Display device including an inkjet composition and pixels formed therefrom

Abstract

To provide inkjet compositions that prevent the ink compositions discharged to adjacent pixels from being mixed together and allow a uniform coating layer to be formed.SOLUTION: An inkjet composition contains dispersed particles, a binder resin, a monomer, an initiator and a solvent. The content of the solvent is 0.1-20 wt.% relative to the total of the ink composition. The viscosity of the components excluding the solvent is 50-1000 cps.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an inkjet composition and a display device including pixels formed therefrom.

Background Art

[0002] Recently, a preferred means in consideration of process efficiency and economy is inkjet printing. Inkjet printing is a non-impact printing technology in which ink droplets are ejected onto a substrate through fine nozzles without contacting the nozzles with the substrate, and an ink composition is ejected into pixel openings of a partition wall to color a plurality of colors including red, green, and blue at once, having process simplification and excellent economic effects. The inkjet method using such an ink composition ejects a specific amount of ink into the pixel openings of the partition wall to satisfy a desired color coordinate or film thickness.

[0003] In this regard, Korean Registered Patent No. 10-1475520 (hereinafter, "Patent Document 1") discloses a technology related to an inkjet printing quantum dot ink composition containing quantum dots and a solvent, and containing the solvent in a content of 60 to 95% by weight.

[0004] When performing inkjet printing using an ink composition containing a solvent in a high content of 50% by weight or more as in Patent Document 1, considering that the solvent volatilizes in subsequent processes and the cured film thickness of the ink composition decreases, it is common to adjust and eject the amount of the ink composition so that the coating film thickness of the ink composition ejected onto the substrate can be formed to be about twice as high as the thickness of the partition wall.

[0005] However, the height of the partition wall can be formed relatively high as needed. In this case, the higher the height of the partition wall, the greater the ejection amount of the ink composition. When the ink composition exposed on the upper part of the partition wall becomes excessively large, there occurs a problem that the ejected ink composition is mixed with adjacent pixels. This can be generally referred to as an "Overflow" characteristic.

[0006] Therefore, there is a demand for the development of an inkjet composition that can solve the problem of mixing (the problem of being mixed) of each ink composition ejected onto adjacent pixels, regardless of the height of the partition wall.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] One object of the present invention is to provide an inkjet composition in which each ink composition ejected onto adjacent pixels is not mixed and a uniform coating film can be formed.

[0009] Another object of the present invention is to provide a display device including pixels manufactured using the inkjet composition.

Means for Solving the Problems

[0010] To solve the above problems, the present invention provides an inkjet composition including quantum dots, a binder resin, a monomer, an initiator, and a solvent, wherein the solvent is contained in an amount of 0.1 to 20% by weight based on the total ink composition, and the viscosity of the components excluding the solvent is 50 to 1000 cps.

[0011] The present invention also provides a display device including pixels manufactured using the inkjet composition.

Effects of the Invention

[0012] When the inkjet composition according to the present invention is used, it is possible to prevent the problem that the respective ink compositions ejected into the pixel openings of adjacent partition walls are mixed regardless of the height of the partition walls, and a uniform coating film can be formed.

Brief Description of Drawings

[0013]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0014] The present invention relates to an inkjet composition containing quantum dots, a binder resin, a monomer, an initiator, and a solvent, wherein the solvent is contained in an amount of 0.1 to 20% by weight based on the total ink composition, and the viscosity of the components excluding the solvent is 50 to 1000 cps, thereby preventing the problem that the respective ink compositions ejected into the pixel openings of adjacent partition walls are mixed and forming a uniform coating film, and a display device including a pixel formed therefrom.

[0015] In particular, the inkjet composition of the present invention is characterized in that the viscosity of the mixture of the components excluding the solvent falls within the above range, and the average molecular weight of the components excluding the scattering particles and the solvent in the composition is 3,000 g / mol or less, thereby having the effect of preventing problems such as nozzle clogging and generation of debris that solidifies and falls onto the substrate that may occur when the standing time is long during the inkjet process.

[0016] Hereinafter, the present invention will be described in detail. <Inkjet Composition> The inkjet composition of the present invention contains scattering particles, a binder resin, a monomer, an initiator, and a solvent, and may further contain one or more of quantum dots, epoxy compounds, and additives.

[0017] Scattered particles The inkjet composition according to the present invention contains scattering particles.

[0018] As the scattering particles, ordinary inorganic materials may be used, or preferably, metal oxides having an average particle diameter of 50 to 1000 nm may be included.

[0019] The metal oxide may be, but is not limited to, an oxide containing one kind of metal selected from the group consisting of Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Y, Mo, Cs, Ba, La, Hf, W, Tl, Pb, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Ti, Sb, Sn, Zr, Nb, Ce, Ta, In, and combinations thereof.

[0020] Specifically, one kind selected from the group consisting of Al2O3, SiO2, ZnO, ZrO2, BaTiO3, TiO2, Ta2O5, Ti3O5, ITO, IZO, ATO, ZnO-Al, Nb2O3, SnO, MgO, BaSO4, and combinations thereof can be used. If necessary, materials surface-treated with a compound having an unsaturated bond such as acrylate can also be used.

[0021] When the inkjet composition according to the present invention contains scattering particles, it is preferable because it can increase the path of light emitted from the light-emitting particles through the scattering particles and improve the overall light efficiency of the pixels formed with the inkjet composition.

[0022] The scattering particles may have an average particle size of 50 to 1000 nm, and preferably those in the range of 100 to 500 nm are used. At this time, if the particle size is too small, a sufficient scattering effect of the light emitted from the quantum dots cannot be expected. Conversely, if it is too large, the particles may sink in the composition or the surface of the self-luminescent layer with uniform quality cannot be obtained. Therefore, it is appropriately adjusted within the above range before use.

[0023] The scattering particles may be contained in an amount of 5 to 50% by weight, preferably 10 to 45% by weight, more preferably 20 to 40% by weight, based on 100% by weight of the entire inkjet composition. When the scattering particles are contained within the above range, the effect of increasing the emission intensity can be maximized, which is preferable. When the scattering particles are contained less than the above range, it may be somewhat difficult to ensure the desired emission intensity. When exceeding the above range, the transmittance of the blue irradiation light is significantly reduced, and the problem of decreased luminance may occur. Therefore, it is preferably used appropriately within the above range.

[0024] Binder resin The inkjet composition of the present invention contains a binder resin. The binder resin may contain an oxetane compound.

[0025] When a cationic photoinitiator is present, the oxetane compound can be polymerized or crosslinked by irradiation with light.

[0026] The oxetane compound is not particularly limited as long as it has at least one oxetanyl group in the molecule, and various oxetane compounds well known in the art can be used. Further, the oxetane compound may be used alone or in admixture of two or more.

[0027] Examples of the oxetane compound of the present invention include 3-ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane, 1,4-bis[(3-ethyloxetan-3-yl)methoxymethyl]benzene, 1,4-bis[(3-ethyloxetan-3-yl)methoxy]benzene, 1,3-bis[(3-ethyloxetan-3-yl)methoxy]benzene, 1,2-bis[(3-ethyloxetan-3-yl)methoxy]benzene, 4,4'-bis[(3-ethyloxetan-3-yl)methoxy]biphenyl, 2,2'-bis[(3-ethyloxetan-3-yl)methoxy]biphenyl, 3,3',5,5'-tetramethyl-4,4'-bis[(3-ethyloxetan-3-yl)methoxy]biphenyl, 2,7-bis[(3-ethyloxetan-3-yl)methoxy]naphthalene, bis[4-{(3-ethyloxetan-3-yl)methoxy}phenyl]methane, bis[2-{(3-ethyloxetan-3-yl)methoxy}phenyl]methane, 2,2-bis[4-{(3-ethyloxetan-3-yl)methoxy}phenyl]propane, an etherified product of novolac-type phenol-formaldehyde resin with 3-chloromethyl-3-ethyloxetane, 3(4),8(9)-bis[(3-ethyloxetan-3-yl)methoxymethyl]-tricyclo[5.2.1.0 2,6 decane, 2,3-bis[(3-ethyloxetan-3-yl)methoxymethyl]norbornane, 1,1,1-tris[(3-ethyloxetan-3-yl)methoxymethyl]propane, 1-butoxy-2,2-bis[(3-ethyloxetan-3-yl)methoxymethyl]butane, 1,2-bis[{2-(3-ethyloxetan-3-yl)methoxy}ethylthio]ethane, bis[{4-(3-ethyloxetan-3-yl)methylthio}phenyl]sulfide, bis[{1-ethyl(3-oxetanyl)}methyl]ether, and 1,6-bis[(3-ethyloxetan-3-yl)methoxy]-2,2,3,3,4,4,5,5-octafluorohexane, etc.

[0028] When the binder resin contains an oxetane compound, the oxetane compound can be used alone or in combination with one or more compounds selected from the group consisting of epoxy compounds and vinyl ether compounds.

[0029] The binder resin may be contained in an amount of 5 to 30% by weight, preferably 10 to 20% by weight, based on 100% by weight of the entire inkjet composition. When the binder resin is contained within the above range, an increase in the viscosity of the composition can be suppressed, so that the processability is improved, which is preferable.

[0030] Monomer In one embodiment of the present invention, the inkjet composition contains a monomer.

[0031] The monomer may contain one or more compounds selected from the compounds represented by the following Chemical Formula 1 and Chemical Formula 2.

[0032] [Chemical Formula 1] TIFF0007717312000001.tif19115

[0033] In Chemical Formula 1, R1 and R2 are each independently a substituted or unsubstituted alkoxylene group having 1 to 5 carbon atoms, R3 and R4 are each independently hydrogen or a methyl group, and n and m are each independently an integer of 1 to 3.

[0034] [Chemical Formula 2] TIFF0007717312000002.tif17114

[0035] In Chemical Formula 2, R5 and R6 are each independently hydrogen or a methyl group, R7 is a substituted or unsubstituted alkoxylene group having 1 to 5 carbon atoms, and l is an integer of 1 to 3.

[0036] As used herein, the C1-C5 alkoxylene group means a linear or branched divalent alkoxy group composed of 1 to 5 carbon atoms, and includes, for example, divalent methoxy, ethoxy, etc., but is not limited thereto.

[0037] One or more hydrogens of the C1-C5 alkoxylene group can be substituted with a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, a C3-C 10 cycloalkyl group, a C3-C 10 heterocycloalkyl group, a C3-C 10 heterocycloalkyloxy group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 thioalkoxy group, an aryl group, an acyl group, hydroxy, thio, halogen, amino, alkoxycarbonyl, carboxy, carbamoyl, cyano, nitro, etc. Preferably, it can be substituted with a hydroxy group.

[0038] As described above, in one embodiment of the present invention, R1, R2, and / or R7 may be a C1-C5 alkoxylene group, and preferably, may be a divalent alkoxylene group having 2 or 3 carbon atoms. At this time, one or more hydrogens of the alkoxylene group can be substituted with a hydroxy group. When R1, R2, and / or R7 is a C2-C3 alkoxylene group, the inkjet composition of the present invention can improve the inkjet jetting characteristics.

[0039] Specific examples of the compound represented by Chemical Formula 1 include, but are not limited to, the following Chemical Formulas 1-1 to 1-4, etc.

[0040] [Chemical Formula 1-1] TIFF0007717312000003.tif18134

[0041] [Chemical Formula 1-2] TIFF0007717312000004.tif19134

[0042] [Chemical Formula 1-3] TIFF0007717312000005.tif19134

[0043] [Chemical Formula 1-4] TIFF0007717312000006.tif18134

[0044] In addition, specific examples of the compound represented by the Chemical Formula 2 include, but are not limited to, the following Chemical Formulas 2-1 to 2-2, etc.

[0045] [Chemical Formula 2-1] TIFF0007717312000007.tif21114

[0046] [Chemical Formula 2-2] TIFF0007717312000008.tif18114

[0047] The monomer contained in the inkjet composition of the present invention can adjust the viscosity of the composition when the amount of the solvent is limited to a small amount and / or when there is no solvent by including the compound represented by the Chemical Formula 1 and / or Chemical Formula 2. Further, it can show uniformity in coating by including the monomer having the specific chemical formula structure.

[0048] The inkjet composition of the present invention may further contain monomers commonly used in the art within the scope not departing from the object of the present invention, in addition to the monomers represented by the Chemical Formula 1 and / or Chemical Formula 2. For example, monofunctional monomers, bifunctional monomers, and other polyfunctional monomers can be mentioned, among which bifunctional monomers are preferably used.

[0049] The type of the monofunctional monomer is not particularly limited, and examples thereof include nonylphenyl carbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-ethylhexyl carbitol acrylate, 2-hydroxyethyl acrylate, N-vinylpyrrolidone, and the like.

[0050] The type of the bifunctional monomer is not particularly limited, and examples thereof include bis(acryloyloxyethyl) ether of bisphenol A.

[0051] The type of the polyfunctional monomer is not particularly limited, and examples thereof include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, propoxylated dipentaerythritol hexa(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0052] The monomer may be contained in an amount of 10 to 70% by weight, preferably 20 to 60% by weight, based on 100% by weight of the entire inkjet composition. When the monomer is contained within the above range, there are preferable advantages in terms of the strength and smoothness of the pixel portion. When the polymerizable monomer is contained in an amount less than the above range, it becomes difficult to ensure the fluidity for inkjetting, and when it is contained in an amount exceeding the above range, it may cause a problem that the content of the light-emitting particles is insufficient and the light efficiency is reduced. Therefore, it is preferably contained within the above range.

[0053] Initiator The inkjet composition according to an embodiment of the present invention may contain a photoinitiator.

[0054] In one embodiment of the present invention, the photoinitiator can be used without particular limitation as long as it can polymerize the monomer. For example, from the viewpoints of polymerization characteristics, initiation efficiency, absorption wavelength, availability, price, etc., the photoinitiator is preferably one or more compounds selected from the group consisting of acetophenone-based compounds, benzophenone-based compounds, triazine-based compounds, non-imidazole-based compounds, oxime-based compounds, and thioxanthone-based compounds.

[0055] The photoinitiator may be contained in an amount of 1 to 15% by weight, preferably 2 to 10% by weight, based on 100% by weight of the entire inkjet composition. When the photoinitiator is contained within this range, photocuring occurs effectively, which is preferable.

[0056] The photoinitiator may further contain a photoinitiator co - agent in order to improve the sensitivity of the inkjet composition according to the present invention. When the photoinitiator co - agent is contained, there are advantages that the sensitivity becomes even higher and the productivity is improved.

[0057] The photoinitiator co - agent is preferably one or more compounds selected from the group consisting of, for example, amine compounds, carboxylic acid compounds, and organic sulfur compounds having a thiol group, but is not limited thereto.

[0058] The photoinitiator co - agent can be appropriately added and used within a range that does not impair the effects of the present invention.

[0059] Quantum dot The inkjet composition of the present invention may further contain quantum dots. The quantum dots may be those that emit spontaneous light by a light source and are used to generate light in the visible light and infrared regions. The quantum dots may be substances having a crystal structure of several nanosizes and may be composed of about several hundreds to several thousands of atoms. Atoms form molecules, and the molecules form aggregates of small molecules called clusters to form nanoparticles. Usually, when such nanoparticles exhibit semiconductor properties, they are called quantum dots. The quantum dots of the present invention are not particularly limited as long as they conform to such a concept. When an object becomes smaller than the nanosize, a quantum confinement effect, which is a phenomenon in which the energy band gap of the object increases, occurs. When the quantum dots receive energy from the outside and reach an excited state, they can spontaneously emit light by emitting energy corresponding to the energy band gap.

[0060] The quantum dots are not particularly limited as long as they are particles of quantum dots that can emit light by stimulation with light or electricity. For example, they may be selected from the group consisting of II-VI group semiconductor compounds; III-V group semiconductor compounds; IV-VI group semiconductor compounds; group IV elements or compounds containing the same; and combinations thereof, and these may be used alone or in combination of two or more.

[0061] For example, the II-VI group semiconductor compound may be selected from the group consisting of binary compounds such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, and mixtures thereof; ternary compounds selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, and mixtures thereof; and quaternary compounds selected from the group consisting of CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and mixtures thereof, but is not limited thereto.

[0062] The III-V group semiconductor compound may be selected from the group consisting of binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, and mixtures thereof; and quaternary compounds selected from the group consisting of GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof, but is not limited thereto.

[0063] The IV-VI group semiconductor compound may be one or more selected from the group consisting of binary compounds selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; ternary compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; and quaternary compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof, but is not limited thereto.

[0064] Although not limited thereto, the Group IV element or a compound containing the same may be selected from the group consisting of elements selected from the group consisting of Si, Ge, and mixtures thereof; and binary compounds selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0065] The quantum dots may have a homogeneous single structure; a double structure such as a core-shell structure and a gradient structure; or a mixed structure thereof, and in the present invention, the type of the quantum dots is not particularly limited as long as they can emit light by light stimulation.

[0066] According to one embodiment, the quantum dots have a core-shell structure, the core includes one or more selected from the group consisting of InP, InZnP, InGaP, CdSe, CdS, CdTe, ZnS, ZnSe, ZnTe, CdSeTe, CdZnS, CdSeS, PbSe, PbS, PbTe, AgInZnS, HgS, HgSe, HgTe, GaN, GaP, GaAs, InGaN, InAs, and ZnO, and the shell may include one or more selected from the group consisting of ZnS, ZnSe, ZnTe, ZnO, CdS, CdSe, CdTe, CdO, InP, InS, GaP, GaN, GaO, InZnP, InGaP, InGaN, InZnSCdSe, PbS, TiO, SrSe, and HgSe. Preferably, it may include one or more selected from the group consisting of InP / ZnS, InP / ZnSe, InP / GaP / ZnS, InP / ZnSe / ZnS, InP / ZnSeTe / ZnS, and InP / MnSe / ZnS.

[0067] Generally, quantum dots can be manufactured by a wet chemical process, a metal organic chemical vapor deposition (MOCVD) process, or a molecular beam epitaxy (MBE) process.

[0068] The wet chemical process is a method of growing particles by putting precursor substances in an organic solvent. When crystals grow, the organic solvent is naturally coordinated to the surface of the quantum dot crystals, serving as a dispersant to regulate crystal growth. Therefore, the growth of the size of quantum dot particles can be controlled through a process that is easier and cheaper than vapor deposition methods such as metal organic chemical vapor deposition and molecular beam epitaxy.

[0069] In the present invention, the quantum dots may be contained in an amount of 5 to 50% by weight, preferably 15 to 40% by weight, and more preferably 20 to 35% by weight, based on 100% by weight of the entire inkjet composition. When the light-emitting particles are contained within the above range, the light conversion efficiency can be improved. When the quantum dots are contained within the above range, there are advantages of excellent light efficiency and excellent reliability of the coating layer. When the quantum dots are contained in an amount less than the above range, the light conversion efficiency of green light and red light becomes slight, and even when the amount exceeds the above range, there is a problem that the converted luminance decreases. This is considered to be because the light converted by the contained quantum dots is blocked by the excessive quantum dots, or the excessive quantum dots convert blue light first, and there is no blue light for the excessive quantum dots to convert, resulting in an unnecessary role.

[0070] Epoxy compound The inkjet composition of the present invention may further contain an epoxy compound.

[0071] The epoxy compound is not particularly limited as long as it is an epoxy compound containing one or more functional groups capable of polymerizing cations in the presence of the above-mentioned photoinitiator. The epoxy compound may be a monomer, an aromatic epoxy compound, a cycloaliphatic epoxy compound, a heterocyclic or aliphatic epoxy compound, or may be used alone or in combination of two or more.

[0072] The aromatic epoxy compound means an epoxy compound containing an aromatic group in the molecule, and for example, bisphenol A-based epoxy, bisphenol F-based epoxy, bisphenol S-based epoxy, and bisphenol bromide-based epoxy such as bisphenol type epoxy resins; novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; cresol epoxy and resorcinol glycidyl ether may be used.

[0073] The alicyclic epoxy compound means a compound in which an epoxy group is formed between two adjacent carbon atoms constituting an aliphatic ring. For example, dicyclopentadiene dioxide, limonene dioxide, 4-vinylcyclohexene dioxide, 2,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl) adipate, etc. may be used.

[0074] As the aliphatic epoxy compound, polyglycidyl ethers of aliphatic polyhydric alcohols; polyglycidyl ethers of alkylene oxide adducts of aliphatic polyhydric alcohols, etc. may be used.

[0075] The aliphatic polyhydric alcohol may be, for example, an aliphatic polyhydric alcohol having 2 to 20 carbon atoms. More specifically, aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol; alicyclic diols such as cyclohexanedimethanol, cyclohexanediol, hydrogenated bisphenol A, and hydrogenated bisphenol F; polyols having a valence of 3 or more such as trimethylolethane, trimethylolpropane, hexitols, pentitols, glycerin, polyglycerin, pentaerythritol, dipentaerythritol, polycaprolactone, and tetramethylpropane.

[0076] Further, the epoxy compound may preferably be at least one selected from the group consisting of aromatic epoxy compounds and cycloaliphatic epoxy compounds.

[0077] The epoxy compound may be contained in an amount of 5 to 30% by weight, preferably 10 to 25% by weight, more preferably 10 to 20% by weight, based on 100% by weight of the entire inkjet composition. When the epoxy compound is contained within the above range, there is an effect of improving the strength of the coating film, which is preferable. When the epoxy compound is contained in less than the above range, the strength is low and there may be a problem that the coating film is damaged, so it is preferably used appropriately within the above range.

[0078] Additive The inkjet composition according to an embodiment of the present invention may further contain additives such as a surfactant and an adhesion promoter in addition to the above-described components in order to enhance the coating film flatness or adhesion.

[0079] When the inkjet composition according to the present invention contains the surfactant, there is an advantage that the coating film flatness can be improved. For example, as the surfactant, fluorine-based surfactants such as BM-1000, BM-1100 (BM Chemie), Prolide FC-135 / FC-170C / FC-430 (Sumitomo 3M Limited), SH-28PA / -190 / -8400 / SZ-6032 (Toray Silicone Co., Ltd.), and F552 (DIC Corporation) can be used, but are not limited thereto.

[0080] The adhesion promoter can be added to enhance the adhesion to the substrate, and may include a silane coupling agent having a reactive substituent selected from the group consisting of a carboxyl group, a methacryloyl group, an isocyanate group, an epoxy group, and combinations thereof, but is not limited thereto.

[0081] In addition, the inkjet composition according to the present invention may further contain additives such as an antioxidant, an ultraviolet absorber, and an anti-aggregation agent, as long as the effects of the present invention are not inhibited. Also, those skilled in the art can appropriately add and use the additives as long as the effects of the present invention are not inhibited.

[0082] The additives can be used in an amount of 0.01 to 5% by weight, specifically 0.02 to 3% by weight, and more specifically 0.03 to 0.1% by weight, based on 100% by weight of the entire inkjet composition, but are not limited thereto.

[0083] Solvent The inkjet composition according to an embodiment of the present invention contains a solvent and may contain it, for example, in an amount of 0.1 to 20% by weight based on 100% by weight of the entire inkjet composition.

[0084] As the solvent, an ether or ester solvent, an aliphatic saturated hydrocarbon solvent, a halogenated hydrocarbon solvent, an aromatic hydrocarbon solvent, etc. can be used. For example, propylene glycol methyl ether acetate (PGMEA), ethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoalkyl ethers such as ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dialkyl ethers such as diethylene glycol dibutyl ether, ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate, alkylene glycol alkyl ether acetates such as propylene glycol monopropyl ether acetate, methoxybutyl acetate, and methoxypentyl acetate, aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene, ketones such as methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone, alcohols such as ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, and glycerin, esters such as ethyl 3-ethoxypropionate and methyl 3-methoxypropionate, cyclic esters such as γ-butyrolactone, etc. can be used.

[0085] <Display device> One embodiment of the present invention relates to a display device including pixels manufactured using the above-described inkjet composition.

[0086] According to the present invention, the inkjet composition can be applied to various image display devices such as a normal liquid crystal display device (LCD), an electroluminescent display device (EL), a plasma display device (PDP), a field emission display device (FED), and an organic light emitting element (OLED).

[0087] The display device of the present invention includes a configuration known in the art, except that it includes pixels manufactured using the aforementioned inkjet composition.

Examples

[0088] Hereinafter, experimental examples including specific examples and comparative examples will be presented for the understanding of the present invention. However, these are merely illustrative of the present invention and do not limit the scope of the appended claims. It is obvious to those skilled in the art that various changes and modifications can be made to the examples within the scope of the present invention and its technical concept. It is natural that such variations and modifications belong to the scope of the appended claims. Note that, unless otherwise specified, “%” and “parts” indicating content hereinafter are based on weight.

[0089] <Synthesis Example> Synthesis Example 1: Synthesis of alkali-soluble resin A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen inlet tube was prepared. On the other hand, 15 parts by weight of N-benzylmaleimide, 30 parts by weight of acrylic acid, 50 parts by weight of cyclohexyl methacrylate, 5 parts by weight of methyl methacrylate, 4 parts by weight of t-butylperoxy-2-ethylhexanoate, and 40 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as PGMEA) were added, and then stirred and mixed to prepare a monomer dropping funnel. 6 parts by weight of n-dodecanediol and 24 parts by weight of PGMEA were added and stirred and mixed to prepare a chain transfer agent dropping funnel.

[0090] Thereafter, 395 parts by weight of PGMEA was introduced into the flask, the atmosphere in the flask was replaced from air to nitrogen, and then the temperature of the flask was raised to 90 °C while stirring. Subsequently, the dropping of the monomer and the chain transfer agent was started from the dropping funnel. The dropping was carried out for 2 hours each while maintaining 90 °C. After raising the temperature to 110 °C and holding for 3 hours after 1 hour, a gas inlet tube was introduced, and bubbling of an oxygen / nitrogen = 5 / 95 (v / v) mixed gas was started.

[0091] Subsequently, 20 parts by weight of glycidyl methacrylate, 0.4 parts by weight of 2,2'-methylenebis(4-methyl-6-t-butylphenol), and 0.8 parts by weight of triethylamine were charged into a flask, and the reaction was continued at 110°C for 6 hours. Then, it was cooled to room temperature to obtain an alkali-soluble resin having a weight average molecular weight of 4,800 and an acid value of 83 mgKOH / g based on solid content.

[0092] Production Example 1: Photosensitive resin composition for forming partition walls Each component was mixed with the composition shown in Table 1 below to produce a photosensitive resin composition for forming a partition (unit: wt%).

[0093]

Table 1

[0094] - Colorant: White 6 (Pigment White 6), C.I. Pigment White 6 (R-102, manufactured by Dupont) - Binder: The alkali-soluble resin of Synthesis Example 1 - Monomer: Dipentaerythritol hexaacrylate (KAYARAD DPHA, manufactured by Nippon Chemical Co., Ltd.) - Initiator: IRGACURE OXE-03 (manufactured by BASF) - Additive: Silane coupling agent (KBM-9007, manufactured by Shin-Etsu) - Liquid repellent: Reactive liquid repellent (RS-90, manufactured by DIC) - Solvent: Propylene glycol monomethyl ether acetate (PGMEA) Examples and Comparative Examples Each component was mixed with the composition shown in Table 2 below, and a solvent was added thereto in the content shown in Table 3 to produce an inkjet composition. In Table 2 below, the average molecular weight is the average molecular weight of the remaining components excluding the scattering particles.

[0095]

Table 2

[0096] (A) TiO2 (TR-81 from Huntsman, TiO2 content 93%, treated with Alumina and zirconia) (B) InP / ZnSe / ZnS quantum dots (fluorescence λem = 532 nm, FWHM = 37 nm, Green QD, nanosheath) (C) InP / ZnSe / ZnS quantum dots (fluorescence λem = 630 nm, FWHM = 39 nm, Red QD, nanosheath) Monomer: (M1) 1,6 - hexanediol diacrylate of Chemical Formula 2 - 2 (HDDA, Sigma - Aldrich) (M2) 2,2 - Bis[4-(2 - hydroxy - 3 - methacryloyloxypropoxy)phenyl]propane of Chemical Formula 1 - 1 (Bis - GMA, Polysciences) (M3) Triethylene glycol dimethacrylate of Chemical Formula 2 - 1 (TEGDMA, Sigma - Aldrich) (M4) Bisphenol - A ethoxylate(1EO / phenol)diacrylate of Chemical Formula 1 - 4 (1EO - DA, Sigma - Aldrich) Epoxy: Alicyclic epoxy compound (Celloxide 2021P from Daicel) Binder: Oxetane group - containing compound (OXT - 221 from TOAGOSEI) Initiator: Photoinitiator (OXE - 03 from BASF) Additive (leveling agent): Fluorine - based surfactant (F552 from DIC)

[0097]

Table 3

[0098] Experimental Example 1. Evaluation of Inkjet A partition wall with a thickness of 10 μm was formed on a substrate using the photosensitive resin composition for partition wall formation manufactured through Production Example 1.

[0099] Thereafter, each inkjet composition produced in the Examples and Comparative Examples was applied by an inkjet method onto the substrate on which the partition walls were formed.

[0100] Inks without solvents were used based on the active ingredients excluding solvents, and it was evaluated that the number of drops for filling the pixels was 24 drops. Therefore, when jetting Comparative Example 5 (Production Example 2 - 50%, solvent 50%), since the coating films for filling the pixels must be the same after removing all the solvents, when jetting 48 drops, the active ingredients can fill the pixels after removing all the solvents.

[0101] The image with Over characteristics is as shown in Fig. 1 (Comparative Example 4, Production Example 2 - 33%). In the image of Fig. 2, a phenomenon occurred where the third pixel and the fourth pixel were combined due to the Over characteristics. When combined in this way, the respective ink compositions are mixed, resulting in the formation of non-uniform pixels. The Over characteristics were evaluated and entered in Table 4.

[0102] For the evaluation of uniformity, jetting was performed so that the coating film thickness would be the same based on the active ingredients on the substrate as shown in Fig. 2. Referring to Fig. 2(A), for the result value of Comparative Example 1, without solvents, 24 drops were jetted and exposed at a wavelength of 365 nm with 2000 mJ / cm 2 After exposure, the film thickness was measured using an Alpha Step (Dektak XT - A) device. Fig. 2(B) shows the result value with the Y-axis enlarged, and it can be confirmed that the height of the coating film formed in the pixel portion has a value between 12 and 12.5 μm. The evaluation of uniformity was performed by calculating the result value with such a height difference. The result value was entered in Table 4.

[0103] 1) Evaluation of Over characteristics In order to form a coating film remaining after removing the solvent, different numbers of jetting operations were performed according to the solvent content, and at that time, it was determined whether adjacent pixels and the inkjet composition were combined.

[0104] <Evaluation Criteria for Over Characteristics> ◎: None of the 100 pixels have Over characteristics ○: Among the 100 pixels, Over occurs in 1 pixel △: Among the 100 pixels, Over occurs in 2 - 3 pixels X: Among the 100 pixels, Over occurs in 4 or more pixels 2) Evaluation of Uniformity The film thickness of the coating film formed by jetting the same number of droplets to each effective component reference pixel excluding the solvent was measured, and the uniformity was evaluated based on the deviation.

[0105] <Evaluation Criteria for Uniformity> ◎: The difference between the maximum and minimum values of the vertex heights of 5 pixels is 0.1 μm or less ○: The difference between the maximum and minimum values of the vertex heights of 5 pixels exceeds 0.1 μm and is 0.2 μm or less △: The difference between the maximum and minimum values of the vertex heights of 5 pixels exceeds 0.2 μm and is 0.4 μm or less X: The difference between the maximum and minimum values of the vertex heights of 5 pixels exceeds 0.4 μm, or there is no evaluation value due to pixel combination in the evaluation of Over characteristics.

[0106] 3) Evaluation of Shelf Life Characteristics The inkjet equipment continuously jets droplets during jetting. However, when the jetting position of the substrate is moved or the substrate is changed, jetting must be stopped and it enters the standby state. In this case, solvent volatilization occurs, and only the active ingredient remains at the position of the outermost shell of the nozzle. It was confirmed whether the active ingredient has the property of being redissolved by the subsequent inkjet composition of the inkjet equipment.

[0107] <Evaluation Criteria for Shelf Life Characteristics> After dropping 1 ml of the inkjet composition onto a glass substrate, the solvent is dried at a temperature of 50°C. Thereafter, the same inkjet composition is dropped onto the dried inkjet composition to confirm its redissolvability.

[0108] ◎: Redissolvability OK X: Redissolvability NG

[0109]

Table 4

[0110] Referring to Table 4, when the inkjet composition according to the embodiment of the present invention is used, it is possible to reduce the deviation due to the discharge amount of the composition in the inkjet process, form a uniform coating film, and it can be seen that there is no problem of mixing of the compositions discharged into the pixel openings of adjacent partition walls. In addition, all of the compositions of the examples show excellent results in terms of standing properties, and from this, it can be seen that it is possible to prevent problems such as nozzle clogging and generation of chips that solidify and fall onto the substrate that may occur when the standing time becomes long during the inkjet process.

[0111] On the other hand, when the inkjet composition according to the comparative example is used, as shown in FIG. 1, it can be seen that there is a problem of mixing of the ink compositions discharged into the pixel openings of adjacent partition walls in the inkjet process, resulting in the formation of non-uniform pixels or a significant decrease in standing properties.

Claims

1. A composition for inkjet printing, comprising scattered particles, an oxetane compound, a monomer, an initiator, and a solvent, wherein the scattered particles include one or more selected from the group consisting of Al₂O₃, SiO₂, ZnO, ZrO₂, BaTiO₃, TiO₂, Ta₂O₅, Ti₃O₅, ITO, IZO, ATO, ZnO - Al, Nb₂O₃, SnO, MgO, and combinations thereof, wherein the solvent is contained in an amount of 0.1 to 20% by weight based on the total ink composition, and the viscosity of the components excluding the solvent is 50 to 1000 cps.

2. The composition for inkjet printing according to claim 1, wherein the monomer includes one or more compounds selected from the compounds represented by the following Chemical Formula 1 and Chemical Formula 2: [Chemical Formula 1] In Chemical Formula 1, R １ and R ２ are each independently a substituted or unsubstituted C1-C5 alkoxylene group, R ３ and R ４ are each independently hydrogen or a methyl group, n and m are each independently an integer from 1 to 3. [Chemical Formula 2] In Chemical Formula 2, R ５ and R ６ are each independently hydrogen or a methyl group, R ７ is a substituted or unsubstituted alkoxylene group having 1 to 5 carbon atoms, l is an integer from 1 to 3.

3. The composition for inkjet printing according to claim 2, wherein the monomer includes one or more of the compounds represented by the following Chemical Formulas 1 - 1 to 1 - 4 and Chemical Formulas 2 - 1 to 2 - 2. [Chemical Formula 1 - 1] [Chemical Formula 1 - 2] [Chemical Formula 1 - 3] [Chemical Formula 1 - 4] [Chemical Formula 2 - 1] [Chemical Formula 2 - 2]

4. The composition for inkjet printing according to claim 1, further comprising one or more selected from quantum dots, epoxy compounds, and additives, wherein the additives include one or more selected from the group consisting of surfactants, adhesion promoters, antioxidants, ultraviolet absorbers, anti - agglomeration agents, and combinations thereof.

5. A display device comprising pixels manufactured using the composition for inkjet printing according to any one of claims 1 to 4.

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