JP7087775B2 - Ink composition, light conversion layer and color filter - Google Patents

Description

The present invention relates to ink compositions, light conversion layers and color filters.

Conventionally, a pixel portion (color filter pixel portion) in a display such as a liquid crystal display device is a curable resist containing, for example, red organic pigment particles or green organic pigment particles, an alkali-soluble resin and / or an acrylic monomer. It has been manufactured by photolithography 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, luminescent nanocrystal particles such as quantum dots, quantum rods, and other inorganic phosphor particles have been strongly demanded. A method of forming a pixel portion such as a red pixel and a green pixel by using the above is being actively studied.

By the way, the method for manufacturing a color filter by the above photolithography method has a drawback that a resist material other than a pixel portion including relatively expensive luminescent nanocrystal particles is wasted due to the characteristics of the manufacturing method. Under such circumstances, in order to eliminate the waste of the resist material as described above, it has begun to be studied to form the pixel portion of the optical conversion substrate by the inkjet method (inkjet method) (Patent Document 1).

International Publication No. 2008/001693

The viscosity of the ink composition tends to increase as the solid content concentration increases. In particular, when luminescent nanocrystal particles are blended, the increase in the viscosity of the ink composition is remarkable. In the inkjet method, if the viscosity of the ink composition becomes too high, it becomes difficult to eject the ink stably. Therefore, an increase in the viscosity of the ink composition causes a decrease in production efficiency.

On the other hand, if the concentration of the luminescent nanocrystal particles in the ink composition is lowered in order to lower the viscosity of the ink composition, the concentration of the luminescent nanocrystal particles in the pixel portion that can be formed by one ejection is lowered. Alternatively, since the thickness of the formed pixel portion becomes thin, it becomes difficult to obtain sufficient optical performance (light emission efficiency, etc.). Therefore, in order to obtain sufficient optical performance, it is necessary to repeat the process of forming the pixel portion a plurality of times, which lowers the production efficiency.

If the increase in viscosity of the ink composition due to the blending of the luminescent nanocrystal particles can be suppressed, the solid content concentration of the ink composition can be increased without lowering the production efficiency. Further, it is expected that the variation in the viscosity of the ink composition due to the variation in the blending amount of the luminescent nanocrystal particles will be small, and the advantages such as improvement in production stability will be obtained.

Therefore, an object of the present invention is to provide an ink jet ink composition in which an increase in viscosity due to luminescent nanocrystal particles is suppressed.

The present inventors have a case where the luminescent nanoparticles have an organic ligand on the surface thereof, and when a specific organic ligand and a specific organic solvent are combined, the rate of increase in the viscosity of the ink composition, that is, the ink We have found that the ratio of the viscosity of the luminescent nanocrystal particles after the compounding to the viscosity of the luminescent nanocrystalline particles before the compounding (viscosity of the organic solvent) in the composition becomes small, and completed the present invention.

That is, one aspect of the present invention relates to an ink composition for inkjet containing luminescent nanocrystal particles, a photopolymerizable compound and / or a thermosetting resin, and an organic solvent. The concentration of the luminescent nanocrystal particles in this ink composition is 10% by mass or more. In addition, the luminescent nanocrystal particles have an organic ligand on the surface thereof. The organic ligand comprises one or more functional groups capable of binding to the luminescent nanocrystal particles and a polyoxyalkylene group. The organic solvent contains a polyoxyalkylene group having the same oxyalkylene structure as that of the polyoxyalkylene group, and does not contain an ester group.

In the inkjet ink composition according to one aspect of the present invention, the increase in viscosity due to the luminescent nanocrystal particles is suppressed. Therefore, according to the inkjet ink composition on one aspect of the present invention, the thickness of the pixel portion that can be formed by one ejection can be increased, and the production efficiency can be improved.

［式（１）中、Ｒ^１及びＲ^２は、それぞれ独立して、水素原子、メチル基又はエチル基を示し、＊は結合手を示す。］ The polyoxyalkylene group contained in the organic ligand may have an oxyalkylene structure represented by the following formula (1).

[In the formula (1), R ¹ and R ² independently represent a hydrogen atom, a methyl group or an ethyl group, and * indicates a bond. ]

The degree of polymerization of the polyoxyalkylene group contained in the organic solvent may be 2 to 4.

Both ends of the main chain of the organic solvent may be alkyl groups having 1 to 4 carbon atoms.

［式（２）中、複数のＲ^１及びＲ^２は、それぞれ独立して、水素原子、メチル基又はエチル基を示し、Ｒ^３及びＲ^４は、それぞれ独立して、炭素数１～４のアルキル基を示し、ｎは２～４の整数を示す。］ The organic solvent may be a compound represented by the following formula (2).

[In the formula (2), a plurality of R ¹ and R ² independently represent a hydrogen atom, a methyl group or an ethyl group, and R ³ and R ⁴ independently have 1 to 4 carbon atoms. It represents an alkyl group, where n is an integer of 2-4. ]

The weight average molecular weight of the organic ligand may be 350 or more.

The ink composition for inkjet may further contain light-scattering particles.

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

One aspect of the present invention includes a plurality of pixel portions and a light-shielding portion provided between the plurality of pixel portions, and the plurality of pixel portions are luminescent including a cured product of the above-mentioned inkjet ink composition. The present invention relates to an optical conversion layer having a pixel portion.

The light conversion layer contains, as a light emitting pixel portion, light emitting nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having a light emitting peak wavelength in the range of 605 to 665 nm. The sex pixel portion and the second luminescent pixel portion containing luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having a emission peak wavelength in the range of 500 to 560 nm. You may be prepared.

The light conversion layer may further include a non-light emitting pixel portion containing light scattering particles.

One aspect of the present invention relates to a color filter including the above-mentioned optical conversion layer.

According to the present invention, it is possible to provide an ink jet ink composition in which an increase in viscosity due to luminescent nanocrystal particles is suppressed.

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

Hereinafter, embodiments of the present invention will be described in detail.

<Ink composition>
The ink composition of one embodiment is a luminescent ink composition containing luminescent nanocrystal particles, a photopolymerizable compound and / or a thermosetting resin, and an organic solvent. The concentration of the luminescent nanocrystal particles in this ink composition, that is, the content of the luminescent nanocrystal particles based on the total mass of the ink composition is 10% by mass or more. In addition, the luminescent nanocrystal particles have an organic ligand on the surface thereof. The organic ligand comprises one or more functional groups capable of binding to the luminescent nanocrystal particles and a polyoxyalkylene group. The organic solvent contains a polyoxyalkylene group having the same oxyalkylene structure as that of the polyoxyalkylene group (polyoxyalkylene group contained in the organic ligand), and does not contain an ester group.

In the above ink composition, the increase in viscosity caused by the luminescent nanocrystal particles is suppressed. That is, the ratio of the viscosity of the luminescent nanocrystal particles after the compounding (viscosity increase rate) to the viscosity of the luminescent nanocrystal particles before the compounding (viscosity of the organic solvent) in the ink composition is low. Therefore, the ink composition can be easily adjusted with a high luminescent nanocrystal particle concentration of 10% by mass or more and a desired viscosity. According to the above ink composition, when used in the ink jet method, good ejection stability can be easily obtained, and production efficiency (for example, production efficiency of a color filter) can be improved.

The reason why such an effect can be obtained is not clear, but the fact that the organic ligand and the organic solvent have a group having the same oxyalkylene structure (polyoxyalkylene group) and that the organic solvent does not contain an ester structure In the above ink composition, the affinity between the organic ligand and the organic solvent is high, and it is presumed that the luminescent nanoparticles are easily uniformly dispersed in the organic solvent.

The ink composition of one embodiment is used for forming a pixel portion of an optical conversion layer included in a color filter or the like by, for example, a photolithography method, an inkjet method, or the like, and is used for forming an optical conversion layer (for example, for a color filter). ) Is the ink composition.

The ink composition of one embodiment can be applied as an ink used in a known and conventional method for manufacturing a color filter, and can be used, for example, by a photolithography method or an inkjet method. Since the ink composition of one embodiment suppresses the increase in viscosity caused by the luminescent nanocrystal particles, it can be suitably used as an inkjet ink. That is, the ink composition of one embodiment is preferably an ink composition for inkjet. When the ink composition is used by the inkjet method, the pixel portion (light conversion) can be used only by using the required amount in the required place without wasting materials such as luminescent nanocrystal particles and organic solvent, which are relatively expensive. Layer) can be formed.

In the following, an ink composition for a color filter (color filter) used in an inkjet method, which contains luminescent nanocrystal particles having an organic ligand on the surface, a photopolymerizable compound and / or a thermosetting resin, and an organic solvent. Ink for use) will be described as an example.

[Luminescent nanocrystal particles]
The luminescent nanocrystal particles are nano-sized crystals that absorb excitation light and emit fluorescence or phosphorescence, and for example, the maximum particle size measured by a transmission electron microscope or a scanning electron microscope is 100 nm or less. It is a crystal.

The luminescent nanocrystal particles can emit light (fluorescence or phosphorescence) having a wavelength different from the absorbed wavelength, for example, by absorbing light having a predetermined wavelength. The luminescent nanocrystal particles may be red luminescent nanocrystal particles (red luminescent nanocrystal particles) that emit light (red light) having an emission peak wavelength in the range of 605 to 665 nm, and may be 500 to 560 nm. It may be green luminescent nanocrystal particles (green luminescent nanocrystal particles) that emit light having an emission peak wavelength in the range (green light), and may be light having an emission peak wavelength in the range of 420 to 480 nm (blue light). ) May be emitted by blue light emitting nanocrystal particles (blue light emitting nanocrystal particles). In this embodiment, it is preferable that the ink composition contains at least one of these luminescent nanocrystal particles. The light absorbed by the luminescent nanocrystal particles is, for example, light having a wavelength in the range of 400 nm or more and less than 500 nm (particularly, light having a wavelength in the range of 420 to 480 nm) (blue light) or light in the range of 200 nm to 400 nm. It may be light of the wavelength of (ultraviolet light). The emission peak wavelength of the luminescent nanocrystal particles can be confirmed, for example, in the fluorescence spectrum or the phosphorescence spectrum measured by using a spectrofluorescence meter.

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

Green luminescent nanocrystal particles have emission peak wavelengths of 560 nm or less, 557 nm or less, 555 nm or less, 550 nm or less, 547 nm or less, 545 nm or less, 543 nm or less, 540 nm or less, 537 nm or less, 535 nm or less, 532 nm or less, or 530 nm or less. It is preferable to have an emission peak 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.

Blue luminescent nanocrystal particles have emission peak wavelengths of 480 nm or less, 477 nm or less, 475 nm or less, 470 nm or less, 467 nm or less, 465 nm or less, 463 nm or less, 460 nm or less, 457 nm or less, 455 nm or less, 452 nm or less, or 450 nm or less. It is preferable to have an emission peak 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.

The wavelength of light emitted by luminescent nanocrystal particles (emission color) depends on the size (for example, particle size) of the luminescent nanocrystal particles according to the solution of the Schrodinger wave equation of the well-type potential model, but the luminescent nanocrystal particles It also depends on the energy gap of the crystal particles. Therefore, the emission color can be selected by changing the constituent material and size of the luminescent nanocrystal particles to be used.

The luminescent nanocrystal particles may be luminescent nanocrystal particles (luminescent semiconductor nanocrystal particles) containing a semiconductor material. Examples of the luminescent semiconductor nanocrystal particles include quantum dots and quantum rods. Among these, quantum dots are preferable from the viewpoints that the emission spectrum can be easily controlled, reliability can be ensured, production cost can be reduced, and mass productivity can be improved.

The luminescent semiconductor nanocrystal particles may consist only of a core containing the first semiconductor material, and include a core containing the first semiconductor material and a second semiconductor material different from the first semiconductor material, as described above. It may have a shell that covers 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). Further, the luminescent semiconductor nanocrystal particles include a third semiconductor material different from the first and second semiconductor materials in addition to the shell (first shell) containing the second semiconductor material, and the above-mentioned core. It may further have a shell (second shell) that covers at least a part of it. In other words, the structure of the luminescent semiconductor nanocrystal particles may be a structure including a core, a first shell, and a second shell (core / shell / shell structure). Each of the core and the shell may be a mixed crystal containing two or more kinds of semiconductor materials (for example, CdSe + CdS, CIS + ZnS, etc.).

The luminescent nanocrystal particles are selected as the semiconductor material from the group consisting of II-VI group semiconductors, III-V group semiconductors, I-III-VI group semiconductors, IV group semiconductors and I-II-IV-VI group semiconductors. It is preferable to contain at least one semiconductor material.

Specific semiconductor materials include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeDZn. CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, CdHgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSeTe, CdHgSeTe, AlHgSte, HgZnS InP, InAs, InSb, PLUP, PLGAs, VMwareSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb; SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSe, PbSn SnPbSTe; Si, Ge, SiC, SiGe, AgInSe ₂ , CuGaSe ₂ , CuInS ₂ , CuGaS ₂ , CuInSe ₂ , AgInS ₂ , AgGaSe ₂ , AgGaS ₂ , C, Si and Ge. The luminescent semiconductor nanocrystal particles have CdS, CdSe, CdTe, ZnS, from the viewpoint that the emission spectrum can be easily controlled, reliability can be ensured, production cost can be reduced, and mass productivity can be improved. ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, InP, InAs, InSb, GaP, GaAs, GaSb, AgInS ₂ , AgInSe ₂ , AgInTe ₂ , AgGaS ₂ , _{AgGaSe 2} , _AgGaS2 , AgGaSe ₂ , _AgGaS2 , CuGaS ₂ , CuGaSe ₂ , CuGaTe ₂ , Si, C, Ge and Cu ₂ ZnSnS ₄ preferably comprises at least one selected from the group.

Examples of the red-emitting semiconductor nanocrystal particles include CdSe nanocrystal particles and nanocrystal particles having a core / shell structure, wherein the shell portion is CdS and the inner core portion is CdSe. Nanocrystal particles having a particle, core / shell structure, the shell portion of which is CdS and the inner core portion of ZnSe, nanocrystal particles of mixed crystals of CdSe and ZnS, and nano of InP. Crystal particles, nanocrystal particles having a core / shell structure, nanocrystal particles having a shell portion of ZnS and an inner core portion of InP, and nanocrystal particles having a core / shell structure. The shell part is a mixed crystal of ZnS and ZnSe and the inner core part is InP nanocrystal particles, the mixed crystal nanocrystal particles of CdSe and CdS, the mixed crystal nanocrystal particles of ZnSe and CdS, and the core. Nanocrystal particles with a / shell / shell structure, the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP. / Nanocrystal particles with a shell structure, 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. And so on.

Examples of the green-emitting semiconductor nanocrystal particles include CdSe nanocrystal particles, mixed-crystal nanocrystal particles of CdSe and ZnS, and nanocrystal particles having a core / shell structure, wherein the shell portion is ZnS. Nanocrystal particles whose inner core is InP, nanocrystal particles having a core / shell structure, whose shell is a mixed crystal of ZnS and ZnSe, and whose inner core is InP. Crystal particles, nanocrystal particles having a core / shell / shell structure, the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP. , Nanocrystal particles with a core / shell / shell structure, 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. Examples include certain nanocrystal particles.

The blue light emitting semiconductor nanocrystal particles include, for example, ZnSe nanocrystal particles, ZnS nanocrystal particles, and nanocrystal particles having a core / shell structure, and the shell portion is ZnSe and the inner core portion. Is ZnS nanocrystal particles, CdS nanocrystal particles, nanocrystal particles having a core / shell structure, and the shell portion is ZnS and the inner core portion is InP nanocrystal particles, core / shell. Nano-crystal particles having a structure, the shell portion is a mixed crystal of ZnS and ZnSe, and the inner core portion is InP. The nano-crystal particles have a core / shell / shell structure. The first shell portion is ZnSe, the second shell portion is ZnS, the inner core portion is InP, and the nanocrystal particles have a core / shell / shell structure. Examples thereof include nano-crystal 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.

The semiconductor nanocrystal particles have the same chemical composition, and by changing the average particle size of the particles themselves, the color to be emitted from the particles can be changed to red or green. Further, it is preferable to use semiconductor nanocrystal particles as such, which have as little adverse effect on the human body as possible. When semiconductor nanocrystal particles containing cadmium, selenium, etc. are used as luminescent nanocrystal particles, semiconductor nanocrystal particles containing the above elements (cadmium, selenium, etc.) as little as possible are selected and used alone, or the above elements. It is preferable to use it in combination with other luminescent nanocrystal particles so that the amount of cadmium is as small as possible.

The shape of the luminescent nanocrystal particles is not particularly limited, and may be any geometric shape or any irregular shape. The shape of the luminescent nanocrystal particles may be, for example, spherical, ellipsoidal, pyramidal, disc-like, branch-like, net-like, rod-like, or the like. However, as the luminescent nanocrystal particles, using particles having less directionality as the particle shape (for example, particles having a spherical shape, a regular tetrahedron shape, etc.) can further improve the uniformity and fluidity of the ink composition. Is preferable.

The average particle diameter (volume average diameter) of the luminescent nanocrystal particles may be 1 nm or more, and may be 1.5 nm, from the viewpoint of easily obtaining light emission of a desired wavelength and from the viewpoint of excellent dispersibility and storage stability. It may be more than 2 nm and may be 2 nm or more. From the viewpoint that a desired emission wavelength can be easily obtained, 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 nanocrystal particles is obtained by measuring with a transmission electron microscope or a scanning electron microscope and calculating the volume average diameter.

Luminescent nanocrystal particles have an organic ligand on their surface from the viewpoint of dispersion stability. The organic ligand may be coordinate-bonded to, for example, the surface of the luminescent nanocrystal particles. In other words, the surface of the luminescent nanocrystal particles may be passivated by an organic ligand.

The organic ligand is a compound having one or more functional groups (functional groups for ensuring the adsorptivity to the luminescent nanocrystal particles) that can be bound to the luminescent nanocrystal particles. In the present embodiment, as the organic ligand, a compound containing one or more functional groups capable of binding to luminescent nanocrystal particles and a polyoxyalkylene group (hereinafter, also referred to as “compound A”) is used. .. As the organic ligand (Compound A), one kind of compound may be used alone, or two or more kinds of compounds may be used in combination.

The polyoxyalkylene group is a divalent group in which two or more alkylene groups are linked by an ether bond, and has a plurality of oxyalkylene structures (oxyalkylene groups). The plurality of alkylene groups constituting the polyoxyalkylene group may be the same as or different from each other. The alkylene group may be linear and may have a branched structure. Further, the alkylene group may have an unsaturated bond or may not have an unsaturated bond.

The carbon number of the alkylene group may be, for example, 1 or more, 2 or more, or 3 or more, and may be 5 or less, 4 or less, or 3 or less. The alkylene group is preferably an ethylene group, a propylene group or a butylene group. That is, the polyoxyalkylene group preferably has an oxyalkylene structure having an ethylene group (oxyethylene structure), an oxyalkylene structure having a propylene group (oxypropylene structure), and an oxyalkylene structure having a butylene group (oxybutylene structure). ) Have at least one selected from the group consisting of.

The polyoxyalkylene group preferably has an oxyalkylene structure represented by the following formula (1).

In formula (1), R ¹ and R ² independently represent a hydrogen atom, a methyl group or an ethyl group, and * indicates a bond. When one of R ¹ and R ² is a methyl group or an ethyl group, the other is preferably a hydrogen atom. R ¹ and R ² are preferably hydrogen atoms or methyl groups. Among them, an oxyethylene structure in which R ¹ and R ² are hydrogen atoms, or an oxypropylene structure in which one of R ¹ and R ² is a methyl group and the other is a hydrogen atom is more preferable.

When the polyoxyalkylene group has a plurality of structures represented by the formula (1), the plurality of R ^1s may be the same or different, and the plurality of R ^2s may be the same or different. ..

The degree of polymerization of the polyoxyalkylene group may be, for example, 4 or more, 10 or more or 20 or more, and may be 50 or less, 40 or less or 30 or less. Here, the degree of polymerization of the polyoxyalkylene group means the number of repetitions of the oxyalkylene structure (the number of alkylene groups linked by an ether bond).

When the polyoxyalkylene group contains a repetition of an oxyethylene structure, the number of repetitions of the oxyethylene structure may be 1 or more, 10 or more or 15 or more, and may be 50 or less or 20 or less.

When the polyoxyalkylene group contains repetitions of the oxypropylene structure, the number of repetitions of the oxypropylene structure may be 1 or more or 2 or more, and may be 10 or less or 5 or less.

The polyoxyalkylene group may be contained in the main chain of the organic ligand (Compound A). Here, the main chain means the longest molecular chain constituting the organic ligand (Compound A).

The functional group that can be bonded to the luminescent nanocrystal particles is, for example, a group that can be coordinate-bonded to the luminescent nanocrystal particles. Examples of the functional group that can be bonded to the luminescent nanocrystal particle include a hydroxyl group, an amino group, a carboxyl group, a thiol group, a phosphoric acid group, a phosphonic acid group, a phosphine group, a phosphine oxide group and an alkoxysilyl group. These functional groups may be bonded to the luminescent nanocrystal particles by a coordination bond or the like. That is, at least one of the functional groups capable of binding to the luminescent nanocrystal particles in the organic ligand on the surface of the luminescent nanocrystal particles may be a functional group bonded to the luminescent nanocrystal particles. When the organic ligand (Compound A) contains a plurality of these functional groups, some of the plurality of functional groups may not be bound to the organic ligand.

The functional group capable of binding to the luminescent nanocrystal particles may be present at at least one end of the main chain of the organic ligand (compound A). That is, the organic ligand (Compound A) may contain a functional group capable of binding to luminescent nanocrystal particles at at least one end of the main chain.

The organic ligand may have a hydrogen bonding group. Here, the hydrogen-bonding functional group means a group having a hydrogen atom capable of forming a hydrogen bond with a carbonyl group or the like. The hydrogen-bonding group may be a group capable of binding to luminescent nanocrystal particles. The organic ligand present on the surface of the luminescent nanocrystal particles preferably has a hydrogen-bonding group that is not bound to the luminescent nanocrystal particles. Examples of the hydrogen-bonding group include a monovalent group such as a hydroxyl group, an amino group, a carboxyl group and a thiol group, and a divalent group such as an amide group (-NHCO-).

The organic ligand (Compound A) has one or more first functional groups capable of binding to luminescent nanocrystal particles at one end of the main chain, and is different from the first functional group at the other end of the main chain. It may have a second functional group. The first functional group may be the same as the group described above as a functional group capable of binding to the luminescent nanocrystal particles. The number of the first functional groups may be 1 or more, 2 or more, and 2 may be. The second functional group may be the same as the above-mentioned group as a functional group capable of binding to the luminescent nanocrystal particles, and may be another group different from the functional group. The other group may be, for example, an alkyl group, a cycloalkyl group, or an aryl group. The number of the second functional group may be 1 or more and may be 1.

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

The backbone may have, for example, a substituted or unsubstituted hydrocarbon group in addition to the polyoxyalkylene group. The substituted or unsubstituted hydrocarbon group may have, for example, 1 to 10 carbon atoms. As the substituted hydrocarbon group, a part of the carbon atom may be substituted with a hetero atom such as a sulfur atom or a nitrogen atom, a carbonyl group or the like.

In one embodiment, the organic ligand (Compound A) may be a compound represented by the following formula (1-1).

In equation (1-1), p indicates an integer of 0 to 50, and q indicates an integer of 0 to 50. It is preferable that at least one of p and q is 1 or more, and it is more preferable that both p and q are 1 or more.

The organic ligand (Compound A) may be, for example, a compound represented by the following formula (1-2).

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

The organic ligand (Compound A) may be, for example, a compound represented by the following formula (1-2A).

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

The ink composition may contain a compound other than the compound A as an organic ligand. The content of compound A may be, for example, 90% by mass or more, 95% by mass or more, 98% by mass or more, or 100% by mass, based on the total amount of the organic ligand.

The weight average molecular weight of the organic ligand is preferably 350 from the viewpoint that good adsorptivity to luminescent nanocrystal particles can be obtained, it is difficult to desorb from the luminescent nanocrystal particles, and the dispersion stability of the particles can be maintained. The above is more preferably 500 or more, still more preferably 700 or more. The weight average molecular weight of the organic ligand may be 1500 or less, or 1000 or less, from the viewpoint of easily keeping the viscosity of the ink composition low. In the present specification, the weight average molecular weight is a polystyrene-equivalent weight average molecular weight measured by GPC (Gel Permeation Chromatography).

The content of the organic ligand in the ink composition is 15 parts by mass or more and 20 parts by mass with respect to 100 parts by mass of the luminescent nanocrystal particles from the viewpoint of dispersion stability of the luminescent nanocrystal particles and maintenance of luminescence characteristics. As mentioned above, it may be 25 parts by mass or more, 30 parts by mass or more, 35 parts by mass or more, or 40 parts by mass or more. The content of the organic ligand in the ink composition is 50 parts by mass or less, 45 parts by mass or less, 40 parts by mass or less, or 40 parts by mass or less with respect to 100 parts by mass of the luminescent nanocrystal particles from the viewpoint of easily keeping the viscosity of the ink composition low. It may be 30 parts by mass or less.

When the ink composition further contains a polymer dispersant described later, the luminescent nanocrystal particles may have a polymer dispersant on the surface thereof. In the present embodiment, for example, a part of the organic ligand is removed from the luminescent nanoparticles having the above-mentioned organic ligand, and the organic ligand is exchanged with the polymer dispersant to increase the surface of the luminescent nanoparticles. A molecular dispersant may be attached. However, from the viewpoint of dispersion stability when the ink jet ink is used, it is preferable that the polymer dispersant is blended with the luminescent nanocrystal particles in which the organic ligand is coordinated.

As the luminescent nanocrystal particles, those dispersed in a colloidal form in an organic solvent, a photopolymerizable compound, or the like can be used. The surface of the luminescent nanocrystal particles dispersed in the organic solvent is preferably passivated by the above-mentioned organic ligand. As the organic solvent, for example, the organic solvent described later contained in the ink composition is used.

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

The content of the luminescent nanocrystal particles may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the mass of the solid content of the ink composition, from the viewpoint of excellent external quantum efficiency. It may be 20% by mass or more, 20% by mass or more, or 30% by mass or more. When the content of the luminescent nanocrystal particles is 5% by mass or more, excellent luminescence intensity can be obtained, so that such an ink composition is suitably used for color filter applications. From the same viewpoint, the content of the luminescent nanocrystal particles may be 80% by mass or less, 75% by mass or less, or 70% by mass or less, based on the mass of the solid content of the ink composition. It may be 60% by mass or less. The content of the luminescent nanocrystal particles is 80% by mass or less based on the mass of the solid content of the ink composition from the viewpoint of being more excellent in ejection stability. Further, when the content of the luminescent nanocrystal particles is 80% by mass or less, excellent luminescence intensity can be obtained, so such an ink composition is suitably used as an inkjet ink for a color filter. The content of the luminescent nanocrystal particles is 5 to 80% by mass, 10 to 80% by mass, 15 to 80% by mass, 10 to 60% by mass, and 15 to 60% by mass based on the mass of the solid content of the ink composition. %, 20-60% by mass or 30-60% by mass. In the present specification, the "mass of the solid content of the ink composition" means the mass obtained by subtracting the mass of the solvent from the total mass of the ink composition.

The concentration (content) of the luminescent nanocrystal particles is 10% by mass or more, 15% by mass or more, 18% by mass or more, 20% by mass or more, or 25% by mass or more, based on the total mass of the ink composition. There may be. In this embodiment, since the above-mentioned specific organic ligand and the specific organic solvent described later are used, it is good even when the concentration (content) of the luminescent nanocrystal particles is 25% by mass or more. Discharge stability is easy to obtain. The concentration (content) of the luminescent nanocrystal 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 ink composition.

The ink composition may contain two or more of the red luminescent nanocrystal particles, the green luminescent nanocrystal particles, and the blue luminescent nanocrystal particles as the luminescent nanocrystal particles, but these are preferable. Contains only one of the particles. When the ink composition contains red luminescent nanocrystal particles, the content of the green luminescent nanocrystal particles and the content of the blue luminescent nanocrystal particles are preferably 10 based on the total mass of the luminescent nanocrystal particles. It is 0% by mass or less, more preferably 0% by mass. When the ink composition contains green luminescent nanocrystal particles, the content of the red luminescent nanocrystal particles and the content of the blue luminescent nanocrystal particles are preferably 10 based on the total mass of the luminescent nanocrystal particles. It is 0% by mass or less, more preferably 0% by mass.

[Organic solvent]
The organic solvent is a compound that does not contain a functional group that can bind to the luminescent nanocrystal particles in the above-mentioned organic ligand, and is, for example, a low molecular weight compound having a molecular weight of 300 or less. The ink composition of the embodiment contains, as an organic solvent, a compound containing a polyoxyalkylene group and not containing an ester group (hereinafter, also referred to as “Compound B”). Here, the ester group is a divalent group represented by -COO-, and is also called an ester bond. In the present specification, the ester bond contained in the cyclic ester is also regarded as the above ester group. As the organic solvent (Compound B), one kind of compound may be used alone, or two or more kinds of compounds may be used in combination.

The polyoxyalkylene group contained in the organic solvent (compound B) has the same oxyalkylene structure as that of the polyoxyalkylene group contained in the organic ligand (compound A) described above. That is, when the organic ligand (Compound A) has an oxyalkylene structure represented by the above formula (1), the organic solvent (Compound B) also has an oxyalkylene structure represented by the above formula (1). The polyoxyalkylene group contained in the organic solvent (compound B) may have an oxyalkylene structure not contained in the organic ligand (compound A), and may be derived only from the oxyalkylene structure contained in the organic ligand (compound A). It may be.

When the organic solvent (Compound B) contains a polyoxyalkylene group having a structure represented by the formula (1), the polyoxyalkylene group may have a plurality of structures represented by the formula (1). In this case, the plurality of R ^1s may be the same or different.

The degree of polymerization of the polyoxyalkylene group contained in the organic solvent (compound B) is preferably 2 or more, and may be 3 or more, from the viewpoint of boiling point and vapor pressure. The degree of polymerization of the polyoxyalkylene group contained in the organic solvent (compound B) is preferably 4 or less, and may be 3 or less, from the viewpoint of boiling point and vapor pressure.

When the polyoxyalkylene group contains repetitions of the oxyethylene structure, the number of repetitions of the oxyethylene structure may be 1 or more or 2 or more, and may be 3 or less or 2 or less.

When the polyoxyalkylene group contains repetitions of the oxypropylene structure, the number of repetitions of the oxypropylene structure may be 1 or more or 2 or more, and may be 3 or less or 2 or less.

The polyoxyalkylene group may be contained in the main chain of the organic solvent (Compound B). Here, the main chain means the longest molecular chain constituting the organic solvent (compound B).

At least one end of the main chain of the organic solvent (Compound B) may be an alkyl group having 1 to 4 carbon atoms. That is, it may have an alkyl group having 1 to 4 carbon atoms at at least one end of the main chain of the organic solvent (compound B). Preferably, both ends of the main chain of the organic solvent (Compound B) are alkyl groups having 1 to 4 carbon atoms. In this case, the viscosity increase rate tends to be further reduced. The alkyl group present at at least one end of the main chain of the organic solvent (Compound B) may be linear or may have a branched structure. The alkyl group is preferably a methyl group or an ethyl group. The alkyl group may be attached to the end of the main chain by an ether bond. That is, at least one end of the main chain may be an alkoxy group having 1 to 4 carbon atoms.

The organic solvent (compound B) is preferably a compound represented by the following formula (2).

In equation (2), R ¹ and R ² are synonymous with R ¹ and R ² in equation (1). R ³ and R ⁴ each independently represent the above-mentioned alkyl group having 1 to 4 carbon atoms, and n represents an integer of 2 to 4 carbon atoms. The plurality of R ^1s may be the same or different, and the plurality of R ^2s may be the same or different. When one of R ¹ and R ² is a methyl group or an ethyl group, the other is preferably a hydrogen atom. R ¹ and R ² are preferably hydrogen atoms or methyl groups.

Specific examples of the organic solvent (compound B) include dipropylene glycol dimethyl ether (DMM), diethylene glycol diethyl ether (DEEE), diethylene glycol butylmethyl ether (DEBM) and the like.

The ink composition may contain a compound other than the compound B as the organic solvent. The content of the compound B may be 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass, based on the total amount of the organic solvent.

The molecular weight of the organic solvent is, for example, 100 or more, 150 or more or 170 or more, and 300 or less, 250 or less or 200 or less.

The viscosity of the organic solvent is preferably 2.0 mPa · s or less, more preferably 1.8 mPa · s or less, from the viewpoint of easily reducing the viscosity of the ink composition and further increasing the concentration of the luminescent nanocrystal particles. It is more preferably 1.6 mPa · s or less. The viscosity of the organic solvent may be 1.0 mPa · s or more from the viewpoint of easily preventing dripping of the ink at the time of ejection due to the viscosity of the ink composition becoming too low. The viscosity of the organic solvent is the viscosity at 25 ° C. The viscosity of the organic solvent is measured, for example, by an E-type viscometer.

The boiling point of the organic 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 it is necessary to remove the organic solvent from the ink composition before curing the ink composition at the time of forming the pixel portion, the boiling point of the organic solvent is preferably 300 ° C. or lower from the viewpoint of easy removal of the organic solvent. .. The boiling point of the organic solvent is the boiling point at 1 atm.

The vapor pressure of the organic solvent at 25 ° C. is preferably 133 Pa (1 Torr) or less from the viewpoint of continuous ejection stability of the inkjet ink and from the viewpoint of easy ejection again after stopping ejection (from the viewpoint of re-ejection property). , More preferably 100 Pa (0.75 Torr) or less. The vapor pressure of the organic solvent at 25 ° C. may be 10 Pa (0.075 Torr) or more from the viewpoint of easy removal of the solvent after forming the pixel portion.

The content of the organic solvent in the ink composition is 65% by mass or less and 60% by mass or less based on the total mass of the ink composition from the viewpoint of increasing the thickness of the pixel portion that can be formed by one ejection. Alternatively, it may be 50% by mass or less. In other words, the solid content concentration of the ink composition may be 35% by mass or more, 40% by mass or more, or 50% by mass or more. The lower limit of the content of the organic solvent in the ink composition may be adjusted so that the viscosity of the ink composition becomes a desired viscosity. The content of the organic solvent may be, for example, 20% by mass or more based on the total mass of the ink composition. In other words, the solid content concentration of the ink composition may be 80% by mass or less. Here, the solid content concentration means the concentration (content) of a component other than the solvent in the ink composition.

[Photopolymerizable compound]
The photopolymerizable compound of the present embodiment is a compound that polymerizes by irradiation with light, and is, for example, a photoradical polymerizable compound or a photocationic polymerizable compound. The photopolymerizable compound may be a photopolymerizable monomer or oligomer. These are used with photopolymerization initiators. The photoradical polymerizable compound is used together with the photoradical polymerization initiator, and the photocationic polymerizable compound is used together with the photocationic polymerization initiator. In other words, the ink composition may contain a photopolymerizable component containing a photopolymerizable compound and a photopolymerization initiator, and may contain a photoradical polymerizable component containing a photoradical polymerizable compound and a photoradical polymerization initiator. It may contain a photocationic polymerizable component including a photocationic polymerizable compound and a photocationic polymerization initiator. A photoradical polymerizable compound and a photocationic polymerizable compound may be used in combination, or a compound having photoradical polymerizable property and photocationic polymerizable property may be used, and a photoradical polymerization initiator and a photocationic polymerization initiator may be used. May be used together. One type of photopolymerizable compound may be used alone, or two or more types may be used in combination.

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

The number of ethylenically unsaturated bonds (for example, the number of ethylenically unsaturated groups) in the ethylenically unsaturated monomer is, for example, 1 to 3. One type of ethylenically unsaturated monomer may be used alone, or a plurality of types may be used in combination. The photopolymerizable compound has one or two ethylenically unsaturated groups from the viewpoint of facilitating both excellent ejection stability and excellent curability, and from the viewpoint of further improving the external quantum efficiency. It may contain a monomer and a monomer having two or three ethylenically unsaturated groups. That is, the ethylenically unsaturated monomer is selected from at least a group consisting of a monofunctional monomer and a bifunctional monomer, a monofunctional monomer and a trifunctional monomer, a bifunctional monomer and a bifunctional monomer, and a bifunctional monomer and a trifunctional monomer. It may contain one combination. In the present embodiment, it is preferable that the photopolymerizable compound contains two or more kinds of monomers having two ethylenically unsaturated bonds.

Examples of the ethylenically unsaturated group include a vinyl group, a vinylene group, a vinylidene group, and a (meth) acryloyl group. In addition, in this specification, "(meth) acryloyl group" means "acryloyl group" and the corresponding "methacryloyl group". The same applies to the expressions "(meth) acrylate" and "(meth) acrylamide".

Examples of the monofunctional monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and octyl (meth). Acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) ) Acrylate, nonylphenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (Meta) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl ( Meta) acrylate, benzyl (meth) acrylate, phenylbenzyl (meth) acrylate, mono (2-acryloyloxyethyl) arsenic, N- [2- (acryloyloxy) ethyl] phthalimide, N- [2- (acryloyloxy) Ethyl] Tetrahydrophthalimide and the like can be mentioned. Among these, ethoxyethoxyethyl (meth) acrylate is preferably used.

Specific examples of the monomer having two ethylenically unsaturated groups (bifunctional monomer) include 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,5-pentane. Didioldi (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 ) Acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentylglycol hydroxypivalic acid ester diacrylate, tris (2-hydroxyethyl) ) Di (meth) acrylate in which the two hydroxyl groups of isocyanurate are substituted with a (meth) acryloyloxy group, and two diols obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol. The two hydroxyl groups of the diol obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of di (meth) acrylate and bisphenol A in which the hydroxyl groups of the above are substituted with (meth) acryloyloxy groups are (meth) acryloyloxy groups. Di (meth) acrylate substituted with (meth) Acryloyloxy group The two hydroxyl groups of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane are substituted with (meth) acryloyloxy group. Examples thereof include meth) acrylates and di (meth) acrylates in which two hydroxyl groups of a diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A are substituted with (meth) acryloyloxy groups. Among these, dipropylene glycol di (meth) acrylate is preferably used.

Specific examples of the monomer having three ethylenically unsaturated groups (trifunctional monomer) include glycerintri (meth) acrylate and trimethylolethanetri (meth) acrylate. Among these, glycerin tri (meth) acrylate is preferably used.

Examples of the photocationically polymerizable compound include an epoxy compound, an oxetane compound, a vinyl ether compound and the like.

Examples of the epoxy compound include aliphatic epoxy compounds such as bisphenol A type epoxy compound, bisphenol F type epoxy compound, phenol novolac type epoxy compound, trimethylolpropane polyglycidyl ether, and neopentyl glycol diglycidyl ether, 1,2-epoxy-. Examples thereof include alicyclic epoxy compounds such as 4-vinylcyclohexane and 1-methyl-4- (2-methyloxylanyl) -7-oxabicyclo [4.1.0] heptane.

It is also possible to use a commercially available product as the epoxy compound. As a commercially available epoxy compound, for example, "Selokiside 2000", "Selokiside 3000", "Selokiside 4000", etc. manufactured by Daicel Chemical Industries, Ltd. can be used.

Cationicly polymerizable oxetane compounds include 2-ethylhexyl oxetane, 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-propyloxetane, and 3-hydroxymethyl-3. -Normal butyl oxetane, 3-hydroxymethyl-3-phenyloxetane, 3-hydroxymethyl-3-benzyloxetane, 3-hydroxyethyl-3-methyloxetane, 3-hydroxyethyl-3-ethyloxetane, 3-hydroxyethyl- 3-propyl oxetane, 3-hydroxyethyl-3-phenyloxetane, 3-hydroxypropyl-3-methyloxetane, 3-hydroxypropyl-3-ethyloxetane, 3-hydroxypropyl-3-propyloxetane, 3-hydroxypropyl- Examples thereof include 3-phenyloxetane and 3-hydroxybutyl-3-methyloxetane.

It is also possible to use a commercially available product as an oxetane compound. Examples of commercially available oxetane compounds include Aron oxetane series manufactured by Toa Synthetic Co., Ltd. (“OXT-101”, “OXT-212”, “OXT-121”, “OXT-221”, etc.); Company-made "Selokiside 2021", "Selokiside 2021A", "Selokiside 2021P", "Selokiside 2080", "Selokiside 2081", "Selokiside 2083", "Selokiside 2085", "Epolide GT300", "Epolide GT301", "Eporide" GT302, "Epolide GT400", "Epolide GT401" and "Epolide GT403"; "Cyracure UVR-6105", "Cyracure UVR-6107", "Cyracure UVR-6110", "Cyracure UVR" manufactured by Dow Chemical Japan Co., Ltd. -6128 "," ERL4289 "," ERL4299 "and the like can be used. Further, a known oxetane compound (for example, the oxetane compound described in JP-A-2009-40830) can also be used.

Examples of the vinyl ether compound include 2-hydroxyethyl vinyl ether, triethylene glycol vinyl monoether, tetraethylene glycol divinyl ether, and trimethylolpropane trivinyl ether.

Further, as the photopolymerizable compound in the present embodiment, the photopolymerizable compounds described in paragraphs 0042 to 0049 of JP2013-182215A can also be used.

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

The content of the photopolymerizable compound is from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, from the viewpoint of improving the curability of the ink composition, and the solvent resistance of the pixel portion (cured product of the ink composition). From the viewpoint of improving the wear resistance, it may be 10% by mass or more, 15% by mass or more, or 20% by mass or more based on the mass of the solid content of the ink composition. The content of the photopolymerizable compound is the solid content of the ink composition from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink and from the viewpoint of obtaining more excellent optical characteristics (for example, the effect of suppressing a decrease in external quantum efficiency). It may be 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 There may be.

[Photopolymerization initiator]
The photopolymerization initiator is, for example, a photoradical polymerization initiator. As the photoradical polymerization initiator, a molecular cleavage type or hydrogen abstraction type photoradical polymerization initiator is suitable.

Examples of the molecular cleavage type photoradical polymerization initiator include benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2-benzyl-2-dimethylamino-1. -(4-Morphorinophenyl) -butane-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 photoradical polymerization 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-methylpropane-1-one and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one may be used in combination.

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

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

The content of the photopolymerization initiator may be 0.1 part by mass or more and 0.5 part by mass or more with respect to 100 parts by mass of the photopolymerizable compound from the viewpoint of curability of the ink composition. 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, and 30 parts by mass with respect to 100 parts by mass of the photopolymerizable compound, from the viewpoint of stability over time of the pixel portion (cured product of the ink composition). It may be 20 parts by mass or less, 10 parts by mass or less, or 10 parts by mass or less.

[Thermosetting resin]
In the present embodiment, the thermosetting resin is a resin that is crosslinked and cured by heat. The thermosetting resin is, for example, a resin that functions as a binder in a cured product. Thermosetting resins have curable groups. Examples of the curable group include an epoxy group, an oxetane group, an isocyanate group, an amino group, a carboxyl group, a methylol group, etc. For example, an epoxy group is preferable from the viewpoint of excellent adhesion to a black matrix) and a substrate. The thermosetting resin may have one kind of curable group or may have two or more kinds of curable groups.

Among the thermosetting resins, a resin having photoradical polymerizable property (polymerized by irradiation with light when used together with a photoradical polymerization initiator) and a photocationic polymerizable resin (photocationic polymerization). Contains resins (polymerized by light irradiation when used with initiators). When the ink composition contains a thermocurable resin having photoradical polymerizable property and a photoradical polymerization initiator, the thermocurable resin having photoradical polymerizable property becomes a photoradical polymerizable compound (photopolymerizable compound). It shall be classified. When the ink composition contains a photocationically polymerizable thermosetting resin and a photocationic polymerization initiator, the photocationically polymerizable thermosetting resin becomes a photocationically polymerizable compound (photopolymerizable compound). It shall be classified.

The thermosetting resin may be a polymer (homopolymer) of a single monomer, or may be a copolymer (copolymer) of a plurality of types of monomers. Further, the thermosetting resin may be any of a random copolymer, a block copolymer or a graft copolymer.

As the thermosetting resin, a compound having two or more thermosetting groups in one molecule is used, and it is usually used in combination with a curing agent. When a thermosetting resin is used, a catalyst (curing accelerator) capable of accelerating the thermosetting reaction may be further added. In other words, the ink composition may contain a thermosetting component including a thermosetting resin (as well as a curing agent and a curing accelerator used as needed). In addition to these, a polymer that does not have a polymerization reactivity by itself may be further used.

As the compound having two or more thermosetting groups in one molecule, for example, an epoxy resin having two or more epoxy groups in one molecule (hereinafter, also referred to as “polyfunctional epoxy resin”) may be used. The "epoxy resin" includes both a monomeric epoxy resin and a polymer epoxy resin. The number of epoxy groups contained in one molecule of the polyfunctional epoxy resin is preferably 2 to 50, more preferably 2 to 20. The epoxy group may be any structure as long as it has an oxylan ring structure, and may be, for example, a glycidyl group, an oxyethylene group, an epoxycyclohexyl group, or the like. Examples of the epoxy resin include known polyvalent epoxy resins that can be cured by a carboxylic acid. Such epoxy resins are widely disclosed in, for example, "Epoxy Resin Handbook" edited by Masaki Shinbo, published by Nikkan Kogyo Shimbun (1987), and these can be used.

Examples of the thermosetting resin having an epoxy group (including a polyfunctional epoxy resin) include a polymer of a monomer having an oxylan ring structure and a copolymer of a monomer having an oxylan ring structure and another monomer. Specific examples of the polyfunctional epoxy resin include polyglycidyl methacrylate, methyl methacrylate-glycidyl methacrylate copolymer, benzyl methacrylate-glycidyl methacrylate copolymer, n-butyl methacrylate-glycidyl methacrylate copolymer, and 2-hydroxyethyl methacrylate-glycidyl. Examples thereof include a methacrylate copolymer, a (3-ethyl-3-oxetanyl) methyl methacrylate-glycidyl methacrylate copolymer, and a styrene-glycidyl methacrylate. Further, as the thermosetting resin of the present embodiment, the compounds described in paragraphs 0044 to 0066 of JP-A-2014-56248 can also be used.

Examples of the polyfunctional epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, and naphthalene type epoxy. Resin, biphenyl type epoxy resin, fluorene type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, trishydroxyphenylmethane type epoxy resin, trifunctional epoxy resin, tetraphenylol ethane type epoxy resin, dicyclopentadiene Phenolic type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol A nucleated polyol type epoxy resin, polypropylene glycol type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, glioxal type epoxy resin, alicyclic epoxy resin , A heterocyclic epoxy resin, etc. can be used.

More specifically, a bisphenol A type epoxy resin such as the product name "Epicoat 828" (manufactured by Japan Epoxy Resin), a bisphenol F type epoxy resin such as the product name "YDF-175S" (manufactured by Toto Kasei Co., Ltd.), and a product name. Brominated bisphenol A type epoxy resin such as "YDB-715" (manufactured by Toto Kasei Co., Ltd.), bisphenol S type epoxy resin such as trade name "EPICLON EXA1514" (manufactured by DIC Co., Ltd.), trade name "YDC-1312" (Toto) Hydroquinone type epoxy resin such as (manufactured by Kasei Co., Ltd.), Naphthalene type epoxy resin such as product name "EPICLON EXA4032", "HP-4770", "HP-4700", "HP-5000" (manufactured by DIC Co., Ltd.), product name Biphenyl type epoxy resin such as "Epicoat YX4000H" (manufactured by Japan Epoxy Resin), bisphenol A type novolak epoxy resin such as product name "Epicoat 157S70" (manufactured by Japan Epoxy Resin), product name "Epicoat 154" (Japan Epoxy) Resin company), phenol novolac type epoxy resin such as product name "YDPN-638" (manufactured by Toto Kasei Co., Ltd.), cresol novolac type epoxy resin such as product name "YDCN-701" (manufactured by Toto Kasei company), product name " Dicyclopentadienephenol type epoxy resin such as "EPICLON HP-7200" and "HP-7200H" (manufactured by DIC Co., Ltd.), Trishydroxyphenylmethane type epoxy resin such as trade name "Epicoat 1032H60" (manufactured by Japan Epoxy Resin), Trifunctional epoxy resin such as product name "VG3101M80" (manufactured by Mitsui Kagaku Co., Ltd.), tetraphenylol ethane type epoxy resin such as product name "Epicoat 1031S" (manufactured by Japan Epoxy Resin), product name "Denacol EX-411" 4-functional epoxy resin such as (manufactured by Nagase Kasei Kogyo Co., Ltd.), hydrogenated bisphenol A type epoxy resin such as product name "ST-3000" (manufactured by Toto Kasei Co., Ltd.), product name "Epicoat 190P" (manufactured by Japan Epoxy Resin) ) And other glycidyl ester-type epoxy resins, glycidylamine-type epoxy resins such as the trade name "YH-434" (manufactured by Toto Kasei Co., Ltd.), and glioxal-type epoxy resins such as the trade name "YDG-414" (manufactured by Toto Kasei Co., Ltd.). Triglycidyl isocyanate, an alicyclic polyfunctional epoxy compound such as the product name "Epolide GT-401" (manufactured by Daicel Chemical Co., Ltd.) A heterocyclic epoxy resin such as TGIC) can be exemplified. Further, if necessary, the trade name "Neo Tote E" (manufactured by Toto Kasei Co., Ltd.) or the like can be mixed as the epoxy reactive diluent.

The polyfunctional epoxy resins include "Findick A-247S", "Findick A-254", "Findick A-253", "Findick A-229-30A", and "Fine Dick A-229-30A" manufactured by DIC Corporation. "Dick A-261", "Find Dick A249", "Find Dick A-266", "Find Dick A-241", "Find Dick M-8020", "EPICLON N-740", "EPICLON N-770", " "EPICLON N-865", "EPICLON EXA-4850-150" (trade name) and the like can be used.

The weight average molecular weight of the thermosetting resin is from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, from the viewpoint of improving the curability of the ink composition, and the solvent resistance of the pixel portion (cured product of the ink composition). And from the viewpoint of improving the wear resistance, it may be 750 or more, 1000 or more, or 2000 or more. From the viewpoint of obtaining an appropriate viscosity as an inkjet ink, it may be 500,000 or less, 300,000 or less, or 200,000 or less. However, this does not apply to the molecular weight after cross-linking.

The content of the thermosetting resin is from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, from the viewpoint of improving the curability of the ink composition, and the solvent resistance of the pixel portion (cured product of the ink composition). From the viewpoint of improving wearability, it may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass, based on the mass of the solid content of the ink composition. It may be% or more. The content of the thermosetting resin is based on the mass of the solid content of the ink composition from the viewpoint that the viscosity of the inkjet ink does not become too high and the thickness of the pixel portion does not become too thick for the light conversion function. It may be 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.

[Curing agent]
Examples of the curing agent used for curing the thermosetting resin include acid anhydrides, phenolic compounds, amine-based compounds and the like. These curing agents may be used alone or in combination of two or more. The curing agent preferably contains at least one selected from the group consisting of acid anhydrides, phenolic compounds and amine compounds. When the epoxy resin is used as the thermosetting resin, it may be self-polymerized using onium salts, organic metal complexes, tertiary amines, imidazoles and the like.

Examples of the acid anhydride (acid anhydride-based curing agent) include 4-methylcyclohexane-1,2-dicarboxylic acid anhydride (4M-HHPA), 3-methylcyclohexane-1,2-dicarboxylic acid anhydride, and cyclohexane-1. , 2-Dicarboxylic Acid Anhydride, 1,2,3,6-TetrahydroAnhydrous phthalic acid, 3-Methyl-1,2,3,6-Tetrahydrohydroanhydride, 4-Methyl-1,2,3,6- Tetrahydrophthalic anhydride, bicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride, methylbicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride, methyl-3,6 end Methylene-1,2,3,6-tetrahydrophthalic anhydride, 3,6 endomethylene-1,2,3,6-tetrahydrophthalic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleine anhydride Acids and the like can be mentioned.

Examples of the phenolic compound (phenolic curing agent) include bisphenol A, bisphenol F, bisphenol S, resorcin, catechol, hydroquinone, fluorene bisphenol, 4,4'-biphenol, 4,4', 4 "-trihydroxytriphenylmethane. , Naphthalenediol, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, calixarene, novolak type phenolic resin (eg, phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, bisphenol S novolak resin, resorcin Polyhydric phenol novolak resin synthesized from polyhydric hydroxy compound represented by novolak resin and formaldehyde, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, naphthol novolak resin, and alkoxy group-containing aromatic ring modification. Novolak resin (a polyhydric phenol compound in which a phenol nucleus and an alkoxy group-containing aromatic ring are linked with formaldehyde)), an aralkyl-type phenol resin (for example, a phenol aralkyl resin such as Zyroc resin and a naphthol aralkyl resin), an aromatic hydrocarbon formaldehyde resin. Modified phenol resin, dicyclopentadienephenol-added resin, trimethylolmethane resin, tetraphenylol ethane resin, biphenyl-modified phenol resin (polyvalent phenol compound in which phenol nuclei are linked by bismethylene group), biphenyl-modified naphthol resin (bismethylene group) Polyvalent naphthol compounds linked with phenol nuclei), polyhydric phenol compounds such as aminotriazine-modified phenolic resins (polyhydric phenol compounds linked with phenol nuclei with melamine, benzoguanamine, etc.), etc. From the viewpoint of excellent improvement effect, the phenolic compound preferably contains a novolak-type phenol resin. As the novolak-type phenol resin, phenol novolak resin, cresol novolak resin and bisphenol A novolak resin are preferably used.

Specific examples of the novolak type phenolic resin include "PHENOLITE TD-2131" and "PHENOLITE TD-2090" (trade name) manufactured by DIC Corporation, and "GPH-65" and "GPH-103" manufactured by Nippon Kayaku Corporation. "(Product name) and the like.

Examples of the amine-based compound (amine-based curing agent) include aliphatic polyamines such as ethylenediamine, propylenediamine, butylene diamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, and pentaethylenehexamine, metaxylylene diamine, and diaminodiphenylmethane. Aromatic polyamines such as phenylenediamine, alicyclic polyamines such as 1,3-bis (aminomethyl) cyclohexane, isophoronediamine, norbornandiamine, etc., diamines of dicyandiamide and linolenic acid, and polyamide synthesized from ethylenediamine. Resin is mentioned.

The curing agent is preferably an acid anhydride-based curing agent from the viewpoint of heat resistance of the external quantum efficiency of the cured product of the ink composition, and from the viewpoint of the curing property of the cured product of the ink composition and the viscosity stability of the ink composition. Therefore, a phenolic curing agent is desirable.

The content of the curing agent may be, for example, 40% by mass or less, 30% by mass or less, or 20% by mass or less, based on the mass of the solid content of the ink composition. It may be 10% by mass or less. The content of the curing agent may be, for example, 1% by mass or more, or 3% by mass or more, based on the mass of the solid content of the ink composition.

[Curing accelerator (curing catalyst)]
Examples of the curing accelerator (curing catalyst) used for curing the thermosetting resin include phosphorus compounds, tertiary amine compounds, imidazole compounds, organic acid metal salts, Lewis acids, amine complex salts and the like. .. Examples of the phosphorus-based compound include triphenylphosphine, triparatrilphosphine, diphenylcyclohexylphosphine, and methyltributylphosphonium iodide. Examples of the tertiary amine compound include N, N-dimethylbenzylamine, 1,8-diazabicyclo (5,4,0) undecene-7, 1,5-diazabicyclo (4,3,0) nonene-5, and tris. Examples include (dimethylaminomethyl) phenol. Examples of the imidazole compound include 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole.

The thermosetting resin may be alkali-insoluble from the viewpoint that a highly reliable pixel portion (cured product of the ink composition) can be easily obtained. When the thermosetting resin is alkali-insoluble, the amount of the thermosetting resin dissolved at 25 ° C. in 1% by mass of the potassium hydroxide aqueous solution is 30% by mass or less based on the total mass of the thermosetting resin. Means that. The dissolved amount of the thermosetting resin is preferably 10% by mass or less, and more preferably 3% by mass or less.

In the present embodiment, the ink composition may contain at least one of a photopolymerizable compound and a thermosetting resin, and may contain both a photopolymerizable compound and a thermosetting resin. .. When the ink composition contains a photopolymerizable compound, it does not have to contain a thermosetting resin. Further, when the ink composition contains a thermosetting resin, it does not have to contain a photopolymerizable compound. A photopolymerizable compound from the viewpoint of storage stability of an ink composition containing luminescent nanocrystal particles (for example, quantum dots) and durability (wet heat stability, etc.) of a pixel portion (cured product of the ink composition). Of the heat-curable resins, it is preferable to use a heat-curable resin, and the storage stability of the ink composition containing luminescent nanocrystal particles (for example, quantum dots) and the low temperature which is not easily deteriorated by heating of the quantum dots. It is more preferable to use a photoradical polymerizable compound from the viewpoint of enabling curing in It is preferable to use a sex compound.

When the ink composition contains a photopolymerizable compound and a thermosetting resin, the total content of the photopolymerizable compound and the thermosetting resin is the viewpoint that an appropriate viscosity for an inkjet ink can be easily obtained, and the ink composition is cured. From the viewpoint of improving the properties and improving the solvent resistance and abrasion resistance of the pixel portion (cured product of the ink composition), the content is 3% by mass or more based on the mass of the solid content of the ink composition. It may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more. Further, the total content of the photopolymerizable compound and the thermosetting resin is an ink composition from the viewpoint that the viscosity of the inkjet ink does not become too high and the thickness of the pixel portion does not become too thick for the light conversion function. It may be 60% by mass or less, 40% by mass or less, or 20% by mass or less based on the mass of the solid content of.

The ink composition may further contain components other than the above-mentioned components as long as the effects of the present invention are not impaired. Examples of other components include light-scattering particles, polymer dispersants, and the like.

[Light scattering particles]
The light-scattering particles are, for example, optically inert inorganic particles. When the ink composition contains light-scattering particles, the light from the light source irradiated to the pixel portion can be scattered, so that excellent optical characteristics 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, etc. 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, Metallic carbonates such as secondary bismuth carbonate 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 hyponitrate Such as metal salts and the like. The light-scattering particles are from the group consisting of titanium oxide, alumina, zinc oxide, zinc oxide, calcium carbonate, barium sulfate, barium titanate, and silica from the viewpoint of excellent ejection stability and the effect of improving external quantum efficiency. It is preferable to contain at least one selected, and more preferably to contain at least one selected from the group consisting of titanium oxide, zinc oxide, zinc oxide and barium titanate.

The shape of the light-scattering particles may be spherical, filamentous, indefinite, or the like. However, as the light-scattering particles, it is possible to use particles having less directional particle shape (for example, particles having a spherical shape, a regular tetrahedron shape, etc.) to improve the uniformity, fluidity, and light scattering property of the ink composition. It is preferable in that it can be enhanced and excellent ejection stability can be obtained.

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 the effect of improving 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 present, and 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 It may be 0.0 μm, 0.2 to 0.6 μm, 0.2 to 0.4 μm, 0.3 to 1.0 μm, 0.3 to 0.6 μm, or 0.3 to 0.4 μm. From the viewpoint that such an average particle diameter (volume average diameter) can be easily obtained, the average particle diameter (volume average diameter) of the light-scattering particles used may be 0.05 μm or more, and may be 1.0 μm or less. You may. In the present 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. .. Further, the average particle diameter (volume average diameter) of the light-scattering particles to be used can be obtained by measuring the particle diameter of each particle with, for example, a transmission electron microscope or a scanning electron microscope, and calculating the volume average diameter.

The content of the light-scattering particles in the ink composition may be 0.1% by mass or more based on the mass of the solid content of the ink composition from the viewpoint of being more excellent in the effect of improving the external quantum efficiency, and may be 1% by mass. It may be 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, and 50% by mass, based on the mass of the solid content of the ink composition from the viewpoint of excellent ejection stability and the effect of improving 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, 15% by mass. It may be less than or equal to%. When the ink composition contains a polymer dispersant, the light-scattering particles can be satisfactorily dispersed even when the content of the light-scattering particles is relatively large (for example, when the content is about 60% by mass). can.

The mass ratio of the content of the light-scattering particles to the content of the luminescent nanocrystal particles (light-scattering particles / luminescent nanocrystal particles) is 0.1 or more from the viewpoint of excellent effect of improving the external quantum efficiency. It may be 0.2 or more, or 0.5 or more. The mass ratio (light-scattering particles / luminescent nanocrystal particles) may be 5.0 or less from the viewpoint of excellent effect of improving external quantum efficiency and excellent continuous ejection property (ejection stability) during inkjet printing. , 2.0 or less, or 1.5 or less.

The content of the inorganic component in the ink composition (for example, the total amount of the luminescent nanocrystal particles and the light-scattering particles) is the mass of the solid content of the ink composition from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink. As a reference, it is preferably 30% by mass or more, more preferably 50% by mass or more, and further preferably 65% by mass or more. The content of the inorganic component in the ink composition (for example, the total amount of the luminescent nanocrystal particles and the light-scattering particles) is the mass of the solid content of the ink composition from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink. As a reference, it is preferably 85% by mass or less, more preferably 80% by mass or more, and further preferably 75% by mass or less. The content of the inorganic component in the ink composition (for example, the total amount of the luminescent nanocrystal particles and the light scattering particles) may be 30 to 85% by mass, 50 to 80% by mass, or 65 to 75% by mass. ..

[Polymer dispersant]
The polymer dispersant is a polymer 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 light-scattering particles. The polymer dispersant is adsorbed on the light-scattering particles via a functional group having an affinity for the light-scattering particles, and the light-scattering particles are generated by electrostatic repulsion and / or steric repulsion between the polymer dispersants. Disperse in the ink composition. The polymer dispersant is preferably bonded to the surface of the light-scattering particles and adsorbed to the light-scattering particles, but is bonded to the surface of the luminescent nanoparticles and adsorbed to the luminescent nanoparticles. It may be free in the ink composition.

Examples of the functional group having an affinity for light-scattering particles include an acidic functional group, a basic functional group and a nonionic functional group. The acidic functional group has a dissociative proton and may be neutralized by a base such as an amine or a hydroxide ion, and the basic functional group is neutralized by an acid such as an organic acid or an inorganic acid. May be.

The acidic functional groups include a carboxyl group (-COOH), a sulfo group (-SO ₃ H), a sulfate group (-OSO ₃ H), a phosphonic acid group (-PO (OH) ₃ ), and a phosphate group (-OPO (-OPO)). OH) ₃ ), phosphinic acid group (-PO (OH)-), mercapto group (-SH), and the like.

Examples of the basic functional group include primary, secondary and tertiary amino groups, ammonium groups, imino groups, and nitrogen-containing heterocyclic groups such as pyridine, pyrimidine, pyrazine, imidazole, and triazole.

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

The polymer dispersant may be a polymer (homopolymer) of a single monomer, or may be a copolymer (copolymer) of a plurality of types of monomers. Further, the polymer dispersant may be any of a random copolymer, a block copolymer or a graft copolymer. When the polymer dispersant is a graft copolymer, it may be a comb-shaped graft copolymer or a star-shaped graft copolymer. The polymer dispersant may be, for example, acrylic resin, polyester resin, polyurethane resin, polyamide resin, polyether, phenol resin, silicone resin, polyurea resin, amino resin, epoxy resin, polyamine such as polyethyleneimine and polyallylamine, and polyimide. It may be there.

Commercially available products can be used as the polymer dispersant, and the commercially available products include Ajinomoto Fine-Techno Co., Ltd.'s Azispar PB series, BYK's DISPERBYK series, BYK-series, and BASF's Efka series. Etc. can be used.

The viscosity of the ink composition described above at the ink temperature (for example, 25 ° C. or 40 ° C.) during inkjet printing may be, for example, 2 mPa · s or more from the viewpoint of ejection stability during inkjet printing, and may be 5 mPa · s or more. It may be 7 mPa · s or more. The viscosity of the ink composition at the ink temperature during inkjet printing 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 the ink temperature during inkjet printing 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. It may be s, 7 to 20 mPa · s, 7 to 15 mPa · s, or 7 to 12 mPa · s. In the present specification, the viscosity of the ink composition is, for example, the viscosity measured by an E-type viscometer.

When the viscosity of the ink composition at the ink temperature during inkjet printing is 2 mPa · s or more, the meniscus shape of the inkjet ink at the tip of the ink ejection hole of the ejection head is stable, so that the ejection control of the inkjet ink (for example, ejection) Control of amount and discharge timing) becomes easy. On the other hand, when the viscosity of the ink composition at the ink temperature at the time of inkjet printing is 20 mPa · s or less, the inkjet ink can be smoothly ejected from the ink ejection holes.

The surface tension of the ink composition is preferably a surface tension suitable for the inkjet method, specifically, is preferably in the range of 20 to 40 mN / m, and more preferably 25 to 35 mN / m. .. By setting the surface tension within the range, discharge control (for example, control of discharge amount and discharge timing) can be facilitated, and the occurrence of flight bending can be suppressed. The flight bending 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 stable, so that 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, it is possible to prevent the peripheral portion of the ink ejection hole from being contaminated with the inkjet ink, so that the occurrence of flight bending can be suppressed. That is, a pixel portion may not be accurately filled in the pixel portion forming region to be landed and the ink composition may be insufficiently filled, or a pixel portion forming region (or pixel portion) adjacent to the pixel portion forming region to be landed may be generated. The ink composition does not land on the surface and the color reproducibility does not deteriorate.

When the ink composition of the present embodiment is used as an ink composition for an inkjet method, it is preferably applied to a piezojet type inkjet recording device having a mechanical ejection mechanism using a piezoelectric element. In the piezo jet method, the ink composition is not instantaneously exposed to a high temperature during ejection. Therefore, alteration of the luminescent nanocrystal particles is unlikely to occur, and it is easier to obtain the expected luminescence characteristics in the pixel portion (light conversion layer).

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

When the ink composition is used in a photography method, first, the ink composition is applied onto a substrate, and then the ink composition is 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, since the alkaline developer is mostly an aqueous solution from the viewpoint of ease of waste liquid treatment of the developer, the coating film of the ink composition is treated with the aqueous solution. On the other hand, in the case of an ink composition using luminescent nanocrystal particles (quantum dots or the like), the luminescent nanocrystal particles are unstable with respect to water, and the luminescence (for example, fluorescence) is impaired by water. Therefore, in this embodiment, an inkjet method that does not need to be treated with an alkaline developer (aqueous solution) is preferable.

Further, even when the coating film of the ink composition is not treated with the alkaline developing solution, if the ink composition is alkali-soluble, the coating film of the ink composition easily absorbs moisture in the atmosphere. As time passes, the luminescence (for example, fluorescence) of luminescent nanocrystal particles (quantum dots, etc.) is impaired. 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 and / or an alkali-insoluble thermosetting resin as the photopolymerizable compound and / or the thermosetting resin. The fact that the coating film of the ink composition is alkaline insoluble means that the amount of the coating film of the ink composition dissolved at 25 ° C. in a 1% by mass potassium hydroxide aqueous solution 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 dissolved amount of the coating film of the ink composition is preferably 10% by mass or less, and more preferably 3% by mass or less. The fact that the ink composition is an ink composition capable of forming an alkali-insoluble coating film means that the thickness is obtained by applying the ink composition on a substrate and then drying it at 80 ° C. for 3 minutes. It can be confirmed by measuring the above-mentioned dissolution amount of the 1 μm coating film.

<Manufacturing method of ink composition>
The ink composition of the above-described embodiment can be obtained, for example, by mixing the constituent components of the above-mentioned ink composition and performing a dispersion treatment. Hereinafter, as an example, a method for producing an ink composition containing light-scattering particles and a polymer dispersant will be described.

The method for producing the ink composition includes, for example, a first step of preparing a dispersion of light-scattering particles containing a light-scattering particle and a polymer dispersant, and a dispersion of light-scattering particles and a luminescent nano. It comprises a second step of mixing the crystal particles. In this method, the dispersion of the light-scattering particles may further contain a photopolymerizable compound and / or a thermosetting resin, and in the second step, the photopolymerizable compound and / or the thermosetting resin is further mixed. You may. According to this method, the light scattering particles can be sufficiently dispersed. Therefore, it is possible to improve the optical characteristics of the pixel portion and easily obtain an ink composition having excellent ejection stability.

In the step of preparing the dispersion of the light-scattering particles, the light-scattering particles, the polymer dispersant, and in some cases, the photopolymerizable compound and / or the thermosetting resin are mixed and dispersed. A dispersion of light-scattering particles may be prepared. The mixing and dispersion treatment may be performed using a dispersion device such as a bead mill, a paint conditioner, a planetary stirrer, or a jet mill. It is preferable to use a bead mill or a paint conditioner from the viewpoint that the dispersibility of the light-scattering particles is good and the average particle size of the light-scattering particles can be easily adjusted to a desired range. By mixing the light-scattering particles and the polymer dispersant before mixing the luminescent nanocrystal particles and the light-scattering particles, the light-scattering particles can be more sufficiently dispersed. Therefore, excellent ejection stability and excellent external quantum efficiency can be obtained more easily.

The method for producing an ink composition may further include a step of preparing a dispersion of luminescent nanocrystal particles containing the luminescent nanocrystal particles and an organic solvent before the second step. In this case, in the second step, the dispersion of the light-scattering particles and the dispersion of the luminescent nanocrystal particles are mixed. In the step of preparing the dispersion of the luminescent nanocrystal particles, the luminescent nanocrystal particle dispersion may be prepared by mixing the luminescent nanocrystal particles and the organic solvent and performing a dispersion treatment. As the luminescent nanocrystal particles, luminescent nanocrystal particles having an organic ligand on the surface thereof may be used. That is, the luminescent nanocrystal particle dispersion may further contain an organic ligand. The mixing and dispersion treatment may be performed using a dispersion device such as a bead mill, a paint conditioner, a planetary stirrer, or a jet mill. It is preferable to use a bead mill, a paint conditioner or a jet mill from the viewpoint that the dispersibility of the luminescent nanocrystal particles is good and the average particle size of the luminescent nanocrystal particles can be easily adjusted to a desired range. According to this method, the luminescent nanocrystal particles can be sufficiently dispersed. Therefore, it is possible to improve the optical characteristics of the pixel portion and easily obtain an ink composition having excellent ejection stability. In the above step, the dispersion of the luminescent nanocrystal particles may further contain a photopolymerizable compound and / or a thermosetting resin.

In this production method, the organic solvent may be blended in the first step or may be blended in the second step. That is, the first step may be a step of preparing a dispersion of light-scattering particles containing light-scattering particles, a polymer dispersant, and an organic solvent, and the second step may be a step of preparing a dispersion of light-scattering particles. It may be a step of mixing a dispersion of light-scattering particles, luminescent nanocrystalline particles, and an organic solvent.

The method for producing an ink composition further comprises a step of mixing an organic solvent with a thermosetting resin and / or a photopolymerizable compound to prepare a solution containing the thermosetting resin and / or the photopolymerizable compound. May be good. In this case, in the second step, the light-scattering particle dispersion, the luminescent nanocrystal particle dispersion, the solution containing the thermosetting resin and / or the photopolymerizable compound prepared in the above step, and the organic solvent are used. May be mixed. That is, the second step may be a step of mixing a solution containing a light-scattering particle dispersion, a luminescent nanocrystal particle dispersion, a thermosetting resin and / or a photopolymerizable compound, and an organic solvent. ..

In this production method, components other than the above-mentioned components may be further used. In this case, the other components may be contained in the luminescent nanocrystal particle dispersion or may be contained in the light scattering particle dispersion. Further, other components may be mixed with a composition obtained by mixing a luminescent nanocrystal particle dispersion and a light scattering particle dispersion.

<Ink composition set>
The ink composition set of one embodiment includes the ink composition of the above-described embodiment. The ink composition set may include an ink composition (non-luminescent ink composition) containing no luminescent nanocrystal particles in addition to the ink composition (light emitting ink composition) of the above-described embodiment. The non-emission ink composition may be a conventionally known ink composition, and has the same composition as the ink composition (emission ink composition) of the above-described embodiment except that it does not contain luminescent nanocrystal particles. May be.

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

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

<Optical conversion layer and color filter>
Hereinafter, the details of the optical conversion layer and the color filter obtained by using the ink composition set of the above-described embodiment will be described with reference to the drawings. In the following description, the same reference numerals will be used for the same or equivalent elements, and duplicate description will be omitted.

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

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

The first pixel portion 10a and the second pixel portion 10b are luminescent pixel portions (light emitting pixel portions) containing the cured product of the ink composition of the above-described embodiment, respectively. The cured product contains luminescent nanocrystal particles, a cured component, and light-scattering particles. The curing component is a component obtained by the polymerization of the photopolymerizable compound and / or the curing (polymerization, cross-linking, etc.) of the thermosetting resin, and is a polymer of the photopolymerizable compound and / or a cured product of the thermosetting resin. include. That is, the first pixel portion 10a contains the first curing component 13a and the first luminescent nanocrystal particles 11a and the first light scattering particles 12a dispersed in the first curing component 13a, respectively. include. Similarly, the second pixel portion 10b includes the second curing component 13b and the second luminescent nanocrystal particles 11b and the 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 same as or different from the first light scattering particles 12a. It may be the same as or different from the second light-scattering particle 12b.

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

The content of the luminescent nanocrystal particles in the luminescent pixel portion is based on the total mass of the cured product of the luminescent ink composition from the viewpoint of being superior in the effect of improving the external quantum efficiency and obtaining excellent emission intensity. It is preferably 5% by mass or more. From the same viewpoint, the content of the luminescent nanocrystal particles may be 10% by mass or more, or 15% by mass or more, based on the total mass of the cured product of the luminescent ink composition. It may be 20% by mass or more. The content of the luminescent nanocrystal particles is preferably 80% by mass or less based on the total mass of the cured product of the luminescent ink composition from the viewpoint of excellent reliability of the pixel portion and excellent luminescence intensity. Is. From the same viewpoint, the content of the luminescent nanocrystal particles may be 75% by mass or less, or 70% by mass or less, based on the total mass of the cured product of the luminescent ink composition. It may be 60% by mass or less.

The content of the light-scattering particles in the luminescent pixel portion may be 0.1% by mass or more based on the total mass of the cured product of the luminescent ink composition from the viewpoint of being more excellent in the effect of improving the external quantum efficiency. It may be 1% by mass or more, 3% by mass or more, or 5% by mass or more. The content of the light-scattering particles is 60% by mass or less based on the total mass of the cured product of the luminescent ink composition from the viewpoint of excellent effect of improving the external quantum efficiency and excellent reliability of the pixel portion. It may be 50% by mass or less, 40% by mass or less, or 30% by mass or less.

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

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

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

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

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

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

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

In the color filter 100, for example, after the light-shielding portion 20 is formed in a pattern on the base material 40, the ink composition of the above-described embodiment is formed in the pixel portion-forming region partitioned by the light-shielding portion 20 on the base material 40. Inkjet ink) can be selectively adhered by an inkjet method, and the ink composition can be cured by irradiation with active energy rays or heating.

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

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

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

The drying temperature for volatilizing the organic solvent may be, for example, 50 ° C. or higher, and may be 150 ° C. or lower. The drying time may be, for example, 3 minutes or more and 30 minutes or less.

Although the color filter, the optical conversion layer, and one embodiment of these manufacturing methods have been described above, the present invention is not limited to the above embodiment.

For example, the light conversion layer is a pixel portion containing a cured product of a luminescent ink composition containing blue luminescent nanocrystal particles in place of or in addition to the third pixel portion 10c (3rd pixel portion 10c). It may be provided with a blue pixel portion). Further, even if the light conversion layer includes a pixel portion (for example, a yellow pixel portion) containing a cured product of a luminescent ink composition containing nanocrystal particles that emit light of colors other than red, green, and blue. good. In these cases, it is preferable that each of the luminescent nanocrystal particles contained in each pixel portion of the optical conversion layer has an absorption maximum wavelength in the same wavelength range.

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

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

Further, the color filter may include an ink receiving layer containing hydroxypropyl cellulose, polyvinyl alcohol, gelatin and the like between the base material and the pixel portion.

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

Further, in the manufacture of the color filter and the optical conversion layer, the pixel portion may be formed by a photolithography method instead of the inkjet method. In this case, first, the ink composition is coated on the base material in a layered manner to form an ink composition layer. Next, the ink composition layer is exposed in a pattern and then developed using a developing solution. In this way, 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 of the ink composition. However, in terms of material usage efficiency, the inkjet method is superior to the photolithography method. This is because, in principle, the photolithography method removes about two-thirds or more of the material, which wastes the material. Therefore, in the present embodiment, it is preferable to use an inkjet ink and form a pixel portion by an inkjet method.

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

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

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

<Preparation of organic solvent>
The organic solvents 1 to 4 shown in Table 1 below were prepared. The viscosity is the viscosity at 25 ° C., which is the viscosity measured by an E-type viscometer.

<Example 1>
(Preparation of red-emitting InP / ZnSeS / ZnS nanocrystal particle dispersion)
[Preparation of indium laurate solution]
10 g of 1-octadecene (ODE), 146 mg (0.5 mmol) of indium acetate and 300 mg (1.5 mmol) of lauric acid were added to the reaction flask to obtain a mixture. The mixture was heated at 140 ° C. for 2 hours under vacuum to obtain a transparent solution (indium laurate solution). This solution was kept in the glove box at room temperature until needed. Since indium laurate has low solubility at room temperature and easily precipitates, when using an indium laurate solution, the precipitated indium laurate in the solution (ODE mixture) is heated to about 90 ° C to become transparent. After forming the solution, the desired amount was weighed and used.

[Preparation of core (InP core) of red luminescent nanocrystal 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 in a nitrogen (N ₂ ) environment and then at 250 ° C. for 20 minutes under vacuum. The reaction temperature (mixture temperature) was then raised to 300 ° C. under a nitrogen (N ₂ ) 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. Then 8 ml of toluene and 20 ml of ethanol were added to the reaction solution in the glove box. Subsequently, centrifugation was performed to precipitate InP nanocrystal particles, and then the supernatant was tilted to obtain InP nanocrystal particles. Then, the obtained InP nanocrystal particles were dispersed in hexane. As a result, a dispersion liquid (hexane dispersion liquid) containing 5% by mass of InP nanocrystal particles was obtained.

The hexane dispersion of the InP nanocrystal particles obtained above and the indium phosphide solution were placed in a reaction flask to obtain a mixture. The charged amounts of the hexane dispersion of InP nanocrystal particles and the indium laurate solution were adjusted to 0.5 g (25 mg for InP nanocrystal particles) and 5 g (178 mg for indium laurate), respectively. After allowing the mixture to stand at room temperature for 10 minutes under vacuum, the inside of the flask was returned to normal pressure with nitrogen gas, the temperature of the mixture was raised to 230 ° C., and the temperature was maintained for 2 hours to remove hexane from the inside of the flask. .. Then, the temperature inside the flask was raised to 250 ° C., a mixture of 3 g of 1-octadecene (ODE) and 0.03 g (0.125 mmol) of tris (trimethylsilyl) phosphine was rapidly introduced into the reaction flask, and the reaction temperature was 230 ° C. Maintained in. After 5 minutes, the reaction was stopped by removing the heater and the resulting reaction solution was cooled to room temperature. Then, 8 ml of toluene and 20 ml of ethanol were added to the reaction solution in the glove box. Subsequently, centrifugation is performed to precipitate InP nanocrystal particles (InP core), which are the cores of red luminescent InP / ZnSeS / ZnS nanocrystal particles, and then the InP nanocrystal particles (InP core) are tilted by tilting the supernatant. Got Next, the obtained InP nanocrystal particles (InP core) were dispersed in hexane to obtain a dispersion liquid (hexane dispersion liquid) containing 5% by mass of the InP nanocrystal particles (InP core).

[Formation of shell (ZnSeS / ZnS shell) of red luminescent nanocrystal particles]
After adding 2.5 g of the hexane dispersion of the InP nanocrystal particles (InP core) 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. It was held for 2 hours. Then, 14 mg of diethylzinc, 8 mg of bis (trimethylsilyl) selenide and 7 mg of hexamethyldisirateyan (ZnSeS precursor solution) dissolved in 1 ml of ODE were added dropwise to this reaction mixture, and the temperature was raised to 200 ° C. and held for 10 minutes. This formed a ZnSeS shell with a thickness of 0.5 monolayer.

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 hexamethyldisiratean in 2 ml of ODE was added dropwise to this reaction mixture, and the temperature was raised to 200 ° C. and maintained for 30 minutes. A ZnS shell with a thickness of 2 monolayers was formed. After 10 minutes of dropping the ZnS precursor solution, the reaction was stopped by removing the heater. Next, the reaction mixture was cooled to room temperature, and the obtained white precipitate was removed by centrifugation, so that a transparent nanocrystal particle dispersion (InP / ZnSeS) in which red luminescent InP / ZnSeS / ZnS nanocrystal particles were dispersed was dispersed. / ODE dispersion of ZnS nanocrystal particles) was obtained.

[Synthesis of organic ligands for InP / ZnSeS / ZnS nanocrystal particles]
(Synthesis of organic ligand)
After putting JEFAMINE M-1000 (manufactured by Huntsman) into a flask, succinic anhydride (manufactured by Sigma-Aldrich) having an equimolar amount with JEFAMINE M-1000 was added thereto while stirring in a nitrogen gas environment. 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 red luminescent InP / ZnSeS / ZnS nanocrystal particle dispersion by ligand exchange]
30 mg of the organic ligand was added to 1 ml of the ODE dispersion of the InP / ZnSeS / ZnS nanocrystal particles obtained above. Then, the ligand was exchanged by heating at 90 ° C. for 5 hours. As the ligand exchange progressed, aggregation of nanocrystal particles was observed. After the ligand exchange was completed, the supernatant was tilted to obtain nanocrystal particles. Then, 3 ml of ethanol was added to the obtained nanocrystal particles, and the particles were ultrasonically treated and redispersed. 10 ml of n-hexane was added to 3 mL of the ethanol dispersion of the obtained nanocrystal particles. Subsequently, centrifugation was performed to precipitate the nanocrystal particles, and then the supernatant was tilted and dried under vacuum to obtain nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles modified with the above organic ligand). The content of the organic ligand in the total amount of the nanocrystal particles modified with the organic ligand was about 30% by mass. The obtained nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles modified with the above organic ligand) are dispersed in the organic solvent 1 so that the content in the dispersion is 50% by mass, thereby emitting red light. A sex nanocrystal particle dispersion was obtained.

(Preparation of thermosetting resin solution)
4.788 g of a thermosetting resin (trade name: EPICLON EXA-4850-150, manufactured by DIC Corporation) and 3.192 g of an organic solvent were mixed to prepare a resin solution of 60% by mass. 7.98 g of this resin solution, 1.96 g of a curing agent (trade name: Ricacid HNA-100, manufactured by Shin Nihon Rika Co., Ltd.), and a curing catalyst (trade name: Hishikorin PX-4MP, manufactured by Nippon Kagaku Kogyo Co., Ltd.) 0 .0065 g and 1 0.0565 g of the organic solvent were mixed to obtain a thermosetting resin solution 1 (solid content concentration 67.5% by mass).

(Preparation of light-scattering particle dispersion)
30 g of light-scattering particles (titanium oxide, trade name: MPT-141, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 100 nm, rutile type, aluminum hydroxide surface-treated product) and a polymer dispersant. 5.0 g of (trade name: DISPERBYK-2164, active ingredient 60%, manufactured by Big Chemie) and 127.0 g of an organic solvent were mixed to prepare a mixed solution having a solid content concentration of 55% by mass. After adding zirconia beads (diameter: 0.3 mm) to the mixed solution, the mixed solution was dispersed by shaking with a paint conditioner for 2 hours. The light-scattering particle dispersion 1 was obtained by removing the zirconia beads with a polyester mesh filter.

(Preparation of ink composition)
2.45 g of the red light-emitting nanocrystal particle dispersion, 1.09 g of the light-scattering particle dispersion 1, and 1.01 g of the thermosetting resin solution 1 were uniformly mixed in a container filled with argon gas. After mixing, the mixture was filtered in a glove box with a filter having a pore size of 5 μm. Further, it was introduced into a container containing a filtrate obtained by argon gas, and the inside of the container was saturated with argon gas. Then, the pressure was reduced to remove the argon gas, whereby an ink composition having a solid content concentration of 50% by mass was obtained.

(Evaluation of viscosity increase rate)
The viscosity of the luminescent nanocrystal particle dispersion (sol solution) and the viscosity of the ink composition were measured with an E-type viscometer, and the viscosity increase rates A and B were calculated based on the following formulas. The results are shown in Table 2.
Viscosity increase rate A = viscosity of sol solution / viscosity of organic solvent x 100
Viscosity increase rate B = Viscosity of ink composition / Viscosity of organic solvent x 100

<Example 2, Example 3 and Comparative Example 1>
The ink compositions of Example 2, Example 3 and Comparative Example 1 were prepared in the same manner as in Example 1 except that the organic solvents 2 to 4 were used instead of the organic solvent 1. Further, in each Example and Comparative Example, the viscosity of the luminescent nanocrystal particle dispersion (sol solution) and the viscosity of the ink composition were measured in the same manner as in Example 1, and the viscosity increase rate A and the viscosity increase rate B were measured. Was calculated. The results are shown in Table 2.

10 ... Pixel part, 10a ... First pixel part, 10b ... Second pixel part, 10c ... Third pixel part, 11a ... First luminescent nanocrystal particles, 11b ... Second luminescent nanocrystal particles , 12a ... 1st light-scattering particles, 12b ... 2nd light-scattering particles, 12c ... 3rd light-scattering particles, 20 ... light-shielding part, 30 ... light conversion layer, 40 ... base material, 100 ... color filter.

Claims (12)

An inkjet ink composition containing luminescent nanocrystal particles, a photopolymerizable compound and / or a thermosetting resin, and an organic solvent.
The concentration of the luminescent nanocrystal particles is 10% by mass or more, and the concentration is 10% by mass or more.
The luminescent nanocrystal particles have an organic ligand on their surface and
The organic ligand comprises one or more functional groups capable of binding to the luminescent nanocrystal particles and a polyoxyalkylene group.
An ink composition for an inkjet in which the organic solvent contains a polyoxyalkylene group having the same oxyalkylene structure as the polyoxyalkylene group and does not contain an ester group. The ink jet ink composition according to claim 1, wherein the polyoxyalkylene group contained in the organic ligand has an oxyalkylene structure represented by the following formula (1).

[In the formula (1), R ¹ and R ² independently represent a hydrogen atom, a methyl group or an ethyl group, and * indicates a bond. ] The ink jet ink composition according to claim 1 or 2, wherein the polyoxyalkylene group contained in the organic solvent has a degree of polymerization of 2 to 4. The inkjet ink composition according to any one of claims 1 to 3, wherein both ends of the main chain of the organic solvent are alkyl groups having 1 to 4 carbon atoms. The inkjet ink composition according to any one of claims 1 to 4, wherein the organic solvent is a compound represented by the following formula (2).

[In the formula (2), a plurality of R ¹ and R ² independently represent a hydrogen atom, a methyl group or an ethyl group, and R ³ and R ⁴ independently have 1 to 4 carbon atoms. It represents an alkyl group, where n is an integer of 2-4. ] The inkjet ink composition according to any one of claims 1 to 5, wherein the organic ligand has a weight average molecular weight of 350 or more. The inkjet ink composition according to any one of claims 1 to 6, further comprising light-scattering particles. The ink jet ink composition according to any one of claims 1 to 7, which is used for forming an optical conversion layer. A plurality of pixel portions and a light-shielding portion provided between the plurality of pixel portions are provided.
The plurality of pixel portions are light conversion layers having a light emitting pixel portion containing a cured product of the inkjet ink composition according to any one of claims 1 to 8. As the light emitting pixel portion,
A first luminescent pixel portion containing luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having a emission peak wavelength in the range of 605 to 665 nm.
A second luminescent pixel portion containing luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having a emission peak wavelength in the range of 500 to 560 nm.
9. The optical conversion layer according to claim 9. The light conversion layer according to claim 9 or 10, further comprising a non-light emitting pixel portion containing light scattering particles. A color filter comprising the optical conversion layer according to any one of claims 9 to 11.

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