Sealing sheet and method for manufacturing the same, and display having a resin composition layer

Abstract

To provide a sealing sheet, a method for manufacturing the same, and a display using the same, which are less prone to thickness variations and appearance defects at the edges of the resin composition layer, and less prone to voids at the bottom surface of recesses and corners. [Solution] A sealing sheet for sealing an optical semiconductor used in a display that uses an optical semiconductor as a light source, wherein the sealing sheet comprises a first film and a resin composition layer for forming a sealing layer laminated directly on the first film, the shrinkage rate of the first film measured under the conditions described in the specification is 1.2% or less, and the storage modulus of the first film at 150°C in tensile mode is E' 150 [×10 8 Pa], the thickness of the first film is T l When [μm], 40 ≤ (E' 150 ) 1 / 2 ×T l The peel force P between the first film and the resin composition layer satisfies ≤230. l A sealing sheet having a density of 8-150 mN / 25 mm and a first film thickness T1 of 20-120 μm.

Description

Technical Field

[0001] The present disclosure relates to a sealing sheet, and more specifically, to a sealing sheet including a resin composition layer for sealing micro Light Emitting Diodes (hereinafter abbreviated as LEDs) used in a display using the micro LEDs as a light source, a manufacturing method thereof, and a display having a sealing layer formed from the resin composition layer.

Background Art

[0002] In recent years, displays (display panels) 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, quantum dots, etc., displays using optical semiconductors such as mini / micro LEDs and organic ELs, plasma displays, electrophoretic displays, etc. are being studied. And these displays are being considered for wide use from large display applications such as signage and TVs to small sizes such as tablets, personal computers, smartphones, wearable devices, etc. In particular, the development of displays using micro LEDs has been increasingly advanced, and the development of a sealing sheet for sealing a plurality of LED elements has attracted attention. Patent Document 1 proposes a semiconductor sealing sheet containing an epoxy resin and characterized by performing a filling step at 65°C and a heat aging step at 150°C. According to the sealing material of this document, it is described that the shrinkage of the resin can be suppressed by adding an inorganic filler. Patent Document 2 proposes a dry film for optical semiconductor sealing. According to the sealing material of this document, it is described that warpage is suppressed and burrs and chipping during dicing can be suppressed by setting the maximum diameter of the aggregated particles of the inorganic filler to be half or less of the thickness of the resin composition layer. Patent Document 3 proposes a sheet for encapsulating an optical semiconductor device, which includes a diffusion layer and an antireflection layer. According to the encapsulant in this document, by controlling the total light transmittance and haze value of the diffusion layer and the antireflection layer to have a specific relationship, it is described that an optical semiconductor device with improved antireflection function and contrast for metal wiring and the like, while reducing color cast, can be manufactured.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, with the increasing demand for larger displays, methods of manufacturing a single large panel by arranging and joining multiple display panels have attracted attention. Furthermore, the required functions vary widely depending on the type of display. Development of sealing sheets for encapsulating the optical semiconductors placed in these displays is progressing daily, but while conventional technologies offer excellent heat resistance, impact resistance, and embedding properties, they sometimes have the following problems: After the sealing sheet undergoes a heat press and heat aging process, shrinkage of the first film can cause uneven thickness at the edges of the resin composition layer, resulting in noticeable panel seams when multiple display panels are arranged and joined together (hereinafter also referred to as seamlessness). In addition, the rigidity of the first film can impair the embedding properties of the sealing sheet (hereinafter also referred to as embedding properties). Moreover, when the sealing sheet is heat pressed, the pattern on the top plate of the heat press machine can be transferred to the resin composition layer, and when the first film is peeled off after the heat aging process, zipping marks can remain on the resin composition layer, resulting in a poor appearance and contributing to low yield.

[0005] The present disclosure aims to provide a sealing sheet, a method for manufacturing the same, and a display using the same, which are less prone to thickness unevenness at the edges of the resin composition layer, less prone to appearance defects, and less prone to voids at the bottom surface of recesses and corners. [Means for solving the problem]

[0006] As a result of diligent research to solve the above problems, the Disclosing Parties have arrived at the inventions described in [1] to

[10] below. In other words, [1]: A sealing sheet for sealing an optical semiconductor used in a display that uses an optical semiconductor as a light source, wherein the sealing sheet comprises a first film and a resin composition layer for forming a sealing layer laminated directly on the first film, and the shrinkage rate of the first film measured under the following conditions is 1.2% or less: The first film in an unheated state is heat-treated at 150°C for 120 minutes, and the shrinkage rate of the first film in the longitudinal direction after the heat treatment is measured, and the storage modulus of the first film at 150°C in tensile mode is E' 150 [×10 8 Pa], the thickness of the first film is T l When the value is [μm], the following equation (1) is satisfied, and 40 ≤ (E' 150 ) 1 / 2 × T l ≤ 230 (1), peel force P between the first film and the resin composition layer l The sealing sheet is characterized in that the current is 8-150 mN / 25 mm and the thickness T1 of the first film is 20-120 μm.

[0007] [2]: The sealing sheet according to [1], characterized in that the first film is a biaxially oriented polyester film or a biaxially oriented polyolefin film. [3]: The sealing sheet according to [1] or [2], characterized in that the shrinkage rate of the first film is 1.0% or less. [4]: The sealing sheet according to any one of [1] to [3], characterized in that the first film is an annealed product. [5]: The sealing sheet according to any one of [1] to [4], characterized in that the resin composition layer contains at least one selected from the group consisting of (meth)acrylic resin, epoxy resin, and urethane resin. [6]: The sealing sheet according to [5], characterized in that it contains 50% or more (meth)acrylic resin when the solid content of the resin composition layer is 100% by mass. [7]: The sealing sheet according to any one of [1] to [6], characterized in that the optical semiconductor is a microLED.

[0008] [8]: A display including a sealing layer which is a cured product of the resin composition layer according to any one of [1] to [7].

[0009] [9]: A method for manufacturing a sealing sheet for sealing an optical semiconductor used in a display having the optical semiconductor as a light source, wherein the sealing sheet includes a first film and a resin composition layer for forming a sealing layer laminated directly above the first film, and the shrinkage rate of the first film measured under the following conditions is 1.2% or less: The first film in the unheated state is heat-treated at 150 °C for 120 minutes, and the shrinkage rate in the longitudinal direction of the first film after the heat treatment is measured. The first film has a storage elastic modulus E’ 150 [×10 8 Pa] when the following formula (1) is satisfied, 40 ≦ (E’ 150 ) 1 / 2 × T l ≦ 230 (1), the peeling force P l between the first film and the resin composition layer is 8 to 150 mN / 25 mm, and the first film thickness T1 is 20 to 120 μm. A method for manufacturing a sealing sheet, characterized by this.

[10] : The method for manufacturing a sealing sheet according to [9], wherein the first film is subjected to annealing treatment. [Effect of the Invention]

[0010] According to the present disclosure, it has become possible to provide a sealing sheet, a method for manufacturing the same, and a display using the same, in which thickness unevenness hardly occurs at the end of the resin composition layer for sealing, appearance defects hardly occur, and voids hardly occur at the bottom surface or corner portions of the recesses. [Brief Description of the Drawings]

[0011] [Figure 1] It is a schematic cross-sectional view showing an example of the laminated structure of the sealing sheet. [Figure 2] It is a schematic cross-sectional view showing a process of sealing an optical semiconductor element on a substrate having a light-emitting element. [Figure 3]This is a schematic diagram illustrating the method for evaluating the shrinkage rate in the first film MD direction. [Figure 4] This is a schematic diagram illustrating the method for evaluating seamlessness in the embodiment. [Figure 5] This is a cross-sectional view showing an example of a test board that mimics a micro-LED substrate. [Modes for carrying out the invention]

[0012] The present disclosure will be described in detail below. The embodiments described below are examples of the present disclosure. The present disclosure is not limited to the embodiments described below and includes modifications that do not alter the essence of the present disclosure. In this specification, numerical ranges specified using "~" include the numbers before and after "~" as the lower and upper limits. In numerical ranges described in stages in this specification, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. Furthermore, (meth)acrylic acid refers to either acrylic acid or methacrylic acid, or both. Unless otherwise noted, each component mentioned herein may be used individually or in combination of two or more. When using two or more components in combination, the total content should be used.

[0013] [Form of sealing sheet] As shown in Figure 1(a), the sealing sheet of this disclosure comprises a first film 12 and a resin composition layer 11 for forming a sealing layer, which is laminated directly on the first film 12. The first film 12 may be a low-shrinkage film. Multiple resin composition layers 11 may be provided. When adopting the two-layer structure shown in Figure 1(a), a manufacturing method in which the resin composition layer 11 is formed on the first film 12 is preferred. Alternatively, as shown in Figure 1(b), a three-layer structure may be adopted in which a first film 12, a resin composition layer 11 for forming a sealing layer laminated directly on the first film 12, and a second film 13 are laminated in this order. In this case as well, multiple layers of resin composition layer 11 can be provided. When adopting the three-layer structure shown in Figure 1(b), the resin composition layer 11 can be formed on the second film 13 and then the first film 12 can be laminated, or the resin composition layer 11 can be formed on the first film 12 and then the second film 13 can be laminated, with the latter manufacturing method being preferred. A sealing sheet roll can be obtained by winding the sealing sheet onto a core in a roll shape after manufacturing the sealing sheet, or while manufacturing the sealing sheet. The winding length can be designed according to the application. From the viewpoint of increasing productivity, the winding length is preferably 50m or more, and more preferably 100m or more. From the viewpoint of manufacturing yield, the winding length is preferably 10,000m or less. When the sealing sheet is in roll form, it is preferable to place the first film on the inside of the winding.

[0014] The sealing sheet of this disclosure is used to seal between elements of a display that uses multiple optical semiconductors as light sources. MicroLEDs are preferred as the optical semiconductors, and their emission colors are not particularly limited, but examples include red, green, and blue emission colors. The sealing sheet of this disclosure is preferably used to seal a microLED array in which a large number of the three color elements are regularly arranged on a substrate. That is, the sealing sheet of this disclosure is preferably used for sealing between red (R) elements and green (G) elements, between G elements and blue (B) elements, between B elements and R elements, and for sealing between [R element, G element, B element] units. The resin composition layer is preferably sealed by directly adhering it to the micro-LED. The micro-LED is not particularly limited, but is preferably placed on a substrate such as acrylic, urethane, polycarbonate, epoxy, polyimide, glass, paper, cloth, aluminum, resist, ceramic, or polyethylene terephthalate, and has electrode portions.

[0015] Because the resin composition layer has high conformability to uneven surfaces, it is suitable for use in a manner that follows the micro-LEDs and fills the spaces between them. By filling the spaces between the micro-LEDs with the resin composition layer, a sealing layer (cured product) made of the resin composition layer is formed. The sealing layer has the function of fixing adjacent micro-LEDs and preventing them from falling off. In particular, it is even more preferable to use the resin composition layer as a sealing layer for a micro-LED display panel. Furthermore, the sealing layer may have other functionalities. Specific examples include sealing layers having light diffusion prevention, light shielding, shielding, light leakage prevention, low shrinkage, wavelength conversion, light reflectivity, high refractive index, low refractive index, and heat dissipation properties. In this disclosure, the term "resin composition layer" refers to all layers formed by the resin (A) described later, and can refer to any of the following: a layer formed on the first film or any other support, a single layer, or a layer used to seal multiple optical semiconductor elements. On the other hand, the term "sealing layer" specifically refers to the layer formed when the resin composition layer is used to seal multiple optical semiconductor elements. Furthermore, in this specification, the sealing sheet relating to this disclosure may include an unheated state (before heat treatment) and a heated state (during and after heat treatment). That is, both the first film and the resin composition layer (for forming the sealing layer) in this disclosure may include an unheated state (before heat treatment) and a heated state (during and after heat treatment). Therefore, the sealing layer described above can be said to be a form (cured product) of the resin composition layer. MicroLEDs are tiny optical semiconductors with a diameter of 50 μm or less, or 100 μm or less. By mounting multiple microLEDs on a substrate with wiring and circuits, a display is formed that uses multiple optical semiconductors as light sources. MicroLEDs are formed from optical semiconductors such as GaAs, GaP, AlGaInP, and InGaN, a resin composition layer to encapsulate them, a package substrate, electrodes, etc., and their operating temperature is 25 to 60°C. Below, an example of the process for forming the resin composition layer will be explained using Figure 2. Although not shown in the diagram, a step prior to step (a) shown in Figure 2 may be provided to prepare a substrate to be sealed, in which multiple microLEDs are arranged on one side of the substrate at intervals from each other.

[0016] Process (a): Placing of sealing sheet As shown in Figure 2(a), the surface of the sealing sheet according to this disclosure with the exposed resin composition layer 11 is placed on a substrate 21 having a plurality of micro-LED elements 20 so as to directly cover the entire plurality of micro-LED elements 20. In this specification, the number of microLED elements 20 is not particularly limited. In display applications, the number of microLED elements 20 used is determined by the display size and the number of pixels. The micro-LED element 20 has a thickness of 100 μm or less and a planar area of ​​40,000 μm². 2 The following are preferred: a thickness of 50 μm or less and a planar area of ​​10,000 μm². 2 The following are more preferable: a thickness of 20 μm or less and a planar area of ​​2,500 μm². 2 The following are even more preferable. The spacing between micro-LED elements 20 mounted on the substrate 21 is, for example, 10 to 5,000 μm. When red, green, and blue micro-LED elements 20 are mounted on the substrate 21 as a set of 1 pixel, the spacing between pixels is, for example, 10 to 2,000 μm, preferably 20 to 1,800 μm, and more preferably 500 to 1,500 μm. The spacing between micro-LED elements 20 within a single pixel is, for example, 10 to 200 μm, preferably 10 to 100 μm, and more preferably 20 to 60 μm.

[0017] Process (b): Filling process As shown in Figure 2(b), for example, the resin composition layer 11 is made to flow by pressing and fill the area around the micro-LED elements 20 and between the micro-LED elements 20. The resin composition layer 11 that fills the area around the micro-LED elements 20 and between the micro-LED elements 20 becomes a sealing layer. The pressing method is not particularly limited, but hot pressing and vacuum pressing are preferred. From the viewpoint of filling the resin composition layer 11, the pressing temperature is preferably 20 to 200°C, more preferably 30 to 150°C, even more preferably 50 to 140°C, and most preferably 70 to 130°C. It is also possible to perform the filling process after peeling off the first film 12. However, it is preferable that the first film 12 is laminated on the resin composition layer during the filling process, as this suppresses the transfer of the pattern on the press machine top plate to the resin composition layer, thereby enabling the formation of a uniform resin composition layer.

[0018] Process (c): Heating and aging process To improve adhesion with the micro-LED element 20 and the substrate 21, heating aging may be performed after pressing, as shown in Figure 2(c). The heating temperature is preferably 40 to 250°C, more preferably 80 to 220°C, and even more preferably 100 to 190°C. The heating time is preferably 30 to 300 minutes, more preferably 60 to 240 minutes, and even more preferably 90 to 180 minutes. By using the above heating temperature and heating time, residual stress in the resin composition layer 11 can be removed, improving adhesion. The first film 12 or the first film 12' after heating may be peeled off before heating aging or after heating aging, but it is more preferable to peel it off after heating aging. Heating aging may be performed after steps (d-1) and (d-2) described later. If steps (d-1) and (d-2) are performed before heating aging, it is preferable to peel off the first film 12 or the first film 12' after heating before the etching process.

[0019] Process (d-1) or (d-2): Etching process In step (d-1) or (d-2), etching may be performed as needed to remove or thin the resin composition layer 11 or the cured resin composition layer 11' on the micro-LED element 20. When performing step (d-1) or (d-2), it is preferable to do so after peeling off the first film 12 or the first film 12' after heating. By removing the excess resin composition layer 11 or the cured resin composition layer 11', the brightness of the micro-LED element 20 is improved and visibility during illumination is ensured. The thickness of the resin composition layer 11' after etching and heating is preferably about the same as the thickness of the micro-LED element 20, as shown in Figure 2(d-1), or less than or equal to the thickness of the micro-LED element 20, as shown in Figure 2(d-2). In other words, the difference between step (d-1) and step (d-2) is the difference in the amount of etching. Note that it is not necessary to completely remove the cured resin composition layer 11' from the micro-LED element 20; it is sufficient if it is substantially removed, and it is acceptable if a small thin film remains. Furthermore, if sufficient brightness can be ensured, steps (d-1) and (d-2) may be omitted. The etching method is not particularly limited, but preferred examples include wet etching methods such as chemical polishing using chemical agents, physical polishing using abrasives, laser etching, plasma etching using argon plasma or oxygen plasma, and dry etching methods such as ion beam etching. From the viewpoint of reducing surface irregularities, plasma etching or a combination of wet etching and dry etching methods is preferred. Furthermore, for plasma etching conditions, for example, dry etching can be performed using an anisotropic plasma apparatus with a mixed gas of CF4 / O2 / N2, at an output of 1500-3000W and for 180-600 seconds. In this case, the gas supply rate of CF4 should be, for example, 50-100 sccm, the gas supply rate of O2 should be, for example, 500-1000 sccm, and the gas supply rate of N2 should be, for example, 50-100 sccm.

[0020] As described above, a sealing layer can be formed from the resin composition layer in the sealing sheet of this disclosure by going through steps (a) to (d-1) or steps (a) to (d-2). Multiple layers may be laminated by repeating the above steps. As described above, the sealing sheet of this disclosure comprises a first film and a resin composition layer (dried or solidified) for forming a sealing layer laminated directly above it. It can be obtained by coating the first film with a coating liquid of the resin composition for forming the resin composition layer and drying it. Furthermore, in the case of a three-layer structure in which a first film, a resin composition layer for forming a sealing layer laminated directly on the first film, and a second film are laminated in this order, this can be achieved by coating the first film with a coating liquid of the resin composition for forming the resin composition layer, drying it, and then covering the surface of the resin composition layer with the second film, or by coating the second film with a coating liquid of the resin composition for forming the resin composition layer, drying it, and then covering the surface of the resin composition layer with the first film.

[0021] [First Film] Examples of the first film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin films such as polypropylene and polyethylene; polyvinyl chloride films; polyurethane films; nylon films; polyolefin films; triacetylcellulose films; and cycloolefin films. From the viewpoint of handling, polyester films and polyolefin films are preferred. From the viewpoint of low heat shrinkage, biaxially oriented polyester films and biaxially oriented polyolefin films are preferred, with biaxially oriented polyester films being more preferred. Furthermore, it is preferable that the first film has a release layer on the surface in contact with the resin composition layer, as will be described later. Examples of biaxially oriented polyester films with a release layer include the Therapeal series from Toray Film Processing Co., Ltd., the Cosmopeel series from Toyobo Co., Ltd., the Separator SP-PET series from Mitsui Chemicals ICT Materia Co., Ltd., and the Unipeel series from Unitika Ltd.

[0022] Furthermore, in the sealing sheet relating to this disclosure, the shrinkage rate of the first film measured under the following conditions is 1.2% or less. That is, the shrinkage rate of the first film is determined by heat-treating the unheated first film at 150°C for 120 minutes, and then measuring the shrinkage rate of the obtained first film in the longitudinal direction (MD direction) after the heat treatment. Here, even if a film has a longitudinal shrinkage rate exceeding 1.2% when heated at 150°C for 120 minutes, if the shrinkage rate can be reduced to 1.2% or less through the annealing treatment described later, the treated film can be used as the first film. Of course, the shrinkage rate can be further reduced by annealing a film with a shrinkage rate of 1.2% or less. In this specification, the MD direction refers to the machine direction in the manufacturing of film products such as the first film, and is the longitudinal direction of the film. On the other hand, the TD direction (Transverse direction) refers to the width direction or transverse direction of the film. Typically, in film products, the shrinkage rate in the MD direction of the film is greater than the shrinkage rate in the TD direction. In particular, biaxially oriented films are prone to thermal shrinkage in the MD direction, making the thermal shrinkage rate in the MD direction important.

[0023] As described above, in the filling process (b) and the heating aging process (c) in Figure 2, the first film 12 is placed on the upper side of the resin composition layer 11 (i.e., the side that does not come into contact with the substrate 21 or the micro-LED element 20). Therefore, it is important that the first film 12 does not shrink as much as possible during the filling process (b) and the heating aging process, especially during the heating aging process (c). If the first film 12 shrinks significantly during the heating aging process (c), deformation is likely to occur at the edges of the resin composition layer during curing or at the edges of the sealed layer after curing, making the seams of the panels more noticeable when multiple display panels are lined up and joined together. In addition, if the first film becomes wavy due to thermal shrinkage, the wavy will be transferred to the sealed layer after curing, which can impair the appearance, such as causing distortion in the image when incorporated into a display.

[0024] Thus, in step (c) shown in Figure 2 of this disclosure, the thermal shrinkage of the first film 12 on the side of the resin composition layer that does not come into contact with the optical semiconductor element (micro LED element 20) is important, and especially when a biaxially oriented film is used, thermal shrinkage in the MD direction is likely to occur, so the thermal shrinkage rate in the MD direction is important. Therefore, as the first film constituting the sealing sheet of this disclosure, a film with a thermal shrinkage rate in the MD direction of 1.2% or less after a heating aging process at 150°C for 2 hours (120 minutes) is used. By using a film with a thermal shrinkage rate in the MD direction of 1.2% or less as the first film, excessive shrinkage of the first film during the heating aging process can be prevented. This makes deformation of the resin composition layer edges that occurs with the shrinkage of the first film less likely to occur, and makes the seams of panels less noticeable when multiple display panels are lined up and joined together. Furthermore, by using a first film with a thermal shrinkage rate in the MD direction of 1.2% or less, the generation of waviness in the first film due to thermal shrinkage can be suppressed, resulting in a good appearance of the sealing layer after curing. In other words, a first film with a thermal shrinkage rate in the MD direction of 1.2% or less is important in suppressing deformation of the resin composition layer edges and suppressing waviness. From a similar viewpoint, with respect to the first film, the thermal shrinkage rate in the MD direction is preferably 1.0% or less, more preferably 0.7% or less, and even more preferably 0.3% or less.

[0025] Annealing is an effective means of providing such a low-shrinkage film. In other words, the shrinkage rate of the first film described above can be adjusted by annealing. There is no particular method for annealing, but in the case of a film, examples include leaving the film in a high-temperature environment, transporting the film in a high-temperature environment, or bringing a high-temperature jig into contact with the film. By increasing the annealing temperature or increasing the heating time, the thermal shrinkage rate of the film after treatment can be reduced compared to the thermal shrinkage rate of the film before treatment. Thus, it is preferable that the first film is an annealed product that has undergone annealing treatment.

[0026] The annealing temperature is preferably 100°C to 210°C. From the viewpoint of reducing the thermal shrinkage rate in the MD direction, it is preferably 105°C or higher, more preferably 120°C or higher, and even more preferably 150°C or higher. From the viewpoint of maintaining the shape stability and peel strength of the first film after treatment, it is preferably 200°C or lower, and even more preferably 190°C or lower. Furthermore, the annealing time is preferably 30 seconds to 60 minutes. From the viewpoint of uniformity of the annealing process and reducing the thermal shrinkage rate of the first film in the MD direction after processing, 45 seconds or more is preferable, 1 minute or more is more preferable, and 2 minutes or more is even preferable. From the viewpoint of shape stability of the first film and maintenance of peeling force, 50 minutes or less is preferable, 45 minutes or less is more preferable, and 30 minutes or less is even preferable. Based on the above, the first film is more preferably an annealed biaxially oriented polyester film and an annealed biaxially oriented polyolefin film, and even more preferably an annealed biaxially oriented polyester film.

[0027] The first film preferably has a release layer on the surface facing the resin composition layer. The release layer is preferably formed by applying a release agent such as silicone resin, alkyd resin, fluororesin, or melamine resin to the film, and a release layer using silicone resin is more preferable from the viewpoint of handling (prevention of separation). Peeling force P between the first film and the resin composition layer l The peeling force P of the first film is 8 mN / 25 mm or more. l By setting the peel force to 8mN / 25mm or higher, handling performance can be improved. Furthermore, it is possible to suppress the occurrence of appearance defects such as marks remaining at the peeled areas due to partial delamination of the resin composition layer and the first film during the heating aging process, and also suppress deformation of the resin composition layer. (Peel force P of the first film) l The peeling force P of the first film is preferably 10 mN / 25 mm or more, and more preferably 20 mN / 25 mm or more. l By setting the peeling force P of the first film to 150 mN / 25 mm or less, zipping during peeling of the first film after the heating aging process can be suppressed, thereby preventing defects in the appearance of the resin composition layer. l The value is preferably 120 mN / 25 mm or less, and more preferably 100 mN / 25 mm or less. First film peeling force P lThis can be adjusted by the release treatment of the release layer. For example, it can be adjusted by the type of release agent, the amount of release agent applied, and the surface roughness of the release layer. To decrease the release force, for example, treatments such as increasing the surface roughness or increasing the amount of release agent applied are effective, and to increase the release force, the opposite adjustments should be made. First film peeling force P l This can be measured, for example, by attaching the resin composition layer of the sealing sheet to a SUS plate, and then peeling off the first film from the resin composition layer at a peeling angle of 180° and a peeling speed of 300 mm / min in an environment of 23°C and 50% relative humidity. The first film may have a functional layer in addition to the release layer. Specific examples of functional layers include an antistatic layer and an anti-blocking layer.

[0028] Thickness T of the first film l The thickness is 20 μm or more. This controls the transfer of the waviness of the first film to the resin composition layer, and also suppresses the transfer of the pattern of the press machine upper plate to the resin composition layer during the filling process, thereby enabling the formation of a uniform resin composition layer. Thickness T of the first film l The particle size is preferably 25 μm or larger, and more preferably 35 μm or larger. Also, the thickness T of the first film l The thickness is 120 μm or less. This allows the first film to appropriately follow the deformation of the resin composition layer into the voids during the filling process, and also controls the pressure transmission applied to the resin composition layer, resulting in uniform flow of the resin composition layer, which in turn provides good embedding properties and adhesion to the substrate. Thickness T of the first film l The particle size is preferably 90 μm or less, and more preferably 80 μm or less. Furthermore, if a release layer or functional layer is provided on the first film, the thickness T l This value includes the release layer and the functional layer.

[0029] The first film of this disclosure has a storage modulus at 150°C obtained by dynamic viscoelasticity measurement in the tensile mode at a frequency of 10 Hz, which is E'. 150[×10 8 Pa], the thickness of the first film is T l When the size is [μm], the following equation (1) is satisfied. 40 ≤ (E' 150 ) 1 / 2 × T l ≤ 230 (1)

[0030] The value represented by formula (1) above is 40 or greater. This allows energy to dissipate during the filling process, suppressing excessive deformation and flow of the first film and resin composition layer, and ensuring sufficient thickness even at the edges of the sealing sheet. This improves seamlessness. The value represented by formula (1) above is preferably 45 or greater, more preferably 60 or greater, even more preferably 80 or greater, and particularly preferably 100 or greater. The value represented by formula (1) above is 230 or less. This controls the pressure transmission applied to the resin composition layer and the temperature transmission from the press machine upper plate during the filling process, allowing the resin composition layer to flow uniformly, resulting in good embedding performance, smoothness of the interface between the first film and the resin composition layer, and adhesion to the adherend. Furthermore, the value represented by formula (1) above is preferably 200 or less, more preferably 150 or less, and even more preferably 140 or less.

[0031] The value expressed in equation (1) above can be adjusted depending on the type and thickness of the first film. To increase the value of equation (1), for example, using a biaxially stretched first film or increasing the thickness of the first film is effective. To decrease the value of equation (1), for example, using an unstretched first film or decreasing the thickness of the first film is effective.

[0032] [Second film] The second film is not particularly limited, but examples include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin films such as polypropylene and polyethylene; and plastic films such as polyvinyl chloride films, polyurethane films, nylon films, polyolefin films, triacetylcellulose films, and cycloolefin films. From a handling standpoint, polyester films and polyolefin films are preferred. The second film is preferably directly laminated with the resin composition layer.

[0033] The second film preferably has a release layer on the surface facing the resin composition layer. The release layer is preferably formed by applying a release agent such as silicone resin, alkyd resin, fluororesin, or melamine resin to the film, and a release layer using silicone resin is more preferable from the viewpoint of handling (prevention of separation). The peeling force P2 of the second film is preferably 1 to 90 mN / 25 mm, more preferably 3 to 70 mN / 25 mm, and even more preferably 5 to 60 mN / 25 mm. The release force P2 of the second film can be adjusted by the release treatment of the release layer. For example, it can be adjusted by the type of release agent, the amount of release agent applied, and the surface roughness of the release layer. To decrease the release force, it is effective to increase the surface roughness or increase the amount of release agent applied, and to increase the release force, the opposite adjustments should be made. The peeling force P2 of the second film is preferably smaller than the peeling force P1 of the first film. Specifically, the value of P1 / P2 is more preferably between 1.1 and 20, and even more preferably between 1.1 and 17. The peeling force P2 of the second film can be measured, for example, by attaching the first film side of the sealing sheet to a SUS plate and peeling the second film from the resin composition layer at a peeling angle of 180° and a peeling speed of 300 mm / min in an environment of 23°C and 50% relative humidity. The second film may have a functional layer in addition to the release layer. Specific examples of functional layers include an antistatic layer, an anti-blocking layer, and a texture-forming layer. The thickness T2 of the second film is not particularly limited, but from a handling standpoint, it is preferably 12 to 188 μm, more preferably 12 to 100 μm, and even more preferably 20 to 60 μm. If a release layer or functional layer is provided on the second film, the thickness T2 is the value including the release layer and functional layer.

[0034] [Resin composition layer] The resin composition layer contains at least a resin component, i.e., resin (A), and may also contain at least one of a polymerization initiator (B), an inorganic filler (P), a colorant (Q), and a crosslinking agent (E), and may also contain other components. The resin composition layer is required to have various optical properties depending on the application. For example, in applications where high transparency is required, high transparency can be achieved by not using a colorant. In applications where light shielding is required, light shielding can be provided by using a black colorant. In applications where reflectivity is required, reflectivity can be provided by using a white colorant. In applications where a high refractive index is required, the refractive index can be changed to a high refractive index by using an inorganic filler (P) with a high refractive index. In this disclosure, resin (A) is a substance that has the function of bonding and fixing objects together as a binder. Specific examples include the function of bonding and fixing to a substrate having micro-LEDs or to micro-LEDs themselves.

[0035] In this specification, when the resin composition layer takes the form of a sealing sheet formed directly on the first film, the MD direction and TD direction of the sealing sheet are considered to coincide with the MD direction and TD direction of the first film, respectively.

[0036] The resin composition layer of this disclosure preferably has a glass transition temperature (Tg) of 20°C or higher, as determined by dynamic viscoelasticity measurement in the torsional mode at a frequency of 1 Hz, and a loss tangent (tanδ) at 100°C. 100It is preferable that ) is 0.2 or higher. A Tg of 20°C or higher further improves blocking suppression and prevention in process (a) shown in Figure 2. Also, tanδ 100 When tanδ is 0.2 or higher, in step (b) shown in Figure 2, the resin composition layer 11 becomes more easily deformable and flowable, further improving the ability to suppress and prevent air entrapment. 100 It is preferably 0.3 to 2.5, more preferably 0.3 to 2.0, and even more preferably 0.3 to 1.8. tanδ 100 However, a value of 0.2 or higher improves the diffusion of pressure applied to the resin composition layer 11 during the filling process, resulting in improved not only air entrapment suppression and prevention, but also embedding properties, smoothness, and adhesion to the substrate, which will be described later. tanδ 100 By keeping the value below 2.5, excessive deformation and flow of the resin composition layer during the filling process can be easily suppressed, and a sufficient thickness of the resin composition layer can be easily ensured even around the micro-LED. The above-mentioned Tg and tanδ 100 This is determined by dynamic viscoelasticity measurements in the torsional mode at a frequency of 1 Hz and a temperature range of -50 to 150°C. tanδ is the ratio of loss modulus to storage modulus, and Tg is the temperature at which tanδ peaks. 100 This is the ratio of the loss modulus to the storage modulus at 100°C.

[0037] Furthermore, the resin composition layer of this disclosure has a loss modulus (G'') at 100°C, obtained by dynamic viscoelastic measurement in the torsional mode at a frequency of 1 Hz. 100 ) but 5×10 3Pa ~2×10 7 Preferably, 1 × 10 4 Pa~9×10 6 It is more preferable that it be Pa, 2 × 10 4 Pa~5×10 5 It is even more preferable that it be Pa. G'' 100However, it is considered that when the values ​​are within the above range, the deformation and flow of the resin composition layer during the filling process improve, resulting in improved embedding properties, smoothness, and adhesion to the substrate. 100 is 2 x 10 7 By being below Pa, the resin composition layer can be easily deformed and flowed without energy dissipation during the filling process, improving its ability to fill recesses. 100 5 x 10 3 By having a Pa or higher pressure, energy is dissipated during the filling process, suppressing excessive deformation and flow of the resin composition layer, and ensuring sufficient thickness of the resin composition layer even around the micro-LED. Tg and tanδ 100 Ya G'' 100 This can be adjusted by the type and composition of the resin (A), the type and content of the polymerization initiator (B), the type, dispersion state and content of the inorganic filler (P) and colorant (Q), and also by the type and content of other components such as the crosslinking agent (E) and monomers.

[0038] Furthermore, it is preferable to measure the dynamic viscoelasticity of a resin composition layer laminated to a thickness of 500 μm or more, as described in the examples below. Two sets of sealing sheets are prepared, and the resin composition layers are bonded together in a laminator at 90°C to create a laminate of first film / resin composition layer / first film. Then, the first film on one side of the aforementioned laminate is peeled off, and the resin composition layer of the sealing sheet is repeatedly bonded to it until a thickness of 500 μm or more is achieved, after which the dynamic viscoelasticity can be measured. Alternatively, two sets of sealing sheets without a first film can be prepared, and a resin composition layer of 500 μm or more in thickness can be formed in the same manner.

[0039] Thickness T of the resin composition layer a From the viewpoint of embedding ability, a thickness of 1 to 100 μm is preferred, 2 to 60 μm is more preferred, 5 to 50 μm is even more preferred, and 10 to 40 μm is particularly preferred. Thickness T of the resin composition layer aBy setting the range to the above, the pressure applied to the resin composition layer during the filling process is appropriately distributed and sufficiently uniform, thereby further improving the embedding performance. The resin composition layer may be a single layer or a laminate of two or more layers; in the case of two or more layers, the total thickness is referred to. Thickness T of the resin composition layer a This can be adjusted by the resin composition layer formation method described later. Thickness T in this disclosure a This is measured by the method described in the examples below.

[0040] Thickness T of the resin composition layer a The formula 0.1≦T represents the ratio to the thickness T1 of the first film, which will be described later. a It is preferable that / T1 ≤ 3, and 0.2 ≤ T a It is more preferable that / T1 ≤ 1.5, and 0.2 ≤ T a It is even more preferable that / T1 ≤ 1.2 is satisfied. By setting the range as described above, the pressure transmission applied to the resin composition layer during the filling process described later is controlled, and the resin composition layer flows uniformly, resulting in better embedding performance.

[0041] A resin composition for forming a resin composition layer can be obtained, for example, by mixing a resin (A), at least one of a polymerization initiator (B), an inorganic filler (P), a colorant (Q), and a crosslinking agent (E), with a solvent (a dispersion medium for the filler (P) and colorant (Q), abbreviated as solvent). Any solvent can be used to adjust coating properties such as viscosity when mixing the components that make up the resin composition layer. For example, solvents that are compatible with resin (A), such as ester-based, ether-ester-based, ether-based, alcohol-based, and aromatic-based solvents, can be used as appropriate. Specifically, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, cyclohexanone, toluene, xylene, isopropyl alcohol, and N-methyl-2-pyrrolidone are examples of suitable solvents. For stirring, known stirring devices can be used, with dispersers, mixers, shakers, homogenizers, etc., being preferred. A resin composition that does not contain inorganic fillers (P) and colorants (Q) may be manufactured using a two-step process, first by mixing resin (A) and any solvent to create a mixture, and second by adding the remaining resin (A), polymerization initiator (B), and other components as needed. A resin composition containing either an inorganic filler (P) or a colorant (Q) may be manufactured using a two-step process, firstly by dispersing the inorganic filler (P) or colorant (Q) in any solvent to obtain a dispersion, and secondly by adding a resin (A), a polymerization initiator (B), and other components as needed. The resin (A) or dispersant may also be used when obtaining the dispersion.

[0042] [Resin (A)] The resin (A) is preferably a resin with a weight-average molecular weight (Mw) of 10,000 or more. Including a resin (A) with an Mw of 10,000 or more can further improve the film-forming properties of the resin composition layer. Furthermore, by using a portion of the resin (A) as a dispersant for the inorganic filler (P) or colorant (Q), the uniform dispersion of the inorganic filler (P) or colorant (Q) within the resin composition layer can be further improved. The upper limit of the Mw of resin (A) is preferably 1,000,000, more preferably 500,000, even more preferably 300,000, and even more preferably 200,000. The lower limit of the Mw of resin (A) is more preferably 10,000, even more preferably 20,000, and particularly preferably 30,000. Note that the weight-average molecular weight (Mw) is a polystyrene-converted value measured by gel permeation chromatography (GPC). The weight-average molecular weight (Mw) in this disclosure is measured by the method described in the examples below.

[0043] Resin (A) can be used alone or in combination of two or more types. The content of resin (A) is preferably 10 to 99% by mass, more preferably 25 to 95% by mass, and even more preferably 60 to 90% by mass, based on the total amount (100% by mass) of the resin composition layer. When two or more types of resin (A) are included, it is preferable that each resin (A) has a content of 5% by mass or more, and that the total content is within the above range. By setting the resin (A) content within the above range, compatibility with either the inorganic filler (P) or the colorant (Q) is improved when either is included, resulting in improved optical properties.

[0044] Preferred examples of resin (A) include (meth)acrylic resin (a1), urethane resins such as polyurethane resin and polyurethane urea resin (a2), epoxy resin (a3), maleic acid resin, styrene-maleic acid copolymer, polystyrene resin, polybutadiene resin, polyester resin, condensation-type polyester resin, addition-type polyester resin, melamine resin, polycarbonate resin, oxetane resin, phenoxy resin, polyimide resin, polyamide-imide resin, alkyd resin, amino resin, polyamide resin, polylactic acid resin, oxazoline resin, benzoxazine resin, silicone resin, fluororesin, butyral resin, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, vinyl resin, rubber resin, cyclic rubber resin, cellulose, polyethylene (HDPE, LDPE), etc. From the viewpoint of embedding properties, it is preferable to include at least one of (meth)acrylic resin (a1), urethane resin (a2), and epoxy resin (a3). Furthermore, from the viewpoint of adhesion, it is more preferable to include (meth)acrylic resin (a1). From the viewpoint of storage stability, it is particularly preferable that the resin composition layer contains 50% or more (meth)acrylic resin when the solid content is 100% by mass.

[0045] Resin (A) preferably has one or more functional groups that can be used in polymerization / crosslinking reactions induced by heat or light. The functional groups can be appropriately selected based on their reactivity with other resins (A) or with the polymerization initiator (B) and crosslinking agent (E) described later, and may be self-crosslinkable functional groups. Examples of functional groups include hydroxyl groups, carboxyl groups, amino groups, epoxy groups, oxetanyl groups, oxazoline groups, oxazine groups, aziridine groups, thiol groups, isocyanate groups, blocked isocyanate groups, silanol groups, (meth)acryloyl groups, N-vinyl groups, vinyl ether groups, allyl groups, and unsaturated carboxylic acid groups. Radical polymerizable functional groups such as (meth)acryloyl groups, N-vinyl groups, vinyl ether groups, allyl groups, and unsaturated carboxylic acid groups are preferred.

[0046] [(Meth)acrylic resin (a1)] In this disclosure, (meth)acrylic resin (a1) is a (meth)acrylic copolymer obtained by copolymerizing (meth)acrylic acid ester monomers, and is a polymer having 2 to 20,000 monomer-based structural units. A preferred example of the (meth)acrylic acid ester monomer is alkyl (meth)acrylic acid ester monomer. When introducing functional groups that can be used in polymerization / crosslinking reactions, a (meth)acrylic copolymer obtained by copolymerizing a functional group-containing monomer with a (meth)acrylic acid ester monomer is preferred. The (meth)acrylic resin (a1) of this disclosure excludes compounds containing two or more urethane bonds in the main chain and compounds having two or more epoxy groups in one molecule. The main chain as used herein refers to the region where the carbon-carbon double bond site of the (meth)acrylic acid ester monomer is cleaved and polymerization reactions are repeated, resulting in a continuous chain of extended bond sites.

[0047] Alkyl (meth)acrylate monomers are compounds obtained by esterifying (meth)acrylic acid and introducing an alkyl or cycloalkyl group, where the alkyl or cycloalkyl group may be a linear, branched, or cyclic saturated aliphatic hydrocarbon group. A saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms is preferred, and a saturated aliphatic hydrocarbon group having 1 to 12 carbon atoms is more preferred. Specific examples include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, and (meth)acrylic acid. Examples include decyl, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, 4-n-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, etc. Among these, methyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate are particularly preferred from the viewpoint of dispersibility of inorganic fillers (P) and colorants (Q), with methyl (meth)acrylate and n-butyl (meth)acrylate being the most preferred.

[0048] The (meth)acrylic resin (a1) preferably contains 1 to 100% by mass of structural units derived from alkyl (meth)acrylate monomers, more preferably 20 to 99.5% by mass, and even more preferably 80 to 99% by mass, of the monomers constituting the (meth)acrylic resin (a1) from the viewpoint of adhesion.

[0049] The (meth)acrylic resin (a1) preferably has structural units derived from functional group-containing monomers and / or unsaturated bonds. Examples of functional group-containing monomers include carboxyl group-containing monomers, hydroxyl group-containing monomers, epoxy group-containing monomers, and amino group-containing monomers. The inclusion of functional group-containing monomers improves the cohesive strength of resin (A), resulting in a tough resin composition layer. In particular, the inclusion of carboxyl group-containing monomers, hydroxyl group-containing monomers, and epoxy group-containing monomers is preferred.

[0050] Examples of carboxyl group-containing monomers include (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, (meth)acrylic acid is preferred from the viewpoint of adhesion.

[0051] Examples of hydroxyl group-containing monomers include 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, 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate are more preferred from the viewpoint of adhesion.

[0052] Examples of epoxy group-containing monomers include glycidyl (meth)acrylate and glycidyl 4-hydroxybutyl acrylate ether.

[0053] Examples of amino group-containing monomers include monoalkylamino esters of (meth)acrylates such as monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, and monoethylaminopropyl (meth)acrylate.

[0054] The (meth)acrylic resin (a1) preferably contains a total of 0.1 to 20% by mass of structural units derived from functional group-containing monomers in 100% by mass of the monomers constituting the (meth)acrylic resin (a1). By setting the (meth)acrylic resin (a1) within this range, the adhesion strength can be adjusted. It is preferable that the material contains 0.1 to 10% by mass of constituent units derived from carboxyl group-containing monomers. Being within this range further enhances adhesion. It is preferable that the constituent units derived from hydroxyl group-containing monomers be present in an amount of 0.1 to 10% by mass. Being within this range can further enhance adhesion.

[0055] For the purpose of introducing unsaturated bonds into (meth)acrylic resin (a1), monomers having epoxy groups or monomers having isocyanate groups can be used. An (meth)acrylic resin (a1) having unsaturated bonds can be obtained by the following two-step reaction. First, a monomer having a carboxyl group, such as (meth)acrylic acid, is used to obtain a (meth)acrylic copolymer having a carboxyl group, or a monomer having a hydroxyl group, such as 2-hydroxyethyl (meth)acrylic acid, is used to obtain a (meth)acrylic copolymer having a hydroxyl group. Next, it is preferable to react at least a portion (10 to 100 mol%) of the carboxyl groups or hydroxyl groups of the (meth)acrylic copolymer with the epoxy groups or isocyanate groups in a monomer having an unsaturated bond, such as an epoxy group or isocyanate group and an (meth)acryloyl group, to introduce an unsaturated bond, such as a (meth)acryloyl group, into the (meth)acrylic resin (a1). Note that the monomer having an epoxy group or isocyanate group and an unsaturated bond, such as a (meth)acryloyl group, is sometimes called a modifying agent, in the sense that it modifies the (meth)acrylic copolymer. The amount of unsaturated bonds, such as (meth)acryloyl groups, introduced is not limited. (meth)acrylic resin (a1) may also have carboxyl groups and hydroxyl groups in addition to unsaturated bonds such as (meth)acryloyl groups.

[0056] Examples of monomers having an epoxy group and an unsaturated bond such as a (meth)acryloyl group include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 6-methyl-3,4-epoxycyclohexylmethyl (meth)acrylate. Among these, glycidyl (meth)acrylate is preferred from the viewpoint of reactivity. It is preferable that there be one or fewer epoxy groups per molecule in the monomer having an epoxy group and an unsaturated bond such as a (meth)acryloyl group. Examples of monomers having an isocyanate group and an unsaturated bond such as a (meth)acryloyl group include Karenz MOI and AOI (trade names, Resonac Co., Ltd.).

[0057] The (meth)acrylic resin (a1) may contain structural units derived from alkyl (meth)acrylates and other monomers copolymerizable with functional group-containing monomers. Examples include monomers having alkylene oxy groups and other vinyl monomers. Examples include methoxyethyl acrylate, methoxydiethylene glycol acrylate, vinyl acetate, vinyl crotate, styrene, acrylonitrile, and acrylamide. The structural units derived from the other monomers are preferably present in an amount of 0.1 to 20% by mass of 100% by mass of the monomers constituting the (meth)acrylic resin (a1).

[0058] (Meth)acrylic resin (a1) is obtained by polymerizing the above-mentioned (meth)acrylic monomer mixture. A polymerization initiator may be used during polymerization as needed. The amount of polymerization initiator is, for example, 0.01 to 10 parts by mass per 100 parts by mass of the monomer mixture. The polymerization method is not limited. For example, polymerization can be carried out by solution polymerization, bulk polymerization, emulsion polymerization, or suspension polymerization, and solution polymerization is the most preferred due to the ease of polymerization control. Examples of solvents used in solution polymerization include 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.

[0059] A radical polymerization initiator is preferred as the polymerization initiator. Peroxides and azo compounds are preferred as radical polymerization initiators. Any of the thermal radical polymerization initiators described later can be used, and specifically, 2,2'-azobisisobutyronitrile (abbreviated as AIBN) is preferred.

[0060] [Urethane resin (a2)] In this disclosure, urethane resin (a2) is a compound that can be obtained by reacting a polyisocyanate with a polyol and contains two or more urethane bonds in its main chain. The main chain, as used here, refers to a region where the bond sites extended by the reaction of the polyisocyanate and the polyol are continuous. The polyisocyanate can be any polyisocyanate having two or more isocyanate groups in one molecule. From the viewpoint of dispersibility of inorganic fillers (P) and colorants (Q), diisocyanates or triisocyanates are preferred, and diisocyanates are more preferred. As the diisocyanate, it can be appropriately selected from known aliphatic diisocyanates such as hexamethylene diisocyanate or known aromatic diisocyanates such as benzene-1,3-diisocyanate. Alternatively, an isocyanate-terminated prepolymer obtained by reacting a polyol with an excess of polyisocyanate may be used as an intermediate for the urethane resin. The polyol can be any polyol having two or more hydroxyl groups in one molecule. From the viewpoint of dispersibility of inorganic fillers (P) and colorants (Q), diols or triols are preferred, and diols are more preferred. As the diol, known aliphatic diols such as ethylene glycol and known aromatic diols such as benzenediol can be appropriately selected and used. Prepolymers such as polyether polyols, polyester polyols, and polycarbonate polyols may also be used.

[0061] The urethane resin (a2) may further be a polyurethane urea resin having urea bonds. Polyurethane urea resin can be synthesized, for example, by reacting a polyamine with a urethane resin having isocyanate groups at its terminals. The polyamine can be any polyamine having two or more amino groups in one molecule. From the viewpoint of dispersibility of inorganic fillers (P) and colorants (Q), diamines or triamines are preferred, and diamines are more preferred. As the diamine, known aliphatic diamines such as ethylenediamine and known aromatic diamines such as phenylenediamine can be appropriately selected and used.

[0062] From the viewpoint of dispersibility of inorganic fillers (P) and colorants (Q), the urethane resin (a2) preferably has radical polymerizable functional groups such as (meth)acryloyl groups, N-vinyl groups, vinyl ether groups, allyl groups, and unsaturated carboxylic acid groups as functional groups, and it is even more preferable that it has (meth)acryloyl groups. Specifically, (meth)acryloyl groups can be introduced by addition reaction between the aforementioned polyol, diisocyanate, or triisocyanate and an acrylate having a hydroxyl group.

[0063] [Epoxy resin (a3)] In this disclosure, epoxy resin (a3) ​​is a resin having two or more epoxy groups in one molecule and a weight-average molecular weight (Mw) of 10,000 or more. Epoxy resin (a3) ​​also includes compounds with added functional groups. Preferably, the functional group is a radical polymerizable functional group such as a (meth)acryloyl group, N-vinyl group, vinyl ether group, allyl group, or unsaturated carboxylic acid group, and more preferably a (meth)acryloyl group. Regarding the properties of epoxy resin (a3), using it in liquid form can improve adhesion, while using it in solid form can improve film formation of the resin composition layer. As for the epoxy resin (a3), for example, glycicyl ether type epoxy resin, glycicylamine type epoxy resin, glycidyl ester type epoxy resin, cyclic aliphatic (alicyclic) epoxy resin, bisphenol type epoxy resin, hydrogenated bisphenol type epoxy resin, etc. are preferred. Furthermore, from the viewpoint of adhesion, the epoxy resin (a3) ​​is more preferably a bisphenol type epoxy resin or a high-purity hydrogenated epoxy resin. As a compound in which a radically polymerizable functional group is added as a functional group to one or more epoxy groups, bisphenol A type diglycidyl ether diacrylate is preferred.

[0064] Examples of glycidyl ether type epoxy resins include cresol novolac type epoxy resins, tris(glycidyloxyphenyl)methane, and tetrakis(glycidyloxyphenyl)ethane. Examples of glycidylamine-type epoxy resins include tetraglycidyldiaminodiphenylmethane and tetraglycidylmetaxylylenediamine. Examples of glycidyl ester type epoxy resins include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate. Examples of cyclic aliphatic (alicyclic) epoxy resins include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate. Examples of bisphenol-type epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy crosslinking agent, bisphenol S type epoxy resin, and bisphenol AD ​​type epoxy resin. Bisphenol A type epoxy resin is particularly preferred from the viewpoint of adhesion. Examples of hydrogenated bisphenol-type epoxy resins include hydrogenated bisphenol A epoxy resin and hydrogenated bisphenol F epoxy resin. Hydrogenated bisphenol A epoxy resin is particularly preferred from the viewpoint of adhesion.

[0065] [Polymerization initiator (B)] In this embodiment, either a thermal polymerization initiator or a photopolymerization initiator can be used, but it is preferable to use a thermal polymerization initiator from the viewpoint of film-forming properties and adhesion of the resin composition layer. When using either a thermal polymerization initiator or a photopolymerization initiator, it is preferable that the resin (A) has one or more radical polymerizable functional groups per molecule. Examples of radical polymerizable functional groups include (meth)acryloyl groups, N-vinyl groups, vinyl ether groups, allyl groups, etc., with (meth)acryloyl groups being preferred.

[0066] In this embodiment, a thermal radical polymerization initiator and a thermal cationic polymerization initiator can be used as thermal polymerization initiators. From the viewpoint of storage stability of the resin composition layer, a thermal radical polymerization initiator is preferred. Thermal radical polymerization initiators have the function of generating radicals when heated. Examples of thermal radical polymerization initiators include organic peroxide polymerization initiators and azo thermal polymerization initiators.

[0067] From the viewpoint of storage stability, azo thermal polymerization initiators are preferably used. From the viewpoint of suppressing foaming during curing and improving the appearance after curing, organic peroxide polymerization initiators are preferably used. Thermal radical polymerization initiators adjust the shrinkage force during thermal curing, resulting in desirable sealing properties and low-temperature curing properties. In particular, when using thermal radical polymerization initiators, from the viewpoint of storage stability and reaction stability, it is preferable that the 10-hour half-life temperature is between 60°C and 170°C.

[0068] Examples of organic peroxide polymerization initiators with a 10-hour half-life temperature of 60°C to 170°C include dialkyl peroxides such as di-t-amyl peroxide (123°C), di-t-butyl peroxide (129°C), di-t-hexyl peroxide (116°C), dicumyl peroxide (116°C), t-butylcumyl peroxide (120°C), α,α'-bis(t-butylperoxy-m-isopropyl)benzene (119°C), 2,5-dimethyl-2,5-bis(t-butylperoxy)hexine-3 (131°C), and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane (120°C); t-Amyl peroxyacetate (100°C), t-Butyl peroxyacetate (102°C), t-Amyl peroxybenzoate (100°C), t-Butyl peroxybenzoate (104°C), t-Hexyl peroxybenzoate (99°C), t-Amyl peroxy-2-ethylhexanoate (75°C), t-Butyl peroxy-2-ethylhexanoate (72°C), t-Hexyl peroxy-2-ethylhexanoate (70°C), 1,1,3,3-Tetramethylbutyl peroxy-2-ethylhexanoate (65°C), t-Butyl Peroxyesters such as peroxy-3,5,5-trimethylhexanoate (97°C), t-butyl peroxyisobutyrate (75°C), t-amyl peroxyisononanoate (96°C), t-butyl peroxyisononanoate (102°C), t-butyl peroxylaurate (98°C), n-butyl 4,4-di-(t-butylperoxy)valerate (105°C), 2,5-dimethyl-2,5-di(benzoylperoxy)hexane (100°C), and 2,5-dimethyl-2,5-di-2-ethylhexanoylperoxyhexane (66°C); Peroxyketals such as 2,2-bis(t-butylperoxy)butane (103°C), 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane (95°C), 1,1-bis(t-amylperoxy)cyclohexane (93°C), 1,1-bis(t-butylperoxy)cyclohexane (97°C), 1,1-bis(t-hexylperoxy)cyclohexane (87°C), and 4,4-bis(t-butylperoxy)butyl pentanoate; Hydroperoxides such as t-amyl hydroperoxide (165°C), cumene hydroperoxide (158°C), p-menthane hydroperoxide (128°C), diisopropylbenzene hydroperoxide (145°C), and 1,1,3,3-tetramethylbutyl hydroperoxide (153°C); Diacyl peroxides such as dibenzoyl peroxide (73°C), diisononanoyl peroxide (61°C), dilauroyl peroxide (64°C), and disuccinate peroxide (66°C); Examples of peroxy carbonates include, but are not limited to, t-butyl peroxyisopropyl carbonate (99°C), t-amyl peroxyisopropyl carbonate (96°C), t-hexyl peroxyisopropyl carbonate (95°C), t-butyl peroxy-2-ethylhexyl carbonate (99°C), and t-amyl peroxy-2-ethylhexyl carbonate (99°C). From the viewpoint of storage stability, dialkyl peroxides are preferred, and di-t-butyl peroxide and n-butyl 4,4-di(t-butylperoxy)valerate are more preferred.

[0069] Examples of azo thermal polymerization initiators with a 10-hour half-life temperature of 60°C to 170°C include 2,2'-azobisisobutyronitrile (65°C), 2,2'-azobis(2-methylbutyronitrile) (68°C), and other 2,2'-azobisbutyronitriles; 1,1'-azobis-1-alkanenitriles such as 1,1'-azobis(cyclohexane-1-carbonitride) (88°C); 2,2'-azobispropionamides such as 2,2'-azobis(N-butyl-2-methylpropionamide) (110°C); Other examples include dimethyl-1,1'-azobis(1-cyclohexanecarboxylate) (73°C), dimethyl-2,2'-azobis(2-methylpropionate) (66°C), 2,2'-azobis(2,4,4-trimethylpentane) (110°C), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] (61°C), 2,2'-azobiisobutyrate, and 1,1'-azobis(acetoxy-1-phenylethane). Azo compounds having carboxyl groups or hydroxyl groups include, but are not limited to, 4,4'-azibis(4-cyanopentanoic acid) and 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide). From the viewpoint of storage stability, 2,2'-azobispropionamides are preferred, and 2,2'-azobis(N-butyl-2-methylpropionamide) is more preferred.

[0070] The thermal radical polymerization initiator is preferably contained in an amount of 0.01 to 20% by mass, more preferably 0.1 to 18% by mass, even more preferably 0.8 to 16% by mass, even more preferably 1 to 13% by mass, and particularly preferably 4.4 to 13% by mass, based on 100% by mass of the total solids content of the resin composition layer. A concentration of 0.01 to 20% by mass provides excellent transparency of the cured resin composition layer in transparent applications. Furthermore, a concentration of 0.01% by mass or more provides excellent low-temperature curing properties and handling, while a concentration of 20% by mass or less provides excellent storage stability. For the same reasons as described above, the amount of peroxide-based thermal radical polymerization initiator blended is preferably 0.01 to 20% by mass, more preferably 0.1 to 18% by mass, even more preferably 0.8 to 16% by mass, even more preferably 1 to 13% by mass, and particularly preferably 4.4 to 13% by mass.

[0071] Furthermore, from the viewpoint of storage stability, it is preferable not to use thermal radical polymerization initiators in combination with photoradical polymerization initiators.

[0072] Examples of photopolymerization initiators 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 preferred because they cause less yellowing during the heating and aging process. From the viewpoint of preventing yellowing, the content of the photopolymerization initiator is preferably 0.5 to 10% by mass, and more preferably 0.5 to 5% by mass, based on the total amount (100% by mass) of the resin composition layer.

[0073] [Coloring agent (Q)] For the purpose of forming a reflective layer, a coloring agent (Q) such as titanium dioxide, zinc oxide, or lithopone can be used. From the viewpoint of whiteness, a white pigment is preferred, and among these, titanium dioxide is preferred from the viewpoint of dispersibility. By using a white pigment to make the resin composition layer white and sealing the spaces between multiple micro-LEDs or around multiple micro-LEDs, the resin composition layer functions as a reflective layer, and the brightness of the micro-LEDs can be further increased.

[0074] Known titanium dioxide such as rutile-type titanium dioxide and anatase-type titanium dioxide can be used as the titanium dioxide used in this disclosure. From the viewpoint of resin degradation due to light, rutile-type titanium dioxide is preferred. Specific examples of rutile-type titanium dioxide include "Typeque R-820, R-830, R-930, R-550, R-630, R-680, R-670, R-680, R-670, R-780, R-850, CR-50, CR-57, CR-80, CR-90, 90-2, CR-93, CR-95, CR-97, CR-63, CR-58, UT771" from Ishihara Sangyo Co., Ltd., "Typeque R-101, R-103, R-104, R-105, R-108, R-900, R-902+, R-960, R-706" from DuPont, and "TITONE" from Sakai Chemical Industry Co., Ltd. Examples include "R-25, R-21, R-32, R-7E, R-5N, R-62N, R-42, R-45M, GTR-100, D-918," etc.

[0075] The arithmetic mean particle size of rutile-type titanium dioxide is preferably 0.1 to 1.5 μm, and more preferably 0.15 to 1.1 μm. Setting the arithmetic mean particle size to 0.1 μm or more makes it easier to prevent aggregation and sedimentation of titanium dioxide in the coating solution for the resin composition layer. Furthermore, setting the arithmetic mean particle size to 1.5 μm or less improves whiteness and exhibits high reflectivity. When the particle shape of the colorant (Q) has an average aspect ratio (long axis length / short axis length) of 1.5 or more, the arithmetic mean particle size is determined by averaging the long axis lengths. The arithmetic mean particle size of the colorant (P) can be determined from the average value of about 20 primary particles that can be observed from an image magnified to about 50,000 to 1,000,000 times using a transmission electron microscope (TEM).

[0076] The amount of white pigment blended is preferably 0.1 to 35% by mass of the colorant (Q) in 100% by mass of the total solid content of the resin composition layer. The lower limit of the blending amount is more preferably 0.5% by mass, even more preferably 1% by mass, and even more preferably 5% by mass. The upper limit of the blending amount is more preferably 30% by mass, even more preferably 28% by mass, and particularly preferably 20% by mass. By having a content of 0.1 to 35% by mass, a resin composition layer with good reflectivity, sealing properties, and handling properties can be obtained.

[0077] When the purpose is to form a light-shielding layer, it is preferable to use a black coloring agent (pigment, dye, etc.) as the coloring agent (Q). Specifically, examples include carbon black, graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complex, anthraquinone-based coloring agents, zirconium nitride, etc. One type of black coloring agent may be used, or two or more types may be used. In addition, a coloring agent that functions as a black coloring agent may be used by combining coloring agents that exhibit colors other than black.

[0078] Among the colorants (Q), carbon black is particularly preferred in terms of its dispersibility in radically polymerizable organic compounds and its light-shielding properties. The carbon black used can be any carbon black commonly used as a black colorant. As the carbon black, one or more known types of carbon black, such as channel black, furnace black, thermal black, lamp black, or acetylene black, can be used. Resin-coated carbon black may also be used. Furthermore, carbon nanofibers or carbon nanotubes may be used. When incorporating carbon black into the resin composition layer, carbon black powder may be added, or a carbon black dispersion may be added. The average particle size of carbon black is preferably between 10 nm and 500 nm, more preferably between 10 nm and 300 nm, and even more preferably between 10 nm and 100 nm, from the viewpoint of light shielding properties. The average particle size is the arithmetic mean primary particle size determined by observation with an electron microscope. From the viewpoint of dispersibility, carbon black with a specific surface area of ​​50-400 m2 / g by the BET method, a volatile content of 0.1-10% by weight, and a pH of 2-10 is preferred, with a pH of 3-8 being more preferred, and a pH of 3-6 being even more preferred.

[0079] From the viewpoint of exhibiting the properties of the colorant (Q), the amount of colorant (Q) blended is preferably 0.1% by mass or more out of 100% by mass of the total solid content of the resin composition layer. The lower limit of the amount of colorant (Q) blended is more preferably 0.5% by mass, even more preferably 1% by mass, and particularly preferably 5% by mass. The upper limit of the amount of colorant (Q) blended is, for example, 80% by mass, 40% by mass, etc. From the viewpoint of obtaining a resin composition layer with good light-shielding properties, sealing properties, and handling properties, the upper limit is preferably 35% by mass, more preferably 32% by mass, even more preferably 30% by mass, even more preferably 28% by mass, and particularly preferably 20% by mass.

[0080] [Inorganic filler (P)] The resin composition layer may contain inorganic fillers (P) other than those described above (hereinafter simply referred to as inorganic fillers (P)). Examples of such inorganic fillers (P) include silica such as amorphous silica, crystalline silica, fused silica, and spherical silica, alumina, titanium oxide, antimony trioxide, magnesium oxide, tin oxide, zirconium oxide, magnesium hydroxide, barium sulfate, barium titanate, calcium carbonate, talc, clay, Neuburg silica particles, boehmite, magnesium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, calcium zirconate, kaolinite, mica, sericite, montmorrolinite, bentonite, magnesium carbonate base, boron nitride, aluminum nitride, and titanium nitride. Examples of inorganic fillers (P) include metal powders such as copper, tin, zinc, nickel, silver, palladium, aluminum, iron, cobalt, gold, and platinum. It is preferable that the inorganic fillers (P) are spherical particles. Among these, silica is preferred, as it suppresses curing shrinkage of the cured resin composition layer and improves properties such as adhesion and hardness. When imparting high refractive index to the resin composition layer, it is preferable that the total light transmittance in the visible light band (380-780 nm) of the resin composition layer be 70% or more, and the refractive index be 1.47-1.56. A total light transmittance of 80% or more is more preferable, 85% or more is even more preferable, 90% or more is even more preferable, and 92% or more is particularly preferable. The lower limit of the refractive index is more preferable to 1.49, and 1.51 is even more preferable. The upper limit of the refractive index is more preferable to 1.54, and 1.53 is even more preferable. From the viewpoint of adjusting the refractive index, inorganic fillers (P) such as alumina, titanium oxide, and zirconium oxide may be added. Total light transmittance is the ratio of the total amount of transmitted light that passes through the cured layer to the total amount of incident light that enters the cured layer obtained by heat-treating the resin composition layer at 130°C for 120 minutes.

[0081] Inorganic fillers (P) have a specific surface area of ​​5-400 m² as measured by the BET method, from the perspective of dispersibility. 2 It is preferable that the value be / g, and 10-150m 2 It is more preferable that the amount be / g, and 20-90m 2 It is even more preferable that it be / g. The average primary particle diameter (hereinafter referred to as particle diameter) of the inorganic filler (P) is preferably 1 to 1200 nm. A particle diameter of 1 nm or more makes it easier to maintain the viscosity of the resin composition at a level suitable for coating. Furthermore, a particle diameter of 1200 nm or less improves the coating film resistance. A particle diameter of 5 to 1000 nm is more preferable, 10 to 700 nm is even more preferable, and 50 to 300 nm is particularly preferable. The particle diameter of the inorganic filler (P) can be determined from the average value of about 20 primary particles observed from an image magnified to approximately 50,000 to 1,000,000 times using a transmission electron microscope (TEM). If the particle shape of the inorganic filler (P) has an average aspect ratio (long axis length / short axis length) of 1.5 or more, the particle diameter is determined by averaging the long axis lengths.

[0082] The content of inorganic filler (P) (total content if two or more types are included) is preferably 0.01 to 40% by mass, more preferably 0.1 to 30% by mass, and even more preferably 0.5 to 20% by mass, based on the total amount of solids in the resin composition layer, from the viewpoint of embedding properties. Including 0.01 to 40% by mass of inorganic filler (P) makes it easier to increase the fluidity of the resin composition layer during the filling process, thereby improving embedding properties.

[0083] From the viewpoint of dispersibility, it is preferable that the inorganic filler (P) is surface-modified with a surface modifier. Examples of surface modifiers include organic acids, silane coupling agents, surfactants, titanium coupling agents, and metal impurities, and it is preferable that the inorganic filler (P) contains an organic acid. Surface treatments that do not introduce organic groups, such as alumina treatment, may also be performed. The surface treatment method for the inorganic filler (P) is not particularly limited, and any known and conventional method may be used. The surface of the inorganic filler (P) may be treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group.

[0084] [Inorganic fillers (P) and colorants (Q)] From the viewpoint of adjusting the film-forming properties and reflectivity of the resin composition layer, it is preferable to disperse the colorant (Q) and inorganic filler (P) in the resin (A) and use them as a dispersion. As for the dispersion treatment, any commonly used disperser can be used for mechanical crushing, but examples include ball mills, roll mills, sand mills, bead mills and nanomizers. Among these, bead mills are preferably used. Examples of such bead mills include Super Mill, Sand Grinder, Agitator Mill, Glen Mill, Dyno Mill, Pearl Mill and Cobol Mill (all are trade names).

[0085] In this disclosure, from the viewpoint of storage stability of the dispersion, it is preferable to use a dispersant in the dispersion treatment of the colorant (Q) and inorganic filler (P). In this disclosure, the dispersant has the function of imparting repulsive force between particles so that the particles separated after the aforementioned dispersion treatment do not aggregate again. Conventional known compounds can be used as dispersants, including, for example, cationic, anionic, or nonionic surfactants, cationic, anionic, or nonionic polymeric dispersants, and pigment derivative-type dispersants. From the viewpoint of storage stability of the dispersion, pigment derivative-type dispersants are preferred.

[0086] Pigment derivative-type dispersants are compounds having acidic groups, basic groups, neutral groups, etc., in their organic pigment residues. Examples include compounds having acidic substituents such as sulfo groups, carboxyl groups, or phosphate groups, as well as their amine salts, compounds having basic substituents such as sulfonamide groups, amide groups, or tertiary amino groups at the terminal, and compounds having neutral substituents such as phenyl groups or phthalimidoalkyl groups. Examples of organic pigments include phthalocyanine pigments, diketopyrrolopyrrole pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, perinone pigments, perylene pigments, thiaidine indigo pigments, triazine pigments, benzimidazolone pigments, indole pigments such as benzoisoindole, isoindoline pigments, isoindolinone pigments, quinophthalone pigments, naphthol pigments, surene pigments, metal complex pigments, and azo pigments such as azo, disazo, and polyazo. By using these pigment dispersants, it is possible to prevent the aggregation of colorants (Q) and inorganic fillers (P) contained in the resin composition layer over time, thereby maintaining good coating stability.

[0087] When the resin composition layer contains a white coloring agent, the dispersant content (total content if two or more types are included) is preferably 0.01 to 35% by mass, and more preferably 0.1 to 20% by mass, based on the total amount (100% by mass) of the resin composition layer. Including 0.01% by mass or more of the dispersant results in good light reflectivity, and an amount of 35% by mass or less results in a suitable viscosity range for the white resin composition used to form the resin composition layer, leading to good coating suitability. When the resin composition layer contains a black coloring agent, the pigment dispersant content (total content if two or more types are included) is preferably 0.01 to 30% by mass, and more preferably 0.1 to 20% by mass, based on the total amount (100% by mass) of the resin composition layer. Including 0.01% by mass or more of the pigment dispersant results in good light shielding properties, and an amount of 30% by mass or less results in a suitable viscosity range for the black resin composition used to form the resin composition layer, leading to good coating suitability. When the resin composition layer contains an inorganic filler (P), the dispersant content is preferably 0.01 to 45% by mass, more preferably 0.1 to 35% by mass, and more preferably 1 to 30% by mass, based on the total amount of solids in the resin composition layer. Including 0.01% by mass or more of the dispersant results in good brightness of the optical semiconductor device, and an amount of 45% by mass or less results in a suitable viscosity range for the dispersion and good coating suitability.

[0088] [Crosslinking agent (E)] The resin composition layer of this disclosure may contain a crosslinking agent (E). The crosslinking agent (E) enhances the cohesive force of the resin composition layer and improves adhesion by crosslinking with the reactive functional groups of the resin (A) during the heat pressing and heat aging processes in the filling process. The crosslinking agent (E) has multiple functional groups that can react with the functional groups of the resin (A). Examples of known compounds for the crosslinking agent (E) include acid anhydride group-containing compounds, imidazole compounds, isocyanate compounds, aziridine compounds, amine compounds, and compounds having epoxy groups. The loss tangent (tanδ) of the resin composition layer 100 From the viewpoint of adjusting the ), isocyanate compounds, compounds having epoxy groups, aziridine compounds, and imidazole compounds are preferred.

[0089] An isocyanate compound is an isocyanate having two or more isocyanate groups. If resin (A) has hydroxyl groups or amino groups, it can react with isocyanate groups. The isocyanate compounds are preferably isocyanate monomers such as aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates, as well as their burette, nurate, and adduct forms. From the viewpoint of forming a sufficient crosslinked structure, trifunctional isocyanate compounds are preferred. More preferably, the isocyanate compounds are adducts and nurates, which are reaction products of an isocyanate monomer and a trifunctional low-molecular-weight active hydrogen-containing compound. Examples of adducts include the trimethylolpropane adduct of hexamethylene diisocyanate, the trimethylolpropane adduct of tolylene diisocyanate, and the trimethylolpropane adduct of isophorone diisocyanate. Examples of nurates include the nurate of hexamethylene diisocyanate, the nurate of tolylene diisocyanate, and the nurate of isophorone diisocyanate, with the trimethylolpropane adduct of hexamethylene diisocyanate, the trimethylolpropane adduct of tolylene diisocyanate, and the trimethylolpropane adduct of isophorone diisocyanate being more preferred.

[0090] When the resin (A) has a carboxyl group, a compound having an epoxy group and a weight-average molecular weight (Mw) of less than 10,000 can be suitably used as the crosslinking agent (E). Preferred epoxy group-containing compounds include glycicyl ether type epoxy compounds, glycicylamine type epoxy compounds, glycidyl ester type epoxy compounds, and cyclic aliphatic (alicyclic) epoxy compounds.

[0091] Examples of glycidyl ether type epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, bisphenol AD ​​type epoxy compounds, cresol novolac type epoxy compounds, phenol novolac type epoxy compounds, α-naphthol novolac type epoxy compounds, bisphenol A type novolac type epoxy compounds, dicyclopentadiene type epoxy compounds, tetrabrom bisphenol A type epoxy compounds, brominated phenol novolac type epoxy compounds, tris(glycidyloxyphenyl)methane, tetrakis(glycidyloxyphenyl)ethane, and the like.

[0092] Examples of glycidylamine-type epoxy compounds include tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, triglycidylmethaminophenol, and tetraglycidylmetaxylylenediamine.

[0093] Examples of glycidyl ester type epoxy compounds include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate.

[0094] Examples of cyclic aliphatic (alicyclic) epoxy compounds include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate.

[0095] Examples of aziridine compounds include trimethylolpropane tris[3-(aziridin-1-yl)propionate], tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridincarboxyamide), N,N'-hexamethylene-1,6-bis(1-aziridincarboxyamide), tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, and 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane.

[0096] Imidazole compounds include 2-methylimidazole, 2-phenyl-4-methylimidazole, 2,4-dimethylimidazole, 2-phenylimidazole, imidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[ Examples of imidazole compounds include 2'-methylimidazolyl-(1')-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2-phenylimidazole isocyanurate adduct, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Furthermore, compounds with improved storage stability, such as those in which imidazole compounds are encapsulated in microcapsules, are also included.

[0097] The content of the crosslinking agent (E) is preferably 0.01 to 30% by mass, more preferably 0.05 to 20% by mass, and even more preferably 0.1 to 10% by mass, based on the total amount (100% by mass) of the resin composition layer. By setting the above content, the adhesion can be suitably adjusted.

[0098] [Other ingredients] The resin composition layer of this disclosure may contain other components, to the extent that it does not impair the purpose of this disclosure. For example, silane coupling agents, surface conditioning additives, curing accelerators, curing retarders, softeners, antistatic agents, lubricants, antiblocking agents, adhesion improvers, etc., can be added. From the viewpoint of improving adhesion to the glass substrate on which the microLED is mounted, it is preferable to include a silane coupling agent. Furthermore, if the resin (A) has polymerizable unsaturated bonds, monomers may be included so as to contribute to the formation of the resin composition layer.

[0099] Silane coupling agents are compounds in which hydrolyzable groups such as methoxy groups and ethoxy groups, and functional groups such as epoxy groups, are bonded to Si atoms via alkylene groups. Examples of silane coupling agents include, Alkoxysilane compounds having a (meth)acryloxy group, such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyltrippropoxysilane, 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, and N-phenyl-3-aminopropyltrimethoxysilane; Alkoxysilane compounds having a mercapto group, such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane; Alkoxysilane compounds having one epoxy group, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltributoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; Tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane; Examples include 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-isocyanatetopropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, hexamethyldisilazane, and silicone resins having alkoxysilyl groups in the molecule. From the viewpoint of adhesion, alkoxysilane compounds are preferred, and 3-glycidoxypropyltrimethoxysilane is more preferred. Furthermore, when using resin (A) having polymerizable unsaturated bonds, it is preferable to use alkoxysilane compounds having (meth)acryloxy groups.

[0100] A curing accelerator may be included to adjust the crosslinking rate of the resin composition layer of this disclosure. The curing accelerator is not particularly limited and can be selected as appropriate. Specific examples of curing accelerators include, for example, amine-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators.

[0101] As described above, the sealing sheet of this disclosure comprises a first film and a resin composition layer for forming a sealing layer laminated directly on the first film, and can be obtained by coating the first film with a coating liquid of the resin composition for forming the resin composition layer and drying it. Furthermore, in the case of a three-layer structure in which a first film, a resin composition layer for forming a sealing layer laminated directly on the first film, and a second film are laminated in this order, this can be achieved by coating the first film with a coating liquid of the resin composition for forming the resin composition layer, drying it, and then covering the surface of the resin composition layer with the second film, or by coating the second film with a coating liquid of the resin composition for forming the resin composition layer, drying it, and then covering the surface of the resin composition layer with the first film.

[0102] In industrial production, a long roll of first film is often unwound, a coating solution of the resin composition for forming the resin composition layer is applied to the unwound first film, dried, and a sealing sheet is formed. Alternatively, a long roll of second film is often unwound, a coating solution of the resin composition for forming the resin composition layer is applied to the unwound second film, dried, and then the long roll of first film is unwound, and the surface of the resin composition layer for forming the sealing layer is covered with the unwound first film to form a sealing sheet. Therefore, in the sealing sheet, the MD direction of the resin composition layer for forming the sealing layer coincides with the MD direction of the first film.

[0103] For coating, known coating machines and techniques such as comma coaters, die coaters, roll coaters, lip coaters, reverse coaters, gravure coaters, bar coaters, curtain coaters, dip coating, spin coating, silkscreen, and casting can be used. The solvent contained in the resin composition can be removed by a drying process after coating, and its amount can be adjusted to adjust the viscosity of the coating solution or the film thickness after drying. In a preferred embodiment, the resin composition can be applied to a support such as a first film, and then the applied film can be heated and dried using a hot air oven, infrared heater, or the like to form a resin composition layer on one surface of the support. Furthermore, to increase the crosslinking density of the resin composition layer, it is preferable to perform an aging treatment, such as leaving it to stand under specific temperature conditions, or to irradiate it with UV light. Alternatively, after coating, the resin composition may be transferred to another support such as a first film, second film, or substrate using a laminator. [Examples]

[0104] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not particularly limited to the examples. In the following description, "parts" and "%" refer to "parts by mass" and "% by mass," respectively, unless otherwise specified.

[0105] [Creation of the first film, etc. 1] Using the films shown below (F-1) to (F-9), 18 different types of release films (F-101) to (F-109) and (F-301) to (F-309) were prepared by varying the annealing temperature as described later. The results are shown in Table 1. (F-1) Therapyle BX9A-50μm (product name, manufactured by Toray Industries, Inc.) (F-2) Therapyle WZ-50μm (product name, manufactured by Toray Industries, Inc.) (F-3) Therapyle PJ271-50μm (product name, manufactured by Toray Industries, Inc.) (F-4) Therapyle TKA09-50μm (product name, manufactured by Toray Industries, Inc.) (F-5) Therapyle SY-50μm (product name, manufactured by Toray Industries, Inc.) (F-6) Therapyle BX9A-25μm (product name, manufactured by Toray Industries, Inc.) (F-7) Therapyle BX9A-100μm (product name, manufactured by Toray Industries, Inc.) (F-8) Therapyle BX9A-12μm (product name, manufactured by Toray Industries, Inc.) (F-9) Therapyle BX9A - 188μm (product name, manufactured by Toray Industries, Inc.)

[0106] [180°C annealing treatment] Each of the above-mentioned films (F-1) to (F-9), which are 500 mm long in the TD direction, was subjected to annealing using a reel-type film annealing device (manufactured by Shinko Seiki Co., Ltd.). Specifically, each of the above-mentioned films (F-1) to (F-9) was unwound and transported at a transport speed of 5 m / min inside a hot air heating furnace set to a heating temperature of 180°C. After transport, 100 mm was slit from both the left and right ends in the TD direction, and the central portion was wound up to obtain the first films (F-101) to (F-109). [110℃ annealing treatment] The first films (F-301) to (F-309) were produced using the same method as the 180°C annealing treatment, except that the heating temperature was changed to 110°C.

[0107] [Table 1]

[0108] [Production of the first film, etc. 2] [Preparation of release film] 100 parts by mass of methylvinylpolysiloxane, in which both ends of the molecular chain are sealed with dimethylvinylsiloxy groups; 5.2 parts by mass of methylvinylpolysiloxane having one branched chain and three molecular chain ends sealed with dimethylvinylsiloxy groups; 3.7 parts by mass of methylhydrogenpolysiloxane having twelve branched chains and both ends of the molecular chain sealed with trimethylsiloxy groups; further, 0.1 parts by mass of 1-ethynylcyclohexanol and 1.0 part by mass of phenyl group-containing organopolysiloxane were added, and the mixture was stirred until it was sufficiently homogeneous. Then, a platinum catalyst was added to a concentration of 50 ppm of platinum relative to the total solid content to prepare a stripping agent.

[0109] The aforementioned release agent was applied to the first surface of the following film (F-10): Toyobo ester film G2LA (product name, manufactured by Toyobo Co., Ltd.) so that the thickness after drying was 100 nm. After heating in an oven at 110°C for 20 seconds, the film was left to stand at 25°C for 1 day to obtain a releaseable film (F-210). Instead of (F-10), (F-11) and (F-12) below were used to obtain the peelable films (F-211) and (F-212), respectively. (F-10) Toyobo Ester Film G2LA - 50μm (Product name, manufactured by Toyobo Co., Ltd.) (F-11) Pyrene film OT P2161 - 50μm (product name, manufactured by Toyobo Co., Ltd.) (F-12) Pyrene film CT P1128 - 50μm (product name, manufactured by Toyobo Co., Ltd.)

[0110] [Production of the first film, etc. 3] Instead of (F-1) Therapyel BX9A-50μm (product name, manufactured by Toray Industries, Inc.), (F-11) Pyrene film OT P2161-50μm (product name, manufactured by Toyobo Co., Ltd.) was used and annealed at 180°C or 110°C, respectively, to obtain films (F-111) and (F-311) that do not have peelability. The non-peelable films (F-111) and (F-311) obtained were each coated with the release agent in the same manner as described above to form a release layer, thereby obtaining peelable films (F-213) and (F-413), respectively. The results are shown in Table 2.

[0111] [Table 2]

[0112] [Shrinkage rate in the MD direction of the first film, etc. [%]] As shown in Figure 3(a), the first film 12 was cut to a size of 200 mm in the MD direction and 20 mm in the TD direction to obtain a measurement sample. Next, marks were made on the measurement sample at positions 10 mm perpendicular to the long side and 25 mm perpendicular to the short side, with one mark designated as A and the other as B. Before heating, the distance between A and B on the measurement sample was measured using a digital long scale LS450E (manufactured by Protec Engineering Co., Ltd.). Next, a clip was attached to the A end of the sample, and it was suspended with A at the top and B at the bottom. It was then placed in a 150°C oven and heated for 120 minutes. As shown in Figure 3(b), the distance between A and B of the first film 12' after heating was measured. The distance between A and B before heating was defined as (AB)0, and the distance after heating at 150°C for 120 minutes was defined as (AB)0. 150 The value represented by the following formula (2) was defined as the MD direction shrinkage rate [%]. 100 × ((AB)0 - (AB) 150 ) / (AB)0) (2)

[0113] [Storage modulus E' of the first film at 150°C] 150 [Pa]] The storage modulus E' of each film obtained in steps 1-3 of the first film preparation was measured using a dynamic viscoelasticity measuring device DVA-200 (manufactured by IT Measurement Control Co., Ltd.) in accordance with JIS K7198. The measurement samples used were each film cut to 5 mm in the transverse direction (hereinafter referred to as the TD direction) and 30 mm in the MD direction. The deformation mode was tensile, with a strain of 0.08%, a frequency of 10 Hz, a heating rate of 10 °C / min, and measurements taken in a temperature range of 20 to 200 °C. From the obtained data, the storage modulus E' at a temperature of 150 °C was read, and E' 150 That's what I decided.

[0114] [Preparation of resin compositions for forming sealing layers] <Manufacturing and preparation of resin (A)> [Example of preparation of (meth)acrylic resin (a1-1) solution] In a reaction vessel (hereinafter simply referred to as "reaction vessel") equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, 80 parts ethyl acetate, 2 parts methyl acrylate, 32 parts methyl methacrylate, 60 parts 2-ethylhexyl methacrylate, 3 parts methacrylic acid, and 0.1 parts 2,2'-azobisisobutyronitrile as an initiator were charged, and the atmosphere in the reaction vessel was replaced with nitrogen gas. Then, under a nitrogen atmosphere, the mixture was heated to 75°C with stirring to start the reaction. The reaction solution was then reacted at 75°C for 4 hours. After the reaction was complete, it was cooled and diluted with ethyl acetate to obtain a (meth)acrylic resin (a1-1) intermediate solution. To the obtained intermediate solution, 3 parts glycidyl methacrylate was added as a modifying agent, and the mixture was stirred at 60°C for 24 hours. Dilution with ethyl acetate as needed was then used to produce a (meth)acrylic resin (a1-1) solution having a methacryloyl group. The weight-average molecular weight (Mw) and solid content were determined using the method described later to be 110,000 and 25%, respectively.

[0115] [Example of preparation of (meth)acrylic resin (a1-2) solution] An intermediate solution of (meth)acrylic resin (a1-2) was obtained by the same method as in the production of (meth)acrylic resin (a1-1), except that the monomer composition was 3 parts n-butyl acrylate, 50 parts n-butyl methacrylate, 40 parts 2-ethylhexyl methacrylate, and 5 parts 2-hydroxyethyl methacrylate. Two parts of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resonaq) were added to the obtained intermediate solution as a modifier, and a solution of (meth)acrylic resin (a1-2) was produced by the same method as in the production of (meth)acrylic resin (a1-1). The (Mw): 120,000 and solids content: 25%.

[0116] [Example of preparing a solution of urethane resin (a2)] A solution (solids content: approximately 25%) of the carboxyl group-containing polyurethane resin "VA-9320" (manufactured by Toyo Chem Co., Ltd.) was prepared.

[0117] [Example of epoxy resin (a3) ​​solution preparation] Teisan Resin SG-80H (manufactured by Nagase ChemteX Corporation), with a weight-average molecular weight (Mw) of 350,000, was diluted with ethyl acetate to prepare a solution of epoxy resin (a3) ​​with a solid content of approximately 25%.

[0118] [Weight average molecular weight (Mw)] The weight-average molecular weight (Mw) was determined by using the Shimadzu GPC "LC-GPC system" (instrument name) and converting it using polystyrene with a known molecular weight as a standard substance. Equipment name: Shimadzu Corporation, LC-GPC system "Prominence" Columns: Four Tosoh GMHXL columns and one Tosoh HXL-H column were connected together. Mobile phase solvent: tetrahydrofuran Flow rate: 1.0mL / min Column temperature: 40℃

[0119] [Solid content] The mass (W0) of the aluminum cup was weighed using a precision balance. Next, approximately 1 g of the sample was placed in the aluminum cup, and the mass of the sample in the aluminum cup (W1) was weighed using a precision balance. The sample in the aluminum cup was heated in a 150°C oven for 120 minutes, then removed from the oven and allowed to return to room temperature. The residual mass (W2) of the heated sample in the aluminum cup was weighed using a precision balance. The solid content was then calculated using the formula (W2-W0) / (W1-W0)×100(%).

[0120] [Preparation of resin compositions for forming sealing layers] To 100 parts by mass of (meth)acrylic resin (a1-1) solids, 20 parts by mass of Mitsubishi Carbon MA100 as a coloring agent (Q-1), 5 parts by mass of Solsperse 5000 as a dispersant (D-1), and 200 parts by mass of methyl isobutyl ketone as a solvent were mixed in a 0.45 L container and pre-dispersed with a disperser. Then, 1300 parts by mass of 1.0 mm diameter zirconia beads were added, and the mixture was fully dispersed for 1 hour using a shaker (Scandex SK450: manufactured by Fast & Fluid Management). The zirconia beads were then removed to obtain a black dispersion. To the obtained black dispersion, 5 parts by mass of Luperox 230 (trade name, manufactured by Arkema Yoshitomi Co., Ltd.) as a polymerization initiator (B-1) and 38 parts by mass of a diluent (methyl ethyl ketone, toluene mixed solvent) were sequentially added while stirring with a disperser. The mixture was then stirred until it was sufficiently homogeneous to obtain a black coating liquid (1) for forming a resin composition layer for sealing layer formation.

[0121] [Example 1] The coating liquid (1) was applied to the release layer of a Therapiel BX9A (product name, manufactured by Toray Industries, Inc.) annealed product as the first film (F-101) so that the thickness after drying would be 25 μm, and the film was heated and dried in a hot air oven at 80°C to obtain a sealing sheet in which a resin composition layer for forming a sealing layer was formed on the first film.

[0122] [Examples 2-7, 13-17, 23-24, Comparative Examples 1-14] As shown in Tables 3-5, a black coating solution was prepared and a sealing sheet was obtained in the same manner as in Example 1, except that the first film (F-101) was changed.

[0123] [Example 8] As shown in Table 3, a white coating solution was prepared in the same manner as in Example 1, except that (meth)acrylic resin (a1-2) was used instead of (meth)acrylic resin (a1-1), Typake CR-97 was used as the coloring agent (Q-2) instead of the coloring agent (Q-1), and DISPEARBY K142 was used as the dispersant (D-2) instead of the dispersant (D-1), and a sealing sheet was obtained.

[0124] [Example 18] As shown in Table 4, a white coating solution was prepared and a sealing sheet was obtained in the same manner as in Example 8, except that the first film (F-101) was changed.

[0125] [Example 9] As shown in Table 3, to 100 parts by mass of (meth)acrylic resin (a1-2) solids, 5 parts by mass of Luperox 230 (manufactured by Arkema Yoshitomi Co., Ltd.) as a polymerization initiator (B) and 38 parts by mass of a diluent (methyl ethyl ketone, toluene mixed solvent) were sequentially added while stirring with a disperser, and the mixture was stirred until it was sufficiently homogeneous to prepare a colorless coating solution, and a sealing sheet was obtained in the same manner as in Example 1.

[0126] [Example 19] As shown in Table 4, a colorless coating solution was prepared in the same manner as in Example 9, except that the first film (F-101) was changed, and a sealing sheet was obtained.

[0127] [Example 10] As shown in Table 3, a high refractive index coating solution was prepared in the same manner as in Example 1, except that (meth)acrylic resin (a1-2) was used instead of (meth)acrylic resin (a1-1), PCS-60 was used as an inorganic filler (P-1) instead of the colorant (Q-1), and DISPEARBYK142 was used as a dispersant (D-2) instead of the dispersant (D-1), and a sealing sheet was obtained.

[0128] [Example 20] As shown in Table 4, a high refractive index coating solution was prepared in the same manner as in Example 10, except that the first film (F-101) was changed, and a sealing sheet was obtained.

[0129] [Example 11] As shown in Table 3, a black coating solution was prepared and a sealing sheet was obtained in the same manner as in Example 1, except that urethane resin (a2) was used instead of (meth)acrylic resin (a1-1) and jER YX8034 was used as a crosslinking agent (E-1) instead of polymerization initiator (B).

[0130] [Example 21] As shown in Table 4, a black coating solution was prepared and a sealing sheet was obtained in the same manner as in Example 11, except that the first film (F-101) was changed.

[0131] [Example 12] As shown in Table 3, a black coating solution was prepared and a sealing sheet was obtained in the same manner as in Example 1, except that epoxy resin (a3) ​​was used instead of (meth)acrylic resin (a1-1) and Cureazole C11Z-A was used as a crosslinking agent (E-2) instead of polymerization initiator (B).

[0132] [Example 22] As shown in Table 4, a black coating solution was prepared and a sealing sheet was obtained in the same manner as in Example 12, except that the first film (F-101) was changed. The initiators, crosslinking agents, inorganic fillers, colorants, and dispersants used are described below. <Initiator> (B-1) Luperox 230 (product name, manufactured by Arkema Yoshitomi Co., Ltd.) <Crosslinking agent> (E-1) jER YX8034 (product name, manufactured by Mitsubishi Chemical Corporation) (E-2) Curazol C11Z-A (product name, manufactured by Shikoku Chemicals Co., Ltd.) <Inorganic filler> (P-1)PCS-60 (product name, manufactured by Nippon Denko) <Coloring agent> (Q-1) Mitsubishi Carbon MA100 (product name, manufactured by Mitsubishi Chemical Corporation) (Q-2) Typeque CR-97 (product name, manufactured by Ishihara Sangyo Co., Ltd.) <Dispersant> (D-1) Solsperse 5000 (product name, manufactured by Lubrizol) (D-2) DISPEARBYK142 (product name, manufactured by BYK)

[0133] [Thickness T of sealing sheet] t , thickness T of the resin composition layer a [First film thickness T1, second film thickness T2] A test specimen was prepared by laminating the first film, the resin composition layer, and the second film in the order of the first film, the resin composition layer, and the second film using a 90°C laminator. The above test specimen was cut to a size of 100 mm x 100 mm. The second film was peeled off the sealing sheet, and 10 points were determined at equal intervals from one end to the other in the width direction of the second film. The thickness of these 10 points was measured, and the average value was defined as the thickness T2 of the second film. Next, the thickness of the sealing sheet was measured at 10 points corresponding to the same positions as above. The average value was defined as T2. t The first film was then peeled from the resin composition layer, and the thickness of the peeled first film was measured at 10 locations corresponding to the same positions as described above. The average value was defined as T1. Thickness T of the resin composition layer a is, T a =T t The value was calculated using the formula -T1. The thickness was measured using an MH-15M (Nikon Corporation). For the second film, (f-1)SP-PET-O1-BU6 (product name, manufactured by Mitsui Chemicals ICT Materia Co., Ltd.) was used.

[0134] [Peel strength P1 of the first film, and peel strength P2 of the second film] A second film was laminated to the resin composition layer side of the sealing sheet and pressed tightly using a laminator. With the first film, resin composition layer, and second film laminated in this order, two strips measuring 25 mm in the TD direction and 100 mm in the MD direction were cut to prepare test specimens. The second film was peeled off the first test specimen, and the exposed resin composition layer was attached to a stainless steel plate (hereinafter abbreviated as "SUS plate") with double-sided tape applied to it to obtain a measurement sample for measuring the peeling force of the first film. Next, the first film side of the second test specimen was attached to the SUS plate with double-sided tape applied to it to obtain a measurement sample for measuring the peeling force of the second film. For each sample, the peeling force P1 of the first film and the peeling force P2 of the second film [mN / 25mm] were measured in a 23°C atmosphere, in accordance with JIS Z 0237:2009, when peeled at a speed of 300 mm / min in a 180° direction. The peeling force was measured using STB-125S (product name, manufactured by AND Corporation).

[0135] [evaluation] Unless otherwise specified, all evaluations were categorized as follows: AA: Excellent, A: Good, B: Practical, and C: Failed to meet target performance. The evaluation results for each example and comparative example are shown in Tables 3 to 5.

[0136] <Appearance evaluation of the cured resin composition layer> A sealing sheet with a second film was cut to a size of 50 mm x 50 mm, the second film was peeled off, and the resin composition layer side was placed on the first surface of a blue glass plate (manufactured by Kawamura Kyuzo Shoten Co., Ltd.) measuring 80 mm x 80 mm x 1.1 mm. Then, as cushioning material, a 50 μm thick TPX (Opulan X-44B, product name, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) and a 2 mm thick PVC film (Celeb T, manufactured by Okamoto Co., Ltd.) were placed in order on top of the first film, and cardboard was placed on top to prevent sticking. The laminate consisting of blue glass plate / resin composition layer / first film / cushioning material (TPX / PVC film) / cardboard was pressed from above against the substrate surface at 3 MPa and 100°C for 10 minutes to adhere the resin composition layer to the blue glass plate. After pressing, the cushioning material and cardboard were peeled off. The resulting test sample, consisting of the first film, the resin composition layer, and the blue glass plate, was placed horizontally in a 150°C oven and heated for 120 minutes. After heating, the surface appearance of the hardened resin composition layer was visually evaluated after peeling off the first film. Appearance defects were defined as zip marks caused by peeling the heated first film from the hardened resin composition layer, marks transferred from the press plate pattern to the hardened resin composition layer, and marks transferred from the deflection caused by the hardening shrinkage of the first film. The appearance evaluation was performed according to the following criteria. • Evaluation criteria AA: Total of one or fewer cosmetic defects. A: There are two or more but no more than four defects in the exterior appearance. B: There are a total of 5 to 7 defects in the exterior appearance. C: There are a total of 8 or more defects in the exterior appearance.

[0137] <Seamlessness> As shown in Figure 4(a), the sealing sheet with the second film was cut to a size of 50 mm x 50 mm, the second film was peeled off, and the resin composition layer 11 side was placed on the first surface of a blue glass substrate 22 (manufactured by Kawamura Kyuzo Shoten Co., Ltd.) measuring 80 mm x 80 mm x 1.1 mm. Then, as cushioning material, a 50 μm thick TPX (Opulan X-44B, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) and a 2 mm thick PVC film (Celeb T, manufactured by Okamoto Co., Ltd.) were placed in order on the first film 12, and cardboard was placed on top to prevent sticking. The laminate consisting of the blue glass substrate 22 / resin composition layer 11 / first film 12 / cushioning material (TPX / PVC film) / cardboard was pressed from above against the blue glass substrate surface 22 at 3 MPa and 100°C for 10 minutes to adhere the resin composition layer 11 to the blue glass substrate 22. After pressing, the cushioning material and cardboard were peeled off. The test sample, which consisted of the obtained first film 12, the resin composition layer 11, and the blue glass substrate 22, was placed horizontally in a 150°C oven and heated for 120 minutes. Then, in order to observe the cross-section of the cured resin composition layer 11', the heated first film 12' was cut in half parallel to the MD direction at a position 30 mm from the TD direction edge of the heated first film 12', while the heated first film 12' was still attached. The heated first film 12' was peeled off, and the cross-section of the cut fragment with the cured resin composition layer 11' exposed was observed using a laser microscope VK-X100 (product name, manufactured by KEYENCE). As shown in Figure 4(b), the position of the lower edge of the cured resin composition layer 11' (i.e., the edge of the cured resin composition layer 11' in contact with the blue glass substrate 22) was defined as H1, and the position 100 μm from H1 toward the cured resin composition layer 11' in the MD direction (i.e., on the surface of the cured resin composition layer 11' in contact with the blue glass substrate 22) was defined as H2. The intersection point of the cured resin composition layer 11' with a straight line drawn perpendicular to the surface of the blue glass substrate 22 from H2 was defined as H3. The distance T between H2 and H3 at this time X The thickness (μm) was determined, and the film thickness retention rate was calculated using the following equation (3). (T X / T a ) × 100 (3) The seamlessness of arranging multiple panels based on the value of equation (3) was evaluated according to the following criteria. • Evaluation criteria AA: The value of equation (3) is 50 or greater. A: The value of equation (3) is 20 or greater and less than 50. B: The value of equation (3) is 10 or greater, and less than 20. C: The value of equation (3) is less than 10.

[0138] <Embedding> A embedded substrate 23 was prepared to mimic the uneven surface of a micro-LED substrate (a glass plate measuring 25 mm x 25 mm, on one side of which multiple recesses with a width of 200 μm, a height of 5 μm, and a width of 200 μm were formed in a grid pattern). A schematic cross-sectional view of the embedded substrate 23 is shown in Figure 5. A sealing sheet with a second film was cut to a size of 30 mm x 30 mm, the second film was peeled off, and the resin composition layer side was placed on the surface of the test substrate where the uneven areas were formed. Then, a 50 μm thick TPX (Opulan X-44B, trade name, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) and a 2 mm thick PVC film (Celeb T, manufactured by Okamoto Co., Ltd.) were placed in order on top of the first film as cushioning material, and cardboard was placed on top to prevent sticking. The laminate consisting of glass substrate / resin composition layer / first film / cushioning material (TPX / PVC film) / cardboard was pressed from above against the substrate surface at 3 MPa and 100°C for 10 minutes, and a sealing layer was formed by filling the recesses of the test substrate with the resin composition layer. After pressing, the cushioning material and cardboard were peeled off. The four corners of 15 arbitrary recesses (60 locations in total) of the obtained sealing layer and the test substrate with the first film were observed under a microscope from the glass plate side, and the embedding ability was evaluated based on the number of locations where gaps occurred, according to the following criteria. • Evaluation criteria AA: There are 56 or more places with no gaps. A: There are 41 or more, and 55 or fewer, areas without gaps. B: There are 29 or more, and 40 or fewer, recessed areas without gaps. C: There are 28 or fewer recessed areas without gaps.

[0139] [Table 3]

[0140] [Table 4]

[0141] [Table 5] [Explanation of symbols]

[0142] 11: Resin composition layer 11': Cured resin composition layer 12: First Film 12': First film after heating 13: Second film 20: Micro LED element 21: Circuit board 22: Blue glass substrate 23: Embedded circuit board

Claims

1. A sealing sheet for sealing an optical semiconductor used in a display that uses an optical semiconductor as a light source, The sealing sheet comprises a first film and a resin composition layer for forming a sealing layer, which is laminated directly on the first film. The shrinkage rate of the first film, measured under the following conditions, was 1.2% or less: The first film, in its unheated state, is heat-treated at 150°C for 120 minutes, and the longitudinal shrinkage rate of the first film after the heat treatment is measured. The storage modulus of the first film at 150°C in the tensile mode is E' １５０ [×10 ８ Pa], the thickness of the first film is T ｌ When the value is [μm], the following equation (1) is satisfied, 40 ≦ (E’ １５０ ) １／２ × T ｌ ≦ 230 (1) The peeling force P between the first film and the resin composition layer ｌ The values ​​are 8-150 mN / 25 mm. The thickness T of the first film １ The sealing sheet is characterized by having a thickness of 20 to 120 μm.

2. The sealing sheet according to claim 1, characterized in that the first film is a biaxially oriented polyester film or a biaxially oriented polyolefin film.

3. The sealing sheet according to claim 2, characterized in that the shrinkage rate of the first film is 1.0% or less.

4. The sealing sheet according to claim 1, characterized in that the first film is an annealed product.

5. The sealing sheet according to claim 1, characterized in that the resin composition layer contains at least one selected from the group consisting of (meth)acrylic resin, epoxy resin, and urethane resin.

6. The sealing sheet according to claim 5, characterized in that it contains 50% or more (meth)acrylic resin when the solid content of the resin composition layer is 100% by mass.

7. The sealing sheet according to claim 1, characterized in that the optical semiconductor is a microLED.

8. A display comprising a sealing layer which is a cured resin composition layer according to any one of claims 1 to 7.

9. A method for manufacturing a sealing sheet for sealing an optical semiconductor used in a display that uses an optical semiconductor as a light source, The sealing sheet comprises a first film and a resin composition layer for forming a sealing layer, which is laminated directly on the first film. The shrinkage rate of the first film, measured under the following conditions, was 1.2% or less: The first film, in its unheated state, is heat-treated at 150°C for 120 minutes, and the longitudinal shrinkage rate of the first film after the heat treatment is measured. The storage modulus at 150°C in the tensile mode of the first film is E' １５０ [×10 ８ Pa], and it satisfies the following formula (1): 40 ≦ (E’ １５０ ) １／２ × T ｌ ≦ 230 (1) The peeling force P between the first film and the resin composition layer ｌ The values ​​are 8-150 mN / 25 mm. The thickness T of the first film １ The size is 20-120 μm. A method for manufacturing a sealing sheet, characterized by the following:

10. The method for manufacturing a sealing sheet according to claim 9, wherein the first film is subjected to an annealing treatment.

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