JP2020030290A - Curable composition, cured film, display element, and cured film forming method - Google Patents

Abstract

To provide a curable composition which improves storage stability and radiosensitivity and can form a cured film with high hardness and excellent solvent resistance even through a curing firing process at or below 200°C.SOLUTION: A curable composition contains (A) a compound with a polymerizable group, (B) a photosensitizer, and (C) a thermally activated delayed fluorescence compound, which is a compound represented by the general formula (1) or (2).SELECTED DRAWING: None

Description

  The present invention relates to a curable composition, a display element, and a method for forming a cured film.

  For display devices such as liquid crystal display devices, organic electroluminescence devices (organic EL devices), and electronic paper devices, protective films for preventing deterioration and damage of electronic components such as touch panels, between wirings arranged in layers. There is provided a cured film such as an interlayer insulating film for maintaining the insulating property and a flattening film for increasing the aperture ratio. For the formation of such a cured film, a radiation-sensitive curable composition is used.For example, a coating film of the curable composition is formed on a substrate and exposed through a photomask having a predetermined pattern. Then, development is performed with a developer to remove unnecessary portions, and then heating (post-baking) is performed to obtain a cured film.

  The curable composition is required to have a viscosity that does not become excessively high even after storage for a long period of time (storage stability) and to have good radiation sensitivity. Further, the cured film obtained from the curable composition is required to have high hardness and excellent resistance to a solvent (solvent resistance) used in a step after the formation of the cured film.

  In addition, in the formation of such a cured film, the curing and baking process is usually performed at 200 ° C. or higher. (JP-A-2013-237750, JP-A-2013-237750).

  However, with the curable composition described in the above publication, it has been difficult to form a cured film having high hardness and excellent solvent resistance even in a low-temperature baking process while improving storage stability and radiation sensitivity.

JP 2017-12068 A JP 2011-2557537 A

  The present invention has been made based on the above-described circumstances, and the object is to improve the storage stability and radiation sensitivity, and to improve the storage stability and radiation sensitivity of a film obtained by a curing and firing process at 200 ° C. or lower. It is an object of the present invention to provide a curable composition capable of forming a cured film having high solvent resistance, a cured film obtained from the curable composition, a display element using the cured film, and a method for forming the cured film. .

The present inventors have conducted intensive studies in order to solve the above problems. As a result, they have found that the above problems can be solved by a curable composition having the following constitution, and have completed the present invention.

The invention made to solve the above-mentioned problem is:
(1) A curable composition containing [A] a compound having a polymerizable group, [B] a photosensitizer, and [C] a thermally activated delayed fluorescent compound.

  (2) The curable composition wherein the (C) thermally activated delayed fluorescent compound is a compound represented by the following formula (1).

In the formulas (1) and (2), at least one of R ¹ to R ⁷ is a hydrogen atom, an alkyl having 1 to 12 carbons, a phenyl group, a tolyl group, a naphthyl group, a cyano group, or a group represented by the formula (X). Represents a group to be formed.
In the formula (X), R ²¹ to R ²⁸ each independently represent a hydrogen atom or a substituent. However, <A> which satisfies at least one of <A> and <B> is R ²⁵ and R ²⁶ together form a single bond.
<B> R ²⁷ and R ²⁸ together form a substituted or unsubstituted benzene ring. )
(3) The above formula (X) is a 9-carbazolyl group, a 3,6-di (t-butyl) -9-carbazolyl group, a substituted or unsubstituted 1,2,3,4-tetrahydro-9-carbazolyl group , A substituted or unsubstituted 1-indolyl group, or a substituted or unsubstituted diarylamino group.
(4) The curable composition wherein the polymerizable group of the compound having a polymerizable group (A) is at least one selected from an epoxy group, a vinyl group, and a (meth) acryloyl group.
(5) The curable composition further contains (D) a binder resin.
(6) The (B) photosensitive composition is a curable composition selected from an acid generator, a base generator, and a radical polymerization initiator.
(7) The curable composition wherein the photosensitizer is a radical polymerization initiator containing a condensed ring.
(8) The curable composition wherein the content ratio of the (C) heat-activated delayed fluorescent compound to the total content of the (B) photosensitive agent is in the range of 0.1 to 3.
(9) A method of forming a cured film including the following steps: a step of forming a coating film of the curable composition on a substrate; a step of exposing the coating film or heating the coating film at a temperature of 80 ° C. or more and 150 ° C. or less (10) Display element having cured film obtained by film forming method

Hereinafter, embodiments of the present invention will be described in detail, but are not limited thereto.
<Curable composition>
The curable composition of the present invention is a curable composition containing (A) a compound having a polymerizable group, (B) a photosensitizer, and (C) a thermally activated delayed fluorescent compound.

The curable composition contains [A] a compound having a polymerizable group, [B] a photosensitizer, and [C] a thermally activated delayed fluorescent compound, thereby improving the storage stability and radiation sensitivity while maintaining low temperature. The cured film formed by the firing process has a high hardness and can form a cured film having excellent solvent resistance.
Thermally activated delayed fluorescence (TADF) is a phenomenon that emits light through conversion of triplet excitons to singlet excitons, which does not normally occur, and is activated by heat and usually Shows a longer fluorescence lifetime than that of the fluorescent material. It is attracting attention as a next-generation organic EL light emitting material that can improve light conversion efficiency. In the present invention, it has been found that a curing reaction proceeds in a temperature range in which TADF is generated and a cured film is formed by using the compound causing TADF in combination with a photosensitizer having a similar structure.
In the formation of a normal cured film, a coating film is formed with a curable composition, and a photosensitizer is exposed to light to generate a polymerization initiator species by exposure, and a cross-linking reaction of a compound having a polymerizable group is performed. Start to form a cured film. Furthermore, in a usual curing process, the crosslinked structure formed is heated to 200 ° C. or higher in order to make the crosslinked structure stronger. Usually, a cured film is formed by light curing and heat curing.
However, in the present invention, a curing reaction is performed using the TADF effect instead of the high-temperature heating and firing process at 200 ° C. or higher. A combination of photosensitizers having a similar energy order in the singlet excited state that causes a TADF effect at a temperature higher than room temperature (50 to 100 ° C.) is used.
It is considered that electron transfer occurs from the material in which the TADF effect occurs to the photosensitizer, and the photosensitizer is excited to generate a polymerization initiator species, and the curing reaction proceeds again by the generation of the polymerization initiator species. Thus, it is presumed that a cured film can be formed without using a high-temperature process by using (C) the thermally activated delayed fluorescent compound.

First, the compound [A] having a polymerizable group contained in the curable composition of the present invention is invented.
<[A] Compound having a polymerizable group>
The compound [A] having a polymerizable group in the present invention is a compound having one or more polymerizable groups in one molecule, and the polymerizable group is selected from an epoxy group, a vinyl group, and a (meth) acryloyl group. At least one. [A] The compound having a polymerizable group may be a monomer compound or a polymer.

  [A] The polymerizable group of the monomer compound having a polymerizable group is preferably a polymerizable compound having a (meth) acryloyl group or a vinyl group from the viewpoint of radical polymerizability. By containing these compounds, it is possible to increase the hardness of the obtained cured film, and it is possible to improve the adhesion of the cured film to the substrate.

Specific examples of such compounds include the following compounds.
For example, monofunctional, difunctional, or trifunctional or higher (meth) acrylic acid esters are preferable from the viewpoint of increasing the polymerizability and the strength of the formed cured film. Further, it is also possible to use a vinyl sulfide derivative, a (meth) acrylate derivative, a vinyl sulfoxide derivative or a vinyl sulfone derivative having a vinyl group. These compounds are preferred in that they can improve sensitivity and maintain good storage stability of the curable composition.

  Examples of the monofunctional (meth) acrylate include 2-hydroxyethyl (meth) acrylate, diethylene glycol monoethyl ether (meth) acrylate, (2- (meth) acryloyloxyethyl) (2-hydroxypropyl) phthalate, ω-carboxypolycaprolactone mono (meth) acrylate and the like. As these commercially available products, for example, Aronix (registered trademark) M-101, M-111, M-114, and M-5300 (all manufactured by Toagosei Co., Ltd.); (Trademark) TC-110S and TC-120S (all manufactured by Nippon Kayaku Co., Ltd.); and Viscort 158 and 2311 (all manufactured by Osaka Organic Chemical Industry Co., Ltd.).

  Examples of the bifunctional (meth) acrylate include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol diacrylate, and tetraethylene glycol di (meth) acrylate. Examples thereof include acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, and fluorene diacrylate. As these commercially available products, for example, Aronix (registered trademark) M-210, M-240, and M-6200 (all manufactured by Toagosei Co., Ltd.), KAYARAD (registered trademark) HDDA, HX-220, R-604 (all manufactured by Nippon Kayaku Co., Ltd.), VISCOAT 260, 312, and 335HP (all manufactured by Osaka Organic Chemical Industry Co., Ltd.), Light Acrylate 1,9-NDA (Kyoeisha) OGSOL (EA-0200 manufactured by Osaka Gas Chemical Co., Ltd.) and the like can be mentioned.

Examples of the trifunctional or higher functional (meth) acrylic acid ester include, for example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Dipentaerythritol hexa (meth) acrylate;
A mixture of dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate;
Ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, tri (2- (meth) acryloyloxyethyl) phosphate, succinic acid-modified pentaerythritol tri (meth) acrylate, succinic acid-modified dipentaerythritol penta (meth) acrylate, tri A mixture of pentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate, isocyanuric acid EO-modified diacrylate and isocyanuric acid EO-modified triacrylate;
A compound having a linear alkylene group and an alicyclic structure and having two or more isocyanate groups, and having three, four, or five (meth) acryloyloxy groups having one or more hydroxyl groups in the molecule; And a polyfunctional urethane acrylate-based compound obtained by reacting a compound having a group.

  Commercial products of the above-mentioned trifunctional or higher functional (meth) acrylic acid esters include, for example, Aronix (registered trademark) M-309, M-400, M-405, M-450, and M -7100, M-8030, M-8060, TO-1450 (manufactured by Toagosei Co., Ltd.), KAYARAD (registered trademark) TMPTA, DPHA, DPCA-20, DPCA-30, DPCA -60, DPCA-120, DPEA-12 (Nippon Kayaku Co., Ltd.), VISCOAT 295, 300, 360, GPT, 3PA, 400 (all, Osaka Organic Chemical Industry Co., Ltd.) )) And commercially available products containing a polyfunctional urethane acrylate-based compound, such as New Frontier (registered trademark) R-1150 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and KAYARAD ( Recording trademark) DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.), and the like.

Among these, ω-carboxypolycaprolactone monoacrylate, 1,9-nonanediol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate ;
A mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate;
A mixture of tripentaerythritol hepta (meth) acrylate and tripentaerythritol octa (meth) acrylate;
Commercial products containing ethylene oxide-modified dipentaerythritol hexaacrylate, polyfunctional urethane acrylate compounds, succinic acid-modified pentaerythritol triacrylate, and succinic acid-modified dipentaerythritol pentaacrylate are preferred.
Examples of the compound having a vinyl group include styrene, vinylnaphthalene, 1,3-divinylnaphthalene, 1,4-divinylnaphthalene, 1,5-divinylnaphthalene, 1,6-divinylnaphthalene, 1,7-divinylnaphthalene, 2, 3-divinylnaphthalene, 2,6-divinylnaphthalene, 2,7-divinylnaphthalene, 1,2,4-trivinylnaphthalene, 1,2,6-trivinylnaphthalene, 1,3,6-trivinylnaphthalene, 1,3-divinyl-6-methoxy-naphthalene, 1,3-divinyl-6-methyl-naphthalene, 1,3-divinyl-6-chloro-naphthalene, 1,2-divinyl-6-ethoxy-naphthalene, 1-vinyl -5-methoxy-naphthalene, 1-vinylnaphthalene, 2-vinylnaphthalene and the like.

  It is also possible to use a vinyl sulfide derivative, a (meth) acrylate derivative, a vinyl sulfoxide derivative or a vinyl sulfone derivative having a vinyl group. Specific examples of such compounds include vinyl sulfide, phenyl vinyl sulfoxide, divinyl sulfoxide, divinyl sulfone, phenyl vinyl sulfone, and bis (vinyl sulfonyl) methane.

The above monomer compounds can be used alone or in combination of two or more. The ratio of the monomer compound used in the curable composition of the present invention is not particularly limited as the lower limit of the monomer compound, but is, for example, 50% by mass in terms of solid content, and preferably 60% by mass. On the other hand, the upper limit is preferably 99% by mass, and more preferably 95% by mass.
[A] When the compound having a polymerizable group is a polymer, a polymer having a structural unit having a (meth) acryloyloxy group in the polymer can be used (hereinafter, also referred to as [a] polymer). ). Such a polymer can be used in combination with a monomer compound, and in this case, the polymer can also be used as a binder resin.

  The structural unit having a (meth) acryloyloxy group is, for example, a method of reacting a (meth) acrylic acid with an epoxy group in a polymer, or a method of reacting a (meth) acrylate having an epoxy group with a carboxyl group in a polymer. It can be formed by a method of reacting a (meth) acrylic acid ester having an isocyanate group with a hydroxyl group in a polymer, a method of reacting (meth) acrylic acid with an acid anhydride site in a polymer, or the like.

[A] The polymer is obtained, for example, by copolymerizing a compound (a1) that provides a carboxyl group-containing structural unit with a compound that provides another structural unit in a solvent in the presence of a polymerization initiator. It can be produced by reacting the (a2) compound which gives the (meth) acryloyl group-containing structural unit to the carboxyl group-containing structural unit.
[(A1) compound]
Examples of the (a1) compound include unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, anhydrides of unsaturated dicarboxylic acids, and mono [(meth) acryloyloxyalkyl] esters of polycarboxylic acids. Examples of the unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, crotonic acid and the like. Examples of the unsaturated dicarboxylic acid include maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid. Examples of the anhydride of the unsaturated dicarboxylic acid include anhydrides of the compounds exemplified as the above dicarboxylic acid. Examples of the mono [(meth) acryloyloxyalkyl] ester of polycarboxylic acid include mono [2- (meth) acryloyloxyethyl] succinate, mono [2- (meth) acryloyloxyethyl] phthalate and the like. Can be

  Among these (a1) compounds, acrylic acid, methacrylic acid, and maleic anhydride are preferable, and acrylic acid, methacrylic acid, and maleic anhydride are more preferable in view of copolymerization reactivity, solubility in an aqueous alkali solution, and easy availability. These (a1) compounds may be used alone or as a mixture of two or more.

(A1) The use ratio of the compound is preferably 5% by mass to 30% by mass, more preferably 10% by mass to 25% by mass, based on the total amount of the constituent monomers of the polymer (a). By setting the use ratio of the (a1) compound to 5% by mass to 30% by mass, the solubility of the polymer in an aqueous alkaline solution can be optimized.
The (meth) acrylic acid ester having an epoxy group is an unsaturated compound containing an epoxy group. Examples of the epoxy group include an oxiranyl group (1,2-epoxy structure) and an oxetanyl group (1,3-epoxy structure). . Specifically, glycidyl (meth) acrylate, 3- (meth) acryloyloxymethyl-3-ethyloxetane, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxytricyclo [5.2. 1.0 ^2.6 ] decyl (meth) acrylate, tris (4-hydroxyphenyl) ethane triglycidyl ether and the like.

The polymer of the present embodiment can be produced by a known method. Examples of the polymer include, for example, JP-A-2003-222717, JP-A-2006-259680, WO07 / 029871, and JP-A-5-298681. 19467, JP-A-6-230212, JP-A-7-207211, JP-A-09-325494, JP-A-11-140144, JP-A-2008-181095, etc. Can be synthesized by
[A] The structural unit having a (meth) acryloyloxy group of the polymer is obtained by reacting a (meth) acrylic ester having an epoxy group with a carboxyl group in the copolymer, and the (meth) acrylic acid after the reaction is obtained. The structural unit having a group is represented by the following formula (3a).

In the above formula (3a), R ³⁰ and R ³¹ are each independently a hydrogen atom or a methyl group. a is an integer of 1 to 6. R ³² is a divalent group represented by the following formula (3a-1) or (3a-2).

In the above formula (3a-1), R ³³ is a hydrogen atom or a methyl group. In the above formulas (3a-1) and (3a-2), * indicates a site bonded to an oxygen atom. For the structural unit represented by the above formula (3a), for example, when a compound such as glycidyl methacrylate or 2-methylglycidyl methacrylate is reacted with a copolymer having a carboxyl group, R in the formula (3a) ²² is given by equation (3a-1). On the other hand, is formed by reaction with compounds such as methacrylic acid 3,4-epoxycyclohexylmethyl, ^{R 32} in the formula (3a) is a formula (3a-2).

The weight average molecular weight (Mw) of the polymer [a] is usually from 1,000 to 100,000, preferably from 3,000 to 50,000. Mw refers to polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (elution solvent: tetrahydrofuran).
[A] As the polymer, the resin having an ethylenically unsaturated group and a carboxyl group is more preferably a resin having a structural site represented by the following formula (3b). By having an ethylenically unsaturated group and a carboxyl group, the polymerizability of the ethylenically unsaturated group and the carboxyl group and alkali developability can both be achieved at a high level, making it possible to achieve both sensitivity and developability at a high level. Become.

(In the formula (3b), R ⁴⁰ represents a divalent hydrocarbon group, R ⁴¹ represents a hydrogen atom or a methyl group, and * represents a bonding position.)
Specific examples of the resin having an ethylenically unsaturated group and a carboxyl group having a structural site represented by the above formula (3b) are shown below.

As the resin having a structural site represented by the formula (3b), an acid-modified epoxy (meth) acrylate resin is preferably used. Acid-modified cresol novolak epoxy (meth) acrylate resin, phenol novolak epoxy (meth) acrylate resin, bisphenol A epoxy (meth) acrylate resin, bisphenol F epoxy (meth) acrylate resin, biphenyl epoxy (meth) A) acrylate resins and trisphenolmethane-type epoxy (meth) acrylate resins.
Examples of the acid-modified cresol novolak type epoxy (meth) acrylate resin include a polymer represented by the following formula (1). The acid-modified cresol novolak-type epoxy (meth) acrylate resin is, for example, an epoxy (meth) acrylate resin obtained by reacting (meth) acrylic acid with a cresol novolak-type epoxy resin, and an anhydride for alkali solubility. It is obtained by reacting an acid anhydride such as phthalic acid, 1,2,3,6-tetrahydrophthalic anhydride.

  The acid-modified cresol novolak epoxy (meth) acrylate resin has a rigid main chain skeleton of the cresol novolak epoxy resin, an ethylenically unsaturated group, and a carboxy group, so that it can be cured and fired at low temperatures. Regardless, it is possible to form a cured film having excellent film hardness, excellent solvent resistance and excellent heat resistance.

  In the formula (3c), b and c each independently represent an integer of 1 to 30.

  Specific examples of the acid-modified cresol novolak epoxy (meth) acrylate resin include CCR-1171H, CCR-1291H, CCR-1307H, and CCR-1309H (manufactured by Nippon Kayaku Co., Ltd.).

  [A] The acid value of the polymer is, for example, 10 to 200 mgKOH / g, preferably 30 to 270 mgKOH / g, and more preferably 50 to 250 mgKOH / g. The acid value indicates the number of mg of KOH required to neutralize 1 g of the solid content of the alkali-soluble resin.

  [A] The weight average molecular weight (Mw) of the polymer is generally 1,000 to 100,000, preferably 3,000 to 50,000. Mw refers to polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (elution solvent: tetrahydrofuran).

  A polymer having an epoxy group as a polymerizable group can also be used. Such a polymer [a] can be obtained by radical polymerization using an epoxy group-containing unsaturated compound as a monomer together with other monomers such as methacrylic acid and acrylic acid. Examples of the epoxy group-containing unsaturated compound include unsaturated compounds containing an oxiranyl group (1,2-epoxy structure), an oxetanyl group (1,3-epoxy structure), and the like.

  Examples of the unsaturated compound having an oxiranyl group include glycidyl acrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate, and 6,7 acrylate. -Epoxyheptyl, 6,7-epoxyheptyl methacrylate, 6,7-epoxyheptyl α-ethylacrylate, 3,4-epoxycyclohexyl methacrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether And p-vinylbenzyl glycidyl ether.

  Examples of the unsaturated compound having an oxetanyl group include 3- (methacryloyloxymethyl) oxetane, 3- (methacryloyloxymethyl) -2-methyloxetane, 3- (methacryloyloxymethyl) -3-ethyloxetane, and 3- ( (Methacryloyloxymethyl) -2-phenyloxetane, 3- (2-methacryloyloxyethyl) oxetane, 3- (2-methacryloyloxyethyl) -2-ethyloxetane, 3- (2-methacryloyloxyethyl) -3-ethyloxetane And methacrylic acid esters such as 3- (2-methacryloyloxyethyl) -2-phenyloxetane and 3- (2-methacryloyloxyethyl) -2,2-difluorooxetane.

  Of these epoxy group-containing unsaturated compounds, glycidyl methacrylate, 3,4-epoxycyclohexyl methacrylate, and 3- (methacryloyloxymethyl) -3-ethyloxetane are preferred from the viewpoint of polymerizability.

  The content of the polymer [a] in the radiation-sensitive resin composition is usually 30% by mass or more, preferably 40% by mass or more, based on 100% by mass of the solid content of the composition, and the content of the polymer [a] The upper limit of the content is usually 90% by mass in 100% by mass of the solid content of the composition, and in one embodiment, is 70% by mass or 60% by mass.

By adopting such an embodiment, in addition to further improving luminance, alkali developability, storage stability of the composition, pattern shape, and chromaticity characteristics can be improved. The solid content is all components other than the solvent.
<[B] Photosensitizer>
The curable composition contains [B] a photosensitive agent. The radiation sensitivity of the curable composition can be further increased. [B] The photosensitive agent may be used alone or in combination of two or more.

  [B] Examples of the photosensitive agent include a radiation-sensitive radical polymerization initiator, a radiation-sensitive acid generator, a radiation-sensitive base generator, and a combination thereof.

  When the compound having a polymerizable group [A] has an ethylenically unsaturated group such as a (meth) acryloyl group or a vinyl group, the radiation-sensitive radical polymerization initiator may be used in the curable composition. Curing reaction can be accelerated.

  Examples of the radiation-sensitive radical polymerization initiator include: [A] an activity capable of initiating a radical polymerization reaction of a compound having a polymerizable group by exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, an electron beam, and X-rays. Examples include compounds capable of generating seeds.

  Specific examples of the radiation-sensitive radical polymerization initiator include, for example, O-acyl oxime compounds, α-aminoketone compounds, α-hydroxyketone compounds, acylphosphine oxide compounds, and the like.

  Examples of the O-acyl oxime compound include 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-acetate, 1- [9-ethyl-6-benzoyl-9. H. -Carbazol-3-yl] -octane-1-one oxime-O-acetate, 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-oneoxime-O-benzoate, 1- [9-n-butyl-6- (2-ethylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-benzoate, ethanone, 1- [9-ethyl-6- (2-methyl-4-tetrahydrofuranylbenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime), ethanone, 1- [9-ethyl-6- (2-methyl-4-tetrahydropyranylbenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime), ethanone, 1- [9-ethyl-6- (2-methyl-5-tetrahydrofuranylbenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime), ethanone, 1- [9-ethyl-6- {2-methyl-4- (2,2-dimethyl-1,3-dioxolanyl) methoxy] Benzoyl II-9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime), ethanone, 1- [9-ethyl-6- (2-methyl-4-tetrahydrofuranylmethoxybenzoyl) -9. H. -Carbazol-3-yl]-, 1- (O-acetyloxime), 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)] and the like.

  Examples of the α-aminoketone compound include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one and 2-dimethylamino-2- (4-methylbenzyl) -1- ( 4-morpholin-4-yl-phenyl) -butan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one and the like.

  Examples of the α-hydroxyketone compound include 1-phenyl-2-hydroxy-2-methylpropan-1-one and 1- (4-i-propylphenyl) -2-hydroxy-2-methylpropan-1-one. , 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone, and the like.

  Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.

  As the radiation-sensitive radical polymerization initiator, a radical polymerization initiator containing a condensed ring is preferable from the viewpoint of strengthening the interaction with TADF and further promoting the curing reaction by radiation. Specific examples of the condensed ring include naphthalene, anthracene, fluorene, indole, carbazole, benzimidazole and the like. Of these, carbazole-derived carbazolyl groups and substituted or unsubstituted 1,2,3,4-tetrahydro-9-carbazolyl groups are particularly preferred. As the radical polymerization initiator containing such a condensed ring, an O-acyl oxime compound and an α-aminoketone compound are preferable, and 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-acetate is preferred.

  In the case where the curable composition contains a radiation-sensitive radical polymerization initiator, the lower limit of the content of the radiation-sensitive radical polymerization initiator is set to 0.A with respect to 100 parts by mass of the compound having a polymerizable group. It is preferably 5 parts by mass, more preferably 1.0 part by mass, and still more preferably 1.5 parts by mass. In addition, the upper limit of the content is preferably 20 parts by mass, more preferably 15 parts by mass, and still more preferably 10 parts by mass with respect to 100 parts by mass of the compound having a polymerizable group [A]. By setting the content to the above range, the curing reaction by radiation can be further promoted.

  Specific examples of the radiation-sensitive acid generator include, for example, iodonium salt-based radiation-sensitive acid generator, sulfonium salt-based radiation-sensitive acid generator, tetrahydrothiophenium salt-based radiation-sensitive acid generator, imide sulfonate-based Examples include a radiation-sensitive acid generator, an oxime sulfonate-based radiation-sensitive acid generator, and a quinonediazide compound.

  Examples of the iodonium salt-based radiation-sensitive acid generator include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium pyrene sulfonate, diphenyliodonium dodecylbenzenesulfonate, diphenyliodonium nonafluoro n-butanesulfonate, and bis (4-t-butylphenyl) iodonium Trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium dodecylbenzenesulfonate, and the like.

  Examples of the sulfonium salt-based radiation-sensitive acid generator include, for example, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalene sulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, (hydroxyphenyl) Benzenemethylsulfonium toluenesulfonate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, dicyclohexyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, dimethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, triphenylsulfonium camphorsulfonate, ( 4-hydroxy Phenyl) benzyl methyl sulfonium toluene sulfonate, 1-naphthyl dimethyl sulfonium trifluoromethane sulfonate, 1-naphthyl diethyl sulfonium trifluoromethane sulfonate, 4-hydroxy-1-naphthyl dimethyl sulfonium trifluoromethane sulfonate and the like.

  Examples of the tetrahydrothiophenium salt-based radiation-sensitive acid generator include 4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-methoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, and 4-ethoxy. -1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-methoxymethoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-ethoxymethoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4- (1-methoxy Ethoxy) -1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4- (2-methoxyethoxy) -1-naphthyltetrahydrothiof Trifluoromethanesulfonate, and the like.

  Examples of the imide sulfonate-based radiation-sensitive acid generator include, for example, trifluoromethylsulfonyloxybicyclo [2.2.1] hept-5-enedicarboximide, succinimidetrifluoromethylsulfonate, phthalimidotrifluoromethylsulfonate, N-hydroxy Naphthalimide methanesulfonate, N-hydroxy-5-norbornene-2,3-dicarboximidepropanesulfonate and the like can be mentioned.

  Examples of the oxime sulfonate-based radiation-sensitive acid generator include (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl) acetonitrile and (5-octylsulfonyloxyimino-5H-thiophene). -2-ylidene)-(2-methylphenyl) acetonitrile, (camphorsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl) acetonitrile, (5-p-toluenesulfonyloxyimino-5H-thiophene) -2-ylidene)-(2-methylphenyl) acetonitrile, (5-octylsulfonyloxyimino)-(4-methoxyphenyl) acetonitrile and the like.

  Examples of the quinonediazide compound include 1,2-naphthoquinonediazidesulfonic acid ester of trihydroxybenzophenone, 1,2-naphthoquinonediazidesulfonic acid ester of tetrahydroxybenzophenone, 1,2-naphthoquinonediazidesulfonic acid ester of pentahydroxybenzophenone, hexa Examples thereof include 1,2-naphthoquinonediazidosulfonic acid ester of hydroxybenzophenone and 1,2-naphthoquinonediazidosulfonic acid ester of (polyhydroxyphenyl) alkane.

  Examples of the 1,2-naphthoquinonediazidosulfonic acid ester of trihydroxybenzophenone include 2,3,4-trihydroxybenzophenone-1,2-naphthoquinone azide-4-sulfonic acid ester and 2,3,4-trihydroxybenzophenone -1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,4,6-trihydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,4,6-trihydroxybenzophenone-1,2 -Naphthoquinonediazide-5-sulfonic acid ester.

  Examples of the 1,2-naphthoquinonediazidosulfonic acid ester of tetrahydroxybenzophenone include, for example, 2,2 ′, 4,4′-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,2 ′, 4,4′-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,3,4,3′-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester 2,3 , 4,4'-tetrahydroxy-3'-methoxybenzophenone-1,2-naphthoquinonediazido-5-sulfonic acid ester.

  Examples of the 1,2-naphthoquinonediazidosulfonic acid ester of pentahydroxybenzophenone include 2,3,4,2 ′, 6′-pentahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester and 2,3 , 4,2 ', 6'-pentahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester and the like.

  Examples of the 1,2-naphthoquinonediazidesulfonic acid ester of hexahydroxybenzophenone include, for example, 2,4,6,3 ′, 4 ′, 5′-hexahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 2,4,6,3 ′, 4 ′, 5′-hexahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid ester, 3,4,5,3 ′, 4 ′, 5′-hexahydroxybenzophenone -1,2-naphthoquinonediazide-4-sulfonic acid ester and the like.

  Examples of the 1,2-naphthoquinonediazidesulfonic acid ester of (polyhydroxyphenyl) alkane include bis (2,4-dihydroxyphenyl) methane-1,2-naphthoquinonediazide-4-sulfonic acid ester and bis (2,4 -Dihydroxyphenyl) methane-1,2-naphthoquinonediazide-5-sulfonic acid ester, bis (p-hydroxyphenyl) methane-1,2-naphthoquinonediazide-4-sulfonic acid ester, and the like.

  The radiation-sensitive acid generator is preferably an oxime sulfonate-based radiation-sensitive acid generator and a quinonediazide compound, and is preferably (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl) acetonitrile. And 1,1,1-tri (p-hydroxyphenyl) ethane-1,2-naphthoquinonediazide-5-sulfonic acid ester are more preferred.

Specific examples of the radiation-sensitive base generator include, for example, 4- (methylthiobenzoyl) -1-methyl-1-morpholinoethane, (4-morpholinobenzoyl) -1-benzyl-1-dimethylaminopropane, 2-benzyl- Radiation sensitivity containing a heterocyclic group such as 2-dimethylamino-1- (4-morpholinophenyl) -butanone, N- (2-nitrobenzyloxycarbonyl) pyrrolidine, 1- (anthraquinone-2-yl) ethylimidazolecarboxylate. Base generator;
2-nitrobenzylcyclohexyl carbamate, [[(2,6-dinitrobenzyl) oxy] carbonyl] cyclohexylamine, bis [[(2-nitrobenzyl) oxy] carbonyl] hexane-1,6-diamine, triphenylmethanol, o -Carbamoylhydroxylamide, o-carbamoyloxime, hexaamminecobalt (III) tris (triphenylmethylborate), 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidium n-butyltriphenylborate From the viewpoint of further promoting the thiolation reaction of the compound [B], 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidium n-butyltriphenylborate is preferred.

When the curable composition contains the photosensitive agent [B], the lower limit of the content of the photosensitive agent [B] is 0.5 parts by mass with respect to 100 parts by mass of the compound [A] having a polymerizable group. Preferably, 1.0 part by mass is more preferable. Further, the upper limit of the content is preferably 30 parts by mass, more preferably 25 parts by mass, per 100 parts by mass of the compound having a polymerizable group [A]. By setting the content to the above range, the radiation sensitivity of the curable composition can be further increased.
[C] Thermally-activated delayed fluorescent compound Thermally-activated delayed fluorescence (also referred to as TADF) has the same spectrum as normal fluorescence, but has a longer life than normal fluorescence. . Delayed fluorescent material means a material that emits such delayed fluorescence. The life of the delayed fluorescence emitted by the delayed fluorescent material differs depending on the type of the delayed fluorescent material, for example, the one that is 1 μs or longer, the one that is 5 μs or longer, and the one that is 10 μs or longer.
In the present invention, a delayed fluorescent material having such properties is selected and used as a light emitting material. The mechanism of delayed fluorescence emission of the delayed fluorescent material used in the present invention is not particularly limited. Delayed fluorescence includes fluorescence emitted from the triplet state in the excited triplet state and crossed into the singlet state in the inverted state. The inverted crossing at this time is due to triplet-triplet annihilation. However, heat energy may be absorbed. In addition, the delayed fluorescence may involve exciplex. Further, the delayed fluorescent material used in the present invention is preferably a thermally activated delayed fluorescent material activated by heat.

  In the present invention, only a delayed fluorescent material may be used as a light emitting material, or a combination of a delayed fluorescent material and a light emitting material that does not emit delayed fluorescence may be used. A preferred embodiment uses only a delayed fluorescent material. The delayed fluorescent material used as the light emitting material of the present invention may be only one kind or a mixture of two or more kinds.

  As a preferred example of the delayed fluorescent material that can be used in the present invention, a compound having a structure represented by the following general formula (1) can be given.

In the general formulas (1) and (2), at least one of R ¹ to R ⁷ represents a cyano group. When any one is a cyano group, it may be any of R ¹ to R ³ . When any two are a cyano group, a combination of R ¹ and R ^{3 or} a combination of R ² and R ⁴ can be exemplified. When any three are cyano groups, examples of combinations of R ¹ , R ^3, and R ⁴ can be given.

In the general formulas (1) and (2), at least one of R ¹ to R ⁷ represents a group represented by the following general formula (X). When two or more represent the group represented by formula (X), they may be the same or different, but are preferably the same.

In the general formula (X), R ²¹ to R ²⁸ each independently represent a hydrogen atom or a substituent. However, at least one of the following <A> or <B> is satisfied. More preferably, both are satisfied.
<A> R ²⁵ and R ²⁶ together form a single bond.
<B> R ²⁷ and R ²⁸ together represent an atomic group necessary to form a substituted or unsubstituted benzene ring.

The group represented by the general formula (X) is a substituted or unsubstituted 9-carbazolyl group, a substituted or unsubstituted 1,2,3,4-tetrahydro-9-carbazolyl group, 3,6-di (t- (Butyl) -9-carbazolyl group, a substituted or unsubstituted 1-indolyl group, or a substituted or unsubstituted diarylamino group. That is, in formulas (1) and (2), any one of R ¹ to R ⁷ is a substituted or unsubstituted 9-carbazolyl group or a substituted or unsubstituted 1,2,3,4-tetrahydro- It is preferably a 9-carbazolyl group, a substituted or unsubstituted 1-indolyl group, or a substituted or unsubstituted diarylamino group. In formula (1), any two or more of R ¹ to R ⁵ are a substituted or unsubstituted 9-carbazolyl group, a substituted or unsubstituted 1,2,3,4-tetrahydro-9-carbazolyl group, More preferably, it is a substituted or unsubstituted 1-indolyl group or a substituted or unsubstituted diarylamino group.

  The group represented by the general formula (X) is particularly preferably a substituted or unsubstituted 9-carbazolyl group or 3,6-di (t-butyl) -9-carbazolyl group.

Examples of R ²¹ to R ^{28 in} the general formula (X) include a hydroxy group, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an alkylthio group having 1 to 20 carbon atoms. An alkyl-substituted amino group having 1 to 20 carbon atoms, an acyl group having 2 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, a heteroaryl group having 3 to 40 carbon atoms, a diarylamino group having 12 to 40 carbon atoms, A substituted or unsubstituted carbazolyl group having 12 to 40 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, and an alkylsulfonyl having 1 to 10 carbon atoms A haloalkyl group having 1 to 10 carbon atoms, an amide group, an alkylamide group having 2 to 10 carbon atoms, a trialkylsilyl group having 3 to 20 carbon atoms, and a trialkylsilyl group having 4 to 20 carbon atoms. Le Kill silylalkyl group, trialkylsilyl alkenyl group having 5 to 20 carbon atoms and an trialkylsilyl alkynyl group and a nitro group having 5 to 20 carbon atoms. Among these specific examples, those that can be further substituted by a substituent may be substituted. More preferred substituents include a halogen atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, A substituted or unsubstituted heteroaryl group having 3 to 40 carbon atoms; a substituted or unsubstituted diarylamino group having 12 to 40 carbon atoms; and a substituted or unsubstituted carbazolyl group having 12 to 40 carbon atoms. More preferred substituents are a fluorine atom, a chlorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, and a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms. Or an unsubstituted dialkylamino group, a substituted or unsubstituted aryl group having 6 to 15 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

  The alkyl group referred to in the present specification may be linear, branched, or cyclic, more preferably has 1 to 6 carbon atoms, and specific examples include a methyl group, an ethyl group, a propyl group, and a butyl group. Group, t-butyl group, pentyl group, hexyl group and isopropyl group. The aryl group may be a single ring or a fused ring, and specific examples include a phenyl group and a naphthyl group. The alkoxy group may be linear, branched, or cyclic, and more preferably has 1 to 6 carbon atoms. Specific examples include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a t-butoxy group. Group, pentyloxy group, hexyloxy group and isopropyloxy group. The two alkyl groups of the dialkylamino group may be the same or different from each other, but are preferably the same. The two alkyl groups of the dialkylamino group may be each independently linear, branched, or cyclic, more preferably 1 to 6 carbon atoms, and specific examples include a methyl group, an ethyl group, Examples thereof include a propyl group, a butyl group, a pentyl group, a hexyl group, and an isopropyl group. The aryl group may be a single ring or a fused ring, and specific examples include a phenyl group and a naphthyl group. The heteroaryl group may be a single ring or a fused ring, and specific examples include a pyridyl group, a pyridazyl group, a pyrimidyl group, a triazyl group, a triazolyl group, and a benzotriazolyl group. These heteroaryl groups may be groups bonded via a hetero atom or groups bonded via carbon atoms constituting a heteroaryl ring.

In Formulas (1) and (2), when any one of R ¹ to R ⁷ is a group represented by Formula (X), it may be any of R ¹ to R ³ . When any two are groups represented by the general formula (X), a combination of R ¹ and R ^{3 or} a combination of R ² and R ⁴ can be exemplified. When any three are groups represented by the general formula (X), a combination of R ¹ , R ³ and R ⁴ can be exemplified.

  One of the two ortho positions of the benzene ring to which the group represented by the general formula (X) is bonded is preferably a cyano group. Both of the two ortho positions may be cyano groups. When two or more groups represented by the general formula (X) are bonded to the benzene ring, at least two of the benzene groups are bonded to a benzene group bonded to the group represented by the general formula (X). Preferably, one of the two ortho positions of the ring satisfies the condition that it is a cyano group.

Formula (1), (2), at least one of ^{R 7} from ^{R 1} represents a cyano group, at least one of ^{R 1} to ^{R 7} represents a group represented by the general formula (X) And the remaining R ¹ to R ⁷ can represent a hydrogen atom or a substituent.

Preferred substituents that R ¹ to R ⁷ can take are, for example, a hydroxy group, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, -20 alkyl-substituted amino group, C2-C20 acyl group, C6-C40 aryl group, C3-C40 heteroaryl group, C2-C10 alkenyl group, C2-C10 An alkynyl group, an alkoxycarbonyl group having 2 to 10 carbon atoms, an alkylsulfonyl group having 1 to 10 carbon atoms, an amide group, an alkylamide group having 2 to 10 carbon atoms, a trialkylsilyl group having 3 to 20 carbon atoms, and a carbon number A trialkylsilylalkyl group having 4 to 20 carbon atoms, a trialkylsilylalkenyl group having 5 to 20 carbon atoms, a trialkylsilylalkynyl group having 5 to 20 carbon atoms, and nitrite Group, and the like. Among these specific examples, those that can be further substituted by a substituent may be substituted. More preferred substituents are a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and a substituted or unsubstituted 1 to 20 carbon atoms. A substituted or unsubstituted aryl group having 6 to 40 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 40 carbon atoms. More preferred substituents are a hydroxy group, a fluorine atom, a chlorine atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, and a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms. Or an unsubstituted dialkylamino group, a substituted or unsubstituted aryl group having 6 to 15 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. Still more preferably, they are a hydroxy group, a fluorine atom and a chlorine atom.

In the general formulas (1) and (2), among R ¹ to R ^7, a hydrogen atom is preferably 3 or less, more preferably 2 or less, and more preferably 1 or less. More preferably, it is also preferably 0.

  Preferred examples of specific compounds include compounds represented by the following formulas (4), (5), (6), and (7). In the formula (7), tBU represents a t-butyl group.

In the curable composition, the content of the heat-activated delayed fluorescent compound [C] is in the range of 0.01 to 5, more preferably 0.05 to 1, based on the total content of the photosensitizer [B]. Range. Within this range, it is possible to form a cured film having excellent solvent resistance while increasing the radiation sensitivity of the cured film formation.

The curable composition may contain a solvent in addition to the above components. When the curable composition contains a solvent, coatability is improved. The solvent is not particularly limited as long as the above components can be dissolved or dispersed, and examples thereof include a solvent used in synthesizing the above-mentioned [a] polymer. In addition, a solvent may be used independently and may be used in combination of 2 or more types.
[Other ingredients]
The curable composition may contain other components such as other polymers and additives as long as the object of the present invention is not impaired. Other components include, for example, surfactants, fillers such as inorganic particles, antioxidants, ultraviolet absorbers, and polymers such as polyimide. The content of these additives can be appropriately selected within a range that does not impair the purpose of the present invention.

The curable composition can be prepared by an appropriate method. For example, in a solvent, [A] a compound having a polymerizable group, [B] a compound, and if necessary, an optional component are mixed. Can be prepared. The lower limit of the solid content in the composition at the time of mixing is preferably 5% by mass, more preferably 10% by mass. The upper limit of the concentration is preferably 50% by mass, more preferably 40% by mass. By setting the solid content concentration in the above range, coatability can be improved. In this specification, “solid content” refers to a residue obtained by drying a sample on a hot plate at 175 ° C. for 1 hour to remove volatile substances.
<Curing film>
The cured film is obtained from the curable composition. Examples of the cured film include a protective film, an interlayer insulating film, and a flattening film. Since the cured film is obtained from the curable composition, the cured film has high hardness and excellent solvent resistance. The method for forming the cured film is not particularly limited, but it is preferable to apply the method for forming a cured film described later.
<Display element>
The display element has the cured film. That is, the cured film can be suitably used for a display element. Examples of the display element include a liquid crystal display element, an organic EL element, and an electronic paper element. Since the display element has the cured film having high hardness and excellent solvent resistance, for example, the yield can be increased and the durability can be improved.
<Method of forming cured film>
The method for forming the cured film includes a step of forming a coating film from the curable composition (hereinafter, also referred to as a “coating film forming step”) and a step of irradiating (exposing) radiation to at least a part of the coating film. (Hereinafter, also referred to as “radiation irradiation step”), a step of developing the coating film irradiated with the radiation (hereinafter, also referred to as “development step”), and a step of heating the developed coating film (hereinafter, referred to as “developing step”). , "Heating step"). The method for forming the cured film includes, as an optional step, a step of heating the coating film irradiated with the radiation (hereinafter, also referred to as a “PEB step”) between the irradiation step and the development step. May be.

According to the method for forming a cured film, since the curable composition described above is used, a cured film having high hardness and excellent solvent resistance can be easily and efficiently formed. Hereinafter, each step will be described.
[Film formation step]
In this step, after the curable composition is applied to a surface on which a cured film is to be formed, such as a substrate surface, a solvent or the like is preferably removed by heating (prebaking) the applied surface to form a coating film. Examples of the material of the substrate include glass, quartz, silicon, and resin. Specific examples of the resin include, for example, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, polyimide, addition polymers of cyclic olefins, ring-opening polymers of cyclic olefins and hydrogenated products thereof. Can be

The method for applying the curable composition is not particularly limited, and for example, an appropriate method such as a spray method, a roll coating method, a spin coating method (spin coating method), a slit die coating method, or a bar coating method may be employed. it can. Among these coating methods, spin coating and slit die coating are particularly preferred. The prebaking conditions vary depending on the type, blending ratio, and the like of each component. For example, the heating time may be 1 minute to 10 minutes at a temperature of 70 ° C to 130 ° C.
[Radiation irradiation step]
In this step, a part of the coating film formed in the coating film forming step is irradiated with radiation. Usually, when irradiating a part of the coating film with radiation, the radiation is applied through a photomask having a predetermined pattern. As the radiation, for example, visible light, ultraviolet light, far ultraviolet light, electron beam, X-ray and the like can be used. Among these radiations, radiation having a wavelength in the range of 190 nm to 450 nm is preferable, and radiation containing ultraviolet light of 365 nm is more preferable.

The lower limit of the exposure amount in this step is preferably 10 mJ / cm ^2, more preferably 20 mJ / cm ² , as a value obtained by measuring the intensity of radiation at a wavelength of 365 nm with an illuminometer (“OAI model 356” manufactured by OAI Optical Associates Inc.). More preferred. The upper limit of the amount of exposure, as measured by the luminometer, preferably ^{2,000mJ / cm 2, 1,000mJ / cm} 2 is more preferable.
[Development step]
In this step, a predetermined pattern is formed by developing the coating film after irradiation with a developer. As the developer, an alkali developer is preferable. Examples of the alkaline developer include an alkaline developer in which at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, tetramethylammonium hydroxide, and tetraethylammonium hydroxide is dissolved. Aqueous solution and the like. Further, a suitable amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant may be added to the alkali developer.

As a developing method, for example, an appropriate method such as a liquid filling method, a dipping method, a rocking immersion method, a spray method, or the like can be adopted. The development time varies depending on the composition of the curable composition, but is, for example, 10 seconds or more and 180 seconds or less. Subsequent to such a development process, a desired pattern can be formed by, for example, performing running water washing for a processing time of 30 seconds or more and 90 seconds or less, and then air-drying with, for example, compressed air or compressed nitrogen.
[Heating process]
In this step, a cured film having a desired pattern is obtained by heating (post-baking) the developed and patterned coating using a heating device such as a hot plate or an oven. As a minimum of heating temperature, 80 ° C is preferred, 120 ° C is more preferred, and 150 ° C is still more preferred. The heating time varies depending on the type of the heating device, and may be, for example, 5 minutes to 30 minutes when heating on a hot plate, and 10 minutes to 90 minutes when heating in an oven. The heating may be performed in air or in an atmosphere of an inert gas such as nitrogen or argon. Further, a step baking method in which a heating step is performed twice or more can be used. The average thickness of the cured film thus formed is, for example, 0.1 μm or more and 10 μm or less. The order of the exposure or heating step may be different.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples.
[Weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn)]
Mw and Mn were measured by gel permeation chromatography (GPC) under the following conditions. The molecular weight distribution (Mw / Mn) was calculated from the obtained Mw and Mn.

Equipment: Showa Denko “GPC-101”
Column: a column in which "GPC-KF-801", "GPC-KF-802", "GPC-KF-803" and "GPC-KF-804" of Showa Denko KK are connected.

Mobile phase: tetrahydrofuran Column temperature: 40 ° C
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: differential refractometer Standard material: monodispersed polystyrene ^[1 H-NMR analysis]
^{The 1} H-NMR analysis used a nuclear magnetic resonance apparatus (“ECX400P” manufactured by JEOL Ltd.).
<Synthesis of polymer>
[Synthesis Example 1] Synthesis of polymer (A-1) In a flask equipped with a cooling tube and a stirrer, 11 parts by mass of 2,2'-azobis (2,4-dimethylvaleronitrile) and 300 parts by mass of propylene glycol monomethyl ether The department was charged. Next, 75 parts by mass of methacrylic acid and 25 parts by mass of benzyl methacrylate were charged, and after purging with nitrogen, the temperature of the solution was increased to 70 ° C. while gently stirring, and the temperature was maintained for 5 hours to carry out polymerization. Thereafter, the temperature of the solution was set to 100 ° C., and after stirring for 1 hour, the temperature was returned to room temperature. Next, 50 parts by weight of glycidyl methacrylate and 2 parts by weight of tetrabutylammonium bromide were added, the temperature of the solution was raised to 90 ° C., and this temperature was maintained for 9 hours for reaction. Thus, a polymer solution containing the polymer (A-1) having a methacryloyl group in a side chain was obtained. The solid concentration of this polymer solution was 23.0% by mass, the Mw of the polymer (A-1) was 11,000, and the molecular weight distribution (Mw / Mn) was 2.0.
[Synthesis Example 2] Synthesis of polymer (A-2) In a flask equipped with a cooling tube and a stirrer, 200 parts of cresol novolak type epoxy resin "EOCN-1020" (Nippon Kayaku Co., Ltd., epoxy equivalent 200) and propylene glycol 245 parts of monomethyl ether acetate were charged and heated to 110 ° C. to dissolve uniformly. Subsequently, 76 parts (1.07 mol) of acrylic acid, 2 parts of triphenylphosphine, and 0.2 part of p-methoxyphenol were charged and reacted at 110 ° C. for 10 hours. The reaction mixture was further charged with 91 parts (0.60 mol) of tetrahydrophthalic anhydride and reacted at 90 ° C. for 5 hours. After cooling, propylene glycol monomethyl ether acetate was added to adjust the solid content, and the carboxyl group and acryloyl group were added. A propylene glycol monomethyl ether acetate solution of the polymer having a group (A-2) (Mn: 2,200) was obtained (solid content 25%).
[Synthesis Example 4] Synthesis of polymer (A-6) In a flask equipped with a cooling tube and a stirrer, 7 parts by mass of 2,2'-azobis (2,4-dimethylvaleronitrile) and 200 parts by mass of diethylene glycol ethyl methyl ether were added. The department was charged. Subsequently, 16 parts by mass of methacrylic acid, 16 parts by mass of tricyclo [5.2.1.02,6] decane-8-yl methacrylate, 38 parts by mass of methyl methacrylate, 10 parts by mass of styrene, and 20 parts by mass of glycidyl methacrylate were charged. After the replacement, the temperature of the solution was raised to 70 ° C. with gentle stirring, and the temperature was maintained for 4 hours to carry out polymerization to obtain a solution containing the polymer (A-6) (solid content). Concentration = 34.4% by mass, Mw = 8,000, Mw / Mn = 2.3).
<Preparation of curable composition, formation of cured film, and evaluation of physical properties>
The components used for preparing each curable composition are shown below.
[[A] component]
A-1: Polymer (A-1)
A-2: Polymer (A-2)
A-3: Fluorene diacrylate ("OGSOL EA-0200" of Osaka Gas Chemical Company)
A-4: Tris (4-hydroxyphenyl) ethane triglycidyl ether A-5: Dipentaeristol hexaacrylate ("KAYARAD DPHA" of Nippon Kayaku Co., Ltd.)
A-6: Polymer (A-6)
[B] [Radiation-sensitive radical polymerization initiator]
B1-1: 1- [9-ethyl-6- (2-methylbenzoyl) -9. H. -Carbazol-3-yl] -ethane-1-one oxime-O-acetate (“IRGACURE OX02” from BASF)
B1-2: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name “Irgacure 819”, manufactured by BASF)
B1-3: 2,2'-bis (2,4-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole 10 parts by mass, 4,4'-bis (dimethylamino) benzophenone 10 parts by mass , A mixture of 5 parts by mass of 2-mercaptobenzothiazole B1-4: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one (trade name “Irgacure 907”, manufactured by BASF)
[Radiation-sensitive acid generator]
B2-1: (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl) acetonitrile (“IRGACURE PAG 103” from BASF)
[Radiation-sensitive base generator]
B3-1: 1,2-Dicyclohexyl-4,4,5,5-tetramethylbiguanidium n-butyltriphenylborate ("WPBG-300" manufactured by Wako Pure Chemical Industries, Ltd.)
[[C] component]
C-1: Compound (4)
C-2: Compound (5)
C-3: Compound (6)
C-4: Compound (7)

[Example 1]
The polymer (A-1) as the component (A) was added to propylene glycol monodimethyl ether acetate (PGMEA) (100 parts by mass in terms of solid content), 10 parts by mass of the component (B1-1), 1 part by mass of the component (C-1), 0.1 part by mass of SH 190 (manufactured by Dow Corning Toray Silicone) as a surfactant, and mixing and stirring, then using a 0.2 μm filter. The mixture was filtered to prepare a curable composition.
[Examples 2 to 9 and Comparative Examples 1 and 2]
Each curable composition was prepared in the same manner as in Example 1, except that the types and amounts of the components were as shown in Table 1 below. In addition, "-" in Table 1 shows that the corresponding component was not used.

Each of the obtained curable compositions was evaluated according to the following method. Table 1 shows the evaluation results.
[Storage stability]
The evaluation of storage stability was performed by measuring the time until the viscosity when the curable composition was stored at 25 ° C. reached 10 times the viscosity immediately after preparation. The viscosity was measured using an “ELD viscometer” manufactured by Tokyo Keiki Co., Ltd. under the conditions of 25 ° C. and 20 rpm. The longer the time until the viscosity reaches 10 times the viscosity immediately after preparation, the better the storage stability. For example, when the viscosity is 800 hours or more, the storage stability can be evaluated as good. Table 1 shows the results.
[hardness]
The hardness was evaluated by a pencil hardness meter based on JIS K 5600-5-4 (1999) for a cured film formed from the curable composition by the following forming method. When the hardness is H or more, it can be evaluated as good. Table 1 shows the results.
(Method of forming cured film)
The curable composition was applied on a non-alkali glass substrate using a spinner, and then prebaked on a hot plate at 90 ° C. for 3 minutes to form a coating film having an average thickness of 3 μm. The obtained coating film was exposed to radiation containing each wavelength of 365 nm, 405 nm and 436 nm using a high-pressure mercury lamp without a photomask at an integrated irradiation dose of 300 mJ / cm ² . Then, it was heated in an oven at 150 ° C. for 30 minutes to obtain a cured film.
[Solvent resistance]
The solvent resistance was evaluated by measuring the rate of change in the average thickness of the cured film formed from the curable composition before and after immersion in acetone according to the following method. The formation of the cured film was performed in the same manner as in the evaluation of the hardness. Table 1 shows the results.
(Method of measuring the rate of change in average thickness)
The average thickness (T1) of the cured film after formation and the average thickness (T2) after immersion in acetone for 20 minutes were measured, and the rate of change was calculated by the following equation. In addition, when the rate of change of the average thickness is 5% or less, it can be evaluated that the solvent resistance is good.

Change rate (%) of average thickness = {(T1-T2) / T1} × 100
[Radiation sensitivity]
The radiation sensitivity of the cured film formed from the curable composition was evaluated based on the amount of exposure when the hardness measured using a pencil hardness tester reached H, as in the evaluation of the hardness described above. The method for forming the cured film was the same as that for the hardness evaluation except that the exposure amount was arbitrarily changed. If the radiation sensitivity is 100 mJ / cm ² or less, it can be evaluated as good. Table 1 shows the results.

In the table, "-" indicates that no compound was added.
As described above, the curable composition of the present invention contains (A) a compound having a polymerizable group, (B) a photosensitizer, and (C) a thermally activated delayed fluorescent compound, as shown in the results in Table 1. It shows that the curable composition can form a cured film having high hardness and excellent solvent resistance even with a film obtained by a curing and baking process at a temperature of 200 ° C. or lower while improving storage stability and radiation sensitivity. Was done.

Claims (10)

(A) Compound having a polymerizable group (B) Photocuring agent (C) Curable composition containing thermally activated delayed fluorescent compound The curable composition according to claim 1, wherein the (C) thermally activated delayed fluorescent compound is a compound represented by the following formula (1) or (2).

(In the formulas (1) and (2), at least one of R ¹ to R ⁷ is a hydrogen atom, an alkyl having 1 to 12 carbons, a phenyl group, a tolyl group, a naphthyl group, a cyano group, a formula (X) Represents the group represented.
In the formula (X), R ²¹ to R ²⁸ each independently represent a hydrogen atom or a substituent. However, <A> which satisfies at least one of <A> and <B> is R ²⁵ and R ²⁶ together form a single bond.
<B> R ²⁷ and R ²⁸ together form a substituted or unsubstituted benzene ring. ) The above formula (X) represents a 9-carbazolyl group, a 3,6-di (t-butyl) -9-carbazolyl group, a substituted or unsubstituted 1,2,3,4-tetrahydro-9-carbazolyl group, The curable composition according to claim 1, which represents an unsubstituted 1-indolyl group or a substituted or unsubstituted diarylamino group. The curing according to any one of claims 1 to 3, wherein the polymerizable group of the compound having a polymerizable group (A) is at least one selected from an epoxy group, a vinyl group, and a (meth) acryloyl group. Composition   The curable composition according to any one of claims 1 to 4, further comprising (D) a binder resin.   The curable composition according to any one of claims 1 to 5, wherein the photosensitive agent (B) is at least one selected from an acid generator, a base generator, and a radical polymerization initiator.   The curable composition according to any one of claims 1 to 6, wherein the photosensitizer is a radical polymerization initiator containing a condensed ring. The content ratio of the thermally activated delayed fluorescent compound (C) to the total content of the photosensitive agent (B) is in the range of 0.01 to 5, and any one of claims 1 to 7. Curable composition described in A method for forming a cured film comprising the following steps (1): a step of forming a coating film of the curable composition according to any one of claims 1 to 8 on a substrate (2) exposing the coating film Or heating at 80 ° C to 150 ° C A display element having a cured film obtained by the method for forming a cured film according to claim 9.