JP4478116B2 - Adhesive for sealing organic electroluminescent element, adhesive tape for sealing organic electroluminescent element, double-sided adhesive tape for sealing organic electroluminescent element, sealing method for organic electroluminescent element, and organic electroluminescent element - Google Patents

Description

The present invention relates to an organic electroluminescent element sealing adhesive, an organic electroluminescent element sealing adhesive tape, and an organic electroluminescent element sealing that can seal an organic electroluminescent element without being deteriorated by light or heat. The present invention relates to a double-sided pressure-sensitive adhesive tape, an organic electroluminescence element sealing method, and an organic electroluminescence element.

An electroluminescent element (hereinafter referred to as an organic EL element) using an organic electroluminescent material (hereinafter referred to as an organic EL material) for a light emitting layer is usually formed on a single electrode provided on a substrate, a hole injection layer, The light-emitting layer and the electron injection layer are sequentially laminated, and further comprise a thin film structure in which another electrode is provided thereon. FIG. 1 is a sectional view schematically showing an example of such a thin film structure. A thin film structure 20 shown in FIG. 1 includes a hole injection electrode composed of an anode 2, a hole injection layer 3 and a hole transport layer 4, an organic thin film 5 (light emitting layer), and an electron injection layer on a substrate 1. 6 and an electron injection electrode composed of a cathode 7 are sequentially stacked. The structure of the thin film structure is not limited to the structure shown in FIG. 1. For example, the organic thin film 5 may be formed at least between the anode 2 and the cathode 7, but the performance of the device is improved. Therefore, a structure in which the hole injection layer 3, the hole transport layer 4, and the electron injection layer 6 are formed as in the thin film structure 20 shown in FIG. 1 is preferable.
An organic EL element composed of such a thin film structure is self-luminous and has good visibility, and since it is a solid element, it has excellent impact resistance and is attracting attention as a means for realizing a DC low-voltage driving element.

In the past, organic EL devices have problems that impede practicality such as lack of long-term storage reliability (lifetime) compared to inorganic thin film devices (organic dispersed inorganic EL devices) such as ZnS: Mn inorganic thin film devices. Had. However, in recent years, improvements in organic materials for forming organic thin film layers, improvements in cathode metal materials, and passivation (gas barrier films) have progressed, and the characteristics have been improved in environmental reliability tests. It has been reported that the half-life of time exceeds 10,000 hours.

However, organic thin films (light-emitting layers) constituting organic EL elements, light-emitting materials that are materials for hole injection layers and electron injection layers, and organic solids such as hole injection materials and electron injection materials are affected by moisture, oxygen, and the like. The problem of being easily done is not completely solved. In addition, since the characteristics of the counter electrodes provided above and below the organic solid are deteriorated by oxidation, the light emission characteristics are rapidly deteriorated when the organic EL element is driven in the atmosphere. Therefore, in order to obtain a practical organic EL element, the organic solid and the counter electrode are shielded from the atmosphere so that moisture and oxygen do not enter the organic solid and the counter electrode is not oxidized. It is necessary to plan.

As a method for blocking the organic solid and the counter electrode from the atmosphere, for example, Patent Document 1 discloses a method in which a thin film structure portion is sealed with an airtight container such as metal or glass, and a desiccant is further placed inside the airtight container. It is disclosed. Patent Document 2 discloses a method of covering the surface of a thin film structure with a protective film of silicon oxide or silicon nitride, and Patent Document 3 discloses a method of coating a metal electrode with an ultraviolet curable resin. Patent Document 4 discloses a method of forming an inorganic film and an organic film in multiple layers and blocking them from the atmosphere. Patent Document 5 discloses a moisture-proof polymer film and thermosetting. A method of shielding from the atmosphere by a sealing film composed of an adhesive layer is disclosed, and in Patent Document 6, in a top emission organic EL element or the like, a photocurable adhesive is filled between organic EL element substrates. A method of sealing by irradiating light is disclosed.

However, the method of sealing with an airtight container has a problem that the thickness is increased and the weight is increased by providing the airtight container. In addition, the method of covering with a protective film of silicon oxide or silicon nitride does not cause scratches due to collision of objects during repair of the element (burning the defective element with a laser or the like to make it open) or during manufacturing operations. In order to prevent this, it is necessary to increase the film thickness. However, if the film thickness is increased, the residual stress increases and the substrate is warped, cracks occur and the characteristics are deteriorated, and if the film thickness is increased, the film formation time is increased. There was a problem of becoming longer.

In addition, when sealing with a photo-curable adhesive or a thermosetting adhesive, when the adhesive is cured, the performance of the element is likely to deteriorate because the organic EL element is directly exposed to heat or light, In some cases, there was a problem of deterioration. In addition, when a photo-curable adhesive is used, the gas generated during light irradiation fills the element and promotes deterioration of the element, or there is a part that is not exposed to light due to metal wiring or UV light. When sealing a substrate containing an absorbent, there is a problem that the curing of the photocurable adhesive may be insufficient.
Japanese Patent Laid-Open No. 9-148066 JP-A-8-111286 JP 7-192867 A JP 2000-223264 A Japanese Patent Application Laid-Open No. 5-101884 JP 2001-357773 A

The present invention relates to an organic electroluminescent element sealing adhesive, an organic electroluminescent element sealing adhesive tape, and an organic electroluminescent element sealing that can seal an organic electroluminescent element without being deteriorated by light or heat. It aims at providing a double-sided adhesive tape, the sealing method of an organic electroluminescent element, and an organic electroluminescent element.

The first invention of the present invention contains a photocationic polymerizable compound and a photocationic polymerization initiator, initiates a curing reaction upon irradiation with light, and undergoes a curing reaction by a dark reaction even after blocking light. It is an adhesive for sealing an organic electroluminescence element made of an adhesive.

The cationic photopolymerizable compound is preferably an aromatic epoxy resin. In addition, the photocationic polymerization initiator is preferably a salt having a boronic acid represented by the following formula (1) as a counter ion.

Further, the above cationic photopolymerization initiator is a reaction product of a compound having at least one hydroxyl group in the molecule and generating an acid by light irradiation and a compound having two or more functional groups that react with the hydroxyl group in the molecule. The above is preferable, and a reaction product of a compound having two or more hydroxyl groups in the molecule and generating an acid upon irradiation with light and a carboxylic anhydride or dicarboxylic acid is more preferable.

The photocationically polymerizable adhesive preferably contains an aliphatic hydrocarbon having a hydroxyl group and / or a polyether compound, preferably contains a filler, and contains an alkaline filler and / or an acid that reacts with an acid. It preferably contains an adsorbing ion exchange resin, and preferably contains a desiccant.

A method for sealing an organic electroluminescent element using the organic electroluminescent element sealing adhesive according to the first aspect of the present invention, wherein the organic electroluminescent element sealing adhesive is irradiated with light, and then the organic There is also a method for sealing an organic electroluminescent element that fills and seals the organic electroluminescent element sealing adhesive between the sealing plate and the thin film structure until the electroluminescent element sealing adhesive is cured. Moreover, it is one of the present inventions. A method for sealing an organic electroluminescent element using the organic electroluminescent element sealing adhesive according to the first aspect of the present invention, wherein the organic electroluminescent element sealing adhesive is irradiated with light, and then the organic Before the electroluminescent element sealing adhesive is cured, the organic electroluminescent element sealing adhesive is applied so as to seal the periphery of the thin film structure, and the sealing plate is attached to seal the organic electro A method for sealing a luminescent element is also one aspect of the present invention.

The second aspect of the present invention is an organic electroluminescent element sealing comprising a moistureproof tape and an adhesive layer made of the adhesive for sealing an organic electroluminescent element of the first aspect of the present invention formed on at least one surface of the moistureproof tape. This is an adhesive tape for fastening. The pressure-sensitive adhesive layer preferably has a moisture permeability of 30 g / m ² · 24 h / 100 μm or less measured by a moisture-permeable cup method in accordance with JIS Z 0208 under conditions of 60 ° C. and 90% RH. It is preferable that the adhesive layer has a sheet-like desiccant.

A method for sealing an organic electroluminescent device using the adhesive tape for sealing an organic electroluminescent device of the second aspect of the present invention, wherein the adhesive layer of the adhesive tape for sealing an organic electroluminescent device is irradiated with light The method for sealing an organic electroluminescent element in which the adhesive layer is stuck and sealed on the thin film structure before the adhesive layer is cured is also one aspect of the present invention.

3rd this invention is a double-sided adhesive for organic electroluminescent element sealing which has the adhesion layer which consists of the adhesive agent for organic electroluminescent element sealing of 1st this invention, and the separator formed in both surfaces of the said adhesion layer. It is a tape. The pressure-sensitive adhesive layer preferably has a moisture permeability of 30 g / m ² · 24 h / 100 μm or less measured by a moisture-permeable cup method in accordance with JIS Z 0208 under conditions of 60 ° C. and 90% RH.

A method for sealing an organic electroluminescence element using the adhesive tape for sealing an organic electroluminescence element of the third invention, wherein one separator of the double-sided adhesive tape for sealing an organic electroluminescence element is peeled off, Paste the double-sided pressure-sensitive adhesive tape for sealing the organic electroluminescence element so as to seal the periphery of the thin film structure between the time when the pressure-sensitive adhesive layer on the side where the separator is peeled off is irradiated with light until the pressure-sensitive adhesive layer is cured. The organic electroluminescence device sealing method of peeling the other separator of the double-sided pressure-sensitive adhesive tape for sealing the organic electroluminescence device and further covering the sealing layer with a sealing plate is also provided in the present invention. It is one of.

Adhesive for sealing an organic electroluminescence element of the first invention, Adhesive tape for sealing an organic electroluminescence element of the second invention, or Double-sided adhesive tape for sealing an organic electroluminescence element of the third invention An organic electroluminescence element sealed with is also one aspect of the present invention.
The present invention is described in detail below.

The adhesive for sealing an organic electroluminescence element of the first aspect of the present invention (hereinafter also referred to as an adhesive for sealing an organic EL element) starts a curing reaction upon irradiation with light, and is a dark reaction even after blocking light. It consists of a photocationically polymerizable adhesive that undergoes a curing reaction. By comprising such a cationic photopolymerizable adhesive, for example, the organic EL element sealing adhesive of the first invention is applied to a sealing plate for sealing the organic EL element, and the adhesive is applied to the adhesive. After activating the adhesive by irradiating light, the light can be blocked, the sealing plate and the thin film structure can be bonded together to seal the organic EL element, and the organic EL element is not exposed to heat or light Can be sealed.

The adhesive for sealing an organic EL element of the first aspect of the present invention preferably has a usable time of 1 minute or longer after irradiation with light until the curing reaction proceeds and adhesion cannot be performed. If it is less than 1 minute, curing proceeds before sealing the light emitting layer, and sufficient adhesive strength may not be obtained.

The cationic photopolymerizable adhesive contains at least a cationic photopolymerizable compound and a cationic photopolymerization initiator.
The photocationically polymerizable compound is not particularly limited as long as it is a compound having at least one photocationically polymerizable functional group in the molecule. Examples of the photocationically polymerizable functional group include compounds having a functional group such as an epoxy group, an oxetane group, a hydroxyl group, a vinyl ether group, an episulfide group, and an ethyleneimine group. Among these, an epoxy group-containing compound having at least one epoxy group in the molecule and exhibiting high adhesion and durability after curing is preferable.

Although it does not specifically limit as said epoxy-group containing compound, Aromatic epoxy resin is suitable. Of these, phenoxy resin is more preferable.

The phenoxy resin is not particularly limited, but those having a weight average molecular weight of 50,000 to 100,000 and an epoxy equivalent of 7,000 to 10,000 are suitable. Examples of such commercially available phenoxy resins include “Epicoat 1256”, “Epicoat 4250”, “Epicoat 4275”, “Epicoat 1255HX30” (manufactured by Japan Epoxy Resin Co., Ltd.); “YP-50S” (Made by Tohto Kasei Co., Ltd.).

Examples of the aromatic epoxy resin other than the phenoxy resin include a TBBPA type such as that represented by the following formula (2), a trifunctional type such as that represented by the following formula (3), a biphenyl type, and a naphthalene type. Phenol novolak type, cresol novolak type, dicyclopentadiene type, tetraphenylolethane type and the like.

Other examples of the epoxy group-containing compound include addition polymers of epoxy group-containing monomers and epoxy group-containing oligomers, for example, epoxy groups such as epoxy group-containing polyester resins, epoxy group-containing polyurethane resins, and epoxy group-containing acrylic resins. Containing resin and the like. At this time, a flexible epoxy resin can be used in order to impart an appropriate flexibility to the cured resin.
These epoxy group-containing compounds may be used alone or in combination of two or more.

The photocationic polymerization initiator may be an ionic photoacid generation type or a nonionic photoacid generation type.

Examples of the ionic photoacid-generating photocationic polymerization initiator include onium salts such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts; iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes. And the like, and the like.

Among these, the cationic photopolymerization initiator composed of a salt having a bulky boronic acid represented by the following formula (1) as a counter ion is not easily oxidized at the interface between the electrode and the adhesive, and has excellent durability. Therefore, it is preferable.

As what is marketed among such photocationic polymerization initiators, for example, “PI-2074” (manufactured by Rhone Plan) represented by the following formula (4), and represented by the following formula (5): Examples thereof include “TAG-371R” (manufactured by Toyo Ink Co., Ltd.), “TAG-372R” (manufactured by Toyo Ink Co., Ltd.) represented by the following formula (6), and the like.

In addition, since the cationic photopolymerization initiator containing iodine can absorb light having a long wavelength, it can be expected that the polymerization start wavelength can be set to the long wavelength side. On the other hand, the obtained polymer may be colored. . In this case, it is preferable to use a photocationic polymerization initiator represented by the following formulas (7) to (9) because the polymerization start wavelength can be made longer without coloring.

The nonionic photoacid generation type photocationic polymerization initiator is not particularly limited, and examples thereof include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester, diazonaphthoquinone, N-hydroxyimidosulfonate, and the like. Is mentioned.

As the photocationic polymerization initiator, it is preferable to use one having a high molecular weight or a large amount. After the photocationic polymerization initiator generates acid and initiates cationic polymerization, the residue may be outgassed to deteriorate the device. As a result of intensive studies, the present inventors have found that generation of outgas can be suppressed by using a photocationic polymerization initiator having a high molecular weight or a large amount.

The method for increasing the molecular weight or increasing the amount of the photocationic polymerization initiator is not particularly limited. For example, a compound having at least one hydroxyl group in the molecule and generating an acid by light irradiation, and a hydroxyl group in the molecule Reaction product of a compound having two or more functional groups that react with each other, more preferably a compound having two or more hydroxyl groups in the molecule and generating an acid upon irradiation with a carboxylic anhydride or dicarboxylic acid A method in which the product is used as a photocationic polymerization initiator is preferred.

Examples of commercially available compounds having at least one hydroxyl group in the molecule and generating an acid upon irradiation with light include “CD-1012” manufactured by Sartomer Co., which has an iodonium salt skeleton.

In addition, examples of the functional group that reacts with a hydroxyl group in the molecule include a carboxyl group and an isocyanate group, and the compound having two or more functional groups that react with a hydroxyl group in the molecule is not particularly limited. Acids or dicarboxylic acids are preferred. Examples of the carboxylic anhydride include phthalic anhydride and maleic anhydride. Examples of the dicarboxylic acid include fatty acids such as succinic acid, glutaric acid and adipic acid; phthalic acid and terephthalic acid. And aromatic acids such as isophthalic acid.
These cationic photopolymerization initiators may be used alone or in combination of two or more.

Although it does not specifically limit as a compounding quantity of the said photocationic polymerization initiator in the said photocationic polymerizable adhesive, 0.1-10 weight part is preferable with respect to 100 weight part of the said photocationic polymerizable compounds. If the amount is less than 0.1 parts by weight, the photocationic polymerization may not proceed sufficiently, or the reaction may become too slow. If the amount exceeds 10 parts by weight, the reaction becomes too fast and the workability decreases. Or the reaction may become uneven.

The cationic photopolymerizable adhesive preferably further contains an aliphatic hydrocarbon having a hydroxyl group and / or a polyether compound. Since the aliphatic hydrocarbon or polyether compound having a hydroxyl group inhibits the photocationic polymerization reaction of the photocationic polymerizable adhesive, the usable time after light irradiation and the curing time can be reduced by adding an appropriate amount. It plays a role as a controlled reaction regulator and can greatly improve workability.

Examples of the aliphatic hydrocarbon having a hydroxyl group include polyfunctional hydroxyl group-containing compounds such as glycerin and pentaerythritol. Examples of the polyether compound include polyethylene glycol, polypropylene glycol, and polyoxytetramethylene glycol. Examples include polyalkylene oxide. Of these, polyalkylene oxide is preferably used, and polyoxytetramethylene glycol is particularly preferably used.

The terminal of the polyalkylene oxide is not particularly limited, and may be a hydroxyl group, may be etherified or esterified with another compound, or may be a functional group such as an epoxy group. Etc. are preferably used because they react with the cationically polymerizable compound.

As the polyether compound, a polyalkylene oxide-added bisphenol derivative is also preferably used, and a compound having a terminal hydroxyl group or epoxy group is particularly preferably used. Among these, examples of commercially available products include Rica Resin BPO-20E, Rica Resin BEO-60E, Rica Resin EO-20, and Rica Resin PO-20 (all manufactured by Shin Nippon Rika Co., Ltd.).

The amount of the aliphatic hydrocarbon and / or polyether compound having a hydroxyl group in the photocationic polymerizable adhesive is not particularly limited, and is appropriately determined according to the required usable time and curing time. Although added, generally 1-30 weight part is preferable with respect to 100 weight part of said photocationic polymerizable compounds, and 5-20 weight part is more preferable.

The cationic photopolymerizable adhesive preferably further contains an alkaline filler that reacts with an acid and / or an ion exchange resin that adsorbs the acid. When the above cationic photopolymerizable adhesive undergoes cationic photopolymerization, an acid may be generated to corrode the electrode. However, it contains an alkaline filler that reacts with the acid and / or an ion exchange resin that adsorbs the acid. Thus, the durability of the element electrode can be improved. The alkaline filler that reacts with the acid is not particularly limited as long as it is a substance that can be neutralized with an acid. For example, an alkaline metal or alkaline earth metal such as calcium carbonate, calcium hydrogen carbonate, sodium carbonate, or sodium hydrogen carbonate is used. Examples thereof include carbonates and hydrogen carbonates. As the ion exchange resin that adsorbs the acid, any of a cation exchange type, an anion exchange type, and a both ion exchange type can be used, and in particular, a cation exchange type that can adsorb chloride ions. It is preferable to use a both ion exchange type.

The photocationically polymerizable adhesive preferably further contains a filler. By containing the filler, moisture permeability, adhesive strength, curing shrinkage, coefficient of thermal expansion, and the like can be improved. The filler is not particularly limited. For example, powders such as colloidal silica, talc, mica, calcium carbonate, titanium oxide, and clay; inorganic hollow bodies such as glass balloons, alumina balloons, and ceramic balloons; nylon beads, acrylic beads And organic spherical bodies such as silicon beads and fluororesin beads; organic hollow bodies such as vinylidene chloride balloons and acrylic balloons; single fibers such as glass, polyester, rayon, nylon and cellulose.

However, when sealing is performed so as to cover the surface of the thin film structure using the organic EL element sealing adhesive of the first invention, it is necessary that the adhesive has high transparency. The filler is preferably transparent, and the blending amount is preferably minimized. Since the adhesive for sealing an organic EL device of the first invention can be designed so that the reaction proceeds in a dark reaction even after light irradiation and the reaction proceeds slowly over at least several hours, light is irradiated in advance. If the organic EL element is sealed after being partially cured, the sealing can be reliably performed without containing a filler.

It is preferable that the photo cationic polymerizable adhesive further contains a desiccant. The desiccant is not particularly limited, and examples thereof include oxides of alkaline earth metals such as silica gel, molecular sieve, calcium oxide, barium oxide, and strontium oxide.

When using the said photocationic polymerizable adhesive as an adhesive layer of the adhesive tape mentioned later, it is preferable that the said photocationic polymerizable adhesive contains an adhesive resin further. The adhesive resin is not particularly limited as long as it can provide the adhesive layer with adhesiveness at normal temperature and sheet cohesion, and examples thereof include epoxy resins, acrylic polymers, polyesters, polyurethanes, Examples include silicones, polyethers, polycarbonates, polyvinyl ethers, polyvinyl chlorides, polyvinyl acetates, polyisobutylenes and the like. The adhesive resin may be a copolymer containing a monomer that is a main component of these resins. Among them, an acrylic resin or a polyester resin is preferable because it exhibits excellent initial adhesive force and easy control of adhesive properties.

The above-mentioned photo-cationic polymerizable adhesive may further contain various additives such as an adhesion improver, a reinforcing agent, a softener, a plasticizer, and a viscosity modifier as necessary.

It does not specifically limit as a manufacturing method of the organic EL element sealing adhesive of 1st this invention, For example, using mixers, such as a homodisper, a homomixer, a universal mixer, a planetarium mixer, a kneader, and a three roll. And a method of mixing each predetermined amount of a photocationic polymerizable compound, a photocationic polymerization initiator, and other blends at room temperature or under heating. In addition, it is preferable to manufacture in the state which interrupted | blocked light.

The adhesive for sealing an organic EL element according to the first aspect of the present invention is activated by irradiation with light, since the curing reaction starts by light irradiation and the curing reaction proceeds by dark reaction even after blocking light. If it is used until it is completely cured, the organic EL element can be sealed without being exposed to light or heat. Furthermore, even when there is a portion where no light is irradiated because of metal wiring or when a substrate containing an ultraviolet absorber is sealed, the sealing can be reliably performed. The adhesive for sealing an organic EL element of the first aspect of the present invention can be suitably used not only for sealing an organic EL element but also for sealing a polarizing plate of a liquid crystal panel.

The wavelength of the light is not particularly limited as long as the photocationic polymerization initiator is a wavelength capable of initiating polymerization or curing of the photocationic polymerizable compound, and depends on the photosensitive wavelength of the photocationic polymerization initiator. Are appropriately selected. Moreover, it does not specifically limit as the irradiation amount of the said light, It determines suitably by the kind, quantity, etc. of the said photocationic polymerization initiator. The irradiation light source that irradiates light having such a wavelength and irradiation amount is not particularly limited, and examples thereof include a fluorescent lamp, a high-pressure mercury lamp, and a xenon lamp.

In addition, after irradiating light and hardening the organic EL element sealing adhesive of 1st this invention, you may accelerate | stimulate hardening further by heating as needed.

Although it does not specifically limit as a method of sealing an organic EL element using the adhesive agent for organic EL element sealing of 1st this invention, For example, (1) Adhesion for organic EL element sealing of 1st this invention A method of filling and sealing the organic electroluminescence element sealing adhesive between the sealing plate and the thin film structure after the agent is irradiated with light until the organic EL element sealing adhesive is cured; (2) Adhesive for organic electroluminescent element sealing, after irradiating light to the adhesive for organic EL element sealing of 1st this invention until the adhesive for organic electroluminescent element sealing hardens | cures And the like, and a method of sealing and sealing a sealing plate. A method of sealing these organic EL elements is also one aspect of the present invention.

The sealing plate is not particularly limited as long as it can play a role of preventing moisture from entering from the outside. For example, a glass plate, a protective film made of an inorganic material, and the like are preferable. Is not particularly limited as a protective film made of the inorganic material, _{e.g., Si X N Y O Z,} Al 2 O 3, DLC ( diamond-like carbon) and the like.

The organic EL element sealing method of the present invention can be performed at room temperature and normal pressure, but is preferably performed in a space in which moisture is controlled. This is for reliably preventing moisture from entering when the thin film structure is sealed.

When covering the thin film structure with the adhesive for sealing the organic EL element of the first aspect of the present invention, it is preferable to cover the entire thin film structure with the adhesive, but the entire thin film structure is not necessarily covered with the adhesive. It is not necessary to use at least a part of the material constituting the thin film structure that is in contact with the outside air so that the light-emitting characteristics of the organic EL element deteriorate due to being attacked by moisture or oxygen or being oxidized. It may be covered with. Therefore, it is not necessary to cover a part of the anode of the thin film structure (near the outer edge or the side surface).

2 and 3 are cross-sectional views schematically showing a cross section of an organic EL element sealed with the organic EL element sealing adhesive of the first present invention. 2 and 3, the lead-out terminal portions of the anode 2 and the cathode 7 of the thin-film structure 20 are not covered with the double-sided adhesive for sealing the organic EL device, but near the outer edge of the substrate 1. It has been derived until. Moreover, when sealing, after forming with the protective film which consists of an inorganic substance on the outer side of a thin film structure, it is preferable to seal with the adhesive agent for organic EL element sealing of 1st this invention. Is not particularly limited as a protective film made of the inorganic material, _{e.g., Si X N Y O Z,} Al 2 O 3, DLC ( diamond-like carbon) and the like. The method for forming the protective film made of the inorganic material is not particularly limited, and for example, the protective film can be formed by a plasma CVD method, a sputtering method, a vacuum evaporation method, or the like. Further, a protective film may be formed on a film of polyimide, polyparaxylylene, etc., and this film may be laminated on the thin film structure. FIG. 4 schematically shows a cross section of an organic EL element formed with a protective film made of an inorganic material on the outside of the thin film structure and then sealed with the organic EL element sealing adhesive of the first invention. A cross-sectional view is shown.

The organic EL element sealing adhesive of the first aspect of the present invention may be used as it is as described above for sealing, but it can be sealed more efficiently by processing it into a tape shape. It can be performed. 2nd this invention seals an organic electroluminescent element which has a moisture-proof tape and the adhesion layer which consists of the adhesive agent for organic electroluminescent element sealing of 1st this invention formed in the at least single side | surface of the moisture-proof tape. Adhesive tape (hereinafter also referred to as an organic EL element sealing adhesive tape).

In FIG. 5, sectional drawing which shows typically an example of the adhesive tape for organic EL element sealing of 2nd this invention was shown. The organic EL element sealing adhesive tape 30 of the second aspect of the present invention shown in FIG. 5 is composed of a moisture-proof tape 11 and an adhesive layer 12. 5 shows an adhesive tape for sealing an organic EL element before coating on the outer surface of the thin film structure, and a moisture-proof film 11 is formed on one surface of the adhesive layer 12 and is opposite. A release film 13 is formed on the side surface.

The moisture-proof tape has a role of preventing moisture from entering from the outside, and the moisture permeability measured at 50 ° C. and 90% relative humidity is preferably 0.5 g / m ² · 24 h / 100 μm or less. The moisture-proof tape may be a single layer composed of one kind of tape having a low moisture permeability or a laminate composed of two or more kinds of tapes having a small moisture permeability. When the moisture-proof tape is a laminate, it preferably has a layer made of a hygroscopic tape or a tape coated with a water-absorbing agent in addition to a layer made of a tape having a low moisture permeability. In addition, in order to improve moisture resistance, the tape having a low moisture permeability may be a thin film made of aluminum, aluminum oxide, silicon oxide, silicon nitride or the like formed by vapor deposition or the like. Furthermore, as a moisture-proof film, for example, a resin such as polypropylene or polyethylene terephthalate may be laminated on an aluminum foil.

Examples of the tape having low moisture permeability include, for example, polyethylene trifluoride, poly (trifluoroethylene chloride) (PCTFE), polyvinylidene fluoride (PVDF), a copolymer of PVDF and PCTFE, PVDF and polyfluoroethylene chloride. And polyfluorinated ethylene polymers such as copolymers of the above; cycloolefin resins such as polyimide, polycarbonate and dicyclopentadiene; polyesters such as polyethylene terephthalate; polyethylene and polystyrene.

Examples of the hygroscopic film include polyamide polymers such as nylon 6 and nylon 66, copolymers of vinyl alcohol and acrylic acid, polyethylene oxide polymers, copolymers of acrylic acid and starch, and starch. And a film made of a superabsorbent polymer such as a copolymer of acrylonitrile and acrylonitrile.

Examples of the water-absorbing agent include oxides of alkaline earth metals such as silica gel, molecular sieve, calcium oxide, barium oxide, and strontium oxide.

The thickness of the moisture-proof tape is preferably 10 to 1000 μm. More preferably, it is 20-300 micrometers.

The release film is formed for the purpose of protecting the surface of the pressure-sensitive adhesive layer, and is peeled off during sealing. The release film is not particularly limited as long as it has releasability. For example, a release agent made of a silicone-based material on a substrate surface made of paper, polyester such as polyethylene terephthalate (PET), aluminum foil, or the like. And the like coated.

In the adhesive tape for sealing an organic EL element according to the second aspect of the present invention, an adhesive layer made of the adhesive for sealing an organic EL element according to the first aspect of the present invention is formed on the moisture-proof tape. The pressure-sensitive adhesive layer may be formed on the entire surface of the moisture-proof tape so as to cover the entire outer side of the thin film structure to be sealed, or partially formed so as to surround the thin film structure to be sealed. May be. When partially forming the adhesive layer, it is preferable to form so as to surround the entire thin film structure to be sealed, but at least by contacting the outside air among the materials constituting the thin film structure, It may be formed so as to surround a portion where the light emitting characteristics of the organic EL element deteriorate due to being attacked by moisture or oxygen or oxidized.

The pressure-sensitive adhesive layer preferably has a moisture permeability of 30 g / m ² · 24 h / 100 μm or less measured by a moisture-permeable cup method in accordance with JIS Z 0208 under conditions of 60 ° C. and 90% RH. If it exceeds 30 g / m ² · 24 h / 100 μm, the infiltration of oxygen and water cannot be sufficiently prevented, and it consists of an electron injection electrode, an organic thin film and a hole injection electrode provided on the substrate constituting the organic EL element. The thin film structure may be deteriorated.

The adhesive tape for sealing an organic EL element of the second aspect of the present invention preferably has a sheet-like desiccant in the adhesive layer. The said sheet-like desiccant is what prevents the water | moisture content of an adhesion layer and transferring to a thin film structure. Examples of the sheet-like desiccant include porous fluororesin films and olefin resins having pores through which moisture can permeate conventionally known desiccants such as silica gel, molecular sieve, calcium oxide, barium oxide, and strontium oxide. A porous film containing a desiccant; a non-porous moisture-permeable film containing a desiccant, and the like. Thus, when the desiccant is coated with a fluorine resin film or an olefin resin, the desiccant is not in direct contact with the adhesive or the thin film structure, and the organic EL element is not deteriorated. The water absorption effect of the desiccant can be maintained.

The sheet-like desiccant is preferably large enough to cover the thin film structure to be sealed, and is preferably disposed as close to the thin film structure as possible, on the release film side of the adhesive layer. It is preferable to arrange.

In FIG. 6, sectional drawing which shows typically the adhesive tape for organic EL element sealing of 2nd this invention which has a sheet-like desiccant in an adhesion layer was shown. The organic EL element sealing pressure-sensitive adhesive tape 31 of the second aspect of the present invention shown in FIG. 6 includes a moisture-proof tape 11 and a pressure-sensitive adhesive layer 12, and a sheet-like desiccant 14 is disposed on the pressure-sensitive adhesive layer 12. FIG. 6 shows a state before coating on the outer surface of the thin film structure. A moisture-proof tape 11 is formed on one surface of the adhesive layer 12, and a release film is formed on the opposite surface. 13 are stacked.

It does not specifically limit as a method to manufacture the adhesive tape for organic EL element sealing of 2nd this invention, For example, the surface of the said moisture-proof tape is used for the adhesive for organic electroluminescent element sealing of 1st this invention. Examples thereof include a method of coating by a known coating method such as hot melt coating or cast coating.

According to the adhesive tape for sealing an organic EL element of the second aspect of the present invention, since the adhesive for sealing an organic EL element of the present invention 1 is used for the adhesive layer, by irradiating only the adhesive layer of the tape with light, The thin film structure can be sealed. Accordingly, the thin film structure is not directly irradiated with light, and the thin film structure and the gas generated when the adhesive layer is cured can be prevented from touching, so that the device can be easily and easily damaged. The thin film structure can be sealed. In addition, since the pressure-sensitive adhesive layer has low moisture permeability, the organic EL element sealed using the organic EL element sealing pressure-sensitive adhesive tape of the second aspect of the present invention does not deteriorate due to the ingress of oxygen or moisture. Long life can be achieved. The pressure-sensitive adhesive tape for sealing an organic EL element of the second invention can be suitably used for sealing a polarizing plate of a liquid crystal panel in addition to sealing an organic EL element.

Although it does not specifically limit as a method of sealing an organic EL element using the adhesive tape for organic EL element sealing of 2nd this invention, For example, light is irradiated to the adhesive layer of the adhesive tape for organic electroluminescent element sealing Then, before the adhesive layer is cured, a method of pasting and sealing on the thin film structure is suitable. Such a method for sealing an organic EL element is also one aspect of the present invention.

The organic EL element sealing method of the present invention can be performed at room temperature and normal pressure, but is preferably performed in a space in which moisture is controlled. This is for reliably preventing moisture from entering when the thin film structure is sealed.

Further, when the thin film structure is covered with the adhesive tape for sealing an organic EL element of the second aspect of the invention, it is preferable to cover the entire thin film structure with a tape, but the entire thin film structure is not necessarily covered with the tape. It is not necessary to use at least a portion of the material constituting the thin-film structure that is deteriorated in light emission characteristics of the organic EL element due to contact with the outside air, which is affected by moisture or oxygen, or is oxidized. What is necessary is just to coat. Therefore, it is not necessary to cover a part of the anode of the thin film structure (near the outer edge or the side surface).

In FIG. 7, sectional drawing which shows typically the cross section of the organic EL element sealed using the adhesive tape for organic EL element sealing of 2nd this invention was shown. In the organic EL element shown in FIG. 7, the lead-out terminal portions of the anode 2 and the cathode 7 of the thin film structure 20 are not covered with the organic EL element sealing adhesive tape, but are led out to the vicinity of the outer edge of the substrate 1. Yes.
Moreover, sectional drawing which shows typically the cross section of the organic EL element sealed using the adhesive tape for organic EL element sealing of 2nd this invention which has the said sheet-like desiccant in FIG. 8 was shown.

Moreover, when sealing, after forming with the protective film which consists of an inorganic substance on the outer side of a thin film structure, it is preferable to seal with the adhesive tape for organic EL element sealing of 2nd this invention. Is not particularly limited as a protective film made of the inorganic material, _{e.g., Si X N Y O Z,} Al 2 O 3, DLC ( diamond-like carbon) and the like. The method for forming the protective film made of the inorganic material is not particularly limited, and for example, the protective film can be formed by a plasma CVD method, a sputtering method, a vacuum evaporation method, or the like. Further, a protective film may be formed on a film of polyimide, polyparaxylylene, etc., and this film may be laminated on the thin film structure. FIG. 9 schematically shows a cross section of an organic EL element formed with a protective film made of an inorganic substance on the outside of the thin film structure and then sealed with the organic EL element sealing pressure-sensitive adhesive tape of the second invention. A cross-sectional view is shown.

3rd this invention is a double-sided adhesive tape for organic electroluminescent element sealing which has the adhesion layer which consists of the adhesive agent for organic electroluminescent element sealing of 1st this invention, and the separator formed in both surfaces of the adhesion layer. (Hereinafter also referred to as a double-sided adhesive tape for sealing an organic EL element).

In FIG. 10, sectional drawing which shows typically an example of the double-sided adhesive tape for organic EL element sealing of 3rd this invention was shown. In the double-sided adhesive tape 40 for sealing an organic EL element shown in FIG. 10, separators 15 and 16 are formed on both sides of the adhesive layer 12.

The separator functions as a protective film or support for the adhesive layer. The separator is not particularly limited as long as it is made of a film having releasability. For example, a release agent made of a silicone material on the surface of a substrate made of paper, polyester such as polyethylene terephthalate (PET), aluminum foil or the like. And the like coated.

In addition, it is preferable that the separator formed in both surfaces of the said adhesion layer makes a difference in the ease of peeling with respect to an adhesion layer. When irradiating light to the adhesive layer, it is necessary to peel one separator first, and if there is no difference in the ease of peeling of the two separators, it may be impossible to peel only one separator.

The said adhesion layer consists of the adhesive agent for organic electroluminescent element sealing of 1st this invention. The adhesive layer may be formed on the entire surface of the separator so as to cover the entire outer side of the thin film structure to be sealed, or is partially formed to surround the thin film structure to be sealed. May be. When partially forming the adhesive layer, it is preferable to form so as to surround the entire thin film structure to be sealed, but at least by contacting the outside air among the materials constituting the thin film structure, It may be formed so as to surround a portion where the light emitting characteristics of the organic EL element deteriorate due to being attacked by moisture or oxygen or oxidized.

The thickness of the pressure-sensitive adhesive layer is appropriately adjusted in consideration of the configuration of the adhesive for sealing an organic electroluminescence element of the first aspect of the present invention and the setting of the usable time according to the application. It is preferable that it is -1000 micrometers.

The pressure-sensitive adhesive layer preferably has a moisture permeability of 30 g / m ² · 24 h / 100 μm or less by a moisture-permeable cup method based on JIS Z 0208 under the conditions of 60 ° C. and 90% RH. If it exceeds 30 g / m ² · 24 h / 100 μm, the thin film structure comprising the electron injection electrode, the organic thin film, and the hole injection electrode provided on the substrate constituting the organic EL element deteriorates due to the ingress of oxygen or water. May end up.

It does not specifically limit as a method of manufacturing the double-sided adhesive tape for organic electroluminescent element sealing of 3rd this invention, For example, the adhesive for organic electroluminescent element sealing of 1st this invention is set on one separator. Examples thereof include a method of laminating the other separator after coating by a known coating method such as hot melt coating or cast coating.

Since the double-sided pressure-sensitive adhesive tape for sealing an organic EL element of the third invention uses the adhesive for sealing the organic EL element of the first invention for the pressure-sensitive adhesive layer, the thin film is formed by irradiating only the pressure-sensitive adhesive layer with light. The structure can be sealed. Accordingly, the thin film structure is not directly irradiated with light, and the thin film structure and the gas generated when the adhesive layer is cured can be prevented from touching, so that the device can be easily and easily damaged. The thin film structure can be sealed. Moreover, since the said adhesive layer has low moisture permeability, the organic EL element sealed using the double-sided adhesive tape for sealing an organic EL element of the present invention 3 is not deteriorated by the ingress of oxygen or moisture. Long life can be achieved. The double-sided pressure-sensitive adhesive tape for sealing an organic EL element of the third invention can be suitably used for sealing a polarizing plate of a liquid crystal panel in addition to sealing an organic EL element.

Although it does not specifically limit as a method of sealing an organic EL element using the adhesive tape for organic EL element sealing of 3rd this invention, For example, the double-sided adhesive tape for organic electroluminescent element sealing of 3rd this invention One side of the separator is peeled off, and the adhesive layer on the side where the separator is peeled off is irradiated with light, and then the double-sided pressure-sensitive adhesive tape for sealing an organic electroluminescence element is placed around the thin film structure until the adhesive layer is cured. A method of sealing so as to seal, peeling off the other separator of the double-sided pressure-sensitive adhesive tape, and further covering with a sealing plate on the pressure-sensitive adhesive layer is preferable. Such a method of sealing an organic electroluminescence element is also one aspect of the present invention.

The sealing plate is not particularly limited as long as it can play a role of preventing moisture from entering from the outside. For example, a glass plate, a protective film made of an inorganic material, and the like are preferable. Is not particularly limited as a protective film made of the inorganic material, _{e.g., Si X N Y O Z,} Al 2 O 3, DLC ( diamond-like carbon) and the like.

The organic EL element sealing method of the present invention can be performed at room temperature and normal pressure, but is preferably performed in a space in which moisture is controlled. This is for reliably preventing moisture from entering when the thin film structure is sealed.

Moreover, when the thin film structure is covered with the adhesive tape for sealing an organic EL element of the third aspect of the invention, it is preferable to cover the entire thin film structure with a tape, but the entire thin film structure is not necessarily covered with the tape. It is not necessary to use at least a portion of the material constituting the thin-film structure that is deteriorated in light emission characteristics of the organic EL element due to contact with the outside air, which is affected by moisture or oxygen, or is oxidized. What is necessary is just to coat. Therefore, it is not necessary to cover a part of the anode of the thin film structure (near the outer edge or the side surface).

In FIG. 11, sectional drawing which shows typically the cross section of the organic EL element sealed using the adhesive tape for organic EL element sealing of 3rd this invention was shown. In the organic EL element shown in FIG. 11, the lead-out terminal portions of the anode 2 and the cathode 7 of the thin film structure 20 are not covered with the double-sided adhesive tape for sealing the organic EL element, but are led out to the vicinity of the outer edge portion of the substrate 1. ing.

Moreover, when sealing, after forming with the protective film which consists of an inorganic substance on the outer side of a thin film structure, it is preferable to seal with the adhesive tape for organic EL element sealing of 3rd this invention. Is not particularly limited as a protective film made of the inorganic material, _{e.g., Si X N Y O Z,} Al 2 O 3, DLC ( diamond-like carbon) and the like. The method for forming the protective film made of the inorganic material is not particularly limited, and for example, the protective film can be formed by a plasma CVD method, a sputtering method, a vacuum evaporation method, or the like. Further, a protective film may be formed on a film of polyimide, polyparaxylylene, etc., and this film may be laminated on the thin film structure.

Adhesive for sealing an organic electroluminescence element of the first invention, Adhesive tape for sealing an organic electroluminescence element of the second invention, or Double-sided adhesive tape for sealing an organic electroluminescence element of the third invention An organic electroluminescence element sealed with is also one aspect of the present invention.

In addition, the adhesive agent for organic electroluminescent element sealing of this invention can be utilized also as an adhesive agent which fixes a polarizing plate to a liquid crystal panel.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive agent for organic electroluminescent element sealing which can seal an organic electroluminescent element without deteriorating with light or heat, the adhesive tape for organic electroluminescent element sealing, organic electroluminescent element sealing A double-sided adhesive tape for fastening, a method for sealing an organic electroluminescent element, and an organic electroluminescent element can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Examples 1-3, Comparative Examples 1-2)
(1) Production of organic EL element substrate 1 A transparent support substrate was formed by forming an ITO electrode with a thickness of 1000 mm on a glass substrate (25 mm × 25 mm × 0.7 mm). The transparent support substrate was ultrasonically cleaned with acetone, an aqueous alkali solution, ion-exchanged water, and isopropyl alcohol for 15 minutes each, then washed with boiled isopropyl alcohol for 10 minutes, and further UV-ozone cleaner (NL-UV253, Japan). (Laser Electronics Co., Ltd.) Next, this transparent support substrate is fixed to the substrate folder of the vacuum deposition apparatus, and 200 mg of N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (α-NPD) is put in an unglazed crucible. 200 mg of tris (8-hydroxyquinola) aluminum (Alq3) was put in an unglazed crucible having different pressures, and the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. Thereafter, the crucible containing α-NPD was heated and α-NPD was deposited on the substrate at a deposition rate of 15 Å / s to form a 600 正 孔 hole transport layer. Next, the Alq3 crucible was heated to form a light-emitting layer having a thickness of 600 で at a deposition rate of 15 Å / s. Thereafter, the transparent support substrate was transferred to another vacuum deposition apparatus, and 200 mg of lithium fluoride was placed in a tungsten resistance heating boat in the vacuum deposition apparatus, and 1.0 g of aluminum wire was placed in another tungsten boat. Thereafter, the vacuum chamber was depressurized to 2 × 10 ⁻⁴ Pa and 5 μm of lithium fluoride was deposited at a deposition rate of 0.2 Å / s, and then 1000 μm of aluminum was deposited at a rate of 20 Å / s. The inside of the vapor deposition apparatus was returned to normal pressure with nitrogen, and the transparent support substrate was taken out to obtain the organic EL element substrate 1 produced on the transparent support substrate.

(2) Preparation of adhesive According to the composition shown in Table 1, each material was uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper type stirring mixer (Homodisper L type, manufactured by Tokushu Kika Co., Ltd.). A cationic polymerizable adhesive was prepared and used as an organic EL element sealing adhesive.

(3) Device sealing The obtained organic EL device sealing adhesive was applied to a glass back plate with a dispenser, and ultraviolet rays with a wavelength of 365 nm were applied using a high-pressure mercury lamp so that the irradiation amount was 2400 mJ / cm ^2. Irradiated. After that, in a glove box in which nitrogen gas was circulated, an organic EL element substrate and a glass back plate coated with an organic EL element sealing adhesive were bonded together, and allowed to stand for 10 minutes to cure the organic EL. The element was sealed.
In Example 3, the adhesive was cured by heating at 60 ° C. for 5 minutes after bonding.

(4) Evaluation The curability, curing time and cell were evaluated by the following methods.
The results are shown in Table 1.

(Curing property and curing time)
For the sealed organic EL device, every 5 minutes after the end of irradiation, it is tested whether the device substrate and the back plate are shifted by hand, the curability is evaluated according to the following criteria, and the time when the deviation disappears is the curing time. It was.
○: No shift at all.
X: The adhesive slipped softly.

(Cell evaluation)
The sealed organic EL device is exposed to a temperature of 60 ° C. and a humidity of 90% for 100 hours, and then a voltage of 10 V is applied to visually observe the light emitting state of the device (light emission, dark spots, dark lines). The evaluation was made according to the following criteria. The cell of Comparative Example 1 was not evaluated because the adhesive was not cured.
○: Uniform light emission without dark spots △: Light emission but dark spots and dark lines ×: No light emission

(Examples 4 to 9, Comparative Example 3)
(2) Preparation of organic EL element substrate 2 A glass substrate (25 mm × 25 mm × 0.7 mm) was washed by the same method as in Example 1, and then an aluminum electrode was formed to a thickness of 1000 mm, and a transparent support substrate It was. Next, this transparent support substrate is fixed to the substrate folder of the vacuum evaporation apparatus, the first unglazed crucible is 200 mg α-NPD, the second unglazed crucible is 200 mg Alq3, and the tungsten resistance heating boat is lithium fluoride. 200 mg was added, and the inside of the vacuum chamber was decompressed to 1 × 10 ⁻⁴ Pa. Thereafter, 5 nm of lithium fluoride was deposited at a deposition rate of 0.2 Å / s, and then a light emitting layer having a thickness of 600 Å was formed of Alq3 at a deposition rate of 15 Å / s. Next, α-NPD was deposited on the substrate at a deposition rate of 15 Å / s to form a 600 膜厚 hole transport layer. Thereafter, the transparent support substrate was transferred to a sputtering apparatus equipped with a target of indium tin oxide (ITO), the vacuum chamber was depressurized to 2 × 10 ⁻⁴ Pa, and then argon gas was introduced to 0.4 Pa. An ITO film having a thickness of 1000 mm was formed at a rate of 20 mm / s, and a transparent electrode was provided. Further, the transparent support substrate was transferred to a sputtering apparatus equipped with a silicon oxide target, the vacuum chamber was depressurized to 2 × 10 ⁻⁴ Pa, and then argon gas was introduced to 0.4 Pa. A silicon oxide film having a thickness of 1000 Å was formed at a rate of 20 Å / s to provide a protective layer for the element. The inside of the vapor deposition unit was returned to normal pressure with nitrogen, and the transparent support substrate was taken out to obtain a top emission type organic EL element substrate 2 produced on the transparent support substrate.

(2) Preparation of adhesive According to the composition in Table 2 and Table 3, each material was uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper type stirring mixer (Homodisper L type, manufactured by Tokushu Kika Co., Ltd.). A photocationically polymerizable adhesive was prepared and used as an organic EL element sealing adhesive.

(3) Device sealing The obtained organic EL device sealing adhesive was applied on the entire surface of a glass back plate to a thickness of 50 μm using a coating apparatus, and a high-pressure mercury lamp was used to irradiate ultraviolet rays having a wavelength of 365 nm. Was 2400 mJ / cm ² . Thereafter, the glass back plate coated with the organic EL element substrate and the organic EL element sealing adhesive was bonded in a vacuum, and then allowed to stand for 10 minutes to cure the adhesive and seal the organic EL element.

(4) Evaluation The curability, the curing time and the cell were evaluated by the same method as in Example 1, and the electrode durability was evaluated by the following method. The results are shown in Tables 2 and 3.

(Electrode durability evaluation)
An adhesive for sealing an organic EL element was applied on a glass plate on which an aluminum electrode was formed. After irradiation with light, the glass plate on which the ITO electrode was formed was sandwiched from above and cured while being fixed. Thereafter, the sample was allowed to stand at 60 ° C. with a voltage of 10 V applied, and the change of the aluminum electrode surface was visually confirmed.

(Example 10)
(1) Production of organic EL element A transparent support substrate was formed by forming an ITO electrode with a thickness of 100 nm on a glass substrate of 25 mm × 25 mm × 0.7 mm. This was ultrasonically washed with acetone for 15 minutes, ultrasonically washed with an alkaline aqueous solution for 15 minutes, then ultrasonically washed with isopropyl alcohol for 15 minutes, further washed with boiled isopropyl alcohol for 10 minutes, and further UV ozone cleaner ( The immediately preceding treatment was performed with “NL-UV253” manufactured by Nippon Laser Electronics Co., Ltd. Next, the transparent support substrate is fixed to a substrate folder of a commercially available vacuum deposition apparatus (manufactured by Nippon Vacuum Technology Co., Ltd.), and N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine ( 200 mg of α-NPD) was added, and 200 mg of tris (8-hydroxyquinola) aluminum (Alq3) was put in another different unglazed crucible, and the inside of the vacuum chamber was decompressed to 1 × 10 ⁻⁴ Pa. Furthermore, the boat containing α-NPD was heated, and α-NPD was deposited on the substrate at a deposition rate of 15 liters / second to form a 600 liter hole transport layer. The substrate temperature at this time was room temperature. Without removing this from the vacuum chamber, another crucible was heated to form an Alq3 film at a deposition rate of 15 kg / sec. Then, it was once taken out from the vacuum chamber, 200 mg of lithium fluoride was put in a tungsten resistance heating boat, and 1.0 g of aluminum wire was wound around the tungsten filament. Next, the vacuum chamber was depressurized to 2 × 10 ⁻⁴ Pa, and 5 μm of lithium fluoride was deposited at a deposition rate of 0.2 kg / sec, and then 1000 μm of aluminum was deposited at a deposition rate of 20 kg / sec. A light emitting element was manufactured.

(2) Preparation of adhesive The molecular sieve was placed in an eggplant-shaped flask (50 mL), and a propylene carbonate solution of a sulfonium salt-type photocationic initiator having a hydroxyl group under absolutely dry conditions (“SP-170” manufactured by Asahi Denka Co., Ltd.) 10 parts by weight and 5 parts by weight of phthalic anhydride were reacted by stirring for 5 hours while refluxing in 100 parts by weight of toluene to obtain a reaction product. The obtained reaction product was dried under reduced pressure and purified by column chromatography to obtain a high molecular weight photocation initiator.
Next, 1 part by weight of the obtained photocationic initiator, 100 parts by weight of bisphenol A glycidyl ether (“EP828” manufactured by Japan Epoxy Resin Co., Ltd.) and 20 parts by weight of talc are sufficiently stirred with a planetary stirrer, and then depressurized and depressurized. Foaming was performed to obtain a photocationically polymerizable adhesive, which was used as an organic EL element sealing adhesive.

(3) Under the conditions of sealing and drying of the element, an organic EL element sealing adhesive obtained by applying to a glass can with a syringe was applied to the substrate on the light emitting element, and then the organic EL attached to the periphery. The element sealing adhesive was cured by irradiating with an ultraviolet ray having a wavelength of 365 nm using an ultra-high pressure mercury lamp so that the irradiation amount was 2400 mJ / cm ² , thereby sealing the light emitting element.

(4) Evaluation The obtained organic EL device sealing adhesive and the sealed organic EL device were evaluated by the following methods. The results are shown in Table 4.

(Measurement of outgas amount)
After coating the organic EL element sealing adhesive with a thickness of 100 μm using a Baker type applicator, the coating film was irradiated with ultraviolet light having a wavelength of 365 nm using a high-pressure mercury lamp so that the irradiation amount was 2400 mJ / cm ² . . Next, the obtained coating film was measured for a weight reduction rate at 150 ° C. at a temperature rising rate of 10 ° C./min using a thermal analyzer (“TG / DTA 6200” manufactured by Seiko Instrument). Of outgas.

(Generation of dark spots)
After the sealed organic EL device was allowed to stand for 200 hours under the conditions of 40 ° C. and 60% RH, the occurrence of dark spots and dark lines (that is, non-light-emitting portions) when energized (10 V) was confirmed.

(Example 11)
A molecular sieve is placed in an eggplant-shaped flask (50 mL), and under an absolutely dry condition, 10 parts by weight of a sulfonium salt photocationic initiator (“CD-1012” manufactured by Sartomer), a carbodiimide compound (“Carbodilite oil-based resin modified by Nisshinbo Co., Ltd.”) 1 part by weight of the additive V-05 "and 1 part by weight of tolylene diisocyanate were stirred and reacted in 100 parts by weight of toluene under reflux conditions for 5 hours, followed by purification under reduced pressure and column chromatography, A high molecular weight photocationic polymerization initiator was obtained.
Subsequently, 1 part by weight of the obtained cationic photopolymerization initiator, 100 parts by weight of bisphenol A glycidyl ether (“EP828” manufactured by Japan Epoxy Resin Co., Ltd.) and 20 parts by weight of talc were sufficiently stirred with a planetary stirrer, and then the pressure was reduced. Defoaming was performed to obtain a photocationically polymerizable adhesive, which was used as an organic EL element sealing adhesive.
The organic EL element was sealed in the same manner as in Example 1 except that the obtained organic EL element sealing adhesive was used, and the same evaluation was performed. The results are shown in Table 4.

(Comparative Example 4)
An organic EL device in the same manner as in Example 1 except that a sulfonium salt-type photocationic initiator having a hydroxyl group (“SP-170” manufactured by Asahi Denka Co., Ltd.) was used instead of the high molecular weight photocationic polymerization initiator. A sealing adhesive was obtained, and similarly, 365 nm light was irradiated so that the irradiation amount was 2400 mJ, sealing was performed, and the same evaluation was performed. The results are shown in Table 4.

(Example 12)
A transparent support substrate was obtained by forming an ITO electrode with a thickness of 100 nm on a glass substrate having a size of 25 mm × 25 mm × 0.7 mm. The transparent support substrate is subjected to ultrasonic cleaning with acetone for 15 minutes, ultrasonic cleaning with an alkaline aqueous solution for 15 minutes, ultrasonic cleaning with ion exchange water for 15 minutes, ultrasonic cleaning with isopropyl alcohol for 15 minutes, and boiling isopropyl alcohol for 10 minutes. After cleaning in the order of ultrasonic cleaning, a previous treatment was further performed with a UV-ozone cleaner (“NL-UV253” manufactured by Nippon Laser Electronics Co., Ltd.).
Next, the cleaned transparent support substrate is fixed to a substrate folder of a vacuum evaporation apparatus (manufactured by Nippon Vacuum Engineering Co., Ltd.), and N ′, N-di (1-naphthyl) -N, N′− is placed in an unglazed crucible. 200 mg of diphenylbenzidine (α-NPD) was added, and 200 mg of tris (8-hydroxyquinola) aluminum (Alq3) was placed in a different unglazed crucible, and the inside of the vacuum chamber was decompressed to 1 × 10 ⁻⁴ Pa.
Next, the boat containing α-NPD was heated and α-NPD was deposited on the transparent support substrate at a deposition rate of 15 Å / s to form a 600 層 hole transport layer. The temperature of the transparent support substrate at this time was room temperature.
Subsequently, without removing the transparent support substrate on which the hole transport layer was formed from the vacuum chamber, another crucible was heated to deposit Alq3 on the hole transport layer at a deposition rate of 15 Å / s. An organic thin film (light emitting layer) (Alq3 film) was formed.
Next, the transparent support substrate on which the hole transport layer and the light emitting layer are formed is taken out of the vacuum chamber, 200 mg of lithium fluoride is put in a tungsten resistance heating boat, and 1.0 g of aluminum wire is wound around the tungsten filament. It was.
Next, the transparent support substrate on which the hole transport layer and the light emitting layer were formed was set in the vacuum chamber again, and the vacuum chamber was decompressed to 2 × 10 ⁻⁴ Pa.
Then, a tungsten resistance heating boat is heated, lithium fluoride is deposited on the light emitting layer at a deposition rate of 0.2 Å / s, an electron injection layer having a thickness of 5 成膜 is formed, and then the tungsten filament is heated. Then, aluminum was deposited on the electron injection layer at a vapor deposition rate of 20 Å / s, and a cathode having a thickness of 1000 Å was formed to produce a thin film structure.

(2) Preparation of pressure-sensitive adhesive tape for sealing an organic EL element An epoxy resin (bisphenol A glycidyl ether, “Epicoat 828” manufactured by Yuka Shell Epoxy Co., Ltd.) was used as the photocationically polymerizable compound. In addition, an aromatic sulfonium hexafluoroantimony salt (“Adekaoptomer SP170” manufactured by Asahi Denka Kogyo Co., Ltd.) was used as a photocationic polymerization initiator. Further, as the adhesive resin, terephthalic acid 25 mol%, isophthalic acid 25 mol%, ethylene glycol, neopentyl glycol 17.5 mol%, bisphenol A ethylene glycol adduct 17.5 mol%, and tetramethylene ether glycol A polyester copolymerized with 25 mol% was used. Moreover, talc was used as a filler.
80 parts by weight of a cationic photopolymerizable compound, 1 part by weight of a cationic photopolymerization initiator, 20 parts by weight of an adhesive resin, 20 parts by weight of a filler, and 150 parts by weight of methyl ethyl ketone, homodisper type stirring A resin composition was prepared by uniformly stirring and mixing at a stirring speed of 3000 rpm using a mixer (trade name “Homodisper L type”, manufactured by Tokushu Kika Co., Ltd.).
The obtained resin composition was applied to a moisture-proof tape in which polyethylene terephthalate having a thickness of 50 μm was laminated on both surfaces of an aluminum foil having a thickness of 7 μm so that the thickness after coating was 100 μm, and dried. Thus, an adhesive layer was formed to obtain an organic EL element sealing adhesive tape.
In addition, on the adhesion layer of the obtained adhesive tape for organic EL element sealing, the mold release process surface of the PET film in which the silicone mold release process was performed was laminated as a mold release film.

(3) Sealing of the thin film structure After peeling off the release film of the obtained adhesive tape for sealing an organic EL element, the adhesive layer was irradiated with ultraviolet light having a wavelength of 365 nm using an ultra-high pressure mercury lamp, and the irradiation amount was 2400 mJ. Irradiation was performed so as to be / cm ² . Then, quickly coat the tape on the outer surface of the thin film structure transferred into the glove box in which nitrogen gas was circulated, and press the tape by hand to seal the thin film structure to produce an organic EL device. did.

(Example 13)
(1) Preparation of double-sided pressure-sensitive adhesive tape for sealing an organic EL element A resin composition prepared by the same method as in Example 12 was placed on a PET film (release film) having a thickness of 50 μm subjected to a release treatment. Coating was performed using a bar coater so that the thickness after coating was 100 μm and dried to form an adhesive layer. In addition, the adhesion layer was made into the cylinder shape which can enclose the positive hole transport layer, light emitting layer, electron injection layer, and cathode of a thin film structure in the inside.

Next, a double-sided pressure-sensitive adhesive tape for sealing an organic EL element is obtained by laminating a release film-treated surface of a PET film (release film) subjected to silicone release treatment as a protective film on the surface of the pressure-sensitive adhesive layer where the PET film is not formed. Got.

(2) Sealing of the thin film structure After peeling off the PET film as the protective film from the obtained double-sided adhesive tape for sealing the organic EL element, the adhesive layer was irradiated with ultraviolet light having a wavelength of 365 nm using an ultrahigh pressure mercury lamp. Irradiation was performed so that the irradiation amount was 2400 mJ / cm ² . Thereafter, the adhesive layer in a state where the PET film as the support was immediately formed was transferred into a glove box in which nitrogen gas was circulated, on the anode of the thin film structure produced in Example 12, and The hole transport layer, the light emitting layer, the electron injection layer and the cathode are covered so as to surround the outer peripheral portion, and the PET film as the support is peeled off, so that it is on the anode of the thin film structure. Then, an adhesive layer was formed so as to surround the electron injection layer and the outer peripheral portion of the cathode. Then, a glass plate having a size of 25 mm × 25 mm × 0.7 mm was put on the adhesive layer, and then pressure-bonded by hand, and the thin film structure was sealed to manufacture an organic EL element.

(Comparative Example 5)
The thin film structure produced in Example 12 was used as an organic EL element without sealing with a tape. When this organic EL device was left under conditions of a temperature of 60 ° C. and a relative humidity of 90%, no light was emitted after 100 hours.

(Example 14)
(1) Preparation of pressure-sensitive adhesive tape for sealing an organic EL element An epoxy resin (bisphenol A glycidyl ether, Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.) is used as a photocationic polymerizable compound, and an aromatic as a photocationic polymerization initiator. A sulfonium hexafluoride antimony salt (Adekaoptomer SP170, manufactured by Asahi Denka Kogyo Co., Ltd.) was used, a phenoxy resin (EP1256, manufactured by Japan Epoxy Resin Co., Ltd.) as an adhesive resin, and talc as a filler.
30 parts by weight of an epoxy resin, 1 part by weight of a photocation initiator, 70 parts by weight of a phenoxy resin, 20 parts by weight of a filler, and 150 parts of methyl ethyl ketone were mixed with a homodisper type stirring mixer (trade name “Homodisper L type, special equipment company” The resin composition was prepared by uniformly stirring and mixing at a stirring speed of 3000 rpm.
A bar coater was used for the obtained resin composition on a moisture-proof tape composed of a multilayer film having a structure of an easily adhesive polyester film (38 μm) / black printing surface (5 μm) / aluminum foil (7 μm) / polyester film (38 μm). Then, coating and drying were performed so that the thickness after coating was 20 μm to form an adhesive layer, and an adhesive tape for sealing an organic EL element was obtained.
In addition, on the adhesion layer of the obtained adhesive tape for organic EL element sealing, the mold release process surface of the PET film in which the silicone mold release process was performed was laminated as a mold release film.
On the other hand, in order to measure moisture permeability and outgas, the resin composition was applied onto the release-treated PET film so that the thickness after application was 100 μm, dried, and then released. A tape for measurement was prepared by laminating on the PET film adhesive layer surface.

(2) Sealing of thin film structure After peeling off the release film of the obtained adhesive tape for sealing an organic EL element, the adhesive layer was irradiated with ultraviolet light having a wavelength of 365 nm using an ultrahigh pressure mercury lamp, and the irradiation amount was 2400 mJ. Irradiation was performed so as to be / cm ² . Thereafter, the tape was quickly coated on the outer surface of the thin film structure produced in Example 12 which was transferred into a glove box in which nitrogen gas was circulated, and the thin film structure was sealed by tape pressing by hand. Thus, an organic EL device was manufactured.

(Example 15)
A resin composition was prepared in the same manner as in Example 12 except that 25 parts by weight of Epicoat 828 and 10 parts by weight of phenyl glycidyl ether were used instead of 30 parts by weight of the epoxy resin (Epicoat 828). An element sealing adhesive tape and an organic EL element were produced.

(Comparative Example 6)
A resin composition was prepared in the same manner as in Example 15 except that an epoxy compound having a bisphenol skeleton and an ethylene glycol skeleton (Rikaresin BPO-20E manufactured by Shin Nippon Rika Co., Ltd.) was used instead of phenylglycidyl ether. Thus, an organic EL element sealing adhesive tape and an organic EL element were produced.

(Comparative Example 7)
Instead of phenoxy resin, 25 mol% terephthalic acid, 25 mol% isophthalic acid, 17.5 mol% ethylene glycol, neopentyl glycol, 17.5 mol% ethylene glycol adduct of bisphenol A, and 25 mol tetramethylene ether glycol A resin composition was prepared in the same manner as in Example 13 except that polyester obtained by copolymerizing% was used, and an adhesive tape for sealing an organic EL element and an organic EL element were produced using the resin composition.

(Evaluation)
(Energized light emission test)
(1) The organic EL elements obtained in Examples 12 and 13 and Comparative Example 5 were allowed to stand for 500 hours under conditions of a temperature of 60 ° C. and a relative humidity of 90%, and then the organic EL elements were energized (10 V), The presence or absence of dark spots and dark lines (that is, non-light emitting portions) was visually observed. The results are shown in Table 5.
(2) The organic EL elements obtained in Examples 14 and 15 and Comparative Examples 6 and 7 were allowed to stand for 500 hours under conditions of a temperature of 40 ° C. and a relative humidity of 60%, and then the organic EL elements were energized (10 V). The presence or absence of dark spots and dark lines (that is, non-light emitting portions) was visually observed. The results are shown in Table 5.

(Moisture permeability measurement)
One separator of the measuring tapes obtained in Examples 14 and 15 and Comparative Examples 6 and 7 was peeled off, and an ultraviolet ray with a wavelength of 365 nm was applied to the adhesive layer using an ultrahigh pressure mercury lamp, and the irradiation amount was 2400 mJ / cm ^2. Irradiated as follows. Then, the other separator was peeled off, and the moisture permeability of the obtained sample was measured by a moisture permeability cup method according to JIS Z 0208 (40 ° C., 24 hours). The results are shown in Table 5.

(Outgas measurement)
The sample obtained in the moisture permeability measurement was heated with a thermal analyzer (TG / DTA 6200, manufactured by Seiko Instrument Co., Ltd.) at a heating rate of 10 ° C./min, and weight loss during heating was measured. The results are shown in Table 5.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive agent for organic electroluminescent element sealing which can seal an organic electroluminescent element without deteriorating with light or heat, the adhesive tape for organic electroluminescent element sealing, organic electroluminescent element sealing A double-sided adhesive tape for fastening, a method for sealing an organic electroluminescent element, and an organic electroluminescent element can be provided.

It is sectional drawing which shows an example of a thin film structure typically. It is sectional drawing which shows typically the cross section of the organic EL element sealed using the adhesive agent for organic EL element sealing of 1st this invention. It is sectional drawing which shows typically the cross section of the organic EL element sealed using the adhesive agent for organic EL element sealing of 1st this invention. It is sectional drawing which shows typically the cross section of the organic EL element which formed with the protective film which consists of an inorganic substance on the outer side of a thin film structure, and was sealed using the adhesive agent for organic EL element sealing of 1st this invention. . It is sectional drawing which shows typically an example of the adhesive tape for organic EL element sealing of 2nd this invention. It is sectional drawing which shows typically the organic EL element sealing adhesive tape of 2nd this invention which has a sheet-like desiccant in an adhesion layer. It is sectional drawing which shows typically the cross section of the organic EL element sealed using the adhesive tape for organic EL element sealing of 2nd this invention. It is sectional drawing which shows typically the cross section of the organic EL element sealed using the adhesive tape for organic EL element sealing of 2nd this invention which has a sheet-like desiccant. FIG. 9 is a cross-sectional view schematically showing a cross section of an organic EL element formed with a protective film made of an inorganic substance on the outside of a thin film structure and then sealed using the organic EL element sealing pressure-sensitive adhesive tape of the second invention. is there. It is sectional drawing which shows typically an example of the double-sided adhesive tape for organic EL element sealing of 3rd this invention. It is sectional drawing which shows typically the cross section of the organic EL element sealed using the adhesive tape for organic EL element sealing of 3rd this invention.

Explanation of symbols

1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Organic thin film (light emitting layer)
6 Electron injection layer 7 Cathode 8 Sealing plate 9 Adhesive 10 Protective film 11 Moisture-proof tape 12 Adhesive layer 13 Release film 14 Sheet-like desiccants 15 and 16 Separator 20 Thin film structure 30 Adhesive tape 31 for sealing an organic EL element Adhesive tape 40 for sealing an organic EL element having a sheet-like desiccant Double-sided adhesive tape for sealing an organic EL element

Claims (3)

Light that contains an epoxy resin, a photocationic polymerization initiator, an aliphatic hydrocarbon having a hydroxyl group and / or a polyether compound, and initiates a curing reaction by light irradiation, and proceeds through a dark reaction even after blocking light. After irradiating light to the organic electroluminescent device sealing adhesive composed of a cationic polymerizable adhesive and before the organic electroluminescent device sealing adhesive is cured, the sealing plate and the top emission thin film structure A sealing method for a top-emitting organic electroluminescence element, characterized in that the organic electroluminescence element sealing adhesive is filled between bodies and sealed. Light that contains an epoxy resin, a photocationic polymerization initiator, an aliphatic hydrocarbon having a hydroxyl group and / or a polyether compound, and initiates a curing reaction by light irradiation, and proceeds through a dark reaction even after blocking light. An organic electroluminescent element sealing adhesive composed of a cationic polymerizable adhesive is applied to a sealing plate for sealing the organic electroluminescent element, and the organic electroluminescent element sealing adhesive is irradiated with light. blocks light after activation, sealing method of the sealing plate and the top emission type thin film structure and the top emission type organic electroluminescent device, characterized by sealing the organic electroluminescent element laminated to. The method for sealing a top emission organic electroluminescence device according to claim 1 or 2 , wherein the cationic photopolymerization initiator is a salt having a boronic acid represented by the following formula (1) as a counter ion.

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