Sheet for forming a sealing layer, and a member in which a plurality of light-emitting elements are sealed

Abstract

Provided is a sheet for forming a sealing layer that is excellent not only in embedability but also in water vapor barrier properties, and that makes the presence of boundaries between members difficult to discern, with the object of providing a sealed member that is excellent in migration resistance and boundary invisibility. A sheet for forming a sealing layer for filling the space between light-emitting elements for a display using a plurality of light-emitting elements as light sources and covering the surfaces on the side where the light of the plurality of light-emitting elements is emitted, wherein the sheet for forming a sealing layer has a first film 2, a sealing layer precursor α, and a second film 5 arranged in this order, and the sealing layer precursor α has a water vapor transmission rate of less than 100 [g / (m 2 ·24 h)] and a moisture absorption rate of 1.5 mass% or less, and the sealing layer precursor α has a colorless resin composition layer 3 for embedding with a refractive index of 1.51 ± 0.03 and a water vapor barrier layer 4 with a refractive index of 1.53 ± 0.03.

Description

Technical Field

[0001] The present disclosure relates to a sheet for forming a sealing layer and a member in which a plurality of light-emitting elements are sealed. Specifically, it relates to a sheet for forming a sealing layer that can be suitably used for sealing a plurality of micro-LED elements, and a member in which a plurality of micro-LED elements are sealed.

Background Art

[0002] In recent years, displays have been actively developed using various light-emitting elements for further performance improvement. Specifically, various display specifications such as backlight-type displays using liquid crystals or quantum dots, displays using self-emitting elements such as mini / micro LEDs or organic ELs, plasma displays, and electrophoretic displays have been studied, and their applications range from large display applications such as signage and TVs over 40 inches and 50 inches to small sizes such as tablets, personal computers, smartphones, and wearable devices. In particular, the development of LED-based displays has been progressing day by day, and Patent Documents 1 to 4 describe sealing sheets for sealing a plurality of LED elements.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, with the progress of miniaturization, especially in micro-sized LED elements, when the distance between LED elements becomes narrower, finer and denser circuits are prone to corrosion (hereinafter also referred to as migration) due to water vapor and ion precipitation. In addition, in a display formed by arranging a large number of members in which a plurality of light-emitting elements are sealed, there is a problem that the boundary between the members becomes visible and the display performance as a display deteriorates.

[0005] The present disclosure has been made in view of the above problems, and provides a sheet for forming a sealing layer for sealing a micro-LED element, which is excellent not only in embedding property but also in water vapor barrier property, and makes it difficult to recognize the existence of the boundary between members, and an object is to provide a sealed member excellent in migration resistance and invisibility of the boundary.

Means for Solving the Problems

[0006] As a result of intensive studies by the present inventors, it has been found that a micro-LED member capable of solving the above problems can be manufactured with high quality and efficiency by the following sheet for forming a sealing layer, and the present invention of [1] to [7] below has been completed.

[0007] [1] A sheet for forming a sealing layer for filling the space between light-emitting elements for a display using a plurality of light-emitting elements as light sources and covering the surface on the side where the light of the plurality of light-emitting elements is emitted, The sheet for forming a sealing layer has a first film 2, a sealing layer precursor α, and a second film 5 arranged in this order, The sealing layer precursor α has a water vapor transmission rate of less than 100 [g / (m 2 ·24 hours)] and a moisture absorption rate of 1.5 mass% or less, The sealing layer precursor α has a refractive index of 1.51 ± 0.03 and a water vapor transmission rate of 100 [g / (m 2 ·24 hours)] or more, a colorless resin composition layer 3 for embedding, and a refractive index of 1.53 ± 0.03 and a water vapor transmission rate of 100 [g / (m 2· having a water vapor barrier layer 4 of less than a sheet for forming a sealing layer.

[0008] [2] The sheet for forming a sealing layer according to [1], wherein the water vapor barrier layer 4 is a thermoplastic olefin film.

[0009] [3] The tensile storage modulus E'3 of the colorless resin composition layer 3 for embedding at 100 °C (100) , the tensile storage modulus E'4 of the water vapor barrier layer 4 (100) , and the tensile storage modulus E'5 of the second film 5 (100) satisfy the following relationship, the sheet for forming a sealing layer according to [1] or [2]. E'4 (100) / E'3 (100) is 100 to 1000 and, E'5 (100) / E'4 (100) is 0.5 to 3

[0010] [4] The sheet for forming a sealing layer according to any one of [1] to [3], wherein the total light transmittance of the sealing layer precursor α is 85% or more.

[0011] [5] having a substrate and a plurality of light emitting elements placed thereon at intervals, at least a part of the depth direction of the individual gaps between the light emitting elements has a refractive index of 1.51 ± 0.03 and a water vapor transmission rate of 100 [g / (m 2 ·24 hours)] or more and is filled with a cured product 3' of a colorless resin composition 3 for embedding, the side that emits light from the plurality of light emitting elements is covered in the order of the cured product 3' and a water vapor barrier layer 4 having a refractive index of 1.53 ± 0.03 and less than 100 [g / (m 2 ·24 hours)], a member in which a plurality of light emitting elements are sealed.

[0012] [6] At least a part of the depth direction of the individual gaps between the light-emitting elements and / or at least a part of the bottom surface of the individual gaps are filled with the cured product 9' of the colored resin composition 9 for embedding, and the remaining portions of the individual gaps between the light-emitting elements are filled with the cured product 3' of the colorless resin composition 3 for embedding, a member in which the plurality of light-emitting elements described in [5] are sealed.

[0013] [7] The member in which the plurality of light-emitting elements described in "5" or [6] are sealed, wherein the water vapor barrier layer 4 is a thermoplastic olefin film.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0015] Hereinafter, the present disclosure will be described in detail. Note that the embodiments described below are examples for explaining the present disclosure. The present disclosure is not limited to the following embodiments, and also includes modified examples implemented without changing the gist of the present disclosure. In this specification, the numerical range specified using "~" shall include the numerical values described before and after "~" as the lower limit value and the upper limit value range. (Meth)acrylic acid means acrylic acid and methacrylic acid. In addition, various components appearing in this specification may be each independently used alone or in combination of two or more without particular annotation. When two or more are used in combination, the content rate uses the total value.

[0016] [Sheet for Forming Sealing Layer] The sheet 1 for forming a sealing layer of the present disclosure is a sheet for forming a sealing member used for forming a display. The sealing member is a member in which a light-emitting element (for example, a micro LED element) is sealed on a substrate, and the sheet 1 for forming a sealing layer of the present disclosure is a sheet for sealing a plurality of light-emitting elements on a substrate. As shown in FIG. 1(1), in the sheet 1 for forming a sealing layer, a first film 2, a sealing layer precursor α, and a second film 5 are arranged in this order. The sealing layer precursor α has a colorless resin composition layer 3 for embedding and a water vapor barrier layer 4.

[0017] <Sealing layer precursor α> It is important that the sealing layer precursor α has a water vapor transmission rate of less than 100 [g / (m 2 ·24 h)] and a moisture absorption rate of 1.5 mass% or less. The water vapor transmission rate is preferably 70 [g / (m 2 ·24 h)] or less, more preferably 50 [g / (m 2 ·24 h)] or less, even more preferably 30 [g / (m 2 ·24 h)] or less, and particularly preferably 10 [g / (m 2 ·24 h)] or less. The moisture absorption rate is preferably 1 mass% or less, and more preferably 0.8 mass% or less. The water vapor transmission rate means the moving speed of water vapor, and the moisture absorption rate means the storage property of water vapor. By making the water vapor transmission rate and the moisture absorption rate as small as possible, it becomes difficult for water vapor to pass through and be contained, and the migration resistance of the member after sealing can be improved. By improving the migration resistance, the usability of the display in a higher temperature and higher humidity environment is expanded. The water vapor transmission rate is measured using a water vapor transmission rate measuring device: C390H (conforming to ISO 15106-2, ASTM F1249) manufactured by Labthink, with a transmission area of 5 cm 2 under the measurement conditions of 40 °C × 90% RH for about 24 hours, and refers to the numerical value [g / (m 2 ·24 h)]. Note that although the measured value does not change, the surface that touches water vapor during the measurement shall be the surface of the colorless resin composition layer side. The moisture absorption rate is measured by weighing the mass of a film with an area of 10 cm 2 under the environment of 23 °C and 50% RH, then leaving it to stand in the environment of 40 °C and 90% RH for 24 hours to absorb moisture, then returning it to the environment of 23 °C and 50% RH, and weighing the mass of the sample after standing within 1 hour. The change rate of the mass obtained based on the following formula is defined as the moisture absorption rate. Moisture absorption rate (%) = [(value after moisture absorption ÷ value before moisture absorption) - 1] × 100)

[0018] The thickness of the sealing layer precursor α is preferably 10 to 100 μm, more preferably 12 to 50 μm, and particularly preferably 15 to 30 μm. By being 10 μm or more, the water vapor barrier property can be improved, and by being 100 μm or less, the transparency can be maintained at a high level. By setting it within the particularly preferred range, a display can be obtained that exhibits a high water vapor barrier property at a high level while having high transparency and excellent color development and display performance.

[0019] <Colorless resin composition layer 3 for embedding> The colorless resin composition layer 3 for embedding (hereinafter sometimes abbreviated as the colorless resin composition layer 3, the colorless resin composition layer, or the resin composition layer 3) is for sealing the light-emitting element placed on the substrate, and it is important that the refractive index is 1.51 ± 0.03, and it is preferable that the difference from the refractive index of the substrate on which the light-emitting element is placed is as small as possible. The substrate will be described later. Also, from the viewpoint of the display performance as a display, it is important that the resin composition layer 3 for embedding is colorless, more precisely colorless and transparent. Specifically, from the viewpoint of being colorless, it is important that the b value in the Lab value is 1.5 or less, and preferably 1.0 or less. Also, from the viewpoint of transparency, it is important that the haze is 3.0 or less, and preferably 1.0 or less.

[0020] Note that it is desirable that the colorless resin composition layer 3 also has excellent water vapor barrier property. However, it is difficult to achieve both embeddability and water vapor barrier property, and the water vapor transmittance is 100 [g / (m 2 ·24 hours)] or more in the sense that the water vapor transmittance is larger than that of the water vapor barrier layer 4 described later.

[0021] Also, it is important that the colorless resin composition layer is hydrophobic, and the moisture absorption rate measured in the same manner as the sealing layer precursor α is preferably 1.5% or less, more preferably 1.0% or less. When it exceeds 1.5%, even if the water vapor transmission rate is low and it is difficult for water vapor to pass through, if it is easy to absorb water vapor, the cured product of the colorless resin composition layer after sealing is also easy to absorb water vapor. The cured product of the colorless resin composition layer will be sandwiched between the substrate and the water vapor barrier layer as described later, but it is also important not to absorb water vapor as much as possible until it is sandwiched. Also, after being sandwiched, it is important to suppress and prevent the absorption of water vapor from the end face. The absorbed moisture can easily cause the cured product of the colorless resin composition layer to turn white at the interface with the substrate or the LED element, or cause migration (ion precipitation or circuit corrosion) through water. Even a slight whitening of the cured product significantly impairs the display performance, and is a fatal defect especially for a transparent display. By having the moisture absorption of the colorless resin composition layer at 1.0% or less, the possibility of using the display in a higher temperature and more humid environment is expanded.

[0022] From the perspective of embeddability, the thickness of the colorless resin composition layer is 5 to 50 μm, preferably 10 to 40 μm, and more preferably 15 to 30 μm. By setting the thickness of the colorless resin composition layer within the above range, in order to appropriately disperse and sufficiently homogenize the pressure applied to the resin composition layer 3 in the pressing process, the embeddability is improved. By setting it within the above range, the pressure transmission applied to the colorless resin composition layer in the pressing process described later is controlled, and the colorless resin composition layer flows uniformly, resulting in good embeddability.

[0023] The colorless resin composition layer contains at least resin (A) and polymerization initiator (C). The resin (A) is a substance that has the function of adhering and fixing objects to each other as a binder. The colorless resin composition layer 3 comes into contact with the top surface of the micro-LED element in steps (IV) to (V) of FIG. 3, is embedded along the shape of the object β1 to be sealed, and functions to fix the sealing layer to the object β1 to be sealed by curing the colorless resin composition layer in step (VI) of FIG. 3. The same applies to the cases of FIGS. 4 to 7, and the same applies to the case of FIG. 8 except that there is no step of embedding the colorless resin composition layer along the shape of the object β3 to be sealed.

[0024] The glass transition point of the colorless resin composition layer is the peak top temperature (tanδ peak temperature) of the loss tangent obtained by dynamic viscoelasticity measurement, which is the temperature at which the tanδ curve reaches a maximum. When there are two or more peaks, it indicates the peak temperature on the lowest temperature side. The tanδ peak temperature is preferably 25 to 100 °C, more preferably 40 to 80 °C, and even more preferably 50 to 70 °C. When the tanδ peak temperature is within the above range, in step (IV) of FIG. 3, it does not stick firmly while in contact with the object β1 to be sealed, so it is easy to remove misalignment and entrapped air. Also, the more preferable range is higher than the operating temperature (40 °C) of the LED, so the resin is less likely to deteriorate and less likely to turn yellow. Note that the tanδ peak temperature of the colorless resin composition layer can be adjusted according to the type and composition of the resin (A). When the resin (A) is a (meth)acrylic resin, the tanδ peak temperature can be increased by increasing the content of the acrylic monomer that forms a homopolymer with a high glass transition temperature (Tg). If it is desired to lower the tanδ peak temperature, the opposite adjustment can be made. For the glass transition temperature (Tg) of the homopolymer in the present disclosure, the values described in POLYMER HANDBOOK, 1999, FOURTH EDITION can be used.

[0025] The above-mentioned loss tangent (tanδ) is the ratio of the loss elastic modulus to the storage elastic modulus obtained by dynamic viscoelasticity measurement in the tensile mode at a frequency of 10 Hz and -50 to 150 °C. The dynamic viscoelasticity and loss tangent (tanδ) in the present disclosure are measured by the method described in the examples below. When the resin composition layer 3 contains either a polymerization initiator (C) or a crosslinking agent, the polymerization / crosslinking reaction during measurement is in an incomplete state. Further, it is preferable to measure a sheet having a thickness of 50 μm or more. When measuring a sheet having a thickness less than this, two sets of sealing sheets without the first film are prepared, and the colorless resin composition layers 3 are laminated together with a laminator to produce a laminate of the second film / colorless resin composition layer 3 / second film. Further, the second film on one side of the above laminate is peeled off, and the colorless resin composition layer 3 of the sealing sheet is repeatedly laminated so as to be 50 μm or more, and then the dynamic viscoelasticity may be measured.

[0026] The resin (A) needs to be excellent in embeddability and transparency for sealing, and various resins can be selected. (Meth)acrylic resins, urethane resins such as polyurethane resins and polyurethane-urea resins, epoxy resins, maleic resins, styrene-maleic acid copolymers, polystyrene resins, polybutadiene resins, polyester resins, condensation-type polyester resins, addition-type polyester resins, melamine resins, polycarbonate resins, oxetane resins, phenoxy resins, polyimide resins, polyamide-imide resins, alkyd resins, amino resins, polyamide resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, fluorine resins, butyral resins, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, vinyl-based resins, rubber-based resins, cyclized rubber-based resins, celluloses, polyethylene (HDPE, LDPE), etc. are mentioned. (Meth)acrylic resins, urethane resins, and epoxy resins excellent in embeddability and transparency are preferable, and (meth)acrylic resins that are particularly less likely to yellow due to heat, light, etc. are more preferable. The resin (A) can be used alone or in combination of two or more.

[0027] The weight average molecular weight (Mw) of the resin (A) is preferably from 10,000 to 1,000,000, more preferably from 30,000 to 300,000, and even more preferably from 50,000 to 150,000. By setting the weight average molecular weight (Mw) of the resin (A) to 1,000,000 or less, it is difficult to gel and less likely to impair transparency. By being 10,000 or more, the coating film strength is improved while the embedding property is excellent. By being in a more preferable range, it is difficult to deteriorate and yellow due to heat or light, the moisture absorption rate decreases, and the quality of the completed display is improved. Incidentally, the weight average molecular weight (Mw) is a value in terms of polystyrene measured by gel permeation chromatography (GPC). The weight average molecular weight (Mw) in the present disclosure was measured by the method described in the examples below.

[0028] The resin (A) preferably has at least one radically polymerizable functional group that can be used for polymerization / crosslinking reactions by utilizing ions or radicals generated by heat or light. Examples of the radically polymerizable functional group include (meth)acryloyl group, N-vinyl group, vinyl ether group, allyl group, unsaturated carboxylic acid group, etc. The functional group may be appropriately selected according to the reactivity with the resins (A), the polymerization initiator (C) described later, and the crosslinking agent, and may be a self-crosslinkable functional group.

[0029] [(meth)acrylic resin] (meth)acrylic resin is an acrylic copolymer obtained by copolymerizing (meth)acrylate monomers, and is a polymer having constitutional units based on 2 to 20,000 monomers. Preferable examples of the (meth)acrylate monomer include (meth)acrylate alkyl ester monomers. When introducing a functional group that can be used for polymerization / crosslinking reactions, a (meth)acrylic copolymer obtained by copolymerizing a functional group-containing monomer and a (meth)acrylate monomer is preferable.

[0030] (Meta)acrylic acid alkyl ester monomers are compounds obtained by esterifying (meta)acrylic acid to introduce an alkyl group or a cycloalkyl group. The alkyl group or cycloalkyl group may be any of a linear, branched, or cyclic saturated aliphatic hydrocarbon group, and it is preferable that the linear alkyl group has 4 or more carbon atoms because it is excellent in hydrophobicity. Specific examples include methyl (meta)acrylate, ethyl (meta)acrylate, propyl (meta)acrylate, isopropyl (meta)acrylate, n-butyl (meta)acrylate, isobutyl (meta)acrylate, s-butyl (meta)acrylate, t-butyl (meta)acrylate, pentyl (meta)acrylate, hexyl (meta)acrylate, heptyl (meta)acrylate, octyl (meta)acrylate, 2-ethylhexyl (meta)acrylate, isooctyl (meta)acrylate, nonyl (meta)acrylate, isononyl (meta)acrylate, decyl (meta)acrylate, isodecyl (meta)acrylate, undecyl (meta)acrylate, dodecyl (meta)acrylate, tridecyl (meta)acrylate, tetradecyl (meta)acrylate, pentadecyl (meta)acrylate, hexadecyl (meta)acrylate, heptadecyl (meta)acrylate, octadecyl (meta)acrylate, nonadecyl (meta)acrylate, eicosyl (meta)acrylate, lauryl (meta)acrylate, cyclohexyl (meta)acrylate, 4-n-butylcyclohexyl (meta)acrylate, isobornyl (meta)acrylate, and the like. In particular, it is preferable to use n-butyl (meta)acrylate, which is excellent in hydrophobicity, has a good balance between flexibility and rigidity, and is excellent in embedability and transparency.

[0031] (Meta)acrylic resins preferably contain 1 to 100% by mass, more preferably 20 to 99.5% by mass, and even more preferably 80 to 99% by mass of structural units derived from the above (meta)acrylic acid alkyl ester monomers from the viewpoint of adhesion.

[0032] (Meta)acrylic resins preferably have structural units derived from functional group-containing monomers and / or unsaturated bonds. Examples of the functional group-containing monomers include carboxy group-containing monomers, hydroxy group-containing monomers, epoxy group-containing monomers, and amino group-containing monomers. By containing the functional group-containing monomer, the cohesive force of the resin (A) and the adhesion to the substrate and the circuit are improved. Further, a radically polymerizable unsaturated bond can be introduced by utilizing the functional group of the used functional group-containing monomer. Since the hydroxy group-containing monomer and the amino group-containing monomer have high hydrophilicity, they are likely to impair the hydrophobicity. An epoxy group-containing monomer and a carboxy group-containing monomer, which hardly affect the hydrophobicity of the colorless resin composition layer, are preferable.

[0033] Examples of the carboxy group-containing monomer include, for example, (meth)acrylic acid, β-carboxyethyl (meth)acrylate, p-carboxybenzyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, and isocrotonic acid. Among these, from the viewpoint of adhesion, (meth)acrylic acid is preferable. A radically polymerizable unsaturated bond can also be introduced by reacting glycidyl (meth)acrylate or the like with the carboxy group in the (meth)acrylic copolymer.

[0034] Examples of the hydroxy group-containing monomer include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. Among these, from the viewpoint of adhesion, 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate are more preferable. A radically polymerizable unsaturated bond can also be introduced by reacting a compound having an isocyanate group and a (meth)acryloyl group with the hydroxy group in the (meth)acrylic copolymer.

[0035] Examples of the amino group-containing monomer include (meth)acrylic acid monoalkylamino esters such as monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, and monoethylaminopropyl (meth)acrylate.

[0036] For the purpose of introducing an unsaturated bond into the (meth)acrylic resin, an epoxy group-containing monomer can also be used. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 6-methyl-3,4-epoxycyclohexylmethyl (meth)acrylate. Among these, from the viewpoint of reactivity, it is preferable to use glycidyl (meth)acrylate. After obtaining the (meth)acrylic copolymer, it is preferable to react the epoxy group derived from the epoxy group-containing monomer with the carboxy group of a carboxy group-containing monomer such as (meth)acrylic acid to introduce an unsaturated bond such as a (meth)acryloyl group into the (meth)acrylic resin. At this time, the number of epoxy groups in one molecule is preferably 1 or less, and it is preferable that no epoxy group remains.

[0037] The structural unit of the (meth)acrylic resin is determined by the ratio of the blending amounts of the respective monomers blended during the production of the (meth)acrylic resin. That is, when the total amount of the constituent monomers is 100% by mass, the structural unit derived from the functional group-containing monomer is preferably 0.1 to 20% by mass. By having 0.1% by mass, cohesive force can be exhibited, and by being 20% by mass or less, gelation of the resin can be suppressed.

[0038] The functional group-containing monomers mainly include carboxyl group-containing monomers and hydroxyl group-containing monomers. When the functional group-containing monomer is a carboxyl group-containing monomer, it is preferably 0.1 to 10% by mass. When the functional group-containing monomer is a structural unit derived from a hydroxyl group-containing monomer, it is preferably 0.1 to 20% by mass. Being within the above range can increase the cohesive force while suppressing the gelation of the resin. It is preferable to have both a carboxyl group-containing monomer and a hydroxyl group-containing monomer within the range where the total of the structural units derived from the functional group-containing monomer does not deviate from 0.1 to 20% by mass.

[0039] The (meth)acrylic resin may contain structural units derived from (meth)acrylic acid alkyl esters and other monomers copolymerizable with the functional group-containing monomers. For example, monomers having an alkyleneoxy group and other vinyl monomers can be mentioned. For example, methoxyethyl acrylate, methoxydiethylene glycol acrylate, vinyl acetate, vinyl crotonate, and styrene can be exemplified. The structural units derived from the other monomers are preferably 0.1 to 20% by mass in 100% by mass of the (meth)acrylic copolymer.

[0040] The (meth)acrylic resin is obtained by polymerizing a mixture of acrylic monomers. During polymerization, a polymerization initiator can be used as necessary. The content of the polymerization initiator is, for example, 0.01 to 10% by mass based on 100% by mass of the monomer mixture. The polymerization method is not limited. For example, it can be polymerized by solution polymerization, bulk polymerization, emulsion polymerization, or suspension polymerization, and solution polymerization is most preferred because of the ease of polymerization control. Solvents used in solution polymerization can be exemplified by, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, butyl acetate, toluene, xylene, anisole, cyclohexanone, and isopropyl alcohol. The polymerization temperature can be, for example, 60 to 120°C, and the polymerization time can be about 2 to 12 hours.

[0041] When polymerizing the (meth)acrylic resin, a radical polymerization initiator is preferably used as the polymerization initiator. As the radical polymerization initiator, peroxides and azo compounds are suitable.

[0042] [Polymerization initiator (C)] As the initiator (C), either a thermal polymerization initiator or a photoinitiator can be used, and it is preferable to use a thermal polymerization initiator that is less likely to cause problems due to insufficient irradiation for a substrate having a complex shape. Also, in step (VI) of FIG. 3, etc., by curing while applying pressure and heat, it is possible to minimize warping and lifting due to curing shrinkage. Although the photoinitiator can also be cleaved by heat, it is likely to yellow, so the thermal polymerization initiator is preferable because the cleavage residue is less likely to yellow.

[0043] In the present embodiment, a thermal cationic polymerization initiator or a thermal radical polymerization initiator can be used as the thermal polymerization initiator. A thermal radical polymerization initiator is preferable because of the storage stability of the colorless resin composition layer and the high production rate due to the high curing rate after cleavage. The thermal cationic polymerization initiator has a function of generating ions by heat. Examples of the thermal cationic polymerization initiator include sulfonium cation, quaternary ammonium cation, iodonium cation, etc. as the cation component. Examples of the anion component include antimony hexafluoride anion, phosphorus hexafluoride anion, tetrakis(pentafluorophenyl)borate anion, trifluoromethanesulfonic acid, etc. The thermal radical polymerization initiator has a function of generating radicals by heat. Examples of the thermal radical polymerization initiator include organic peroxide polymerization initiators and azo thermal polymerization initiators, and organic peroxide polymerization initiators are preferable from the viewpoint of yellowing property.

[0044] Examples of the organic peroxide polymerization initiator include dialkyl peroxides such as diacetyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, 1,3-bis(t-butylperoxyisopropyl)hexane, (2-ethylhexanoyl)(t-butyl) peroxide; peroxyesters such as dipropionyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, bis(3,5,5-trimethylhexanoyl) peroxide, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, α-cumyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, di-t-butyl peroxyhexahydroterephthalate, 1,1,3,3-tetramethylbutyl peroxy-3,5,5-trimethylhexanoate, t-amyl peroxy 3,5,5-trimethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, dibutyl peroxytrimethyladipate, 2,5-dimethyl-2,5-di-2-ethylhexanoylperoxyhexane, t-hexyl peroxy-2-ethylhexanoate, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate; Ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, t-butyl benzoate, pivaloyl t-butyl peroxide; Peroxyketals such as 2,2-bis(t-butylperoxy)butane, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane 1,1-bis(t-hexylperoxy)cyclohexane, butyl 4,4-bis(t-butylperoxy)pentanoate; Hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylcyclohexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, p-menthane hydroperoxide; Diacyl peroxides such as dibenzoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, diisobutyryl peroxide, bis-3,5,5-trimethylhexanol peroxide, m-toluoyl benzoyl peroxide, succinic peroxide, 2,4-dichlorobenzoyl peroxide; Examples of the peroxydicarbonates include, but are not limited to, bis(t-butylcyclohexyl) peroxydicarbonate, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, t-butyl peroxyisopropyl carbonate, di-2-ethylhexyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-amyl peroxyisopropyl carbonate, t-butyl peroxy-2-ethylhexyl carbonate, 6-bis(t-butylperoxycarbonyloxy)hexane, and the like. From the viewpoint of storage stability, dialkyl peroxides are preferred, and di-t-butyl peroxide is more preferred.

[0045] As the azo thermal polymerization initiator, 2,2'-azobispropionamides are preferred from the viewpoint of storage stability, and 2,2'-azobis(N-butyl-2-methylpropionamide) is more preferred.

[0046] The 10-hour half-life temperature of the thermal radical polymerization initiator is preferably 60 to 180°C, more preferably 70 to 140°C, and even more preferably 80 to 120°C. By setting it at 60°C or higher, the storage stability of the colorless resin composition layer can be improved, and by setting it at 180°C or lower, warpage due to differences in the shrinkage rates of the substrate and the encapsulation layer precursor in step (IV) of Figure 3 and the like can be reduced.

[0047] The 10-hour half-life temperature is the temperature at which the thermal polymerization initiator decreases to half of its initial value after 10 hours due to thermal decomposition. Specifically, a thermal polymerization initiator solution is prepared using an inert solvent with respect to the radicals of the thermal polymerization initiator, and it is sealed in a glass tube that has been purged with nitrogen. This is immersed in a constant temperature bath set at a predetermined temperature for 10 hours for thermal decomposition, and the amount of the remaining thermal polymerization initiator is measured. By performing this series of operations at several temperatures and plotting the results, the half-life can be determined from the obtained straight line.

[0048] The content of the thermal radical polymerization initiator is preferably 0.01 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the resin (A). By setting the content as described above, the adhesion can be suitably adjusted.

[0049] Examples of the photopolymerization initiator include triazine-based photopolymerization initiators, borate-based photopolymerization initiators, carbazole-based photopolymerization initiators, acetophenone-based photopolymerization initiators, and oxime ester-based photopolymerization initiators. Acetophenone-based photopolymerization initiators and oxime ester-based photopolymerization initiators are preferable because they have less yellowing during the heat aging process. From the viewpoint of yellowing, the content of the photopolymerization initiator is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the resin (A).

[0050] [Other Components] The colorless resin composition layer may contain other components as long as the object of the present disclosure is not impaired. For example, a refractive index adjuster, a crosslinking agent, a monomer, a surface adjustment additive, a curing accelerator, a curing retarder, a softening agent, an antistatic agent, a lubricant, an antiblocking agent, an adhesion improver, etc. can be added. Examples of the refractive index adjuster include urethane (meth)acrylate and inorganic fillers.

[0051] Urethane (meth)acrylate has a higher refractive index and is easier to be compatible compared with (meth)acrylic resins. Therefore, it is easy to adjust the refractive index of the colorless resin composition layer for embedding while maintaining transparency.

[0052] Urethane (meth)acrylate is a reaction product of a compound having an isocyanate group and a (meth)acrylate having a hydroxyl group, and has a (meth)acryloyl group at the end of the molecule. As the compound having an isocyanate group, a polyfunctional one is used, and a (meth)acrylate having one hydroxyl group is reacted, or a compound having a monofunctional isocyanate group is used, and a (meth)acrylate having a plurality of hydroxyl groups is reacted, and it is preferable to use a urethane (meth)acrylate having a plurality of (meth)acryloyl groups. A urethane (meth)acrylate having a large Mw can be obtained by reacting a prepolymer having an isocyanate group, which is obtained by reacting various diols and diamines with a relatively low molecular weight compound having an isocyanate group, with a (meth)acrylate having a hydroxyl group.

[0053] Examples of the diols include diols having a linear aliphatic structure and diols having a branched aliphatic structure. Examples of the diamines include diamines having a linear aliphatic structure and diamines having a branched aliphatic structure, as well as diamines having an alicyclic structure.

[0054] The urethane (meth)acrylate having a plurality of (meth)acryloyl groups is rapidly cured by a peroxide or ultraviolet rays due to the unsaturated carbon bond derived from the (meth)acrylate. The obtained cured product has a high crosslink density and is excellent in chemical resistance and transparency. The urethane (meth)acrylate preferably has three or more double-bonded functional groups in one molecule.

[0055] The weight average molecular weight (Mw) of the urethane (meth)acrylate is preferably 300 to 4000. When Mw is 4000 or less, it becomes easy to be compatible with the (meth)acrylate resin, and a colorless resin composition layer excellent in transparency can be obtained. By Mw being 300 or more, bleeding out from the colorless resin composition layer is prevented.

[0056] When the total addition amount of urethane (meth)acrylate to the (meth)acrylic resin is 100% by mass, the ratio of (meth)acrylic resin / urethane (meth)acrylate = 95% / 5% to 60% / 40% is preferable, and 90% / 10% to 80% / 20% is more preferable. Occupying 5% by mass or more of urethane (meth)acrylate makes it easier to increase, and being 40% by mass or less suppresses the bleed-out of urethane (meth)acrylate.

[0057] Examples of the inorganic filler with a refractive index of 1.55 or more among the inorganic fillers include inorganic compounds such as borosilicate glass, alumina, magnesium hydroxide, barium sulfate, calcium carbonate, titanium oxide, zinc oxide, antimony trioxide, magnesium oxide, zirconium oxide, talc, kaolinite, mica, basic magnesium carbonate, sericite, montmorillonite, kaolinite, bentonite, boron nitride, aluminum nitride, titanium nitride, etc. Among these, titanium oxide, aluminum oxide, and zirconium oxide are preferable from the viewpoint of easy adjustment of the refractive index while maintaining transparency. When the refractive index of resin (A) is high, the refractive index of the colorless resin composition layer for embedding can also be adjusted by blending components with a low refractive index.

[0058] The crosslinking agent enhances the cohesive force of the resin composition layer and improves the adhesion by undergoing a crosslinking reaction with the reactive functional groups of resin (A) during hot pressing or heat aging in the pressing process. The crosslinking agent has a plurality of functional groups capable of reacting with the functional groups of resin (A). Examples of the crosslinking agent include known compounds such as silane coupling agents, acid anhydride group-containing compounds, imidazole compounds, isocyanate compounds, aziridine compounds, and amine compounds. Isocyanate compounds, aziridine compounds, and imidazole compounds are preferable for improving the adhesion to circuits and substrates. In particular, silane coupling agents for improving the adhesion to glass, such as glass substrates, are particularly preferable.

[0059] Examples of the aziridine compound include trimethylolpropane tris[3-(aziridin-1-yl)propionate], tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane, and the like.

[0060] The isocyanate compound is an isocyanate having two or more isocyanate groups. Preferred isocyanate compounds include isocyanate monomers such as aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates, as well as their biuret compounds, allophanate compounds, and adduct compounds. From the viewpoint of forming a sufficient crosslinked structure, a trifunctional isocyanate compound is preferred as the isocyanate compound.

[0061] The silane coupling agent is a compound in which a hydrolyzable group such as a methoxy group or an ethoxy group and a functional group such as an epoxy group are bonded to an Si atom via an alkylene group. Examples of the silane coupling agent include alkoxysilane compounds having a (meth)acryloxy group such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyltripropoxysilane, 3-(meth)acryloxypropyltributoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, and 3-(meth)acryloxypropylmethyldiethoxysilane; alkoxysilane compounds having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane, and vinylmethyldiethoxysilane; Alkoxysilane compounds having an amino group such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltripropoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane; Alkoxysilane compounds having a mercapto group such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane; Alkoxysilane compounds having one epoxy group such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltributoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; Tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane; 3-Chloropropyltrimethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, styryltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, hexamethyldisilazane, silicone resins having an alkoxysilyl group in the molecule, and the like can be mentioned. In the case of the same functional group as the resin (A), since the cohesive force is improved and the adhesion is improved by forming a crosslinked structure, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane are preferable.

[0062] The content of the crosslinking agent is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the resin (A). By setting the content as described above, the cohesive force is increased and the adhesion to various objects to be sealed is improved.

[0063] <Water vapor barrier layer 4> Next, the water vapor barrier layer 4 that constitutes the sealing layer precursor α together with the colorless resin composition layer 3 for embedding will be described. The water vapor barrier layer is arranged to suppress the precipitation of ions and the corrosion of the circuit by water vapor, and it is important that the water vapor permeability is low and the moisture absorption rate is low. That is, it is important that the water vapor permeability is less than 100 [g / (m 2 ·24 hours)], preferably 70 [g / (m 2 ·24 hours) or less, more preferably 50 [g / (m 2 ·24 hours) or less, still more preferably 30 [g / (m 2 ·24 hours) or less, and particularly 10 [g / (m 2· It is preferably 24 hours or less. Further, the moisture absorption rate is importantly 1.5 mass% or less, preferably 1 mass% or less, and more preferably 0.8 mass% or less.

[0064] It is important that the refractive index of the water vapor barrier layer 4 is 1.53 ± 0.03, and it is preferable that the difference from the refractive index of the substrate on which the light-emitting element is mounted is as small as possible. The substrate will be described later. Also, from the viewpoint of display performance as a display, it is important that the water vapor barrier layer is colorless, more precisely colorless and transparent, like the colorless resin composition layer 3. Specifically, from the viewpoint of being colorless, it is important that the b value in the Lab value is 1.5 or less, and preferably 1.0 or less. Also, from the viewpoint of transparency, it is important that the haze is 3.0 or less, and preferably 1.0 or less.

[0065] By the way, when manufacturing a sealing member by sealing a light-emitting element mounted on a substrate as shown in FIGS. 4 to 9, a process called molding is involved. Therefore, the water vapor barrier layer is also required to suppress the uneven distribution of pressure during embedding and to suppress the colorless resin composition layer from protruding outside the target location during embedding. Also, in the manufacturing process of the sealing member, a cleaning process with an organic solvent or the like may be involved. Therefore, from the viewpoint of protecting the colorless resin composition layer for embedding and its cured product from being damaged in these processes, low shrinkage and chemical resistance are also required for the water vapor barrier layer. In order to satisfy a certain degree of rigidity, flexibility, and chemical resistance, it is preferably a film of a thermoplastic resin. Examples of the film of a thermoplastic resin include a polyester film, a polyolefin film, a polyvinyl chloride film, a polyurethane film, a nylon film, an acrylic film, a triacetyl cellulose film, etc., and further, those having a metal oxide film such as aluminum oxide on the plastic film are also included. Examples of the polyester film include polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, etc. Examples of the polyolefin film include polypropylene film, polyethylene film, and cycloolefin-based film. Examples of the cycloolefin-based film include cycloolefin (COP) film, and also those obtained by forming a film from cycloolefin copolymer (COC) or cycloolefin block copolymer (CBC). From the viewpoints of high transparency and low heat shrinkage rate, transparent polyimide, polyethylene terephthalate, and polyethylene naphthalate are preferable. From the viewpoint of water vapor barrier property, a polyethylene terephthalate film with a metal oxide film is preferable. However, a cycloolefin-based film with a small refractive index difference from the alkali-free glass, which is important as the substrate on which the light-emitting element is mounted, is particularly preferable.

[0066] The thickness of the water vapor barrier layer is preferably 5 to 50 μm, more preferably 8 to 40 μm, and still more preferably 10 to 20 μm. By being 5 μm or more, the water vapor barrier property can be improved and the embedding property becomes stable. By being 50 μm or less, the transparency can be improved. Since the display is preferably thinner, when the thickness of the water vapor barrier layer is in a more preferable range, the above object can be satisfied at a high level. When in an even more preferable range, when the colorless resin composition layer is embedded in the gap of the light-emitting element, unevenness is less likely to occur on the surface of the water vapor barrier layer, and the water vapor barrier property after sealing is further improved.

[0067] <First film 2>, <Second film 5> As shown in FIG. 1, the sealing layer precursor α is sandwiched between the first film 2 and the second film 5. The first film 2 and the second film 5 are peeled off in the process of sealing a plurality of light-emitting elements 7 placed on the substrate as shown in FIGS. 3 to 7 using a sealing layer forming sheet.

[0068] <First film 2> The first film 2 is not particularly limited, and examples thereof include a polyester film, a polyolefin film, a polyvinyl chloride film, a polyurethane film, a nylon film, an acrylic film, a triacetyl cellulose film, and the like. Examples of the polyester film include a polyethylene terephthalate film, a polybutylene terephthalate film, and a polyethylene naphthalate film. Examples of the polyolefin film include a polypropylene film, a polyethylene film, and a cycloolefin film. From the viewpoint of handling, a polyester film or a polyolefin film is preferable.

[0069] The first film 2 has a release layer on the surface facing the resin composition layer 3. The release layer is preferably formed by applying a release agent such as a silicone resin, an alkyd resin, a fluororesin, or a melamine resin to the film. From the viewpoint of handling (preventing separation during peeling), a release layer using a silicone resin is more preferable. The peeling force of the first film 2 is preferably 0.1 to 3 gf / 20 mm, more preferably 0.3 to 2 gf / 20 mm, and even more preferably 0.5 to 1 gf / 20 mm. The peeling force of the first film 2 can be adjusted by the release treatment of the release layer. For example, it can be adjusted by the type of the release agent, the coating amount of the release agent, and the surface roughness of the release layer. When it is desired to decrease the value of the peeling force, treatments such as increasing the surface roughness and increasing the coating amount of the release agent are effective. When it is desired to increase the value of the peeling force, the opposite adjustment can be made. The peeling force of the first film 2 can be measured, for example, by attaching the second film 5 in the sheet for forming the sealing layer to a SUS plate and peeling the first film 2 from the resin composition layer 3 at a peeling angle of 180° and a peeling speed of 300 mm / min in an environment of 23°C and a relative humidity of 50%. The first film 2 may have a functional layer in addition to the release layer. Specific examples of the functional layer include an antistatic layer and an antiblocking layer.

[0070] The thickness of the first film 2 is preferably 2 to 250 μm, more preferably 10 to 100 μm, and even more preferably 20 to 60 μm. When a release layer or a functional layer is provided on the first film 2, the thickness is a value including the release layer and the release layer. By setting the thickness within the above range, it is possible to control the transfer of the undulation of the first film 2 to the colorless resin composition layer and form a uniform colorless resin composition layer. The first film 2 is preferably directly laminated with the colorless resin composition layer as shown in Fig. 1(1). When the first film 2 is directly laminated with the colorless resin composition layer, the surface roughness Ra on the surface of the first film 2 in contact with the colorless resin composition layer is preferably 0.02 μm or more. The surface roughness of the surface of the first film 2 in contact with the colorless resin composition layer will be reversely transferred to the surface of the colorless resin composition layer. Therefore, by using the first film 2 with the surface roughness as described above, during the process shown in Fig. 3(IV) etc., it becomes difficult for the colorless resin composition layer to excessively adhere to the surface of the light-emitting element, and it is easy to correct the placement position of the sheet for forming the sealing layer. Also, by using a colorless resin composition layer with a surface roughness Ra of 0.02 μm or more, during the processes shown in Fig. 3(V), Fig. 4(V-2) etc., it becomes difficult for air to remain at the interface between the substrate, the light-emitting element, and the colored resin composition layer and the colorless resin composition layer, and the appearance becomes good. That is, from the viewpoints of blocking suppression / prevention and air bite suppression / prevention, the surface roughness Ra of the first film 2 and the surface of the colorless resin composition layer in contact with the first film 2 is preferably 0.02 μm or more, more preferably 0.1 μm or more, and even more preferably 0.5 μm or more. From the point that the size of the unevenness hardly affects the water vapor barrier layer, the upper limit of the surface roughness is preferably 20% or less of the thickness of the colorless resin composition layer.

[0071] Also, the cutting level difference Rδc of the contour curve on the surface in contact with the colorless resin composition layer of the first film 2 is preferably 0.05 μm or more, more preferably 0.1 μm or more, and even more preferably 0.5 μm or more. Also, the cutting level difference Rδc of the contour curve is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 6 μm or less. By transferring the unevenness of the first film 2 to the colorless resin composition layer, when the colorless resin composition layer comes into contact with the LED element or the substrate, it does not adhere immediately, and correction for positional deviation is provided. Furthermore, when embedding in a vacuum environment, it becomes easier to remove voids. By being within a preferable range, it is excellent in correcting positional deviation while sliding on the surface of the object to be sealed, and excellent in removing voids.

[0072] <Second film 5> The second film 5 supports the water vapor barrier layer during pressing and curing (heating or UV irradiation) in the processes shown in FIGS. 3(V) to (VI), FIGS. 4(V-2) to (VI), etc., and functions as a cushion for suppressing pressure unevenness and mold marks. In order to more reliably support the water vapor barrier layer, it is preferable to have a micro-adhesive layer on the surface in contact with the water vapor barrier layer.

[0073] The base material of the second film 5 is not particularly limited. For example, Although not particularly limited, for example, polyester film, polyolefin film, polyvinyl chloride film, polyurethane film, nylon film, acrylic film, triacetyl cellulose film, etc. can be mentioned. Examples of the polyester film include polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, etc. Examples of the polyolefin film include polypropylene film, polyethylene film, cycloolefin film. From the viewpoint of handling, polyimide film, polyester film, or polyolefin film is preferable, and considering heat resistance as well, polyimide film, polyethylene naphthalate film, and polyethylene terephthalate film are more preferable.

[0074] The adhesive layer provided on the surface of the second film 5 can be formed using various adhesives. Examples of the adhesive include acrylic, urethane, silicone, elastomer, and ester types. From the perspective of heat resistance, acrylic, urethane, and silicone types are preferred. Further, from the aspect of having fewer impurities, acrylic or urethane adhesion is preferable. The thickness of the adhesive layer of the second film 5 is preferably 1 to 50 μm, more preferably 2 to 20 μm, and particularly preferably 3 to 10 μm. When it is 1 μm or more, adhesion is exhibited, and when it is 50 μm or less, the adhesive layer does not protrude from the end of the second film 5 during embedding. The adhesive force to the water vapor barrier layer is preferably 1 to 300 gf / 25 mm, more preferably 2 to 200 gf / 25 mm, and even more preferably 3 to 100 gf / 25 mm with respect to the water vapor barrier layer. The adhesive force of the second film 5 to the water vapor barrier layer 4 can be adjusted according to the type of adhesive, coating amount, and surface roughness. When it is desired to reduce the adhesive force, treatments such as roughening the surface roughness are effective, and when it is desired to increase the adhesive force, increasing the coating amount is effective. The adhesive force to the water vapor barrier layer 4 can be measured, for example, by fixing the surface of the colorless resin composition layer 3 of the sealing sheet to a SUS plate and peeling the second film 5 at a peeling angle of 180° and a peeling speed of 300 mm / min in an environment of 23°C and a relative humidity of 50%.

[0075] The thickness of the second film 5 is preferably 12 to 188 μm, more preferably 12 to 100 μm, and even more preferably 20 to 60 μm. By setting it within the above range, the pressure transmission applied to the colorless resin composition layer in the pressing process is controlled, and the colorless resin composition layer flows uniformly, resulting in good embeddability.

[0076] The tensile storage modulus E' at 100°C of each of the aforementioned colorless resin composition layer 3 for embedding, water vapor barrier layer 4, and second film 5 (100) preferably satisfies the following relationship. E’4 (100) / E’3 (100) is 100 to 1000 and, E’5(100) / E’4 (100) is 0.5 to 3 E’3 (100) represents the tensile storage modulus at 100°C of the colorless resin composition layer 3 for embedding E’4 (100) represents the tensile storage modulus at 100°C of the water vapor barrier layer 4 E’5 (100) represents the tensile storage modulus at 100°C of the second film 5, respectively

[0077] E’4 (100) / E’3 (100) is preferably from 100 to 1000, more preferably from 200 to 800, and even more preferably from 400 to 700. E’4 (100) and E’3 (100) being in such a relationship enables excellent embedability into the object to be sealed, while the unevenness derived from the light-emitting element in the object to be sealed does not affect the surface of the water vapor barrier layer. By being 100 or more, the water vapor barrier layer 4, which is sufficiently harder than the colorless resin composition layer 3, can uniformly and sufficiently push the colorless resin composition layer 3 into the concave portion of the object to be sealed. By being 1000 or less, the water vapor barrier layer 4 is not too hard, and the pressure bias due to the unevenness of the object to be sealed does not affect the water vapor barrier layer 4, preventing the formation of an uneven pattern on the surface of the water vapor barrier layer 4 Also, E’5 (100) / E’4 (100) is preferably 0.5 to 3, and more preferably 1.1 to 2.0. E’5 (100) and E’4 (100) being in such a relationship can prevent the formation of an uneven pattern corresponding to the unevenness of the object to be sealed on the surface of the water vapor barrier layer 4. In a more preferable range, since the second film 5 is equivalent to or slightly harder than the water vapor barrier layer 4, the second film 5 can further assist in embedding the resin composition 3 Each tensile storage modulus is a value obtained by measuring the dynamic viscoelasticity using a dynamic viscoelasticity measuring device DVA-200 / L2 (manufactured by IT Measurement & Control Co., Ltd.) at a frequency of 10 Hz, a measurement temperature range of -50 to 150 °C, a heating rate of 5 °C / min, and in a tensile mode, and reading the storage modulus at 100 °C.

[0078] The sheet 1 for forming the sealing layer can be obtained, for example, as follows. A coating liquid for forming a colorless resin composition layer for embedding is applied and dried on one surface of the first film 2 to form a colorless resin composition layer 3 for embedding. Separately, a water vapor barrier layer 4 is laminated on one surface of the second film 5. Then, the colorless resin composition layer 3 for embedding and the water vapor barrier layer 4 are laminated. Alternatively, a coating liquid for forming a colorless resin composition layer for embedding is applied and dried on one surface of the first film 2 to form a colorless resin composition layer 3 for embedding. Next, the water vapor barrier layer 4 is laminated on the colorless resin composition layer 3 for embedding. Next, the second film 5 is laminated on the water vapor barrier layer 4. Or, a water vapor barrier layer 4 is laminated on one surface of the second film 5. Next, a coating liquid for forming a colorless resin composition layer for embedding is applied and dried on the water vapor barrier layer 4 to form a colorless resin composition layer 3 for embedding. Then, the first film 2 is laminated on the colorless resin composition layer 3 for embedding. As the coating method of the coating liquid for forming the colorless resin composition layer for embedding, known methods such as a roll coater method, a comma coater method, a lip coater method, a die coater method, a reverse coater method, a silk screen method, and a gravure coater method can be used. After coating, it can be dried with a hot air oven, an infrared heater, or the like.

[0079] After manufacturing the sealing layer forming sheet 1 or while manufacturing the sealing layer forming sheet, a roll-shaped sealing layer forming sheet can be obtained by winding it around a core in a roll shape. The winding length can be designed according to the application. From the viewpoint of improving productivity, it is preferably 30 m or more, and more preferably 100 m or more. From the viewpoint of manufacturing yield, the winding length is preferably 10,000 m or less. The thickness of the sealing layer forming sheet is preferably 60 to 200 μm from the viewpoint of ease of winding when winding in a roll shape.

[0080] As a method of winding the roll-shaped sealing layer forming sheet 1, the sheet shown in Fig. 1(1) can be wound with the first film 2 on the core side, or as shown in Fig. 1(2), the first film 2 can be wound with the colorless resin composition layer 3 for embedding on the core side in a state where the first film 2 is overlapped on the surface not in contact with the water vapor barrier layer 4 of the second film 5. In the latter case, from the second round onwards, the first film 2 will be in contact with the colorless resin composition layer 3 for embedding. When using the roll-shaped sealing layer forming sheet 1, when the roll is unwound, the first film can be peeled off immediately, and the colorless resin composition layer 3 for embedding can be exposed. Therefore, it is preferable in terms of improving the productivity of the member 8 in which the light-emitting element 7 is sealed. In addition, the latter roll-shaped sealing layer forming sheet 1 can also be obtained by laminating the first film 2 and the second film 5, then laminating the water vapor barrier layer 4 on the other surface of the second film 5, coating and drying a coating liquid for forming a colorless resin composition layer for embedding on the other surface of the water vapor barrier layer 4 to form a colorless resin composition layer for embedding, and winding with the colorless resin composition layer 3 for embedding on the inside.

[0081] [Member 8 in which a plurality of light-emitting elements are sealed] Next, the member 8 in which a plurality of light-emitting elements are sealed (hereinafter also referred to as the sealed member) will be described. As described above, the encapsulated member 8 of the present invention has a substrate 6 and a plurality of light-emitting elements 7 placed thereon at intervals. At least a part of the depth direction of the individual gaps between the light-emitting elements 7 has a refractive index of 1.51 ± 0.03 and a water vapor transmission rate of 100 [g / (m 2 ·24 h)] or more and is filled with a cured product 3' of a colorless resin composition 3 for embedding. The side that emits light from the plurality of light-emitting elements is covered in the order of the cured product 3' and a water vapor barrier layer 4 having a refractive index of 1.53 ± 0.03 and a water vapor transmission rate of less than 100 [g / (m 2 ·24 h). Further, in the encapsulated member 8, at least a part of the depth direction of the individual gaps between the light-emitting elements 7 and / or at least a part of the bottom surface of the individual gaps may be filled with a cured product 9' of a colored resin composition for embedding, and the remaining portions of the individual gaps between the light-emitting elements 7 may be filled with a cured product 9' of a colorless resin composition for embedding.

[0082] FIG. 2 shows various forms of the gaps between the light-emitting elements 7 in the encapsulated member 8. FIG. 2(1) shows a member having no cured product 9' of a colored resin composition in the gap between the light-emitting elements 7, where the gap is filled with a cured product 3' of a colorless resin composition layer, and the cured product 3' is further covered with a water vapor barrier layer 4. Figures 2(2) to (5) show a form in which a cured product 9' of a colored resin composition, that is, a brilliance improvement layer such as a reflective layer or a color mixing prevention layer, is provided in at least a part of the gap of the light emitting element 7. The brilliance improvement layer is disposed on the side surfaces other than the display side (the light emitting surface, the upper surface side in the figure) of the light emitting element 7 and the bottom surface of the gap, and there is no limitation on the arrangement method. As shown in Fig. 2(2), the cured product 9' of the colored resin composition does not completely cover the side surface of the light emitting element 7, or as shown in Fig. 2(3), the cured product 9' of the colored resin composition filling the gap of the light emitting element covers the side surface of the light emitting element 7, and there are irregularities formed by an etching process or the like on the surface of the cured product 9' in the gap. Or, as shown in Fig. 2(4), the cured product 9' of the colored resin composition thinly covers the substrate on the side surface of the light emitting element 7 and the bottom surface of the gap, and has a deep space in the middle depth direction of the gap. Or, as shown in Fig. 2(5), the cured product 9' of the colored resin composition can be disposed in the gap without contacting the light emitting element 7. Depending on the presence or absence of the cured product 9' of the colored resin composition and the shape of the cured product 9' of the colored resin composition, the shape of the object to be embedded by the colorless resin composition layer 3 can vary. However, the interface between the cured product 3' of the colorless resin composition layer and the water vapor barrier layer 4 laminated on the cured product 3' of the colorless resin composition layer, and the surface of the water vapor barrier layer 4 are preferably as parallel as possible to the surface of the substrate 6 on which the light emitting element 7 is placed, regardless of the shape of the gap to be sealed, and the surface of the water vapor barrier layer 4 is preferably as smooth as possible.

[0083] <Substrate 6> The material of the substrate 6 on which the light emitting element 7 is placed is not particularly limited, and examples thereof include acrylic, urethane, polycarbonate, epoxy, polyimide, glass, glass epoxy, paper, cloth, aluminum, ceramic, or polyethylene terephthalate. It can also be developed for transparent display applications, and glass is preferable from the viewpoints of cost, durability, and transparency, and it is preferable to have an electrode portion. In the sense of preventing corrosion of the light emitting element by ionic components, as the glass, non-alkali glass is preferable. Further, the refractive index of the glass substrate is preferably 1.49 to 1.59, more preferably 1.50 to 1.55. The refractive index can be adjusted, for example, by adjusting the ratio of silicon oxide, aluminum oxide, and boron oxide. Generally, the refractive index can be increased by increasing the ratio of boron oxide. In addition to boron oxide, the refractive index can also be increased by adding alkaline earth oxides.

[0084] <Light-emitting element 7> Examples of the light-emitting element 7 placed on the substrate 6 include LED elements, and micro-LED elements are preferred. The size of the micro-LED element is preferably such that the thickness is 100 μm or less and the area in plan view is 40,000 μm 2 The following are more preferred, with a thickness of 50 μm or less and an area in plan view of 10,000 μm 2 The following are even more preferred, with a thickness of 20 μm or less and an area in plan view of 2,500 μm 2 The following are even more preferred. By mounting a plurality of such LED elements on a substrate on which wirings and circuits are formed, a display using a plurality of optical semiconductor elements as light sources is formed. The distance between adjacent micro-LED elements placed on the substrate is, for example, 10 to 5,000 μm. When red, green, and blue micro-LED elements are set as one pixel and placed on the substrate, the distance between adjacent pixels is, for example, 10 to 2,000 μm, preferably 20 to 1,800 μm, and more preferably 500 to 1,500 μm. The distance between adjacent micro-LED elements within one pixel is, for example, 10 to 200 μm, preferably 10 to 100 μm, and more preferably 20 to 60 μm. The number of micro-LED elements is not particularly limited. In display applications, the number of micro-LED elements used is determined by the display size and the number of pixels. Also, the emission color of the micro-LED elements is not particularly limited, and examples of the emission color include red, green, blue, white, and yellow. The micro-LED is formed from LED elements such as GaAs, GaP, AlGaInP, and InGaN, a sealing resin for sealing the same, a package substrate, electrodes, etc., and the operating temperature is 25 to 60°C.

[0085] <Cured product 3' of the colorless resin composition layer 3 for embedding> The cured product 3' of the colorless resin composition layer 3 for embedding embeds the LED element, the substrate, and the light extraction improvement layer without any gaps, and high transparency and water vapor barrier properties are required. It is important that the refractive index of the cured product of the colorless resin composition layer is 1.51 ± 0.03 as described above, and it is preferable that the difference from the refractive index of the substrate on which the light-emitting element is mounted is as small as possible.

[0086] As described with reference to Fig. 3-1, the thickness T of the cured product 3' of the colorless resin composition layer between the top surface of the LED element 7 and the bottom surface of the water vapor barrier layer 4 1 is preferably 5 to 30 μm, more preferably 7 to 25 μm, and particularly preferably 10 to 20 μm. T 1 When T is 30 μm or less, the transparency can be improved. T 1 When T is 5 μm or more, the uneven shape caused by the top surface of the LED element 7 and the bottom surface of the gap between the LED elements 7 is less likely to affect the surface of the water vapor barrier layer 4, and the water vapor barrier property is enhanced. Being in a more preferable range can satisfy the above-mentioned purpose at a high level. Similarly, when a part of the gap between the LED elements 7 is filled with the cured product 9' of the colored resin composition layer as shown in Fig. 3-2, the thickness T of the cured product 3' of the colorless resin composition layer between the top surface of the LED element 7 and the bottom surface of the water vapor barrier layer 4 1 is preferably in the range as described above. The same applies to the cases of Figs. 2(3) to (5).

[0087] <Water vapor barrier layer 4> As shown in Figs. 3-1 and 3-2, the thickness T of the water vapor barrier layer 4 in the LED encapsulation member 8 2 is as described above. Furthermore, the thickness T of the cured product 3' of the colorless resin composition layer 1 and the thickness T of the water vapor barrier layer 4 2The combined thickness is preferably 5 to 50 μm, more preferably 7 to 30 μm, and even more preferably 10 to 15 μm. Being in the more preferable range enables sealing the LED element and the substrate in the member while maintaining high-level water vapor barrier properties and transparency and satisfying the thinness required for the display.

[0088] <Cured product 9' of the colored resin composition 9 for embedding> As the colored resin composition 9 for embedding, similar to the case of the colorless resin composition layer 3 described above, a coating solution containing at least the resin (A) and the polymerization initiator (C) and further containing a black pigment or a white pigment can be used after being coated and dried to form a sheet. Representative black pigments include carbon black, and representative white pigments include titanium oxide and zinc oxide. Based on FIG. 10, various methods for forming the cured product 9' of the colored resin composition between the light-emitting elements 7 will be described. For example, as shown in FIGS. 10(1-a) and (1-b), after embedding a sheet of the colored resin composition 9 having a sufficient thickness compared to the height of the light-emitting element 7 into the gap between the light-emitting elements 7 in the sealing target β1 by pressing or the like, it is cured as shown in FIG. 10(1-c). Next, the cured product 9' is removed to approximately the same height as the light-emitting element 7 by laser etching, chemical etching, polishing, etc., and a sealing target β3 (see FIG. 9) as shown in FIG. 10(1-d) can be obtained. Furthermore, by thinning or excavating the cured product 9' in the gap between the light-emitting elements 7, a sealing target β2 (see FIGS. 5 to 6) as shown in FIGS. 10(1-e) and 10(1-f) can be obtained. Laser etching is excellent in processing accuracy, and chemical etching is excellent in productivity. In the case of micro-LED elements that require fine processing, laser etching is more preferable.

[0089] Alternatively, as shown in Fig. 10(2-a), a sheet of a colored resin composition 3 that is relatively thin compared to the height of the light-emitting element 7 is placed on the upper surface of the light-emitting element 7, and by using a vacuum forming method such as TOM forming, the colored resin composition 3 can be arranged along the surfaces of the light-emitting element 7 and the substrate 6 as shown in Fig. 10(2-b). After curing the resin composition as shown in Fig. 10(2-c), a sealing target β2 (see Fig. 7) as shown in Fig. 10(2-d) or Fig. 10(2-d’) can be prepared by laser etching, chemical etching, polishing, or the like.

[0090] Also, a sealing target β2 in a form where the cured product 9’ of the colored resin composition is located in the gap of the light-emitting element 7 but hardly touches the side surface of the light-emitting element 7, as shown in Fig. 8, can be obtained, for example, by using the laser lift-off method. That is, as shown in Fig. 10(3-a), a colored resin composition 9 of a desired size is placed on the release film at a position corresponding to the gap of the light-emitting element 7. Next, as shown in Fig. 10(3-b), after bringing the colored resin composition 9 into contact with the substrate 6 in the gap of the light-emitting element 7, a laser is irradiated from behind the release film to detach the colored resin composition 9 from the release film as shown in Fig. 10(3-c). Then, by curing the colored resin composition, a sealing target β2 as shown in Fig. 10(3-d) can be prepared.

[0091] The member 8 in which a plurality of light-emitting elements 7 are sealed can be formed by various methods. For example, as shown in Fig. 4(I-1), a sealing target β1 in which a plurality of light-emitting elements 7 (for example, micro LED elements) are provided on the substrate 6 at a predetermined interval is prepared. Separately, prepare the above-described sealing layer forming sheet 1 as shown in FIG. 4(II). As shown in FIG. 4(III), peel off the first film 2 from the sealing layer forming sheet 1 to expose the colorless resin composition layer 3 for embedding. The peeling method for peeling off the first film 2 from the sealing layer forming sheet 1 is not particularly limited. For example, a roll-shaped sealing layer forming sheet 1 is prepared and peeled off in a roll-to-roll manner while feeding out the sealing layer forming sheet 1 and winding up only the first film 2 at the same time.

[0092] Next, as shown in FIG. 4(IV), place the exposed colorless resin composition layer 3 so as to directly cover the upper surface of the micro LED element 7 in the object β1 to be sealed. In step (IV), in order to prevent a gap from occurring at the contact surface between the upper surface of the micro LED element 7 and the colorless resin composition layer 3, and in order to embed the colorless resin composition layer 3 so that no gap enters between the micro LED elements 7 in the next step, it is preferably carried out under vacuum or reduced pressure. Also, in order to increase the fluidity of the colorless resin composition layer in the next step, it is preferably pre-heated in step (IV). The heating temperature is preferably 10°C or higher, more preferably 30°C or higher, from the Tg of the resin composition. That is, from the Tg of the resin composition described later, 30 to 200°C is preferable, 40 to 150°C is more preferable, 50 to 130°C is further preferable, and 60 to 110°C is most preferable. Then, as shown in FIG. 4(V-1), the colorless resin composition layer 3 is caused to flow by pressing and filled between the micro LED elements 7. It can also be filled around the micro LED element 7. During pressing, it is preferably heated to increase the fluidity of the colorless resin composition layer 3, but if the temperature is too high, the curing of the colorless resin composition layer 3 will progress and prevent filling, so it is preferably at a lower temperature than the next step (VI), that is, at a temperature similar to that in step (IV). From the viewpoint of the filling property of the colorless resin composition layer 3, 30 to 200°C is preferable, 40 to 150°C is more preferable, 50 to 130°C is further preferable, and 60 to 110°C is most preferable.

[0093] As shown in Fig. 4 (VI), active energy rays such as ultraviolet rays or electron beams, or heat can be used to cure the filled colorless resin composition layer 3. In particular, curing by heating is preferred because it is less likely to have light irradiation bias or insufficient irradiation. The heating temperature is preferably a temperature at which curing can be achieved promptly and a temperature at which shrinkage of the water vapor barrier layer 4 can be suppressed, that is, preferably 60 to 250 °C, more preferably 70 °C to 200 °C, still more preferably 80 °C to 150 °C, and most preferably 90 °C to 120 °C. When curing the colorless resin composition layer 3, it can be cured under a pressurized state as in step (V-I), or it can be cured without any particular pressurization. By curing the colorless resin composition layer filled between the micro-LED elements 7 and around the micro-LED elements 7, a cured product 3' of the colorless resin composition layer and a barrier layer 4 seal the sealing target β1, and a member 8 in which a plurality of light-emitting elements are sealed can be obtained.

[0094] Further, at least a part in the depth direction of the individual gaps between the micro-LED elements 7 in the sealing target β1 and / or at least a part of the bottom surface of the individual gaps are filled with a cured product 9' of a colored resin composition for embedding by the method as described above to prepare a sealing target β2 (see Fig. 10). Similar to the case of Fig. 4, using a separately prepared sealing layer forming sheet 1, as shown in Figs. 5 to 8, a cured product 3' of the resin composition layer and a barrier layer 4 seal the sealing target β2, and a member 8 in which a plurality of light-emitting elements are sealed can also be obtained. Furthermore, the individual gaps between the micro-LED elements 7 in the sealing target β1 are filled with a cured product 9' of a colored resin composition for embedding by the method as described above up to the height of the micro-LED elements 7 to prepare a sealing target β3 (see Fig. 10). Similar to the case of Fig. 4, using a separately prepared sealing layer forming sheet 1, as shown in Fig. 9, a cured product 3' of the resin composition layer and a barrier layer 4 seal the sealing target β3, and a member 8 in which a plurality of light-emitting elements 7 are sealed can also be obtained.

[0095] [Examples] Hereinafter, the present disclosure will be specifically described by way of examples and comparative examples, but the present disclosure is not particularly limited to the examples. In the following description, "parts" and "%" represent "parts by mass" and "mass%" respectively unless otherwise specified.

[0096] Production of the solution of resin (A) Production Example 1 [Production Example of (meth)acrylic resin (A-1) solution] Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen inlet tube (hereinafter simply referred to as "reaction vessel"), 80 parts of ethyl acetate, 25 parts of methyl methacrylate, 73 parts of n-butyl methacrylate, 2 parts of acrylic acid, and 0.1 part of 2,2'-azobisisobutyronitrile as an initiator were charged, and the atmosphere in this reaction vessel was replaced with nitrogen gas. Then, while stirring under a nitrogen atmosphere, it was heated to 65°C and polymerized at the same temperature for 4 hours. After that, glycidyl methacrylate in an amount corresponding to half of the carboxyl groups of acrylic acid was added, and it was stirred at 60°C for 24 hours. After completion of the reaction, it was cooled and diluted with ethyl acetate to obtain a solution of (meth)acrylic resin (A-1) having a weight average molecular weight (Mw) of 100,000, a glass transition temperature (hereinafter referred to as Tg) of 50°C, and a solid content of 50%. The measurements of the weight average molecular weight (Mw), Tg, refractive index, water vapor permeability, moisture absorption rate, elastic modulus at 100°C, etc. were determined according to the methods described later.

[0097] Production Example 2 [Production Example of (meth)acrylic resin (A-2) solution] Polymerization was carried out in the same manner as in Production Example 1 except that the amount of 2,2'-azobisisobutyronitrile was changed to 0.3 part. After polymerization, glycidyl methacrylate in an amount corresponding to half of the carboxyl groups of acrylic acid was reacted in the same manner as in Production Example 1 to produce a solution of (meth)acrylic resin (A-2) having a weight average molecular weight (Mw) of 50,000, a Tg of 46°C, and a solid content of 50%.

[0098] Production Example 3 [Production Example of (meth)acrylic resin (A-3) solution] Polymerization was carried out in the same manner as in Production Example 1 except that 0.05 part of 2,2'-azobisisobutyronitrile was used. After polymerization, glycidyl methacrylate equivalent to half the amount of the carboxy group of acrylic acid was reacted in the same manner as in Production Example 1 to produce a solution of (meth)acrylic resin (A-3) having a weight average molecular weight (Mw) of 220,000, a Tg of 52°C, and a solid content of 50%.

[0099] Production Example 4 [Production Example of Solution of (Meth)acrylic Resin (A-4)] The amounts of monomers were 30 parts of methyl methacrylate, 64 parts of n-butyl methacrylate, and 6 parts of acrylic acid. Polymerization was carried out in the same manner as in Production Example 1 except that the initiator was changed to 0.05 part of 2,2'-azobisisobutyronitrile. After polymerization, glycidyl methacrylate equivalent to half the amount of the carboxy group of acrylic acid was reacted in the same manner as in Production Example 1 to produce a solution of (meth)acrylic resin (A-4) having a weight average molecular weight (Mw) of 220,000, a Tg of 55°C, and a solid content of 50%.

[0100] Production Example 5 [Production Example of Solution of (Meth)acrylic Resin (A-5)] The amounts of monomers were 25 parts of methyl methacrylate, 68 parts of n-butyl methacrylate, 2 parts of acrylic acid, and 5 parts of 2-(dimethylamino)ethyl acrylate. Polymerization was carried out in the same manner as in Production Example 1 except that the initiator was changed to 0.15 part of 2,2'-azobisisobutyronitrile. After polymerization, glycidyl methacrylate equivalent to half the amount of the carboxy group of acrylic acid was reacted in the same manner as in Production Example 1 to produce a solution of (meth)acrylic resin (A-5) having a weight average molecular weight (Mw) of 110,000, a Tg of 47°C, and a solid content of 50%.

[0101] Production Example 6 [Production Example of Solution of (Meth)acrylic Resin (A-6)] Polymerization was carried out in the same manner as in Production Example 1 except that glycidyl methacrylate was not reacted with the carboxy group after polymerization, and a solution of (meth)acrylic resin (A-6) having a weight average molecular weight (Mw) of 100,000, a Tg of 48°C, and a solid content of 50% was obtained.

[0102] Production Example 7 [Production Example of Solution of (Meth)acrylic Resin (A-7)] The monomer composition was changed to 98 parts of n-butyl acrylate and 2 parts of acrylic acid, and the initiator was changed to 0.1 part of 2,2'-azobisisobutyronitrile. Polymerization was carried out in the same manner as in Production Example 1. After polymerization, glycidyl methacrylate corresponding to half the amount of the carboxyl group of acrylic acid was reacted in the same manner as in Production Example 1 to obtain a solution of a (meth)acrylic resin (A-7) having a weight average molecular weight (Mw) of 200,000, a Tg of -17°C, and a solid content of 50%.

[0103] Production Example 8 [Production Example of Solution of (Meth)Acrylic Resin (A-8)] Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen inlet tube (hereinafter simply referred to as "reaction vessel"), 80 parts of ethyl acetate, 22 parts of n-butyl acrylate, 76 parts of n-butyl methacrylate, 2 parts of acrylic acid, and 0.1 part of 2,2'-azobisisobutyronitrile as an initiator were charged, and the atmosphere in the reaction vessel was replaced with nitrogen gas. Then, while stirring under a nitrogen atmosphere, the mixture was heated to 65°C to start the reaction. Thereafter, glycidyl methacrylate in an equivalent amount corresponding to half the amount of the carboxyl group of acrylic acid was added in the same manner as in the production of the (meth)acrylic resin (A-1), and the reaction was carried out at 65°C for 4 hours. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate to obtain a solution of a (meth)acrylic resin (A-8) having a weight average molecular weight (Mw) of 200,000, a Tg of 10°C, and a solid content of 50%.

[0104] Production Example 9 [Production Example of Solution of (Meth)Acrylic Resin (A-9)] The monomer composition was 25 parts of methyl methacrylate, 58 parts of n-butyl methacrylate, 15 parts of N-vinyl-2-pyrrolidone (hereinafter also referred to as NVP), and 2 parts of acrylic acid. The initiator was 0.1 part of 2,2'-azobisisobutyronitrile. Except for this, while stirring under a nitrogen atmosphere in the same manner as in Production Example 1, the mixture was heated to 65°C to start the reaction. Thereafter, the reaction solution was reacted at 65°C for 4 hours to complete the reaction, cooled, and diluted with ethyl acetate to obtain a solution of a (meth)acrylic resin (A-9) having a weight average molecular weight (Mw) of 100,000, a Tg of 46°C, and a solid content of 50%.

[0105] [Weight Average Molecular Weight (Mw)] The weight-average molecular weight (Mw) was measured by using the GPC "LC-GPC System" manufactured by Shimadzu Corporation and converting it with polystyrene of known molecular weight as a standard substance to obtain the weight-average molecular weight (Mw). Apparatus name: "Prominence", an LC-GPC system manufactured by Shimadzu Corporation Column: Four GMHXL columns manufactured by Tosoh Corporation and one HXL-H column manufactured by Tosoh Corporation were connected. Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Column temperature: 40 °C

[0106] [Glass transition temperature (Tg: the temperature of the maximum value of tanδ)] The resin solution obtained in each production example was applied onto the release surface of the release film, dried at 100 °C for 2 minutes to prepare a resin sheet with a thickness of 50 μm, cut into a size of 0.5 cm × 2 cm, and the release film was peeled off to obtain a measurement sample. Using a dynamic viscoelasticity measuring device DVA-200 / L2 (manufactured by IT Measurement and Control Co., Ltd.), the dynamic viscoelasticity was measured in a tensile mode at a frequency of 10 Hz, a measurement temperature range of -50 to 150 °C, a heating rate of 5 °C / min, and the storage elastic modulus, loss elastic modulus, and loss tangent (tanδ) were plotted. The peak top temperature (the maximum value of tanδ) of the loss tangent (tanδ) was read from the obtained graph.

[0107] [Colorless resin composition layer for embedding [CR]] [CR-1] to [CR-5] As shown in Table 1, 200 parts of a solution of resins (A-1) to (A-5) with a solid content of 50%, 0.3 part of initiator C-1, and methyl ethyl ketone was added so that the solid content became 40%. It was applied onto the release-treated surface of the first film FA-1 cut into a 15 cm square with an applicator, and the solvent was removed in a drying oven at 80 °C for 5 minutes to obtain colorless resin composition layers [CR-1] to [CR-5] for embedding with a thickness of 10 μm. The measurement of the Tg, refractive index, etc. of the resin composition layer will be described later. Note that the formulations in the table are based on the solid content.

[0108] [CR-6] As shown in Table 1, a colorless resin composition layer [CR-6] with a thickness of 10 μm for embedding was formed on the first film FA-1 in the same manner as in the case of the resin composition layer [CR-1], except that 200 parts of a solution of resin (A-6) with a solid content of 50% and 1 part of initiator C-3 were used.

[0109] [CR-7] to [CR-25], [CR-101] to [CR-107] Colorless resin composition layers for embedding were formed according to the formulations shown in Tables 2 to 4 (expressed in terms of solid content).

[0110] [Other transparent resin solutions] · B-1 Polyester resin (Vylon 200, Mw: 20,000, Tg: 67 °C) and toluene were mixed at a ratio of 1:1 to obtain a polyester resin solution with a solid content of 50%. · B-2 Polyurethane resin (Poly-thick UP, Mw: 60,000, Tg: 20 °C, manufactured by Sanyo Chemical Industries, Ltd.) · Toluene was added to B-3 rubber-based resin (styrene-ethylene-propylene polymer: SEPTON 2063, Mw: 120,000, Tg: 65 °C, manufactured by Kuraray Co., Ltd.) and dissolved with a disper at 60 °C, and then returned to room temperature to obtain a rubber-based resin solution with a solid content of 20%. The Mw and Tg of the above resins were determined in the same manner as in the case of resin (A-1).

[0111] [Initiator and curing agent C] · C-1: Di-t-butyl peroxide (10-hour half-life temperature: 123 °C) · C-2: 1,1-Di(tert-butylperoxy)cyclohexane (10-hour half-life temperature: 84 °C) · C-3: Polyisocyanate (manufactured by Asahi Kasei, Duranate TPA100, HDI nurate form, solid content 100%)

[0112] n [Other additives U] [Production example of dispersion (U-1)] 95 parts of alumina AKP-G07 manufactured by Sumitomo Chemical Co., Ltd. (manufactured by Mitsubishi Chemical Corporation): 10 parts of a resin (A-1) solution with a solid content of 50%, 400 parts of methyl ethyl ketone as a solvent were mixed, and after preliminary dispersion with a disper, using a 0.6 L dyno mill filled with 1800 g of zirconia beads with a diameter of 0.3 mm, the main dispersion was carried out for 2 hours, the zirconia beads were removed, and a dispersion (U-1) of alumina with a solid content of 20% was obtained.

[0113] · (U-2) Urethane acrylate oligomer Mw: 1500 6-functional · (U-3) Urethane acrylate oligomer Mw: 3000 3-functional · (U-4) Ethyleneimine (P1000, manufactured by Nippon Shokubai Co., Ltd.) · (U-5) N-vinyl-2-pyrrolidone (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0114]

Table 1

[0115]

Table 2

[0116]

Table 3

[0117]

Table 4

[0118] [Glass transition temperature (Tg: temperature at the maximum value of tanδ)] The resin composition layers for each embedding were peeled off from the first film FA-1 and measured in the same manner as in the case of resin (A-1).

[0119] [Thickness] The total thickness of the first film FA-1 and each colorless resin composition layer for embedding provided on the first film FA-1 was measured with a thickness gauge (Mitutoyo, measuring head size: 10 mm, measuring force: 1.0 N), and the value obtained by subtracting the thickness of the first film FA-1 from the measured value was taken as the thickness of each colorless resin composition layer for embedding.

[0120] [Refractive index] For the surface of each resin composition layer for embedding provided on the first film FA-1, the value measured at a measurement wavelength of 594 nm in an environment of 25 °C and 50% RH with a prism coupler (Metricon 2010M) was taken as the refractive index.

[0121] [Water vapor transmission rate] <Colorless resin composition layer for embedding> Since it is difficult to isolate the colorless resin composition layer for embedding, the water vapor transmission rate was determined as follows. That is, for the entirety of the first film FA-1 and each colorless resin composition layer for embedding provided on the first film FA-1, using a water vapor transmission rate measuring device C390H manufactured by Labthink, the surface that comes into contact with water vapor during measurement was the surface on the side of the colorless resin composition layer, the transmission area: 5 cm 2 , and at measurement conditions of 40 °C and 90% RH, the value P [g / (m 2 ·day)] of the water vapor transmission rate 24 hours after the measurement was read. Separately, for the first film FA-1, the value P 2 [g / (m 2 ·day)] of the water vapor transmission rate was measured under the same conditions. The value P 3 [g / (m 2 ·day)] of the water vapor transmission rate of the colorless resin composition layer was determined according to the following formula. P 3 =|P × P 2 | / |P 2 - P|

[0122] <Water vapor barrier layer> For the water vapor barrier layer, the water vapor transmission rate was measured alone under the same conditions. <Sealing layer precursor> Regarding the sealing layer precursor, the surface that comes into contact with water vapor during measurement was the surface on the side of the colorless resin composition layer, and the water vapor permeability was measured under the same conditions.

[0123] [Moisture absorption rate] Each resin composition layer for embedding together with the first film FA-1 was cut into a 5 cm square, the first film FA-1 side was placed on a stainless steel plate, left standing at 80 °C for 120 minutes, then taken out into an environment of 23 °C and 50% RH, and after 15 minutes, the mass was measured in the same environment. After that, it was left standing in an environment of 40 °C and 90% RH for 24 hours to absorb moisture, then taken out into an environment of 23 °C and 50% RH, and after 15 minutes, the mass was measured in the same environment. The moisture absorption rate was determined based on the following formula from the mass change before and after moisture absorption. When measuring the mass, the value up to the third decimal place obtained by rounding off the fourth decimal place was recorded. Moisture absorption rate (%) = [(mass after moisture absorption ÷ mass before moisture absorption) - 1] × 100

[0124] [Elastic modulus at 100 °C (Pa)] The value at 100 °C of the plotted storage elastic modulus during Tg measurement.

[0125] [b value] Each resin composition layer for embedding was peeled off from the first film FA-1, laminated onto a glass plate, and measured in transmission mode with a colorimetric color difference meter (ZE6000 manufactured by Nippon Denshoku Industries Co., Ltd., light source: D60) for the entire glass plate to read the b value.

[0126] [HAZE] Each resin composition layer for embedding was peeled off from the first film FA-1, laminated onto a glass plate at room temperature, and measured and evaluated with a haze meter (NDH8000 manufactured by Nippon Denshoku Industries Co., Ltd., light source: D60) for the entire glass plate. Since both the b value and HAZE of the glass plate itself are extremely small, the values measured for the entire glass plate were used as the values for each resin composition layer for embedding.

[0127] <Water vapor barrier layer SB> <SB-1 to SB-6> Cycloolefin resin was fed into a Toyo Seiki plastic mill equipped with a fish blow type T-die with a width of 25 mm at the tip at a cylinder temperature of 230°C, and a cycloolefin film with a thickness of 7 μm and a width of 20 cm was obtained under the conditions of a T-die temperature of 220°C, a discharge rate of 10 g / min, a clearance of the T-die of 30 μm, and a winding speed of 2 m / min. Furthermore, both widths perpendicular (TD) to the flow direction (MD) of the film were cut to obtain a 15 cm square cycloolefin film with a thickness of 7 μm: SB-1. Under the same temperature and discharge conditions, by adjusting the winding speed slower and the clearance of the T-die wider, cycloolefin films with thicknesses of 10 μm: SB-2, 13 μm: SB-3, 20 μm: SB-4, 30 μm: SB-5, and 50 μm: SB-6 were obtained.

[0128] <sb-7>, <SB-101 to SB-103> To 100 g of urethane acrylate (Mw: 2000, 10-functional), 1 g of initiator ESACURE ONE (manufactured by DKSH) and 50 g of methyl ethyl ketone were mixed with a disperser to obtain a coating solution. The coating solution was applied onto a release film with an applicator to a thickness of 30 μm when dried, dried at 80°C for 3 minutes, and cured with an output of 80 W / cm from a high-pressure mercury lamp 2 to obtain a cured film of urethane acrylate with a thickness of 30 μm: SB-7 on the release film. Also, by changing the applicator number during coating, cured films of urethane acrylate with thicknesses of 20 μm: SB-101, 15 μm: SB-102, and 10 μm: SB-103 were obtained.

[0129] · SB-104 Biaxially oriented polypropylene (hereinafter, OPP) film, thickness 20 μm (OPP sheet manufactured by Nanwa Paper Works) · SB-105 Polyethylene terephthalate (hereinafter, PET) film, thickness 12 μm · SB-106 Aluminum oxide vapor-deposited PET film, thickness 12 μm (Barrierox manufactured by Toray)

[0130] The refractive index, water vapor transmission rate, moisture absorption rate, b value, and HAZE were measured under the same apparatus and conditions as in the case of the resin composition layer for embedding. For SB-1 to SB-7, the release film was peeled off to isolate the water vapor barrier layer and then measured. Table 5 shows the refractive index, water vapor transmission rate, etc. of each water vapor barrier layer.

[0131]

Table 5

[0132] [First film FA] · FA-1 KOBATECH RF 40TLGN (manufactured by Kobayashi), thickness 40 μm, Ra: 0.14 μm, Rδc: 0.21 μm · FA-2 KOBATECH RF 40TLSN (manufactured by Kobayashi Co., Ltd.), thickness 40 μm, Ra: 0.31 μm, Rδc: 0.50 μm · FA-3 KOBATECH RF 40TLMN (manufactured by Kobayashi Co., Ltd.), thickness 40 μm, Ra: 1.10 μm, Rδc: 1.52 μm · FA-4 Cosmo Peel E7002 (manufactured by Toyobo Co., Ltd.), thickness 50 μm, Ra: 0.01 μm, Rδc: 0.03 μm · FA-5 PG7H (manufactured by Kogyo Gosei Kogyo Co., Ltd.), thickness 50 μm, Ra: 2.73 μm, Rδc: 4.41 μm

[0133] <Surface roughness Ra, cutting level difference Rδc of the contour curve> The surface roughness Ra in the first film is obtained by extracting a portion of the measurement length L in the direction of the center line from the roughness curve and calculating the arithmetic mean of the absolute value of the deviation between the center line of this extracted portion and the roughness curve. The cutting level difference Rδc of the contour curve is the difference in the height direction of the levels that coincide with any two load length ratios within the roughness curve, and the two load length ratios are defined as 25% and 75%. Specifically, measurement data is acquired using a laser microscope (VK-X100, manufactured by Keyence Corporation), and the acquired measurement data is imported into analysis software (both the analysis application "VK-H1XA" and the surface property measurement module "VK-H1XR" of JIS B0601:2013, both manufactured by Keyence Corporation), and calculated by performing JIS B0601:2013 surface property measurement. In order to obtain the roughness curve from the measured cross-sectional curve obtained by measurement, a λc contour curve filter for removing short wavelengths such as noise and a λs contour curve filter for removing long wavelengths of undulations are used. According to the surface state to be measured, in the surface roughness measurement of the analysis application, either a λs contour curve filter of 2.5 μm, a λc contour curve filter of 0.8 mm, a λs contour curve filter of 8 μm, a λc contour curve filter of 2.5 mm, or a λs contour curve filter of 25 μm and a λc contour curve filter of 8 mm is selected to measure the surface roughness Ra and the cutting level difference Rδc of the contour curve.

[0134] [Second Film FB] · Micro - adhesive film (thickness 60 μm, LE951 manufactured by Toyochem) with an acrylic - based micro - adhesive layer provided on one side of a FB - 1 polyester film, elastic modulus at 100 °C: 1.2×10 9 Pa · FB - 2 polyester film (thickness 50 μm, manufactured by Toray, Lumirror #50), elastic modulus at 100 °C: 9.8×10 8 Pa · Micro - adhesive film (thickness 50 μm, PAC3 - 50 manufactured by Sun Ace Kaken) with an elastomer - based micro - adhesive layer provided on one side of a polyethylene - based film, elastic modulus at 100 °C: 1.9×10 7 Pa · Micro - adhesive film (thickness 50 μm, OPP - SD3 manufactured by Nippa) with a silicone - based micro - adhesive layer provided on one side of a polypropylene - based film, elastic modulus at 100 °C: 2.1×10 8 Pa

[0135] [Example 1] A colorless resin composition layer CR - 1 with a thickness of 10 μm for embedding was provided on the first film FA - 1. Then, the colorless resin composition layer CR - 1 for embedding and the water - vapor barrier layer SB - 2 were laminated at 80 °C to obtain a sealant layer precursor. Next, the water - vapor barrier layer SB - 2 and the micro - adhesive layer side of the second film FB - 1 were laminated at room temperature to obtain a sheet SH - 1 for forming a sealant layer.

[0136] From the sheet SH - 1 for forming a sealant layer, the first film FA - 1 and the second film FB - 1 were peeled off, and the HAZE, b - value, water - vapor permeability, and moisture absorption rate as the sealant layer precursor were determined under the above - mentioned apparatus and conditions. When determining the moisture absorption rate, the water - vapor barrier layer was in contact with the stainless - steel plate. Also, the total light transmittance was measured and evaluated with a haze meter (NDH8000 manufactured by Nippon Denshoku Industries Co., Ltd., light source: D60) in the same manner as HAZE.

[0137] [Examples 2 - 25], [Comparative Examples 101 - 107] As shown in Tables 6 to 8, a colorless resin composition layer for embedding was one of CR-7 to CR-25 and CR-101 to 107, and a water vapor barrier layer was SB-1 or SB-2. Sealing layer forming sheets were obtained in the same manner as in Example 1 except for these.

[0138] [Examples 26 to 29] When forming the colorless resin composition layer CR-1 for embedding, FA-2 to FA-5 were used instead of the first film FA-1, and SB-1 was used as the water vapor barrier layer. Sealing layer forming sheets were obtained in the same manner as in Example 1 except for these.

[0139] [Examples 30 to 32] A colorless resin composition layer CR-1 for embedding was formed on the first film FA-1, SB-1 was used as the water vapor barrier layer, and FB-2 to FB-4 were used instead of the second film FB-1. Sealing layer forming sheets were obtained in the same manner as in Example 1 except for these.

[0140] [Examples 33 to 38], [Comparative Examples 107 to 112] A colorless resin composition layer CR-1 for embedding was formed on the first film FA-1, SB-3 to SB-7 and SB-101 to SB-106 were used instead of SB-2 as the water vapor barrier layer, and FB-1 was used as the second film. Sealing layer forming sheets were obtained in the same manner as in Example 1 except for these.

[0141] [Comparative Examples 113 to 115] Comparative Example 113 has a laminated structure of first film FA-1 / colorless resin composition layer CR-1 for embedding / second film FB-2 without a water vapor barrier layer. Comparative Example 114 has a laminated structure of first film FA-1 / colorless resin composition layer CR-1 for embedding / water vapor barrier layer SB-1 without using a second film. Comparative Example 115 has a laminated structure of first film FA-1 / water vapor barrier layer SB-1 / second film FB-2 without a colorless resin composition layer for embedding. These are sealing layer forming sheets.

[0142] [Evaluation] For the sheets for forming the sealing layer obtained in each example and each comparative example, various performances were evaluated according to the following methods. [Test Substrate] A plate (see Fig. 11(1)) with 10 substantially parallel grooves having a width of 100 μm, a depth of 5 μm, and a spacing of 100 μm drawn in the approximate center of one surface of a glass plate with a size of 25 mm × 25 mm.

[0143] [LED Encapsulation Member Model] The first film was peeled off from the sheet for forming the sealing layer to expose the colorless resin composition layer for embedding, and the colorless resin composition layer for embedding was placed on the surface of the test substrate where the uneven portions were formed. On the second film, a 50-μm-thick TPX (Opulran X-44B, manufactured by Mitsui Chemicals Toagosei Co., Ltd.) as a cushioning material and a 2.0-mm-thick vinyl chloride film (Celeb T, manufactured by Okamoto Co., Ltd.) were placed in order, and pressed at 5 MPa and 100 °C for 20 minutes. After pressing, the second film and the cushioning material were peeled off, and then left standing at 150 °C for 2 hours to cure the colorless resin composition layer for embedding, and a 25-mm square LED encapsulation member model was obtained. In Comparative Example 115, since it did not have a resin composition layer for embedding and the water vapor barrier layer did not adhere to the test substrate, an LED encapsulation member model could not be made.

[0144] [Evaluation of Embeddability] The 10 grooves in the approximate center of the 25-mm square LED encapsulation member model were observed with a microscope at a magnification of 100 times using a coaxial light source from the side of the water vapor barrier layer, and the embeddability was evaluated based on the presence or absence and number of voids less than 10 μm due to poor embedding. In addition, when the maximum diameter of the voids was 10 μm or more, even if there was only one place, it was regarded as a fatal "lifting". S: There were no voids or "lifting", and all the recesses were embedded. A: There were 1 to 5 voids and no "lifting". B: There were 6 to 10 voids and no "lifting". C: There were more than 10 voids, but no "lifting". D: There was one or more "floatings". In Comparative Example 114, since the second film was not laminated, reticular marks occurred on the entire surface of the skin of the mask meringue due to the shrinkage difference of each layer (resin composition layer for embedding, water vapor barrier layer, cushion material) during embedding, so other evaluations were not performed.

[0145] [Evaluation of the smoothness of the top surface] The top surface of the LED encapsulation member model, that is, the surface of the water vapor barrier layer, was observed at 100 times magnification using a laser microscope (Keyence VK-X3000) in a range of 5 mm in length and 7 mm in width in the vertical direction. The line roughness was measured for a range of about 1 mm in length (any three locations) in the direction perpendicular to the grooves of the test substrate in the obtained observation image, and the average height was determined. In addition, irregularities caused by foreign substances other than the irregularities at 100 μm intervals corresponding to the grooves were excluded. S: The average height is 1.0 μm or less A: The average height is 1.1 μm or more and the unevenness difference is 2.0 μm or less B: The average height is 2.1 μm or more and the unevenness difference is 3.0 μm or less C: The average height is 3.1 μm or more and the unevenness difference is 4.0 μm or less D: The average height is 4.1 μm or more

[0146] [Migration resistance] The sheet for forming the encapsulation layer was cut into a size of 2.5 cm in length and 4 cm in width, and further the first film was peeled off to expose the colorless resin composition layer for embedding. It was placed on an evaluation substrate on which a comb-shaped electrode (material: silver plating on copper foil, pattern pitch: 50 μm, L / S = 25 μm / 25 μm, 2.5 cm in length and 5 cm in width) was formed. On the second film, a 50-μm-thick TPX (Opulan X-44B, manufactured by Mitsui Chemicals Toagosei Co., Ltd.) and a 2.0-mm-thick vinyl chloride film (Celeb T, manufactured by Okamoto Corporation) were sequentially placed as cushion materials and pressed at 5 MPa and 100 °C for 20 minutes. After pressing, the second film and the cushion material were peeled off, and then left standing at 150 °C for 2 hours to cure the colorless resin composition layer for embedding, and a test piece for evaluating migration resistance was obtained. After applying a voltage of 30 V or 50 V to the test piece for 1,000 hours in an environment of 85°C and 85% RH, the surface resistance value was measured by applying a probe to the water vapor barrier surface of the sealing layer with a resistivity meter (High Resista UX) at room temperature (23°C), and the number of leak touches during the 1,000 hours was confirmed. Note that "leak touch" means that there is an insulation breakdown due to a short circuit, and the resistance instantaneously decreases and current flows, which means that the insulation property does not deteriorate when there is no leak touch. S: The resistance value is 1×10 8 Ω or more and there is no leak touch. A: The resistance value is 1×10 8 Ω or less and 1×10 7 Ω or more and there is no leak touch. B: The resistance value is 1×10 8 Ω or less and 1×10 7 Ω or more and there is 1 leak touch. C: The resistance value is 1×10 7 Ω or less and 1×10 6 Ω or more and there are 3 or fewer leak touches. D: The resistance value is 1×10 6 Ω or less, or there are 4 or more leak touches.

[0147] The evaluation under the application condition of 30 V assumes the use of the display in a wide range of regions such as temperate, subarctic, arctic, and dry zones, and the evaluation under the application pressure condition of 50 V further assumes the use of the display in tropical regions. In both cases, S can be best used for the formation of high-power large displays of 50 inches or more, A can be preferably used for the formation of large displays, B can be used for the formation of general-purpose displays of less than 50 inches, C can be limitedly used for the formation of small displays of less than 10 inches, and D cannot be used.

[0148] [Yellowing resistance] Using a color difference meter CR-300 (manufactured by Konica Minolta), in accordance with the method described in JIS-Z8722, for the LED sealing member model, the b* value (the value measured from the water vapor barrier layer side) in the L*a*b* color system before and after a heating test of 110°C × 500 hours was obtained respectively, and the yellowing resistance was evaluated by the difference Δb* value. In addition, when the total light transmittance of the LED encapsulation member model is 70% or more, it was measured under transmission conditions, and when the total light transmittance was less than 70%, it was measured under reflection conditions. Δb* value = b* value after heat test - b* value before heat test S: The Δb* value is less than 0.3. A: The Δb* value is 0.3 or more and less than 0.5. B: The Δb* value is 0.5 or more and less than 1.0. C: The Δb* value is 1.0 or more and less than 1.5. D: The Δb* value is 1.5 or more. S can be preferably used for a transparent display, A can be preferably used for applications other than a transparent display, B can be generally used, C can be used limitedly, and D cannot be used.

[0149] [Invisibility of boundary parts, etc.] Four LED encapsulation member models were prepared, and a white X marker was placed at the center of the bottom surface of a black plastic case (Sekisui's Granblock case) with a depth of 23 mm × length of 146 mm × width of 70 mm. As shown in Fig. 11(1), the models were arranged in two layers each in the vertical and horizontal directions so that each side of the model was as parallel as possible to each side of the case. At that time, the intersection of the four models was set at the position of the white marker. Fig. 11(1) is a top view (schematic) when the four models are arranged in the case. Next, silicone oil (Shin-Etsu Silicone's Silicone Oil X-48-1800, refractive index 1.51) was poured from the top surface of the model until it exceeded 3 mm to 5 mm, and the entire model was immersed. Under a fluorescent lamp, as shown in Fig. 11(2), near the center of the short side of the case, 50 cm away from the white marker, three arbitrary persons looked at the models from the short side of the case at an angle of 45°, and confirmed whether the boundary parts between the models and the periphery of the models were visible or not, and evaluated as follows. The lowest evaluation among the three persons was adopted. S: It is not possible to tell whether the four models are present. A: Of the boundary lines of the four models, the boundary line parallel to the short side of the case is visible, but the existence of the other four models cannot be determined. B: Of the boundary lines of the four models, the boundary lines parallel to the long side and the short side of the case appear in a cross shape. C: Not only the cross-shaped boundary line but also the outer periphery of the four models is visible. D: The cross-shaped boundary line, the outer periphery of the four models, and the upper surfaces of the four models are visible. S can be preferably used in a transparent display, A can be used limitedly in a transparent display, B can be preferably used in a high-definition colored display, C can be used in a general-purpose colored display, and D is not suitable for use.

[0150]

Table 6

[0151]

Table 7

[0152]

Table 8

[0153]

Table 9

[0154]

Table 10

[0155]

Table 11

Explanation of Symbols

[0156] 1: Sheet for forming a sealing layer 2: First film 3: Colorless resin composition layer for embedding 3‘: Cured product of the colorless resin composition layer for embedding 4: Water vapor barrier layer 5: Second film 6: Substrate 7: Light-emitting element, LED element 8: Member in which a plurality of light-emitting elements are encapsulated 9: Colored resin composition for embedding 9’: Cured product of the colored resin composition for embedding α: Encapsulation layer precursor β1, β2, β3: Objects to be encapsulated

Claims

1. A sheet for forming a sealing layer for filling spaces between light-emitting elements for a display using a plurality of light-emitting elements as a light source and for covering a surface of the light-emitting elements from which the light is emitted, The sealing layer-forming sheet includes a first film 2, a sealing layer precursor α, and a second film 5 arranged in this order, The sealing layer precursor α has a water vapor permeability of 100 [g / (m 2 - 24 hours)], moisture absorption rate is 1.5 mass% or less, The sealing layer precursor α has a refractive index of 1.51±0.03 and a water vapor permeability of 100 [g / (m 2 24 hours)] or more, and a colorless resin composition layer 3 for embedding having a refractive index of 1.53±0.03 and a water vapor permeability of 100 [g / (m 2 - 24 hours)], Sheet for forming sealing layer.

2. The sheet for forming a sealing layer according to claim 1 , wherein the water vapor barrier layer 4 is a thermoplastic olefin film.

3. Tensile storage modulus E'3 of the colorless embedding resin composition layer 3 at 100°C (100) , the tensile storage modulus E'4 of the water vapor barrier layer 4 (100) , tensile storage modulus E'5 of second film 5 (100) The sheet for forming a sealing layer according to claim 1 , wherein the following relationship is satisfied: E'4 (100) / E'3 (100) is between 100 and 1000 and E'5 (100) / E'4 (100) 0.5 to 3

4. The sheet for forming a sealing layer according to claim 1 , wherein the sealing layer precursor α has a total light transmittance of 85% or more.

5. A substrate and a plurality of light emitting elements mounted on the substrate at intervals, At least a portion of the depth direction of the gap between the light emitting elements has a refractive index of 1.51±0.03 and a water vapor permeability of 100 [g / (m 2 24 hours)] or more of the cured product 3' of the colorless resin composition 3 for embedding, The side from which the light of the multiple light-emitting elements are emitted is made of the cured material 3′ and a material having a refractive index of 1.53±0.03 and 100 [g / (m 2 - 24 hours)] and a water vapor barrier layer 4, A member in which multiple light emitting elements are sealed.

6. A component in which multiple light-emitting elements are sealed, as described in claim 5, wherein at least a portion of the depth direction of each gap between the light-emitting elements and / or at least a portion of the bottom surface of each gap is filled with a cured product 9' of a colored resin composition 9 for embedding, and the remaining portions of each gap between the light-emitting elements are filled with a cured product 3' of a colorless resin composition 3 for embedding.

7. 6. The member in which a plurality of light emitting elements are encapsulated according to claim 5, wherein the water vapor barrier layer 4 is a thermoplastic olefin film.

Images