TA-100, TA-120, TA-160 (all manufactured by San-Apro), K-PURE (registered trademark) TAG-. 2678, TAG-2681, TAG-2689, TAG-2690, TAG-2700, CXC-1612, CXC-1614, CXC-1615, CXC-1616, CXC-1733, CXC- 1738, CXC-1742, CXC-1802, CXC-1821 (all manufactured by King Industries), Sun Aid SI-45, SI-45L, SI-60, SI-60L, SI-80, SI-80L, SI-100, SI-100L, SI-110, SI-110L, SI-150, SI-150L, SI-180, SI-180L, SI-B2, SI-B2A, SI-B3, SI-B3A, SI-B4, SI-B5, SI-200, SI-210, SI-220, SI-300, SI-360 ( As mentioned above, (manufactured by Sanshin Chemical Industry Co., Ltd.) can be mentioned.

Among them, preferred are salts having quaternary ammonium cation, more preferably a quaternary ammonium cation and a borate anion ^{_{(BF 4 -, B (C}} 6 F 5) 4 - , etc.) salt comprising a quaternary ammonium cation and antimony anions ( ^{_{SbF 4 -, Sb (C 6}} F 5) 4 - is a salt comprising etc.), particularly preferably a quaternary ammonium cation and a borate anion consisting ^{_{etc.) - (BF 4 -, B}} (C 6 F 5) 4 It is salt.

Quaternary ammonium cation and a borate anion ^{_{(BF 4 -, B (C}} 6 F 5) 4 - , etc.) Specific examples of a salt, for example, dimethylphenyl (4-methoxybenzyl) ammonium tetrakis (pentafluorophenyl) borate , Dimethylphenyl (4-methylbenzyl) ammonium hexafluorotetrakis (pentafluorophenyl) borate, methylphenyldibenzylammonium tetrakis (pentafluorophenyl) borate, phenyltribenzylammonium tetrakis (pentafluorophenyl) borate, dimethylphenyl (3, Examples thereof include 4-dimethylbenzyl) ammonium tetrakis (pentafluorophenyl) borate, N, N-diethyl-N-benzylanilinium tetrafluoride.

In the present invention, one kind 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, preferably 0.1 to 2.5% by mass, based on the total non-volatile content of the curable resin composition. More preferably by mass.

When the component (D) is a thermal cationic polymerization initiator, one capable of exhibiting a substantial function as a curing agent at a relatively low temperature is preferable. Specifically, those capable of exhibiting a substantial function as a curing agent at 150 ° C. or lower are preferable. As a result, when the substrate having the element or the sealing substrate is made of a resin material having low heat resistance, the influence on the substrate due to heating in the thermosetting step and the thermal deterioration of the element can be reduced. A more preferable temperature for exhibiting a substantial function as a curing agent is 120 ° C. or lower.

The curable resin composition of the present invention is a composition containing at least the above-mentioned components (A) to (D), and is preferably a composition comprising the above-mentioned components (A) to (D). .. The following components ((E) thermoplastic resin, (F) hygroscopic filler, etc.) can be blended as needed.

<(E) Thermoplastic resin>
The curable resin composition of the present invention includes (E) a thermoplastic resin from the viewpoints of imparting flexibility to the sealing layer, which is a cured product, and coating properties (preventing repelling) of the curable resin composition. (Hereinafter, also referred to as “(E) component)”) can be contained. Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, polyimide resin, polyamideimide resin, polyethersulfone resin, polysulfone resin, polyester resin, (meth) acrylic polymer and the like. Only one type of these thermoplastic resins may be used, or two or more types may be used in combination.

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

As the component (E), a phenoxy resin is particularly preferable. The phenoxy resin has good compatibility with a thermosetting resin (particularly an epoxy resin), and has an advantageous effect on the water-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, and more preferably 800,000 or less.

Suitable phenoxy resins include one or more skeletons selected from bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, and norbornene skeleton. What you have. One type or two or more types of phenoxy resin can be used.

Examples of commercially available phenoxy resins include 1256 (bisphenol A skeleton-containing phenoxy resin) and 4275 (bisphenol A skeleton-containing phenoxy resin) manufactured by Mitsubishi Chemical Corporation.

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

<(F) Hygroscopic filler>
The curable resin composition of the present invention has a hygroscopic filler (hereinafter, also abbreviated as “component (F)”) in order to impart higher water vapor permeability to the sealing layer which is a cured product. Can be blended. The hygroscopic filler (F) is not particularly limited as long as it is a filler having an ability to absorb water, but is preferably a hygroscopic metal oxide. A hygroscopic metal oxide means a metal oxide having an ability to absorb water and chemically reacting with the absorbed water to become a hydroxide. Specific examples thereof include calcium oxide, magnesium oxide, strontium oxide, aluminum oxide, barium oxide, uncalcined hydrotalcite, semi-calcined hydrotalcite, calcined hydrotalcite, and calcined dolomite. Of these, semi-calcined hydrotalcite and calcined hydrotalcite are preferable from the viewpoint of hygroscopicity.

Hydrotalcite can be classified into uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite.

Unfired hydrotalcite is, for example, a metal hydroxide having a layered crystal structure typified by natural hydrotalcite _{(Mg 6 Al 2 (OH)} 16 CO 3 · 4H 2 O), for example, It consists of a basic skeleton layer [Mg _1-X Al _X (OH) ₂ ] ^{X +} and an intermediate layer [(CO ₃ ) _{X / 2} · mH ₂ O] ^X− . The uncalcined hydrotalcite in the present invention is a concept including hydrotalcite-like compounds such as synthetic hydrotalcite. Examples of the hydrotalcite-like compound include those represented by the following formulas (I) and (II).

^{_{[M 2+ 1-x M 3+}} x (OH) 2] x + · [(A n-) x / n · mH 2 O] x- (I)
^{(Wherein, M 2+} is ^Mg 2+, a divalent metal ion such as ^{Zn 2+, M 3+} represents a trivalent metal ion such as ^{Al 3+, Fe} 3+, ^{A n-} is _CO ³ 2-, Cl ^-, NO ₃ ^- represents a n-valent anion, such as a 0 <x <1, a 0 ≦ m <1, n is a positive number).
Wherein ^{(I), M 2+} is preferably ^{Mg 2+, M 3+} is preferably ^{Al 3+, A n-is} preferably _CO ^{3 2-.}

^{_{M 2+ x Al 2 (OH)}} 2x + 6-nz (A n-) z · mH 2 O (II)
^{(Wherein, M 2+} is ^Mg 2+, a divalent metal ion such as ^{Zn 2+, A n-} is _CO ^{3 2-,} Cl ^-, represents an n-valent anion such as ^{NO 3-,} x is 2 or more Is a positive number, z is a positive number less than or equal to 2, m is a positive number, and n is a positive number.)
Wherein ^{(II), M 2+} is preferably ^{Mg 2+, A n-is} preferably _CO ^{3 2-.}

Semi-calcined hydrotalcite refers to a metal hydroxide having a layered crystal structure in which the amount of interlayer water is reduced or eliminated, which is obtained by calcining uncalcined hydrotalcite. The term "interlayer water" refers to "H ₂ O" described in the above-mentioned composition formulas of uncalcined natural hydrotalcite and hydrotalcite-like compounds, if it is described using a composition formula.

On the other hand, calcined hydrotalcite refers to a metal oxide having an amorphous structure obtained by calcining uncalcined hydrotalcite or semi-calcined hydrotalcite, in which not only interlayer water but also hydroxyl groups are eliminated by condensation dehydration.

Uncalcined hydrotalcite, semi-calcined hydrotalcite and calcined hydrotalcite can be distinguished by the saturated water absorption rate. The saturated water absorption rate 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 rate of uncalcined hydrotalcite is less than 1% by mass, and the saturated water absorption rate of calcined hydrotalcite is 20% by mass or more.

The "saturated water absorption rate" as used herein means that 1.5 g of unfired hydrotalcite, semi-fired hydrotalcite or calcined hydrotalcite is weighed with a balance, the initial mass is measured, and then the temperature is 60 ° C. , The mass increase rate with respect to the initial mass when left to stand for 200 hours in a small environmental tester (SH-222 manufactured by Espec Co., Ltd.) set to 90% RH (relative humidity).
Saturated water absorption rate (mass%)
= 100 × (mass after moisture absorption-initial mass) / initial mass (i)
Can be obtained at.

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

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

For thermogravimetric analysis, 5 mg of hydrotalcite was weighed in an aluminum sample pan using TG / DTA EXSTAR6300 manufactured by Hitachi High-Tech Science, and the nitrogen flow rate was 200 mL / min in an open state without a lid. It can be carried out from 30 ° C. to 550 ° C. under the condition of a heating rate of 10 ° C./min. The thermogravimetric reduction rate is calculated by the following formula (ii):
Thermogravimetric reduction rate (mass%)
= 100 × (mass before heating-mass when a predetermined temperature is reached) / mass before heating (ii)
Can be obtained at.

In addition, uncalcined hydrotalcite, semi-calcined hydrotalcite and calcined hydrotalcite can be distinguished by the peak and relative intensity ratio measured by powder X-ray diffraction. The semi-baked hydrotalcite shows a peak in which 2θ is split into two in the vicinity of 8 to 18 ° by powder X-ray diffraction, or a peak having a shoulder due to the combination of the two peaks, and the peak or shoulder appearing on the low angle side. The relative intensity ratio (low-angle side diffraction intensity / high-angle side diffraction intensity) of the diffraction intensity (= low-angle side diffraction intensity) and the diffraction intensity of the peak or shoulder appearing on the high-angle side (= high-angle side diffraction intensity) is 0.001. ~ 1,000. On the other hand, uncalcined hydrotalcite has only one peak near 8 to 18 °, or the relative intensity ratio of the diffraction intensity of the peak or shoulder appearing on the low angle side and the peak or shoulder appearing on the high angle side is in the above range. Be outside. The calcined hydrotalcite does not have a characteristic peak in the region of 8 ° to 18 °, but has a characteristic peak in 43 °. Powder X-ray diffraction measurement is performed by a powder X-ray diffractometer (PANalytical, Empyrean) with anti-cathode CuKα (1.5405 Å), voltage: 45 V, current: 40 mA, sampling width: 0.0260 °, scanning speed: 0. The measurement was performed under the conditions of .0657 ° / s and the measurement diffraction angle range (2θ): 5.0131 to 79.9711 °. The peak search uses the peak search function of the software attached to the diffractometer, and "minimum significance: 0.50, minimum peak tip: 0.01 °, maximum peak tip: 1.00 °, peak base width: 2". It can be performed under the condition of "0.00 °, method: minimum value of second derivative".

BET specific surface area of the semi-sintered hydrotalcite is preferably ^{1~250m 2 / g, 5~200m 2 /} g is more preferable. The BET specific surface area of semi-calcined hydrotalcite is calculated by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device (Macsorb HM Model 1210 Mountec) according to the BET method and using the BET multipoint method. Can be done.

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

As the component (F), one that has been surface-treated with a surface treatment agent can be used. As the surface treatment agent used for the surface treatment, for example, higher fatty acids, alkylsilanes, silane coupling agents and the like can be used, and among them, higher fatty acids and alkylsilanes are preferable. As the surface treatment agent, one kind or two or more kinds can be used.

Examples of the higher fatty acid include higher fatty acids having 18 or more carbon atoms such as stearic acid, montanic acid, myristic acid, and palmitic acid, and stearic acid is preferable. These may be used alone or in combination of two or more. Examples of alkylsilanes include methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, dimethyldimethoxysilane, octyltriethoxysilane, and n-octadecyldimethyl (n-octadecyldimethyl). Examples thereof include 3- (trimethoxysilyl) propyl) ammonium chloride. These may be used alone or in combination of two or more. Examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyl (dimethoxy) methylsilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxy. Epoxy silane coupling agents such as silane; mercapto silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane and 11-mercaptoundecyltrimethoxysilane 3-Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, N-phenyl-3-aminopropyltrimethoxysilane, N-methylaminopropyltrimethoxysilane, N- (2) Amino-based silane coupling agents such as −aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropyldimethoxymethylsilane; ureido-based silanes such as 3-ureidopropyltriethoxysilane Coupling agents, vinyl-based silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane and vinylmethyldiethoxysilane; styryl-based silane coupling agents such as p-styryltrimethoxysilane; 3-acrylicoxypropyltrimethoxy Acrylic silane coupling agents such as silane and 3-methacryloxypropyltrimethoxysilane; isocyanate-based silane coupling agents such as 3-isocyanpropyltrimethoxysilane, bis (triethoxysilylpropyl) disulfide, bis (triethoxysilylpropyl) ) A sulfide-based silane coupling agent such as tetrasulfide; phenyltrimethoxysilane, methacryloxypropyltrimethoxysilane, imidazole silane, triazinesilane and the like can be mentioned. 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 stirring and dispersing the untreated component (F) at room temperature with a mixer, adding and spraying a surface treatment agent, and stirring for 5 to 60 minutes. .. As the mixer, a known mixer can be used, and examples thereof include blenders such as V blenders, ribbon blenders and bubble cone blenders, mixers such as Henshell mixers and concrete mixers, ball mills and cutter mills. Further, when pulverizing the moisture absorbing material with a ball mill or the like, a method of mixing the above-mentioned higher fatty acid, alkylsilanes or silane coupling agent and surface-treating the material is also possible. The treatment amount of the surface treatment agent varies depending on the type of the component (F), the type of the surface treatment agent, and the like, but is preferably 1 to 10 parts by mass with respect to 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 from the viewpoint of adhesion between the sealing layer made of the cured product of the resin composition and the plastic substrate and the transparency of the sealing layer. Therefore, the content is preferably 40% by mass or less, preferably 35% by mass or less, more preferably 30% by mass or less, still more preferably 25% by mass or less, based on 100% by mass of the total non-volatile content in the resin composition. .. Further, from the viewpoint of sufficiently obtaining a hygroscopic effect, the content is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on 100% by mass of the total non-volatile content in the resin composition. , 1.0% by mass or more is more preferable.

Specific examples of the component (F) in the present invention include the following:
-DHT-4C (manufactured by Kyowa Chemical Industry Co., Ltd.): Semi-calcined hydrotalcite (average particle size: 400 nm, BET specific surface area: 15 m ² / g)
-DHT-4A-2 (manufactured by Kyowa Chemical Industry Co., Ltd.): Semi-calcined hydrotalcite (average particle size: 400 nm, BET specific surface area: 13 m ² / g)
-KW-2200 (manufactured by Kyowa Chemical Industry Co., Ltd.): calcined hydrotalcite (average particle size: 400 nm, BET specific surface area: 146 m ² / g)
-DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.): Unfired hydrotalcite (average particle size: 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-mentioned component (E) and component (F). Examples of such additives include organic fillers such as rubber particles, silicone powder, nylon powder, and fluororesin powder; thickeners such as Orben and Benton; silicone-based, fluorine-based, and polymer-based defoamers. Alternatively, a leveling agent; an adhesion imparting agent such as a triazole compound, a thiazole compound, a triazine compound, and a porphyrin compound; and the like can be mentioned.

<Manufacturing method of curable resin composition>
In the curable resin composition of the present invention, essential components (components (A) to (D)) and components to be blended as necessary (components (E), (F), etc.) are mixed by a known stirrer or disperser. Prepared by mixing. Examples of the stirrer and disperser include a dissolver, a planetary mixer, a roll mill, a sand mill, a ball mill, a bead mill, a homogenizer, a high-pressure homogenizer, an azihomo mixer, and a rotation / revolution mixer.

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

<Use>
The curable resin composition of the present invention is used for sealing various semiconductor elements and the like. Since it has high transparency, it is particularly suitable for sealing a light emitting element such as an organic EL element or a photoelectric conversion element such as a light receiving element such as a solar cell. Specifically, for example, it is used as a sealing agent that is applied to the upper part and / or the periphery (side part) of the light emitting part of the organic EL element to form a sealing layer that protects the light emitting part of the organic EL element from the outside. .. Since the curable resin composition of the present invention has excellent fluidity at room temperature, it can be directly applied to the object to be sealed, and a resin composition layer (coating layer) having uniform properties can be easily formed. .. As the coating method, bar coat, comma coat, die coat, blade coat, dispenser, inkjet and 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.

<Cured product>
The curable resin composition of the present invention can be cured by light or heat. When cured by light, for example, light irradiation of 1000 mJ / cm ² or more can be performed with a mercury lamp or the like. When it is cured by heat, it can be cured by heating at, for example, a temperature of 60 to 150 ° C. The cured product obtained by curing the curable resin composition of the present invention produces an extremely small amount of outgas, and can form a sealing layer that prevents deterioration of the device over a long period of time. In particular, even if the cured product is exposed to a high temperature of 100 ° C. or higher, the amount of outgas generated is extremely small, and a sealing layer that prevents deterioration of the device for a long period of time in a high temperature environment can be formed.

<Organic EL device>
To seal the organic EL device, a sealing agent is applied in a frame shape to the substrate around the organic EL element, and the substrate on which the organic EL is formed and the sealing substrate are bonded to each other by the sealing agent (a method). Frame sealing method), or a method of applying a sealing agent between the substrate and the sealing substrate on which the organic EL is formed and between the organic EL element and the sealing substrate and curing it (surface). There is a 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 sealing agent in any sealing method, and a composition layer having uniform properties by coating on a substrate. (Coating layer) can be easily formed. When the composition layer (coating layer) is thermoset to form a sealing layer, the heating means includes, for example, a hot air circulation oven, an infrared heater, a heat gun, a high frequency induction heating device, and heating by crimping a heat tool. Can be mentioned. The lower limit of each of the curing temperature and the curing time is the curing temperature from the viewpoint that the cured product layer (sealing layer) obtained by curing the composition layer (coating layer) adheres to the object to be sealed with a sufficiently satisfactory adhesive strength. Is preferably 60 ° C. or higher, more preferably 80 ° C. or higher. The curing time is preferably 15 minutes or more, more preferably 30 minutes or more. In this way, it is possible to obtain an organic EL device in which the organic EL element is sealed with the curable resin composition of the present invention.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In the following description, unless otherwise specified, “%” and “parts” other than the reaction rate of the cured product mean “% by mass” and “parts by mass”, respectively.

The materials used in the examples and comparative examples are as follows.
(A) Ingredients-Daicel's "Selokiside 2021P"
Compound having an alicyclic epoxy group (compound name: 3', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (compound of formula (I-1)), molecular weight: 252.3, epoxy equivalent: 128 to 145 g / eq, viscosity (25 ° C.): 100-600 mPas)
-Synasia "Synasia S-28"
Compound having an alicyclic epoxy group (compound name: bis ((3,4-epoxycyclohexyl) methyl) adipate) (compound of formula (I-4)), molecular weight: 366, epoxy equivalent: 190-210 g / eq, viscosity (25 ° C): 450-750 mPas)

Ingredients (B) -Daicel's "EHPE3150" (1,2-epoxy-4- (2-oxylanyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol, bifunctional or higher, weight average molecular weight : 2400)
-Mitsubishi Chemical Corporation "1004" (bisphenol A type epoxy resin, bifunctional, weight average molecular weight: 1650)
-Mitsubishi Chemical Corporation "YX8040" (hydrogenated bisphenol A type epoxy resin, bifunctional, weight average molecular weight: 3831)
(C) Ingredients- "CHDVE" manufactured by Nippon Carbide Co., Ltd. (Cyclohexanedimethanol divinyl ether, molecular weight 196.29)
-"DEGDVE" manufactured by Nippon Carbide (diethylene glycol divinyl ether, molecular weight 158.20)
(D) Ingredients- "CXC-1821" manufactured by King Industries (a salt composed of a quaternary ammonium cation and a borate anion, a thermal cation polymerization initiator)

<Example 1>
55 parts of bifunctional alicyclic epoxy resin (“Selokiside 2021P” manufactured by Daicel), 10 parts of high molecular weight polyfunctional epoxy resin (“EHPE3150” manufactured by Daicel), and cyclohexanedimethanol divinyl ether (Japan) as bifunctional divinyl ether. 35 parts of "CHDVE" manufactured by Carbide and 0.25 part of a thermal cationic polymerization initiator ("CXC-1821" manufactured by King Industries) were mixed and uniformly dispersed with a high-speed rotating mixer to obtain a composition. It was.

<Examples 2 to 4>
Each material used in Example 1 was changed to the compounding ratio shown in Table 1 and uniformly dispersed in the same manner as in Example 1 to obtain the compositions of Examples 2 to 4.

<Example 5>
A composition was obtained in the same manner as in Example 1 except that "EHPE3150" 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 "EHPE3150" 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 as in Example 1 except that 55 parts of "Selokiside 2021P" were changed to 45 parts of "S-28" manufactured by Synasia, and the amount of "EHPE3150" 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 bifunctional alicyclic epoxy resin (“Selokiside 2021P” manufactured by Daicel), 20 parts of high molecular weight polyfunctional epoxy resin (“EHPE3150” manufactured by Daicel), and cyclohexanedimethanol divinyl ether (Japan) as bifunctional divinyl ether. 30 parts of "CHDVE" manufactured by Carbide, 5 parts of semi-baked hydrotalcite ("DHT-4C" manufactured by Kyowa Chemical Industry Co., Ltd.), and a thermal cationic polymerization initiator ("CXC-1821" manufactured by King Industries) 0. 25 parts were blended and uniformly dispersed with a high-speed rotary mixer to obtain a composition.

<Comparative example 1>
100 parts of a bifunctional alicyclic epoxy resin (Daicel's "Celoxide 2021P") and 0.25 part of a thermal cationic polymerization initiator (King Industries'"CXC-1821") are blended and uniform with a high-speed rotary mixer. The composition was obtained.

<Comparative example 2>
50 parts of high molecular weight polyfunctional epoxy resin (“EHPE3150” manufactured by Daicel Co., Ltd.), 50 parts of cyclohexanedimethanol divinyl ether (“CHDVE” manufactured by Nippon Carbide Co., Ltd.) as bifunctional divinyl ether, and a thermal cationic polymerization initiator (King Industries). 0.25 parts of "CXC-1821" manufactured by Daicel Co., Ltd.) was blended and dispersion was attempted with a high-speed rotary mixer, but a high molecular weight polyfunctional epoxy resin ("EHPE3150" manufactured by Daicel Co., Ltd.) was insoluble and a composition was obtained. There wasn't.

<Comparative example 3>
50 parts of bifunctional alicyclic epoxy resin (“Celoxyside 2021P”), 50 parts of cyclohexanedimethanol divinyl ether (“CHDVE”) as bifunctional divinyl ether, and thermal cationic polymerization initiator (CXC-1821) manufactured by King Industries. ”) 0.25 parts were blended and uniformly dispersed with a high-speed rotary mixer to obtain a composition.

<Comparative example 4>
50 parts of bifunctional alicyclic epoxy resin ("Selokiside 2021P"), 50 parts of "EHPE3150" as high molecular weight polyfunctional epoxy resin, and thermal cationic polymerization initiator (King)
0.25 parts of “CXC-1821” manufactured by Industries, Inc.) was blended and uniformly dispersed with a high-speed rotary mixer to obtain a composition.

The compositions prepared in Examples and Comparative Examples were subjected to the following evaluation tests for viscosity, reaction rate, and outgas amount. The results are shown in Table 1 below.

<Viscosity measurement>
The compositions prepared in Examples and Comparative Examples were measured for viscosity at 25 ° C. using a vibrating viscometer (“VM-10A” manufactured by SEKONIC Corporation) and evaluated according to the following criteria.
Excellent (◎): Less than 100 mPas Good (○): 100 mPas or more and less than 300 mPas Possible (△): 300 mPas or more and less than 500 mPas Defective (×): 500 mPas or more or insoluble

<Measurement of reaction rate>
The calorific value before and after the reaction when the compositions prepared in Examples and Comparative Examples were heated at 100 ° C. for 30 minutes and cured was measured with a differential scanning calorimeter (“DSC7000X” manufactured by Hitachi, Ltd.), and the reaction rate was measured. It was calculated from the following formula.
Reaction rate (%) of the composition = 100 × (1-calorific value after curing / calorific value before curing)
The reaction rate was evaluated according to the following criteria.
Good (○): 95% or more Possible (△): 90% or more and less than 95% Poor (×): Less than 90%

<Measurement of outgassing amount>
The compositions prepared in Examples and Comparative Examples were heated at 100 ° C. for 30 minutes to prepare a cured product, and the amount of outgas when heated at 100 ° C. for 2 hours was measured by a differential thermogravimetric simultaneous measuring device (manufactured by Hitachi High-Tech Science Corporation). It was measured by "STA7000").
The amount of outgas was evaluated according to the following criteria.
Excellent (◎): Less than 100ppm Good (○): 100ppm or more and less than 300ppm Possible (△): 300ppm or more and less than 500ppm Defective (×): 500ppm or more

<Measurement of transmittance>
For each of the resin compositions prepared in Examples 1 to 9 and Comparative Examples 1 to 4, the resin composition was placed on a non-alkali glass plate (length 50 mm, width 50 mm, thickness 700 μm, OA-10G manufactured by Nippon Electric Glass Co., Ltd.). After dropping an appropriate amount, the mixture was sandwiched between non-alkali glass of the same size and heated at 100 ° C. for 30 minutes to prepare a sample for transmittance measurement (thickness: 10 μm). As a result of measuring the total light transmittance of the evaluation sample with D65 light using air as a reference using a haze meter manufactured by Suga Test Instruments Co., Ltd., the total light transmittance is 90% or more, showing high transparency. It was confirmed.

In Table 1, the viscosity, reaction rate and outgas amount show the measured values and the evaluation results.
From the results in Table 1, all of the compositions of Examples 1 to 9 have a low viscosity at room temperature and are excellent in coating suitability, and also have a high reaction rate of the curing reaction and are cured after the curing reaction. It was confirmed that the amount of outgas generated is extremely small even when the product is placed at a high temperature, and that a sealing layer that prevents deterioration of the device can be formed for a long period of time.

<Device sealing test>
The sealing property using the organic EL element was evaluated. First, an organic EL element (organic film thickness: 110 nm, cathode thickness: 10 nm) was formed on a glass substrate with indium tin oxide (ITO) (manufactured by Geomatec) 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 using a chemical vapor deposition method (CVD method). Next, the composition produced in Example 1 was dropped onto an organic EL device with a nitride film, and then a non-alkali glass plate was laminated on top of the composition (non-alkali glass plate / composition layer / with a nitride film). Organic EL element / glass substrate with ITO) was prepared. By heating the laminate at 100 ° C. for 30 minutes to cure the composition, a laminate in which the organic EL element was sealed was produced (thickness of the cured product: 10 μm). As a result of applying a voltage to the sealed organic EL element and evaluating the initial characteristics, it was confirmed that good light emission was exhibited and the sealing layer was well formed.

Since the curable resin composition for sealing of the present invention produces a cured product in which the amount of outgas generated is extremely small, it is possible to obtain a sealing layer that prevents deterioration of the device for a long period of time. Further, since the curable resin composition for sealing of the present invention has excellent fluidity at room temperature and can be directly applied to the object to be sealed, a composition layer (coating layer) having uniform properties can be easily formed. It is possible to form a high-performance sealing layer at an intended location.

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

Claims (9)

Encapsulation containing (A) a bifunctional alicyclic epoxy resin having a molecular weight of less than 1000, (B) a polyfunctional epoxy resin having a molecular weight of 1000 or more, (C) a bifunctional vinyl ether compound, and (D) a cationic polymerization initiator. Curable resin composition for use. (B) The curable resin composition for sealing according to claim 1, wherein the polyfunctional epoxy resin has a molecular weight of 10,000 or less. (B) The curable resin composition for sealing according to claim 1 or 2, wherein the polyfunctional epoxy resin has a cyclic skeleton. (C) The curable resin composition for sealing according to any one of claims 1 to 3, wherein the bifunctional vinyl ether compound has a molecular weight of 1000 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. (D) The curable resin composition for sealing according to any one of claims 1 to 5, wherein the cationic polymerization initiator is a thermosetting polymerization initiator. (A) The curable resin composition for sealing according to any one of claims 1 to 6, wherein the bifunctional alicyclic epoxy resin has a molecular weight of 100 or more. The curable resin composition for sealing according to any one of claims 1 to 7, which is used for sealing an organic EL element. An organic EL device in which an organic EL element is sealed with a cured product of the curable resin composition according to any one of claims 1 to 7.