JP7243073B2 - Ink composition and cured product thereof, light conversion layer, and color filter - Google Patents

Description

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

Conventionally, a pixel part (color filter pixel part) in a display such as a liquid crystal display device is, for example, a curable resist containing red organic pigment particles or green organic pigment particles, an alkali-soluble resin and / or an acrylic monomer. It has been manufactured by photolithographic methods using materials.

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 a disadvantage 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, the formation of the pixel portion of the light conversion substrate by the inkjet method has begun to be studied (Patent Document 1).

WO2008/001693

In the pixel portion (e.g., color filter pixel portion) formed by an ink composition containing luminescent nanocrystalline particles, the initial external quantum efficiency (EQE) is maintained for a long period of time from the viewpoint of low power consumption. required to be maintained.

Accordingly, the present invention provides an ink composition capable of forming a pixel portion having excellent external quantum efficiency maintenance performance, a cured product of the ink composition, and a light conversion layer and a color filter using the ink composition. for the purpose.

One aspect of the present invention comprises luminescent nanocrystalline particles, and a photopolymerizable compound comprising an allyl ether group and an ethylenically unsaturated group capable of reacting with the allyl ether group to form an intramolecular ring. It is related with the ink composition which carries out.

According to the ink composition of the present invention, it is possible to form a pixel portion having excellent external quantum efficiency maintenance performance.

［式（ＩＩ）中、＊は結合手を示す。］ The photopolymerizable compound may contain a structure represented by the following formula (II) as the structure having the ethylenically unsaturated group.

[In Formula (II), * indicates a bond. ]

The ink composition may further contain a monofunctional or polyfunctional (meth)acrylate.

The content of the luminescent nanocrystalline particles may be greater than 20% by weight based on the weight of the non-volatile matter of the ink composition.

The ink composition may further contain a thiol compound.

The ink composition may further contain an antioxidant.

The ink composition may further contain light scattering particles.

The content of the inorganic component in the ink composition may be 30% by mass or more based on the mass of the nonvolatile matter in the ink composition.

The ink composition can be used to form a light conversion layer. That is, the ink composition of the present invention may be an ink composition for forming a light conversion layer.

The ink composition may be an ink composition (inkjet ink) used in an inkjet system. As described above, the ink composition of the present invention tends to be excellent in ejection stability, and thus can be suitably used as an inkjet ink.

One aspect of the present invention relates to a cured product of an ink composition containing luminescent nanocrystalline particles and a polymer containing a structural unit having an ether ring.

According to the cured product of the ink composition of the present invention, it is possible to obtain a pixel portion having excellent external quantum efficiency maintenance performance.

One aspect of the present invention includes a plurality of pixel portions and light shielding portions provided between the plurality of pixel portions, wherein the plurality of pixel portions is a luminescent pixel portion containing a cured product of the ink composition described above. It relates to a light conversion layer having

The light conversion layer contains, as the luminescent pixel portion, 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. 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. , may be provided.

The light conversion layer may further comprise a non-luminescent pixel portion containing light scattering particles.

One aspect of the present invention relates to a color filter comprising the light conversion layer described above.

According to the present invention, there are provided an ink composition capable of forming a pixel portion having excellent external quantum efficiency maintenance performance, a cured product of the ink composition, and a light conversion layer and a color filter using the ink composition. be able to.

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

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.

<Ink composition>
An ink composition of one embodiment comprises luminescent nanocrystalline particles, a photopolymerizable compound containing an allyl ether group and an ethylenically unsaturated group capable of reacting with the allyl ether group to form an intramolecular ring, A luminescent ink composition containing Since the ink composition of one embodiment has such a configuration, it can maintain the external quantum efficiency for a long period of time. That is, the ink composition of one embodiment is excellent in maintaining the external quantum efficiency. Although the reason why such an effect is obtained is not clear, the present inventors speculate as follows.

Since the ink composition of the present embodiment contains the specific photopolymerizable compound, the curing reaction of the ink composition of the present embodiment is such that the photopolymerizable compound forms an intramolecular ring (ether ring) through an intramolecular reaction. It progresses by polymerizing while Therefore, the pixel portion formed by the ink composition of the present embodiment (the pixel portion containing the cured product of the ink composition of the present embodiment) contains a polymer containing a structural unit having an ether ring as a curing component. It will happen. In the present embodiment, it is presumed that the maintenance rate of the external quantum efficiency of the pixel portion is improved because the intramolecular motion of the curing component is controlled by the ether ring.

Further, when a polymer containing a structural unit having an ether ring is introduced into a pixel portion using a conventional ink composition, the ink composition must contain a polymer containing a structural unit having an ether ring. Coalescence increases the viscosity of the ink composition. On the other hand, in the ink composition of the present embodiment, the photopolymerizable compound becomes a polymer after the pixel portion is formed, so there is no need to include a polymer in the ink composition. Therefore, in this embodiment, an ink composition with a lower viscosity can be obtained. In addition, when a conventional ink composition is used for forming a pixel portion by an inkjet method, nozzle clogging or the like occurs due to an increase in the viscosity of the ink composition, and sufficient ejection stability cannot be obtained. may not be On the other hand, in the ink composition of the present embodiment, since the photopolymerizable compound becomes a polymer after forming the pixel portion, the polymer is introduced into the pixel portion while suppressing an increase in the viscosity of the ink composition. can do. Therefore, it is possible to achieve both ejection stability and external quantum efficiency maintenance performance.

The ink composition of one embodiment is used for forming a light conversion layer (for example, for a color filter), which is used to form a pixel part of a light conversion layer of a color filter or the like by a method such as a photolithography method or an inkjet method. ) is an ink composition.

The ink composition of one embodiment can be applied as an ink used in a known and commonly used method for manufacturing a color filter, without wasting relatively expensive materials such as luminescent nanocrystalline particles and solvents. Since the pixel portion (light conversion layer) can be formed only by using the required amount at the required location, it is preferable to prepare and use it appropriately for the inkjet method rather than for the photolithographic method.

When a pixel portion containing luminescent nanocrystalline particles is formed by an inkjet method using a conventional ink composition, it is difficult to achieve both excellent ejection stability and excellent external quantum efficiency maintenance performance. However, according to the ink composition of one embodiment, it is possible to achieve both excellent ejection stability and excellent ability to maintain external quantum efficiency even in an inkjet method. That is, the ink composition of one embodiment is suitably used for forming color filter pixel portions by an inkjet method.

In the following, an ink composition for a color filter (inkjet ink for a color filter) used in an inkjet method, which contains luminescent nanocrystalline particles, a photopolymerizable compound, a photopolymerization initiator and light scattering particles, is taken as an example. explain.

[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.

Luminescent nanocrystalline particles can, for example, emit light (fluorescence or phosphorescence) at a wavelength different from the absorbed wavelength by absorbing light of a given wavelength. The luminescent nanocrystalline particles may be red luminescent nanocrystalline particles (red luminescent nanocrystalline particles) that emit light having an emission peak wavelength in the range of 605-665 nm (red light), Green luminescent nanocrystalline particles (green luminescent nanocrystalline particles) that emit light with an emission peak wavelength in the range of 420-480 nm (blue light). ), may be blue-emitting nanocrystalline particles (blue-emitting nanocrystalline particles). 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 (blue light) with a wavelength in the range of 400 nm or more and less than 500 nm (especially light with a wavelength in the range of 420 to 480 nm), 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 may be luminescent nanocrystalline particles comprising semiconductor materials (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 may be 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 may be a structure consisting of a core, a first shell and a second shell (core/shell/shell structure). Each of the core and shell may 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 to be 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. The shape of the luminescent nanocrystalline particles may be, for example, spherical, ellipsoidal, pyramidal, disk-like, branch-like, net-like, rod-like, and the 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 may be 1 nm or more, or 1.5 nm, from the viewpoints of easily obtaining light emission of a desired wavelength and from the viewpoint of excellent dispersibility and storage stability. or more, or 2 nm or more. From the viewpoint of easily obtaining a desired emission wavelength, it may be 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.

From the viewpoint of dispersion stability, the luminescent nanocrystalline particles preferably have organic ligands on their surfaces. Organic ligands may be coordinated to the surface of the luminescent nanocrystalline particles, for example. In other words, the surface of the luminescent nanocrystalline particles may be passivated by organic ligands. Moreover, when the ink composition further contains a polymer dispersant, which will be described later, the luminescent nanocrystalline particles may have the polymer dispersant on their surfaces. In this embodiment, for example, the organic ligand is removed from the luminescent nanocrystalline particles having the above-described organic ligand, and the organic ligand is exchanged with the polymeric dispersant, thereby dispersing the polymeric dispersant on the surface of the luminescent nanocrystalline particles. may be combined. However, from the viewpoint of dispersion stability when used as an inkjet ink, it is preferable that a polymer dispersant is added to the luminescent nanocrystalline particles with the organic ligands still coordinated.

As the organic ligand, a functional group for ensuring affinity with a photopolymerizable compound, an organic solvent, etc. (hereinafter also simply referred to as "affinity group"), and a functional group capable of binding to the luminescent nanocrystalline particles. (functional group for ensuring adsorption to luminescent nanocrystalline particles). The affinity group may be 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 bind to luminescent nanocrystalline particles include, for example, hydroxyl groups, amino groups, carboxyl groups, thiol groups, phosphate groups, phosphonic acid groups, phosphine groups, phosphine oxide groups, and alkoxysilyl groups. Examples of organic ligands include TOP (trioctylphosphine), TOPO (trioctylphosphine oxide), oleic acid, oleylamine, octylamine, trioctylamine, hexadecylamine, octanethiol, dodecanethiol, and hexylphosphonic acid (HPA). , tetradecylphosphonic acid (TDPA), and octylphosphinic acid (OPA).

The organic ligand preferably has a main chain containing a polyoxyalkylene group and one or more functional groups capable of binding to the luminescent nanocrystalline particles at at least one end of the main chain. The polyoxyalkylene group contained in the main chain includes, for example, a polyoxyethylene group and a polyoxypropylene group. The main chain has, for example, a substituted or unsubstituted hydrocarbon group in addition to the polyoxyalkylene group. A functional group is, for example, a group capable of coordinating to a luminescent nanocrystalline particle. Functional groups may include, for example, functional groups capable of bonding with the luminescent nanocrystalline particles described above. Here, the term "main chain" refers to the longest molecular chain constituting the compound. The substituted or unsubstituted hydrocarbon group may have, for example, 1-10 carbon atoms. In the substituted hydrocarbon group, part of the carbon atoms may be substituted with a heteroatom such as a sulfur atom or a nitrogen atom, a carbonyl group, or the like.

The organic ligand has one or more first functional groups capable of binding to the luminescent nanocrystalline particles at one end of the main chain, and a second functional group different from the first functional group at the other end of the main chain. may have a group. The first functional group may be the same as those described above as functional groups capable of binding to the luminescent nanocrystalline particles. The number of first functional groups may be one or more, two or more, or two. The second functional group may be the same as the functional group described above as the functional group capable of binding to the luminescent nanocrystalline particles, or may be another group different from the functional group. Other groups may be, for example, cycloalkyl groups, aryl groups. The number of second functional groups may be one or more, and may be one.

［式（１－１）中、ｐは０～５０の整数を示し、ｑは０～５０の整数を示す。］ In one embodiment, the organic ligand may be an organic ligand represented by formula (1-1) below.

[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.

In one embodiment, the first functional group is a carboxyl group and the second functional group is a hydroxyl group, and the organic ligand may have two or more first functional groups. That is, in one embodiment, the organic ligand may have one or more carboxyl groups at one end of the main chain and a hydroxyl group at the other end of the main chain. It has two or more groups and may have a hydroxyl group at the other end of the main chain.

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

In formula (1-2), A ¹ represents a monovalent group containing a carboxyl group, A ² represents a monovalent group containing a hydroxyl 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 may be 2 or more, 2 or more and 4 or less, or 2. The number of carbon atoms in the alkylene group represented by L may be, for example, 1-10. In the alkylene group represented by L, some of the carbon atoms may be substituted with hetero atoms, and at least one hetero atom selected from the group consisting of oxygen atoms, sulfur atoms and nitrogen atoms. good too. r may be, for example, an integer of 1-100, or an integer of 10-20.

The organic ligand is preferably an organic ligand represented by formula (1-2A) below.

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

The organic ligand is preferably an organic ligand represented by formula (1-2A) from the viewpoint of excellent external quantum efficiency and maintenance factor of the pixel portion.

As the luminescent nanocrystalline particles, those dispersed in a colloidal form in an organic solvent, a photopolymerizable compound, or the like can be used. The surfaces of the luminescent nanocrystalline particles dispersed in the organic solvent are preferably passivated with the above-described organic ligands. Examples of organic solvents include cyclohexane, hexane, heptane, chloroform, toluene, octane, chlorobenzene, tetralin, diphenyl ether, propylene glycol monomethyl ether acetate, butyl carbitol acetate, 1,4-butanediol diacetate, and mixtures thereof. mentioned.

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 more than 20% by mass, more preferably 23% by mass, based on the mass of the non-volatile matter of the ink composition, from the viewpoint of improving the maintenance rate of the external quantum efficiency. % or more, more preferably 25 mass % or more. When the content of the luminescent nanocrystalline particles is more than 20% by mass, excellent emission intensity can be obtained, and such an ink composition is suitably used for color filters. From a similar point of view, the content of the luminescent nanocrystalline particles may be 50% by mass or less, 40% by mass or less, or 35% by mass or less based on the mass of the nonvolatile matter in the ink composition. or 30% by mass or less. The content of the luminescent nanocrystalline particles is 50% by mass or less based on the mass of the non-volatile matter in the ink composition from the viewpoint of better ejection stability. Moreover, when the content of the luminescent nanocrystalline particles is 50% by mass or less, excellent emission intensity can be obtained, and such an ink composition is suitably used as an inkjet ink for color filters. From the same point of view, the content of the luminescent nanocrystalline particles may be 40% by mass or less, 35% by mass or less, or 30% by mass, based on the mass of the nonvolatile matter of the ink composition. It may be below. The content of the luminescent nanocrystalline particles is, for example, more than 20% by mass and 50% by mass or less, 23 to 50% by mass, 25 to 50% by mass, more than 20% by mass, and 40% by mass, based on the mass of the nonvolatile matter of the ink composition. % by mass or less, more than 20% by mass and less than 35% by mass, or more than 20% by mass and less than 30% by mass. As used herein, the term "mass of non-volatile matter in the ink composition" refers to the total mass of the ink composition minus the mass of the solvent when the ink composition contains a solvent. When no solvent is included, it refers to the total weight of the ink composition.

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.

[Photopolymerizable compound]
The ink composition of the present embodiment includes an allyl ether group (—O—CH ₂ —CH ₂ ═CH ₂ ) as a photopolymerizable compound, and an ethylenic compound capable of forming an intramolecular ring by reacting with the allyl ether group. and a photopolymerizable compound (hereinafter also referred to as "first photopolymerizable compound") containing an unsaturated group. As used herein, an ethylenically unsaturated group means a group having an ethylenically unsaturated bond (polymerizable carbon-carbon double bond).

Here, "photopolymerizable compound" means a compound that polymerizes by irradiation with light (active energy ray). A photopolymerizable compound is typically used together with a photopolymerization initiator, which will be described later. For example, a photoradical polymerizable compound is used together with a photoradical polymerization initiator. In other words, the ink composition of the present embodiment may contain a photopolymerizable component including a photopolymerizable compound (for example, a photoradical polymerizable compound) and a photopolymerization initiator (for example, a photoradical polymerization initiator).

The intramolecular cyclization reaction between the allyl ether group and the ethylenically unsaturated group in the first photopolymerizable compound may be an intramolecular radical cyclization reaction. In the intramolecular radical cyclization reaction, the ethylenically unsaturated group and the allyl ether group undergo a radical reaction to form a carbon-carbon bond between the ethylenically unsaturated bonds, thereby forming an intramolecular ring ( ether ring) is formed. Therefore, by subjecting the first photopolymerizable compound to radical polymerization, the intramolecular cyclization reaction and the polymerization reaction proceed substantially simultaneously, yielding a polymer having a structural unit containing an ether ring.

The structure of the intramolecular ring formed may be, for example, a 4-membered ring structure (eg, tetrahydrofuran structure), a 5-membered ring structure, or a 6-membered ring structure, preferably a 5-membered ring structure. The positional relationship between the allyl ether group and the ethylenically unsaturated group that reacts with the allyl ether group in the first photopolymerizable compound may be any positional relationship capable of forming such an intramolecular ring.

［式（Ｉ）中、Ｘは水素原子又は一価の有機基を示し、Ｙは二価の炭化水素基を示す。Ａで示す点線で囲われた部分はアリルエーテル基中のエチレン性不飽和結合を示し、Ｂで示す点線で囲われた部分は当該アリルエーテル基と反応して分子内環を形成しうるエチレン性不飽和基中のエチレン性不飽和結合を示す。］ The allyl ether group and the ethylenically unsaturated group capable of reacting with the allyl ether group to form an intramolecular ring may be linked by a divalent hydrocarbon group. That is, the first photopolymerizable compound may be a compound represented by formula (I) below.

[In Formula (I), X represents a hydrogen atom or a monovalent organic group, and Y represents a divalent hydrocarbon group. The portion surrounded by a dotted line indicated by A indicates an ethylenically unsaturated bond in the allyl ether group, and the portion surrounded by a dotted line indicated by B is an ethylenic bond capable of forming an intramolecular ring by reacting with the allyl ether group. Indicates an ethylenically unsaturated bond in an unsaturated group. ]

The divalent hydrocarbon group Y is, for example, an alkylene group, preferably a methylene group.

［式（ＩＩ）中、＊は結合手を示す。］ The ethylenically unsaturated group capable of forming an intramolecular ring by reacting with an allyl ether group may be, for example, an ethylenically unsaturated group contained in the structure represented by formula (II) below. That is, the first photopolymerizable compound may contain a structure represented by the following formula (II) as a structure having an ethylenically unsaturated group capable of forming an intramolecular ring by reacting with an allyl ether group. .

[In Formula (II), * indicates a bond. ]

［式（ＩＩａ）中、＊は結合手を示し、Ｒ^１は炭化水素基を示す。］

［式（ＩＩＩ）中、＊は結合手を示し、Ｒ^１は炭化水素基を示す。］ The structure represented by formula (II) is preferably a structure represented by formula (IIa) below. That is, X in formula (I) is preferably a group represented by formula (III) below.

[In Formula (IIa), * indicates a bond, and R ¹ indicates a hydrocarbon group. ]

[In Formula (III), * indicates a bond, and R ¹ indicates a hydrocarbon group. ]

The number of carbon atoms in R ¹ (the number of carbon atoms in the hydrocarbon group) is not particularly limited, and is, for example, 1-4. R ¹ may be a substituted or unsubstituted aliphatic hydrocarbon group. R ¹ is preferably an alkyl group, more preferably a methyl group.

［式（Ｉａ）中、Ｒ^２はアルキル基を示す。］ The first photopolymerizable compound is preferably alkyl 2-allyloxymethyl acrylate from the viewpoint of obtaining better ejection stability and better performance of maintaining external quantum efficiency. That is, the first photopolymerizable compound is preferably a compound represented by formula (Ia) below.

[In Formula (Ia), R ² represents an alkyl group. ]

R ² in formula (Ia) is preferably a methyl group. That is, the first photopolymerizable compound is more preferably methyl 2-allyloxymethyl acrylate.

The number of ethylenically unsaturated bonds (the number of ethylenically unsaturated groups) of the first photopolymerizable compound is preferably 2 from the viewpoint of suppressing the progress of side reactions during the intramolecular cyclization reaction. That is, X and Y in formula (I) preferably do not contain ethylenically unsaturated bonds.

The molecular weight of the first photopolymerizable compound is preferably 300 or less, more preferably 250 or less, still more preferably 200 or less, from the viewpoint of excellent ejection stability of the ink composition. The molecular weight of the first photopolymerizable compound may be 150 or greater, 200 or greater, or 250 or greater.

The viscosity of the first photopolymerizable compound is preferably 20 mPa·s or less, more preferably 12 mPa·s or less, from the viewpoint of excellent ejection stability of the ink composition. The viscosity of the first photopolymerizable compound may be 1.5 mPa·s or more, 2.9 mPa·s or more, or 5.3 mPa·s or more.

Conventionally, from the viewpoint of improving ejection stability required for inkjet inks, low-viscosity photopolymerizable compounds such as (meth)acrylates have been studied as photopolymerizable compounds for inkjet inks. However, with these photopolymerizable compounds, it has been difficult to achieve both excellent ejection stability and excellent optical properties (external quantum efficiency, ability to maintain external quantum efficiency, etc.). On the other hand, the first photopolymerizable compound tends to have a low viscosity before polymerization (before curing), and after polymerization (after curing), the conventional photopolymerizable compound polymer can take a strong molecular structure compared to Therefore, by using the first photopolymerizable compound, there is a tendency to easily achieve both excellent ejection stability and excellent optical properties (external quantum efficiency, ability to maintain external quantum efficiency, etc.). .

The content of the first photopolymerizable compound is selected from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink, the viewpoint of being excellent in maintaining the external quantum efficiency of the pixel portion (cured product of the ink composition), and the pixel portion ( From the viewpoint of improving the solvent resistance and abrasion resistance of the cured product of the ink composition, 5% by mass or more, 10% by mass or more, 15% by mass or more, and 20% by mass based on the mass of the nonvolatile matter of the ink composition Above, it may be 25% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more. The content of the first photopolymerizable compound is determined from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink, and from the viewpoint of better performance in maintaining the external quantum efficiency of the pixel portion (cured product of the ink composition). It may be 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less based on the mass of the non-volatile matter of the product. The content of the first photopolymerizable compound is, for example, 5 to 70% by mass, 10 to 70% by mass, 15 to 70% by mass, 25 to 70% by mass, based on the mass of the nonvolatile matter of the ink composition. It may be 30-60% by weight, 35-60% by weight, 35-50% by weight or 40-50% by weight.

A 1st photopolymerizable compound may be used individually by 1 type, and may use 2 or more types together. Moreover, the ink composition may contain, as a photopolymerizable compound, a second photopolymerizable compound different from the first photopolymerizable compound. The second photopolymerizable compound contained in the ink composition may be one or more.

Examples of the second photopolymerizable compound include monomers having an ethylenically unsaturated group. Here, the ethylenically unsaturated monomer means a monomer having an ethylenically unsaturated bond (carbon-carbon double bond). Examples of monomers having an ethylenically unsaturated group include monomers having an ethylenically unsaturated group such as a vinyl group, vinylene group, vinylidene group, and (meth)acryloyl group. A monofunctional or bifunctional (meth)acrylate is more preferred from the viewpoint of further improving the external quantum efficiency, and a monofunctional or bifunctional acrylate is more preferable from the viewpoint of further improving the performance of maintaining the external quantum efficiency. 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”. Further, monofunctional (meth) acrylate means a (meth) acrylate monomer having one (meth) acryloyl group, and polyfunctional (meth) acrylate has two or more (meth) acryloyl groups. It means (meth)acrylate monomer.

The number of ethylenically unsaturated bonds (eg, the number of ethylenically unsaturated groups) in the ethylenically unsaturated monomer is, for example, 1-3. From the viewpoint of obtaining better ejection stability and the viewpoint of obtaining better external quantum efficiency maintenance performance, a polyfunctional unsaturated monomer having two or more ethylenically unsaturated bonds is preferable, and two or more ( A polyfunctional (meth)acrylate having a meth)acryloyl group is more preferred, and a polyfunctional acrylate having two or more acryloyl groups is even more preferred. As polyfunctional (meth)acrylates, bifunctional (meth)acrylates such as alkylene glycol di(meth)acrylates and polyalkylene glycol di(meth)acrylates are preferred, and bifunctional acrylates are more preferred.

Specific examples of polyfunctional (meth)acrylates include 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 3- methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9 - 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 ) acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol hydroxypivalic acid ester diacrylate, tris(2-hydroxyethyl) isocyanurate with two hydroxyl groups Di(meth)acrylate substituted by (meth)acryloyloxy group, two hydroxyl groups of diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol are (meth)acryloyloxy groups a di(meth)acrylate substituted with a di(meth)acrylate in which two hydroxyl groups of a diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A are substituted with (meth)acryloyloxy groups , a di(meth)acrylate obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane, in which two hydroxyl groups of the triol are substituted with (meth)acryloyloxy groups, and 4 per 1 mol of bisphenol A Bifunctional (meth)acrylates such as di(meth)acrylate in which two hydroxyl groups of a diol obtained by adding ethylene oxide or propylene oxide in a molar amount or more are substituted by (meth)acryloyloxy groups, glycerin tri(meth) Examples include trifunctional (meth)acrylates such as acrylates and trimethylolethane tri(meth)acrylates. Among these, alkylene glycol di(meth)acrylates having 4 to 12 carbon atoms in the alkylene group are preferred, and examples include 1,4-butanediol di(meth)acrylate and 1,6-hexanediol di(meth)acrylate. It is preferably used.

The second photopolymerizable compound may be a monofunctional (meth)acrylate. Monofunctional (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxy ethyl (meth) acrylate, nonylphenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, isobornyl (meth) acrylate, di Cyclopentanyl (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, mono(2-acryloyloxyethyl) succinate, N-[2-(acryloyloxy)ethyl]phthalimide, N-[2-( acryloyloxy)ethyl]tetrahydrophthalimide and the like.

The content of the second photopolymerizable compound is selected from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink, the viewpoint of being excellent in maintaining the external quantum efficiency of the pixel portion (cured product of the ink composition), and the pixel portion ( From the viewpoint of improving the solvent resistance and abrasion resistance of the cured product of the ink composition), the non-volatile content of the ink composition is 5% by mass or more, 10% by mass or more, or 15% by mass or more. good. The content of the second photopolymerizable compound is determined from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink, and from the viewpoint of better maintenance performance of the external quantum efficiency of the pixel portion (cured product of the ink composition). It may be 30% by mass or less, 20% by mass or less, or 25% by mass or less based on the mass of the nonvolatile matter of the product.

The ratio of the content of the second photopolymerizable compound to the content of the first photopolymerizable compound (content of the second photopolymerizable compound/content of the first photopolymerizable compound) is From the viewpoint of better maintenance performance of the external quantum efficiency of (the cured product of the ink composition), it may be, for example, 0.3 or more, 0.4 or more, or 0.5 or more, and 0.8 or less and 0.7 or less. Or it may be 0.6 or less.

The content of all photopolymerizable compounds contained in the ink composition (the total amount of the first photopolymerizable compound and the second photopolymerizable compound) is From the viewpoint of better quantum efficiency maintenance performance, for example, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or 45% by mass or more, and may be 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less.

The photopolymerizable compound used in this embodiment may be 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 photopolymerizable compound described above may be used as a mixture with a polymerization inhibitor. Polymerization inhibitors include 4-hydroxy-2,2,6,6-tetramethylpiperidinooxy, free radicals and the like. The amount of the polymerization inhibitor used may be an amount that does not inhibit the polymerization of the photopolymerizable compound during the formation of the pixel portion. part by mass.

[Photoinitiator]
A photoinitiator is a photoradical polymerization initiator, for example. 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.

Hydrogen abstraction photoradical polymerization initiators include benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4'-methyl-diphenylsulfide and the like. A molecular cleavage type radical photopolymerization initiator and a hydrogen abstraction type photoradical polymerization initiator may be used in combination.

In the present embodiment, the ink composition may contain a photopolymerization initiator having a molecular weight of 350 or less from the viewpoint of obtaining excellent external quantum efficiency. In particular, when the content of the luminescent nanocrystalline particles is more than 20% by mass and 50% by mass or less based on the mass of the nonvolatile matter of the ink composition, the ink composition has a molecular weight of 350 or less. It preferably contains an agent.

The molecular weight of the photopolymerization initiator is preferably 330 or less from the standpoint of achieving a superior effect of improving the external quantum efficiency and from the standpoint of easily achieving both ejection stability and curability. The molecular weight of the photopolymerization initiator is preferably 150 or more, more preferably 200 or more, and still more preferably 250, from the viewpoint of improving the effect of improving the external quantum efficiency and easily achieving both ejection stability and curability. 300 or more, particularly preferably 300 or more. From these points of view, the molecular weight of the photoinitiator may be 150-350, 200-350, 250-350, 300-350, 150-330, 200-330, 250-330 or 300-330. Although the ink composition may contain a photopolymerization initiator having a molecular weight of more than 350, the content of the photopolymerization initiator having a molecular weight of 350 or less in the total amount of the photopolymerization initiator is preferably 1% by mass. or more, more preferably 2% by mass or more. The content of the photopolymerization initiator having a molecular weight of 350 or less in the total amount of the photopolymerization initiator may be 50% by mass or more, 70% by mass or more, or 90% by mass or more. The content of the photopolymerization initiator having a molecular weight of 350 or less may be 100% by mass.

From the viewpoint of curability of the ink composition, the content of the photopolymerization initiator may be 0.1 parts by mass or more, or 0.5 parts by mass or more with respect to 100 parts by mass of the photopolymerizable compound. It may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more. The content of the photopolymerization initiator may be 40 parts by mass or less, or 30 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). or less, 20 parts by mass or less, or 10 parts by mass or less.

[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.

At least part of the surface of the light-scattering particles may be covered with alumina. For example, 50 area % or more of the surface of the light-scattering particles may be covered with alumina, or the entire surface of the light-scattering particles may be covered with alumina. In this case, the light-scattering particles can also be referred to as light-scattering particles surface-treated with alumina.

As a method of covering at least part of the surface of the light-scattering particles with alumina (surface-treating with alumina), for example, a wet treatment method (adding an aluminum salt aqueous solution to the light-scattering particle slurry and neutralizing the solution method of adsorbing on the surface of the light-scattering particles). Examples of light-scattering particles include "MPT-141", "CR-50", "CR-50-2", "CR-58", "CR-58-2", and "CR" manufactured by Ishihara Sangyo Co., Ltd. -60", "CR-60-2", "JR405", "JR603", "JR605", "JR701", and "JR806" manufactured by Tayca Corporation. The surface of the light-scattering particles may be coated with alumina and other ingredients such as silica, zinc oxide, titanium oxide, zirconium oxide, and organic substances such as stearic acid and polysiloxane.

The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition may be 0.05 μm (50 nm) or more from the viewpoint of excellent ejection stability and an excellent effect of improving the external quantum efficiency. , 0.2 μm (200 nm) or more, or 0.3 μm (300 nm) or more. The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition may be 1.0 μm (1000 nm) or less, or 0.6 μm (600 nm) or less, from the viewpoint of excellent ejection stability. It may be 0.4 μm (400 nm) or less. The average particle diameter (volume average diameter) of the light scattering particles in the ink composition is 0.05 to 1.0 μm, 0.05 to 0.6 μm, 0.05 to 0.4 μm, 0.2 to 1 0.0 μm, 0.2-0.6 μm, 0.2-0.4 μm, 0.3-1.0 μm, 0.3-0.6 μm, or 0.3-0.4 μm. From the viewpoint of easily obtaining such an average particle diameter (volume average diameter), the average particle diameter (volume average diameter) of the light-scattering particles used may be 0.05 μm or more and 1.0 μm or less. may 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 average particle size (volume average size) of the light-scattering particles to be used can be obtained by measuring the particle size of each particle with, for example, a transmission electron microscope or scanning electron microscope and calculating the volume average size.

The content of the light-scattering particles in the ink composition may be 0.1% by mass or more, or 1% by mass, based on the mass of the nonvolatile matter in the ink composition, from the viewpoint of improving the external quantum efficiency. 5% by mass or more, 7% by mass or more, 10% by mass or more, or 12% by mass or more. The content of the light-scattering particles may be 60% by mass or less, preferably 50% by mass, based on the mass of the nonvolatile matter in the ink composition, from the viewpoint of excellent ejection stability and an excellent effect of improving the external quantum efficiency. % or less, 40% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, or 15% by mass % or less. 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 mass ratio of the content of the light-scattering particles to the content of the luminescent nanocrystalline particles (light-scattering particles/luminescent nanocrystalline particles) is 0.1 or more from the viewpoint of improving the external quantum efficiency. may be 0.2 or more, or 0.5 or more. The mass ratio (light-scattering particles/luminescent nanocrystalline particles) may be 5.0 or less from the viewpoint of excellent external quantum efficiency improvement effect and excellent continuous ejection properties (ejection stability) during inkjet printing. , may be 2.0 or less, or may be 1.5 or less.

The content of the inorganic component in the ink composition (for example, the total amount of the luminescent nanocrystalline particles and the light-scattering particles) is less than the mass of the non-volatile matter in the ink composition from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink. As a standard, it is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 45% by mass or more. The content of the inorganic component in the ink composition (for example, the total amount of the luminescent nanocrystalline particles and the light-scattering particles) is less than the mass of the non-volatile matter in the ink composition from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink. As a standard, it is preferably 70% by mass or less, more preferably 65% by mass or less, and even more preferably 60% by mass or less. The content of inorganic components (for example, the total amount of luminescent nanocrystalline particles and light-scattering particles) in the ink composition may be 30 to 70% by weight, 40 to 65% by weight, or 45 to 60% by weight. .

The ink composition may further contain components other than the components described above as long as the effects of the present invention are not impaired. Other components include, for example, polymer dispersants, solvents, antioxidants, thiol compounds, and the like.

[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. The polymer dispersant is preferably bound to the surface of the light-scattering particles and adsorbed to the light-scattering particles. may be free in the ink composition.

By the way, aggregation of luminescent nanocrystalline particles and light-scattering particles is considered to be one of the causes of deterioration in ejection stability in the case of forming a pixel portion by an inkjet method using a conventional ink composition. Therefore, it is conceivable to improve the ejection stability by miniaturizing the luminescent nanocrystalline particles and the light-scattering particles, reducing the content of the luminescent nanocrystalline particles and the light-scattering particles, and the like. In this case, the effect of improving the external quantum efficiency tends to decrease, and it is difficult to achieve both excellent ejection stability and excellent external quantum efficiency. On the other hand, according to the ink composition further containing a polymer dispersant, it is possible to achieve both excellent ejection stability and excellent external quantum efficiency. The reason why such an effect is obtained is not clear, but the polymer dispersant significantly suppresses the aggregation of the luminescent nanocrystalline particles and the light-scattering particles (especially the light-scattering particles). It is speculated that

Functional groups that have an 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.

From the viewpoint of the dispersion stability of the light-scattering particles, the side effect of sedimentation of the luminescent nanocrystalline particles, the ease of synthesizing the polymer dispersant, and the stability of the functional group, the acidic functional A carboxyl group, a sulfo group, a phosphonic acid group and a phosphoric acid group are preferably used as the group, and an amino group is preferably used as the basic functional group. Among these, carboxyl group, phosphonic acid group and amino group are more preferably used, and amino group is most preferably used.

Polymeric dispersants with acidic functional groups have an acid value. The acid value of the polymeric dispersant having acidic functional groups is preferably 1-150 mgKOH/g. When the acid value is 1 mgKOH/g or more, sufficient dispersibility of the light-scattering particles is likely to be obtained, and when the acid value is 150 mgKOH/g or less, the storage stability of the pixel portion (cured product of the ink composition) is improved. is difficult to decrease. The acid value of the polymeric dispersant is preferably 50 mgKOH/g or less, more preferably 45 mgKOH/g or less, even more preferably 35 mgKOH/g or less, particularly preferably 30 mgKOH/g or less, and even more preferably 24 mgKOH/g or less.

The acid value of the polymer dispersant was determined by preparing a sample solution in which pg of the polymer dispersant was dissolved in 50 mL of a mixed solution of toluene and ethanol in a volume ratio of 1:1 and 1 mL of phenolphthalein test solution. Titrate with a 1 mol/L ethanolic potassium hydroxide solution (7.0 g of potassium hydroxide dissolved in 5.0 mL of distilled water and adjusted to 1000 mL by adding 95 vol% ethanol) until the sample solution turns pale red. I do. Then, the acid value can be calculated by the following formula.
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.

Polymeric dispersants with basic functional groups have an amine value. The amine value of the polymeric dispersant having a basic functional group is preferably 1-200 mgKOH/g. When the amine value is 1 mgKOH/g or more, sufficient dispersibility of the light-scattering particles is likely to be obtained, and when the amine value is 200 mgKOH/g or less, the storage stability of the pixel portion (cured product of the ink composition) is improved. is difficult to decrease. The amine value of the polymeric dispersant is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more. The amine value of the polymeric dispersant is preferably 90 mgKOH/g or less, more preferably 50 mgKOH/g or less.

The amine value of the polymeric dispersant was determined by dissolving the polymeric dispersant xg in 50 ml of a mixed solution of toluene and ethanol at a volume ratio of 1:1 and 1 ml of bromophenol blue test solution. Titrate with 5 mol/L hydrochloric acid until the sample solution turns green. Then, 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 polymeric dispersant may be a polymer (homopolymer) of a single monomer, or a copolymer (copolymer) of a plurality of types of monomers. Further, the polymeric dispersant may be any of random copolymers, block copolymers and graft copolymers. When the polymeric dispersant is a graft copolymer, it may be 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. It's okay.

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. etc. can be used.

Examples of commercially available products include "DISPERBYK-130", "DISPERBYK-161", "DISPERBYK-162", "DISPERBYK-163", "DISPERBYK-164", "DISPERBYK-166", and "DISPERBYK- 167", "DISPERBYK-168", "DISPERBYK-170", "DISPERBYK-171", "DISPERBYK-174", "DISPERBYK-180", "DISPERBYK-182", "DISPERBYK-183", "DISPERBYK-184" , "DISPERBYK-185", "DISPERBYK-2000", "DISPERBYK-2001", "DISPERBYK-2008", "DISPERBYK-2009", "DISPERBYK-2020", "DISPERBYK-2022", "DISPERBYK-2025", " DISPERBYK-2050", "DISPERBYK-2070", "DISPERBYK-2096", "DISPERBYK-2150", "DISPERBYK-2155", "DISPERBYK-2163", "DISPERBYK-2164", "BYK-LPN21116" and "BYK- LPN6919"; BASF's "EFKA4010", "EFKA4015", "EFKA4046", "EFKA4047", "EFKA4061", "EFKA4080", "EFKA4300", "EFKA4310", "EFKA4320", "EFKA4330", "EFKA43KA4" , "EFKA4560", "EFKA4585", "EFKA5207", "EFKA1501", "EFKA1502", "EFKA1503" and "EFKA PX-4701"; , Solsperse 13650, Solsperse 13940, Solsperse 11200, Solsperse 13940, Solsperse 16000, Solsperse 17000, Solsperse 18000, Solsperse 20000, Solsperse 21000, Solsperse 24000 ”, “Solsperse 26000”, “Solsperse 27000”, “Solsperse 28000”, “Solsperse 32000 ”, “Solsperse 32500”, “Solsperse 32550”, “Solsperse 32600”, “Solsperse 33000”, “Solsperse 34750”, “Solsperse 35100”, “Solsperse 35200”, “Solsperse 36000”, “Solsperse 37500”, “Solsperse 38500 ", "Solspers 39000", "Solspers 41000", "Solspers 54000", "Solspers 71000" and "Solspers 76500"; PN411" and "PA111"; Evonik's "TEGO Dispers 650", "TEGO Dispers 660C", "TEGO Dispers 662C", "TEGO Dispers 670", "TEGO Dispers 685", "TEGO Dispers 700", "TEGO Dispers 60" and "TeGO Dispers 7" Dispers 710 "Disparlon DA-703-50", "DA-705" and "DA-725" manufactured by Kusumoto Kasei Co., Ltd. can be used.

As the polymer dispersant, in addition to the above commercial products, a cationic monomer containing a basic group and/or an anionic monomer having an acidic group, a monomer having a hydrophobic group, and other monomers if necessary. (a nonionic monomer, a monomer having a hydrophilic group, etc.) can be used. Details of cationic monomers, anionic monomers, monomers having a hydrophobic group, and other monomers include monomers described in paragraphs 0034 to 0036 of JP-A-2004-250502.

Further, for example, a compound obtained by reacting a polyalkyleneimine and a polyester compound described in JP-A-54-37082 and JP-A-61-174939, etc., and a polyallylamine described in JP-A-9-169821. A compound in which the amino group of the side chain is modified with polyester, a graft polymer containing a polyester-type macromonomer as a copolymerization component described in JP-A-9-171253, and a polyester polyol addition described in JP-A-60-166318. Preferred examples include polyurethane.

The weight-average molecular weight of the polymer dispersant may be 1000 or more, or 2000 or more, from the viewpoint that the light scattering particles can be well dispersed and the effect of improving the external quantum efficiency can be further improved. There may be, and it may be 3000 or more. The weight-average molecular weight of the polymer dispersant is such that the light scattering particles can be well dispersed, the effect of improving the external quantum efficiency can be further improved, and the viscosity of the inkjet ink can be adjusted for stable ejection. From the viewpoint of obtaining a suitable viscosity, it may be 100,000 or less, 50,000 or less, or 30,000 or less.

From the viewpoint of the dispersibility of the light scattering particles, the content of the polymer dispersant may be 0.5 parts by mass or more, or 2 parts by mass or more with respect to 100 parts by mass of the light scattering particles. It may be 5 parts by mass or more. The content of the polymer dispersion may be 50 parts by mass or less, and 30 parts by mass or less with respect to 100 parts by mass of the light-scattering particles, from the viewpoint of wet heat stability of the pixel portion (cured product of the ink composition). or 10 parts by mass or less.

[solvent]
Examples of solvents include ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol dibutyl ether, diethyl adipate, dibutyl oxalate, dimethyl malonate, diethyl malonate, dimethyl succinate, and diethyl succinate. , 1,4-butanediol diacetate, glyceryl triacetate and the like.

The boiling point of the solvent is preferably 150° C. or higher, more preferably 180° C. or higher, from the viewpoint of continuous ejection stability of the inkjet ink. Further, since the solvent must be removed from the ink composition before it is cured when forming the pixel portion, the boiling point of the solvent is preferably 300° C. or lower from the viewpoint of easy removal of the solvent.

The solvent preferably contains an acetate compound having a boiling point of 150° C. or higher. In this case, the affinity between the luminescent nanocrystalline particles and the solvent is improved, and the luminescent nanocrystalline particles can exhibit excellent luminous properties. Specific examples of acetate compounds having a boiling point of 150° C. or higher include monoacetate compounds such as diethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, and dipropylene glycol methyl ether acetate, and 1,4-butanediol diol. Acetate, diacetate compounds such as propylene glycol diacetate, triacetate compounds such as glycerol triacetate, and the like.

Since the ink composition of the present embodiment uses a photopolymerizable compound, it is possible to disperse the light-scattering particles and the luminescent nanocrystalline particles in the photopolymerizable compound without a solvent. Therefore, according to the ink composition of the present embodiment, the step of removing the solvent by drying is not required when forming the pixel portion.

[Antioxidant]
When the ink composition contains an antioxidant, a decrease in external quantum efficiency tends to be suppressed, and better external quantum efficiency maintenance performance tends to be obtained. The antioxidant is not particularly limited, and for example, conventionally known antioxidants such as phenolic antioxidants, amine antioxidants, phosphorus antioxidants, and sulfur antioxidants can be used. Among these, phosphorus-based antioxidants are preferred, and phosphite triester compounds are more preferred.

The phosphite triester compound may be a compound represented by the formula: P(OR ³ ) ₃ . In the formula, multiple ^R3 's each independently represent a monovalent organic group. Two R ³ 's out of the plurality of R ^3's may combine with each other to form a ring.

The monovalent organic group sufficiently satisfies the required performance unique to inkjet inks, such as compatibility with other components (photopolymerizable compounds, etc.) in inkjet inks, and can further suppress the decrease in the external quantum efficiency of inkjet inks. From the viewpoint, it is preferably a monovalent hydrocarbon group. Examples of monovalent hydrocarbon groups include alkyl groups, aryl groups, and alkenyl groups. The number of carbon atoms in the monovalent hydrocarbon group may be 1 to 30, and may be 4 to 18 from the viewpoint of solubility.

Alkyl groups may be straight or branched. Examples of alkyl groups include 2-ethylhexyl, butyl, octyl, nonyl, decyl, isodecyl, dodecyl, hexadecyl and octadecyl groups.

Examples of the aryl group include a phenyl group, a naphthyl group, a tert-butylphenyl group, a di-tert-butylphenyl group, an octylphenyl group, a nonylphenyl group, an isodecylphenyl group, an isodecylphenyl group and an isodecylnaphthyl group. mentioned.

The monovalent hydrocarbon group is preferably an alkyl group or an aryl group, more preferably an alkyl group or a phenyl group, from the viewpoint of further suppressing a decrease in external quantum efficiency.

At least two of the plurality of ^R3 's are preferably identical to each other. At least one of the plurality of R ³ is preferably a phenyl group, and more preferably at least two of the plurality of R ³ are a phenyl group. At least one of the plurality of R ³ is preferably a phenyl group, and one is an alkyl group (preferably a branched alkyl group). That is, the phosphite triester compound preferably has at least one phenyl group and one alkyl group. When the phosphite triester compound has the above functional group, it sufficiently satisfies the required performance peculiar to the inkjet ink such as compatibility with other components (photopolymerizable compound, etc.) in the inkjet ink, and the fluorescence of the inkjet ink is improved. A decrease in quantum yield is further suppressed.

Specific examples of the compound represented by formula (2) include triphenyl phosphite (triphenylphosphite), 2-ethylhexyldiphenylphosphite, diphenyloctylphosphite and the like.

The content of the phosphite triester compound may be 0.01% by mass or more based on the mass of the non-volatile matter in the ink composition, from the viewpoint of further suppressing a decrease in external quantum efficiency. It may be 1% by mass or more, 1% by mass or more, or 5% by mass or more. The content of the phosphite triester compound is preferably 10% by mass or less based on the mass of the non-volatile matter of the ink composition, since the decrease in the external quantum efficiency can be more effectively suppressed even when a small amount is added. more preferably 7% by mass or less, still more preferably 5% by mass or less, and even more preferably 3% by mass or less. When the content of the phosphite triester compound is within the above range, it is possible to ensure better film strength when forming the coating film, and the phosphite triester compound bleeds to the surface more. It is possible to secure suppressed and excellent external quantum efficiency and its maintenance performance.

The content of the phosphite triester compound may be 0.01 parts by mass or more with respect to 100 parts by mass of the photopolymerizable compound, from the viewpoint of further suppressing the decrease in external quantum efficiency. It may be at least 0.5 parts by mass, at least 1 part by mass, or at least 3 parts by mass. Since a decrease in external quantum efficiency can be more effectively suppressed even if a small amount is added, the content of the phosphite triester compound may be 10 parts by mass or less with respect to 100 parts by mass of the photopolymerizable compound. , 7 parts by mass or less, or 5 parts by mass or less. When the content of the phosphite triester compound is within the above range, it is possible to ensure better film strength at the time of forming the coating film, and the phosphite triester compound bleeds to the surface more. It tends to be possible to suppress it and ensure excellent external quantum efficiency and its maintenance performance.

The phosphite triester compound may be liquid or solid at room temperature (25° C.), but is preferably compatible with other components (photopolymerizable compound, etc.) in the inkjet ink. It is a liquid at room temperature (25° C.) from the viewpoint of sufficiently satisfying the required performance peculiar to inkjet ink and further suppressing a decrease in external quantum efficiency. The melting point of the phosphite triester compound may be 20° C. or lower, or 10° C. or lower.

[thiol compound]
When the ink composition contains a thiol compound, a decrease in external quantum efficiency tends to be suppressed, and better external quantum efficiency maintenance performance tends to be obtained. Although the thiol compound is not particularly limited, a compound having two or three primary mercapto groups in one molecule is preferably used. A primary mercapto group means a mercapto group attached to a primary carbon atom. That is, the thiol compound has —CH ₂ —SH as a partial structure. The number of primary mercapto groups in the thiol compound is preferably 2 or 3, more preferably 2, from the viewpoint of easily suppressing an increase in the viscosity of the ink composition over time.

When the thiol compound has a primary mercapto group, when the ink composition is cured by irradiation with an active energy ray (for example, ultraviolet rays), for example, a secondary or tertiary mercapto group (secondary or tertiary As compared with a thiol compound having a mercapto group bonded to a tertiary carbon atom, it can be cured with a smaller exposure dose (irradiation dose), and a decrease in external quantum efficiency can be more easily suppressed.

The thiol compound may further have a substituted or unsubstituted aliphatic hydrocarbon group in addition to the primary mercapto group, and may further have a carbonyloxy group (--COO--). The thiol compound is preferably a moiety represented by the following formula (2) from the viewpoint of further improving ejection stability, further reducing leakage light, and further suppressing deterioration in external quantum efficiency. have a structure.

In formula (2), n represents an integer of 0 or more, X represents a methylene group ( _--CH.sub.2-- ) or a carbonyl group (--CO--), and * represents a bond. X is preferably a carbonyl group. n may be, for example, 1-10, or 1-5. When X is a carbonyl group, n is preferably 1 or 2, more preferably 2.

The thiol compound is preferably a compound represented by the following formula (3) from the viewpoint of further improving ejection stability, reducing light leakage, and further suppressing a decrease in external quantum efficiency. be.

In formula (3), ^R4 represents an m-valent hydrocarbon group, m represents 2 or 3, and n and X have the same meanings as n in formula (2). R ⁴ is preferably an m-valent substituted or unsubstituted aliphatic hydrocarbon group. The number of carbon atoms in R ⁴ may be 1 or more, or 4 or more, and may be 20 or less, or 10 or less. The substituted aliphatic hydrocarbon group may be one in which some of the hydrogen atoms in the aliphatic hydrocarbon group are substituted with hydroxyl groups, and some of the carbon atoms in the aliphatic hydrocarbon group are substituted with oxygen atoms. may be a base. 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. The (poly)oxyalkylene group may be, for example, a (poly)oxyethylene group.

The viscosity of the thiol compound at 25° C. may be, for example, 20 mPa·s or more, or 100 mPa·s or more, and may be 200 mPa·s or less, or 170 mPa·s or less, from the viewpoint of ejection stability during inkjet printing. may In this specification, the viscosity of a thiol compound is the viscosity measured by an E-type viscometer, for example.

Examples of thiol compounds having three primary mercapto groups include trimethylolpropane tris (3-mercaptopropionate). Examples of thiol compounds having two primary mercapto groups include tetraethylene glycol bis(3-mercaptopropionate). A thiol compound may be used individually by 1 type, and may be used in combination of 2 or more type.

A commercial item can also be used for a thiol compound. Examples of commercially available thiol compounds having three primary mercapto groups include “TMMP” (trade name) and “PEPT” (trade name) manufactured by SC Organic Chemical Co., Ltd. As a commercially available thiol compound having two primary mercapto groups, “EGMP-4” (trade name) manufactured by SC Organic Chemical Co., Ltd. can be mentioned.

The content of the thiol compound is 1.0 parts by mass or more with respect to 100 parts by mass of the ethylenically unsaturated monomer, from the viewpoint of increasing the viscosity of the ink composition over time and further suppressing the decrease in the external quantum efficiency. 8.0 parts by mass or more, or 14.0 parts by mass or more. From the viewpoint of increasing the viscosity of the ink composition over time, the content of the thiol compound may be 32.5 parts by mass or less and 23.0 parts by mass or less with respect to 100 parts by mass of the ethylenically unsaturated monomer. It may be 15.0 parts by mass or less.

The viscosity of the ink composition described above at 40° C. may be, 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. may The viscosity of the ink composition at 40° C. may be 20 mPa·s or less, 15 mPa·s or less, or 12 mPa·s or less. The viscosity of the ink composition at 40° C. is, for example, 2 to 20 mPa·s, 2 to 15 mPa·s, 2 to 12 mPa·s, 5 to 20 mPa·s, 5 to 15 mPa·s, 5 to 12 mPa·s, 7 to It may be 20 mPa·s, 7 to 15 mPa·s, or 7 to 12 mPa·s. In this specification, the viscosity of the ink composition is the viscosity measured by, for example, an E-type viscometer.

The viscosity of the ink composition at 23° C. may be, for example, 5 mPa·s or more, 10 mPa·s or more, or 15 mPa·s or more from the viewpoint of ejection stability during inkjet printing. good. The viscosity of the ink composition at 23° C. may be 40 mPa·s or less, 35 mPa·s or less, 30 mPa·s or less, or 25 mPa·s or less. The viscosity of the ink composition at 23° C. may be, for example, 5 to 40 mPa·s, 10 to 35 mPa·s, 10 to 30 mPa·s, 15 to 30 mPa·s, or 15 to 25 mPa·s.

When the viscosity of the ink composition at 40° C. is 2 mPa·s or more, or when the viscosity of the ink composition at 23° C. is 5 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, ejection control of the inkjet ink (for example, control of ejection amount and ejection timing) is facilitated. On the other hand, when the viscosity of the ink composition at 40° C. is 20 mPa·s or less, or when the viscosity of the ink composition at 40° C. is 40 mPa·s or less, the inkjet ink can be smoothly ejected from the ink ejection holes. can be done.

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 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, 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.

When the ink composition of the present embodiment is used as an ink composition for an ink jet system, it is preferably applied to a piezo jet ink jet recording apparatus using 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).

Although one embodiment of the ink composition for color filters has been described above, the ink composition of the embodiment described above can also be used in, for example, a photolithography system in addition to the ink jet system. In this case, the ink composition contains an alkali-soluble resin as a binder polymer.

When the ink composition is used in photography, first, the ink composition is applied onto a substrate, and when the ink composition contains a solvent, the ink composition is further dried to form a coating film. The coating film thus obtained is soluble in an alkaline developer, and is patterned by being treated with an alkaline developer. At this time, the alkali developer is mostly an aqueous solution from the viewpoint of ease of disposal of the waste liquid of the developer, and therefore the coating film of the ink composition is treated with an aqueous solution. On the other hand, in the case of an ink composition using luminescent nanocrystalline particles (quantum dots, etc.), the luminescent nanocrystalline particles are unstable against water, and luminescence (for example, fluorescence) is impaired by moisture. For this reason, in the present embodiment, the ink jet method is preferable because it does not require treatment with an alkaline developer (aqueous solution).

In addition, even when the coating film of the ink composition is not treated with an alkaline developer, if the ink composition is alkali-soluble, the coating film of the ink composition easily absorbs moisture in the atmosphere. Luminescent properties (for example, fluorescence) of luminescent nanocrystalline particles (quantum dots, etc.) deteriorate over time. From this point of view, in the present embodiment, the coating film of the ink composition is preferably alkali-insoluble. That is, the ink composition of the present embodiment is preferably an ink composition capable of forming an alkali-insoluble coating film. Such an ink composition can be obtained by using an alkali-insoluble photopolymerizable compound as the photopolymerizable compound. The fact that the coating film of the ink composition is alkali-insoluble means that the amount of the coating film of the ink composition dissolved in a 1% by mass aqueous potassium hydroxide solution at 25° C. is, based on the total mass of the coating film of the ink composition, It means that it is 30% by mass or less. The amount of the ink composition dissolved in the coating film is preferably 10% by mass or less, and more preferably 3% by mass or less. It should be noted that the fact that the ink composition is an ink composition capable of forming an alkali-insoluble coating film means that after the ink composition is applied onto the substrate, it is dried under the conditions of 80° C. for 3 minutes when the ink composition contains a solvent. It can be confirmed by measuring the amount of dissolution of the obtained coating film having a thickness of 1 μm.

<Method for producing ink composition>
The ink composition of the embodiment described above is obtained, for example, by mixing the components of the ink composition described above and performing a dispersion treatment. As an example, a method for producing an ink composition containing light-scattering particles and a polymer dispersant will be described below.

A method for producing an ink composition includes, for example, a first step of preparing a dispersion of light-scattering particles containing light-scattering particles and a polymer dispersant, and a second step of mixing the crystal grains. In this method, the dispersion of light-scattering particles may further contain a photopolymerizable compound, and the photopolymerizable compound may be further mixed in the second step. According to this method, the light scattering particles can be sufficiently dispersed. Therefore, it is possible to improve the optical properties (for example, external quantum efficiency) of the pixel portion, and easily obtain a luminescent ink composition excellent in ejection stability.

In the step of preparing a dispersion of light-scattering particles, light-scattering particles, a polymer dispersant, and optionally a photopolymerizable compound are mixed, and a dispersion treatment is performed to obtain a dispersion of light-scattering particles. may be prepared. 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. By mixing the light-scattering particles and the polymer dispersing agent before mixing the light-emitting nanocrystalline particles and the light-scattering particles, the light-scattering particles can be more fully dispersed. Therefore, excellent ejection stability and excellent external quantum efficiency can be obtained more easily.

The method for producing the ink composition may further comprise, before the second step, a step of preparing a dispersion of luminescent nanocrystalline particles containing luminescent nanocrystalline particles and a photopolymerizable compound. good. In this case, in the second step, a dispersion of light-scattering particles and a dispersion of luminescent nanocrystalline particles are mixed. In the step of preparing a dispersion of luminescent nanocrystalline particles, luminescent nanocrystalline particles and a photopolymerizable compound may be mixed and subjected to dispersion treatment to prepare a luminescent nanocrystalline particle dispersion. Luminescent nanocrystalline particles may be luminescent nanocrystalline particles having organic ligands on their surfaces. That is, the luminescent nanocrystalline particle dispersion may further contain an organic ligand. 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, a paint conditioner, or a jet mill from the viewpoint of improving the dispersibility of the luminescent nanocrystalline particles and facilitating adjustment of the average particle size of the luminescent nanocrystalline particles to a desired range. According to this method, the luminescent nanocrystalline particles can be sufficiently dispersed. Therefore, it is possible to improve the optical properties (for example, external quantum efficiency) of the pixel portion, and easily obtain an ink composition having excellent ejection stability.

In this production method, other components (for example, solvent, antioxidant, thiol compound, etc.) other than the components described above may be further used. In this case, the other component may be contained in the luminescent nanocrystalline particle dispersion or the light-scattering particle dispersion. Other ingredients may also be mixed with the composition obtained by mixing the luminescent nanocrystalline particle dispersion and the light scattering particle dispersion.

<Cured product of ink composition>
A cured product of the ink composition of one embodiment (hereinafter also referred to as “cured ink product”) contains luminescent nanocrystalline particles and a curing component, and the curing component comprises a polymer containing a structural unit having an ether ring. Contains coalescence. This cured ink product can be obtained, for example, by curing the ink composition of the embodiment described above. Therefore, the cured ink may contain each component (excluding the volatile matter) contained in the ink composition of the embodiment described above, and may further contain, for example, light-scattering particles. When the ink composition is cured, the cured organic component in the ink composition becomes the cured component.

The luminescent nanocrystalline particles contained in the ink cured product may be the luminescent nanocrystalline particles contained in the ink composition described above. The content of the luminescent nanocrystalline particles in the cured ink composition is preferably 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. is more than 20% by mass, more preferably 23% by mass or more, and still more preferably 25% by mass or more. The content of the luminescent nanocrystalline particles is preferably 50% by mass or less based on the total mass of the cured ink, from the viewpoint of obtaining excellent pixel unit reliability and excellent emission intensity. From the same point of view, the content of the luminescent nanocrystalline particles may be 40% by mass or less, 35% by mass or less, or 30% by mass or less based on the total mass of the cured ink. There may be.

The polymer contained in the cured ink (polymer containing a structural unit having an ether ring) is a polymer obtained by polymerization of the above-described first photopolymerizable compound (for example, radical polymer).

A structural unit having an ether ring is, for example, a structural unit that constitutes the main chain skeleton of a polymer, and through a carbon-carbon bond that constitutes an ether ring, another structural unit (for example, a structural unit having an ether ring). Join. The ether ring in the structural unit having an ether ring may be a 4-membered ring, a 5-membered ring or a 6-membered ring, preferably a 5-membered ring. A structural unit having an ether ring is preferably a structural unit having a tetrahydrofuran ring.

［式（ＩＶ）中、＊は結合手を示す。Ｘ^１は式（Ｉ）におけるＸと同義であり、Ｙ^１は式（Ｉ）におけるＹと同義である。重合体における複数のＸ^１は互いに同一であっても異なっていてもよく、複数のＹ^１は互いに同一であっても異なっていてもよい。］ A structural unit having an ether ring is, for example, a structural unit represented by the following formula (IV).

[In Formula (IV), * indicates a bond. X ¹ has the same definition as X in Formula (I), and Y ¹ has the same definition as Y in Formula (I). A plurality of X ¹ 's in the polymer may be the same or different, and a plurality of Y ¹ 's may be the same or different. ]

［式（ＩＶａ）中、＊は結合手を示す。Ｒ^１ａは式（ＩＩＩ）におけるＲ^１と同義である。重合体における複数のＲ^１ａは互いに同一であっても異なっていてもよい。］ X ¹ is preferably a group represented by formula (III) above, and Y ¹ is preferably a methylene group. That is, the structural unit having an ether ring is preferably a structural unit represented by formula (IVa) below.

[In the formula (IVa), * indicates a bond. R ^1a has the same definition as R ¹ in formula (III). Plural R ^1a in the polymer may be the same or different. ]

R ^1a is preferably an alkyl group, more preferably a methyl group.

［式（Ｖ）中、＊は結合手を示す。Ｘ^２は式（Ｉ）におけるＸと同義であり、Ｙ^２は式（Ｉ）におけるＹと同義である。重合体における複数のＸ^２は互いに同一であっても異なっていてもよく、複数のＹ^２は互いに同一であっても異なっていてもよい。Ｘ^２はＸ^１と同一であっても異なっていてもよい。Ｙ^２はＹ^１と同一であっても異なっていてもよい。］ A polymer containing a structural unit having an ether ring may consist only of a structural unit represented by formula (IV), or may consist only of a structural unit represented by formula (IVa). A polymer containing a structural unit having an ether ring may further contain a structural unit represented by the following formula (V) in addition to the structural unit represented by the formula (IV).

[In the formula (V), * indicates a bond. X ² has the same definition as X in Formula (I), and Y ² has the same definition as Y in Formula (I). A plurality of ^X2 's in the polymer may be the same or different, and a plurality of ^Y2 's may be the same or different. ^X2 may be the same as or different from ^X1 . ^Y2 may be the same as or different from ^Y1 . ]

［式（Ｖａ）中、＊は結合手を示す。Ｒ^１ｂは式（ＩＩＩ）におけるＲ^１と同義である。重合体における複数のＲ^１ｂは互いに同一であっても異なっていてもよい。Ｒ^１ａとＲ^１ｂとは同一であっても異なっていてもよい。］ ^X2 is preferably a group represented by formula (III) above, and ^Y2 is preferably a methylene group. That is, the structural unit represented by formula (V) is preferably a structural unit represented by formula (Va) below.

[In the formula (Va), * indicates a bond. R ^1b has the same definition as R ¹ in formula (III). Plural R ^1b in the polymer may be the same or different. R ^1a and R ^1b may be the same or different. ]

R ^1b is preferably an alkyl group, more preferably a methyl group.

A polymer containing a structural unit having an ether ring may consist only of a structural unit represented by formula (IV) and a structural unit represented by formula (V) below, and may contain other structural units different from these. It may further contain: A polymer containing a structural unit having an ether ring may consist only of a structural unit represented by formula (IVa) and a structural unit represented by formula (Va) below.

When the sum of the structural unit represented by formula (IV) and the structural unit represented by formula (V) in the polymer containing a structural unit having an ether ring is 100, represented by formula (IV) The proportion of structural units may be 95 or more, 80 or more, or 50 or more. The proportion of structural units represented by formula (IV) in the polymer is preferably 100. That is, the polymer preferably does not contain structural units represented by formula (V).

The ratio of the structural unit represented by formula (IVa) is 95 or more, 80 or more, or It may be 50 or more. The proportion of structural units represented by formula (IVa) in the polymer is preferably 100.

The content of the light-scattering particles in the cured ink may be 0.1% by mass or more, or 1% by mass or more, based on the total mass of the cured ink, from the viewpoint of improving the external quantum efficiency. 5% by mass or more, 7% by mass or more, 10% by mass or more, or 12% by mass or more. The content of the light-scattering particles may be 60% by mass or less, or 50% by mass, based on the total mass of the cured ink, from the viewpoint of improving the external quantum efficiency and improving the reliability of the pixel portion. % or less, 40% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, or 15% by mass % or less.

<Ink composition set>
An ink composition set of one embodiment includes the ink composition of the embodiment described above. The ink composition set includes an ink composition that does not contain luminescent nanocrystal particles (non-luminescent ink composition) in addition to the ink composition (luminescent ink composition) of the embodiment described above. good. The non-luminescent ink composition may be a conventionally known photopolymerizable ink composition, and the ink composition of the above-described embodiment (luminescent ink composition It may have the same composition as the product).

Since the non-luminous ink composition does not contain luminous nanocrystal particles, the pixel portion formed by the non-luminous ink composition (the pixel portion containing the cured non-luminous ink composition) is exposed to light. is incident, the light emitted from the pixel portion has substantially the same wavelength as the incident light. Therefore, a 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 the light incident on the pixel portion. , the light intensity difference in the viewing angle of the light emitted from the pixel portion can be reduced.

<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 of one embodiment. As shown in FIG. 1 , the color filter 100 includes a base material 40 and a light conversion layer 30 provided on the base material 40 . The light conversion layer 30 includes a plurality of pixel portions 10 and a light shielding portion 20 .

The light conversion layer 30 has, as the pixel units 10, a first pixel unit 10a, a second pixel unit 10b, and a third pixel unit 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 the cured ink of the above-described embodiment (for example, the cured ink composition of the embodiment). be. The cured product contains luminescent nanocrystalline particles, a curing component, and light scattering particles. The curing component includes a polymer of photopolymerizable compounds. That is, the first pixel portion 10a includes a first curing component 13a, and first luminescent nanocrystalline particles 11a and first light-scattering particles 12a dispersed in the first curing component 13a. include. 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. 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 and the content of the light scattering particles in the luminescent pixel portion are the same as the ranges described above for the content of the luminescent nanocrystalline particles and the content of the light scattering particles in the ink cured product. It's okay. In this case, the "total mass of the cured ink" is replaced with the "total mass of the pixel portion".

The third pixel portion 10c is a non-luminous pixel portion (non-luminous pixel portion) containing a cured product of the non-luminous ink composition described above. The cured product does not contain luminescent nanocrystalline particles, but contains light-scattering particles and a curing component. Curing components include, for example, polymers of photopolymerizable compounds. 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 light scattering particles 12c may be the same as or different from the first light scattering particles 12a and the second light scattering particles 12b.

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

The light shielding portion 20 is a so-called black matrix provided for the purpose of separating adjacent pixel portions 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. The thickness of the light shielding portion 20 may be, for example, 0.5 μm or more and 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.

For example, the color filter 100 is formed by forming the light-shielding portions 20 in a pattern on the substrate 40, and then applying the ink composition of the above-described embodiment ( Inkjet ink) is selectively deposited by an inkjet method, and the ink composition is cured by irradiation with an active energy ray or by heating.

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

When the ink composition is cured by irradiation with active energy rays (eg, ultraviolet rays), for example, a mercury lamp, metal halide lamp, xenon lamp, LED, or the like may be used. The wavelength of the irradiated light may be, for example, 200 nm or more and 440 nm or less. The exposure dose may be, for example, 10 mJ/cm ² or more and 4000 mJ/cm ² or less.

The drying temperature for volatilizing the solvent may be, for example, 50° C. or higher and 150° C. or lower. The drying time may be, for example, 3 minutes or more and 30 minutes 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 part). In addition, the light conversion layer includes a pixel portion (for example, a yellow pixel portion) 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 too. 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.

Moreover, 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.

Further, the color filter may include an ink-repellent layer made of an ink-repellent material and 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.

Moreover, the color filter may have an ink-receiving layer containing hydroxypropylcellulose, polyvinyl alcohol, gelatin or the like between the substrate 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.

Further, in manufacturing the color filter and the light conversion layer, the pixel portion may be formed by the photolithography method instead of the inkjet method. In this case, first, the ink composition is applied to the base material in layers to form an ink composition layer. Next, after the ink composition layer is exposed in a pattern, it is developed using a developer. Thus, a pixel portion made of a cured product of the ink composition is formed. Since the developer is usually alkaline, an alkali-soluble material is used as the material for the ink composition. However, the ink jet method is superior to the photolithography method from the viewpoint of efficiency in using materials. This is because the photolithographic method, in principle, removes approximately two-thirds or more of the material, thus wasting the material. Therefore, in the present embodiment, it is preferable to use inkjet ink and form the pixel portion by an inkjet method.

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. For example, when a pixel portion containing luminescent nanocrystalline particles that absorbs blue light and emits light is adopted as the pixel portion of the liquid crystal display element, the light from the light source is blue light or quasi-white light having a peak at 450 nm. However, if the concentration of the luminescent nanocrystalline particles in the pixel portion is insufficient, the light from the light source passes through the light conversion layer when the liquid crystal display element is driven. The transmitted light (blue light, leakage light) from this light source and the light emitted by the luminescent nanocrystal particles are mixed. From the viewpoint of preventing deterioration in color reproducibility due to such color mixture, the pixel portion of the light conversion layer may contain a pigment. 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 The pixel portion may contain a coloring material without containing crystal grains. 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 copper phthalocyanine halide 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. %.

EXAMPLES 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. Titanium oxide was used after being heated at 175° C. for 4 hours under a reduced pressure of 1 mmHg and left to cool in an argon gas atmosphere before mixing. The liquid materials used in the examples were dehydrated with molecular sieves 3A for 48 hours or more before mixing.

<Preparation of photopolymerizable compound>
The following photopolymerizable compounds were prepared.
・AOMA (methyl 2-allyloxymethyl acrylate, manufactured by Nippon Shokubai Co., Ltd., trade name: FX-AO-MA)
・HDDMA (1,6-hexanediol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester HD-N)
・ EOEOEA (ethoxyethoxyethyl acrylate, manufactured by MIWON, trade name: Miramer M170)

<Example 1>
(Preparation of green-emitting InP/ZnSeS/ZnS nanocrystalline particle dispersion)
[Synthesis of core (InP core) of green-emitting nanocrystalline particles]
5 g of trioctylphosphine oxide (TOPO), 1.46 g (5 mmol) of indium acetate and 3.16 g (15.8 mmol) of lauric acid were added to the reaction flask to obtain a mixture. The mixture was heated at 160° C. for 40 minutes under nitrogen (N 2 ) atmosphere and then at 250° C. for 20 minutes under vacuum. The reaction temperature (temperature of the mixture) was then raised to 300° C. under a nitrogen (N2) environment. At this temperature, a mixture of 3 g of 1-octadecene (ODE) and 0.25 g (1 mmol) of tris(trimethylsilyl)phosphine was rapidly introduced into the reaction flask and the reaction temperature was maintained at 260°C. After 5 minutes, the reaction was stopped by removing the heater and the resulting reaction solution was cooled to room temperature. 8 ml of toluene and 20 ml of ethanol were then added to the reaction solution in the glove box. Subsequently, centrifugation was performed to precipitate InP nanocrystalline particles (InP cores), and then the supernatant was decanted to obtain InP nanocrystalline particles (InP cores). Next, the obtained InP nanocrystalline particles (InP cores) were dispersed in hexane to obtain a dispersion (hexane dispersion) containing 5% by mass of InP nanocrystalline particles (InP cores).

[Synthesis of green-emitting nanocrystalline particle shell (ZnSeS/ZnS shell)]
After adding 2.5 g of the hexane dispersion of the InP nanocrystalline particles (InP cores) obtained above to the reaction flask, 0.7 g of oleic acid was added to the reaction flask at room temperature, and the temperature was raised to 80°C. rice field. Then, 14 mg of diethylzinc, 8 mg of bis(trimethylsilyl)selenide and 7 mg of hexamethyldisilathiane (ZnSeS precursor solution) dissolved in 1 ml of ODE were added dropwise into the reaction mixture to achieve a thickness of 0.5 monolayer. A ZnSeS shell was formed.

After dropping the ZnSeS precursor solution, the reaction temperature was kept at 80° C. for 10 minutes. The temperature was then raised to 140° C. and held for 30 minutes. Next, a ZnS precursor solution obtained by dissolving 69 mg of diethylzinc and 66 mg of hexamethyldisilathiane in 2 ml of ODE was added dropwise into the reaction mixture to form a ZnS shell with a thickness of 2 monolayers. . Ten minutes after the addition of the ZnS precursor solution, the reaction was stopped by removing the heater. The reaction mixture was then cooled to room temperature and the resulting white precipitate was removed by centrifugation to yield a transparent nanocrystalline particle dispersion (ODE dispersion) with green-emitting InP/ZnSeS/ZnS nanocrystalline particles dispersed therein. ).

[Synthesis of organic ligands for InP/ZnSeS/ZnS nanocrystalline particles]
(Synthesis of organic ligand)
After introducing polyethylene glycol |average Mn400| (manufactured by Sigma-Aldrich) into the flask, while stirring in a nitrogen gas environment, polyethylene glycol |average Mn400| made) was added. The internal temperature of the flask was raised to 80° C. and stirred for 8 hours to obtain an organic ligand represented by the following formula (A) as a pale yellow viscous oil.

[Preparation of Green-Emitting InP/ZnSeS/ZnS Nanocrystalline Particle Dispersion by Ligand Exchange]
30 mg of the above organic ligand was added to 1 ml of the ODE dispersion of InP/ZnSeS/ZnS nanocrystalline particles obtained above. Ligand exchange was then performed by heating at 90° C. for 5 hours. Aggregation of nanocrystalline particles was observed as the ligand exchange progressed. After completion of ligand exchange, the supernatant was decanted to obtain nanocrystalline particles. Then, 3 ml of ethanol was added to the resulting nanocrystalline particles, and ultrasonically treated to redisperse them. 10 ml of n-hexane was added to 3 ml of the obtained ethanol dispersion of nanocrystalline particles. Subsequently, after centrifugation to precipitate nanocrystalline particles, the supernatant was decanted and dried under vacuum to obtain nanocrystalline particles (InP/ZnSeS/ZnS nanocrystalline particles modified with the above organic ligands). The content of organic ligands in the total amount of nanocrystalline particles modified with organic ligands was 30% by mass. By dispersing the obtained nanocrystalline particles (InP/ZnSeS/ZnS nanocrystalline particles modified with the above organic ligands) in a photopolymerizable compound so that the content in the dispersion is 50% by mass, A green luminescent nanocrystalline particle dispersion was obtained. AOMA was used as the photopolymerizable compound. The content of AOMA in the dispersion was 50 wt%.

(Preparation of light-scattering particle dispersion)
In a container filled with argon gas, 33.0 g of titanium oxide (trade name: CR-60-2, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 210 nm) and a polymer dispersant (product Name: Ajisper PB-821, manufactured by Ajinomoto Fine-Techno Co., Ltd.) and 26.0 g of AOMA are mixed, then zirconia beads (diameter: 1.25 mm) are added to the resulting mixture, and a paint conditioner is used. The mixture was subjected to dispersion treatment by shaking for 2 hours, and the zirconia beads were removed with a polyester mesh filter to obtain a light-scattering particle dispersion 1 (titanium oxide content: 55% by mass).

(Preparation of ink composition)
A green-emitting nanocrystalline particle dispersion, a light-scattering particle dispersion, and a photopolymerization initiator phenyl (2,4,6-trimethylbenzoyl) ethyl phosphinate (manufactured by IGM resin, trade name: Omnirad TPO- L, molecular weight: 316) were blended so that the content of each component in the ink composition was as shown in Table 1, and mixed uniformly in a vessel filled with argon gas. After that, the mixture was filtered through a filter with a pore size of 3 μm in a glove box. Furthermore, argon gas was introduced into the container containing the obtained filtrate, and the inside of the container was saturated with argon gas. Then, the ink composition of Example 1 was obtained by removing the argon gas under reduced pressure. The content of the luminescent nanocrystalline particles shown in Table 1 includes the content of the organic ligand (7.7 parts by mass).

<Example 2>
AOMA and HDDDMA were used as photopolymerizable compounds in the preparation of the luminescent nanocrystal particle dispersion, and the content of each component in the ink composition was adjusted to the content shown in Table 1. An ink composition of Example 2 was prepared in the same manner as in Example 1, except that each component was blended in.

<Example 3>
Tetraethylene glycol bis(3-mercaptopropionate) ( SC Organic Chemical Co., Ltd., trade name: EGMP-4) was used, 2-ethylhexyldiphenyl phosphite (ADEKA Co., Ltd., Adekastab C) was used as an antioxidant, and in the ink composition An ink composition of Example 3 was prepared in the same manner as in Example 1, except that each component was blended so that the content of each component of was as shown in Table 1.

<Comparative Example 1>
EOEOEA was used as the photopolymerizable compound in place of AOMA in the preparation of the luminescent nanocrystal particle dispersion, and the content of each component in the ink composition was as shown in Table 2. An ink composition of Comparative Example 1 was prepared in the same manner as in Example 1, except that each component was blended as follows.

<Evaluation>
[Preparation of sample for evaluation]
Each ink composition was applied on a glass substrate in the atmosphere using a spin coater to a thickness of 10 μm. Under a nitrogen atmosphere, the coating film is cured by irradiating UV with a conveyor type UV irradiation device manufactured by Sen Engineering Co., Ltd. (trade name “UV3001DT-1C”) so that the cumulative light amount becomes 1000 mJ / cm ² , and cured on the glass substrate. A layer (light conversion layer) composed of a cured product of the ink composition was formed. Thus, each evaluation sample, which is a substrate having a light conversion layer, was produced.

[External quantum efficiency (EQE) evaluation]
A blue LED (peak emission wavelength: 450 nm) manufactured by CCS Co., Ltd. was used as a surface emitting light source. As a measurement device, an integrating sphere was connected to a radiation spectrophotometer (trade 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.
EQE (%) = P1 (Green)/E (Blue) x 100

Here, E (Blue) and P1 (Green) respectively represent the following.
E (Blue): Represents the total value of “illuminance×wavelength/hc” in the wavelength range of 380 to 490 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.

The EQE measured immediately after the evaluation sample was prepared was taken as the initial external quantum efficiency (EQE ₀ ), and after measuring EQE ₀ , the evaluation sample was used as an accelerated test for measuring the EQE after a long period of time. was stored in a glove box manufactured by MBRAUN (trade name “Labmaster Pro DP”) under a nitrogen atmosphere for one week. After the test, the external quantum efficiency (EQE _h ) was measured, and the EQE retention rate was calculated based on the following formula. The results are shown in Tables 1 and 2.
EQE retention rate = EQE _h / EQE ₀ × 100

[Viscosity evaluation]
After preparation, the ink composition was stored under an environment of 23° C. and 50% RH for one week. The viscosity of the stored ink composition was measured using an E-type viscometer. Viscosity measurements were performed at 25°C. The results are shown in Tables 1 and 2.

[Evaluation of Ejection Stability]
After preparation, the ink composition was stored under an environment of 23° C. and 50% RH for one week. The ink composition after storage was subjected to an ejection test using an inkjet printer (manufactured by Fuji Film Dimatix, trade name "DMP-2831"). In the ejection test, the ink composition was ejected continuously for 10 minutes at room temperature. 16 nozzles were formed in the head section for ejecting the ink of this inkjet printer, and the amount of the ink composition used per ejection per nozzle was 10 pL. The ejection stability of the ink compositions of Examples and Comparative Examples was evaluated according to the following criteria. The results are shown in Tables 1 and 2.
A: Continuous ejection possible (continuous ejection possible with 10 or more nozzles out of 16 nozzles)
B: Continuous discharge not possible (9 nozzles or less out of 16 nozzles capable of continuous discharge)
C: Unable to discharge

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 (15)

luminescent nanocrystalline particles;
a first photopolymerizable compound containing an allyl ether group and an ethylenically unsaturated group capable of forming an intramolecular ring by reacting with the allyl ether group;
contains
The first photopolymerizable compound is an ink composition containing a structure represented by the following formula (II) as a structure having an ethylenically unsaturated group (represented by the following formula (4) ( excluding ink compositions containing meth)acrylamide compounds) .

[In Formula (II), * indicates a bond. ]

[In formula (4), R ¹¹ represents a methyl group or a hydrogen atom, and R ¹² represents a linear alkylene group having 1 to 6 carbon atoms. ] When a photopolymerizable compound different from the first photopolymerizable compound is used as the second photopolymerizable compound, the content of the second photopolymerizable compound with respect to the content of the first photopolymerizable compound 2. The ink composition of claim 1, wherein the ratio is 0.8 or less. 3. The ink composition according to claim 1, further comprising a monofunctional or polyfunctional (meth)acrylate as a second photopolymerizable compound different from the first photopolymerizable compound . The ink composition according to any one of claims 1 to 3, wherein the content of the luminescent nanocrystalline particles is more than 20% by mass based on the mass of non-volatile matter of the ink composition. 5. The ink composition according to any one of claims 1 to 4, further comprising a thiol compound. The ink composition according to any one of claims 1 to 5, further comprising an antioxidant. The ink composition according to any one of claims 1 to 6, further comprising light scattering particles. The ink composition according to any one of claims 1 to 7, wherein the content of the inorganic component is 30% by mass or more based on the mass of the nonvolatile matter of the ink composition. The ink composition according to any one of claims 1 to 8, which is used for forming a light conversion layer. The ink composition according to any one of claims 1 to 9, which is used in an inkjet system. A cured product of the ink composition according to any one of claims 1 to 10,
A cured product of an ink composition containing luminescent nanocrystalline particles and a polymer containing a structural unit having an ether ring. comprising a plurality of pixel portions and a light shielding portion provided between the plurality of pixel portions;
The light conversion layer, wherein the plurality of pixel portions have luminescent pixel portions containing the cured product of the ink composition according to any one of claims 1 to 10 or the cured product according to claim 11. 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;
13. The light conversion layer of claim 12, comprising: 14. The light conversion layer according to claim 12 or 13, further comprising non-emissive pixel portions containing light scattering particles. A color filter comprising the light conversion layer according to any one of claims 12-14.

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