TW201502193A - Thermosetting composition, surface sealing agent for organic EL element and cured product thereof - Google Patents

Abstract

The purpose of the present invention provides a thermosetting composition which is able to form a cured product layer having less unevenness or cissing, and high surface flatness on a coated object such as an organic EL element. The thermosetting composition includes: (A) a cationic polymerizable compound having 2 or more cationic polymerizable function group within a molecule, (B) a thermal cationic polymerization initiator, (C) a polyether compound (but, a compound having the cationic polymerizable function group is excluded), and (D) leveling agent; wherein a viscosity is 50 mPa.s~ 30000 mPa.s by the E-type viscometer at 25DEG C and 2.5 rpm.

Description

Thermosetting composition, surface sealant for organic EL element, and hardening thereof Object

The present invention relates to a thermosetting composition, a surface sealant for an organic EL device, and a cured product thereof.

An organic electroluminescence (EL) device is expected as a backlight of a liquid crystal or a self-luminous thin flat display device. However, when the organic EL element is in contact with moisture or oxygen, it is extremely likely to deteriorate. Specifically, the interface between the metal electrode and the organic EL layer is peeled off due to the influence of moisture, or the metal is oxidized to increase the resistance, or the organic substance itself is deteriorated by moisture. As a result, the organic EL element may not emit light or the brightness may decrease.

As one of methods for protecting the organic EL element from moisture or oxygen, there is a method of surface sealing the organic EL element with a transparent resin layer. In this method, for example, after applying a curable resin composition to an organic EL element, photocuring or thermal curing is performed, and the organic EL element is surface-sealed. As a curable resin composition used by the above method, for example, a photocationic polymerizable compound, a photocationic polymerization initiator, and a compound having an ether bond (hardening control agent) are proposed. A photocurable resin composition (for example, Patent Document 1); or a resin composition for sealing an organic EL element comprising an epoxy compound, a polyester resin, and a Lewis acid compound (for example, Patent Document 6).

A photocurable resin composition containing an epoxy resin, a photocationic polymerization initiator, and a polyoxymethylene polymer compound (Patent Document 2 and Patent Document 3); or An epoxy resin powder coating containing an epoxy resin, a curing agent, a hardening accelerator, and a polyol (Patent Document 4); or a catalyst containing an epoxy compound, an amine compound, a nitrate, and a polyalkylene ether A thermosetting composition of a diol (for example, Patent Document 5).

Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-231957

Patent Document 2: Japanese Patent Laid-Open Publication No. 2003-192873

Patent Document 3: Japanese Patent Laid-Open Publication No. 2003-246850

Patent Document 4: Japanese Patent Laid-Open Publication No. 2004-67828

Patent Document 5: Japanese Patent Laid-Open No. SHO 58-108221

Patent Document 6: Japanese Patent Laid-Open No. 2014-2875

As described above, the surface sealing of the organic EL element is performed by applying a surface sealant to the organic EL element and then curing the surface sealant. Hardening may be photohardening or heat hardening, but when the component is deteriorated by light, heat hardening is desired. However, this issue Ming and others have found that the following new problems arise: in the coating and heat hardening process of the face sealant, especially in the heat hardening process, the temperature distribution or viscosity of the coating film changes, and it is easy to produce irregularities or cissing, The smoothness of the surface of the cured layer tends to be low.

Surface of the hardened layer of the face sealant that seals the organic EL element When the smoothness is low, for example, the unevenness acts as a lens, and the light extracted from the organic EL element tends to be uneven in the plane. Further, when a barrier film such as an inorganic thin film is formed on the cured layer, defects such as pinholes are likely to occur, and a uniform inorganic barrier film cannot be formed, and it is difficult to obtain sufficient barrier properties.

The present invention has been made in view of the above-described circumstances, and an object of the invention is to provide a thermosetting layer of a cured layer having a small surface roughness and a low surface roughness, such as an organic EL element or the like. Sexual composition.

[1] A thermosetting composition comprising: (A) a cationically polymerizable compound having two or more cationically polymerizable functional groups in one molecule; (B) a thermal cationic polymerization initiator; (C) a polyether a compound (except for the compound having the cationically polymerizable functional group); and (D) a leveling agent; and a viscosity of 50 mPa at 25 ° C and 2.5 rpm as measured by an E-type viscometer. s~30000mPa. s.

[2] The thermosetting composition according to [1], wherein the component (D) is a compound selected from the group consisting of an anthrone-based polymer and an acrylate-based polymer.

[3] The thermosetting composition according to [1] or [2] wherein the component (C) has a weight average molecular weight of from 250 to 10,000.

[4] The thermosetting composition according to any one of [1] to [3] wherein 100 parts by mass of the component (A) contains less than 10 parts by mass of the component (C).

[5] The thermosetting composition according to any one of [1] to [4] wherein the cationically polymerizable functional group is selected from the group consisting of an epoxy group, an oxetanyl group, and a vinyl ether group. More than one of the groups formed.

[6] The thermosetting composition according to any one of [1] to [5] wherein the component (B) is a phosphonium salt.

[7] The thermosetting composition according to any one of [1] to [6] wherein the component (C) is a polyalkylene oxide.

The thermosetting composition according to any one of [1] to [7], wherein the (B) component is contained in an amount of 0.1 part by mass to 5 mass based on 100 parts by mass of the component (A). The component (D) is 0.01 parts by mass to 1 part by mass.

[9] The thermosetting composition according to [8], wherein the component (C) is contained in an amount of less than 10 parts by mass based on 100 parts by mass of the component (A).

[10] A surface sealant for an organic EL device, comprising the thermosetting composition according to any one of [1] to [9].

[11] A cured product which is a cured product of the face sealant according to [10].

According to the present invention, it is possible to provide a thermosetting composition which can form a cured layer having few irregularities, irregularities, and smoothness on the object to be coated, such as an organic EL element.

20‧‧‧Organic EL device

22‧‧‧Display substrate

24‧‧‧Organic EL components

26‧‧‧ Alignment substrate

28A‧‧‧Surface sealant coating

28‧‧‧ Sealing members

30‧‧‧pixel electrode layer

32‧‧‧Organic EL layer

34‧‧‧ opposite electrode layer

FIG. 1 is a schematic view showing an example of an organic EL device.

2(A) to 2(C) are schematic views showing an example of a manufacturing flow of the organic EL device.

Thermosetting composition

The thermosetting composition of the present invention comprises: (A) a cationically polymerizable compound, (B) a thermal cationic polymerization initiator, (C) a polyether compound, and (D) a leveling agent.

(A) cationically polymerizable compound

The cationically polymerizable compound may be a compound having two or more cationically polymerizable functional groups in one molecule. The cationically polymerizable functional group is one or more selected from the group consisting of an epoxy group, an oxetanyl group, and a vinyl ether group. When a plurality of cationically polymerizable functional groups are present, the cationically polymerizable functional groups may be the same or different from each other.

Examples of the epoxy resin having two or more epoxy groups in one molecule include bisphenol A type, bisphenol F type, bisphenol E type, bisphenol S type, bisphenol AD type, and hydrogenated bisphenol A type. Bisphenol type epoxy resin; diphenyl ether type epoxy resin; phenol novolak type, cresol novolak type, biphenol novolak type, bisphenol novolac type, naphthol novolac type, trisphenol novolac Novolac type epoxy resin such as dicyclopentadiene novolac type; biphenyl type epoxy resin; naphthyl type epoxy resin; trisphenol methane type, trisphenol ethane type, trisphenol propane type, etc. An aromatic epoxy resin such as a trisphenol alkene type epoxy resin; an alicyclic epoxy resin; Aliphatic epoxy resin, etc.

Examples of the oxetanyl compound having two or more oxetanyl groups in one molecule include: 1,3-bis[(3-ethyl-3-oxetanyl)methoxy]benzene, An aromatic oxetane compound such as 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene; 1,4-double {[(3-ethyl) 3-oxo-oxobutyl)methoxy]methyl}cyclohexane, 4,4'-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl} An alicyclic oxetane compound such as bicyclohexane; bis[1-ethyl(3-oxetanyl)]methyl ether, bis(3-ethyl-3-oxetanylmethyl)ether, An aliphatic oxetane compound such as trimethylolpropane tris(3-ethyl-3-oxetanylmethyl)ether or pentaerythritol tris(3-ethyl-3-oxetanylmethyl)ether.

Examples of the vinyl ether compound having two or more vinyl ether groups in one molecule include an alicyclic vinyl ether compound such as cyclohexane dimethanol divinyl ether; ethylene glycol divinyl ether, diethylene glycol An aliphatic vinyl ether compound such as alcohol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether or dipropylene glycol divinyl ether.

Among these, in order to easily adjust the viscosity of the thermosetting composition, a cationically polymerizable compound which is liquid at 25 ° C is preferable. The cationically polymerizable compound which is liquid at 25 ° C is preferably an epoxy resin having two or more epoxy groups in one molecule, from the viewpoint of easily obtaining adhesion to a material to be coated. The epoxy resin is preferably an aromatic epoxy resin in terms of easily improving the moisture resistance of the cured product and the like.

The aromatic epoxy resin is preferably a bisphenol epoxy compound or a cresol novolac A lacquer type epoxy compound or the like is more preferably a bisphenol type epoxy compound. The bisphenol type epoxy compound is preferably a compound represented by the formula (X), and a preferred example includes a compound represented by the formula (X').

In the general formula (X) and the general formula (X'), X represents a single bond, a methylene group, an isopropylidene group, -S- or -SO ₂ -; and R ₁ independently represents a carbon number of 1 to 5; An alkyl group; n represents an integer of 2 or more; and P represents an integer of 0-4. n is preferably 2 to 4.

The cationically polymerizable compound preferably has a low molecular weight because it is easy to adjust the viscosity of the thermosetting composition to a range described later, and it is easy to ensure fluidity during coating or curing. Specifically, the weight average molecular weight of the cationically polymerizable compound is preferably from 200 to 800, more preferably from 300 to 700. The "weight average molecular weight (Mw)" was measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

The cationically polymerizable functional group equivalent of the cationically polymerizable compound is preferably from 100 g/eq to 800 g/eq.

The viscosity of the cationically polymerizable compound measured by an E-type viscometer at 25 ° C and 2.5 rpm is preferably 50 mPa. s~30000mPa. s. The reason is The epoxy resin having a viscosity within the above range is likely to adjust the viscosity of the thermosetting composition to a range described later.

The content of the cationically polymerizable compound may be relative to the thermosetting composition It is 60% by mass or more, and preferably 70% by mass or more. The (A) cationically polymerizable compound contained in the thermosetting composition may be one type, and two or more types having different types or molecular weights may be combined.

(B) Thermal cationic polymerization initiator

The thermal cationic polymerization initiator is a compound which can produce a cationic species which initiates polymerization by heating. The thermal cationic polymerization initiator is not particularly limited and may be appropriately selected depending on the curing conditions or the kind of the cationically polymerizable compound. For example, when the cationically polymerizable compound is an epoxy resin, the thermal cationic polymerization initiator may be a phosphonium salt such as a quaternary ammonium salt or a phosphonium salt.

Among them, a quaternary ammonium salt is preferred from the viewpoint of improving the storage stability of the thermosetting composition or suppressing the coloration of the cured product. Examples of the quaternary ammonium salt include a salt (B1) containing a specific quaternary ammonium ion and a counter anion.

The quaternary ammonium ion constituting the salt (B1) can be represented by the following formula (1).

R ₁ , R ₂ and R _{3 in the} formula (1) each independently represent an alkyl group having 1 to 10 carbon atoms which may have a substituent, an aryl group having 6 to 10 carbon atoms which may have a substituent, or An aralkyl group having 7 to 20 carbon atoms which may have a substituent. In particular, R ₁ , R ₂ and R ₃ are each independently a methyl group, a phenyl group or a benzyl group.

The substituent which R ₁ , R ₂ and R ₃ may have is not particularly limited, but is preferably selected from an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, -F, - A functional group in a group consisting of Cl, -Br, -I, -NO ₂ , -CN, and a group represented by the following formula (2).

R ₁₃ , R ₁₄ and R _{15 in the} formula (2) each independently represent a hydrogen group or a hydrocarbon group having 1 to 10 carbon atoms. Among them, in view of improving the storage stability of the thermosetting composition, etc., it is preferred that all of R ₁₃ , R ₁₄ and R ₁₅ are a hydrocarbon group. The hydrocarbon group may be a linear, branched or cyclic aliphatic group or may be aromatic.

Ar of the formula (1) represents an aryl group having 6 to 10 carbon atoms which may have a substituent. Ar is preferably an aromatic hydrocarbon group, and may be, for example, a phenyl group or a naphthyl group. The substituent which the Ar of the formula (1) may have is not particularly limited, and may be the same as the substituent which R ₁ , R ₂ and R _{3 of the} formula (1) may have.

The bonding position or the number of substituents of the substituent bonded to Ar is not particularly limited. For example, when the substituent bonded to Ar is an electron withdrawing group such as -F, -Cl, -Br, -I, -NO ₂ or -CN, it is preferably Ar with respect to the general formula (1) At the bonding position to the methylene group, the substituent is bonded to the meta or para position. When the electron-bonding group is bonded to this position, the hardening reaction of the cationically polymerizable compound is easily promoted. Further, the number of electron withdrawing groups bonded to Ar is preferably 2 or less.

On the other hand, when the substituent bonded to Ar is an electron donating group, for example, When the alkyl group, the alkoxy group or the group represented by the formula (2) is preferred, the bonding position of Ar to the methylene group of the formula (1) is preferred, and the substituent is bonded to the para position. When the electron donating group is bonded to this position, the hardening reaction of the cationically polymerizable compound is easily promoted. When the substituent bonded to Ar is an electron-donating group, the hardening reaction of the cationically polymerizable compound is more likely to be promoted than when the substituent bonded to Ar is an electron-withdrawing group.

Preferred examples of the quaternary ammonium ion represented by the general formula (1) include the following ion.

Examples of the counter anion constituting the salt (B1) include: [CF ₃ SO ₃ ] ^- , [C ₄ F ₉ SO ₃ ] ^- , [PF ₆ ] ^- , [AsF ₆ ] ^- , [Ph ₄ B] ^- , Cl ^- , Br ^- , I ^- , [OC(O)R ₁₆ ] ^- (R ₁₆ represents an alkyl group having 1 to 10 carbon atoms), [SbF ₆ ] ^- , [B(C ₆ F ₅ ) ₄ ] ^- , [B(C ₆ H ₄ CF ₃ )4] ^- , [(C ₆ F ₅ ) ₂ BF ₂ ] ^- , [C ₆ F ₅ BF ₃ ] ^- , or [B(C ₆ H ₃ F ₂ ) ₄ ] ^- . Among them, an anion having a small logarithm (pKa) of the reciprocal of the acid dissociation constant is preferred. The smaller the pKa, the easier the salt (B1) to ionize, and the more the hardening reaction of the epoxy resin is promoted.

Preferred examples of the salt (B1) include the following compounds.

If the salt (B1) is heated to a temperature above the fixed temperature, then the salt (B1) is four. Protons of the benzylic position of the ammonium ion are detached, while protons are supplied to the epoxy group of the epoxy resin. The epoxy group of the proton-donating epoxy resin is opened and cured by polymerization with a plurality of other epoxy resins. Thus, by heating the salt (B1) to above The temperature allows the polymerization of the epoxy resin to begin. On the other hand, such a reaction is hard to occur at a low temperature, so that the storage stability of the thermosetting composition can be improved.

The reactivity of the quaternary ammonium ion can be obtained by the aryl group adjacent to the methylene group. Daiji to adjust. For example, by setting the substituent of the aryl group as an electron-donating group, the reactivity of the quaternary ammonium ion can be improved.

100 parts by mass of the cationically polymerizable compound (component (A)), The content of the thermal cationic polymerization initiator is preferably from 0.1 part by mass to 5 parts by mass, more preferably from 0.1 part by mass to 3 parts by mass. When the content of the thermal cationic polymerization initiator is more than or equal to fixed, the cationically polymerizable compound is easily sufficiently cured. On the other hand, when the content of the thermal cationic polymerization initiator is fixed or less, not only the stability of the resin composition during storage is not easily impaired, but also the residual of the unreacted thermal cationic polymerization initiator in the cured product can be reduced. The amount is not easy to impair the heat resistance of the cured product. The thermal cationic polymerization initiator may contain only one compound or a combination of two or more compounds.

The amount of ammonium ion in the thermal cationic polymerization initiator and the thermosetting composition The ratio of the amount of the cationically polymerizable functional group contained in the material (equivalent ratio (the number of ammonium ions in the thermal cationic polymerization initiator / the number of cationically polymerizable functional groups in the thermosetting composition) × 100) Preferably, it is 0.5% to 10%, more preferably 0.5% to 1%.

The present inventors have found that in order to suppress the application of the thermosetting composition and The heat-hardening process, particularly the unevenness or collapse in the heat-hardening process, is effective in combining the (C) polyether compound and the (D) leveling agent.

Although the reason is not necessarily clear, it is considered as follows. That is, it can be considered The reason is that during the heat hardening of the thermosetting composition, the (E) ether bond portion of the polyether compound can prevent (D) the surface tension adjusting function of the leveling agent, and capture (B) the thermal cationic polymerization initiator. The cations delay the polymerization of the (A) cationically polymerizable compound. Thereby, the time during which the thermosetting composition during the heat curing can flow can be prolonged, and during this period, the (D) leveling agent can sufficiently function.

(C) polyether compound

The polyether compound is a compound containing a repeating unit having an ether bond and containing no such cationically polymerizable functional group. Such a polyether compound may be a polyalkylene oxide or a crown ether or the like.

The alkylene chain of the alkylene oxide as a constituent unit of the polyalkylene oxide has 2 to 4 carbon atoms, preferably 2 to 3 carbon atoms. Examples of the polyalkylene oxide include polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, etc., preferably polyethylene glycol. The molecular end of the polyalkylene oxide may be a hydroxyl group, and may also be etherified or esterified by other compounds.

Examples of crown ethers include: 12-crown-4, 15-crown-5, 18-crown-6, and the like.

Among them, polyethylene glycol and crown ether are particularly preferred. The reason for this is that these are easily mixed with the (A) cationically polymerizable compound.

The weight average molecular weight of the polyether compound is preferably from 150 to 10,000, more preferably from 250 to 10,000, and still more preferably from 400 to 10,000. When the molecular weight of the polyether compound is more than or equal to a fixed value, the ether bond portion is sufficiently contained in the polyether compound, so that the cation of the thermal cationic polymerization initiator is easily captured sufficiently, and the polymerization of the (A) cationically polymerizable compound is easily obtained. The delay effect. As a result, it is easy to prolong the time during which the thermosetting composition in the heat-hardening process can flow, and it is easy to obtain sufficient Leveling effect. On the other hand, when the molecular weight of the polyether compound is fixed or less, it is difficult to cause a decrease in solubility in the thermosetting composition or an increase in viscosity.

100 parts by mass of the cationically polymerizable compound (component (A)), The content of the polyether compound is preferably less than 10 parts by mass, more preferably 0.05 parts by mass or more and 8 parts by mass or less, still more preferably 0.5 parts by mass or more and 5 parts by mass or less. When the content of the polyether compound is at least the above, it is easy to sufficiently capture the cation of the thermal cationic polymerization initiator by the ether bond portion, and it is easy to obtain a retardation effect of the polymerization reaction of the cationically polymerizable compound. As a result, it is easy to sufficiently level the thermosetting composition. On the other hand, when the content of the polyether compound is at most fixed, it is likely to be sufficiently dissolved in the thermosetting composition, and it is difficult to solidify when the composition is stored at normal temperature, and the storage stability of the composition is not easily impaired.

As described above, in order to capture thermal cationic polymerization during heat hardening A polyether compound may be added to the cation or the like of the initiator. Therefore, the content of the polyether compound is preferably set in accordance with the content (molar amount) of the thermal cationic polymerization initiator. Specifically, a sufficient polymerization delay effect is easily obtained by not increasing the content ratio of the thermal cation-initiating initiator (relative to the polyether compound). On the other hand, by making the content ratio of the polyether compound (relative to the thermal cationic polymerization initiator) not excessively increased, the curing failure can be suppressed.

(D) Leveling agent

In the process of heat-hardening the thermosetting composition, the leveling agent is aligned on the surface of the coating film of the thermosetting composition to uniformize the surface tension of the coating film, and it is difficult to cause collapse or the like, and is easily coated. Wetting spread on the cloth. Therefore, the leveling agent is more Good choices are made to satisfy the following formula.

S=γv-γA-γI>0

(S: expansion coefficient, γv: surface tension of the coating film of the thermosetting composition, γA: surface tension of the leveling agent, γI: interfacial tension between the thermosetting composition and the leveling agent)

The leveling agent can have a surface tension (γA) smaller than a surface tension (γv) of the coating film of the thermosetting composition in the heat curing step, and an interfacial tension (γI) of the thermosetting composition and the leveling agent also becomes A small way to make a choice. In order to obtain a sufficient leveling effect even if the amount added is small, the leveling agent is preferably incompatible with the cationically polymerizable compound.

The leveling agent can improve the wettability of the composition to the coated object by adjusting the surface tension of the coating film surface, and improve the fluidity or defoaming property of the coating film surface to smooth the surface, and the smoothing agent The effect is manifested by a slight addition amount. Therefore, for example, an oxime-based polymer or an acrylate-based polymer having a surface modification effect smaller than a fluorine-based polymer is preferable.

The anthrone-based polymer is preferably a polymer containing a structure derived from polydimethyloxane represented by the following formula. n in the following formula is preferably 2 or more, more preferably 2 to 140.

Examples of the fluorenone polymer include: polydimethyl siloxane, polyether modification Polydimethyloxane, polymethylalkyloxane.

The acrylate-based polymer is preferably a polymer of an alkyl acrylate. The alkyl chain of the alkyl acrylate preferably has 4 or more carbon atoms, more preferably 6 or more. The upper limit of the carbon number of the alkyl chain of the alkyl acrylate may be, for example, 12. Examples of the alkyl acrylate include butyl acrylate, 2-ethylhexyl acrylate, and the like. The acrylate-based polymer preferably has no fluorine atom. The alkyl acrylate may be one type or two or more types.

Examples of the acrylate-based polymer include a copolymer of butyl acrylate and 2-ethylhexyl acrylate.

The molecular weight of the anthrone-based polymer or the acrylate-based polymer can be set to about 1,000 to 10,000. When the molecular weight is fixed or more, the leveling agent can be prevented from oozing out of the cured product. On the other hand, when the molecular weight is fixed or less, the leveling agent is likely to be aligned on the surface of the coating film of the thermosetting composition, and a sufficient leveling effect is easily obtained.

The content of the leveling agent is preferably from 0.01 part by mass to 1 part by mass, more preferably from 0.05 part by mass to 0.5 part by mass, per 100 parts by mass of the cationically polymerizable compound (component (A)). When the content of the leveling agent is fixed or more, a sufficient amount of the leveling agent tends to be aligned on the surface of the coating film of the curable resin composition, and a sufficient leveling effect is easily obtained. On the other hand, when the content of the leveling agent is fixed or less, the compatibility between the leveling agent and the cationically polymerizable compound or the transparency of the cured product is not easily impaired.

The content ratio (D)/(C) (mass ratio) of the leveling agent (D) to the polyether compound (C) is preferably from 0.002 to 20, more preferably from 0.01 to 10, still more preferably from 0.03 to 5.

(E) Other optional ingredients

The thermosetting composition of the present invention may contain (E) other optional components within the range which does not impair the effects of the present invention. Examples of other optional components include other resin components other than the above (A), a coupling agent, a filler, a modifier, an antioxidant, a stabilizer, a solvent, and the like.

Examples of other resin components include solid cationic polymerization compounds (eg solid epoxy resin, etc.), polyamine, polyamidimide, polyurethane, polybutadiene, polychloroprene, polyether, polyester, styrene - A butadiene-styrene block copolymer, a petroleum resin, a xylene resin, a ketone resin, a cellulose resin, a fluorine-based oligomer, a fluorene-based oligomer, a polysulfide-based oligomer, or the like. The other resin component contained in the thermosetting composition may be one type or two or more types.

Examples of coupling agents include: decane coupling agents, titanium coupling agents, and zirconium couplings. Mixture, aluminum coupler, etc. The coupling agent can improve the adhesion to the substrate of the organic EL device or the like.

Examples of the decane coupling agent include: 1) a decane coupling agent having an epoxy group, 2) a decane coupling agent having a functional group reactive with an epoxy group, and 3) another decane coupling agent. The decane coupling agent is preferably a decane coupling agent that reacts with the epoxy resin in the thermosetting composition, from the viewpoint of not allowing the low molecular weight component to remain in the cured film. The decane coupling agent which reacts with the epoxy resin is preferably a 1) decane coupling agent having an epoxy group, or 2) a decane coupling agent having a functional group reactive with an epoxy group. The reaction with an epoxy group means an addition reaction with an epoxy group.

1) Examples of the decane coupling agent having an epoxy group include: γ-glycidyloxygen Propyltrimethoxydecane, β-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, and the like. 2) A functional group reactive with an epoxy group includes, in addition to an amine group such as a primary amino group or a secondary amino group, a carboxyl group or the like, a group which converts into a functional group reactive with an epoxy group (for example, a methyl group) Acryl sulfhydryl, isocyanate group, etc.). Examples of the decane coupling agent having such a functional group reactive with an epoxy group include: N-2-(aminoethyl)-3-aminopropylmethyldimethoxydecane, N-2- (Aminoethyl)-3-aminopropylmethyltrimethoxydecane, and the like. 3) Examples of other decane coupling agents include vinyltriethoxydecane, vinyltrimethoxydecane, and the like. The thermosetting composition may contain only one type of the decane coupling agent, or may contain two or more types.

The molecular weight of the decane coupling agent is preferably from 80 to 800. If a decane coupling agent When the molecular weight exceeds 800, the adhesion may be lowered.

The content of the decane coupling agent relative to 100 parts by mass of the thermosetting composition It is preferably 0.05 parts by mass to 30 parts by mass, more preferably 0.1 parts by mass to 20 parts by mass, still more preferably 0.3 parts by mass to 10 parts by mass.

Examples of the filler include: glass beads, styrene polymer particles, a The acrylate-based polymer particles, the ethylene-based polymer particles, the propylene-based polymer particles, and the like. Examples of the modifier include a polymerization initiator, an age resistor, a surfactant, a plasticizer, and the like. Examples of the stabilizer include ultraviolet absorbers, preservatives, antibacterial agents, and the like.

The term "antioxidant" means that it is produced by plasma irradiation or sunlight irradiation. Free radical inactivating agent (Hindered Amine Light Stabilizer, HALS)), or the decomposition of peroxides, etc. The cured product of the thermosetting composition containing an antioxidant can suppress discoloration. Examples of antioxidants include: Tinuvin123 (bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate), Tinuvin 765 (double (1,2,2,6) , a mixture of 6-pentamethyl-4-piperidinyl) sebacic acid and methyl 1,2,2,6,6-pentamethyl-4-piperidinyl sebacic acid) and the like.

The solvent allows the components to be uniformly dispersed or dissolved. The solvent is an organic solvent, Examples of the solvent include a ketone solvent such as acetone, methyl ethyl ketone or methyl isobutyl ketone; an ether such as ethylene glycol monoalkyl ether, ethylene glycol dialkyl ether, propylene glycol or dialkyl ether; An aprotic polar solvent such as N-methylpyrrolidone; an ester such as ethyl acetate or butyl acetate.

Physical properties of thermosetting compositions

The viscosity of the thermosetting composition of the present invention measured by an E-type viscometer at 25 ° C and 2.5 rpm is preferably 50 mPa. s~30000mPa. s, more preferably 100mPa. s~10000mPa. s. When the viscosity of the thermosetting composition is within the above range, coatability (for example, screen printing property) becomes high. The viscosity of the thermosetting composition was measured by an E-type viscometer (RC-500 manufactured by Toki Sangyo Co., Ltd.).

The moisture content of the thermosetting composition of the present invention is preferably 0.1% by mass. More preferably, it is 0.06 mass% or less. The organic EL element is easily deteriorated by moisture. Therefore, it is preferred to reduce the moisture content of the thermosetting composition as much as possible. The water content of the thermosetting composition can be determined by weighing a sample of about 0.1 g of the sample, heating it to 150 ° C using a Karl-fischer moisture meter, and measuring the moisture generated at this time. Amount (solid gasification method).

The reactivity of the thermosetting composition of the present invention shows the temperature by The heat-resistant temperature of the sealing member is suitably adjusted, preferably from 70 ° C to 150 ° C, more preferably from 80 ° C to 110 ° C, and even more preferably from 90 ° C to 100 ° C. The reactivity display temperature is closely related to the hardenable temperature of the thermosetting composition. When the reaction display temperature is 150° C. or lower, the thermosetting composition can be heat-cured at 150° C. or lower, and there is little possibility of affecting the organic EL element at the time of surface sealing. On the other hand, when the reaction activity temperature is 70° C. or more, it is difficult to produce an unnecessary curing reaction of the cationically polymerizable compound (component (A)) during storage of the composition, and the storage stability is improved.

Reactive activity display temperature can be determined by differential scanning calorimetry (differential The value of the rise in the peak of heat generation measured by Differential Scanning Calorimetry (DSC) was measured. The reaction temperature can be adjusted by the type of the (A) cationically polymerizable compound or (B) the thermal cationic polymerization initiator, preferably the structure of the quaternary ammonium ion contained in the (B) thermal cationic polymerization initiator. .

The cured product of the thermosetting composition of the present invention is preferably transparent to visible light. Highly. The parallel light transmittance of the 380 nm wavelength region (visible. ultraviolet light) of the cured film obtained by curing the thermosetting composition having a film thickness of 10 μm at 100 ° C for 30 minutes is preferably 80% or more, more preferably 90% or more. More preferably, it is 95% or more. When the parallel light transmittance is 80% or more, the light emitted from the organic EL element through the cured product of the thermosetting composition can be efficiently extracted. However, when the thermosetting composition of the present invention is used for a back emission type organic EL element, the transparency of the cured product is not particularly limited. The parallel light transmittance of the hardened material can be borrowed It was measured by a fully automatic haze meter TC-H III DPK manufactured by Tokyo Electron Co., Ltd.

The thermosetting composition of the present invention can be produced, for example, by the following steps. Manufactured by mixing the components at a temperature lower than the reaction display temperature (for example, 60 ° C or lower) in an inert gas atmosphere. The mixing of each component can be carried out by a method in which each component is placed in a flask and stirred, or a method of kneading by a three-roll mill.

The thermosetting composition of the present invention can be preferably used as a face of an optical semiconductor Sealants. The optical semiconductor is, for example, an element that converts electricity into light and emits light. Examples of the optical semiconductor include an inorganic light emitting diode (LED) element, an organic EL element, and the like, and an organic EL element is preferable. That is, the thermosetting composition of the present invention can be preferably used as a face sealant for an organic EL element.

2. Organic EL device

FIG. 1 is a schematic view showing an example of an organic EL device that can constitute an organic EL panel. As shown in FIG. 1, the organic EL device 20 includes a display substrate 22 on which an organic EL element 24 is disposed, an opposite substrate 26, and a sealing member 28 disposed at least between the organic EL element 24 and the opposite substrate 26, and The organic EL element 24 is sealed. The sealing member 28 covers the periphery of the organic EL element 24 (surface sealing) and contains a cured product of the surface sealant (thermosetting composition) of the present invention.

The display substrate 22 and the counter substrate 26 are usually a glass substrate or a resin film, and a glass substrate or a transparent resin film which is transparent to at least one of the display substrate 22 and the counter substrate 26 . Examples of such a transparent resin film include polyethylene terephthalate An aromatic polyester resin such as a diester.

When the organic EL element 24 is of a top emission type, The organic EL element 24 includes a pixel electrode layer 30 (including aluminum or silver, etc.), an organic EL layer 32, and a counter electrode layer 34 (including indium tin oxide (Indium Tin Oxide) or indium zinc oxide from the display substrate 22 side. (Indium Zinc Oxide, IZO), etc.). The pixel electrode layer 30, the organic EL layer 32, and the counter electrode layer 34 can be formed by vacuum evaporation or sputtering.

The organic EL device can be manufactured, for example, by the following steps: 1) Preparation The step of placing the organic EL element on the substrate, 2) the step of covering the organic EL element with a surface sealant, and 3) the step of heat-hardening the facing sealant. The step of covering the organic EL element with the surface sealant can be carried out by applying a liquid surface sealant or by thermocompression bonding a solid (sheet-like) face sealant, and preferably, a coating liquid is used. Face sealant to carry out.

2(A) to 2(C) show an example of a manufacturing flow of the organic EL device. Schematic diagram. The organic EL device 20, 1) is a step of preparing the display substrate 22 in which the organic EL element 24 is laminated (Fig. 2(A)); 2) applying the surface sealant of the present invention to the organic EL element 24 to form a face sealant. a step of applying the coating film 28A (Fig. 2(B)); and 3) disposing the counter substrate 26 on the coating film 28A of the surface sealant, and heating and curing the coating film 28A of the facing sealant to form the sealing member 28, and The counter substrate 26 is bonded together (Fig. 2(C)). In this way, the organic EL device 20 can be obtained.

The application of the face sealant can be carried out by a method such as screen printing, dispenser coating, slit coating, spray coating or the like.

The heat hardening of the face sealant can be carried out at a relatively low temperature. Heat hard The temperature is preferably a temperature at which (B) the thermal cationic polymerization initiator in the surface sealant is activated, preferably 70 ° C to 150 ° C, more preferably 80 ° C to 110 ° C, and even more preferably 90 ° C to 100 ° °C. When the heat curing temperature is 70° C. or higher, the (B) thermal cationic polymerization initiator is easily activated sufficiently, and the (A) cationically polymerizable compound is easily sufficiently cured. When the heat curing temperature is 150 ° C or lower, the possibility of affecting the organic EL element at the time of heat curing can be reduced.

Heat hardening can be known by, for example, heating using an oven or a heating plate. The way to proceed. The heating time is preferably from 10 minutes to 120 minutes, more preferably from 20 minutes to 90 minutes, and even more preferably from 30 minutes to 60 minutes.

The thickness of the sealing member 28 may be sufficient to cover the thickness of the organic EL element 24, and may be, for example, about 0.1 μm to 20 μm.

On the sealing member 28, a passivation film can be further formed as needed. The passivation film may cover the entire face of the sealing member 28, or may cover only a portion. The passivation film can be, for example, an inorganic compound film formed by a plasma chemical vapor deposition (CVD) method. The material of the passivation film is preferably a transparent inorganic compound, and examples thereof include cerium nitride, cerium oxide, SiONF, and SiON, and are not particularly limited. The thickness of the passivation film is preferably from 0.1 μm to 5 μm.

Since the surface sealant of the present invention contains (C) a polyether compound, in the heat hardening process of the face sealant, the effect of the leveling agent can be prevented (D), and the time during which the face sealant can flow can be extended. Thereby, in the heat hardening process of the surface sealant, the time during which the (D) leveling agent acts can be prolonged. Therefore, it is presumed that on the organic EL element, A cured layer having irregularities or less collapse and high surface smoothness can be formed.

Example

Hereinafter, the present invention will be described in more detail with reference to examples. The scope of the invention is not to be construed as limited by the embodiments.

1. Material of thermosetting composition (A) cationically polymerizable compound

Bisphenol F type epoxy resin (weight average molecular weight is 338, epoxy equivalent is 165g/eq~175g/eq, E-type viscosity (@25°C, 2.5rpm) is 3000mPa.s~4000mPa.s, within 1 molecule Number of cationically polymerizable functional groups: 2): YL983U, manufactured by Japan Epoxy Resins

(B) Thermal cationic polymerization initiator

A quaternary ammonium salt represented by the following formula: CXC-1612, manufactured by King Industries

(C) polyether compound (polyethylene glycol)

PEG#400: Weight average molecular weight is 445

PEG#1000: weight average molecular weight is 1030

PEG#2000: Weight average molecular weight is 2180

PEG#4000: Weight average molecular weight is 3220

PEG#6000: Weight average molecular weight is 8450

(crown ether)

18-crown-6-ether: molecular weight 264

(D) Leveling agent

Anthrone-based polymer: LS-460, manufactured by Nanben Chemical Company

(E) coupling agent

3-glycidoxypropyltrimethoxydecane (molecular weight: 236): KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.

2. Preparation of thermosetting composition (Example 1)

In a flask substituted with nitrogen, 100 parts by mass of epoxy resin (YL983U), 2 parts by mass of quaternary ammonium salt (CXC-1612), and 2 parts by mass of polyether compound (PEG #400) at 50 ° C 0.3 parts by mass of a leveling agent (LS-460) and 1 part by mass of a decane coupling agent (KBM-403) were stirred and mixed to obtain a thermosetting composition.

(Example 2 to Example 9, Comparative Example 1 to Comparative Example 2)

A thermosetting composition was obtained in the same manner as in Example 1 except that the composition of the thermosetting composition was changed as shown in Table 1.

The viscosity, storage stability, and smoothness of the surface of the cured product of the obtained thermosetting composition were evaluated by the following methods.

(viscosity)

The viscosity of the obtained thermosetting composition was measured at 25 ° C and 2.5 rpm using an E-type viscometer (RC-500 manufactured by Toki Sangyo Co., Ltd.).

(save stability)

A predetermined amount of the obtained thermosetting composition was extracted and stored at 23 ° C for 24 hours, and then the presence or absence of white turbidity and fluidity of the thermosetting composition was observed. When the thermosetting composition after storage was not turbid, and the fluidity was not lowered, it was set to "None", and the heat-hardened composition after storage was white turbid, and the fluidity was remarkably lowered.

(Smoothness of the surface of the hardened layer)

The thermosetting composition obtained by printing on a glass substrate (7 cm × 7 cm × 0.7 mm thick) which was previously cleaned by ozone treatment using a screen printing machine (Screen Printer model 2200, manufactured by Mitsui (MITANI)) . The application of the thermosetting composition was carried out so as to be 5 cm × 5 cm × 10 μm thick in a dry state. The printed glass substrate was heated on a hot plate heated to 100 ° C for 30 minutes to obtain a cured layer. Then, the obtained hardened layer was visually observed. There is no coating defect (collapse) or unevenness on the cured layer, and the smooth surface is set to ○; there is a coating defect (collapse) or unevenness on the cured layer, and the surface is not smooth. ×.

The evaluation results of Examples 1 to 9 and Comparative Examples 1 to 2 are shown in Table 1. In addition, the unit of the numerical value of the composition column of Table 1 is "mass part."

As shown in Table 1, it is understood that the implementation of both the polyether compound and the leveling agent is included. In the cured layer of the thermosetting composition of Examples 1 to 9, the coating defects (collapsed) or irregularities were not present, and the smoothness of the surface was high. On the other hand, it is understood that the thermosetting composition of Comparative Example 1 containing no polyether compound and the cured layer of the thermosetting composition of Comparative Example 2 containing no leveling agent have coating defects (collapse). Or unevenness, and the smoothness of the surface is low.

Although the cured layer of the thermosetting composition of Examples 1 to 9 The reason why the smoothness of the surface is improved is not necessarily clear, but it is considered as follows. That is, it is considered that the reason is that in the process of heat-hardening the thermosetting composition, the ether bond portion of the polyether compound can capture the cation of the thermal cationic polymerization initiator and delay the cationic polymerization of the epoxy resin. And prolonging the time during which the thermosetting composition can flow. Thereby, the leveling agent can be sufficiently exerted during the heat curing of the thermosetting composition.

This application claims to be based on the Japanese patent application filed on June 10, 2013. May the priority of 2013-121808. The contents described in the specification and drawings of the application are all incorporated in the specification of the present application.

[Industrial availability]

According to the present invention, it is possible to provide a thermosetting composition which can form a cured layer having few irregularities, irregularities, and smoothness on the object to be coated, such as an organic EL element.

20‧‧‧Organic EL components

22‧‧‧Display substrate

24‧‧‧Organic EL components

26‧‧‧ Alignment substrate

28‧‧‧ Sealing members

30‧‧‧pixel electrode layer

32‧‧‧Organic EL layer

34‧‧‧ opposite electrode layer

Claims (11)

A thermosetting composition comprising: (A) a cationically polymerizable compound having two or more cationically polymerizable functional groups in one molecule; (B) a thermal cationic polymerization initiator; (C) a polyether compound (but , except for the compound having the cationically polymerizable functional group; and (D) a leveling agent; and the viscosity at 25 ° C and 2.5 rpm measured by an E-type viscometer is 50 mPa. s~30000mPa. s. The thermosetting composition according to claim 1, wherein the component (D) is a compound selected from the group consisting of an anthrone-based polymer and an acrylate-based polymer. The thermosetting composition according to claim 1, wherein the component (C) has a weight average molecular weight of from 250 to 10,000. The thermosetting composition according to claim 1, wherein the component (C) is contained in an amount of less than 10 parts by mass based on 100 parts by mass of the component (A). The thermosetting composition according to claim 1, wherein the cationically polymerizable functional group is one selected from the group consisting of an epoxy group, an oxetanyl group, and a vinyl ether group. Above base. The thermosetting composition according to claim 1, wherein the The component (B) is an onium salt. The thermosetting composition according to claim 1, wherein the component (C) is a polyalkylene oxide. The thermosetting composition according to claim 1, wherein the component (B) contains 0.1 parts by mass to 5 parts by mass, and the component (D), based on 100 parts by mass of the component (A). 0.01 parts by mass to 1 part by mass. The thermosetting composition according to claim 8, wherein the component (C) is contained in an amount of less than 10 parts by mass based on 100 parts by mass of the component (A). A surface sealant for an organic electroluminescence device comprising the thermosetting composition according to claim 1 of the patent application. A cured product which is a cured product of the face sealant according to claim 10 of the patent application.