KR20170044796A - Resin composition and quantum dot sheet comprising the same - Google Patents

Abstract

Provided are a resin composition, and a quantum dot sheet including the same. The resin composition consists of: an acrylic binder; an aromatic oligomer including an aromatic ring having 6-30 carbon atoms on a main chain as well as a functional group having a double bond; a polyfunctional monomer; and a photoinitiator. According to the present invention, the resin composition exhibits outstanding oxygen/moisture blocking functions.

Description

RESIN COMPOSITION AND QUANTUM DOT SHEET COMPRISING THE SAME [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition and a quantum dot sheet comprising the same, and more particularly, to a resin composition and a quantum dot sheet containing the resin composition having excellent oxygen and moisture barrier properties.

The Quantum Dot (QD) is a nano-sized semiconductor particle. Since quantum dots are very small, quantum confinement effects appear. The quantum confinement effect refers to a phenomenon in which the band gap of an object becomes larger when the object becomes smaller than a nano-size. Accordingly, when light having a wavelength larger than the bandgap of the quantum dots is incident on the quantum dots, the quantum dots absorb the light and become excited and emit light of a specific wavelength and fall to the ground state. The wavelength of the emitted light has a value corresponding to the band gap. Quantum dots vary in their luminescent properties due to the quantum confinement effect depending on their size and composition, and thus they have been widely used in various light emitting devices and electronic devices.

A quantum dot liquid crystal display (QD-LCD) having excellent color reproducibility can be produced using quantum dots. The quantum dot is used as a phosphor in a display device. In order to optically couple a light source and a quantum dot, a sheet produced by dispersing a quantum dot in a polymer resin (hereinafter referred to as a quantum dot sheet) is used.

Specifically, in a general quantum dot liquid crystal display, a backlight unit (BLU) has a structure in which a quantum dot sheet is laminated on a light guide plate. Light emitted from the light source is diffused in the light guide plate, and light diffused in the light guide plate is incident on the quantum dot sheet in the upward direction. The incident light passes through the quantum dots dispersed in the quantum dot sheet, whereby the wavelength of the light is converted.

1 is a schematic cross-sectional view of a quantum dot sheet used in a conventional quantum dot liquid crystal display. Referring to FIG. 1, a quantum dot sheet 100 includes a plurality of quantum dots 100, a plurality of light scattering agents 120, a polymer resin 130, and a barrier layer 140. The quantum dot sheet 100 has a structure in which a plurality of quantum dots 100 and a plurality of light scattering agents 120 are dispersed in the polymer resin 130

At this time, the polymer resin 130 protects the quantum dots 110 from external shocks and environment, and disperses and fixes the quantum dots 110 and the light scattering agent 120. The polymer resin 130 functions as an important factor for determining the reliability, cost, and performance of the quantum dot sheet 100. In order to increase the light extraction efficiency of the quantum dot 110 and ensure the reliability of the quantum dot sheet 100, the polymer resin 130 is required to have high refractive index, oxygen and moisture barrier properties, and excellent heat resistance.

The general polymer resin 130 used in the conventional quantum dot sheet 100 is an epoxy resin. Although epoxy resin is inexpensive and has excellent properties as an encapsulating material for optical members, it has a limitation in that it is insufficient to be applied to a high efficiency light source device such as a quantum dot liquid crystal display due to low blocking power of oxygen and moisture and yellowing phenomenon at high temperature .

The conventional quantum dot sheet 100 includes a polymer resin 130 including a quantum dot 110 and a light scattering agent 120 in order to compensate for the disadvantage of the polymer resin 130 used in the quantum dot sheet 100 such as epoxy resin. And a pair of barrier layers 140 surrounding upper and lower portions of the barrier layer 140. The barrier layer 140 is formed of a material having low oxygen permeability and moisture permeability and a material having excellent heat resistance so that quantum dots susceptible to oxygen, moisture and the like can be protected from external environments such as heat, oxygen, and moisture. For example, the barrier layer 140 may be an inorganic material such as silicon oxide or metal oxide.

However, since the conventional barrier layer 140 is subjected to a separate additional process to fabricate the quantum dot sheet 100, there is a problem that the manufacturing efficiency of the quantum dot sheet 100 is lowered and the manufacturing cost is increased. Therefore, development of a quantum dot sheet that does not include a separate barrier layer is required to be developed, and development of a polymer resin for a quantum dot sheet which is excellent in the blocking power of oxygen and moisture is required in order to satisfy such a structure.

[Related Patent Literature]

1. Korean Patent Publication No. 2013-0133994 (entitled "Optical Member, Light Emitting Device and Display Device)

Accordingly, a problem to be solved by the present invention is to provide a photocurable resin composition excellent in oxygen and moisture barrier properties.

Another object of the present invention is to provide a quantum dot sheet using a resin composition having excellent oxygen and moisture barrier properties and to provide a quantum dot sheet capable of protecting quantum dots from an external environment without a separate barrier layer.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In order to solve the above problems, a photocurable coating composition according to an embodiment of the present invention comprises an acrylic binder, an aromatic ring containing a C ₆ -C ₃₀ aromatic ring in the main chain, An oligomer, a polyfunctional monomer, and a photoinitiator.

According to another aspect of the present invention, the aromatic oligomer may include at least 10 functional groups.

According to still another aspect of the present invention, at least one of the acrylic binder and the aromatic oligomer may further include a functional group having a polarity capable of ionic bonding with water molecules.

According to another aspect of the present invention, there is provided a quantum dot sheet comprising a quantum dot, a light scattering agent and a polymer resin, wherein the polymer resin comprises an acrylic binder, a C ₆ -C ₃₀ aromatic ring Wherein the resin composition comprises an aromatic oligomer having a functional group containing a double bond, a polyfunctional monomer and a photoinitiator, and the polymer resin comprises a repeating unit represented by the following formula (1).

[Chemical Formula 1]

In Formula (1), Ar is a C ₆ -C ₃₀ aryl group, and B is a substituted or unsubstituted C ₁ -C ₁₀₀₀ alkyl group.

According to another feature of the present invention, the polymer resin may have an average interatomic distance of 0.2 nm to 2.0 nm.

INDUSTRIAL APPLICABILITY The present invention has an effect of providing a resin composition excellent in oxygen and moisture barrier properties.

Further, the present invention has an effect of providing a quantum dot sheet capable of protecting quantum dots from an external environment without a separate barrier layer by using a cured polymer resin.

1 is a schematic cross-sectional view of a quantum dot sheet used in a conventional quantum dot liquid crystal display.
2 is a schematic cross-sectional view of a quantum dot sheet according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. In addition, the size and thickness of each component shown in the drawings are shown for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the components shown in the drawings.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other partially or entirely and technically various interlocking and driving is possible as will be appreciated by those skilled in the art, It may be possible to cooperate with each other in association.

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

2 is a schematic cross-sectional view of a quantum dot sheet according to an embodiment of the present invention.

Referring to FIG. 2, the quantum dot sheet 200 includes a plurality of quantum dots 110, a plurality of light scattering agents 120, and a polymer resin 230. The plurality of quantum dots 110 and the plurality of light scattering agents 120 are dispersed in the polymer resin 230. The quantum dot sheet 200 converts light incident from a light source into light of a desired wavelength. Illustratively, if the incident light is blue light having a wavelength band between about 430 nm and about 470 nm, the quantum dot sheet 200 absorbs blue light and emits green light in a wavelength range of about 520 nm to about 560 nm. The blue light can be converted into the green light including the green light 100G. The quantum dot sheet 200 may further include a quantum dot 100R that absorbs blue light and emits red light having a wavelength between about 630 nm and about 660 nm to convert blue light into red light.

The quantum dot sheet 200 according to an embodiment of the present invention uses a polymer resin 230 having excellent oxygen and moisture barrier properties and does not require a separate barrier layer unlike the conventional quantum dot sheet. Feature.

Hereinafter, the quantum dot 110, the light scattering agent 120 and the polymer resin 230 included in the quantum dot sheet 200 of the present invention will be described in detail.

Qdot

The quantum dot 110 is a semiconductor particle having a diameter of several nanometers. The quantum dot 110 may include a core, a shell surrounding the core, and an inorganic ion ligand around the core and the shell.

The core emits light of a specific wavelength at the center of the quantum dot 110. The shell may be formed by wrapping the core at the surface of the core to protect the core.

The core and shell are formed of II-VI, III-V, IV-VI, and IV semiconductor materials or compounds thereof on the periodic table. For example, the II-VI group semiconductor compound may be the elemental compound of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe or a combination thereof. The III-V semiconductor compound may be GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb or a combination thereof. The IV-VI group semiconductor compound may be SnS, SnSe, SnTe, PbS, PbSe, PbTe, or a combination thereof. Group IV elements or compounds may be Si, Ge, SiC, SiGe, or a combination thereof. In addition, the semiconductor compound may be a trivalent compound including a Group II-VI, III-V, IV-VI, or IV group element or a mesoporous compound on the periodic table. Further, the semiconductor material or compound is not limited to those described above, and may be any semiconductor material or compound known to those skilled in the art.

The inorganic ion ligand includes a halogen group or a chalcogen group element. Or monatomic ions of these elements or polyatomic ions containing these elements.

Light scattering agent

Referring to FIG. 2, the quantum dot sheet 200 includes a plurality of light scattering members 120, which are particles formed such that the surface has a predetermined curvature.

The light scattering agent 120 spreads the light in various directions in the quantum dot sheet 200, thereby increasing the area where the incident light and the quantum dot 110 meet.

The light scattering agent 120 may be formed of a metal oxide particle, an air bubble, a glass bead, or a polymer bead, and may be formed of a mixed mixture thereof. The light scattering agent 120 is not limited to the above-described materials and may be formed of any material known to those skilled in the art.

The light scattering agent 120 formed of such materials may have a relatively high or low refractive index with respect to the polymer resin 230 to be described later. For example, the ratio of the refractive index of the light scattering agent 120 to the polymer resin 230 may be in the range of about 0.3 to 2.0. Due to such a difference in refractive index, the light-scattering agent 120 can change the path of light incident on the light conversion layer and diffuse the emitted light.

The light scattering agent 120 preferably has a spherical shape as a whole, but may have an elliptical shape, a distorted shape, or any other unintended shape other than a spherical shape in actual manufacture.

Polymer resin

Referring to FIG. 2, the polymer resin 230 protects the quantum dots 110 from external impacts and the environment, and disperses and fixes the quantum dots 110 and the light scattering agent 120. Specifically, the polymer resin 230 of the present invention is excellent in oxygen and moisture barrier properties and protects the quantum dot 110 from the external environment. The polymer resin 230 surrounds the quantum dot 110 and disperses the quantum dot 110 uniformly in the quantum dot sheet 200.

At this time, the polymer resin 230 of the present invention is a compound cured from the photo-curable resin composition. More specifically, the photo-curing resin composition includes an acrylic binder, an aromatic oligomer, a polyfunctional monomer and a photoinitiator.

The type of the acrylic binder is not particularly limited as far as it has an acrylate functional group. For example, an acrylate monomer, an acrylate oligomer, or a mixture thereof may be used. At this time, the acrylate monomer or acrylate oligomer contains at least one acrylate functional group capable of participating in the curing reaction.

As the acrylate oligomer, a urethane acrylate oligomer, an epoxy acrylate oligomer, a polyester acrylate, a polyether acrylate or a mixture thereof may be used. Examples of the acrylate monomers include dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, trimethylene propyl triacrylate, propoxylated glycerol triacrylate 1,6-hexanediol diacrylate, propoxylated glycerol triacrylate, tripropylene glycol diacrylate, ethylene glycol diacrylate, or a mixture thereof, and the like are preferable But is not limited thereby. The acrylic binder may be a copolymer of two or more compounds containing an acrylate functional group.

The weight average molecular weight of the acrylic binder according to the present invention is preferably in the range of 5,000 to 50,000, more preferably in the range of 10,000 to 30,000. When the weight average molecular weight of the acrylic binder is less than 5,000, physical properties such as basic heat resistance, chemical resistance, mechanical strength and adhesiveness to adjacent layers required for the quantum dot sheet 200 formed can not be satisfied. When the weight average molecular weight of the acrylic binder exceeds 50,000, viscosity becomes excessively high and it is difficult to disperse the quantum dot 110 and the light scattering agent 120 appropriately and the uniformity of the thickness of the quantum dot sheet 200 is deteriorated.

On the other hand, the acrylic binder may further include a functional group having a polarity capable of ionic bonding with water molecules at the terminal. When the acrylic binder further contains a functional group having polarity, the moisture permeation performance can be further improved due to surface adsorption of moisture. Although not limited thereto, the functional group having a polarity may include a hydroxy group or an acrylic group.

The acrylic binder may be contained in an amount of 10% by weight to 60% by weight in the photocurable resin composition. If the content of the acrylic binder is less than 10% by weight, photo-curing may not occur sufficiently. If the content of the acrylic binder is more than 60% by weight, the processability may be lowered or the physical properties of the cured polymer resin 230 may be deteriorated.

The aromatic oligomer imparts oxygen and moisture barrier properties to the quantum dot sheet 200 of the present invention. Specifically, the aromatic oligomer can prevent penetration of oxygen and moisture by narrowing the average distance between atoms of the photopolymerized polymer resin 230. The aromatic oligomer also controls the curing of the quantum dot sheet 200 of the present invention and controls the flexibility of the quantum dot sheet 200. In addition, the oligomer serves to disperse and fix the quantum dot 110 and the light scattering agent 120 contained in the quantum dot sheet 200.

Specifically, the aromatic oligomer contains an aromatic ring in the main chain. The aromatic oligomer is a compound which can be photo-cured with an acrylic binder or a monomer, and includes a functional group containing a double bond. More specifically, the aromatic oligomer includes a vinyl group or an acrylate group as a functional group. At this time, the vinyl group or acrylate group may be a structure directly substituted on the aromatic ring, or may be a structure substituted with an alkyl group connected to an aromatic ring. The vinyl group or the acrylate group contained in the aromatic oligomer reacts with the functional group of the acrylic binder or the polyfunctional monomer to be condensed, thereby forming the polymer resin 230 having a chain structure.

At this time, the aromatic oligomer preferably has 10 or more functional groups including a double bond, more preferably 15 or more. When the number of functional groups including a double bond such as a vinyl group or an acrylate group is 10 or more, the curing degree of the aromatic oligomer and the acrylic binder or monomer is improved, and the average distance between atoms of the polymer resin 230 is It can be as small as it is difficult. That is, the aromatic oligomer can be more tightly bonded and cured with the acrylic binder or the monomer.

On the other hand, as described above for the acrylic binder, the aromatic oligomer may further include a functional group having a polarity capable of ionic bonding with water molecules at the terminal. When the acrylic binder further contains a functional group having polarity, the moisture permeation performance can be further improved due to surface adsorption of moisture. At this time, the functional group having polarity may be formed by substituting a part of the functional group including the double bond of the aromatic oligomer.

The aromatic oligomer may be contained in an amount of 40 to 80% by weight in the photocurable resin composition. When the content of the acrylic binder is less than 40% by weight, the average distance between atoms of the polymer resin 230 formed by curing the photocurable resin composition is increased, and penetration of oxygen molecules and water molecules is difficult to prevent. When the content of the acrylic binder is more than 80% The resin composition may not be cured properly.

The purpose of the polyfunctional monomer is to impart dispersion stability of the quantum dot 110 and the light scattering agent 120 and impart appropriate viscosity, in addition to the basic purpose of imparting photopolymerization to the photocurable resin composition.

The polyfunctional monomer is a compound that can be photo-curable together with the photo-curable binder or aromatic oligomer described above, and may preferably include a compound having an acrylate group having 3 to 15 functional groups.

The polyfunctional monomer may be a hydroxyl group-containing acrylate-based compound such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, pentaerythritol triacrylate or dipentaerythritol pentaacrylate; Water-soluble acrylate compounds such as polyethylene glycol diacrylate and polypropylene glycol diacrylate; Polyfunctional polyester acrylate compounds of polyhydric alcohols such as trimethylolpropane triacrylate, pentaerythritol tetraacrylate or dipentaerythritol hexaacrylate; Acrylate compounds of polyfunctional alcohols such as trimethylol propane and hydrogenated bisphenol A, or ethylene oxide adducts and / or propylene oxide adducts of polyhydric phenols such as bisphenol A and biphenol; A polyfunctional or monofunctional polyurethane acrylate which is an isocyanate-modified product of the hydroxyl group-containing acrylate compound; An epoxy acrylate-based compound which is a (meth) acrylic acid adduct of bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether or phenol novolac epoxy resin; Caprolactone-modified acrylate compounds such as caprylactone-modified ditrimethylolpropane tetraacrylate, ε-caprolactone-modified dipentaerythritol acrylate, and caprolactone-modified hydroxypivalic acid neopentyl glycol ester diacrylate. These may be used alone or in combination of two or more.

 Particularly preferred are pentaerythritol triacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and caprolactone-modified ditrimethylol propane tetraacrylate.

The content of the polyfunctional monomer may be 5 wt% to 30 wt%, preferably 7 wt% to 20 wt%, based on the total weight of the photocurable resin composition. When the content of the polyfunctional monomer is less than 5% by weight, the photo-curing may be insufficient. When the content is more than 30% by weight, the physical properties of the cured polymer resin 230 may be deteriorated.

On the other hand, the photocurable resin composition of the present invention includes a photoinitiator so as to be cured by ultraviolet rays. The type of the photoinitiator is not particularly limited as long as it is a commonly used ultraviolet curing initiator, and examples thereof include 1-hydroxycyclohexyl phenyl ketone, benzyl dimethyl ketal, hydroxydimethylacetophenone, benzoin, benzoin methyl ether, benzoin Ethyl ether, benzoin isopropyl ether, and benzoin butyl ether. Further, photoinitiators such as Daracur 1173, Irgacure 184 and Irgacure 907 (Ciba) may be used.

The photoinitiator may be contained in an amount of 0.1 wt% to 10 wt%, preferably 1 wt% to 5 wt%, based on the total photo-curable resin composition. If the content of the photoinitiator is less than 0.1% by weight, the photocuring will not occur properly. If the content of the photoinitiator is more than 10% by weight, the transmittance of the quantum dot sheet 200 will be lowered and the quantum dot 110 and the light- .

On the other hand, the photocurable resin composition of the present invention may contain one or more solvents to impart appropriate solubility and viscosity.

There are no particular restrictions on the type of the organic solvent to be used, but the organic solvent may be selected from among benzene, toluene, methyl ethyl ketone, methyl isobutyl ketone, acetone, ethanol, tetrahydrofurfuryl alcohol, propyl alcohol, propylene carbonate, N-methylpyrrolidone, N-vinylpyrrolidinone, N-acetylpyrrolidinone, N-hydroxymethylpyrrolidinone, N-butylpyrrolidinone, N- (N-dodecyl) pyrrolidinone, 2-methoxyethyl ether, xylene, cyclohexane, 3-methylcyclohexanone, ethyl acetate, butyl acetate, tetrahydrofuran, methanol, amyl propionate, Propylene glycol methyl ether, diethylene glycol monobutyl ether, dimethyl sulfoxide, dimethyl formamide, ethylene glycol, hexafluoroantimonate, monoalkyl ether of ethylene glycol, and ethyl It may include at least one selected from the group consisting of dialkyl ethers of glycols.

Meanwhile, the photocurable resin composition of the present invention may further include other additives capable of removing bubbles or dissipating charge of the photocurable resin composition.

The polymer resin 230 of the present invention formed by curing the above-mentioned photo-curable resin composition is preferably an acrylic resin containing an aromatic ring in the main chain. At this time, the polymer resin 230 may include a repeating unit represented by the following formula (1).

[Chemical Formula 1]

In Formula 1, Ar is a C ₆ -C ₃₀ aryl group, and B is a substituted or unsubstituted C ₁ -C ₁₀₀₀ alkyl group.

B is preferably C ₂ -C ₂₀ , more preferably C ₂ -C ₅ , in view of the fact that, in the above formula (1), the average distance between the average atoms of the polymer resin 230 should be appropriately adjusted.

The polymer resin 230 preferably has an average distance between atoms of 0.2 nm to 3.0 nm, more preferably 0.3 nm to 1.0 nm. The average molecular distance between the molecules of the polymer resin 230 is smaller than that of the oxygen molecules and water molecules so that oxygen molecules and water molecules are dispersed in the quantum dot sheet 200, It is possible to suppress penetration into the inside.

The polymer resin 230 of the present invention is a cured resin containing an aromatic oligomer having an aromatic ring in its main chain, and the average distance between atoms of the polymer resin 230 is small as compared with the conventional resin used for the quantum dot sheet . Since the polymer resin 230 has an average distance between atoms that is smaller than the diameter of oxygen molecules and water molecules in whole or in part, when oxygen molecules and water molecules are used in the quantum dot sheet 200, Can be suppressed. Accordingly, the quantum dot sheet 200 including the polymer resin 230 described above can minimize the luminance decrease over time and improve the light emission efficiency.

As a result, the polymer resin 230 of the present invention can exhibit sufficient permeation-preventing performance of oxygen molecules and water molecules by itself, and therefore, a separate barrier layer is not required unlike the quantum dot sheet used in the conventional quantum dot liquid crystal display . Therefore, the manufacturing process can be reduced and the unit cost of the product can be reduced.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

200 quantum dot sheet
110 quantum dot
120 Light scattering agent
230 Polymer resin

Claims (5)

Acrylic binders;
Aromatic oligomers containing a C ₆ -C ₃₀ aromatic ring in the main chain and containing a functional group containing a double bond;
Multifunctional monomers; And
A photocurable resin composition comprising a photoinitiator. The method according to claim 1,
Wherein the aromatic oligomer comprises at least 10 functional groups. The method according to claim 1,
Wherein at least one of the acrylic binder and the aromatic oligomer further comprises a functional group having a polarity capable of ionic bonding with water molecules. In a quantum dot sheet comprising a quantum dot, a light scattering agent and a polymer resin,
Wherein the polymer resin comprises an acrylic binder, an aromatic oligomer having a C ₆ -C ₃₀ aromatic ring in its main chain and containing a functional group containing a double bond, a multifunctional monomer; And a photoinitiator are cured,
Wherein said polymer resin comprises a repeating unit represented by the following formula (1).
[Chemical Formula 1]

In Formula 1, Ar is a C ₆ -C ₃₀ aryl group, and B is a substituted or unsubstituted C ₁ -C ₁₀₀₀ alkyl group. 5. The method of claim 4,
Wherein the polymer resin has an average distance between atoms of 0.2 nm to 2.0 nm.

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