KR102465211B1 - A sealing material for display elements and a cured product thereof, a frame sealing material for an organic EL element, and a surface sealing material for an organic EL element - Google Patents

Abstract

It makes it a subject to not only fully be able to seal a display element, but to provide the sealing material for display elements in which stripe unevenness does not generate|occur|produce easily after sealing. The sealing material for display elements which solves the said subject, (A) an aliphatic (meth)acryl monomer, (B) an azo-type polymerization initiator, and (C) 2,2,6,6-tetramethylpiperidine 1-oxyl a free radical derivative and (D) a silane coupling agent having a (meth)acryl group and having a weight average molecular weight of 400 to 500,000. Moreover, the glass transition temperature of the hardened|cured material obtained by heating at 100 degreeC for 30 minute(s) is 46 degreeC or more.

Description

A sealing material for display elements and a cured product thereof, a frame sealing material for an organic EL element, and a surface sealing material for an organic EL element

The present invention relates to a sealing material for display elements and a cured product thereof, a frame sealing material for an organic EL element, and a surface sealing material for an organic EL element.

BACKGROUND ART Organic EL (Electro-Luminescence) elements are used in displays, lighting devices, and the like because of their low power consumption. Since the organic EL element is easily deteriorated by moisture and oxygen in the air, it is generally sealed and used by various sealing members.

The organic EL device can be, for example, a structure including a substrate, an organic EL element disposed on the substrate, and a sealing substrate paired with the substrate. As a method of sealing the organic EL element of such a structure, a sealing material is applied in a frame shape to the outer periphery of a substrate on which the organic EL element is disposed (hereinafter also referred to as "display element side substrate"), and the display element side substrate is used by the sealing material. and a method of bonding a sealing substrate (frame sealing method) is mentioned. Moreover, the method (surface sealing method) of apply|coating a sealing material between a sealing substrate and a display element side board|substrate, and between an organic electroluminescent element and a sealing substrate, and bonding the display element side board|substrate and a sealing substrate with the said sealing material is also mentioned.

As a sealing material for sealing various display elements, such as an organic electroluminescent element, the thermosetting composition containing an aliphatic (meth)acryl monomer, an azo polymerization initiator, and a tetramethylpiperidine free radical derivative is proposed (patent document 1). ).

Japanese Patent Laid-Open No. 2007-186521

In recent years, in order to increase the display area of a display device, it is calculated|required to further narrow the width|variety of the frame of the housing arrange|positioned around the display surface. For this reason, the area|region which was conventionally covered with the frame of a housing is also exposed as a display surface. And when the display element is surface-sealed with the conventional sealing material, as shown in FIG. 1, the outer periphery side of the display area (FIG. 1 shows the dam material 11 and the sealing material hardened|cured material 12 in its vicinity). In some cases, a pattern-like stripe (hereinafter also referred to as "striped unevenness") may occur. Moreover, even when the conventional sealing material was used as a frame sealing material, the same streaked nonuniformity may generate|occur|produce. When such streaked non-uniformity is exposed on the display surface, there has been a problem of impairing the appearance of the display device.

The present invention has been made in view of the above circumstances. That is, an object of this invention is not only to be able to fully seal a display element, but to provide the sealing material for display elements which stripe nonuniformity is hard to generate|occur|produce after sealing.

That is, the 1st of this invention relates to the following sealing materials for display elements.

[1] (A) an aliphatic (meth)acryl monomer, (B) an azo polymerization initiator, and (C) 2,2,6,6-tetramethylpiperidine 1- represented by the following general formula (1) A display device comprising an oxyl free radical derivative and (D) a (meth)acryl group and a silane coupling agent having a weight average molecular weight of 400 to 500,000, and a cured product obtained by heating at 100° C. for 30 minutes has a glass transition temperature of 46° C. or higher. sealant for use.

(In the general formula (1), R is H, a hydroxyl group, an oxo group, an amino group, a cyano group, an acetamide group, a methoxy group, a carboxy group, a palmitamide group, a methacryloyl group, an isothiocyanate group, 2-chloro selected from the group consisting of an acetamide group, a 2-iodoacetamide group, a (9-acridinecarbonyl)amino group, and a [2-[2-(4-iodophenoxy)ethoxy]carbonyl]benzoyl group represents any one group that becomes

[2] The sealing material for display elements according to [1], wherein the (D) silane coupling agent contains two or more (meth)acryl groups in a molecule.

[3] The sealing material for display elements according to [1] or [2], wherein the (D) silane coupling agent contains two or more Si atoms in a molecule.

[4] The sealing material for display elements according to any one of [1] to [3], wherein the (D) silane coupling agent contains a siloxane bond in the main chain.

[5] The sealing material for display elements according to any one of [1] to [4], wherein the coefficient of linear expansion in 35°C to 100°C of the cured product obtained by heating at 100°C for 30 minutes is 50 or more and 250 or less.

[6] The sealing material for display elements according to any one of [1] to [5], wherein the (A) aliphatic (meth)acryl monomer contains 5 to 50% by mass of a trifunctional or higher (meth)acryl monomer.

[7] The sealing material for display elements according to any one of [1] to [6], wherein the (A) aliphatic (meth)acryl monomer has a weight average molecular weight of 400 or more and 2000 or less.

[8] The sealing material for display elements according to any one of [1] to [7], wherein the (A) aliphatic (meth)acryl monomer is a methacryl monomer.

[9] (A-2) The sealing material for display elements according to any one of [1] to [8], further comprising a ring structure-containing (meth)acryl monomer.

[10] The sealing material for display elements according to [9], wherein the (A-2) ring structure-containing (meth)acryl monomer contains a bisphenol A-type structure.

[11] The sealing material for display elements according to any one of [1] to [10], further comprising a leveling agent.

The 2nd of this invention relates to the following hardened|cured material of the frame sealing material for organic electroluminescent elements, the surface sealing material for organic electroluminescent elements, and the sealing material for display elements.

[12] A frame sealing material for an organic EL device, comprising the sealing material for a display device according to any one of [1] to [11], which is used for frame sealing of an organic EL device.

[13] A surface sealing material for an organic EL element, comprising the sealing material for a display element according to any one of [1] to [11], and used for surface sealing of an organic EL element.

[14] The cured product of the sealing material for a display element according to any one of [1] to [11].

ADVANTAGE OF THE INVENTION According to this invention, not only can a display element be fully sealed, but it can be set as the sealing material for display elements which stripe nonuniformity is hard to generate|occur|produce after sealing.

BRIEF DESCRIPTION OF THE DRAWINGS It is a photograph which shows the hardened|cured material of the sealing material for display elements in the vicinity of a dam material at the time of surface-sealing a display element with the conventional sealing material for display elements.
Fig. 2A is a photograph showing a cured product of the sealing material for display elements near the spacer of the stripe unevenness evaluation sample of Example 1, and Fig. 2B is a photograph showing the sealing material for display elements near the spacer of the stripe unevenness evaluation sample of Comparative Example 1. It is a picture representing the cargo.

The sealing material for display elements of this invention is used as a surface sealing material for surface sealing various display elements, or a frame sealing material for frame sealing. When surface sealing a display element, a dam material is arrange|positioned along the outer periphery of a sealing substrate or a display element side board|substrate normally. And the sealing material is apply|coated in the area|region surrounded by the said dam material. Then, in the state which made the sealing substrate and the display element side board|substrate oppose, the sealing material is hardened, and the sealing substrate and the display element side board|substrate (Hereinafter, these are collectively referred to as a "substrate") are joined. However, when the conventional sealing material is used for bonding, the subject that it is easy to generate|occur|produce streaks nonuniformity on the outer peripheral side of a display apparatus tends to generate|occur|produce. The reason is considered as follows.

The bonding of the substrate is generally performed in a vacuum (for example, in an environment of 1 Pa or less). At this time, the low molecular weight component in the sealing material volatilizes easily, and the silane coupling agent mainly volatilizes in the conventional sealing material. And when a silane coupling agent volatilizes, the adhesive strength of a board|substrate and a sealing material (or its hardened|cured material) will not become high enough. On the other hand, the face sealant shrinks along with curing. Therefore, when a surface sealing material is hardened, it will be easy to generate|occur|produce a gap|interval between a board|substrate and a surface sealing material, and the said gap|interval will be observed as a streaked nonuniformity. In addition, on the outer peripheral side of the board|substrate, the dam material is arrange|positioned as mentioned above. Therefore, when the face sealant cures and shrinks, it is difficult for the substrate to follow the face sealant in the region concerned. Accordingly, it is considered that the streaked unevenness is concentrated on the outer peripheral side of the substrate. Here, it is thought that the same subject arises also when frame-sealing using the sealing material for display elements.

On the other hand, the sealing material for display elements of this invention contains the silane coupling agent which has (D) (meth)acryl group and is a weight average molecular weight of 400-500,000. Since the said silane coupling agent has a comparatively large molecular weight, it is hard to volatilize also in vacuum. Moreover, since it has a (meth)acryl group, affinity with the other component (particularly (A) aliphatic (meth)acryl monomer) in the sealing material for display elements is high. Therefore, when the sealing material for display elements is apply|coated, it is hard to float on the surface, and it is hard to volatilize.

Moreover, when the said (D) silane coupling agent hardens the sealing material for display elements, a (meth)acryl group chemically bonds with the (A) aliphatic (meth)acryl monomer etc. On the other hand, (D) Si atoms in the silane coupling agent bond to a glass substrate or the like with siloxane. Therefore, by the said (D) silane coupling agent, the adhesiveness of a sealing material and a glass substrate becomes very high, and it becomes difficult to generate|occur|produce a gap between these. Further, (D) the silane coupling agent has a large molecular weight and a relatively bulky skeleton. Therefore, the effect that the shrinkage|contraction at the time of hardening of the sealing material for display elements is suppressed is also acquired.

Moreover, as for the sealing material for display elements of this invention, the glass transition temperature (Tg) of hardened|cured material is 46 degreeC or more. Therefore, the hardened|cured material of the sealing material for display elements is hard to deform|transform or shrink|contract after hardening, and it becomes difficult to generate|occur|produce the above-mentioned stripe unevenness also by this point. The glass transition temperature of the cured product of the sealing material for display element is determined by performing thermal analysis with a thermomechanical analyzer (TMA apparatus) or the like at a temperature increase rate of 5° C./min. is the value to be

Moreover, since the sealing material for display elements of this invention mainly contains the (A) aliphatic (meth)acryl monomer, the viscosity is low suitably, and it can apply|coat stably. In addition, since the polymerization initiator is (B) an azo polymerization initiator, the (A) aliphatic (meth)acryl monomer can be cured in a short time, and the gas affecting the display element during or after curing of the sealing material for display element is released. difficult to occur In addition, although (A) the thermosetting type sealing material for display elements containing an aliphatic (meth)acrylic monomer generally has low stability in many cases, the sealing material for display elements of this invention is (C) tetramethylpiperidine free radical derivatives. Therefore, it is difficult to react (A) an aliphatic (meth)acryl monomer and (B) azo polymerization initiator during storage or inside an application|coating apparatus etc., and it is excellent also in stability. Hereinafter, each component which the sealing material for display elements contains is demonstrated.

(A) aliphatic (meth)acrylic monomer

(A) The aliphatic (meth)acryl monomer is not particularly limited as long as it is a monomer having a (meth)acryl group and an aliphatic chain in the molecule and polymerized by heating. (A) The (meth)acryl monomer which has either linear or branched structure may be sufficient as an aliphatic (meth)acryl monomer. Here, (meth)acryl in this specification shows an acryl and/or methacryl. The sealing material for display elements may contain only 1 type (A) aliphatic (meth)acryl monomer, and may contain it 2 or more types.

(A) It is preferable that they are 400 or more and 2000 or less, and, as for the weight average molecular weight of an aliphatic (meth)acryl monomer, it is more preferable that they are 500 or more and 1000 or less. Incidentally, in this specification, the "weight average molecular weight" may be a molecular weight derived from the structure of the monomer, or may be a value (in terms of polystyrene) measured by GPC (gel permeation chromatography). (A) When the weight average molecular weight of an aliphatic (meth)acryl monomer is 2000 or less, the viscosity of the sealing material for display elements does not become high too much, but the applicability|paintability of the sealing material for display elements becomes favorable easily. On the other hand, when the sealing material for display elements is apply|coated as the weight average molecular weight of (A) aliphatic (meth)acryl monomer is 400 or more, (A) aliphatic (meth)acryl monomer will become difficult to volatilize. Incidentally, when the (A) aliphatic (meth)acryl monomer is required to be more difficult to volatilize, the amount of the monomer having a weight average molecular weight of less than 400 with respect to the total amount of (A) the aliphatic (meth)acryl monomer is less than 10% by mass It is preferable to set it as 5 mass %, and it is more preferable to set it as 5 mass %.

In addition, (A) Although the monomer which has any group of an acryl group and a methacryl group may be sufficient as an aliphatic (meth)acryl monomer, It is a monomer which has a methacryl group, ie, the direction of a methacryl monomer is preferable. The reaction rate of a methacryl monomer is slower than an acryl monomer, and it is hard to generate|occur|produce a stop reaction. Therefore, when the sealing material for display elements contains a methacrylic monomer, when hardening the sealing material for display elements, molecular weight will become large easily, and the intensity|strength of hardened|cured material will become high easily.

(A) Although one may be sufficient as the number of the (meth)acryl group which an aliphatic (meth)acryl monomer contains, it is preferable from a viewpoint that the hardened|cured material intensity|strength of the sealing material for display elements becomes high easily that it is two or more.

In addition, the aliphatic chain which (A) the aliphatic (meth)acryl monomer contains may be linear or branched may be sufficient as it. In addition, a structure in which a plurality of alkylene oxides such as polyethylene oxide and polypropylene oxide are linked may be sufficient. (A) When an aliphatic (meth)acryl monomer has an aliphatic chain, the viscosity of the sealing material for display elements becomes low easily, and also the softness|flexibility of the hardened|cured material obtained becomes high easily.

(A) Specific examples of the aliphatic (meth)acryl monomer include di(meth)acryl, such as polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polytetramethylene glycol di(meth)acrylate. rate; Ethylene oxide modified trimethylolpropane tri(meth)acrylate, glycerin polyethylene glycol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerin polyglycidyl polyfunctional (meth)acrylates, such as ether poly(meth)acrylate, etc. are contained.

Here, it is preferable that the (A) aliphatic (meth)acryl monomer contains a bifunctional (meth)acryl monomer from a viewpoint that a viscosity becomes low easily suitably. Specifically, the amount of the bifunctional (meth)acryl monomer is preferably 50 mass% or more and 100 mass% or less, more preferably 50 to 95 mass%, based on the total amount of the (A) aliphatic (meth)acryl monomer. , more preferably 60 to 90 mass%. If the quantity of a bifunctional (meth)acryl monomer is the said range, the viscosity of the sealing material for display elements will become low suitably, and application|coating stability will become high. Among the above-mentioned, as for the bifunctional (A) aliphatic (meth)acryl monomer, polyethyleneglycol di(meth)acrylate or polypropylene glycol di(meth)acrylate is especially preferable.

On the other hand, from the viewpoint of less volatilization at the time of application of the sealing material for display elements and easy to increase the adhesive strength to the substrate, (A) the aliphatic (meth)acryl monomer contains a trifunctional or more (meth)acryl monomer. desirable. When a trifunctional or more (meth)acryl monomer is included, the amount thereof is preferably 5% by mass or more and 50% by mass or less, more preferably 10 to 40% by mass, based on the total amount of (A) aliphatic (meth)acryl monomer. do. Moreover, it is especially preferable that the quantity of the trifunctional (meth)acryl monomer is the said range. As a trifunctional (meth)acryl monomer, ethylene oxide modified|denatured trimethylol propane tri(meth)acrylate is preferable.

(A-2) Ring structure-containing (meth)acrylic monomer

It is preferable that the sealing material for display elements contains the (A-2) ring structure containing (meth)acryl monomer further. (A-2) The ring structure contained in the ring structure-containing (meth)acryl monomer may be any of an aromatic ring, an aliphatic ring (alicyclic), or a heterocyclic ring. When the sealing material for display elements contains the above-mentioned (A) aliphatic (meth)acryl monomer and (A-2) ring structure containing (meth)acryl monomer, the intensity|strength of the hardened|cured material of the sealing material for display elements will become high easily. The sealing material for display elements may contain 1 type (A-2) ring structure containing (meth)acryl monomer, and may contain it 2 or more types.

Here, it is preferable that they are 400 or more and 2000 or less, and, as for the weight average molecular weight of (A-2) ring structure containing (meth)acryl monomer, it is more preferable that they are 500 or more and 1000 or less. When a weight average molecular weight is 2000 or less, the viscosity of the sealing material for display elements does not become high too much, but the applicability|paintability of the sealing material for display elements becomes favorable easily. On the other hand, when the sealing material for display elements is apply|coated as a weight average molecular weight is 400 or more, (A-2) ring structure containing (meth)acryl monomer will become difficult to volatilize. When it is required to be more difficult to volatilize, the amount of (A-2) ring structure-containing (meth)acrylic monomer having a weight average molecular weight of less than 400 is (A) an aliphatic (meth)acrylic monomer and (A-2) ring structure-containing ( It is preferable to set it as less than 10 mass % with respect to the total amount of a meth)acryl monomer, and it is more preferable to set it as less than 5 mass %.

Examples of the (A-2) ring structure-containing (meth)acrylic monomer having an aromatic ring include (poly)ethoxy-modified bisphenol A di(meth)acrylate, (poly)propoxy-modified bisphenol A di(meth)acrylate , (poly) ethoxy (poly) propoxy modified bisphenol A di (meth) acrylate having a bisphenol A-type structure such as di (meth) acrylate; (poly)ethoxy-modified bisphenol F di(meth)acrylate, (poly)propoxy-modified bisphenol F di(meth)acrylate, (poly)ethoxy(poly)propoxy-modified bisphenol F di(meth)acrylate, etc. Di (meth) acrylate having a bisphenol F-type structure of; (poly)ethoxy-modified bisphenol S di(meth)acrylate, (poly)propoxy-modified bisphenol S di(meth)acrylate, (poly)ethoxy(poly)propoxy-modified bisphenol S di(meth)acrylate, etc. Di (meth) acrylate having a bisphenol S-type structure of; di(meth)acrylates having a biphenol structure such as biphenol (poly) ethoxy di (meth) acrylate and biphenol (poly) propoxy di (meth) acrylate; phthalic acid-modified pentaerythritol tri(meth)acrylate; Dihydroxynaphthalene (poly) ethoxydi (meth) acrylate, dihydroxynaphthalene (poly) propoxy di (meth) acrylate, binaphthol di (meth) acrylate, binaphthol (poly) ethoxy di (meth) (meth)acrylates having condensed rings such as acrylate, binaphthol (poly) propoxydi (meth) acrylate, and (poly) caprolactone-modified binaphthol di (meth) acrylate; Bisphenol fluorenedi(meth)acrylate, bisphenoxymethanol fluorenedi(meth)acrylate, bisphenoxyethanolfluorenedi(meth)acrylate, bisphenoxy(poly)caprolactonefluorenedi di(meth)acrylate which has several aromatic rings, such as (meth)acrylate; a reaction product of a biphenyl type phenol aralkyl epoxy resin and acrylic acid; etc. are included.

Examples of the (A-2) ring structure-containing (meth)acrylic monomer having an aliphatic ring include hydrogenated bisphenol A (poly)ethoxydi(meth)acrylate, hydrogenated bisphenol A (poly)propoxydi(meth)acryl Rate, hydrogenated bisphenol F (poly) ethoxydi (meth) acrylate, hydrogenated bisphenol F (poly) propoxy di (meth) acrylate, hydrogenated bisphenol S (poly) ethoxy di (meth) acrylate, hydrogenated bisphenol S (poly) propoxydi (meth) acrylate and the like.

In the example of the (A-2) ring structure containing (meth)acryl monomer which has a heterocyclic ring, isocyanuric acid ethylene oxide modified|denatured di(meth)acrylate, ε-caprolactone modified tris((meth)acroxyethyl)iso and cyanurate, isocyanuric acid ethylene oxide-modified di and triacrylate, hydroxypivalaldehyde-modified trimethylolpropane di(meth)acrylate, spiroglycol di(meth)acrylate, and the like.

Among the above, from the viewpoint of easy availability, etc., (A-2) ring structure-containing (meth)acryl monomer having an aromatic ring is preferable, (poly)ethoxy-modified bisphenol A di(meth)acrylate, ( Monomers having a bisphenol A-type structure such as poly)propoxy-modified bisphenol A di(meth)acrylate and (poly)ethoxy(poly)propoxy-modified bisphenol A di(meth)acrylate are particularly preferred.

(A) The ratio (mass ratio) of the aliphatic (meth)acryl monomer to the (A-2) ring structure-containing (meth)acryl monomer is preferably 20:80 to 90:10, and 30:70 to 70:30 more preferably.

Here, the total amount of the (A) aliphatic (meth)acryl monomer and (A-2) ring structure-containing (meth)acryl monomer is preferably 90 parts by mass or more and 99.9 parts by mass or less with respect to 100 parts by mass of the sealing material for display element, It is more preferable that they are 95 mass parts or more and 99.9 mass parts or less. (A) When content of the aliphatic (meth)acryl monomer and (A-2) ring structure containing (meth)acryl monomer is the said range, various display elements are oxygen, moisture, etc. in air|atmosphere by the hardened|cured material of the sealing material for display elements. sufficiently protected from

(B) azo polymerization initiator

(B) The azo-based polymerization initiator is a compound having an azo group that is decomposed by heat to generate free radicals, and is a compound for curing (polymerizing) the above-described (A) aliphatic (meth)acryl monomer or the like. In general, the polymerization initiator volatilizes from the cured product of the sealing material for display elements, or decomposition products of the polymerization initiator (for example, low molecular weight substances such as acetone and toluene, polar substances having hydroxyl groups or amino groups), etc. volatilize, so that the display element is likely to be affected by On the other hand, in the (B) azo polymerization initiator, the radical component generated by heat is not decomposed and contributes to the polymerization, so that the low molecular weight component is less likely to be generated. Therefore, it is hard to generate|occur|produce the outgas which affects a display element from the coating film of the sealing material for display elements, or hardened|cured material. The sealing material for display elements may contain 1 type (B) azo type polymerization initiator, and may contain it 2 or more types.

(B) The azo polymerization initiator may be any compound of an azonitrile compound, an azoester compound, an azoamide compound, an azoamidine compound, an azoimidazoline compound, or a high molecular weight azo compound.

Examples of the azonitrile compound include 2,2'-azobis(isobutyronitrile), 2,2'-azobis-2-methylisobutyronitrile, 1,1'-azobis(cyclohexane-1- carbonitrile), 1-[(1-cyano-1-methylethyl)azo]formamide, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2' -azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 4,4'-azobis(4-cyanovaleric acid), etc. are included.

Examples of the azoester compound include dimethyl 2,2'-azobis(2-methylpropionate), dimethyl 1,1'-azobis(1-cyclohexanecarboxylate), 1,1'-azobis- (1-acetoxy-1-phenylethane) and the like.

Examples of the azoamide compound include 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis(N-cyclohexyl-2-methylpropionamide), 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxy ethyl]propionamide, 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)]propionamide, and the like.

Examples of the azoamidine compound include 2,2'-azobis(2-methylpropionamidine)dihydrochloride, 2,2'-azobis(N-(2-carboxyethyl)-2-methylpropionamidine ) tetrahydrate, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis(1-imino-1-pyrrolidino-2-methylpropane)dihydrochloride etc. are included.

Examples of the azoimidazoline compound include 2,2'-azobis[2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane]dihydroxychloride, 2,2 '-Azobis[2-(2-imidazolin-2-yl)propane], 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2 -azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate and the like.

Examples of the high molecular weight azo compound include trade name VPE-0201, trade name VPE-0401, trade name VPE-0601, trade name VPS-1001 (all manufactured by Wako Pure Chemical Industries, Ltd.).

Among the above, an azonitrile compound or an azoester compound is preferable.

(B) The azo polymerization initiator preferably has a high decomposition temperature, specifically, preferably has a 10-hour half-life temperature (decomposition temperature) of 45°C to 85°C, more preferably 55°C to 70°C . (B) When the decomposition temperature of the azo polymerization initiator is high, even when the sealing material for display elements is maintained in an oxygen-free environment and 40° C. or lower for a certain period of time, the sealing material for display elements is difficult to deteriorate, so that the application of the sealing material for display elements is stable. can be done with

(B) The azo polymerization initiator is 0.05 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the total amount of the (A) aliphatic (meth)acryl monomer and (A-2) ring structure-containing (meth)acryl monomer. It is preferable, and it is more preferable that 0.1 mass part or more and 3 mass parts or less are contained. (B) When the azo polymerization initiator is contained within the above range, it becomes possible to sufficiently thermoset the (A) aliphatic (meth)acryl monomer and the (A-2) ring structure-containing (meth)acryl monomer.

(C) tetramethylpiperidine free radical derivatives

(C) A tetramethylpiperidine free radical derivative functions as a polymerization inhibitor in the sealing material for display elements. Therefore, when the sealing material for display elements contains the said compound, the pot life of the sealing material for display elements will become long. The sealing material for display elements may contain 1 type (C) tetramethylpiperidine free radical derivative, and may contain 2 or more types.

Here, the (C) tetramethylpiperidine free radical derivative contained in the sealing material for display elements of this invention is a compound represented by following General formula (1).

In the general formula (1), R represents a monovalent or divalent group, specifically, H, a hydroxyl group, an oxo group, an amino group, a cyano group, an acetamide group, a methoxy group, a carboxy group, a palmitamide group, A methacryloyl group, an isothiocyanate group, a 2-chloroacetamide group, a 2-iodoacetamide group, a (9-acridinecarbonyl)amino group, and [2-[2-(4-iodophenoxy) It represents any one group selected from the group consisting of shi) ethoxy] carbonyl] benzoyl group.

Moreover, among the above-mentioned, the compound whose R in General formula (1) is H, an oxo group, or a hydroxyl group is preferable from a viewpoint, such as availability.

(C) The tetramethylpiperidine free radical derivative is 0.0005 parts by mass or more and 0.2 parts by mass based on 100 parts by mass of the total amount of the (A) aliphatic (meth)acryl monomer and (A-2) ring structure-containing (meth)acryl monomer It is preferable that it is contained below, and it is more preferable that 0.001 mass part or more and 0.1 mass part or less are contained. (C) When the tetramethylpiperidine free radical derivative is included in the above range, the pot life of the sealing material for display elements can be lengthened. Further, when the amount of the (C) tetramethylpiperidine free radical derivative becomes excessive, the thermosetting property of the sealing material for display element may decrease, but (A) an aliphatic (meth)acryl monomer and (A-2) ring structure Thermosetting property of the sealing material for display elements can be made favorable in it being 0.2 mass part or less with respect to 100 mass parts of total amounts of a containing (meth)acryl monomer.

(D) Silane coupling agent

(D) A silane coupling agent will not restrict|limit, if it is a silane coupling agent which has a (meth)acryl group and is a weight average molecular weight of 400-500,000 in particular. As above-mentioned, when the sealing material for display elements contains (D) a silane coupling agent, the adhesive strength of the hardened|cured material of the sealing material for display elements, and a board|substrate will become high.

(D) Although a silane coupling agent should just have a (meth)acryl group, it is preferable to have two or more (meth)acryl groups in a molecule|numerator. Moreover, it is preferable that the equivalent of a (meth)acryl group is 100-15,000 g/mol, and it is more preferable that the equivalent of a (meth)acryl group is 120-1,000 g/mol. (D) When a silane coupling agent contains a some (meth)acryl group, the affinity with respect to the (A) aliphatic (meth)acryl monomer of the (D) silane coupling agent will increase. As a result, when the sealing material for display elements is apply|coated, (D) a silane coupling agent becomes difficult to volatilize. Moreover, when the number of (meth)acryl groups is the said range, at the time of hardening of the sealing material for display elements, (D) The (meth)acryl group in a silane coupling agent chemically bonds enough with the (A) aliphatic (meth)acryl monomer. (D) The number of (meth)acryl groups in the silane coupling agent and the equivalent of (meth)acryl groups can be specified by NMR, IR method, or the like.

On the other hand, (D) Although the silane coupling agent may contain only one Si atom in a molecule|numerator, it is preferable to contain two or more Si atoms in a molecule|numerator. (D) When a silane coupling agent contains several Si atoms in a molecule|numerator, it will be easy to siloxane bond between the hardened|cured material of the sealing material for display elements, and a board|substrate, and these adhesive strength will become high easily. As a result, it becomes difficult to generate|occur|produce a gap|interval between the hardened|cured material of the sealing material for display elements, and a board|substrate, and it becomes difficult to generate|occur|produce the above-mentioned stripe nonuniformity.

In addition, (D) The silane coupling agent may be a compound containing a siloxane bond (-Si-O-Si-) in a main chain, and the compound containing an organic chain in a main chain may be sufficient as it. Moreover, linear form may be sufficient as a principal chain, and branched chain form may be sufficient as it, and may have a network structure etc.

(D) The molecular weight of a silane coupling agent should just be 400-500,000. (D) When the molecular weight of a silane coupling agent is 400 or more, (D) silane coupling agent becomes difficult to volatilize from the sealing material for display elements also in a vacuum. Moreover, the structure becomes bulky easily, and it becomes easy to suppress the cure shrinkage of the sealing material for display elements. On the other hand, when molecular weight is 500,000 or less, the viscosity of the sealing material for display elements does not become high too much, Furthermore, it becomes easy to mix with the component in the sealing material for display elements. (D) The said molecular weight of a silane coupling agent is a weight average molecular weight, and is a value specified by GPC.

The (D) silane coupling agent may be, for example, a commercially available one, and examples of the commercially available product include: trade name X-12-1048, trade name X-12-1050, trade name X-40-9296, KR-513 (all are new S-Silicone Co., Ltd.) is included.

Here, (D) the silane coupling agent is contained in 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the total amount of the (A) aliphatic (meth)acrylic monomer and (A-2) ring structure-containing (meth)acryl monomer It is preferable, and it is more preferable that 0.5 mass part or more and 5 mass parts or less are contained. (D) When a silane coupling agent is contained in the said range, the adhesive strength of the hardened|cured material of the sealing material for display elements, and a board|substrate can be raised.

(E) leveling agent

The sealing material for display elements may contain the (E) leveling agent further. (E) A leveling agent is a compound which orientates to the coating-film surface of the sealing material for display elements, uniformizes the surface tension, makes it hard to generate|occur|produce a repelling etc., and makes it easy to spread on a to-be-coated object.

(E) When a leveling agent adjusts the surface tension of the coating-film surface of the sealing material for display elements, the wettability of the composition with respect to a to-be-coated object will improve and it will become easy to improve the fluidity|liquidity and defoaming property of a coating-film surface. Incidentally, these effects are often expressed with a small amount of addition. Therefore, as the (E) leveling agent, it is preferable to use a silicone-based polymer or an acrylate-based polymer having a relatively small surface-modifying action. A well-known thing can be used for such a silicone type polymer and an acrylate type polymer.

(E) It is preferable that 0.01-1 mass part of a leveling agent is contained with respect to 100 mass parts of total amounts of (A) aliphatic (meth)acryl monomer and (A-2) ring structure containing (meth)acryl monomer, 0.05- It is more preferable that it is 0.5 mass part. (E) When content of a leveling agent is fixed or more, the leveling agent of sufficient quantity will orientate to the coating-film surface of the sealing material for display elements easily, and sufficient leveling effect will be easy to be acquired. On the other hand, when content of (E) leveling agent is below fixed, (E) leveling agent, compatibility of (A) aliphatic (meth)acryl monomer, and (A-2) ring structure containing (meth)acryl monomer, and transparency of hardened|cured material It is difficult to damage.

(F) other ingredients

The sealing material for display elements is the range which does not impair the effect of this invention largely. WHEREIN: Other resin may be included. The other resin can be, for example, a thermosetting resin or the like. An epoxy resin, a phenol resin, a diallyl phthalate resin, a urea resin, a polyester resin etc. are contained in the example of a thermosetting resin. The sealing material for display elements may contain only 1 type of thermosetting resin, and may contain it 2 or more types.

The sealing material for display elements may contain the filler. Glass beads, styrenic polymer particles, methacrylate-based polymer particles, ethylene-based polymer particles, propylene-based polymer particles, and the like are included in the example of the filler contained in the sealing material for display elements. The sealing material for display elements may contain only 1 type, and may contain it 2 or more types.

The sealing material for display elements may contain the modifier and the stabilizer. Specific examples of the modifier include antioxidants, leveling agents, wettability improvers, surfactants, plasticizers, and the like. These modifiers can be used individually by 1 type or in combination of 2 or more type. On the other hand, specific examples of the stabilizer include ultraviolet absorbers, preservatives, antibacterial agents, and the like. The sealing material for display elements may contain 1 type, and may contain 2 or more types of these modifiers and stabilizers.

The sealing material for display elements may contain the antioxidant. Antioxidant means a thing which deactivates the radical which generate|occur|produces by plasma irradiation or sunlight irradiation (Hindered Amine Light Stabilizer, HALS), a thing which decomposes|disassembles a peroxide, etc. Antioxidant has a function which prevents discoloration of the hardened|cured material of the sealing material for display elements. Examples of antioxidants include hindered amines, phenolic antioxidants, phosphorus antioxidants, and the like.

Examples of hindered amines include bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate, 2,4-dichloro-6-tert-octylamino-s-triazine and 4,4 polycondensation product of '-hexamethylenebis(amino-2,2,6,6-tetramethylpiperidine), bis[1-(2-hydroxy-2-methylpropoxy)-2,2,6, 6-tetramethylpiperidin-4-yl]sebacate.

Examples of the phenolic antioxidant include monophenols such as 2,6-di-t-butyl-p-cresol, bisphenols such as 2,2'-methylenebis(4-methyl-6-t-butylphenol); and polymeric phenols such as 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane.

Examples of the phosphorus antioxidant include antioxidants selected from phosphites and color inhibitors selected from oxaphosphaphenanthrene oxides.

In particular, in terms of imparting resistance to ultraviolet rays, Tinuvin 123 (bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacic acid), Tinuvin 765 (bis (1, Mixture of 2,2,6,6-pentamethyl-4-piperidyl)sebacic acid and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacic acid), Hostavin PR25 (dimethyl 4 -Methoxybenzylidenemalonate), Tinuvin 312 or Hostavin vsu (ethanediamide N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)), CHIMASSORB 119 FL (N,N'-bis( 3-Aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-6-chloro-1,3 ,5-triazine condensates) are preferred.

The sealing material for display elements may contain the solvent as needed. The solvent has a function of uniformly dispersing or dissolving each component. Examples of the solvent include aromatic solvents such as toluene and xylene; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ethers such as ether, dibutyl ether, tetrahydrofuran, dioxane, and ethylene glycol monoalkyl ether; aprotic polar solvents such as N-methylpyrrolidone; Esters, such as ethyl acetate and butyl acetate, etc. are contained.

(G) Physical properties of sealing material for display elements, etc.

The viscosities measured at 25 degreeC and 2.5 rpm of the sealing material for display elements of this invention with an E-type viscometer are 5 mPa*s or more and 400 mPa*s or less, and it is preferable that they are 5-200 mPa*s. When the viscosity of the sealing material for display elements is the said range, the fluidity|liquidity at the time of sealing various display elements will become sufficient easily. The said viscosity can be measured, for example with the digital rheometer type|mold DII-III ULTRA by a Brookfield company.

By adjusting content of each component contained in the sealing material for display elements, the viscosity of the sealing material for display elements can be adjusted to the said range. Moreover, adjusting the weight average molecular weight of the (A) aliphatic (meth)acryl monomer and (A-2) ring structure containing (meth)acryl monomer is also effective in order to adjust the viscosity of the sealing material for display elements to the said range.

Moreover, the glass transition temperature (Tg) of the hardened|cured material obtained by heating the sealing material for display elements at 100 degreeC for 30 minutes is 46 degreeC or more as mentioned above, It is preferable that it is 46-100 degreeC, and it is more preferable that it is 46-80 degreeC. do.

On the other hand, it is preferable that the linear expansion coefficients in 35 degreeC - 100 degreeC of the hardened|cured material of the sealing material for display elements are 50 or more and 250 or less, It is more preferable that it is 80-250 ppm/degreeC, It is still more preferable that it is 100-200 ppm/degreeC. When the linear expansion coefficient of the hardened|cured material of the sealing material for display elements is the said range, it becomes difficult for the sealing material for display elements to shrink|contract at the time of the hardening or after hardening, and it becomes difficult to generate|occur|produce the above-mentioned stripe unevenness. For the coefficient of linear expansion of the cured product of the sealing material for display elements, thermal analysis was performed at a temperature increase rate of 5° C./min with a thermomechanical analyzer (TMA apparatus) or the like for a cured product obtained by heating the sealing material for display elements at 100° C. for 30 minutes. It is a value that is specified by performing

The sealing material for the display element includes (A) an aliphatic (meth)acrylic monomer, (B) an azo polymerization initiator, (C) a tetramethylpiperidine free radical derivative, and (D) a silane coupling agent, and, if necessary, other It can manufacture by mixing components ((A-2) ring structure containing (meth)acryl monomer etc.) by a well-known method. Although the mixing order is not particularly limited, for example, (A) an aliphatic (meth)acryl monomer or (A-2) a (meth)acryl monomer containing a ring structure, (C) a tetramethylpiperidine free radical derivative or (D ) After dissolving the silane coupling agent, it is preferable to mix the (B) azo polymerization initiator.

(H) Use of sealing material for display elements

The sealing material for display elements of this invention is used in order to seal various display elements. An inorganic LED (Light Emitting Diode) element, a liquid crystal element, organic electroluminescent element etc. are contained in the example of various display elements, Preferably it is an organic electroluminescent element. By sealing various display elements with the sealing material for display elements mentioned above, it is suppressed that these display elements deteriorate by water|moisture content etc.

As mentioned above, the sealing material for display elements of this invention is good also as a surface sealing material for surface sealing various display elements, and good also as a frame sealing material for frame sealing. For example, after apply|coating a liquid sealing material for display elements on to-be-sealed object (display element side board|substrate or a display element), by making a display element side board|substrate and a sealing substrate oppose and hardening the sealing material for display elements, etc. , the display element can be surface-sealed. In this case, the sealing material for display elements can be apply|coated by the screen printing method, the inkjet printing method, dispenser application|coating, etc.

Moreover, the sealing material for display elements may be shape|molded previously in the form of a film, and you may laminate the said film on to-be-sealed object (a board|substrate or a display element). In this case, a sealing substrate is further mounted on the sealing material for display elements on a film, and the sealing material for display elements is hardened. Thereby, a display element can be surface-sealed.

The sealing material for display elements of this invention can be used in an oxygen-free environment and 40 degrees C or less. And even if it uses in such an environment, it is hard to volatilize the component in the sealing material for display elements, and there are few changes in a viscosity.

In addition, hardening of the said sealing material for display elements can be performed by heating. The heating temperature is appropriately set and is appropriately set in consideration of the heat resistance temperature and efficiency of the object to be sealed, but can be usually 80 to 130°C, preferably 90 to 110°C. According to the sealing material for display elements of this invention, even if it heats at the said temperature, it is hard to generate|occur|produce the outgas which affects a display element during hardening and after hardening. Moreover, since it is hard to generate|occur|produce streaked nonuniformity in the hardened|cured material obtained, the high-quality display apparatus excellent also in external appearance is obtained.

Example

Hereinafter, the present invention will be described with reference to Examples. The examples are not construed as limiting the scope of the present invention.

[ingredient]

In Examples and Comparative Examples, the following materials were used.

(A) aliphatic (meth)acrylic monomer

9PG: polypropylene glycol #400 dimethacrylate represented by the following formula (Molecular weight 536 manufactured by Shin-Nakamura Chemical Co., Ltd.)

TMPT-3EO: EO-modified trimethylolpropane trimethacrylate represented by the following formula (Molecular weight 470 manufactured by Shin-Nakamura Chemical Co., Ltd.)

FA-137M: EO-modified trimethylolpropane trimethacrylate represented by the following formula (Molecular weight 1263 manufactured by Hitachi Chemical)

(A-2) Ring structure-containing (meth)acrylic monomer

BPE-500: ethoxylated bisphenol A dimethacrylate represented by the following formula (Molecular weight 804 manufactured by Shin-Nakamura Chemical Co., Ltd.)

DCP: tricyclodecanemethanol dimethacrylate represented by the following formula (Molecular weight 332 manufactured by Shin-Nakamura Chemical Co., Ltd.)

(B) azo polymerization initiator

OTAZO: 1,1'-azobis-(1-acetoxy-1-phenylethane) represented by the following formula (Otsuka Chemical Co., Ltd. molecular weight 354.4, melting point 106-110°C, decomposition point 106-110°C, 10 hours Half-life temperature 61°C)

(C) tetramethylpiperidine free radical derivatives

4H-TEMPO: 4-hydroxy-2,2,6,6-tetramethylpiperidine1-oxyl free radical represented by the formula

(D) Silane coupling agent

X-12-1048: organic chain type polyfunctional silane coupling agent (manufactured by Shin-Etsu Silicone, viscosity 33 mm2/s, reactive functional group equivalent 300 g/mol, molecular weight 2,500 (estimated))

·X-12-1050: organic chain type polyfunctional silane coupling agent (manufactured by Shin-Etsu Silicone, viscosity 6,000 mm2/s, reactive functional group equivalent 150 g/mol, molecular weight 140,000 (estimated))

X-40-9296: siloxane chain type polyfunctional silane coupling agent (manufactured by Shin-Etsu Silicone, viscosity 20 mm 2 /s, reactive functional group equivalent 230 g/mol, molecular weight 1,500 (estimated))

·KBM-5103: 3-acryloxypropyltrimethoxysilane represented by the following formula (manufactured by Shin-Etsu Silicone, molecular weight 258)

(E) leveling agent

・LS-460 (manufactured by Kusumoto Kasei)

[Example 1]

(A) as an aliphatic (meth)acrylic monomer, 9PG 45g, TMPT-3EO 10g, (A-2) as a ring structure-containing (meth)acrylic monomer, BPE-500 45g, (C) a tetramethylpiperidine free radical derivative 0.03 g of 4H-TEMPO, and (D) 3 g of X-12-1048 as a silane coupling agent were mixed and stirred. Then, 0.3 g of OTAZO was added as (B) azo-type polymerization initiator, it mixed and stirred further, and the sealing material for display elements was prepared.

[Examples 2 to 6, and Comparative Examples 1 to 7]

Except having set it as the material and composition shown in Table 1 and Table 2, it carried out similarly to Example 1, and prepared the sealing material for display elements.

[evaluation]

The viscosity of the sealing material for display elements prepared in each Example and the comparative example was measured. In addition, the following method performed the measurement of the glass transition temperature (Tg) of hardened|cured material, the measurement of the linear expansion coefficient of hardened|cured material, confirmation of the streaked unevenness after hardening, and evaluation of adhesive strength. The results are shown in Tables 1 and 2.

・Viscosity measurement

The viscosity of the sealing material for display elements in 25 degreeC and 2.5 rpm was measured with the E-type viscometer (DII-III ULTRA of the digital rheometer type|mold by BROOKFIELD company).

Glass transition temperature (Tg) and coefficient of linear expansion of the cured product

The sealing material for display elements was heated and hardened by conditions 100 degreeC for 30 minute(s). The cured sample was cut out to 50 mm in length x 4 mm in width, and it measured with the TMA measuring apparatus (TMA SS6000 Seiko Instruments company make) at the temperature increase rate of 5 degree-C/min. And Tg and the coefficient of linear expansion in 35 degreeC - 100 degreeC were specified by analysis software.

・Confirmation of streaks after curing

(How to make the sample)

An appropriate amount of the sealing material for display elements was mounted on the alkali free glass of 25 mm x 45 mm x thickness 0.7 mm, it put in the vacuum chamber, and pressure-reduced to 1.2 Pa with the vacuum pump. Thereafter, spacers having a thickness of 15 µm and a width of 5 mm were placed on both ends of the glass. In the evaluation sample, a spacer was used instead of the dam material. And the alkali-free glass (25 mm x 45 mm x thickness 0.7 mm) of the same size as the above was mounted from the top of the said spacer. Then, both ends were pinched with clips and the sealing material was spread between the opposing glasses. The said glass laminated body was heated at 100 degreeC for 30 minute(s) in nitrogen purge oven (DN4101 made from Yamato Chemical), and the sealing material for display elements was hardened.

(Evaluation of streaked blotches)

The vicinity of the interface between the spacer of the glass laminate and the sealing material was confirmed from the glass surface side under a microscope, and it evaluated as follows. In addition, the photograph of the sample (hardened|cured material 12 of the sealing material for display elements near the spacer 13) produced in Example 1 and Comparative Example 1 is shown to FIG. 2A and FIG. 2B, respectively.

No staining: A

Spots occur in the range of 500 µm or less in width from the interface: B

Smudges occur from the interface to a range greater than 500 μm in width: C

・Evaluation of adhesive strength

The tweezers were inserted between the glass and the glass of the glass laminated body produced by the confirmation of the above-mentioned stripe nonuniformity, and the peeling interface was confirmed as follows. In addition, it can be said that the adhesive strength is higher in the direction in which the sealing material for display elements is destroyed or glass cracks rather than peeling at the interface of glass and the hardened|cured material of the sealing material for display elements.

In case of peeling between glass and sealing material for display element: △ (interfacial peeling)

If the glass breaks: ○ (material destruction)

As shown in Table 1 and FIG. 2A, (A) an aliphatic (meth)acrylic monomer, (B) an azo polymerization initiator, (C) a tetramethylpiperidine free radical derivative, (D) (meth)acryl In the sealing material for display elements which has a group and contains the silane coupling agent whose molecular weight is 400-500,000, and the glass transition temperature after hardening is 46 degreeC or more (Examples 1-6). (D) The silane coupling agent is difficult to volatilize even in a vacuum environment, the adhesiveness between the cured product of the sealing material and the glass substrate is very high, and the sealing material (or its cured product) is difficult to deform during or after curing, etc. It is thought that it was difficult to generate|occur|produce the gap|interval (stripe nonuniformity) between the hardened|cured material of the sealing material for display elements, and glass.

In addition, as shown in Table 1, when the trifunctional (A) aliphatic (meth)acryl monomer was contained together with the (D) silane coupling agent, the adhesive strength was particularly easy to increase (Examples 1, 2, 5, and 6).

On the other hand, as shown in Table 2 and FIG. 2B, when the (D) silane coupling agent described above is not included (Comparative Examples 1 and 2) or when the molecular weight is less than 400 (Comparative Example 3), the glass substrate and Not only did the adhesive strength of the sealing material not increase, but also striped spots were generated. Moreover, even if the above-mentioned component (A)-(D) was contained, when the glass transition temperature after hardening of the sealing material for display elements was less than 46 degreeC (Comparative Examples 4-7), it was easy to generate|occur|produce a streaked nonuniformity. When a glass transition temperature is low, it is estimated that the hardened|cured material of the sealing material for display elements will deform|transform or shrink easily after hardening, and it will be easy to generate|occur|produce a streaked nonuniformity.

This application claims priority based on Japanese Patent Application No. 2018-050955 for which it applied on March 19, 2018. All content described in the said application specification and drawing is integrated in this specification.

Not only can the sealing material for display elements of this invention fully seal a display element, but it is hard to generate|occur|produce a streaked nonuniformity after sealing. Therefore, it is applicable to various display elements.

11: Dam material
12: Hardened|cured material of the sealing material for display elements
13: spacer

Claims (14)

(A) an aliphatic (meth)acrylic monomer having a weight average molecular weight of 400 or more and 2000 or less;
(B) an azo polymerization initiator;
(C) a 2,2,6,6-tetramethylpiperidine 1-oxyl free radical derivative represented by the following general formula (1);
(D) a silane coupling agent having a (meth)acryl group and having a weight average molecular weight of 400 to 500,000
including,
The glass transition temperature of the cured product obtained by heating at 100° C. for 30 minutes is 46° C. or higher,
A sealing material for display elements.

(In the general formula (1), R is H, a hydroxyl group, an oxo group, an amino group, a cyano group, an acetamide group, a methoxy group, a carboxy group, a palmitamide group, a methacryloyl group, an isothiocyanate group, 2-chloro selected from the group consisting of an acetamide group, a 2-iodoacetamide group, a (9-acridinecarbonyl)amino group, and a [2-[2-(4-iodophenoxy)ethoxy]carbonyl]benzoyl group represents any one group that becomes The method of claim 1, wherein the (D) silane coupling agent comprises two or more (meth)acryl groups in a molecule,
A sealing material for display elements. The method according to claim 1 or 2, wherein the (D) silane coupling agent contains two or more Si atoms in a molecule.
A sealing material for display elements. According to claim 1 or 2, wherein the (D) silane coupling agent comprises a siloxane bond in the main chain,
A sealing material for display elements. The cured product according to claim 1 or 2, wherein the cured product obtained by heating at 100°C for 30 minutes has a coefficient of linear expansion at 35°C to 100°C of 50 or more and 250 or less,
A sealing material for display elements. The said (A) aliphatic (meth)acryl monomer contains 5-50 mass % of trifunctional or more than trifunctional (meth)acryl monomers, according to claim 1 or 2,
A sealing material for display elements. delete The said (A) aliphatic (meth)acryl monomer is a methacryl monomer according to claim 1 or 2,
A sealing material for display elements. The method according to claim 1 or 2, further comprising (A-2) a ring structure-containing (meth)acryl monomer.
A sealing material for display elements. The said (A-2) ring structure containing (meth)acryl monomer contains the structure of bisphenol A type according to claim 9,
A sealing material for display elements. According to claim 1 or 2, further comprising a leveling agent,
A sealing material for display elements. It contains the sealing material for display elements of Claim 1 or 2 and is used for frame sealing of an organic electroluminescent element,
Frame sealing material for organic EL devices. It contains the sealing material for display elements of Claim 1 or 2, and is used for surface sealing of an organic electroluminescent element,
Surface sealant for organic EL devices. Hardened|cured material of the sealing material for display elements of Claim 1 or 2.

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