WO2022107599A1

WO2022107599A1 - Inkjet ink composition, cured product thereof, light conversion layer, color filter, and light emitting element

Info

Publication number: WO2022107599A1
Application number: PCT/JP2021/040511
Authority: WO
Inventors: 浩一延藤
Original assignee: Dic株式会社
Priority date: 2020-11-19
Filing date: 2021-11-04
Publication date: 2022-05-27
Also published as: CN116323829A; KR20230107798A; JP2022081110A; TW202237760A

Abstract

Provided is an inkjet ink composition having excellent curing properties, a cured product thereof, a light conversion layer, a color filter, and a light emitting element. The present invention solves the above problem by providing an inkjet ink composition comprising: light-emitting particles including semiconductor nanocrystal particles comprising a metal halide; a photopolymerizable compound; a photosensitizer; and a photopolymerization initiator, wherein the photosensitizer is a thioxanthone composition represented by general formula (1) or a benzophenone composition represented by general formula (2). (1) (In formula (1), R1 represents a C2-C3 alkyl group or the like, and m represents an integer of 1-4.) (2) (In formula (2), R2 and R3 each independently represent an alkyl group or the like, and n and o each independently represent an integer of 0-5).

Description

Inkjet ink composition and its cured product, light conversion layer, color filter and light emitting element

The present invention relates to an ink jet ink composition and a cured product thereof, an optical conversion layer, a color filter, and a light emitting element.

In recent years, there has been a strong demand for higher color gamut of displays. Therefore, a color having a pixel portion such as a red pixel or a green pixel using luminescent nanocrystal particles such as quantum dots, quantum rods, and other inorganic phosphor particles instead of the red organic pigment particles or the green organic pigment particles. Research on filters is becoming more active. Since it is desired that the color filter has a fine pattern and the photolithography method wastefully consumes luminescent nanocrystal particles, an inkjet method (inkjet method) using an ultraviolet curable ink composition is used. It is being studied to form an optical conversion layer. For example, Patent Document 1 discloses an ink jet ink composition containing luminescent nanocrystal particles composed of core-shell type semiconductor nanocrystals.

Further, semiconductor nanocrystals made of metal halide, particularly semiconductor nanocrystals having a perovskite-type crystal structure, have been found and are attracting attention (see, for example, Patent Document 2). The perovskite-type semiconductor nanocrystals consist of, for example, a compound represented by CsPbX ₃ (X represents Cl, Br or I). Compared with core-shell type semiconductor nanocrystals, perovskite-type semiconductor nanocrystals have the advantage that the emission wavelength can be controlled by adjusting the abundance ratio of halogen atoms in addition to the particle size effect.

Japanese Unexamined Patent Publication No. 2020-76976 Special Table 2018-506625

However, semiconductor nanocrystal particles made of metal halides such as perovskite-type semiconductor nanocrystal particles have a large absorbance in the ultraviolet region. Therefore, in the inkjet ink composition disclosed in Patent Document 1, simply replacing the core-shell type quantum dots with perovskite-type semiconductor nanocrystal particles is sufficient to sufficiently cure the coating film formed by the ink composition. There was the inconvenience of being difficult.

Therefore, an object to be solved by the present invention is to provide an inkjet ink composition having excellent curability, a cured product thereof, an optical conversion layer, a color filter, and a light emitting element.

The present invention contains a luminescent particle containing semiconductor nanocrystal particles made of metal halide, a photopolymerizable compound, a photosensitizer, and a photopolymerization initiator.
The photosensitizer is based on the following general formula (1):

[In the formula (1), R ¹ represents an alkyl group, a hydroxy group, or an alkoxycarbonyl group having 2 to 3 carbon atoms, m represents an integer of 1 to 4, and m is an integer of 2 to 4. In some cases, the plurality of R ^1s may be the same or different from each other. ]
The thioxanthone compound represented by, or the following general formula (2):

[In formula (2), R ² and R ³ independently represent an alkyl group, a hydroxy group, a dialkylamino group, and a phenyl group, n and o each independently represent an integer of 0 to 5, and n is 2. When it is an integer of ~ 5, multiple R ^2s may be the same or different from each other, and when o is an integer of 2 to 5, multiple R ^3s may be the same or different from each other. May be. ]
The present invention relates to an ink composition for inkjet, which is a benzophenone compound represented by.

The present invention relates to a cured product of an ink jet ink composition.

The present invention includes a plurality of pixel portions and a light-shielding portion provided between the plurality of pixel portions, and the plurality of pixel portions have a light emitting pixel portion including a cured product of the ink composition. Regarding the conversion layer.

The present invention relates to a color filter provided with the above-mentioned optical conversion layer.

The present invention relates to a light emitting device provided with the above color filter.

According to the present invention, it is possible to provide an ink composition for inkjet having excellent curability. According to the present invention, it is possible to provide a cured product of the inkjet ink composition, an optical conversion layer using the cured product, a color filter, and a light emitting element.

FIG. 1 is a schematic cross-sectional view of a color filter according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments.

<Ink composition>
One embodiment of the present invention is an inkjet ink composition (hereinafter, also simply referred to as “ink composition”). The ink composition according to one embodiment includes luminescent particles containing semiconductor nanocrystal particles made of metal halide (hereinafter, also simply referred to as “nanocrystal particles”), a photopolymerizable compound, a photosensitizer, and photopolymerization. Contains, and an initiator.

The ink composition is, for example, an ink composition for forming an optical conversion layer (for example, for forming a color filter pixel portion) used for forming an optical conversion layer (pixel portion of the optical conversion layer) of a color filter or the like. May be. The ink composition is a composition (inkjet ink) used in an inkjet method. Since the ink composition of one embodiment contains the compound represented by the general formula (1) or the general formula (2) as the photosensitizer, the amount of the photosensitizer and the photopolymerization initiator added is small. However, excellent curability can be ensured, and the productivity of the optical conversion layer can be improved. Further, the ink composition contains a compound represented by the general formula (1) or the general formula (2) as a photosensitizer to reduce the amount of the photosensitizer and the photopolymerization initiator added. Therefore, it is possible to suppress an increase in viscosity. Since the photosensitizer absorbs ultraviolet rays irradiated for curing, the ink composition suppresses the absorption of ultraviolet rays of the nanocrystal particles themselves as compared with the case where the photosensitizer is not contained. can do. Further, since the ink composition has an appropriate ink viscosity and excellent dispersibility as described later, clogging of the inkjet head is less likely to occur and the frequency of replacement of the inkjet head can be reduced.

<< Luminous particles >>
Luminous particles include nanocrystalline particles. Nanocrystal particles are nano-sized crystals (nanocrystal particles) composed of metal halides, which absorb excitation light and emit fluorescence or phosphorescence. As the luminescent nanocrystal made of metal halide, for example, quantum dots having a perovskite-type crystal structure described later are preferable. The nanocrystal particles are, for example, crystals having a maximum particle size of 100 nm or less as measured by a transmission electron microscope or a scanning electron microscope.
The nanocrystal particles can be excited by, for example, light energy or electrical energy of a predetermined wavelength and emit fluorescence or phosphorescence.

The nanocrystal particles made of metal halide are compounds represented by the general formula: A _a M _b X _c .
In the formula, A is at least one of an organic cation and a metal cation. Examples of the organic cation include ammonium, formamidinium, guanidinium, imidazolium, pyridinium, pyrrolidinium, protonated thiourea and the like, and examples of the metal cation include cations such as Cs, Rb, K, Na and Li.
M is at least one metal cation. Metal cations are selected from Group 1, Group 2, Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 13, Group 14, and Group 15. Examples include cations. More preferably, Ag, Au, Bi, Ca, Ce, Co, Cr, Cu, Eu, Fe, Ga, Ge, Hf, In, Ir, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, Examples thereof include cations such as Pb, Pd, Pt, Re, Rh, Ru, Sb, Sc, Sm, Sn, Sr, Ta, Te, Ti, V, W, Zn, and Zr.
X is at least one anion. Examples of the anion include chloride ion, bromide ion, iodide ion, cyanide ion and the like, and include at least one halogen.
a is 1 to 7, b is 1 to 4, and c is an integer of 3 to 16.

The compounds represented by the general formula A _a M _b X _c are specifically AMX, A ₄ MX, AMX ₂ , AMX ₃ , A ₂ MX ₃ , AM ₂ X ₃ , A ₂ MX ₄ , A ₂ MX ₅ . , A ₃ MX ₅ , A ₃ M ₂ X ₅ , A ₃ MX ₆ , A ₄ MX ₆ , AM ₂ X ₆ , A ₂ MX ₆ , A ₄ M ₂ X ₆ , A ₃ MX ₈ , A ₃ M ₂ X Compounds represented by ₉ , A ₃ M ₃ X ₉ , A ₂ M ₂ X ₁₀ , and A ₇ M ₃ X ₁₆ are preferable.
In the formula, A is at least one of an organic cation and a metal cation. Examples of the organic cation include ammonium, formamidinium, guanidinium, imidazolium, pyridinium, pyrrolidinium, protonated thiourea and the like, and examples of the metal cation include cations such as Cs, Rb, K, Na and Li.
In the formula, M is at least one metal cation. Specifically, one kind of metal cation (M ¹ ), two kinds of metal cations (M ¹ _α M ² _β ), three kinds of metal cations (M ¹ _α M ² _β M ³ _γ ), and four kinds of metals. Examples thereof include cations (M ¹ _α M ² _β M ³ _γ M ⁴ _δ ). However, α, β, γ, and δ each represent a real number of 0 to 1, and represent α + β + γ + δ = 1. Metal cations are selected from Group 1, Group 2, Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 13, Group 14, and Group 15. Examples include cations. More preferably, Ag, Au, Bi, Ca, Ce, Co, Cr, Cu, Eu, Fe, Ga, Ge, Hf, In, Ir, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, Examples thereof include cations such as Pb, Pd, Pt, Re, Rh, Ru, Sb, Sc, Sm, Sn, Sr, Ta, Te, Ti, V, W, Zn, and Zr.
In the formula, X is an anion containing at least one halogen. Specific examples thereof include one type of halogen anion (X ¹ ) and two types of halogen anion (X ¹ _α X ² _β ). Examples of the anion include chloride ion, bromide ion, iodide ion, cyanide ion and the like, and include at least one halogen.

The compound composed of the metal halide represented by the general formula A _a M _b X _c is different from the metal cation used for the M site in order to improve the emission characteristics, and is different from Bi, Mn, Ca, Eu, Sb, Yb. It may be one to which a metal ion such as is added (doped).

Among the compounds composed of metal halides represented by the above general formula A _a M _b X _c , the compound having a perovskite type crystal structure is adjusted by adjusting its particle size, the type and abundance ratio of the metal cations constituting the M site. Further, the emission wavelength (emission color) can be controlled by adjusting the type and abundance ratio of the anions constituting the X-site, which is particularly preferable for use as luminescent nanocrystal particles. Since this adjustment operation can be easily performed, the perovskite-type semiconductor nanocrystal particles are characterized in that the emission wavelength is more easily controlled and therefore more productive than the conventional core-shell type semiconductor nanocrystal particles. Have. Specifically, compounds represented by AMX ₃ , A ₃ MX ₅ , A ₃ MX ₆ , A ₄ MX ₆ , and A ₂ MX ₆ are preferable. A, M and X in the formula are as described above. Further, as described above, the compound having a perovskite-type crystal structure was added (doped) with metal ions such as Bi, Mn, Ca, Eu, Sb, and Yb, which are different from the metal cations used for the M site. It may be a thing.

Among the compounds showing a perovskite type crystal structure, A is Cs, Rb, K, Na, Li, and M is one kind of metal cation (M ¹ ) or two kinds, in order to show better emission characteristics. It is a metal cation (M ¹ _α M ² _β ), and X is preferably a chloride ion, a bromide ion, or an iodide ion. However, α and β each represent a real number of 0 to 1, and represent α + β = 1. Specifically, M is selected from Ag, Au, Bi, Cu, Eu, Fe, Ge, K, In, Na, Mn, Pb, Pd, Sb, Si, Sn, Yb, Zn, and Zr. Is preferable.

As a specific composition of luminescent nanocrystal particles made of metal halide showing a perovskite-type crystal structure, nanocrystal particles using Pb as M such as CsPbBr ₃ , CH ₃ NH ₃ PbBr ₃ , and CHN ₂ H ₄ PbBr ₃ are described as nanocrystal particles. It is preferable because it has excellent light intensity and quantum efficiency. Further, luminescent nanocrystal particles using a metal cation other than Pb as M such as CsSnBr _{3, CsEuBr 3} _, and CsYbI ₃ are preferable because they have low toxicity and have little influence on the environment.

The nanocrystal particles may be red light emitting crystals that emit light having an emission peak in the wavelength range of 605 to 665 nm (red light), and may emit light having an emission peak in the wavelength range of 500 to 560 nm (green light). It may be a green luminescent crystal that emits light, or may be a blue luminescent crystal that emits light (blue light) having an emission peak in the wavelength range of 420 to 480 nm. Further, in one embodiment, a combination of these nanocrystal particles may be used.
The wavelength of the emission peak of the nanocrystal particles can be confirmed, for example, in the fluorescence spectrum or the phosphorescence spectrum measured by using an absolute PL quantum yield measuring device.

The red-emitting nanocrystal particles are 665 nm or less, 663 nm or less, 660 nm or less, 658 nm or less, 655 nm or less, 653 nm or less, 651 nm or less, 650 nm or less, 647 nm or less, 645 nm or less, 643 nm or less, 640 nm or less, 637 nm or less, 635 nm or less. It is preferable to have an emission peak in a wavelength range of 632 nm or less or 630 nm or less, and to have an emission peak in a wavelength range of 628 nm or more, 625 nm or more, 623 nm or more, 620 nm or more, 615 nm or more, 610 nm or more, 607 nm or more or 605 nm or more. Is preferable.
These upper and lower limit values can be combined arbitrarily. In the same description below, the upper limit value and the lower limit value described individually can be arbitrarily combined.

Green-emitting nanocrystal particles have emission peaks in the wavelength range of 560 nm or less, 557 nm or less, 555 nm or less, 550 nm or less, 547 nm or less, 545 nm or less, 543 nm or less, 540 nm or less, 537 nm or less, 535 nm or less, 532 nm or less, or 530 nm or less. It is preferable to have an emission peak in the wavelength range of 528 nm or more, 525 nm or more, 523 nm or more, 520 nm or more, 515 nm or more, 510 nm or more, 507 nm or more, 505 nm or more, 503 nm or more, or 500 nm or more.

Blue-emitting nanocrystal particles have emission peaks in the wavelength range of 480 nm or less, 477 nm or less, 475 nm or less, 470 nm or less, 467 nm or less, 465 nm or less, 463 nm or less, 460 nm or less, 457 nm or less, 455 nm or less, 452 nm or less, or 450 nm or less. It is preferable to have an emission peak in a wavelength range of 450 nm or more, 445 nm or more, 440 nm or more, 435 nm or more, 430 nm or more, 428 nm or more, 425 nm or more, 422 nm or more, or 420 nm or more.

The shape of the nanocrystal particles is not particularly limited, and may be any geometric shape or any irregular shape. Examples of the shape of the nanocrystal particles include a rectangular parallelepiped shape, a cubic shape, a spherical shape, a regular tetrahedron shape, an ellipsoidal shape, a pyramidal shape, a disc shape, a branch shape, a net shape, a rod shape and the like. The shape of the nanocrystal particles is preferably a rectangular parallelepiped shape, a cube shape, or a spherical shape.

The average particle diameter (volume average diameter) of the nanocrystal particles is preferably 40 nm or less, more preferably 30 nm or less, and further preferably 20 nm or less. The average particle size of the nanocrystal particles is preferably 1 nm or more, more preferably 1.5 nm or more, and further preferably 2 nm or more. Nanocrystal particles having such an average particle size are preferable because they easily emit light having a desired wavelength.
The average particle size of the nanocrystal particles is obtained by measuring with a transmission electron microscope or a scanning electron microscope and calculating the volume average diameter.

[Surface layer]
The luminescent particles may further include a surface layer formed on the surface of the nanocrystal particles. The surface layer may contain a siloxane compound having a binding group and a siloxane bond capable of binding to the surface of the nanocrystal particles.

The binding group that can be bound to the surface of the nanocrystal particles may be a binding group that binds (coordinates) to the cation contained in the nanocrystal particles. Examples of the binding group include a carboxyl group, an amino group, an ammonium group, a mercapto group, a phosphin group, a phosphin oxide group, a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfonic acid group, a boronic acid group and the like. .. Among them, the binding group is preferably at least one of a carboxyl group, a mercapto group and an amino group. These binding groups have a higher affinity for the cations contained in the nanocrystal particles than the reactive groups described above. Therefore, the siloxane compound can be coordinated with the binding group on the nanocrystal particle side to more easily and surely form nanocrystal particles having a surface layer.

The siloxane compound is formed by the reaction between precursor compounds having a binding group and a reactive group capable of forming a siloxane bond. As the reactive group, a hydrolyzable silyl group such as a silanol group or an alkoxysilyl group having 1 to 6 carbon atoms is preferable because a siloxane bond is easily formed.

As the precursor compound, one compound having a binding group and a reactive group may be used alone, or two or more compounds may be used in combination.

The precursor compound may contain one or more compounds selected from the group consisting of a carboxyl group-containing silicon compound, an amino group-containing silicon compound, and a mercapto group-containing silicon compound.

Specific examples of the carboxyl group-containing silicon compound include, for example, 3- (trimethoxysilyl) propionic acid, 3- (triethoxysilyl) propionic acid, 2-, carboxyethylphenylbis (2-methoxyethoxy) silane, N-. [3- (Trimethoxysilyl) propyl] -N'-carboxymethylethylenediamine, N- [3- (trimethoxysilyl) propyl] phthalamide, N- [3- (trimethoxysilyl) propyl] ethylenediamine-N, N' , N'-triacetic acid and the like.

Specific examples of the amino group-containing silicon compound include, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, and N- (2). -Aminoethyl) -3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldipropoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldiisopropoxysilane , N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltripropoxy Silane, N- (2-aminoethyl) -3-aminopropyltriisopropoxysilane, N- (2-aminoethyl) -3-aminoisobutyldimethylmethoxysilane, N- (2-aminoethyl) -3-aminoisobutyl Methyldimethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylsilanetriol, 3-triethoxysilyl-N- (1,3) -Dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N, N-bis [3- (trimethoxysilyl) propyl] ethylenediamine, (aminoethylaminoethyl) phenyltrimethoxysilane, (amino) Ethylaminoethyl) phenyltriethoxysilane, (aminoethylaminoethyl) phenyltripropoxysilane, (aminoethylaminoethyl) phenyltriisopropoxysilane, (aminoethylaminomethyl) phenyltrimethoxysilane, (aminoethylaminomethyl) phenyl Triethoxysilane, (aminoethylaminomethyl) phenyltripropoxysilane, (aminoethylaminomethyl) phenyltriisopropoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane, N- ( Vinylbenzyl) -2-aminoethyl-3-aminopropylmethyldimethoxylane, N-β- (N-vinylbenzylaminoethyl) -N-γ- (N-vinylbenzyl) -γ-aminopropyltrimethoxysilane, N -Β- (N-di (vinylbenzyl) aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (N-di (vinylbenzyl)) Aminoethyl) -N-γ- (N-vinylbenzyl) -γ-aminopropyltrimethoxysilane, methylbenzylaminoethylaminopropyltrimethoxysilane, dimethylbenzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltrimethoxy Silane, benzylaminoethylaminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3- (N-phenyl) aminopropyltrimethoxysilane, N, N-bis [3- (trimethoxysilyl) propyl] ethylenediamine, ( Aminoethyl Aminoethyl) Fenetilt Limethoxysilane, (Aminoethyl Aminoethyl) Fenetilt Liethoxysilane, (Aminoethyl Aminoethyl) Fenetilt Lippropoxysilane, (Aminoethyl Aminoethyl) Penetilt Liisopropoxysilane, (Aminoethyl Aminomethyl) Phenethyltrimethoxysilane, (Aminoethylaminomethyl) Phenetilthriethoxysilane, (Aminoethylaminomethyl) Fenetilt Lippropoxysilane, (Aminoethylaminomethyl) Phenetilthriisopropoxysilane, N- [2- [3- (Trimethoxy) Cyril) propylamino] ethyl] ethylenediamine, N- [2- [3- (triethoxysilyl) propylamino] ethyl] ethylenediamine, N- [2- [3- (tripropoxysilyl) propylamino] ethyl] ethylenediamine, N -[2- [3- (Triisopropoxysilyl) propylamino] ethyl] ethylenediamine and the like can be mentioned.

Specific examples of the mercapto group-containing silicon compound include, for example, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, and 2-mercaptoethyl. Trimethoxysilane, 2-mercaptoethyltriethoxysilane, 2-mercaptoethylmethyldimethoxysilane, 2-mercaptoethylmethyldiethoxysilane, 3-[ethoxybis (3,6,9,12,15-pentaoxaoctacosan-1) -Iloxy) Cyril] -1-Propylthiol and the like can be mentioned.

The thickness of the surface layer is preferably 0.5 to 50 nm, more preferably 1.0 to 30 nm. Luminescent particles having a surface layer having such a thickness can sufficiently enhance the heat stability of the nanocrystal particles.
The thickness of the surface layer can be changed by adjusting the number of atoms (chain length) of the linking structure that connects the binding group and the reactive group of the precursor compound.

The surface layer is formed by a method comprising mixing a solution containing a raw material compound for nanocrystal particles and a solution containing a precursor compound, and then condensing a reactive group liganded on the surface of the precipitated nanocrystal particles. , Can be formed.

[Hollow particles]
The luminescent particles may further include an inner space containing the nanocrystal particles and hollow particles having pores communicating with the inner space. Since the nanocrystal particles are contained inside the hollow particles, the stability of the luminescent particles with respect to oxygen gas and moisture can be further improved.

The hollow particles may have a spherical shape (true spherical shape), an elongated spherical shape (elliptical spherical shape), or a cubic shape (including a rectangular parallelepiped and a cube). Hollow particles can also be referred to as particles having a balloon structure.

One nanocrystal particle may be present in the inner space, or a plurality of nanocrystal particles may be present. Further, the inner space may be entirely occupied by one or a plurality of nanocrystal particles, or may be partially occupied.

The hollow particles may be any material as long as they can protect the nanocrystal particles. From the viewpoint of ease of synthesis, permeability, cost and the like, the hollow particles are preferably hollow silica particles, hollow alumina particles, hollow titanium oxide particles or hollow polymer particles, and are hollow silica particles or hollow alumina particles. More preferably, hollow silica particles are further preferable.

The average outer diameter of the hollow particles is not particularly limited, but is preferably 5 to 300 nm, more preferably 6 to 100 nm, further preferably 8 to 50 nm, and particularly preferably 10 to 25 nm. preferable. The average inner diameter of the hollow silica particles is also not particularly limited, but is preferably 1 to 250 nm, more preferably 2 to 100 nm, still more preferably 3 to 50 nm, and 5 to 15 nm. Is particularly preferable. Hollow particles of this size can sufficiently enhance the heat stability of the nanocrystal particles.

The size of the pores is not particularly limited, but is preferably 0.5 to 10 nm, and more preferably 1 to 5 nm. In this case, the solution containing the raw material compound of the nanocrystal particles can be smoothly and surely filled in the inner space.

Commercially available products can also be used for the hollow silica particles. Examples of such commercially available products include "SiliNax (registered trademark) SP-PN (b)" manufactured by Nittetsu Mining Co., Ltd. The hollow particles are preferably hollow silica particles from the viewpoint of luminescence and dispersion characteristics in ink and the like, in addition to stabilizing the semiconductor nanocrystal particles.

For example, by impregnating a hollow particle with a solution containing a raw material compound of the nanocrystal particle and drying it, the nanocrystal particle is precipitated in the inner space of the hollow particle, so that the nanocrystal particle is formed in the inner space of the hollow particle. Be housed.

[Polymer layer]
The luminescent particles may further comprise a polymer layer containing a hydrophobic polymer. The polymer layer may be located on the outermost layer of the luminescent particles, including the nanocrystal particles. For example, if the luminescent particles have a surface layer, the polymer layer may be a layer that covers at least a portion of the surface layer. When the luminescent particles contain hollow silica, the polymer layer may be a layer that covers at least a portion of the hollow silica. When the nanocrystal particles have a polymer layer, high stability to oxygen and moisture can be imparted to the luminescent particles. Further, when the ink composition is prepared using the luminescent particles having a polymer layer, the dispersion stability of the luminescent particles can be improved. When the polymer layer is provided, the luminescent particles are less likely to aggregate when the ink composition is prepared, and the emission characteristics are less likely to be deteriorated due to the aggregation.

The polymer layer is formed by coating the surface of the particles to be coated (hereinafter, also referred to as "mother particles") with a hydrophobic polymer. The polymer layer is formed by polymerizing the monomer (M) in the presence of mother particles, a non-aqueous solvent and the polymer (P).

[Non-aqueous solvent]
The non-aqueous solvent is preferably an organic solvent capable of dissolving the hydrophobic polymer, and more preferably if the mother particles can be uniformly dispersed. By using such a non-aqueous solvent, the hydrophobic polymer can be very easily adsorbed on the mother particles to coat the polymer layer. Further, preferably, the non-aqueous solvent is a low dielectric constant solvent. By using a low dielectric constant solvent, the hydrophobic polymer can be strongly adsorbed on the surface of the mother particles and the polymer layer can be coated only by mixing the hydrophobic polymer and the mother particles in the non-aqueous solvent.
The polymer layer thus obtained is difficult to be removed from the mother particles even if the luminescent particles are washed with a solvent. Further, the lower the dielectric constant of the non-aqueous solvent, the more preferable. Specifically, the dielectric constant of the non-aqueous solvent is preferably 10 or less, more preferably 6 or less, and particularly preferably 5 or less. Preferred non-aqueous solvents are an aliphatic hydrocarbon solvent and an alicyclic hydrocarbon solvent, and an organic solvent containing at least one of them is preferable.

Examples of the aliphatic hydrocarbon solvent or the alicyclic hydrocarbon solvent include n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane and the like.
Further, as long as the effect of the present invention is not impaired, a mixed solvent in which at least one of the aliphatic hydrocarbon solvent and the alicyclic hydrocarbon solvent is mixed with another organic solvent may be used as the non-aqueous solvent. good. Examples of such other organic solvents include aromatic hydrocarbon solvents such as toluene and xylene; ester solvents such as methyl acetate, ethyl acetate, -n-butyl acetate and amyl acetate; acetone, methyl ethyl ketone and methyl isobutyl. Ketone solvents such as ketones, methylamylketones and cyclohexanones; alcoholic solvents such as methanol, ethanol, n-propanol, i-propanol, n-butanol and the like can be mentioned.
When used as a mixed solvent, the amount of at least one of the aliphatic hydrocarbon solvent and the alicyclic hydrocarbon solvent is preferably 50% by mass or more, more preferably 60% by mass or more. preferable.

[Polymer (P)]
The polymer (P) is a polymer containing a polymerizable unsaturated group soluble in a non-aqueous solvent. The polymer (P) is polymerizable unsaturated, mainly composed of an alkyl (meth) acrylate (A) having an alkyl group having 4 or more carbon atoms or a fluorine-containing compound (B, C) having a polymerizable unsaturated group. A polymer in which a polymerizable unsaturated group is introduced into a monomer copolymer, an alkyl (meth) acrylate (A) having an alkyl group having 4 or more carbon atoms, or a fluorine-containing compound having a polymerizable unsaturated group ( A macromonomer made of a copolymer of a polymerizable unsaturated monomer containing B and C) as a main component can be used.

Examples of the alkyl (meth) acrylate (A) include n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate. , Isodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl Examples include (meth) acrylate. Here, in the present specification, "(meth) acrylate" means both methacrylate and acrylate. The same applies to the expression "(meth) acryloyl".

Examples of the fluorine-containing compound (B) having a polymerizable unsaturated group include methacrylates represented by the following formulas (B1-1) to (B1-7) and the following formulas (B1-8) to (B1-15). Examples include acrylates and the like. It should be noted that these compounds may be used alone or in combination of two or more.

Examples of the fluorine-containing compound (C) having a polymerizable unsaturated group include a poly (perfluoroalkylene ether) chain and a compound having a polymerizable unsaturated group at both ends thereof.
Specific examples of the fluorine-containing compound (C) include compounds represented by the following formulas (C-1) to (C-13). In addition, "-PFPE-" in the following formulas (C-1) to (C-13) is a poly (perfluoroalkylene ether) chain.

Among them, the fluorine-containing compound (C) is represented by the above formulas (C-1), (C-2), (C-5) or (C-6) from the viewpoint of easy industrial production. Acryloyl groups are used at both ends of the poly (perfluoroalkylene ether) chain represented by the above formula (C-1) because the compound is preferable and the polymer (P) that is easily entangled with the surface of the mother particles can be synthesized. , Or a compound having methacryloyl groups at both ends of the poly (perfluoroalkylene ether) chain represented by the above formula (C-2) is more preferable.

Further, as the polymer (P), as the compound other than the above-mentioned alkyl (meth) acrylate (A) and the fluorine-containing compound (B, C), for example, styrene, α-methylstyrene, pt-butylstyrene, vinyl. Aromatic vinyl compounds such as toluene; (meth) acrylates such as benzyl (meth) acrylate, dimethylamino (meth) acrylate, diethylamino (meth) acrylate, dibromopropyl (meth) acrylate, tribromophenyl (meth) acrylate. Systems compounds: Diester compounds of unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid and monovalent alcohols, vinyl benzoate, vinyl esters such as "Beova" (vinyl ester manufactured by Shell, Netherlands). Examples include system compounds.
These compounds are preferably used as a random copolymer with an alkyl (meth) acrylate (A) or a fluorine-containing compound (B, C). Thereby, the solubility of the obtained polymer (P) in a non-aqueous solvent can be sufficiently enhanced.

As the compound that can be used as the polymer (P), one type may be used alone, or two or more types may be used in combination. Among them, the alkyl (meth) acrylate (A) having a linear or branched alkyl group having 4 to 12 carbon atoms such as n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl methacrylate is used. It is preferable to use it.

After obtaining a copolymer of the compound by polymerizing these compounds by a conventional method, a polymer (P) can be obtained by introducing a polymerizable unsaturated group into the copolymer.

As a method for introducing a polymerizable unsaturated group, for example, a carboxylic acid group-containing polymerizable monomer such as acrylic acid or methacrylic acid, or an amino group such as dimethylaminoethyl methacrylate or dimethylaminopropylacrylamide can be used as a copolymerization component in advance. A copolymer having a carboxylic acid group or an amino group is obtained by blending and copolymerizing the containing polymerizable monomer, and then the carboxylic acid group or the amino group is combined with a glycidyl group such as glycidyl methacrylate and a polymerizable unsaturated group. Examples thereof include a method of reacting a monomer having.

[Monomer (M)]
The monomer (M) is a polymerizable unsaturated monomer that is soluble in a non-aqueous solvent and becomes insoluble or sparingly soluble after polymerization. Examples of the monomer (M) include vinyl-based monomers having no reactive polar group (functional group), amide bond-containing vinyl-based monomers, (meth) acryloyloxyalkyl phosphates, and (meth) acrylic. Loyloxyalkyl phosphites, phosphorus atom-containing vinyl-based monomers, hydroxyl group-containing polymerizable unsaturated monomers, dialkylaminoalkyl (meth) acrylates, epoxy group-containing polymerizable unsaturated monomers, isocyanate group-containing Examples thereof include α, β-ethylenic unsaturated monomers, alkoxysilyl group-containing polymerizable unsaturated monomers, and carboxyl group-containing α, β-ethylenically unsaturated monomers.

Specific examples of vinyl-based monomers having no reactive polar group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and i-propyl (meth) acrylate. Examples thereof include (meth) acrylates, (meth) acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl fluoride, olefins such as vinylidene fluoride and the like.
Specific examples of the amide bond-containing vinyl-based monomers include (meth) acrylamide, dimethyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N-octyl (meth) acrylamide, diacetone acrylamide, and dimethylamino. Examples thereof include propylacrylamide, alkoxylated N-methylolated (meth) acrylamides and the like.

Specific examples of the (meth) acryloyloxyalkyl phosphates include dialkyl [(meth) acryloyloxyalkyl] phosphates, (meth) acryloyloxyalkyl acid phosphates and the like.
Specific examples of (meth) acryloyloxyalkyl phosphites include dialkyl [(meth) acryloyloxyalkyl] phosphites, (meth) acryloyloxyalkyl acid phosphites, and the like.
Specific examples of the phosphorus atom-containing vinyl-based monomers include alkylene oxide adducts of the above-mentioned (meth) acryloyloxyalkyl acid phosphates or (meth) acryloyloxyalkyl acid phosphites, glycidyl (meth) acrylate, and the like. Examples thereof include ester compounds of an epoxy group-containing vinyl-based monomer such as methylglycidyl (meth) acrylate with phosphoric acid, phosphite or acidic esters thereof, 3-chloro-2-acid phosphoxypropyl (meth) acrylate and the like. Be done.

Specific examples of hydroxyl group-containing polymerizable unsaturated monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (. Meta) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl Hydroxyalkyl esters of polymerizable unsaturated carboxylic acids such as monobutyl fumarate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate or adducts of these with ε-caprolactone; (meth) acrylic acid. , Crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and other unsaturated mono- or dicarboxylic acids, polymerizable unsaturated carboxylic acids such as monoesters of dicarboxylic acid and monovalent alcohol; Hydroxyalkyl esters of saturated carboxylic acids and anhydrides of polycarboxylic acids (maleic acid, succinic acid, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, hensentricarboxylic acid, benzenetetracarboxylic acid, "hymic acid", tetra Monoglycidyl esters of various unsaturated carboxylic acids such as additives with chlorphthalic acid, dodecynyl succinic acid, etc. and monovalent carboxylic acids (palm oil fatty acid glycidyl ester, octyl acid glycidyl ester, etc.), butyl glycidyl ether, ethylene oxide, Additives with monoepoxy compounds such as propylene oxide or adducts with these with ε-caprolactone; hydroxyvinyl ethers and the like can be mentioned.

Specific examples of the dialkylaminoalkyl (meth) acrylates include dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate.
Specific examples of the epoxy group-containing polymerizable unsaturated monomer include a polymerizable unsaturated carboxylic acid, an equimolar adduct of a hydroxyl group-containing vinyl monomer and the anhydride of the polycarboxylic acid (mono-2- (mono-2- (). Epoxy group-containing polymerization obtained by adding various polyepoxy compounds having at least two epoxy groups in one molecule to various unsaturated carboxylic acids such as meta) acryloyloxymonoethylphthalate) at an equimolar ratio. Examples thereof include sex compounds, glycidyl (meth) acrylate, (β-methyl) glucidyl (meth) acrylate, (meth) allyl glucidyl ether and the like.

Specific examples of the isocyanate group-containing α, β-ethylenically unsaturated monomers include, for example, an equimolar adduct of 2-hydroxyethyl (meth) acrylate and hexamethylene diisocyanate, and isocyanate ethyl (meth) acrylate. Examples thereof include monomers having an isocyanate group and a vinyl group.
Specific examples of the alkoxysilyl group-containing polymerizable unsaturated monomers include silicone-based monomers such as vinylethoxysilane, α-methacryloxypropyltrimethoxysilane, and trimethylsiloxyethyl (meth) acrylate. Be done.

Specific examples of the carboxyl group-containing α, β-ethylenic unsaturated monomers include unsaturated mono- or dicarboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid. Α, β-Ethenyl unsaturated carboxylic acids such as monoesters of acids, dicarboxylic acids and monovalent alcohols; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl ( Meta) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl Α, β-Unsaturated carboxylic acid hydroalkyl esters such as fumarate, mono-2-hydroxyethyl-monobutyl fumarate, polyethylene glycol mono (meth) acrylate and maleic acid, succinic acid, phthalic acid, hexahydrophthal Examples thereof include additions of polycarboxylic acids such as acids, tetrahydrophthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, "hymic acid", tetrachlorophthalic acid and dodecynylsuccinic acid with an anhydride.

Among them, the monomer (M) is preferably an alkyl (meth) acrylate having an alkyl group having 3 or less carbon atoms, such as methyl (meth) acrylate and ethyl (meth) acrylate.

The polymer layer is formed by polymerizing the monomer (M) in the presence of mother particles, a non-aqueous solvent and the polymer (P).
It is preferable that the mother particles and the polymer (P) are mixed before the polymerization is carried out. For mixing, for example, a homogenizer, a disper, a bead mill, a paint shaker, a kneader, a roll mill, a ball mill, an attritor, a sand mill and the like can be used.
The form of the mother particles used when forming the polymer layer is not particularly limited, and may be any of slurry, wet cake, powder and the like.
After mixing the mother particle and the polymer (P), the monomer (M) and the polymerization initiator described later are further mixed and polymerized to obtain the polymer (P) and the monomer (M). A polymer layer composed of the polymer is formed. As a result, luminescent particles are obtained.

At this time, the number average molecular weight of the polymer (P) is preferably 1,000 to 500,000, more preferably 2,000 to 200,000, and more preferably 3,000 to 100,000. Is even more preferable. By using the polymer (P) having a molecular weight in such a range, the surface of the mother particles can be satisfactorily coated with the polymer layer.
The amount of the polymer (P) used is appropriately set according to the intended purpose and is not particularly limited, but is usually 0.5 to 50 parts by mass with respect to 100 parts by mass of the mother particles. It is preferably 1 to 40 parts by mass, more preferably 2 to 35 parts by mass.
Further, the amount of the monomer (M) used is also appropriately set according to the purpose and is not particularly limited, but is usually 0.5 to 40 parts by mass with respect to 100 parts by mass of the mother particle. It is preferably 1 to 35 parts by mass, more preferably 2 to 30 parts by mass.

The amount of the hydrophobic polymer finally covering the surface of the mother particles is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass with respect to 100 parts by mass of the mother particles. It is more preferably 3 to 40 parts by mass.
In this case, the amount of the monomer (M) is usually preferably 10 to 100 parts by mass, more preferably 30 to 90 parts by mass with respect to 100 parts by mass of the polymer (P). , 50-80 parts by mass is more preferable.
The thickness of the polymer layer is preferably 0.5 to 100 nm, more preferably 0.7 to 50 nm, and even more preferably 1 to 30 nm. If the thickness of the polymer layer is less than 0.5 nm, dispersion stability is often not obtained. If the thickness of the polymer layer exceeds 100 nm, it is often difficult to contain the mother particles at a high concentration. By coating the mother particles with a polymer layer having such a thickness, the stability of the luminescent particles with respect to oxygen and moisture can be further improved.

The polymerization of the monomer (M) in the presence of the mother particles, the non-aqueous solvent and the polymer (P) can be carried out by a known polymerization method, but is preferably carried out in the presence of a polymerization initiator.
Examples of such polymerization initiators include dimethyl-2,2-azobis (2-methylpropionate), azobisisobutyronitrile (AIBN), 2,2-azobis (2-methylbutyronitrile), and benzoyl. Examples thereof include peroxide, t-butyl perbenzoate, t-butyl-2-ethylhexanoate, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydroperoxide and the like. These polymerization initiators may be used alone or in combination of two or more.
The polymerization initiator, which is sparingly soluble in a non-aqueous solvent, is preferably added to the mixture containing the mother particles and the polymer (P) in a state of being dissolved in the monomer (M).

Further, the monomer (M) or the monomer (M) in which the polymerization initiator is dissolved may be added to the mixed solution having reached the polymerization temperature by a dropping method and polymerized, but at room temperature before the temperature rise. It is stable and preferable to add it to the mixed solution, mix it sufficiently, and then raise the temperature to polymerize it.
The polymerization temperature is preferably in the range of 60 to 130 ° C, more preferably in the range of 70 to 100 ° C. If the monomer (M) is polymerized at such a polymerization temperature, morphological changes (for example, alteration, crystal growth, etc.) of the nanocrystal particles can be suitably prevented.
After the polymerization of the monomer (M), the polymer not adsorbed on the surface of the mother particles is removed to obtain luminescent particles. Examples of the method for removing the polymer that has not been adsorbed include centrifugal sedimentation and ultrafiltration. In centrifugal sedimentation, the dispersion liquid containing the mother particles and the polymer that has not been adsorbed is rotated at high speed, the mother particles in the dispersion liquid are settled, and the polymer that has not been adsorbed is separated. In ultrafiltration, a dispersion containing the mother particles and the non-adsorbed polymer is diluted with an appropriate solvent, and the diluted solution is passed through a filtration membrane having an appropriate pore size to separate the unadsorbed polymer and the mother particles. To separate. As described above, luminescent particles having a polymer layer can be obtained. The luminescent particles may be stored in a state of being dispersed in a dispersion medium or a photopolymerizable compound (that is, as a dispersion liquid), or the dispersion medium may be removed and stored as a powder (aggregate of luminescent particles alone). You may.

The content of the luminescent particles in the ink composition is preferably 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and is 20% by mass or less, 15% by mass or less, or 10% by mass. It is less than mass%. By setting the content of the luminescent particles in the above range, when the ink composition is ejected by the inkjet printing method, the ejection stability can be further improved. In addition, the luminescent particles are less likely to aggregate with each other, and the external quantum efficiency of the obtained light emitting layer (light conversion layer) can be increased.

The ink composition may contain two or more of red luminescent particles, green luminescent particles, and blue luminescent particles as the luminescent particles, but may contain only one of these particles. Is more preferable. When the ink composition contains red luminescent particles, the content of the green luminescent particles and the content of the blue luminescent particles are preferably 5% by mass or less, more preferably, based on the total mass of the luminescent particles. Is 0% by mass. When the ink composition contains green luminescent particles, the content of the red luminescent particles and the content of the blue luminescent particles are preferably 5% by mass or less, more preferably, based on the total mass of the luminescent particles. Is 0% by mass.

<< Photopolymerizable compound >>
The photopolymerizable compound is a compound having a polymerizable functional group and polymerizing by irradiation with light. The photopolymerizable compound is preferably a photoradical polymerizable compound that polymerizes by irradiation with light. The photopolymerizable compound may be a photopolymerizable monomer or oligomer. These are used with photopolymerization initiators. The ink composition may contain one kind of photopolymerizable compound, two or more kinds, and preferably two or more kinds.

Examples of the photopolymerizable compound include a monomer having an ethylenically unsaturated group (hereinafter, also referred to as “ethylenically unsaturated monomer”) and the like. Here, the ethylenically unsaturated monomer means a monomer having an ethylenically unsaturated bond (carbon-carbon double bond). Examples of the ethylenically unsaturated monomer include a monomer having an ethylenically unsaturated group such as a vinyl group, a vinylene group, a vinylidene group, a (meth) acryloyl group, and a (meth) acrylamide group. Monomers having these groups may be referred to as "vinyl monomers".

The number of ethylenically unsaturated bonds (for example, the number of ethylenically unsaturated groups) in the ethylenically unsaturated monomer is, for example, 1 to 3. One type of ethylenically unsaturated monomer may be used alone, or a plurality of types may be used in combination. The photopolymerizable compound may contain a monomer having one ethylenically unsaturated group (monofunctional monomer) and a monomer having two or more ethylenically unsaturated groups (polyfunctional monomer), and may be a monofunctional monomer. , At least one selected from the group consisting of a monomer having two ethylenically unsaturated groups (bifunctional monomer) and a monomer having three ethylenically unsaturated groups (trifunctional monomer) may be contained. The photopolymerizable compound may contain two or more monofunctional monomers and may contain two or more monofunctional monomers and one or two polyfunctional monomers. Two monofunctional monomers. And at least one selected from the group consisting of bifunctional monomers and trifunctional monomers.

The ethylenically unsaturated group may be a vinyl group, a vinylene group, a vinylidene group, a (meth) acryloyl group or the like, and is preferably a (meth) acryloyl group. However, since the monomer having a (meth) acrylamide group used in the ink composition disclosed in Patent Document 1 is water-soluble, it is easy to dissolve nanocrystal particles made of metal halide and has remarkable light emission characteristics over time. It is not preferable to use it in the ink composition of the present invention because it reduces the amount of ink. In addition, in this specification, "(meth) acryloyl group" means "acryloyl group" and "methacryloyl group". The same applies to the expression "(meth) acrylate". The "(meth) acrylamide group" means an "acrylamide group" and a "methacrylamide group".

Examples of the radically polymerizable compound include a (meth) acrylate compound which is a compound having a (meth) acryloyl group. The (meth) acrylate compound may be a monofunctional (meth) acrylate having one (meth) acryloyl group, or may be a polyfunctional (meth) acrylate having a plurality of (meth) acryloyl groups. Photopolymerizable compounds are selected from the viewpoints of excellent fluidity when preparing an ink composition, excellent ejection stability, and suppressing deterioration of smoothness due to curing shrinkage during production of a luminescent particle coating film. , Monofunctional (meth) acrylate and polyfunctional (meth) acrylate are preferably contained.

Examples of the monofunctional (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and octyl. (Meta) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxy Ethyl (meth) acrylate, nonylphenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, Dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, benzyl (Meta) acrylate, phenylbenzyl (meth) acrylate, monosuccinate (2-acryloyloxyethyl), N- [2- (acryloyloxy) ethyl] phthalimide, N- [2- (acryloyloxy) ethyl] tetrahydrophthalimide, etc. Can be mentioned.

The polyfunctional (meth) acrylate may be a bifunctional (meth) acrylate, a trifunctional (meth) acrylate, a tetrafunctional (meth) acrylate, a pentafunctional (meth) acrylate, a hexafunctional (meth) acrylate, or the like, and may be, for example. A di (meth) acrylate in which two hydroxyl groups of a diol compound are substituted with a (meth) acryloyloxy group, and a di or tri (meth) acrylate in which two or three hydroxyl groups of a triol compound are substituted with a (meth) acryloyloxy group. And so on.

Specific examples of the bifunctional (meth) acrylate include 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,5-pentanediol di (meth) acrylate. 3-Methyl-1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1 , 9-Nonandiol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di Two hydroxyl groups: (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentylglycol hydroxypivalic acid ester diacrylate, and tris (2-hydroxyethyl) isocyanurate. Di (meth) acrylate substituted with (meth) acryloyloxy group has two hydroxyl groups of (meth) acryloyloxy in a diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol. Di (meth) acrylate substituted with a group Two hydroxyl groups of a diol obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A are substituted with a (meth) acryloyloxy group. ) Acrylate A di (meth) acrylate in which two hydroxyl groups of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylol propane are substituted with a (meth) acryloyloxy group. Examples thereof include di (meth) acrylate in which two hydroxyl groups of a diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to bisphenol A are substituted with a (meth) acryloyloxy group.

Specific examples of the trifunctional (meth) acrylate include, for example, trimethylolpropane tri (meth) acrylate, glycerin triacrylate, pentaerythritol tri (meth) acrylate, 1 mol of trimethylolpropane and 3 mol or more of ethylene oxide or propylene. Examples thereof include tri (meth) acrylate in which the three hydroxyl groups of triol obtained by adding an oxide are substituted with a (meth) acryloyloxy group.
Specific examples of the tetrafunctional (meth) acrylate include pentaerythritol tetra (meth) acrylate and the like.
Specific examples of the pentafunctional (meth) acrylate include dipentaerythritol penta (meth) acrylate and the like.
Specific examples of the hexafunctional (meth) acrylate include dipentaerythritol hexa (meth) acrylate and the like.

The polyfunctional (meth) acrylate may be a poly (meth) acrylate in which a plurality of hydroxyl groups of dipentaerythritol such as dipentaerythritol hexa (meth) acrylate are substituted with (meth) acryloyloxy groups.
The (meth) acrylate compound may be an ethylene oxide-modified phosphoric acid (meth) acrylate, an ethylene oxide-modified alkyl phosphoric acid (meth) acrylate, or the like, which has a phosphoric acid group.

In the ink composition, when the curable component is composed of only the photopolymerizable compound or the main component thereof, the photopolymerizable compound as described above has two or more polymerizable functional groups in one molecule. It is more preferable to use a polyfunctional photopolymerizable compound having two or more functionalities as an essential component because the durability (strength, heat resistance, etc.) of the cured product can be further enhanced.

Further, it is possible to suppress the deterioration of the smoothness of the coating film due to the viewpoint of excellent viscosity stability when the ink composition is prepared, the viewpoint of excellent ejection stability, and the curing shrinkage during the production of the luminescent particle coating film. From the viewpoint, it is preferable to use a monofunctional (meth) acrylate and a polyfunctional (meth) acrylate in combination.

The molecular weight of the photopolymerizable compound is, for example, 50 or more, and may be 100 or more or 150 or more. The molecular weight of the photopolymerizable compound is, for example, 500 or less, and may be 400 or less or 300 or less. From the viewpoint of easily achieving both the viscosity of the inkjet ink and the volatility of the ink after ejection, it is preferably 50 to 500, and more preferably 100 to 400.

From the viewpoint of reducing the stickiness (tack) of the surface of the cured product of the ink composition, it is preferable to use a radically polymerizable compound having a cyclic structure as the photopolymerizable compound. The cyclic structure may be an aromatic ring structure or a non-aromatic ring structure. The number of cyclic structures (total number of aromatic rings and non-aromatic rings) is 1 or 2 or more, but preferably 3 or less. The number of carbon atoms constituting the cyclic structure is, for example, 4 or more, and preferably 5 or more or 6 or more. The number of carbon atoms is, for example, 20 or less, preferably 18 or less.

The aromatic ring structure is preferably a structure having an aromatic ring having 6 to 18 carbon atoms. Examples of the aromatic ring having 6 to 18 carbon atoms include a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring and the like. The aromatic ring structure may be a structure having an aromatic heterocycle. Examples of the aromatic heterocycle include a furan ring, a pyrrole ring, a pyran ring, a pyridine ring and the like. The number of aromatic rings may be 1 or 2 or more, but is preferably 3 or less. The organic group may have a structure (for example, a biphenyl structure) in which two or more aromatic rings are bonded by a single bond.

The non-aromatic ring structure is preferably a structure having, for example, an alicyclic having 5 to 20 carbon atoms. Examples of the alicyclic ring having 5 to 20 carbon atoms include a cycloalkane ring such as a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, and a cyclooctane ring, a cycloalkene ring such as a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, and a cyclooctene ring. Can be mentioned. The alicyclic ring may be a fused ring such as a bicycloundecane ring, a decahydronaphthalene ring, a norbornene ring, a norbornadiene ring, or an isobornyl ring. The non-aromatic ring structure may be a structure having a non-aromatic heterocycle. Examples of the non-aromatic heterocycle include a tetrahydrofuran ring, a pyrrolidine ring, a tetrahydropyran ring, a piperidine ring and the like.

The radically polymerizable compound having a cyclic structure is preferably a monofunctional or polyfunctional (meth) acrylate having a cyclic structure, and more preferably a monofunctional (meth) acrylate having a cyclic structure. Specifically, phenoxyethyl (meth) acrylate, phenoxybenzyl (meth) acrylate, biphenyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate and the like are available. It is preferably used.

The content of the radically polymerizable compound having a cyclic structure is from the viewpoint of easily suppressing the stickiness (tack) of the surface of the ink composition, and from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink and easily obtaining excellent ejection properties. Based on the total mass of the photopolymerizable compound in the ink composition, it is preferably 3 to 85% by mass, more preferably 5 to 65% by mass, and further preferably 10 to 45% by mass. It is preferably 15 to 35% by mass, and particularly preferably 15 to 35% by mass.

From the viewpoint of easily obtaining excellent ejection properties, it is preferable to use a radically polymerizable compound having a linear structure having 3 or more carbon atoms as the ink composition, and having a linear structure having 4 or more carbon atoms. It is more preferable to use a radically polymerizable compound. The linear structure represents a hydrocarbon chain having 3 or more carbon atoms. In the radically polymerizable compound having a linear structure, a hydrogen atom directly connected to a carbon atom constituting the linear structure may be substituted with a methyl group or an ethyl group, but the number of substitutions may be 3 or less. preferable. The radically polymerizable compound having a linear structure having 4 or more carbon atoms preferably has a structure in which atoms other than hydrogen atoms are connected without branching, and other than carbon atoms and hydrogen atoms. In addition, it may have a hetero atom such as an oxygen atom. That is, the linear structure is not limited to a structure in which three or more carbon atoms are linearly continuous, and is a structure in which three or more carbon atoms are linearly connected via a heteroatom such as an oxygen atom. May be good. The linear structure may have unsaturated bonds, but preferably consists only of saturated bonds. The number of carbon atoms constituting the linear structure is preferably 5 or more, more preferably 6 or more, and further preferably 7 or more. The number of carbon atoms constituting the linear structure is preferably 25 or less, more preferably 20 or less, still more preferably 15 or less. In addition, radical polymerization having a linear structure in which the total number of carbon atoms is 3 or more (the carbon atom of the methyl group or the ethyl group in which the hydrogen atom directly connected to the carbon atom forming the linear structure is substituted is not included in the number). The sex compound preferably does not have a cyclic structure from the viewpoint of ejection property.

The linear structure is preferably, for example, a structure having a linear alkyl group having 4 or more carbon atoms. Examples of the linear alkyl group having 4 or more carbon atoms include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group and a pentadecyl group. Can be mentioned. As the radically polymerizable compound having such a structure, an alkyl (meth) acrylate in which the linear alkyl group is directly bonded to the (meth) acryloyloxy group is preferably used.

The linear structure is preferably, for example, a structure having a linear alkylene group having 4 or more carbon atoms. Examples of the linear alkylene group having 4 or more carbon atoms include a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, a dodecylene group, a tridecylene group, a tetradecylene group and a pentadecylene group. Can be mentioned. As the radically polymerizable compound having such a structure, an alkylene glycol di (meth) acrylate in which two (meth) acryloyloxy groups are bonded by the above-mentioned linear alkylene group is preferably used.

The linear structure is preferably, for example, a structure in which a linear alkyl group and one or more linear alkylene groups are bonded via an oxygen atom (a structure having an alkyl (poly) oxyalkylene group). The number of linear alkylene groups is 2 or more, preferably 6 or less. When the number of linear alkylene groups is 2 or more, the 2 or more alkylene groups may be the same or different. The number of carbon atoms of the linear alkyl group and the linear alkylene group may be 1 or more, may be 2 or more or 3 or more, but is preferably 4 or less. Examples of the linear alkyl group include the above-mentioned linear alkyl group having 4 or more carbon atoms, as well as a methyl group, an ethyl group and a propyl group. Examples of the linear alkylene group include the above-mentioned linear alkylene group having 4 or more carbon atoms, a methylene group, an ethylene group and a propylene group. As the radically polymerizable compound having such a structure, an alkyl (poly) oxyalkylene (meth) acrylate in which the above-mentioned alkyl (poly) oxyalkylene group is directly bonded to the (meth) acryloyloxy group is preferably used.

The content of the radically polymerizable compound having a linear structure having 3 or more carbon atoms is excellent in the viewpoint that an appropriate viscosity can be easily obtained as an ink jet ink, an excellent ejection property can be easily obtained, and the curability of the ink composition is excellent. From the viewpoint, from the viewpoint of easily suppressing the stickiness (tack) of the surface of the ink composition, it is preferably 10 to 90% by mass, preferably 15 to 80% by mass, based on the total mass of the photopolymerizable compound in the ink composition. It is more preferably%, and particularly preferably 20 to 70% by mass.

As the photopolymerizable compound, it is preferable to use two or more kinds of radically polymerizable compounds from the viewpoint of excellent surface uniformity of the pixel portion, and the above-mentioned radically polymerizable compound having a cyclic structure and the above-mentioned number of carbon atoms are used. It is more preferable to use in combination with a radically polymerizable compound having a linear structure of 3 or more. When the amount of nanoparticles containing luminescent nanocrystals is increased in order to improve the external quantum efficiency, the uniformity of the surface of the pixel portion may decrease. Even in such a case, the above-mentioned light According to the combination of the polymerizable compounds, there is a tendency to obtain a pixel portion having excellent surface uniformity.

The content of the photopolymerizable compound contained in the ink composition is from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, from the viewpoint that the curability of the ink composition is good, and the pixel portion (curing of the ink composition). 70 to 95% by mass based on the total mass of the ink composition from the viewpoint of improving the solvent resistance and abrasion resistance of the product) and obtaining better optical characteristics (for example, external quantum efficiency). It is preferably 75 to 94% by mass, and even more preferably 80 to 93% by mass.

<< Photopolymerization Initiator >>
The photopolymerization initiator is, for example, a photoradical polymerization initiator or a photocationic polymerization initiator. The photopolymerization initiator may contain at least one selected from the group consisting of an alkylphenone compound, an acylphosphine oxide compound and an oxime ester compound.

Examples of the alkylphenone compound include a compound represented by the formula (b-1).

(In the formula, R ^1a represents a group selected from the following formulas (R ^1a -1) to (R ^1a -6), and R ^2a , R ^2b and R ^2c independently represent the following formula (R). ^2-1 ) -Represents a group selected from the formula (R ^2-8 ).)

Specific examples of the compound represented by the above formula (b-1) may be compounds represented by the following formulas (b-1-1) to (b-1-7), and may be compounds represented by the following formulas (b-1-7). The compound represented by 1-1) or the formula (b-1-7) is preferable.

Examples of the acylphosphine oxide compound include a compound represented by the formula (b-2).

(In the formula, R ²⁴ represents an alkyl group, an aryl group or a heterocyclic group, and R ²⁵ and R ²⁶ each independently represent an alkyl group, an aryl group, a heterocyclic group or an alkanoyl group. May be substituted with an alkyl group, a hydroxyl group, a carboxyl group, a sulfon group, an aryl group, an alkoxy group, or an arylthio group.)

As specific examples of the compound represented by the above formula (b-2), the compounds represented by the following formulas (b-2-1) to (b-2-5) are preferable, and the following formula (b-2) is preferable. A compound represented by -1) or the formula (b-2-5) is more preferable.

Examples of the oxime ester compound include compounds represented by the following formula (b-3-1) or formula (b-3-2).

(In the formula, R ²⁷ to R ³¹ each independently represent a hydrogen atom, a cyclic, linear or branched alkyl group having 1 to 12 carbon atoms, or a phenyl group, and each alkyl group and phenyl group. May be substituted with a substituent selected from the group consisting of a halogen atom, an alkoxyl group having ¹ to ⁶ carbon atoms and a phenyl group, where X1 represents an oxygen atom or a nitrogen atom and X2 is oxygen. It represents an atom or NR, and R represents an alkyl group having 1 to 6 carbon atoms.)

Specific examples of the compounds represented by the above formulas (b-3-1) and (b-3-2) include the following formulas (b-3-1-1) to (b-3-1-2). ) And the compounds represented by the following formulas (b-3-2-1) to (b-3--2-2) are preferable, and the following formulas (b-3-1-1) and (b-3-2) are preferable. A compound represented by -1) or the formula (b-3-2-2) is more preferable.

As the photopolymerization initiator, one type may be used alone, or two or more types may be mixed and used.

As the photopolymerization initiator, a compound having an ultraviolet absorption band corresponding to the ultraviolet wavelength region used for curing is used. For example, in the case of UVB (300 to 350 nm), Omnirad 907, etc. can be used, and in the case of UVA (350 to 400 nm), Omnirad TPO-H and the like can be used. For example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (compound represented by the formula (b-2-1)), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane- From 1-one (compound represented by formula (b-1-1)) and 2-benzyl-2-dimethylamino-4-morpholinobtyrophenone (compound represented by formula (b-1-3)) It is preferable to use at least one compound selected from the above group. Furthermore, 2,4,6-trimethylbenzoyldiphenylphosphine oxide can suppress yellowing of the coating film by having a photobleaching property in which absorption in the long wavelength region shifts to the short wavelength side due to cleavage after light irradiation. More preferred.

The content of the photopolymerization initiator may be 2% by mass or more based on the total mass of the ink composition. The content of the photopolymerization initiator may be 10% by mass or less, 8% by mass or less, 6% by mass or less, and 5% by mass or less from the viewpoint that the ink composition is less likely to be deteriorated. When the content of the photopolymerization initiator is 2% by mass or more, the light emission characteristics when the photoconversion layer is formed become even more excellent. When the content of the photopolymerization initiator is 10% by mass or less, the curability of the ink becomes even better while keeping the viscosity of the ink low.

When dissolving the photopolymerization initiator in the ink composition, it is preferable to dissolve it in the photopolymerizable compound in advance before use. In order to dissolve the photopolymerizable compound, it is preferable to uniformly dissolve the photopolymerizable compound by adding a photopolymerization initiator while stirring so that the reaction due to heat is not started.
The dissolution temperature of the photopolymerization initiator may be appropriately adjusted in consideration of the solubility of the photopolymerization initiator used in the photopolymerizable compound and the thermal polymerizable property of the photopolymerizable compound, but the polymerization of the photopolymerizable compound may be appropriately adjusted. The temperature is preferably 10 to 50 ° C., more preferably 10 to 40 ° C., and even more preferably 10 to 30 ° C. from the viewpoint of not starting the polymerization.

<< Photosensitizer >>
The ink composition can improve the curability of the coating film by containing a photosensitizer. The photosensitizer used is equal to or higher than the excited triplet energy of the photopolymerization initiator. The photosensitizer has the following general formula (1):

[In formula (2), R ² and R ³ independently represent an alkyl group, a hydroxy group, a dialkylamino group, and a phenyl group, n and o each independently represent an integer of 0 to 5, and n is 2. When it is an integer of ~ 5, a plurality of existing R ^2s may be the same or different from each other, and when o is an integer of 2 to 5, a plurality of existing R ^3s may be the same or different from each other. May be. ]
It is a benzophenone compound represented by.

In the thioxanthone compound, examples of the alkyl group having 2 to 3 carbon atoms as R ¹ include an ethyl group and an isopropyl group. Examples of the alkoxycarbonyl group as R ¹ include an ethoxycarbonyl group and a methoxycarbonyl group. m may be 1 to 2, and may be 1.

The thioxanthone compound may be, for example, a compound represented by the following formula (1a).

In the formula (1a), R ^1a and R ^1b have the same meaning as R ¹ , and m1 represents an integer of 0 to 3. R ^1a and R ^1b may be the same as or different from each other. When m1 is an integer of 2 to 3, a plurality of R ^1b existing may be the same or different from each other. m1 may be 0 or 1.

Examples of the thioxanthone compound include 2,4-diethylthioxanthone (DETX), 2-isopropylthioxanthone (2-ITX), 2,4-diisopropylthioxanthone (DITX), 2-ethoxycarbonylthioxanthone, 2-hydroxythioxanthone and the like. Be done.

In the benzophenone compound, examples of R ² and R ³ include a methyl group, a hydroxy group, a diethylamino group, a phenyl group and the like.

N and o may be independently integers of 0 to 4, 0 to 3, 0 to 2 or 0 to 1, respectively, or may be 0.

Examples of the benzophenone compound include benzophenone, 4-methylbenzophenone, 4,4-'bis (diethylamino) benzophenone, 4-phenylbenzophenone and the like.

The photosensitizer is, for example,
It may contain at least one compound selected from the group consisting of 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 1,4-diisopropylthioxanthone, 2-ethoxycarbonylthioxanthone, 2-hydroxythioxanthone and benzophenone.

The content of the photosensitizer is 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0. It may be 6% by mass or more, or 0.8% by mass or more. The content of the photosensitizer may be 5% by mass or less, 3% by mass or less, or 1.5% by mass or less, based on the total mass of the ink composition. The photosensitizer may be used alone or in combination of two or more.

Since the ink composition according to the present embodiment contains the above-mentioned thioxanthone compound and / or the above-mentioned benzophenone compound as a photosensitizer, the luminescent nano is composed of a metal halide having a larger photoabsorbency in the ultraviolet region than the core-shell type quantum dots. Although it contains crystal particles, excellent curability can be obtained even if the amount of the photosensitizer and the photopolymerization initiator added is small. The thioxanthone compound and the benzophenone compound are excellent in solubility in a photopolymerizable compound and also have an excellent photosensitizing effect even if the amount added is small, so that the amount used can be reduced, and the amount of light used can be reduced accordingly. Since it is possible to reduce the amount of the polymerization initiator used, it is possible to suppress an increase in the viscosity of the ink composition. Further, since the thioxanthone compound and the benzophenone compound can easily obtain an ink composition having a small degree of yellowing of the coating film, they can be suitably used for a light conversion layer containing luminescent particles.

Further, among the above-mentioned thioxanthone compounds, 2-isopropylthioxanthone can be particularly preferably used in a photoconversion layer containing luminescent particles because a coating film having an extremely small degree of yellowing can be easily obtained.

The excited triplet state minimum energy ( _ET (S)) of the photosensitizer used in the ink composition of the present invention is abbreviated as the excited triplet state minimum energy ( _ET (PI)) of the photopolymerization initiator. Equal or satisfy the relationship _ET (S)> _ET (PI).

As a photosensitizer used in an ink composition in order to obtain better curability while suppressing the influence of ultraviolet absorption by luminescent nanocrystal particles made of metal halide, it is applied to the ultraviolet wavelength region irradiated for curing. It is preferable to use a compound having a large molecular extinction coefficient. Furthermore, the photosensitizer is more preferably a compound having a higher molecular extinction coefficient than the photopolymerization initiator. Table 1 shows the photopolymerization initiators 2,4,6-trimethylbenzoyl-diphenylphosphinoxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, 2-benzyl. The excitation triplet energy of -2-dimethylamino-4-morpholinobtyrophenone and the photopolymerization initiators benzophenone, 2,4-diethylthioxanthone and 2-isopropylthioxanthone, and the average molecular absorption coefficient for ultraviolet light having a wavelength of 350 to 400 nm. show.

The average molecular extinction coefficient shown in Table 1 is calculated by the following mathematical formula (1).

(In formula (1), Δε represents the average molecular extinction coefficient at a wavelength of 350 to 400 nm, ε (λ) represents the molecular extinction coefficient at wavelength λ, and Δλ represents the wavelength width (50 nm).

From Table 1, for example, when 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one is used as the photopolymerization initiator, 2,4-diethyl is used as the photosensitizer. It is preferable to use thioxanthone or 2-isopropylthioxanthone, and when 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one is used as the photopolymerization initiator, a photosensitizer. As benzophenone, 2,4-diethylthioxanthone or 2-isopropylthioxanthone is preferably used. When 2-benzyl-2-dimethylamino-4-morpholinobtyrophenone is used as the photopolymerization initiator, it is preferable to use 2,4-diethylthioxanthone or 2-isopropylthioxanthone as the photosensitizer.

Further, the photosensitizer used in the present invention is excellent in solubility in a photopolymerizable compound, has an extremely small degree of yellowing, and is easy to obtain an ink composition having extremely excellent curability. Therefore, photopolymerization is possible. It is particularly preferred to use 2,4,6-trimethylbenzoyldiphenylphosphine oxide as the initiator and 2-isopropylthioxanthone as the photosensitizer.

<< Light-scattering particles >>
The ink composition may further contain light scattering particles. The light-scattering particles are preferably, for example, optically inactive inorganic fine particles. When the ink composition contains light-scattering particles, the light-scattering particles can scatter the light from the light source portion irradiated to the light emitting layer (light conversion layer).

Materials that make up the light-scattering particles include, for example, single metals such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum, and gold; silica, barium sulfate, barium carbonate, calcium carbonate. Metal oxides such as talc, titanium oxide, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, alumina white, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, zinc oxide; Metal carbonates such as magnesium, barium carbonate, bismuth hypocarbonate, calcium carbonate; metal hydroxides such as aluminum hydroxide; barium zirconate, calcium zirconate, calcium titanate, barium titanate, strontium titanate, etc. Examples thereof include composite oxides and metal salts such as bismuth subnitrate.

Among them, as a material constituting the light-scattering particles, at least one selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate and silica from the viewpoint of being more excellent in the effect of reducing leakage light. It preferably contains seeds, more preferably contains at least one selected from the group consisting of titanium oxide, barium sulfate and calcium carbonate, and particularly preferably titanium oxide.

When titanium oxide is used, it is preferably surface-treated titanium oxide from the viewpoint of dispersibility. There is a known method as a surface treatment method for titanium oxide, but it is more preferable that the surface treatment contains at least alumina.

Titanium oxide that has been surface-treated to contain alumina means a treatment that precipitates at least alumina on the surface of titanium oxide particles, and silica or the like can be used in addition to alumina. Alumina or silica also contains their hydrates.

In this way, the surface of the titanium oxide particles is uniformly surface-coated by performing a surface treatment containing alumina on the titanium oxide particles, and at least when the titanium oxide particles surface-treated with alumina are used, the titanium oxide particles are dispersed. The sex becomes good.

Further, when the treatment with silica and the treatment with alumina are applied to the titanium oxide particles, the alumina and silica treatment may be performed at the same time, and in particular, the alumina treatment may be performed first, and then the silica treatment may be performed. When the treatments of alumina and silica are performed, the amount of alumina and silica to be treated is preferably more silica than that of alumina.

The surface treatment of titanium oxide with a metal oxide such as alumina or silica can be performed by a wet method. For example, titanium oxide particles surface-treated with alumina or silica can be produced as follows.

Titanium oxide particles (number average primary particle diameter: 200 to 400 nm) are dispersed in water at a concentration of 50 to 350 g / L to form an aqueous slurry, to which a water-soluble silicate or a water-soluble aluminum compound is added. Then, an alkali or an acid is added to neutralize the particles, and silica or alumina is deposited on the surface of the titanium oxide particles. Subsequently, it is filtered, washed and dried to obtain the desired surface-treated titanium oxide. When sodium silicate is used as the water-soluble silicate, it can be neutralized with an acid such as sulfuric acid, nitric acid, or hydrochloric acid. On the other hand, when aluminum sulfate is used as the water-soluble aluminum compound, it can be neutralized with an alkali such as sodium hydroxide or potassium hydroxide.

The content of the light-scattering particles may be 0.5% by mass or more, 1% by mass or more, or 2% by mass or more, based on the total mass of the ink composition, and may be 10% by mass or less, 9% by mass or less, or. It may be 8% by mass or less.

<< Polymer Dispersant >>
The ink composition may further contain a polymer dispersant. The polymer dispersant is a molecule having a weight average molecular weight (Mw) of more than 5,000, and is a compound capable of improving the dispersion stability of light-scattering particles in an ink composition. The polymer dispersant also contributes to the dispersion stability of the luminescent particles.

For the "weight average molecular weight (Mw)", a value measured by gel permeation chromatography (GPC) using polystyrene as a standard material can be adopted.

Examples of the polymer dispersant include acrylic resins, polyester resins, polyurethane resins, polyamide resins, polyether resins, phenol resins, silicone resins, polyurea resins, amino resins, and polyamine resins ( Polyethylene imine, polyallylamine, etc.), epoxy resins, polyimide resins, wood rosins, gum rosins, natural rosins such as tall oil rosins, polymerized rosins, disproportionated rosins, hydrogenated rosins, oxide rosins, maleated rosins, etc. Examples thereof include modified rosin, rosinamine, lime rosin, rosin alkylene oxide adduct, rosin alkyd adduct, rosin derivatives such as rosin-modified phenol, and the like.
Commercially available polymer dispersants include, for example, DISPERBYK (registered trademark) series manufactured by Big Chemie, TEGO (registered trademark) Dispers series manufactured by Ebony, EFKA (registered trademark) series manufactured by BASF, and Japan Lubrizol. SOLSPERSE (registered trademark) series manufactured by Zol, Ajinomoto Fine-Techno's Azispar (registered trademark) series, DISPARLON (registered trademark) series manufactured by Kusumoto Kasei, Floren series manufactured by Kyoeisha Chemical Co., Ltd., and the like can be used.

Further, it is particularly preferable that the polymer dispersant is a block copolymer. The effect of applying the block copolymer to the polymer dispersant is that the block copolymer is composed of a hydrophilic region and a pigment adsorption region, so that high dispersibility can be obtained and a random copolymer weight can be obtained. It is possible to obtain better dispersibility than coalescence or cross-copolymer.

Specifically, in a random copolymer or the like, the monomer monomer constituting the copolymer has a high probability of being sterically or electrically stably arranged in the copolymer at the time of polymer formation. Monomer Since the portion (molecule) in which the monomer is stably arranged is sterically or electrically stable, it often becomes an obstacle when adsorbing on the pigment surface. On the other hand, in the block copolymer type polymer dispersant having a controlled molecular arrangement, the portion that hinders the adsorption of the dispersant to the pigment may be arranged at a position away from the adsorption portion between the pigment and the dispersant. can. That is, by arranging an optimum portion for adsorption in the adsorption portion between the pigment and the dispersant and arranging a portion suitable for the portion in which solvent affinity is required, a pigment having a particularly small crystal size is contained. In the dispersion of the based inkjet ink, it is presumed that good dispersibility can be realized by the molecular arrangement composed of this block copolymer.

The polymer dispersant according to the present invention is not limited as long as it has the above characteristics, and a block copolymer synthesized using a known ethylenically unsaturated monomer can be applied, and the ethylenically unsaturated monomer can be used. , For example, the following can be mentioned.

Stylines and styrene derivatives such as α-methylstyrene or vinyltoluene; vinyl esters of carboxylic acids such as vinyl acetate, vinyl propionate; vinyl halides; ethylenically unsaturated monocarboxylic acids and dicarboxylic acids such as acrylic acids, Monoalkyl esters with methacrylic acid, itaconic acid, maleic acid or fumaric acid, and the above-mentioned alkanols of dicarboxylic acids (preferably those having 1 to 4 carbon atoms), derivatives of the above-mentioned monoalkyl esters, and their derivatives. N-substituted derivatives, aryl esters, and derivatives thereof; amides of unsaturated carboxylic acids such as acrylamide, methacrylamide, N-methylolacrylamide or methacrylamide, N-alkylacrylamide; ethylenic monomers containing sulfonic acid groups and theirs. Ammonium or alkali metal salts such as vinyl sulfonic acid, vinyl benzene sulfonic acid, α-acrylamide methyl propane sulfonic acid, 2-sulfoethylene methacrylate; vinyl amine amides such as vinyl formamide, vinyl acetamide; second, third or second An unsaturated ethylenic monomer containing a quaternary amino group or a nitrogen-containing heterocyclic group, such as vinylpyridine, vinylimidazole, aminoalkyl (meth) acrylate, aminoalkyl (meth) acrylamide, acrylic acid or dimethylaminoethyl methacrylate, acrylic. Acids or di-t-butylaminoethyl methacrylates, or dimethylaminomethylacrylamide or methacrylicamides; zwitterionic monomers such as sulfopropyl (dimethyl) aminopropylacrylate; dienes such as butadiene, isoprene, chloroprene; ( Meta) Acrylic acid esters; vinyl nitriles; vinyl phosphonic acid and derivatives thereof can be mentioned.

Using such an ethylenically unsaturated monomer, a block copolymer can be synthesized according to a known method, for example, a synthesis method such as JP-A-2005-60669 and JP-A-2007-314617.

Among them, it is preferable to use a (meth) acrylic block copolymer, for example, JP-A-60-89452, JP-A-9-62002, P.I. Lutz, P. et al. Massonetal, Polym. Bull. 12, 79 (1984), B.I. C. Anderson, G.M. D. Andrewsetal, Macromolecules, 14, 1601 (1981), K. et al. Hatada, K. et al. Ute, et al, Polym. J. 17,977 (1985), K.K. Hatada, K. et al. Ute, et al, Polym. J. 18, 1037 (1986), Koichi Right Hand, Koichi Hatada, Polymer Processing, 36, 366 (1987), Toshinobu Higashimura, Mitsuo Sawamoto, Journal of Polymer Papers, 46, 189 (1989), M.D. Kuroki, T.I. Aida, J.M. Am. Chem. Sic, 109,4737 (1987), Takuzo Aida, Shohei Inoue, Synthetic Organic Chemistry, 43,300 (1985), D.I. Y. Sogoh, W.M. R. Hertreletal, Macromolecules, 20, 1473 (1987), K. et al. Mathazewskietal, Chem. Rev. It can be synthesized by referring to a known method described in 2001, 101, 2211-2990 and the like.

The polymer dispersant used in the present invention has a basic polar group, and the basic functional groups include primary, secondary and tertiary amino groups, ammonium groups, imino groups, and pyridine, pyrimidine, pyrazine, and the like. Examples thereof include nitrogen-containing heterocyclic groups such as imidazole and triazole. The amine value of the polymer dispersant is preferably 6 to 90 mgKOH / g, more preferably 7 to 70 mgKOH / g, and even more preferably 8 to 50 mgKOH / g. When the amine value of the polymer dispersant is smaller than 6 mgKOH / g, the adsorptivity of the polymer dispersant to the light diffusing particles is low, and when the amine value is larger than 90 mgKOH / g, the polarity is high, and aggregation and storage stability are achieved. It tends to cause deterioration, and the dispersibility of the luminescent particles also deteriorates due to the influence.

The amine value of the polymer dispersant can be measured as follows. Prepare a sample solution prepared by dissolving xg of the polymer dispersant and 1 mL of the bromophenol blue test solution in 50 mL of a mixed solution in which toluene and ethanol are mixed at a volume ratio of 1: 1 and prepare the sample solution with 0.5 mol / L hydrochloric acid. Titration is performed until it turns green, and the amine value can be calculated by the following formula.
Amine value = y / x × 28.05
In the formula, y indicates the titration amount (mL) of 0.5 mol / L hydrochloric acid required for titration, and x indicates the mass (g) of the polymer dispersant.

The content of the polymer dispersant is preferably 0.5 to 50% by mass, more preferably 2 to 30% by mass, and 3 to 20 parts by mass with respect to 100% by mass of the light-scattering particles. Is particularly preferable.

<< Other ingredients >>
The ink composition may further contain components other than those described above. Examples of other components include antioxidants, polymerization inhibitors, leveling agents, chain transfer agents, thermoplastic resins, and the like.

[Antioxidant]
The ink composition may further contain an antioxidant. The antioxidant may be, for example, a phenol compound or a phosphorus-based compound. The content of the antioxidant is preferably 0.01 to 2.0% by mass, preferably 0.02 to 1.0% by mass, based on the total amount of the photopolymerizable compound contained in the ink composition. Is more preferable.

[Polymerization inhibitor]
The ink composition may further contain a polymerization inhibitor. Examples of the polymerization inhibitor include phenol-based compounds, quinone-based compounds, amine-based compounds, thioether-based compounds, N-oxyl compounds, nitroso-based compounds and the like.

The content of the polymerization inhibitor is preferably 0.01 to 1.0% by mass, preferably 0.02 to 0.5% by mass, based on the total amount of the photopolymerizable compounds contained in the ink composition. Is more preferable.

[Leveling agent]
The leveling agent is not particularly limited, but a compound capable of reducing film thickness unevenness when forming a thin film of luminescent particles is preferable.
Examples of such leveling agents include alkyl carboxylates, alkyl phosphates, alkyl sulfonates, fluoroalkyl carboxylates, fluoroalkyl phosphates, fluoroalkyl sulfonates, polyoxyethylene derivatives, and fluoroalkyl ethylene oxide derivatives. , Polyethylene glycol derivatives, alkylammonium salts, fluoroalkylammonium salts and the like.

The content of the leveling agent may be 0.005 to 2% by mass or 0.01 to 0.5% by mass with respect to the total amount of the photopolymerizable compound contained in the ink composition.

[Chain transfer agent]
The chain transfer agent is a component used for the purpose of further improving the adhesion of the ink composition to the substrate.

Examples of the chain transfer agent include aromatic hydrocarbons, halogenated hydrocarbons, mercaptan compounds, sulfide compounds and the like.
The amount of the chain transfer agent added is preferably 0.1 to 10% by mass, more preferably 1.0 to 5% by mass, based on the total amount of the photopolymerizable compound contained in the ink composition. ..

[Thermoplastic resin]
Examples of the thermoplastic resin include urethane resin, acrylic resin, polyamide resin, polyimide resin, styrene maleic acid resin, styrene anhydride maleic acid resin, polyester acrylate resin and the like.

<< Viscosity of ink composition >>
The viscosity of the ink composition at 30 ° C. is preferably in the range of 2 to 20 mPa · s, more preferably in the range of 5 to 15 mPa · s, for example, from the viewpoint of ejection stability during inkjet printing. It is more preferably in the range of 7 to 12 mPa · s. In this case, since the meniscus shape of the ink composition in the ink ejection hole of the ejection head is stable, the ejection control of the ink composition (for example, the control of the ejection amount and the ejection timing) becomes easy. In addition, the ink composition can be smoothly ejected from the ink ejection holes. The viscosity of the ink composition can be measured by, for example, an E-type viscometer.

The viscosity increase rate of the ink composition may be 5% or less, 1% or less, or 0.5% or less, and may be 0.01% or more. The viscosity increase rate of the ink composition is a value calculated by the following formula.
Equation: (η ₁ -η ₀ ) / η ₀ × 100
Here, η ₁ indicates the viscosity of the ink composition after storage at 40 ° C. for 1 week at 30 ° C., and η ₀ indicates the viscosity of the ink composition of the ink composition before storage.

<< Surface tension of ink composition >>
The surface tension of the ink composition is preferably a surface tension suitable for the inkjet printing method. The specific value of the surface tension is preferably in the range of 20 to 40 mN / m, and more preferably in the range of 25 to 35 mN / m. By setting the surface tension in the above range, it is possible to suppress the occurrence of flight bending of droplets of the ink composition. The flight bending means that when the ink composition is ejected from the ink ejection holes, the landing position of the ink composition deviates by 30 μm or more from the target position.

<< Manufacturing method of ink composition >>
The ink composition as described above is prepared by dispersing luminescent particles in a solution containing a photopolymerizable compound, a photopolymerization initiator, a photosensitizer, and, if necessary, other components. can do. Dispersion of luminescent particles can be performed by using, for example, a ball mill, a sand mill, a bead mill, a three-roll mill, a paint conditioner, an attritor, a dispersion stirrer, a disperser such as an ultrasonic wave.

<Ink composition set>
Another embodiment of the present invention is an ink composition set. The ink composition set of one embodiment includes the ink composition of the above-described embodiment. The ink composition set may include an ink composition (non-luminescent ink composition) containing no luminescent particles in addition to the ink composition (luminescent ink composition) of the above-described embodiment. The non-emissive ink composition is, for example, a curable ink composition. The non-emissive ink composition may be a conventionally known ink composition, and has the same composition as the ink composition (light emitting ink composition) of the above-described embodiment except that it does not contain luminescent particles. You may.

Since the non-luminescent ink composition does not contain luminescent particles, when light is incident on the pixel portion formed by the non-luminescent ink composition (the pixel portion containing the cured product of the non-luminescent ink composition). The light emitted from the pixel portion has substantially the same wavelength as the incident light. Therefore, the non-emissive ink composition is preferably used to form a pixel portion having the same color as the light from the light source. For example, when the light from the light source is light having a wavelength in the range of 420 to 480 nm (blue light), the pixel portion formed by the non-emissive ink composition can be a blue pixel portion.

The non-luminescent ink composition preferably contains light-scattering particles. When the non-emission ink composition contains light-scattering particles, the pixel portion formed by the non-emission ink composition can scatter the light incident on the pixel portion, whereby the pixel It is possible to reduce the difference in light intensity of the light emitted from the unit at the viewing angle.

<Light conversion layer, color filter and light emitting element>
Another embodiment of the present invention is a light conversion layer, a color filter and a light emitting device. Hereinafter, the details of the light conversion layer and the color filter obtained by using the ink composition or the ink composition set of the above-described embodiment will be described with reference to the drawings. However, the following embodiment is an embodiment when the ink composition contains light-scattering particles. In the following description, the same reference numerals will be used for the same or equivalent elements, and duplicate description will be omitted.

FIG. 1 is a schematic cross-sectional view of the color filter of one embodiment. As shown in FIG. 1, the color filter 100 includes a base material 40 and a light conversion layer 30 provided on the base material 40. The light conversion layer 30 includes a plurality of pixel units 10 and a light-shielding unit 20.

The optical conversion layer 30 has a first pixel unit 10a, a second pixel unit 10b, and a third pixel unit 10c as the pixel unit 10. The first pixel portion 10a, the second pixel portion 10b, and the third pixel portion 10c are arranged in a grid pattern so as to repeat in this order. The light-shielding portion 20 is located between adjacent pixel portions, that is, between the first pixel portion 10a and the second pixel portion 10b, between the second pixel portion 10b and the third pixel portion 10c, and the third. It is provided between the pixel portion 10c of the above and the first pixel portion 10a. In other words, these adjacent pixel portions are separated from each other by the light-shielding portion 20.

The first pixel portion 10a and the second pixel portion 10b are luminescent pixel portions (light emitting pixel portions) containing a cured product of the ink composition of the above-described embodiment, respectively. The cured product shown in FIG. 1 contains luminescent particles, a curing component, and light scattering particles. The first pixel portion 10a includes a first curing component 13a, a first luminescent particle 11a and a first light scattering particle 12a dispersed in the first curing component 13a, respectively. Similarly, the second pixel portion 10b includes a second curing component 13b and a second luminescent particle 11b and a second light scattering particle 12b dispersed in the second curing component 13b, respectively. .. The curing component is a component obtained by polymerizing a photopolymerizable compound, and includes a polymer of the photopolymerizable compound. In addition to the above polymer, the curing component may contain a component other than the organic solvent contained in the ink composition. In the first pixel portion 10a and the second pixel portion 10b, the first curing component 13a and the second curing component 13b may be the same or different, and may be the same as or different from the first light scattering particles 12a. It may be the same as or different from the second light-scattering particle 12b.

The first luminescent particles 11a are red luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having a emission peak wavelength in the range of 605 to 665 nm. That is, the first pixel portion 10a may be paraphrased as a red pixel portion for converting blue light into red light. The second luminescent particle 11b is a green luminescent nanocrystal particle that absorbs light having a wavelength in the range of 420 to 480 nm and emits light having a emission peak wavelength in the range of 500 to 560 nm. That is, the second pixel portion 10b may be paraphrased as a green pixel portion for converting blue light into green light.

The content of the luminescent particles in the luminescent pixel portion is preferably based on the total mass of the cured product of the luminescent ink composition from the viewpoint of being superior in the effect of improving the external quantum efficiency and obtaining excellent emission intensity. 1% by mass or more, 2% by mass or more, or 3% by mass or more. The content of the luminescent particles is preferably 15% by mass or less based on the total mass of the cured product of the luminescent ink composition from the viewpoint of excellent reliability of the pixel portion and excellent emission intensity. It is 10% by mass or less, or 7% by mass or less.

The content of the light-scattering particles in the luminescent pixel portion is 0.1% by mass or more and 1% by mass based on the total mass of the cured product of the luminescent ink composition from the viewpoint of being more excellent in the effect of improving the external quantum efficiency. It may be more than or equal to 3% by mass or more. The content of the light-scattering particles is 30% by mass or less, 25, based on the total mass of the cured product of the luminescent ink composition, from the viewpoint of improving the effect of improving the external quantum efficiency and the reliability of the pixel portion. It may be mass% or less, 20 parts by mass or less, 15 parts by mass or less, or 10% by mass or less.

The third pixel portion 10c is a non-light emitting pixel portion (non-light emitting pixel portion) containing a cured product of the above-mentioned non-light emitting ink composition. The cured product does not contain luminescent particles, but contains light-scattering particles and a cured component. That is, the third pixel portion 10c includes a third curing component 13c and a third light scattering particle 12c dispersed in the third curing component 13c. The third curing component 13c is, for example, a component obtained by polymerizing a polymerizable compound and contains a polymer of the polymerizable compound. The third light-scattering particle 12c may be the same as or different from the first light-scattering particle 12a and the second light-scattering particle 12b.

The third pixel portion 10c has a transmittance of 30% or more with respect to light having a wavelength in the range of, for example, 420 to 480 nm. Therefore, the third pixel unit 10c functions as a blue pixel unit when a light source that emits light having a wavelength in the range of 420 to 480 nm is used. The transmittance of the third pixel unit 10c can be measured by a microspectroscopy device.

The content of the light-scattering particles in the non-emissive pixel portion is 1% by mass based on the total mass of the cured product of the non-emission ink composition from the viewpoint that the difference in light intensity at the viewing angle can be further reduced. It may be more than 5% by mass, or it may be 10% by mass or more. The content of the light-scattering particles may be 80% by mass or less, and 75% by mass or less, based on the total mass of the cured product of the non-emissive ink composition from the viewpoint of further reducing light reflection. It may be 70% by mass or less.

The thickness of the pixel portion (first pixel portion 10a, second pixel portion 10b, and third pixel portion 10c) may be, for example, 1 μm or more, 2 μm or more, or 3 μm or more. You may. The thickness of the pixel portion (first pixel portion 10a, second pixel portion 10b, and third pixel portion 10c) may be, for example, 30 μm or less, 20 μm or less, or 15 μm or less. You may.

The light-shielding portion 20 is a so-called black matrix provided for the purpose of separating adjacent pixel portions to prevent color mixing and for the purpose of preventing light leakage from a light source. The material constituting the light-shielding portion 20 is not particularly limited, and the curing of the resin composition containing light-shielding particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments in the binder polymer in addition to a metal such as chromium. Objects and the like can be used. The binder polymer used here includes one or a mixture of one or more resins such as polyimide resin, acrylic resin, epoxy resin, polyacrylamide, polyvinyl alcohol, gelatin, casein, and cellulose, photosensitive resin, and O / W. An emulsion-type resin composition (for example, an emulsion of a reactive silicone) or the like can be used. The thickness of the light-shielding portion 20 may be, for example, 0.5 μm or more, and may be 10 μm or less.

The base material 40 is a transparent base material having light transmission, and is, for example, a transparent glass substrate such as quartz glass, Pylex (registered trademark) glass, a synthetic quartz plate, a transparent resin film, an optical resin film, or the like. A flexible base material or the like can be used. Among these, it is preferable to use a glass substrate made of non-alkali glass that does not contain an alkaline component in the glass. Specifically, "7059 glass", "1737 glass", "Eagle 200" and "Eagle XG" manufactured by Corning Inc., "AN100" manufactured by Asahi Glass Co., Ltd., "OA-10G" and "OA-10G" manufactured by Nippon Electric Glass Co., Ltd. OA-11 ”is suitable. These are materials with a small thermal expansion rate and are excellent in dimensional stability and workability in high temperature heat treatment.

The color filter 100 provided with the above optical conversion layer 30 is suitably used when a light source that emits light having a wavelength in the range of 420 to 480 nm is used.

The color filter 100 can be manufactured, for example, by forming the light-shielding portion 20 in a pattern on the base material 40 and then forming the pixel portion 10 in the pixel portion-forming region partitioned by the light-shielding portion 20 on the base material 40. .. The pixel portion 10 has a step of selectively adhering the ink composition (inkjet ink) to the pixel portion forming region on the base material 40 by an inkjet method, and irradiates the ink composition with active energy rays (for example, ultraviolet rays). It can be formed by a method comprising a step of curing an ink composition to obtain a light emitting pixel portion. A luminescent pixel portion can be obtained by using the above-mentioned luminescent ink composition as the ink composition, and a non-luminescent pixel portion can be obtained by using the non-luminescent ink composition.

The method of forming the light-shielding portion 20 is to form a metal thin film such as chromium or a thin film of a resin composition containing light-shielding particles in a region serving as a boundary between a plurality of pixel portions on one surface side of the base material 40. However, a method of patterning this thin film and the like can be mentioned. The metal thin film can be formed by, for example, a sputtering method, a vacuum vapor deposition method, or the like, and the thin film of the resin composition containing the light-shielding particles can be formed, for example, by a method such as coating or printing. Examples of the method for patterning include a photolithography method.

Examples of the inkjet method for forming the pixel portion 10 include a bubble jet (registered trademark) method using an electric heat converter as an energy generating element, a piezojet method using a piezoelectric element, and the like.

The ink composition of the present invention can be cured by irradiation with active energy rays (for example, ultraviolet rays). As the irradiation source (light source), for example, a mercury lamp, a metal halide lamp, a xenon lamp, an LED or the like is used, but the LED is preferable from the viewpoint of reducing the heat load on the coating film and low power consumption.

The wavelength of the irradiated light is preferably 250 nm to 440 nm, more preferably 300 nm to 400 nm. When an LED is used, it is preferably 350 nm or more and 400 nm or less, for example, from the viewpoint of sufficiently curing a film thickness of 10 μm or more. The light intensity is preferably 0.2 to 2 kW / cm ² , more preferably 0.4 to 1 kW / cm ² . A light intensity of less than 0.2 kW / cm ² cannot sufficiently cure the coating film, and a light intensity of 2 kW / cm ² or more causes unevenness in the curing degree between the surface and the inside of the coating film, resulting in smoothness of the coating film surface. It is not preferable because it is inferior in sex. The irradiation amount (exposure amount) of light is preferably 10 mJ / cm ² or more, and more preferably 4000 mJ / cm ² or less.
The coating film can be cured in the air or in an inert gas, but more preferably in an inert gas in order to suppress oxygen inhibition on the surface of the coating film and oxidation of the coating film. Examples of the inert gas include nitrogen, argon, carbon dioxide and the like. By curing the coating film under such conditions, the coating film can be completely cured, so that the external quantum efficiency of the obtained light conversion layer 9 can be further improved.

For example, the light conversion layer is a pixel portion containing a cured product of a luminescent ink composition containing blue-emitting nanocrystal particles in place of the third pixel portion 10c or in addition to the third pixel portion 10c ( It may be provided with a blue pixel portion). Further, even if the light conversion layer includes a pixel portion (for example, a yellow pixel portion) containing a cured product of a luminescent ink composition containing nanocrystal particles that emit light of colors other than red, green, and blue. good. In these cases, it is preferable that each of the luminescent particles contained in each pixel portion of the optical conversion layer has an absorption maximum wavelength in the same wavelength range.

Further, at least a part of the pixel portion of the light conversion layer may contain a cured product of a composition containing a pigment other than luminescent particles.

Further, the color filter may be provided with an ink-repellent layer made of a material having an ink-repellent property narrower than that of the light-shielding portion on the pattern of the light-shielding portion. Further, instead of providing an ink-repellent layer, a photocatalyst-containing layer as a wettable variable layer is formed in a solid coating shape in a region including a pixel portion forming region, and then light is applied to the photocatalyst-containing layer via a photomask. Irradiation may be performed for exposure to selectively increase the parental ink property of the pixel portion forming region. Examples of the photocatalyst include titanium oxide and zinc oxide.

Further, the color filter may be provided with an ink receiving layer containing hydroxypropyl cellulose, polyvinyl alcohol, gelatin, etc. between the base material and the pixel portion.

Further, the color filter may be provided with a protective layer on the pixel portion. This protective layer flattens the color filter and prevents the components contained in the pixel portion, or the components contained in the pixel portion and the components contained in the photocatalyst-containing layer from elution into the liquid crystal layer. It is provided. As the material constituting the protective layer, a material used as a known protective layer for a color filter can be used.

Further, in addition to the above-mentioned luminescent particles, the pixel portion of the light conversion layer of the present embodiment may further contain a pigment having substantially the same color as the luminescent color of the luminescent particles. In order to contain the pigment in the pixel portion, the pigment may be contained in the ink composition.

Further, among the red pixel portion (R), the green pixel portion (G), and the blue pixel portion (B) in the optical conversion layer of the present embodiment, one or two types of luminescent pixel portions are luminescent particles. It may be a pixel portion containing a coloring material without containing the above. As the color material that can be used here, a known color material can be used. For example, as the color material used for the red pixel portion (R), a diketopyrrolopyrrole pigment and / or an anionic red organic dye is used. Can be mentioned. Examples of the coloring material used for the green pixel portion (G) include at least one selected from the group consisting of a halogenated copper phthalocyanine pigment, a phthalocyanine-based green dye, and a mixture of a phthalocyanine-based blue dye and an azo-based yellow organic dye. Examples of the coloring material used for the blue pixel portion (B) include an ε-type copper phthalocyanine pigment and / or a cationic blue organic dye. The amount of these coloring materials used is 1 to 5 mass based on the total mass of the pixel portion (cured product of the ink composition) from the viewpoint of preventing a decrease in transmittance when contained in the optical conversion layer. % Is preferable.

The color filter can be used for a color filter such as an organic EL element (OLED) which is a light emitting element and a liquid crystal display element. In the present invention, it is particularly useful as an organic EL element (OLED), and the configuration of the organic EL element will be briefly described below.

The light emitting element, which is an organic EL element, has an organic EL light source unit partitioned for each pixel on the substrate, and the blue light emitted from the organic EL light source unit is red (R) above the organic EL light source unit. ), A light emitting element provided with a color filter that converts to green (G). The organic EL light source unit partitioned for each pixel may have a packed layer and a protective layer together with the organic EL light emitting member.

Such a light emitting element absorbs and re-emits or transmits the light emitted from the organic EL light source unit (EL layer) by the color filter, and extracts it as red light, green light, or blue light from the upper substrate side to the outside. Can be done.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples.

The following compounds were prepared as the photosensitizer (A).
(A-1) 2-Isopropylthioxanthone (ITX): _ET (S) = 62 kcal / mol
(A-2) _Benzophenone : ET (S) = 69 kcal / mol
(A-3): 1,2-Benz anthracene: _ET (S) = 47 kcal / mol

The following compounds were prepared as the photopolymerization initiator (B).
(B-1) 2,4,6-trimethylbenzoyl-diphenylphosphine oxide: ET (PI) = 62 kcal / mol, product name: _Omnirad® TPO-H, IGM Resins B.I. V. (B-2) 2-Methyl-1- [4- (Methylthio) Phenyl] -2-morpholinopropane-1-one: ET (PI) = 61 kcal / mol, Product name: _Omnirad 907, IGM Resins B .. V. (B-3) 2-Benzyl-2-dimethylamino-4-morpholinobtyrophenone: ET (PI) = 60 kcal / mol, product name: _Omnirad 369, IGM Resins B. V. Made by the company

The following compounds were prepared as the antioxidant (C).
(C-1) Irganox (registered trademark) 1010 (phenolic): manufactured by BASF Japan Co., Ltd. (C-2) HOSTANOX (registered trademark) P-EPQ (hypophosphorous acid diester): manufactured by Clariant Chemicals Co., Ltd.

The following compounds were prepared as the photopolymerizable compound (D).
(D-1) Isobornyl methacrylate: trade name Light Ester IB-X, manufactured by Kyoeisha Chemical Co., Ltd.,
(D-2) Dodecyl methacrylate: Brand name Light Ester L, manufactured by Kyoeisha Chemical Co., Ltd.,
(D-3) Phenoxyethyl methacrylate: trade name Light Ester PO, manufactured by Kyoeisha Chemical Co., Ltd. (D-4) 1.6-hexanediol dimethacrylate: trade name Light Ester 1.6HX, manufactured by Kyoeisha Chemical Co., Ltd. (D-) 5) Dimethylol-tricyclodecanediacrylate: trade name Light acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd. (D-6) Glycerin propoxytriacrylate: trade name OTA-480, manufactured by Dycel Ornex Co., Ltd.

The following titanium oxide was prepared as the light scattering particles (E).
(E-1) Titanium oxide (trade name: CR-60-2, manufactured by Ishihara Sangyo Co., Ltd.)

The following compounds were prepared as the polymer dispersant (F).
(F-1) Efka PX-4701 (manufactured by BASF Japan Ltd.)

<Preparation of luminescent particle (X) dispersion liquid>
(Preparation of luminescent particle dispersion liquid 1)
First, 0.81 g of cesium carbonate, 40 mL of 1-octadecene and 2.5 mL of oleic acid were mixed to obtain a mixed solution. Next, this mixed solution was dried under reduced pressure at 120 ° C. for 10 minutes, and then heated at 150 ° C. under an argon atmosphere. This gave a cesium-oleic acid solution.
On the other hand, 138.0 mg of lead (II) bromide and 10 mL of 1-octadecene were mixed to obtain a mixed solution. Next, the mixed solution was dried under reduced pressure at 120 ° C. for 10 minutes, and then 1 mL of 3-aminopropyltriethoxysilane was added to the mixed solution under an argon atmosphere. Then, 1.3 mL of a cesium-oleic acid solution was added to the above mixture at 140 ° C., and the mixture was reacted by heating and stirring for 5 seconds, and then cooled in an ice bath.

Then, the reaction solution was stirred under the atmosphere (23 ° C., humidity 45%) for 60 minutes, and then 20 mL of ethanol was added.
The obtained suspension was centrifuged (3,000 rpm, 5 minutes) to recover the solid matter, and luminescent particles X-1 were obtained.
The luminescent particles X-1 were perovskite-type lead cesium tribromide crystals having a surface layer, and the average particle size was 10 nm as observed by a transmission electron microscope. The surface layer was a layer composed of 3-aminopropyltriethoxysilane, and its thickness was 1 nm. That is, the luminescent particles X-1 were silica-coated particles.
Further, the luminescent particles X-1 were dispersed in isobornyl methacrylate so that the solid content concentration was 2.5% by mass to obtain a luminescent particle dispersion liquid 1 in which the luminescent particles X-1 were dispersed. ..

(Preparation of luminescent particle dispersion liquid 2)
A luminescent particle dispersion 2 was obtained in the same manner as the luminescent particle dispersion 1 except that lauryl methacrylate was used instead of isobornyl methacrylate.

(Preparation of luminescent particle dispersion liquid 3)
190 parts by mass of heptane was supplied to a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas introduction tube, and the temperature was raised to 85 ° C. After reaching the same temperature, 20 parts by mass of lauryl methacrylate, 3.5 parts by mass of dimethylaminoethyl methacrylate and 0.5 parts by mass of dimethyl-2,2-azobis (2-methylpropionate). The mixture dissolved in heptane by mass was added dropwise to the heptane of the four-necked flask over 3.5 hours, and even after the completion of the addition, the mixture was kept at the same temperature for 10 hours to continue the reaction. Then, after lowering the temperature of the reaction solution to 50 ° C., a solution prepared by dissolving 0.01 part by mass of t-butylpyrocatechol in 1.0 part by mass of heptane was added, and 1.0 part by mass of glycidyl methacrylate was further added. Was added, the temperature was raised to 85 ° C., and the reaction was continued at the same temperature for 5 hours. As a result, a solution containing the polymer (P) was obtained. The amount of the non-volatile component (NV) contained in the solution was 25.1% by mass, and the weight average molecular weight (Mw) of the polymer (P) was 10,000.

Then, in a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas introduction tube, 26 parts by mass of heptane, 3 parts by mass of the above-mentioned luminescent particles X-1 and 3.6 parts by mass were added. A solution containing the above-mentioned polymer (P) was supplied. Further, in the above four-necked flask, 0.2 parts by mass of ethylene glycol dimethacrylate, 0.4 parts by mass of methyl methacrylate, and 0.12 parts by mass of dimethyl-2,2-azobis (2-methylpropionate). ) And supplied. Then, the mixed solution in the four-necked flask was stirred at room temperature for 30 minutes, then heated to 80 ° C., and the reaction was continued at the same temperature for 15 hours. After completion of the reaction, the polymer that was not adsorbed on the luminescent particles X-1 in the reaction solution was separated by centrifugation, and then the precipitated particles were vacuum dried at room temperature for 2 hours to obtain luminescent particles as mother particles. Polymer-coated luminescent particles X-2 were obtained in which the surface of X-1 was coated with a polymer layer made of a hydrophobic polymer.

When the obtained polymer-coated luminescent particles X-2 were observed with a transmission electron microscope, a polymer layer having a thickness of about 10 nm was formed on the surface of the luminescent particles X-2. Then, the obtained polymer-coated luminescent particles X-2 were dispersed in isobornyl methacrylate so that the solid content concentration was 2.5% by mass to obtain a luminescent particle dispersion liquid 3.

(Preparation of luminescent particle dispersion liquid 4)
First, the same hollow silica particles (“SiliNax SP-PN (b)” manufactured by Nittetsu Mining Co., Ltd.) as those used in the luminescent particle dispersion 1 were dried under reduced pressure at 150 ° C. for 8 hours. Next, 200.0 parts by mass of dried hollow silica particles were weighed into a Kiriyama funnel.

Next, under an argon atmosphere, 63.9 parts by mass of cesium bromide, 110.1 parts by mass of lead (II) bromide and 3000 parts by mass of N-methylformamide were supplied to a three-necked flask at 50 ° C. Stirring for 30 minutes gave a lead cesium tribromide solution.

Next, the hollow silica particles are supplied to the three-necked flask, the obtained lead tribromide solution is impregnated into the hollow silica particles, and then the excess lead tribromide cesium solution is removed by filtration to form a solid. I recovered the thing. Then, the obtained solid material was dried under reduced pressure at 120 ° C. for 1 hour to obtain luminescent particles X-3 in which nanocrystals composed of perovskite-type lead cesium tribromide were encapsulated in hollow silica particles. The luminescent particles X-3 are hollow particle-encapsulating luminescent particles.

By dispersing the obtained luminescent particles X-3 in isobornyl methacrylate so that the solid content concentration is 2.5% by mass, a luminescent particle dispersion liquid 4 in which the luminescent particles X-3 are dispersed is obtained. rice field.

(Preparation of luminescent particle dispersion liquid 5)
First, the luminescent particles X-3 as the mother particles are hydrophobic in the same manner as the polymer-coated luminescent particles X-2, except that the luminescent particles X-3 are used instead of the luminescent particles X-1. Polymer-coated luminescent particles X-4 coated with a polymer layer made of a polymer were obtained. Then, the luminescent particle dispersion 5 was obtained in the same manner as the luminescent particle dispersion 2 except that the polymer-coated luminescent particles X-4 were used instead of the polymer-coated luminescent particles X-2 as the luminescent particles. rice field.

(Preparation of luminescent particle dispersion liquid 6)
Luminescent particles in the same manner as the luminescent particle dispersion 1 except that the solid content concentration of the luminescent particles X-1 was replaced with 2.5% by mass so that the solid content concentration was 5% by mass. A luminescent particle dispersion 6 in which X-1 was dispersed was obtained.

(Preparation of luminescent particle dispersion liquid 7)
First, 0.814 parts by mass of cesium carbonate, 40 parts by mass of octadecene, and 2.5 parts by mass of oleic acid are supplied to a four-necked flask equipped with a thermometer, a stirrer, a septum and a nitrogen gas introduction tube. Then, under a nitrogen atmosphere, the mixture was heated and stirred at 150 ° C. until a uniform solution was obtained. After all were dissolved, it was cooled to 100 ° C. to obtain a cesium oleate solution.

Next, 0.069 parts by mass of lead bromide (II) and 5 parts by mass of octadecene were supplied to a four-necked flask equipped with a thermometer, a stirrer, septum and a nitrogen gas introduction tube under a nitrogen atmosphere. , 120 ° C. for 1 hour with stirring. Subsequently, 0.5 parts by mass of oleylamine and 0.5 parts by mass of oleic acid were supplied to the four-necked flask, and the mixture was heated and stirred at 160 ° C. under a nitrogen atmosphere until a uniform solution was obtained. Further, 0.4 parts by weight of a cesium oleate solution was supplied to the four-necked flask, and the mixture was stirred at 160 ° C. for 5 seconds, and then the four-necked flask was ice-cooled. By centrifuging the obtained reaction solution and removing the supernatant, 0.45 parts by mass of perovskite-type lead tribromide cesium crystals coordinated with oleic acid and oleylamine as luminescent particles X-5. Got Then, the obtained luminescent particles X-5 were dispersed in isobornyl methacrylate so that the solid content concentration was 2.5% by mass to obtain a luminescent particle dispersion liquid 7.

<Preparation of light-scattering particle dispersion>
In a container filled with nitrogen gas, 10.0 parts by mass of titanium oxide (“CR60-2” manufactured by Ishihara Sangyo Co., Ltd.) and polymer dispersant “Efka PX4701” (amine value: 40.0 mgKOH / g, BASF Japan) 1.0 part by mass of phenoxyethyl methacrylate (light ester PO; manufactured by Kyoeisha Chemical Co., Ltd.) 14.0 parts by mass was mixed. Further, zirconia beads (diameter: 1.25 mm) were added to the obtained formulation, the container was sealed tightly, and the mixture was shaken for 2 hours using a paint conditioner to disperse the compound to disperse light-diffusing particles. I got body 1. The average particle size of the light diffusing particles after the dispersion treatment was 0.245 μm as measured by using NANOTRAC WAVE II.

<Preparation of ink composition>
(Preparation of Ink Composition (1))
As the ink composition of Example 1, 6.0 parts by mass of a light-emitting particle dispersion liquid 1 (light-emitting particle concentration 2.5% by mass) and a light-scattering particle dispersion 1 (titanium oxide content 40.0% by mass) ) 0.75 parts by mass and "lauryl methacrylate" as a photopolymerizable compound (product name: Light Ester LM, manufactured by Kyoeisha Chemical Co., Ltd.) 0.75 parts by mass and "1,6-hexanediol dimethacrylate" (product name) : Light ester 1,6-HX, manufactured by Kyoeisha Chemical Co., Ltd.) 2.0 parts by mass and "diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide" as a photopolymerization initiator (product name: Omnirad TPO-H) , BASF Japan Co., Ltd.) 0.3 parts by mass, "2-isopropylthioxanthone" as a photosensitizer (product name: SPEEDCURE (registered trademark) 2-ITX, manufactured by LAMBSON) 0.1 parts by mass, antioxidant As an agent, "pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]" (product name: Irganox1010, manufactured by BASF Japan Co., Ltd.) 0.05 parts by mass and "Tetrakiss ( 2,4-Di-tert-butylphenyl) -1,1-biphenyl-4,4'-diylbisphosphonite "(Product name: HOSTANOX P-EPQ, manufactured by Clarianto Chemicals Co., Ltd.) 0.05 parts by mass After mixing and uniformly dissolving in a container filled with argon gas, the solution was filtered through a filter having a pore size of 5 μm in a glove box. Further, argon gas was introduced into the container containing the obtained filter, and the inside of the container was saturated with argon gas. Then, the pressure was reduced to remove the argon gas, whereby the ink composition (1) was obtained. The content of luminescent particles is 1.5% by mass, the content of IB-X is 58.5% by mass, the content of LM is 6.5% by mass, and the content of PO is 4. It is 2% by mass, the content of 1,6-HX is 20.0% by mass, the content of TPO-H is 3.0% by mass, and the content of 2-ITX is 1.0% by mass. The content of Irganox 1010 is 0.5% by mass, the content of P-EPQ is 0.5% by mass, the content of light-scattering particles is 3.0% by mass, and the polymer is dispersed. The content of the agent was 0.3% by mass. The content is based on the total mass of the ink composition.

(Preparation of ink compositions (2) to (13) and (C1) to (C3))
Luminous particle dispersions 1 to 7, light scattering particle dispersions, photopolymerizable compounds D-2 to D-6, photopolymerization initiators B-1 to B-3, photosensitizers A-1 to A- 3. Examples 2 to 2 under the same conditions as the preparation of the ink composition (1), except that the addition amounts of the antioxidants C-1 and C-2 were changed to the addition amounts shown in Tables 1 and 2 below. 13 ink compositions (2) to (13) and ink compositions (C1) to (C3) of Comparative Examples 1 to 3 were obtained.

<Preparation of optical conversion layer>
(Preparation of optical conversion layer 1)
The ink composition (1) was applied onto a glass substrate (“EagleXG®” manufactured by Corning Inc.) with a spin coater so that the film thickness after drying was 15 μm.
The obtained film was irradiated with ultraviolet light having an LED lamp wavelength of 395 nm under a nitrogen atmosphere at an exposure amount of 10 J / cm ² . As a result, the ink composition was cured to form a layer made of the cured product of the ink composition on the glass substrate, which was used as a light conversion layer.

<Evaluation of ink composition and optical conversion layer>
(Example 1)
(Stability of ink viscosity)
The viscosity stability of the ink composition (1) was evaluated by the following method. The viscosity of the ink composition immediately after preparation was compared with the viscosity of the ink composition stored in a constant temperature bath at 40 ° C. for 1 week after preparation, and the rate of increase in viscosity was calculated. Specifically, the viscosity of the ink composition immediately after preparation was set to η ₀ , and the viscosity of the ink composition stored in a constant temperature bath at 40 ° C. for 1 week after preparation was set to η ₁ , and the calculation was performed using the following formula. %Met.
Viscosity increase rate (%) = (η ₁ -η ₀ ) / η ₀ × 100

(Dispersion stability)
After the ink composition (1) was left in the air and at room temperature for 10 days, the presence or absence of a precipitate on the bottom surface of the container was visually confirmed. The dispersion stability was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
A: No precipitate is formed.
B: Very little precipitate is formed. The precipitate dissolves by shaking.
C: A little more precipitate is generated. Precipitation remains even after shaking.

The results are shown in Tables 2 to 4.

(Currability of coating film)
When the surface of the obtained light conversion layer 1 was evaluated by palpation using a cotton swab according to the following criteria, the surface of the coating film was not scratched and there was no tack feeling.
〔Evaluation criteria〕
⊚: The surface of the coating film is not scratched and there is no feeling of tackiness.
◯: The surface of the coating film is not scratched and there is a slight tack feeling, but there is no problem in practical use.
Δ: The surface of the coating film is slightly scratched and has a tacky feeling.
X: The surface of the coating film is scratched, and a part of the cured film adheres to the cotton swab.

(Evaluation of surface smoothness)
The surface roughness (Sa value; unit μm) of the obtained optical conversion layer 1 was measured using VertScan3.0R4300 of the rhombus system and found to be 0.07 μm.

(Evaluation of external quantum efficiency (EQE))
An integrating sphere is installed above the blue LED (peak emission wavelength: 450 nm) manufactured by CCS Co., Ltd. as a surface emission light source, and a radiation spectrophotometer manufactured by Otsuka Electronics Co., Ltd. (trade name "MCPD-9800") is placed on this integrating sphere. ") Was connected. Next, the above-mentioned evaluation sample was inserted between the blue LED and the integrating sphere, the blue LED was turned on, and the observed spectrum and the illuminance at each wavelength were measured by a radiation spectrophotometer. From the obtained spectrum and illuminance, the external quantum efficiency (EQE) was obtained as follows.

The external quantum efficiency is a value indicating how much of the light (photons) incident on the optical conversion layer is emitted to the observer side as fluorescence. Therefore, if this value is large, it indicates that the light conversion layer is excellent in light emission characteristics, which is an important evaluation index. The external quantum efficiency (EQE) is calculated by the following equation (a).
EQE [%] = P2 / E (Blue) x 100 ... (a)
In the formula, E (Blue) represents the total value of "illuminance x wavelength ÷ hc" in the wavelength range of 380 to 490 nm, and P2 represents the total value of "illuminance x wavelength ÷ hc" in the wavelength range of 500 to 650 nm. These are the values corresponding to the observed number of photons. In addition, h represents Planck's constant and c represents the speed of light.
Here, the EQE means that the larger the value, the smaller the deterioration of the semiconductor nanocrystal particles due to the ultraviolet rays in the curing step of the coating film, that is, the more excellent the stability to the ultraviolet rays. For use as an optical conversion layer, the EQE is preferably 20% or more, more preferably 25% or more, which means that it is excellent.
The EQE measured immediately after the optical conversion layer 1 was manufactured was set to the initial external quantum efficiency EQE ₀ , and the EQE ₀ was measured and found to be 32%.

(Evaluation of external quantum efficiency retention rate)
Then, the light conversion layer 1 was stored at room temperature and in the air for 10 days. The external quantum efficiency after storage was set to EQE _h , and the external quantum retention rate [%] of the optical conversion layer was calculated by the following equation (b) and found to be 89%.
External quantum retention rate [%] = EQE _h / EQE ₀ × 100… (b)
It is desirable that the optical conversion layer has a higher EQE _h in addition to EQE ₀ , and the higher the external quantum efficiency retention rate, the higher the stability of the optical conversion layer containing luminescent particles to oxygen gas and water vapor. do.

(Examples 2 to 13)
Similar to Example 1, the viscosity stability of the ink compositions (2) to (13), except that the ink compositions (2) to (13) of the present invention were used instead of the ink composition (1). The dispersion stability was evaluated. Further, the light conversion layers 2 to 13 were prepared in the same manner as in Example 1 except that the ink compositions (2) to (13) of the present invention were used instead of the ink composition (1), and the curability was improved. The surface roughness Sa (μm), the external quantum efficiency EQE ₀ (%), and the external quantum efficiency retention rate (%) were evaluated.

(Comparative Examples 1 to 3)
Viscosity stability of the comparative ink compositions (C1) to (C3) as in Example 1 except that the comparative ink compositions (C1) to (C3) were used instead of the ink composition (1). , The dispersion stability was evaluated. Further, the optical conversion layers C1 to C3 were prepared in the same manner as in Example 1 except that the comparative ink compositions (C1) to (C3) were used instead of the ink composition (1), and the curability and surface were improved. Roughness Sa (μm), external quantum efficiency EQE ₀ (%), and external quantum efficiency retention rate (%) were evaluated.

The results are shown in Tables 2 to 4.

10 ... pixel unit, 10a ... first pixel unit, 10b ... second pixel unit, 10c ... third pixel unit, 11a ... first light emitting particle, 11b ... second light emitting particle, 12a ... second 1 light-scattering particle, 12b ... second light-scattering particle, 12c ... third light-scattering particle, 20 ... light-shielding portion, 30 ... light conversion layer, 40 ... base material, 100 ... color filter.

Claims

It contains luminescent particles containing semiconductor nanocrystal particles made of metal halide, a photopolymerizable compound, a photosensitizer, and a photopolymerization initiator.
The photosensitizer is based on the following general formula (1):

[In the formula (1), R 1 represents an alkyl group, a hydroxy group, or an alkoxycarbonyl group having 2 to 3 carbon atoms, m represents an integer of 1 to 4, and m is an integer of 2 to 4. In this case, the plurality of R 1s may be the same or different from each other. ]
The thioxanthone compound represented by, or the following general formula (2):

[In formula (2), R 2 and R 3 independently represent an alkyl group, a hydroxy group, a dialkylamino group, or a phenyl group, and n and o each independently represent an integer of 0 to 5, where n is. When it is an integer of 2 to 5, the plurality of R 2s may be the same or different from each other, and when o is an integer of 2 to 5, the plurality of R 3s are the same as each other. May be different. ]
An ink composition for inkjet, which is a benzophenone compound represented by.
The photosensitizer is at least one compound selected from the group consisting of 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 1,4-diisopropylthioxanthone, 2-ethoxycarbonylthioxanthone, 2-hydroxythioxanthone and benzophenone. The ink composition for inkjet according to claim 1.
The photopolymerization initiators are 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one and 2-benzyl-2-one. The ink composition for inkjet according to claim 1 or 2, which comprises at least one compound selected from the group consisting of dimethylamino-4-morpholinobtyrophenone.
The inkjet ink composition according to any one of claims 1 to 3, wherein the content of the photopolymerization initiator is 2 to 10% by mass based on the total mass of the inkjet ink composition.
The inkjet ink composition according to any one of claims 1 to 4, further containing light-scattering particles.
The inkjet ink composition according to any one of claims 1 to 5, further containing a polymer dispersant.
A cured product of the inkjet ink composition according to any one of claims 1 to 6.
A plurality of pixel portions and a light-shielding portion provided between the plurality of pixel portions are provided.
The plurality of pixel portions are light conversion layers having a light emitting pixel portion containing a cured product of the ink composition according to any one of claims 1 to 6.
A color filter including the optical conversion layer according to claim 8.
A light emitting device including the color filter according to claim 9.