JP2020101803A - Wavelength conversion member, backlight unit, image display device, and curable composition - Google Patents

Abstract

To provide a wavelength conversion member which contains a quantum dot phosphor and offers superior light resistance and moist heat resistance in high-temperature environments.SOLUTION: A wavelength conversion member provided herein comprises a cured product obtained by curing a curable composition containing at least a quantum dot phosphor and a polyfunctional thiol compound, where a thiol group of the cured product exhibits a reaction rate of 15% to 65%.SELECTED DRAWING: None

Description

The present invention relates to a wavelength conversion member, a backlight unit, an image display device and a curable composition.

In recent years, in the field of image display devices such as liquid crystal display devices, it has been required to improve color reproducibility of displays. As a means for improving color reproducibility, a wavelength conversion member containing a quantum dot phosphor has been attracting attention, as described in Japanese Patent Publication No. 2013-544018 and International Publication No. 2016/052625.

The wavelength conversion member including the quantum dot phosphor is arranged, for example, in the backlight unit of the image display device. When using a wavelength conversion member including a quantum dot phosphor that emits red light and a quantum dot phosphor that emits green light, when the wavelength conversion member is irradiated with blue light as excitation light, the quantum dot phosphor emits light. White light can be obtained by the red light and the green light thus generated and the blue light transmitted through the wavelength conversion member. With the development of the wavelength conversion member containing the quantum dot phosphor, the color reproducibility of the display has been expanded from the conventional NTSC (National Television System Committee) ratio of 72% to the NTSC ratio of 100%.

The wavelength conversion member containing the quantum dot phosphor usually has a cured product obtained by curing a curable composition containing the quantum dot phosphor. The curable composition includes a thermosetting type and a photocurable type, and from the viewpoint of productivity, a photocurable type curable composition is preferably used.

By the way, in a wavelength conversion member containing a quantum dot fluorescent substance, at least one copy of a hardened material containing a quantum dot fluorescent substance may be covered with a coating material. For example, in the case of a film-shaped wavelength conversion member, a coating material may be provided on one side or both sides of a cured product containing a quantum dot phosphor.

However, depending on the type of coating material, the oxygen transmission rate is high, and the quantum dot phosphor is prone to deterioration under the influence of oxygen, especially when exposed to light in a high temperature environment, when left in a high temperature and high humidity environment, etc. In addition, the quantum dot phosphor may deteriorate and the emission intensity may decrease.

The present disclosure has been made in view of the above circumstances, and includes a quantum dot phosphor, a wavelength conversion member having excellent light resistance and wet heat resistance in a high temperature environment, and a backlight unit and an image display device using the same. The purpose is to provide.
An object of the present disclosure is to provide a curable composition containing a quantum dot phosphor and capable of producing a wavelength conversion member having excellent light resistance and wet heat resistance in a high temperature environment.

The specific means for achieving the above object are as follows.
<1> A cured product obtained by curing a curable composition containing at least a quantum dot phosphor and a polyfunctional thiol compound, and the thiol group reaction rate of the cured product is 15% to 65%. , Wavelength conversion member.
<2> Between the peak area (V4) attributed to the SH stretching vibration and the peak area (V5) attributable to the CH stretching vibration in the cured product measured with a Fourier transform infrared spectrophotometer The wavelength conversion member according to <1>, in which the ratio (V4/V5) is 0.015 to 0.060.
<3> The wavelength conversion member according to <1> or <2>, in which the cured product has an alkyleneoxy structure.
<4> The cured product is obtained by curing the curable composition further containing a polyfunctional (meth)acrylate compound, and the reaction rate of carbon-carbon double bonds of the cured product is 90% or more, <1. > To <3>, the wavelength conversion member according to any one of.
<5> The wavelength conversion member according to <4>, wherein the polyfunctional (meth)acrylate compound has an alkyleneoxy group.
<6> The wavelength conversion member according to <5>, wherein the polyfunctional (meth)acrylate compound has 2 to 5 (meth)acryloyl groups in one molecule.
<7> The wavelength conversion member according to any one of <1> to <6>, in which the quantum dot phosphor contains a compound containing at least one of Cd and In.
<8> The wavelength conversion member according to any one of <1> to <7>, further including a coating material that covers at least a part of the cured product.
<9> Any one of <1> to <8>, in which the cured product has a sulfide structure bonded to two carbon atoms, and the two carbon atoms bonded to the sulfide structure are both primary carbon atoms. The wavelength conversion member according to any one of the above.

<10> A backlight unit including the wavelength conversion member according to any one of <1> to <9> and a light source.

<11> An image display device including the backlight unit according to <10>.

<12> A quantum dot phosphor, a polyfunctional (meth)acrylate compound, and a thiol compound are included, the thiol compound includes a polyfunctional thiol compound, and the polyfunctional thiol compound is a thiol to which a primary carbon atom is bonded. The ratio of the total number of thiol groups in the thiol compound to the total number of carbon-carbon double bonds in the polyfunctional (meth)acrylate compound having at least one group (total number of thiol groups/carbon-carbon double bond). Curable composition whose total number of bonds) is from 0.5 to 4.0.
<13> A quantum dot phosphor, a polyfunctional (meth)acrylate compound, and a thiol compound are included, the thiol compound includes a polyfunctional thiol compound, and the polyfunctional (meth)acrylate compound is two per molecule. A ratio of the total number of thiol groups in the thiol compound to the total number of carbon-carbon double bonds in the polyfunctional (meth)acrylate compound having 5 to 5 (meth)acryloyl groups (total number of thiol groups /Total number of carbon-carbon double bonds) is 0.5 to 4.0.
<14> The curable composition according to <12>, wherein the polyfunctional (meth)acrylate compound has 2 to 5 (meth)acryloyl groups in one molecule.
<15> The curable composition according to <13>, wherein the polyfunctional thiol compound has at least one thiol group bonded with a primary carbon atom.
<16> The curable composition according to any one of <12> to <15>, in which the polyfunctional (meth)acrylate compound has an alkyleneoxy group.

According to the present disclosure, it is possible to provide a wavelength conversion member that includes a quantum dot phosphor and is excellent in light resistance and wet heat resistance in a high temperature environment, and a backlight unit and an image display device using the same.
According to the present disclosure, it is possible to provide a curable composition containing a quantum dot phosphor and capable of producing a wavelength conversion member having excellent light resistance and wet heat resistance in a high temperature environment.

It is a schematic cross section which shows an example of a schematic structure of a wavelength conversion member. It is a figure which shows an example of a schematic structure of a backlight unit. It is a figure which shows an example of a schematic structure of a liquid crystal display device.

Hereinafter, modes for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and does not limit the present invention.
In the present disclosure, the numerical range indicated by using "to" includes the numerical values before and after "to" as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another stepwise described numerical range. .. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
In the present disclosure, each component may include a plurality of types of corresponding substances. When there are multiple types of substances corresponding to each component in the composition, the content rate or content of each component is the total content rate or content of the multiple types of substances present in the composition unless otherwise specified. Means quantity.
In the present disclosure, a plurality of types of particles corresponding to each component may be included. When a plurality of types of particles corresponding to each component are present in the composition, the particle size of each component means a value for a mixture of the plurality of types of particles present in the composition unless otherwise specified.
In the present disclosure, the term “layer” or “film” means that when the region in which the layer or film is present is observed, in addition to being formed over the entire region, only in a part of the region. The case of being formed is also included.
In the present disclosure, the term “laminate” refers to stacking layers, two or more layers may be combined and two or more layers may be removable.
In the present disclosure, “(meth)acryloyl” means at least one of acryloyl and methacryloyl, “(meth)acrylate” means at least one of acrylate and methacrylate, and “(meth)allyl” means allyl and methallyl. Means at least one.
Further, in the present disclosure, a compound containing both a thiol group and an alkyleneoxy group is classified as a thiol compound.
Further, in the present disclosure, the polyfunctional (meth)acrylate compound having an alkyleneoxy group and an alicyclic structure is classified as a polyfunctional (meth)acrylate compound having an alkyleneoxy group.
Further, in the present disclosure, a structure in which an oxygen atom of an ester bond and a carbon atom adjacent to the oxygen atom are bonded (-O-R in -C(=O)-OR, R represents a substituent), And a structure in which an oxygen atom of a hydroxyl group is bonded to a carbon atom adjacent to the oxygen atom (OR in R of HO-R, R represents a substituent) is not classified as an alkyleneoxy group.

<Wavelength conversion member>
The wavelength conversion member of the present disclosure has a cured product obtained by curing a curable composition containing at least a quantum dot phosphor and a polyfunctional thiol compound, and the thiol group reaction rate of the cured product is 15%. ~65%.
The wavelength conversion member of the present disclosure may include other components such as a coating material described below, if necessary.
The wavelength conversion member of the present disclosure is suitably used for image display.

The wavelength conversion member of the present disclosure has a reaction rate of thiol groups of a cured product of 15% to 65%. By setting the reaction rate of the thiol group of the cured product within a specific range, the wavelength conversion member is excellent in light resistance and wet heat resistance in a high temperature environment. The reason for this is presumed as follows. First, when the reaction rate of the thiol group of the cured product is 65% or less, the thiol group that is not used in the curing reaction of the curable composition is easily coordinated with the quantum dot phosphor. As a result, the quantum dot phosphor is protected by the unreacted thiol group, the oxidative deterioration of the quantum dot phosphor is suppressed, and the light resistance and wet heat resistance of the wavelength conversion member in a high temperature environment are improved. In addition, when the reaction rate of the thiol group of the cured product is 15% or more, the amount of unreacted thiol groups becomes too large, so that a cured product cannot be suitably prepared, and the strength of the cured product becomes insufficient. Can be suppressed.

The reaction rate of the thiol group of the cured product is calculated by performing FT-IR (Fourier transform infrared spectrophotometer) measurement on the curable composition and the cured product, as described below. First, the surface of the curable composition to be measured and the surface of the wavelength conversion member are analyzed by ATR (Attenuated Total Reflection Method) using FT-IR Spectrometer (Perkin Elmer). The background measurement is performed with air, and FT-IR measurement is performed under the condition that the number of times of integration is 16 times. When the wavelength conversion member has a coating material, the cured product of the wavelength conversion member with the coating material peeled off is subjected to FT-IR measurement.
By the above-mentioned FT-IR measurement, the following peak areas of V1 to V3 are obtained for the curable composition, and the following peak areas of V4 to V6 are obtained for the cured product.
V1: peak attributed to S-H stretching vibration (peak wavelength: 2569cm ^-1) peak area of V2: peak attributed to C-H stretching vibration (peak wavelength: 2957cm ^-1) peak area of V3: C = C Peak area attributable to C stretching vibration (peak wavelength: 1637 cm ^-1 ) V4: Peak area attributable to S-H stretching vibration (peak wavelength: 2569 cm ^-1 ) V5: C-H stretching vibration attribution is the peak (peak wavelength: 2957cm ^-1) of the peak area V6: C = peak attributed to C stretching vibration (peak wavelength: 1637 cm ^-1) and the peak area of the curable composition and the cured product, the following Of the FT-IR peak area ratio of the FT-IR peak area ratio, and based on these FT-IR peak area ratio values A to D, the reaction rate of the thiol group and, if necessary, the reaction rate of the carbon-carbon double bond are calculated from the following formulas. ..
FT-IR peak area ratio: V1/V2=A
FT-IR peak area ratio: V3/V2=B
FT-IR peak area ratio: V4/V5=C
FT-IR peak area ratio: V6/V5=D
Reaction rate of thiol group: 100-100 x (C/A)
Reaction rate of carbon-carbon double bond: 100-100 x (D/B)

In the wavelength conversion member of the present disclosure, the reaction rate of the thiol group of the cured product is 20% to 65% from the viewpoint of suitably suppressing the oxidative deterioration of the quantum dot phosphor and obtaining the cured product more suitably. Is more preferable, 25% to 63% is more preferable, 28% to 60% is further preferable, and 28% to 50% is particularly preferable.

In the wavelength conversion member of the present disclosure, the cured product is preferably formed by curing a curable composition further containing a polyfunctional (meth)acrylate compound together with the quantum dot phosphor and the polyfunctional thiol compound. The reaction rate of carbon double bonds is preferably 90% or more. As a result, when the curable composition cures, the enethiol reaction proceeds between the polyfunctional thiol compound and the polyfunctional (meth)acrylate compound, and the heat resistance of the cured product tends to improve. Further, since the reaction rate of the carbon-carbon double bond of the cured product is 90% or more, the amount of the carbon-carbon double bond that has a large free volume and enhances oxygen permeability is reduced, and the oxygen permeation in the cured product is reduced. Property, and the oxidative deterioration of the quantum dot phosphor tends to be suppressed more favorably.

In the wavelength conversion member of the present disclosure, the reaction rate of the carbon-carbon double bond of the cured product is preferably 92% to 100%, and 94% to 100% from the viewpoint of further reducing oxygen permeability in the cured product. Is more preferable, and 96% to 100% is even more preferable.

The ratio (V4/V5) of the peak area (V4) attributable to the S-H stretching vibration and the peak area (V5) attributable to the C-H stretching vibration in the cured product measured by FT-IR was 0. 0.015 to 0.060, 0.020 to 0.060, or 0.025 to 0.060. When the ratio (V4/V5) is 0.015 or more, the unreacted thiol group in the cured product is favorably coordinated with the quantum dot phosphor, and oxidative deterioration of the quantum dot phosphor is favorably suppressed. It is in. When the ratio (V4/V5) is 0.060 or less, the unreacted thiol groups do not increase excessively in the cured product, and the cured product tends to have excellent strength.
When the ratio (V4/V5) is small, the glass transition temperature of the cured product tends to be high.

Further, in the wavelength conversion member of the present disclosure, the oxidative deterioration of the quantum dot phosphor is preferably suppressed, so that a good emission intensity can be obtained even when the content of the quantum dot phosphor in the cured product is smaller than that of the conventional one. It tends to be obtained.

The cured product preferably has an alkyleneoxy structure. When the cured product has an alkyleneoxy structure, it contributes to the improvement of the polarity of the cured product, and nonpolar oxygen tends to be less likely to be suitably dissolved in the components in the cured product. The alkyleneoxy structure may be derived from, for example, an alkyleneoxy group in a polyfunctional (meth)acrylate compound having an alkyleneoxy group that can be contained in the curable composition.

The cured product preferably has a sulfide structure. When the cured product has a sulfide structure, it contributes to the improvement of the polarity of the cured product, and nonpolar oxygen tends to be less likely to be suitably dissolved in the components in the cured product. The sulfide structure may be formed by a polymerization reaction between a thiol group in the polyfunctional thiol compound contained in the curable composition and a carbon-carbon double bond in the polyfunctional (meth)acrylate compound. ..

From the viewpoint of light resistance under a high temperature environment, it is preferable that the cured product has a sulfide structure bonded to two carbon atoms, and that both carbon atoms bonded to the sulfide structure are primary carbon atoms.

Further, the cured product may have an alicyclic structure. The alicyclic structure may be derived from, for example, an alicyclic structure in a polyfunctional (meth)acrylate compound having an alicyclic structure that can be contained in the curable composition.

The alicyclic structure that can be contained in the cured product is not particularly limited. Specific examples of the alicyclic structure include tricyclodecane skeleton, cyclohexane skeleton, 1,3-adamantane skeleton, hydrogenated bisphenol A skeleton, hydrogenated bisphenol F skeleton, hydrogenated bisphenol S skeleton, and isobornyl skeleton. Among these, a tricyclodecane skeleton or an isobornyl skeleton is preferable, and a tricyclodecane skeleton is more preferable.

The alicyclic structure contained in the cured product may be one type alone or at least two types.
When at least two kinds of alicyclic structures are contained in the cured product, examples of the combination of alicyclic structures include a combination of tricyclodecane skeleton and isobornyl skeleton, a combination of hydrogenated bisphenol A skeleton and isobornyl skeleton, and the like. Among these, a combination of a tricyclodecane skeleton and an isobornyl skeleton is preferable.

Further, the cured product may have an ester structure. The ester structure may be derived from the ester structure in the (meth)acryloyloxy group in the polyfunctional (meth)acrylate compound that may be contained in the curable composition.

The cured product may contain a white pigment. The details of the white pigment contained in the cured product will be described later.
The details of the quantum dot phosphor contained in the cured product are also described later.
Hereinafter, the components that may be included in the wavelength conversion member of the present disclosure and the curable composition used for producing the wavelength conversion member of the present disclosure will be described in detail.

(Quantum dot phosphor)
The quantum dot phosphor is not particularly limited, and examples thereof include particles containing at least one selected from the group consisting of II-VI group compounds, III-V group compounds, IV-VI group compounds, and IV group compounds. From the viewpoint of luminous efficiency, the quantum dot phosphor preferably contains a compound containing at least one of Cd and In.

Specific examples of the group II-VI compound, CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS , CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSe, CdHgSe, HdZgSe, CdHgSe, CdHgSe, CdHgSe, CdHgSe, CdHgSe, CdHgSe, CdHgSe, CdHgSe, and CdHgSe.
Specific examples of the III-V group compound include GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb. , AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInPSb, InInb, InInb, InInSb, InAlP, InAlP, InAlP, InAlb, InAlP, InAlP, InAlP, InAlb, InAlP, InAlb, InAlP, InAlb, InAlb.
Specific examples of the group IV-VI compounds include SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe etc. ..
Specific examples of the group IV compound include Si, Ge, SiC and SiGe.

As the quantum dot phosphor, one having a core-shell structure is preferable. By making the band gap of the compound forming the shell wider than the band gap of the compound forming the core, it becomes possible to further improve the quantum efficiency of the quantum dot phosphor. Examples of the combination of core and shell (core/shell) include CdSe/ZnS, InP/ZnS, PbSe/PbS, CdSe/CdS, CdTe/CdS, CdTe/ZnS and the like.

Further, the quantum dot phosphor may have a so-called core multi-shell structure in which the shell has a multilayer structure. To further improve the quantum efficiency of a quantum dot phosphor by stacking one or more layers having a narrow bandgap on a core having a wide bandgap, and further stacking a shell having a wide bandgap on this shell. Is possible.

The curable composition may contain one type of quantum dot phosphor alone, or may contain two or more types of quantum dot phosphor in combination. As an aspect including two or more kinds of quantum dot phosphors in combination, for example, an aspect including two or more kinds of quantum dot phosphors having different components but having the same average particle diameter, and a quantum having same components having different average particle diameters An embodiment including two or more kinds of dot phosphors and an embodiment including two or more kinds of quantum dot phosphors having different components and average particle diameters can be mentioned. The emission center wavelength of the quantum dot phosphor can be changed by changing at least one of the component of the quantum dot phosphor and the average particle diameter.

For example, the curable composition includes a quantum dot phosphor G having an emission center wavelength in the green wavelength range of 520 nm to 560 nm and a quantum dot phosphor R having an emission center wavelength in the red wavelength range of 600 nm to 680 nm. May be included. When a cured product of a curable composition containing the quantum dot phosphor G and the quantum dot phosphor R is irradiated with excitation light in the blue wavelength range of 430 nm to 480 nm, the quantum dot phosphor G and the quantum dot phosphor R. Emits green light and red light, respectively. As a result, white light can be obtained by the green light and the red light emitted from the quantum dot phosphor G and the quantum dot phosphor R, and the blue light that passes through the cured product.

The quantum dot phosphor may be used in the state of a quantum dot phosphor dispersion liquid dispersed in a dispersion medium. Examples of the dispersion medium in which the quantum dot phosphor is dispersed include water, various organic solvents, and monofunctional (meth)acrylate compounds.
Examples of the organic solvent usable as the dispersion medium include acetone, ethyl acetate, toluene, n-hexane and the like.
The monofunctional (meth)acrylate compound that can be used as the dispersion medium is not particularly limited as long as it is a liquid at room temperature (25° C.), and isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate and the like can be used. Can be mentioned.
Among these, the dispersion medium is preferably a monofunctional (meth)acrylate compound from the viewpoint of eliminating the step of volatilizing the dispersion medium when curing the curable composition, and has a cycloaliphatic structure. A monofunctional (meth)acrylate compound is more preferable, at least one of isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate is further preferable, and isobornyl (meth)acrylate is particularly preferable.

When a monofunctional (meth)acrylate compound is used as the dispersion medium and the curable composition contains a polyfunctional (meth)acrylate compound, the monofunctional (meth)acrylate compound and the polyfunctional (meth)acrylate compound in the curable composition The mass-based content ratio (monofunctional (meth)acrylate compound/polyfunctional (meth)acrylate compound) is preferably 0.01 to 0.30, and more preferably 0.02 to 0.20. More preferably, it is more preferably 0.05 to 0.20.

The mass-based proportion of the quantum dot phosphor in the quantum dot phosphor dispersion liquid is preferably 1% by mass to 15% by mass, more preferably 1% by mass to 14% by mass, and 2% by mass to It is more preferably 12% by mass.

The content of the quantum dot phosphor dispersion liquid in the curable composition is a curable composition when the mass-based ratio of the quantum dot phosphor in the quantum dot phosphor dispersion liquid is 1% by mass to 15% by mass. Is preferably 0.5% by mass to 9% by mass, more preferably 0.8% by mass to 8% by mass, and further preferably 1% by mass to 7% by mass. More preferable. The content of the quantum dot phosphor in the curable composition is preferably 0.05% by mass to 1.0% by mass, and preferably 0.08% by mass, with respect to the total amount of the curable composition. % To 0.8 mass% is more preferable, and 0.1 mass% to 0.7 mass% is further preferable. When the content of the quantum dot phosphor is 0.05% by mass or more, a sufficient emission intensity tends to be obtained when the cured product is irradiated with excitation light, and the content of the quantum dot phosphor is 1.0. When it is at most% by mass, aggregation of the quantum dot phosphor tends to be suppressed.

(Polyfunctional thiol compound)
The curable composition contains a polyfunctional thiol compound. When the curable composition contains a polyfunctional thiol compound and a polyfunctional (meth)acrylate compound described below, when the curable composition cures, the polyfunctional thiol compound and the polyfunctional (meth)acrylate compound are The enethiol reaction proceeds, and the heat resistance of the cured product tends to improve. Moreover, when the curable composition contains a polyfunctional thiol compound, the optical properties of the cured product tend to be further improved. The polyfunctional thiol compound may be a compound having two or more thiol groups in one molecule, and is preferably a compound having three or four thiol groups in one molecule.

From the viewpoint of light resistance under a high temperature environment, the polyfunctional thiol compound preferably has at least one thiol group to which a primary carbon atom is bonded.

The curable composition is a thiol compound having at least one thiol group bonded with a primary carbon atom, and a thiol compound having at least one thiol group bonded with a secondary carbon atom or a tertiary carbon atom. Both may be included.

Specific examples of the polyfunctional thiol compound include ethylene glycol bis(3-mercaptopropionate), diethylene glycol bis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), 1,2- Propylene glycol bis(3-mercaptopropionate), diethylene glycol bis(3-mercaptobutyrate), 1,4-butanediol bis(3-mercaptopropionate), 1,4-butanediol bis(3-mercaptobutyrate) Rate), 1,8-octanediol bis(3-mercaptopropionate), 1,8-octanediol bis(3-mercaptobutyrate), hexanediol bisthioglycolate, trimethylolpropane tris(3-mercaptopropionate) Pionate), trimethylolpropane tris(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptoisobutyrate), trimethylolpropane tris(2-mercaptoisobutyrate), trimethylolpropane tristhioglycolate, Tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, trimethylolethane tris(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate). ), pentaerythritol tetrakis (3-mercaptoisobutyrate), pentaerythritol tetrakis (2-mercaptoisobutyrate), dipentaerythritol hexakis (3-mercaptopropionate), dipentaerythritol hexakis (2-mercaptopropoxide) Pionate), dipentaerythritol hexakis (3-mercaptobutyrate), dipentaerythritol hexakis (3-mercaptoisobutyrate), dipentaerythritol hexakis (2-mercaptoisobutyrate), pentaerythritol tetrakisthioglyco Rate, dipentaerythritol hexakisthioglycolate and the like.

The curable composition may contain a monofunctional thiol compound having one thiol group in one molecule.

Specific examples of the monofunctional thiol compound, hexanethiol, 1-heptanethiol, 1-octanethiol, 1-nonanethiol, 1-decanethiol, 3-mercaptopropionic acid, methyl mercaptopropionate, methoxybutyl mercaptopropionate, Examples include octyl mercaptopropionate, tridecyl mercaptopropionate, 2-ethylhexyl-3-mercaptopropionate, and n-octyl-3-mercaptopropionate.

The content of the thiol compound in the curable composition (the total of the polyfunctional thiol compound and the monofunctional thiol compound used as necessary, preferably the polyfunctional thiol compound) is, for example, 20 mass% to 65 mass% is preferable, 25 mass% to 63 mass% is more preferable, and 30 mass% to 60 mass% is further preferable. When the content of the thiol compound is 20% by mass or more, the reaction rate of the thiol group tends to be reduced, and when the content of the thiol compound is 65% by mass or less, the unreacted thiol group is It tends to be possible to suppress too many.

When a monofunctional thiol compound is used, the content of the thiol compound in the curable composition may be, for example, 1% by mass to 20% by mass with respect to the total amount of the curable composition.

Thiol group in thiol compound (total of polyfunctional thiol compound and monofunctional thiol compound optionally used, preferably polyfunctional thiol compound) based on total number of carbon-carbon double bonds in polyfunctional (meth)acrylate compound The ratio of the total number (total number of thiol groups/total number of carbon-carbon double bonds) is preferably 0.5 to 5.0, more preferably 0.8 to 4.0, It is more preferably 1.0 to 3.5, and particularly preferably 1.2 to 3.0.

(Polyfunctional (meth)acrylate compound)
The curable composition may contain a polyfunctional (meth)acrylate compound. The polyfunctional (meth)acrylate compound may be a compound having two or more (meth)acryloyl groups in one molecule. The polyfunctional (meth)acrylate compound is preferably a compound having 2 to 5 (meth)acryloyl groups in one molecule, and preferably two in one molecule, from the viewpoint of heat and humidity resistance under a high temperature environment. It is more preferably a compound having 4 to 4 (meth)acryloyl groups, and even more preferably a compound having 2 or 3 (meth)acryloyl groups in one molecule.

Specific examples of the polyfunctional (meth)acrylate compound include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate. Alkylene glycol di(meth)acrylate; polyalkylene glycol di(meth)acrylate such as polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate; trimethylolpropane tri(meth)acrylate, ethylene oxide-added trimethylolpropane tri( (Meth)acrylate, tri(meth)acrylate compounds such as tris(2-acryloyloxyethyl)isocyanurate; ethylene oxide-added pentaerythritol tetra(meth)acrylate, trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc. Tetra(meth)acrylate compound; tricyclodecane dimethanol di(meth)acrylate, cyclohexane dimethanol di(meth)acrylate, 1,3-adamantane dimethanol di(meth)acrylate, hydrogenated bisphenol A (poly)ethoxydi( (Meth)acrylate, hydrogenated bisphenol A (poly)propoxydi(meth)acrylate, hydrogenated bisphenol F(poly)ethoxydi(meth)acrylate, hydrogenated bisphenol F(poly)propoxydi(meth)acrylate, hydrogenated bisphenol S(poly) Examples thereof include (meth)acrylate compounds having an alicyclic structure such as ethoxydi(meth)acrylate and hydrogenated bisphenol S(poly)propoxydi(meth)acrylate.

The polyfunctional (meth)acrylate compound may have an alkyleneoxy group, or may be a bifunctional (meth)acrylate compound having an alkyleneoxy group.

As the alkyleneoxy group, for example, an alkyleneoxy group having 2 to 4 carbon atoms is preferable, an alkyleneoxy group having 2 or 3 carbon atoms is more preferable, and an alkyleneoxy group having 2 carbon atoms is further preferable.
The alkyleneoxy group contained in the polyfunctional (meth)acrylate compound may be one type or two or more types.

The polyfunctional (meth)acrylate compound having an alkyleneoxy group may be a polyfunctional (meth)acrylate compound having a polyalkyleneoxy group containing a plurality of alkyleneoxy groups.

When the polyfunctional (meth)acrylate compound has an alkyleneoxy group, the number of alkyleneoxy groups in one molecule is preferably 2 to 30, and more preferably 2 to 20. The number is more preferably 10 to 10, and most preferably 3 to 5.

When the polyfunctional (meth)acrylate compound has an alkyleneoxy group, it preferably has a bisphenol structure. This tends to improve the heat resistance of the cured product. Examples of the bisphenol structure include a bisphenol A structure and a bisphenol F structure, and among them, the bisphenol A structure is preferable.

Specific examples of the polyfunctional (meth)acrylate compound having an alkyleneoxy group include alkoxyalkyl (meth)acrylates such as butoxyethyl (meth)acrylate; diethylene glycol monoethyl ether (meth)acrylate, triethylene glycol monobutyl ether (meth). Acrylate, tetraethylene glycol monomethyl ether (meth)acrylate, hexaethylene glycol monomethyl ether (meth)acrylate, octaethylene glycol monomethyl ether (meth)acrylate, nonaethylene glycol monomethyl ether (meth)acrylate, dipropylene glycol monomethyl ether (meth) Polyalkylene glycol monoalkyl ether (meth)acrylate such as acrylate, heptapropylene glycol monomethyl ether (meth)acrylate, tetraethylene glycol monoethyl ether (meth)acrylate; polyalkylene glycol such as hexaethylene glycol monophenyl ether (meth)acrylate Monoaryl ether (meth)acrylate; (meth)acrylate compound having a heterocycle such as tetrahydrofurfuryl (meth)acrylate; triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, hexaethylene glycol mono( (Meth)acrylate compounds having a hydroxyl group such as (meth)acrylate and octapropylene glycol mono(meth)acrylate; (meth)acrylate compounds having a glycidyl group such as glycidyl (meth)acrylate; polyethylene glycol di(meth)acrylate, polypropylene glycol Polyalkylene glycol di(meth)acrylate such as di(meth)acrylate; Tri(meth)acrylate compound such as ethylene oxide-added trimethylolpropane tri(meth)acrylate; Tetra(meth) such as ethylene oxide-added pentaerythritol tetra(meth)acrylate Acrylate compounds; bisphenol di(meth)acrylate compounds such as ethoxylated bisphenol A type di(meth)acrylate, propoxylated bisphenol A type di(meth)acrylate, propoxylated ethoxylated bisphenol A type di(meth)acrylate; Can be mentioned.
Examples of the polyfunctional (meth)acrylate compound having an alkyleneoxy group include ethoxylated bisphenol A type di(meth)acrylate, propoxylated bisphenol A type di(meth)acrylate and propoxylated ethoxylated bisphenol A type di(meth)acrylate. Acrylate is preferable, and ethoxylated bisphenol A type di(meth)acrylate is more preferable.

When the curable composition contains a polyfunctional (meth)acrylate compound, the content of the polyfunctional (meth)acrylate compound in the curable composition is, for example, 30% by mass to the total amount of the curable composition. It is preferably 75% by mass, more preferably 32% by mass to 70% by mass, and further preferably 35% by mass to 60% by mass. When the content of the polyfunctional (meth)acrylate compound is 30% by mass or more, a decrease in the reaction rate of carbon-carbon double bonds tends to be suppressed, and the content of the polyfunctional (meth)acrylate compound is 75% by mass. When it is below, there is a tendency that it is possible to prevent the reaction rate of the thiol group from becoming too high.

The mass-based proportion of the polyfunctional (meth)acrylate compound having an alkyleneoxy group in the polyfunctional (meth)acrylate compound is preferably 30% by mass to 100% by mass, and 32% by mass to 80% by mass. It is more preferable that the content is 33% by mass to 70% by mass.

(Photopolymerization initiator)
The curable composition may include a photopolymerization initiator. The photopolymerization initiator is not particularly limited, and specific examples thereof include compounds that generate radicals upon irradiation with active energy rays such as ultraviolet rays.

Specific examples of the photopolymerization initiator include benzophenone, N,N′-tetraalkyl-4,4′-diaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1,4,4'-bis(dimethylamino)benzophenone (also called "Michler's ketone"), 4,4'-bis (Diethylamino)benzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 1-hydroxycyclohexylphenyl ketone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4- Aromatic ketone compounds such as (2-hydroxyethoxy)-phenyl)-2-hydroxy-2-methyl-1-propan-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; alkyl Quinone compounds such as anthraquinone and phenanthrenequinone; benzoin compounds such as benzoin and alkylbenzoin; benzoin ether compounds such as benzoin alkyl ether and benzoin phenyl ether; benzyl derivatives such as benzyl dimethyl ketal; 2-(o-chlorophenyl)-4,5 -Diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, 2-(2,4-dimethoxyphenyl)- 2,4,5-triarylimidazole dimers such as 4,5-diphenylimidazole dimers; acridine derivatives such as 9-phenylacridine and 1,7-(9,9'-acridinyl)heptane; -Octanedione 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1- Oxime ester compounds such as (O-acetyloxime); coumarin compounds such as 7-diethylamino-4-methylcoumarin; thioxanthone compounds such as 2,4-diethylthioxanthone; 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide; 2,4,6-trimethylbenzoyl- Acylphosphine oxide compounds such as phenyl-ethoxy-phosphine oxide; and the like. The curable composition may contain one type of photopolymerization initiator alone, or may contain two or more types of photopolymerization initiators in combination.

From the viewpoint of curability, the photopolymerization initiator is preferably at least one selected from the group consisting of an acylphosphine oxide compound, an aromatic ketone compound, and an oxime ester compound. From the acylphosphine oxide compound and the aromatic ketone compound, At least one selected from the group consisting of is more preferable, and an acylphosphine oxide compound is further preferable.

The content of the photopolymerization initiator in the curable composition is, for example, preferably 0.1% by mass to 5% by mass, and 0.1% by mass to 3% by mass with respect to the total amount of the curable composition. %, more preferably 0.3% by mass to 1.5% by mass. If the content of the photopolymerization initiator is 0.1% by mass or more, the sensitivity of the curable composition tends to be sufficient, and if the content of the photopolymerization initiator is 5% by mass or less, The influence on the hue of the curable composition and the decrease in storage stability tend to be suppressed.

(Liquid medium)
The curable composition may include a liquid medium. The liquid medium means a medium in a liquid state at room temperature (25° C.).

Specific examples of the liquid medium include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isopropyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, methyl-n-pentyl ketone, methyl-n-hexyl ketone, diethyl ketone, Ketone solvents such as dipropyl ketone, diisobutyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone; diethyl ether, methyl ethyl ether, methyl-n-propyl ether, diisopropyl Ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, Diethylene glycol methyl-n-propyl ether, diethylene glycol methyl-n-butyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, diethylene glycol methyl-n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, tri Ethylene glycol methyl ethyl ether, triethylene glycol methyl-n-butyl ether, triethylene glycol di-n-butyl ether, triethylene glycol methyl-n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl Ether, tetraethylene glycol methyl-n-butyl ether, tetraethylene glycol di-n-butyl ether, tetraethylene glycol methyl-n-hexyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol Di-n-butyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol methyl-n-butyl ether, dipropylene Glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol methyl ethyl ether, tripropylene glycol methyl -N-butyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol methyl-n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetrapropylene glycol methyl ethyl ether, tetrapropylene glycol methyl-n-butyl ether , Tetrapropylene glycol di-n-butyl ether, tetrapropylene glycol methyl-n-hexyl ether and other ether solvents; propylene carbonate, ethylene carbonate, diethyl carbonate and other carbonate solvents; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate , N-butyl acetate, isobutyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 2-(2- Butoxyethoxy) ethyl, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, dipropylene glycol ethyl ether acetate , Glycol diacetate, methoxytriethylene glycol acetate, ethyl propionate, n-butyl propionate, isoamyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-lactate Amyl, ethylene glycol methyl ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, γ -Ester solvents such as butyrolactone and γ-valerolactone; acetonitrile, N-meth Aprotic polarities such as tylpyrrolidinone, N-ethylpyrrolidinone, N-propylpyrrolidinone, N-butylpyrrolidinone, N-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide and the like. Solvent: methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, n-pentanol, isopentanol, 2-methylbutanol, sec-pentanol, t-pentanol , 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonyl alcohol, n-decanol , Sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, cyclohexanol, methylcyclohexanol, benzyl alcohol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, Alcohol solvent such as diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether , Diethylene glycol mono-n-hexyl ether, triethylene glycol monoethyl ether, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, etc. Glycol monoether solvent; terpene, terpineol, myrcene, alloocimene, limonene, terpene solvent such as dipentene, pinene, carvone, ocimene, ferrandrene; straight silicone oil such as dimethyl silicone oil, methylphenyl silicone oil, methylhydrogen silicone oil; Amino-modified silicone oil, epoxy-modified silicone oil, carbo Xy-modified silicone oil, carbinol-modified silicone oil, mercapto-modified silicone oil, different functional group-modified silicone oil, polyether-modified silicone oil, methylstyryl-modified silicone oil, hydrophilic special modified silicone oil, higher alkoxy-modified silicone oil, higher fatty acid Modified silicone oil such as modified silicone oil and fluorine-modified silicone oil; butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, Hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, eicosenoic acid, etc., saturated aliphatic monocarboxylic acids having 4 or more carbon atoms; oleic acid, elaidic acid, linoleic acid, palmitoleic acid, etc., having 8 or more carbon atoms Saturated aliphatic monocarboxylic acid; and the like. When the curable composition contains a liquid medium, it may contain one type of liquid medium alone, or may contain two or more types of liquid medium in combination.

When the curable composition contains a liquid medium, the content ratio of the liquid medium in the curable composition is preferably, for example, 1% by mass to 10% by mass based on the total amount of the curable composition. The content is more preferably 10% by mass to 10% by mass, and further preferably 4% by mass to 7% by mass.

(Carboxylic acid having 1 to 17 carbon atoms)
The curable composition may contain a carboxylic acid having 1 to 17 carbon atoms (hereinafter, also referred to as “specific carboxylic acid”). The specific carboxylic acid is a carboxylic acid having 2 to 12 carbon atoms from the viewpoint of being less likely to cause stains on the surface of the cured product, having excellent reliability of the cured product, and having less steric hindrance and being easily coordinated with the quantum dot phosphor. Is preferable, a carboxylic acid having 2 to 10 carbon atoms is more preferable, a carboxylic acid having 3 to 8 carbon atoms is further preferable, a carboxylic acid having 3 to 6 carbon atoms is particularly preferable, and a carboxylic acid having 3 to 5 carbon atoms is preferable. Acids are even more preferred.
The carbon of the carboxy group is included in the carbon number of the specific carboxylic acid.

The specific carboxylic acid may be an unsaturated carboxylic acid or a saturated carboxylic acid. For example, by reacting the carbon-carbon double bond in the unsaturated carboxylic acid with the thiol group in the polyfunctional thiol compound, the specific carboxylic acid becomes difficult to stain on the surface of the cured product, and from the viewpoint of excellent reliability of the cured product. , Unsaturated carboxylic acids are preferable, and methacrylic acid, acrylic acid, and the like are more preferable.

The specific carboxylic acid may be a carboxylic acid having one or more carboxy groups or a carboxylic acid having two or more carboxy groups.

The specific carboxylic acid may have a substituent. Specific examples of the substituent include a thiol group, amino group, hydroxy group, alkoxy group, acyl group, sulfonic acid group, aryl group, halogen atom, methacryl group and acryl group. The carbon number in the specific carboxylic acid does not include the carbon in the substituent.

As the specific carboxylic acid, specifically, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, 2-ethylbutyric acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, Lauric acid, mistyric acid, palmitic acid, margaric acid, methacrylic acid, acrylic acid, fumaric acid, maleic acid, mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid, mercaptovaleric acid, lactic acid, malic acid, citric acid, benzoic acid, phenyl Examples thereof include acetic acid, phenylpropionic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid and ε-aminocaproic acid. Among them, the specific carboxylic acid preferably contains at least one selected from the group consisting of acetic acid, mercaptopropionic acid and methacrylic acid.
As the specific carboxylic acid, one type may be used alone, or two or more types may be used in combination.

When the curable composition contains a specific carboxylic acid, the content ratio of the specific carboxylic acid to the quantum dot phosphor on a mass basis (specific carboxylic acid/quantum dot phosphor) depends on the reliability of the cured product and the quantum dot fluorescence. From the viewpoint of coordination with the body, it is preferably 0.06 to 6.2, more preferably 0.08 to 5.5, and further preferably 0.09 to 5.3. ..

The curable composition may or may not contain a carboxylic acid having 18 or more carbon atoms such as oleic acid.

(White pigment)
The curable composition may include a white pigment.
Specific examples of the white pigment include titanium oxide, barium sulfate, zinc oxide, calcium carbonate and the like. Among these, titanium oxide is preferable from the viewpoint of light scattering efficiency.
When the curable composition contains titanium oxide as a white pigment, the titanium oxide may be rutile type titanium oxide or anatase type titanium oxide, and preferably rutile type titanium oxide.

The average particle size of the white pigment is preferably 0.1 μm to 1 μm, more preferably 0.2 μm to 0.8 μm, and further preferably 0.2 μm to 0.5 μm.
In the present disclosure, the average particle size of the white pigment can be measured as follows.
The white pigment extracted from the curable composition is dispersed in purified water containing a surfactant to obtain a dispersion liquid. In the volume-based particle size distribution measured with a laser diffraction particle size distribution analyzer (for example, Shimadzu Corporation, SALD-3000J) using this dispersion, the value when the cumulative value from the small diameter side is 50% ( Let the median diameter (D50) be the average particle diameter of the white pigment. A method for extracting the white pigment from the curable composition can be obtained, for example, by diluting the curable composition with a liquid medium, precipitating the white pigment by centrifugation or the like, and collecting the white pigment.
The average particle size of the white pigment contained in the cured product was calculated by observing the particles using a scanning electron microscope to calculate the equivalent circle diameter (geometric mean of major axis and minor axis) of 50 particles, It can be calculated as an arithmetic mean value.

When the curable composition contains a white pigment, from the viewpoint of suppressing aggregation of the white pigment in the curable composition, the white particles preferably have an organic material layer containing an organic material on at least a part of the surface. Examples of the organic material contained in the organic material layer include organic silane, organosiloxane, fluorosilane, organic phosphonate, organic phosphoric acid compound, organic phosphinate, organic sulfonic acid compound, carboxylic acid, carboxylic acid ester, carboxylic acid derivative, amide, and hydrocarbon. Examples thereof include waxes, polyolefins, polyolefin copolymers, polyols, polyol derivatives, alkanolamines, alkanolamine derivatives, and organic dispersants.
The organic material contained in the organic material layer preferably contains a polyol, an organic silane, or the like, and more preferably contains at least one of the polyol and the organic silane.
Specific examples of the organic silane include octyltriethoxysilane, nonyltriethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, tridecyltriethoxysilane, tetradecyltriethoxysilane, pentadecyltriethoxysilane, and hexadecyltriethoxysilane. Examples thereof include silane, heptadecyltriethoxysilane and octadecyltriethoxysilane.
Specific examples of the organosiloxane include polydimethylsiloxane (PDMS) terminated with a trimethylsilyl functional group (PDMS), polymethylhydrosiloxane (PMHS), and polysiloxane derived from functionalization of PMHS with olefin (by hydrosilylation). To be
Specific examples of the organic phosphonate include n-octylphosphonic acid and its ester, n-decylphosphonic acid and its ester, 2-ethylhexylphosphonic acid and its ester, and camphyl phosphonic acid and its ester.
Specific examples of the organic phosphoric acid compound include organic acid phosphates, organic pyrophosphates, organic polyphosphates, organic metaphosphates and salts thereof.
Specific examples of the organic phosphinate include, for example, n-hexylphosphinic acid and its ester, n-octylphosphinic acid and its ester, di-n-hexylphosphinic acid and its ester, and di-n-octylphosphinic acid and its ester. Can be mentioned.
Specific examples of the organic sulfonic acid compound include alkyl sulfonic acids such as hexyl sulfonic acid, octyl sulfonic acid and 2-ethylhexyl sulfonic acid, these alkyl sulfonic acids, and metal ions such as sodium, calcium, magnesium, aluminum and titanium, ammonium. Examples thereof include salts with ions and organic ammonium ions such as triethanolamine.
Specific examples of the carboxylic acid include maleic acid, malonic acid, fumaric acid, benzoic acid, phthalic acid, stearic acid, oleic acid and linoleic acid.
Specific examples of the carboxylic acid ester include the above-mentioned carboxylic acid, ethylene glycol, propylene glycol, trimethylolpropane, diethanolamine, triethanolamine, glycerol, hexanetriol, erythritol, mannitol, sorbitol, pentaerythritol, bisphenol A, hydroquinone and fluoro. Examples thereof include esters and partial esters formed by reaction with a hydroxy compound such as roglucinol.
Specific examples of the amide include stearic acid amide, oleic acid amide, and erucic acid amide.
Specific examples of polyolefins and copolymers thereof include copolymers of polyethylene, polypropylene, ethylene and one or more compounds selected from propylene, butylene, vinyl acetate, acrylate, acrylamide and the like.
Specific examples of the polyol include glycerol, trimethylolethane, trimethylolpropane and the like.
Specific examples of the alkanolamine include diethanolamine and triethanolamine.
Specific examples of the organic dispersant include a polymeric organic dispersant having a functional group such as citric acid, polyacrylic acid, polymethacrylic acid, anionic, cationic, zwitterionic or nonionic.
When the aggregation of the white pigment in the curable composition is suppressed, the dispersibility of the white pigment in the cured product tends to improve.

The white pigment may have a metal oxide layer containing a metal oxide on at least a part of the surface. Examples of the metal oxide contained in the metal oxide layer include silicon dioxide, aluminum oxide, zirconia, phosphoria, and boria. The metal oxide layer may be a single layer or two or more layers. When the white pigment has two metal oxide layers, it preferably includes a first metal oxide layer containing silicon dioxide and a second metal oxide layer containing aluminum oxide.
The white pigment having the metal oxide layer tends to improve the dispersibility of the white pigment in the cured product.

The white pigment may have an organic material layer and a metal oxide layer. In this case, it is preferable that the metal oxide layer and the organic material layer are provided on the surface of the white pigment in the order of the metal oxide layer and the organic material layer. When the white pigment has an organic material layer and two metal oxide layers, on the surface of the white pigment, a first metal oxide layer containing silicon dioxide, a second metal oxide layer containing aluminum oxide, and an organic material. The layers are preferably provided in the order of the first metal oxide layer, the second metal oxide layer, and the organic material layer.

When the curable composition contains a white pigment, the content of the white pigment in the curable composition is, for example, 0.05% by mass to 1.0% by mass with respect to the total amount of the curable composition. Is preferable, 0.1 mass% to 1.0 mass% is more preferable, and 0.2 mass% to 0.5 mass% is further preferable.

(Other ingredients)
The curable composition may further contain other components such as a polymerization inhibitor, a silane coupling agent, a surfactant, an adhesion promoter and an antioxidant. The curable composition may include one type alone or two or more types in combination for each of the other components.
Moreover, the curable composition may contain the (meth)allyl compound as needed.

(Method for preparing curable composition)
The curable composition may be prepared, for example, by mixing the quantum dot phosphor, the polyfunctional thiol compound, the polyfunctional (meth)acrylate compound, the photopolymerization initiator and, if necessary, the above-mentioned components by a conventional method. it can. The quantum dot phosphor is preferably mixed in a dispersion medium in a dispersed state.

The shape of the wavelength conversion member is not particularly limited, and examples thereof include a film shape and a lens shape. When the wavelength conversion member is applied to the backlight unit described later, the wavelength conversion member is preferably in the form of a film.

When the cured product is in the form of a film, the average thickness of the cured product is, for example, preferably 50 μm to 200 μm, more preferably 50 μm to 150 μm, and further preferably 80 μm to 120 μm. When the average thickness is 50 μm or more, the wavelength conversion efficiency tends to be further improved, and when the average thickness is 200 μm or less, the backlight unit tends to be thinner when applied to a backlight unit described later. is there.
The average thickness of the film-shaped cured product is, for example, an arithmetic average value of the thicknesses at three arbitrary points measured by observing the cross section of the cured product using a micrometer or using an SEM (scanning electron microscope). Desired.
When obtaining the average thickness of a cured product from a film-shaped and multi-layer wavelength conversion member, the average thickness of the wavelength conversion member and the average thickness of the wavelength conversion member other than the cured product (for example, the average thickness of the coating material) are measured with a micrometer. Alternatively, the average thickness of the wavelength conversion member other than the cured product may be subtracted from the average thickness of the wavelength conversion member.
When the average thickness of the cured product is obtained from a film-shaped and multi-layered wavelength conversion member, the average thickness of the cured product is measured by using a reflection spectroscopic film thickness meter or by using an SEM (scanning electron microscope). The cross section is observed, and the thickness is calculated as an arithmetic average value of the thicknesses at three arbitrary positions.

The wavelength conversion member may be one obtained by curing one type of curable composition, or may be obtained by curing two or more types of curable compositions. For example, when the wavelength conversion member is a film, the wavelength conversion member emits the first cured product obtained by curing the curable composition containing the first quantum dot phosphor and the first quantum dot phosphor. It may be laminated with a second cured product obtained by curing a curable composition containing a second quantum dot phosphor having different characteristics.

The wavelength conversion member can be obtained by forming a coating film of a curable composition, a molded product, etc., performing a drying treatment if necessary, and then irradiating with active energy rays such as ultraviolet rays. The wavelength of the active energy ray and the irradiation amount can be appropriately set according to the composition of the curable composition. In one aspect, it is irradiated with ultraviolet rays having a wavelength of 280nm~400nm at dose of ^{100mJ / cm 2 ~5000mJ / cm 2} . Examples of the ultraviolet ray source include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a black light lamp, and a microwave-excited mercury lamp.

Further, the cured product preferably has a glass transition temperature (Tg) of 47° C. or lower, more preferably 0° C. to 47° C., and more preferably 10° C. to 47, from the viewpoint of further improving adhesion and processability. C. is more preferable, and 15 to 21.degree. C. is particularly preferable. The glass transition temperature (Tg) of the cured product can be measured using a dynamic viscoelasticity measuring device (for example, Rheometric Scientific Co., Solid Analyzer RSA-III) at a frequency of 10 Hz.

From the viewpoint of improving adhesion and heat resistance, the cured product preferably has a storage elastic modulus of 1×10 ³ Pa to 1×10 ¹⁰ Pa measured under the conditions of a frequency of 10 Hz and a temperature of 25° C., and 1 It is more preferably x10 ⁴ Pa to 1x10 ⁹ Pa, further preferably 1x10 ⁵ Pa to 1x10 ⁷ Pa. The storage elastic modulus of a cured product can be measured using a dynamic viscoelasticity measuring device (for example, Rheometric Scientific Co., Solid Analyzer RSA-III).

The moisture permeability of the cured product under the conditions of a temperature of 40° C. and a relative humidity of 70% is preferably 20 g/(m ² ·day) or more, and more preferably 40 g/(m ² ·day) or more. , 60 g/(m ² ·day) or more is more preferable, 80 g/(m ² ·day) or more is particularly preferable, and 100 g/(m ² ·day) or more is even more preferable. When the moisture permeability of the cured product is equal to or higher than a certain value, the cured product has high polarity and nonpolar oxygen is less likely to dissolve in a component (for example, a resin component) in the cured product. Therefore, it is presumed that the oxidative deterioration of the quantum dot phosphor in the cured product is suitably suppressed. Further, a cured product having a moisture permeability of a certain value or more easily adsorbs moisture, and the adsorbed moisture increases the polarity of the cured product, and nonpolar oxygen is a component (for example, resin component) in the cured product. It is presumed that oxidative deterioration of the quantum dot phosphor is preferably suppressed because it becomes difficult to dissolve due to ).

Further, the water vapor transmission rate is preferably 300 g/(m ² ·day) or less, and 250 g/(m ² ·day) or less, from the viewpoint of maintaining the shape of the cured product and the strength of the cured product. It is more preferably 230 g/(m ² ·day) or less, still more preferably 210 g/(m ² ·day) or less.

The moisture permeability of the cured product may be measured according to the measuring method of JIS Z 0208:1976. Specifically, measure 10 g of calcium chloride in a moisture permeable cup, fix each cured product in a moisture permeable cup so that the exposed portion has a diameter of 6 cm, and under the conditions of 40° C. and 70% relative humidity. The moisture vapor transmission rate is calculated from the change in mass of the cured product when left standing for 24 hours.

The wavelength conversion member of the present disclosure may further include a coating material that covers at least a part of the cured product. For example, when the cured product is in the form of a film, one or both sides of the cured product in the form of a film may be covered with a coating material in the form of a film.

It is preferable that the coating material has a barrier property against oxygen from the viewpoint of suppressing a decrease in luminous efficiency of the quantum dot phosphor.

When the wavelength conversion member has a coating material, the material of the coating material is not particularly limited. For example, a resin can be used. The type of resin is not particularly limited, and polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyolefins such as polyethylene (PE) and polypropylene (PP); polyamides such as nylon; ethylene-vinyl alcohol copolymers. (EVOH) and the like. Further, the covering material may be one having a barrier layer for enhancing the barrier function (barrier film). Examples of the barrier layer include an inorganic layer containing an inorganic substance such as alumina and silica.

The coating material may have a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, a combination of two or more layers made of different materials may be used.

When the coating material is in the form of a film, the average thickness of the coating material is, for example, preferably 80 μm to 150 μm, more preferably 100 μm to 140 μm, and further preferably 100 μm to 135 μm. When the average thickness is 80 μm or more, functions such as barrier properties tend to be sufficient, and when the average thickness is 150 μm or less, decrease in light transmittance tends to be suppressed.
The average thickness of the film-shaped covering material is determined in the same manner as the average thickness of the film-shaped wavelength conversion member.

From the viewpoint of cost reduction while maintaining the reliability of the wavelength conversion member, the coating material preferably contains EVOH. The coating material containing EVOH tends to be inferior in water barrier property to a barrier film composed of a resin base material and an inorganic layer, but since oxygen permeability is particularly low among resins, the deterioration of the quantum dot phosphor is suppressed. It has a sufficient oxygen barrier property.

The proportion of ethylene-derived structural units (ethylene content) in EVOH is not particularly limited, and can be selected in consideration of desired characteristics of the wavelength conversion member and the like. From the viewpoint of oxygen barrier properties, the ethylene content is preferably low, and from the viewpoint of strength and water resistance, the ethylene content is preferably high. For example, the ethylene content in EVOH is preferably 20 mol% to 50 mol%, more preferably 25 mol% to 45 mol%, and further preferably 30 mol% to 40 mol%.

The average thickness of the coating material containing EVOH is, for example, preferably 20 μm or more, and more preferably 50 μm or more. When the average thickness is 20 μm or more, functions such as barrier properties tend to be sufficient.
The average thickness of the coating material containing EVOH is, for example, preferably 150 μm or less, and more preferably 125 μm or more. When the average thickness is 150 μm or less, a decrease in light transmittance tends to be suppressed.

The oxygen permeability of the coating material is, for example, preferably 0.5 cm ³ /(m ² ·day·atm) or less, more preferably 0.3 cm ³ /(m ² ·day·atm) or less. , 0.1 cm ³ /(m ² ·day·atm) or less is more preferable.

The oxygen transmission rate of the coating material can be measured under the conditions of 20° C. and relative humidity of 65% using an oxygen transmission rate measuring device (eg, MOCON, OX-TRAN).

The upper limit of the water vapor transmission rate of the coating material is not particularly limited, but may be, for example, 1×10 ⁻¹ g/(m ² ·day) or less.

The water vapor transmission rate of the coating material can be measured using a water vapor transmission rate measuring device (for example, AQUATRAN, MOCON) under the environment of 40° C. and relative humidity of 90%.

The wavelength conversion member of the present disclosure has a total light transmittance of preferably 55% or more, more preferably 60% or more, and further preferably 65% or more, from the viewpoint of further improving the light utilization efficiency. More preferable. The total light transmittance of the wavelength conversion member can be measured according to the measuring method of JIS K 7136:2000.

In addition, the wavelength conversion member of the present disclosure preferably has a haze of 95% or more, more preferably 97% or more, and further preferably 99% or more, from the viewpoint of further improving light utilization efficiency. preferable. The haze of the wavelength conversion member can be measured according to the measuring method of JIS K 7136:2000.

FIG. 1 shows an example of a schematic configuration of the wavelength conversion member. However, the wavelength conversion member of the present disclosure is not limited to the configuration of FIG. Further, the sizes of the cured product and the covering material in FIG. 1 are conceptual, and the relative relationship of the sizes is not limited to this. In each drawing, the same members are designated by the same reference numerals, and duplicate description may be omitted.

The wavelength conversion member 10 shown in FIG. 1 has a cured product 11 which is a cured product in the form of a film, and film-shaped covering materials 12A and 12B provided on both surfaces of the cured product 11. The types and average thicknesses of the coating material 12A and the coating material 12B may be the same or different.

The wavelength conversion member having the configuration shown in FIG. 1 can be manufactured, for example, by the following known manufacturing method.

First, the curable composition is applied to the surface of a film-shaped coating material (hereinafter, also referred to as “first coating material”) that is continuously conveyed to form a coating film. The method of applying the curable composition is not particularly limited, and examples thereof include a die coating method, a curtain coating method, an extrusion coating method, a rod coating method and a roll coating method.

Next, a film-like coating material that is continuously conveyed (hereinafter, also referred to as “second coating material”) is attached onto the coating film of the curable composition.

Then, the coating film is cured by irradiating active energy rays from the coating material side of the first coating material and the second coating material which can transmit active energy rays, thereby forming a cured product. After that, the wavelength conversion member having the configuration shown in FIG. 1 can be obtained by cutting out into a prescribed size.

If neither the first coating material nor the second coating material is permeable to the active energy rays, the coating film is irradiated with the active energy rays before the second coating material is attached to cure the cured product. It may be formed.

<Backlight unit>
A backlight unit of the present disclosure includes the above-described wavelength conversion member of the present disclosure and a light source.

The backlight unit is preferably a multi-wavelength light source from the viewpoint of improving color reproducibility. As a preferred embodiment, the blue light having an emission center wavelength in the wavelength range of 430 nm to 480 nm, the emission intensity peak having a half width of 100 nm or less, and the emission center wavelength in the wavelength range of 520 nm to 560 nm, A back light which emits green light having an emission intensity peak having a full width at half maximum of 100 nm or less, and red light having an emission center wavelength in the wavelength range of 600 nm to 680 nm and having an emission intensity peak having a full width at half maximum of 100 nm or less. A light unit can be mentioned. The full width at half maximum of the emission intensity peak means the full width at half maximum (Full Width at Half Maximum, FWHM), which is the peak width at a half height of the peak height.

From the viewpoint of further improving color reproducibility, the emission center wavelength of blue light emitted by the backlight unit is preferably in the range of 440 nm to 475 nm. From the same viewpoint, the emission center wavelength of the green light emitted by the backlight unit is preferably in the range of 520 nm to 545 nm. From the same viewpoint, the emission center wavelength of the red light emitted by the backlight unit is preferably in the range of 610 nm to 640 nm.

Further, from the viewpoint of further improving color reproducibility, the half width of each emission intensity peak of blue light, green light, and red light emitted by the backlight unit is preferably 80 nm or less, and 50 nm or less. More preferably, it is more preferably 40 nm or less, still more preferably 30 nm or less, and most preferably 25 nm or less.

As the light source of the backlight unit, for example, a light source that emits blue light having an emission center wavelength in the wavelength range of 430 nm to 480 nm can be used. Examples of the light source include an LED (Light Emitting Diode) and a laser. When using a light source that emits blue light, the wavelength conversion member preferably includes at least a quantum dot phosphor R that emits red light and a quantum dot phosphor G that emits green light. Thereby, white light can be obtained from the red light and the green light emitted from the wavelength conversion member and the blue light transmitted through the wavelength conversion member.

Further, as the light source of the backlight unit, for example, a light source that emits ultraviolet light having an emission center wavelength in the wavelength range of 300 nm to 430 nm can be used. Examples of the light source include an LED and a laser. When using a light source that emits ultraviolet light, the wavelength conversion member preferably includes the quantum dot phosphor R and the quantum dot phosphor G, and the quantum dot phosphor B that emits blue light when excited by excitation light. Thereby, white light can be obtained from the red light, the green light, and the blue light emitted from the wavelength conversion member.

The backlight unit of the present disclosure may be of an edge light type or a direct type.

FIG. 2 shows an example of a schematic configuration of an edge light type backlight unit. However, the backlight unit of the present disclosure is not limited to the configuration of FIG. Further, the sizes of the members in FIG. 2 are conceptual, and the relative size relationship between the members is not limited to this.

The backlight unit 20 shown in FIG. 2 includes a light source 21 for emitting the blue light L _B, a light guide plate 22 to be emitted guiding the blue light L _B emitted from the light source 21, the light guide plate 22 and disposed to face The wavelength conversion member 10, the retroreflective member 23 arranged to face the light guide plate 22 via the wavelength conversion member 10, and the reflection plate 24 arranged to face the wavelength conversion member 10 via the light guide plate 22. .. The wavelength conversion member 10 emits the red light L _R and the green light L _G by using a part of the blue light L _B as the excitation light, and the red light L _R and the green light L _G, and the blue light L that is not the excitation light. _B and _B are emitted. The red light L _R , the green light L _G , and the blue light L _B cause the retroreflective member 23 to emit white light L _W.

<Image display device>
The image display device of the present disclosure includes the above-described backlight unit of the present disclosure. The image display device is not particularly limited, and examples thereof include a liquid crystal display device.

FIG. 3 shows an example of a schematic configuration of a liquid crystal display device. However, the liquid crystal display device of the present disclosure is not limited to the configuration of FIG. 3. Further, the sizes of the members in FIG. 3 are conceptual, and the relative size relationship between the members is not limited to this.

The liquid crystal display device 30 shown in FIG. 3 includes a backlight unit 20 and a liquid crystal cell unit 31 arranged to face the backlight unit 20. The liquid crystal cell unit 31 is configured such that the liquid crystal cell 32 is arranged between the polarizing plate 33A and the polarizing plate 33B.

The driving method of the liquid crystal cell 32 is not particularly limited, and includes a TN (Twisted Nematic) method, an STN (Super Twisted Nematic) method, a VA (Virtual Alignment) method, an IPS (In-Plane-Switching Refilling) method, and an OCB (Optical Refilling) method. A method etc. are mentioned.

<Example 1 of curable composition>
Example 1 of the curable composition of the present disclosure includes a quantum dot phosphor, a polyfunctional (meth)acrylate compound, and a thiol compound, the thiol compound includes a polyfunctional thiol compound, and the polyfunctional thiol compound is It has at least one thiol group to which a primary carbon atom is bound, and the ratio of the total number of thiol groups in the thiol compound to the total number of carbon-carbon double bonds in the polyfunctional (meth)acrylate compound (thiol The total number of groups/the total number of carbon-carbon double bonds) is 0.5 to 4.0. This makes it possible to provide a curable composition containing a quantum dot phosphor and capable of producing a wavelength conversion member having excellent light resistance and wet heat resistance in a high temperature environment.

<Example 2 of curable composition>
Example 2 of the curable composition of the present disclosure includes a quantum dot phosphor, a polyfunctional (meth)acrylate compound, and a thiol compound, and the thiol compound includes a polyfunctional thiol compound, and the polyfunctional (meth)acrylate. The compound has 2 to 5 (meth)acryloyl groups in one molecule, and the total number of thiol groups in the thiol compound relative to the total number of carbon-carbon double bonds in the polyfunctional (meth)acrylate compound. The number ratio (total number of thiol groups/total number of carbon-carbon double bonds) may be 0.5 to 4.0. This makes it possible to provide a curable composition containing a quantum dot phosphor and capable of producing a wavelength conversion member having excellent light resistance and wet heat resistance in a high temperature environment.

In Examples 1 and 2 of the curable composition, the respective constituents of the curable composition described in the item of the wavelength conversion member and the like may be appropriately combined. For example, the preferable numerical range of the total number of thiol groups/the total number of carbon-carbon double bonds in Examples 1 and 2 of the curable composition is appropriately combined with the numerical range presented in the items such as the above-mentioned wavelength conversion member. May be.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

<Examples 1 to 4 and Comparative Examples 1 and 2>
(Preparation of curable composition)
The curable compositions of Examples 1 to 4 and Comparative Examples 1 and 2 were prepared by mixing the components shown in Table 1 with the blending amounts (unit: parts by mass) shown in the same table.
As the polyfunctional (meth)acrylate compound, ethoxylated bisphenol A diacrylate (Shin-Nakamura Chemical Co., Ltd., ABE-300) was used.
In addition, pentaerythritol tetrakis(3-mercaptopropionate) (SC Organic Chemical Co., Ltd., PEMP) was used as the polyfunctional thiol compound.
As the photopolymerization initiator, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (BASF Corporation, IRGACURE TPO) was used.
As the quantum dot phosphor dispersion liquid, CdSe/ZnS (core/shell) dispersion liquid (Nanosys, Gen3.5 QD Concentrate) was used. Isobornyl acrylate was used as the dispersion medium of this CdSe/ZnS (core/shell) dispersion. The CdSe/ZnS (core/shell) dispersion contains 86% by mass or more of isobornyl acrylate.
In addition, acetic acid was used as the carboxylic acid.
In addition, titanium oxide (Chemours, TYPURE R-706, particle diameter 0.36 μm) was used as a white pigment. On the surface of titanium oxide, a first metal oxide layer containing silicon oxide, a second metal oxide layer containing aluminum oxide, and an organic material layer containing a polyol compound, a first metal oxide layer, a second metal oxide layer. And an organic material layer in this order.

(Production of wavelength conversion member)
Each curable composition obtained above was applied onto a PET film (Toyobo Co., Ltd., A4300) (covering material) having an average thickness of 100 μm to form a coating film. A PET film (Toyobo Co., Ltd., A4300) (coating material) having a thickness of 100 μm is bonded onto this coating film, and ultraviolet rays are irradiated using an ultraviolet irradiation device (eye graphics Co., Ltd.) (irradiation amount: 1000 mJ/cm ² ). By doing so, a wavelength conversion member in which the coating material was disposed on both surfaces of the cured product was obtained.

<Evaluation>
The following evaluation items were measured and evaluated using the wavelength conversion members obtained in Examples 1 to 4 and Comparative Examples 1 and 2. The results are shown in Table 2. In Comparative Example 2, the ratio of unreacted thiol groups in the curable composition was too large, and the coating could not be successfully prepared due to insufficient curing, so that the light resistance and wet heat resistance could not be evaluated.

(Light resistance)
Each wavelength conversion member obtained above was cut into a size of 17 mm in diameter to prepare an evaluation sample. The initial emission intensity of the evaluation sample was measured with a fiber multi-channel spectroscope (Ocean View, Inc., Ocean Photonics Co., Ltd.). Next, the evaluation sample was installed in a high-intensity tester Light BOX (Nanosys) (LED peak wavelength 448 nm), and the test was conducted under an environment of an illuminance of 150 mW/cm ² and a constant temperature bath of 85° C. After 24 hours, the evaluation sample was taken out and the relative emission intensity retention rate 1 of the wavelength conversion member was calculated according to the following formula.
Relative emission intensity retention ratio 1: (RLb1/RLa)×100
RLa: initial relative luminescence intensity RLb1: 150 mW/cm ² , relative luminescence intensity after 24 hours in an environment of 85° C. Note that the higher the relative luminescence intensity retention rate 1 is, the more excellent the light resistance of the wavelength conversion member is.

(Moisture and heat resistance)
Each of the wavelength conversion members obtained above was cut into a size of 100 mm in width and 100 mm in length, and then placed in a constant temperature and humidity chamber of 65° C. and 95% RH (relative humidity) and left standing for 400 hours. The relative emission intensity retention rate 2 of the wavelength conversion member was calculated according to the formula.
Relative emission intensity retention rate 2: (RLb2/RLa)×100
RLa: initial relative luminescence intensity RLb2: 65° C. 95% RH, relative luminescence intensity after 400 hours In addition, the higher the numerical value of the relative luminescence intensity retention rate 2 is, the more excellent the moist-heat resistance is.

(Calculation of FT-IR peak area ratio and reaction rate)
The surface of each curable composition obtained above and the surface of the cured product in each wavelength conversion member obtained above were subjected to ATR analysis using FT-IR Spectrometer (Perkin Elmer). For each wavelength conversion member, the PET film was peeled off and the surface of the cured product was analyzed by ATR. The background measurement was performed with air, and FT-IR measurement was performed under the condition that the number of times of integration was 16 times, and the FT-IR peak area ratio and reaction rate were calculated according to the following formulas.
[FT-IR peak area ratio in curable composition]
V1: peak attributed to S-H stretching vibration (peak wavelength: 2569cm ^-1) peak area of V2: peak attributed to C-H stretching vibration (peak wavelength: 2957cm ^-1) peak area of V3: C = C Peak area FT-IR peak area ratio of peak (peak wavelength: 1637 cm ⁻¹ ) attributable to stretching vibration: V1/V2=A
FT-IR peak area ratio: V3/V2=B
[FT-IR peak area ratio in cured product]
V4: peak attributed to S-H stretching vibration (peak wavelength: 2569cm ^-1) peak area V5: peak attributed to C-H stretching vibration (peak wavelength: 2957cm ^-1) peak area of V6: C = C Peak area attributable to stretching vibration (peak wavelength: 1637 cm ⁻¹ ) FT-IR peak area ratio: V4/V5=C
FT-IR peak area ratio: V6/V5=D
[Reaction rate]
Reaction rate of thiol group: 100-100 x (C/A)
Reaction rate of carbon-carbon double bond: 100-100 x (D/B)

As can be seen from Table 2, in Examples 1 to 4 in which the reaction rate of the thiol group was smaller than that in Comparative Example 1, the light resistance and the wet heat resistance were excellent. In Comparative Example 2, the ratio of unreacted thiol groups in the curable composition was too large, and a cured product could not be produced well.

[Comparative Example 3]
In Example 1, DPHA (dipentaerythritol hexaacrylate), which is a compound having 6 acryloyl groups in one molecule, was used as the polyfunctional (meth)acrylate instead of ABE-300, and the polyfunctional thiol compound was used. , 4-bis(3-mercaptobutyryloxy)butane (Showa Denko KK, Karenz MT (registered trademark)) which is a compound having only a thiol group having a secondary carbon atom bonded as a thiol group instead of PEMP. A curable composition was prepared in the same manner as in Example 1 except that BD1) was used and the composition of each component of the curable composition was as shown in Table 3, to produce a wavelength conversion member.
Also in Comparative Example 3, each evaluation item was measured and evaluated in the same manner as in Example 1 described above. The results are shown in Table 3.

In Comparative Example 3, the reaction rate of the thiol group was larger than that in Examples 1 to 4, and particularly the moist heat resistance was worse than that in Examples 1 to 4.

The disclosure of PCT/JP2018/012586, filed March 27, 2018, is hereby incorporated by reference in its entirety.
All documents, patent applications, and technical standards mentioned herein are to the same extent as if each individual document, patent application, and technical standard was specifically and individually noted to be incorporated by reference. Incorporated herein by reference.

Claims (16)

Quantum dot phosphor, and a polyfunctional thiol compound, having a cured product obtained by curing a curable composition containing at least,
A wavelength conversion member having a reaction rate of thiol groups of the cured product of 15% to 65%. Ratio (V4) of the peak area (V4) attributable to the SH stretching vibration and the peak area (V5) attributable to the CH stretching vibration in the cured product measured by a Fourier transform infrared spectrophotometer. /V5) is 0.015 to 0.060, The wavelength conversion member according to claim 1. The wavelength conversion member according to claim 1, wherein the cured product has an alkyleneoxy structure. The cured product is obtained by curing the curable composition further containing a polyfunctional (meth)acrylate compound,
The wavelength conversion member according to any one of claims 1 to 3, wherein a reaction rate of carbon-carbon double bonds in the cured product is 90% or more. The wavelength conversion member according to claim 4, wherein the polyfunctional (meth)acrylate compound has an alkyleneoxy group. The wavelength conversion member according to claim 5, wherein the polyfunctional (meth)acrylate compound has 2 to 5 (meth)acryloyl groups in one molecule. The wavelength conversion member according to any one of claims 1 to 6, wherein the quantum dot phosphor includes a compound containing at least one of Cd and In. The wavelength conversion member according to claim 1, further comprising a coating material that covers at least a part of the cured product. The cured product has a sulfide structure bonded to two carbon atoms, and both of the carbon atoms bonded to the sulfide structure are primary carbon atoms. The wavelength conversion member according to. A backlight unit comprising the wavelength conversion member according to any one of claims 1 to 9 and a light source. An image display device comprising the backlight unit according to claim 10. Including a quantum dot phosphor, a polyfunctional (meth)acrylate compound, and a thiol compound,
The thiol compound includes a polyfunctional thiol compound,
The polyfunctional thiol compound has at least one thiol group bonded with a primary carbon atom,
The ratio of the total number of thiol groups in the thiol compound to the total number of carbon-carbon double bonds in the polyfunctional (meth)acrylate compound (total number of thiol groups/total number of carbon-carbon double bonds) is 0. Curable composition which is 0.5-4.0. Including a quantum dot phosphor, a polyfunctional (meth)acrylate compound, and a thiol compound,
The thiol compound includes a polyfunctional thiol compound,
The polyfunctional (meth)acrylate compound has 2 to 5 (meth)acryloyl groups in one molecule,
The ratio of the total number of thiol groups in the thiol compound to the total number of carbon-carbon double bonds in the polyfunctional (meth)acrylate compound (total number of thiol groups/total number of carbon-carbon double bonds) is 0. Curable composition which is 0.5-4.0. The curable composition according to claim 12, wherein the polyfunctional (meth)acrylate compound has 2 to 5 (meth)acryloyl groups in one molecule. The curable composition according to claim 13, wherein the polyfunctional thiol compound has at least one thiol group bonded with a primary carbon atom. The curable composition according to any one of claims 12 to 15, wherein the polyfunctional (meth)acrylate compound has an alkyleneoxy group.