JP7020014B2 - 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 color filter pixel portion in a display such as a liquid crystal display device uses, for example, a curable resist material containing red organic pigment particles or green organic pigment particles and an alkali-soluble resin and / or an acrylic monomer. , Has been manufactured by photolithography.

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 color filter pixel portion such as a red pixel and a green pixel by using the above is 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 (Patent Document 1).

International Publication No. 2008/001693

When a color filter pixel portion (hereinafter, also simply referred to as “pixel portion”) is formed by an ink composition using luminescent nanocrystal particles such as quantum dots, the quantum dots are unstable and are used as a binder. Depending on the type of resin, for example, storage at room temperature in air may reduce the external quantum efficiency over time.

Therefore, an object of the present invention is to provide an ink composition capable of suppressing a decrease in external quantum efficiency, and an optical conversion layer and a color filter using the ink composition.

One aspect of the present invention relates to an ink composition containing luminescent nanocrystal particles and an acrylic polymer. In this ink composition, the acrylic polymer has an epoxy group, and the epoxy equivalent of the acrylic polymer is less than 560 g / eq. Since this ink composition contains an acrylic polymer having an epoxy group and having an epoxy equivalent of less than 560 g / eq, a decrease in external quantum efficiency is suppressed.

The ink composition may further contain light scattering particles.

The average particle size of the light-scattering particles may be 0.05 to 1.0 μm.

The light-scattering particles may contain at least one selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate and silica.

The ink composition may further contain a polymer dispersant.

The weight average molecular weight of the polymer dispersant may be 1000 or more.

In the ink composition, the acrylic polymer may be alkali-insoluble.

The ink composition may be an ink composition capable of forming an alkali-insoluble coating film.

The surface tension of the ink composition may be 20-40 mN / m.

The viscosity of the ink composition may be 2 to 20 mPa · s.

The ink composition may further contain a solvent having a boiling point of 180 ° C. or higher.

The ink composition may be for a color filter.

The ink composition may be an ink composition (inkjet ink) used in an inkjet method.

One aspect of the present invention relates to an optical conversion layer including a plurality of pixel portions, wherein the plurality of pixel portions have pixel portions containing a cured product of the ink composition described above. This light conversion layer can be obtained by an inkjet method using the above-mentioned ink composition. Therefore, according to this optical conversion layer, leakage light in the pixel portion is unlikely to occur, and excellent optical characteristics can be easily obtained.

The optical conversion layer may further include a light-shielding portion provided between the plurality of pixel portions, and the plurality of pixel portions contain the above-mentioned cured product and have a wavelength in the range of 420 to 480 nm as luminescent nanocrystal particles. The first pixel portion containing the light-emitting nanocrystal particles that absorb the light of the above and emit light having a light emission peak wavelength in the range of 605 to 665 nm, and the cured product, and as the light-emitting nanocrystal particles. It may have a second pixel portion containing luminescent nanoparticles 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.

The plurality of pixel portions may further include a third pixel portion having a transmittance of 30% or more with respect to light having a wavelength in the range of 420 to 480 nm.

One aspect of the present invention relates to a color filter including the above-mentioned optical conversion layer. According to this color filter, excellent optical characteristics can be easily obtained.

According to the present invention, it is possible to provide an ink composition capable of suppressing a decrease in external quantum efficiency, and an optical conversion layer and a color filter using the ink composition.

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 contains luminescent nanocrystal particles and an acrylic polymer, preferably further containing light-scattering particles, and more preferably further containing a polymer dispersant. In this ink composition, the acrylic polymer has an epoxy group, and the epoxy equivalent of the acrylic polymer is less than 560 g / eq. The ink composition of one embodiment is an ink composition for a color filter used for forming a pixel portion of a color filter by, for example, a photolithography method, an inkjet method, or the like. Since the ink composition having the above structure contains an acrylic polymer having an epoxy group and an epoxy equivalent of less than 600 g / eq, it is possible to suppress a decrease in external quantum efficiency. That is, this ink composition is suitably used for applications in which a color filter pixel portion is formed by an inkjet method.

In the following, an ink composition for a color filter used in an inkjet method (inkprint ink for a color filter) containing luminescent nanocrystal particles, an acrylic polymer, a light scattering particle, and a polymer dispersant. 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 that emit light having an emission peak wavelength in the range of 605 to 665 nm (red light), and may be light having an emission peak wavelength in the range of 500 to 560 nm. It may be a green light emitting nanocrystal particle that emits (green light), or may be a blue light emitting nanocrystal particle that emits light (blue light) having an emission peak wavelength in the range of 420 to 480 nm. .. 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 may be, for example, light having a wavelength in the range of 400 nm or more and less than 500 nm (blue light) or light having a wavelength in the range of 200 nm to 400 nm (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 an ultraviolet-visible spectrophotometer.

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-emitting 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 at 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 (hereinafter, also referred to as “QD”), quantum rods, and the like. 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, and HgSe. CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, CdHgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSeTe, CdHgSeTe, AlHgSe InP, InAs, InSb, COLP, 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, PbSnPbSn 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, the shell portion is ZnS and the inner core portion is InP, and the nanocrystal particles have a core / shell structure. The shell portion is a mixed crystal of ZnS and ZnSeS and the inner core portion 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 ZnSeS, 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-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 of CdS, nanocrystal particles having a core / shell structure, and the shell portion is ZnS and the inner core portion is InP. Nanocrystal particles having a structure, wherein the shell portion is a mixed crystal of ZnS and ZnSeS and the inner core portion is InP, and the nanocrystal 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 nanocrystal 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 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-shaped, branched, net-shaped, rod-shaped, 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 or equal to 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.

From the viewpoint of dispersion stability, the luminescent nanocrystal particles preferably have an organic ligand on the surface thereof. 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. Further, 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, the organic ligand is removed from the luminescent nanocrystal particles having the above-mentioned organic ligand, and the organic ligand is exchanged with the polymer dispersant to cause the polymer dispersant on the surface of the luminescent nanocrystal particles. May be combined. 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 organic ligand, a functional group for ensuring affinity with a resin and a solvent (hereinafter, also simply referred to as "affinity group") and a functional group for ensuring adsorption to luminescent nanocrystals (hereinafter, simply referred to as "affinity group"). Hereinafter, it is preferable that the compound has simply "adsorption group"). As the affinity group, an aliphatic hydrocarbon group is preferable. The aliphatic hydrocarbon group may be a linear type or may have a branched structure. Further, the aliphatic hydrocarbon group may have an unsaturated bond or may not have an unsaturated bond. Examples of the adsorption group include a hydrogen 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, an alkoxyxysilyl and the like. Examples of the organic ligand include TOP (trioctylphosphine), TOPO (trioctylphosphine oxide), oleic acid, oleylamine, octylamine, trioctylamine, hexadecylamine, octanethiol, dodecanethiol, and hexylphosphonic acid ( HPA), tetradecylphosphonic acid (TDPA), and octylphosphinic acid (OPA).

［式（１）中、ｐは０～５０の整数を示し、ｑは０～５０の整数を示す。］ The organic ligand preferably has an aliphatic hydrocarbon having an ethylene oxide chain and / or a propylene oxide chain as an affinity group from the viewpoint of further improving the dispersibility and luminescence intensity of the luminescent nanocrystal particles. .. The organic ligand may be, for example, an organic ligand represented by the following general formula (1).

[In equation (1), p indicates an integer of 0 to 50, and q indicates an integer of 0 to 50. ]

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

As the luminescent nanocrystal particles, those dispersed in a colloidal form in an organic solvent 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. Examples of the organic solvent include cyclohexane, hexane, heptane, chloroform, toluene, octane, chlorobenzene, tetralin, diphenyl ether, propylene glycol monomethyl ether acetate, butyl carbitol acetate, or a mixture thereof.

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 is 5% by mass or more based on the mass of the non-volatile content of the ink composition from the viewpoint of being superior in the effect of reducing leakage light and further improving the light emitting characteristics of the ink composition. It may be 10% by mass or more, 15% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more. good. The content of the luminescent nanocrystal particles may be 70% by mass or less, 60% by mass or less, 55 by mass, based on the mass of the non-volatile content of the ink composition from the viewpoint of excellent ejection stability. It may be 50% by mass or less, or 50% by mass or less. When the luminescent nanocrystal particles are modified with an organic ligand, the total amount of the luminescent nanocrystal particles and the organic ligand that modifies the luminescent nanocrystal particles may be in the above range. In the present specification, the "mass of the non-volatile component of the ink composition" refers to the mass obtained by subtracting the mass of the solvent from the total mass of the ink composition when the ink composition contains a solvent, and the ink composition refers to the ink composition. In the absence of solvent, it refers to the total mass of the ink composition.

[Epoxy group-containing acrylic polymer]
The epoxy-containing acrylic polymer of the present embodiment has an epoxy group, and the epoxy equivalent of the acrylic polymer is less than 560 g / eq (hereinafter, also referred to as “epoxy group-containing acrylic polymer”). In the present embodiment, since the ink composition contains an acrylic polymer having an epoxy group, the cured product of the ink composition is excellent in heat resistance and storage stability, and is applied to a light-shielding portion (for example, a black matrix) and a substrate. Excellent adhesion. Further, by using the epoxy group-containing acrylic polymer, excellent transparency can be obtained after curing, and good optical characteristics can be obtained. As the epoxy group-containing acrylic polymer, one type may be used alone, or two or more types may be used in combination.

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 epoxycyclohexyl group, or the like. The number of epoxy groups in one molecule of the epoxy group-containing acrylic polymer is preferably 2 or more, and more preferably 4 or more, from the viewpoint of increasing the crosslink density. In particular, when an epoxy group-containing acrylic polymer having a weight average molecular weight of 10,000 or less is used in order to further improve the ejection stability from the ejection head in the inkjet method, the strength of the pixel portion (cured product of the ink composition) is used. And since the hardness tends to decrease, the crosslink density can be sufficiently increased by setting the number of epoxy groups to 4 or more. The number of epoxy groups is preferably 50 or less, more preferably 20 or less. The number of epoxy groups is preferably 2 to 50, more preferably 2 to 20, and even more preferably 4 to 20.

The epoxy equivalent of the epoxy group-containing acrylic polymer is less than 560 g / eq. The epoxy equivalent of the epoxy group-containing acrylic polymer is 500 g / eq or less from the viewpoint that the crosslink density can be increased and the strength and hardness of the pixel portion (cured product of the ink composition) can be further increased. It may be 400 g / eq or less. The epoxy equivalent of the acrylic polymer may be 100 g / eq or more, 130 g / eq or more, 150 g / eq or more, or 200 g / eq from the viewpoint of suppressing shrinkage due to curing. It may be the above. The epoxy equivalent can be measured by, for example, JIS K7236: 2001.

The epoxy group-containing acrylic polymer is also referred to as a monomer having an epoxy group and a substituted or unsubstituted acryloyl group (for example, acryloyl group, α-alkylacryloyl group) (hereinafter, also referred to as “epoxy group-containing acrylic monomer”). ), A copolymer of an epoxy group-containing acrylic monomer and another monomer (a monomer other than the epoxy group-containing acrylic monomer), or the like. The polymer of the epoxy group-containing acrylic monomer may be a polymer of a single monomer (homopolymer) or a copolymer of a plurality of types of monomers. The ratio of the epoxy group-containing acrylic monomer unit (structural unit derived from the epoxy group-containing acrylic monomer) in the epoxy group-containing acrylic polymer is 1% by mass or more and 10% by mass based on the total amount of the epoxy group-containing acrylic polymer. % Or more, or 20% by mass or more, and may be 90% by mass or less, 80% by mass or less, or 70% by mass or less.

Examples of the epoxy group-containing acrylic monomer include glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate, glycidyl α-n-propyl acrylate, glycidyl α-n-butyl acrylate, and -3,4-epoxybutyl acrylate. , Acrylic acid-3,4-epoxybutyl, acrylic acid-4,5-epoxypentyl, methacrylic acid-4,5-epoxypentyl, acrylic acid-6,7-epoxypentyl, methacrylic acid-6,7-epoxypentyl , Α-ethylacrylic acid-6,7-epoxypentyl, β-methylglycidyl acrylate, β-methylglycidyl methacrylate, -3,4-epoxycyclohexyl acrylate, -3,4-epoxycyclohexyl methacrylate, lactone modification Acrylic acid-3,4-epoxycyclohexyl, lactone-modified methacrylic acid-3,4-epoxycyclohexyl and the like can be mentioned. These may be used alone or in combination of two or more. The epoxy group-containing acrylic monomer is preferably at least one selected from the group consisting of glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate and glycidyl α-n-propyl acrylate, and more preferably acrylic acid. It is glycidyl or glycidyl methacrylate.

The other monomer may be a monomer having no epoxy group and containing a group having a carbon-carbon unsaturated bond as a group capable of cross-linking with the epoxy group-containing acrylic monomer (first other monomer). It may be a monomer having no substituted or unsubstituted acryloyl group and having an epoxy group (second other monomer). Examples of the first other monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-butyl (meth). Alkyl (meth) acrylates having an alkyl group having 1 to 22 carbon atoms such as acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate; benzyl (meth) acrylate, 2-phenylethyl (meth) acrylate. Aralkyl (meth) acrylates such as cyclohexyl (meth) acrylates, cycloalkyl (meth) acrylates such as isobornyl (meth) acrylates; ω such as 2-methoxyethyl (meth) acrylates and 4-methoxybutyl (meth) acrylates. -Alkylalkyl esters of crotonic acids such as alkoxyalkyl (meth) acrylates, methyl crotonate, ethyl crotonate; unsaturated dibasic acids such as dimethylmalate, di-n-butylmalate, dimethylfumarate, dimethylitaconate. Dialkyl esters, acrylonitriles; α-olefins such as ethylene, propylene, 1,3-butadiene, cyclopentylethylene; styrene, 1-ethynyl-4-methylbenzene, divinylbenzene, 1-ethynyl-4-methylethylbenzene, p- Vinyl compounds having an aromatic ring such as tert-butylstyrene, 4-vinylbiphenyl, 4-ethynylbenzyl alcohol, 2-ethynylnaphthalene, phenanthrene-9-ethynyl; vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, chlorotrifluoro Fluoroolefins such as ethylene; carboxylic acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate and the like can be mentioned. When a vinyl compound having an aromatic ring is used as the first other monomer, styrene or p-tert-butyl styrene is preferably used. Examples of the second other monomer include vinylcyclohexene oxide and the like. The other monomers may be used alone or in combination of two or more.

［式（２）中、Ｒ^１は水素原子又はメチル基を示し、Ｒ^２は２価の基を示す。］ The epoxy group-containing acrylic polymer may contain, for example, a structural unit represented by the following formula (2). The epoxy group-containing acrylic polymer may contain one type of structural unit represented by the following formula (2) alone, or may contain two or more types in combination. The epoxy group-containing acrylic polymer may contain a structural unit represented by the following formula (2) and may contain a structural unit derived from the above-mentioned other monomer.

[In the formula (2), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a divalent group. ]

The ^divalent group represented by R2 may be, for example, a substituted or unsubstituted divalent hydrocarbon group, preferably an alkylene group. The hydrocarbon group or the alkylene group has, for example, 1 to 12 carbon atoms, preferably 1 to 8, more preferably 1 to 4, still more preferably 1 to 2, and particularly preferably 1.

The ratio of the structural unit represented by the formula (2) in the epoxy group-containing acrylic polymer is 1% by mass or more, 10% by mass or more, or 20% by mass or more based on the total amount of the epoxy group-containing acrylic polymer. It may be 90% by mass or less, 80% by mass or less, or 70% by mass or less.

Examples of the epoxy group-containing acrylic polymer include polyglycidyl (meth) acrylate, methyl (meth) acrylate-glycidyl (meth) acrylate copolymer, benzyl (meth) acrylate-glycidyl (meth) acrylate copolymer, and n. -Butyl (meth) acrylate-glycidyl (meth) acrylate copolymer, 2-hydroxyethyl (meth) acrylate-glycidyl (meth) acrylate copolymer, (3-ethyl-3-oxetanyl) methyl (meth) acrylate-glycidyl Examples thereof include (meth) acrylate copolymers and styrene-glycidyl (meth) acrylates.

The method for obtaining the epoxy group-containing acrylic polymer (method for polymerizing or copolymerizing the above-mentioned monomers) is not particularly limited, and known polymerization methods, solvents, polymerization initiators and the like can be used. Examples of the polymerization method include a massive radical polymerization method, a solution radical polymerization method, and a non-aqueous dispersion radical polymerization method. The epoxy group-containing acrylic polymer may be obtained by a polymerization reaction of an epoxy group-containing monomer, or may be obtained by introducing an epoxy group into a polymer obtained by a polymerization reaction of another monomer.

Examples of the polymerization initiator include 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), and 2,2'-azobis (2-methylbutyronitrile). ), tert-Butylperoxypivalate, tert-butylperoxybenzoate, tert-butylperoxy-2-ethylhexanoate, di-tert-butylperoxide, cumenehydroperoxide, diisopropylperoxycarbonate and the like. Be done.

Specific examples of the epoxy group-containing acrylic polymer include "Findick A-247S", "Findick A-254", "Findick A-253", and "Findick A-229-" manufactured by DIC Corporation. "30A", "Findick A-261", "Findick A-249", "Findick A-266", "Findick A-241", "Findick A-272" (trade name), etc. can be used. can.

The weight average molecular weight of the epoxy group-containing acrylic polymer has a viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, a viewpoint that the curability of the ink composition is good, a viewpoint that the ejection stability is excellent, and a pixel portion (ink). From the viewpoint of improving the solvent resistance and wear resistance of the cured product of the composition), it may be 750 or more, 1000 or more, or 2000 or more. Epoxy groups are replenished in the ink composition (inkjet ink) to increase the concentration of the reaction point of the epoxy to increase the crosslink density, from the viewpoint of obtaining an appropriate viscosity as an inkjet ink, and ejection stability. From a more superior point of view, it may be 500,000 or less, 300,000 or less, 200,000 or less, 100,000 or less, 50,000 or less, or 20,000 or less. good. However, this does not apply to the molecular weight after cross-linking. In the present specification, the weight average molecular weight is a polystyrene-equivalent weight average molecular weight measured by GPC (Gel Permeation Chromatography).

The epoxy group-containing acrylic polymer may be alkali-insoluble from the viewpoint that a color filter pixel portion having excellent reliability can be easily obtained. The fact that the epoxy group-containing acrylic polymer is alkaline-insoluble means that the amount of the epoxy group-containing acrylic polymer dissolved at 25 ° C. in a 1% by mass potassium hydroxide aqueous solution is the total mass of the epoxy group-containing acrylic polymer. As a standard, it means that it is 30% by mass or less. The dissolved amount of the epoxy group-containing acrylic polymer is preferably 10% by mass or less, and more preferably 3% by mass or less.

The content of the epoxy group-containing acrylic polymer 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 resistance of the pixel portion (cured product of the ink composition). From the viewpoint of improving the solvent property and the abrasion 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 non-volatile content of the ink composition. good. The content of the epoxy group-containing acrylic polymer is the mass of the non-volatile 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. As a reference, it may be 90% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less. good.

The epoxy group-containing acrylic polymer may be used as a thermosetting resin that is crosslinked and cured by heat, and is used as a photoradical polymerizable compound (resin) or a photocationic polymerizable compound (resin) that polymerizes by irradiation with light. May be done. In other words, the ink composition may contain a thermosetting component or a photopolymerizable component containing an epoxy group-containing acrylic polymer. In addition to these, a polymer that does not have a polymerization reactivity by itself may be further used.

When the epoxy group-containing acrylic polymer is used as a thermosetting resin, it is usually used in combination with a curing agent. A catalyst (curing catalyst) capable of accelerating the thermosetting reaction may be further added to the ink composition. Examples of the curing agent and curing catalyst include 4-methylhexahydrophthalic anhydride, triethylenetetramine, diaminodiphenylmethane, phenol novolac resin, tris (dimethylaminomethyl) phenol, N, N-dimethylbenzylamine, 2-. Examples thereof include ethyl-4-methylimidazole, triphenylphosphine, 3-phenyl-1,1-dimethylurea and the like.

When the epoxy group-containing acrylic polymer is used as a photoradical polymerizable compound or a photocationic polymerizable compound, it is usually used together with a photopolymerization initiator. 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.

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-morpholinophenyl) -butane-1-one, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, (2,4,6-trimethylbenzoyl) ethoxyphenyl Phenyloxide or the like is 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.

Examples of the photocationic polymerization initiator include polyarylsulfonium salts such as triphenylsulfonium hexafluoroantimonate and triphenylsulfonium hexafluorophosphate; diphenyliodonium hexafluoroantimonate and P-nonylphenyliodonium hexafluoroantimonate. Examples thereof include polyaryliodonium salts such as nate.

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. 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 less than or equal to 20 parts by mass or less.

[Light scattering particles]
The light-scattering particles are, for example, optically inert inorganic particles. The light-scattering particles can scatter the light from the light source irradiated to the color filter pixel portion.

Materials constituting the light-scattering particles include, for example, simple metal 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, titanium oxide, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, alumina white, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, zinc oxide; magnesium carbonate, Metal carbonates such as barium carbonate, bismuth subcarbonate, calcium carbonate; metal hydroxides such as aluminum hydroxide; composite oxides such as barium zirconate, calcium zirconate, calcium titanate, barium titanate, strontium titanate, etc. Examples thereof include metal salts such as bismuth subnitrate. The light-scattering particles are selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate and silica from the viewpoint of excellent ejection stability and reduction effect of leaked light. It preferably contains seeds, and more preferably contains at least one selected from the group consisting of titanium oxide, barium sulfate and calcium carbonate.

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 more 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 or more from the viewpoint of being superior in the effect of reducing leakage light and further improving the light emission characteristics of the ink composition. , 0.1 μm or more, or 0.2 μm or more. The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition may be 1.0 μm or less, 0.6 μm or less, or 0, from the viewpoint of excellent ejection stability. It may be 0.4 μm 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, 0.1 to 1 It may be 0.0 μm, 0.1 to 0.6 μm, 0.1 to 0.4 μm, 0.2 to 1.0 μm, 0.2 to 0.6 μm, or 0.2 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 50 nm or more, and may be 1000 nm or less. 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 may be 0.1% by mass or more, or even 1% by mass or more, based on the mass of the non-volatile content of the ink composition from the viewpoint of excellent effect of reducing leakage light. 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 non-volatile content of the ink composition from the viewpoint of excellent ejection stability and the effect of reducing leakage light. It may be less than or equal to 40% by mass, may be 30% by mass or less, may be 25% by mass or less, may be 20% by mass or less, and may be 15% by mass. It may be as follows. In the present embodiment, since 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 within the above range.

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 reducing leakage light. It may be 0.2 or more, and may be 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 reducing leakage light and excellent continuous ejection property (ejection stability) during inkjet printing. It may be 2.0 or less, or 1.5 or less. The reduction of leaked light by the light-scattering particles is considered to be due to the following mechanism. That is, in the absence of light-scattering particles, the backlight light only travels almost straight through the pixel portion and is considered to have little chance of being absorbed by the luminescent nanocrystal particles. On the other hand, when the light-scattering particles are present in the same pixel portion as the luminescent nanocrystal particles, the backlight light is scattered in all directions in the pixel portion, and the luminescent nanocrystal particles can receive the light. Even if the same backlight is used, it is considered that the amount of light absorption in the pixel portion increases. As a result, it is considered that such a mechanism makes it possible to prevent light leakage.

[Polymer dispersant]
In the present invention, 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, and has a function of dispersing the light-scattering particles. Have. 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 bound to the surface of the light-scattering particles and adsorbed to the light-scattering particles, but is bound to the surface of the luminescent nanoparticles and adsorbed to the luminescent nanoparticles. It may be free in the ink composition.

By the way, one of the causes of deterioration of ejection stability when forming a color filter pixel portion by an inkjet method using a conventional ink composition is considered to be aggregation of luminescent nanocrystal particles and light scattering particles. .. Therefore, it is conceivable to improve the ejection stability by refining the luminescent nanocrystal particles and the light scattering particles, reducing the content of the luminescent nanocrystal particles and the light scattering particles, and the like. In this case, the effect of reducing leakage light tends to decrease, and it is difficult to achieve both ejection stability and reduction of leakage light at a high level. On the other hand, according to the ink composition further containing the polymer dispersant, excellent ejection stability and reduction of leakage light can be achieved at a high level. The reason why such an effect is obtained is not clear, but it is because the polymer dispersant remarkably suppresses the aggregation of luminescent nanocrystal particles and light scattering particles (particularly, light scattering particles). It is inferred that.

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 phosphoric acid 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 phosphin oxide group and a phosphin sulfide group.

Acidic functionality from the viewpoint of dispersion stability of light-scattering particles, less likely to cause the side effect of sedimentation of luminescent nanocrystal particles, ease of synthesis of polymer dispersant, and stability of functional groups. As the group, a carboxyl group, a sulfo group, a phosphonic acid group and a phosphoric acid group are preferably used, and as a basic functional group, an amino group is preferably used. Among these, a carboxyl group, a phosphonic acid group and an amino group are more preferably used, and most preferably an amino group is used.

Polymer dispersants with acidic functional groups have an acid value. The acid value of the polymer dispersant having an acidic functional group is preferably 1 to 150 mgKOH / g. When the acid value is 1 mgKOH / g or more, sufficient dispersibility of the light-scattering particles can be easily obtained, and when the acid value is 150 mgKOH / g or less, the storage stability of the pixel portion (cured product of the ink composition) is easy to obtain. Is hard to decrease.

For the acid value of the polymer dispersant, prepare a sample solution prepared by dissolving the polymer dispersant pg in 50 mL of a mixed solution of toluene and ethanol in a volume ratio of 1: 1 and 1 mL of a phenolphthaline test solution. Titrate with a 1 mol / L ethanol potassium hydroxide solution (7.0 g of potassium hydroxide dissolved in 5.0 mL of distilled water and adjusted to 1000 mL by adding 95 vol% ethanol) until the sample solution turns pink. I do. Then, the acid value can be calculated by the following formula.
Acid value = q × r × 5.611 / p
In the formula, q indicates the titration amount (mL) of the 0.1 mol / L ethanol potassium hydroxide solution required for titration, and r indicates the titer of the 0.1 mol / L ethanol potassium hydroxide solution required for titration. Shown, p indicates the mass (g) of the polymer dispersant.

Polymer dispersants with basic functional groups have an amine value. The amine value of the polymer dispersant having a basic functional group is preferably 1 to 200 mgKOH / g. When the amine value is 1 mgKOH / g or more, sufficient dispersibility of the light-scattering particles can be easily obtained, and when the amine value is 200 mgKOH / g or less, the storage stability of the pixel portion (cured product of the ink composition) is easy to obtain. Is hard to decrease.

For the amine value of the polymer dispersant, prepare a sample solution prepared by dissolving xg of the polymer dispersant in 50 ml of a mixed solution of toluene and ethanol mixed at a volume ratio of 1: 1 and 1 ml of a bromophenol blue test solution. Titrate with 5 mol / L toluene until the sample solution turns green. Then, the amine value can be calculated by the following formula.
Amine value = y / x × 28.05
In the formula, y indicates the titration amount (ml) of 0.5 mol / L hydrochloric acid required for titration, and x indicates the mass (g) of the polymer dispersant.

The 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, polyamine such as polyethyleneimine and polyallylamine, epoxy resin, polyimide and the like. 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. The Efka series and the like can be used.

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

As the polymer dispersant, in addition to the commercially available products as described above, a cationic monomer containing a basic group and / or an anionic monomer having an acidic group, a monomer having a hydrophobic group, and other monomers as necessary. A product synthesized by copolymerizing with (a nonionic monomer, a monomer having a hydrophilic group, etc.) can be used. For details of the cationic monomer, the anionic monomer, the monomer having a hydrophobic group and other monomers, the monomers described in paragraphs 0034 to 0036 of JP-A-2004-250502 can be mentioned.

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

The weight average molecular weight of the polymer dispersant may be 750 or more, or even 1000 or more, from the viewpoint of being able to satisfactorily disperse light-scattering particles and improving the effect of reducing leakage light. It may be 2000 or more, or 3000 or more. The weight average molecular weight of the polymer dispersant can satisfactorily disperse light-scattering particles, improve the effect of reducing leakage light, and can eject the viscosity of inkjet ink, which is suitable for stable ejection. From this point of view, it may be 100,000 or less, 50,000 or less, or 30,000 or less.

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

Although each component contained in the ink composition of the present embodiment has been described above, the ink composition is a light-emitting nanocrystalline particle, an epoxy group-containing acrylic polymer, and a cured substance as long as the effect of the present invention is not impaired. It may further contain other components other than the agent, curing catalyst, light scattering particles, polymer dispersant and organic ligand. Examples of other components include solvents and the like.

Examples of the solvent include ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol dibutyl ether, diethyl adipate, dibutyl oxalate, dimethyl malonate, diethyl malonate, dimethyl succinate, and diethyl succinate. , 1,4-Butane odium diacetate, glyceryl triacetate and the like. It is preferable to use a solvent from the viewpoint of preparing the ink composition to be uniform and from the viewpoint of increasing the fluidity of the ink composition to form a color filter pixel portion (light conversion layer) with less unevenness.

The boiling point of the solvent is preferably 180 ° C. or higher from the viewpoint of continuous ejection stability of the inkjet ink. Further, since it is necessary to remove the solvent from the ink composition before curing the ink composition at the time of forming the pixel portion, the boiling point of the solvent is preferably 300 ° C. or lower from the viewpoint of easy removal of the solvent.

The above-mentioned ink composition can be applied as an ink used in a known and conventional method for producing a color filter, but it is necessary without wasting materials such as luminescent nanocrystal particles and a solvent, which are relatively expensive. It is preferable to appropriately prepare and use the color filter so as to be suitable for the inkjet method rather than the photolithography method in that the color filter pixel portion (optical conversion layer) can be formed only by using a necessary amount in various places.

The viscosity of the ink composition may be, for example, 2 mPa · s or more, 5 mPa · s or more, or 7 mPa · s or more from the viewpoint of ejection stability during inkjet printing. The viscosity of the ink composition may be 20 mPa · s or less, 15 mPa · s or less, or 12 mPa · s or less. When the viscosity of the ink composition is 2 mPa · s or more, the meniscus shape of the ink composition at the tip of the ink ejection hole of the ejection head is stable, so that the ejection control of the ink composition (for example, the ejection amount and the ejection timing) Control) becomes easy. On the other hand, when the viscosity is 20 mPa · s or less, the ink composition can be smoothly ejected from the ink ejection holes. The viscosity of the ink composition is 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, 2 to 20 mPa · s, 7 to 15 mPa · s, 7 to 12 mPa. It may be s or 7 to 12 mPa · s. The viscosity of the ink composition is measured, for example, by an E-type viscometer. The viscosity of the ink composition can be adjusted to a desired range by changing, for example, the weight average molecular weight of the epoxy group-containing acrylic polymer or the like, the content of the solvent, or the like.

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 this range, 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 less, the occurrence of flight bending can be suppressed. That is, a pixel portion may not be landed accurately on 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. The surface tension of the ink composition can be adjusted to a desired range by using, for example, a solvent composition, a fluorine-based surfactant, a silicone-based surface active agent, an acetylene-based surfactant, or the like in combination.

By the way, the step of forming the pixel portion using the conventional ink composition has been performed by a photolithography method, and the ink composition used in the photolithography method contains an alkali-soluble resin as a binder polymer. When the ink composition is used in a photography method, the ink composition is first applied onto a substrate, and when the ink composition contains a solvent, the ink composition is further dried to form a coating film. The coating film thus obtained is soluble in an alkaline developer and is patterned by being treated with an alkaline developer. At this time, 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. On the other hand, when the pixel portion is formed by the inkjet method using the ink composition of the present embodiment, it is not necessary to treat with an alkaline developer (aqueous solution), and the luminescence of the luminescent nanocrystal particles may be impaired by water. do not have.

Further, even when the coating film of the ink composition is not treated with an alkaline developer, when the ink composition is alkali-soluble, the coating film of the ink composition easily absorbs moisture in the atmosphere, and the time is long. As time passes, the luminescence (for example, fluorescence) of the 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 acrylic polymer as the acrylic polymer. 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, 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 after the ink composition is applied onto the substrate, it is dried at 80 ° C. for 3 minutes when it contains a solvent. It can be confirmed by measuring the above-mentioned dissolution amount of the obtained coating film having a thickness of 1 μm.

<Manufacturing method of ink composition>
Next, a method for producing the ink composition of the above-described embodiment will be described. The ink composition 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 of the method for producing an ink composition, a method for producing an ink composition further containing 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 the epoxy group-containing acrylic polymer, and the epoxy group-containing acrylic polymer may be further mixed in the second step. According to this method, the light scattering particles can be sufficiently dispersed. Therefore, the leakage light in the pixel portion can be reduced, and an ink composition having excellent ejection stability can be easily obtained.

In the step of preparing the dispersion of the light-scattering particles, the light-scattering particles, the polymer dispersant, and, in some cases, the epoxy group-containing acrylic polymer are mixed and subjected to the dispersion treatment to carry out the light-scattering particles. Dispersions may be prepared. The mixing and dispersion treatment may be performed using a dispersion device such as a bead mill, a paint conditioner, or a planetary stirrer. 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.

The method for producing an ink composition further comprises a step of preparing a dispersion of luminescent nanocrystal particles containing the luminescent nanocrystal particles and an epoxy group-containing acrylic polymer before the second step. May be. In this case, in the second step, the dispersion of the light-scattering particles and the dispersion of the luminescent nanocrystal particles are mixed. According to this method, the luminescent nanocrystal particles can be sufficiently dispersed. Therefore, the leakage light in the pixel portion can be reduced, and an ink composition having excellent ejection stability can be easily obtained. In the step of preparing the dispersion of the luminescent nanocrystal particles, the luminescent nanocrystal particles and the epoxy group-containing acrylic polymer are subjected to the same dispersion device as in the step of preparing the dispersion of the light-scattering particles. Mixing and dispersion processing may be performed.

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, deterioration of the luminescent nanocrystal particles is unlikely to occur, and the color filter pixel portion (light conversion layer) has the expected emission characteristics. Is easier to obtain.

<Optical conversion layer and color filter>
Next, the details of the light conversion layer and the color filter using the ink composition 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 each include a cured product of the ink composition of the above-described embodiment. The cured product contains luminescent nanocrystal particles, light-scattering particles, and a cured component. The curing component is a cured product of an epoxy group-containing acrylic polymer, and specifically, a cured product obtained by crosslinking the epoxy group-containing acrylic polymer. 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 pixel portion containing the cured product of the ink composition is 5% by mass or more based on the total mass of the cured product of the ink composition from the viewpoint of excellent effect of reducing leakage light. It may be 10% by mass or more, 15% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more. May be good. The content of the luminescent nanocrystal particles may be 70% by mass or less, or 60% by mass or less, based on the total mass of the cured product of the ink composition from the viewpoint of excellent reliability of the pixel portion. It may be 55% by mass or less, or 50% by mass or less.

The content of the light-scattering particles in the pixel portion containing the cured product of the ink composition is 0.1% by mass or more based on the total mass of the cured product of the ink composition from the viewpoint of excellent effect of reducing leakage light. It may be 1% by mass or more, 5% by mass or more, 7% by mass or more, 10% by mass or more, or 12% by mass or more. You may. The content of the light-scattering particles may be 60% by mass or less based on the total mass of the cured product of the ink composition from the viewpoint of excellent effect of reducing leakage light and excellent reliability of the pixel portion. It may be 50% by mass or less, 40% by mass or less, 30% by mass or less, 25% by mass or less, or 20% by mass or less. It may be 15% by mass or less.

The third pixel portion 10c has a transmittance of 30% or more with respect to light having a wavelength in the range of 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 third pixel portion 10c contains, for example, a cured product of a composition containing an epoxy group-containing acrylic polymer. The cured product contains a third cured component 13c. The third curing component 13c is a cured product obtained by crosslinking the epoxy group-containing acrylic polymer. That is, the third pixel portion 10c contains the third curing component 13c. When the third pixel portion 10c contains the above-mentioned cured product, the composition containing the epoxy group-containing acrylic polymer has a transmittance of 30% or more for light having a wavelength in the range of 420 to 480 nm. Among the components contained in the above-mentioned ink composition, components other than the epoxy group-containing acrylic polymer may be further contained. The transmittance of the third pixel unit 10c can be measured by a microspectroscopy device.

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 in which the binder polymer contains light-shielding particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments 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 two 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. In the method of forming the pixel portion by the conventional photolithography method, since development is usually performed using an alkaline developer, an alkali-soluble polymer is used as the binder polymer, and in principle, about two-thirds or more of the material is used. Will be removed, and the material will be wasted. As described above, the inkjet method is superior to the photolithography method in terms of material usage efficiency.

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 and the like.

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 heating temperature for curing the ink composition may be, for example, 110 ° C. or higher, and may be 250 ° C. or lower. The heating time may be, for example, 10 minutes or more and 120 minutes or less.

Although the color filter, the optical conversion layer, and one embodiment of these manufacturing methods have been described above, the 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.

For example, the optical conversion layer is a pixel portion containing a cured product of an ink composition containing blue-emitting nanocrystal particles in place of the third pixel portion 10c or in addition to the third pixel portion 10c ( It may be provided with a blue pixel portion). Further, the light conversion layer may include a pixel portion (for example, a yellow pixel portion) containing a cured product of an ink composition containing nanocrystal particles that emit light of a color other than red, green, and blue. 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 wettable variable layer is formed in a solid coating shape in a region including a pixel portion forming region, and then light is applied to the photocatalyst-containing layer via a photomask. Irradiation 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.

Further, the color filter may be provided with an ink receiving layer containing hydroxypropyl cellulose or 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 polymer is used as the binder polymer. 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, and the material is wasted. 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. For example, when a pixel portion containing luminescent nanocrystal particles that absorb and emit blue light is used as the pixel portion of the liquid crystal display element, the light from the light source is blue light or semi-white light having a peak at 450 nm. However, if the concentration of the luminescent nanocrystal particles in the pixel portion is not sufficient, the light from the light source passes through the light conversion layer when the liquid crystal display element is driven. The transmitted light (blue light, leaked light) from this light source and the light emitted by the luminescent nanocrystal particles are mixed. From the viewpoint of preventing deterioration of color reproducibility due to the occurrence of such color mixing, a pigment may be contained in the pixel portion of the optical conversion layer. In order to contain the pigment in the pixel portion, the pigment may be contained in the ink composition.

Further, one or two of 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 do not contain luminescent nanocrystal particles. It may be a pixel portion containing a coloring material. As the color material that can be used here, a known color material can be used. For example, examples of the coloring material used for the red pixel portion (R) include diketopyrrolopyrrole pigments and / or anionic red organic dyes. 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, 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 ε-type copper phthalosine pigments and / or cationic blue organic dyes. 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. All the materials used in the examples were those in which argon gas was introduced and the dissolved oxygen was replaced with nitrogen gas. As for titanium oxide, one which was heated at 120 ° C. for 2 hours under a reduced pressure of 1 mmHg and allowed to cool in an argon gas atmosphere was used before mixing. The liquid material used in the examples was dehydrated with Molecular Sieves 3A for 48 hours or more in advance before mixing.

<Preparation of indium laurate precursor 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 precursor solution). This precursor solution was kept in the glove box at room temperature until needed. Indium laurate has low solubility at room temperature and easily precipitates. Therefore, when using a precursor solution, the precipitated indium laurate in the precursor solution (ODE mixture) is heated to about 90 ° C to become transparent. After forming the solution, the desired amount was weighed and used.

<Synthesis of green light emitting core / shell nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles)>
[Synthesis of InP core for green light emitting core / shell nanocrystal particles]
5 g of trioctylphosphine oxide (TOPO), 2.33 g (8 mmol) of indium acetate and 4.797 g (24 mmol) of lauric acid were added to the reaction flask to obtain a mixture. Under vacuum, the mixture was heated at 160 ° C. for 40 minutes and then at 250 ° C. for 20 minutes. 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 trioctylphosphine (TOP) and 1 g (4 mmol) of tris (trimethylsilyl) phosphine was rapidly introduced into the reaction flask and the reaction temperature was maintained at 260 ° C. After 1 minute, the reaction was stopped by removing the heater, and the obtained reaction solution was cooled to room temperature. Then 8 ml of toluene and 25 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 nanocrystals were dispersed in hexane.

[Indium reinforced InP core and synthesis of ZnSeS / ZnS shell]
A hexane solution of InP nanocrystal particles, 6 ml of ODE, and an indium phosphide precursor solution prepared above were added to a reaction flask to obtain a mixture. The amount of the InP core added in the hexane solution and the precursor solution was adjusted so that the amount of the InP core was 25 mg and that of the indium phosphide was 5 g. After allowing the mixture to stand at room temperature for 10 minutes under vacuum, the temperature of the mixture was raised to 230 ° C. and kept at that temperature for 2 hours.

Then, the reaction temperature (temperature of the mixture) was lowered to 140 ° C., 0.7 g of oleic acid was added to the reaction flask, and the mixture was kept at 140 ° C. for 10 minutes. Then, 21 mg of diethylzinc dissolved in 1 ml of ODE, 13 mg of bis (trimethylsilyl) selenide and 10 mg of hexamethyldisyltian (ZnSeS) were added dropwise to the reaction mixture to form a ZnSSe shell having a thickness of 0.5 monolayer. Formed.

After dropping the ZnSeS precursor solution, the reaction temperature was maintained at 140 ° C. for 30 minutes. Then, 110 mg of diethylzinc and 106 mg of hexamethyldisyltian (ZnS precursor solution) dissolved in 2 ml of ODE were added dropwise to this reaction mixture to form a ZnS shell having a thickness of 2 monolayers. After 10 minutes of dropping the ZnS precursor solution, the reaction was stopped by removing the heater. The reaction mixture was then cooled to room temperature and the resulting white precipitate was removed by centrifugation to provide a clear green luminescent nanocrystal particle solution (ODE) in which green luminescent InP / ZnSeS / ZnS nanoparticles were dispersed. Solution) was obtained.

<Synthesis of red light emitting core / shell nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles)>
[Synthesis of InP core for red light emitting core / shell nanocrystal particles]
[Synthesis of red light emitting nanocrystal particle core (InP core)]
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 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 obtained 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.

[Indium reinforced InP core and synthesis of ZnSeS / ZnS shell]
A hexane solution of InP nanocrystal particles (InP core) and an indium phosphide precursor solution were added to the reaction flask to obtain a mixture. The amount of the InP core added in the hexane solution and the precursor solution was adjusted so that the amount of the InP core was 25 mg and that of the indium phosphide was 5 g. After allowing the mixture to stand at room temperature for 10 minutes under vacuum, the temperature of the mixture was raised to 230 ° C. and kept at that temperature for 2 hours.

Then, the reaction temperature (temperature of the mixture) was lowered to room temperature, 0.7 g of oleic acid was added to the reaction flask, and the temperature was raised to 80 ° C. Then, 14 mg of diethylzinc, 8 mg of bis (trimethylsilyl) selenide and 7 mg of hexamethyldisyltian (ZnSeS precursor solution) dissolved in 1 ml of ODE were added dropwise to the reaction mixture to obtain a thickness of 0.5 monolayer. A ZnSeS shell was formed.

After dropping the ZnSeS precursor solution, the reaction temperature was maintained at 80 ° C. for 10 minutes. The temperature was then raised to 140 ° C. and held for 30 minutes. Next, 69 mg of diethylzinc and 66 mg of hexamethyldisyltian (ZnS precursor solution) dissolved in 2 mL of ODE were added dropwise to this reaction mixture to form a ZnS shell having a thickness of 2 monolayers. After 10 minutes of dropping the ZnS precursor solution, the reaction was stopped by removing the heater. The reaction mixture was then cooled to room temperature and the resulting white precipitate was removed by centrifugation to provide a clear red luminescent nanocrystal particle solution (ODE) in which red luminescent InP / ZnSeS / ZnS nanoparticles were dispersed. Solution) was obtained.

<Ligand synthesis>
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 a ligand represented by the following formula (1A) as a pale yellow viscous oil.

<Preparation of InP / ZnSeS / ZnS nanocrystal particle dispersion by ligand exchange>
30-50 mg of the ligand obtained above was added to 1 ml of the green luminescent nanocrystal particle solution obtained above. Then, the ligand was exchanged by heating at 90 ° C. for 3 to 15 hours. 6 ml of ethanol was added to 1 ml of the nanocrystal particle solution after ligand exchange. Subsequently, centrifugation is performed to precipitate the nanocrystal particles, and then the nanocrystal particles (InP / ZnSeS / ZnS nanos modified with a ligand represented by the above formula (1A)) are subjected to tilting of the supernatant and drying under vacuum. Crystal particles) were obtained. By dispersing the obtained nanocrystal particles in 1,4-BDDA (1,4-butanediol diacetate, manufactured by Daicel Corporation) so that the non-volatile content is 30 wt%, green light emitting core / shell nanocrystal particles A dispersion (1,4-BDDA dispersion) was obtained. Further, a red light emitting core / shell nanocrystal particle dispersion (1,4-BDDA dispersion) was obtained in the same manner as above except that the red light emitting nanocrystal particle solution was used instead of the green light emitting nanocrystal particle solution. rice field.

<Preparation of light-scattering particle dispersion>
In a container filled with argon gas, 2.4 g of titanium oxide (trade name: MPT141, manufactured by Ishihara Sangyo Co., Ltd.) and a polymer dispersant (trade name: DISPERBYK-2164, manufactured by BYK, "DISPERBYK" are registered. 0.4 g of (Trademark) and 1,4-BDDA were mixed to prepare a mixed solution having a non-volatile content of 44%. After adding zirconia beads (diameter: 1.25 mm) to the mixed solution in the container filled with argon gas, the closed container filled with argon gas is shaken for 2 hours using a paint conditioner to disperse the mixed solution. Was done. The light-scattering particle dispersion 1 was obtained by removing the zirconia beads with a polyester mesh filter.

<Preparation of acrylic polymer solution>
[Preparation of acrylic polymer solution 1]
FINEDIC A-254 (manufactured by DIC Co., Ltd., epoxy equivalent 535 g / eq), which is an acrylic polymer, is 0.303 g, and 1-methylcyclohexane-4,5-dicarboxylic acid anhydride, which is a curing agent, is used (Tokyo Kasei Kogyo Co., Ltd.). 0.095 g of (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 0.0021 g of dimethylbenzylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a curing catalyst, 1,4-butanediol diacetate so as to have a non-volatile content of 50%. To obtain 0.8 g of the acrylic polymer solution 1 was obtained.

[Preparation of acrylic polymer solution 2]
The acrylic polymer FINEDIC A-272 (manufactured by DIC Co., Ltd., epoxy equivalent 335 g / eq) was 0.266 g, and the curing agent 1-methylcyclohexane-4,5-dicarboxylic acid anhydride (Tokyo Kasei Kogyo). 0.087 g of (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 0.0019 g of dimethylbenzylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a curing catalyst, 1,4-butanediol diacetate so as to have a non-volatile content of 50%. To obtain 0.8 g of the acrylic polymer solution 2.

[Preparation of acrylic polymer solution 3]
The acrylic polymer FINEDIC A-247S (manufactured by DIC Co., Ltd., epoxy equivalent 600 g / eq) is 0.311 g, and the curing agent 1-methylcyclohexane-4,5-dicarboxylic acid anhydride (Tokyo Kasei Kogyo). 0.087 g of (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 0.0019 g of dimethylbenzylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a curing catalyst, 1,4-butanediol diacetate so as to have a non-volatile content of 50%. To obtain 0.8 g of the acrylic polymer solution 3 was obtained.

<Example 1>
[Preparation of ink composition (inkjet ink)]
2.40 g of green light emitting core / shell nanocrystal particle dispersion (solid content concentration 30% by mass), 0.8 g of light scattering particle dispersion 1, 0.8 g of acrylic polymer solution 1 and argon. After uniform mixing in a gas-filled container, 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 obtaining argon gas, and the inside of the container was saturated with argon gas. Then, the pressure was reduced to remove the argon gas to obtain an ink composition.

[Preparation of sample for evaluation]
The ink composition obtained above was applied onto a glass substrate in the atmosphere with a spin coater so that the film thickness after drying was 3 μm. The coating film was heated and cured at 180 ° C. under a nitrogen atmosphere to form a layer (light conversion layer) made of a cured product of the ink composition on a glass substrate. By the above operation, an evaluation sample 1 was obtained.

[Measurement of external quantum efficiency (EQE)]
The external quantum efficiency (EQE) was measured by the following method. That is, a blue LED (peak emission wavelength: 450 nm) manufactured by CCS Inc. was used as the surface emission light source. An integrating sphere connected to a radiation spectrophotometer (trade name: MCPD-9800) manufactured by Otsuka Electronics Co., Ltd. was installed above the blue LED. The evaluation sample 1 was inserted between the blue LED and the integrating sphere, and the spectrum observed by turning on the blue LED and the illuminance at each wavelength were measured. The external quantum efficiency (EQE) was determined as follows from the spectrum and illuminance measured by the above measuring device. This value is a value indicating how much of the light (photons) incident on the optical conversion layer is emitted to the observer side as fluorescence. Therefore, if this value is large, it indicates that the optical conversion layer is excellent, and it is an important evaluation index.
External quantum efficiency of red emission light conversion layer = P (Red) / E (Blue) × 100 (%)
External quantum efficiency of green emission light conversion layer = P (Green) / E (Blue) x 100 (%)

Here, E (Blue), P (Red), and P (Green) represent the following, respectively.
E (Blue):
It represents the total value of "illuminance x wavelength ÷ hc" in the wavelength range of 380 to 490 nm (or 380 to 500 nm) in this wavelength range (this is a value corresponding to the number of observed photons). In addition, h represents Planck's constant and c represents the speed of light.
P (Green):
It represents the total value of "illuminance x wavelength ÷ hc" in the measurement wavelength of 490 to 590 nm in this wavelength range (corresponding to the number of observed photons).
P (Red):
It represents the total value of "illuminance x wavelength ÷ hc" in this wavelength range at the measurement wavelength of 590 to 780 nm (corresponding to the number of observed photons).

[Evaluation of external quantum efficiency maintenance rate]
The maintenance rate of the external quantum efficiency (EQE) was determined by measuring the EQE before and after allowing the evaluation sample 1 to stand in an air atmosphere for 3 weeks at room temperature, respectively, according to the following formula.
External quantum efficiency maintenance rate (%) = EQE ₁ / EQE ₀ x 100
Here, EQE ₀ is the external quantum efficiency before standing still, and EQE ₁ is the external quantum efficiency after standing still.

<Examples 2 to 3 and Comparative Example 1>
The red light emitting core / shell nanocrystal particle dispersion was used instead of the green light emitting core / shell nanocrystal particle dispersion, and the acrylic polymer solutions 2 to 3 were used instead of the acrylic polymer solution 1. The ink compositions of Examples 2 to 3 and Comparative Example 1 were obtained in the same manner as in Example 1 except for the above. Using the obtained ink composition, the external quantum efficiency maintenance rate was measured in the same manner as in Example 1. The results are shown in Table 1.

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, 20 ... light-shielding part, 30 ... light conversion layer, 40 ... base material, 100 ... color filter.

Claims (16)

Containing luminescent nanocrystal particles and an acrylic polymer,
The acrylic polymer has an epoxy group, and the epoxy equivalent of the acrylic polymer is less than 560 g / eq .
An ink composition in which the acrylic polymer is alkali-insoluble . The ink composition according to claim 1, further comprising light-scattering particles. The ink composition according to claim 2, wherein the light-scattering particles have an average particle size of 0.05 to 1.0 μm. The ink composition according to claim 2 or 3, wherein the light-scattering particles include at least one selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate and silica. The ink composition according to any one of claims 1 to 4, further comprising a polymer dispersant. The ink composition according to claim 5, wherein the polymer dispersant has a weight average molecular weight of 1000 or more. The ink composition according to any one of claims 1 to 6 , wherein an alkali-insoluble coating film can be formed. The ink composition according to any one of claims 1 to 7 , wherein the surface tension is 20 to 40 mN / m. The ink composition according to any one of claims 1 to 8 , which has a viscosity of 2 to 20 mPa · s. The ink composition according to any one of claims 1 to 9 , further comprising a solvent having a boiling point of 180 ° C. or higher. The ink composition according to any one of claims 1 to 10 , which is used for a color filter. The ink composition according to any one of claims 1 to 11 , which is used in an inkjet method. An optical conversion layer having a plurality of pixel portions.
The plurality of pixel portions are optical conversion layers having pixel portions containing a cured product of the ink composition according to any one of claims 1 to 11 . Further, a light-shielding portion provided between the plurality of pixel portions is further provided.
The plurality of pixel portions are
The cured product is contained, and the luminescent nanocrystal particles include 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. , The first pixel part,
The cured product is contained, and the luminescent nanocrystal particles include 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. , The second pixel part,
13. The optical conversion layer according to claim 13 . The optical conversion layer according to claim 14 , further comprising a third pixel portion having a transmittance of 30% or more with respect to light having a wavelength in the range of 420 to 480 nm. A color filter comprising the optical conversion layer according to any one of claims 13 to 15 .

Images