KR102557679B1 - Ink composition for inkjet, light conversion layer and color filter - Google Patents

Abstract

The problem to be solved by the present invention is to provide an ink composition for inkjet containing semiconductor nanocrystals containing metal halide capable of forming a cured film having excellent light resistance under high temperature, a light conversion layer using the ink composition, and a color filter. According to the ink composition for inkjet containing luminescent particles containing metal halide-containing semiconductor nanocrystal particles, a photopolymerizable compound, a photopolymerization initiator, and a NOR-type hindered amine compound having a structure represented by the following formula (1), the above problems can be solved.

[In Formula (1), R ¹ to R ⁵ each independently represent a hydrocarbon group, and * represents a bond.]

Description

Ink composition for inkjet, light conversion layer and color filter

The present invention relates to an ink composition for inkjet, a light conversion layer, and a color filter.

In recent years, a high color gamut of displays has been strongly demanded. Therefore, instead of red organic pigment particles or green organic pigment particles, quantum dots, quantum rods, other inorganic phosphor particles, etc., using luminescent nanocrystal particles, such as red pixels, green pixels, etc. Research into color filters having pixel portions is being actively pursued. The color filter is desired to have a fine pattern, and since unnecessary consumption of luminescent nanocrystal particles occurs in the photolithography method, an inkjet method (inkjet method) using an ultraviolet curable ink composition is used to form a light conversion layer. For example, Patent Literature 1 discloses an ink-jet ink composition containing luminescent nanocrystal particles containing core/shell type semiconductor nanocrystals, and a wavelength conversion member containing a cured film of the composition.

Luminescent nanocrystal particles such as semiconductor nanocrystals are easily deteriorated by light irradiation in the presence of water vapor, oxygen, or the like. In particular, since the light conversion layer is heated by strong light from the backlight, there is a problem that the luminescent nanocrystal particles are deteriorated by light irradiation at a high temperature and the luminous intensity is lowered. Regarding this problem, for example, by adding a hindered amine-based compound to a curable composition containing core/shell type semiconductor nanocrystals, a technique for improving the light resistance in a high-temperature environment of a cured film obtained has been proposed (see Patent Document 2).

On the other hand, when core/shell type semiconductor nanocrystals are used as a light conversion material, strict particle size control of the core part and the shell part is required to adjust the light emission wavelength region, and the difficulty of producing ink with stable quality industrially is high. Therefore, as inorganic luminescent particles whose particle size can be adjusted relatively easily, in recent years, semiconductor crystals containing metal halide, in particular, compounds represented by CsPbX ₃ (X represents Cl, Br or I) Semiconductor nanocrystals having a perovskite-type crystal structure have been discovered and are attracting attention (for example, Patent Document 3). Semiconductor nanocrystals having a perovskite-type crystal structure are not only relatively easy to control the particle size, but also have the advantage that the emission wavelength can be arbitrarily changed according to the type of halogen element, and the half width of the peak width of the emission spectrum is small.

Japanese Unexamined Patent Publication No. 2020-076976 International Publication No. 2019/186734 Japanese Patent Publication No. 2018-506625

However, there is a problem that light resistance under high temperature of the obtained cured film (light conversion layer) is insufficient only by applying the perovskite type semiconductor nanocrystal to an inkjet ink composition and adding the hindered amine compound disclosed in Patent Document 2.

The problem to be solved by the present invention is to provide an ink composition for inkjet containing semiconductor nanocrystals containing metal halide capable of forming a cured film having excellent light resistance under high temperature, a light conversion layer using the ink composition, and a color filter.

As a result of intensive studies, the inventors of the present invention have found that a cured film having excellent light resistance at high temperatures can be formed in an inkjet ink composition containing semiconductor nanocrystals containing a metal halide, when it has a specific structure of a hindered amine compound, and reached the present invention.

That is, the ink composition for inkjet of the present invention is characterized by containing luminescent particles containing semiconductor nanocrystal particles containing metal halide, a photopolymerizable compound, a photopolymerization initiator, and a NOR-type hindered amine compound having a structure represented by the following formula (1).

[In Formula (1), R ¹ to R ⁵ each independently represent a hydrocarbon group, and * represents a bond.]

It is preferable that the NOR-type hindered amine compound has a melting point of 70°C or higher. It is preferable that the molecular weight of the NOR type hindered amine compound is 1000 or more.

The luminescent particle is a particle having a surface layer formed on the surface of the semiconductor nanocrystal particle, and the surface layer preferably contains a polymer of a silane compound having an associative group capable of bonding to the surface of the semiconductor nanocrystal particle and a hydrolysable silyl group.

The luminescent particles may further include hollow particles having an inner space capable of accommodating the semiconductor nanocrystal particles and pores communicating with the inner space, and the semiconductor nanocrystal particles may be accommodated in the inner space.

It is preferable that the SP value of the photopolymerizable compound is 10.0 or less. It is preferable that the photopolymerizable compound has a cyclic structure.

The ink composition preferably further contains light scattering particles. It is preferable that the ink composition further contains a polymer dispersant.

It is preferable that the viscosity in 30 degreeC of an ink composition is 7-12 mPa*s.

Another aspect of the present invention is a light conversion layer having a light-emitting pixel portion including a plurality of pixel portions and a light-shielding portion provided between the plurality of pixel portions, wherein the plurality of pixel portions include a cured product of the ink composition for inkjet. Another aspect of the present invention relates to a color filter including the light conversion layer.

According to one aspect of the present invention, it is possible to provide an ink composition for inkjet capable of forming a cured film having excellent light resistance at high temperatures. According to another aspect of the present invention, a light conversion layer and a color filter using the ink composition for inkjet may be provided.

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

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described. This invention is not limited to the following embodiment.

<Ink composition>

One embodiment of the present invention is an ink composition for inkjet (hereinafter, simply referred to as "ink composition"). An ink composition according to one embodiment contains luminescent particles containing metal halide-containing semiconductor nanocrystal particles (hereinafter simply referred to as “nanocrystal particles”), a photopolymerizable compound, a photopolymerization initiator, and a NOR-type hindered amine compound represented by formula (1) described later.

The ink composition may be, for example, an ink composition for forming a light conversion layer (eg, for forming a color filter pixel portion) used to form a light conversion layer (pixel portion of a light conversion layer) included in a color filter or the like. The ink composition is a composition (inkjet ink) used in an ultraviolet curable inkjet method.

<<luminescent particles>>

Luminescent particles include nanocrystal particles. The nanocrystal particle is a nano-sized crystal (nanocrystal particle) that contains a metal halide and absorbs excitation light to emit fluorescence or phosphorescence. As light-emitting nanocrystals containing metal halide, for example, quantum dots having a perovskite-type crystal structure described later are widely known. The nanocrystal particles are crystals having a maximum particle diameter of 100 nm or less as measured by a transmission electron microscope or a scanning electron microscope, for example.

The nanocrystal particles may emit fluorescence or phosphorescence by being excited by, for example, light energy or electrical energy of a predetermined wavelength.

The metal halide-containing nanocrystal particle is a compound represented by the general formula: A _a M _b X _c .

In formula, A is at least 1 sort(s) of an organic cation and a metal cation. Examples of organic cations include ammonium, formamidinium, guanidinium, imidazolium, pyridinium, pyrrolidinium, and protonated thiourea. Examples of metal cations include cations such as Cs, Rb, K, Na, and Li.

M is at least one metal cation. Examples of the metal cation include metal cations selected from groups 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14 and 15. More preferably, cations such as Ag, Au, Bi, Ca, Ce, Co, Cr, Cu, Eu, Fe, Ga, Ge, Hf, In, Ir, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, Pb, Pd, Pt, Re, Rh, Ru, Sb, Sc, Sm, Sn, Sr, Ta, Te, Ti, V, W, Zn, and Zr are mentioned.

X is at least one kind of anion. Examples of the anion include chloride ion, bromide ion, iodide ion, cyanide ion and the like, and at least one kind of halogen is included.

a is 1 to 7, b is 1 to 4, and c is 3 to 16.

The emission wavelength (emission color) of these nanocrystal particles can be controlled by adjusting the particle size and the type and abundance of anions constituting the X-site.

The compound represented by the general formula A _a M _b X _c is 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 Compounds represented by 4 M 2 X 6 , A 3 MX 8 , A 3 M 2 X 9 , A 3 M 3 X 9 , A 2 M 2 X 10 , A 7 M 3 X 16 are} preferred.

In formula, A is at least 1 sort(s) of an organic cation and a metal cation. Examples of organic cations include ammonium, formamidinium, guanidinium, imidazolium, pyridinium, pyrrolidinium, and protonated thiourea. Examples of metal cations include cations such as Cs, Rb, K, Na, and Li.

In formula, M is at least 1 sort(s) of metal cation. Specifically, one type of metal cation (M ¹ ), two types of metal cations (M ¹ _α M ² _β ), three types of metal cations (M ¹ _α M ² _β M ³ _γ ), four types of metal cations (M ¹ _α M ² _β M ³ _γ M ⁴ _δ ) and the like are exemplified. However, α, β, γ, and δ represent real numbers of 0 to 1, respectively, and represent α+β+γ+δ = 1. Examples of the metal cation include metal cations selected from groups 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14 and 15. More preferably, cations such as Ag, Au, Bi, Ca, Ce, Co, Cr, Cu, Eu, Fe, Ga, Ge, Hf, In, Ir, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, Pb, Pd, Pt, Re, Rh, Ru, Sb, Sc, Sm, Sn, Sr, Ta, Te, Ti, V, W, Zn, and Zr are mentioned.

In formula, X is an anion containing at least 1 type of halogen. Specifically, one type of halogen anion (X ¹ ), two types of halogen anion (X ¹ _α X ² _β ), and the like are exemplified. Examples of the anion include chloride ion, bromide ion, iodide ion, cyanide ion and the like, and at least one kind of halogen is included.

The metal halide-containing compound represented by the general formula A _a M _b X _c may be one in which metal ions such as Bi, Mn, Ca, Eu, Sb, Yb, etc., different from the metal cation used at the M site are added (doped) to improve light emitting properties.

Among the metal halide-containing compounds represented by the general formula A _a M _b X _c , compounds having a perovskite-type crystal structure are particularly preferable for use as luminescent nanocrystals because the emission wavelength (emission color) can be controlled by adjusting the particle size, the type and abundance of metal cations constituting the M site, and the type and abundance of anions constituting the X site. Since this adjustment operation can be easily performed, perovskite-type semiconductor nanocrystals are characterized by easier control of emission wavelength and therefore higher productivity than conventional core-shell semiconductor nanocrystals. 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 may be doped with (doped) a metal ion such as Bi, Mn, Ca, Eu, Sb, or Yb that is different from the metal cation used for the M site.

Among the compounds exhibiting a perovskite-type crystal structure, it is preferable that A is Cs, Rb, K, Na, or Li, M is one metal cation (M ¹ ) or two metal cations (M ¹ _α M ² _β ), and X is a chloride ion, bromide ion, or iodide ion, in order to exhibit better light emitting characteristics. However, α and β represent real numbers of 0 to 1, respectively, and represent α+β=1. Specifically, M is preferably selected from Ag, Au, Bi, Cu, Eu, Fe, Ge, K, In, Na, Mn, Pb, Pd, Sb, Si, Sn, Yb, Zn, and Zr.

As a specific composition of the luminescent nanocrystal particles containing a metal halide exhibiting a perovskite-type crystal structure, nanocrystal particles using Pb as M such as CsPbBr ₃ , CH ₃ NH ₃ PbBr ₃ , CHN ₂ H ₄ PbBr ₃ etc. are preferable in terms of excellent light intensity and excellent quantum efficiency. In addition, nanocrystal particles using a metal cation other than Pb as M such as CsSnBr ₃ , CsEuBr ₃ , CsYbI ₃ , etc. are low in toxicity and have little effect on the environment.

The nanocrystal particles may be red luminescent crystals that emit light (red light) having an emission peak in the wavelength range of 605 to 665 nm, green luminescent crystals that emit light (green light) having an emission peak in the wavelength range of 500 to 560 nm, or blue luminescent crystals that emit light (blue light) having an emission peak in the wavelength range of 420 to 480 nm. In one embodiment, a combination of these nanocrystal particles may be used.

In addition, the wavelength of the emission peak of the nanocrystal particles can be confirmed in a fluorescence spectrum or phosphorescence spectrum measured using, for example, an absolute PL quantum yield measuring device.

The red luminescent nanocrystal particles have a wavelength range of 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, 632 nm or less, or 630 nm or less. It preferably has an emission peak at 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.

These upper limit and lower limit values can be combined arbitrarily. In addition, also in the same description below, the upper limit value and the lower limit value described individually can be combined arbitrarily.

The green luminescent nanocrystal particles preferably have an emission peak in a 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, 528 nm or more, 525 nm or more, 523 nm It is preferable to have an emission peak in a wavelength range of 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.

The blue luminescent nanocrystal particles preferably have an emission peak in a 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, 450 nm or more, 445 nm or more, 440 nm It is preferable to have an emission peak in a wavelength range of 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 particle is not particularly limited, and may be an arbitrary geometric shape or an arbitrary irregular shape. Examples of the shape of the nanocrystal particles include rectangular parallelepiped, cubic, spherical, tetrahedral, ellipsoidal, pyramidal, disk, branched, reticular, and rod shapes. Moreover, as a shape of a nanocrystal particle, a rectangular parallelepiped shape, a cubic shape, or a spherical shape is preferable.

The average particle diameter (volume average diameter) of the nanocrystal particles is preferably 40 nm or less, more preferably 30 nm or less, still more preferably 20 nm or less. In addition, the average particle diameter of the nanocrystal particles is preferably 1 nm or more, more preferably 1.5 nm or more, and still more preferably 2 nm or more. Nanocrystal particles having such an average particle diameter are preferable in that they easily emit light of a desired wavelength.

In addition, the average particle diameter of a nanocrystal particle is measured by a transmission electron microscope or a scanning electron microscope, and it is obtained by calculating a volume average diameter.

[surface layer]

It is preferable that the luminescent particle is a particle further provided with a surface layer formed on the surface of the nanocrystal particle. The surface layer preferably contains a polymer of a silane compound having an associative group capable of bonding to the surface of the semiconductor nanocrystal particle and a hydrolysable silyl group.

The binding group capable of bonding to the surface of the nanocrystal particle may be a binding group that binds (coordinates) to a cation contained in the nanocrystal particle. Examples of the bondable group include a carboxyl group, an amino group, an ammonium group, a mercapto group, a phosphine group, a phosphine oxide group, a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfonic acid group, and a boronic acid group. Especially, as a bondable group, it is preferable that it is at least 1 sort(s) of a carboxyl group, a mercapto group, and an amino group. These bondable groups have higher affinity for cations contained in the nanocrystal particles than the hydrolysable silyl groups described above. For this reason, the silane compound coordinates the bondable group toward the nanocrystal particle side, so that the nanocrystal particle having a surface layer can be formed more easily and reliably.

A silane compound is formed by reaction of precursor compounds which have a bondable group and a hydrolyzable silyl group. A hydrolysable silyl group can easily form a siloxane bond. As a hydrolysable silyl group, a silanol group and a C1-C6 alkoxysilyl group are preferable.

As a precursor compound, the silane compound which has a bondable group and a hydrolysable silyl group may be used individually by 1 type, or may be used in combination of 2 or more types.

The precursor compound may contain one or two 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 3-(trimethoxysilyl)propionic acid, 3-(triethoxysilyl)propionic acid, 2-,carboxyethylphenylbis(2-methoxyethoxy)silane, N-[3-(trimethoxysilyl)propyl]-N'-carboxymethylethylenediamine, N-[3-(trimethoxysilyl)propyl]phthalamide, and 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, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldipropoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiisopropoxy Silane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltripropoxysilane, 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)phenyltrimethoxy Cisilane, (aminoethylaminoethyl)phenyltriethoxysilane, (aminoethylaminoethyl)phenyltripropoxysilane, (aminoethylaminoethyl)phenyltriisopropoxysilane, (aminoethylaminomethyl)phenyltrimethoxysilane, (aminoethylaminomethyl)phenyltriethoxysilane, (aminoethylaminomethyl)phenyltripropoxysilane, (aminoethylaminomethyl)phenyltriisopropoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-amino Propyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropylmethyldimethoxysilane, 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, benzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltriethoxysilane, 3-ureidpropyltriethoxysilane, 3-(N-phenyl)aminopropyltrimethoxysilane, N,N-bis[3-(trimethoxysilyl) propyl] ethylenediamine, (aminoethylaminoethyl)phenethyltrimethoxysilane, (aminoethylaminoethyl)phenethyltriethoxysilane, (aminoethylaminoethyl)phenethyltripropoxysilane, (aminoethylaminoethyl)phenethyltriisopropoxysilane, (aminoethylaminomethyl)phenethyltrimethoxysilane, (aminoethylaminomethyl)phenethyltriethoxysilane, (aminoethylaminomethyl)phenethyltripropoxysilane, (aminoethyl aminomethyl) phenethyltriisopropoxysilane, N-[2-[3-(trimethoxysilyl)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.

Specific examples of the silicon compound containing a mercapto group include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 2-mercaptoethylmethyldimethoxysilane, and 2-mercaptoethyldimethoxysilane. toethylmethyl diethoxysilane, 3-[ethoxybis(3,6,9,12,15-pentaoxaoctacosan-1-yloxy)silyl]-1-propanethiol, and the like.

It is preferable that it is 0.5-50 nm, and, as for the thickness of a surface layer, it is more preferable that it is 1.0-30 nm. If it is a luminescent particle having a surface layer having such a thickness, the stability of the nanocrystal particle against heat can be sufficiently increased.

In addition, the thickness of the surface layer can be changed by adjusting the number of atoms (chain length) of the linkage structure linking the bondable group and the hydrolysable silyl group of the precursor compound.

The surface layer can be formed by a method comprising mixing a solution containing the raw material compound of the nanocrystal particle and a solution containing the precursor compound, and then condensing a hydrolyzable silyl group coordinated on the surface of the precipitated nanocrystal particle.

[hollow particles]

The luminescent particles may further include hollow particles having an inner space accommodating the nanocrystal particles and pores communicating with the inner space. By accommodating the nanocrystal particles inside the hollow particles, the stability of the luminescent particles against oxygen gas and moisture can be further improved.

The hollow particles may have a spherical shape (real spherical shape), an elongated spherical shape (elliptic 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.

In the inner space, one nanocrystal particle may exist, or a plurality of nanocrystal grains may exist. In addition, the whole inner space may be occupied by one or a plurality of nanocrystal particles, or only a part may be occupied.

As the hollow particle, any material may be used as long as it can protect the nanocrystal particle. From the viewpoint of ease of synthesis, transmittance, cost, etc., the hollow particles are preferably hollow silica particles, hollow alumina particles, hollow titanium oxide particles, or hollow polymer particles, more preferably hollow silica particles or hollow alumina particles, and still more preferably hollow silica particles.

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, still more preferably 8 to 50 nm, and particularly preferably 10 to 25 nm. 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 particularly preferably 5 to 15 nm. If it is a hollow particle of such a size, the stability of the nanocrystal particle against heat can be sufficiently increased.

Although the size of a pore is not specifically limited, It is preferable that it is 0.5-10 nm, and it is more preferable that it is 1-5 nm. In this case, the inner space can be smoothly and reliably filled with a solution containing the raw material compound of the nanocrystal particles.

A commercial item can also be used for hollow silica particles. As such a commercial item, "SiliNax (registered trademark) SP-PN(b)" by Nippon Industries, Ltd., etc. is mentioned, for example. In addition to stabilizing the semiconductor nanocrystal particles, the hollow particles are preferably hollow silica particles from the viewpoint of luminescent properties and dispersing properties to ink and the like.

For example, by impregnating the hollow particle with a solution containing the raw material compound of the nanocrystal particle and drying the nanocrystal particle to precipitate in the inner space of the hollow particle, the nanocrystal particle is accommodated in the inner space of the hollow particle.

[Polymer layer]

The luminescent particles may further contain a polymer layer containing a hydrophobic polymer. The polymer layer may be located on the outermost layer of the luminescent particles containing nanocrystal particles. For example, when the luminescent particles have a surface layer, the polymer layer may be a layer covering at least a part of the surface layer. When the luminescent particles contain hollow silica, the polymer layer may be a layer covering at least a part of the hollow silica. When the nanocrystal particles have a polymer layer, high stability against oxygen and moisture can be imparted to the luminescent particles. In addition, when an ink composition is prepared using luminescent particles having a polymer layer, the dispersion stability of the luminescent particles can also be improved. If the polymer layer is included, it tends to be difficult for the luminescent particles to agglomerate when the ink composition is prepared, making it difficult for the luminescent properties to deteriorate due to 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 the 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 a non-aqueous solvent capable of uniformly dispersing the mother particles. By using such a non-aqueous solvent, the hydrophobic polymer can be adsorbed onto the mother particles very simply to coat the polymer layer. Also, preferably, the non-aqueous solvent is a low dielectric constant solvent. By using a low dielectric constant solvent, the hydrophobic polymer is firmly adsorbed on the surface of the parent particle and the polymer layer can be coated simply by mixing the hydrophobic polymer and the parent particle in the non-aqueous solvent.

The polymer layer obtained in this way is difficult to be removed from the mother particles even if the luminescent particles are washed with a solvent. In addition, the dielectric constant of the non-aqueous solvent is so preferable that it is low. 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. As a preferable non-aqueous solvent, it is preferable that it is an organic solvent containing at least one of an aliphatic hydrocarbon type solvent and an alicyclic hydrocarbon type solvent.

Examples of the aliphatic hydrocarbon-based solvent or alicyclic hydrocarbon-based solvent include n-hexane, n-heptane, n-octane, cyclopentane, and cyclohexane.

A mixed solvent obtained by mixing another organic solvent with at least one of an aliphatic hydrocarbon-based solvent and an alicyclic hydrocarbon-based solvent may be used as the non-aqueous solvent within a range not impairing the effects of the present invention. Examples of such other organic solvents include aromatic hydrocarbon-based solvents such as toluene and xylene; ester solvents such as methyl acetate, ethyl acetate, n-butyl acetate, and amyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, and cyclohexanone; and alcohol solvents such as methanol, ethanol, n-propanol, i-propanol, and n-butanol.

When used as a mixed solvent, the amount of at least one of the aliphatic hydrocarbon-based solvent and the alicyclic hydrocarbon-based solvent used is preferably 50% by mass or more, and more preferably 60% by mass or more.

[Polymer (P)]

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

As the alkyl (meth) acrylate (A), for example, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, di Cyclopentenyl (meth)acrylate and dicyclopentanyl (meth)acrylate are mentioned. Here, in this 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), acrylates represented by the following formulas (B1-8) to (B1-15), and the like. In addition, these compounds may be used individually by 1 type, and may use 2 or more types together.

Moreover, as a fluorine-containing compound (C) which has a polymerizable unsaturated group, the poly(perfluoroalkylene ether) chain and the compound which has a polymerizable unsaturated group at both ends are mentioned, for example.

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, as the fluorine-containing compound (C), a compound represented by the formula (C-1), (C-2), (C-5) or (C-6) is preferable because of its easy industrial production, and a compound having acryloyl groups at both ends of the poly(perfluoroalkylene ether) chain represented by the formula (C-1), or a poly(perfluoroalkylene ether) chain represented by the formula (C-1), from the viewpoint of being able to synthesize a polymer (P) that is easily entangled on the surface of the parent particle A compound having methacryloyl groups at both ends of the fluoroalkylene ether chain is more preferable.

Examples of compounds other than the alkyl (meth)acrylate (A) and fluorine-containing compounds (B, C) as the polymer (P) include aromatic vinyl compounds such as styrene, α-methylstyrene, p-t-butylstyrene, and vinyltoluene; (meth)acrylate compounds such as benzyl (meth)acrylate, dimethylamino (meth)acrylate, diethylamino (meth)acrylate, dibromopropyl (meth)acrylate, and tribromophenyl (meth)acrylate; diester compounds of unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid with monohydric alcohols; vinyl benzoate; vinyl ester compounds such as “Veova (registered trademark)” (vinyl ester manufactured by Shell, Netherlands); and the like.

It is preferable to use these compounds 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 improved.

The compounds usable as the polymer (P) may be used individually by 1 type, or may use 2 or more types together. Among them, it is preferable to use an 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.

Polymer (P) is obtained by polymerizing these compounds by a conventional method to obtain a copolymer of the compound, and then introducing a polymerizable unsaturated group into the copolymer.

As a method for introducing a polymerizable unsaturated group, for example, as a copolymerization component, a carboxylic acid group-containing polymerizable monomer such as acrylic acid or methacrylic acid, an amino group-containing polymerizable monomer such as dimethylaminoethyl methacrylate or dimethylaminopropyl acrylamide are blended and copolymerized in advance to obtain a copolymer having a carboxylic acid group or amino group, and then reacting the carboxylic acid group or amino group with a monomer having a glycidyl group such as glycidyl methacrylate and a polymerizable unsaturated group. way can be

[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. As the monomer (M), for example, vinyl monomers having no reactive polar group (functional group), vinyl monomers containing an amide bond, (meth)acryloyloxyalkyl phosphates, (meth)acryloyloxyalkyl phosphites, phosphorus atom-containing vinyl monomers, hydroxyl group-containing polymerizable unsaturated monomers, dialkylaminoalkyl (meth)acrylates, epoxy group-containing polymerizable unsaturated monomers, isocyanate group-containing α,β-ethylenically unsaturated monomers, alkoxy silyl group-containing polymerizable unsaturated monomers, carboxyl group-containing α,β-ethylenically unsaturated monomers, and the like.

Specific examples of vinyl monomers having no reactive polar group include (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and i-propyl (meth)acrylate, and olefins such as (meth)acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride.

Specific examples of the amide bond-containing vinyl monomers include (meth)acrylamide, dimethyl(meth)acrylamide, N-t-butyl(meth)acrylamide, N-octyl(meth)acrylamide, diacetone acrylamide, dimethylaminopropyl acrylamide, and alkoxylated N-methylolated (meth)acrylamides.

Specific examples of (meth)acryloyloxyalkyl phosphates include dialkyl[(meth)acryloyloxyalkyl] phosphates and (meth)acryloyloxyalkyl acid phosphates.

Specific examples of (meth)acryloyloxyalkyl phosphites include dialkyl[(meth)acryloyloxyalkyl] phosphites and (meth)acryloyloxyalkyl acid phosphites.

Specific examples of the phosphorus atom-containing vinyl monomers include, for example, (meth)acryloyloxyalkyl acid phosphates or alkylene oxide adducts of (meth)acryloyloxyalkyl acid phosphites, ester compounds of epoxy group-containing vinyl monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate with phosphoric acid, phosphorous acid or these acid esters, 3-chloro-2-acid phosphoxypropyl (meth)acrylate, etc. can be heard

Specific examples of the hydroxyl group-containing polymerizable unsaturated monomers include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, di-2-hydroxyethyl fumarate, and mono-2-hydroxy. hydroxyalkyl esters of polymerizable unsaturated carboxylic acids such as ethyl monobutyl fumarate, polypropylene glycol mono(meth)acrylate, and polyethylene glycol mono(meth)acrylate, or adducts thereof with ε-caprolactone; polymerizable unsaturated carboxylic acids such as unsaturated mono- or dicarboxylic acids such as (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid, and monoesters of dicarboxylic acids and monohydric alcohols; Monoglycidyl of monovalent carboxylic acids and various unsaturated carboxylic acids such as adducts of hydroxyalkyl esters of the above polymerizable unsaturated carboxylic acids with anhydrides of polycarboxylic acids (maleic acid, succinic acid, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, benzene tricarboxylic acid, benzene tetracarboxylic acid, "hymic acid", tetrachlorphthalic acid, dodecinyl succinic acid, etc.) esters (coconut oil fatty acid glycidyl ester, octylic acid glycidyl ester, etc.), butyl glycidyl ether, ethylene oxide, and adducts of monoepoxy compounds such as propylene oxide, or adducts of these with ε-caprolactone; Hydroxy vinyl ether etc. are mentioned.

As a specific example of dialkylaminoalkyl (meth)acrylates, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, etc. are mentioned, for example.

Specific examples of the epoxy group-containing polymerizable unsaturated monomers include, for example, polymerizable unsaturated carboxylic acids, hydroxyl group-containing vinyl monomers and polycarboxylic acid anhydride equimolar adducts (mono-2-(meth)acryloyloxy monoethyl phthalate, etc.), epoxy group-containing polymerizable compounds obtained by addition reaction of various polyepoxy compounds having at least two epoxy groups in one molecule in an equimolar ratio to various unsaturated carboxylic acids, such as glycidyl (meth)acrylic acid. rate, (β-methyl) glycidyl (meth)acrylate, (meth)aryl glycidyl 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, an isocyanate group such as isocyanate ethyl (meth)acrylate, and a monomer having a vinyl group, and the like.

Specific examples of the alkoxysilyl group-containing polymerizable unsaturated monomers include silicone monomers such as vinylethoxysilane, α-methacryloxypropyltrimethoxysilane, and trimethylsiloxyethyl (meth)acrylate.

Specific examples of the carboxyl group-containing α,β-ethylenically unsaturated monomers include, for example, (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, unsaturated mono- or dicarboxylic acids such as citraconic acid, α,β-ethylenically unsaturated carboxylic acids such as monoesters of dicarboxylic acids and monohydric alcohols; 2-Hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl-monobutyl fumarate, polyethylene glycol mono (meth) acrylate and adducts of α,β-unsaturated carboxylic acid hydroalkyl esters such as late with polycarboxylic acid anhydrides such as maleic acid, succinic acid, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, benzene tricarboxylic acid, benzene tetracarboxylic acid, “hymic acid”, tetrachlorphthalic acid, and dodecinyl succinic acid.

Especially, as a monomer (M), it is preferable that it is an alkyl (meth)acrylate which has a C3 or less alkyl group like methyl (meth)acrylate and ethyl (meth)acrylate.

The polymer layer is formed by polymerizing the monomer (M) in the presence of the mother particles, a non-aqueous solvent and the polymer (P).

It is preferable to mix the mother particles and the polymer (P) before polymerization. For mixing, a homogenizer, a disper, a bead mill, a paint shaker, a kneader, a roll mill, a ball mill, an attritor, a sand mill or the like can be used, for example.

The form of the mother particle used when forming the polymer layer is not particularly limited, and any of slurry, wet cake, powder and the like may be used.

After mixing the mother particles and the polymer (P), the monomer (M) and a polymerization initiator described later are further mixed to perform polymerization, thereby forming a polymer layer composed of a polymer of the polymer (P) and the monomer (M). In this way, 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, still more preferably 3,000 to 100,000. By using the polymer (P) having a molecular weight within this range, the surface of the mother particle can be satisfactorily coated with the polymer layer.

The amount of the polymer (P) used is appropriately set depending on the purpose, so it is not particularly limited, but is usually preferably 0.5 to 50 parts by mass, more preferably 1 to 40 parts by mass, still more preferably 2 to 35 parts by mass, based on 100 parts by mass of the mother particles.

In addition, since the amount of monomer (M) is appropriately set depending on the purpose, it is not particularly limited, but is usually preferably 0.5 to 40 parts by mass, more preferably 1 to 35 parts by mass, still more preferably 2 to 30 parts by mass, based on 100 parts by mass of the mother particles.

The amount of the hydrophobic polymer that finally coats the surface of the mother particles is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and still more preferably 3 to 40 parts by mass, based on 100 parts by mass of the mother particles.

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, still more preferably 50 to 80 parts by mass, based on 100 parts by mass of the polymer (P).

The thickness of the polymer layer is preferably 0.5 to 100 nm, more preferably 0.7 to 50 nm, and still more preferably 1 to 30 nm. When the thickness of the polymer layer is less than 0.5 nm, dispersion stability is often not obtained. When the thickness of the polymer layer exceeds 100 nm, it is often difficult to contain the mother particles at a high concentration. By covering the mother particles with a polymer layer having such a thickness, the stability of the luminescent particles against oxygen and moisture can be further improved.

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), benzoyl peroxide, t-butyl perbenzoate, t-butyl-2-ethylhexanoate, t-butyl hydroperoxide, di-t-butyl peroxide, and cumene hydroperoxy. de, etc. These polymerization initiators may be used individually by 1 type, and may use 2 or more types together.

The polymerization initiator sparingly soluble in non-aqueous solvents is preferably added to the liquid mixture containing the mother particles and the polymer (P) in a dissolved state in the monomer (M).

In addition, the monomer (M) or the monomer (M) in which the polymerization initiator is dissolved may be added dropwise to the mixed solution having reached the polymerization temperature for polymerization, but it is stable and preferably added to the mixed solution at normal temperature before the temperature is raised, mixed sufficiently, and then heated to polymerize.

The polymerization temperature is preferably in the range of 60 to 130°C, and more preferably in the range of 70 to 100°C. When the polymerization of the monomer (M) is carried out at such a polymerization temperature, the shape change (eg, alteration, crystal growth, etc.) of the nanocrystal particles can be suitably prevented.

After polymerization of the monomer (M), the polymer not adsorbed on the surface of the mother particle is removed to obtain the luminescent particle. Centrifugal sedimentation and ultrafiltration are examples of methods for removing non-adsorbed polymers. In centrifugal sedimentation, the dispersion containing the parent particles and the non-adsorbed polymer is rotated at high speed to cause the parent particles in the dispersion to settle, thereby separating the non-adsorbed polymer. In ultrafiltration, a dispersion containing the mother particles and the unadsorbed 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. In the above manner, luminescent particles having a polymer layer are obtained. The luminescent particles may be stored in a dispersed state in a dispersion medium or photopolymerizable compound (that is, as a dispersion liquid), or may be stored as a powder (aggregate of luminescent particles alone) after removing the dispersion medium.

[Content of luminescent particles]

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 or less. By setting the content of the luminescent particles within the above range, the ejection stability can be further improved when the ink composition is ejected by the inkjet printing method. In addition, it becomes difficult for the luminescent particles to aggregate with each other, and the external quantum efficiency of the resulting luminescent layer (light conversion layer) can be increased.

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

<<NOR type hindered amine compound>>

The ink composition contains a NOR-type hindered amine compound represented by the following formula (1). The hindered amine compound is a compound having an imino group (NOR-type hindered amino group) in which a hydrocarbon group (R) is bonded via an oxygen atom (O) as a hindered amino group. The NOR-type hindered amine compound may be a compound having one NOR-type hindered amino group, or a compound having a plurality of (eg, two or more) NOR-type hindered amino groups. In addition, the ink composition may use only 1 type as a NOR-type hindered amine compound, and may use 2 or more types.

[In Formula (1), R ¹ to R ⁵ each independently represent a hydrocarbon group, and * represents a bond.]

The number of carbon atoms of the hydrocarbon group as R ¹ and R ⁴ is, for example, 1 or more or 2 or more, and preferably 8 or less or 7 or less. It is preferable that R ^<1> is a C1-C50 alkyl group, a C5-C12 cycloalkyl group, a C7-C25 aralkyl group, or a C6-C12 aryl group, for example. The alkyl group may be linear or branched. The cycloalkyl group may be, for example, a cyclohexyl group.

The hydrocarbon group as R ² to R ⁵ and R ⁶ to R ¹⁰ may be, for example, an alkyl group. The number of carbon atoms in the hydrocarbon group as R ² to R ⁵ may be, for example, 1 or more and 8 or less. R ² to R ⁵ may be, for example, a methyl group.

* represents a bond, and may be, for example, a bonding site with a carbon atom, a nitrogen atom, or an oxygen atom.

Since the ink composition of the present embodiment contains the NOR-type hindered amine compound represented by the above formula (1), it is possible to form a cured film having excellent solubility to the photopolymerizable compound in the ink composition and excellent light resistance under high temperature, compared to the case of containing the NR-type hindered amine compound. The photopolymerizable compound used as the ink composition is preferably a compound with low polarity from the viewpoint of compatibility with light emitting particles, and use of a NOR-type hindered amine compound is more preferable. In addition, compared to NR-type hindered amine compounds, NOR-type hindered amine compounds are less likely to be coordinated to the surface of semiconductor nanocrystals, etc., and the photostabilizing action of the hindered amine compounds is not inhibited, so it is presumed to have excellent light resistance. In addition, an NR type hindered amine compound means a structure represented by "-N-R" instead of the structure represented by "-N-O-R" of a NOR type hindered amine compound, and R is hydrogen or an alkyl group.

The NOR type hindered amine compound may be a compound further having a 1,3,5-triazine ring which may have a substituent. For example, the structure represented by Formula (1) may be bonded to the 1,3,5-triazine ring directly or via another atom (eg, nitrogen atom).

As the NOR-type hindered amine compound, for example, a liquid at 20°C or a solid at 20°C may be used. However, considering that the cured product of the ink composition may be heated to, for example, about 50° C. with light irradiation, the melting point of the NOR-type hindered amine compound is preferably higher, and is preferably 70° C. or higher, 80° C. or higher, or 85° C. or higher. When a NOR-type hindered amine compound having a melting point of 70° C. or higher is used, even when a cured product of the ink composition is heated to a high temperature of about 50° C., liquefaction of the hindered amine compound does not occur, and therefore, a phenomenon in which the hindered amine compound bleeds out to the surface of the cured product (bleed phenomenon) can be prevented from occurring (bleed resistance). On the other hand, considering the solubility in the ink composition, the NOR-type hindered amine compound preferably has a melting point of 180°C or less.

The molecular weight (or molar mass) or mass average molecular weight of the NOR-type hindered amine compound may be 1000 or more. In this specification, "mass average molecular weight" can employ the value measured using gel permeation chromatography (GPC) using polystyrene as a standard substance. If the molecular weight or mass average molecular weight is within the above range, since the melting point is high, bleed resistance in a high-temperature environment can be obtained reliably, and light resistance becomes further excellent.

The NOR-type hindered amine compound is preferably a compound represented by, for example, the following formula (1a), the following formula (1b), the following formula (1c), the following formula (1d), or the following formula (1e). From the viewpoint of further excellent curability and further excellent light resistance under high temperature, it is more preferable that the NOR-type hindered amine compound is a compound represented by the following formula (1a) or the following formula (1b).

[In Formula (1a), n represents an integer of 1 to 15.]

[In formula (1b), R is the following formula (1b-R):

represents the group represented by In formula (1b-R), * represents a bonding site with a nitrogen atom.]

Commercially available NOR-type hindered amine compounds include, for example, TINUVIN (registered trademark) NOR371 (melting point: 91 to 104° C., mass average molecular weight: 2800 to 4000, manufactured by BASF Japan Co., Ltd.) having a structure represented by the formula (1a), and Flamestab NOR116FF having a structure represented by the formula (1b) (melting point: 108 to 12 3 ° C, molecular weight: 2261, manufactured by BASF Japan Co., Ltd.), TINUVIN (registered trademark) 123 (melting point < 20 ° C. (liquid phase), molecular weight: 737, manufactured by BASF Japan Co., Ltd.) having a structure represented by the above formula (1c), LA-81 (melting point < 20 ° C. (liquid phase), molecular weight 681, manufactured by BASF Japan Corporation) having a structure represented by the above formula (1d) ADEKA), and TINUVIN (registered trademark) 152 (melting point: 83 to 90°C, molecular weight: 757, manufactured by BASF Japan Co., Ltd.) having a structure represented by the above formula (1e).

The content of the NOR-type hindered amine compound may be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more based on the total mass of the ink composition from the viewpoint of further improving light resistance at high temperatures. The content of the NOR-type hindered amine compound may be, for example, 5.0% by mass or less, 3.0% by mass or less, or 2.0% by mass or less.

<<Photopolymerizable Compounds>>

The ink composition contains a photopolymerizable compound. The photopolymerizable compound is preferably a radical photopolymerizable compound that polymerizes by irradiation with light, and may be a photopolymerizable monomer or oligomer. These are used together with a photoinitiator. A photopolymerizable compound may be used individually by 1 type, and may use 2 or more types together.

The photopolymerizable compound preferably contains a monofunctional monomer having one photopolymerizable group and a polyfunctional monomer having two or more photopolymerizable groups. The mass ratio of the monofunctional monomer to the polyfunctional monomer in the photopolymerizable compound may be 1.0, 5.0 or 10.0. When the mass ratio of the monofunctional monomer to the polyfunctional monomer is within this range, the cured film (light conversion layer) has further excellent light emitting properties in that the ink viscosity is suitable for inkjet compatibility and the cured film has excellent curability.

Examples of the photopolymerizable compound (radical photopolymerizable compound) include (meth)acrylate compounds. The (meth)acrylate compound includes a methacrylate compound having a methacryloyl group and an acrylate compound having an acryloyl group.

The (meth)acrylate compound may be a monofunctional (meth)acrylate having one (meth)acryloyl group or a polyfunctional (meth)acrylate having a plurality of (meth)acryloyl groups. From the viewpoint of excellent fluidity when preparing the ink composition, the viewpoint of further excellent discharge stability, and the viewpoint of suppressing the decrease in smoothness due to curing shrinkage during cured film production, it is preferable to use a combination of monofunctional (meth) acrylate and polyfunctional (meth) acrylate.

As the monofunctional (meth)acrylate, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, methoxy Cyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (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 (meth) acrylate, phenyl benzyl (meth) acrylate, mono (2-acryloyloxyethyl) succinate, N- [2- (acryloyloxy) ethyl] phthalimide, N- [2- (acryloyloxy) ethyl] tetrahydrophthalimide and the like.

The polyfunctional (meth)acrylate may be bifunctional (meth)acrylate, trifunctional (meth)acrylate, tetrafunctional (meth)acrylate, pentafunctional (meth)acrylate, or hexafunctional (meth)acrylate, for example, di(meth)acrylate in which two hydroxyl groups of a diol compound are substituted by (meth)acryloyloxy groups, di(meth)acrylate in which two or three hydroxyl groups of a triol compound are substituted by (meth)acryloyloxy groups, or Tri(meth)acrylate etc. may be sufficient.

Specific examples of the bifunctional (meth)acrylate include 1,3-butylene glycoldi(meth)acrylate, 1,4-butanedioldi(meth)acrylate, 1,5-pentanedioldi(meth)acrylate, 3-methyl-1,5-pentanedioldi(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, neopentylglycoldi(meth)acrylate, and 1,8-octanedioldi(meth)acrylate. Acrylate, 1,9-nonanedioldi(meth)acrylate, tricyclodecanedimethanoldi(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol hydroxypivalic acid ester diacrylate, tris(2-hydroxyethyl) Di(meth)acrylate in which two hydroxyl groups of isocyanurate are substituted by (meth)acryloyloxy groups, di(meth)acrylate in which two hydroxyl groups of a diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol are substituted by (meth)acryloyloxy groups, and two hydroxyl groups of a diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A. ) di(meth)acrylate substituted by acryloyloxy group, di(meth)acrylate in which two hydroxyl groups of triol obtained by adding 3 or more ethylene oxide or propylene oxide to 1 mol of trimethylolpropane are substituted by (meth)acryloyloxy group, di(meth)acrylate in which two hydroxyl groups of diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A are substituted by (meth)acryloyloxy group A rate etc. are mentioned.

Specific examples of the trifunctional (meth)acrylate include, for example, trimethylolpropane tri(meth)acrylate, glycerin triacrylate, pentaerythritol tri(meth)acrylate, and tri(meth)acrylate in which three hydroxyl groups of a triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane are substituted with (meth)acryloyloxy groups.

As a specific example of tetrafunctional (meth)acrylate, pentaerythritol tetra (meth)acrylate etc. are mentioned, for example.

As a specific example of a pentafunctional (meth)acrylate, dipentaerythritol penta (meth)acrylate etc. are mentioned, for example.

As a specific example of 6 functional (meth)acrylate, dipentaerythritol hexa(meth)acrylate etc. are mentioned, for example.

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 ethylene oxide-modified phosphoric acid (meth)acrylate or ethylene oxide-modified alkyl phosphoric acid (meth)acrylate having a phosphoric acid group.

In the ink composition, when the curable component is composed of only a photopolymerizable compound or a photopolymerizable compound as a main component, as the photopolymerizable compound as described above, it is more preferable to use a bifunctional or higher polyfunctional photopolymerizable compound having two or more polymerizable functional groups in one molecule as an essential component in view of further increasing the durability (strength, heat resistance, etc.) of the cured product.

In addition, from the viewpoint of excellent viscosity stability when preparing the ink composition, the viewpoint of further excellent discharge stability, and the viewpoint of suppressing the decrease in smoothness of the cured film due to cure shrinkage during production of the cured film, it is preferable to use a combination of monofunctional (meth) acrylate and polyfunctional (meth) acrylate.

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. It is preferably 50 to 500, more preferably 100 to 400, from the viewpoint of easy compatibility of the viscosity as inkjet ink and the volatility of the ink after ejection.

As the photopolymerizable compound, when combining monofunctional (meth)acrylate and polyfunctional (meth)acrylate, the monofunctional (meth)acrylate has a viscosity of, for example, 2 mPa s or more, 3 mPa s or more, or 5 mPa s or more. The viscosity of monofunctional (meth)acrylate is, for example, 50 or less, and may be 20 or less or 10 or less. It is preferably 2 to 50 mPa·s, more preferably 3 to 20 mPa·s, and particularly preferably 5 to 10 mPa·s, from the viewpoint of easy compatibility of viscosity as an inkjet ink, dischargeability and viscosity stability.

Examples of monofunctional (meth)acrylate compounds having a viscosity of 2 to 50 mPa s at room temperature include lauryl acrylate (viscosity 4 to 5 mPa s), isostearyl acrylate (viscosity 17 mPa s, viscosity 4 to 5 mPa s), isodecyl acrylate (viscosity 2.7 mPa s), isobornyl acrylate (viscosity 7.7 mPa s), cyclohexyl acrylate ( viscosity 2.5 mPa s), benzyl acrylate (viscosity 2.2 mPa s), phenoxyethyl acrylate (viscosity 9 mPa s), dicyclopentenyl acrylate (viscosity 8 to 18 mPa s), dicyclopentenyloxyethyl acrylate (viscosity 15 to 25 mPa s), dicyclopentanyl acrylate (viscosity 7 to 17 mPa s), (2-methyl-2-ethyl -1,3-dioxolan-4-yl)methyl acrylate (viscosity 5.1 mPa s), tetrahydrofurfuryl acrylate (viscosity 2.8 mPa s), 5-ethyl-1,3-dioxan-5-yl methyl acrylate (viscosity 10.0 mPa s), 2-ethylhexyl acrylate (viscosity 2 mPa s), 2-[2-(ethoxy)ethoxy]ethyl acrylate (viscosity 4 to 5 mPa s), methoxytriethylene glycol acrylate (viscosity 5 to 6 mPa s), 2-ethylhexyl carbitol acrylate (viscosity 4 to 5 mPa s), methoxy polyethylene glycol #400 acrylate (viscosity 25 to 30 mPa s), methoxydipropylene glycol acrylate (viscosity 2 to 3 mPa s), lauryl methacrylate ( viscosity 5 mPa s), tert-butyl methacrylate (viscosity 2 mPa s), 2-ethylhexyl methacrylate (viscosity 3 mPa s), isodecyl methacrylate (viscosity 5 mPa s), isobornyl methacrylate (viscosity 6 mPa s), cyclohexyl methacrylate (viscosity 2 to 4 mPa s), benzyl methacrylate (viscosity 2 to 4 mPa s), phenoxyethyl methacrylate (viscosity 7 mPa s), dicyclopentenyloxyethyl methacrylate (viscosity 15 to 20 mPa s), dicyclopentanyl methacrylate (viscosity 7 to 17 mPa s), and the like.

From the viewpoint of reducing stickiness (tack) on the surface of a cured product of an 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 is preferably 3 or less. The number of carbon atoms constituting the cyclic structure is, for example, 4 or more, preferably 5 or more or 6 or more. The number of carbon atoms is, for example, 20 or less, and preferably 18 or less.

It is preferable that an aromatic ring structure is a structure which has a C6-C18 aromatic ring. As a C6-C18 aromatic ring, a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, etc. are mentioned. The aromatic ring structure may be a structure having an aromatic heterocycle. As an aromatic heterocycle, a furan ring, a pyrrole ring, a pyran ring, a pyridine ring etc. are mentioned, for example. 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 in which two or more aromatic rings are bonded through a single bond (for example, a biphenyl structure).

It is preferable that a non-aromatic ring structure is a structure which has a C5-C20 alicyclic ring, for example. 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, and a cycloalkene ring such as a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, and a cyclooctene ring. The alicyclic ring may be a condensed ring such as a bicyclo undecane 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. As a non-aromatic heterocycle, a tetrahydrofuran ring, a pyrrolidine ring, a tetrahydropyran ring, a pipericine ring etc. are mentioned, for example.

The radically polymerizable compound having a cyclic structure is preferably a monofunctional or polyfunctional (meth)acrylate having a cyclic structure, 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 preferably used.

The content of the radically polymerizable compound having a cyclic structure is preferably 3 to 85% by mass, more preferably 10 to 80% by mass, and still more preferably 20 to 75% by mass, based on the total mass of the photopolymerizable compound in the ink composition, from the viewpoint of easily suppressing stickiness (tack) on the surface of the ink composition, easy to obtain an appropriate viscosity as an inkjet ink, and easy to obtain excellent ejection properties, 30 to 70% by mass is particularly preferred.

From the viewpoint of easily obtaining excellent discharge properties, it is preferable to use a radically polymerizable compound having a linear structure with 3 or more carbon atoms as the ink composition, and more preferably a radically polymerizable compound with a linear structure with 4 or more carbon atoms. 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 is preferably 3 or less. The radically polymerizable compound having a straight chain structure having 4 or more carbon atoms is preferably a structure in which the straight chain structure is connected without breaking off atoms other than hydrogen atoms, and may have heteroatoms such as oxygen atoms in addition to carbon atoms and hydrogen atoms. That is, the linear structure is not limited to a structure in which three or more carbon atoms continue in a straight chain, and a structure in which three or more carbon atoms are connected in a straight chain through a hetero atom such as an oxygen atom may be used. The linear structure may have an unsaturated bond, but preferably contains only a saturated bond. The number of carbon atoms constituting the linear structure is preferably 5 or more, more preferably 6 or more, still more 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, a radically polymerizable compound having a linear structure in which the total number of carbon atoms is 3 or more (the number does not include carbon atoms of a methyl group or an ethyl group in which hydrogen atoms directly connected to carbon atoms forming the linear structure are substituted). From the viewpoint of ejection properties, it is preferable not to have a cyclic structure.

It is preferable that a linear structure is a structure which has a C4 or more linear alkyl group, for example. Examples of the straight chain 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. As the radically polymerizable compound having such a structure, an alkyl (meth)acrylate obtained by directly bonding the straight-chain alkyl group to a (meth)acryloyloxy group is preferably used.

It is preferable that a linear structure is a structure which has a C4 or more linear alkylene group, for example. Examples of the straight-chain alkylene group having 4 or more carbon atoms include butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, and pentadecylene. As the radically polymerizable compound having such a structure, an alkylene glycol di(meth)acrylate obtained by bonding two (meth)acryloyloxy groups to the straight-chain alkylene group is preferably used.

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

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

As the photopolymerizable compound, from the viewpoint of excellent uniformity of the surface of the pixel portion, it is preferable to use two or more types of radically polymerizable compounds, and it is more preferable to use a combination of a radically polymerizable compound having a cyclic structure and a radically polymerizable compound having a linear structure having 3 or more carbon atoms described above. In order to improve the external quantum efficiency, when the amount of nanocrystal particles containing luminescent nanocrystals is increased, the uniformity of the surface of the pixel portion may decrease, but even in this case, the combination of the photopolymerizable compound tends to provide a pixel portion with excellent surface uniformity.

The SP value of the photopolymerizable compound is preferably 10.0 or less. The SP value of the photopolymerizable compound may be, for example, 9.75 or less or 9.50 or less, or 8.50 or more or 8.70 or more. When the SP value is within the above range, the solubility of the NOR-type hindered amine compound, the storage stability of the ink, and the optical properties (eg, external quantum efficiency) are further excellent.

When the ink composition of the present invention contains a photopolymerizable compound having an SP value of 10.0 or less, the content of the photopolymerizable compound is preferably 0 to 15% by mass, more preferably 0 to 10% by mass, more preferably 0 to 10% by mass, and preferably 0 to 5% by mass, based on the total mass of the photopolymerizable compound in the ink composition, from the viewpoint of obtaining excellent ink storage stability and excellent optical properties (eg, external quantum efficiency).

The SP value (solubility parameter/unit: ((cal/cm) ^0.5 ) in the present invention refers to a solubility parameter calculated by the so-called Fedors method described in RFFedors, Polymer Engineering Science, 14, p147 (1974). In the Fedors method, cohesive energy density and molar molecular volume are thought to depend on the type and number of substituents, and the solubility parameter is expressed by the following formula (1). The solubility parameter is unique to each compound. is a value

In Equation (1), ΣEcoh represents the cohesive energy and ΣV represents the molar molecular volume.

The SI unit of the SP value is (J/cm 3 ) ^0.5 or (MPa) ^0.5 , but (cal/cm 3 ) ^0.5 conventionally used is used in this specification. The unit of the SP value can be converted into the following formula: 1 (cal/cm 3 ) ^0.5 ≈ 2.05 (J/cm 3 ) ^0.5 ≈ 2.05 (MPa) ^0.5 .

Examples of the (meth)acrylate compound having an SP value of 10.0 or less include lauryl acrylate (SP value: 8.70), isostearyl acrylate (SP value: 8.59), isodecyl acrylate (SP value: 8.39), n-butyl acrylate (SP value: 8.82), isobornyl acrylate (SP value: 8.70), cyclohexyl acrylate (SP value: 9.26), ben Zil acrylate (SP value: 9.71), phenoxyethyl acrylate (SP value: 9.74), dicyclopentenyl acrylate (SP value: 9.71), dicyclopentenyloxyethyl acrylate (SP value: 9.65), dicyclopentanyl acrylate (SP value: 9.66), (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate (SP value: 9.21), Tetrahydrofurfuryl acrylate (SP value: 9.51), 5-ethyl-1,3-dioxan-5-yl methyl acrylate (SP value: 9.35), 2-ethylhexyl acrylate (SP value: 8.62), 2-[2-(ethoxy)ethoxy]ethyl acrylate (SP value: 9.08), methoxytriethylene glycol acrylate (SP value: 9.18), 2-ethyl Hexylcarbitol acrylate (SP value: 8.82), methoxypolyethylene glycol #400 acrylate (SP value: 9.28), methoxydipropylene glycol acrylate (SP value: 9.29), allyl methacrylate (SP value: 8.99), lauryl methacrylate (SP value: 9.02), tert-butyl methacrylate (SP value: 8.48), 2- Ethylhexyl methacrylate (SP value: 8.63), isodecyl methacrylate (SP value: 8.42), isobornyl methacrylate (SP value: 8.70), cyclohexyl methacrylate (SP value: 9.22), benzyl methacrylate (SP value: 9.64), phenoxyethyl methacrylate (SP value: 9.68), dicyclopentenyloxy Ethyl methacrylate (SP value: 9.60), dicyclopentanyl methacrylate (SP value: 9.60), 1,4-butanediol diacrylate (SP value: 9.73), 1,6-hexanediol diacrylate (SP value: 9.56), 1,9-nonanediol diacrylate (SP value: 9.39), 1,10-decanediol diacrylate (SP value: 9. 34), dipropylene glycol diacrylate (SP value: 9.60), neopentyl glycol diacrylate (SP value: 9.40), tricyclodecane dimethanol diacrylate (SP value: 9.68), triethylene glycol diacrylate (SP value: 9.77), polyethylene glycol #200 diacrylate (SP value: 9.72), polyethylene glycol #400 diacrylate (SP value: 9.58), Polyethylene glycol #600 diacrylate (SP value: 9.52), pentaerythritol triacrylate (SP value: 8.78), trimethylolpropane triacrylate (SP value: 9.88), ditrimethylolpropane tetraacrylate (SP value: 9.81), 1,4-butanediol dimethacrylate (SP value: 9.61), 1,6-hexanediol dimethacrylate (SP value) : 9.48), 1,9-nonanediol dimethacrylate (SP value: 9.33), ethylene glycol dimethacrylate (SP value: 9.78), diethylene glycol dimethacrylate (SP value: 9.71), triethylene glycol dimethacrylate (SP value: 9.66), polyethylene glycol #200 dimethacrylate (SP value: 9.63), polyethylene glycol #400 dimethacrylate (SP value: 9.53), polyethylene glycol #600 dimethacrylate (SP value: 9.49), and the like.

In the ink composition, when the curable component is composed of only a photopolymerizable compound or a photopolymerizable compound as a main component, as the photopolymerizable compound as described above, it is more preferable to use a bifunctional or higher polyfunctional photopolymerizable compound having two or more polymerizable functional groups in one molecule as an essential component in view of further increasing the durability (strength, heat resistance, etc.) of the cured product.

The content of the photopolymerizable compound contained in the ink composition is preferably 70 to 95% by mass, and more preferably 75 to 94% by mass, based on the total mass of the ink composition, from the viewpoints of easily obtaining an appropriate viscosity as an inkjet ink, improving the curability of the ink composition, improving the solvent resistance and abrasion resistance of the pixel portion (cured product of the ink composition) and obtaining better optical properties (eg, external quantum efficiency), It is more preferable that it is 80-93 mass %.

<<Photoinitiator>>

The photopolymerization initiator is preferably at least one selected from the group consisting of alkylphenone-based compounds, acylphosphine oxide-based compounds, and oxime ester-based compounds.

As an alkylphenone type photoinitiator, the compound represented by Formula (b-1) is mentioned, for example.

(Wherein, 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 each independently represent a group selected from the following formulas (R ² -1) to (R ² -7).)

As specific examples of the compound represented by the formula (b-1), compounds represented by the following formulas (b-1-1) to (b-1-6) are preferred, and compounds represented by the following formulas (b-1-1), formula (b-1-5) or formula (b-1-6) are more preferred.

As an acylphosphine oxide type photoinitiator, the compound represented by Formula (b-2) is mentioned, for example.

(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, but these groups may be substituted with an alkyl group, a hydroxyl group, a carboxyl group, a sulfone group, an aryl group, an alkoxy group, or an arylthio group.)

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

As an oxime ester type photoinitiator, the compound represented by the following formula (b-3-1) or a formula (b-3-2) is mentioned, for example.

(Wherein, 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, 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, X ¹ represents an oxygen atom or a nitrogen atom, X ² represents an oxygen atom or NR, and R represents carbon It represents an alkyl group having 1 to 6 atoms.)

As specific examples of the compound represented by the formulas (b-3-1) and (b-3-2), compounds represented by the following formulas (b-3-1-1) to (b-3-1-2) and the following formulas (b-3-2-1) to (b-3-2-2) are preferable, and compounds represented by the following formulas (b-3-1-1), formula (b-3-2-1) or formula (b-3-2-2) are more preferable.

The content of the photopolymerization initiator is preferably 0.05 to 10% by mass, more preferably 0.1 to 8% by mass, and still more preferably 1 to 6% by mass, based on the total amount of photopolymerizable compounds contained in the ink composition. In addition, a photoinitiator may be used individually by 1 type, and may mix and use 2 or more types. The ink composition containing the photopolymerization initiator in such an amount sufficiently maintains the photosensitivity during photocuring and prevents crystals of the photopolymerization initiator from precipitating when the cured film is dried, thereby suppressing deterioration of physical properties of the cured film.

When dissolving the photopolymerization initiator in the ink composition, it is preferable to use it after dissolving it in a photopolymerizable compound beforehand.

In order to dissolve in the photopolymerizable compound, it is preferable to uniformly dissolve the photopolymerizable compound by adding a photopolymerizable compound while stirring so that the reaction by heat is not initiated.

The dissolution temperature of the photopolymerization initiator may be appropriately adjusted in consideration of the solubility of the photopolymerizable compound to be used in the photopolymerizable compound and the thermal polymerization of the photopolymerizable compound, but from the viewpoint of not initiating polymerization of the photopolymerizable compound, it is preferably 10 to 50 ° C, more preferably 10 to 40 ° C, and still more preferably 10 to 30 ° C.

<<Light Scattering Particles>>

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

Examples of the material constituting the light-scattering particles include simple metals such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum, and gold; metal oxides such as silica, barium sulfate, barium carbonate, calcium carbonate, 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, and zinc oxide; metal carbonates such as magnesium carbonate, barium carbonate, bismuth carbonate, and calcium carbonate; metal hydroxides such as aluminum hydroxide; and complex oxides such as barium zirconate, calcium zirconate, calcium titanate, barium titanate and strontium titanate, and metal salts such as bismuth nitrate.

Among them, the material constituting the light-scattering particles preferably contains at least one selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate, and silica, more preferably contains at least one member selected from the group consisting of titanium oxide, barium sulfate, and calcium carbonate, and is particularly preferably titanium oxide.

When using titanium oxide, it is preferable that it is surface-treated titanium oxide from a dispersible viewpoint. Although there are well-known methods as a surface treatment method of titanium oxide, it is more preferable that the surface treatment containing at least alumina is performed.

Titanium oxide subjected to surface treatment with alumina refers to a treatment in which at least alumina is deposited on the surface of titanium oxide particles, and silica or the like can be used in addition to alumina. In addition, hydrates thereof are also contained in alumina or silica.

In this way, by subjecting the titanium oxide particles to a surface treatment containing alumina, the surfaces of the titanium oxide particles are uniformly surface coated, and when titanium oxide particles surface-treated with at least alumina are used, the dispersibility of the titanium oxide particles becomes good.

Further, when the treatment with silica and the treatment with alumina are applied to the titanium oxide particles, the treatment with alumina and silica may be performed simultaneously, in particular, the alumina treatment may be performed first, followed by the silica treatment. In addition, when processing alumina and silica respectively, it is preferable that the processing amount of alumina and silica has more silica than alumina.

Surface treatment of the titanium oxide with a metal oxide such as alumina or silica can be performed by a wet method. For example, titanium oxide particles subjected to surface treatment of alumina or silica can be produced as follows.

Titanium oxide particles (number average primary particle size: 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. Thereafter, alkali or acid is added to neutralize, and silica or alumina is deposited on the surface of the titanium oxide particles. Subsequently, filtration, washing, and drying are performed to obtain the target 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, and may be 10% by mass or less, 9% by mass or less, or 8% by mass or less based on the total mass of the ink composition.

<<Polymer Dispersant>>

The ink composition may further contain a polymer dispersant. The polymeric 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 the light scattering particles in the ink composition. The polymeric dispersing agent also contributes to the dispersion stability of the luminescent particles.

"Weight average molecular weight (Mw)" can employ a value measured using gel permeation chromatography (GPC) using polystyrene as a standard substance.

Examples of the polymer dispersant include acrylic resins, polyester resins, polyurethane resins, polyamide resins, polyether resins, phenolic resins, silicone resins, polyurea resins, amino resins, polyamine resins (polyethyleneimine, polyallylamine, etc.), epoxy resins, polyimide resins, natural rosins such as wood rosin, gum rosin, tall oil rosin, polymerized rosin, disproportionated rosin, and hydrogenated furnaces. rosin derivatives such as gin, oxidized rosin, modified rosin such as maleinized rosin, rosin amine, lime rosin, rosin alkylene oxide adduct, rosin alkyd adduct, and rosin modified phenol; and the like.

In addition, commercially available polymer dispersants include, for example, DISPERBYK (registered trademark) series by Big Chemie, TEGO (registered trademark) Dispers series by Evonik, EFKA (registered trademark) series by BASF, SOLSPERSE (registered trademark) series by Nippon Lubrizol, Ajisper (registered trademark) series by Kusumoto Kasei, DISPARLON (registered trademark) series by Kyoesha Chemical Co., Ltd. Floren series etc. can be used.

Moreover, as this polymer dispersing agent, it is especially preferable that it is a block copolymer. As an effect of applying a block copolymer to the polymer dispersing agent, the block copolymer is composed of a hydrophilic region and a pigment adsorption region, so that high dispersibility can be obtained, and better than random copolymers or crossover copolymers. Dispersibility can be obtained.

Specifically, in a random copolymer or the like, the monomers constituting the copolymer are more likely to be stably arranged in the copolymer sterically or electrically during formation of the polymer. Monomer Since the part (molecule) in which the monomer is stably arranged is sterically or electrically stable, it often becomes an obstacle when adsorbed to the surface of the pigment. On the other hand, in the block copolymer type polymer dispersant in which the molecular arrangement is controlled, the part that hinders the adsorption of the dispersant to the pigment can be disposed at a position spaced apart from the adsorbing part of the pigment and the dispersant. That is, by arranging a portion suitable for adsorption in the adsorption portion of the pigment and the dispersant and arranging a portion suitable for the adsorption portion in a portion requiring solvent affinity, particularly in the dispersion of inkjet ink containing a pigment having a small crystal size, 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. Examples of the ethylenically unsaturated monomer include the following.

styrene and styrene derivatives such as α-methylstyrene or vinyltoluene; vinyl esters of carboxylic acids such as vinyl acetate and vinyl propionate; vinyl halide; monoalkylesters of ethylenically unsaturated mono- and dicarboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid and alkanols (preferably having from 1 to 4 carbon atoms) of the aforementioned dicarboxylic acids and derivatives of the aforementioned monoalkylesters and their N-substituted derivatives, arylesters 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 their ammonium or alkali metal salts, such as vinylsulfonic acid, vinylbenzenesulfonic acid, α-acrylamidemethylpropanesulfonic acid, 2-sulfoethylene methacrylate; amides of vinylamines such as vinylformamide, vinylacetamide; unsaturated ethylenic monomers containing secondary, tertiary or quaternary amino groups or nitrogen-containing heterocyclic groups, such as vinylpyridine, vinylimidazole, aminoalkyl(meth)acrylates, aminoalkyl(meth)acrylamides, dimethylaminoethyl acrylic acid or methacrylate, di-t-butylaminoethyl acrylic acid or methacrylate, or dimethylaminomethylacrylamide or methacrylamide; zwitterionic monomers such as sulfopropyl(dimethyl)aminopropylacrylate; dienes such as butadiene, isoprene, chloroprene; (meth)acrylic acid ester; vinyl nitriles; vinylphosphonic acid and its derivatives.

A block copolymer can be synthesized using such an ethylenically unsaturated monomer according to a known method, for example, a synthesis method such as Japanese Unexamined Patent Publication No. 2005-60669 or Japanese Unexamined Patent Publication No. 2007-314617.

Among them, it is preferable to use a (meth)acrylic block copolymer, for example, Japanese Unexamined Patent Publication No. 60-89452, Japanese Unexamined Patent Publication No. 9-62002, P.Lutz, P.Masson, et al, Polym.Bull.12, 79 (1984), B.C.Anderson, G.D.Andrews, et al, Macromolecules, 14, 1601 (198 1), K.Hatada, K.Ute, et al, Polym.J.17, 977(1985), K.Hatada, K.Ute, et al, Polym.J.18, 1037(1986), Koichi Ute, Koichi Hatada, Polymer Processing, 36, 366(1987), Toshinobu Higashimura, Mitsuo Sawamoto, Journal of Polymers, 4 6, 189 (1989), M. Kuroki, T. Aida, J. Am. Chem. Sic, 109, 4737 (1987), Takuzo Aida, Shohei Inoue, Organic Synthetic Chemistry, 43,300 (1985), D. Y. Sogoh, W.R. Hertler, et al, Macromolecules, 20, 1473 (1987) , K.Matyaszewski, et al, Chem.Rev.2001, 101, 2921-2990, etc., can be synthesized by referring to known methods.

The polymeric dispersant used in the present invention has a basic polar group, and examples of the basic functional group include primary, secondary and tertiary amino groups, ammonium groups, imino groups, and nitrogen-containing heterocyclic groups such as pyridine, pyrimidine, pyrazine, imidazole and triazole. The amine value of the polymer dispersant is preferably 6 to 90 mgKOH/g, more preferably 7 to 70 mgKOH/g, still more preferably 8 to 50 mgKOH/g. When the amine value of the polymer dispersant is less than 6 mgKOH/g, the adsorption of the polymer dispersant to the light diffusing particles is low, and when the amine value is greater than 90 mgKOH/g, the polarity is high, which tends to cause aggregation and deterioration in storage stability, and the dispersibility of the light-emitting particles is also deteriorated due to this influence.

The amine value of the polymer dispersing agent can be measured as follows. Prepare a sample solution in which polymer dispersant xg and 1 mL of bromophenol blue TS are dissolved in 50 mL of a mixed solution of toluene and ethanol mixed at a volume ratio of 1: 1, and titrate with 0.5 mol/L hydrochloric acid until the sample solution turns green. The amine value can be calculated by the following formula.

Amin value = y/x × 28.05

In the formula, y represents the titration amount (mL) of 0.5 mol/L hydrochloric acid required for titration, and x represents the mass (g) of the polymer dispersant.

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

The ink composition may contain other components other than luminescent particles, photopolymerizable compounds, photopolymerization initiators, light scattering particles, and polymer dispersants within a range that does not impair the effects of the present invention. Examples of these other components include polymerization inhibitors, antioxidants, leveling agents, chain transfer agents, dispersing aids, thermoplastic resins, and sensitizers.

<<Polymerization Inhibitor>>

Examples of the polymerization inhibitor include p-methoxyphenol, cresol, t-butylcatechol, 3,5-di-t-butyl-4-hydroxytoluene, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), and 4-methoxy-1-naph. phenolic compounds such as tol, 4,4'-dialkoxy-2,2'-bi-1-naphthol; Quinones such as hydroquinone, methylhydroquinone, tert-butylhydroquinone, p-benzoquinone, methyl-p-benzoquinone, tert-butyl-p-benzoquinone, 2,5-diphenylbenzoquinone, 2-hydroxy-1,4-naphthoquinone, 1,4-naphthoquinone, 2,3-dichloro-1,4-naphthoquinone, anthraquinone, and diphenoquinone compound; p-phenylenediamine, 4-aminodiphenylamine, N,N'-diphenyl-p-phenylenediamine, N-i-propyl-N'-phenyl-p-phenylenediamine, N-(1.3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, diphenylamine, N-phenyl-β-naphthylamine, 4,4'-dicumyl-diphenylamine, amine compounds such as 4,4'-dioctyl-diphenylamine; thioether compounds such as phenothiazine and distearylthiodipropionate; N-oxyl compounds such as 2,2,6,6-tetramethylpiperidine-1-oxyl free radical, 2,2,6,6-tetramethylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical; N-nitrosodiphenylamine, N-nitrosophenylnaphthylamine, N-nitrosodinapthylamine, p-nitrosophenol, nitrosobenzene, p-nitrosodiphenylamine, α-nitroso-β-naphthol, N,N-dimethyl-p-nitrosoaniline, p-nitrosodiphenylamine, p-nitrondimethylamine, p-nitron-N,N-diethylamine, N-nitrosoethanolamine , N-nitroso-di-n-butylamine, N-nitroso-N-n-butyl-4-butanolamine, N-nitroso-diisopropanolamine, N-nitroso-N-ethyl-4-butanolamine, 5-nitroso-8-hydroxyquinoline, N-nitrosomorpholine, N-nitroso-N-phenylhydroxylamine ammonium salt (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., "Q-1300"), nitrosobenzene, 2,4,6-tri-tert-butylnitronbenzene, N-nitroso-N-methyl-p-toluenesulfonamide, N-nitroso-N-ethylurethane, N-nitroso-N-n-propylurethane, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 1-nitroso-2-naphthol-3,6-sul and nitroso-based compounds such as sodium phonate, sodium 2-nitroso-1-naphthol-4-sulfonate, 2-nitroso-5-methylaminophenol hydrochloride, 2-nitroso-5-methylaminophenol hydrochloride, and Q-1301 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

It is preferable that it is 0.01-1.0 mass % with respect to the total amount of photopolymerizable compounds contained in an ink composition, and, as for the addition amount of a polymerization inhibitor, it is more preferable that it is 0.02-0.5 mass %.

<<Antioxidants>>

As an antioxidant, for example, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (product name "IRGANOX (registered trademark) 1010"), thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (product name "IRGANOX (registered trademark) 1035"), octadecyl-3-(3 5-di-tert-butyl-4-hydroxyphenyl)propionate (product name "IRGANOX (registered trademark) 1076"), isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (product name "IRGANOX (registered trademark) 1135"), 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)methyl Ren (product name "IRGANOX1330"), 4,6-bis(octylthiomethyl)-o-cresol (product name "IRGANOX (registered trademark) 1520L"), 2,4-bis[(dodecylthio)methyl]-6-methylphenol (product name "IRGANOX (registered trademark) 1726"), bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propion acid] [ethylenebis(oxyethylene)] (product name "IRGANOX (registered trademark) 245"), 1,6-hexanediolbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (product name "IRGANOX (registered trademark) 259"), tris (3,5-dit-butyl-4-hydroxybenzyl) isocyanate (product name "IRGANOX (registered trademark) 3114 "), 1,3,5-tris[[4-(1,1-dimethylethyl)-3-hydroxy-2,6-dimethylphenyl]methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (product name "IRGANOX (registered trademark) 3790"), bis[4-(1,1,3,3-tetramethylbutyl)phenyl]amine (product name "IRGANOX (registered trademark)) ) 5057”), 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol (product name “IRGANOX (registered trademark) 565”) (above, manufactured by BASF Corporation); Tris(3,5-dit-butyl-4-hydroxybenzyl) isocyanate (product name “Adecas Tab (registered trademark) AO-20”), 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (product name “Adecas Tab (registered trademark) AO-30"), 4,4'-butylidenebis(3-methyl-6-tert-butyl)phenol (product name "Adeka Staff (registered trademark) AO-40"), n-ocradecyl-3 (3',5'-di-t-butyl-4'-hydroxyphenyl) propionate (product name "Adeka Staff (registered trademark) AO-50"), product name "Adeka Staff (registered trademark) AO-40") AO-60", 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (product name "Adecastab (registered trademark) AO-80"), trisphosphite (4-nonylphenyl) (product name "Adecastab (registered trademark)) 1178”), trisphosphite (2,4-di-tert-butylphenyl (product name “Adeka Staff (registered trademark) 2112”), 2,4,8,10-tetrakis(1,1-dimethylethyl)-6-[(2-ethylhexyl)oxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphosine (product name “Adeka Staff (registered trademark) HP-10) ", 3,9-bis (octadecyloxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane (product name "Adecastab (registered trademark) PEP-8"), 3,9-bis (2,4-di-tert-butylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane ( Product name "Adeka Staff (registered trademark) PEP-24", 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (product name "Adeka Staff (registered trademark) PEP-36", triphenylphosphite (product name "Adeka Staff (registered trademark) TPP"), tetraalkyl (C12-15)-4,4'-isopropylidenediphenyldiphosphite (product name "Adeka Step (registered trademark) 1500") (above, manufactured by ADEKA Co., Ltd.); trisnonylphenyl phosphite (product name "JP-351"), tricresyl phosphite (product name "JP-3CP"), triethyl phosphite (product name "JP-302"), tris (2-ethylhexyl phosphite (product name: "JP-308E"), tridecyl phosphite (product name: "JP-310"), trilauryl phosphite (product name: "JP-312L"), tris (tridecyl) phosphite (product name: "JP-333"), trioleyl phosphite (product name: "JP-318-O"), diphenyl mono(2-ethylhexyl) phosphite (product name) "JPM-308"), diphenyl monodecyl phosphite (product name "JPM-311"), diphenyl mono(tridecyl)phosphite (product name "JPM-313"), bis(decyl)pentaerythritol diphosphite (product name "JPE-10"), tristearyl phosphite (product name "JP-318E") (above, Johoku Chemical Industry Co., Ltd.) first); Butylhydroxytoluene ("product name "Sumilizer (registered trademark) BHT"), 4,4'-butylidenebis(3-methyl-6-t-butylphenol) (product name "Sumilizer (registered trademark) BBM-S"), 3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxa Spiro[5,5]undecane (product name "Sumilizer (registered trademark) GA-80") (above, manufactured by Sumitomo Chemical Co., Ltd.), tetrakis (2,4-di-t-butylphenyl-4,4'-biphenylenediphosphonite) (product name "Hostanox (registered trademark) P-EPQ") (above, Clariant Chemicals Co., Ltd.), tetrakis (2, 4-di-tert-butyl-5-methylphenyl)-4,4'-biphenylenediphosphonite" (product name "GSY-P100") (above, manufactured by Sakai Chemical Industry Co., Ltd.); and the like.

It is preferable that it is 0.01-2.0 mass % with respect to the total amount of photopolymerizable compounds contained in an ink composition, and, as for the addition amount of antioxidant, it is more preferable that it is 0.02-1.0 mass %.

<<Leveling agent>>

Although there is no limitation in particular as a leveling agent, when forming a thin film of luminescent particle|grains, the compound which can reduce film thickness nonuniformity is preferable.

Examples of such leveling agents include alkyl carboxylates, alkyl phosphates, alkylsulfonates, fluoroalkylcarboxylates, fluoroalkylphosphates, fluoroalkylsulfonates, polyoxyethylene derivatives, fluoroalkylethylene oxide derivatives, polyethylene glycol derivatives, alkylammonium salts, and fluoroalkylammonium salts.

It is preferable that it is 0.005-2 mass % with respect to the total amount of photopolymerizable compounds contained in an ink composition, and, as for the addition amount of a leveling agent, it is more preferable that it is 0.01-0.5 mass %.

<<Chain Transfer Agents>>

A chain transfer agent is a component used for the purpose of further improving the adhesion of the ink composition to the substrate.

As a chain transfer agent, aromatic hydrocarbons, halogenated hydrocarbons, a mercaptan compound, a thiol compound, a sulfide compound etc. are mentioned, for example.

It is preferable that it is 0.1-10 mass % with respect to the total amount of photopolymerizable compounds contained in an ink composition, and, as for the addition amount of a chain transfer agent, it is more preferable that it is 1.0-5 mass %.

<<thermoplastic resin>>

Examples of the thermoplastic resin include urethane-based resins, acrylic-based resins, polyamide-based resins, polyimide-based resins, styrene maleic acid-based resins, styrene maleic anhydride-based resins, and polyester acrylate-based resins.

<<sensitizer>>

As the sensitizer, thioxanthone-based compounds, benzophenone-based compounds, quinone-based compounds, amines, and the like can be used. Examples of such a sensitizer include 2-isopropylthioxanthone, 2,4-diethylthioxanthone, benzophenone, 4,4'-bis(diethylamino)benzophenone, 2-ethylanthraquinone, trimethylamine, methyldimethylamine, triethanolamine, p-diethylaminoacetophenone, p-dimethylaminobenzoate ethyl, p-dimethylaminobenzoate isoamyl, N,N-dimethylbenzylamine etc. can be mentioned.

<<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, and still more preferably in the range of 7 to 12 mPa s, from the viewpoint of ejection stability during inkjet printing. In this case, since the meniscus shape of the ink composition in the ink ejection hole of the ejection head is stabilized, ejection control of the ink composition (for example, control of ejection amount and ejection timing) becomes easy. Also, the ink composition can be smoothly discharged from the ink discharge hole. In addition, the viscosity of an ink composition can be measured with an E-type viscometer, for example.

The viscosity increase rate of the ink composition may be 5% or less, 1% or less, 0.5% or less, or 0.01% or more. The viscosity increase rate of an ink composition is a value computed by the following formula.

Expression: (η ₁ -η ₀ )/η ₀ ×100

Here, η ₁ represents the viscosity of the ink composition measured at 30 ° C after storage at 40 ° C for one week, and η ₀ represents the viscosity 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 inkjet printing. It is preferable that it is the range of 20-40 mN/m, and, as for the specific value of surface tension, it is more preferable that it is the range of 25-35 mN/m. By setting the surface tension within the above range, it is possible to suppress the occurrence of flight curves of droplets of the ink composition. In addition, a flight curve means that the landing position of an ink composition shifts by 30 micrometers or more with respect to a target position when ejecting an ink composition from an ink ejection hole.

The above ink composition can be prepared, for example, by dispersing luminescent particles in a solution in which a NOR-type hindered amine compound and, if necessary, a photopolymerizable compound and a photopolymerization initiator are mixed. Dispersion of the luminescent particles can be performed by using a disperser such as a ball mill, sand mill, bead mill, three roll mill, paint conditioner, attritor, dispersion stirrer, or ultrasonic wave, for example.

<Ink composition set>

Another embodiment of the present invention is an ink composition set. An ink composition set of one embodiment includes the ink composition of the above-described embodiment. The ink composition set may include, in addition to the ink composition (luminescent ink composition) of the above-described embodiment, an ink composition (non-luminescent ink composition) containing no luminescent particles. The non-luminescent ink composition is, for example, a curable ink composition. The non-luminescent ink composition may be a conventionally known ink composition, or may have the same composition as the ink composition (luminescent ink composition) of the above-described embodiment except that it does not contain luminescent particles.

Since the non-luminescent ink composition does not contain luminescent particles, when light is incident on a pixel portion formed of the non-luminescent ink composition (a pixel portion including a 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-luminescent ink composition is suitably used to form a pixel portion of the same color as the light from the light source. For example, when the light from the light source is light (blue light) having a wavelength in the range of 420 to 480 nm, the pixel portion formed by the non-luminescent ink composition may be a blue pixel portion.

The non-luminescent ink composition preferably contains light-scattering particles. When the non-luminescent ink composition contains light-scattering particles, according to the pixel portion formed of the non-luminescent ink composition, the light incident on the pixel portion can be scattered, thereby reducing the light intensity difference between the light emitted from the pixel portion and the viewing angle.

<Light conversion layer and color filter>

Another embodiment of the present invention is a light conversion layer and a color filter. Hereinafter, the detail of the light conversion layer and color filter obtained using the ink composition or ink composition set of the above-mentioned embodiment is demonstrated, referring drawings. However, the following embodiments are embodiments in the case where the ink composition contains light scattering particles. In addition, in the following description, the same code|symbol is used for the same or equivalent element, and overlapping description is abbreviate|omitted.

1 is a schematic cross-sectional view of a color filter according to an embodiment. As shown in FIG. 1 , the color filter 100 includes a substrate 40 and a light conversion layer 30 provided on the substrate 40 . The light conversion layer 30 includes a plurality of pixel portions 10 and a light blocking portion 20 .

The light conversion layer 30 includes a first pixel portion 10a, a second pixel portion 10b, and a third pixel portion 10c as the pixel portion 10. The first pixel section 10a, the second pixel section 10b, and the third pixel section 10c are arranged in a grid pattern so that this order is repeated. The light blocking portion 20 is provided 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 between the third pixel portion 10c and the first pixel portion 10a. In other words, these adjacent pixel parts are separated from each other by the light-shielding part 20 .

The first pixel portion 10a and the second pixel portion 10b are light-emitting pixel portions (light-emitting pixel portions) each containing a cured product of the ink composition of the above-described embodiment. 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, and first luminescent particles 11a and first light scattering particles 12a respectively dispersed in the first curing component 13a. Similarly, the second pixel portion 10b includes a second curing component 13b, and second luminescent particles 11b and second light scattering particles 12b respectively dispersed in the second curing component 13b. The curing component is a component obtained by polymerization of a photopolymerizable compound, and includes a polymer of the photopolymerizable compound. In addition to the above polymer, the curing component may contain components 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 the first light-scattering particles 12a and the second light-scattering particles 12b may be the same or different.

The first luminescent particles 11a are red luminescent nanocrystal particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light having a peak emission wavelength in the range of 605 to 665 nm. That is, the first pixel portion 10a may be referred to as a red pixel portion for converting blue light into red light. Further, the second luminescent particles 11b are green luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having a peak emission wavelength in the range of 500 to 560 nm. That is, the second pixel portion 10b may be referred to 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 1% by mass or more, 2% by mass or more, or 3% by mass or more, based on the total mass of the cured product of the luminescent ink composition, from the viewpoint of further improving the external quantum efficiency and obtaining excellent luminous intensity. The content of the luminescent particles is preferably 15% by mass or less, 10% by mass or less, or 7% 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 luminous intensity.

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

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

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

The content of the light-scattering particles in the non-luminescent pixel portion may be 1 mass% or more, 5 mass% or more, or 10 mass% or more based on the total mass of the cured product of the non-luminescent ink composition from the viewpoint of further reducing the light intensity difference in the viewing angle. The content of the light-scattering particles may be 80% by mass or less, 75% by mass or less, or 70% by mass or less based on the total mass of the cured product of the non-luminescent ink composition from the viewpoint of further reducing light reflection.

The thickness of the pixel portions (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. The thickness of the pixel portions (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.

The light blocking unit 20 is a so-called black matrix provided for the purpose of preventing color mixing by separating adjacent pixel units and preventing leakage of light from a light source. The material constituting the light-shielding portion 20 is not particularly limited, and a cured product of a resin composition in which light-blocking particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments are incorporated in a binder polymer in addition to metals such as chromium can be used. As the binder polymer used herein, one or a mixture of two or more resins such as polyimide resin, acrylic resin, epoxy resin, polyacrylamide, polyvinyl alcohol, gelatin, casein, and cellulose, a photosensitive resin, an O/W emulsion type resin composition (e.g., one obtained by emulsifying a reactive silicone), and the like can be used. The thickness of the light-shielding portion 20 may be, for example, 0.5 μm or more and 10 μm or less.

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

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

The color filter 100 can be manufactured by, for example, forming the light blocking portion 20 in a pattern on the substrate 40, and then forming the pixel portion 10 in the pixel portion formation region partitioned by the light blocking portion 20 on the substrate 40. The pixel portion 10 can be formed by a method including a step of selectively attaching an ink composition (inkjet ink) to the pixel portion formation region on the substrate 40 by an inkjet method, and a step of irradiating the ink composition with active energy rays (eg, ultraviolet rays) and curing the ink composition to obtain a light-emitting pixel portion. A luminescent pixel portion is obtained by using the above-described luminescent ink composition as the ink composition, and a non-luminescent pixel portion is obtained by using a non-luminescent ink composition.

The method of forming the light-shielding portion 20 includes a method of forming a thin film of a metal 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 side of the substrate 40, and patterning the thin film. The metal thin film can be formed by, for example, sputtering or vacuum deposition, and the thin film of a resin composition containing light-shielding particles can be formed by, for example, coating or printing. A photolithography method etc. are mentioned as a method of patterning.

Examples of the inkjet method include a bubble jet (registered trademark) method using an electrothermal converter as an energy generating element, a piezojet method using a piezoelectric element, and the like.

Curing of the ink composition can be performed using, for example, a mercury lamp, a metal halide lamp, a xenon lamp, an LED or the like. LEDs are preferable from the viewpoints of reduction in thermal load to the coating film and low power consumption.

It is preferable that it is 250 nm - 440 nm, and, as for the wavelength of the light to irradiate, it is more preferable that it is 300 nm - 400 nm. When using LED, it is preferable that it is 350-400 nm or less from a viewpoint of sufficiently hardening a film thickness of 10 micrometers or more, for example. Moreover, it is preferable that it is 0.2-2 kW/cm<2>, and, as for the intensity of light, it is more preferable that it is 0.4-1 kW/cm<2>. At a light intensity of less than 0.2 kW/cm, the coating film cannot be sufficiently cured, and at a light intensity of 2 kW/cm or more, unevenness occurs in the curing degree of the surface of the coating film and the inside, and the smoothness of the coating film surface is poor. This is not preferable. It is preferable that it is 10 mJ/cm<2> or more, and, as for the irradiation amount (exposure amount) of light, it is more preferable that it is 4000 mJ/cm<2> or less.

Although the curing of the coating film can be performed in air or in an inert gas, it is more preferable to perform curing in an inert gas in order to suppress oxygen inhibition on the surface of the coating film and oxidation of the coating film. As an inert gas, nitrogen, argon, carbon dioxide, etc. are mentioned. By curing the coating film under these conditions, the external quantum efficiency of the resulting light conversion layer can be further improved since the coating film can be completely cured.

For example, the light conversion layer may include, instead of or in addition to the third pixel portion 10c, a pixel portion (blue pixel portion) containing a cured product of a luminescent ink composition containing blue luminescent nanocrystal particles. Further, the light conversion layer may include a pixel portion (for example, a yellow pixel portion) made of a cured product of a luminescent ink composition containing nanocrystal particles emitting light of a color other than red, green, and blue. In these cases, each of the luminescent particles contained in each pixel portion of the light conversion layer preferably has an absorption maximum wavelength in the same wavelength region.

Moreover, at least a part of the pixel part of a light conversion layer may contain the hardened|cured material of the composition containing pigments other than luminescent particle|grains.

Moreover, the color filter may be equipped with the ink repellent layer containing the material which has ink repellency narrower than a width|variety than a light-shielding part on the pattern of a light-shielding part. Alternatively, instead of providing an ink repellent layer, a photocatalyst-containing layer as a wettability-variable layer may be formed in a solid application form in a region including a pixel portion formation region, and then the photocatalyst-containing layer may be exposed by irradiating light through a photomask to selectively increase the ink affinity of the pixel portion formation region. As a photocatalyst, titanium oxide, zinc oxide, etc. are mentioned.

Further, the color filter may include an ink receiving layer made of hydroxypropyl cellulose, polyvinyl alcohol, gelatin or the like between the substrate and the pixel portion.

Further, the color filter may include a protective layer on the pixel portion. This protective layer is provided to flatten the color filter and prevent elution of components contained in the pixel portion or components contained in the pixel portion and components contained in the photocatalyst-containing layer to the liquid crystal layer. As the material constituting the protective layer, those used as known protective layers for color filters can be used.

In addition to the light emitting particles described above, the pixel portion of the light conversion layer of the present embodiment may further contain a pigment substantially the same color as the light emitting color of the light emitting particles. In order to contain a pigment in the pixel portion, the ink composition may contain a pigment.

In addition, among the red pixel portion R, the green pixel portion G, and the blue pixel portion B in the light conversion layer of the present embodiment, one or two light emitting pixel portions may be a pixel portion containing a color material without containing luminescent particles. As the color material that can be used here, known color materials can be used, and examples of the color material used for the red pixel portion R include diketopyrrolopyrrole pigments and/or anionic red organic dyes. As a color material used for the green pixel portion G, at least one selected from the group consisting of a halogenated copper phthalocyanine pigment, a phthalocyanine-based green dye, a phthalocyanine-based blue dye, and a mixture of azo-based yellow organic dyes is exemplified. As a color material used for the blue pixel part (B), an epsilon-type copper phthalocyanine pigment and/or a cationic blue organic dye are mentioned. The amount of these colorants used in the light conversion layer is preferably 1 to 5% by 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.

Example

Hereinafter, the present invention will be specifically described by examples. However, the present invention is not limited only to the following examples.

As the hindered amine compound (A), the following compounds were prepared.

(A-1) Flamestab NOR116FF (NOR type, melting point 108 to 123 ° C, molecular weight 2261)

(A-2) TINUVIN (registered trademark) NOR371 (NOR type, melting point 91 to 104 ° C., molecular weight 2800 to 4000)

(A-3) TINUVIN (registered trademark) 123 (NOR type, melting point <20 ° C (liquid phase), molecular weight 737)

(A-4) TINUVIN (registered trademark) 144 (NR type, melting point 147 to 149°C, molecular weight 685)

(A-5) Adecastab (registered trademark) LA-72 (NR type, melting point <20 ° C. (liquid phase), molecular weight 509)

Note that (A-4) and (A-5) are not NOR-type hindered amine compounds, but NR-type hindered amine compounds, and have a structure in which a methyl group is bonded to a nitrogen atom.

As the polymer dispersant (B), (B-1) EFKA (registered trademark) PX-4701 was prepared.

As antioxidants (C), (C-1) IRGANOX (registered trademark) 1010 (phenolic) and (C-2) Hostanox (registered trademark) P-EPQ (phosphorus) were prepared.

As the photopolymerizable compound (D), a compound shown below was prepared.

(D-1) isobornyl methacrylate (light ester IB-X, monofunctional, cyclic, viscosity: 6 mPa·s/25°C)

(D-2) lauryl methacrylate (light ester L, monofunctional, chain, viscosity: 3-8 mPa s/25°C)

(D-3) Phenoxyethyl methacrylate (light ester PO, monofunctional, cyclic, viscosity: 7 mPa·s/25°C)

(D-4) 1,6-hexanediol dimethacrylate (light ester 1,6-HX, bifunctional, chain, viscosity: 5-6 mPa s/25°C)

(D-1) - (D-4) are all made by Kyoeisha Chemical Co., Ltd.

As a photopolymerization initiator (E), a compound shown below was prepared.

(E-1) Omnirad TPO-H (TPO-H)

(E-2) Omnirad 819 (O-819)

(E-1) and (E-2) are both made by IGM RESINS.

As light-scattering particles (F), (F-1) titanium oxide (CR60-2) was prepared.

<Adjustment of luminescent particle (X) dispersion>

(Adjustment of luminescent particle dispersion)

First, 0.81 g of cesium carbonate, 40 mL of 1-octadecene, and 2.5 mL of oleic acid were mixed to obtain a liquid mixture. Next, after drying this liquid mixture under reduced pressure at 120°C for 10 minutes, it was heated at 150°C in an argon atmosphere. In this way, a cesium-oleic acid solution was obtained.

Meanwhile, 138.0 mg of lead (II) bromide and 10 mL of 1-octadecene were mixed to obtain a mixed solution. Next, after drying this mixed solution under reduced pressure at 120°C for 10 minutes, 1 mL of 3-aminopropyltriethoxysilane was added to the mixed solution under an argon atmosphere. Thereafter, a 1.3 mL cesium-oleic acid solution was added to the liquid mixture at 140°C, and the mixture was reacted by heating and stirring for 5 seconds, followed by cooling in an ice bath.

Subsequently, after stirring the reaction solution under air (23°C, 45% humidity) for 60 minutes, 20 mL of ethanol was added.

The obtained suspension was centrifuged (3,000 rotations/minute, 5 minutes), solid matter was collected, and luminescent particles X-1 were obtained.

This luminescent particle X-1 is a perovskite-type lead cesium tribromide crystal provided with a surface layer, and the average particle diameter was 10 nm by transmission electron microscope observation. In addition, the surface layer was a layer composed of 3-aminopropyltriethoxysilane, and the thickness thereof was 1 nm. That is, the luminescent particle X-1 was a particle coated with silica.

Furthermore, the luminescent particle dispersion 1 in which the luminescent particle X-1 was disperse|distributed was obtained by dispersing the luminescent particle X-1 in isobornyl methacrylate so that the solid content concentration might become 2.9 mass %.

<Preparation of luminescent particle dispersion>

A luminescent particle dispersion was obtained by mixing the luminescent particles and the photopolymerizable compound so as to have the composition shown in Table 1 and stirring in a rotary evaporator.

<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.), 1.0 parts by mass of polymer dispersant “EFKA PX4701” (amine value: 40.0 mgKOH/g, manufactured by BASF Japan Co., Ltd.), and phenoxyethyl methacrylate (Light Ester PO; Kyoesha Chemical Co., Ltd.) Shaze) 14.0 parts by mass were mixed. Further, zirconia beads (diameter: 1.25 mm) were added to the obtained formulation, and the container was capped and shaken for 2 hours using a paint conditioner to disperse the formulation, thereby obtaining a light diffusing particle dispersion 1. The average particle diameter of the light diffusing particles after the dispersion treatment was measured using NANOTRAC WAVE II and found to be 0.245 μm.

<Preparation of Ink Composition>

(Adjustment of Ink Composition (1))

As the ink composition of Example 1, 5.15 parts by mass of luminescent particle dispersion 1 (2.9 mass% of luminescent particle concentration), 0.75 parts by mass of light-scattering particle dispersion 1 (titanium oxide content: 40.0 mass%), 1.60 parts by mass of "lauryl methacrylate" (product name: Light Ester LM, manufactured by Kyoeisha Chemical Co., Ltd.) as a photopolymerizable compound, 2.0 parts by mass of "1,6-hexanediol dimethacrylate" (product name: Light Ester 1,6-HX, manufactured by Kyoeisha Chemical Co., Ltd.), and 0.3 parts by mass of "diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide" (product name: Omnirad TPO-H, manufactured by BASF Japan Co., Ltd.) and "bis(2,4,6, -trimethylbenzoyl) phenylphosphine oxide” (product name: Omnirad 819, manufactured by BASF Japan Co., Ltd.) 0.15 parts by mass, and “pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]” (product name: Irganox (registered trademark) 1010, manufactured by BASF Japan Co., Ltd.) 0 as an antioxidant 05 parts by mass and 0.05 parts by mass of "tetrakis(2,4-di-tert-butylphenyl)-1,1-biphenyl-4,4'-diylbisphosphonite" (product name: Hostanox (registered trademark) P-EPQ, manufactured by Clariant Chemicals Co., Ltd.) were mixed and uniformly dissolved in a container filled with argon gas. . Furthermore, argon gas was introduced into the container containing the obtained filtrate, and the inside of the container was saturated with argon gas. Subsequently, the ink composition (1) was obtained by reducing the pressure and removing the argon gas. The content of the luminescent particles is 1.5% by mass, the content of IB-X is 50.0% by mass, the content of LM is 16.0% by mass, the content of PO is 4.2% by mass, the content of 1,6-HX is 20.0% by mass, the content of TPO-H is 3.0% by mass, the content of O-819 is 1.5% by mass, Ir The content of ganox 1010 was 0.5% by mass, the content of P-EPQ was 0.5% by mass, the content of light scattering particles was 3.0% by mass, and the content of the polymer dispersant was 0.3% by mass. In addition, the said content is a content based on the total mass of an ink composition.

(Adjustment of Ink Compositions (2) to (9) and (C1) to (C3))

The ink compositions (2) to (9) of Examples 2 to 9 and the ink compositions of Comparative Examples 1 to 3 (C 1) to (C3) were obtained.

<Production of light conversion layer (sample for evaluation)>

The obtained ink composition was applied onto a glass substrate ("EagleXG", manufactured by Corning) by 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 at an exposure amount of 10 J/cm 2 in a nitrogen atmosphere. In this way, the ink composition was cured to form a layer containing a cured product of the ink composition on the glass substrate, and this was used as a light conversion layer.

<Evaluation of Ink Composition and Light Conversion Layer>

(Example 1)

<Viscosity of Ink Composition>

The viscosity (initial viscosity) of the ink composition at 30°C was measured using an E-type viscometer.

<Coating film curability>

When the surface of the obtained light conversion layer 1 was evaluated according to the following criteria by palpation using a cotton swab, the surface was not damaged and there was no tack feeling.

〔Evaluation standard〕

◎: There is no scratch on the surface of the light conversion layer 1, and there is no tackiness.

○: The surface of the light conversion layer 1 is not scratched, and although there is a slight tacky feeling, it is a level that is not problematic in practical use.

△: The surface of the light conversion layer 1 is slightly scratched and has a tacky feeling.

×: The surface of the light conversion layer 1 is scratched, and a part of the cured film adheres to the cotton swab.

<Bleed test>

After the obtained light conversion layer 1 was allowed to stand at 60 ° C. for 30 days, it was further allowed to stand at 25 ° C. for 1 day. After that, the surface of the light conversion layer 1 was visually observed, and the presence or absence of bleed (components eluted from the light conversion layer 1 were exuded to the surface) and the presence or absence of whitening (whether or not the surface of the light conversion layer 1 was whitened due to the elution component) was confirmed.

○: No bleed, no whitening.

Δ: There is bleeding, but there is no whitening.

x: There is bleed and there is also whitening.

<Evaluation of light fastness under high temperature>

(Light fastness test under high temperature: evaluation of external quantum efficiency (EQE))

An integrating sphere was placed above a blue LED (peak emission wavelength: 450 nm) manufactured by CCS Co., Ltd. as a surface emitting light source, and an emission spectrophotometer manufactured by Otsuka Denshi Co., Ltd. (trade name "MCPD-9800") was connected to the integrating sphere. Next, the evaluation sample 1 described above was inserted between the blue LED and the integrating sphere, the blue LED was turned on, and the observed spectrum and illuminance at each wavelength were measured with a radiation spectrophotometer. From the obtained spectrum and illuminance, the external quantum efficiency (EQE) was determined as follows.

The external quantum efficiency is a value indicating what proportion of light (photon) incident on the light conversion layer is emitted to the observer side as fluorescence. Therefore, when this value is large, it indicates that the light conversion layer has excellent light emitting properties, and is an important evaluation index. The external quantum efficiency (EQE) is calculated by the following formula (a).

EQE[%]=P2/E(Blue)×100... (a)

In the formula, E (Blue) represents the total value of "illuminance × wavelength ÷ hc" in the wavelength range of 380 to 490 nm, and P2 represents the total value of "illuminance × wavelength ÷ hc" in the wavelength range of 500 to 650 nm. These are values corresponding to the number of observed photons. Also, h is the Planck constant, and c is the speed of light.

Here, EQE means that the higher the numerical value, the smaller the deterioration of the semiconductor nanocrystal by ultraviolet rays in the curing process of the coating film, that is, the better the stability against ultraviolet rays. For use as a light conversion layer, EQE is preferably 20% or more, more preferably 25% or more, and means excellent.

The EQE measured immediately after producing the light conversion layer was referred to as the initial external quantum efficiency EQE ₀ , and when EQE ₀ was measured, it was 32%.

(Evaluation of external quantum efficiency retention rate)

Thereafter, the produced light conversion layer was irradiated with LED light at 50°C for 2 weeks. The external quantum efficiency after irradiation was set to EQE _h , and the external quantum retention rate [%] of the light conversion layer was calculated by the following formula (b), and it was 81%.

External quantum retention [%] = EQE _h /EQE ₀ × 100 . (b)

The light conversion layer preferably has a higher EQE _h in addition to EQE ₀ . A light conversion layer means that the light resistance under high temperature is excellent, so that the external quantum efficiency retention rate is high.

As shown in Table 1, the ink compositions of Examples 1 to 9 containing a NOR-type hindered amine compound are suitable as ink-jet ink compositions in that they have the above-described ink viscosities and excellent curability. Since the cured products of the ink compositions of Examples 1 to 9 are excellent in light resistance at high temperatures, the ink compositions are suitable for use as a light conversion layer. The ink compositions of Examples 1 to 4 and 7 to 8 containing a NOR-type hindered amine compound having a melting point of more than 90°C do not cause bleeding or whitening on the surface of the light conversion layer 1, and are particularly preferable.

On the other hand, all of the ink compositions of Comparative Example 1 containing no hindered amine compound and Comparative Examples 2 to 3 containing an NR-type hindered amine compound had insufficient light resistance under high temperatures.

10: pixel part
10a: first pixel unit
10b: second pixel unit
10c: third pixel unit
11a: first luminescent particles
11b: second luminescent particles
12a: first light scattering particles
12b: second light scattering particles
12c: third light scattering particles
20: light blocking part
30: light conversion layer
40: base
100: color filter

Claims (12)

A NOR-type hindered amine compound having a structure represented by the following formula (1a) or (1b), a melting point of 70° C. or higher and a mass average molecular weight of 1000 or higher;
The luminescent particle is a particle having a surface layer on the surface of the semiconductor nanocrystal particle, and the surface layer contains a polymer of a silane compound having an amino group and a hydrolyzable silyl group on the surface of the semiconductor nanocrystal particle, and oleic acid. An ink composition for inkjet.

[In Formula (1a), n represents an integer of 1 to 15.]

[In formula (1b), R is the following formula (1b-R):

represents the group represented by In formula (1b-R), * represents a bonding site with a nitrogen atom.] The ink composition for inkjet according to claim 1, wherein the photopolymerizable compound has an SP value of 10.0 or less. The ink composition for inkjet according to claim 1 or 2, wherein the photopolymerizable compound has a cyclic structure. The ink composition for inkjet according to claim 1 or 2, further comprising light-scattering particles. The ink composition for inkjet according to claim 1 or 2, further comprising a polymeric dispersant. The ink composition for inkjet according to claim 1 or 2, which has a viscosity of 7 to 12 mPa·s at 30°C. A plurality of pixel units and a light shielding unit provided between the plurality of pixel units,
The light conversion layer in which the said plurality of pixel parts has a light-emitting pixel part containing the hardened|cured material of the ink composition for inkjets of Claim 1 or 2. A color filter comprising the light conversion layer according to claim 7 . delete delete delete delete

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