Curable composition for ink jet, led module, and method for producing led module

Abstract

The present invention provides a curable composition for inkjet, which can improve inkjet ejection properties and can suppress discoloration when an LED module obtained from an oblique view. This curable composition for inkjet contains: a photocurable compound which has a total of two or more photopolymerizable functional groups and does not have a cyclic ether group; a thermosetting compound having a cyclic ether group; a photopolymerization initiator; a heat curing agent; a colorant; the present invention relates to a curable composition for ink jet, the curable composition for ink jet comprises a colorant and a dispersant, the colorant comprises carbon black, the average particle size of the carbon black is 40-100 nm (inclusive), and when a cured product of the curable composition for ink jet having a thickness of 30 [mu] m is irradiated with light, the b * value of reflected light of the cured product in the L * a * b * color system is-3-3 (inclusive).

Description

Technical Field

[0001] The present invention relates to a curable composition for inkjet use that is applied by an inkjet method. Further, the present invention relates to an LED module using the curable composition for inkjet and a method for manufacturing the LED module. Background Art

[0002] Light-emitting diode (LED) chips are used in various electronic device applications. For example, an LED package in which a lead frame and an LED chip are arranged on a substrate and the lead frame and the LED chip are sealed with resin is widely used.

[0003] In recent years, large display devices have been used for advertisements, guide plates, etc. As a large display device, a display device obtained by bonding a plurality of the LED packages to prepare a small LED module is known. In the display device, for example, the LED can be lit in white, red, blue, green, etc. for display.

[0004] Patent Document 1 below discloses a self-luminous display body including: a light-emitting module in which a plurality of light-emitting elements are mounted on a wiring substrate; a black sealing material sheet containing an olefin resin and having a visible light transmittance of 5% or more and 70% or less; and a transparent optical layer. In the self-luminous display body, the black sealing material sheet is laminated on the light-emitting module so as to cover the surfaces of the light-emitting elements and the wiring substrate.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-204905 Summary of the Invention

[0008] Technical Problem to be Solved by the Invention

[0009] However, when preparing an LED package, an LED module, and a display device using the existing sealing material sheet described in Patent Document 1, there is a technical problem that color change easily occurs when the LED module with the LED lit is observed obliquely.

[0010] In order to solve the above technical problem, methods of disposing a partition wall in the gap between a plurality of LED chips or disposing a surface layer above the LED chip have been studied.

[0011] The inventors of the present invention tried to contain a colorant such as carbon black in the curable composition to form a partition wall and a surface layer in order to suppress color change when the LED module is observed obliquely. However, the inventors found that when carbon black is blended in the conventional curable composition, the ejectability of the inkjet device easily deteriorates.

[0012] An object of the present invention is to provide a curable composition for inkjet, which can improve the inkjet ejectability and can suppress color change when observing an LED module obliquely. Another object of the present invention is to provide an LED module using the curable composition for inkjet and a method for manufacturing the LED module.

[0013] Means for solving the technical problem

[0014] In this specification, the following curable composition for inkjet, LED module, and method for manufacturing the LED module are disclosed.

[0015] Item 1. A curable composition for inkjet, comprising:

[0016] A photocurable compound having two or more photopolymerizable functional groups and not having a cyclic ether group,

[0017] A thermosetting compound having a cyclic ether group,

[0018] A photoinitiator,

[0019] A thermosetting agent,

[0020] A colorant, and

[0021] A dispersant, wherein

[0022] the colorant contains carbon black,

[0023] the average particle size of the carbon black is 40 nm or more and 100 nm or less,

[0024] For a cured product of the curable composition for inkjet with a thickness of 30 μm, when the cured product is irradiated with light, the b* value of the reflected light of the cured product in the L*a*b* color system is -3 or more and 3 or less.

[0025] Item 2. The curable composition for inkjet according to Item 1, wherein

[0026] the acid value of the dispersant is 10 mgKOH / g or more and 150 mgKOH / g or less, and the amine value of the dispersant is 10 mgKOH / g or more and 100 mgKOH / g or less.

[0027] Item 3. The curable composition for inkjet according to Item 1 or 2, wherein

[0028] the photoinitiator contains an aminophenylethanone compound.

[0029] Item 4. The curable composition for inkjet according to any one of Items 1 to 3, wherein

[0030] In 100% by weight of the curable composition for inkjet, the content of the carbon black is 0.1% by weight or more and 5.0% by weight or less.

[0031] Item 5. The curable composition for inkjet according to any one of Items 1 to 4, wherein

[0032] the colorant further contains a colorant other than carbon black.

[0033] Item 6. The curable composition for inkjet according to any one of Items 1 to 5, wherein

[0034] the colorant further contains a phthalocyanine compound.

[0035] Item 7. The curable composition for inkjet according to any one of Items 1 to 6, wherein

[0036] the photocurable compound contains a photocurable compound having two or more (meth)acryloyl groups and having a dicyclopentadiene skeleton.

[0037] Item 8. The curable composition for inkjet according to any one of Items 1 to 7, wherein

[0038] the thermosetting compound contains 4-hydroxybutyl acrylate glycidyl ether.

[0039] Item 9. The curable composition for inkjet according to any one of Items 1 to 8, which is used for forming a partition wall in an LED module.

[0040] Item 10. An LED module, comprising:

[0041] a substrate;

[0042] an LED chip disposed on a first surface of the substrate; and

[0043] a partition wall disposed on the first surface of the substrate,

[0044] the partition wall is disposed on the first surface of the substrate so as to surround the LED chip,

[0045] the partition wall is a cured product of the curable composition for inkjet according to any one of Items 1 to 9.

[0046] Item 11. A method for manufacturing an LED module, comprising:

[0047] a coating step of coating the curable composition for inkjet according to any one of Items 1 to 9 on a first surface of a substrate by an inkjet method to form a composition layer;

[0048] The photocuring step irradiates light on the curable composition for inkjet to cure the curable composition for inkjet and form a B-stage product;

[0049] The thermosetting step thermally cures the B-stage product by heating to form a partition wall; and

[0050] The step of disposing an LED chip inside a region surrounded by the partition wall on the first surface of the substrate.

[0051] Advantages of the Invention

[0052] The curable composition for inkjet of the present invention is a curable composition for inkjet containing a photocurable compound having two or more photopolymerizable functional groups and not having a cyclic ether group, a thermosetting compound having a cyclic ether group, a photopolymerization initiator, a thermosetting agent, a colorant, and a dispersant. In the curable composition for inkjet of the present invention, the colorant contains carbon black, and the average particle size of the carbon black is 40 nm or more and 100 nm or less. In the curable composition for inkjet of the present invention, for a cured product of the curable composition for inkjet having a thickness of 30 μm, when light is irradiated on the cured product, the b* value of the reflected light of the cured product in the L*a*b* color system is -3 or more and 3 or less. In the curable composition for inkjet of the present invention, due to the above configuration, inkjet ejectability can be improved, and in addition, color change can be suppressed when observing the LED module obliquely. Description of the Drawings

[0053] Figure 1 (a) is a top view schematically showing an LED module obtained using the curable composition for inkjet of the first embodiment of the present invention, Figure 1 (b) is a cross-sectional view schematically showing the LED module.

[0054] Figure 2 is a cross-sectional view schematically showing an LED module obtained using the curable composition for inkjet of the second embodiment of the present invention.

[0055] Figure 3 (a) and Figure 3 (b) are cross-sectional views for explaining each step of the manufacturing method of the LED module shown in Figure 1 shown.

[0056] Figure 4 (c) and Figure 4 (d) are cross-sectional views for explaining each step of the manufacturing method of the LED module shown in Figure 1 shown.

[0057] Figure 5 (e) and Figure 5 (f) are for explainingFigure 1 Cross-sectional views of the respective steps of the method for manufacturing the LED module shown.

[0058] Figure 6 (g) is used to illustrate Figure 1 Cross-sectional views of the respective steps of the method for manufacturing the LED module shown. Detailed implementation mode

[0059] Hereinafter, the present invention will be described in detail.

[0060] (Curable composition for inkjet)

[0061] The curable composition for inkjet of the present invention (hereinafter, sometimes referred to as "curable composition") is used for inkjet coating.

[0062] The curable composition of the present invention contains the following components.

[0063] A photocurable compound having two or more photopolymerizable functional groups and not having a cyclic ether group (hereinafter, sometimes referred to as "photocurable compound (A)");

[0064] A thermosetting compound having a cyclic ether group (hereinafter, sometimes referred to as "thermosetting compound (B)");

[0065] A photopolymerization initiator (C);

[0066] A thermosetting agent (D);

[0067] A colorant (E);

[0068] A dispersant (F).

[0069] The curable composition has photocurability and thermosetting properties. The curable composition is preferably cured by irradiation with light and heating for use. The curable composition is more preferably cured by heating after being cured by irradiation with light for use.

[0070] The curable composition can be coated by an inkjet method. When the curable composition is coated by an inkjet method, an inkjet device is used. The inkjet device has an inkjet head. The inkjet head has an inkjet nozzle. The curable composition is different from compositions coated by screen printing and compositions coated by a dispenser, etc.

[0071] The curable composition is, for example, suitable for use in a light-emitting diode (LED) (the use of the curable composition in a light-emitting diode (LED)). The curable composition is preferably a curable composition for inkjet and for LED. The curable composition is particularly suitable for forming a partition wall in an LED module (the use of the curable composition for forming a partition wall in an LED module). The curable composition is preferably a curable composition for forming a partition wall. The curable composition is suitable for forming a partition wall in the gap between a plurality of LED chips (the use of the curable composition for forming a partition wall in the gap between a plurality of LED chips). The curable composition is suitable for forming a partition wall at the peripheral portion of the mounting area of an LED chip (the use of the curable composition for forming a partition wall at the peripheral portion of the mounting area of an LED chip). Thereby, the utilization efficiency of the light generated from the LED chip can be improved, and color change when observing the LED module obliquely can be suppressed. It should be noted that in the case where the LED chip is an LED chip that emits ultraviolet light (UV-LED chip), sometimes the luminous efficiency of the LED chip itself is low. By using the curable composition, the light extraction efficiency can be improved, and thus the curable composition is particularly suitable for the case where the LED chip is an LED chip that emits ultraviolet light.

[0072] In addition, the curable composition is suitable for forming a surface layer in an LED module. The curable composition is preferably a curable composition for forming a surface layer. The curable composition is suitable for forming a surface layer disposed above a plurality of LED chips. The surface layer may be disposed above a plurality of LED chips, may be disposed above the gap between a plurality of LED chips, or may be disposed above both the plurality of LED chips and the gap. The surface layer may be disposed above a light-transmitting layer disposed above a plurality of LED chips. Thereby, color change can be suppressed when observing the LED module obliquely.

[0073] The curable composition is particularly suitable for LED modules in the COB method and the COG method. The curable composition is more preferably used as a curable composition for forming a partition wall or a curable composition for forming a surface layer in an LED module in the COB method and the COG method. In addition, the curable composition is also suitable for use as a black matrix of an LED module or a curable composition for forming a frame of an LED module.

[0074] The curable composition can also be used for uses other than LEDs. The curable composition can also be suitably used, for example, as a marking material for electronic components, a curable composition for forming a light shielding material for an infrared sensor, and a curable composition for forming a light shielding material for a camera module.

[0075] In the curable composition, for the cured product of the curable composition with a thickness of 30 μm, when light is irradiated on the cured product, the b* value of the reflected light of the cured product in the L*a*b* color system is -3 or more and 3 or less. It should be noted that if the b* value is less than -3, when the LED module with the LED lit is observed obliquely, it becomes a bluish hue, and color change cannot be sufficiently suppressed. In addition, if the b* value exceeds 3, when the LED module with the LED lit is observed obliquely, it becomes a reddish hue, and color change cannot be sufficiently suppressed.

[0076] The b* value can be measured, for example, by the following method. After coating the curable composition on the surface of a glass substrate (thickness: 700 mm) using an inkjet device, ultraviolet light (UV-LED) with an accumulated light amount of 1000 mJ / cm 2 is irradiated in such a manner that the illuminance at a wavelength of 365 nm becomes 1000 mW / cm 2 to prepare a B-stage product of the curable composition. The obtained B-stage product is heated at 160 °C for 1 hour to form a cured product of the curable composition with a thickness of 30 μm. Light is irradiated from directly above (the surface side opposite to the glass substrate) of the cured product with a thickness of 30 μm, and the reflected light of the cured product is measured from directly above the cured product to obtain the L* value, a* value, and b* value in the L*a*b* color system. It should be noted that the L* value, a* value, and b* value are preferably measured using a spectrophotometer (e.g., "CM-26dG" manufactured by Konica Minolta Inc.) in accordance with JIS Z8781-4:2013.

[0077] The inventors focused on the influence of short-wavelength scattered light and the color of the cured product of the curable composition on the color change when observing the LED module obliquely. The inventors conducted in-depth research and found that the yellowing of the cured product of the curable composition (especially the cured product of a thermosetting compound or a photocurable compound) has a great influence on the color change when observing the LED module obliquely. In addition, the inventors found that when the cured product of the curable composition (especially the cured product of a thermosetting compound or a photocurable compound) turns yellow, there is a tendency for the b* value of the reflected light of the cured product in the L*a*b* color system to increase. In the curable composition of the present invention, since the b* value is controlled within a specific range, the influence of short-wavelength scattered light and the color of the cured product of the curable composition can be suppressed, and the color change when observing the LED module obliquely can be suppressed.

[0078] The light irradiated on the cured product is not particularly limited. The light can be ultraviolet light, can be an electron beam, can be an α-ray, can be a β-ray, can be a γ-ray, can be an X-ray, can be a neutron ray, etc. The light can be white light, can be blue light, can be red light, or can be green light. The wavelength of the light is preferably 250 nm or more, more preferably 300 nm or more, preferably 850 nm or less, and more preferably 800 nm or less.

[0079] The b* value is preferably -2.5 or more, more preferably -2 or more, further preferably -1 or more, preferably 2.5 or less, more preferably 2 or less, and further preferably 1 or less. When the b* value is within the above lower limit and the above upper limit, color change can be better suppressed when observing the LED module obliquely.

[0080] The a* value is preferably -5 or more, more preferably -4 or more, further preferably -3 or more, preferably 4 or less, more preferably 3 or less, and further preferably 2 or less. If the a* value is within the above lower limit and the above upper limit, color change can be more favorably suppressed when observing the LED module obliquely.

[0081] The L* value is preferably 1 or more, more preferably 3 or more, further preferably 10 or more, particularly preferably 20 or more, most preferably 30 or more, preferably 90 or less, more preferably 80 or less, and further preferably 70 or less. When the L* value is within the above lower limit and the above upper limit, color change can be better suppressed when observing the LED module obliquely.

[0082] The color difference ΔE*ab calculated from the L* value, a* value, and b* value is preferably 10 or less, more preferably 9 or less, further preferably 8 or less, particularly preferably 7 or less, and most preferably 0. If the color difference ΔE*ab is within the above upper limit, light can be more favorably dispersed, and thus color change can be more effectively suppressed when observing the LED module obliquely. The lower limit of the color difference ΔE*ab is not particularly limited. The color difference ΔE*ab can be 0 or more, can be 0.5 or more, or can be 1.0 or more.

[0083] As a method for adjusting the b* value to the preferred range, there can be mentioned a method of using carbon black having a specific average particle size described later, a method of using in combination two or more kinds of carbon black having different average particle sizes, a method of adjusting the content of carbon black, a method of selecting a thermosetting compound and a photocurable compound that are not easily yellowed, a method of adding an antioxidant, and a method of further adding a colorant, etc. In particular, by using carbon black having a small average particle size, the b* value can be increased, and by using carbon black having a large average particle size, the b* value can be decreased.

[0084] From the viewpoint of better coating the curable composition by an inkjet method, the curable composition is preferably liquid at 25°C. The liquid state also includes a paste state.

[0085] The viscosity (η25) of the curable composition at 25°C is preferably 40 mPa·s or more, more preferably 60 mPa·s or more, still more preferably 80 mPa·s or more, preferably 500 mPa·s or less, more preferably 400 mPa·s or less, and still more preferably 300 mPa·s or less. If the viscosity (η25) is within the above lower limit and the above upper limit, the inkjet ejectability can be further improved.

[0086] The viscosity (η25) is preferably measured using an E-type viscometer (for example, "TVE22L" manufactured by Toki Sangyo Co., Ltd.) and the like for the curable composition just after preparation at 25°C and 10 rpm.

[0087] When ejecting using the inkjet device, it is preferably ejected in a state heated to 40°C or more and 100°C or less. From the viewpoints of improving the height accuracy of the partition walls and the thickness accuracy of the surface layer and making it difficult to generate voids in the partition walls and the surface layer, it is preferable to perform coating while circulating the curable composition.

[0088] Preferably, the inkjet device has: an ink tank that stores the curable composition; an ejection part that is connected to the ink tank and ejects the curable composition; and a circulation flow path part that has one end connected to the ejection part, the other end connected to the ink tank, and the curable composition flows inside.

[0089] Preferably, in the inkjet device, after the curable composition moves from the ink tank to the ejection part, the curable composition that has not been ejected from the ejection part flows in the circulation flow path part and moves to the ink tank, thereby performing coating while circulating the curable composition. When performing coating while circulating the curable composition, the height accuracy of the partition walls and the thickness accuracy of the surface layer can be improved, and it is possible to make it difficult to generate voids in the partition walls and the surface layer.

[0090] The glass transition temperature (Tg) of the cured product of the curable composition is preferably 80°C or more, more preferably 90°C or more, still more preferably 100°C or more, preferably 190°C or less, more preferably 180°C or less, and still more preferably 170°C or less. If the glass transition temperature (Tg) of the cured product of the curable composition is within the above lower limit and the above upper limit, the adhesion between the partition walls and the surface layer and the inkjet target part can be improved.

[0091] The glass transition temperature (Tg) of the cured product of the curable composition can be measured using a dynamic viscoelasticity measuring device under the conditions of a heating rate of 10 °C / minute and a measurement frequency of 10 Hz. Examples of the dynamic viscoelasticity measuring device include "DVA-200" manufactured by IT Measurement Control Co., Ltd.

[0092] The cured product of the curable composition is obtained, for example, by the following method. After coating the curable composition on the surface of a glass substrate using an inkjet device, ultraviolet rays (UV-LED) with an accumulated light quantity of 1000 mJ / cm 2 are irradiated in such a manner that the illuminance at a wavelength of 365 nm becomes 1000 mW / cm 2 to prepare a B-stage product of the curable composition. The obtained B-stage product is heated at 160 °C for 1 hour to form a cured product of the curable composition.

[0093] Hereinafter, the details of each component that can be used in the curable composition of the present invention will be described. In this specification, "(meth)acryloyl" means one or both of "acryloyl" and "methacryloyl", and "(meth)acrylate" means one or both of "acrylate" and "methacrylate".

[0094] <Photocurable compound (A) having two or more photopolymerizable functional groups and not having a cyclic ether group>

[0095] The curable composition contains a photocurable compound (A) having two or more photopolymerizable functional groups and not having a cyclic ether group.

[0096] Since the curable composition contains the photocurable compound (A), the inkjet ejectability can be further improved, and the curable composition can be accurately arranged.

[0097] Examples of the photopolymerizable functional group include (meth)acryloyl and vinyl. From the viewpoint of effectively performing a photocuring reaction, the photopolymerizable functional group is preferably at least one photopolymerizable functional group selected from (meth)acryloyl and vinyl.

[0098] The photocurable compound (A) may have two or more (meth)acryloyl groups, may have two or more vinyl groups, or may have both (meth)acryloyl groups and vinyl groups. The photocurable compound (A) may not have (meth)acryloyl groups, or may not have vinyl groups. The photocurable compound (A) may be a photocurable compound (A) having two or more (meth)acryloyl groups and not having a cyclic ether group, or may be a photocurable compound (A) having two or more vinyl groups and not having a cyclic ether group. The photocurable compound (A) may be a photocurable compound (A) having both (meth)acryloyl groups and vinyl groups and not having a cyclic ether group.

[0099] The photocurable compound (A) having two or more (meth)acryloyl groups and not having a cyclic ether group may be a bifunctional (meth)acrylate compound, may be a (meth)acrylate compound having two or more functional groups, may be a trifunctional (meth)acrylate compound, or may be a (meth)acrylate compound having three or more functional groups. The photocurable compound (A) may be a (meth)acrylate compound having 20 or fewer functional groups, may be a (meth)acrylate compound having 10 or fewer functional groups, or may be a (meth)acrylate compound having 5 or fewer functional groups. The number of functional groups corresponds to the number of (meth)acryloyl groups. The photocurable compound (A) may be used alone or in combination of two or more.

[0100] The photocurable compound (A) having two or more (meth)acryloyl groups and not having a cyclic ether group may have two, may have two or more, may have three, may have three or more, may have 20 or fewer, may have 10 or fewer, or may have 5 or fewer.

[0101] From the viewpoint of suppressing discoloration (improving heat resistance) even when storing or using the obtained LED module at a high temperature, the photocurable compound (A) preferably contains a photocurable compound having an alicyclic skeleton.

[0102] Examples of the bifunctional (meth)acrylate compound having an alicyclic skeleton include ethoxylated cyclohexanemethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, 1,3-adamantanediol di(meth)acrylate, and propoxylated cyclohexanemethanol di(meth)acrylate.

[0103] Examples of the trifunctional (meth)acrylate compound having an alicyclic skeleton include pentaerythritol triacrylate-isophorone diisocyanate-urethane prepolymer.

[0104] From the viewpoint of suppressing discoloration (improving heat resistance) even when the obtained LED module is stored or used at high temperatures, the alicyclic skeleton is preferably a dicyclopentadiene skeleton.

[0105] From the viewpoint of improving the adhesion between the partition wall and the surface layer and the inkjet target portion, the photocurable compound (A) preferably contains a (meth)acrylate compound represented by the following formula (1).

[0106] [Chemical formula 1]

[0107]

[0108] In the formula (1), R1 and R2 each represent a hydrogen atom or a methyl group, and R3 represents an alkylene group.

[0109] In the formula (1), R1 and R2 may be the same or different.

[0110] From the viewpoint of improving the adhesion between the partition wall and the surface layer and the inkjet target portion, in the formula (1), the alkylene group of R3 preferably has 2 or more carbon atoms, more preferably 4 or more carbon atoms, still more preferably 6 or more carbon atoms, preferably 14 or less carbon atoms, more preferably 12 or less carbon atoms, and still more preferably 9 or less carbon atoms. From the viewpoint of improving the adhesion between the partition wall and the surface layer and the inkjet target portion, in the formula (1), R3 is particularly preferably an alkylene group having 6 or more and 9 or less carbon atoms.

[0111] Examples of the (meth)acrylate compound represented by the formula (1) include decanediol di(meth)acrylate, nonanediol di(meth)acrylate, and hexanediol di(meth)acrylate.

[0112] Examples of the photocurable compound (A) having two or more vinyl groups include vinyl ethers, ethylene derivatives, and styrene derivatives.

[0113] From the viewpoint of improving the adhesion between the partition wall and the surface layer and the inkjet target portion, the photocurable compound (A) preferably contains a photocurable compound having two or more (meth)acryloyl groups and a dicyclopentadiene skeleton. That is, the photocurable compound (A) preferably contains a photocurable compound having two or more (meth)acryloyl groups and a dicyclopentadiene skeleton and not having a cyclic ether group. From the viewpoint of improving the adhesion between the partition wall and the surface layer and the inkjet target portion, the photocurable compound (A) preferably contains a (meth)acrylate compound having two (meth)acryloyl groups and a dicyclopentadiene skeleton. It should be noted that in the dicyclopentadiene skeleton in the photocurable compound (A), the double bond portion of dicyclopentadiene can react. For example, the dicyclopentadiene skeleton in the photocurable compound (A) can be the skeleton represented by the following formula (2). In the following formula (2), the right end portion and the left end portion are bonding sites with other groups.

[0114] [Chemical formula 2]

[0115]

[0116] The photocurable compound (A) preferably contains ethoxylated cyclohexane methanol di(meth)acrylate or tricyclodecane dimethanol di(meth)acrylate, and more preferably contains tricyclodecane dimethanol di(meth)acrylate. Tricyclodecane dimethanol di(meth)acrylate has the skeleton represented by the formula (2).

[0117] The glass transition temperature (Tg) of the homopolymer of the photocurable compound (A) is preferably 100 °C or higher, more preferably 150 °C or higher, further preferably 190 °C or higher, preferably 250 °C or lower, and more preferably 220 °C or lower. If the glass transition temperature (Tg) of the homopolymer of the photocurable compound (A) is above the lower limit and below the upper limit, the adhesion between the partition wall and the surface layer and the inkjet target portion can be improved.

[0118] The glass transition temperature (Tg) of the homopolymer of the photocurable compound (A) refers to the glass transition temperature of a homopolymer having a degree of polymerization of 3000 to 4000 (preferably 3500).

[0119] The glass transition temperature can be measured in accordance with JIS K7121 using a dynamic viscoelasticity measuring device under the conditions of a heating rate of 10 °C / minute and a measuring frequency of 10 Hz. Examples of the dynamic viscoelasticity measuring device include "DVA-200" manufactured by IT Measurement Control Co., Ltd.

[0120] In 100% by weight of the curable composition, the content of the photocurable compound (A) is preferably 10% by weight or more, more preferably 20% by weight or more, still more preferably 30% by weight or more, preferably 80% by weight or less, more preferably 70% by weight or less, and still more preferably 60% by weight or less. When the content of the photocurable compound (A) is within the range from the lower limit to the upper limit, the inkjet ejectability can be further improved, and the curable composition can be accurately disposed.

[0121] <Thermosetting compound (B) having a cyclic ether group>

[0122] The curable composition contains a thermosetting compound (B) having a cyclic ether group.

[0123] Since the curable composition contains the thermosetting compound (B), the adhesiveness between the partition walls and the surface layer and the inkjet target portion can be improved.

[0124] Examples of the cyclic ether group include an epoxy group and an oxetanyl group. The epoxy group may be a glycidyl group. From the viewpoint of improving the adhesiveness between the partition walls and the surface layer and the inkjet target portion and more effectively suppressing color change when observing the LED module obliquely, the thermosetting compound (B) is preferably a thermosetting compound (epoxy compound) having an epoxy group. Only one kind of the thermosetting compound (B) may be used, or two or more kinds may be used in combination.

[0125] Examples of the epoxy compound include bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound, phenol novolac type epoxy compound, biphenyl type epoxy compound, biphenyl novolac type epoxy compound, biphenol type epoxy compound, naphthalene type epoxy compound, fluorene type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene type epoxy compound, anthracene type epoxy compound, epoxy compound having an adamantane skeleton, epoxy compound having a tricyclodecane skeleton, naphthylene ether type epoxy compound, and epoxy compound having a triazine nucleus in the skeleton.

[0126] The thermosetting compound (B) may be a photo- and thermosetting compound. The thermosetting compound (B) may have a cyclic ether group and a (meth)acryloyl group, or may have an epoxy group and a (meth)acryloyl group. The thermosetting compound (B) is a curable compound different from the first (meth)acrylate compound and the second (meth)acrylate compound.

[0127] Examples of the thermosetting compound having an epoxy group and a (meth)acryloyl group include glycidyl (meth)acrylate, allyl glycidyl ether, glycidyl ether of 4-hydroxybutyl (meth)acrylate, and cyclohexylmethyl 3,4-epoxy (meth)acrylate.

[0128] The thermosetting compound (B) preferably contains glycidyl (meth)acrylate or glycidyl ether of 4-hydroxybutyl (meth)acrylate, and more preferably contains glycidyl ether of 4-hydroxybutyl (meth)acrylate.

[0129] In 100% by weight of the curable composition, the content of the thermosetting compound (B) is preferably 4% by weight or more, more preferably 5% by weight or more, still more preferably 6% by weight or more, preferably 20% by weight or less, more preferably 18% by weight or less, and still more preferably 16% by weight or less. When the content of the thermosetting compound (B) is within the above lower limit and upper limit, the adhesion between the partition wall and the surface layer and the inkjet target portion can be improved, and discoloration can be more effectively suppressed when observing the LED module obliquely.

[0130] <Photopolymerization initiator (C)>

[0131] The curable composition contains a photopolymerization initiator (C).

[0132] Since the curable composition contains the photopolymerization initiator (C), the curable composition can be cured by irradiation with light.

[0133] Examples of the photopolymerization initiator (C) include a photo radical polymerization initiator and a photo cationic polymerization initiator. The photopolymerization initiator (C) is preferably a photo radical polymerization initiator. The photopolymerization initiator (C) may be used alone or in combination of two or more.

[0134] The photo radical polymerization initiator is a compound that generates radicals upon irradiation with light to initiate a radical polymerization reaction. Examples of the photo radical polymerization initiator include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; alkyl phenyl ketone compounds such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl acetophenone, and α-hydroxyalkyl phenyl ketone; acetophenone compounds such as acetophenone, aminobenzophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, aminobenzophenone compounds such as N,N-dimethylaminobenzophenone; anthraquinone compounds such as 2-methylanthraquinone, 2-ethylanthraquinone, and 2-tert-butylanthraquinone; thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; ketal compounds such as acetophenone dimethyl ketal and benzil dimethyl ketal; acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; oxime ester compounds such as 1,2-octanedione-1-[4-(phenylthio)-2-(o-benzoyl oxime)] and acetone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetyl oxime); titanocene compounds such as bis(cyclopentadienyl)-di-phenyl-titanium, bis(cyclopentadienyl)-dichloro-titanium, bis(cyclopentadienyl)-bis(2,3,4,5,6-pentafluorophenyl)titanium, and bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyrrol-1-yl)phenyl)titanium, etc. The photo radical polymerization initiator may be used alone or in combination of two or more.

[0135] From the viewpoints of improving the curability of the curable composition and more effectively suppressing color change when observing the LED module obliquely, the photopolymerization initiator (C) preferably contains an aminobenzophenone compound.

[0136] A photo-polymerization initiator assistant may also be used together with the photo-radical polymerization initiator. Examples of the photo-polymerization initiator assistant include ethyl N,N-dimethylaminobenzoate, isopentyl N,N-dimethylaminobenzoate, pentyl 4-dimethylaminobenzoate, triethylamine, and triethanolamine. Only one kind of the photo-polymerization initiator assistant may be used, or two or more kinds may be used in combination.

[0137] In addition, a titanocene compound such as CGI-784 (manufactured by Ciba Specialty Chemicals) having absorption in the visible light region may be used to promote the photo reaction.

[0138] Examples of the photo cationic polymerization initiator include sulfonium salts, iodine salts, metallocene compounds, and benzoin tosylate. Only one kind of the photo cationic polymerization initiator may be used, or two or more kinds may be used in combination.

[0139] In 100% by weight of the curable composition, the content of the photo-polymerization initiator (C) is preferably 4% by weight or more, more preferably 5% by weight or more, preferably 15% by weight or less, and more preferably 12% by weight or less. When the content of the photo-polymerization initiator (C) is within the range of not less than the lower limit and not more than the upper limit, the curability of the curable composition can be improved, and thus discoloration can be more effectively suppressed when the LED module is observed obliquely.

[0140] Relative to 100 parts by weight of the photo-curable compound (A), the content of the photo-polymerization initiator (C) is preferably 4 parts by weight or more, more preferably 5 parts by weight or more, preferably 20 parts by weight or less, and more preferably 15 parts by weight or less. When the content of the photo-polymerization initiator (C) is within the range of not less than the lower limit and not more than the upper limit, the curability of the curable composition can be improved, and thus discoloration can be more effectively suppressed when the LED module is observed obliquely.

[0141] <Thermal curing agent (D)>

[0142] The curable composition contains a thermal curing agent (D).

[0143] Since the curable composition contains the thermal curing agent (D), the curability of the curable composition (thermally curable compound (B)) can be improved.

[0144] Examples of the thermal curing agent (D) include organic acids, amine compounds, amide compounds, hydrazide compounds, imidazole compounds, imidazoline compounds, phenol compounds, urea compounds, polysulfide compounds, and acid anhydrides. Only one kind of the thermal curing agent (D) may be used, or two or more kinds may be used in combination.

[0145] Examples of the amine compound include aliphatic polyamines, alicyclic polyamines, aromatic polyamines, hydrazides, and guanidine derivatives. The amine compound may be a modified polyamine compound such as an amine-epoxy adduct. The amine compound may be an adduct of the amine compound. Examples of the adduct of the amine compound include an epoxy compound-added polyamine (a reaction product of an epoxy compound and a polyamine), a Michael-added polyamine (a reaction product of an α,β-unsaturated ketone and a polyamine), a Mannich-added polyamine (a condensate of a polyamine, formalin, and phenol), a thiourea-added polyamine (a reaction product of thiourea and a polyamine), and a ketone-capped polyamine (a reaction product of a ketone compound and a polyamine (ketimine)).

[0146] Examples of the aliphatic polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and diethylaminopropylamine.

[0147] Examples of the alicyclic polyamine include menthene diamine, isophorone diamine, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane adduct, bis(4-amino-3-methylcyclohexyl)methane, and bis(4-aminocyclohexyl)methane.

[0148] Examples of the aromatic polyamine include m-phenylenediamine, p-phenylenediamine, o-xylenediamine, m-xylenediamine, p-xylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyl diphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodicyclohexane, bis(4-aminophenyl)phenylmethane, 1,5-diaminonaphthalene, 1,1-bis(4-aminophenyl)cyclohexane, 2,2-bis[(4-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]sulfone, 1,3-bis(4-aminophenoxy)benzene, 4,4'-methylene-bis(2-chloroaniline), and 4,4'-diaminodiphenyl sulfone.

[0149] Examples of the hydrazide include carbodihydrazide, adipic dihydrazide, sebacic dihydrazide, dodecanedioic dihydrazide, and isophthalic dihydrazide.

[0150] Examples of the guanidine derivative include dicyandiamide, 1-o-tolylbiguanide, α-2,5-dimethylguanidine, α,ω-diphenyl diguanide, α,α-bis(amidino)guanidino diphenyl ether, p-chlorophenyl diguanide, α,α-hexamethylene bis[ω-(p-chlorophenol)] diguanide, phenylbiguanide oxalate, acetylguanidine, and diethyl cyanoacetylguanidine.

[0151] Examples of the phenolic compound include polyphenolic compounds. Examples of the polyphenolic compound include phenol, cresol, ethylphenol, butylphenol, octylphenol, bisphenol A, tetrabromobisphenol A, bisphenol F, bisphenol S, 4,4'-biphenylphenol, phenol novolak resin containing a naphthalene skeleton, phenol novolak resin containing a xylylene skeleton, phenol novolak resin containing a dicyclopentadiene skeleton, and phenol novolak resin containing a fluorene skeleton.

[0152] Examples of the acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, dodecylsuccinic anhydride, chlorendic anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, methylcyclohexene tetracarboxylic dianhydride, trimellitic anhydride, and polyazelic anhydride.

[0153] In 100% by weight of the curable composition, the content of the thermal curing agent (D) is preferably 1% by weight or more, more preferably 2% by weight or more, preferably 10% by weight or less, and more preferably 8% by weight or less. When the content of the thermal curing agent (D) is within the above lower limit and upper limit, the curability of the curable composition can be improved, and thus discoloration can be more effectively suppressed when observing the LED module obliquely.

[0154] With respect to 100 parts by weight of the thermosetting compound (B), the content of the thermal curing agent (D) is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, further preferably 25 parts by weight or more, particularly preferably 30 parts by weight or more, preferably 60 parts by weight or less, more preferably 55 parts by weight or less, and further preferably 50 parts by weight or less. When the content of the thermal curing agent (D) is within the above lower limit and upper limit, the curability of the curable composition can be improved, and thus discoloration can be more effectively suppressed when observing the LED module obliquely.

[0155] <Colorant (E)>

[0156] The curable composition contains a colorant (E).

[0157] The colorant (E) contains carbon black. Since the colorant (E) contains carbon black, it is possible to conceal the wiring disposed between the LED chips (improve wiring concealment), and discoloration can be suppressed when observing the LED module obliquely. The carbon black is a black inorganic pigment.

[0158] The average particle diameter of the carbon black is 40 nm or more and 100 nm or less. In the curable composition of the present invention, since the average particle diameter of the carbon black is 40 nm or more, it is easy to scatter transmitted light with a long wavelength, and the b* value can be easily adjusted to a smaller value (for example, 3 or less), and color change when observing the LED module obliquely can be suppressed. In the curable composition of the present invention, since the average particle diameter of the carbon black is 100 nm or less, it is easy to scatter transmitted light with a short wavelength, and the b* value can be easily adjusted to a larger value (for example, -3 or more), and color change when observing the LED module obliquely can be suppressed. In addition, in the curable composition of the present invention, since the average particle diameter of the carbon black is 40 nm or more and 100 nm or less, inkjet ejection property can be improved. From the viewpoint of further improving the inkjet ejection property and further suppressing color change when observing the LED module obliquely, the average particle diameter of the carbon black is preferably 45 nm or more, more preferably 50 nm or more, further preferably 60 nm or more, preferably 95 nm or less, more preferably 90 nm or less, and further preferably 80 nm or less.

[0159] The average particle diameter of the carbon black is preferably the average primary particle diameter. The average particle diameter of the carbon black is preferably measured by an arithmetic average particle diameter (D50) of the carbon black using an electron microscope.

[0160] Only one kind of the carbon black may be used, or two or more kinds of carbon blacks having different average particle diameters may be used in combination. It should be noted that when the curable composition (colorant (E)) contains two or more kinds of carbon blacks having different average particle diameters, the average particle diameter of the carbon black as a whole in the curable composition is preferably 40 nm or more and 100 nm or less.

[0161] The colorant (E) may further contain a colorant other than carbon black, or may not contain it. From the viewpoint of further improving wiring concealment and further suppressing color change when observing the LED module obliquely, the colorant (E) preferably further contains a colorant other than carbon black. It should be noted that from the viewpoint of easily adjusting the b* value to a preferred range, when the content of the carbon black exceeds 2.0% by weight in 100% by weight of the curable composition, the colorant (E) preferably does not contain a colorant other than carbon black.

[0162] Examples of the colorant other than the carbon black include dyes and pigments. Only one kind of the colorant other than the carbon black may be used, or two or more kinds may be used in combination.

[0163] Examples of the dye include pyrazole azo dyes, aniline azo dyes, triphenylmethane dyes, anthraquinone dyes, anthrapyridone dyes, benzylidene dyes, oxazole dyes, pyrazolotriazole azo dyes, pyridone azo dyes, cyanine dyes, phenothiazine dyes, pyrrolopyrazole azomethine dyes, xanthene dyes, phthalocyanine dyes, benzopyran dyes, indigo dyes, pyrromethene dyes, triarylmethane dyes, azomethine dyes, such as dyes, perinone dyes, quaterrylene dyes, and quinophthalone dyes. The dye may be an acid dye, a direct dye, a basic dye, a mordant dye, an acid mordant dye, an azo dye, a disperse dye, an oil-soluble dye, a food dye, and a dye obtained by mixing two or more of their derivatives to form black. The dye may be used alone or in combination of two or more.

[0164] The pigment may be an organic pigment or an inorganic pigment. The organic pigment may be an organic pigment having a metal atom or an organic pigment not having a metal atom. The pigment may be used alone or in combination of two or more.

[0165] Examples of the organic pigment include phthalocyanine compounds, quinacridone compounds, azo compounds, dibenzophenanthrene compounds, compounds, indole compounds, and di azine compounds, etc.

[0166] Examples of the phthalocyanine compound include copper phthalocyanine compounds, etc.

[0167] Examples of the inorganic pigment include carbon nanotubes, graphene, iron oxide, zinc oxide, titanium oxide, calcium carbonate, aluminum oxide, kaolin, calcium silicate, magnesium oxide, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, talc, feldspar powder, mica, barite, barium carbonate, silicon dioxide, and glass beads, etc.

[0168] From the viewpoint of further better suppressing color change when observing the LED module obliquely, the colorant other than carbon black preferably contains a blue dye. From the viewpoint of further better suppressing color change when observing the LED module obliquely, the colorant other than carbon black preferably contains an anthraquinone dye or a phthalocyanine compound, more preferably a phthalocyanine compound. From the viewpoint of better suppressing color change when observing the LED module obliquely, the colorant preferably further contains an anthraquinone dye or a phthalocyanine compound, more preferably further contains a phthalocyanine compound.

[0169] In 100% by weight of the curable composition, the content of the colorant (E) is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 5.0% by weight or less, more preferably 4.0% by weight or less, further preferably 2.0% by weight or less, and particularly preferably 1.5% by weight or less. When the content of the colorant (E) is not less than the lower limit and not more than the upper limit, the wiring concealability can be further improved, and the color change when observing the LED module obliquely can be further suppressed.

[0170] In 100% by weight of the curable composition, the content of the carbon black is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 5.0% by weight or less, more preferably 4.0% by weight or less, further preferably 3.0% by weight or less, particularly preferably 2.0% by weight or less, and most preferably 1.5% by weight or less. When the content of the carbon black is not less than the lower limit and not more than the upper limit, the wiring concealability can be further improved, and the curability is good. It should be noted that when the colorant (E) contains two or more types of carbon black having different average particle diameters, the content of the carbon black is the content of the whole carbon black.

[0171] From the viewpoint of further improving the wiring concealability and having good curability, in 100% by weight of the colorant (E), the content of the carbon black is preferably 90% by weight or more, more preferably 95% by weight or more, preferably 100% by weight or less, and more preferably 99% by weight or less.

[0172] From the viewpoint of suppressing the color change when observing the LED module obliquely well, in 100% by weight of the colorant (E), the content of the phthalocyanine compound is preferably 5% by weight or more, more preferably 10% by weight or more, preferably 20% by weight or less, and more preferably 15% by weight or less. When the content of the phthalocyanine compound is not less than the lower limit, the b* value can be further reduced. If the content of the phthalocyanine compound is not more than the upper limit, the b* value can be further increased.

[0173] <Dispersant (F)>

[0174] The curable composition contains a dispersant (F).

[0175] Since the curable composition contains the dispersant (F), the inkjet ejectability can be improved, and in addition, the color change when observing the obtained LED module obliquely can be suppressed.

[0176] Examples of the dispersant (F) include polyurethane dispersants, phosphate ester dispersants, carboxylic acid dispersants, amine dispersants, polyester dispersants, alkyl ammonium salt dispersants, castor oil acid ester dispersants, and the like. Only one kind of the dispersant (F) may be used, or two or more kinds may be used in combination.

[0177] Examples of the polyurethane dispersants include basic polyurethanes, polyurethane-acrylics, polyurethane-pureas, polyester-polyurethanes, polyether-polyurethanes, and polysiloxane polyurethanes.

[0178] Examples of the phosphate ester dispersants include polyoxyalkylene alkyl phenyl ether phosphates such as polyoxyethylene nonyl phenyl ether phosphate, polyoxyethylene tridecyl ether phosphate, and polyoxyethylene octyl phenyl ether phosphate, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl ether phosphate monoethanolamine salts, polyoxyethylene lauryl ether phosphate, polyoxyethylene lauryl ether phosphate monoethanolamine salts, polyvinyl styrenated phenyl ether phosphate, sodium alkyl phosphate, and alkyl phosphate monoethanolamine salts.

[0179] The carboxylic acid dispersant is preferably a polycarboxylic acid. Examples of the polycarboxylic acid include polycarboxylic acid polymers in which polyoxyalkylene is grafted onto a polymer having a carboxyl group in the main chain skeleton.

[0180] The weight average molecular weight of the polycarboxylic acid is preferably 500 or more, more preferably 1000 or more, further preferably 2000 or more, preferably 1500000 or less, more preferably 1250000 or less, and further preferably 1000000 or less. The weight average molecular weight represents the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0181] Examples of the amine dispersants include tetradecylamine acetate, laurylamine, oleylamine, distearylamine, and dimethyllaurylamine.

[0182] Examples of commercially available polyester dispersants include "Hinoact T-6000" manufactured by Kawaken Fine Chemicals Co., Ltd., "ANTI-TERRA-U / U100" manufactured by BYK Co., Ltd., and "BYK-2152" manufactured by BYK Co., Ltd.

[0183] Examples of commercially available alkyl ammonium salt dispersants include "BYK-9076" manufactured by BYK Co., Ltd., "BYK-140" manufactured by BYK Co., Ltd., and "BYK-180" manufactured by BYK Co., Ltd.

[0184] Examples of the castor oil acid ester dispersants include glycerol monoricinoleate, polyglycerol monoricinoleate, and acetyl ricinoleate.

[0185] From the viewpoint of more effectively suppressing discoloration when observing the LED module obliquely, the dispersant (F) preferably contains an alkylammonium salt dispersant or a phosphate ester dispersant, and more preferably contains a phosphate ester dispersant.

[0186] The acid value of the dispersant (F) is preferably 0 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably 20 mgKOH / g or more, preferably 150 mgKOH / g or less, more preferably 130 mgKOH / g or less, and still more preferably 110 mgKOH / g or less. When the acid value of the dispersant (F) is not less than the lower limit and not more than the upper limit, the dispersant protects the surface of the carbon black and can suppress thickening and carbon black aggregation caused by the reaction of polar groups present on the surface of the carbon black with the photocurable compound (A) or the thermosetting compound (B). As a result, inkjet ejection performance can be improved, and in addition, discoloration can be suppressed when observing the LED module obliquely.

[0187] The amine value of the dispersant (F) is preferably 0 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably 20 mgKOH / g or more, preferably 100 mgKOH / g or less, more preferably 90 mgKOH / g or less, and still more preferably 80 mgKOH / g or less. When the amine value of the dispersant (F) is not less than the lower limit and not more than the upper limit, the dispersant protects the surface of the carbon black and can suppress thickening and carbon black aggregation caused by the reaction of polar groups present on the surface of the carbon black with the photocurable compound (A) or the thermosetting compound (B). As a result, inkjet ejection performance can be improved, and in addition, discoloration can be suppressed when observing the LED module obliquely.

[0188] From the viewpoint of improving inkjet ejection performance and suppressing discoloration when observing the LED module obliquely, it is preferred that the acid value of the dispersant (F) is 10 mgKOH / g or more and 150 mgKOH / g or less, and the amine value of the dispersant (F) is 10 mgKOH / g or more and 100 mgKOH / g or less.

[0189] It should be noted that the acid value of the dispersant (F) can be measured according to JIS K0070, and the amine value of the dispersant (F) can be measured according to JIS K7237.

[0190] In 100% by weight of the curable composition, the content of the dispersant (F) is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, still more preferably 0.08% by weight or more, preferably 5% by weight or less, more preferably 3% by weight or less, still more preferably 2% by weight or less. When the content of the dispersant (F) is not less than the lower limit and not more than the upper limit, the inkjet ejectability can be improved, and in addition, color change can be suppressed when the LED module is observed obliquely.

[0191] Based on 100 parts by weight in total of the photocurable compound (A) and the thermosetting compound (B), the content of the dispersant (F) is preferably 0.1 part by weight or more, more preferably 0.2 part by weight or more, still more preferably 0.5 part by weight or more, preferably 5 parts by weight or less, more preferably 4 parts by weight or less, still more preferably 3 parts by weight or less. When the content of the dispersant (F) is not less than the lower limit and not more than the upper limit, the inkjet ejectability can be improved, and in addition, color change can be suppressed when the LED module is observed obliquely.

[0192] Based on 100 parts by weight of the colorant (E), the content of the dispersant (F) is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, still more preferably 20 parts by weight or more, preferably 200 parts by weight or less, more preferably 170 parts by weight or less, still more preferably 150 parts by weight or less. When the content of the dispersant (F) is not less than the lower limit and not more than the upper limit, the inkjet ejectability can be improved, and in addition, color change can be suppressed when the LED module is observed obliquely.

[0193] Based on 100 parts by weight of the carbon black, the content of the dispersant (F) is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, still more preferably 20 parts by weight or more, preferably 200 parts by weight or less, more preferably 170 parts by weight or less, still more preferably 150 parts by weight or less. When the content of the dispersant (F) is not less than the lower limit and not more than the upper limit, the inkjet ejectability can be improved, and in addition, color change can be suppressed when the LED module is observed obliquely.

[0194] <Other components>

[0195] The curable composition may contain other components in addition to the photocurable compound (A), the thermosettable compound (B), the photoinitiator (C), the thermosetting agent (D), the colorant (E), and the dispersant (F). Examples of the other components include fillers, antioxidants, defoamers, coupling agents, curing accelerators, mold release agents, surface treatment agents, flame retardants, viscosity modifiers, dispersion aids, surface modifiers, plasticizers, antibacterial agents, antifungal agents, leveling agents, stabilizers, anti-sagging agents, and phosphors.

[0196] The curable composition may contain a (meth)acrylate compound (hereinafter sometimes referred to as "other (meth)acrylate compound") in addition to the photocurable compound (A) and the thermosettable compound (B).

[0197] The other (meth)acrylate compound may be a polyfunctional (meth)acrylate compound or a monofunctional (meth)acrylate compound.

[0198] Examples of the other (meth)acrylate compound include polypropylene glycol di(meth)acrylate. From the viewpoint of improving the adhesion between the partition wall and the surface layer and the inkjet target portion, the other (meth)acrylate compound preferably contains polypropylene glycol di(meth)acrylate. The polypropylene glycol di(meth)acrylate is preferably polypropylene glycol #700 diacrylate or polypropylene glycol #400 diacrylate, and more preferably polypropylene glycol #700 diacrylate.

[0199] In 100% by weight of the curable composition, the content of the other (meth)acrylate compound is preferably 10% by weight or more, more preferably 15% by weight or more, still more preferably 20% by weight or more, preferably 70% by weight or less, more preferably 60% by weight or less, and still more preferably 55% by weight or less. When the content of the other (meth)acrylate compound is within the above lower limit and upper limit, the adhesion between the partition wall and the surface layer and the inkjet target portion can be improved.

[0200] Relative to 100 parts by weight in total of the photocurable compound (A) and the thermosettable compound (B), the content of the other (meth)acrylate compound is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, still more preferably 20 parts by weight or more, preferably 60 parts by weight or less, more preferably 50 parts by weight or less, and still more preferably 40 parts by weight or less. If the content of the other (meth)acrylate compound is within the above lower limit and upper limit, even when the obtained LED module is stored or used at a high temperature, discoloration can be suppressed (heat resistance is improved), and the adhesion between the partition wall and the surface layer and the inkjet target portion can be improved.

[0201] In 100% by weight of the curable composition, the content of the (meth)acrylate compound represented by the formula (1) is preferably 10% by weight or more, more preferably 15% by weight or more, still more preferably 20% by weight or more, preferably 70% by weight or less, more preferably 60% by weight or less, still more preferably 55% by weight or less. When the content of the (meth)acrylate compound represented by the formula (1) is within the above lower limit and the above upper limit, even when the obtained LED module is stored or used at a high temperature, discoloration can be suppressed (heat resistance is improved), and the adhesion between the partition wall and the surface layer and the inkjet target portion can be improved.

[0202] Relative to 100 parts by weight in total of the photocurable compound (A) and the thermosetting compound (B), the content of the (meth)acrylate compound represented by the formula (1) is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, still more preferably 40 parts by weight or more. Relative to 100 parts by weight in total of the photocurable compound (A) and the thermosetting compound (B), the content of the (meth)acrylate compound represented by the formula (1) is preferably 90 parts by weight or less, more preferably 80 parts by weight or less, still more preferably 70 parts by weight or less. When the content of the (meth)acrylate compound represented by the formula (1) is within the above lower limit and the above upper limit, even when the obtained LED module is stored or used at a high temperature, discoloration can be suppressed (heat resistance is improved), and the adhesion between the partition wall and the surface layer and the inkjet target portion can be improved.

[0203] (LED Module and Method for Manufacturing LED Module)

[0204] The LED module of the present invention includes: a substrate; an LED chip disposed on a first surface of the substrate; and a partition wall disposed on the first surface of the substrate. In the LED module of the present invention, the partition wall is disposed on the first surface of the substrate so as to surround the LED chip. In the LED module of the present invention, the partition wall is a cured product of the inkjet curable composition.

[0205] In addition, the method for manufacturing an LED module of the present invention includes the following steps. (1) A coating step of coating the inkjet curable composition on a first surface of a substrate by an inkjet method to form a composition layer. (2) A photocuring step of irradiating light on the coated inkjet curable composition to cure the inkjet curable composition to form a B-stage product. (3) A thermosetting step of thermosetting the inkjet curable B-stage product by heating to form a partition wall. (4) A step of disposing an LED chip on the first surface of the substrate and inside a region surrounded by the partition wall.

[0206] In the LED module and the method for manufacturing the LED module of the present invention, due to the above configuration, color change when observing the LED module obliquely can be suppressed.

[0207] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. It should be noted that in the following drawings, for the convenience of illustration, the size, thickness, shape, etc. are sometimes different from the actual size, thickness, shape, etc.

[0208] Figure 1 (a) is a plan view schematically showing an LED module (hereinafter, sometimes referred to as "first LED module") obtained by using the curable composition for inkjet of the first embodiment of the present invention. Figure 1 (b) is a cross-sectional view schematically showing the LED module.

[0209] Figure 1 The shown LED module 1 includes a substrate 11, an LED chip 12 disposed on the first surface 11a of the substrate 11, and a partition wall 13 disposed on the first surface 11a of the substrate 11. In the LED module 1, the partition wall 13 is disposed on the first surface 11a of the substrate 11 so as to surround the LED chip 12. In the LED module 1, the partition wall 13 is a cured product of the curable composition. In the LED module 1, the curable composition is used to form the partition wall 13. In the LED module 1, the curable composition is used as a curable composition for forming the partition wall. There is a space between the outer side surface of the LED chip 12 and the inner side surface of the partition wall 13. In the LED module 1, the partition wall 13 is formed of the curable composition. The partition wall 13 is not disposed (formed) on the surface of the LED chip 12. The upper surface of the LED chip 12 is not covered by the partition wall 13. The shape of the partition wall 13 is a frame shape.

[0210] Figure 3 (a) and (b), Figure 4 (c) and (d), Figure 5 (e) and (f) and Figure 6 (g) are cross-sectional views for explaining Figure 1 each process of the method for manufacturing the shown LED module.

[0211] First, as Figure 3 (a) shows, a curable composition is coated on the first surface 11a of the substrate 11 by an inkjet method to form a composition layer 13A (coating process). The curable composition is ejected from the ejection part 51 of the inkjet device.

[0212] Next, as Figure 3As shown in (b), light is irradiated from the light irradiation unit 52 of the inkjet device onto the composition layer 13A to cure the composition layer 13A, forming a B-stage product 13B (photo-curing step). The B-stage product 13B is a pre-cured product of the curable composition.

[0213] It should be noted that in the manufacturing method of the LED module, after coating the curable composition in a specific area, light can be irradiated onto the entire coated curable composition to form a B-stage product. In the manufacturing method of the LED module, each time multiple drops of the curable composition are coated, light can be irradiated onto the coated curable composition to form a B-stage product. In the manufacturing method of the LED module, each time 1 drop of the curable composition is coated, light can be irradiated onto the coated curable composition to form a B-stage product.

[0214] After the photo-curing step, it is determined whether to repeat the coating step and the photo-curing step. In the case of repeating the coating step and the photo-curing step, the curable composition is coated on the surface side of the formed B-stage product 13B opposite to the substrate 11 side.

[0215] Figure 4 (c) and Figure 4 (d) are diagrams showing the second coating step and the second photo-curing step respectively. As Figure 4 (c) shows, using an inkjet device, the curable composition is coated on the surface of the B-stage product 13B opposite to the substrate 11 side, and a composition layer 13A is formed on the surface of the B-stage product 13B. Then, as Figure 4 (d) shows, light is irradiated from the light irradiation unit 52 of the inkjet device onto the coated composition layer 13A to form a B-stage product 13B.

[0216] Figure 3 , Figure 4 In, the coating step and the photo-curing step are performed in the thickness direction of the composition layer Figure 3 (a) and Figure 3 (b) and Figure 4 (c) and Figure 4 (d) twice. By performing the coating step and the photo-curing step multiple times in the thickness direction of the composition layer respectively, the thickness of the B-stage product can be increased, and the aspect ratio (thickness / width) of the B-stage product can be increased. The coating step and the photo-curing step can be performed more than 2 times respectively, or can be performed more than 3 times.

[0217] By repeating the coating step and the photo-curing step, a Figure 5 frame-shaped B-stage product 13B as shown in (e) is formed.

[0218] Then, as Figure 5As shown in (f), the B-stage compound 13B is thermally cured by heating (thermal curing process). By heating Figure 5 the structure including the substrate 11 and the B-stage compound 13B obtained in (e), the B-stage compound 13B is thermally cured. Thereby, the partition wall 13 is formed. The partition wall 13 is a cured product layer of the curable composition.

[0219] Next, as Figure 6 shown in (g), the LED chip 12 is disposed inside the region surrounded by the partition wall 13 on the first surface 11a of the substrate 11. In this way, the Figure 1 LED module 1 shown can be obtained.

[0220] The curable composition is preferably ejected in a state heated to 40°C or higher and 100°C or lower when ejected by the inkjet device. From the viewpoint of continuously ejecting the curable composition for a long time, it is preferable to perform coating while circulating the curable composition.

[0221] When the curable composition is circulated while being heated, the temperature of the curable composition can be adjusted by introducing a heater into the ink tank of the inkjet device or using a heater in the circulation flow path portion.

[0222] In the photocuring process, it is preferable to irradiate ultraviolet rays. The illuminance and irradiation time of the ultraviolet rays in the photocuring process can be appropriately changed according to the composition of the curable composition and the coating thickness of the curable composition. The illuminance of the ultraviolet rays in the photocuring process can be, for example, 1000 mW / cm 2 or more, can be 5000 mW / cm 2 or more, can be 10000 mW / cm 2 or less, can be 8000 mW / cm 2 or less. The irradiation time of the ultraviolet rays in the photocuring process can be, for example, 0.01 second or more, can be 0.1 second or more, can be 400 seconds or less, can be 100 seconds or less.

[0223] The time from after the coating process to the irradiation of ultraviolet rays can be appropriately changed according to the composition of the curable composition (especially the types of the photocurable compound and the thermocurable compound) and the coating thickness. The time from after the coating process to the irradiation of ultraviolet rays can be 0.001 second or more, can be 0.01 second or more, can be 0.1 second or more, can be within 40 seconds, can be within 4 seconds, or can be within 0.4 second. The time from after the coating process to the irradiation of ultraviolet rays can be adjusted by the ejection speed of the inkjet device and the distance between the ejection portion and the light irradiation portion of the inkjet device.

[0224] The heating temperature and heating time in the thermosetting process can be appropriately changed according to the composition of the curable composition and the thickness of the B-stage product. The heating temperature in the thermosetting process can be, for example, 100 °C or higher, 120 °C or higher, 250 °C or lower, and 200 °C or lower. The heating time in the thermosetting process can be, for example, 5 minutes or longer, 30 minutes or longer, 600 minutes or shorter, and 300 minutes or shorter.

[0225] In the first LED module, it is preferable that the partition wall is arranged in a frame shape. In the first LED module, it is preferable that the partition wall is not arranged at the central part of the substrate. From the viewpoint of improving the brightness of the LED module, in the first LED module, it is preferable that a space is provided between the outer side surface of the LED chip and the inner side surface of the partition wall.

[0226] The width, height, etc. of the partition wall can be appropriately changed.

[0227] The width of the partition wall can be 30 μm or more, 50 μm or more, 70 μm or more, 1000 μm or less, 800 μm or less, and 700 μm or less.

[0228] From the viewpoint of further improving the light extraction efficiency of the light generated from the LED chip, the height of the LED chip is preferably 10 μm or more, more preferably 20 μm or more, further preferably 50 μm or more, preferably 300 μm or less, more preferably 200 μm or less, and further preferably 150 μm or less.

[0229] From the viewpoint of further improving the light extraction efficiency of the light generated from the LED chip, the height of the partition wall is preferably 10 μm or more, more preferably 20 μm or more, further preferably 30 μm or more, preferably 200 μm or less, more preferably 150 μm or less, and further preferably 100 μm or less.

[0230] From the viewpoint of further improving the light extraction efficiency of the light generated from the LED chip, the height of the partition wall is preferably 50 μm or more lower than the height of the LED chip, more preferably 60 μm or more lower, and further preferably 70 μm or more lower.

[0231] The aspect ratio (height to width ratio (height / width)) of the partition wall is preferably 5 or more, more preferably 8 or more, and further preferably 10 or more. The aspect ratio (height to width ratio (height / width)) of the partition wall can be 100 or less, 50 or less, 25 or less, and 15 or less.

[0232] From the viewpoint of further improving the light extraction efficiency of the light generated from the LED chip, the first LED module preferably further includes a reflective film on the inner wall surface of the partition wall. The reflective film may be formed on the outer wall surface of the partition wall or may not be formed.

[0233] From the viewpoint of further improving the light extraction efficiency of the light generated from the LED chip, the method for manufacturing the LED module preferably further includes a step of forming a reflective film on the inner wall surface of the partition wall.

[0234] Examples of the material of the reflective film include silver, chromium, copper, titanium, and aluminum. The material of the reflective film may use only one kind or may use two or more kinds in combination. From the viewpoint of further improving the utilization efficiency of the light generated by the LED chip, the material of the reflective film is preferably titanium or aluminum.

[0235] Examples of the method for forming the reflective film on the inner wall surface of the partition wall include a method using electroless plating, a method using electroplating, a method using physical impact, a method using mechanochemical reaction, a physical film-forming method, or a method using physical adsorption, and a method of coating a metal powder or a paste containing a metal powder and an adhesive on the surface of the partition wall. The method for forming the reflective film on the inner wall surface of the partition wall is preferably a method using electroless plating, electroplating, or physical impact. Examples of the physical film-forming method include methods such as vacuum evaporation, ion plating, and ion sputtering. In addition, as the method based on the physical impact, THETA COMPOSER (manufactured by Tokushu Kikou Co., Ltd.) can be used.

[0236] Figure 2 It is a cross-sectional view schematically showing an LED module (hereinafter, sometimes referred to as "second LED module") obtained by using the curable composition for inkjet of the second embodiment of the present invention.

[0237] Figure 2 The shown LED module 1A includes a substrate 11, an LED chip 12 disposed on the first surface 11a of the substrate 11, a light-transmitting layer 16 disposed on the surface of the LED chip 12 and the first surface 11a of the substrate 11, and a surface layer 15 disposed on the surface of the light-transmitting layer 16. In the LED module 1A, the surface layer 15 is a cured product of the curable composition. In the LED module 1A, the curable composition is used to form the surface layer 15. In the LED module 1A, the curable composition is used as a curable composition for forming the surface layer.

[0238] In the LED module 1A, the light-transmitting layer 16 is disposed on the upper surface and the side surface of the LED chip 12. The light-transmitting layer 16 is in contact with the LED chip 12. Specifically, the light-transmitting layer 16 is in contact with the upper surface and the side surface of the LED chip 12.

[0239] In the LED module 1A, the surface layer 15 is disposed on the surface of the light-transmitting layer 16. The surface layer 15 is in contact with the light-transmitting layer 16. Specifically, the surface layer 15 is in contact with the upper surface of the light-transmitting layer 16. The surface layer 15 covers the light-transmitting layer 16. The surface layer 15 is disposed above the LED chip 12. The surface layer 15 is not in contact with the LED chip 12. The surface layer 15 is a colored layer.

[0240] In the second LED module, other layers may also exist between the surface layer (colored layer) and the light-transmitting layer. In the second LED module, the surface layer may cover the entire upper surface of the light-transmitting layer or only a part of the upper surface.

[0241] In the second LED module, the thickness of the surface layer disposed above the light-transmitting layer is preferably 1.0 μm or more, more preferably 3.0 μm or more, further preferably 5.0 μm or more, preferably 50 μm or less, more preferably 30 μm or less, and further preferably 10 μm or less. If the thickness of the surface layer disposed above the light-transmitting layer is at least the lower limit, discoloration can be more effectively suppressed when observing the LED module obliquely, and the wiring concealment can be improved. If the thickness of the surface layer disposed above the light-transmitting layer is at most the upper limit, the brightness can be further improved.

[0242] In the second LED module, the thickness of the light-transmitting layer is not particularly limited. The thickness of the light-transmitting layer is preferably higher than the height of the LED chip.

[0243] In the first LED module and the second LED module, the substrate may be a transparent member or may not be a transparent member. Examples of the substrate include a circuit board and a silicon substrate.

[0244] In the first LED module and the second LED module, the LED chip may be a red LED chip, a blue LED chip, a green LED chip, a UV-LED chip, or a combination of these LED chips. The UV-LED chip may be a deep ultraviolet UV-LED chip.

[0245] The shapes of the first LED module and the second LED module are not particularly limited. The shapes of the first LED module and the second LED module may be circular, rectangular, or triangular.

[0246] Hereinafter, examples and comparative examples will be given to specifically illustrate the present invention. The present invention is not limited to the following examples.

[0247] Prepare the following materials.

[0248] Photocurable compound (A):

[0249] Tricyclodecane dimethanol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., “A-DCP”, glass transition temperature of the homopolymer: 190 °C)

[0250] Ethoxylated cyclohexane methanol diacrylate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., “HBPE-4”, glass transition temperature of the homopolymer: 50 °C)

[0251] 1,9-Nonanediol diacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., “Viscoat #260”, glass transition temperature of the homopolymer: 68 °C)

[0252] 1,6-Hexanediol diacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., “Viscoat #230”, glass transition temperature of the homopolymer: 63 °C)

[0253] Propylene oxide-modified bisphenol A diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., “LIGHT ACRYLATE BP-4PA”, glass transition temperature of the homopolymer: 80 °C)

[0254] Ethylene oxide-added 1,6-hexanediol diacrylate (manufactured by Toyo Chemical Co., Ltd., “Miramer M202”)

[0255] Ethylene oxide-added trimethylolpropane triacrylate (manufactured by BASF SE, “Laromer LR8863”, glass transition temperature of the homopolymer: 110 °C)

[0256] Thermosetting compound (B):

[0257] 4-Hydroxybutyl acrylate glycidyl ether (manufactured by Mitsubishi Chemical Corporation, “4HBAGE”, cyclic ether group (glycidyl group))

[0258] Bisphenol F type epoxy compound (manufactured by Mitsubishi Chemical Corporation, “EXA-830”, cyclic ether group (epoxy group))

[0259] Other (meth)acrylate compounds:

[0260] 3-Methoxybutyl acrylate

[0261] 2-Hydroxy-3-phenoxypropyl acrylate (manufactured by Toagosei Co., Ltd., “ARONIX M5700”)

[0262] Photoinitiator (C):

[0263] 2-(Dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (“Onmirad 379” manufactured by IGM)

[0264] 2,4,6-Trimethylbenzoyl diphenylphosphine oxide (“Omnirad TPO” manufactured by IGM Resins)

[0265] 2-Benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (“Omnirad 369” manufactured by IGM)

[0266] Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (“Omnirad 819” manufactured by IGM)

[0267] Thermosetting agent (D):

[0268] Bis[4-(3-aminophenoxy)phenyl]sulfone (“BAPS-M” manufactured by SEIKA)

[0269] 4,4’-Diamino-3,3’-diethyl-5,5’-dimethyldiphenylmethane (“4,4’-Diamino-3,3’-dimethyldiphenylmethane” manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0270] Colorant (E):

[0271] Carbon black #10 (manufactured by Mitsubishi Chemical Corporation, average primary particle size: 75 nm)

[0272] Carbon black #20 (manufactured by Mitsubishi Chemical Corporation, average primary particle size: 50 nm)

[0273] Carbon black #25 (manufactured by Mitsubishi Chemical Corporation, average primary particle size: 47 nm)

[0274] Carbon black MA220 (manufactured by Mitsubishi Chemical Corporation, average primary particle size: 55 nm)

[0275] Carbon black #960 (manufactured by Mitsubishi Chemical Corporation, average primary particle size: 20 nm)

[0276] Carbon black MA600 (manufactured by Mitsubishi Chemical Corporation, average primary particle size: 20 nm)

[0277] Carbon black SeastTA (manufactured by TOKAI CARBON, average primary particle size: 122 nm)

[0278] OPLAS BLUE 635 (manufactured by Orient Chemical Industries, anthraquinone dye)

[0279] Oil Blue 5511-N (manufactured by Yuki Gosei Kogyo Co., Ltd., phthalocyanine compound)

[0280] Copper(II) phthalocyanine tetrasulfonic acid tetrasodium salt (manufactured by Fujifilm Wako Pure Chemical Corporation, phthalocyanine sulfonate (phthalocyanine compound))

[0281] Dispersant (F):

[0282] Alkylammonium salt dispersant ("BYK-9076" manufactured by BYK, acid value: 38 mg KOH / g, amine value: 44 mg KOH / g)

[0283] Phosphate ester dispersant ("BYK-106" manufactured by BYK, acid value: 132 mg KOH / g, amine value: 74 mg KOH / g)

[0284] Amine dispersant ("DISPERBYK-180" manufactured by BYK, acid value: 94 mg KOH / g, amine value: 94 mg KOH / g)

[0285] Alkylammonium salt dispersant ("DISPERBYK-145" manufactured by BYK, acid value: 76 mg KOH / g, amine value: 71 mg KOH / g)

[0286] Carboxylic acid dispersant ("DISPERBYK-108" manufactured by BYK, acid value: 0 mg KOH / g, amine value: 71 mg KOH / g)

[0287] Phosphate ester dispersant ("DISPERBYK-111" manufactured by BYK, acid value: 129 mg KOH / g, amine value: 0 mg KOH / g)

[0288] Basic polymer dispersant ("Ajisper PB821" manufactured by AJINOMOTO FINE-TECHNO Co., acid value: 10 mg KOH / g, amine value: 17 mg KOH / g)

[0289] Polymerization inhibitor:

[0290] Aluminum N-nitroso-N-phenylhydroxylamine ("Q1301" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0291] Antioxidant:

[0292] Phenolic antioxidant ("AO-80" manufactured by ADEKA)

[0293] Phosphite antioxidant ("PEP-36" manufactured by ADEKA)

[0294] (Examples 1 to 15 and Comparative Examples 1 to 4)

[0295] The following components were blended in the blending amounts shown in Tables 1 to 10 below to obtain a curable composition for inkjet (curable composition).

[0296] (Evaluation)

[0297] (1) Inkjet ejectability

[0298] An ejection test of the curable composition was carried out from the inkjet head of a piezoelectric inkjet printer equipped with an ultraviolet irradiation device, and the judgment was made according to the following criteria. Note that the inkjet head temperature was set at 50°C.

[0299] [Judgment criteria for inkjet ejectability]

[0300] ○○: The curable composition can be continuously ejected from the inkjet head for 10 hours or more;

[0301] ○: The curable composition can be continuously ejected from the inkjet head for 10 hours or more, but ejection unevenness slightly occurs during the 10-hour continuous ejection;

[0302] ×: The curable composition cannot be ejected at the initial stage of ejection from the inkjet head, or the curable composition can be continuously ejected from the inkjet head, but cannot be continuously ejected for 10 hours or more.

[0303] (2) b* value of the cured product

[0304] On the surface of a glass substrate (thickness 0.7 mm), a cured product (thickness 30 μm) of the obtained curable composition was formed by the above method. Using a spectrocolorimeter ("CM-26dG" manufactured by Konica Minolta), the reflected light of the cured product was measured, and the b* value in the L*a*b* color system was obtained.

[0305] (3) Color change when observing the LED module obliquely

[0306] A glass substrate (thickness 30 μm) having a plurality of electrodes, wirings, and a plurality of LED chips (height 100 μm) on the upper surface was prepared. The obtained curable composition was coated by inkjet in the gaps between the LED chips, and the cumulative light amount was irradiated at 1000 mJ / cm 2 so that the illuminance at a wavelength of 365 nm became 1000 mW / cm 2The ultraviolet rays (UV-LED) cure it to form partition walls (thickness: 30 μm), obtaining an LED module. Using a spectrophotometer colorimeter (Konica Minolta Inc.'s "CM-26dG"), white light is irradiated from the LED chip in accordance with JIS Z8781-4:2013. At this time, the L*, a*, and b* values in the L*a*b* color system are obtained for the light measured directly above the LED chip and the light measured at a position 70° from the upper surface of the LED chip with the glass substrate tilted. The color difference ΔE*ab is calculated from the obtained L*, a*, and b* values. Based on the obtained color difference ΔE*ab, the discoloration when observing the LED module obliquely is determined according to the following criteria.

[0307] [Criteria for Determining Discoloration when Observing the LED Module Obliquely]

[0308] ○○: Color difference ΔE*ab is less than 1

[0309] ○: Color difference ΔE*ab is 1 or more and less than 2

[0310] △: Color difference ΔE*ab is 2 or more and 7 or less

[0311] ×: Color difference ΔE*ab exceeds 7

[0312] (4) Discoloration when storing the cured product at high temperature (heat resistance)

[0313] For the cured product obtained in (2), using a spectrophotometer colorimeter (Konica Minolta Inc.'s "CM-26dG"), the L*, a*, and b* values in the L*a*b* color system are obtained for the reflected light when light (wavelength: 300 nm to 800 nm) is irradiated from the upper surface of the cured product. In addition, the cured product is stored at 100°C for 240 hours, and for the stored cured product, the L*, a*, and b* values are similarly obtained. The color difference ΔE*ab of the cured product before and after storage is calculated from the obtained L*, a*, and b* values. The discoloration when storing the cured product at high temperature is determined according to the following criteria.

[0314] [Criteria for Determining Discoloration when Storing the Cured Product at High Temperature]

[0315] ○: Color difference ΔE*ab is less than 5

[0316] ×: Color difference ΔE*ab is 5 or more

[0317] The composition and results of the curable composition are shown in Tables 1 to 10 below. It should be noted that the composition of the curable composition is described in two tables for each example (or each comparative example) (for example, the composition of the curable composition of Example 1 is described in Tables 1 and 2).

[0318] [Table 1]

[0319]

[0320] [Table 2]

[0321]

[0322] [Table 3]

[0323]

[0324] [Table 4]

[0325]

[0326] [Table 5]

[0327]

[0328] [Table 6]

[0329]

[0330] [Table 7]

[0331]

[0332] [Table 8]

[0333]

[0334] [Table 9]

[0335]

[0336] [Table 10]

[0337]

[0338] Symbol Explanation

[0339] 1, 1A… LED module

[0340] 11… Substrate

[0341] 12… LED chip

[0342] 13… Partition wall

[0343] 13A… Composition layer

[0344] 13B… B-stage compound

[0345] 15… Surface layer

[0346] 16… Light transmission layer

[0347] 51… Ejection part

[0348] 52…Light irradiation unit

Claims

1. A curable composition for inkjet, comprising: A photocurable compound having two or more photopolymerizable functional groups and having no cyclic ether group, Thermosetting compounds having a cyclic ether group, Photopolymerization initiator, Thermal curing agent, Colorants, and Dispersants, wherein The colorant comprises carbon black, The average particle size of the carbon black is greater than or equal to 40 nm and less than or equal to 100 nm. When a cured product of the curable composition for inkjet having a thickness of 30 μm is irradiated with light, a b* value of reflected light of the cured product in the L*a*b* colorimetric system is not less than −3 and not more than 3.

2. The curable composition for inkjet according to claim 1, wherein The acid value of the dispersant is 10 mgKOH / g or more and 150 mgKOH / g or less, and the amine value of the dispersant is 10 mgKOH / g or more and 100 mgKOH / g or less.

3. The curable composition for inkjet according to claim 1 or 2, wherein The photopolymerization initiator includes an aminoacetophenone compound.

4. The curable composition for inkjet according to any one of claims 1 to 3, wherein The content of the carbon black in 100% by weight of the curable composition for inkjet is 0.1% by weight or more and 5.0% by weight or less.

5. The curable composition for inkjet according to any one of claims 1 to 4, wherein The colorant may include colorants other than carbon black.

6. The curable composition for inkjet according to any one of claims 1 to 5, wherein The colorant further includes a phthalocyanine compound.

7. The curable composition for inkjet according to any one of claims 1 to 6, wherein The photocurable compound includes a photocurable compound having two or more (meth)acryloyl groups and a dicyclopentadiene skeleton.

8. The curable composition for inkjet according to any one of claims 1 to 7, wherein The heat curable compound includes 4-hydroxybutyl (meth)acrylate glycidyl ether. 9 . The curable composition for inkjet according to claim 1 , which is used for forming partition walls in an LED module.

10. An LED module comprising: substrate; An LED chip is disposed on the first surface of the substrate; and a partition wall disposed on the first surface of the substrate, The partition wall is arranged on the first surface of the substrate in a manner of surrounding the LED chip. The partition wall is a cured product of the curable composition for inkjet according to any one of claims 1 to 9.

11. A method for manufacturing an LED module, comprising: A coating step of coating the curable inkjet composition according to any one of claims 1 to 9 on the first surface of the substrate by inkjet method to form a composition layer; a photocuring step of irradiating the applied curable composition for inkjet with light to cure the curable composition for inkjet to form a B-stage product; A thermal curing step, in which the B-stage compound is thermally cured by heating to form a partition wall; as well as and placing an LED chip on the first surface of the substrate and inside a region surrounded by the partition wall.

Images