Radiation-curable inkjet ink, organic EL element

Abstract

To provide a patterned organic EL light emitting element excellent in adhesion to a lower electrode after UV curing and insulation properties by using radiation curable inkjet ink including a component (A) having a specific structure and capable of holding stable light emission for a long term.SOLUTION: Radiation curable inkjet ink for forming the insulation layer of an organic EL device including a pair of electrodes consisting of a lower electrode and a counter electrode and an organic light emitting layer and insulation layer between the electrodes includes: a component (A) having a carbonyl group unit in which carbon atoms of two carbonyl groups having two ester bonds bond carbons of different α positions and the carbons of the α positions bond to each other; a (meth) acrylate component (B) having a (meth) acrylate group; and a photoinitiator.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a radiation-curable inkjet ink for forming an insulating layer of an organic electroluminescent element, and an organic electroluminescent element using the same.

Background Art

[0002] An electroluminescent element (hereinafter referred to as an EL element) has characteristics such as high visibility due to self-luminescence and excellent impact resistance because it is a completely solid element, and attempts have been made to use it as a light-emitting element in various display devices. In particular, organic EL elements having configurations such as cathode / light-emitting layer / hole injection layer / anode, cathode / electron injection layer / light-emitting layer / anode, cathode / electron injection layer / light-emitting layer / hole injection layer / anode, anode / light-emitting layer / electron injection layer / cathode, etc. have been developed. These have excellent characteristics such as (1) emitting light only by applying a low voltage, (2) obtaining high-brightness and high-efficiency light emission, and (3) enabling multicolor display, and research on light-emitting materials, charge injection layers, electrode materials, etc. is being actively conducted ("Applied Physics Letters", Vol. 51, p. 913 (1987); "Applied Physics Letters", Vol. 55, p. 1489 (1989); "Journal of Applied Physics", Vol. 65, p. 3610 (1989)). Conventionally, when manufacturing an organic EL element, the counter electrode of the element has been manufactured by a method of depositing an electrode on the light-emitting element formation portion by applying a mask on the substrate. However, there has been a problem that the pattern accuracy of the counter electrode deteriorates due to the overhang of the deposition. In addition, since the mask for forming the organic layer and the mask for forming the counter electrode are different, in a normal deposition apparatus without a mask exchange mechanism, it is necessary to break the vacuum once before forming the counter electrode, open the vacuum chamber, exchange the mask, or install the mask, and the process is complicated. In this case, the interface between the organic layer and the counter electrode is contaminated, and it has been difficult to obtain a good EL element with good uniformity and the like. Furthermore, in an organic EL element, an electrode of an alloy or mixture of magnesium and a second group element is often formed and used for the cathode by a binary evaporation method. However, when these are used for the counter electrode, when depositing the electrode, a sagging portion due to overflow occurs. Therefore, since the degree of overflow of magnesium and the second group element is different, the composition of this portion is shifted from the inside of the counter electrode surface, resulting in a problem that the light emission uniformity is impaired. To solve this problem, instead of preparing a pattern mask according to the structure of the light-emitting element and performing electrode deposition and organic layer deposition while changing the mask, a patterned interlayer insulating film is formed between the lower electrode and the counter electrode in the non-light-emitting element portion, and a manufacturing method has been proposed that has excellent pattern accuracy and requires only a minimum number of operations such as mask exchange.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] However, in the above invention, a photoresist of a polyimide-based material is used for forming the patterned interlayer insulating film. The photoresist is coated on the substrate, dried for 60 minutes, exposed to UV using a photomask and then developed. Although the number of complicated processes has decreased compared to the conventional method, operations such as the creation of the photomask still remain, and new management items such as the management of exposure, development, and cleaning have increased, making it difficult to say that it has become much simpler.

[0005] Therefore, the present inventors have conducted intensive studies to develop a manufacturing method for producing a patterned interlayer insulating film without using a photomask and without a development drying process. As a result, it has been found that an EL element provided with an interlayer insulating film patterned by an inkjet printing method can achieve the above object. The present invention has been completed based on such findings.

Means for Solving the Problems

[0006] That is, the present invention relates to a radiation-curable inkjet ink for forming an insulating layer of an organic EL element having a pair of electrodes composed of a lower electrode and a counter electrode and an organic light-emitting layer and an insulating layer between the electrodes, wherein the radiation-curable inkjet ink contains a component (A) having a carbonyl group unit in which the carbon atoms of two carbonyl groups of two ester bonds are each bonded to a carbon at a different α-position and the carbon atoms at the α-position are bonded to each other, a (meth)acrylate component (B) having a (meth)acrylate group, and a photopolymerization initiator.

[0007] The present invention also relates to the above-described radiation-curable inkjet ink, wherein the component (A) is any one represented by the following general formulas A1 to A11.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0008] Further, the present invention relates to the radiation-curable inkjet ink, wherein R in general formula A1 6 , and R in general formulas A2 to A11 6’ are the sites having the (meth)acrylate group represented by the general formula (1).

[0009] Further, the present invention relates to R in general formulas A1, A3 to A11 101The compound having one glycidyl ether in [the compound] is selected from the group consisting of allyl glycidyl ether, glycidyl phenyl ether which may have a substituent, alkyl glycidyl ether, and polyethylene glycidyl ether. R in general formula A2 102 Regarding the above radiation-curable inkjet ink, the compound having two glycidyl ethers in [the compound] is a bisphenol type epoxy compound.

[0010] Further, in the present invention, the dibasic acid monoanhydride in general formulas A1 and A2 is selected from the group consisting of succinic anhydride, maleic anhydride, phthalic anhydride, itaconic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, and cyclohexene-1,2-dicarboxylic anhydride, and derivatives of the above dibasic acid monoanhydride. Regarding the above radiation-curable inkjet ink, the tetrabasic acid dianhydride in general formula A11 is selected from the group consisting of dianhydrides of biphenyltetracarboxylic acids, dianhydrides of benzophenonetetracarboxylic acids, dianhydrides of diphenylethertetracarboxylic acids, and ethylene glycol bistrimellitic anhydride, and derivatives of the above tetrabasic acid dianhydrides.

[0011] Or, the present invention relates to an organic EL element having a pair of electrodes consisting of a lower electrode and a counter electrode and an organic light-emitting layer and an insulating layer between the electrodes, wherein the insulating layer is formed of a radiation-curable inkjet ink.

[0012] Further, the present invention relates to the above organic EL element, wherein the radiation-curable inkjet ink contains the above radiation-curable inkjet ink.

Effects of the Invention

[0013] By using a radiation-curable inkjet ink containing a component (A) having a specific structure, a patterned organic EL light-emitting device can be provided which, after UV curing, has excellent adhesion to the lower electrode and further excellent insulating properties, and thus retains stable light emission over a long period of time.

Brief Description of Drawings

[0014]

Figure 1

Embodiments for Carrying Out the Invention

[0015] The terms used in this specification will be explained. In the present invention, (meth)acrylate represents each of acrylate and methacrylate, and (meth)acryloyl group represents each of acryloyl group and methacryloyl group. Also, in the present invention, radiation-curable means the property of being curable by ionizing radiation and non-ionizing radiation including ultraviolet rays and visible light.

[0016] The organic electroluminescence element of the present invention is characterized in that the patterned interlayer insulating layer in the non-light-emitting portion formed between the electrodes is a cured product of a radiation-curable inkjet ink, and preferably a cured product of a radiation-curable inkjet ink containing a component (A) having a specific structure. That is, the radiation-curable inkjet ink in the present invention contains a component (A) having a carbonyl group unit in which the carbon atoms of two carbonyl groups in two ester bonds are each bonded to a carbon at a different α-position, and the α-position carbons are bonded to each other, thereby forming an insulating film having excellent adhesion to the base material and the electrode.

[0017] <Component (A)> Component (A) contains a "carbonyl group unit in which two carbonyl groups are bonded by -CC-". In the above -CC-, the carbon atoms of the two carbonyl groups are each bonded to a carbon at a different α-position, and the α-position carbons are bonded to each other, and it is a carbon having a carbonyl group unit. The said component (A) contributes to improving the adhesion to the base material and the electrode. Examples of the component (A) include those represented by the following general formulas A1 to A11.

[0018]

Chemical formula

[0019] R 101 : The remaining part after removing the glycidyl ether group from a compound having one glycidyl ether group. R 2 、R 3 、R 4 、R 5 : The remaining part after removing the anhydride group and two α-position carbons from a dibasic acid anhydride. However, R 2 、R 3 、R 4 、R 5 may be interconnected to form a ring. R 6 : An alkyl group, an aryl group, -R 7 -OH, -CH=CH2, -CH2CH=CH2, and any one selected from the group represented by the following general formulas (1) to (3).

Chemical formula

[0020] The component represented by the general formula A1 can be obtained, for example, by a two-step reaction as shown in the following synthetic scheme (image). That is, in the first step, a dibasic acid monoanhydride and a hydroxyl group-containing compound are subjected to an addition reaction to obtain an intermediate product having a carboxyl group, and in the second step, a compound having one glycidyl ether group is added to the intermediate product having a carboxyl group obtained in the first step. This is a two-step reaction. It is also possible to use a dibasic acid instead of the dibasic acid monoanhydride. Alternatively, in a preliminary step, another hydroxyl group-containing compound other than the hydroxyl group-containing compound to be incorporated into the structure of the component represented by the general formula A1 is reacted with a dibasic acid monoanhydride to form a preliminary intermediate product. In the first step, the hydroxyl group-containing compound to be incorporated into the structure of the component represented by the general formula A1 is reacted with the preliminary intermediate product (transesterification), and the other hydroxyl group-containing compound used in the preliminary step is distilled off. Then, in the second step, the component of the general formula A1 can also be obtained by adding a compound having one glycidyl ether group.

[0021] [Chemical formula]

[0022] [Dibasic acid monoanhydride] When obtaining the general formula A1, the dibasic acid monoanhydride used is a compound containing one acid anhydride group in the molecule, in which the carbon at the α-position of the two carbonyl groups is bonded to another carbon at the α-position, and the carbons at the α-position are bonded to each other. Examples of such dibasic acid monoanhydrides include succinic anhydride and its derivatives, maleic anhydride and its derivatives, phthalic anhydride and its derivatives, etc. In the case of phthalic anhydride and its derivatives, R in the general formula A1 2 , R 3 , R 4 , R 5They are interconnected to form a ring. In the present invention, only one kind of dibasic acid anhydride may be used alone, or a plurality of them may be used in combination.

[0023] Examples of the derivatives of succinic anhydride include alkyl succinic anhydrides such as butyl succinic anhydride, hexyl succinic anhydride, octyl succinic anhydride, and dodecyl succinic anhydride. Examples of the derivatives of maleic anhydride include alkyl maleic anhydrides such as butyl maleic anhydride, pentyl maleic anhydride, hexyl maleic anhydride, octyl maleic anhydride, decyl maleic anhydride, and dodecyl maleic anhydride.

[0024] Examples of the derivatives of phthalic anhydride include phthalic anhydride having a substituent, so-called hydrogenated phthalic anhydride in which at least a part of the aromatic ring of phthalic anhydride is hydrogenated, and hydrogenated phthalic anhydride having a substituent. Examples of phthalic anhydride having a substituent include tetrabromo phthalic anhydride. Examples of hydrogenated phthalic anhydride and hydrogenated phthalic anhydride having a substituent include tetrahydro phthalic anhydride, hexahydro phthalic anhydride, methyltetrahydro phthalic anhydride, nadic anhydride, methyl nadic anhydride, and hydrogenated methyl nadic anhydride.

[0025] [Hydroxyl group-containing compound] The hydroxyl group-containing compound that becomes a unit incorporated in the structure of general formula A1, that is, OH-R6, includes various monools and various diols.

[0026] Examples of the monool include aliphatic (saturated or unsaturated, straight-chain or branched) monools, alicyclic monools, aromatic monools, and the like. Saturated straight-chain aliphatic monohydric alcohols include, for example, methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, montan alcohol, and the like. Unsaturated straight-chain aliphatic monohydric alcohols include, for example, allyl alcohol, crotyl alcohol, oleyl alcohol, linoleyl alcohol, linolenyl alcohol, and the like. Saturated branched-chain aliphatic monohydric alcohols include, for example, isopropyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, 2-methyl-1-butanol, tert-pentyl alcohol, 2-ethylhexanol, isostearyl alcohol, triethylcarbinol, sec-butylcarbinol, and the like. Unsaturated branched-chain aliphatic monohydric alcohols include, for example, unsaturated branched-chain aliphatic monohydric alcohols such as methyl vinyl carbinol, 3-methyl-6-hexen-2-ol, 4-propyl-8-octadecene-1-ol, and the like. Aliphatic-substituted monohydric alcohols include, for example, 2-bromopropanol, 2-chloroethanol, and the like. Cycloaliphatic monohydric alcohols include, for example, cyclopentanol, cyclohexanol, cyclooctadecanol, 2-methylcyclohexanol, and the like. Aromatic monohydric alcohols include, for example, benzyl alcohol, α-phenylethyl alcohol, β-phenylethyl alcohol, diphenylcarbinol, triphenylcarbinol, cinnamyl alcohol, and the like. Monohydric alcohols include, for example, aliphatic (saturated or unsaturated, straight-chain or branched) monohydric alcohols, cycloaliphatic monohydric alcohols, aromatic monohydric alcohols, and the like. Saturated straight-chain aliphatic monohydric alcohols include, for example, methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, montan alcohol, and the like. Examples of the unsaturated straight-chain aliphatic monohydric alcohol include allyl alcohol, crotyl alcohol, oleyl alcohol, linoleyl alcohol, linolenyl alcohol, and the like. Examples of the saturated branched aliphatic monohydric alcohol include isopropyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, 2-methyl-1-butanol, tert-pentyl alcohol, 2-ethylhexanol, isostearyl alcohol, triethylcarbinol, sec-butylcarbinol, and the like. Examples of the unsaturated branched aliphatic monohydric alcohol include unsaturated branched aliphatic monohydric alcohols such as methyl vinyl carbinol, 3-methyl-6-hexen-2-ol, 4-propyl-8-octadecene-1-ol, and the like. Examples of the aliphatic substituted monohydric alcohol include 2-bromopropanol, 2-chloroethanol, and the like. Examples of the alicyclic monohydric alcohol include cyclopentanol, cyclohexanol, cyclooctadecanol, 2-methylcyclohexanol, and the like. Examples of the aromatic monohydric alcohol include benzyl alcohol, α-phenylethyl alcohol, β-phenylethyl alcohol, diphenylcarbinol, triphenylcarbinol, cinnamyl alcohol, and the like. Examples of the aromatic substituted monohydric alcohol include p-nitrobenzyl alcohol, p-methoxy-2-phenylethanol, p-bromobenzyl alcohol, 3-(p-chlorophenyl)butanol, and the like. Examples of the aromatic substituted monohydric alcohol include p-nitrobenzyl alcohol, p-methoxy-2-phenylethanol, p-bromobenzyl alcohol, 3-(p-chlorophenyl)butanol, and the like.

[0027] OH-R 6 When the monohydric alcohol is used as [OH-R], R in the component represented by the general formula A1, which is the product 6It becomes the remaining part after removing OH from each of the above-mentioned various monoalcohols. Examples of the remaining part after removing OH include an alkyl group (linear, branched, alicyclic), an unsaturated hydrocarbon group typified by an alkenyl group, and an aryl group. The alkyl group, unsaturated hydrocarbon group, and aryl group can each have a substituent.

[0028] Examples of the diol include chain aliphatic hydrocarbons having two hydroxyl groups such as ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-butyl-2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,3,5-trimethyl-1,3-pentanediol, 2-methyl-1,8-octanediol, 3,3'-dimethylolheptane, propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, octanediol, 3-butyl-3-ethyl-1,5-pentanediol, 2-ethyl-1,6-hexanediol, etc. In addition to the chain aliphatic hydrocarbons, those having a cyclic aliphatic hydrocarbon or an aryl group can also be appropriately used.

[0029] OH-R 6 When a diol is used as OH-R, R in the component represented by the general formula A1, which is the product 6 is, as shown in the following formula, the remaining part after removing one OH from each of the above-mentioned various diols, that is, -R 7 -OH. R, which is the remaining part after removing one OH from -R 7 -OH 7 is the remaining part after removing two OHs from the aforementioned diol, that is, an alkylene group.

[0030]

Chemical formula

[0031] R 6 The case where R is of the general formula (1) will be described. React a diol with a dibasic acid anhydride -R 7 - to obtain an intermediate product having -OH and a carboxyl group, react a compound having one glycidyl ether group with the carboxyl group in the intermediate product, and then react a compound having a carboxyl group and a (meth)acryloyl group with -R 7 -OH to obtain a compound represented by the following formula. Examples of the compound having a carboxyl group and a (meth)acryloyl group include acrylic acid, methacrylic acid, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl phthalic acid, and the like.

[0032] [Chemical formula]

[0033] Alternatively, react a dibasic acid anhydride with a monoalcohol having a (meth)acryloyl group as a monoalcohol to obtain an intermediate product having a carboxyl group, and react a compound having one glycidyl ether group with the carboxyl group in the intermediate product to obtain a similar product. Examples of the monoalcohol having a (meth)acryloyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like. The monoalcohol having a (meth)acryloyl group can be obtained by reacting (meth)acrylic acid with a diol.

[0034] [Compound having one glycidyl ether group] Examples of the compound having one glycidyl ether group to be reacted with the intermediate product of a dibasic acid anhydride and a hydroxyl group-containing compound include allyl glycidyl ether, glycidyl phenyl ether, alkyl glycidyl ether, polyethylene glycidyl ether, glycidyl ether having a (meth)acryloyl group, and the like. Examples of the alkyl glycidyl ether include butyl glycidyl ether, 2-ethylhexyl glycidyl ether, p-tert butylphenyl glycidyl ether, and the like. Examples of the glycidyl ether having a (meth)acryloyl group include glycidyl (meth)acrylate and oxyalkylene (meth)acrylate glycidyl ether such as 4-hydroxybutyl (meth)acrylate glycidyl ether. As the compound having one glycidyl ether group, if a compound having one (meth)acryloyl group and one glycidyl ether group is used, 101 a (meth)acryloyl group can also be introduced into R. Two or more compounds having one glycidyl ether group can also be used in combination.

[0035] R 6 The case where R is of the general formula (2) will be described. When reacting with the dibasic acid anhydride, water can also be used instead of the aforementioned monool or diol. In this case, the intermediate product by the reaction of the dibasic acid anhydride and water becomes a dicarboxylic acid as shown in the following formula. When a compound having one glycidyl ether group in an amount equivalent to the carboxyl group in such a reaction product is reacted, a compound having a portion derived from the compound having one glycidyl ether group at both ends of the portion derived from the dibasic acid anhydride can be obtained. That is, R 6 a compound of the general formula (2) can be obtained. Examples of the compound having one glycidyl ether group can be the same as those mentioned above.

[0036]

Chemical formula

[0037] R 6 The case where R is of the general formula (3) will be described. As shown in the following formula, by reacting a dicarboxylic acid, which is an intermediate product obtained by the reaction of a dibasic acid anhydride and water, with a glycidyl ether having one (meth)acryloyl group, R 6 a compound of the general formula (3) can be obtained. It is also possible to react only the glycidyl ether having a (meth)acryloyl group, or it is also possible to use in combination the glycidyl ether having a (meth)acryloyl group and a compound having one other glycidyl ether group. Examples of the glycidyl ether having a (meth)acryloyl group and the compound having one other glycidyl ether group are the same as those described above.

[0038]

Chemical formula

[0039] When glycidyl (meth)acrylate is used as the glycidyl ether having a (meth)acryloyl group, R 8 becomes a direct bond.

[0040] Also, when an oxyalkylene (meth)acrylate glycidyl ether such as 4-hydroxybutyl (meth)acrylate glycidyl ether is used as the glycidyl ether having a (meth)acryloyl group, R 8 becomes -O-R 10 -, and R 10 becomes an alkylene group having no substituent.

[0041]

Chemical formula

[0042] <General formula A2> General formula A2

Chem.

[0043] R 102 : The remaining part after removing two glycidyl ether groups from a compound having two glycidyl ether groups R 2 、R 3 、R 4 、R 5 、R 7 are the same as in the case of general formula A1. R 6’ : Hydrogen, alkyl group, aryl group, -CH=CH2, -CH2CH=CH2, and any one selected from the group represented by the general formulas (1) and (3). m 1 、m 2 are each independently a number of 0 or more. However, when both m 1 and m 2 are 0, R 6’ is other than hydrogen.

[0044] <General formula A2-1> The case where m = 0 is shown as general formula A2-1.

Chem.

[0045] The component represented by general formula A2-1 can be obtained, for example, by a two-step reaction as shown in the following synthesis scheme (image). That is, similar to the case of general formula A1, in the first step, a dibasic acid anhydride and a hydroxyl group-containing compound are subjected to an addition reaction to obtain an intermediate product having a carboxyl group. In the second step, 2 mol of the intermediate product having a carboxyl group obtained in the first step is added to 1 mol of a compound having two glycidyl ether groups, and a compound represented by general formula A2-1 can be obtained. In addition, similar to the case of general formula A1, it is also possible to use dibasic acid instead of dibasic acid monoanhydride, or to use transesterification reaction after a preliminary stage. In addition, as in the case of general formula A1, the same compounds can be exemplified as the dibasic acid monoanhydride and the hydroxyl group-containing compound.

[0046]

Chemical formula

[0047] <General formula A2-2> Among the components represented by general formula A2, the component where m = 0 and R 6’ is the general formula (1) can be obtained by a two-step reaction, for example, as shown in the following synthesis scheme (image). That is, in the first step, a compound having a hydroxyl group and a (meth)acryloyl group is reacted with a dibasic acid monoanhydride to obtain an intermediate product having a carboxyl group and a (meth)acryloyl group. Then, in the second step, 2 mol of the intermediate product having a carboxyl group obtained in the first step is added to 1 mol of a compound having two glycidyl ether groups to obtain a compound represented by general formula A2-2. In addition, similar to the case of general formula A1, it is also possible to use dibasic acid instead of dibasic acid monoanhydride, or to use transesterification reaction after a preliminary stage.

[0048]

Chemical formula

[0049] <General formula A2-3>, <General formula A2-4> The case where m = 1 or more among the components represented by general formula A2 will be described. For example, as shown in the following image formula, a polyester with a carboxyl group terminal is obtained by reacting a dibasic acid monoanhydride and a diol in the first step. The degree of polymerization of the polyester can be adjusted according to the reaction conditions. Next, as the second step, the carboxyl groups in the carboxyl group-terminated polyester obtained in the first step are added to the epoxy groups in the compound having two glycidyl ether groups under conditions where the number of carboxyl groups increases, to obtain an intermediate product having a carboxyl group-terminated represented by the general formula A2-3. The degree of polymerization of the intermediate product having a carboxyl group-terminated can be appropriately adjusted according to the reaction conditions. The intermediate product having a carboxyl group-terminated represented by the general formula A2-3 can also be used as it is as the component (A). Furthermore, as the third step, 2 moles of the hydroxyl group in the compound having an epoxy group and a (meth)acryloyl group are reacted with 1 mole of the carboxyl group in the intermediate product having a carboxyl group-terminated represented by the general formula A2-3 to obtain a product having a (meth)acryloyl group represented by the general formula A2-4, and the product can also be used as the component (A).

[0050]

Chemical formula

[0051] <General formula A2-5> Alternatively, as the third step, 1 mole of the glycidyl ether group in the compound having a (meth)acryloyl group and a glycidyl ether group is reacted with 1 mole of the carboxyl group in the intermediate product A2-3 having a carboxyl group-terminated represented by the general formula A2-3 to obtain a product having a (meth)acryloyl group represented by the general formula A2-5, and the product can also be used as the component (A). In addition, similar to the case of the general formula A1, a dibasic acid can be used instead of the dibasic acid monoanhydride, or a transesterification reaction can be used after a preliminary step. In addition, examples of the dibasic acid monoanhydride, diol, compound having a hydroxyl group and a (meth)acryloyl group, and compound having a (meth)acryloyl group and a glycidyl ether group are the same as those in the case of the general formula A1.

[0052]

Chemical formula

[0053] [Compound having two glycidyl ether groups] Examples of the compound having two glycidyl ether groups include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, diglycidyl ether of neopentyl glycol, bisphenol-type diglycidyl ether, and the like.

[0054] Also, a product (a kind of dimer) formed by bonding two molecules of a compound having two glycidyl ether groups via an amine can also be used as a compound having two glycidyl ether groups.

[0055] <General formula A3,4> [Chemical formula] R 101 is the same as in the case of general formula A1. R 6’ is the same as in the case of general formula A2.

[0056] The components represented by general formulas A3 and A4 can be obtained, for example, by a two-step reaction as shown in the following synthesis scheme (image). That is, in the first step, a hydroxyl group-containing compound is added to trimellitic anhydride to produce a monoester compound (intermediate product) having two carboxyl groups. The obtained intermediate product is considered to contain isomers. In the following scheme, the meaning of containing isomers is represented by "+". In the second step, 1 mol of the intermediate product having two carboxyl groups obtained in the first step is reacted with 2 mol of a compound having one glycidyl ether group to obtain a compound represented by general formulas A3 and A4. Note that, similar to the case of general formula A1, trimellitic acid can be used instead of trimellitic anhydride, or a transesterification reaction can be used after a preliminary step. In addition, examples of the hydroxyl group-containing compound can be the same as those in the case of General Formula A1.

[0057]

Chemical formula

[0058] In the present invention, in addition to the compounds represented by General Formulas A3 and A4, as the tribasic acid anhydride, hydrogenated trimellitic anhydride or trimellitic anhydride having a substituent can also be used as component (A).

[0059] <General Formulas A5, A6>

Chemical formula

[0060] The components represented by General Formulas A5 and A6 can be obtained by a two-step reaction, for example, as shown in the following synthesis scheme (image). That is, in the first step, 2 equivalents of the hydroxyl group-containing compound are added to 1 equivalent of pyromellitic anhydride to form a diester compound (intermediate product) having two carboxyl groups. The obtained intermediate product is considered to contain isomers. In the following scheme, the meaning of containing isomers is represented by "+". In the second step, 1 mol of the intermediate product having two carboxyl groups obtained in the first step is reacted with 2 mol of the compound having one glycidyl ether group to obtain the compound represented by General Formulas A5 and A6. In the following scheme, the amount ratio of the reaction between the compound having one glycidyl ether group and the intermediate product is omitted. In addition, the components represented by General Formulas A5 and A6 are the same as those of the components represented by General Formulas A3 and A4, except that pyromellitic anhydride is used instead of trimellitic anhydride.

[0061] [Chemical formula]

[0062] <General formula A7, A8> [Chemical formula] R 101 is the same as in the case of general formula A1. R 6’ is the same as in the case of general formula A2.

[0063] The components represented by general formulas A7 and A8 can be obtained, for example, by a two-step reaction as shown in the following synthesis scheme (image). A7 and A8 are the same as in the case of A5 and A6, except that pyromellitic dianhydride becomes trimellitic anhydride.

[0064] [Chemical formula]

[0065] <General formula A9, A10> [Chemical formula] R 101 is the same as in the case of general formula A1. R 6’ is the same as in the case of general formula A2.

[0066] The components represented by general formulas A9 and A10 can be obtained, for example, by a two-step reaction as shown in the following synthesis scheme (image). A9 and A10 are the same as in the case of A5 and A6, except that pyromellitic dianhydride becomes butane-1,2,3,4-tetracarboxylic dianhydride.

[0067] [Chemical formula]

[0068] <General formula A11> [Chemical formula] R 200 : The remaining part after removing two anhydride groups and four α-carbon atoms from the tetracarboxylic dianhydride. However, the bond between the α-carbon atoms can form part of an aromatic ring. R 101 is the same as in the case of general formula A1. R 6’ is the same as in the case of general formula A2.

[0069] The component represented by general formula A11 will be described. The component represented by general formula A11 uses, as the tetracarboxylic dianhydride, two sets of dibasic acid dianhydride groups connected by a rotatable bond. Examples of those having two sets of dibasic acid dianhydride groups connected to a rotatable axis include dianhydrides of biphenyltetracarboxylic acids, dianhydrides of benzophenonetetracarboxylic acids, dianhydrides of diphenyl ether tetracarboxylic acids, and ethylene glycol bistrimellitic anhydride, etc. Furthermore, derivatives such as tetracarboxylic dianhydrides having so-called hydrogenated substituents in which hydrogen is added to the aromatic ring of the dianhydrides of biphenyltetracarboxylic acids, etc. are also included.

[0070] Examples of the dianhydrides of biphenyltetracarboxylic acids include 2,2’,3,3’-biphenyltetracarboxylic acid 2,3:2’,3’-dianhydride (alias: 1,1’-biphenyl-2,2’,3,3’-tetracarboxylic acid 2,3:2’,3’ dianhydride), 3,3’,4,4’-biphenyltetracarboxylic acid dianhydride, 4,4‘-phthalic anhydride (alias: 1,1’-biphenyl-3,3’,4,4’-tetracarboxylic acid), etc.

[0071] Examples of the benzophenone tetracarboxylic dianhydrides include 3,3’,4,4’-benzophenone tetracarboxylic dianhydride and the like. Examples of the diphenyl ether tetracarboxylic dianhydrides include 4,4’-oxybisphthalic 1,2:1’,2’-dianhydride (also known as 3,3‘,4,4’-diphenyl ether tetracarboxylic dianhydride), 3,4’-oxybisphthalic 1,2:1’,2’-dianhydride and the like.

[0072] In addition to these, examples of the two sets of dibasic acid dianhydrides connected by a rotatable bond include ethylene glycol bistrimellitic anhydride, 4,4’-(hexafluoroisopropylidene)diphthalic anhydride, 3,3’,4,4’-diphenylsulfone tetracarboxylic dianhydride, 3,3’,4,4’-diphenylsulfone tetracarboxylic anhydride and the like. Furthermore, examples of those having two sets of dibasic acid dianhydride groups connected by a rotatable bond include so-called hydrogenated products in which hydrogen is added to the aromatic ring of the above-described various tetracarboxylic dianhydrides and those having substituents.

[0073] Taking 3,3’,4,4’-benzophenone tetracarboxylic dianhydride (hereinafter referred to as BPDA) as an example of those having two sets of dibasic acid dianhydride groups connected by a rotatable bond, a method for obtaining a component represented by general formula A11 and a component represented by general formula A11-1 will be described. Similar to the cases of general formulas A5 and A6 using pyromellitic dianhydride, first, in the first step, 2 equivalents of a hydroxyl group-containing compound are added to 1 equivalent of BPDA for an addition reaction to produce a diester compound (intermediate product) having two carboxyl groups. In the second step, 1 mol of the intermediate product having two carboxyl groups obtained in the first step is reacted with 2 mol of a compound having one glycidyl ether group to obtain a compound represented by general formula A7. In the following scheme, the molar ratio of the reaction between the compound having one glycidyl ether group and the intermediate product is omitted. In addition, the component represented by General Formula A7 is the same as the components represented by General Formulas A3 and A4, except that BPDA is used instead of pyromellitic dianhydride.

[0074] [Chemical Formula]

[0075] In the present invention, component (A) is preferably photocurable. That is, R in General Formulas A1 to A11 6 and R 6’ are preferably components represented by General Formula (1) or (3), and more preferably a component represented by General Formula (1).

[0076] [Chemical Formula]

[0077] Component (A) is preferably 1 to 35 parts by mass, more preferably 2 to 25 parts by mass, relative to 100 parts by mass of component (B) described below.

[0078] <Component (B)> Component (B) is a component having one or more (meth)acryloyl groups, and the carbon atoms of the two carbonyl groups in the two ester bonds are each bonded to a carbon atom at a different α-position, and the α-carbon atoms are not bonded to each other to form a carbonyl group unit.

[0079] Examples of component (B) include monofunctional, difunctional, trifunctional, and those having four or more functional groups, and they can be used alone or in appropriate combination of two or more. When using two or more types, it is preferably a combination of a difunctional and a trifunctional one.

[0080] Examples of monofunctional compounds, i.e., compounds having one (meth)acryloyl group, include ester compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, tetrafurfuryl (meth)acrylate, lauryl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, 2-(meth)acryloyloxyethyl acid phosphate, styrene-based compounds such as styrene and α-methylene, silane compounds such as γ-(meth)acryloxypropyltrimethoxysilane and γ-(meth)acryloxypropyltriethoxysilane, nitrogen-containing compounds such as 2-(N,N-dimethylamino)ethyl (meth)acrylate, N-methylol (meth)acrylamide, and acryloylmorpholine, fluorine-containing compounds such as trifluoroethyl (meth)acrylate and 2,2,3,3,3-pentafluoropropyl (meth)acrylate, and polymerizable silicone compounds in which the main chain of the polymer is a silicone component and one end is modified with a (meth)acrylate group.

[0081] Examples of the compound having two functional groups, i.e., two (meth)acryloyl groups, include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6 - hexanediol di(meth)acrylate, ethoxylated 1,6 - hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,4 - butanediol di(meth)acrylate, 1,9 - nonanediol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 2 - n - butyl - 2 - ethyl - 1,3 - propanediol di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, methyl 2-(allyloxymethyl)acrylate, 1,3 - butylene glycol di(meth)acrylate, ethoxylated tripropylene glycol di(meth)acrylate, neopentyl glycol - modified trimethylolpropane di(meth)acrylate, stearic acid - modified pentaerythritol di(meth)acrylate, tripropylene glycol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol F di(meth)acrylate, cyclohexanedimethanol (meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, isocyanuric acid di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate.

[0082] Examples of the compound having three functional groups, i.e., three (meth)acryloyl groups, include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerin tri(meth)acrylate, tetramethylolpropane tri(meth)acrylate, caprolactone - modified trimethylolpropane tri(meth)acrylate, tri(2 - hydroxyethyl isocyanurate) tri(meth)acrylate.

[0083] Examples of the (meth)acrylate compound having four or more functional groups include ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and dipentaerythritol penta(meth)acrylate. These polyfunctional (meth)acrylate compounds may be used alone or, if necessary, in combination of two or more. In the case of polyfunctional compounds, those having only acryloyl groups, those having only methacryloyl groups, and those having both acryloyl groups and methacryloyl groups are conceivable, and any of them may be used.

[0084] <Photoinitiator> A photoinitiator is used for curing by light in the present invention. The photoinitiator is preferably a photo radical polymerization initiator. The photo radical polymerization initiator is preferably of the intramolecular cleavage type or the hydrogen abstraction type. The intramolecular cleavage type photo radical polymerization initiator is a type of radical initiator in which the initiator molecule cleaves upon irradiation with radiation to generate radicals. Examples of the intramolecular cleavage type photo radical polymerization initiator include benzyl ketal-based photo radical polymerization initiators, α-hydroxyacetophenone-based photo radical polymerization initiators, benzoin-based photo radical polymerization initiators, aminoacetophenone-based photo initiators, oxime ketone-based photo radical polymerization initiators, acylphosphine oxide-based photo radical polymerization initiators, titanocene-based photo radical polymerization initiators, and the like. The photoinitiator can be used alone or in combination of two or more.

[0085] Examples of the benzyl ketal-based photo radical polymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one (benzyl dimethyl ketal / 2,2-dimethoxy-2-phenylacetophenone). α-Hydroxyacetophenone-based photoinitiators for radical polymerization include, for example, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 1-(4-dodecylbenzoyl)-1-hydroxy-1-methylethane, 1-(4-isopropylbenzoyl)-1-hydroxy-1-methylethane, 1-benzoyl-1-hydroxy-1-methylethane, 1-[4-(2-hydroxyethoxy)-benzoyl]-1-hydroxy-1-methylethane, 1-[4-(acryloyloxyethoxy)-benzoyl]-1-hydroxy-1-methylethane, phenyl-1-hydroxy-cyclohexylketone, 2-hydroxy-2-methyl-[4-(1-methylvinyl)phenyl]propanol oligomer, and the like. Benzoin-based photoinitiators for radical polymerization include, for example, benzoin, benzoin isobutyl ether, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether, and the like. Aminoacetophenone-based photoinitiators for radical polymerization include, for example, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and the like. Oxime ketone-based photoinitiators for radical polymerization include, for example, 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetoxime), and the like. Acylphosphine oxide-based photoinitiators for radical polymerization include, for example, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and the like. Examples of titanocene-based photo radical polymerization initiators include bis(cyclopentadienyl)-di-phenyl-titanium, bis(cyclopentadienyl)-di-chloro-titanium, bis(cyclopentadienyl)-bis(2,3,4,5,6-pentafluorophenyl)titanium, bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyrrol-1-yl)phenyl)titanium, and the like.

[0086] As the hydrogen abstraction type photo radical polymerization initiator, benzophenone-based photo radical initiators, thioxanthone-based photo radical polymerization initiators, anthraquinone-based photo initiators, and the like are preferable. Examples of benzophenone-based photo radical initiators include benzophenone, 4-methylbenzophenone, 3-benzoylbiphenyl, 4-(4-methylphenylthio)benzophenone, methyl 2-benzoylbenzoate, 4-phenylbenzophenone, 4,4'-bis(dimethoxy)benzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, methyl 2-benzoylbenzoate, 2-methylbenzophenone, 3-methylbenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2,4,6-trimethylbenzophenone and other benzophenone derivatives, 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)-propan-1-one, and the like. Examples of thioxanthone-based photo radical polymerization initiators include thioxanthone, xanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 1-chloro-4-propoxythioxanthone, 2,4-diethylthioxanthen-9-one and other thioxanthone derivatives, and the like. Examples of anthraquinone-based photo initiators include anthraquinone, 2-ethylanthraquinone, 2-hydroxyanthraquinone, 2-aminoanthraquinone, and the like.

[0087] Among these, it is preferable to use acylphosphine-based compounds as the photoinitiator. Examples of acylphosphine-based compounds include acylphosphine oxide-based photo radical polymerization initiators. Among them, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide are preferable. As the acylphosphine-based compound, a commercially available product may be used. For example, Omnirad TPO (manufactured by IGM Resins B.V.), Omnirad 819 (manufactured by IGM Resins B.V.) and the like can be preferably used. The photoinitiator preferably contains 1 to 20 parts by mass with respect to 100 parts by mass of component (B).

[0088] <Sensitizer> In the radiation-curable inkjet ink of the present invention, a sensitizer can be used in combination with the photoinitiator. Examples of the sensitizer include amine-based sensitizers, anthracene-based sensitizers, thioxanthone-based sensitizers and the like. The sensitizer can be used alone or in combination of two or more. Examples of the amine-based sensitizer include trimethylamine, methyldiethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, N,N-dimethylbenzylamine, 4'-bis(diethylamino)benzophenone and the like. Examples of the anthracene-based sensitizer include 9,10-dibutoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-bis(2-ethylhexyloxy)anthracene and the like. Examples of thioxanthone-based sensitizers include thioxanthone-based sensitizers such as 2,4-diethylthioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone. Representative examples of commercially available products include EPA (manufactured by Nippon Kayaku Co., Ltd.) for amine-based sensitizers, DBA and DEA (manufactured by Kawasaki Kasei Kogyo Co., Ltd.) for anthracene-based sensitizers, and DETX and ITX (manufactured by Lambson) for thioxanthone-based sensitizers. The sensitizer is preferably a thioxanthone-based sensitizer or the like. The sensitizer preferably contains 0.1 to 5 parts by mass with respect to 100 parts by mass of component (B).

[0089] <Resin> The radiation-curable inkjet ink in the present invention can contain a resin. By including a resin in the composition, the hardness, flexibility, etc. of the organic protective layer can be appropriately adjusted. Examples of the resin include acrylic resin, epoxy resin, polyurethane resin, polyurethane urea resin, (modified) styrene maleic anhydride copolymer, (modified) vinyl chloride vinyl acetate copolymer, (modified) vinyl chloride vinyl acetate maleic anhydride copolymer, ketone aldehyde resin, polyester resin, polypropylene resin, polylactic acid resin, cellulose acetate resin, cellulose acetate butyrate resin, esterified cellulose resin, butyral resin, and the like. These resins can be used alone or in combination of two or more. The resin preferably contains 1 to 35 parts by mass with respect to 100 parts by mass of component (B).

[0090] <Other Additives> The radiation-curable inkjet ink in the present invention can contain other additives as necessary. Examples of other additives include plasticizers, surface modifiers, light stabilizers, antioxidants, and polymerization inhibitors.

[0091] The radiation-curable inkjet ink in the present invention may use a polymerization inhibitor from the viewpoint of improving storage stability. The polymerization inhibitor can be appropriately selected and used from known ones. Examples of the polymerization inhibitor include hindered phenols, hindered amines, quinones, nitrosoamines, phenothiazines, piperidine-1-oxyls, etc. Among them, piperidinedi(piperidine-1-oxyls) are preferred, and among them, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl is more preferred. As 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, for example, Polystop P7300 manufactured by Hakuto Co., Ltd. can be used. When using the polymerization inhibitor, its content ratio is preferably 0.001% by mass or more and 0.2% by mass or less, more preferably 0.01% by mass or more and 0.1% by mass or less, based on 100 parts by mass of component (B), from the viewpoint of achieving both storage stability and photocurability.

[0092] In addition, the radiation-curable inkjet ink can contain an inorganic compound as long as it can solve the problems when used for forming an organic protective layer.

[0093] The radiation-curable inkjet ink of the present invention can be produced by blending component (A), component (B), and a photoinitiator and mixing them with a stirrer. As the stirrer, a known stirring device such as a disperser can be used.

[0094] The radiation-curable inkjet ink can be rapidly cured by light and can form an organic layer having excellent adhesion to a layer containing an inorganic compound in particular. Therefore, it can be suitably used for forming an organic protective layer of an insulating layer formed on a base material and an electrode constituting an organic EL element.

[0095] (Method for preparing the composition) The radiation-curable inkjet ink of the present invention can be produced by adding component (A), component (B), a photoinitiator, and optionally a resin, various additives, etc., and mixing them with a stirrer such as a disper while heating if necessary. The produced inkjet ink must be filtered through a filter with a pore size of 3 μm or less, preferably 1 μm or less, in order to prevent clogging at the head during printing.

[0096] In one embodiment, the ink composition of the present invention preferably has a viscosity at 25 °C of 5 to 50 mPa·s, more preferably 5 to 30 mPa·s. By adjusting the viscosity of the ink composition within the above range, stable ejection characteristics can be obtained not only with a normal head having a frequency of 5 to 30 KHz but also with a high-frequency head having a frequency of 10 to 50 KHz. More specifically, when the viscosity of the ink composition is 5 mPa·s or more, it is difficult for the followability of ejection to decrease even with a high-frequency head. On the other hand, when the viscosity is 50 mPa·s or less, even if a mechanism for reducing the viscosity by heating is incorporated into the head, a problem that the ejection itself decreases and the ejection stability becomes poor and ejection cannot be performed at all hardly occurs.

[0097] The ink composition of the present invention can be used as an ink for a printer using a normal inkjet recording method. A typical method includes a step of supplying the ink composition to a printer head of a printer for an inkjet recording method, a step of ejecting the ink composition from this printer head onto a substrate, and then a step of irradiating the ink composition on the substrate with an active energy ray such as ultraviolet rays or electron beams. By irradiating the active energy ray, the ink composition on the substrate is quickly cured and a printed surface is formed.

[0098] In one embodiment, it is preferable to irradiate ultraviolet rays as a light source of the active energy ray. In this case, as the light source, for example, a high-pressure mercury lamp, a metal halide lamp, a low-pressure mercury lamp, an ultra-high-pressure mercury lamp, an ultraviolet laser, a gallium lamp, an LED, and sunlight can be used.

[0099] The ultraviolet rays preferably fall within the range of 350 nm to 450 nm. Also, the irradiation dose of the ultraviolet rays is preferably 10 mJ / cm2 or more and 10,000 mJ / cm2 or less. In particular, according to the ink composition of the present invention, since the solubility of acylphosphine oxide is improved, the content of the photoinitiator in the ink composition can be sufficiently increased. Therefore, even when the irradiation dose of the ultraviolet rays is low, sufficient curability is expected to be obtained. Thus, sufficient curability can be obtained regardless of whether a generally widely used metal halide lamp or LED lamp is used.

[0100] As shown in FIG. 1, the organic EL element of the present invention has a structure including a lower electrode (usually an anode) formed on a substrate of the element, an organic multilayer portion including a light-emitting layer, and a counter electrode (usually a cathode) formed thereon in the light-emitting element portion, and is characterized in that an interlayer insulating film patterned between the lower electrode and the counter electrode is provided in the non-light-emitting portion. Here, the patterned interlayer insulating film is an insulating film between the lower electrode and the counter electrode provided in the portion where the light-emitting element is not formed (non-light-emitting element portion) with the portion where the light-emitting element is formed (light-emitting element portion) as an opening. When a light-emitting material layer and a counter electrode are formed on the lower electrode on which the patterned insulating film is formed, current can only flow through the openings where the patterned insulating film is not formed, and light emission with good pattern accuracy can be obtained only in that portion. It is preferable to use a radiation-curable inkjet ink excellent in adhesion between the lower electrode of the present invention and the substrate for this interlayer insulating film. The inkjet printing apparatus is not particularly limited, and general-purpose test or industrial ones are used. Pattern printing is performed on the substrate on which the lower electrode is formed by an inkjet printer programmed in advance with the pattern of the non-light-emitting portion, and after printing, radiation curing is quickly performed to form the interlayer insulating film. The thickness of the insulating film is not particularly limited, but is usually 0.5 to 10 μm. If it is less than 0.5 μm, there may be a problem with insulation. If it exceeds 10 μm, the step at the edge of the insulating film opening becomes large, making it difficult to form the light-emitting layer and the upper electrode.

[0101] The details of each element other than the insulating film constituting the organic EL element of the present invention will be described below. <Organic EL element> As the substrate, a known substrate used for an organic EL element can be widely adopted. The substrate may be a glass plate, a resin film, or a gas barrier film. Gas barrier films described in JP-A-2004-136466, JP-A-2004-148566, JP-A-2005-246716, JP-A-2005-262529, etc. can also be preferably used.

[0102] In the case of cellulose esters, for example, diacetyl cellulose, triacetyl cellulose (TAC), propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, nitrocellulose, etc.; In the case of polyesters, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, poly-1,4-cyclohexanedimethylene terephthalate, polyethylene-1,2-diphenoxyethane-4,4'-dicarboxylate, polybutylene terephthalate, etc.; In the case of polyolefins, for example, polyethylene, polypropylene (PP), polymethylpentene, polytetrafluoroethylene, cycloolefin polymer (COP), etc.; In the case of vinyl compounds, for example, polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride, polyvinyl fluoride, etc.; In the case of acrylic resins, for example, polymethyl methacrylate (PMMA), polyacrylate ester, etc.; Others include, for example, polystyrene (PS), polycarbonate (PC), polyamide, polyimide (PI), polyurethane, polysulfone, polyethersulfone, polyetherketone, polyetherimide, polyoxyethylene, norbornene resin, AS resin (SAN), polyvinylidene chloride resin (PVDC), epoxy resin, etc., and glass. Among these, polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin polymer (COP), and polyimide (PI) are preferred.

[0103] The thickness of the substrate is usually about 5 μm to 700 μm, preferably 10 μm to 200 μm, and more preferably 15 μm to 150 μm. The substrate 21 preferably has a haze of 3% or less, preferably 2% or less, and more preferably 1% or less. Further, the base material 21 preferably has a total light transmittance of 70% or more, more preferably 80% or more, and even more preferably 90% or more. Satisfying the haze and the total light transmittance improves the visibility of the OLED.

[0104] The organic EL element has a substrate and a pair of electrodes constituting a cathode and an anode provided on the substrate, and an organic light-emitting layer including a light-emitting layer is provided between the two electrodes. As an example, one electrode can be the anode and the other electrode can be the cathode. Due to the nature of the light-emitting element, at least one of the anode and the cathode is transparent. The anode usually only needs to have a function as an electrode that supplies holes to the organic compound layer, and there are no particular restrictions on its shape, structure, size, etc. It can be appropriately selected from known electrode materials according to the use and purpose of the light-emitting element. The anode is usually provided as a transparent anode. When using a plastic base material with low heat resistance as the substrate, indium tin oxide (hereinafter, ITO) or indium zinc oxide (hereinafter, IZO) is used, and a transparent anode formed at a low temperature of 150 °C or lower is preferred.

[0105] The cathode usually only needs to have a function as an electrode that injects electrons into the organic compound layer, and there are no particular restrictions on its shape, structure, size, etc. It can be appropriately selected from known electrode materials according to the use and purpose of the light-emitting element. Materials constituting the cathode include, for example, metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Examples of such materials include second group metals (such as Mg, Ca, etc.), gold, silver, lead, aluminum, lithium-aluminum alloy, magnesium-silver alloy, indium, and rare earth metals such as ytterbium. These can be used alone or in combination of two or more. As the material constituting the cathode, a material mainly composed of aluminum is preferred. The material mainly composed of aluminum refers to aluminum alone or an alloy of aluminum and 0.01 to 10% by mass of an alkali metal or a second group metal (such as lithium-aluminum alloy, magnesium-aluminum alloy, etc.). Note that the materials of the cathode are described in detail in JP-A-2-15595 and JP-A-5-121172. Also, a dielectric layer made of a fluoride, oxide, etc. of an alkali metal or a second group metal may be inserted between the cathode and the organic compound layer with a thickness of 0.1 to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer.

[0106] The thickness of the cathode is usually about 10 nm to 5 μm, and preferably 50 nm to 1 μm. Also, the cathode may be transparent or opaque. The transparent cathode can be formed by thinly depositing the cathode material to a thickness of 1 to 10 nm and further laminating a transparent conductive material such as ITO or IZO.

[0107] Although illustration is omitted, as the lamination mode of the organic compound layer, a mode in which a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode are laminated in this order from the anode side is preferred. Further, a charge blocking layer or the like may be provided between the hole transport layer and the light-emitting layer, or between the light-emitting layer and the electron transport layer. A hole injection layer may be provided between the anode and the hole transport layer, and an electron injection layer may be provided between the cathode and the electron transport layer. Also, the light-emitting layer may be a single layer, or the light-emitting layer may be divided into a first light-emitting layer, a second light-emitting layer, a third light-emitting layer, etc. Further, each layer may be divided into a plurality of secondary layers.

[0108] The organic EL element has at least one organic compound layer including a light-emitting layer. As the other organic compound layers other than the organic light-emitting layer, as described above, there are layers such as a hole transport layer, an electron transport layer, a charge blocking layer, a hole injection layer, and an electron injection layer.

[0109] The organic light-emitting layer has a function of receiving holes from the anode, the hole injection layer, or the hole transport layer and receiving electrons from the cathode, the electron injection layer, or the electron transport layer when an electric field is applied, and providing a place for recombination of holes and electrons to emit light. The light-emitting layer may be composed of only a light-emitting material or may be a mixed layer of a host material and a light-emitting material. The light-emitting material may be a fluorescent light-emitting material or a phosphorescent light-emitting material, and the dopant may be one kind or two or more kinds. The host material is preferably a charge transport material. The host material may be one kind or two or more kinds. For example, a configuration in which an electron-transporting host material and a hole-transporting host material are mixed can be mentioned. Further, a material that does not have charge transport properties and does not emit light may be included in the light-emitting layer. Also, the light-emitting layer may be one layer or two or more layers, and each layer may emit light in a different emission color.

[0110] Examples of the fluorescent light-emitting material include benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, condensed aromatic compounds, perinone derivatives, oxadiazole derivatives, oxazine derivatives, aldazine derivatives, pyraridine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styrylamine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidene compounds, metal complexes of 8-quinolinol derivatives and metal complexes of pyromethene derivatives, various metal complexes typified by them, polymer compounds such as polythiophene, polyphenylene, and polyphenylene vinylene, and compounds such as organic silane derivatives.

[0111] The phosphorescent material includes, for example, a complex containing a transition metal atom or a lanthanoid atom. Examples of the transition metal atom include ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, and platinum. Among these, rhenium, iridium, and platinum are preferable. Examples of the lanthanoid atom include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among these lanthanoid atoms, neodymium, europium, and gadolinium are preferable.

[0112] Examples of the ligand of the complex include ligands described in, for example, "Comprehensive Coodination Chemistry" written by G. Wilkinson et al., published by Pergamon Press in 1987, and "Photochemistry and Photophysics of Coodination Compound" written by H. Yersin, published by Springer-Verlag in 1987.

[0113] Examples of the host material contained in the light-emitting layer include those having a carbazole skeleton, those having a diarylamine skeleton, those having a pyridine skeleton, those having a pyrazine skeleton, those having a triazine skeleton, those having an arylsilane skeleton, and the materials exemplified in the sections of the hole injection layer, hole transport layer, electron injection layer, and electron transport layer described later.

[0114] The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. Specifically, the hole injection layer and the hole transport layer are preferably layers containing a carbazole derivative, a triazole derivative, an oxazole derivative, an oxadiazole derivative, an imidazole derivative, a polyarylalkane derivative, a pyrazoline derivative, a pyrazolone derivative, a phenylenediamine derivative, an arylamine derivative, an amino-substituted chalcone derivative, a styrylanthracene derivative, a fluorenone derivative, a hydrazone derivative, a stilbene derivative, a silazane derivative, an aromatic tertiary amine compound, a styrylamine compound, an aromatic dimethylidene compound, a porphyrin compound, an organosilane derivative, carbon, etc.

[0115] The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. Specifically, the electron injection layer and the electron transport layer are preferably layers containing a triazole derivative, an oxazole derivative, an oxadiazole derivative, an imidazole derivative, a fluorenone derivative, an anthraquinodimethane derivative, an anthrone derivative, a diphenylquinone derivative, a thiopyrandioxide derivative, a carbodiimide derivative, a fluorenylidenemethane derivative, a distyrylpyrazine derivative, an aromatic ring tetracarboxylic anhydride such as naphthalene and perylene, a phthalocyanine derivative, a metal complex of an 8-quinolinol derivative or a metal phthalocyanine, and various metal complexes typified by a metal complex having a benzoxazole or benzothiazole as a ligand, an organosilane derivative, etc.

[0116] The hole blocking layer is a layer having a function of preventing the holes transported from the anode side to the light-emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic compound layer adjacent to the light-emitting layer on the cathode side. Further, the electron transport layer and the electron injection layer may also serve as the hole blocking layer. Examples of the organic compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, etc. Furthermore, a layer having a function of preventing electrons transported from the cathode side to the light-emitting layer from passing through to the anode side can be provided at a position adjacent to the light-emitting layer on the anode side. The hole transport layer and the hole injection layer may also serve this function.

Example

[0117] Hereinafter, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass". The compounding amounts in the table are in parts by mass.

[0118] [Production Example 1] Into a 500 ml separable four-necked flask equipped with a stirring blade, a cooling tube, a nitrogen inlet tube, and a thermometer, 100 g (1 mol) of succinic anhydride, 74 g (1 mol) of n-butanol, and 1 g of dimethylbenzylamine as a catalyst were charged, and the mixture was heated in an oil bath under a nitrogen stream until the internal temperature reached 100°C and reacted for 4 hours to obtain succinic acid mono-n-butyl ester. Next, 150 g (1 mol) of glycidyl phenyl ether was added, and the internal temperature was heated to 120°C under a nitrogen stream and reacted for 12 hours to obtain an addition product. Next, 150 g (1 mol) of glycidyl phenyl ether was added, and the internal temperature was heated to 120°C under a nitrogen stream and held for 12 hours to obtain a glycidyl phenyl ether adduct of succinic acid mono-n-butyl ester, which is a component represented by the general formula A1. Here, R6 is an n-butyl group derived from n-butanol.

[0119] [Production Example 2] Into a 500 ml separable four-necked flask equipped with a stirring blade, a cooling tube, a nitrogen inlet tube, and a thermometer, 98 g (1 mol) of maleic anhydride, 144 g (1 mol) of 4-hydroxybutyl acrylate, and 1 g of dimethylbenzylamine as a catalyst were charged, and the mixture was heated in an oil bath under a nitrogen stream until the internal temperature reached 100°C and reacted for 4 hours to obtain succinic acid mono-4-acryloylbutyl ester. Next, 120 g (1 mol) of glycidyl acrylate and 0.12 g of methoxyhydroquinone as a polymerization inhibitor were added, and the internal temperature was heated to 110 °C under a stream of air and reacted for 12 hours to obtain a glycidyl phenyl ether adduct of succinic acid mono-4-acryloylbutyl, which is a component represented by the general formula A1. Here, R6 is a 4-acryloylbutyl group derived from 4-hydroxybutyl acrylate.

[0120] [Production Example 3] Into a 500 ml separable four-necked flask equipped with a stirring blade, a condenser, a nitrogen inlet tube, and a thermometer, 98 g (1 mol) of succinic anhydride, 144 g (1 mol) of 4-hydroxybutyl acrylate, and 1 g of dimethylbenzylamine as a catalyst were charged, and the mixture was heated in an oil bath under a stream of nitrogen until the internal temperature reached 100 °C and reacted for 4 hours to obtain succinic acid mono-4-acryloylbutyl ester. Next, 156 g (0.5 mol) of bisphenol A diglycidyl ether and 0.12 g of methoxyhydroquinone as a polymerization inhibitor were added, and the internal temperature was heated to 110 °C under a stream of air and held for 12 hours to obtain a bisphenol A diglycidyl phenyl ether adduct of succinic acid mono-4-acryloylbutyl, which is a component represented by the general formula A2. Here, R6 is a 4-acryloylbutyl group derived from 4-hydroxybutyl acrylate.

[0121] [Production Example 4] Into a 500 ml separable four-necked flask equipped with a stirring blade, a condenser, a nitrogen inlet tube, and a thermometer, 100 g (1 mol) of succinic anhydride, 130 g (1 mol) of 2-hydroxypropyl acrylate, and 1 g of dimethylbenzylamine as a catalyst were charged, and the mixture was heated in an oil bath under a stream of nitrogen until the internal temperature reached 100 °C and reacted for 4 hours to obtain succinic acid mono-1-methyl-2-acryloylethyl ester. Next, 156 g (0.5 mol) of bisphenol A diglycidyl ether and 0.12 g of methoxyhydroquinone as a polymerization inhibitor were added, and the internal temperature was heated to 120°C under a stream of air and reacted for 12 hours to obtain a bisphenol A diglycidyl phenyl ether adduct of succinic acid mono-1-methyl-2-acryloylethyl, which is a component represented by the general formula A2. Here, R6 is a 1-methyl-2-acryloylethyl group derived from 2-hydroxypropyl acrylate.

[0122] [Comparative Production Example 1] Into a 500 ml separable four-necked flask equipped with a stirring blade, a condenser, a nitrogen inlet tube, and a thermometer, 128 g (1 mol) of adipic anhydride (a monobasic acid dianhydride in which there are 6 carbon atoms between the carbon atoms of the two carbonyl groups and the two α-position carbon atoms are not bonded), 74 g (1 mol) of n-butanol, and 1 g of dimethylbenzylamine as a catalyst were charged, and the mixture was heated in an oil bath under a stream of nitrogen until the internal temperature reached 100°C and reacted for 4 hours to obtain adipic acid mono-n-butyl ester. Next, 150 g (1 mol) of glycidyl phenyl ether was added, and the internal temperature was heated to 120°C under a stream of nitrogen and reacted for 12 hours to obtain an addition product.

[0123] [Comparative Production Example 2] Into a 500 ml separable four-necked flask equipped with a stirring blade, a condenser, a gas inlet tube, and a thermometer, 128 g (1 mol) of adipic anhydride, 130 g (1 mol) of hydroxypropyl acrylate, 1 g of dimethylbenzylamine as a catalyst, and 0.12 g of methoxyhydroquinone as a polymerization inhibitor were charged, and the mixture was heated in an oil bath under a stream of air until the internal temperature reached 100°C and reacted for 4 hours to obtain adipic acid monoacryloyloxypropyl butyl ester. Next, 85 g of bisphenol A diglycidyl ether was added, and the internal temperature was heated to 110°C under a stream of air and reacted for 12 hours to obtain an addition product.

[0124] [Comparative Production Example 3] Into a 500 ml separable four-necked flask equipped with a stirring blade, a cooling pipe, a gas introduction pipe, and a thermometer, 87 g (0.5 mol) of suberic acid (alias: octanedioic acid), 128 g (1 mol) of glycidyl acrylate, 1 g of dimethylbenzylamine as a catalyst, and 0.12 g of methoxyhydroquinone as a polymerization inhibitor were added, and the reaction was carried out at 110 °C for 12 hours under a stream of air to obtain an addition product.

[0125] <Example 1> As component (A), 5 parts of a glycidyl phenyl ether adduct of succinic acid mono-n-butyl ester obtained in Production Example 1; as component (B), 10 parts of α-allyloxymethyl acrylate (AOMA, manufactured by Nippon Shokubai), 55 parts of dipropylene glycol diacrylate (M222, manufactured by MIWON), 30 parts of trimethylolpropane trimethacrylate (hereinafter, TMPTA, manufactured by Nippon Shokubai), 5 parts of Lucirin TPO (photoinitiator, manufactured by BASF Japan), 0.5 part of BYK3500 (surface conditioner, manufactured by BYK Chemie), and 0.05 part of Poly Stop 7300P (polymerization inhibitor, manufactured by Hakuto Co., Ltd.) were mixed to obtain a radiation-curable inkjet ink.

[0126] After filtering this photocurable composition through a 1 μm disk filter, it was filled into a 10 pl cartridge (DMC-11610) for an inkjet printer DMP2850 manufactured by Dimatix. Next, a hole injection electrode made of indium-tin oxide (hereinafter, ITO) was formed on a polyethylene terephthalate (hereinafter, PET) film provided with a barrier layer made of silicon nitride, which serves as the anode of the organic EL light-emitting element. After pattern printing was performed on the barrier layer and the ITO electrode using DMP2850, the coated film was transferred to a nitrogen-flow conveyor with an oxygen concentration controlled to 300 ppm or less, and the center was irradiated with ultraviolet light from an LED light source with a wavelength exceeding 395 nm at an integrated light quantity of 500 mJ / cm2 (measured in the UVA range) to obtain a PET film with an ITO electrode on which an insulating layer was pattern printed. Further, a hole transport layer (thickness: 50 nm) made of N,N'-di-1-naphthyl-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPD) was formed on this film. On the hole transport layer, a light-emitting layer (thickness: 50 nm) made of 99.5 mol% of 4-phenylbenzophenone (4PBP) as a host material and 0.5 mol% of rubrene (5,6,11,12-tetraphenylnaphthacene) as a luminescent dopant was formed. Further, an electron transport layer (thickness: 15 nm) made of Alq3 (tris(8-hydroxyquinoline)aluminum) and an electron injection electrode were sequentially formed on the light-emitting layer to fabricate an organic EL element. The electron injection electrode was formed by sequentially laminating a LiF layer (thickness: 0.5 nm) and an aluminum layer (thickness: 80 nm) to form an organic EL element. In addition, each layer constituting the organic EL element was deposited by a resistance heating type vacuum evaporation method at a pressure of 1.3×10 -4 Pa (1×10 -6 Torr).

[0127] Next, a first barrier layer made of silicon nitride was provided on the electron injection electrode in the organic EL element by sputtering. The radiation-curable inkjet ink of each example was coated on the first barrier layer and photocured to form an organic protective layer. A second barrier layer made of silicon nitride was provided on the organic protective layer to prepare a light-emitting body sample for a light-emitting test.

[0128] <Example 2> As component (A), except that it was an addition product of the succinic acid mono-4-acryloylbutyl ester obtained in Production Example 2 and glycidyl acrylate, it was blended at the same ratio as in Example 1 to prepare a photocurable composition. Further, in the same manner as in Example 1, IJ printing was performed on an ITO electrode film, and each layer necessary for LED curing and OLED light emission was laminated to prepare a light-emitting sample for a light-emitting test.

[0129] <Example 3> As component (A), except that it was an addition product of the succinic acid mono-4-acryloylbutyl ester obtained in Production Example 3 and bisphenol A diglycidyl ether, it was blended at the same ratio as in Example 1 to obtain a photocurable composition. Further, in the same manner as in Example 1, IJ printing was performed on an ITO electrode film, and each layer necessary for LED curing and OLED light emission was laminated to prepare a light-emitting sample for a light-emitting test.

[0130] <Example 4> As component (A), except that it was an addition product of the succinic acid mono-acryloylpropyl ester obtained in Production Example 4 and bisphenol A diglycidyl ether, it was blended at the same ratio as in Example 1 to obtain a photocurable composition. Further, in the same manner as in Example 1, IJ printing was performed on an ITO electrode film, and each layer necessary for LED curing and OLED light emission was laminated to prepare a light-emitting sample for a light-emitting test.

[0131] <Comparative Example 1> As component (A), except that it was an adduct of the adipic acid mono-n-butyl ester obtained in Comparative Production Example 1 and glycidyl phenyl ether, it was blended at the same ratio as in Example 1 to obtain a photocurable composition. Further, in the same manner as in Example 1, IJ printing was performed on an ITO electrode film, and each layer necessary for LED curing and OLED light emission was laminated to prepare a light-emitting sample for a light-emitting test.

[0132] <Comparative Example 2> As component (A), a photocurable composition was obtained by blending in the same ratio as in Example 1, except that an adduct of monoacryloyloxypropyl butyl adipate and bisphenol A diglycidyl ether obtained in Comparative Production Example 2 was used. Furthermore, in the same manner as in Example 1, IJ printing was performed on an ITO electrode film, and each layer necessary for LED curing and OLED light emission was laminated to prepare a light-emitting sample for a light-emitting test.

[0133] <Comparative Example 3> As component (A), a photocurable composition was obtained by blending in the same ratio as in Example 1, except that 3-acryloyl-2-hydroxypropyl suberate obtained in Comparative Production Example 3 was used. Furthermore, in the same manner as in Example 1, IJ printing was performed on an ITO electrode film, and each layer necessary for LED curing and OLED light emission was laminated to prepare a light-emitting sample for a light-emitting test.

[0134] <Evaluation of Adhesion> The adhesion of the planarization layer to the substrate surface of the insulating layer-attached film obtained by coating and curing the photocurable composition on the substrate film on which the barrier layers and ITO electrodes of Examples 1 to 6 and Comparative Examples 1 to 3 were formed was evaluated according to the following criteria by the cross-cut cellophane tape peeling method. ◎: 100% adhered 〇: 80% or more adhered △: 40% or more adhered ×: 40% or less adhered

[0135] <Evaluation of Light-Emitting Test> For the prepared light-emitting sample, a light-emitting test was performed by applying a positive voltage to the hole injection electrode and a negative voltage to the electron injection electrode. The results of observing the overall light-emitting state, particularly the light-emitting state at the end of the insulating layer printed by IJ, were evaluated. Furthermore, continuous lighting was performed at room temperature, and the monitoring results of the light-emitting state after 100 hours were evaluated.

[0136]

Table 1

Description of Symbols

[0137] 1 ····· Substrate 2 ····· Barrier layer 3 ····· Lower electrode 4 ····· Insulating layer 5 ····· Organic multilayer part including a light-emitting layer 6 ····· Counter electrode 7 ····· Light-emitting element part

Claims

1. A radiation-curable inkjet ink for forming an insulating layer of an organic EL element having an organic light-emitting layer and an insulating layer between a pair of electrodes composed of a lower electrode and a counter electrode, The radiation-curable inkjet ink contains a component (A), a (meth)acrylate component (B) having a (meth)acrylate group, and a photopolymerization initiator, The radiation-curable inkjet ink, wherein the component (A) is any one represented by the following general formula A1 or A2. 【Chemical Formula 1】 R 101 : The remaining part obtained by removing the glycidyl ether group from a compound having one glycidyl ether group, and the compound having one glycidyl ether group is glycidyl phenyl ether or a glycidyl ether having a (meth)acryloyl group. R 2 、R 3 、R 4 、R 5 : The remaining part obtained by removing the anhydride group and two α-position carbons from a dibasic acid monoanhydride, and the dibasic acid monoanhydride is succinic anhydride. R 6 : An alkyl group or a group represented by the following general formula (1). 【Chemical Formula 2】 R 102 : The remaining part obtained by removing two glycidyl ether groups from a compound having two glycidyl ether groups, and the compound having two glycidyl ether groups is a bisphenol type epoxy compound. R 2 、R 3 、R 4 、R 5 : The remaining part obtained by removing the anhydride group and two α-position carbons from a dibasic acid monoanhydride, and the dibasic acid monoanhydride is succinic anhydride. R 6' : A group represented by the following general formula (1). R7: An alkylene group having no substituent. m 1 、m 2is 0. 【Chemical Formula 8】 R 7 : An alkylene group having no substituent. R 9 : Hydrogen. * represents a bonding site.

2. The radiation-curable inkjet ink according to claim 1, wherein the component (A) is a glycidyl phenyl ether adduct of succinic acid mono-n-butyl ester, a glycidyl phenyl ether adduct of succinic acid mono-4-acryloylbutyl, a bisphenol A diglycidyl phenyl ether adduct of succinic acid mono-4-acryloylbutyl, or a bisphenol A diglycidyl phenyl ether adduct of succinic acid mono-1-methyl-2-acryloylethyl.

3. An organic EL element having an organic light-emitting layer and an insulating layer between a pair of electrodes composed of a lower electrode and a counter electrode, wherein the insulating layer is formed of a radiation-curable inkjet ink, and the radiation-curable inkjet ink contains the radiation-curable inkjet ink according to claim 1 or 2.

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