JP7087797B2 - 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 required. A method of forming a color filter pixel portion such as a red pixel and a green pixel by using the above is being actively studied.

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

International Publication No. 2008/001693

The ink composition used in the inkjet method is required to be stable over time. In particular, since the viscosity of the ink composition is an important property for suitably forming the pixel portion of the optical conversion substrate by the inkjet method, when the viscosity of the ink composition increases with time, a desired pixel portion of the optical conversion substrate is formed. It may not be possible.

Therefore, an object of the present invention is to suppress an increase in the viscosity of the ink composition over time.

One aspect of the present invention has a bicyclo structure containing luminescent nanocrystalline particles, an epoxy resin, and an acid anhydride-based curing agent, wherein the acid anhydride-based curing agent shares at least three carbon atoms. , With respect to the ink composition. In this ink composition, an increase in viscosity with time is suppressed, particularly by using an acid anhydride-based curing agent having a bicyclo structure sharing at least three carbon atoms.

The ink composition may further contain light scattering particles. The ink composition may further contain a curing accelerator selected from phosphonium salts. The ink composition may further contain a solvent having a boiling point of 180 ° C. or higher.

The viscosity of the ink composition at 25 ° C. may be 2 to 20 mPa · s. The content of the non-volatile component may be 35% by mass or more based on the total mass of the ink composition. The surface tension of the ink composition may be 20-40 mN / m.

The ink composition may be for a color filter. The ink composition may be an ink composition (inkjet ink) used in an inkjet method.

Another 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.

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. A first pixel portion containing luminescent nanocrystal particles that absorb the light of the above and emit light having a emission peak wavelength in the range of 605 to 665 nm, and the cured product, and as luminescent nanocrystal particles. A plurality of pixels comprising 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 unit may further include a third pixel unit having a transmission rate of 30% or more for light having a wavelength in the range of 420 to 480 nm.

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

According to the present invention, it is possible to suppress an increase in the viscosity of the ink composition over time.

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, an epoxy resin, and an acid anhydride-based curing agent. This ink composition is an ink composition for a color filter used for forming a pixel portion of a color filter by a method such as a photolithography method or an inkjet method.

The ink composition of the embodiment can be applied as an ink used in a known and conventional method for producing a color filter, but without wastefully consuming materials such as luminescent nanocrystalline 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 the necessary amount in the necessary place. .. That is, the ink composition of the embodiment is suitably used for forming a color filter pixel portion by an inkjet method.

Hereinafter, an ink composition for a color filter (inkprint ink for a color filter) used in an inkjet method, which contains luminescent nanocrystal particles, an epoxy resin, and an acid anhydride-based curing agent, will be described as an example. ..

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

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

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

Green luminescent nanocrystal particles have emission peak wavelengths of 560 nm or less, 557 nm or less, 555 nm or less, 550 nm or less, 547 nm or less, 545 nm or less, 543 nm or less, 540 nm or less, 537 nm or less, 535 nm or less, 532 nm or less, or 530 nm or less. It is preferable to have an emission peak wavelength of 528 nm or more, 525 nm or more, 523 nm or more, 520 nm or more, 515 nm or more, 510 nm or more, 507 nm or more, 505 nm or more, 503 nm or more, or 500 nm or more.

Blue luminescent nanocrystal particles have emission peak wavelengths of 480 nm or less, 477 nm or less, 475 nm or less, 470 nm or less, 467 nm or less, 465 nm or less, 463 nm or less, 460 nm or less, 457 nm or less, 455 nm or less, 452 nm or less, or 450 nm or less. It is preferable to have an emission peak wavelength of 450 nm or more, 445 nm or more, 440 nm or more, 435 nm or more, 430 nm or more, 428 nm or more, 425 nm or more, 422 nm or more, or 420 nm or more.

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

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

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

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

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

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

The blue light emitting semiconductor nanocrystal particles include, for example, ZnSe nanocrystal particles, ZnS nanocrystal particles, and nanocrystal particles having a core / shell structure, and the shell portion is ZnSe and the inner core portion. Is ZnS nanocrystal particles, CdS nanocrystal particles, nanocrystal particles having a core / shell structure, and the shell portion is ZnS and the inner core portion is InP nanocrystal particles, core / shell. Nano-crystal particles having a structure, the shell portion of which is a mixed crystal of ZnS and ZnSe and the inner core portion of which is InP, and the nano-crystal particles having a core / shell / shell structure. The first shell portion is ZnSe, the second shell portion is ZnS, the inner core portion is InP, and the nanocrystal particles have a core / shell / shell structure. Examples thereof include nano-crystal particles in which the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and the inner core portion is InP. The semiconductor nanocrystal particles have the same chemical composition, and by changing the average particle size of the particles themselves, the color to be emitted from the particles can be changed to red or green. Further, it is preferable to use semiconductor nanocrystal particles as such, which have as little adverse effect on the human body as possible. When semiconductor nanocrystal particles containing cadmium, selenium, etc. are used as luminescent nanocrystal particles, semiconductor nanocrystal particles containing the above elements (cadmium, selenium, etc.) as little as possible are selected and used alone, or the above elements. It is preferable to use it in combination with other luminescent nanocrystal particles so that the amount of cadmium is as small as possible.

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

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

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.

The organic ligand includes a functional group for ensuring affinity with an epoxy resin, an organic solvent, etc. (hereinafter, also simply referred to as "affinity group"), and a functional group capable of binding to luminescent nanocrystal particles (emission). It is preferable that the compound has (functional group) for ensuring the adsorptivity to the sex nanocrystal particles. The affinity group may be a substituted or unsubstituted aliphatic hydrocarbon group. 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. The substituted aliphatic hydrocarbon may be a group in which some carbon atoms of the aliphatic hydrocarbon group are substituted with oxygen atoms. The substituted aliphatic hydrocarbon group may contain, for example, a (poly) oxyalkylene group. Here, the "(poly) oxyalkylene group" means at least one of an oxyalkylene group and a polyoxyalkylene group in which two or more alkylene groups are linked by an ether bond. Examples of the functional group that can be bonded to the luminescent nanocrystal particle include a hydroxyl group, an amino group, a carboxyl group, a thiol group, a phosphoric acid group, a phosphonic acid group, a phosphine group, a phosphine oxide group, and an alkoxysilyl group. 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 octylphosphic acid (OPA).

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

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

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

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

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

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

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

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

式（１－２Ａ）中、ｒは上記と同義である。 The organic ligand is preferably an organic ligand represented by the following formula (1-2A).

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

The organic ligand is preferably an organic ligand represented by the formula (1-2A) from the viewpoint of the heat resistance of the external quantum yield of the ink composition and the external quantum yield of the cured product of the ink composition.

As the luminescent nanocrystal particles, those dispersed in a colloidal form in an organic solvent, a photopolymerizable compound, or the like can be used. The surface of the luminescent nanocrystal particles dispersed in the organic solvent is preferably passivated by the above-mentioned organic ligand. Examples of the organic solvent include cyclohexane, hexane, heptane, chloroform, toluene, octane, chlorobenzene, tetralin, diphenyl ether, propylene glycol monomethyl ether acetate, butyl carbitol acetate, 1,4-butanediol diacetate, or a mixture thereof. Can be mentioned.

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

The content of the luminescent nanocrystal particles may be 5% by mass or more, even if it is 10% by mass or more, based on the mass of the non-volatile content of the ink composition, from the viewpoint of being more excellent in the effect of improving the external quantum efficiency. It may be 15% by mass or more, 20% by mass or more, or 25% by mass or more. When the content of the luminescent nanocrystal particles is 5% by mass or more, excellent luminescence intensity can be obtained, so that such an ink composition is suitably used for color filter applications. From the same viewpoint, the content of the luminescent nanocrystal particles may be 50% by mass or less, 40% by mass or less, or 35% by mass or less, based on the mass of the non-volatile content of the ink composition. It may be 30% by mass or less. The content of the luminescent nanocrystal particles is 50% by mass or less based on the mass of the non-volatile content of the ink composition from the viewpoint of being more excellent in ejection stability. Further, when the content of the luminescent nanocrystal particles is 50% by mass or less, excellent luminescence intensity can be obtained, so such an ink composition is suitably used for color filter applications. From the same viewpoint, the content of the luminescent nanocrystal particles may be 40% by mass or less, 35% by mass or less, or 30% by mass, based on the mass of the non-volatile content of the ink composition. It may be as follows. The content of the luminescent nanocrystal particles is 5 to 50% by mass, 10 to 50% by mass, 15 to 40% by mass, 15 to 35% by mass, and 20 to 35% by mass based on the mass of the non-volatile content of the ink composition. It may be% or 20 to 30% by mass.

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. In the absence of solvent, it refers to the total mass of the ink composition. The content of the non-volatile content is 30% by mass or more, 35% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass based on the total mass of the ink composition. It may be 90% by mass or more, or 100% by mass.

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

[Epoxy resin]
The epoxy resin has at least one epoxy group in one molecule, and preferably has two or more epoxy groups in one molecule. The epoxy resin may be, for example, a condensate of a compound having two or more active hydrogens and epichlorohydrin, an oxide of an olefin, or the like. The condensate may be a glycidyl ether type epoxy resin, a glycidyl amine type epoxy resin, a glycidyl ester type epoxy resin, or the like, and is preferably a glycidyl ether type epoxy resin. The glycidyl ether type epoxy resin is preferably a condensate of epichlorohydrin and a compound having two or more hydroxyl groups such as bisphenol A, bisphenol F, and novolak.

The epoxy resin does not have to contain a monomer having a (meth) acryloyl group ((meth) acrylic monomer) as a monomer unit. In addition, in this specification, "(meth) acryloyl group" means "acryloyl group" and the corresponding "methacryloyl group".

The epoxy resin may be, for example, a compound represented by the following formula (2).

In the formula (2), X represents an n-valent organic group having an aromatic ring, and n represents an integer of 2 or more. X may have at least one selected from the group consisting of a benzene ring and a naphthalene ring, and preferably has a benzene ring. These aromatic rings may or may not have a substituent.

The epoxy resin represented by the formula (2) may be, for example, a compound represented by the following formula (3).

In formula (3), Y ¹ represents a divalent organic group having an aromatic ring, and n ¹ represents an integer of 0 or more. Y ¹ may have at least one selected from the group consisting of a benzene ring and a naphthalene ring, and preferably has a benzene ring. These aromatic rings may or may not have a substituent. A plurality of Y ^1s may be the same as each other or may be different from each other. n ¹ may be, for example, an integer of 0 to 10.

The epoxy resin represented by the formula (3) is preferably a compound represented by the following formula (3A).

In formula (3A), R ¹ represents a monovalent hydrocarbon group, Z ¹ represents a single bond, an alkylene group, an alkylidene group, a cycloalkylene group, and a bicycloalkylene group, and n ^1A is an integer of 0 or more. ^1A indicates an integer of 0 to 4. The plurality of R ¹ , Z ¹ , and m ^1A that exist may be the same as each other or may be different from each other. R ¹ may be, for example, an alkyl group, a cycloalkyl group, a bicycloalkyl group, or an aryl group. The number of carbon atoms of the hydrocarbon group represented by R ¹ may be, for example, 1 to 10. The carbon number of the alkylene group represented by Z ¹ may be, for example, 1 to 10. The carbon number of the alkylidene group represented by Z ¹ may be, for example, 2 to 10. The number of carbon atoms of the cycloalkylene group represented by Z ¹ may be, for example, 5 to 10. The number of carbon atoms of the bicycloalkylene group represented by Z ¹ may be, for example, 8 to 14.

The epoxy resin represented by the formula (2) may be, for example, a compound represented by the following formula (4).

In formula (4), Y ² represents a divalent organic group having an aromatic ring, and n ² represents an integer of 0 or more. Y ² may have at least one selected from the group consisting of a benzene ring and a naphthalene ring, and preferably has a benzene ring. These aromatic rings may or may not have a substituent. A plurality of Y ^2s existing may be the same as each other or may be different from each other. n ² may be, for example, an integer of 0 to 20.

The epoxy resin represented by the formula (4) is preferably a compound represented by the following formula (4A).

In formula (4A), R ² represents a monovalent hydrocarbon group, Z ² represents a single bond, an alkylene group, an alkylidene group, a cycloalkylene group, and a bicycloalkylene group, and n ^2A is an integer of 0 or more. ^2A indicates an integer of 0 to 4. A plurality of R ² , Z ² and m ^2A may be the same as each other or may be different from each other. R ² may be, for example, an alkyl group, a cycloalkyl group, a bicycloalkyl group, or an aryl group. The number of carbon atoms of the hydrocarbon group represented by ^R2 may be, for example, 1 to 10. The carbon number of the alkylene group represented by Z ² may be, for example, 1 to 10. The carbon number of the alkylidene group represented by Z ² may be, for example, 2 to 10. The carbon number of the cycloalkylene group represented by Z ² may be, for example, 5 to 10. The number of carbon atoms of the bicycloalkylene group represented by Z ¹ may be, for example, 8 to 14.

As the epoxy resin, one kind of epoxy resin may be used alone, or a plurality of epoxy resins may be used in combination.

Specific examples of the epoxy resin include, for example, "EPICLON 860" (trade name, manufactured by DIC Corporation), "EPICLON 1050" (trade name, manufactured by DIC Corporation), and "EPICLON 3050" (trade name, manufactured by DIC Corporation). ), "EPICLON 7050" (trade name, manufactured by DIC Corporation), "EPICLON HM-091" (trade name, manufactured by DIC Corporation), etc. Bisphenol A type liquid epoxy resin such as "EPICLON EXA-850CRP" (trade name, manufactured by DIC Corporation), modified novolak type such as "EPICLON N-865" (trade name, manufactured by DIC Corporation) Epoxy resins, naphthalene-type epoxy resins such as "EPICLON HP-4032D" (trade name, manufactured by DIC Corporation), flexible tough epoxy resins such as "EPICLON EXA-4850-150" (trade name, manufactured by DIC Corporation) Can be mentioned.

The epoxy resin may be alkali-insoluble from the viewpoint that a color filter pixel portion having excellent reliability can be easily obtained. In the present specification, the epoxy resin is alkaline insoluble means that the amount of the epoxy resin dissolved in 1% by mass of a potassium hydroxide aqueous solution at 25 ° C. is 30% by mass or less based on the total mass of the epoxy resin. Means. The dissolved amount of the epoxy resin is preferably 10% by mass or less, and more preferably 3% by mass or less.

The content of the epoxy resin is from the viewpoint that an appropriate viscosity can be easily obtained as an inkjet ink, from the viewpoint of improving the curability of the ink composition, and the solvent resistance and polishing resistance of the pixel portion (cured product of the ink composition). From the viewpoint of improving the wear resistance, it may be 10% by mass or more, 15% by mass or more, or 20% by mass or more based on the mass of the non-volatile content of the ink composition. The content of the epoxy resin is based on the mass of the non-volatile content of the ink composition from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink and from the viewpoint of obtaining better optical characteristics (for example, external quantum efficiency). 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.

[Acid anhydride-based curing agent]
The acid anhydride-based curing agent has a bicyclo structure. The bicyclo structure may be a ring structure composed of only carbon atoms. The two rings in the bicyclo structure share at least three carbon atoms among the carbon atoms constituting the ring, and may share 3 to 5 carbon atoms or 3 to 4 carbon atoms. Two carbon atoms may be shared. The bicyclo structure may have a carbon-carbon double bond.

The bicyclo structure is, for example, a structure represented by the following formula (Ia) or (Ib).

The acid anhydride-based curing agent is, for example, a compound represented by the following formula (IIa) or (IIb).

In the formula, R ¹¹ to R ¹⁴ each independently represent a hydrogen atom or an alkyl group. The number of carbon atoms of the alkyl group may be 1 or more, and may be 4 or less, 3 or less, or 2 or less. The alkyl group may be a methyl group. At least one of R ¹¹ to R ¹⁴ may be a methyl group, any one of R ¹¹ to R ¹⁴ may be a methyl group, the rest may be a hydrogen atom, and one of R ¹² and R ¹³ may be. It is a methyl group, and the other of R ¹² and R ¹³ and R ¹¹ and R ¹⁴ may be hydrogen atoms.

Examples of the acid anhydride-based curing agent include bicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride, methylbicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride, and methyl-. Examples thereof include 3,6 endomethylene-1,2,3,6-tetrahydrohydride phthalic acid and 3,6 endomethylene-1,2,3,6-tetrahydrohydride phthalic acid.

The content of the acid anhydride-based curing agent may be, for example, 1% by mass or more, 5% by mass or more, or 10% by mass or more, and 40% by mass or less, based on the mass of the non-volatile content of the ink composition. It may be 35% by mass or less, or 30% by mass or less.

The ink composition may further contain a curing accelerator. The curing accelerator may be, for example, a phosphorus-based compound, a tertiary amine compound, an imidazole compound, an organic acid metal salt, a Lewis acid, an amine complex salt, or the like, and is preferably selected from a tertiary amine compound and a phosphorus-based compound. .. The tertiary amine compound is, for example, 1,8-diazabicyclo (5,4,0) undecene-7, 1,5-diazabicyclo (4,3,0) nonene-5, tris (dimethylaminomethyl) phenol, N. , N-dimethylbenzylamine and the like.

The curing accelerator is preferably selected from phosphorus compounds from the viewpoint of further suppressing an increase in the viscosity of the ink composition over time. The phosphorus-based compound may be, for example, a phosphine compound, a phosphonium salt, or the like. The phosphine compound may be, for example, triphenylphosphine, triparatolylphosphine, diphenylcyclohexylphosphine or the like.

The curing accelerator is preferably selected from the phosphonium salt from the viewpoint of further suppressing an increase in the viscosity of the ink composition over time. The phosphonium salt is composed of a phosphonium cation and its counter anion, and is represented by, for example, the following formula (III).

In the formula, R ²¹ to R ²⁴ independently represent an alkyl group or an aryl group, and A ⁻ represents a counter anion. The number of carbon atoms of the alkyl group represented by R ²¹ to R ²⁴ may be 1 or more, and may be 8 or less, 6 or less, 4 or less, 3 or less, or 2 or less. The aryl group represented by R ²¹ to R ²⁴ may have 6 or more carbon atoms, and may have 12 or less, 10 or less, 9 or less, 8 or less, or 7 or less. In one embodiment, R ²¹ to R ²⁴ may all be alkyl groups, R ²¹ to R ²³ may be the same alkyl group as each other, and R ²⁴ may be an alkyl group different from R ²¹ to R ²³ . , R ²¹ to R ²³ may be a butyl group, and R ²⁴ may be a methyl group.

A ⁻ may be an anion containing a phosphorus atom, an anion containing a boron atom, an anion containing a nitrogen atom, or the like, and the phosphorus atom is preferably used from the viewpoint of further suppressing an increase in the viscosity of the ink composition over time. It is an anion containing.

式中、Ｒ^３１及びＲ^３２は、それぞれ独立して、アルキル基又はアリール基を表す。Ｒ^３１及びＲ^３２で表されるアルキル基の炭素数は、１以上であってよく、８以下、６以下、４以下、３以下、又は２以下であってよい。Ｒ^２１～Ｒ^２４で表されるアリール基の炭素数は、６以上であってよく、１２以下、１０以下、９以下、８以下、又は７以下であってよい。Ｒ^３１及びＲ^３２は、一実施形態において、いずれもアルキル基であってよく、いずれもメチル基であってよい。 The anion containing a phosphorus atom is preferably represented by the following formula (IV) from the viewpoint of further suppressing an increase in the viscosity of the ink composition with time.

In the formula, R ³¹ and R ³² independently represent an alkyl group or an aryl group, respectively. The number of carbon atoms of the alkyl group represented by R ³¹ and R ³² may be 1 or more, and may be 8 or less, 6 or less, 4 or less, 3 or less, or 2 or less. The aryl group represented by R ²¹ to R ²⁴ may have 6 or more carbon atoms, and may have 12 or less, 10 or less, 9 or less, 8 or less, or 7 or less. In one embodiment, R ³¹ and R ³² may both be an alkyl group and may be a methyl group.

The content of the curing agent accelerator may be, for example, 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more based on the mass of the non-volatile content of the ink composition. It may be 0% by mass or less, 7% by mass or less, or 5% by mass or less.

Although each component contained in the ink composition of the present embodiment has been described above, the ink composition of the present embodiment may further contain components (other components) other than the above. Examples of other components include light-scattering particles, polymer dispersants, solvents and the like.

[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 metals such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum and gold; silica, barium sulfate, barium carbonate, calcium carbonate, etc. Metal oxides such as talc, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, alumina white, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, zinc oxide; magnesium carbonate, barium carbonate, Metallic carbonates such as secondary bismuth carbonate and calcium carbonate; Metal hydroxides such as aluminum hydroxide; Composite oxides such as barium zirconate, calcium zirconate, calcium titanate, barium titanate and strontium titanate, bismuth hyponitrate Such as metal salts and the like. The light-scattering particles are from the group consisting of titanium oxide, alumina, zinc oxide, zinc oxide, calcium carbonate, barium sulfate, barium titanate, and silica from the viewpoint of excellent ejection stability and the effect of improving external quantum efficiency. It is preferable to contain at least one selected, and more preferably to contain at least one selected from the group consisting of titanium oxide, zinc oxide, zinc oxide and barium titanate.

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

The light-scattering particles may be those in which at least a part of the surface is covered with alumina. Of the surface of the light-scattering particles, for example, 50 area% or more may be covered with alumina, and the entire surface of the light-scattering particles may be covered with alumina. In this case, the light-scattering particles can be rephrased as light-scattering particles surface-treated with alumina.

As a method of covering at least a part of the surface of the light-scattering particles with alumina (surface treatment with alumina), for example, a wet treatment method (adding an aqueous aluminum salt solution to the light-scattering particle slurry to neutralize the solution). A method of adsorbing on the surface of light-scattering particles). Examples of light-scattering particles include "MPT-141", "CR-50", "CR-50-2", "CR-58", "CR-58-2", and "CR" manufactured by Ishihara Sangyo Co., Ltd. It is also possible to use commercially available products such as "-60", "CR-60-2", "JR405", "JR603", "JR605", "JR701", and "JR806" manufactured by Teika Co., Ltd. The surface of the light-scattering particles may be covered with alumina and other components such as silica, zinc oxide, titanium oxide, zirconium oxide, and organic substances such as stearic acid and polysiloxane.

The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition may be 0.05 μm or more from the viewpoint of excellent ejection stability and the effect of improving the external quantum efficiency. It may be 2 μm or more, or 0.3 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, 0.2 to 1 It may be 0.0 μm, 0.2 to 0.6 μm, 0.2 to 0.4 μm, 0.3 to 1.0 μm, 0.3 to 0.6 μm, or 0.3 to 0.4 μm. From the viewpoint that such an average particle diameter (volume average diameter) can be easily obtained, the average particle diameter (volume average diameter) of the light-scattering particles used may be 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, and may be 1% by mass or more, based on the mass of the non-volatile content of the ink composition, from the viewpoint of being more excellent in the effect of improving the external quantum efficiency. 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 improving external quantum efficiency. % Or less, 40% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass. It may be less than or equal to%. 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 improving the external quantum efficiency. It may be 0.2 or more, or 0.5 or more. The mass ratio (light-scattering particles / luminescent nanocrystal particles) may be 5.0 or less from the viewpoint of excellent effect of improving external quantum efficiency and excellent continuous ejection property (ejection stability) during inkjet printing. , 2.0 or less, or 1.5 or less. The improvement of external quantum efficiency by 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, if 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 becomes possible to prevent leaked light (light that leaks from the pixel portion without being absorbed by the luminescent nanocrystal particles) by such a mechanism, and it is possible to improve the external quantum efficiency. It is thought that it can be done.

[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 bonded to the surface of the light-scattering particles and adsorbed to the light-scattering particles, but is bonded to the surface of the luminescent nanoparticles and adsorbed to the luminescent nanoparticles. It may be free in the ink composition.

By the way, one of the causes of deterioration in 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 improving the external quantum efficiency tends to decrease, and it is difficult to achieve both the ejection stability and the improvement of the external quantum efficiency at a high level. On the other hand, according to the ink composition further containing the polymer dispersant, excellent ejection stability and improvement of external quantum efficiency 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 phosphate group (-OPO (-OPO)). OH) ₃ ), phosphinic acid group (-PO (OH)-), mercapto group (-SH), and the like.

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

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

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 at a volume ratio of 1: 1 and 1 ml of a bromophenol blue test solution. Titrate with 5 mol / L ethanol 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. Examples of the polymer dispersant include acrylic resin, polyester resin, polyurethane resin, polyamide resin, polyether, phenol resin, silicone resin, polyurea resin, amino resin, epoxy resin, polyamine such as polyethyleneimine and polyallylamine, and polyimide. It may be there.

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

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, and may be 1000 or more, from the viewpoint of being able to satisfactorily disperse the light-scattering particles and further improving the effect of improving the external quantum efficiency. 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, further improve the effect of improving external quantum efficiency, and can eject the viscosity of the inkjet ink for stable ejection. From the viewpoint of obtaining a suitable viscosity, it may be 100,000 or less, 50,000 or less, or 30,000 or less.

From the viewpoint of the dispersibility of the light-scattering particles, the content of the polymer dispersant may be 0.5 parts by mass or more 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.

[solvent]
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-Butanediol diacetate, glyceryl triacetate and the like.

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.

In the ink composition of the present embodiment, since the photopolymerizable compound also functions as a dispersion medium, it is possible to disperse light-scattering particles and luminescent nanocrystal particles without a solvent. In this case, there is an advantage that the step of removing the solvent by drying when forming the pixel portion becomes unnecessary.

When the ink composition contains a solvent, the content of the solvent is 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass based on the total mass of the ink composition. It may be 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less.

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

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

When the viscosity of the ink composition at 40 ° C. is 2 mPa · s or more, or the viscosity of the ink composition at 23 ° C. is 5 mPa · s or more, the meniscus shape of the inkjet ink at the tip of the ink ejection hole of the ejection head. Is stable, so that the ejection control of the inkjet ink (for example, the control of the ejection amount and the ejection timing) becomes easy. On the other hand, when the viscosity of the ink composition at 40 ° C. is 20 mPa · s or less, or the viscosity of the ink composition at 40 ° C. is 40 mPa · s or less, the inkjet ink is smoothly ejected from the ink ejection holes. Can be done.

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 more, 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.

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 piezojet 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.

Although one embodiment of the ink composition for a color filter has 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.

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. Therefore, in this embodiment, an inkjet method that does not need to be treated with an alkaline developer (aqueous solution) is preferable.

Even when the coating film of the ink composition is not treated with the alkaline developer, if the ink composition is alkali-soluble, the coating film of the ink composition easily absorbs moisture in the atmosphere, and time elapses. As a result, 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 photopolymerizable compound as the photopolymerizable compound. The fact that the coating film of the ink composition is alkaline insoluble means that the amount of the coating film of the ink composition dissolved at 25 ° C. in a 1% by mass potassium hydroxide aqueous solution is based on the total mass of the coating film of the ink composition. It means that it is 30% by mass or less. The dissolved amount of the coating film of the ink composition is preferably 10% by mass or less, and more preferably 3% by mass or less. The fact that the ink composition is an ink composition capable of forming an alkali-insoluble coating film means that 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 method for producing an ink composition includes at least a step of mixing luminescent nanocrystal particles and an epoxy resin. For example, an ink composition can be obtained by mixing the constituent components of the above-mentioned ink composition and performing a dispersion treatment.

Hereinafter, as an example of a method for producing an ink composition, a method for producing an ink composition further containing light-scattering particles and a polymer dispersant will be described.

The method for producing the ink composition includes, for example, a first step of preparing a dispersion of light-scattering particles containing a light-scattering particle and a polymer dispersant, and a dispersion of light-scattering particles and a luminescent nano. It comprises a second step of mixing the crystal particles. In this method, the dispersion of the light-scattering particles may further contain the epoxy resin, and the epoxy resin 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 a dispersion of light-scattering particles, a dispersion of light-scattering particles is prepared by mixing the light-scattering particles, a polymer dispersant, and, in some cases, an epoxy resin, and performing a dispersion treatment. You can do it. The mixing and dispersion treatment may be performed using a dispersion device such as a bead mill, a paint conditioner, a planetary stirrer, or a jet mill. It is preferable to use a bead mill or a paint conditioner from the viewpoint that the dispersibility of the light-scattering particles is good and the average particle size of the light-scattering particles can be easily adjusted to a desired range. By mixing the light-scattering particles and the polymer dispersant before mixing the luminescent nanocrystal particles and the light-scattering particles, the light-scattering particles can be more sufficiently dispersed. Therefore, excellent ejection stability and excellent external quantum efficiency can be obtained more easily.

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

According to this method, the luminescent nanocrystal particles can be sufficiently dispersed. Therefore, 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 mixing and dispersion treatment of the luminescent nanocrystal particles and the epoxy resin are performed using the same dispersion device as in the step of preparing the dispersion of the light scattering particles. You may go.

In this production method, light-emitting nanocrystal particles, light-scattering particles, photopolymerizable compounds, photopolymerization initiators, organic ligands, and other components other than polymer dispersants (for example, sensitizers, solvents, etc.) are further added. You may use it. In this case, the other components may be contained in the luminescent nanocrystal particle dispersion or may be contained in the light scattering particle dispersion. Further, other components may be mixed with a composition obtained by mixing a luminescent nanocrystal particle dispersion and a light scattering particle dispersion.

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

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

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

<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 resin, specifically, a cured product obtained by polymerizing an epoxy resin. 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 the total mass of the cured product of the ink composition from the viewpoint of being superior in the effect of improving the external quantum efficiency and from the viewpoint of obtaining excellent emission intensity. It is preferably 5% by mass or more based on the above. From the same viewpoint, the content of the luminescent nanocrystal particles may be 10% by mass or more, 15% by mass or more, or 20% by mass based on the total mass of the cured product of the ink composition. It may be% or more. The content of the luminescent nanocrystal particles is preferably 50% 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 and excellent luminescence intensity. .. From the same viewpoint, the content of the luminescent nanocrystal particles may be 40% by mass or less, 35% by mass or less, or 30% by mass, based on the total mass of the cured product of the ink composition. It may be less than or equal to%.

The content of 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 being more excellent in the effect of improving the external quantum efficiency. 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. There may be. 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 improving the external quantum efficiency and excellent reliability of the pixel portion. , 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. , 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 the composition containing the above-mentioned photopolymerizable compound. The cured product contains a third cured component 13c. The third curing component 13c is a cured product of an epoxy resin, specifically, a cured product obtained by polymerizing an epoxy resin. 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 resin is the above-mentioned ink composition as long as the transmittance for light having a wavelength in the range of 420 to 480 nm is 30% or more. Of the components contained in the above, components other than the epoxy resin 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 containing light-shielding particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments in the binder polymer in addition to a metal such as chromium. Objects and the like can be used. The binder polymer used here includes one or a mixture of 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.

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

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

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

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

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

For example, the 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 and zinc oxide.

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

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

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

Further, in addition to the above-mentioned luminescent nanocrystal particles, the pixel portion of the light conversion layer of the present embodiment may further contain a pigment having substantially the same color as the luminescent color of the luminescent nanocrystal particles. 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, among the red pixel portion (R), the green pixel portion (G), and the blue pixel portion (B) in the optical conversion layer of the present embodiment, one or two types of pixel portions are luminescent nanocrystal particles. It may be a pixel portion containing a coloring material without containing the above. 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 an ε-type copper phthalosine pigment and / or a cationic blue organic dye. The amount of these coloring materials used is 1 to 5 mass based on the total mass of the pixel portion (cured product of the ink composition) from the viewpoint of preventing a decrease in transmittance when contained in the optical conversion layer. % Is preferable.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples. All the materials used in the examples were those in which argon gas was introduced and the dissolved oxygen was replaced with argon 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 red-emitting InP / ZnSeS / ZnS nanocrystal particle dispersion>
[Preparation of indium laurate solution]
10 g of 1-octadecene (ODE), 146 mg (0.5 mmol) of indium acetate and 300 mg (1.5 mmol) of lauric acid were added to the reaction flask to obtain a mixture. The mixture was heated at 140 ° C. for 2 hours under vacuum to obtain a transparent solution (indium laurate solution). This solution was kept in the glove box at room temperature until needed. Since indium laurate has low solubility at room temperature and easily precipitates, when using an indium laurate solution, the precipitated indium laurate in the solution (ODE mixture) is heated to about 90 ° C to become transparent. After forming the solution, the desired amount was weighed and used.

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

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

[Formation of shell (ZnSeS / ZnS shell) of red luminescent nanocrystal particles]
After adding 2.5 g of the hexane dispersion of the InP nanocrystal particles (InP core) obtained above to the reaction flask, 0.7 g of oleic acid was added to the reaction flask at room temperature, and the temperature was raised to 80 ° C. It was held for 2 hours. Then, 14 mg of diethylzinc, 8 mg of bis (trimethylsilyl) selenide and 7 mg of hexamethyldisirateyan (ZnSeS precursor solution) dissolved in 1 ml of ODE were added dropwise to this reaction mixture, and the temperature was raised to 200 ° C. and held for 10 minutes. This formed a ZnSeS shell with a thickness of 0.5 monolayer.

The temperature was then raised to 140 ° C. and held for 30 minutes. Next, a ZnS precursor solution obtained by dissolving 69 mg of diethylzinc and 66 mg of hexamethyldisiratean in 2 ml of ODE was added dropwise to this reaction mixture, and the temperature was raised to 200 ° C. and maintained for 30 minutes. A ZnS shell with a thickness of 2 monolayers was formed. After 10 minutes of dropping the ZnS precursor solution, the reaction was stopped by removing the heater. Next, the reaction mixture was cooled to room temperature, and the obtained white precipitate was removed by centrifugation, so that a transparent nanocrystal particle dispersion (InP / ZnSeS) in which red luminescent InP / ZnSeS / ZnS nanocrystal particles were dispersed was dispersed. / ODE dispersion of ZnS nanocrystal particles) was obtained.

[Synthesis of organic ligands for InP / ZnSeS / ZnS nanocrystal particles]
(Synthesis of organic ligand)
After putting JEFAMINE M-1000 (manufactured by Huntsman) into a flask, succinic anhydride (manufactured by Sigma-Aldrich) having an equimolar amount with JEFAMINE M-1000 was added thereto while stirring in a nitrogen gas environment. The internal temperature of the flask was raised to 80 ° C. and stirred for 8 hours to obtain a ligand represented by the following formula (A) as a pale yellow viscous oil.

[Preparation of red luminescent InP / ZnSeS / ZnS nanocrystal particle dispersion by ligand exchange]
(Preparation of InP / ZnSeS / ZnS nanocrystal particles modified with an organic ligand))
30 mg of the organic ligand was added to 1 ml of the ODE dispersion of the InP / ZnSeS / ZnS nanocrystal particles obtained above. Then, the ligand was exchanged by heating at 90 ° C. for 5 hours. 6 ml of ethanol was added to 1 ml of the nanocrystal particle solution after ligand exchange. Subsequently, centrifugation was performed to precipitate the nanocrystal particles, and then the supernatant was tilted and dried under vacuum to obtain nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles modified with the above organic ligand). The content of the organic ligand in the total amount of the nanocrystal particles modified with the organic ligand was 30% by mass. By dispersing the obtained nanocrystal particles in 1,4-BDDA (1,4-butanediol diacetate, manufactured by Daicel Co., Ltd.) so that the non-volatile content is 40.9% by mass, red light-emitting nanocrystals are used. A particle dispersion (1,4-BDDA dispersion) was obtained.

<Preparation of light-scattering particle dispersion>
Titanium oxide (trade name: CR-60-2, manufactured by Ishihara Sangyo Co., Ltd., average particle size (volume average diameter): 210 nm) was added to 33.0 g in a container filled with argon gas, and a polymer dispersant ( Trade name: Azispar PB-821 (manufactured by Ajinomoto Fine Techno Co., Ltd.) was mixed with 1.00 g and 1,4-BDDA 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. A light-scattering particle dispersion was obtained by removing the zirconia beads with a polyester mesh filter.

<Preparation of epoxy resin solution>
2.70 g of EPICLON N-865 (manufactured by DIC Co., Ltd., phenol / modified novolak type epoxy resin, epoxy equivalent: 209), which is an epoxy resin, and Ricacid HNA-100 (methylbicyclo [2.2.1], which is a curing agent. ] Heptane-2,3-dicarboxylic acid anhydride and bicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride mixed, manufactured by Shin Nihon Rika Co., Ltd.) at 2.30 g to accelerate curing. A total of 0.00500 g of DBMA (N, N-dimethylbenzylamine, manufactured by Tokyo Kasei Kogyo Co., Ltd.) as an agent is added to 1,4-BDDA (1,4-butane) so as to have a non-volatile content of 4.05% by mass. It was dissolved in diol diacetate, manufactured by Daicel Co., Ltd. (solvent) to obtain an epoxy resin solution.

<Preparation of red ink composition (inkjet ink)>
[Example 1]
0.480 g of a red light-emitting nanocrystal particle dispersion, 0.180 g of a light-scattering particle dispersion, and 0.341 g of an epoxy resin solution are uniformly mixed in a container filled with argon gas, and then in a glove box. Then, the mixture was filtered through a filter having a pore size of 5 μm. Further, it was introduced into a container containing a filtrate obtained by argon gas, and the inside of the container was saturated with argon gas. Then, the red ink composition (inkjet ink) of Example 1 was obtained by reducing the pressure and removing the argon gas.

[Example 2]
The red ink composition was the same as in Example 1 except that Hishikorin PX-4MP (methyltributylphosphonium dimethylphosphate, manufactured by Nippon Chemical Industrial Co., Ltd.) was used instead of N, N-dimethylbenzylamine as the curing accelerator. I got something.

[Comparative Example 1]
Examples except that Ricacid MH-700 (a mixture of 4-methylhexahydrophthalic anhydride and hexahydrophthalic anhydride, manufactured by NEW JAPAN CHEMICAL CO., LTD.) Was used as the curing agent instead of Ricacid HNA-100. A red ink composition was obtained in the same manner as in 1.

<Evaluation>
The viscosity of each ink composition immediately after preparation at 25 ° C. was measured with a TV-22 type viscometer (manufactured by Toki Sangyo Co., Ltd.). Subsequently, each ink composition was allowed to stand for 2 weeks in an environment in a vial whose inside was replaced with nitrogen. The viscosity of each ink composition after 2 weeks at 25 ° C. was measured by the same method as described above. The ratio of the viscosity of each ink composition after 2 weeks to the viscosity of each ink composition immediately after preparation was calculated as the viscosity increase rate. 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 ... first light-scattering particles, 12b ... second light-scattering particles, 20 ... light-shielding part, 30 ... light conversion layer, 40 ... base material, 100 ... color filter.

Claims (13)

It contains luminescent nanocrystal particles, an epoxy resin, and an acid anhydride-based curing agent.
An ink composition in which the acid anhydride-based curing agent has a bicyclo structure that shares at least three carbon atoms. The ink composition according to claim 1, further comprising light-scattering particles. The ink composition according to claim 1 or 2, further comprising a curing accelerator selected from a phosphonium salt. The ink composition according to any one of claims 1 to 3, which has a viscosity at 25 ° C. of 2 to 20 mPa · s. The ink composition according to any one of claims 1 to 4, further containing a solvent having a boiling point of 180 ° C. or higher. The ink composition according to any one of claims 1 to 5, wherein the content of the non-volatile component is 35% by mass or more based on the total mass of the ink composition. The ink composition according to any one of claims 1 to 6, wherein the surface tension is 20 to 40 mN / m. The ink composition according to any one of claims 1 to 7, which is for a color filter. The ink composition according to any one of claims 1 to 8, 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 9. 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,
10. The optical conversion layer according to claim 10. The light conversion layer according to claim 11, wherein the plurality of pixel portions 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. A color filter comprising the optical conversion layer according to any one of claims 10 to 12.

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