WO2022181430A1

WO2022181430A1 - Color filter inkjet ink composition, cured material, phototransformation layer, and color filter

Info

Publication number: WO2022181430A1
Application number: PCT/JP2022/006292
Authority: WO
Inventors: 麻里子利光; 栄志乙木; 崇之三木
Original assignee: Dic株式会社
Priority date: 2021-02-26
Filing date: 2022-02-17
Publication date: 2022-09-01
Also published as: JP2024049408A

Abstract

Provided is a color filter inkjet ink composition from which can be formed a color filter pixel part having excellent external quantum efficiency, and that has excellent re-dispersibility, despite the composition containing luminescent nanocrystal particles and light-scattering particles. A color filter inkjet ink composition containing luminescent nanocrystal particles, an organic ligand capable of bonding with the surfaces of the luminescent nanocrystal particles, light-scattering particles, a polymer dispersant, and a photopolymerizable compound, the content of the organic ligand being 15-50 parts by mass with respect to 100 parts by mass of the luminescent nanocrystal particles, and the content of the polymer dispersant being 3-15 parts by mass with respect to 100 parts by mass of the light-scattering particles.

Description

Inkjet ink composition for color filter, cured product, light conversion layer, and color filter

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

Conventionally, color filters used in displays are, for example, red organic pigment particles or green organic pigment particles, using a curable resist material containing an alkali-soluble resin and / or an acrylic monomer, by photolithography. has been manufactured.

In recent years, there has been a strong demand for lower power consumption of displays, and instead of the red organic pigment particles or green organic pigment particles, for example, quantum dots, quantum rods, and other inorganic phosphor particles. A method of forming pixel portions such as red pixels and green pixels using .

By the way, the manufacturing method of the color filter by the photolithography method has the drawback that the resist material other than the pixel portion including the relatively expensive luminescent nanocrystal particles is wasted due to the characteristics of the manufacturing method. Under such circumstances, in order to eliminate the waste of the resist material as described above, it is being considered to form a light conversion layer using a curable ink composition by an inkjet method (inkjet method).

Japanese Patent No. 6754499

From the viewpoint of light conversion efficiency, etc., the inkjet ink composition for color filters may contain light-scattering particles together with luminescent nanocrystalline particles. However, in an ink composition containing luminescent nanocrystalline particles and light-scattering particles, aggregation of inorganic particle components tends to occur during storage, and the ability to redisperse homogeneously during use, so-called redispersibility, may deteriorate. was there.

The problem to be solved by the present invention is to form a color filter pixel portion having excellent external quantum efficiency while containing luminescent nanocrystalline particles and light-scattering particles, and a color filter having excellent redispersibility. An object of the present invention is to provide an inkjet ink composition for filters.

The present inventors have found that an inkjet ink composition for color filters containing luminescent nanocrystalline particles and light-scattering particles contains an organic ligand capable of binding to the surface of the luminescent nanocrystalline particles and a polymer dispersant. By containing each specific amount, it is possible to form a color filter pixel portion having excellent external quantum efficiency while containing light-emitting nanocrystalline particles and light-scattering particles, and a color excellent in redispersibility. It was found that a filter ink jet ink composition was obtained.

One aspect of the present invention comprises luminescent nanocrystalline particles, an organic ligand capable of binding to the surface of the luminescent nanocrystalline particles, a light scattering particle, a polymeric dispersant, and a photopolymerizable compound. , the content of the organic ligand is 15 to 50 parts by mass with respect to 100 parts by mass of the luminescent nanocrystalline particles, and the content of the polymer dispersant is 3 to 3 parts by mass with respect to 100 parts by mass of the light scattering particles. It relates to an inkjet ink composition for color filters, which is 15 parts by mass.

The molecular weight of the organic ligand is preferably 1000 or less.

The weight average molecular weight of the polymer dispersant is preferably 1000 or more. The polymeric dispersant preferably has both an acid value and an amine value. The polymer dispersant preferably contains two or more polymer dispersants.

The average particle size of the light-scattering particles is preferably 0.15 µm or more and 0.5 µm or less.

One aspect of the present invention relates to a cured product of the inkjet ink composition for color filters described above.

One aspect of the present invention includes a plurality of pixel portions and a light shielding portion provided between the plurality of pixel portions, and the plurality of pixel portions includes a cured product of the inkjet ink composition for a color filter. The present invention relates to a light conversion layer having an optical pixel portion.

The light conversion layer contains luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with an emission peak wavelength in the range of 605 to 665 nm as the luminescent pixel portion. and a second luminescent pixel portion containing luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with an emission peak wavelength in the range of 500 to 560 nm. Be prepared.

One 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 form a color filter pixel portion having excellent external quantum efficiency while containing luminescent nanocrystalline particles and light-scattering particles, and to obtain a color filter having excellent redispersibility. A filter inkjet ink composition can be provided.

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

Hereinafter, embodiments of the present invention will be described in detail. As used herein, the term “cured product of the ink composition” refers to a product obtained by curing a curable component in the ink composition (when the ink composition contains a solvent component, the ink composition after drying). is. Therefore, it is preferable that the cured product of the ink composition does not contain an organic solvent, but a part of the organic solvent that has not been dried may remain. Further, in the present specification, "non-volatile matter of the ink composition" means components other than the organic solvent contained in the ink composition. That is, the “non-volatile content of the ink composition” may be rephrased as a component before curing that should be contained in the cured product of the ink composition.

<Inkjet ink composition for color filters>
An inkjet ink composition for a color filter according to one embodiment (hereinafter also simply referred to as “ink composition”) comprises luminescent nanocrystalline particles, an organic ligand capable of binding to the surface of the luminescent nanocrystalline particles, and light scattering It contains organic particles, a polymer dispersant, and a photopolymerizable compound.

The ink composition is, for example, an ink composition for forming a light conversion layer (for example, for forming a pixel portion of a color filter) used for forming a light conversion layer (pixel portion of the light conversion layer) of a color filter. is. This ink composition is a composition used in an inkjet system. The ink composition of one embodiment is capable of forming a pixel portion (light conversion layer) without wasting expensive luminescent nanocrystalline particles, an inkjet head, etc., compared to the photolithographic method. It can contribute to finishing the inkjet method to a low-cost process. Hereinafter, embodiments of the ink composition will be described, taking as an example an ink composition that is used to form a light conversion layer by an inkjet method.

[Luminescent nanocrystalline particles]
Luminescent nanocrystalline particles are nano-sized crystals that absorb excitation light and emit fluorescence or phosphorescence. For example, the maximum particle diameter measured by a transmission electron microscope or scanning electron microscope is 100 nm or less. It is crystalline.

A luminescent nanocrystalline particle can, for example, emit light (fluorescence or phosphorescence) of a wavelength different from the absorbed wavelength by absorbing light of a predetermined wavelength. Luminescent nanocrystalline particles emit light having an emission peak wavelength in the range of 605-665 nm (red light), red-emitting nanocrystalline particles (red-emitting nanocrystalline particles), emission peak in the range of 500-560 nm green-emitting nanocrystalline particles (green-emitting nanocrystalline particles) that emit light having a wavelength (green light), or blue-emitting light that emits light having an emission peak wavelength in the range of 420-480 nm (blue light) It is preferable that the nanocrystalline particles (blue-emitting nanocrystalline particles) are used. In this embodiment, the ink composition preferably contains at least one of these luminescent nanocrystalline particles. In addition, the light absorbed by the luminescent nanocrystalline particles is, for example, light with a wavelength in the range of 400 nm or more and less than 500 nm (especially light in the wavelength range of 420 to 480 nm) (blue light), or in the range of 200 nm to 400 nm. (ultraviolet light). The emission peak wavelength of the luminescent nanocrystalline particles can be confirmed, for example, in the fluorescence spectrum or phosphorescence spectrum measured using a spectrofluorometer.

The red-emitting nanocrystalline particles are 665 nm or less, 663 nm or less, 660 nm or less, 658 nm or less, 655 nm or less, 653 nm or less, 651 nm or less, 650 nm or less, 647 nm or less, 645 nm or less, 643 nm or less, 640 nm or less, 637 nm or less, 635 nm or less. , 632 nm or less, or 630 nm or less, preferably 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 and lower limits can be combined arbitrarily. In addition, in the following similar description, the upper limit and the lower limit that are individually described can be arbitrarily combined.

Green-emitting nanocrystalline particles have an emission peak wavelength of 560 nm or less, 557 nm or less, 555 nm or less, 550 nm or less, 547 nm or less, 545 nm or less, 543 nm or less, 540 nm or less, 537 nm or less, 535 nm or less, 532 nm or less, or 530 nm or less. It preferably has an emission peak wavelength of 528 nm or more, 525 nm or more, 523 nm or more, 520 nm or more, 515 nm or more, 510 nm or more, 507 nm or more, 505 nm or more, 503 nm or more, or 500 nm or more.

The blue-emitting nanocrystalline particles have an emission peak wavelength of 480 nm or less, 477 nm or less, 475 nm or less, 470 nm or less, 467 nm or less, 465 nm or less, 463 nm or less, 460 nm or less, 457 nm or less, 455 nm or less, 452 nm or less, or 450 nm or less. It preferably has an emission peak wavelength of 450 nm or more, 445 nm or more, 440 nm or more, 435 nm or more, 430 nm or more, 428 nm or more, 425 nm or more, 422 nm or more, or 420 nm or more.

According to the solution of the Schrödinger wave equation of the well-type potential model, the wavelength (emission color) of the light emitted by the luminescent nanocrystalline particles depends on the size (e.g., particle diameter) of the luminescent nanocrystalline particles. It also depends on the energy gap of the crystal grains. Therefore, the emission color can be selected by changing the constituent material and size of the luminescent nanocrystalline particles used.

The luminescent nanocrystalline particles are preferably luminescent nanocrystalline particles containing a semiconductor material (luminescent semiconductor nanocrystalline particles). Luminescent semiconductor nanocrystal particles include quantum dots and quantum rods. Among these, quantum dots are preferable from the viewpoint that the emission spectrum can be easily controlled, the reliability can be secured, the production cost can be reduced, and the mass productivity can be improved.

The luminescent semiconductor nanocrystal particles may consist solely of a core comprising the first semiconductor material, comprising a core comprising the first semiconductor material and a second semiconductor material different from the first semiconductor material, wherein and a shell covering at least a portion of the core. In other words, the structure of the luminescent semiconductor nanocrystal particles is preferably a structure consisting of only a core (core structure) or a structure consisting of a core and a shell (core/shell structure). In addition, the luminescent semiconductor nanocrystal particle contains a third semiconductor material different from the first and second semiconductor materials in addition to the shell (first shell) containing the second semiconductor material, It may further have a shell (second shell) that covers at least part of it. In other words, the structure of the luminescent semiconductor nanocrystal particles is preferably a structure consisting of a core, a first shell and a second shell (core/shell/shell structure). Each of the core and shell can be a mixed crystal containing two or more semiconductor materials (eg, CdSe+CdS, CIS+ZnS, etc.).

Luminescent nanocrystalline particles are selected as semiconductor materials from the group consisting of II-VI semiconductors, III-V semiconductors, I-III-VI semiconductors, IV semiconductors and I-II-IV-VI semiconductors. It preferably contains at least one semiconductor material that

Specific semiconductor materials include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, ＣｄＺｎＴｅ、ＣｄＨｇＳ、ＣｄＨｇＳｅ、ＣｄＨｇＴｅ、ＨｇＺｎＳ、ＨｇＺｎＳｅ、ＣｄＨｇＺｎＴｅ、ＣｄＺｎＳｅＳ、ＣｄＺｎＳｅＴｅ、ＣｄＺｎＳＴｅ、ＣｄＨｇＳｅＳ、ＣｄＨｇＳｅＴｅ、ＣｄＨｇＳＴｅ、ＨｇＺｎＳｅＳ、ＨｇＺｎＳｅＴｅ、ＨｇＺｎＳＴｅ；ＧａＮ、ＧａＰ、ＧａＡｓ、ＧａＳｂ、ＡｌＮ、ＡｌＰ、ＡｌＡｓ、ＡｌＳｂ、ＩｎＮ、 InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb; SnPbSTe; includes Si, Ge, SiC, SiGe, AgInSe2, _CuGaSe2 , _CuInS2 , _CuGaS2 , _CuInSe2 , _AgInS2 , _AgGaSe2 , _AgGaS2 , _C , Si and Ge. Luminescent semiconductor nanocrystalline particles are CdS, CdSe, CdTe, ZnS, and CdS, CdSe, CdTe, ZnS, and CdS, CdSe, CdTe, ZnS, and CdS, CdSe, CdTe, ZnS, and CdS. ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, InP, InAs, InSb, GaP, GaAs, GaSb, _AgInS2 , _AgInSe2 , _AgInTe2 , _AgGaS2 , _AgGaSe2 , _AgGaTe2 , _CuInS2 , _CuInSe2 , _CuInTe , CuGaS ₂ , CuGaSe ₂ , CuGaTe ₂ , Si, C, Ge and Cu ₂ ZnSnS ₄ .

Examples of red-emitting semiconductor nanocrystal particles include nanocrystal particles of CdSe and nanocrystal particles having a core/shell structure in which the shell portion is CdS and the inner core portion is CdSe. particles, nanocrystalline particles with a core/shell structure, where the shell portion is CdS and the inner core portion is ZnSe, mixed crystal nanocrystalline particles of CdSe and ZnS, InP nanocrystalline particles A crystalline particle, a nanocrystalline particle with a core/shell structure, wherein the shell portion is ZnS and the inner core portion is InP, a nanocrystalline particle with a core/shell structure, Nanocrystalline particles whose shell portion is a mixed crystal of ZnS and ZnSe and whose inner core portion is InP, nanocrystalline particles of mixed crystal of CdSe and CdS, nanocrystalline particles of mixed crystal of ZnSe and CdS, core /Nanocrystalline particles with a shell/shell structure, wherein the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP, core/shell / A nanocrystalline particle having a shell structure, wherein the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and the inner core portion is InP etc.

Examples of green-emitting semiconductor nanocrystalline particles include nanocrystalline particles of CdSe, nanocrystalline particles of a mixed crystal of CdSe and ZnS, and nanocrystalline particles having a core/shell structure, the shell portion of which is ZnS. and a nanocrystalline particle having an inner core of InP, a nanocrystalline particle having a core/shell structure, wherein the shell is a mixed crystal of ZnS and ZnSe and the inner core is InP Crystalline particles, nanocrystalline particles with a core/shell/shell structure, wherein the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP , a nanocrystalline particle with a core/shell/shell structure, wherein the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and the inner core portion is InP certain nanocrystalline particles and the like.

Examples of blue-emitting semiconductor nanocrystalline particles include ZnSe nanocrystalline particles, ZnS nanocrystalline particles, and nanocrystalline particles having a core/shell structure, wherein the shell portion is ZnSe and the inner core portion is is ZnS, nanocrystalline particles of CdS, nanocrystalline particles having a core/shell structure, wherein the shell portion is ZnS and the inner core portion is InP, core/shell A nanocrystalline particle with a structure, wherein the shell part is a mixed crystal of ZnS and ZnSe and the inner core part is InP, a nanocrystalline particle with a core/shell/shell structure. a nanocrystalline particle having a first shell portion of ZnSe, a second shell portion of ZnS, and an inner core portion of InP, a nanocrystalline particle having a core/shell/shell structure, Examples include nanocrystalline particles in which the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and the inner core portion is InP.

With the same chemical composition, the semiconductor nanocrystal particles can change the color of light emitted from the particles to either red or green by changing the average particle size of the particles themselves. In addition, it is preferable to use semiconductor nanocrystal particles that themselves have the least adverse effect on the human body or the like. When semiconductor nanocrystal particles containing cadmium, selenium, etc. are used as luminescent nanocrystal particles, semiconductor nanocrystal particles that do not contain the above elements (cadmium, selenium, etc.) as much as possible are selected and used alone. is preferably used in combination with other luminescent nanocrystalline particles so as to minimize the

The shape of the luminescent nanocrystalline particles is not particularly limited, and may be any geometric shape or any irregular shape. Examples of the shape of the luminescent nanocrystalline particles include spherical, ellipsoidal, pyramidal, disk-like, branch-like, net-like, and rod-like. However, as the luminescent nanocrystalline particles, the uniformity and fluidity of the ink composition can be further enhanced by using particles with a less directional particle shape (e.g., spherical, regular tetrahedral particles, etc.). is preferred.

The average particle diameter (volume average diameter) of the luminescent nanocrystalline particles is 1 nm or more, 1.5 nm or more, or 2 nm from the viewpoint of easily obtaining light emission of a desired wavelength and from the viewpoint of excellent dispersibility and storage stability. It is preferable that it is above. From the viewpoint of easily obtaining a desired emission wavelength, the average particle size (volume average size) of the luminescent nanocrystalline particles is preferably 40 nm or less, 30 nm or less, or 20 nm or less. The average particle diameter (volume average diameter) of the luminescent nanocrystalline particles is obtained by measuring with a transmission electron microscope or scanning electron microscope and calculating the volume average diameter.

As the luminescent nanocrystalline particles, those dispersed in a colloidal form in a photopolymerizable compound or the like can be used. The surfaces of the dispersed luminescent nanocrystalline particles are preferably passivated with the above-described organic ligands.

Commercially available products can be used as the luminescent nanocrystalline particles. Commercially available luminescent nanocrystalline particles include, for example, indium phosphide/zinc sulfide, D-dot, CuInS/ZnS from NN-Labs, and InP/ZnS from Aldrich.

The content of the luminescent nanocrystalline particles is preferably 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, or 25 parts by mass or more with respect to 100 parts by mass of the nonvolatile matter of the ink composition. . In the present invention, it is noteworthy that the content of the luminescent nanocrystalline particles can be increased while exhibiting excellent suitability for the inkjet process. On the other hand, the content of the luminescent nanocrystalline particles is preferably 50 parts by mass or less, 45 parts by mass or less, or 40 parts by mass or less with respect to 100 parts by mass of the nonvolatile matter in the ink composition. As used herein, the content of luminescent nanocrystalline particles means the content of only the luminescent nanocrystalline particles themselves, and even if the luminescent nanocrystalline particles have organic ligands, the content of the organic ligands is Quantity not included.

The ink composition may contain, as luminescent nanocrystalline particles, two or more of red luminescent nanocrystalline particles, green luminescent nanocrystalline particles and blue luminescent nanocrystalline particles, but these are preferably used. It contains only one type of particles. When the ink composition comprises red-emitting nanocrystalline particles, the content of green-emitting nanocrystalline particles and the content of blue-emitting nanocrystalline particles are preferably 10, based on the total weight of the luminescent nanocrystalline particles. % by mass or less, more preferably 0% by mass. When the ink composition comprises green luminescent nanocrystalline particles, the content of red luminescent nanocrystalline particles and the content of blue luminescent nanocrystalline particles, based on the total mass of luminescent nanocrystalline particles, is preferably 10. % by mass or less, more preferably 0% by mass.

[Organic ligand]
The organic ligand is present near the surface of the luminescent nanocrystalline particles and has the function of dispersing the luminescent nanocrystalline particles. The organic ligand includes, for example, a functional group for ensuring affinity with a photopolymerizable compound (hereinafter also simply referred to as an “affinity group”) and a functional group capable of binding to a luminescent nanocrystal particle (light emitting functional group for ensuring adsorption to the luminescent nanocrystalline particles), and exists in the vicinity of the surface of the luminescent nanocrystalline particles by coordinating to the surface of the luminescent nanocrystalline particles.

The affinity group is preferably a substituted or unsubstituted aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear or have a branched structure. Also, the aliphatic hydrocarbon group may or may not have an unsaturated bond. The substituted aliphatic hydrocarbon may be a group in which some carbon atoms of an aliphatic hydrocarbon group are substituted with oxygen atoms. Substituted aliphatic hydrocarbon groups may include, for example, (poly)oxyalkylene groups. Here, the "(poly)oxyalkylene group" means at least one of an oxyalkylene group and a polyoxyalkylene group in which two or more alkylene groups are linked by an ether bond.

Functional groups that can be bonded to luminescent nanocrystalline particles include, for example, hydroxyl groups, amino groups, carboxyl groups, thiol groups, phosphoric acid groups, phosphonic acid groups, phosphine groups, phosphine oxide groups and alkoxysilyl groups.

The molecular weight of the organic ligand is preferably 1000 or less, more preferably 800 or less, 700 or less, 600 or less, or 500 or less. The organic ligand preferably has a molecular weight of, for example, 100 or more, or 200 or more. When the molecular weight of the organic ligand is within the above range, the viscosity as an inkjet ink is further improved.

Examples of organic ligands include TOP (trioctylphosphine), TOPO (trioctylphosphine oxide), oleic acid, linoleic acid, linolenic acid, ricinoleic acid, gluconic acid, 16-hydroxyhexadecanoic acid, 12-hydroxystearic acid, N - lauroylsarcosine, N-oleylsarcosine, oleylamine, octylamine, trioctylamine, hexadecylamine, octanethiol, dodecanethiol, hexylphosphonic acid (HPA), tetradecylphosphonic acid (TDPA), phenylphosphonic acid, and octylphosphine acid (OPA).

In one embodiment, the organic ligand is preferably an organic ligand represented by the following formula (1-1).

[In formula (1-1), p represents an integer of 0 to 50, and q represents an integer of 0 to 50. ]

In the organic ligand represented by formula (1-1), at least one of p and q is preferably 1 or more, more preferably both p and q are 1 or more.

The organic ligand may be, for example, an organic ligand represented by the following formula (1-2).

In formula (1-2), A ¹ represents a monovalent group containing a carboxyl group, A ² represents a monovalent group containing a hydroxy group, and R is a hydrogen atom, a methyl group, or an ethyl group. , L represents a substituted or unsubstituted alkylene group, and r represents an integer of 0 or more. The number of carboxyl groups in the monovalent group containing a carboxyl group is preferably 2 or more, more preferably 2 or more and 4 or less, and still more preferably 2. The alkylene group represented by L preferably has, for example, 1 to 10 carbon atoms. In the alkylene group represented by L, some of the carbon atoms may be substituted with hetero atoms, and substituted with at least one hetero atom selected from the group consisting of oxygen atoms, sulfur atoms and nitrogen atoms. good too. Preferably, r is, for example, an integer of 1-100 or an integer of 10-20.

The organic ligand is preferably, for example, an organic ligand represented by the following formula (1-2A).

In formula (1-2A), r has the same meaning as above.

In one embodiment, the organic ligand is preferably an organic ligand represented by the following formula (1-3).

In formula (1-3), n represents an integer of 0-50, and m represents an integer of 0-50. n is preferably 0-20, more preferably 0-10. m is preferably 0-20, more preferably 0-10. At least one of n and m is preferably 1 or more. That is, n+m is preferably 1 or more. n+m may be 10 or less. Z represents a substituted or unsubstituted alkylene group. The number of carbon atoms in the alkylene group may be, for example, 1-10. In the alkylene group represented by Z, some of the carbon atoms may be substituted with hetero atoms, and substituted with at least one hetero atom selected from the group consisting of oxygen atoms, sulfur atoms and nitrogen atoms. good too.

In one embodiment, the organic ligand is preferably an organic ligand represented by the following formula (1-4).

[In the formula (1-4), l represents an integer of 1 to 50. ]

In the organic ligand represented by formula (1-4), l is preferably 1-20, 3-15, 5-10, or 7.

The content of the organic ligand in the ink composition is 15 to 50 parts by mass with respect to 100 parts by mass of the luminescent nanocrystalline particles. The lower limit of the content of the organic ligand in the ink composition is from the viewpoint of further suppressing the aggregation of the components in the ink composition, from the viewpoint of further improving the effect of suppressing leakage light and improving the external quantum efficiency, and redispersion 16 parts by mass or more, 17 parts by mass or more, 18 parts by mass or more, 19 parts by mass or more, 20 parts by mass or more, 21 parts by mass or more, or 22 It is preferably at least 23 parts by mass or at least 23 parts by mass. The upper limit of the content of the organic ligand in the ink composition is 100 mass of the luminescent nanocrystalline particles from the viewpoint of further suppressing the occurrence of phase separation and/or gel-like matter and further improving the redispersibility. It is preferably 48 parts by mass or less, 46 parts by mass or less, 44 parts by mass or less, 42 parts by mass or less, 40 parts by mass or less, 38 parts by mass or less, or 36 parts by mass or less. From the viewpoint of further improving the effect of suppressing leakage light and improving the external quantum efficiency, and from the viewpoint of further improving the redispersibility, the content of the organic ligand in the ink composition is 100 parts by mass of the luminescent nanocrystalline particles. For example, it is preferably 18 to 45 parts by weight, 20 to 40 parts by weight, or 22 to 35 parts by weight.

[Light scattering particles]
Light-scattering particles are, for example, optically inactive inorganic fine particles. When the ink composition contains light-scattering particles, it is possible to scatter the light emitted from the light source with which the pixel portion is irradiated, so that excellent optical properties can be obtained.

Materials constituting the light-scattering particles include, for example, simple metals such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum, and gold; silica, barium sulfate, barium carbonate, calcium carbonate, Metal oxides such as talc, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, alumina white, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, zinc oxide; magnesium carbonate, barium carbonate, Metal carbonates such as bismuth subcarbonate and calcium carbonate; Metal hydroxides such as aluminum hydroxide; Composite oxides such as barium zirconate, calcium zirconate, calcium titanate, barium titanate and strontium titanate, bismuth subnitrate metal salts such as The light-scattering particles are selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate, barium titanate, and silica, from the viewpoint of excellent ejection stability and excellent effect of improving external quantum efficiency. It preferably contains at least one selected, and more preferably contains at least one selected from the group consisting of titanium oxide, zirconium oxide, zinc oxide and barium titanate.

The shape of the light-scattering particles may be spherical, filamentous, amorphous, or the like. However, as the light-scattering particles, the use of particles having a less directional particle shape (e.g., spherical, regular tetrahedral particles, etc.) improves the uniformity, fluidity, and light-scattering properties of the ink composition. It is preferable in that it can be increased and excellent ejection stability can be obtained.

The average particle size of the light-scattering particles in the ink composition is preferably 0.15 µm or more and 0.5 µm or less. The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition is, for example, 0.16 μm or more and 0.4 μm or less, 0.17 μm or more and 0.3 μm or less, or 0.18 μm or more and 0.25 μm or less. is preferably When the average particle size of the light-scattering particles in the ink composition is within the above range, the ejection stability of the inkjet ink is further improved. In this specification, the average particle diameter (volume average diameter) of the light scattering particles in the ink composition is obtained by measuring with a dynamic light scattering Nanotrack particle size distribution meter and calculating the volume average diameter. .

The content of the light-scattering particles is 0.1 parts by mass or more, 1 part by mass or more, 2 parts by mass or more, or 3 parts by mass or more with respect to 100 parts by mass of the nonvolatile matter of the ink composition. preferable. The content of the light-scattering particles is preferably less than 10 parts by mass, 9 parts by mass or less, 7 parts by mass or less, or 5 parts by mass or less with respect to 100 parts by mass of the nonvolatile matter of the ink composition.

The mass ratio of the content of light-scattering particles to the content of luminescent nanocrystalline particles (light-scattering particles/luminescent nanocrystalline particles) is 0.05 or more from the viewpoint of further improving the effect of improving the external quantum efficiency. It is preferably 0.07 or more, 0.1 or more, 0.13 or more, or 0.15 or more. The mass ratio (light-scattering particles/luminescent nanocrystalline particles) is 5.0 or less, 2.0 or less, 1.0 or less, 2.0 or less, and 1.0 or less, from the viewpoint of being more excellent in terms of suitability for inkjet processes, optical properties, and reproducibility thereof. It is preferably 0 or less, 0.5 or less, 0.2 or less, 0.19 or less, 0.18 or less, 0.17 or less, or 0.16 or less.

The total amount of the luminescent nanocrystalline particles and the light-scattering particles in the ink composition is 15 parts by mass with respect to 100 parts by mass of the nonvolatile content of the ink composition, from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink. Above, it is preferable that it is 20 mass parts or more, or 25 mass parts or more. The total amount of the luminescent nanocrystalline particles and the light-scattering particles in the ink composition is 60 parts by mass with respect to 100 parts by mass of the nonvolatile content of the ink composition, from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink. Hereinafter, it is preferably 50 parts by mass or less or 40 parts by mass or less.

[Polymer dispersant]
A polymeric dispersant is a polymeric compound having a weight average molecular weight of 750 or more and having a functional group having an affinity for light scattering particles. The polymer dispersant has a function of dispersing the light scattering particles. The polymer dispersant adsorbs to the light-scattering particles via a functional group having affinity for the light-scattering particles, and the light-scattering particles are dispersed by electrostatic repulsion and/or steric repulsion between the polymer dispersants. Disperse in the ink composition. When the ink composition contains a polymer dispersant, even when the content of the light-scattering particles is relatively large (for example, about 60% by mass), the light-scattering particles can be dispersed satisfactorily. can. The polymer dispersant is preferably bound to the surface of the light-scattering particles and adsorbed to the light-scattering particles, but is bound to the surface of the luminescent nanocrystalline particles and adsorbed to the luminescent nanocrystalline particles. may be free in the ink composition.

Functional groups that have affinity for light-scattering particles include acidic functional groups, basic functional groups, and nonionic functional groups. Acidic functional groups have dissociative protons and may be neutralized with bases such as amines and hydroxide ions, while basic functional groups are neutralized with acids such as organic acids and inorganic acids. may

Examples of acidic functional groups include carboxyl group (--COOH), sulfo group (--SO ₃ H), sulfate group (--OSO ₃ H), phosphonic acid group (--PO(OH) ₃ ), phosphoric acid group (--OPO ( OH) ₃ ), phosphinic acid group (--PO(OH)--), mercapto group (--SH).

Basic functional groups include primary, secondary and tertiary amino groups, ammonium groups, imino groups, and nitrogen-containing heterocyclic groups such as pyridine, pyrimidine, pyrazine, imidazole and triazole.

Nonionic functional groups include hydroxy group, ether group, thioether group, sulfinyl group (-SO-), sulfonyl group ( _-SO2- ), carbonyl group, formyl group, ester group, carbonate group, amide group, Carbamoyl group, ureido group, thioamide group, thioureido group, sulfamoyl group, cyano group, alkenyl group, alkynyl group, phosphine oxide group and phosphine sulfide group.

The polymeric dispersant is preferably a polymer (homopolymer) of a single monomer or a copolymer (copolymer) of multiple types of monomers. Moreover, the polymer dispersant may be a random copolymer, a block copolymer or a graft copolymer. When the polymeric dispersant is a graft copolymer, it is preferably a comb-shaped graft copolymer or a star-shaped graft copolymer. Examples of polymer dispersants include acrylic resins, polyester resins, polyurethane resins, polyamide resins, polyethers, phenol resins, silicone resins, polyurea resins, amino resins, epoxy resins, polyamines such as polyethyleneimine and polyallylamine, and polyimides. is mentioned.

The weight average molecular weight of the polymeric dispersant is 750 or more, preferably 1000 or more, 1500 or more, 2000 or more, or 3000 or more. The weight average molecular weight of the polymeric dispersant is preferably 40,000 or less, or 30,000 or less, for example. When the molecular weight of the polymer dispersant is within the above range (for example, 1000 or more), the dispersion stability of the light-scattering particles is excellent, and the ejection property of the inkjet ink is even more excellent. As used herein, the weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) under the following conditions.
Measuring device; HLC-8220GPC manufactured by Tosoh Corporation
Column; TSK-GUARDCOLUMN SuperHZ-L manufactured by Tosoh Corporation + TSK-GEL SuperHZM-M manufactured by Tosoh Corporation × 4
Detector; RI (differential refractometer)
Data processing; Multi-station GPC-8020modelII manufactured by Tosoh Corporation
Measurement conditions; column temperature 40°C
Solvent: Tetrahydrofuran Flow rate: 0.35 ml/min Standard: Monodisperse polystyrene Sample: A tetrahydrofuran solution of 0.2% by mass in terms of resin solid content filtered through a microfilter (100 μl)

The polymer dispersant is preferably a compound having at least a basic functional group. That is, the polymeric dispersant preferably has an amine value. The amine value of the polymer dispersant is preferably 0.1 mgKOH/g or more, 1 mgKOH/g or more, 5 mgKOH/g or more, or 10 mgKOH/g or more. The amine value of the polymeric dispersant is preferably 120 mgKOH/g or less, 100 mgKOH/g or less, 90 mgKOH/g or less, or 80 mgKOH/g or less.

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

The polymer dispersant preferably has an acid value, more preferably both an acid value and an amine value. The acid value of the polymer dispersant is, for example, preferably 0 mgKOH/g or more, or 10 mgKOH/g or more, and preferably 70 mgKOH/g or less, 60 mgKOH/g or less, or 50 mgKOH/g or less.

Acid value can be measured as follows. A sample solution was prepared by dissolving pg of a polymer dispersant and 1 mL of a phenolphthalein test solution in 50 mL of a mixed solution in which toluene and ethanol were mixed at a volume ratio of 1:1, and a 0.1 mol / L ethanolic potassium hydroxide solution. (Dissolve 7.0 g of potassium hydroxide in 5.0 mL of distilled water and adjust the volume to 1000 mL by adding 95 vol% ethanol) until the sample solution turns pale red, and the acid value is calculated by the following formula. can be calculated.
Acid value = q x r x 5.611/p
In the formula, q represents the titration amount (mL) of the 0.1 mol/L ethanol potassium hydroxide solution required for titration, and r represents the titer of the 0.1 mol/L ethanol potassium hydroxide solution required for titration. and p indicates the mass (g) of the polymer dispersant.
Examples of the polymer dispersant having an acid value and an amine value include a dispersant having a linear aliphatic polyester skeleton and an aliphatic polyether skeleton as a basic skeleton and having a carboxyl group and an amino group, and an arylamine. Copolymers of moieties, maleic acid and amino group-containing maleic acid, copolymers of polyarylamine and aliphatic polyester, and the like.

The polymeric dispersant may be used singly or in combination of two or more. The polymeric dispersant preferably contains two or more polymeric dispersants.

Commercially available products can be used as the polymer dispersant, and commercial products include Ajinomoto Fine-Techno Co., Inc.'s Ajisper PB series, BYK's DISPERBYK series and BYK-series, and BASF's Efka series. , Solsperse S24000GR manufactured by Nippon Lubrizol Co., Ltd., or the like can be used.

The content of the polymer dispersant in the ink composition is 3 to 15 parts by mass with respect to 100 parts by mass of the light-scattering particles. The lower limit of the content of the polymer dispersant in the ink composition is from the viewpoint of further suppressing the aggregation of the components in the ink composition, from the viewpoint of being more excellent in the effect of suppressing leakage light and the effect of improving the external quantum efficiency, and From the viewpoint of further excellent redispersibility, it is preferably 4 parts by mass or more or 5 parts by mass or more with respect to 100 parts by mass of the light-scattering particles. The upper limit of the content of the polymer dispersant in the ink composition is 13 parts by mass or less, from the viewpoint of further suppressing deterioration of the luminescent nanocrystalline particles and from the viewpoint of further improving the effect of improving the external quantum efficiency. It is preferably 11 parts by mass or less, 9 parts by mass or less, or 7 parts by mass or less. From the above-described viewpoint, the content of the polymer dispersant in the ink composition is, for example, 3 to 13 parts by mass, 3 to 11 parts by mass, 4 to 9 parts by mass, or It is preferably 4 to 7 parts by mass.

[Photopolymerizable compound]
A photopolymerizable compound is a compound that polymerizes when irradiated with light. The photopolymerizable compound is preferably, for example, a photoradical polymerizable compound. The photopolymerizable compound is preferably a photopolymerizable monomer or oligomer. A photopolymerizable compound is used together with a photopolymerization initiator. A photoradical polymerizable compound is used together with a photoradical polymerization initiator. In other words, the ink composition may contain a photopolymerizable component containing a photopolymerizable compound and a photopolymerization initiator, and contains a photoradical polymerizable component containing a photoradical polymerizable compound and a photoradical polymerization initiator. You may have The ink composition may contain one type of photopolymerizable compound, may contain two or more types, and preferably contains two or more types.

Examples of photoradical polymerizable compounds include monomers having ethylenically unsaturated groups (hereinafter also referred to as "ethylenically unsaturated monomers"), monomers having isocyanate groups, and the like. Here, the ethylenically unsaturated monomer means a monomer having an ethylenically unsaturated bond (carbon-carbon double bond).

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

The ethylenically unsaturated group is preferably a vinyl group, a vinylene group, a vinylidene group, a (meth)acryloyl group, or the like, and more preferably a (meth)acryloyl group. In addition, in this specification, a "(meth)acryloyl group" means an "acryloyl group" and a "methacryloyl group" corresponding thereto. The same applies to expressions such as “(meth)acrylate” and “(meth)acrylamide”.

The photopolymerizable compound preferably contains at least one compound having a (meth)acryloyl group as an ethylenically unsaturated group, more preferably at least one selected from the group consisting of (meth)acrylates and (meth)acrylamides. One type is included, more preferably at least one type of (meth)acrylate is included, and at least one type of (meth)acrylate with a linear alkyl group having 8 or more carbon atoms is particularly preferably included. The photopolymerizable compound preferably contains two or more (meth)acrylates from the viewpoint of facilitating both excellent ejection stability and excellent curability and from the viewpoint of further improving the external quantum efficiency. , More preferably, a (meth)acrylate having one (meth)acryloyl group (monofunctional (meth)acrylate) and a (meth)acrylate having two or more (meth)acryloyl groups (polyfunctional (meth)acrylate) More preferably, monofunctional (meth) acrylate, (meth) acrylate having two (meth) acryloyl groups (bifunctional (meth) acrylate) and (meth) having three acryloyl groups (meth) and at least one selected from the group consisting of acrylates (trifunctional (meth)acrylates). From the viewpoint of further improving optical properties (for example, wavelength control), the photopolymerizable compound preferably contains a (meth)acrylate having a hydroxy group.

Examples of monofunctional monomers include lauryl (meth)acrylate, glycerin mono(meth)acrylate, 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, methoxyethyl (meth) Acrylates, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate Acrylates, methoxytriethylene glycol (meth)acrylate, butoxydiethylene glycol (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, phenylbenzyl (meth)acrylate, succinic acid mono(2- acryloyloxyethyl), mono(2-methacryloyloxyethyl) succinate, N-[2-(acryloyloxy)ethyl]phthalimide, N-[2-(acryloyloxy)ethyl]tetrahydrophthalimide, 4-hydroxybutyl acrylate, 2 -hydroxypropyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, diacetoneacrylamide, 4-acryloylmorpholine, N-tert-butylacrylamide, N- hydroxymethylacrylamide, N-hydroxyethylacrylamide, N-tert-octylacrylamide, N-butoxymethylacrylamide, N-phenylacrylamide, N-dodecylacrylamide, etc. mentioned.

Specific examples of monomers having two ethylenically unsaturated groups (bifunctional monomers) include 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-pentane Diol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,8-octanediol Di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) ) acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol hydroxypivalate diacrylate, tris(2-hydroxyethyl ) Two diols obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol and di(meth)acrylate in which two hydroxyl groups of isocyanurate are substituted by (meth)acryloyloxy groups. di(meth)acrylate in which the hydroxyl group of is substituted by a (meth)acryloyloxy group, and two hydroxyl groups of the diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A are (meth)acryloyloxy groups A di(meth)acrylate substituted with a triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane, and two hydroxyl groups of the triol are substituted with a (meth)acryloyloxy group ( meth)acrylate, di(meth)acrylate obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A and two hydroxyl groups of the diol are substituted with (meth)acryloyloxy groups, N,N' -methylenebisacrylamide, N,N'-ethylenebisacrylamide, and the like.

Specific examples of monomers having three ethylenically unsaturated groups (trifunctional monomers) include glycerin tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and EO-modified trimethylol. propane tri(meth)acrylate and the like.

The photopolymerizable compound is preferably alkali-insoluble from the viewpoint of easily obtaining a highly reliable pixel portion (cured product of the ink composition). In the present specification, the photopolymerizable compound being alkali-insoluble means that the amount of the photopolymerizable compound dissolved in a 1% by mass aqueous potassium hydroxide solution at 25° C. is 30, based on the total mass of the photopolymerizable compound. % or less. The dissolved amount of the photopolymerizable compound is preferably 10% by mass or less, more preferably 3% by mass or less.

The content of the photopolymerizable compound is determined from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink, the viewpoint of good curability of the ink composition, and the solvent resistance and From the viewpoint of improving abrasion resistance, it is preferably 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more with respect to 100 parts by mass of the nonvolatile matter of the ink composition. The content of the photopolymerizable compound is 100% by mass of the non-volatile matter of the ink composition from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink and from the viewpoint of obtaining better optical properties (e.g., external quantum efficiency). It is preferably 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less.

In the ink composition of the present embodiment, since the photopolymerizable compound also functions as a dispersion medium, it is possible to disperse the light-scattering particles and the luminescent nanocrystalline particles without a solvent. In this case, there is an advantage that the step of removing the solvent by drying is not required when forming the pixel portion.

[Photoinitiator]
The ink composition may further contain a photopolymerization initiator. A photoinitiator is used together with a photopolymerizable compound. The photopolymerization initiator is, for example, a photoradical polymerization initiator or a photocationic polymerization initiator. As the photoradical polymerization initiator, a molecular cleavage type or hydrogen abstraction type photoradical polymerization initiator is suitable.

Molecular cleavage type photoradical polymerization initiators include benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2-benzyl-2-dimethylamino-1. -(4-morpholinophenyl)-butan-1-one, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide etc. are preferably used. Other molecular cleavage type radical photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4 -isopropylphenyl)-2-hydroxy-2-methylpropan-1-one and 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one may be used in combination.

Benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4'-methyl-diphenyl sulfide and the like are examples of hydrogen abstraction type photoradical polymerization initiators. A molecular cleavage type radical photopolymerization initiator and a hydrogen abstraction type photoradical polymerization initiator may be used in combination.

A commercial product can also be used as a photocationic polymerization initiator. Commercially available products include sulfonium salt photocationic polymerization initiators such as "CPI-100P" manufactured by San-Apro, acylphosphine oxide compounds such as "Lucirin TPO" manufactured by BASF, "Irgacure 907" manufactured by BASF, "Irgacure 819", "Irgacure 379EG", "Irgacure 184" and "Irgacure PAG290".

From the viewpoint of the curability of the ink composition, the content of the photopolymerization initiator is 0.1 parts by mass or more, 0.5 parts by mass or more, 1 part by mass or more, 3 parts by mass or more, relative to 100 parts by mass of the photopolymerizable compound. It is preferably at least 5 parts by mass, or at least 5 parts by mass. The content of the photopolymerization initiator is 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass with respect to 100 parts by mass of the photopolymerizable compound, from the viewpoint of the temporal stability of the pixel portion (cured product of the ink composition). parts or less, or preferably 10 parts by mass or less.

The ink composition contains components other than the components described above (for example, organic solvents, thermosetting resins, curing agents, curing accelerators (curing catalysts), polymerization inhibitors, chain transfer agents, and , antioxidants, etc.) may be further contained.

The viscosity of the ink composition described above at the ink temperature during inkjet printing is preferably, for example, 2 mPa·s or more, 5 mPa·s or more, or 7 mPa·s or more from the viewpoint of ejection stability during inkjet printing. . The viscosity of the ink composition at the ink temperature during inkjet printing is preferably 20 mPa·s or less, 15 mPa·s or less, or 12 mPa·s or less. In this specification, the viscosity of the ink composition is measured at 25° C., for example, by an E-type viscometer.

When the viscosity of the ink composition at the ink temperature during inkjet printing is 2 mPa s or more, the meniscus shape of the inkjet ink at the tip of the ink ejection hole of the ejection head is stabilized. control of the amount and timing of ejection) becomes easier. On the other hand, when the viscosity of the ink composition at the ink temperature during inkjet printing is 20 mPa·s or less, the inkjet ink can be smoothly ejected from the ink ejection holes.

The surface tension of the ink composition is preferably a surface tension suitable for an inkjet system, specifically preferably in the range of 20 to 40 mN/m, more preferably 25 to 35 mN/m. . By setting the surface tension within this range, it is possible to facilitate ejection control (for example, control of ejection amount and ejection timing) and to suppress the occurrence of flight deflection. The term "flight deflection" means that when the ink composition is ejected from the ink ejection holes, the landing position of the ink composition deviates from the target position by 30 μm or more. When the surface tension is 40 mN/m or less, the meniscus shape at the tip of the ink ejection hole is stabilized, so that the ejection control of the ink composition (for example, control of ejection amount and ejection timing) becomes easy. On the other hand, when the surface tension is 20 mN/m or more, contamination of the periphery of the ink ejection holes with the ink jet ink can be prevented, so that the occurrence of flight deflection can be suppressed. That is, the ink composition is not accurately deposited on the pixel portion forming region where the ink composition should be deposited, resulting in an insufficiently filled pixel portion, or the pixel portion forming region (or pixel portion) adjacent to the pixel portion forming region where the ink composition should be deposited. The ink composition does not land on the surface, and the color reproducibility is not deteriorated. The surface tension described in the specification of the present application refers to the surface tension measured at 23° C., which is measured by the ring method (also referred to as the ring method).

The ink composition of the present embodiment is preferably applied to a piezojet type inkjet recording apparatus with a mechanical ejection mechanism using a piezoelectric element. In the piezo jet method, the ink composition is not instantaneously exposed to high temperatures during ejection. Therefore, the luminescent nanocrystalline particles are less likely to be degraded, and expected luminous properties can be more easily obtained in the pixel portion (light conversion layer).

<Method for producing ink composition>
The ink composition of the embodiment described above includes, for example, a step of mixing the components of the ink composition described above. The method for producing the ink composition may further comprise a step of dispersing the mixture of the above components.

A method for producing an ink composition includes, for example, a dispersion of light-scattering particles containing light-scattering particles and a polymer dispersant, and a dispersion of light-emitting nanocrystal particles containing light-emitting nanocrystal particles and an organic ligand. and mixing. According to this method, it is possible to improve the optical properties of the pixel portion (improvement of external quantum efficiency, suppression of leakage light, etc.) and to obtain an ink composition excellent in redispersibility.

In the method for producing the ink composition, before the step of mixing the dispersion of light-scattering particles and the dispersion of luminescent nanocrystalline particles, light-scattering particles, a polymer dispersant and a photopolymerizable compound are added. A step of providing a dispersion of light-scattering particles to be contained may be provided. In the step of preparing a dispersion of light-scattering particles, light-scattering particles, a polymer dispersant, and a photopolymerizable compound are mixed and subjected to dispersion treatment to prepare a dispersion of light-scattering particles. You can Mixing and dispersing treatments may be carried out using dispersing equipment such as bead mills, paint conditioners, planetary stirrers, jet mills and the like. It is preferable to use a bead mill or a paint conditioner from the viewpoint of improving the dispersibility of the light-scattering particles and facilitating adjustment of the average particle size of the light-scattering particles to a desired range.

A method for producing an ink composition comprises mixing luminescent nanocrystalline particles, an organic ligand, and a photopolymerizable compound before the step of mixing a dispersion of light-scattering particles and a dispersion of luminescent nanocrystalline particles. and the step of providing a dispersion of luminescent nanocrystalline particles. In the step of preparing a dispersion of luminescent nanocrystalline particles, luminescent nanocrystalline particles, a photopolymerizable compound, and an organic ligand are mixed, and dispersion treatment is performed to prepare a dispersion of luminescent nanocrystalline particles. You can Mixing and dispersion treatment may be carried out using ordinary stirring devices such as an electromagnetic stirrer and a three-one motor, and dispersion devices such as a vortex mixer, a bead mill, a paint conditioner, a planetary stirrer and a jet mill. From the viewpoint of not applying excessive energy to the luminescent nanocrystalline particles, it is preferable to use a normal stirring device such as an electromagnetic stirrer or a three-one motor, or a vortex mixer. According to this method, it is possible to sufficiently disperse the luminescent nanocrystalline particles without deteriorating their performance. Therefore, it is possible to improve the optical properties of the pixel portion (improved external quantum efficiency, suppress leaked light, etc.), and obtain an ink composition having excellent redispersibility.

<Ink composition set>
An ink composition set of one embodiment includes the ink composition of the embodiment described above. The ink composition set may include an ink composition that does not contain luminescent nanocrystalline particles (non-luminescent ink composition) in addition to the ink composition (luminescent ink composition) of the embodiment described above. A non-luminescent ink composition is, for example, a curable ink composition. The non-luminescent ink composition may be a conventionally known ink composition, and has the same composition as the ink composition (luminescent ink composition) of the above-described embodiment except that it does not contain luminescent nanocrystalline particles. may be

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

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

<Light conversion layer and color filter>
Hereinafter, details of the light conversion layer and the color filter obtained using the ink composition set of the embodiment described above will be described with reference to the drawings. In the following description, the same reference numerals are used for the same or corresponding elements, and overlapping descriptions are omitted.

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

The light conversion layer 30 has, as pixel sections 10, a first pixel section 10a, a second pixel section 10b, and a third pixel section 10c. The first pixel section 10a, the second pixel section 10b, and the third pixel section 10c are arranged in a grid so as to repeat this order. The light shielding 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. is provided between the first pixel portion 10c and the first pixel portion 10a. In other words, these adjacent pixel portions are separated by the light shielding portion 20 .

The first pixel portion 10a and the second pixel portion 10b are luminescent pixel portions (luminescent pixel portions) each containing a cured product of the ink composition of the embodiment described above. The first pixel portion 10a includes a first curing component 13a, and first luminescent nanocrystalline 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 nanocrystalline particles 11b and second light scattering particles 12b dispersed in the second curing component 13b, respectively. including. A curing component is a component obtained by polymerization of a photopolymerizable compound, and includes a polymer of the photopolymerizable compound, an organic ligand and a polymer dispersant. The curing component may further contain an organic component (such as an unreacted photopolymerizable compound) contained in the ink composition. In the first pixel portion 10a and the second pixel portion 10b, the first curing component 13a and the second curing component 13b may be the same or different, and may be the first light scattering particles 12a. It may be the same as or different from the second light scattering particles 12b.

The first luminescent nanocrystalline particles 11a are red luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420-480 nm and emit light with an emission peak wavelength in the range of 605-665 nm. That is, the first pixel section 10a can be rephrased as a red pixel section for converting blue light into red light. The second luminescent nanocrystalline particles 11b are green luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with an emission peak wavelength in the range of 500 to 560 nm. That is, the second pixel section 10b can be rephrased as a green pixel section for converting blue light into green light.

The content of the luminescent nanocrystalline particles in the luminescent pixel portion is based on the total mass of the cured luminescent ink composition, from the viewpoint of obtaining an excellent effect of improving the external quantum efficiency and obtaining excellent emission intensity. It is preferably 15% by mass or more, 18% by mass or more, 20% by mass or more, or 24% by mass or more. The content of the luminescent nanocrystalline particles is preferably 80% by mass or less based on the total mass of the cured luminescent ink composition, from the viewpoint of obtaining excellent reliability of the pixel portion and excellent emission intensity. , 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less.

The content of the light-scattering particles in the light-emitting pixel portion is, for example, 0.1% by mass or more based on the total mass of the cured product of the light-emitting ink composition, from the viewpoint of improving the external quantum efficiency. , 1% by mass or more, or 2% by mass or more. The content of the light-scattering particles is preferably, for example, 60% by mass or less based on the total mass of the cured luminescent ink composition. The content of the light-scattering particles is preferably 10% by mass or less based on the total mass of the cured luminescent ink composition, from the viewpoint of improving the external quantum efficiency and the reliability of the pixel portion. , more preferably 7% by mass or less, and still more preferably 5% by mass or less.

The third pixel portion 10c is a non-luminous pixel portion (non-luminous pixel portion) containing the cured non-luminous ink composition described above. The cured product does not contain luminescent nanocrystalline particles, but contains light-scattering particles and a curing component. That is, the third pixel portion 10c includes a third curing component 13c and third light scattering particles 12c dispersed in the third curing component 13c. The third curing component 13c is, for example, a component obtained by polymerizing a polymerizable compound, and 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.

For example, the third pixel section 10c has a transmittance of 30% or more for light with a wavelength in the range of 420 to 480 nm. Therefore, the third pixel section 10c functions as a blue pixel section when using a light source that emits light with a wavelength in the range of 420 to 480 nm. Note that the transmittance of the third pixel section 10c can be measured with a microspectroscope.

The content of the light-scattering particles in the non-luminous pixel portion is 1% by mass based on the total mass of the cured non-luminous ink composition, from the viewpoint of further reducing the difference in light intensity at viewing angles. Above, it is preferable that it is 5 mass % or more, or 10 mass % or more. From the viewpoint of further reducing light reflection, the content of the light-scattering particles is 50% by mass or less, 30% by mass or less, or 20% by mass, based on the total mass of the cured non-luminescent ink composition. % or less.

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

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

The base material 40 is a transparent base material having optical transparency. A flexible base material or the like can be used. Among these, it is preferable to use a glass substrate made of alkali-free glass that does not contain an alkali component. Specifically, "7059 glass", "1737 glass", "Eagle 200" and "Eagle XG" manufactured by Corning, "AN100" manufactured by Asahi Glass Co., Ltd., "OA-10G" manufactured by Nippon Electric Glass Co., Ltd. and " OA-11” is preferred. These materials have a small coefficient of thermal expansion and are excellent in dimensional stability and workability in high-temperature heat treatment.

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

The color filter 100 can be manufactured, for example, by forming the light-shielding portions 20 in a pattern on the substrate 40 and then forming the pixel portions 10 in the pixel-forming regions partitioned by the light-shielding portions 20 on the substrate 40. . The pixel portion 10 is formed by a method comprising a step of selectively applying an ink composition to a pixel portion forming region on the substrate 40 by an inkjet method, and a step of curing the ink composition to obtain a luminescent pixel portion. can be formed. A luminescent pixel portion can be obtained by using the luminescent ink composition described above as the ink composition, and a non-luminescent pixel portion can be obtained by using a non-luminescent ink composition.

The method of forming the light shielding portion 20 is to form a thin film of a metal such as chromium or a thin film of a resin composition containing light shielding particles in a region that serves as a boundary between a plurality of pixel portions on one side of the substrate 40. and a method of patterning this thin film. The metal thin film can be formed, for example, by a sputtering method, a vacuum deposition method, or the like, and the thin film of the resin composition containing light-shielding particles can be formed, for example, by a method such as coating or printing. As a method for patterning, a photolithography method or the like can be used.

Examples of the ink jet method include the bubble jet (registered trademark) method using an electrothermal transducer as an energy generating element, and the piezo jet method using a piezoelectric element.

Curing of the ink composition may be performed by irradiating with active energy rays (eg, ultraviolet rays). For curing the ink composition, for example, a mercury lamp, a metal halide lamp, a xenon lamp, an LED, or the like may be used. It is preferable that the wavelength of the light to be irradiated is, for example, 200 nm or more or 440 nm or less. The exposure dose is preferably, for example, 10 mJ/cm ² or more, or 20000 mJ/cm ² or less.

Although one embodiment of the color filter, the light conversion layer, and the manufacturing method thereof has been described above, the present invention is not limited to the above embodiment.

For example, the light conversion layer may be a pixel portion ( blue pixel portion). In addition, the light conversion layer may include pixel portions (e.g., yellow pixel portions) containing a cured product of a luminescent ink composition containing nanocrystalline particles that emit light of a color other than red, green, and blue. good. In these cases, each of the luminescent nanocrystalline particles contained in each pixel portion of the light conversion layer preferably has a maximum absorption wavelength in the same wavelength range.

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

In addition, the color filter may have an ink-repellent layer made of an ink-repellent material having a narrower width than the light-shielding portion on the pattern of the light-shielding portion. Further, instead of providing an ink-repellent layer, a photocatalyst-containing layer as a variable wettability layer is formed in a solid manner in a region including a pixel portion forming region, and then light is applied to the photocatalyst-containing layer through a photomask. By irradiating and exposing, the ink affinity of the pixel portion forming region may be selectively increased. Examples of photocatalysts include titanium oxide and zinc oxide.

In addition, the color filter may have an ink-receiving layer containing hydroxypropylcellulose, polyvinyl alcohol, gelatin, etc. between the base material and the pixel portion.

Also, the color filter may have a protective layer on the pixel portion. This protective layer flattens the color filter and prevents components contained in the pixel portion, or components contained in the pixel portion and components contained in the photocatalyst-containing layer from eluting into the liquid crystal layer. It is provided. Materials used for known color filter protective layers can be used for the protective layer.

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

Further, one or two of 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 are A pixel portion containing a coloring material without containing crystal grains may be used. As the coloring material that can be used here, known coloring materials can be used. For example, the coloring material used in the red pixel portion (R) includes a diketopyrrolopyrrole pigment and/or an anionic red organic dye. mentioned. The coloring material used in the green pixel portion (G) includes at least one selected from the group consisting of halogenated copper phthalocyanine pigments, phthalocyanine green dyes, and mixtures of phthalocyanine blue dyes and azo yellow organic dyes. Coloring materials used in the blue pixel portion (B) include ε-type copper phthalocyanine pigments and/or cationic blue organic dyes. When these colorants are contained in the light conversion layer, the amount used is 1 to 5 masses based on the total mass of the pixel portion (cured product of the ink composition) from the viewpoint of preventing a decrease in transmittance. %.

In addition, the color filter may include a normal color filter layer containing the above-described colorant without containing the luminescent nanocrystalline particles between the base material and the pixel portion of the present embodiment. That is, the color filter of the present embodiment includes a base material, a color filter layer containing a colorant and not containing luminescent nanocrystal particles, provided on the base material, and provided on the color filter layer, and the pixel portion of the present embodiment.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited only to the following examples. All the materials used in the examples were obtained by introducing argon gas to replace dissolved oxygen with argon gas. The liquid materials used in the examples were dehydrated with molecular sieves 3A for 48 hours or more before mixing.

<Preparation of photopolymerizable compound>
Photopolymerizable compounds shown in Table 1 were prepared.

Example 1
<Preparation of QD powder A>
[Synthesis of organic ligand 1]
After introducing polyethylene glycol |average Mn350| (manufactured by Sigma-Aldrich) into the flask, while stirring in a nitrogen gas environment, polyethylene glycol |average Mn350| made) was added. The internal temperature of the flask was raised to 80° C. and stirred for 8 hours to obtain an organic ligand 1 represented by the following formula (A) as a pale yellow aged oil.

[Preparation of QD powder A by ligand exchange]
Nanosys InP nanocrystal dispersion (InP QD in Heptane Red InP QD, QD particles (luminescent nanocrystal particles) concentration 30%, organic ligand: oleic acid), 2.0 times the amount of PGMEA and QD Ligand exchange was performed by adding organic ligand 1 in an amount corresponding to 35% by mass with respect to the amount of particles (excluding the amount of organic ligand) and stirring at 80° C. for 1 hour. By adding four times the amount of heptane to this solution, the QD particles were aggregated and precipitated by centrifugation, and then the QD particles were separated by decanting the supernatant. The resulting QD particles were dried in a vacuum dryer to obtain red-light-emitting QD powder A (QD particles/organic ligand=76% by mass/24% by mass).

<Preparation of Light-scattering Particle Dispersion A>
In a container filled with argon gas, 8.0 g of titanium oxide (trade name: PF-690, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 210 nm) and a polymer dispersant (trade name: PB -821, manufactured by Ajinomoto Fine-Techno Co., Ltd.) and 11.6 g of phenoxyethyl acrylate (trade name: Light Acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.) were mixed. After that, zirconia beads (diameter: 0.03 mm) were added to the obtained mixture, and the mixture was subjected to dispersion treatment by shaking for 4 hours using a paint conditioner. Then, the zirconia beads were removed from the mixture with a polyester mesh filter to obtain a light-scattering particle dispersion.

<Preparation of Ink Composition of Example 1>
1.71 g of QD powder A, 0.52 g of light scattering particle dispersion A, and a photopolymerization initiator (phenyl (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, manufactured by IGM resin, Product name: Omnirad TPO) 0.30 g, a mixture of photopolymerizable compounds (PhEM: LM: HDMMA = 43: 22: 35 (mass ratio)) 2.37 g, a hindered phenolic antioxidant (BASF Japan Co., Ltd., product name: Irganox 1010) 0.05 g, and after uniformly mixing in a container filled with argon gas, the mixture was filtered through a filter with a pore size of 5 μm in a glove box. The obtained filtrate was introduced into a container containing the filtrate, and the inside of the container was saturated with argon gas, and then the pressure was reduced to remove the argon gas, thereby obtaining an ink composition of Example 1.

Example 2
<Preparation of QD powder B by ligand exchange>
Nanosys InP nanocrystal dispersion (InP QD in Heptane Green InP QD, QD particles (luminescent nanocrystal particles) concentration 30%, organic ligand: oleic acid), 2.0 times the amount of PGMEA and QD Ligand exchange was carried out by adding organic ligand 1 in an amount corresponding to 40% by mass with respect to the amount of particles (excluding the amount of organic ligand) and stirring at 80° C. for 1 hour. By adding four times the amount of heptane to this solution, the QD particles were aggregated and precipitated by centrifugation, and then the QD particles were separated by decanting the supernatant. The obtained QD particles were dried in a vacuum dryer to obtain a green-emitting QD powder B (QD particles/organic ligand=66% by mass/34% by mass).

<Preparation of Ink Composition of Example 2>
1.71 g of QD powder B, 0.59 g of light scattering particle dispersion, and a photopolymerization initiator (phenyl (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, manufactured by IGM resin, product Name: Omnirad TPO) 0.12 g, a mixture of photopolymerizable compounds (PhEM: LA: HDMMA = 39: 23: 38 (mass ratio)) 2.39 g, a hindered phenolic antioxidant (BASF Japan 0.05 g of Irganox 1010 (manufactured by Irganox 1010) was blended and uniformly mixed in a container filled with argon gas, and then the mixture was filtered through a filter with a pore size of 5 μm in a glove box. The obtained filtrate was introduced into a container containing the filtrate, the inside of the container was saturated with argon gas, and the pressure was reduced to remove the argon gas, thereby obtaining an ink composition of Example 2.

Example 3
<Preparation of Light-scattering Particle Dispersion B>
In a container filled with argon gas, 8.0 g of titanium oxide (trade name: PF-690, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 210 nm) and a polymer dispersant (trade name: PB -821, manufactured by Ajinomoto Fine-Techno Co., Ltd.) and 11.2 g of phenoxyethyl acrylate (trade name: Light Acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.) were mixed. After that, zirconia beads (diameter: 0.03 mm) were added to the obtained mixture, and the mixture was subjected to dispersion treatment by shaking for 4 hours using a paint conditioner. Then, the zirconia beads were removed from the mixture with a polyester mesh filter to obtain a light-scattering particle dispersion.

<Preparation of Ink Composition of Example 3>
Light-scattering particle dispersion B was used instead of light-scattering particle dispersion A, GLM was added to the mixture of photopolymerizable compounds, and the weight ratio PhEM:LA:HDDMA:GLM = 34:22:38:6. An ink composition of Example 3 was prepared in the same manner as in Example 2, except that

Example 4
<Preparation of Light-scattering Particle Dispersion C>
In a container filled with argon gas, 8.0 g of titanium oxide (trade name: PF-690, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 210 nm) and a polymer dispersant (trade name: PB -821, Ajinomoto Fine-Techno Co., Inc., amine value: 10, acid value: 17) 0.4 g, and a polymer dispersant (trade name: Solsperse S24000GR, manufactured by Nippon Lubrizol Co., Ltd., amine value: 42, acid value : 26) 0.4 g and 11.2 g of phenoxyethyl acrylate (trade name: Light Acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.) were mixed. After that, zirconia beads (diameter: 0.03 mm) were added to the obtained mixture, and the mixture was subjected to dispersion treatment by shaking for 4 hours using a paint conditioner. Then, the zirconia beads were removed from the mixture with a polyester mesh filter to obtain a light-scattering particle dispersion.

<Preparation of Ink Composition of Example 4>
An ink composition of Example 4 was prepared in the same manner as in Example 3, except that the light-scattering particle dispersion C was used instead of the light-scattering particle dispersion B.

Comparative example 1
<Preparation of Light-scattering Particle Dispersion D>
In a container filled with argon gas, 8.0 g of titanium oxide (trade name: PF-690, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 210 nm) and a polymer dispersant (trade name: PB -821, manufactured by Ajinomoto Fine-Techno Co., Ltd.) and 11.8 g of phenoxyethyl acrylate (trade name: Light Acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.) were mixed. After that, zirconia beads (diameter: 0.03 mm) were added to the obtained mixture, and the mixture was subjected to dispersion treatment by shaking for 4 hours using a paint conditioner. Then, the zirconia beads were removed from the mixture with a polyester mesh filter to obtain a light-scattering particle dispersion.

<Preparation of Ink Composition of Comparative Example 1>
An ink composition of Comparative Example 1 was prepared in the same manner as in Example 1, except that the light-scattering particle dispersion D was used instead of the light-scattering particle dispersion A.

Comparative example 2
<Preparation of QD powder C by ligand exchange>
Nanosys InP nanocrystal dispersion (InP QD in Heptane Red InP QD, QD particles (luminescent nanocrystal particles) concentration 30%, organic ligand: oleic acid), 2.0 times the amount of PGMEA and QD Ligand exchange was carried out by adding organic ligand 1 in an amount corresponding to 20% by mass with respect to the amount of particles (excluding the amount of organic ligand) and stirring at 80° C. for 1 hour. By adding four times the amount of heptane to this solution, the QD particles were aggregated and precipitated by centrifugation, and then the QD particles were separated by decanting the supernatant. The resulting QD particles were dried in a vacuum dryer to obtain red-light-emitting QD powder C (QD particles/organic ligand=86% by mass/14% by mass).

<Preparation of Ink Composition of Comparative Example 2>
An ink composition of Comparative Example 1 was prepared in the same manner as in Example 1, except that QD powder C was used instead of QD powder A.

Comparative example 3
<Preparation of Light-scattering Particle Dispersion E>
In a container filled with argon gas, 8.0 g of titanium oxide (trade name: PF-690, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 210 nm) and a polymer dispersant (trade name: PB -821, manufactured by Ajinomoto Fine-Techno Co., Ltd.) and 10.6 g of phenoxyethyl acrylate (trade name: Light Acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.) were mixed. After that, zirconia beads (diameter: 0.03 mm) were added to the obtained mixture, and the mixture was subjected to dispersion treatment by shaking for 4 hours using a paint conditioner. Then, the zirconia beads were removed from the mixture with a polyester mesh filter to obtain a light-scattering particle dispersion.

<Preparation of Ink Composition of Comparative Example 3>
An ink composition of Comparative Example 3 was prepared in the same manner as in Example 1 except that the light-scattering particle dispersion E was used instead of the light-scattering particle dispersion A.

Comparative example 4
<Preparation of QD powder D by ligand exchange>
Nanosys InP nanocrystal dispersion (InP QD in Heptane Red InP QD, QD particles (luminescent nanocrystal particles) concentration 30%, organic ligand: oleic acid), 2.0 times the amount of PGMEA and QD Ligand exchange was carried out by adding organic ligand 1 in an amount corresponding to 60% by mass with respect to the amount of particles (excluding the amount of organic ligand) and stirring at 80° C. for 1 hour. By adding four times the amount of heptane to this solution, the QD particles were aggregated and precipitated by centrifugation, and then the QD particles were separated by decanting the supernatant. The obtained QD particles were dried in a vacuum dryer to obtain a red-light-emitting QD powder D (QD particles/organic ligand=48% by mass/52% by mass).

<Preparation of Ink Composition of Comparative Example 4>
An ink composition of Comparative Example 4 was prepared in the same manner as in Example 1, except that the luminescent nanocrystalline particle dispersion D was used instead of the luminescent nanocrystalline particle dispersion A.

Preparation of Samples for Evaluation The ink composition was applied to a glass substrate in the air by a spin coater so as to have a film thickness of 10 μm. Under a nitrogen atmosphere, the coating film is cured by irradiating UV with a UV irradiation device using an LED lamp with a dominant wavelength of 395 nm so that the integrated light amount becomes 10000 mJ / cm 2, and then placed in a glove box with an oxygen concentration of 1% by volume or less. The mixture was heated at 180° C. for 30 minutes to form a layer (light conversion layer) composed of a cured product of the ink composition on the glass substrate. Thus, an evaluation sample was obtained.

Evaluation of External Quantum Efficiency (EQE) A blue LED (peak emission wavelength: 450 nm) manufactured by CCS Corporation was used as a surface emitting light source. As a measurement device, an integrating sphere was connected to a radiation spectrophotometer (product name “MCPD-9800”) manufactured by Otsuka Electronics Co., Ltd., and the integrating sphere was placed above the blue LED. The produced evaluation sample was inserted between the blue LED and the integrating sphere, and the spectrum observed by lighting the blue LED and the illuminance at each wavelength were measured.
The external quantum efficiency was obtained as follows from the spectrum and illuminance measured by the above measuring device. The external quantum efficiency is a value indicating how much of the light (photons) incident on the light conversion layer is emitted to the observer side as fluorescence. Therefore, if this value is large, it indicates that the light conversion layer is excellent in light emission characteristics, which is an important evaluation index.
Red QD EQE (%) = [P1 (Red)]/E (Blue) x 100
Green QD EQE (%) = [P1 (Green) / E (Blue)] × 100
Here, E (Blue), P1 (Red) and P1 (Green) each represent the following.
E (Blue): Represents the total value of “illuminance×wavelength/hc” in the wavelength range of 380 to 490 nm.
P1 (Red): Represents the total value of “illuminance×wavelength/hc” in the wavelength range of 590 to 780 nm.
P1 (Green): 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 photons observed. In addition, h represents Planck's constant and c represents the speed of light.

EQE was evaluated according to the following criteria.
A: RedQD EQE≧35%, GreenQD EQE≧30%
B: Red QD 30% < EQE < 35%, Green QD 25% < EQE < 30%
C: Red QD EQE ≤ 30%, Green QD EQE ≤ 25%

Evaluation of redispersibility (filtration) If the redispersibility deteriorates due to aggregation of the luminescent nanocrystalline particles and the light-scattering particles, the dischargeability as an inkjet ink may deteriorate. Therefore, in order to evaluate the redispersibility of the particles, the filterability of the ink composition was evaluated. Agglomerates reduce the filterability, so the better the filterability, the better the redispersibility. After stirring 5 ml of the ink composition stored in a 40° C. constant temperature bath for 2 weeks with a vortex mixer, it was filtered at a pressure of 0.1 MPa using a polypropylene filter φ25 mm with a pore size of 1.2 μm (manufactured by Nippon Pall Co., Ltd.). "A" was given to those that were filtered, "B" was given to those whose entire amount was filtered in 10 minutes, and "C" was given to those whose entire amount could not be filtered.

Evaluation of Leakage Light A blue LED (peak emission wavelength: 450 nm) manufactured by CCS Corporation was used as a surface emitting light source. An evaluation sample was placed on the light source with the glass substrate side facing downward. The integrating sphere was connected to a radiation spectrophotometer (trade name: “MCPD-9800”) manufactured by Otsuka Electronics Co., Ltd., and brought close to the light conversion filter placed on the blue LED. In this state, the blue LED was turned on, and the observed peak intensity (S) of light with a wavelength of 450 nm was measured. Next, light with a wavelength of 450 nm was observed in the same manner as described above, except that the glass substrate (slide glass) used for making the light conversion filter was placed above the light source instead of the light conversion filter. was measured. The leakage rate T (peak intensity ratio: S/R×100) of light with a wavelength of 450 nm was calculated and evaluated according to the following criteria. The smaller the light leakage rate, the higher the color purity, which is preferable.
A: Red QD T ≤ 10%, Green QD T ≤ 20%
C: Red QD T>10%, Green QD T>20%

Tables 2 and 3 show the evaluation results. The amount of organic ligand relative to the luminescent nanocrystalline particles in the table means the content of the organic ligand relative to 100 parts by mass of the luminescent nanocrystalline particles in the ink composition. The amount of the dispersant relative to the light-scattering particles in the table means the content of the polymer dispersant with respect to 100 parts by mass of the light-scattering particles in the ink composition.

It was shown that the ink compositions of Examples can improve the external quantum efficiency of the coating film and have excellent redispersibility (comparison with Comparative Examples). It was also confirmed that the ink compositions of Examples further have the effect of suppressing leaked light.

DESCRIPTION OF SYMBOLS 10... Pixel part 10a... 1st pixel part 10b... 2nd pixel part 10c... 3rd pixel part 11a... 1st luminescent nanocrystal particle 11b... 2nd luminescent nanocrystal particle , 12a... First light-scattering particles, 12b... Second light-scattering particles, 12c... Third light-scattering particles, 20... Light shielding part, 30... Light conversion layer, 40... Base material, 100... Color filter.

Claims

containing luminescent nanocrystalline particles, an organic ligand capable of binding to the surface of the luminescent nanocrystalline particles, light-scattering particles, a polymer dispersant, and a photopolymerizable compound;
The content of the organic ligand is 15 to 50 parts by mass with respect to 100 parts by mass of the luminescent nanocrystalline particles,
An inkjet ink composition for a color filter, wherein the content of the polymer dispersant is 3 to 15 parts by mass with respect to 100 parts by mass of the light-scattering particles.
The inkjet ink composition for color filters according to claim 1, wherein the organic ligand has a molecular weight of 1000 or less.
The inkjet ink composition for color filters according to claim 1 or 2, wherein the polymer dispersant has a weight average molecular weight of 1000 or more.
The inkjet ink composition for color filters according to any one of claims 1 to 3, wherein the polymer dispersant has both an acid value and an amine value.
The inkjet ink composition for color filters according to any one of claims 1 to 3, wherein the polymer dispersant contains two or more types of polymer dispersants.
The inkjet ink composition for a color filter according to any one of claims 1 to 5, wherein the light-scattering particles have an average particle size of 0.15 µm or more and 0.5 µm or less.
A cured product of the inkjet ink composition for color filters according to any one of claims 1 to 6.
comprising a plurality of pixel portions and a light shielding portion provided between the plurality of pixel portions;
A light conversion layer, wherein the plurality of pixel portions have luminescent pixel portions containing a cured product of the inkjet ink composition for a color filter according to any one of claims 1 to 6.
As the luminescent pixel portion,
a first luminescent pixel portion containing luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with an emission peak wavelength in the range of 605 to 665 nm;
a second luminescent pixel portion containing luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with an emission peak wavelength in the range of 500 to 560 nm;
9. The light conversion layer of claim 8, comprising:
A color filter comprising the light conversion layer according to claim 8 or 9.