JP6099999B2 - Energy ray curable resin composition - Google Patents

Description

  The present invention relates to an energy ray-curable resin composition containing urethane acrylate (urethane (meth) acrylate). In particular, the present invention relates to a sealing material such as an organic EL element, a semiconductor package, or a liquid crystal panel, or other moisture-proof sealing material or a gasket. Here, usable energy rays include rays such as ultraviolet rays and blue light, and electron rays and other radiation.

  For example, when an organic EL element is used as a display element for each pixel in a flat display device (flat panel display), since the organic EL element is easily deteriorated by humidity, it often becomes a dark spot. Therefore, a sealing material with low moisture permeability is required. In addition, a sealing material for manufacturing a package of an electronic component such as a semiconductor package and a sealing material (sealing material) for sealing a peripheral portion of a liquid crystal panel are also required to have low moisture permeability.

  Conventionally, a thermosetting epoxy resin has been mainly used as such a sealing material. However, in order to complete the curing, for example, there is a problem that it is necessary to carry out curing for a relatively long time by heating to 130 ° C. or higher. Therefore, there has been a problem particularly when an organic EL element made of a material having relatively low heat resistance is sealed.

  Patent Document 1 discloses a polymer having acryloyl groups introduced at both ends of a polymer such as hydrogenated polybutadiene having a weight average molecular weight of 6000 or more as a photocurable sealing material for use in place of a gasket such as a hard disk, The use of a composition comprising an acrylate monomer such as bornyl acrylate is described. According to the results of the examples shown in Table 1, the water vapor transmission rate seems to be almost sufficient for use in various sealants. However, it is assumed that such a resin composition does not have sufficient light transmittance even under conditions where a filler or the like is not added due to fine phase separation or the like. Further, since a relatively high integrated light amount is required, a problem of heat generation is likely to occur, and it seems that it is not very suitable for sealing an organic EL element.

  In Examples of Patent Document 2, isobornyl acrylate is used as a sealing material for electronic paper in order to have flexibility, low moisture permeability, and adhesion to a PET (polyethylene terephthalate) base material. A photocurable resin composition obtained by reacting a urethane compound having an ethylenically unsaturated double bond with a urethane oligomer as a polyisocyanate compound is described. Although the cured resin is considered to be transparent, according to the results of the examples shown in Table 1, the moisture permeability has reached the level required for the sealant that seals the organic EL element itself. It is considered that the lifetime of the manufactured organic EL display cannot be made sufficient.

  Patent Document 3 discloses an epoxy compound such as bisphenol F diglycidyl ether, an oxetane compound, and a photocation as a sealing material for a liquid crystal display and an EL (electroluminescence) display such as an organic EL display. The use of a composition comprising an initiator and an aliphatic thioether is described. However, although the moisture permeability shown in Table 2 is better than the result of Table 1 of Patent Document 2, it does not reach the level required for the sealant that seals the organic EL element itself. Conceivable. Further, since a thioether compound is used, there is a possibility that light transmittance is insufficient.

JP 2006-298964 A JP 2010-144000 JP 2003-096185 A

  This invention is made | formed in view of the above, In energy-beam curable resin composition containing urethane acrylate which can be used for sealing of an optical device etc., it is excellent in transparency of hardened | cured material, an organic EL element, etc. Try to provide something that can improve the moisture resistance of.

As a result of intensive studies to solve the above problems, the present inventor, as a result, polyester polyol (A) which is a condensation polymerization product of 3-methyl-1,5-pentanediol and 1,4-cyclohexanedicarboxylic acid , After reacting the polyisocyanate (B) with the hydroxyl group-containing monoacrylate monomer (C) to obtain urethane acrylate (urethane (meth) acrylate), the monoacrylate monomer (D) having an alicyclic structure or an aromatic ring structure It was found that an energy curable resin composition excellent in moisture resistance and transparency can be obtained by mixing with A, and the present invention has been completed. Note that the description of “(meth)” is intended to make it more clear that a part or all of them are methacrylates.

  According to the present invention, since the cured resin is excellent in transparency and moisture resistance, an energy beam curable resin composition for an optical device sealing agent suitable for sealing an optical device such as an organic EL element is provided. Can be obtained.

It is a typical exploded view of a moisture permeable cup.

1. (A) Polyester polyol having one or more alicyclic structures:
Examples of the alicyclic structure of the polyester polyol (A) include cycloalkane, bicycloalkane, tricycloalkane, hydrogenated naphthalene and norbornane. Of these, cyclohexane is preferable.

  Examples of the polyester polyol (A) having one or more alicyclic structures include condensation polymers of polyhydric alcohols having one or more alicyclic structures and polycarboxylic acids; polyhydric alcohols and one or more alicyclic structures. A polycondensation product with a polyvalent carboxylic acid having a ring structure; a ring-opening polymer of a cyclic ester (lactone) having one or more alicyclic structures; a polyhydric alcohol, a polyvalent carboxylic acid and a cyclic ester having one or more alicyclic structures The reaction product by three types of these components; the reaction product by three types of components, such as a polyhydric alcohol, the polyhydric carboxylic acid which has one or more alicyclic structure, and cyclic ester, etc. can be used. Here, in general, the polyhydric alcohol is a diol, and the polycarboxylic acid is a dicarboxylic acid, but a trihydric or higher polyhydric alcohol or polycarboxylic acid such as triol or tricarboxylic acid is added in a small amount to the diol or dicarboxylic acid. Even if it is added, it can be preferably used. For example, a polyol or polycarboxylic acid having 1.8 to 3.0, particularly 1.9 to 2.4, alcoholic hydroxyl groups or carboxylic acid groups per molecule can be used. In the polyester polyol, substantially all terminals, for example, 95% or more terminals are hydroxyl groups.

  In a polycondensation product of a polyhydric alcohol having one or more alicyclic structures and a polyvalent carboxylic acid, the polyhydric alcohol having one or more alicyclic structures may be used as the polyhydric alcohol having one or more alicyclic structures. Bis (hydroxy) cyclohexane, bis (hydroxymethyl) cyclohexane, bis (hydroxyethyl) cyclohexane, bis (hydroxypropyl) cyclohexane, bis (hydroxymethoxy) cyclohexane, bis (hydroxyethoxy) cyclohexane, bis (hydroxymethoxycyclohexyl) propane, Bis (hydroxyethoxycyclohexyl) propane, bis (hydroxycyclohexyl) methane, bis (hydroxycyclohexyl) propane, bis (hydroxymethyl) cyclopropane, bis (hydroxymethyl) cyclo Tan, bis (hydroxymethyl) cyclopentane, bis (hydroxymethyl) cycloheptane, bis (hydroxymethyl) cyclooctane, bis (hydroxymethyl) cyclononane, bis (hydroxymethyl) cyclodecane, bis (hydroxymethyl) cycloundecane, bis ( Hydroxymethyl) cyclododecane, bis (hydroxymethyl) bicyclobutane, bis (hydroxymethyl) bicyclopentane, bis (hydroxymethyl) bicyclohexane, bis (hydroxymethyl) bicycloheptane, bis (hydroxymethyl) bicyclooctane, bis (hydroxymethyl) ) Bicyclononane, bis (hydroxymethyl) bicyclodecane, bis (hydroxymethyl) bicycloundecane, bis (hydroxymethyl) bicyclododecane, bis ( Droxymethyl) tricycloheptane, bis (hydroxymethyl) tricyclooctane, bis (hydroxymethyl) tricyclononane, bis (hydroxymethyl) tricyclodecane (3 (4), 8 (9) -tricyclo [5.2.1.0 (2 , 6)] decanedimethanol, etc.), bis (hydroxymethyl) tricycloundecane, bis (hydroxymethyl) tricyclododecane, bis (hydroxymethyl) spirooctane, bis (hydroxymethyl) spirononan, bis (hydroxymethyl) spirodecane, Bis (hydroxymethyl) spiroundecane, bis (hydroxymethyl) spirododecane, bis (hydroxymethyl) cyclopentanespirocyclobutane, bis (hydroxymethyl) cyclohexanespirocyclopentane, hydrogenated dimer diol, hydrogenated bisphenol A, etc. It can be illustrated.

  On the other hand, examples of polycarboxylic acids include aliphatic dicarboxylic acids such as malonic acid, maleic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; 1,4-cyclohexane Alicyclic dicarboxylic acids such as dicarboxylic acids; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid and paraphenylenedicarboxylic acid, and aromatic tricarboxylic acids such as trimellitic acid It is done.

  Moreover, the reaction product obtained by making three types of polyhydric alcohol, polyhydric carboxylic acid, and cyclic ester (monomer) which have 1 or more alicyclic structures react can also be mentioned. Examples of the cyclic ester in this case include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone. In the reaction products from the above three kinds of compounds, as the polyhydric alcohol and polycarboxylic acid having one or more alicyclic structures used for the reaction, those exemplified above can be used.

  In the condensation polymerization product of a polyhydric alcohol and a polyhydric carboxylic acid having one or more alicyclic structures, examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4 -Tetramethylenediol, 1,3-tetramethylenediol, 2-methyl-1,3-trimethylenediol, 1,5-pentamethylenediol, neopentyl glycol, 1,6-hexamethylenediol, 3-methyl-1 , 5-pentamethylenediol, 2,4-diethyl-1,5-pentamethylenediol, glycerin, trimethylolpropane, trimethylolethane, cyclohexanediols (such as 1,4-cyclohexanediol), bisphenols (such as bisphenol A) ), Sugar alcohols (such as xylitol and sorbitol) Can be used. Examples of the polyvalent carboxylic acid having one or more alicyclic structures include alicyclic dicarboxylic acids.

  The polyester polyol having a cyclohexane structure can be obtained by a dehydration condensation reaction between a carboxylic acid and an alcohol. For this reason, the following compounds can be used in combination.

  1,2-bis (hydroxymethyl) cyclohexane, 1,3-bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxymethyl) cyclohexane, 1,2-bis (hydroxyethyl) as alcohol components having a cyclohexane structure Cyclohexane, 1,3-bis (hydroxyethyl) cyclohexane, 1,4-bis (hydroxyethyl) cyclohexane, 1,2-bis (hydroxypropyl) cyclohexane, 1,3-bis (hydroxypropyl) cyclohexane, 1,4- Bis (hydroxypropyl) cyclohexane, 1,4-bis (hydroxymethoxy) cyclohexane, 1,4-bis (hydroxyethoxy) cyclohexane, 2,2-bis (4-hydroxymethoxycyclohexyl) propane, 2,2-bis (4 -Hydroxyethoxycyclohexyl) propane, bis (4-hydroxycyclohexyl) Le) methane, 2,2-bis (4-hydroxycyclohexyl) alicyclic glycols such as propane.

  Examples of the carboxylic acid component having a cyclohexane structure include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the like.

  Alcohols such as ethylene glycol, 1,4-butadiene glycol, 2,4-diethylpentanediol, and 3-methyl-pentanediol may be combined with carboxylic acid components having a cyclohexane structure, or alcohol components having a cyclohexane structure. May be combined. Conversely, a carboxylic acid-containing compound such as adipic acid may be combined with an alcohol component having a cyclohexane skeleton. Two or more kinds of carboxylic acid components and alcohol components may be used in combination.

  The weight average molecular weight (Mw) of the polyester polyol (A) having one or more alicyclic structures is preferably in the range of 300 to 10000, more preferably 500 to 5000. More preferably, it is 500-1500. Here, the weight average molecular weight (Mw) can be determined as a polystyrene equivalent value by a GPC apparatus using tetrahydrofuran (THF) as a solvent.

2. (B) Polyisocyanate:
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate , Diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethyl Hexamethylene diisocyanate or diisocyanate compounds obtained by hydrogenating aromatic isocyanates among these diisocyanate compounds (for example, hydrogenated xylylene diisocyanate). Divalent or trivalent diisocyanate compounds such as diphenylmethane diisocyanate, diphenylmethane diisocyanate), triphenylmethane triisocyanate, dimethylenetriphenyl triisocyanate, etc. An isocyanate group-containing compound such as a multimerized polyisocyanate compound is exemplified.

  A trifunctional polyisocyanate compound is preferably used for synthesizing urethane (meth) acrylate having an increased number of functional groups. Specifically, an isocyanurate compound derived from 2,6-hexamethylene diisocyanate and an isocyanurate compound derived from isophorone diisocyanate can be used.

  When using a polyisocyanate compound other than isocyanurate, use a polyisocyanate compound obtained by a reaction between a polyester polyol having three or more hydroxyl groups in one molecule and an excess amount of the following diisocyanate. Is possible. 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p- Phenylene diisocyanate, diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 2,6-hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 2,2, It is possible to use polyisocyanate compounds obtained by reaction with 4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like. Examples of the polyester polyol having three or more hydroxyl groups in one molecule include those obtained from trimellitic acid and an excessive amount of ethylene glycol.

  The molecular weight of the polyisocyanate used to obtain the urethane (meth) acrylate is typically 2000 or less, particularly 1000 or less, even when a multimer or other polyfunctional compound is used.

3. (C) (Meth) acrylate compound having one or more hydroxyl groups:
Hydroxyl-containing (meth) acrylate compounds used to obtain urethane (meth) acrylates include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, ethylene glycol mono (meth) acrylate, propylene glycol mono Examples include (meth) acrylate, 2-hydroxy-3-methoxypropyl acrylate or methacrylate, pentaerythritol triacrylate or methacrylate, N-methylolacrylamide or methacrylamide, N-hydroxyacrylamide or methacrylamide. That is, in the present application, the term “hydroxyl group-containing (meth) acrylate compound” includes a (meth) acrylamide compound. The hydroxyl group-containing (meth) acrylate compound is typically a monomer, contains 1 to 2, preferably 1 hydroxyl group, contains only 1 (meth) acryl group, and has a molecular weight of 1000 or less, particularly 500. It is as follows.

4). Production method of urethane (meth) acrylate:
It can be synthesized by a known method. For example, a polyurethane is obtained by adding a predetermined amount of polyester polyol (A) to an excess amount of polyisocyanate (B) and reacting at 80 ° C. until a predetermined free isocyanate amount is obtained, and further at 70-80 ° C. In the presence of a polymerization inhibitor such as hydroquinone monomethyl ether, the hydroxyl group-containing (meth) acrylate (C) can be charged all at once and heated and stirred at 70 to 80 ° C. until free isocyanate disappears. At this time, in order to promote the reaction, a tin-based catalyst such as dibutyltin dilaurate may be added.

  When manufacturing urethane (meth) acrylate, the equivalent ratio of polyisocyanate (B) to polyester polyol (A) can be set to, for example, 1.5 to 2.5. Moreover, the equivalent ratio of the hydroxyl group-containing (meth) acrylate (C) to the polyisocyanate (B) can be set to, for example, 0.5 to 1.5.

5. (D) Mono (meth) acrylate compound having one or more alicyclic structure or aromatic ring structure:
The (meth) acrylate compound contained together with the urethane (meth) acrylate in the energy ray curable resin composition of the present application is typically a monomer having a molecular weight of 1000 or less, particularly 500 or less, and in particular one Is a compound obtained by dehydration esterification of 1 to 3, especially 1 to 2 monoalcohols having alicyclic or aromatic rings. Preferred examples of such (meth) acrylate compounds containing alicyclic or aromatic rings include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyloxyethyl. (Meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, ethoxylated phenyl (meth) acrylate, isobornyl (meth) acrylate, nonylphenoxyethyl acrylate, phenoxyethyl acrylate, dicyclopentenyloxyethyl acrylate and the like. Among these, isobornyl acrylate, nonylphenoxyethyl acrylate, phenoxyethyl acrylate, and dicyclopentenyloxyethyl acrylate are preferable.

  The ratio of urethane (meth) acrylate in the total weight of urethane (meth) acrylate and (meth) acrylate compound containing an alicyclic ring or aromatic ring is preferably 30 to 90% by weight, more preferably 40 to 80%. % By weight.

6). Polymerization initiators Usable polymerization initiators include both photopolymerization initiators and polymerization initiators using active energy rays such as ultraviolet rays.

  As the photopolymerization initiator, for example, aromatic ketones such as benzophenone, aromatic compounds such as anthracene and α-chloromethylnaphthalene, and sulfur compounds such as diphenyl sulfide and thiocarbamate can be used.

  Examples of polymerization initiators by active energy rays such as ultraviolet rays other than visible light include, for example, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, xanthone , Fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzyl Dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropyl Thioxane , 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -Butanone-1,4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl)- 2,4,4-trimethylpentylphosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and the like can be mentioned.

  As a commercial item of the polymerization initiator by an active energy ray, the product name: Irgacure 184,369,651,500,819,907,784,2959,1000,1300,1700 made from Ciba Specialty Chemicals, for example , 1800, 1850, Darocur 1116, 1173, manufactured by BASF, Inc. Product name: Lucilin TPO, manufactured by UCB, Inc. Product name: Ubekrill P36, manufactured by Fratteri Lamberti, Inc. Product names: Ezacur KIP150, KIP100F, KT37, KT55, KTO46, TZT, KIP75LT, Nippon Kayaku Co., Ltd. brand name: Kayacure DETX, etc. can be mentioned.

  The content of these polymerization initiators varies depending on the type and the like, but as a guideline, the total weight of energy ray-curable components including urethane (meth) acrylate and alicyclic / aromatic ring-containing (meth) acrylate compound (D) is 100. 1 to 8 parts by weight with respect to parts by weight.

  The energy ray source for curing the curable resin composition of the present invention is not particularly limited, and examples thereof include a high pressure mercury lamp, an electron beam, a γ ray, a carbon arc lamp, a xenon lamp, and a metal halide lamp.

  On the other hand, when cured by heating, it can be cured by heating to a temperature range of 60 to 250 ° C.

7). Other components Various additives can be added to the curable resin composition of the present invention, if necessary, in addition to the organic solvent or monomers and various initiators. Examples of additives include light stabilizers, UV absorbers, catalysts, leveling agents, antifoaming agents, polymerization accelerators, antioxidants, flame retardants, infrared absorbers, antistatic agents, slip agents, plasticizers, dispersions Agents and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example in the range which does not exceed the summary.

・「ETEROL 5128」（Mw=2000）
Polychem Systemsにより市販されているシクロヘキサン環含有ポリエステルジオール製品。水酸基価から算出した数平均分子量も約2000。ジエチレングリコールと、エチレングリコールと、シクロヘキサンジカルボン酸との重縮合により得られる。 <Cyclohexane ring-containing polyester polyol>
・ "Kurapol P-1041" (Mw = 1000) and "Kurapol P-2041" (Mw = 2000)
A cyclohexane ring-containing polyester diol product marketed by Kuraray Co., Ltd. The dispersion ratio is close to 1, and the number average molecular weight calculated from the hydroxyl value is about 1000 and about 2000, respectively. It is obtained by polycondensation of 3-methyl-1,5-pentanediol and 1,4-cyclohexanedicarboxylic acid and has the following structure.

・ "ETEROL 5128" (Mw = 2000)
Cyclohexane ring-containing polyester diol products marketed by Polychem Systems. The number average molecular weight calculated from the hydroxyl value is also about 2000. It can be obtained by polycondensation of diethylene glycol, ethylene glycol, and cyclohexanedicarboxylic acid.

・「ニッポラン4009」
日本ポリウレタン工業（株）より市販されているポリブチレンアジペート製品であって、水酸基価から算出した数平均分子量が約1000。
・「R-15HT」
出光石油化学工業（株）より市販されているポリブタジエンジオール製品。重量平均分子量が約1200。 <Analicyclic non-containing polyester polyol for comparative example>
・ "NISSO PBG-1000" (Mw = 1400)
Both-end hydroxy group hydrogenated 1,2-polybutadiene products available from Nippon Soda Co., Ltd. The weight average molecular weight is about 1400 and has the following structure:

・ Nipporan 4009
It is a polybutylene adipate product commercially available from Nippon Polyurethane Industry Co., Ltd., and its number average molecular weight calculated from the hydroxyl value is about 1000.
・ 「R-15HT」
Polybutadiene diol products commercially available from Idemitsu Petrochemical Industries. The weight average molecular weight is about 1200.

<Synthesis of urethane (meth) acrylate>
Into the flask, 44.7 g (0.2 mol) of isophorone diisocyanate was placed, and while stirring under a nitrogen atmosphere, 0.1 mol of a predetermined hexane ring-containing polyester diol described in Table 1 (of "Kurapol P-1041"). 100g) was charged. The temperature was raised to 80 ° C., and the reaction was continued until the free isocyanate content became 50% or less of the diisocyanate charge. Next, after adding hydroquinone monomethyl ether to the polyurethane thus obtained at 70 to 80 ° C., 23.7 g (0.204 mol) of 2-hydroxyethyl acrylate (HEA) was added, and the residual isocyanate concentration was 0. The reaction was carried out until it was less than 1%.

・フェノキシエチルアクリレート：第一工業製薬（株）の「ニューフロンティアPHE」
・ジシクロペンテニルオキシエチルアクリレート：日立化成工業（株）の「FA-512AS」。
・ノニルフェノキシエチルアクリレート：第一工業製薬（株）の「ニューフロンティアNP-1」 <Mono (meth) acrylate monomer for mixing containing alicyclic / aromatic ring>
-Isobornyl acrylate: A product of the same name by Nippon Shokubai Co., Ltd. It has the following structure.

・ Phenoxyethyl acrylate: New Frontier PHE from Daiichi Kogyo Seiyaku Co., Ltd.
・ Dicyclopentenyloxyethyl acrylate: “FA-512AS” from Hitachi Chemical Co., Ltd.
・ Nonylphenoxyethyl acrylate: “New Frontier NP-1” from Daiichi Kogyo Seiyaku Co., Ltd.

<(Meth) acrylate monomer for mixing in Comparative Example>
・ Acryloyl morpholine: A product of the same name from Kojin Film & Chemicals Co., Ltd.
Nonanediol diacrylate: “New Frontier L-C9A” from Daiichi Kogyo Seiyaku Co., Ltd., 1,9-nonanediol diacrylate.
PEG400 diacrylate: “New Frontier PE-400” from Daiichi Kogyo Seiyaku Co., Ltd., polyethylene glycol No. 400 diacrylate.
BisA-4EO diacrylate: “New Frontier BPE4-A” ethylene oxide (4 mol) modified bisphenol A diacrylate from Daiichi Kogyo Seiyaku Co., Ltd.
Hydrogenated BisA-4EO diacrylate: “New Frontier HBPE4” from Daiichi Kogyo Seiyaku Co., Ltd., ethylene oxide (4 mol) modified hydrogenated bisphenol A diacrylate.

<Viscosity of resin liquid>
After cooling the obtained urethane (meth) acrylate, as shown in Table 1, it was mixed with a predetermined alicyclic / aromatic ring-containing (meth) acrylate monomer (D) at a predetermined ratio. Thereafter, the viscosity at 25 ° C. was measured with an E-type viscometer.

<Production of cured film>
The energy curable resin liquid thus obtained was added with a polymerization initiator and mixed uniformly as described below, and then applied onto a fluororesin sheet with a doctor knife and then irradiated with ultraviolet rays.
Energy curable resin liquid (solid content = oligomer + monomer) 100 parts by weight,
Polymerization initiator Irgacure 184 2 parts by weight,
Film thickness: about 0.8mm,
Atmosphere: N ₂ (O ₂ concentration 0.3%),
High pressure mercury lamp 2400mJ / cm ² (2.9W, 5m / min.) X 6 passes

<Moisture permeability test method>
FIG. 1 is a schematic exploded view (clamping screw omitted) of setting the moisture permeable cup. The moisture permeability was measured and calculated in accordance with JIS Z 0208 by the following procedure.
1) Put 15g of CaCl ₂ in a moisture permeable cup.
2) Attach the cured film to the moisture permeable cup.
3) Measure the weight. ... Amg
4) Place in a high-temperature and high-humidity tank with a temperature of 40 ° C and a humidity of 90%.
5) Measure the weight. ... Bmg
6) perform blank test without putting CaCl ₂ simultaneously. ... Change in weight Cmg
7) Calculate with the following formula.
Moisture permeability (g / m ² / 24h) = (Bmg−Amg−Cmg) × 240 / (test time h × test area cm ² )

<Total light transmittance>
Using a haze computer HZ-2 manufactured by Suga Test Instruments Co., Ltd., the total light transmittance when light from the white LED was transmitted through the cured film was determined according to JIS K 7361-1.

In all Examples, a polyester diol having a cyclohexane ring was used, and an alicyclic / aromatic ring-containing (meth) acrylate was used as a monomer mixed with urethane acrylate. As a result, the water vapor transmission rate was 5.5 g / m ² · 24 h or less. In all Examples and Comparative Examples, the total light transmittance was 90 to 92%, which was considered good. Although not shown in the data, the adhesion and durability with the resin material and primary sealant used in the surface layer of the organic EL display element, and the glass plate used for the substrate of the organic EL display panel, Adhesion with a resin plate such as polyethylene terephthalate and its durability were good.

In particular, in Example 2, as a result of using isobonyl acrylate as a monomer mixed with urethane acrylate, the best results were obtained with a water vapor transmission rate of 0 g / m ² · 24 h. Moreover, the viscosity of the resin liquid was also moderately low. On the other hand, in Example 1 in which the ratio of urethane acrylate in the resin liquid was increased, the viscosity was considerably high, and thus a longer time was required for the coating operation to obtain a film.

  On the other hand, even in Example 4 using dicyclopentenyloxyethyl acrylate, the moisture permeability was very low. Moreover, although the viscosity of the resin liquid was a little high compared with Example 2, it was a grade which has almost no influence. On the other hand, in the same raw material composition, in Examples 3 and 5 using an aromatic ring-containing acrylate monomer such as phenoxyethyl acrylate, the moisture permeability was slightly increased. Further, in Example 5 in which nonylphenoxyethyl acrylate was used as a monomer to be mixed, the viscosity of the resin liquid was slightly increased.

On the other hand, in Example 6, the moisture permeability was relatively large as a result of using a hexane ring-containing polyester diol having a molecular weight of 2 times in the same raw material composition as in Example 1. Also, the viscosity was slightly increased. In Reference Example 1 , as a result of using a slightly different type of hexane ring-containing polyester diol in the same composition as in Example 6, the moisture permeability was higher than that in Example 6.

In Comparative Examples 1 to 5, the same polyester diol and urethane acrylate as in Examples 1 to 5 were used, and the acrylate compound mixed with urethane acrylate was variously changed. As a result, the water vapor transmission rate became 9.4 g / m ² · 24 h or more. In particular, in Comparative Example 1, when a monoacrylate compound having a morpholine ring was used, the moisture permeability became extremely large. In Comparative Examples 4 to 5, an acrylate monomer having two aromatic rings and two alicyclic rings was used, but because it was diacrylate, the viscosity of the resin liquid increased and the moisture permeability was also large. . In Comparative Example 2, when nonane diacrylate was used, the viscosity of the resin liquid was the same as in Examples 2 to 3 and the like, but the moisture permeability was also increased.

In Comparative Examples 6 to 7 using a polyester diol having no alicyclic ring in the structure, the moisture permeability was 7.5 g / m ² · 24 h or more. Further, in Comparative Example 8 using a kind of polybutadiene diol product instead of polyester diol, urethane acrylate and phenoxyethyl acrylate monomer are not mixed and separated, and a definite cured film cannot be obtained. It was.

  A resin composition for an encapsulant that is excellent in transparency and moisture resistance can be obtained. In particular, it is useful as a sealant for optical devices such as organic EL elements that require a high degree of moisture resistance.

Claims (3)

(A) a polyester polyol which is a condensation polymerization product of 3-methyl-1,5-pentanediol and 1,4-cyclohexanedicarboxylic acid ;
(B) a polyisocyanate;
(C) a urethane (meth) acrylate obtained by reacting with a (meth) acrylate compound having one or more hydroxyl groups, and (D) a mono (meth) acrylate compound having one or more alicyclic or aromatic ring structures. An energy ray-curable resin composition comprising: 2. The energy according to claim 1, wherein (D) is one or more selected from isobornyl acrylate, nonylphenoxyethyl acrylate, phenoxyethyl acrylate, and dicyclopentenyloxyethyl acrylate. A linear curable resin composition. Claim 1 or 2 sealant composition for optical device characterized by containing the radiation-curable resin composition according to.

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