JP7511399B2 - Curable resin composition, dry film, cured product, electronic parts - Google Patents

Description

The present invention relates to a curable resin composition, a dry film, a cured product, an electronic component, a light-emitting electronic component, and a method for producing the light-emitting electronic component.

In recent years, electronic devices such as smartphones and smart watches have become more sophisticated, and functional sensors using optical sensor modules as proximity sensors, pulse wave sensors, etc. have been built in. The optical sensor module for these applications is a combination of a light-emitting element and a detector (light-receiving element) in one module. A partition wall provided between the light-emitting element and the detector is made of a material that has light-shielding properties to prevent light from the light-emitting element from directly reaching the detector. To achieve this light-shielding properties, a resin containing carbon black is used for the partition wall.
Furthermore, Patent Document 1 discloses a resin containing 5 ppm or more of carbon black as a resin composition for a light-shielding portion of a lighting device.

JP 2018-107041 A

However, when carbon black is blended into a resin composition to obtain sufficient light-blocking properties, the carbon black tends to aggregate, has poor dispersibility, and can settle within the resin, resulting in poor long-term stability and a fading color over time.

The object of the present invention is to provide a curable resin composition, a dry film, a cured product, and an electronic component that have sufficient light-shielding properties and excellent carbon black dispersibility and sedimentation suppression properties.

It was also thought that the curable resin composition of the present invention could be used, for example, as an encapsulant for concealing light-emitting elements in a display. However, this was not suitable for use in concealing light-emitting elements while covering them.

Therefore, another object of the present invention is to provide a light-emitting electronic component having a light-emitting element that effectively utilizes the properties of the curable resin composition, and a method for manufacturing the light-emitting electronic component.

The inventors conducted extensive research to solve the above problems, and discovered that a curable resin composition containing a polymer resin with a glass transition point of 20°C or less and a weight average molecular weight of 10,000 or more, an epoxy resin, and carbon black, but no inorganic filler, improves the dispersibility of carbon black, has excellent sedimentation suppression properties, and has sufficient light blocking properties, thereby completing the present invention. In addition, the inventors discovered that a cured product of the curable resin composition is suitable for use in preventing light leakage by being interposed between multiple light-emitting elements, that is, as a light diffusion prevention layer, thereby completing another aspect of the present invention.

That is, the curable resin composition of the present invention is a curable resin composition that contains a polymer resin with a glass transition point of 20°C or less and a weight average molecular weight of 10,000 or more, an epoxy resin, and carbon black, but does not contain an inorganic filler, and is characterized in that the cured film obtained by heating at 100°C for 30 minutes and at 200°C for 60 minutes has a transmittance of less than 0.5% at a film thickness of 40 μm for light wavelengths of 400 nm to 800 nm.

The curable resin composition of the present invention preferably further contains at least one of a compound having a phenolic hydroxyl group, a compound having an active ester group, a compound having a cyanate ester group, and a compound having a maleimide group as a curing agent.

The curable resin composition of the present invention is preferably used as a light diffusion prevention layer interposed between multiple light emitting elements.

The dry film of the present invention is characterized by having a resin layer obtained by applying the curable resin composition to a film and drying it.

The cured product of the present invention is characterized by being obtained by curing the curable resin composition or the resin layer of the dry film.

The electronic component of the present invention is characterized by having the above-mentioned cured product.

The light-emitting electronic component of the present invention is characterized by having a substrate having a plurality of light-emitting elements, a light diffusion prevention layer made of the cured product interposed between the plurality of light-emitting elements, and a sealant formed on the plurality of light-emitting elements and the light diffusion prevention layer.

The method for producing a light-emitting electronic component of the present invention includes the steps of:
(A) forming a light diffusion prevention layer made of the curable resin composition or the dry film on a substrate having a plurality of light emitting elements so as to cover the plurality of light emitting elements;
(B) thermally curing the light diffusion preventing layer;
(C) etching the heat-cured light diffusion prevention layer to remove or thin the light diffusion prevention layer on the light emitting elements;
(D1) is characterized by including a step of forming an encapsulant having a transmittance (transmittance at light wavelengths of 400 nm to 800 nm through a cured film having a thickness of 50 μm) of 85% or more on the plurality of light-emitting elements and the light diffusion preventing layer after the step (C).

Another method for producing a light-emitting electronic component according to the present invention includes the steps of:
(A) forming a light diffusion prevention layer made of the curable resin composition or the dry film on a substrate having a plurality of light emitting elements so as to cover the plurality of light emitting elements;
(B) thermally curing the light diffusion preventing layer;
(C) etching the heat-cured light diffusion prevention layer to remove or thin the light diffusion prevention layer on the light emitting elements;
(D2) The method is characterized by including a step of forming an encapsulant having a haze of 10% or less after curing on the plurality of light-emitting elements and the light-diffusion preventing layer after the step (C).

According to the present invention, it is possible to provide a resin composition containing carbon black with excellent light-shielding properties, a curable resin composition that has excellent dispersibility and suppression of sedimentation of carbon black and has sufficient light-shielding properties, a dry film, a cured product, an electronic component, and further a light-emitting electronic component having a light-emitting element that effectively utilizes the properties of the curable resin composition, and a method for manufacturing the light-emitting electronic component.

1 is a schematic diagram of an optical sensor module in which the curable resin composition of the present invention is used. 1 is a schematic diagram of a light-emitting electronic component in which the curable resin composition of the present invention is used. 1 is a schematic diagram of a method for manufacturing a light-emitting electronic component of the present invention. 1 is a diagram showing the color of a colorant on the coordinate axes of a* and b* values in the L*a*b* color system.

The curable resin composition, the dry film, the cured product, the electronic component, the light-emitting electronic component, and the method for producing the light-emitting electronic component of the present invention will be described in more detail below.
<Curable resin composition>
The curable resin composition of the present invention is a curable resin composition that contains a polymer resin having a glass transition point of 20° C. or lower and a weight average molecular weight of 10,000 or more, an epoxy resin, and carbon black, but does not contain an inorganic filler, and is characterized in that a cured film obtained by heating at 100° C. for 30 minutes and at 200° C. for 60 minutes has a transmittance of less than 0.5% at a film thickness of 40 μm for light wavelengths of 400 nm to 800 nm.
By including a polymer resin having a glass transition point of 20° C. or less and a weight average molecular weight of 10,000 or more, the curable resin composition can suppress the structure of the carbon black from becoming large, and can improve the dispersibility and suppress sedimentation of the carbon black. Therefore, even if a sufficient amount of carbon black is included to obtain a black cured product that blocks light from a light-emitting element, such as a partition between a light-emitting element and a detector in an optical sensor module or a light diffusion prevention layer interposed between a plurality of light-emitting elements in a display, the carbon black can be dispersed in the resin composition while suppressing aggregation. Furthermore, by not including an inorganic filler, a cured product having sufficient light-shielding properties with a transmittance of less than 0.5% (film thickness: 40 μm) can be obtained.
Furthermore, by containing a polymer resin having a glass transition point of 20°C or lower and a weight average molecular weight of 10,000 or more, the curable resin composition can reduce warping of the entire substrate when a cured product is formed on the substrate in the form of a dry film or the like.
Each component of the curable resin composition will be described below.

[Polymer resin having a glass transition temperature of 20° C. or lower and a weight average molecular weight of 10,000 or more]
The glass transition temperature of a polymer resin having a glass transition point of 20° C. or less and a weight average molecular weight of 10,000 or more is preferably −40 to 20° C., more preferably −15 to 15° C., and particularly preferably −5 to 15° C. If it is −5 to 15° C., warping of the cured product can be effectively suppressed. The glass transition temperature of the polymer resin is a value measured using a differential scanning calorimeter (DSC8500, manufactured by PerkinElmer).
In addition, since the higher the weight average molecular weight of the polymer resin, the greater the effect of preventing carbon black from settling, the weight average molecular weight is preferably 100,000 or more, and more preferably 200,000 or more. The upper limit is, for example, 1,000,000 or less, and preferably 500,000 or less.

Examples of polymer resins include polymer resins having one or more skeletons selected from a butadiene skeleton, an amide skeleton, an imide skeleton, an acetal skeleton, a carbonate skeleton, an ester skeleton, a urethane skeleton, an acrylic skeleton, and a siloxane skeleton. Examples include polymer resins having an acrylic skeleton (manufactured by Nagase ChemteX Corporation, such as "SG-P3", "SG-600LB", "SG-280", "SG-790", "SG-K2", "SG-70L", "SG-708-6", "WS-023 EK30", "SG-80H", and "SG-600TEA"; manufactured by Negami Chemical Industries, Ltd., "SN-50", "AS-3000E", and "ME-2000").

From the viewpoint of flatness of the cured product, the polymer resin is preferably an acrylic copolymer having a glass transition point of 20°C or less and a weight average molecular weight of 10,000 or more. Also, from the viewpoint of improving the dispersibility of carbon black and suppressing sedimentation of the composition, it is preferable that the polymer resin be an acrylic copolymer having a glass transition point of 20°C or less and a weight average molecular weight of 100,000 to 1,000,000, and more preferably an acrylic copolymer having a glass transition point of -5 to 15°C and a weight average molecular weight of 200,000 to 500,000.

The acrylic copolymer may have a functional group, such as a carboxyl group, a hydroxyl group, an epoxy group, or an amide group.

The acrylic copolymer preferably contains an epoxy group, and more preferably contains an epoxy group and an amide group. By containing an epoxy group, warping of the cured product can be suppressed.

The polymer resins can be used alone or in combination of two or more. The amount of the polymer resin is preferably 0.5 to 30% by mass, based on the total solid content of the composition, more preferably 5.0 to 25% by mass, and even more preferably 10 to 25% by mass, particularly from the viewpoint of dispersibility and suppression of sedimentation of the composition.

In this specification, the weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC) (polystyrene standard) using the following measuring device and measuring conditions.
Measuring device: Waters 2695
Detector: Waters 2414, RI (differential refractometer)
Column: Waters "HSPgel Column, HR MB-L, 3 μm, 6 mm × 150 mm" × 2 + Waters "HSPgel Column, HR1, 3 μm, 6 mm × 150 mm" × 2
Measurement condition:
Column temperature: 40°C
RI detector set temperature: 35°C
Developing solvent: tetrahydrofuran Flow rate: 0.5 mL/min Sample volume: 10 μL
Sample concentration: 0.7% by mass

[Epoxy resin]
The epoxy resin is a resin having an epoxy group, and any of those known in the art can be used. Examples include bifunctional epoxy resins having two epoxy groups in a molecule, and polyfunctional epoxy resins having three or more epoxy groups in a molecule. The epoxy resin may be hydrogenated. The epoxy resin may include at least one of solid epoxy resins and liquid epoxy resins. The solid epoxy resin and liquid epoxy resin may be used alone or in combination of two or more. The epoxy resin may also include semi-solid epoxy resins and crystallized epoxy resins. In this specification, solid epoxy resins refer to epoxy resins that are solid at 40°C, semi-solid epoxy resins refer to epoxy resins that are solid at 20°C and liquid at 40°C, and liquid epoxy resins refer to epoxy resins that are liquid at 20°C. The liquid state is determined in accordance with the "Method of Confirming Liquid State" in Appendix 2 of the Ministerial Ordinance on the Testing and Properties of Hazardous Materials (Ministry of Home Affairs Ordinance No. 1 of 1989). For example, the method described in JP 2016-079384 A, paragraphs 23 to 25 is used. The crystalline epoxy resin means a highly crystalline epoxy resin, and is a thermosetting epoxy resin in which polymer chains are regularly arranged at a temperature below the melting point, and which, although being a solid resin, has a low viscosity comparable to that of a liquid resin when melted.

The semi-solid epoxy resin preferably contains at least one selected from the group consisting of bisphenol A type epoxy resin, naphthalene type epoxy resin, and phenol novolac type epoxy resin. By containing the semi-solid epoxy resin, the glass transition temperature (Tg) of the cured product is high, the CTE is low, and the crack resistance is excellent.
Examples of semi-solid epoxy resins include bisphenol A type epoxy resins such as EPICLON 860, EPICLON 900-IM, EPICLON EXA-4816, and EPICLON EXA-4822 manufactured by DIC Corporation, Epotohto YD-134 manufactured by Nippon Steel Chemical & Material Co., Ltd., jER834 and jER872 manufactured by Mitsubishi Chemical Corporation, and ELA-134 manufactured by Sumitomo Chemical Co., Ltd.; naphthalene type epoxy resins such as EPICLON HP-4032 manufactured by DIC Corporation; and phenol novolac type epoxy resins such as EPICLON N-740 manufactured by DIC Corporation.

As the crystalline epoxy resin, for example, a crystalline epoxy resin having a biphenyl structure, a sulfide structure, a phenylene structure, a naphthalene structure, etc. can be used. Biphenyl type epoxy resins are available, for example, as jER YX4000, jER YX4000H, jER YL6121H, jER YL6640, and jER YL6677 manufactured by Mitsubishi Chemical Corporation. Diphenyl sulfide type epoxy resins are available, for example, as Epotohto YSLV-120TE manufactured by Nippon Steel Chemical & Material Co., Ltd. Phenylene type epoxy resins are available, for example, as Epotohto YDC-1312 manufactured by Nippon Steel Chemical & Material Co., Ltd. Naphthalene type epoxy resins are available, for example, as EPICLON HP-4032, EPICLON HP-4032D, and EPICLON HP-4700 manufactured by DIC Corporation. In addition, crystalline epoxy resins that can be used include Epotohto YSLV-90C manufactured by Nippon Steel Chemical & Materials Co., Ltd. and TEPIC-S (triglycidyl isocyanurate) manufactured by Nissan Chemical Industries, Ltd.

Examples of solid epoxy resins include naphthalene-type epoxy resins such as EPICLON HP-4700 (naphthalene-type epoxy resin) manufactured by DIC Corporation, EXA4700 (tetrafunctional naphthalene-type epoxy resin) manufactured by DIC Corporation, and NC-7000 (naphthalene skeleton-containing multifunctional solid epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; epoxidized products of condensation products of phenols and aromatic aldehydes having a phenolic hydroxyl group (trisphenol-type epoxy resins) such as EPPN-502H (trisphenol epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; EPICLON manufactured by DIC Corporation Examples of epoxy resins include dicyclopentadiene aralkyl type epoxy resins such as HP-7200H (dicyclopentadiene skeleton-containing polyfunctional solid epoxy resin); biphenyl aralkyl type epoxy resins such as NC-3000H (biphenyl skeleton-containing polyfunctional solid epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; biphenyl/phenol novolac type epoxy resins such as NC-3000L manufactured by Nippon Kayaku Co., Ltd.; novolac type epoxy resins such as EPICLON N660, N690, N770 manufactured by DIC Corporation and EOCN-104S manufactured by Nippon Kayaku Co., Ltd.; phosphorus-containing epoxy resins such as TX0712 manufactured by Nippon Steel Chemical & Material Co., Ltd.; tris(2,3-epoxypropyl)isocyanurate such as TEPIC manufactured by Nissan Chemical Co., Ltd., etc. By including a solid epoxy resin, the glass transition temperature of the cured product is increased and the heat resistance is excellent.

Examples of liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, glycidylamine type epoxy resins, aminophenol type epoxy resins, alicyclic epoxy resins, etc. By including liquid epoxy resins, the dry film has excellent flexibility.

The amount of epoxy resin blended is preferably 10 to 75% by mass based on the total solid content of the composition. If it is within this range, the cured product will have excellent heat resistance, flexibility, and crack resistance.

The curable resin composition of the present invention may contain curable resin components other than epoxy resins, as long as the effects of the present invention are not impaired. For example, known and commonly used thermosetting resins such as isocyanate compounds, blocked isocyanate compounds, amino resins, benzoxazine resins, carbodiimide resins, cyclocarbonate compounds, polyfunctional oxetane compounds, and episulfide resins can be used.

[Carbon black]
Carbon black can obtain light-shielding properties by dispersing it in a resin. Carbon black generally used as a black colorant can be used. As the carbon black, one or more types of known carbon black such as channel black, furnace black, thermal black, and lamp black can be used. Resin-coated carbon black may also be used. Furthermore, carbon nanofibers and carbon nanotubes may also be used.
When carbon black is blended into the resin composition, carbon black powder or a carbon black dispersion may be added.
The particle size of the carbon black is preferably 10 to 500 nm, more preferably 10 to 300 nm, and particularly preferably 10 to 100 nm. The particle size refers to the average particle size, and can be determined by a measuring device using the dynamic light scattering method. An example of a measuring device using the dynamic light scattering method is NanotracWave II UT151 manufactured by Microtrac Bell.
The amount of carbon black is preferably 0.1 to 15% by mass based on the total solid content of the curable resin composition, and more preferably 1.0 to 15% by mass from the viewpoint of transmittance. When the amount of carbon black is 0.1% by mass or more, sufficient light blocking properties are obtained, and when it is 15% by mass or less, the occurrence of cracks can be suppressed. The more the amount of carbon black is increased, the more likely the carbon black is to settle, but in the curable resin composition of the present invention, the settling of carbon black is suppressed by including the above-mentioned polymer resin having a glass transition point of 20° C. or less and a weight average molecular weight of 10,000 or more.

[Inorganic filler]
The curable resin composition of the present invention does not contain any inorganic filler other than carbon black. Examples of conventionally known inorganic fillers include barium sulfate, barium titanate, silica such as amorphous silica, crystalline silica, fused silica, and spherical silica, talc, clay, Neuburg silica particles, boehmite, magnesium carbonate, calcium carbonate, titanium oxide, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, and calcium zirconate, and other extender pigments, and metal powders such as copper, tin, zinc, nickel, silver, palladium, aluminum, iron, cobalt, gold, and platinum. However, when these inorganic fillers are contained in the curable resin composition, when light is applied to the cured product of the curable resin composition, the inorganic filler diffuses the light, resulting in a decrease in light-shielding properties. Therefore, the curable resin composition of the present invention does not contain any inorganic filler other than carbon black.

[Curing agent]
The curable resin composition preferably contains a curing agent. Examples of the curing agent include a compound having a phenolic hydroxyl group, a polycarboxylic acid and its acid anhydride, dicyandiamide, a compound having a cyanate ester group, a compound having an active ester group, a compound having a maleimide group, an alicyclic olefin polymer, and a compound having a thiol group. The curing agent can be used alone or in combination of two or more.

In the present invention, the curable resin composition preferably contains at least one of a compound having a phenolic hydroxyl group, a compound having an active ester group, a compound having a cyanate ester group, and a compound having a maleimide group. By using a compound having a phenolic hydroxyl group and a compound having an active ester group, a cured product having excellent adhesion to low roughness substrates and circuits can be obtained. In addition, by using a cyanate ester, the Tg of the cured product is increased and heat resistance is improved, and by using a compound having a maleimide group, the Tg of the cured product is increased and heat resistance is improved, and the CTE can be reduced.

Examples of the compound having a phenolic hydroxyl group include conventionally known compounds such as phenol novolak resins, alkylphenol novolak resins, bisphenol A novolak resins, dicyclopentadiene-type phenolic resins, Xylok-type phenolic resins, terpene-modified phenolic resins, cresol/naphthol resins, polyvinyl phenols, phenol/naphthol resins, α-naphthol skeleton-containing phenolic resins, triazine skeleton-containing cresol novolak resins, biphenylaralkyl-type phenolic resins, and Xylok-type phenolic novolak resins.
Among the compounds having a phenolic hydroxyl group, those having a hydroxyl group equivalent of 100 g/eq. or more are preferred. Examples of compounds having a phenolic hydroxyl group with a hydroxyl group equivalent of 100 g/eq. or more include dicyclopentadiene skeleton phenol novolac resin (GDP series, manufactured by Gun-ei Chemical Industry Co., Ltd.), Zylok type phenol novolac resin (MEH-7800, manufactured by Meiwa Kasei Co., Ltd.), biphenyl aralkyl type novolac resin (MEH-7851, manufactured by Meiwa Kasei Co., Ltd.), naphthol aralkyl type curing agent (SN series, manufactured by Nippon Steel Chemical & Material Co., Ltd.), triazine skeleton-containing cresol novolac resin (LA-3018-50P, manufactured by DIC Corporation), and triazine skeleton-containing phenol novolac resin (LA-705N, manufactured by DIC Corporation).

The compound having a cyanate ester group is preferably a compound having two or more cyanate ester groups (-OCN) in one molecule. Any conventionally known compound having a cyanate ester group can be used. Examples of compounds having a cyanate ester group include phenol novolac type cyanate ester resin, alkylphenol novolac type cyanate ester resin, dicyclopentadiene type cyanate ester resin, bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, and bisphenol S type cyanate ester resin. In addition, it may be a prepolymer in which a part is triazine-converted.

Commercially available compounds having a cyanate ester group include phenol novolac type multifunctional cyanate ester resin (PT30S, manufactured by Lonza Japan), a prepolymer in which part or all of bisphenol A dicyanate is triazine-converted to form a trimer (BA230S75, manufactured by Lonza Japan), and a cyanate ester resin containing a dicyclopentadiene structure (DT-4000, DT-7000, manufactured by Lonza Japan).

The compound having an active ester group is preferably a compound having two or more active ester groups in one molecule. A compound having an active ester group can generally be obtained by a condensation reaction between a carboxylic acid compound and a hydroxy compound. Among them, a compound having an active ester group obtained by using a phenol compound or a naphthol compound as the hydroxy compound is preferable. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadienyl diphenol, and phenol novolac. Additionally, compounds having an active ester group may be of the naphthalene diol alkyl/benzoic acid type.

Commercially available compounds having an active ester group include dicyclopentadiene-type diphenol compounds, such as HPC8000-65T (manufactured by DIC Corporation), HPC8100-65T (manufactured by DIC Corporation), and HPC8150-65T (manufactured by DIC Corporation).

The compound having a maleimide group is a compound having a maleimide skeleton, and any of the conventionally known compounds can be used. The compound having a maleimide group preferably has two or more maleimide skeletons, and examples thereof include N,N'-1,3-phenylene dimaleimide, N,N'-1,4-phenylene dimaleimide, N,N'-4,4-diphenylmethane bismaleimide, 1,2-bis(maleimide)ethane, 1,6-bismaleimide hexane, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, 2,2'-bis-[4-(4-maleimide phenoxy)phenyl]propionate, and the like. More preferably, the oligomer is at least one of the following: bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, bisphenol A diphenyl ether bismaleimide, polyphenylmethane maleimide, and oligomers thereof, as well as diamine condensates having a maleimide skeleton. The oligomer is an oligomer obtained by condensing a compound having a maleimide group, which is a monomer among the above-mentioned compounds having a maleimide group.

Commercially available compounds having maleimide groups include BMI-1000 (4,4'-diphenylmethane bismaleimide, manufactured by Daiwa Chemical Industry Co., Ltd.), BMI-2300 (phenylmethane bismaleimide, manufactured by Daiwa Chemical Industry Co., Ltd.), BMI-3000 (m-phenylene bismaleimide, manufactured by Daiwa Chemical Industry Co., Ltd.), BMI-5100 (3,3'-dimethyl-5,5'-dimethyl-4,4'-diphenylmethane bismaleimide, manufactured by Daiwa Chemical Industry Co., Ltd.), BMI-7000 (4-methyl-1,3,-phenylene bismaleimide, manufactured by Daiwa Chemical Industry Co., Ltd.), and BMI-TMH ((1,6-bismaleimide-2,2,4-trimethyl)hexane, manufactured by Daiwa Chemical Industry Co., Ltd.).

Examples of the acid anhydride include alicyclic dibasic acid anhydrides such as methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, and tetrabromophthalic anhydride; aliphatic or aromatic dibasic acid anhydrides such as succinic anhydride, maleic anhydride, itaconic anhydride, octenylsuccinic anhydride, pentadodecenylsuccinic anhydride, phthalic anhydride, and trimellitic anhydride; and aliphatic or aromatic tetrabasic acid dianhydrides such as biphenyltetracarboxylic dianhydride, diphenylethertetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride.

The compound having a thiol group is a compound having two or more thiol groups in one molecule. Any conventionally known compound having a thiol group can be used. Examples of compounds having a thiol group include TMMP; trimethylolpropane tris(3-mercaptopropionate), PEMP; pentaerythritol tetrakis(3-mercaptopropionate), DPMP; dipentaerythritol hexaneth(3-mercaptopropionate), etc.

The amount of hardener to be used can be adjusted as appropriate depending on the type, but for example, it is preferably 20 to 500 parts by weight per 100 parts by weight of epoxy resin.

In the following, as an example, we will explain the components that may be included in addition to the above components when forming a curable resin composition using a thermosetting resin composition that does not contain a photocurable component.

The curable resin composition may further contain a thermoplastic resin in order to improve the mechanical strength of the resulting cured film. The thermoplastic resin is preferably soluble in a solvent. When the thermoplastic resin is soluble in a solvent, the flexibility of the dry film is improved, and the occurrence of cracks and powdering can be suppressed. Examples of the thermoplastic resin include thermoplastic polyhydroxypolyether resins, phenoxy resins which are condensates of epichlorohydrin and various bifunctional phenolic compounds, or phenoxy resins in which the hydroxyl groups of the hydroxyether moiety present in the skeleton are esterified using various acid anhydrides or acid chlorides, polyvinyl acetal resins, polyamide resins, polyamideimide resins, block copolymers, and the like. The thermoplastic resins may be used alone or in combination of two or more.

Specific examples of phenoxy resins include FX280 and FX293 manufactured by Nippon Steel Chemical & Material Co., Ltd., and YX8100, YX6954, YL6954, and YL6974 manufactured by Mitsubishi Chemical Corporation. Specific examples of polyvinyl acetal resins include the S-LEC KS series manufactured by Sekisui Chemical Co., Ltd., polyamide resins include the KS5000 series manufactured by Hitachi Chemical Co., Ltd., and the BP series manufactured by Nippon Kayaku Co., Ltd., and polyamide-imide resins include the KS9000 series manufactured by Hitachi Chemical Co., Ltd.

The amount of thermoplastic resin is preferably 0.5 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content of the curable resin composition. When the amount of thermoplastic resin is within the above range, a uniform roughened surface condition is easily obtained.

Furthermore, the curable resin composition may contain rubber particles as necessary. Examples of such rubber particles include polybutadiene rubber, polyisopropylene rubber, urethane-modified polybutadiene rubber, epoxy-modified polybutadiene rubber, acrylonitrile-modified polybutadiene rubber, carboxyl-modified polybutadiene rubber, acrylonitrile-butadiene rubber modified with carboxyl or hydroxyl groups, and crosslinked rubber particles and core-shell type rubber particles thereof. One type may be used alone or two or more types may be used in combination. These rubber particles are added to improve the flexibility of the resulting cured film, improve crack resistance, enable surface roughening treatment with an oxidizing agent, and improve adhesion strength with copper foil, etc.

The average particle size of the rubber-like particles is preferably in the range of 0.005 to 1 μm, and more preferably in the range of 0.2 to 1 μm. The average particle size of the rubber-like particles in the present invention can be measured in the same manner as the particle size of the carbon black described above.

The amount of rubber particles is preferably 0.5 to 10% by mass, and more preferably 1 to 5% by mass, based on the total solid content of the curable resin composition. If it is 0.5% by mass or more, crack resistance is obtained and the adhesive strength with the conductor pattern, etc. can be improved. If it is 10% by mass or less, the coefficient of thermal expansion (CTE) decreases and the glass transition temperature (Tg) increases, improving the curing characteristics.

The curable resin composition may contain a curing accelerator. The curing accelerator accelerates the thermosetting reaction and is used to further improve properties such as adhesion, chemical resistance, and heat resistance. Specific examples of such curing accelerators include imidazole and its derivatives; guanamines such as acetoguanamine and benzoguanamine; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylylenediamine, diaminodiphenylsulfone, urea, urea derivatives, melamine, and polybasic hydrazides; organic acid salts and/or epoxy adducts thereof; amine complexes of boron trifluoride; triazine derivatives such as ethyldiamino-S-triazine, 2,4-diamino-S-triazine, and 2,4-diamino-6-xylyl-S-triazine; amines such as trimethylamine, triethanolamine, N,N-dimethyloctylamine, N-benzyldimethylamine, pyridine, N-methylmorpholine, hexa(N-methyl)melamine, 2,4,6-tris(dimethylaminophenol), tetramethylguanidine, and m-aminophenol; polyvinylphenol, polyvinylphenol brominated products, phenol novolac, alkyl amines, and alkyl amines. Examples of the curing accelerator include polyphenols such as phenylphenol novolak; organic phosphines such as tributylphosphine, triphenylphosphine, and tris-2-cyanoethylphosphine; phosphonium salts such as tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide and hexadecyltributylphosphonium chloride; quaternary ammonium salts such as benzyltrimethylammonium chloride and phenyltributylammonium chloride; the polybasic acid anhydrides; photocationic polymerization catalysts such as diphenyliodonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, and 2,4,6-triphenylthiopyrylium hexafluorophosphate; styrene-maleic anhydride resins; equimolar reactants of phenylisocyanate and dimethylamine, equimolar reactants of organic polyisocyanates such as tolylene diisocyanate and isophorone diisocyanate and dimethylamine, and metal catalysts. Among the curing accelerators, phosphonium salts are preferred because they provide BHAST resistance.

The curing accelerator can be used alone or in combination of two or more types. The use of a curing accelerator is not essential, but when it is particularly desired to accelerate curing, it can be used in the range of preferably 0.01 to 5 parts by mass per 100 parts by mass of epoxy resin. In the case of a metal catalyst, the amount is preferably 10 to 550 ppm, more preferably 25 to 200 ppm, calculated as metal per 100 parts by mass of the compound having a cyanate ester group.

The organic solvent is not particularly limited, but examples thereof include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum-based solvents. Specific examples include ketones such as methyl ethyl ketone, cyclohexanone, methyl butyl ketone, and methyl isobutyl ketone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, isobutyl acetate, ethylene glycol diethyl ether, and ethylene glycol diethyl ether. Examples of the solvent include esters such as propylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol butyl ether acetate; alcohols such as ethanol, propanol, 2-methoxypropanol, n-butanol, isobutyl alcohol, isopentyl alcohol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha, as well as N,N-dimethylformamide (DMF), tetrachloroethylene, and turpentine. In addition, organic solvents such as Swazol 1000 and Swazol 1500 manufactured by Maruzen Petrochemical Co., Ltd., Solvent #100 and Solvent #150 manufactured by Sankyo Chemical Co., Ltd., Shellsol A100 and Shellsol A150 manufactured by Shell Chemicals Japan Co., Ltd., and Ipzol 100 and Ipzol 150 manufactured by Idemitsu Kosan Co., Ltd. may be used. The organic solvent may be used alone or as a mixture of two or more kinds.

When made into a dry film, the amount of residual solvent in the resin layer made of the curable resin composition is preferably 0.5 to 7.0% by mass. If the residual solvent is 7.0% by mass or less, bumping during thermal curing is suppressed and the surface flatness is improved. In addition, the melt viscosity is prevented from dropping too low, causing the resin to flow, and the flatness is improved. If the residual solvent is 0.5% by mass or more, the flowability during lamination is good, and the flatness and embeddability are improved.

The curable resin composition may further contain, as necessary, conventionally known colorants such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, and naphthalene black; conventionally known thickeners such as asbestos, orben, bentone, and finely powdered silica; silicone-based, fluorine-based, and polymer-based defoamers and/or leveling agents; adhesion promoters such as thiazole-based, triazole-based, and silane coupling agents; flame retardants, titanate-based, and aluminum-based conventionally known additives.

<Applications>
The curable resin composition of the present invention has excellent light-shielding properties and excellent suppression of carbon black sedimentation, and therefore can be used for a partition provided between a light-emitting element and a detector in an optical sensor module. It can also be used for a light diffusion prevention layer interposed between a plurality of light-emitting elements (for example, between each of RGB light-emitting elements in a display using micro LEDs). The interposition mode is not particularly limited, but for example, it may be interposed in a state where it is directly sandwiched between the light-emitting elements. In addition, the light diffusion prevention layer may be disposed so as to surround the periphery of each light-emitting element and interposed between the light-emitting elements. It can also be used for a dry film.

Figure 1 shows a schematic diagram of an optical sensor module in which the curable resin composition of the present invention is used. The optical sensor module 1 in the figure includes a light-emitting element 2 and a detector 3 separated by a partition 4. The light-emitting element 2 emits light toward an object 5, and the light reflected from the object 5 is received by the detector 3. The partition 4 is required to be able to block light so that the light emitted from the light-emitting element 2 does not directly reach the detector 3. The curable resin composition of the present invention is suitable for this partition 4. However, the use of the curable resin composition is not limited to the partition 4.

Figure 2 shows a schematic diagram of a light-emitting electronic component 10 in which a light-diffusion prevention layer made of a cured product of the curable resin composition of the present invention is interposed between multiple light-emitting elements. The light-emitting electronic component 10 has a structure in which a light-diffusion prevention layer 16 is interposed between light-emitting elements 12, 13, and 14 on a substrate 11. The light-diffusion prevention layer can block light diffusion from the light-emitting elements, i.e., light leaking from the sides. This makes it possible to obtain a sharp image, for example, in display applications.

<Dry film>
The dry film of the present invention is not particularly limited as long as it has a resin layer obtained by applying the above-mentioned curable resin composition of the present invention to a film and drying it, and may be formed by laminating two or more resin layers of dry films to form a dry film having two or more resin layers. When forming a resin layer by application and drying, it is difficult to uniformly form a large resin layer, but by laminating resin layers to form a thick film, it is possible to easily form a uniform resin layer with a thick film. The thick resin layer functions as a light diffusion prevention layer by being interposed between light emitting elements even when the thickness of the light emitting element is large. A dry film generally includes a carrier film, a resin layer, and a protective film.

[Carrier film]
The carrier film has a role of supporting the resin layer of the dry film, and is a film to which a curable resin composition is applied when forming the resin layer. Examples of the carrier film include polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, polystyrene films, and other thermoplastic resin films, and surface-treated paper. Among these, polyester films can be preferably used from the viewpoints of heat resistance, mechanical strength, and ease of handling. The thickness of the carrier film is not particularly limited, but is appropriately selected in the range of approximately 10 to 150 μm depending on the application. The surface of the carrier film on which the resin layer is provided may be subjected to a release treatment. In addition, sputtering or ultra-thin copper foil may be formed on the surface of the carrier film on which the resin layer is provided.

[Protective film]
The protective film is provided on the opposite side of the resin layer to the carrier film in order to prevent dust and the like from adhering to the surface of the resin layer of the dry film and to improve handling. In the present invention, it is preferable to use a biaxially oriented polypropylene film as the protective film. By using a biaxially oriented polypropylene film, it is possible to reduce cooling shrinkage after lamination to the resin layer. However, the protective film is not limited to a biaxially oriented polypropylene film. The thickness of the protective film is not particularly limited, but is appropriately selected in the range of about 10 to 100 μm depending on the application. It is preferable that the surface of the protective film on which the resin layer is provided is subjected to a treatment for improving adhesion, such as embossing, corona treatment, or slight adhesion treatment, or a release treatment.

The thickness of the resin layer of the dry film is not particularly limited, and may be, for example, 1 to 200 μm. In the present invention, a larger thickness leads to better flatness, so a thickness of, for example, 30 μm or more, 50 μm or more, or even 100 μm or more may be suitably used. Note that multiple resin layers of the dry film of the present invention may be stacked together to form a resin layer with a thickness of more than 200 μm. In this case, a roll laminator or vacuum laminator may be used.

In addition to the optical sensor module described above, an electronic component using the cured product of the curable resin composition of the present invention or the cured product of the dry film of the present invention is, for example, a printed wiring board. A conventionally known method may be used as a method for manufacturing such a printed wiring board. For example, in the case of a dry film in which the resin layer is made of a thermosetting resin composition and the resin layer is sandwiched between a carrier film and a protective film, a printed wiring board can be manufactured by the following method. Either the carrier film or the protective film is peeled off from the dry film, and the dry film is heat-laminated to a circuit board on which a circuit pattern is formed, and then heat-cured. The heat curing may be performed in an oven or by hot plate pressing. When laminating or hot plate pressing the substrate on which a circuit is formed and the dry film of the present invention, copper foil or a substrate on which a circuit is formed can also be laminated at the same time. A printed wiring board can be manufactured by forming a pattern or a via hole by laser irradiation or a drill at a position corresponding to a predetermined position on the substrate on which a circuit pattern is formed, and exposing the circuit wiring. At this time, if there is a component (smear) that has not been completely removed and remains on the circuit wiring in the pattern or via hole, a desmear treatment is performed. The remaining carrier film or protective film can be peeled off after lamination, heat curing, laser processing, or desmearing. The interlayer circuit can also be connected using copper pillars.

<Light-emitting electronic components>
The light-emitting electronic component of the present invention is characterized by having a substrate having a plurality of light-emitting elements such as LED chips, a light-diffusion prevention layer made of a cured product of the curable resin composition of the present invention interposed between the plurality of light-emitting elements, and a sealant formed on the plurality of light-emitting elements and the light-diffusion prevention layer.

The encapsulant is not particularly limited and may be selected according to the purpose. For example, when brightness is to be increased, it is preferable that the encapsulant is transparent, and in a cured film having a thickness of 50 μm, the transmittance of all light wavelengths from 400 nm to 800 nm is preferably 85% or more. More preferably, it is 90% or more, and even more preferably, it is 93% or more. In addition, the haze of the cured film is preferably 10% or less, more preferably 5% or less, from the viewpoint of the balance between the hiding power and the light transmittance.

The thickness of the sealing material is preferably 50 μm or less, and more preferably 30 μm or less.

<Method of manufacturing light-emitting electronic components>
The curable resin composition of the present invention does not contain an inorganic filler and is easy to etch, so that the thickness of the light diffusion prevention layer is easy to adjust. Therefore, it can be suitably used for manufacturing a light-emitting electronic component having a laminated structure with an encapsulant on the light diffusion prevention layer. The manufacturing method of the light-emitting electronic component of the present invention includes the following steps (A), (B), (C), and (D1) or (D2).

(A) forming a light diffusion preventing layer made of the curable resin composition of the present invention or a resin layer of the dry film of the present invention on a substrate having a plurality of light emitting elements so as to cover the plurality of light emitting elements)
In step (A), a light diffusion prevention layer 15 made of the curable resin composition of the present invention or a resin layer of the dry film of the present invention may be formed on a substrate 11 having a plurality of light emitting elements (12, 13, 14) as shown in Fig. 3(a) so as to cover the light emitting elements as shown in Fig. 3(b). In this specification, the term "a plurality of light emitting elements" is not particularly limited as long as it is two or more light emitting elements. The light emitting color of the light emitting element is not particularly limited, and may be, for example, red, green, or blue.

The method for forming the light diffusion prevention layer is not particularly limited, and the layer may be formed by a known, commonly used method. For example, the light diffusion prevention layer may be formed by applying a curable resin composition and then drying the applied composition, or by laminating a dry film having a resin layer made of the curable resin composition.

(B) Step of Heat-Curing the Light Diffusion Prevention Layer)
In the step (B), the light diffusion preventing layer made of the curable resin composition of the present invention or the resin layer of the dry film of the present invention is thermally cured (FIG. 3(c)). The temperature for thermal curing is not particularly limited, but it is preferable to cure the light diffusion preventing layer under conditions of 100° C. for 30 minutes and then 200° C. for 60 minutes.

(C) A step of etching the heat-cured light diffusion prevention layer to remove or thin the light diffusion prevention layer on the light emitting element.
In the step (C), etching is performed (FIG. 3(d)), and the light diffusion prevention layer on the light emitting element is removed or thinned to the height of the light emitting element (FIG. 3(e)). By removing the light diffusion prevention layer to the height of the light emitting element, the brightness of the light emitting surface is increased and visibility during light emission is ensured. At this time, since it is technically difficult to completely remove the light diffusion prevention layer from the light emitting element, it is sufficient that the light diffusion prevention layer is substantially removed, and some thin film may remain. The etching may be physical etching such as plasma processing or chemical etching. The etching conditions may be, for example, dry etching using a mixed gas of CF ₄ /O ₂ /N ₂ in an anisotropic plasma device under the conditions of output 1500 to 3000 W and 180 to 600 seconds. At this time, the gas supply amount of CF ₄ may be, for example, 50 to 100 sccm, the gas supply amount of O ₂ may be, for example, 500 to 1000 sccm, and the gas supply amount of N ₂ may be, for example, 50 to 100 sccm.

(Step (D))
As shown in Fig. 3(f), the light-emitting element is covered with a sealant to manufacture a light-emitting electronic component. As the step (D), if it is desired to increase the brightness, the step (D1) may be performed, and if it is desired to conceal the light-emitting element, the step (D2) may be performed.

((D1) is a process for forming an encapsulant having a transmittance of 85% or more at light wavelengths of 400 nm to 800 nm in a cured film having a thickness of 50 μm on the plurality of light emitting elements and the light diffusion preventing layer after the process (C).)
In step (D1), an encapsulant having a transmittance of 85% or more (preferably 90% or more, more preferably 93% or more) at light wavelengths of 400 nm to 800 nm in a cured film having a thickness of 50 μm is formed on the light emitting element and the light diffusion preventing layer. Here, "in a cured film having a thickness of 50 μm" describes the conditions for measuring the transmittance, and does not specify the thickness of the encapsulant in step (D1). The method for forming the encapsulant is not particularly limited, and for example, the encapsulant composition may be applied, or may be formed by laminating it as a dry film.

The encapsulant composition that can produce a transparent cured product with a transmittance of 85% or more is not particularly limited, but an encapsulant composition (d1) containing an epoxy resin, an organic solvent, and dicyandiamide is preferred. According to the encapsulant composition (d1), in a resin film having a thickness of 50 μm formed by the encapsulant composition, the transmittance of all wavelengths of light from 400 nm to 800 nm is 75% or less, and in a cured film having a thickness of 50 μm formed by the encapsulant composition, the transmittance of all wavelengths of light from 400 nm to 800 nm can be 85% or more. Such properties are attributed to dicyandiamide, and even if the film becomes cloudy due to the inclusion of dicyandiamide before curing and has a low transmittance of the light wavelength, a transparent cured film with excellent transmittance can be obtained after thermal curing. In addition, compositions containing epoxy resins are easily colored by thermal curing, but the cured product of the encapsulant composition (d1) is less likely to be colored. Conventional transparent encapsulant compositions are transparent, so it is not easy to find defects during coating, and it is particularly difficult to find defects such as sink marks and craters when coating on a transparent film such as a PET film. Although it is possible to color the composition to make it easier to find defects during coating, such a colored encapsulant composition cannot function as a transparent encapsulant. For example, it is disadvantageous as an encapsulant for optical components or light-emitting components. Similarly, coloring of the transparent encapsulant composition due to thermal curing is also undesirable. According to the encapsulant composition (d1), the transmittance of the resin film before curing is low, so that defects during coating are easy to find, while the transmittance of the resin film after curing is high and the transparency is excellent, and coloring due to thermal curing is also suppressed.

In the sealing material composition (d1), the epoxy resin may be any of solid epoxy resin, semi-solid epoxy resin, liquid epoxy resin, and crystalline epoxy resin, and among them, it is preferable to contain a liquid epoxy resin from the viewpoint of slit processing of the dry film. Examples of the liquid epoxy resin include the same as those described above. In addition, among the epoxy resins, it is preferable to contain an epoxy resin having an alicyclic skeleton because coloring is further suppressed and a more transparent cured product can be obtained, and it is more preferable that the solid epoxy resin contains a solid epoxy resin having an alicyclic skeleton. The epoxy resin having an alicyclic skeleton may be, for example, a hydrogenated epoxy resin of an epoxy resin having an aromatic ring such as a bisphenol A type epoxy resin. Examples of the alicyclic skeleton include a cyclopentane ring, a dicyclopentane ring, and a cyclohexane ring. Examples of the epoxy resin having an alicyclic skeleton include ST-6100 manufactured by Nippon Steel Chemical & Material Co., Ltd. and YX8000 manufactured by Mitsubishi Chemical Corporation. The epoxy resin may be used alone or in combination of two or more types. In the encapsulant composition (d1), the amount of the epoxy resin is preferably 50 to 98 mass% of the total solid content of the composition. In addition, in the encapsulant composition (d1), the amount of the epoxy resin having an alicyclic skeleton is preferably 30 to 98 mass%, more preferably 35 to 98 mass%, of the total solid content of the composition.

In the sealant composition (d1), the organic solvent may be the same as those mentioned above, but it is preferable that the organic solvent does not contain an organic solvent that dissolves dicyandiamide, and it is desirable that the organic solvent does not contain an amide-based solvent such as DMF. The organic solvent preferably contains one or more of cyclohexanone, methyl ethyl ketone, and propylene glycol monomethyl ether acetate. The organic solvent may be used alone or as a mixture of two or more. In the sealant composition, the amount of the organic solvent is preferably 30 to 70 mass% of the composition.

In the sealing material composition (d1), the amount of dicyandiamide is preferably 1 to 5 mass % of the total solid content of the composition.

The encapsulant composition (d1) may contain a curing accelerator. Specific examples of the curing accelerator include those mentioned above, but imidazole and its derivatives; guanamines; polyamines; organic acid salts and/or epoxy adducts thereof; amine complexes of boron trifluoride; triazine derivatives; and tertiary amines are preferred. Imidazole and its derivatives are more preferred as the curing accelerator. The curing accelerator may be used alone or in combination of two or more types. When it is particularly desired to accelerate curing, the curing accelerator may be used in an amount of preferably 0.01 to 10 parts by mass per 100 parts by mass of the epoxy resin.

The encapsulant composition (d1) may contain a curing agent other than dicyandiamide. Examples of the curing agent other than dicyandiamide include those similar to those described above, but compounds having a phenolic hydroxyl group, acid anhydrides, and compounds having a thiol group are preferred. The amount of the curing agent other than dicyandiamide is preferably 1 to 20 mass % of the total solid content of the composition.

The encapsulant composition (d1) may further contain a thermoplastic resin to facilitate the production of a dry film having a thick resin layer. The thermoplastic resin may be the same as that described above, and may also include a polymer resin having a glass transition point of 20° C. or less and a weight average molecular weight of 10,000 or more. The thermoplastic resin may be used alone or in combination of two or more. The thermoplastic resin is preferably a phenoxy resin. The amount of the thermoplastic resin is preferably 1 to 70% by mass, more preferably 20 to 50% by mass, of the total solid content of the composition. From the viewpoint of reducing haze after curing, the amount is preferably 20% by mass or more, more preferably 40% by mass or more, of the total solid content of the composition.

The encapsulant composition (d1) may contain additives such as acrylic, fluorine, silicone, or other defoamers, leveling agents, and surface conditioners, to the extent that coloring of the cured product can be suppressed. Examples include the BYK series, such as BYK-3550 manufactured by BYK Japan. The amount of these additives is preferably 0.01 to 1.5 mass % of the total solid content of the composition.
The encapsulant composition (d1) may further contain, as necessary, conventionally known additives such as an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a surfactant, a plasticizer, a lubricant, a flow modifier, a thickener, a film-increasing agent, an adhesion imparting agent, a release agent, a polymerization initiator, a sensitizer, an organic filler, an inorganic filler, a rubber-like particle, an ion adsorbent, and a reactive diluent.

In a 50 μm-thick cured film formed from the encapsulant composition (d1), the difference in transmittance at wavelengths of 400, 500, and 600 nm is preferably less than 6%, and more preferably 5% or less. When the difference in transmittance is less than 6%, the color tone is particularly excellent and coloring is suppressed.

The haze of the resin film formed from the encapsulant composition (d1) is preferably 20% or more, more preferably 25% or more.

The haze of the cured film formed from the encapsulant composition (d1) is preferably 10% or less, and more preferably 5% or less.

The encapsulant composition (d1) may be used in the form of a dry film or in liquid form. When used in liquid form, it may be one-component or two-component or more, but from the viewpoint of storage stability, it is preferable to use two-component or more. The dry film may be formed by laminating two or more resin layers of dry films to form a dry film having two or more resin layers. It may also have a resin layer of the encapsulant composition (d1) and a resin layer of another composition. It is difficult to form a uniform thick resin layer by forming a resin layer by coating and drying, but it is possible to easily form a uniform thick resin layer by laminating resin layers to form a thick film. The thick resin layer can be sufficiently encapsulated even if the light-emitting body to be encapsulated has a certain thickness.

((D2) A step of forming an encapsulant having a cured product with a haze of 10% or less on the plurality of light-emitting elements and the light diffusion preventing layer after the step (C))
In step (D2), a light-emitting element is formed using an encapsulant having a haze of 10% or less after curing. The method of formation is not particularly limited, and for example, an encapsulant composition that gives a cured product having a haze of 10% or less may be applied, or the encapsulant composition may be formed into a dry film and laminated.

The encapsulant composition that can produce a cured product with a haze of 10% or less is not particularly limited, but is preferably an encapsulant composition containing an epoxy resin, a thermoplastic resin, an organic solvent, a curing agent, and a colorant, the curing agent being at least one selected from dicyandiamide, a compound having a phenolic hydroxyl group, an acid anhydride, and a compound having a thiol group, and the amount of the colorant blended is 0.01 to 1.2 mass% of the total solid content of the composition. Conventional luminous body encapsulant compositions are transparent, so there is a problem that the luminous body can be seen through when the light is turned off. In addition, if a colorant is blended into the encapsulant composition to hide the luminous body so that the luminous body cannot be seen through when the light is turned off, the luminous body is inhibited from emitting light, so it is not easy to achieve both. According to the encapsulant composition (d2), the luminous body can be concealed when the light is turned off without inhibiting the luminous body's emission, and it is also excellent in the formability of a thick film according to the size of the object to be encapsulated. The encapsulant composition (d2) does not necessarily have the above effect if it is black, but contains the above components and has the characteristic that the haze of the cured product is 10% or less, so that the total light transmittance is within a reasonable range, the light emission of the light-emitting body is not inhibited, and the light-emitting body can be concealed when the light is turned off. Here, the total light transmittance of the cured product is preferably 5% or more and less than 85% at a thickness of 50 μm. The total light transmittance is a value measured using a hazemeter NDH7000II (manufactured by Nippon Denshoku Industries Co., Ltd.), and is not limited to the above device as long as it has a similar measurement principle.

In the encapsulant composition (d2), the epoxy resin may be any of solid epoxy resin, semi-solid epoxy resin, liquid epoxy resin, and crystalline epoxy resin, and among them, it is preferable to contain a liquid epoxy resin from the viewpoint of slit processing of the dry film. Examples of the liquid epoxy resin include the same as those described above. Among the epoxy resins, it is preferable to contain an epoxy resin having an alicyclic skeleton in order to reduce coloring of the cured product so as not to inhibit light emission. The epoxy resin having an alicyclic skeleton is the same as described above. The epoxy resin may be used alone or in combination of two or more types. In the encapsulant composition (d2), the amount of the epoxy resin is preferably 50 to 80 mass% of the total solid content of the composition. In the encapsulant composition (d2), the amount of the epoxy resin having an alicyclic skeleton is preferably 20 to 80 mass% of the total solid content of the composition.

In the encapsulant composition (d2), examples of the thermoplastic resin include those similar to those described above, and the thermoplastic resin may include a polymer resin having a glass transition point of 20°C or less and a weight average molecular weight of 10,000 or more. By including a thermoplastic resin, it becomes easier to produce a dry film having a thick resin layer. The thermoplastic resin may be used alone or in combination of two or more types. The thermoplastic resin is preferably a phenoxy resin. From the viewpoint of reducing the haze of the cured film, the amount of the thermoplastic resin is preferably 20% by mass or more, and more preferably 30 to 50% by mass, based on the total solid content of the composition.

In the encapsulant composition (d2), the organic solvent may be the same as described above. The organic solvent may be used alone or in a mixture of two or more kinds. The amount of the organic solvent in the composition is preferably 30 to 70 mass %.

The curing agent contained in the sealing material composition (d2) may be the same as those described above, such as dicyandiamide, a compound having a phenolic hydroxyl group, an acid anhydride, and a compound having a thiol group. The curing agent may be used alone or in combination of two or more. The amount of the curing agent is preferably 1 to 20 mass % of the total solid content of the composition.

The encapsulant composition (d2) contains a colorant in an amount of 0.01 to 1.2 mass% based on the total solid content of the composition. The colorant is not particularly limited, but must be one that provides a total light transmittance of the cured film within a certain range, does not inhibit the emission of the light emitter, and can conceal the light emitter when the light is turned off. Examples of the colorant include carbon black, titanium black, iron oxide, cobalt oxide, and perylene-based black colorants, and these colorants can be used alone or in combination.
The colorant may be a perylene-based colorant or a combination of a colorant having a complementary color to the perylene-based colorant, as long as it does not inhibit the emission of the light-emitting body and can conceal the light-emitting body.
Perylene colorants include those that exhibit colors such as green, yellow, orange, red, purple, and black, and are assigned the following Color Index (CI; published by The Society of Dyers and Colourists) numbers.
- Green: Solvent Green 5
- Orange: Solvent Orange 55
- Red: Solvent Red 135, 179; Pigment Red 123, 149, 178, 179, 190, 194, 224
- Purple: Pigment Violet 29
- Black: Pigment Black 31, 32
Perylene colorants other than those mentioned above can also be used. For example, although they do not have a color index number, BASF's Lumogen (registered trademark) Black FK4280 and Lumogen Black FK4281, which are known as near-infrared transmitting black organic pigments, and Lumogen F Yellow 083, Lumogen F Orange 240, Lumogen F Red 305, and Lumogen F Green 850, which are known as light-collecting fluorescent dyes, can be suitably used because, like other perylene compounds, they have little absorption in the ultraviolet region and high coloring power.

The complementary colorant used in combination with the perylene-based colorant in the encapsulant composition (d2) will be described below. First, the complementary color relationship in the encapsulant composition (d2) will be described.
Since the colorant may not have a color according to the color index color, the external color tone of the cured film of the encapsulant composition is measured and displayed by the method specified in JIS Z8729, the a* value and the b* value indicating the color in the L*a*b* color system are confirmed on the coordinate axes (see FIG. 4), and a colorant that brings the (a* value, b* value) of the cured film obtained in combination with the perylene-based colorant as close as possible to (0, 0) is selected as a colorant having a complementary color relationship. Here, the thickness of the cured film is not particularly limited, but is, for example, 40 μm.
As for (a* value, b* value) that is infinitesimally close to (0, 0), the a value and the b value are each in the range of −5 to +5, and preferably in the range of −2 to +2. Furthermore, the colorants having a complementary color relationship may be either perylene-based colorants or colorants other than perylene-based colorants.

The colorant that has a complementary color relationship with the perylene-based colorant may be any colorant that, when combined with the perylene-based colorant, brings the color system a* value and the color system b* value of each colorant close to 0, and examples of the colorants include the following colorants:
More preferred combinations of perylene-based colorants and colorants having a complementary color relationship include combinations of Pigment Red 149, 178, and 179 with green anthraquinone-based colorants (Solvent Green 3, Solvent Green 20, Solvent Green 28, etc.), and mixtures (combinations) of perylene-based colorants include combinations of a red perylene-based colorant (Pigment Red 149, 178, and 179) with a black perylene-based colorant (Pigment Black 31 and 32), and combinations of a black perylene-based colorant (Pigment Black 31 and 32) with the same black perylene-based colorant (Lumogen (registered trademark) Black FK4280 and 4281).

The colorants may be any combination selected from the group consisting of a yellow colorant and a purple colorant, a yellow colorant, a blue colorant, and a red colorant, a green colorant and a purple colorant, a green colorant and a red colorant, a yellow colorant, a purple colorant, and a blue colorant, and a green colorant, a red colorant, and a blue colorant. In addition, purple colorants, orange colorants, brown colorants, etc. may be combined.

Blue colorants include phthalocyanine and anthraquinone compounds, which are classified as pigments and solvents. In addition, metal-substituted or unsubstituted phthalocyanine compounds can also be used.
Red colorants include monoazo, diazao, azo lake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridone.
Yellow colorants include monoazo-based, disazo-based, condensed azo-based, benzimidazolone-based, isoindolinone-based, and anthraquinone-based.
Green colorants include phthalocyanine and anthraquinone types, and metal-substituted or unsubstituted phthalocyanine compounds can also be used.

Specific examples of purple, orange and brown colorants include Pigment Violet 19, 23, 29, 32, 36, 38, 42; Solvent Violet 13, 36; C.I. Pigment Orange 1, C.I. Pigment Orange 5, C.I. Pigment Orange 13, C.I. Pigment Orange 14, C.I. Pigment Orange 16, C.I. Pigment Orange 17, C.I. Pigment Orange 24, C.I. Pigment Orange 34, C.I. Pigment Orange 36, C.I. Pigment Orange 38, C.I. Pigment Orange 40, C.I. Pigment Orange 43, C.I. Pigment Orange 46, C.I. Pigment Orange 49, C.I. Pigment Orange 51, C.I. Pigment Orange 61, C.I. Pigment Orange 63, C.I. Pigment Orange 64, C.I. Pigment Orange 71, C.I. Pigment Orange 73; C.I. Pigment Brown 23, C.I. Pigment Brown 25; C.I. Pigment Black 1, C.I. Pigment Black 7, etc.

As the carbon black, one or more of known carbon blacks such as channel black, furnace black, thermal black, and lamp black can be used. Resin-coated carbon black may also be used. When carbon black is blended into the encapsulant composition, carbon black powder or a carbon black dispersion may be added.

The amount of the colorant blended is preferably 0.05 to 1.2 mass% of the total solid content of the composition. When carbon black is blended as the colorant, the amount of carbon black blended is preferably 0.05 to 1.2 mass% of the total solid content of the composition.

The encapsulant composition (d2) may contain a curing accelerator. Specific examples of the curing accelerator include the same as those mentioned above, but are preferably imidazole and its derivatives; guanamines; polyamines; organic acid salts and/or epoxy adducts thereof; amine complexes of boron trifluoride; triazine derivatives; tertiary amines; amines; polyphenols; organic phosphines; phosphonium salts; quaternary ammonium salts; styrene-maleic anhydride resin; equimolar reactants of organic polyisocyanate and dimethylamine; metal catalysts, and the like. Imidazole and its derivatives are more preferable as the curing accelerator. The curing accelerator can be used alone or in combination of two or more kinds. When it is particularly desired to accelerate curing, it can be used in the range of preferably 0.01 to 5 parts by mass per 100 parts by mass of epoxy resin. In the case of a metal catalyst, the amount is preferably 10 to 550 ppm, and more preferably 25 to 200 ppm, in terms of metal, per 100 parts by mass of epoxy resin.

The sealing material composition (d2) may contain an inorganic filler, and one type may be used alone or two or more types may be used in combination. As the inorganic filler, silica having a maximum particle diameter of 150 nm or less is preferable. The silica having a maximum particle diameter of 150 nm or less preferably has a sharp particle size distribution. Here, the maximum particle diameter includes not only the particle diameter of the primary particles but also the particle diameter of the secondary particles (aggregates), and may be measured by a dynamic light scattering method. An example of a measuring device using the dynamic light scattering method is NanotracWaveII UT151 manufactured by Microtrack Bell. The silica having a maximum particle diameter of 150 nm or less may be a commercially available product, such as AEROSIL380 manufactured by Nippon Aerosil Co., Ltd. or MEK-EC-2430Z manufactured by Nissan Chemical Industries, Ltd. The silica having a maximum particle diameter of 150 nm or less may be surface-treated. Here, the surface treatment refers to a treatment for improving compatibility with the resin component. The amount of silica having a maximum particle size of 150 nm or less is preferably 0.1 to 20 mass% of the total solid content of the composition. It is preferable that the sealing material composition (d2) does not contain an inorganic filler having a maximum particle size exceeding 150 nm.

The sealing material composition (d2) may contain additives such as acrylic, fluorine, silicone, or other defoaming agents, leveling agents, and surface conditioners. Examples include the BYK series, such as BYK-3550 manufactured by BYK Japan. The amount of these additives is preferably 0.01 to 1.5 mass % of the total solid content of the composition. In addition, other known and commonly used additives may be contained.

The encapsulant composition (d2) may further contain, as necessary, conventionally known additives such as antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, surfactants, plasticizers, lubricants, flow control agents, thickeners, film-increasing agents, adhesion-imparting agents, release agents, polymerization initiators, sensitizers, organic fillers, rubber particles, ion adsorbents, and reactive diluents.

The encapsulant compositions (d1) and (d2) may be used in the form of a dry film or in liquid form. When used in liquid form, they may be one-component or two-component or more, but from the viewpoint of storage stability, two-component or more is preferable. The dry film may be formed by laminating two or more dry film resin layers to form a dry film having two or more resin layers. The dry film may further have a resin layer of another composition. When forming a resin layer by coating and drying, it is difficult to form a uniform thick resin layer, but by laminating resin layers to form a thick film, it is possible to easily form a uniform thick resin layer. The thick resin layer can adequately seal even if the light-emitting body to be sealed has a certain thickness.

The present invention will be specifically described below with reference to examples and comparative examples, but it goes without saying that the present invention is not limited to the following examples. In the following, "parts" and "%" are all based on mass unless otherwise specified.

<Preparation of Curable Resin Composition>
The solvents described in the Examples and Comparative Examples were placed in a container and stirred while heating to 50°C to prevent the solvent from volatilizing, and then the resins other than carbon black and the coupling agent were added. After confirming that the resins were dissolved, the carbon black described in the Examples was added and thoroughly stirred. Then, the mixture was kneaded with a three-roll mill to prepare a curable resin composition. The values in the tables indicate parts by mass unless otherwise indicated in %, and in Table 1, the values other than the solvent indicate the solid content.

<Dispersibility>
The prepared curable resin composition was subjected to confirmation of the degree of dispersion using a 0-50 μm grind gauge in accordance with the method for degree of dispersion specified in JIS K5600-2-5. The evaluation criteria were as follows.
⊚: The degree of dispersion determined from the five-particle value is less than 25 μm.
◯: The degree of dispersion determined by the five-particle value was 25 μm or more and less than 40 μm.
×: The degree of dispersion judged from the value of five grains is 40 μm or more.
-: Not evaluated as it is made up of resin components only.

<Sedimentation of Composition (Ink)>
The prepared curable resin composition was placed in a transparent glass screw tube and stored in a thermostatic chamber set at 23° C. for 12 hours for aging treatment. The curable resin composition was charged 50 mm from the bottom of the screw tube. After aging, the curable resin composition was taken out and visually observed from the side to confirm the sedimentation state of the curable resin composition. The evaluation criteria were as follows.
◎: No settling is observed.
A: A transparent supernatant liquid less than 1 mm in size was observed from the upper part of the composition.
x: A transparent supernatant liquid of 20 mm or more was observed above the composition.
-: Not evaluated as it is made up of resin components only.

<Preparation of dry film>
The amount of the solvent was adjusted so that the viscosity of the prepared curable resin composition was 0.5 to 20 dPa·s (rotational viscometer 5 rpm, 25°C), and each was applied to a carrier film (PET film; Toyobo TN-200, thickness 38 μm, size 30 cm x 30 cm) using a bar coater so that the thickness of the resin layer after drying was 40 μm. Next, the resin layer was dried for 5 to 10 minutes at 70 to 120 ° C (average 100 ° C) in a hot air circulation drying oven so that the residual solvent in the resin layer was 0.5 to 2.5 mass%, forming a resin layer on the carrier film. Next, OPP (Alphan FG-201, Fish Eyeless, Oji F Tech) was laminated to the surface of the prepared dry film using a roll laminator set to a temperature of 80 ° C to prepare a dry film with a three-layer structure.

<Transmittance>
The protective film of the obtained three-layered dry film was peeled off, and the film was laminated on a slide glass having a thickness of 1 mm using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho). The lamination was performed under conditions of a lamination temperature of 80 to 110°C and a pressure of 0.5 MPa. Next, the carrier film was peeled off, and the resin layer was cured in a hot air circulation drying oven at 100°C for 30 minutes and at 200°C for 60 minutes. The transmittance of the obtained cured product at 400 nm to 800 nm was measured using a UV-Visible Near-Infrared Spectrophotometer V-700 (manufactured by JASCO). The evaluation criteria are as follows.
◎: Transmittance less than 0.1% in the entire wavelength range. ◯: Transmittance 0.1% or more and less than 0.5% in the entire wavelength range. ×: Transmittance 0.5% or more in the entire wavelength range.

<Warping of the board>
A copper-clad laminate substrate (MCL-E-770G, Hitachi Chemical Co., Ltd., size 10 x 10 cm) with a copper thickness of 12 μm and a plate thickness of 0.1 mm was electrolytically copper plated (Atotech, surface roughness after plating 100 nm or less) to a total copper thickness of 20 μm. Then, CZ-8101 (1 μm etching, MEC Co., Ltd.) was used as a pretreatment. Then, the dry film from which the OPP had been peeled off was laminated on one side of the substrate using a two-chamber vacuum laminator CVP-600 (Nichigo Morton Co., Ltd.). The conditions for lamination and pressing were a temperature of 80 to 110 ° C and a pressure of 0.5 MPa, respectively. Next, the carrier film was peeled off, and the resin layer was cured in a hot air circulation drying oven at 100 ° C for 30 minutes and at 200 ° C for 60 minutes.
Next, a reflow treatment was performed five cycles with a peak temperature of 280° C. and an exposure time of 10 seconds or more at 275° C. or higher, and the warpage of the four corners of the substrate (all warpage shapes were smiles) was measured with a caliper. The evaluation criteria were as follows:
◯: No warping △: The largest warping amount of the four corners is 3 mm or more ×: The largest warping amount of the four corners is 30 mm or more

Table 1 shows the composition of each ingredient and the evaluation results.

The notes *1 to *13 in Table 1 are as follows:
* 1: Mitsubishi Chemical jER828, bisphenol A type epoxy resin * 2: Nippon Kayaku NC-3000H, biphenyl novolac type epoxy compound * 3: Lonza Japan Primaset PT-30, novolac type cyanate resin * 4: DIC EPICLON HPC-8000, active ester resin * 5: Meiwa Kasei HF-1M, phenol novolac resin * 6: Shikoku Kasei 2E4MZ, 2-ethyl-4-methylimidazole * 7: Tokyo Kasei Co., Ltd. Co (II) acetylacetonate * 8: Nagase Chemtex Teisan Resin SG-80H MEK cut product, solid content 18% by mass, acrylic acid ester copolymer resin (functional groups: epoxy group, amide group)
*9: Carbon black powder MA77 (average particle size 23 μm) manufactured by Mitsubishi Chemical Corporation
*10: 20% solution of carbon black powder MA77 manufactured by Mitsubishi Chemical Corporation, PMA dispersion (average particle size 23 μm)
*11: 5% carbon nanofiber solution manufactured by Toyo Color Co., Ltd. *12: KBM-403 manufactured by Shin-Etsu Silicone Co., Ltd., epoxy silane coupling agent

From the results shown in Table 1 above, it can be seen that the curable resin compositions of the Examples are excellent in dispersibility, suppression of carbon black sedimentation, suppression of light transmission, and suppression of substrate warpage.
Furthermore, the same results were obtained when a 40 μm-thick cured product was formed on a slide glass using a spin coater, or when a 40 μm-thick cured product was formed on a substrate using screen printing, confirming that the results are not dependent on the method of forming the cured product.

Example 9 (Preparation of a dry film made from the composition of Example 1)
The thermosetting resin composition of Example 1 was applied to a carrier film (PET film; Toyobo TN-200, thickness 38 μm) using a bar coater so that the thickness of the resin layer after drying was 80 μm. Next, it was dried for 5 to 10 minutes at 70 to 120 ° C (average 100 ° C) in a hot air circulation drying oven so that the residual solvent in the resin layer was 0.5 to 2.5 mass %, and a dry film having a resin layer on a carrier film was obtained. Two sheets of this dry film were prepared, and the resin layers were laminated together using a roll laminator set at a temperature of 80 ° C., to produce a dry film with a three-layer structure (carrier film / resin layer / carrier film) with a resin layer of 160 μm.

[Formulation Example 1: Preparation of dry film of encapsulant composition (d1)]
The thermosetting resin composition obtained in Formulation Example 1 shown in Table 2 below was applied to a carrier film (PET film; Toyobo TN-200, thickness 38 μm) using a bar coater so that the thickness of the resin layer after drying would be 50 μm. Next, the resin layer was dried in a hot air circulation drying oven at 70 to 120° C. (average 100° C.) for 5 to 10 minutes so that the residual solvent in the resin layer was 0.5 to 2.5 mass %, to obtain a dry film having a resin layer on a carrier film. Next, a protective film (OPP (Alphan FG-201, Fish Eyeless, Oji F-Tech)) was laminated to the surface of the prepared dry film using a roll laminator set to a temperature of 80° C. to prepare a dry film with a three-layer structure.

<Transmittance>
The protective film of the three-layered dry film obtained in Formulation Example 1 was peeled off, and the film was laminated on a 1 mm-thick glass slide using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho Co., Ltd.). The lamination was performed under conditions of 80 to 110°C lamination temperature and 0.3 MPa pressure. The carrier film was then peeled off, and the resin layer was cured by heating in a hot air circulation drying oven at 100°C for 30 minutes and at 150°C for 60 minutes. The transmittance of the resin layer before curing and the cured product formed on the glass slide was measured at 400 to 800 nm using a UV-Vis-Near-Infrared Spectrophotometer V-700 (manufactured by JASCO Corporation).

The resin film formed with a thickness of 50 μm using the resin composition of Example 1 had a transmittance of 71% before curing and 98% after curing.

[Formulation Example 2: Preparation of dry film of encapsulant composition (d1)]
A three-layer dry film was prepared in the same manner as in the preparation of the dry film of Formulation Example 1, except that the thermosetting resin composition obtained in Formulation Example 1 was changed to the thermosetting resin composition obtained in Formulation Example 2 described in Table 2 below.

<Transmittance>
The transmittance was measured in the same manner as for the three-layered dry film obtained in Formulation Example 1. The resin films having a thickness of 50 μm formed from the resin composition of Formulation Example 2 all had a transmittance of 70% before curing, and a transmittance of 93% after curing.

[Formulation Example 3: Preparation of dry film of encapsulant composition (d2)]
A three-layer dry film was prepared in the same manner as in the preparation of the dry film of Formulation Example 1, except that the thermosetting resin composition obtained in Formulation Example 1 was changed to the thermosetting resin composition obtained in Formulation Example 3 described in Table 2 below.

<Haze measurement>
The protective film of the dry film obtained in Formulation Example 3 was peeled off, and the film was laminated on a 1 mm thick glass slide using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho Co., Ltd.). The lamination was performed under conditions of a lamination temperature of 80 to 110°C and a pressure of 0.3 MPa. Next, the carrier film was peeled off, and the resin layer was cured in a hot air circulation drying oven at 100°C for 30 minutes and at 150°C for 60 minutes. The haze of the cured film formed on the glass slide was measured using a Hazemeter NDH7000II (manufactured by Nippon Denshoku Industries Co., Ltd.). The total light transmittance was also measured using the same device. The total light transmittance was evaluated according to the following criteria.
Evaluation criteria: ◯: Total light transmittance is 5% or more and less than 85%. ×: Total light transmittance is less than 5% or 85% or more.

The haze of the cured product of the resin composition of Example 3 was 2.7%.

[Formulation Example 4: Preparation of dry film of encapsulant composition (d2)]
A three-layer dry film was prepared in the same manner as in the preparation of the dry film of Formulation Example 1, except that the thermosetting resin composition obtained in Formulation Example 1 was changed to the thermosetting resin composition obtained in Formulation Example 4 described in Table 2 below.

<Haze measurement>
The haze was measured in the same manner as for the three-layered dry film obtained in Formulation Example 3.
The haze of the cured product of the resin composition of Formulation Example 4 was 9.8%.

[Example 10]
<Preparation of a Substrate Having a Light-Emitting Element Sealed with a Dry Film>
The carrier film on one side of the 160 μm dry film obtained in Example 9 was peeled off, and the film was laminated on a substrate on which a light-emitting element (height 150 μm, length 200 μm, width 380 μm) was mounted using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho) at a temperature of 80 to 110° C. and a pressure of 0.3 MPa. The resin layer (light diffusion prevention layer) was then cured in a hot air circulation drying oven at 100° C. for 30 minutes and at 200° C. for 60 minutes.
After the resin layer was hardened, the resin layer on the light-emitting element was dry etched using an anisotropic plasma device (TAIKAI manufactured by JCU Corporation) under conditions of a mixed gas of _CF4 (gas supply rate 70 sccm)/ _O2 (gas supply rate 700 sccm)/ ^N2 (gas supply rate 70 sccm), an output of 2700 W, and 360 seconds, thereby thinning the light diffusion prevention layer.
The OPP of the dry film obtained in Formulation Example 1, which had a transmittance of 85% or more after curing, was peeled off, and the substrate was laminated at a temperature of 80 to 110°C and a pressure of 0.3 MPa using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho). The resin layer was then cured in a hot air circulation drying oven at 100°C for 30 minutes and 150°C for 60 minutes. This enabled the production of a substrate having light-emitting elements with no light leakage between the light-emitting elements and high brightness on the light-emitting surface.
[Example 11]
<Preparation of a Substrate Having a Light-Emitting Element Sealed with a Dry Film>
The carrier film on one side of the 160 μm dry film obtained in Example 9 was peeled off, and the film was laminated on a substrate on which a light-emitting element (height 150 μm, length 200 μm, width 380 μm) was mounted using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho) at a temperature of 80 to 110° C. and a pressure of 0.3 MPa. The resin layer (light diffusion prevention layer) was then cured in a hot air circulation drying oven at 100° C. for 30 minutes and at 200° C. for 60 minutes.
After the resin layer was hardened, the resin layer on the light-emitting element was dry etched using an anisotropic plasma device (TAIKAI manufactured by JCU Corporation) under conditions of a mixed gas of _CF4 (gas supply rate 70 sccm)/ _O2 (gas supply rate 700 sccm)/ ^N2 (gas supply rate 70 sccm), an output of 2700 W, and 360 seconds, thereby thinning the light diffusion prevention layer.
The OPP of the dry film obtained in Formulation Example 2, which had a transmittance of 85% or more after curing, was peeled off, and the substrate was laminated at a temperature of 80 to 110°C and a pressure of 0.3 MPa using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho). The resin layer was then cured in a hot air circulation drying oven at 100°C for 30 minutes and 150°C for 60 minutes. This enabled the production of a substrate having light-emitting elements with no light leakage between the light-emitting elements and with a high brightness on the light-emitting surface.

[Example 12]
<Preparation of a Substrate Having a Light-Emitting Element Sealed with a Dry Film>
The carrier film on one side of the 160 μm dry film obtained in Example 9 was peeled off, and the film was laminated on a substrate on which a light-emitting element was mounted using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho) at a temperature of 80 to 110° C. and a pressure of 0.3 MPa. The resin layer (light diffusion prevention layer) was then cured in a hot air circulation drying oven at 100° C. for 30 minutes and at 200° C. for 60 minutes.
After the resin layer was hardened, the resin layer on the light-emitting element was dry etched using an anisotropic plasma device (TAIKAI manufactured by JCU Corporation) under conditions of a mixed gas of _CF4 (gas supply rate 70 sccm)/ _O2 (gas supply rate 700 sccm)/ _N2 (gas supply rate 70 sccm), an output of 2700 W, and 360 seconds, thereby thinning the light diffusion prevention layer.
The OPP of the dry film obtained in Formulation Example 3, in which the haze of the cured product was 10% or less, was peeled off, and the substrate was laminated at a temperature of 80 to 110°C and a pressure of 0.3 MPa using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho). The resin layer was then cured in a hot air circulation drying oven at 100°C for 30 minutes and at 150°C for 60 minutes. This enabled the production of a substrate having light emitting elements with no light leakage between light emitting elements, high brightness on the light emitting surface, and high concealment of the light emitting elements.
[Example 13]
<Preparation of a Substrate Having a Light-Emitting Element Sealed with a Dry Film>
The carrier film on one side of the 160 μm dry film obtained in Example 9 was peeled off, and the film was laminated on a substrate on which a light-emitting element was mounted using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho) at a temperature of 80 to 110° C. and a pressure of 0.3 MPa. The resin layer (light diffusion prevention layer) was then cured in a hot air circulation drying oven at 100° C. for 30 minutes and at 200° C. for 60 minutes.
After the resin layer was hardened, the resin layer on the light-emitting element was dry etched using an anisotropic plasma device (TAIKAI manufactured by JCU Corporation) under conditions of a mixed gas of _CF4 (gas supply rate 70 sccm)/ _O2 (gas supply rate 700 sccm)/ _N2 (gas supply rate 70 sccm), an output of 2700 W, and 360 seconds, thereby thinning the light diffusion prevention layer.
The OPP of the dry film obtained in Formulation Example 4, in which the haze of the cured product was 10% or less, was peeled off, and the substrate was laminated at a temperature of 80 to 110°C and a pressure of 0.3 MPa using a vacuum laminator MVLP-500 (manufactured by Meiki Seisakusho). The resin layer was then cured in a hot air circulation drying oven at 100°C for 30 minutes and at 150°C for 60 minutes. This enabled the production of a substrate having light-emitting elements with no light leakage between light-emitting elements, high brightness on the light-emitting surface, and extremely high concealment of the light-emitting elements.

Notes *1 to *8 in Table 2 are as follows:
*1: Bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Corporation)
*2: Hydrogenated bisphenol A epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd.)
*3: Phenol novolac type epoxy resin (DIC Corporation)
*4: Phenoxy resin (manufactured by Mitsubishi Chemical Corporation) (solid content 30% by mass)
*5: Dicyandiamide (Mitsubishi Chemical Corporation)
*6: Phenol novolac resin (manufactured by Meiwa Kasei Co., Ltd.)
*7: 2-Ethyl-4-methylimidazole (manufactured by Shikoku Chemical Industry Co., Ltd.)
*8: Carbon black (manufactured by Mitsubishi Chemical Corporation)

1 Optical sensor module 2 Light emitting element 3 Detector 4 Partition wall 5 Object 10, 20 Light emitting electronic component having sealing material on light diffusion prevention layer 11 Substrate 12, 13, 14 Light emitting element (LED chip)
15 Light diffusion prevention layer before curing 16 Light diffusion prevention layer 17 Sealing material

Claims (8)

A polymer resin having a glass transition point of 20° C. or lower and a weight average molecular weight of 10,000 or more;
Epoxy resin,
Carbon black,
A curable resin composition comprising the above-mentioned carbon black and containing no inorganic filler other than the above-mentioned carbon black ,
In a cured film obtained by heating at 100° C. for 30 minutes and at 200° C. for 60 minutes, the transmittance at a film thickness of 40 μm at a light wavelength of 400 nm to 800 nm is less than 0.5%,
A curable resin composition for use as a light diffusion prevention layer interposed between a plurality of light emitting elements . The curable resin composition according to claim 1, further comprising at least one of a compound having a phenolic hydroxyl group, a compound having an active ester group, a compound having a cyanate ester group, and a compound having a maleimide group as a curing agent. 3. A dry film comprising a resin layer obtained by applying the curable resin composition according to claim 1 or 2 to a film and drying the applied resin layer. A cured product obtained by curing the curable resin composition according to claim 1 or 2 , or the resin layer of the dry film according to claim 3 . An electronic part comprising the cured product according to claim 4 . A light-emitting electronic component comprising: a substrate having a plurality of light-emitting elements; a light-diffusion prevention layer formed between the plurality of light-emitting elements and comprising the cured product according to claim 4 ; and a sealant formed on the plurality of light-emitting elements and the light-diffusion prevention layer. (A) forming a light diffusion preventing layer on a substrate having a plurality of light emitting elements, the light diffusion preventing layer being made of a resin layer of the curable resin composition according to claim 1 or 2 or the dry film according to claim 3 so as to cover the plurality of light emitting elements;
(B) thermally curing the light diffusion preventing layer;
(C) etching the heat-cured light diffusion prevention layer to remove or thin the light diffusion prevention layer on the light emitting elements;
(D1) A method for producing a light-emitting electronic component, comprising the step of forming an encapsulant having a transmittance (transmittance at a light wavelength of 400 nm to 800 nm through a cured film having a thickness of 50 μm) of 85% or more on the plurality of light-emitting elements and the light diffusion preventing layer after the step (C). (A) forming a light diffusion preventing layer on a substrate having a plurality of light emitting elements, the light diffusion preventing layer being made of a resin layer of the curable resin composition according to claim 1 or 2 or the dry film according to claim 3 so as to cover the plurality of light emitting elements;
(B) thermally curing the light diffusion preventing layer;
(C) etching the heat-cured light diffusion prevention layer to remove or thin the light diffusion prevention layer on the light emitting elements;
(D2) After step (C), a process for forming an encapsulant having a haze of 10% or less after curing on the plurality of light-emitting elements and the light diffusion preventing layer.