KR102102560B1 - Quantum Dot Film and Wavelength Converting sheet for Display comprising Quantum Dot complex - Google Patents

Abstract

The present invention relates to a quantum dot complex improving quantum dot efficiency by uniformly dispersing quantum dots in a matrix resin, and capable of preventing the deterioration of the quantum dots through encapsulation, to a quantum dot film comprising the same, and to a wavelength conversion sheet for a display.

Description

Quantum Dot Film and Wavelength Converting sheet for Display comprising Quantum Dot complex

The present invention relates to a quantum dot film comprising a quantum dot composite, and a wavelength conversion sheet for display.

Quantum Dot (QD) refers to ultra-fine semiconductor particles having a size of several nanometers. When exposed to light, the quantum dots emit light of a specific frequency while electrons in an unstable state descend from the conduction band to the valence band.

In general, quantum dots generate shorter wavelengths of light as the particles are smaller, and emit longer wavelengths of light as the particles are larger. Accordingly, when the size of the quantum dots is adjusted, visible light having a desired wavelength may be expressed, and various colors may be simultaneously implemented using quantum dots of various sizes. Therefore, it is possible to realize a desired natural color by controlling the size of the quantum dots, and it has attracted attention as a next-generation light source because of its good color reproduction and good luminance.

After forming the quantum dots into films, barrier films are mounted on both sides to produce a wavelength conversion sheet, which is applied to the light guide plate of a liquid crystal display (LCD) backlight unit. When the blue light irradiated from the backlight unit passes through the quantum dot sheet, the red quantum dot is converted to red, the green quantum dot is converted to green to emit light, and the blue light is emitted as it is, and full color can be realized. The display using the QD has the advantage of being able to combine blue and green with red light close to natural light, so that it can express colors close to natural light in a wide range that conventional phosphors did not.

Conventional quantum dot film is prepared by mixing a quantum dot with a curable resin, and then forming a coating film. Since the quantum dots have a size of several nanometers, it is difficult to achieve uniform dispersion in the curable resin due to agglomeration between each other, so that the uniformity of light emission is greatly reduced. In particular, there is a problem in that the light conversion efficiency rapidly decreases due to contact with moisture or air (that is, oxygen) penetrating from the outside of the quantum dot, and the display life is reduced.

In addition, the wavelength conversion sheet is manufactured in a multi-layered structure, and when the adhesion between the quantum dot film and the barrier film is low, moisture and air are more easily penetrated, and the quantum dot film is peeled from the barrier film and quantum dots are oxidized.

This problem can be overcome by encapsulating a quantum dot with a hydrophobic resin, and the hydrophobic resin exhibits a low adhesion to the barrier film, which creates another problem.

Recently, for uniform dispersion of the quantum dots and adhesion to the barrier film, a method has been proposed in which quantum dots are granulated in an encapsulated form, and the encapsulated quantum dots are dispersed in a matrix resin with a resin having a high adhesion to the barrier film. However, the quantum dot film thus produced has a problem of agglomeration with each other when encapsulation of the quantum dots, resulting in a problem that the particle size distribution is very wide, resulting in low luminous efficiency.

To this end, in Korean Patent Registration No. 10-1396871, the surface of the quantum dots is encapsulated with polyethylene-based wax, polypropylene-based wax or amide-based wax to disperse stability , There have been attempts to increase ultraviolet stability and heat / moisture stability. The wax is a polar wax having an acid value in the range of 1 mg KOH / g to 200 mg KOH / g, and it is difficult to achieve uniform dispersion when mixed with hydrophobic quantum dots.

In addition to the above patents, a method of encapsulating using wax has been proposed in many patents. As an example, the use of wax is mentioned in US 9,534,313, US 2002-0096795 and US 2006-0286378. However, these patents merely mention the contents of known waxes, and do not suggest any specific examples or dispersion or effects of quantum dots using them. Moreover, neither of these patents has any mention of the wavelength conversion sheet.

Meanwhile, a commercially available quantum dot dispersion is dispersed in a solvent such as toluene, and a dispersion is prepared by replacing the solvent with a low-viscosity acrylic monomer such as isobornyl acrylate.

This quantum dot dispersion can be used as it is in the process without removal of the isobornyl acrylate in the preparation of quantum dot films, such as isobornyl acrylate can reach the polymerization through a double bond in the molecular structure, there is an advantage of low toxicity . However, during the manufacturing process of the film, the quantum dots and isobornyl acrylate content are applied in the same ratio, so that the optical properties of the film are changed according to the content control or it is difficult to secure the properties and reliability of the designed bar. For this reason, isobornyl acrylate is used as a solvent before the film production process, but in this case, the stability of the quantum dots is lowered, resulting in a problem that the optical properties of the manufactured quantum dot films are lowered.

Republic of Korea Patent Publication No. 10-2016-0069393, (2016.06.16), a method of manufacturing a light conversion composite material, light conversion composite material, a light conversion sheet comprising the same, a backlight unit and a display device Republic of Korea Patent Publication No. 10-2013-0027317 (2013.03.15), a quantum dot composite and its manufacturing method Republic of Korea Patent Publication No. 10-2017-0092934 (2017.08.14), a composition for an optical film and an optical film comprising the same Republic of Korea Patent Registration No. 10-1396871 (May 19, 2014), composites, compositions and devices comprising the same US 9,534,313 (2017-01-03), Particles including nanoparticles dispersed in solid wax, method and uses thereof US 2002-0096795 (2003-03-04), Encapsulation of discrete quanta of fluorescent particles US 2006-0286378 (2006-12-21), Nanostructured composite particles and corresponding processes

Accordingly, the present inventors have continuously conducted research in consideration of the above-mentioned problems in various ways. In particular, the quantum dots are encapsulated with a non-polar polyolefin-based wax or an ultraviolet curable silicone-based compound. And, by dispersing it in a photocurable matrix resin, it has advantages in various aspects such as dispersibility of quantum dots, uniformity of particles, convenience in process, adhesion to barrier films, and improved physical properties of the obtained quantum dot films and wavelength conversion sheets. Was confirmed.

Accordingly, an object of the present invention is to provide a quantum dot film and a method for manufacturing the same.

In addition, an object of the present invention is to provide a wavelength conversion sheet comprising the quantum dot film.

In order to achieve the above object, the present invention provides a quantum dot composite in which quantum dots are dispersed in an acrylic monomer or a polymer thereof and encapsulated with an encapsulating resin.

The acrylic monomer has an uncured liquid phase, and its polymer is characterized in that the acrylic monomer is photocured.

In addition, the present invention provides a quantum dot film in which the quantum dot composite is dispersed in a matrix resin and a wavelength conversion sheet comprising the same.

Method of manufacturing a quantum dot composite according to an embodiment of the present invention

a1) preparing a dispersion in which a surfactant is dispersed in a first solvent,

b1) adding a non-polar polyolefin-based wax, a quantum dot, an acrylic monomer, a photoinitiator and a second solvent having a repeating structure of Formula 1 and Formula 2 to the dispersion,

c1) encapsulating quantum dots by solidifying the non-polar polyolefin-based wax by heating and cooling the obtained composition; And

d1) recovering the encapsulated quantum dot complex after filtration.

[Formula 1]

_{- [CH 2 -CH 2] a} -

[Formula 2]

-[CH ₂ -CHR ₁ ] _b-

(In the formulas 1 and 2, R ₁ is a C1 to C15 linear or branched alkyl group, 0.01≤b≤0.96, and satisfies a + b = 1.)

In addition, the method of manufacturing a quantum dot composite according to another embodiment of the present invention

a2) mixing a liquid UV-curable silicone-based resin, quantum dots, acrylic monomer, and photoinitiator,

b2) preparing a dispersion in which the surfactant is dispersed in the first solvent,

c2) adding a liquid UV-curable silicone resin, quantum dots, acrylic monomer, photoinitiator and second solvent mixed in the dispersion,

d2) encapsulating the obtained composition with ultraviolet light to encapsulate a quantum dot, an acrylic monomer, and a photoinitiator with a silicone resin, and

e2) recovering the encapsulated quantum dot complex after filtration.

In addition, the manufacturing method of the quantum dot composite according to another embodiment of the present invention

a3) mixing a liquid thermosetting silicone-based resin, a quantum dot, an acrylic monomer, and a photoinitiator,

b3) preparing a dispersion in which the surfactant is dispersed in the first solvent,

c3) adding a liquid thermosetting silicone resin, a quantum dot, an acrylic monomer, a photoinitiator and a second solvent to the dispersion,

d3) encapsulating the silicone resin by applying heat to the obtained composition to encapsulate the quantum dot, acrylic monomer, and photoinitiator, and

e3) recovering the encapsulated quantum dot complex after filtration.

The quantum dot composite according to the present invention is encapsulated using a non-polar polyolefin-based wax or an ultraviolet curing silicone-based compound, and the quantum dots are dispersed as the quantum dots are dispersed as they are used together with an acrylic monomer capable of photocuring before or after encapsulation. The quantum dot film can be stably produced without aggregation.

The quantum dot film thus manufactured can uniformly disperse quantum dots in the matrix resin at high concentrations to increase the conversion efficiency of the quantum dots, and prevents moisture or oxygen penetration from outside due to the encapsulating resin encapsulating the quantum dots and the resin constituting the matrix resin. , It not only has excellent optical transmittance but also prevents deterioration of quantum dots.

The quantum dot film can be applied to a wavelength conversion sheet for a display, and a high quality screen can be realized.

The quantum dots are dispersed in a matrix resin for the production of a quantum dot film, which is either dispersed in the matrix as it is or dispersed in an encapsulated form. For the encapsulation, a method using an encapsulating resin is used. At this time, there is a problem in that the content of the quantum dots in the encapsulated quantum dots is non-uniform, and there is a disadvantage that oxygen or moisture in the air cannot be sufficiently blocked.

Accordingly, in the present invention, when encapsulating a quantum dot, a method of increasing the stability of the quantum dot and the reliability of the produced quantum dot film by uniformly dispersing the quantum dots by using a separate acrylic polymer in addition to the encapsulating resin and effectively blocking oxygen or moisture in the air present.

The encapsulating resin referred to in this specification is a hydrophobic (Hydrophobic) property or a resin having properties that improve one or more of the functions such as hardness, oxygen permeation reduction, water molecule permeation reduction, and the like. The encapsulating resin means a resin that is cured by being mixed with an acrylic monomer or polymer in which quantum dots are dispersed, or cured while including an acrylic monomer or polymer in which quantum dots are dispersed. That is, in the present specification, the meaning of 'encapsulated by an encapsulating resin' is that the quantum dot is cured by being mixed with a dispersed acrylic monomer or polymer, and is not in the form of a coating layer as the simple term "capsule" means.

Hereinafter, the present invention will be described in detail.

Quantum dot complex

The quantum dot according to the present invention is a quantum dot composite encapsulated with an encapsulating resin, wherein the quantum dots inside the encapsulating resin have a form dispersed in an acrylic monomer or a polymer thereof.

The quantum dot emits light by absorbing light injected from a light source through a quantum confinement effect, and then converting a wavelength of light having a wavelength corresponding to a band gap of the quantum dot.

The quantum dot may include a semiconductor selected from the group consisting of II-VI, III-V, IV-VI, and IV semiconductors and mixtures thereof. More specifically, the quantum dots are, for example, CdS, CdO, CdSe, CdTe, Cd ₃ P ₂ , Cd ₃ As ₂ , ZnS, ZnO, ZnSe, ZnTe, MnS, MnO, MnSe, MnTe, MgO, MgS, MgSe, MgTe, CaO, CaS, CaSe, CaTe, SrO, SrS, SrSe, SrTe, BaO, BaS, BaSe, BaTE, HgO, HgS, HgSe, HgTe, HgI ₂ , AgI, AgBr, Al ₂ O ₃ , Al ₂ S ₃ , Al ₂ Se ₃ , Al ₂ Te ₃ , Ga ₂ O ₃ , Ga ₂ S ₃ , Ga ₂ Se ₃ , Ga ₂ Te ₃ , In ₂ O ₃ , In ₂ S ₃ , In ₂ Se ₃ , In ₂ Te ₃ , SiO ₂ , GeO ₂ , SnO ₂ , SnS, SnSe, SnTe, PbO, PbO ₂ , PbS, PbSe, PbTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, GaInP ₂ , InN, Single layer or multi-layer structure comprising one or more semiconductor crystals selected from the group consisting of InP, InAs, InSb, In ₂ S ₃ , In ₂ Se ₃ , TiO ₂ , BP, Si, Ge, and combinations thereof It may be a particle of.

In addition, the quantum dot is CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe group II-VI compound semiconductor nanocrystals, GaN, GaP, GaAs, InP, InAs group III-V compound semiconductor Nanocrystals or mixtures thereof. The central particle may have a core / shell structure, and each of the core and the shell of the central particle may include the compounds exemplified above. The above-described compounds may be included alone or in combination of two or more, respectively, in the core or shell. For example, the central particle may have a CdSe / ZnS (core / shell) structure having a core including CdSe and a shell including ZnS.

Further, the particles of the quantum dot may have a core / shell structure or an alloy structure. A quantum dot having a core / shell structure can grow a shell layer in various shapes by adding other components in growing the crystal structure of the seed. In the case of forming the core / shell structure, while satisfying characteristics such as high luminous efficiency and high luminous clarity, other characteristics such as thermal stability or insulation can be satisfied simultaneously. The quantum dot particles having such a core / shell structure or an alloy structure are CdSe / ZnS, CdSe / ZnSe / ZnS, CdSe / CdSx (Zn1-yCdy) S / ZnS, CdSe / CdS / ZnCdS / ZnS, InP / ZnS, InP / Ga / ZnS, InP / ZnSe / ZnS, PbSe / PbS, CdSe / CdS, CdSe / CdS / ZnS, CdTe / CdS, CdTe / ZnS, CuInS ₂ / ZnS, Cu ₂ SnS ₃ / ZnS.

Further, the quantum dots may be perovskite nanocrystalline particles. The perovskite comprises a structure of ABX ₃ , A ₂ BX ₄ , ABX ₄ or A _n-1 B _n X _{3n + 1} (n is an integer between 2 and 6), wherein A is an organoammonium or alkali metal material , Wherein B is a metallic material, and X may be a halogen element.

The organic ammonium is an amidium-based organic ion, (CH ₃ NH ₃ ) _n , ((C _x H _{2x + 1} ) _n NH ₃ ) ₂ (CH ₃ NH ₃ ) _n , (RNH ₃ ) ₂ , (C _n H _{2n + 1} NH ₃ ) ₂ , (CF ₃ NH ₃ ), (CF ₃ NH ₃ ) _n , ((C _x F _{2x + 1} ) _n NH ₃ ) ₂ (CF ₃ NH ₃ ) _n , ((C _x F _{2x + 1} ) _n NH ₃ ) ₂ or (C _n F _{2n + 1} NH ₃ ) ₂ ) (n is an integer of 1 or more, x is an integer of 1 or more), and the alkali metal material is Na, K, Rb, Cs or Fr. B is a divalent transition metal, rare earth metal, alkaline earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, or a combination thereof, and X is Cl, Br, I ion Or a combination thereof.

Further, the quantum dots may be doped perovskite nanocrystalline particles. The doped perovskite includes a structure of ABX ₃ , A ₂ BX ₄ , ABX ₄ or A _n-1 B _n X _{3n + 1} (n is an integer between 2 and 6), and part of the A is A ', Or part of the B is substituted with B', or part of the X is replaced with X ', wherein A and A' are organic ammonium, and B and B 'are metal materials , X and X 'may be a halogen element.

At this time, A and A 'are amidium-based organic ions, (CH ₃ NH ₃ ) _n , ((C _x H _{2x + 1} ) _n NH ₃ ) ₂ (CH ₃ NH ₃ ) _n , (RNH ₃ ) ₂ , (C _n H _{2n + 1} NH ₃ ) ₂ , (CF ₃ NH ₃ ), (CF ₃ NH ₃ ) _n , ((C _x F _{2x + 1} ) _n NH ₃ ) ₂ (CF ₃ NH ₃ ) _n , ( (C _x F _{2x + 1} ) _n NH ₃ ) ₂ or (C _n F _{2n + 1} NH ₃ ) ₂ and (n is an integer of 1 or more, x is an integer of 1 or more), and B and B 'are divalent transition metals , Rare earth metal, alkaline earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi or Po, and X and X 'may be Cl, Br or I.

The quantum dots may be spherical, elliptical, rod-shaped, wire, pyramid, cube or other geometric or non-geometric shape. It is usually spherical or elliptical nanoparticles, has an average particle diameter of 1 to 20 nm, preferably 1 to 10 nm, and the emission wavelength varies depending on the size, so that light of a desired color can be obtained by selecting a quantum dot of an appropriate size. . Quantum dots, which are usually larger in particle size, emit light of lower energy when compared to quantum dots that are made from the same material but have a smaller particle size. In the present invention, the quantum dots, for example, may include at least one selected from the group consisting of quantum dots for converting blue light to red light, quantum dots for converting blue light to green light, and quantum dots for converting green light to red light.

Particularly, the quantum dots are supplied in a colloidal (or dispersion) state dispersed in a solvent (eg, toluene), and supplied in a form in which a ligand is attached for surface stabilization. At this time, the ligand is a hydrophobic organic ligand, which increases the dispersibility of the quantum dots and prevents them from sticking together. The ligand may be removed before use or substituted with another ligand. The ligands can prevent quantum dots adjacent to each other easily aggregate and quench with each other. In addition, the ligand binds to the quantum dot, so that the quantum dot is hydrophobic. Accordingly, when the quantum dots and the quantum dots containing the ligand are dispersed in a coating layer or a resin for forming a film, dispersibility for the resin may be improved compared to a quantum dot without a ligand.

The ligand may be represented by the formula-(CH ₂ ) _p -R ₃ (1≤p≤40, R ₃ = OH, CO ₂ H, NH ₂ , SH, or PO). Preferably, 6≤p≤30, and the alkyl group represented by CH ₂ may be linear or branched.

As a specific example, the ligands include hexadecylamine, octadecyl amine, octylamine, trioctylphosphine, triphenolphosphine, and t-butylphosphine. t-butylphosphine), trioctylphosphine oxide, pyridine or thiophene, preferably octadecylamine.

As the additive, a surface treatment agent such as a phosphoric acid ester compound having an acid value of 10 or more may be used.

The phosphoric acid ester-based compound may include a form in which the hydrogen atom of the hydroxy group or the hydroxy group present in the phosphoric acid ester ((HO) ₂ PO (OR)) or phosphoric acid (H ₃ PO ₄ ) is substituted or unsubstituted with another functional group. For example, the phosphate ester compounds (H ₂ PO ₃ ^-), but may be represented in the form of, but is not limited to such. In addition, in the present invention, the "phosphoric acid ester system" may include at least one selected from the group consisting of phosphorous acid derivatives, phosphoric acid derivatives, phosphonic acid derivatives, and phosphinic acid derivatives.

When the surface treatment agent contains the phosphoric acid ester-based compound, there is an advantage that can suppress the reduction in quantum efficiency. The phosphoric acid ester-based compound may further include at least one of a polyether moiety, a polyester moiety and a phosphoric acid group in one molecule.

The surface treatment agent may be included in 1 to 250 parts by weight based on 100 parts by weight of the total quantum dot solid content, preferably 3 to 200 parts by weight, more preferably 5 to 100 parts by weight.

When the surface treatment agent is included within the above range, the deagglomeration effect of the quantum dots is excellent, and the precipitation phenomenon due to polarity difference between the quantum dot dispersion liquid and the other composition according to the present invention can be suppressed, and serves as a protective layer of the quantum dots in the film manufacturing process It is preferable because it can be performed.

If the surface treatment agent is included below the above range, the deagglomeration effect of the quantum dots may be slightly lowered, and if it is included above the above range, the developing properties of the resin composition containing the quantum dot dispersion may be slightly lowered, so within the above range It is preferably included.

Further, in the quantum dot composite of the present invention, the quantum dots are dispersed in an acrylic monomer or a polymer thereof. The acrylic monomer has an uncured liquid phase, and is polymerized into an acrylic polymer through photocuring.

After the photo-curing, the acrylic polymer effectively blocks oxygen or moisture in the air to further increase the stability of the quantum dots and the reliability of the produced quantum dot films.

The acrylic monomer is used in the liquid phase at room temperature for uniform dispersion of quantum dots in the manufacturing process, for example, has a viscosity of 3 to 500 cps. The acrylic monomer has a functional group that can be polymerized or cured by light irradiation in a molecular structure.

The acrylic monomers that can be used are as follows, wherein the term '(meth) acrylate' refers to methacrylate or acrylate.

The acrylic monomer may be a monofunctional acrylic monomer having one functional group in a molecular structure, or two or more polyfunctional acrylic monomers / oligomers.

The monofunctional acrylic monomer is isobornyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, norbornyl (meth) Acrylate, isodecyl (meth) acrylate, cyclohexyl (meth) acrylate, n-hexyl (meth) acrylate, adamantyl acrylate, acryloylmorpholine, tetrahydrofuryl (meth) acrylate, 2- It may include one or more monomers selected from the group consisting of phenoxyethyl (meth) acrylate, caprolactone (meth) acrylate and cyclopentyl acrylate.

In addition, as the polyfunctional acrylic monomer, tripropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate , Cyclic trimethylolpropane (meth) acrylate, trimethylcyclohexyl (meth) acrylate, tricyclodicaine dimethanol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylol Propane tri (meth) acrylate (3EO-TMPTA; ethoxylated trimethylolpropane tri (metha) acrylate), ethoxylated pentaerythritol tri (meth) acrylate (4EO-PETA; ethoxylated pentaerythritol triacrylate), pentaerythritol tri ( Meth) acrylate, and dipentaerythritol hexa (meth) acrylate. have.

And, as the polyfunctional acrylic oligomer, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, acrylic (meth) acrylate, polybutadiene (meth) acrylate, silicone (meth) acrylic And one or more oligomers selected from the group consisting of rate and melamine (meth) acrylate. At this time, the oligomer may have a weight average molecular weight in the range of 100 to 1000.

Among them, a non-polar acrylate is selected from the group consisting of isobornyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, and 3,3,5-trimethylcyclohexyl (meth) acrylate. More than one species is used, and most preferably, isobornyl acrylate (IBOA), isodecyl acrylate (IDA), and isobornyl methacrylate (IBOMA) are used.

When two or more functional groups are included in the acrylic monomer, they may be crosslinked by light irradiation, and if necessary, a known photocrosslinking agent may be further used.

In the quantum dot composite according to the present invention, an acrylic monomer or a polymer thereof is used in an amount of 10 to 500 parts by weight, 20 to 300 parts by weight, and 50 to 200 parts by weight based on 100 parts by weight of the quantum dots. If the content is less than the above range, the blocking effect of oxygen or moisture in the air due to the acrylic monomer or polymer thereof is insufficient. Conversely, if it is outside the above range, the size of the quantum dot composite increases more than necessary or the transparency of the film when applied to the quantum dot film And lower the quantum efficiency of the quantum dots, so use appropriately within the above range.

On the other hand, the quantum dot composite of the present invention has a structure encapsulated by using an encapsulating resin for quantum dots dispersed in an acrylic monomer or a polymer thereof.

The encapsulating resin is cured by mixing with an acrylic monomer or polymer in which quantum dots are dispersed, or curing while including an acrylic monomer or polymer in which quantum dots are dispersed. For this reason, the encapsulated structure 'is not in the form of a "simple coating or a coating layer such as a coating film" which means "capsule", but means that the quantum dots are cured in a mixed state with dispersed acrylic monomers or polymers. .

The encapsulating resin is a hydrophobic (Hydrophobic) property or a resin having properties that improve one or more of functions such as hardness, oxygen permeation reduction, water molecule permeation reduction, and the like, and preferably a non-polar olefin wax or silicone resin.

As one example of the encapsulating resin, it may be a non-polar polyolefin-based wax, which is a compound capable of solidifying by heat.

The wax-based compound is a resin having a molecular weight in the hundreds to tens of thousands of times at a solid state, but having a melting point at 40 to 180 ° C and increasing the temperature above the melting point to turn into a fluid. The resins include petroleum wax, animal natural wax, vegetable natural wax, and synthetic wax depending on the raw material. Among them, in the present invention, a polyolefin-based wax, preferably a non-polar (or non-polar) polyolefin-based wax.

Molecules show polarity and non-polarity depending on the atomic arrangement, and polarities are mixed between polarities and non-polarities. Usually, the bonding force of polarity is higher than that of non-polar bonding, so that the non-polar molecules cannot break the bond between polar molecules, so that mixing between them is not achieved.

In the pre-encapsulation state described above, the acrylic polymer exists as an uncured, ie, liquid phase monomer.

The non-polar polyolefin-based wax of the present invention exists as a lamellar model in which the folded state forms a bundle after the polymer chain is unfolded, rather than the chains being disorderly and messyly arranged. The quantum dots and uncured acrylic monomers are safely settled between the chains constituting the lamella. As a result, the solidification of the encapsulating resin is achieved due to a decrease in temperature, and inclusion of quantum dots and uncured acrylic monomers between the chains.

At this time, the ligand on the surface of the quantum dot has hydrophobicity, and at the same time, non-polar, and the acrylic monomer in the uncured state also has hydrophobicity. Accordingly, when a polar polymer is used to enclose quantum dots and uncured acrylic monomers, the quantum dots or uncured acrylic monomers exist outside the lamellar structure of the encapsulating resin, so that their inclusion is not smooth. The binding of the non-polar molecules is made by the van der Waals action. In the present invention, when a polymer having a non-polarity is used, the van der Waals action occurs for the ligand of the quantum dot and the acrylic monomer in an uncured state. As a result, quantum dots and uncured acrylic monomers exist between or near polymer chains in a entangled state, so that a large amount of quantum dots can be more uniformly enclosed after the final curing.

A typical wax among polyolefin waxes is polyethylene wax. The polyethylene wax has a repeating unit of-[CH ₂ -CH ₂ ]-, and exhibits non-polarity because it has a symmetrical structure of CH ₂ . The ligand of the quantum dot is present between the CH ₂ chains of the polyethylene-based wax. At this time, when a hydrophobic substituent exists instead of H linked to C, the substituent acts as an arm, so that the quantum dot and the uncured acrylic monomer are added to the polymer. It can be fixed more easily. Usually, the increase in hydrophobicity may vary depending on the type and length of the substituent.

In the present invention, by substituting a part of H of CH ₂ with an alkyl group, while maintaining non-polarity and increasing hydrophobicity, the chance of van der Waals action on the ligand of the quantum dot and the acrylic monomer in the uncured state is increased. Specifically, the non-polar polyolefin-based wax substituted with an alkyl group includes a repeating structure of Formula 1 and Formula 2 below.

[Formula 1]

_{- [CH 2 -CH 2] a} -

[Formula 2]

-[CH ₂ -CHR ₁ ] _b-

(In the formulas 1 and 2, R ₁ is a C1 to C15 linear or branched alkyl group, 0.01≤b≤0.96, and satisfies a + b = 1.)

Preferably, R ₁ is a C1 to C15 alkyl group, more preferably a C1 to C10 alkyl group. At this time, the alkyl group is a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dode It may be a silyl group, isopropyl group, t-butyl group, isobutyl group, 2-methyl-pentyl group, 2-ethyl-hexyl group, 2-propyl-heptyl group, 2-butyl-octyl group. The hydrophobicity increases as the number of carbon atoms in the R ₁ increases, and acrylic monomers in a quantum dot and an uncured state can be more easily encased. However, if it is too long, it may be advantageous to have a substituent within the range of the carbon number, since it may prevent penetration of quantum dots and uncured acrylic monomers.

In this case, when R ₁ is an alkyl group, the alkyl group may be one or more alkyl groups. That is, when the repeating unit of Formula 2 together with Formula ₁ forms a main chain, R ₁ may be substituted only with a methyl group (eg, HDPE), or two or more kinds such as a methyl group, a propyl group, and / or a hexyl group.

In addition, b is related to the degree of substitution of the alkyl group, and the higher the value, the higher the degree of substitution of the alkyl group. When the degree of substitution of the alkyl group is high, hydrophobicity increases, but physical properties as 'wax' of excessive substitution, that is, the melting point is increased, making it difficult to prepare an emulsion composition. Therefore, it is important to limit the values of a and b.

Specifically, b is 0.01 to 0.50, more preferably 0.03 to 0.30, and a value of a has a range satisfying a + b = 1.

In addition, the non-polar polyolefin-based wax of the present invention has a molecular weight of 300 to 30,000, preferably 700 to 25,000, more preferably 1000 to 20,000, and a melting point of 40 to 180 ° C, preferably 90 to 170 ° C, more preferably 100 To 160 ° C.

According to a specific example of the present invention, the non-polar polyolefin wax may be high density polyethylene (HDPE), low density polyethylene (LDPE), or linear low density polyethylene (LLDPE) wax. At this time, the HDLE, LDPE, and LLDPE are due to the density difference according to the manufacturing method, HDPE is 0.941 g / cm ³ or more, LDPE is 0.915-0.925 g / cm ³ , LLDPE is 0.915-0.925 g / cm ³ Have

Previously, a technique using a polyethylene-based wax for encapsulation of quantum dots has been proposed, but since this polyethylene is essentially non-polar, when it is mixed with other materials of polarity, that is, quantum dots, encapsulation of quantum dots due to weak interaction at the interface Is not easy. For this reason, a method of modifying the polyethylene wax with a substituent having a polar group is used, but the cost in the process has increased. Since the quantum dot usually exhibits hydrophobicity, the use of a polyethylene-based wax substituted with a polar group has a problem that it is not easy to enclose a sufficient amount of quantum dots. However, by using a non-polar polyolefin-based wax having the repeating structures of Formulas 1 and 2, the above-described problem can be fundamentally blocked. Moreover, it is advantageous because it is possible to lower the process cost and simplify the process in that the ligand treatment of commercially available quantum dots is not required.

As another example of the encapsulating resin, the encapsulating resin may be a silicone-based resin.

The silicone-based resin is a liquid siloxane polymer, and may be a linear silicone oil and a modified silicone oil depending on the type of organic bond to the silicon atom and the degree of polymerization of the siloxane. Typical linear silicone oils are dimethyl silicone oils in which all organic groups are methyl groups, methylphenyl silicone oils incorporating phenyl groups, methylphenyl silicone oils, diphenylsilicone oils, copolymers of polysiloxanes and diphenylsiloxanes, methylhydrogen silicone oils, etc. There is this. The modified silicone oil means a silicone oil incorporating an organic group other than a methyl group or a phenyl group, methyl hydroxy silicone oil, fluoro silicone oil, polyoxyether copolymer, alkyl-modified silicone oil, higher fatty acid-modified silicone oil, amino roadside And silicone oils and epoxy-modified silicone oils. These silicone-based liquid resins having a viscosity of 50 cps? Ps at room temperature have low surface tension. In addition, since it is non-polar, it is soluble in aromatic solvents such as toluene and xylene, and is poorly soluble in polar solvents of water or alcohol.

Encapsulation using a silicone-based resin can be achieved through curing, and the curing depends on a curing reaction mechanism and may be a thermosetting silicone-based resin or an ultraviolet curing silicone-based resin.

The curing may be thermal curing or ultraviolet curing, and a curing agent such as an organic peroxide may be used for thermal curing, and an ultraviolet curing agent may be used for ultraviolet curing. If necessary, a platinum catalyst can be used to promote curing.

In the case of thermal curing, the use of a curing agent compared to a silicone resin may vary depending on the curing mechanism. In one example, addition reaction occurs in the presence of a platinum catalyst, or curing is possible through free radical reaction by applying organic peroxide and heat. At this time, examples of the organic peroxide include 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, dicumyl peroxide, di-tert-butylperbenzoate and 2,5-bis (tert-butylperoxy) benzoate. have. The organic peroxide is used in a concentration of 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight relative to 100 parts by weight of the silicone resin.

In the quantum dot composite according to the present invention, the encapsulating resin is used in an amount of 10 to 600 parts by weight, 50 to 400 parts by weight, and 100 to 300 parts by weight based on 100 parts by weight of the quantum dots. If the content is less than the above range, uniform dispersion of the quantum dots is difficult, and the blocking effect of oxygen or moisture in the air is insufficient. Conversely, if the content is outside the above range, the size of the quantum dot composite increases more than necessary or the film transparency when applied to the quantum dot film In addition to lowering, since the quantum efficiency of the quantum dots may be reduced, it is appropriately used in the above range.

In addition, the quantum dot composite of the present invention may have a size ranging from 0.1 μm to 200 μm, 0.5 μm to 180 μm, 1 μm to 150 μm, and 5 μm to 100 μm. This size can be controlled by the content of quantum dots, acrylic monomers or polymers and encapsulating resins, and when it has the above range, various physical properties including quantum efficiency of quantum dots are excellent.

Quantum dot film

The quantum dot composite of the present invention as described above is dispersed in a matrix resin, which can be manufactured in various forms, but is preferably produced in a quantum dot film state in a film state.

Since the resin constituting the matrix resin maintains optical transparency and must be used in a form attached to another film (eg, a barrier film) due to the properties of the quantum dot film, it must have high adhesion to other films and can satisfy these properties. Resins of a good nature can be used.

The matrix resin of the present invention can be a photocurable resin in which polymerization occurs by active energy rays, and a resin having a hydrophilicity is possible unlike the encapsulating resin so as to be suitable for a manufacturing method using an emulsion.

'Photocurable resin' is a component that crosslinks as radicals are generated in the molecular chain with strong active energy rays such as UV, EB, and radiation. After the photoinitiator contained in the pressure-sensitive adhesive absorbs ultraviolet rays having a wavelength of 200 to 400 nm to show reactivity, it reacts with a monomer, which is a main component of the resin, and is cured by polymerization. When the photoinitiator contained in the photocurable resin receives UV, a photopolymerization reaction is initiated, and the oligomer and monomer, which are the main components of the resin, are polymerized and cured.

Preferably, the matrix resin is an acrylic polymer. The acrylic polymer may be prepared through polymerization of at least one composition consisting of an acrylic oligomer, an acrylic monomer, and a combination thereof, and the matrix resin obtained after final curing may be an acrylic resin.

The acrylic oligomer may be an epoxy acrylate resin.

The epoxy acrylate resin is a resin in which the epoxide group of the epoxy resin is substituted with an acrylic group, for example, the epoxy acrylate resin is bisphenol-A glycerolate diacrylate, bisphenol-A. Bisphenol A ethoxylate diacrylate, bisphenol A glycerolate dimethacrylate, bisphenol A ethoxylate dimethacrylate, and combinations thereof It can be any one selected from the county. Epoxy acrylate resin, like the epoxy resin, has low moisture permeability and moisture permeability due to its main chain properties.

The acrylic monomer that can be used is not particularly limited in the present invention, and any of those known can be used. Representatively, the acrylic monomer may be one or more homopolymers or copolymers selected from the group consisting of an unsaturated group-containing acrylic monomer, an amino group-containing acrylic monomer, an epoxy group-containing acrylic monomer, and a carboxylic acid group-containing acrylic monomer.

As the unsaturated group-containing acrylic monomer, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, i-propyl acrylate, i-propyl methacrylate , n-butyl acrylate, n-butyl methacrylate, i-butyl acrylate, i-butyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, t-butyl acrylate, t-butyl meth Acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl Methacrylate, 2-hydroxybutylacrylate, 2-hydroxybutylmethacrylate, 3-hydroxybutylacrylate, 3-hydroxybutylmethacrylate, 4-hydroxybutylacrylate, 4- Doxybutyl methacrylate, allyl acrylate, allyl methacrylate, benzyl acrylate, benzyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, phenyl acrylate, phenyl methacrylate, 2-methoxyethyl Acrylate, 2-methoxyethyl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, methoxydiethylene glycol acrylate, methoxydiethylene glycol methacrylate, methoxytriethylene glycol acrylic Rate, methoxytriethylene glycol methacrylate, methoxypropylene glycol acrylate, methoxypropylene glycol methacrylate, methoxydipropylene glycol acrylate, methoxydipropylene glycol methacrylate, isobornyl acrylate, isobornyl Methacrylate, dicyclopentadiethylacrylate, dicyclopentadiene A methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxy-3-phenoxypropyl methacrylate, glycerol monoacrylate, glycerol monomethacrylate, etc. is possible.

As an amino group-containing acrylic monomer, 2-aminoethyl acrylate, 2-aminoethyl methacrylate, 2-dimethylaminoethyl acrylate, 2-dimethylaminoethyl methacrylate, 2-aminopropyl acrylate, 2-aminopropyl methacrylate Acrylate, 2-dimethylaminopropylacrylate, 2-dimethylaminopropylmethacrylate, 3-aminopropylacrylate, 3-aminopropylmethacrylate, 3-dimethylaminopropylacrylate, 3-dimethylaminopropylmethacrylate Rates, etc. are possible.

Epoxy group-containing acrylic monomers include glycidyl acrylate, glycidyl methacrylate, glycidyloxyethyl acrylate, glycidyloxyethyl methacrylate, glycidyloxypropyl acrylate, glycidyloxypropyl methacrylate Acrylate, glycidyloxybutyl acrylate, glycidyloxybutyl methacrylate, and the like.

Acrylic monomers containing carboxylic acid groups include acrylic acid, methacrylic acid, acryloyloxyacetic acid, methacryloyloxyacetic acid, acryloyloxypropionic acid, methacryloyloxypropionic acid, acryloyloxybutyric acid, and methacryloyloxybutyric acid Etc. are possible.

The quantum dot composite with respect to 100 parts by weight of the matrix resin containing the photo-curable resin is 0.5 to 30 parts by weight, preferably 1 to 15 parts by weight. If the content of the quantum dot composite is less than the above range, the light conversion effect is insignificant and the light conversion efficiency is lowered.

If necessary, the matrix resin may further include a crosslinking agent for crosslinking. Specific examples of the crosslinking agent used in the present invention include ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups, trimethylolpropane di (meth) acrylate, and trimethylolpropane. Tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 2-trisacryloyloxymethylethylphthalic acid, propylene glycol di (meth) acrylate, number of propylene groups 2 To 14 polypropylene glycol di (meth) acrylates, dipentaerythritol penta (meth) acrylates, and dipentaerythritol hexa (meth) acrylates. These crosslinking agents can be used alone or in combination of two or more. The crosslinking agent may be used in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the matrix resin.

Additional composition

The quantum dot film of the present invention may further include additional materials for various purposes.

Ceramic nanoparticles are used as an additional material, which can be used in any one of quantum dot composites, encapsulating resins and matrix resins, preferably with quantum dots in a quantum dot composite.

Specifically, ceramic nanoparticles can be used together with quantum dots to minimize aggregation between quantum dots. That is, when there is a clustering phenomenon between quantum dots, the emission wavelength and half width (FWHM) change. Specifically, when two quantum dots are clustered, the size of the quantum dots increases, and as an example, the size of the quantum dots that convert blue light into green light is 2 nm to 2.5 nm. When two green light quantum dots are clustered, the size change from 4 nm to 5 nm quantum dots Since the wavelength and half-width (FWHM) of the generated and converted green light are increased, an accurate fluorescence effect does not appear.

The ceramic nanoparticles release heat generated during display driving or when quantum dots emit light to the outside (or matrix resin side) to prevent deterioration of the quantum dots, thereby increasing the reliability of the quantum dot film and increasing long-term stability.

In addition, ceramic nanoparticles have an effect of absorbing heat. As an example, when blue light is incident on the green quantum dot using the green quantum dot, it is converted into green light and emits light. During this process, some of the energy of the blue light is converted to heat, and the temperature of the quantum dots rises. In the case of quantum dots, the change in luminous efficiency with temperature is large. That is, when the quantum dot emits light, the luminous efficiency decreases as the ambient temperature increases, and vice versa. Accordingly, it is advantageous to lower the temperature in order to increase the luminous efficiency.

Accordingly, when ceramic nanoparticles are mixed and used, heat generated from the quantum dots is transferred (arrows) to the ceramic nanoparticles. As a result, the temperature of the quantum dots can be lowered because the ceramic nanoparticles absorb heat generated from the quantum dots, thereby improving stability.

The function of the ceramic nanoparticles as described above functions differently from that of the conventional ceramic particles to increase light conversion efficiency through light scattering.

For this effect, the ceramic nanoparticles may be included in any one or more of quantum dot composite, encapsulating resin and matrix resin, but preferably exert the above effect when encapsulated with quantum dots.

As the usable ceramic nanoparticles, one or more selected from the group consisting of oxides such as silica, alumina, titania, zirconia, tungsten oxide, zinc oxide, nitrides such as Si ₃ N ₄ , and semiconductor materials such as ZnSe can be used.

The ceramic nanoparticles are more preferably nanometer sized with an average particle diameter of 5 nm to 450 nm. If the size is less than the above-mentioned range, aggregation between particles occurs, and thus it is difficult to uniformly disperse. On the contrary, when it exceeds the above-mentioned range, the amount of quantum dots can be relatively reduced to lower the light conversion efficiency of the quantum dot film.

In addition, the content of the ceramic nanoparticles is 100 to 500 parts by weight compared to 100 parts by weight of quantum dots, preferably used in an amount of 150 to 400 parts by weight. When the content exceeds the above range, light absorption increases, resulting in a decrease in light conversion efficiency or a decrease in film non-uniformity and transparency.

In addition, as a material that can be added, a light scattering agent as described above is possible. At this time, the light scattering agent may be added to any of the quantum dot composite, encapsulating resin and matrix resin. In particular, when the light scattering agent is substantially positioned to be dispersed in the acrylic polymer together with the quantum dots, it is possible to maximize the scattering effect and thereby improve the wavelength conversion efficiency.

In addition, UV absorbers, light stabilizers, antioxidants, anti-yellowing agents, bluening agents, dispersants, flame retardants, dyes, fillers, organic or inorganic pigments, release agents, flow modifiers, leveling agents, antifoaming agents, thickeners, anti-settling agents, antistatic agents, anti-fogging agents Etc. can be suitably blended in a range that does not impair the effects of the present invention.

Manufacturing method

The quantum dot film according to the present invention is large

(S1) preparing a quantum dot composite;

(S2) preparing a photocurable composition comprising the quantum dot composite, a photocurable polymerization compound and a photoinitiator; And

(S3) It prepared by including the step of photo-irradiating the obtained photocurable coating composition.

Hereinafter, each step will be described in detail.

(S1) Preparation of quantum dot composite

The quantum dot composite is formed differently depending on the type of encapsulating resin.

As one example, when the encapsulating resin is a non-polar polyolefin-based wax, the following steps are performed.

a1) preparing a dispersion in which a surfactant is dispersed in a first solvent,

b1) adding a non-polar polyolefin-based wax, a quantum dot, an acrylic monomer, a photoinitiator and a second solvent having a repeating structure of Formula 1 and Formula 2 to the dispersion,

c1) encapsulating quantum dots by solidifying the non-polar polyolefin-based wax by heating and cooling the obtained composition; And

d1) is prepared by filtration to recover the encapsulated quantum dot complex.

As another example, when the encapsulating resin is an ultraviolet curing silicone resin, it is performed in the following steps.

a2) mixing a liquid UV-curable silicone-based resin, quantum dots, acrylic monomer, and photoinitiator,

b2) preparing a dispersion in which the surfactant is dispersed in the first solvent,

c2) adding a liquid UV-curable silicone resin, quantum dots, acrylic monomer, photoinitiator and second solvent mixed in the dispersion,

d2) encapsulating the obtained composition with ultraviolet light to encapsulate a quantum dot, an acrylic monomer, and a photoinitiator with a silicone resin, and

e2) recovering the encapsulated quantum dot complex after filtration.

As another example, when the encapsulating resin is a silicone resin of a thermal curing method, the following steps are performed.

a3) mixing a liquid thermosetting silicone-based resin, a quantum dot, an acrylic monomer, and a photoinitiator,

b3) preparing a dispersion in which the surfactant is dispersed in the first solvent,

c3) adding a liquid thermosetting silicone resin, a quantum dot, an acrylic monomer, a photoinitiator and a second solvent to the dispersion,

d3) encapsulating the silicone resin by applying heat to the obtained composition to encapsulate the quantum dot, acrylic monomer, and photoinitiator, and

e3) recovering the encapsulated quantum dot complex after filtration.

The first and second solvents of steps a1), b2), b3) and steps b1), c2) and c3) are phase-separated from each other by hydrophilicity / hydrophobicity, and the phase-separated hydrophobic regions are encapsulated resins, quantum dots, acrylic monomers, A photoinitiator and a second solvent are present.

As used herein, 'hydrophobic' refers to a substance exhibiting low intermolecular attraction to aqueous solvents such as water, and 'hydrophilicity' refers to a substance exhibiting high intermolecular attraction to aqueous solvents such as water. At this time, the criteria for the separation of the hydrophobicity and the hydrophilicity are relative to each other and are not particularly limited as long as they are phase-separated to form their respective regions.

Preferably, the first solvent is a hydrophilic solvent, preferably a hydrophilic polar solvent. Representative examples include water; It may be at least one selected from lower alcohols including methanol, ethanol, propanol, isopropanol, and butanol, preferably isopropanol, butanol, or a mixed solvent thereof.

Further, the second solvent is a hydrophobic solvent, and for example, a hydrophobic non-polar solvent is used. Representative examples include aliphatic hydrocarbon-based solvents including pentane, hexane, heptane, octane, decane, cyclochlorohexane and isoparaffin, aromatic hydrocarbon-based solvents including toluene, benzene, dichlorobenzene and chlorobenzene, tetrahydro Ether-based solvents including furan, 1,4-dioxane, and diethyl ether, and other ones selected from the group consisting of solvents such as methylene chloride are possible, and preferably toluene.

The surfactant is capable of forming micelles in the first solvent to form droplets, and a hydrophobic region is formed inside the droplet to form a non-polar polyolefin wax, quantum dots, acrylic monomers, photoinitiators, and second solvents. Exists.

As the usable surfactant, silicone-based, fluorine-based, ester-based, cationic-based, anionic-based, non-ionic-based, amphoteric surfactants, etc. can be preferably used. Specifically, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers , Polyethylene glycol diesters, sorbitan fatty acid esters, fatty acid-modified polyesters, tertiary amine-modified polyurethanes, polyethyleneimines, and the like.

The silicone-based surfactants include, for example, commercially available products such as DC3PA, DC7PA, SH11PA, SH21PA, SH8400 from Dow Corning Toray Silicone, and TSF-4440, TSF-4300, TSF-4445, TSF-4446, TSF- from GE Toshiba Silicone. 4460, TSF-4452, and the like.

The fluorine-based surfactant is, for example, commercially available products such as Mega Nippon F-470, F-471, F-475, F-482, F-489 of Dai Nippon Ink Chemical Co., Ltd. In addition, other commercially available products include KP (Shin-Etsu Chemical Co., Ltd.), PolyFlow (POLYFLOW) (Kyoisha Chemical Co., Ltd.), EFTOP (Tochem Products Co., Ltd.), Megapack (MEGAFAC) (Dani Nippon Ink Chemical Industry Co., Ltd.), Florad (Sumitomo 3M Co., Ltd.), Asahi guard, Surflon (above, Asahi Glass Co., Ltd.), SOLSPERSE (Lubrisol) , EFKA (EFKA Chemicals), PB 821 (Ajinomoto Co., Ltd.), Disperbyk-series (BYK-chemi), and the like.

Specific examples of the cationic surfactant include amine salts such as stearylamine hydrochloride and lauryl trimethylammonium chloride or quaternary ammonium salts.

Specific examples of the anionic surfactant include higher alcohol sulfate salts such as sodium lauryl alcohol sulfate ester or sodium oleyl alcohol sulfate, alkyl sulfates such as sodium lauryl sulfate or ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, And alkyl aryl sulfonates such as sodium dodecyl naphthalene sulfonate.

Specific examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene aryl ether, polyoxyethylene alkyl aryl ether, other polyoxyethylene derivatives, oxyethylene / oxypropylene block copolymer, sorbitan fatty acid ester, And polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, and polyoxyethylene alkylamines.

The surfactants exemplified above may be used alone or in combination of two or more, preferably CONION 275-90.

The surfactant is dispersed in a first solvent to form droplets, and non-polar polyolefin wax, quantum dots, acrylic monomer, photoinitiator and second solvent are present in the droplet. The droplets have a size of 0.1 μm to 100 μm, preferably 1 μm to 10 μm, and a first solvent is present outside the droplets.

The size of the droplets can be controlled according to the content ratio of each composition, and the content of the first solvent as an external phase and the composition of the internal phase of the droplets is 0.1: 99.9 to 20: 80, preferably 10: 90 to 5: 95 in weight ratio. You can. When the mixing ratio is out of the above range, droplets are not formed, or the distance between quantum dots is close, so that dispersion is inhibited and light conversion efficiency may decrease.

In addition, the size of the droplets can be controlled through the use of a surfactant. As the usable surfactant, a surfactant as described above can be used.

The photoinitiator is capable of photopolymerizing an acrylic monomer, and can be used irrespective of its type, as long as it can absorb light in the ultraviolet region having a wavelength of 100 nm to 400 nm to form radicals by decomposition of molecules.

Specifically, as the photoinitiator, a benzoin-based, hydroxy-ketone-based, aminoketone-based, or phosphine oxide-based photoinitiator may be used. Specifically, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylamino acetophenone, 2,2-dimethoxy -2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl -1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone , p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2- Methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylamino benzoic acid Ester, all High [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide can be used. It is not limited. The photoinitiator may be used alone or in a mixed form.

As the acrylic monomer, a monomer as described above may be used, and for example, a quantum dot dispersion in which quantum dots are dispersed in isobornyl acrylate may be used as it is. In addition, the isobornyl acrylate can be used alone or by mixing various acrylic monomers as described above.

The warming in step c1) is performed in a manner that heat is applied above the melting point of the non-polar polyolefin-based wax.

The melting point may vary depending on the type of wax, and the low-density polyethylene wax-based compound has a melting point of 80 ° C to 140 ° C, so it is liquefied by applying heat at this temperature.

When the heating is performed, the stirrer of the mixer is operated so that the micelles in the dispersion have a uniform size, and non-polar polyolefin wax, quantum dots, acrylic monomers, photoinitiators, and second solvents can be injected therein.

The stirring varies depending on the size of the mixer and the content of each composition, but may be stirred at a level of 100 to 5000 rpm. The mixing time is a level that can be uniformly mixed, and is usually performed for 1 minute to 30 minutes.

Next, the temperature of the mixer is lowered to solidify the non-polar polyolefin wax in a liquid state.

At this time, the cooling speed is controlled by gradually lowering the temperature of the mixer to room temperature to cool or quench it. When the cooling rate is fast, that is, when the temperature of the non-polar polyolefin-based wax in a liquid state is rapidly lowered, the size of the quantum dot complex formed by the non-polar polyolefin-based wax may decrease. Conversely, when the temperature is gradually decreased, the size of the quantum dot composite increases. You can. It is usually cooled at a rate of 0.1 ° C to 2 ° C per minute to stably produce a micron size.

Upon completion of cooling, a quantum dot, an uncured acrylic monomer, a photoinitiator, and a second solvent are present inside the capsule encapsulated with a non-polar polyethylene wax, and the quantum dot composite is a micron-meter spherical particle, and is independently made without aggregation between each other. It is dispersed in one solvent, that is, a dispersion.

For the next process, the quantum dot complex can be recovered and used through filtration, and if necessary, the particle size distribution of the quantum dot complex can be controlled using various sieves.

In addition, encapsulation is performed by irradiating the ultraviolet light of step d2).

Curing occurs through ultraviolet irradiation, and high-pressure mercury lamps, electrodeless lamps, ultra-high-pressure mercury lamps, carbon arc lamps, xenon lamps, LED lamps, metal halide lamps, chemical lamps, and black lights are used. In the case of the high-pressure mercury lamp, for example, it is performed under the conditions of 5 mJ / cm 2 to 3000 mJ / cm 2, specifically 400 mJ / cm 2 to 1500 mJ / cm 2. The irradiation time varies depending on the type of the light source, the distance between the light source and the coating film, the thickness of the coating film, and other conditions, but usually may be several seconds to several tens of seconds, and in some cases, 1 second of moisture.

In addition, encapsulation is performed by applying the heat of step d3).

Heat curing occurs by application of heat, which is carried out in a mixer equipped with a stirrer. The mixer is equipped with a temperature control device such as a heater that can increase the temperature for thermal curing. The temperature and time during the heat curing may vary depending on the type of the thermosetting resin, for example, in the case of silicone oil is performed for 1 hour to 5 hours at 100 ℃ to 125 ℃.

At this time, before the step d1), before the step e2), and before the step e3), the step of irradiating ultraviolet rays is performed to cure the acrylic monomer. In addition, by irradiation of ultraviolet light in d2), ultraviolet irradiation before e2) can be excluded if necessary.

The acrylic monomer starts polymerization of ultraviolet rays with a photoinitiator by irradiation with ultraviolet light, and is polymerized into an acrylic polymer. At this time, ultraviolet irradiation is performed by the same or the above-mentioned steps of d2) mentioned above.

By performing this ultraviolet irradiation step, quantum dots are dispersed in an acrylic polymer, and it is possible to obtain a particle-shaped quantum dot composite encapsulated with an encapsulating resin.

Next, the quantum dot complex is recovered through the filtration process of steps d1), e2) and e3).

On the other hand, according to another embodiment of the present invention, the quantum dot composite can be double encapsulated through the same or different resins from the encapsulating resin.

The double-encapsulated quantum dot composite more effectively blocks moisture or oxygen from the outside as it is encapsulated once more with an encapsulating resin to prevent oxidation of the quantum dots or lifting of both ends of the film to increase the light conversion efficiency of the quantum dots as well as increase the life of the quantum dot films. Can be increased.

In the double encapsulation, the first encapsulation and the second encapsulation of the quantum dot composite may use non-polar polyolefin-based waxes as described above, and use the same or similar resins.

Primary encapsulation and secondary encapsulation can be prepared in the manner described above. The thickness of the primary and secondary encapsulation is 0.1 to 10 μm, preferably 0.5 to 5 μm. Alternatively, 0.1 to 15 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the primary encapsulating resin. If the thickness or content is less than the above range, the probability that the quantum dot composite will not be encapsulated increases, resulting in a problem that is vulnerable to reliability. On the contrary, if it exceeds the above range, when the quantum dot composite is made of a wavelength conversion sheet and placed on a display device, it emits light. Since the problem of lowering uniformity occurs, it is appropriately used within the above range.

(S2) Preparation of photocurable composition

In this step, a photocurable composition comprising a photocurable polymerization compound and a photoinitiator is prepared in the quantum dot composite recovered in S1.

The photocurable polymerizable compound is for preparing a matrix resin, and is selected from the above and used.

The photoinitiator is for photocuring the photocurable polymerization compound, and the same or similar to the photoinitiator as described above is used. For example, when the photoinitiator and the photoinitiator are the same or similar to each other, the photocuring can be performed with only one light irradiation, thereby simplifying the process.

(S3) photocuring step

In this step, the photocurable composition obtained in S2 is irradiated with light to prepare a quantum dot film.

In order to prepare in the form of a film, after coating the photocurable composition on a substrate to form a coating film, it follows a method of performing light irradiation thereon.

The substrate can be a glass substrate or a plastic substrate. Preferably, a plastic substrate is used, and more preferably it can be a barrier film described later. Alternatively, the substrate is a plate-shaped substrate, a tubular substrate, or a substrate on which a light emitting diode is mounted, but is not limited thereto.

The coating method is not particularly limited in the present invention, and a known wet coating method can be used. For example, a method such as dip coating, flow coating, spray coating, roll coating, spin coating or gravure coating may be used to form a thin and uniform coating film, but is not limited thereto. When coating, the thickness of the coating film can be set in consideration of decreasing the thickness of the coating film after drying and after photocuring, and is set to a thickness of 1.5 to 5 times the final thickness. Thus, the coating can be performed one or more times.

Drying can be done by any method generally known in the art. Although drying is not limited to this, it can be performed by a hot air heating method or an induction heating method. In the case of the hot air heating method, the composition may be dried by heating at 40 to 80 ° C. for 10 to 50 seconds. In the case of the induction heating method, it can be performed for 5 to 20 seconds in a frequency range of 1 to 50 MHz and power of 1 to 15 KW. Through this drying, moisture or solvent remaining in the film is completely removed. The moisture or solvent degrades the physical properties of the quantum dot film.

The dried coating film has a structure in which quantum dot composites are uniformly dispersed in the form of particles in a matrix resin made of a photocurable polymerization compound. The photocurable polymerization compound and photocuring of the acrylic monomer in the quantum dot complex are simultaneously performed by irradiating light therewith.

Photocuring is performed by emitting active energy from a light source and irradiating the coating film.

As the light source, in addition to electromagnetic waves such as far-ultraviolet rays, ultraviolet rays, near-ultraviolet rays, infrared rays, X-rays, γ-rays, electron beams, proton rays, neutron beams, etc. may be used. Curing by ultraviolet irradiation is advantageous from the price and the like.

High-pressure mercury lamps, electrodeless lamps, ultra-high-pressure mercury lamps, carbon arc lamps, xenon lamps, LED lamps, metal halide lamps, chemical lamps, and black lights are used as the light source for ultraviolet irradiation. In the case of the high pressure mercury lamp, for example, it is carried out under conditions of about 5 mJ / cm 2 to about 3000 mJ / cm 2, specifically about 400 mJ / cm 2 to about 1500 mJ / cm 2.

The irradiation time varies depending on the type of the light source, the distance between the light source and the coating film, the thickness of the coating film, and other conditions, but may be a few seconds to several tens of seconds, and in some cases 1 second of moisture.

The quantum dot film prepared according to the above is dispersed in an acrylic polymer, the quantum dots are encapsulated with a non-polar polyolefin-based wax, the quantum dot composite again has a structure uniformly dispersed in the matrix resin.

The method according to the present invention can uniformly disperse quantum dots in a matrix resin in a high concentration compared to the conventional process, and enables stable production through encapsulation.

The quantum dot film of the present invention prepared by the above-described process technology comprises 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the matrix resin. Further, in the encapsulated particles, the quantum dots have a range of 0.1 to 10 parts by weight, preferably the encapsulating resin is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight.

The content ratio of the matrix resin, quantum dots and encapsulating resin is designed in consideration of characteristics such as uniform dispersion of quantum dots, light conversion efficiency, light transparency and strength of the quantum dot film. If the content of the quantum dots is less than the above range, the light conversion effect is insignificant and the light conversion efficiency is lowered. If the content is too excessive, uniform dispersion is difficult. In addition, when the content of the encapsulating resin is less than the above range, it is difficult to sufficiently encapsulate the quantum dots. Conversely, when the content is exceeded, the transparency of the quantum dot film is lowered.

Further, the quantum dot film according to the present invention has a thickness of 50 to 300 μm, preferably 70 to 180 μm. In particular, as the hydrophobic resin is used as the encapsulating resin, quantum dots can be effectively protected from moisture and air. In addition, the acrylic resin used as the matrix resin is excellent in adhesion to the substrate and the barrier film described later, and can effectively prevent the penetration of moisture or oxygen from the outside to prevent the oxidation of quantum dots. In addition, the quantum dot composite can be dispersed at a high content (ie, high concentration) at a level of 0.1 to 10 parts by weight, preferably 0.5 to 2 parts by weight, in the matrix resin, thereby further enhancing light conversion efficiency.

The quantum dot film can be applied to a wavelength conversion sheet for a display, and can realize a high color reproduction screen.

Wavelength conversion sheet

The quantum dot film according to the present invention can be used as a wavelength conversion sheet.

The term 'wavelength conversion sheet' referred to herein refers to a film capable of converting the wavelength of light emitted from a light source. In one example, when the light source emits blue light having a wavelength range between about 430 nm and about 470 nm, the blue light has green wavelength having a wavelength range between about 520 nm and about 560 nm and / or between about 600 nm and about 660 nm. It can be converted into red light having a wavelength band.

The wavelength conversion sheet according to an embodiment of the present invention has a structure in which a quantum dot film is disposed between a pair of polymer films.

The film is for supporting and protecting the quantum dot film, and more specifically, moisture or oxygen in external air is introduced into the quantum dot film to prevent oxidation of the quantum dot. Preferably, the film may be a barrier film, and may be a pair of films composed of a first barrier film and a second barrier film. At this time, the first and second barrier films may be the same or different from each other.

The film may be a polymer film comprising a polymer having high barrier to moisture and / or oxygen or a polymer film having a multilayer structure in which a barrier layer is formed.

The polymer film may be at least one selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cyclic olefin copolymer (COC), and cyclic olefin polymer (COP), preferably polyethylene tere Phthalate.

The barrier layer is an inorganic film or an organic-inorganic hybrid film on In, Sn, Pb, Au, Cu, Ag, Zr, Hf, Zn. A metal containing Al, Si, La, Ti, or Ni, an oxide thereof, a nitride thereof, an oxynitride thereof, or an acid fluoride thereof, and may be one or more selected from silicon oxide (SiXOY), silicon carbide oxide (SiXCYOZ). , Silicon oxide nitride (SiXOYNZ) and aluminum oxide (AlXOY). The inorganic film or the organic-inorganic hybrid film may be formed by various methods such as a sputtering process, a chemical vapor deposition process, or an evaporation method.

The polymer film has a moisture permeation rate of 10 ^-1 g / m ² / day to 10 ^-3 g / m ² / day under 37.8 ° C and 100% relative humidity, and at 23 ° C and 0% relative humidity, air permeability It is preferable that this is about 10 ^-1 cc / m ² / day / atm to about 10 ^-2 cc / m ² / day / atm.

In addition, the linear transmittance of the polymer film is preferably about 88% to 95% in the visible light region of 420nm to 680nm.

The wavelength conversion sheet according to the present invention can be manufactured using a photocurable composition as mentioned above between a pair of polymer films.

At this time, the wavelength conversion sheet is coated on any one of the pair of photocurable polymer films to form a coating film, the remaining polymer film is disposed on the coating film, and the polymer film is cured by irradiating light to cure the coating film. / Quantum dot coating layer / polymer film to produce a laminated wavelength conversion sheet.

The thus prepared wavelength conversion sheet has a total thickness of 70 µm to 300 µm, and a haze of 5% to 45%.

display

On the other hand, the quantum dot is capable of light emission, the wavelength conversion sheet of the present invention can be applied to the display.

Based on the LCD (Liquid Crystal Display), a display capable of high luminance and high color reproduction is realized by using light emission. Accordingly, in the case of an LCD panel, the wavelength conversion sheet may be applied to a back light unit (BLU). In the case of an LCD panel having a general structure, about 2/3 of light emitted from a backlight unit (BLU) is absorbed by a color filter, which is not good in terms of light conversion efficiency.

Accordingly, the display using the QD applied the wavelength conversion sheet of the present invention to the LCD panel and the backlight unit converts the blue light of the quantum dots in the film into green and red, respectively, and the blue light is partially transmitted to generate white light with high color purity. Due to this, high luminance and color reproducibility can be realized. In addition, the viewing angle is improved due to the isotropic light emission characteristics of the quantum dots, and the thickness of the liquid crystal can be reduced, thereby improving the response speed.

The display is not particularly limited in the present invention, and a backlight unit (BLU) of a display device such as a TV, monitor, tablet, smartphone, personal digital assistant (PDA), gaming device, electronic reading device or digital camera, etc. Applies to.

In addition, the wavelength conversion sheet of the present invention can be used for indoor or outdoor lighting, stage lighting, decorative lighting, accent lighting or museum lighting, etc., in addition, it can be used for special wavelength lighting required for horticulture, biology, etc. Applications that can be applied are not limited to the above.

[Example]

Hereinafter, the present invention will be illustrated through examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereby.

Example 1

A photocurable composition was prepared by performing the following steps, and a wavelength conversion sheet was prepared using the same.

(1) Preparation of quantum dot composite

500 ml of a mixed solvent of butanol / isopropanol (1: 1 volume ratio) was injected into a reactor equipped with a stirring device, and 0.1 g of polyoxyethylene lauryl ether (CONION 275-90, manufactured by New Japan Chemical Co.) was used as a surfactant. Was added.

To this, 25 g of toluene was added and 25 mg of a polyolefin-based wax, and 0.06 ml of a quantum dot dispersion dispersed in isobornyl acrylate, and 0.01 g of a photoinitiator (irgacure 184) were added, and the quantum dot dispersion was capped with octadecylamine. It was prepared by dispersing CdSe-based quantum dots (trade name: Nanodot-HE, Powerlogics, Korea) provided as an ping layer in isobornyl acrylate at a concentration of 20 mg / ml.

After raising the temperature of the reactor to about 110 ° C to melt the wax, the temperature of the reactor was lowered to room temperature while stirring at 100 rpm to prepare an encapsulated quantum dot composite. At this time, it was confirmed that the isobornyl acrylate in the quantum dot complex exists in an uncured state as a result of FT-IR measurement.

(2) Preparation of photocurable composition

In the mixer, 1.0 g of the quantum dot composite prepared in (1) and 0.01 g of a photoinitiator (irgacure 184) were added to 0.5 g of urethane acrylate oligomer and stirred to prepare a photocurable composition. Thereafter, toluene in the quantum dot complex was removed using a reduced pressure rotary concentrator.

(3) Wavelength conversion sheet production

The prepared photocurable composition was applied between a PET-based first barrier film (i-component, 50 μm) and a second barrier film (i-component, 50 μm), and the coating film had a light amount of 1000 mJ / cm ² . Cured by exposure to UV for 1 minute to prepare a wavelength conversion sheet. At this time, the thickness of the quantum dot film containing the quantum dot composite was 80 μm.

Example 2

A wavelength conversion sheet was prepared in the same manner as in Example 1, except that lauryl acrylate was used instead of isobornyl acrylate.

Example 3

A wavelength conversion sheet was prepared in the same manner as in Example 1, except that isobornyl acrylate / lauryl acrylate (1: 1 weight ratio) was used instead of isobornyl acrylate.

Example 4

(1) Preparation of quantum dot composite

500 ml of a mixed solvent of butanol / isopropanol (1: 1 volume ratio) was injected into a reactor equipped with a stirring device, and 0.1 g of polyoxyethylene lauryl ether (CONION 275-90, manufactured by New Japan Chemical Co.) was used as a surfactant. Was added.

Add 25 g of toluene to a separate glass bottle, followed by methylhydrogen. Silicone oil (TSF483, Toshiba Silicone Co., Ltd. Company product) 25 mg and quantum dot dispersion 0.06 ml (quantum dot 1.2 mg), isobornyl acrylate 10 mg was added and then injected into the reactor.

The resulting composition was stirred at 3,500 rpm, and the temperature was applied at 80 ° C. for 35 minutes to heat-cure the silicone oil to obtain a dispersion in which the quantum dot composite was dispersed. At this time, it was confirmed that the isobornyl acrylate in the quantum dot complex exists in an uncured state as a result of FT-IR measurement.

(2) Preparation of photocurable composition

To the mixer, 1.0 g of the quantum dot complex prepared in (1) and 0.01 g of a photoinitiator (irgacure 184) were added to 0.5 g of urethane acrylate oligomer, followed by stirring to prepare a photocurable composition. Thereafter, toluene in the quantum dot complex was removed using a reduced pressure rotary concentrator.

(3) Wavelength conversion sheet production

The prepared curable composition was applied between a PET-based first barrier film (i-component, 50 μm) and a second barrier film (i-component, 50 μm), and the coating film had a light amount of 1000 mJ / cm ² . Cured by exposure to UV for a minute to prepare a wavelength conversion sheet. At this time, the thickness of the quantum dot film containing the quantum dot composite was 80 μm.

Example 5

(1) Preparation of quantum dot composite

500 ml of a mixed solvent of butanol / isopropanol (1: 1 volume ratio) was injected into a reactor equipped with a stirring device, and 0.1 g of polyoxyethylene lauryl ether (CONION 275-90, manufactured by New Japan Chemical Co.) was added as a surfactant. Did.

After adding 25 g of toluene to a separate glass bottle, 25 mg of ultraviolet curing silicone (UV 9300, manufactured by Momentive Performance Materials) and 0.06 ml of quantum dot dispersion (1.2 mg of quantum dots) and 10 mg of isobornyl acrylate were added thereto. , It was injected into the reactor.

The obtained composition was irradiated with ultraviolet rays to irradiate ultraviolet rays with silicone to perform an encapsulation process. It was confirmed that the obtained isobornyl acrylate in the quantum dot composite was present in an ultraviolet cured state as a result of FT-IR measurement.

(2) Preparation of photocurable composition

To the mixer, 1.0 g of the quantum dot complex prepared in (1) and 0.01 g of a photoinitiator (irgacure 184) were added to 0.5 g of urethane acrylate oligomer, followed by stirring to prepare a photocurable composition. Thereafter, the solvent in the quantum dot complex was removed using a reduced pressure rotary concentrator.

(3) Wavelength conversion sheet production

The prepared curable composition was applied between a PET-based first barrier film (i-component, 50 μm) and a second barrier film (icomponent, 50 μm), and the coating film was coated with a light amount of 1000 mJ / cm ² for 1 minute. While curing by exposure to UV to prepare a wavelength conversion sheet. At this time, the thickness of the quantum dot film containing the quantum dot composite was 80 μm.

Comparative Example 1:

A solution in which 20 mg of CdSe-based quantum dots (trade name: Nanodot-HE, Powerlogics, Korea) is dispersed in 1 ml of toluene is added to an acrylic monomer, isobornly acrylate (IBOA), mixed, and then used by an evaporator Toluene was removed.

Subsequently, the solution was mixed with a urethane acrylate and photoinitiator (diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, TPO) purchased from BASF (company name, Germany). TPO was mixed with 0.8 parts by weight based on 100 parts by weight of the urethane acrylate to prepare a coating composition.

At this time, in the coating composition, with respect to 100 parts by weight of urethane acrylate, the capsule quantum dot was included 5 parts by weight.

On the first barrier film (i-component, Korea), the coating composition was coated with a thickness of 80 μm to form a coating layer. A wavelength barrier layer was formed by preparing a second barrier film substantially the same as the first barrier film to cover the second barrier film on the coating layer, and curing the coating layer by irradiating ultraviolet rays.

Comparative Example 2

(1) Photocurable colloid composition

After mixing 5 g of polyethylene wax (trade name: Licowax PED 136, Clariant, Switzerland) as a wax-based compound in 100 ml of toluene, the polyethylene wax was dissolved by raising the temperature to about 110 ° C to prepare a wax solution. A solution in which approximately 20 mg of CdSe-based quantum dots (trade name: Nanodot-HE, Powerlogics, Korea) is dispersed in 1 ml of toluene, added to the wax solution, mixed, cooled to room temperature, and the capsule quantum dots are dispersed. Was prepared.

The solution was mixed with urethane acrylate and photoinitiator (diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, TPO) purchased from BASF (company name, Germany). TPO was mixed at about 0.8 parts by weight with respect to 100 parts by weight of urethane acrylate. Thereafter, toluene was removed using a reduced pressure rotary concentrator to prepare a coating composition in which urethane acrylate, encapsulated quantum dots, and photoinitiator were mixed.

At this time, in the coating composition, with respect to 100 parts by weight of urethane acrylate, the capsule quantum dot contained about 5 parts by weight.

(2) Preparation of wavelength conversion sheet

On the first barrier film (i-component, Korea), a coating composition mixed with urethane acrylate, capsule quantum dots, and a photoinitiator was coated to a thickness of about 80 μm to form a coating layer.

A wavelength barrier layer was formed by preparing a second barrier film substantially the same as the first barrier film to cover the second barrier film on the coating layer, and curing the coating layer by irradiating ultraviolet rays.

Experimental Example 1: Quantum efficiency measurement

In order to confirm the quantum efficiency (QY: quantum yield) of the wavelength conversion sheet prepared in Examples and Comparative Examples, it was measured using an absolute quantum efficiency meter (trade name: C9920-02, HAMAMATSU, Japan). The measurement results are shown in Table 1 below.

division Quantum efficiency (%) Example 1 93% Example 2 90% Example 3 92% Example 4 89% Example 5 90% Comparative Example 1 85% Comparative Example 2 87%

Referring to Table 1, the quantum efficiency of the wavelength conversion sheet prepared according to the present invention showed a higher value than the wavelength conversion sheet of the comparative example.

The quantum efficiency is related to the compatibility between the matrix and the quantum dots, and when the quantum dots in the matrix are agglomerated, this causes a quenching effect due to the aggregation phenomenon, resulting in a problem of deterioration of quantum efficiency. The low quantum efficiency lowers the color purity, making it difficult to implement a desired color when applied to a display. Thus, the wavelength conversion sheets prepared in Examples 1 to 4 of the present invention are uniformly distributed throughout the matrix without aggregation and exhibit high quantum efficiency of at least 89%, and can exhibit high color purity when applied to a display.

Experimental Example 2: reliability characteristics

The optical properties of the wavelength conversion sheets prepared in Examples and Comparative Examples were measured.

A display in which a wavelength conversion sheet is disposed on a light emitting diode package including a blue light emitting diode, and two luminance enhancement films (BEF, 3M) and a reflective polarization film (DBEF, 3M) are disposed on the wavelength conversion sheet. In the apparatus, CIE 1931 color coordinates and luminance were measured using a spectroradiometer (Spectroradiometer, trade name: CS-2000, KONICA MINOLTA, Japan).

Subsequently, color coordinates and luminance were measured again under the following reliability conditions, and the difference was calculated. Reliability condition: High temperature (85 ℃ high temperature / high humidity (65 RH) @ 1,000hr

division Color coordinate CIE 1931 (x, y) Luminance (nit) Light conversion efficiency Example 1 (0.2230, 0.2092) 8514 68% Example 2 (0.2225, 0.2082) 8322 62% Example 3 (0.2243, 0.2091) 8425 65% Example 4 (0.2235, 0.2107) 8251 61% Example 5 (0.2222, 0.2088) 8342 63% Comparative Example 1 (0.2195, 0.2071) 7431 53% Comparative Example 2 (0.2184, 0.2087) 7553 57%

Referring to Table 2, when the wavelength conversion sheets of Examples 1 to 5 according to the present invention were mounted, the CIE 1931 color coordinate change was not large after the reliability test and the luminance deterioration was low.

The quantum dot composite according to the present invention, a quantum dot film and a wavelength conversion sheet having the same are applicable to displays.

Claims (21)

A quantum dot complex in which an acrylic monomer or a polymer thereof is dispersed and encapsulated with an encapsulating resin, wherein the acrylic monomer is an uncured liquid phase, and the polymer is an acrylic monomer photocured,
The acrylic monomer or polymer thereof contains 10 to 500 parts by weight based on 100 parts by weight of the quantum dot,
The encapsulating resin includes 10 to 600 parts by weight with respect to 100 parts by weight of quantum dots,
The acrylic monomer is isobornyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, norbornyl (meth) acrylate , Isodecyl (meth) acrylate, cyclohexyl (meth) acrylate, n-hexyl (meth) acrylate, adamantyl acrylate, acryloylmorpholine, tetrahydrofuryl (meth) acrylate, 2-phenoxy Ethyl (meth) acrylate, caprolactone (meth) acrylate and cyclopentyl acrylate is at least one selected from the group consisting of,
The encapsulating resin is a non-polar polyolefin-based wax having a repeating structure of Chemical Formulas 1 and 2 or a thermosetting silicone-based resin, quantum dot composite.
[Formula 1]
_{- [CH 2 -CH 2] a} -
[Formula 2]
-[CH ₂ -CHR ₁ ] _b-
(In the formulas 1 and 2, R ₁ is a C1 to C15 linear or branched alkyl group, 0.01≤b≤0.96, and satisfies a + b = 1.)
delete delete delete According to claim 1,
The encapsulating resin is a UV-curable silicone-based resin, a quantum dot composite.
According to claim 1,
The encapsulating resin is a thermosetting silicone-based resin, quantum dot composite.
According to claim 1,
A quantum dot composite further comprising ceramic nanoparticles on at least one of the quantum dot composite and the matrix resin.
A quantum dot film in which the quantum dot composite according to any one of claims 1, 5, 6, and 7 is dispersed in a matrix resin.
The method of claim 8,
In the matrix resin, one photocurable polymerizable compound selected from the group consisting of acrylic oligomers, acrylic monomers, and combinations thereof is photocured.
A wavelength conversion sheet in which the quantum dot film of claim 8 is interposed between a pair of polymer films.
The method of claim 10,
The polymer film is a wavelength conversion sheet comprising at least one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, cyclic olefin copolymer, and cyclic olefin polymer.
The method of claim 11,
In addition, In, Sn, Pb, Au, Cu, Ag, Zr, Hf, Zn on the polymer film. A wavelength conversion sheet in which one kind of barrier layer consisting of a metal containing Al, Si, La, Ti or Ni, an oxide thereof, a nitride thereof, an oxynitride thereof and an acid fluoride thereof is formed.
a1) preparing a dispersion in which a surfactant is dispersed in a first solvent,
b1) adding a non-polar polyolefin-based wax, a quantum dot, an acrylic monomer, a photoinitiator and a second solvent having a repeating structure of Formula 1 and Formula 2 to the dispersion,
c1) encapsulating quantum dots by solidifying the non-polar polyolefin-based wax by heating and cooling the obtained composition, and
d1) A method of manufacturing a quantum dot complex, wherein the quantum dot complex is encapsulated after filtration.
[Formula 1]
_{- [CH 2 -CH 2] a} -
[Formula 2]
-[CH ₂ -CHR ₁ ] _b-
(In the formulas 1 and 2, R ₁ is a C1 to C15 linear or branched alkyl group, 0.01≤b≤0.96, and satisfies a + b = 1.)
a2) mixing a liquid UV-curable silicone-based resin, quantum dots, acrylic monomer, and photoinitiator,
b2) preparing a dispersion in which the surfactant is dispersed in the first solvent,
c2) adding a liquid UV-curable silicone resin, quantum dots, acrylic monomer, photoinitiator and second solvent mixed in the dispersion,
d2) encapsulating the obtained composition with ultraviolet light to encapsulate a quantum dot, an acrylic monomer, and an initiator with a silicone resin, and
e2) A method for producing a quantum dot complex, wherein the quantum dot complex is encapsulated after filtration.
a3) mixing a liquid thermosetting silicone-based resin, a quantum dot, an acrylic monomer, and a photoinitiator,
b3) preparing a dispersion in which the surfactant is dispersed in the first solvent,
c3) adding a liquid thermosetting silicone resin, a quantum dot, an acrylic monomer, a photoinitiator and a second solvent to the dispersion,
d3) encapsulating the silicone resin by applying heat to the obtained composition to encapsulate the quantum dot, acrylic monomer, and photoinitiator, and
e3) A method for producing a quantum dot complex, wherein the quantum dot complex is encapsulated after filtration.
The method according to any one of claims 13 to 15,
A method of manufacturing a quantum dot composite, by performing a step of curing an acrylic monomer by performing a step of irradiating ultraviolet rays before step d1), before step e2), and before step e3).
The method according to any one of claims 13 to 15,
The first solvent is a polar solvent, the second solvent is a non-polar solvent, a method of manufacturing a quantum dot composite.
The method of claim 17,
The polar solvent is water; Method for producing a quantum dot composite, at least one selected from lower alcohols including methanol, ethanol, propanol, isopropanol, and butanol.
The method of claim 17,
The non-polar solvent is an aliphatic hydrocarbon-based solvent including pentane, hexane, heptane, octane, decane, cyclochlorohexane, and isoparaffin; Aromatic hydrocarbon-based solvents including toluene, benzene, dichlorobenzene and chlorobenzene; Ether-based solvents including tetrahydrofuran, 1,4-dioxane, and diethyl ether; Method for producing a quantum dot complex, at least one selected from the group consisting of methylene chloride and combinations thereof.
(S1) preparing a quantum dot composite according to any one of claims 13 to 15;
(S2) preparing a photocurable composition by mixing the quantum dot composite, a photocurable polymerization compound, and a photoinitiator; And
(S3) coating the obtained photocurable composition, followed by light irradiation to perform photocuring, a method of manufacturing a quantum dot film.
The method of claim 20,
The photocurable polymerizable compound comprises one selected from the group consisting of acrylic oligomers, acrylic monomers, and combinations thereof, a method of manufacturing a quantum dot film.