Encapsulating sheet and display having resin composition layer

Abstract

Provided are an encapsulating sheet that is less likely to cause thickness unevenness or poor appearance at the ends of a resin composition layer and is less likely to cause voids at the bottom or corners of a recess, a manufacturing method thereof, and a display using the same. [Solution] An encapsulating sheet for encapsulating an optical semiconductor used in a display using an optical semiconductor as a light source, the encapsulating sheet comprising a first film and a resin composition layer for forming an encapsulating layer laminated directly on the first film, the shrinkage percentage of the first film measured under conditions described in the specification being 1.2% or less, and the first film having a storage modulus of E' at 150°C in a tensile mode of the first film. 150 [×10 8 Pa], the thickness of the first film is T l [μm], 40≦(E' 150 ) 1 / 2 ×T l ≦230, and the peel strength P between the first film and the resin composition layer is l The encapsulating sheet has a strength of 8 to 150 mN / 25 mm and a thickness T1 of the first film of 20 to 120 μm.

Description

[Technical Field]

[0001] The present disclosure relates to an encapsulating sheet, and more particularly to an encapsulating sheet including a resin composition layer for encapsulating a micro LED used in a display using a micro LIGHT emitting diode (hereinafter abbreviated as LED) as a light source, a method for producing the same, and a display having an encapsulating layer formed from the resin composition layer. [Background technology]

[0002] In recent years, development of displays (display panels) using various light-emitting elements has been actively pursued in order to further improve their performance. Specifically, various display specifications are being researched, including backlit displays using liquid crystal or quantum dots, displays using optical semiconductors such as mini / micro LEDs and organic electroluminescence (EL), plasma displays, and electrophoretic displays. These displays are being considered for a wide range of uses, from large displays such as signage and televisions to small displays such as tablets, personal computers, smartphones, and wearable devices. In particular, development of displays using micro LEDs is progressing at an increasing pace, and the development of encapsulating sheets for encapsulating multiple LED elements is attracting attention. Patent Document 1 proposes a semiconductor encapsulating sheet that contains an epoxy resin and is characterized by undergoing a filling step at 65° C. and a heat aging step at 150° C. The encapsulating material in this document states that adding an inorganic filler can suppress shrinkage of the resin. Patent Document 2 proposes a dry film for sealing optical semiconductors. The document describes that the sealing material suppresses warping and prevents burrs and chips during dicing by making the maximum diameter of aggregated particles of inorganic filler equal to or less than half the thickness of the resin composition layer. Patent Document 3 proposes a sheet for encapsulating an optical semiconductor element, which includes a diffusion layer and an antireflection layer. The document describes that the encapsulant in this document allows for the manufacture of an optical semiconductor device with reduced color cast while improving the antireflection function and contrast of metal wiring and the like, by controlling the total light transmittance and haze value of the diffusion layer and the antireflection layer so as to have a specific relationship. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-197495 [Patent Document 2] International Publication No. 2020 / 195843 [Patent Document 3] Japanese Patent Publication No. 2023-024316 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, with the need for larger displays, a method of manufacturing a single large panel by arranging and joining multiple display panels has attracted attention. Furthermore, the functions required vary widely depending on the type of display. The development of encapsulating sheets for encapsulating optical semiconductors arranged in such displays is progressing daily. However, while conventional encapsulating sheets have excellent heat resistance, impact resistance, and embeddability, they have sometimes had the following problems. After the encapsulating sheet is subjected to a heat pressing and heat aging process, shrinkage of the first film causes thickness unevenness at the edge of the resin composition layer. This can make the seams of the panels conspicuous when multiple display panels are arranged and joined together (hereinafter also referred to as seamlessness). Furthermore, the rigidity of the first film can sometimes impair the embeddability of the encapsulating sheet (hereinafter also referred to as embeddability). Furthermore, when the encapsulating sheet is heat pressed, the pattern of the upper plate of the heat press machine is transferred to the resin composition layer, and when the first film is peeled off after the heat aging process, zipping marks remain on the resin composition layer, resulting in poor appearance and one of the causes of low yields.

[0005] The present disclosure aims to provide an encapsulating sheet that is less likely to have uneven thickness at the ends of a resin composition layer, is less likely to have poor appearance, and is less likely to have voids at the bottom surface or corners of a recess, a manufacturing method thereof, and a display using the same. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems, and as a result have arrived at the inventions described in [1] to

[10] below. That is, [1]: An encapsulating sheet for encapsulating an optical semiconductor used in a display using an optical semiconductor as a light source, the encapsulating sheet comprising a first film and a resin composition layer for forming an encapsulating layer laminated directly on the first film, wherein 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 in the longitudinal direction of the first film after the heat treatment is measured; and the storage modulus of the first film at 150°C in a tensile mode of the first film is E' 150 [×10 8 Pa], the thickness of the first film is T l [μm], the following formula (1) is satisfied, and 40 ≦ (E' 150 ) 1 / 2 × T l ≦ 230 (1), the peel strength P between the first film and the resin composition layer l The encapsulating sheet is characterized in that the strength of the first film is 8 to 150 mN / 25 mm, and the thickness T1 of the first film is 20 to 120 μm.

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

[0008] [8]: A display comprising 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 producing an encapsulating sheet for encapsulating an optical semiconductor used in a display using an optical semiconductor as a light source, the encapsulating sheet comprising a first film and a resin composition layer for forming an encapsulating layer laminated directly on the first film, wherein 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 a tensile mode of the first film is E' 150 [×10 8 Pa], the following formula (1) is satisfied, and 40 ≦ (E' 150 ) 1 / 2 × T l ≦ 230 (1), the peel strength P between the first film and the resin composition layer l is 8 to 150 mN / 25 mm, and the first film thickness T1 is 20 to 120 μm.

[10] : The method for producing an encapsulating sheet according to [9], wherein the first film is subjected to an annealing treatment. [Effects of the Invention]

[0010] The present disclosure makes it possible to provide an encapsulating sheet that is less likely to have uneven thickness at the ends of an encapsulating resin composition layer, is less likely to have poor appearance, and is less likely to have voids at the bottom or corners of a recess, a manufacturing method thereof, and a display using the same. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic cross-sectional view showing an example of a laminated structure of an encapsulating sheet. [Figure 2] 10A to 10C are schematic cross-sectional views showing a step of sealing an optical semiconductor element on a substrate having a light-emitting element. [Figure 3]FIG. 2 is a schematic diagram illustrating a method for evaluating the shrinkage rate in the MD direction of the first film. [Figure 4] FIG. 1 is a schematic diagram for explaining a method for evaluating seamlessness in an example. [Figure 5] FIG. 1 is a cross-sectional view showing an example of a test substrate that mimics a micro LED substrate. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described in detail below. Note that the embodiments described below are examples of the present disclosure. The present disclosure is not limited to the following embodiments, and includes modifications that are implemented within the scope of the present disclosure. In this specification, a numerical range specified using "to" includes the numerical values ​​before and after "to" as the lower and upper limits of the range. In numerical ranges described in stages in this specification, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in numerical ranges described in this specification, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. Furthermore, (meth)acrylic acid refers to either acrylic acid or methacrylic acid, or both. Unless otherwise noted, the various components appearing in this specification may be used independently as a single type or in combination of two or more types. When two or more types are used in combination, the total content is used.

[0013] [Form of encapsulating sheet] As shown in FIG. 1(a), the encapsulating sheet of the present disclosure includes a first film 12 and a resin composition layer 11 for forming an encapsulating layer laminated directly on the first film 12. The first film 12 can be a low-shrinkage film. The resin composition layer 11 can be provided in a plurality of layers. When the encapsulating sheet has the two-layer structure shown in FIG. 1(a), a manufacturing method in which the resin composition layer 11 is formed on the first film 12 is preferred. 1(b), a three-layer structure may be formed by laminating 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 in this order. In this case, multiple resin composition layers 11 may be provided. When the three-layer structure shown in FIG. 1(b) is formed, the resin composition layer 11 may be formed on the second film 13, and then the first film 12 may be laminated thereto, or the resin composition layer 11 may be formed on the first film 12, and then the second film 13 may be laminated thereto. The latter manufacturing method is preferred. After or during the production of the encapsulating sheet, the encapsulating sheet is wound around a core in a roll shape to obtain an encapsulating sheet roll. The winding length can be designed depending on the application. From the viewpoint of increasing productivity, the winding length is preferably 50 m or more, more preferably 100 m or more. From the viewpoint of production yield, the winding length is preferably 10,000 m or less. When the encapsulating sheet is in the form of a roll, it is preferable to provide the first film on the inside of the winding.

[0014] The encapsulating sheet of the present disclosure is used to seal between display elements that use multiple optical semiconductors as light sources. The optical semiconductors are preferably micro LEDs, and the emitted color thereof is not particularly limited, but examples thereof include red, green, and blue. The encapsulating sheet of the present disclosure is preferably used to seal a micro LED array in which a large number of elements of the three colors are regularly arranged on a substrate. That is, the encapsulating sheet of the present disclosure is preferably used to seal between red (R) elements and green (G) elements, between G elements and blue (B) elements, between B elements and R elements, or between [R element, G element, B element] units. The resin composition layer is preferably directly attached to the micro LED for sealing. The micro LED is preferably disposed on a substrate made of, but not limited to, acrylic, urethane, polycarbonate, epoxy, polyimide, glass, paper, cloth, aluminum, resist, ceramic, or polyethylene terephthalate, and has an electrode portion.

[0015] The resin composition layer has high conformability to uneven surfaces, so it is suitable for use in conforming to the micro LEDs and filling 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. The sealing layer may also have other functionalities, such as light diffusion prevention, light blocking, shielding, light leakage prevention, low shrinkage, wavelength conversion, light reflectivity, high refractive index, low refractive index, and heat dissipation. In the present disclosure, the term "resin composition layer" refers to any layer formed from the resin (A) described below, and can refer to any of a state in which the layer is formed on a first film or other arbitrary support, a single layer state, and a state in which the layer seals between multiple optical semiconductor elements. On the other hand, the term "encapsulating layer" particularly refers to a layer formed when the resin composition layer is used to seal between multiple optical semiconductor elements. Further, in this specification, the encapsulating sheet according to the present disclosure may include an unheated state (before heat treatment) or a heated state (during and after heat treatment). That is, the first film and the resin composition layer (for forming the encapsulating layer) in the present disclosure may both be in an unheated state (before heat treatment) or a heated state (during and after heat treatment). Therefore, it can be said that the above-mentioned encapsulating layer is one form (cured product) of the resin composition layer. Micro LEDs are tiny optical semiconductors measuring 50 μm or less or 100 μm or less. By mounting multiple micro LEDs on a substrate with wiring and circuits, a display using multiple optical semiconductors as light sources is formed. Micro LEDs are made up of optical semiconductors such as GaAs, GaP, AlGaInP, and InGaN, a resin composition layer that encapsulates them, a package substrate, electrodes, etc., and have an operating temperature of 25 to 60°C. An example of the process for forming the resin composition layer will be described below with reference to FIG. Although not shown, a step preceding step (a) shown in FIG. 2 can be a step of preparing an object to be sealed, in which multiple micro LEDs are arranged at intervals on one side of a substrate.

[0016] Step (a): Step of placing the encapsulating sheet As shown in FIG. 2(a), the surface of the encapsulating sheet according to the present disclosure on which the resin composition layer 11 is exposed is placed on a substrate 21 having a plurality of micro LED elements 20 so as to directly cover the entirety of the plurality of micro LED elements 20. In this specification, there is no particular limitation on the number of micro LED elements 20. In display applications, the number of micro LED elements 20 used is determined by the display size and the number of pixels. The size of the micro LED element 20 is 100 μm or less in thickness and 40,000 μm in plan view area. 2 The following is preferable: a thickness of 50 μm or less and an area in plan view of 10,000 μm 2 The following is more preferable: a thickness of 20 μm or less and a planar area of ​​2,500 μm 2 The following are even more preferred: The interval between the micro LED elements 20 mounted on the substrate 21 is, for example, 10 to 5,000 μm. When a set of red, green, and blue micro LED elements 20 is mounted on the substrate 21 as one pixel, the interval between the pixels is, for example, 10 to 2,000 μm, preferably 20 to 1,800 μm, and more preferably 500 to 1,500 μm. The interval between the micro LED elements 20 within one 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 Fig. 2(b), for example, the resin composition layer 11 is fluidized by pressing and filled around the micro LED elements 20 and between the micro LED elements 20. The resin composition layer 11 filled around the micro LED elements 20 and between the micro LED elements 20 serves as a sealing layer. There are no particular limitations on the pressing method, but heat pressing and vacuum pressing are preferred. From the viewpoint of the filling ability of the resin composition layer 11, the temperature during pressing 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 carry out the filling step 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 step, because this prevents the pattern on the upper plate of the press from being transferred to the resin composition layer, thereby enabling the formation of a uniform resin composition layer.

[0018] Step (c): Heat aging step To improve adhesion between the micro LED element 20 and the substrate 21, heat aging may be performed after pressing, as shown in FIG. 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 heated first film 12' may be peeled off before or after heat aging, but peeling after heat aging is more preferable. Heat aging may be performed after steps (d-1) and (d-2), which will be described later. When steps (d-1) and (d-2) are performed before heat aging, it is preferable to peel off the first film 12 or the heated first film 12' before the etching step.

[0019] Step (d-1) or (d-2): Etching step In step (d-1) or (d-2), etching may be performed as needed to remove or thin the resin composition layer 11 or cured resin composition layer 11' on the micro LED element 20. If step (d-1) or (d-2) is performed, it is preferable to perform it after peeling off the first film 12 or the heated first film 12'. Removing excess resin composition layer 11 or cured resin composition layer 11' improves the brightness of the micro LED element 20 and ensures visibility during emission. The thickness of the resin composition layer 11' after etching and heating is preferably approximately the same as the thickness of the micro LED element 20, as shown in FIG. 2(d-1), or less than the thickness of the micro LED element 20, as shown in FIG. 2(d-2). In other words, the difference between step (d-1) and step (d-2) is the amount of etching. It is not necessary to completely remove the cured resin composition layer 11' from the micro LED element 20; it is sufficient to substantially remove it, and some thin film may remain. 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 chemicals, physical polishing using an abrasive, 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, it is preferable to use plasma etching or a combination of wet etching and dry etching. The plasma etching conditions may be, for example, dry etching in an anisotropic plasma device using a CF4 / O2 / N2 mixed gas at an output of 1500-3000 W for 180-600 seconds, with the CF4 gas supply rate being, for example, 50-100 sccm, the O2 gas supply rate being, for example, 500-1000 sccm, and the N2 gas supply rate being, for example, 50-100 sccm.

[0020] As described above, the encapsulating layer can be formed from the resin composition layer in the encapsulating sheet of the present disclosure through steps (a) to (d-1) or steps (a) to (d-2). Note that the above steps may be repeated to laminate multiple layers. As described above, the sealing sheet of the present disclosure comprises a first film and a resin composition layer (dried product, solidified product) for forming a sealing layer laminated directly on the first film, and can be obtained by applying a coating liquid of a resin composition for forming the resin composition layer onto the first film and drying it. Furthermore, when a three-layer structure is formed by laminating a first film, a resin composition layer for forming a sealing layer laminated directly on the first film, and a second film in this order, the structure can be obtained by applying a coating liquid of a resin composition for forming a resin composition layer onto the first film, drying the coating liquid, and then covering the surface of the resin composition layer with the second film, or by applying a coating liquid of a resin composition for forming a resin composition layer onto the second film, drying the coating liquid, 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; and plastic films such as polyvinyl chloride films, polyurethane films, nylon films, polyolefin films, triacetyl cellulose films, and cycloolefin films. From the viewpoint of handling, polyester films and polyolefin films are preferred. From the viewpoint of small heat shrinkage, biaxially oriented polyester films and biaxially oriented polyolefin films are preferred, and biaxially oriented polyester films are more preferred. In addition, the first film preferably has a release layer on the surface that comes into contact with the resin composition layer, as will be described later. Examples of biaxially stretched polyester films having a release layer include the Therapeel series from Toray Advanced Film Co., Ltd., the Cosmo Peel 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] In the encapsulating sheet according to the present disclosure, the shrinkage percentage of the first film measured under the following conditions is 1.2% or less: That is, the shrinkage percentage of the first film is determined by heating the first film in an unheated state at 150°C for 120 minutes and measuring the shrinkage percentage in the longitudinal direction (MD) of the first film obtained after the heat treatment. Here, even if a film has a longitudinal shrinkage rate of more than 1.2% when heated at 150°C for 120 minutes, if the shrinkage rate can be reduced to 1.2% or less by undergoing an annealing treatment as described below, the treated film can be used as the first film. Of course, the shrinkage rate of a film having a shrinkage rate of 1.2% or less can also be reduced by annealing the film. In this specification, the MD direction refers to the machine direction in the production of film products such as the first film, and refers to the longitudinal direction of the film. On the other hand, the TD direction (transverse direction) refers to the width or horizontal direction of the film. In film products, the shrinkage rate in the MD direction of the film is usually greater than the shrinkage rate in the TD direction. In particular, biaxially stretched films are prone to thermal shrinkage in the MD direction, so the thermal shrinkage rate in the MD direction is important.

[0023] As described above, during the (b) filling step and (c) heat aging step in FIG. 2 , the first film 12 is placed on the upper side of the resin composition layer 11 (i.e., the side not in contact with the substrate 21 or the micro LED element 20). Therefore, during the (b) filling step and the (c) heat aging step, especially during the (c) heat aging step, it is important that the first film 12 not undergo thermal shrinkage as much as possible. If the first film 12 shrinks significantly during the (c) heat aging step, deformation is likely to occur at the end of the resin composition layer during curing or at the end of the encapsulating layer after curing, making the seams of the panels more noticeable when multiple display panels are joined together. Furthermore, if undulation occurs in the first film due to thermal shrinkage, the undulation is transferred to the encapsulating layer after curing, which can easily cause image distortion when the display is assembled, impairing the display's appearance.

[0024] As described above, in step (c) shown in FIG. 2 in the present 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 since thermal shrinkage in the MD direction is likely to occur particularly when a biaxially stretched film is used, the thermal shrinkage rate in the MD direction becomes important. Therefore, the first film constituting the encapsulating sheet of the present disclosure has a heat shrinkage rate of 1.2% or less in the MD direction after a heat aging process at 150°C for 2 hours (120 minutes). Using a film with a heat shrinkage rate of 1.2% or less in the MD direction as the first film can prevent excessive shrinkage of the first film during the heat aging process. This makes it difficult for deformation of the end of the resin composition layer caused by shrinkage of the first film to occur, making the seams of the panels less noticeable when multiple display panels are joined together. Furthermore, using a first film with a heat shrinkage rate of 1.2% or less in the MD direction can suppress waviness of the first film due to heat shrinkage, improving the appearance of the encapsulating layer after curing. That is, a first film with a heat shrinkage rate of 1.2% or less in the MD direction is important in terms of suppressing deformation and waviness of the end of the resin composition layer. From the same perspective, the heat shrinkage rate of the first film 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 for providing such a low-shrinkage film. In other words, the shrinkage rate of the first film can be adjusted by annealing. Although the annealing method is not particularly specified, in the case of a film-like material, examples of the annealing method include leaving the film-like material in a high-temperature environment, transporting the film-like material in a high-temperature environment, or contacting the film-like material with a high-temperature tool. By increasing the annealing temperature or lengthening the heat treatment time, the heat shrinkage rate of the film after treatment can be reduced compared to the heat shrinkage rate of the film before treatment. Thus, the first film is preferably an annealed product that has been subjected to annealing.

[0026] The annealing temperature is preferably 100° C. to 210° C. From the viewpoint of reducing the thermal shrinkage rate in the MD direction, the annealing temperature 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 the treatment, the annealing temperature is preferably 200° C. or lower, and even more preferably 190° C. or lower. The annealing time is preferably 30 seconds to 60 minutes. From the viewpoints of uniformity of the annealing and reducing the thermal shrinkage rate of the first film in the MD direction after the treatment, the annealing time is preferably 45 seconds or more, more preferably 1 minute or more, and even more preferably 2 minutes or more. From the viewpoints of shape stability and maintaining peel strength of the first film, the annealing time is preferably 50 minutes or less, more preferably 45 minutes or less, and even more preferably 30 minutes or less. From the above, the first film is more preferably an annealed biaxially oriented polyester film or 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, which is preferably formed by applying a release agent such as a silicone resin, an alkyd resin, a fluororesin, or a melamine resin to the film, and from the viewpoint of handling (prevention of separation), a release layer using a silicone resin is more preferred. Peel force P between the first film and the resin composition layer l The peeling force P of the first film is 8mN / 25mm or more. l By setting the peel strength P of the first film to 8 mN / 25 mm or more, the handling property can be improved. In addition, the occurrence of poor appearance due to marks left at the peeled portion caused by partial peeling of the resin composition layer and the first film during the heat aging step can be suppressed, and deformation of the resin composition layer can also be suppressed. l The peel strength 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 peel strength P of the first film to 150 mN / 25 mm or less, it is possible to suppress zipping when peeling the first film after the heat aging step, and to suppress defects in the appearance of the resin composition layer. l is preferably 120 mN / 25 mm or less, and more preferably 100 mN / 25 mm or less. First film peeling force P lcan 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. When it is desired to reduce the value of the release force, for example, treatments such as increasing the surface roughness or increasing the amount of release agent applied are effective, and when it is desired to increase the value of the release force, the opposite adjustment can be made. First film peeling force P l can be measured, for example, by attaching the resin composition layer of the encapsulating sheet to a SUS plate, and peeling the first film from the resin composition layer at a peel angle of 180° and a peel speed of 300 mm / min in an environment of 23°C and a relative humidity of 50%. The first film may have a functional layer in addition to the release layer, such as an antistatic layer or an antiblocking layer.

[0028] First film thickness T l The thickness T of the first film is 20 μm or more. This prevents the waviness of the first film from being transferred to the resin composition layer, and also prevents the pattern of the upper plate of the press from being transferred to the resin composition layer in the filling step, thereby making it possible to form a uniform resin composition layer. l is preferably 25 μm or more, and more preferably 35 μm or more. Also, the thickness of the first film T l The thickness T of the first film is 120 μm or less. This allows the first film to appropriately follow the deformation of the resin composition layer relative to the void during the filling step, and also controls the pressure transmission to the resin composition layer, allowing the resin composition layer to flow uniformly, resulting in good embeddability and adhesion to the adherend. l is preferably 90 μm or less, and more preferably 80 μm or less. In addition, when a release layer or a functional layer is provided on the first film, the thickness T l is a value including the release layer and the functional layer.

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

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

[0031] The value represented by the above formula (1) can be adjusted by the type and thickness of the first film. When it is desired to increase the value of formula (1), for example, it is effective to use a biaxially stretched first film or to increase the thickness of the first film, and when it is desired to decrease the value of formula (1), it is effective to use a non-stretched first film or to decrease the thickness of the first film, for example.

[0032] [Second film] The second film is not particularly limited, and examples thereof 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, triacetyl cellulose films, and cycloolefin films. From the viewpoint of handling, polyester films and polyolefin films are preferred. The second film is preferably laminated directly to the resin composition layer.

[0033] The second film preferably has a release layer on the surface facing the resin composition layer, which is preferably formed by applying a release agent such as a silicone resin, an alkyd resin, a fluororesin, or a melamine resin to the film, and from the viewpoint of handling (prevention of separation), a release layer using a silicone resin is more preferred. The peeling force P2 of the second film is preferably from 1 to 90 mN / 25 mm, more preferably from 3 to 70 mN / 25 mm, and even more preferably from 5 to 60 mN / 25 mm. The peel strength 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 reduce the peel strength, it is effective to increase the surface roughness or the amount of release agent applied. To increase the peel strength, the opposite can be done. The peel strength P2 of the second film is preferably smaller than the peel strength P1 of the first film. Specifically, the value of P1 / P2 is more preferably 1.1 to 20, and even more preferably 1.1 to 17. The peel strength 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 peel angle of 180° and a peel speed of 300 mm / min in an environment of 23°C and a relative humidity of 50%. The second film may have a functional layer in addition to the release layer, such as an antistatic layer, an antiblocking layer, or a roughness-forming layer. The thickness T2 of the second film is not particularly limited, but from the viewpoint of handling, it is preferably 12 to 188 μm, more preferably 12 to 100 μm, and even more preferably 20 to 60 μm. When a release layer or a functional layer is provided on the second film, the thickness T2 is a value including the thickness of the release layer and the functional layer.

[0034] [Resin composition layer] The resin composition layer contains at least a resin component, i.e., a resin (A), and may contain at least one of a polymerization initiator (B), an inorganic filler (P), a colorant (Q), and a crosslinking agent (E), and may further contain other components. Various optical properties are required for the resin composition layer depending on the application. For example, in applications requiring high transparency, high transparency can be achieved by not using a colorant. In applications requiring light-blocking properties, light-blocking properties can be imparted by using a black colorant. In applications requiring reflectivity, reflectivity can be imparted by using a white colorant. In applications requiring a high refractive index, the refractive index can be increased by using an inorganic filler (P) with a high refractive index. In the present disclosure, the resin (A) is a substance that functions as a binder to bond and fix objects together, specifically to a substrate having a micro LED thereon or to fix the micro LED thereon.

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

[0036] The resin composition layer of the present disclosure preferably has a glass transition temperature (Tg) of 20°C or higher, as determined by dynamic viscoelasticity measurement in a torsion mode at a frequency of 1 Hz, and a loss tangent (tanδ) at 100°C. 100) is preferably 0.2 or more. By having a Tg of 20° C. or higher, the blocking suppression and prevention properties in the step (a) shown in FIG. 2 are further improved. 100 When tan δ is 0.2 or more, the resin composition layer 11 becomes more easily deformable and flowable in the step (b) shown in FIG. 2, and the ability to suppress and prevent air entrapment is further improved. 100 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 When tan δ is 0.2 or more, the pressure applied to the resin composition layer 11 in the filling step can be more easily diffused, and not only can the air entrapment be suppressed and prevented, but also the embeddability, smoothness, and adhesion to the adherend, which will be described later, can be further improved. 100 By making the ratio 2.5 or less, excessive deformation and flow of the resin composition layer during the filling step can be easily suppressed, and a sufficient thickness of the resin composition layer can be easily ensured even in the peripheral part of the micro LED. The above-mentioned Tg and tanδ 100 is determined by dynamic viscoelasticity measurement in torsion mode at a frequency of 1 Hz and from -50 to 150°C. tanδ is the ratio of loss modulus to storage modulus, and Tg is the temperature at the peak top of tanδ. 100 is the ratio of loss modulus to storage modulus at 100°C.

[0037] Furthermore, the resin composition layer of the present disclosure has a loss modulus (G'') at 100°C obtained by dynamic viscoelasticity measurement in a torsion mode at a frequency of 1 Hz. 100 ) but 5×10 3Pa ~2×10 7 Preferably, it is 1×10 4 Pa~9×10 6 Pa is more preferable, and 2×10 4 Pa~5×10 5 Pa is more preferred. G'' 100However, when the thickness is within the above range, the resin composition layer is considered to be able to deform and flow well during the filling step, and to have improved embeddability, smoothness, and adhesion to the adherend. 100 is 2 x 10 7 By ensuring that the pressure is G'' or less, the resin composition layer can be easily deformed and flowed without dissipating energy during the filling step, and the ability to fill recesses is improved. 100 is 5 x 10 3 By ensuring that the pressure is equal to or higher than Pa, energy is dissipated during the filling process, which makes it possible to suppress excessive deformation and flow of the resin composition layer, and ensures a sufficient thickness of the resin composition layer even in the peripheral part of the micro LED. Tg and tanδ 100 and G'' 100 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 the type and content of the crosslinking agent (E) and monomer, which are other components.

[0038] The dynamic viscoelasticity is preferably measured for a resin composition layer laminated to a thickness of 500 μm or more, as described in the Examples below, by preparing two sets of encapsulating sheets, bonding the resin composition layers together using a laminator at 90°C to produce a first film / resin composition layer / first film laminate, and then peeling off the first film from one side of the laminate and repeatedly bonding the resin composition layers of the encapsulating sheets together to a thickness of 500 μm or more, and then measuring the dynamic viscoelasticity. Alternatively, two sets of encapsulating sheets without a first film can be prepared, and similarly, resin composition layers having a thickness of 500 μm or more can be formed.

[0039] Resin composition layer thickness T a From the viewpoint of embedding properties, the thickness is preferably 1 to 100 μm, more preferably 2 to 60 μm, further preferably 5 to 50 μm, and particularly preferably 10 to 40 μm. Resin composition layer thickness T aBy setting the thickness within the above range, the pressure applied to the resin composition layer in the filling step is appropriately dispersed and sufficiently uniformed, thereby further improving embeddability. The resin composition layer may be in the form of a single layer or a laminate of two or more layers, and in the case of two or more layers, the thickness refers to the total thickness. Resin composition layer thickness T a can be adjusted by the method for forming the resin composition layer described below. The thickness T a is measured by the method described in the Examples below.

[0040] Resin composition layer thickness T a is the ratio to the thickness T1 of the first film described later, expressed as 0.1≦T a It is preferable that / T1≦3 is satisfied, and 0.2≦T a It is more preferable that / T1≦1.5 is satisfied, and 0.2≦T a It is more preferable that / T1≦1.2 be satisfied. By setting the thickness within the above range, the pressure transmission applied to the resin composition layer in the filling step described below can be controlled, and the resin composition layer can flow uniformly, resulting in better embeddability.

[0041] The resin composition for forming the 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), and a solvent (a dispersion medium for the filler (P) and the colorant (Q), or simply referred to as a solvent). The optional solvent can be used to adjust the viscosity and other coating properties when mixing the components constituting the resin composition layer. For example, ester-based, ether ester-based, ether-based, alcohol-based, aromatic-based, or other solvents compatible with the resin (A) can be used as appropriate. Specific examples of suitable solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, cyclohexanone, toluene, xylene, isopropyl alcohol, and N-methyl-2-pyrrolidone. For stirring, a known stirring device can be used, and a disper, mixer, shaker, homogenizer, etc. are preferred. The resin composition not containing the inorganic filler (P) and the colorant (Q) may be produced in two or more steps, firstly by mixing the resin (A) and an optional solvent to prepare a mixture, and secondly by adding the remaining resin (A), the polymerization initiator (B), and other components as necessary. The resin composition containing either the inorganic filler (P) or the colorant (Q) may be produced in two or more steps, firstly by dispersing the inorganic filler (P) or the colorant (Q) in a solvent to obtain a dispersion, and secondly by adding the resin (A), the polymerization initiator (B), and other components as necessary. The resin (A) and / or the dispersant may also be used to obtain the dispersion.

[0042] Resin (A) The resin (A) is preferably a resin having a weight-average molecular weight (Mw) of 10,000 or more. By including a resin (A) having an Mw of 10,000 or more, the film-forming properties of the resin composition layer can be further improved. 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 the 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 the resin (A) is more preferably 10,000, even more preferably 20,000, and particularly preferably 30,000. The weight-average molecular weight (Mw) is a polystyrene-equivalent 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] The resin (A) can be used alone or in combination of two or more. The content of the resin (A) is preferably 10 to 99 mass%, more preferably 25 to 95 mass%, and even more preferably 60 to 90 mass%, based on the total amount (100 mass%) of the resin composition layer. When two or more types of resin (A) are contained, the content of each resin (A) is preferably 5 mass% or more, and the total content is preferably within the above range. By setting the content of resin (A) within the above range, when either inorganic filler (P) or colorant (Q) is contained, compatibility with the inorganic filler (P) and colorant (Q) is improved, and optical properties are improved.

[0044] Suitable examples of the resin (A) include (meth)acrylic resin (a1), urethane resin (a2) such as polyurethane resin or polyurethane urea resin, epoxy resin (a3), maleic acid resin, styrene-maleic acid copolymer, polystyrene resin, polybutadiene resin, polyester resin, condensation polyester resin, addition 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, cyclized rubber resin, cellulose, polyethylene (HDPE, LDPE), etc. From the viewpoint of embeddability, it is preferable that the resin (A) contains 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 that the resin composition layer contains a (meth)acrylic resin (a1).From the viewpoint of storage stability, it is particularly preferable that the resin composition layer contains 50% or more of the (meth)acrylic resin when the solid content of the resin composition layer is taken as 100% by mass.

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

[0046] [(Meth)acrylic resin (a1)] In the present disclosure, the (meth)acrylic resin (a1) is a (meth)acrylic copolymer obtained by copolymerizing a (meth)acrylic acid ester monomer, and is a polymer having structural units based on 2 to 20,000 monomers. A suitable example of the (meth)acrylic acid ester monomer is a (meth)acrylic acid alkyl ester monomer. When a functional group that can be used in polymerization / crosslinking reactions is introduced, a (meth)acrylic copolymer obtained by copolymerizing a functional group-containing monomer and a (meth)acrylic acid ester monomer is preferred. The (meth)acrylic resin (a1) of the present 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 here refers to the portion where the carbon-carbon double bond of the (meth)acrylic acid ester monomer is cleaved and polymerized repeatedly to form a continuous elongated bond.

[0047] The (meth)acrylic acid alkyl ester monomer is a compound obtained by esterifying (meth)acrylic acid to introduce an alkyl group or a cycloalkyl group, and the alkyl group or the cycloalkyl group may be any of a linear, branched, or cyclic saturated aliphatic hydrocarbon group. The saturated aliphatic hydrocarbon group is preferably a saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms, and more preferably a saturated aliphatic hydrocarbon group having 1 to 12 carbon atoms. 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. 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, and isobornyl (meth)acrylate. Among these, from the viewpoint of dispersibility of the inorganic filler (P) and the colorant (Q), it is particularly preferable to use methyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate, and it is most preferable to use methyl (meth)acrylate and n-butyl (meth)acrylate.

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

[0049] The (meth)acrylic resin (a1) preferably has a structural unit derived from a functional group-containing monomer and / or an unsaturated bond. Examples of functional group-containing monomers include carboxy group-containing monomers, hydroxy group-containing monomers, epoxy group-containing monomers, and amino group-containing monomers. By including a functional group-containing monomer, the cohesive strength of the resin (A) is improved, and a tough resin composition layer is obtained. In particular, it is preferable to include a carboxy group-containing monomer, a hydroxy group-containing monomer, or an epoxy group-containing monomer.

[0050] Examples of the carboxyl group-containing monomer 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, from the viewpoint of adhesion, 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate are more preferred.

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

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

[0054] The (meth)acrylic resin (a1) preferably contains structural units derived from functional group-containing monomers in a total amount of 0.1 to 20 mass % relative to 100 mass % of the monomers constituting the (meth)acrylic resin (a1). By adjusting the amount within this range, the adhesive strength can be adjusted. It is preferable that the content of structural units derived from carboxyl group-containing monomers is 0.1 to 10% by mass. By containing the structural units in this range, adhesion can be further improved. It is preferable that the content of structural units derived from hydroxyl group-containing monomers is 0.1 to 10% by mass. When the content is within this range, adhesion can be further improved.

[0055] For the purpose of introducing an unsaturated bond into the (meth)acrylic resin (a1), a monomer having an epoxy group or a monomer having an isocyanate group can be used. The (meth)acrylic resin (a1) having an unsaturated bond can be obtained by the following two-step reaction. First, a (meth)acrylic copolymer having a carboxyl group is obtained using a monomer having a carboxyl group such as (meth)acrylic acid, or a monomer having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate is used to obtain a (meth)acrylic copolymer having a hydroxyl group. Next, at least a portion (10 to 100 mol%) of the carboxyl groups or hydroxyl groups of the (meth)acrylic copolymer is preferably reacted with an epoxy group or an isocyanate group in a monomer having an unsaturated bond such as an epoxy group or an isocyanate group and a (meth)acryloyl group to introduce an unsaturated bond such as a (meth)acryloyl group into the (meth)acrylic resin (a1). Note that, in the sense of modifying the (meth)acrylic copolymer, a monomer having an epoxy group or an isocyanate group and an unsaturated bond such as a (meth)acryloyl group is sometimes referred to as a modifier. There is no limitation on the amount of unsaturated bonds such as (meth)acryloyl groups introduced. The (meth)acrylic resin (a1) may 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. The number of epoxy groups in the monomer having an epoxy group and an unsaturated bond such as a (meth)acryloyl group is preferably one or less per molecule. 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 other monomers copolymerizable with (meth)acrylic acid alkyl esters and functional group-containing monomers. Examples include monomers having an alkyleneoxy group and other vinyl monomers. Examples include methoxyethyl acrylate, methoxydiethylene glycol acrylate, vinyl acetate, vinyl crotonate, styrene, acrylonitrile, and acrylamide. The structural units derived from the other monomers preferably account for 0.1 to 20% by mass of 100% by mass of the monomers constituting the (meth)acrylic resin (a1).

[0058] The (meth)acrylic resin (a1) can be obtained by polymerizing the aforementioned (meth)acrylic monomer mixture. During polymerization, a polymerization initiator can be used, if necessary. The amount of the 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 performed by solution polymerization, bulk polymerization, emulsion polymerization, or suspension polymerization, with solution polymerization being most preferred due to 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 approximately 2 to 12 hours.

[0059] The polymerization initiator is preferably a radical polymerization initiator. Suitable radical polymerization initiators are peroxides and azo compounds. Any of the thermal radical polymerization initiators described below can be used, and specifically, 2,2'-azobisisobutyronitrile (abbreviation: AIBN) is preferred.

[0060] [Urethane resin (a2)] In the present disclosure, the 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 the main chain. The main chain here refers to the portion where the bond sites that are extended by reacting a polyisocyanate with a polyol are continuous. The polyisocyanate may be any polyisocyanate having two or more isocyanate groups per molecule. From the viewpoint of dispersibility of the inorganic filler (P) and colorant (Q), diisocyanates or triisocyanates are preferred, with diisocyanates being more preferred. The diisocyanate may be appropriately selected from known aliphatic diisocyanates such as hexamethylene diisocyanate and known aromatic diisocyanates such as benzene-1,3-diisocyanate. Furthermore, 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 may be any polyol having two or more hydroxyl groups per molecule. From the viewpoint of dispersibility of the inorganic filler (P) and colorant (Q), a diol or triol is preferred, and a diol is more preferred. The diol may be appropriately selected from known aliphatic diols such as ethylene glycol and known aromatic diols such as benzenediol. Prepolymers such as polyether polyols, polyester polyols, and polycarbonate polyols may also be used.

[0061] The urethane resin (a2) may be a polyurethane urea resin further having a urea bond. The polyurethane urea resin can be synthesized, for example, by reacting a urethane resin having an isocyanate group at its terminal with a polyamine. The polyamine may be any polyamine having two or more amino groups in one molecule, and is preferably a diamine or triamine, more preferably a diamine, from the viewpoint of dispersibility of the inorganic filler (P) and the colorant (Q). The diamine may be appropriately selected from known aliphatic diamines such as ethylenediamine and known aromatic diamines such as phenylenediamine.

[0062] From the viewpoint of dispersibility of the inorganic filler (P) and the colorant (Q), the urethane resin (a2) preferably further has a radically polymerizable functional group such as a (meth)acryloyl group, an N-vinyl group, a vinyl ether group, an allyl group, an unsaturated carboxylic acid group, etc. as a functional group, and more preferably has a (meth)acryloyl group. Specifically, the (meth)acryloyl group can be introduced by addition reaction of the above-mentioned polyol, diisocyanate, or triisocyanate with an acrylate having a hydroxyl group.

[0063] [Epoxy resin (a3)] In the present disclosure, the epoxy resin (a3) ​​is a resin having two or more epoxy groups per molecule and a weight-average molecular weight (Mw) of 10,000 or more. The epoxy resin (a3) ​​also includes compounds having a functional group added thereto. The functional group preferably includes a radically polymerizable functional group such as a (meth)acryloyl group, an N-vinyl group, a vinyl ether group, an allyl group, or an unsaturated carboxylic acid group, and more preferably includes a (meth)acryloyl group. Regarding the properties of the epoxy resin (a3), the use of a liquid form can improve adhesion, while the use of a solid form can improve film-forming properties of the resin composition layer. Preferred examples of the epoxy resin (a3) ​​include glycidyl ether type epoxy resins, glycidylamine type epoxy resins, glycidyl ester type epoxy resins, alicyclic (cycloaliphatic) epoxy resins, bisphenol type epoxy resins, hydrogenated bisphenol type epoxy resins, etc. 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 the glycidylamine type epoxy resin include tetraglycidyldiaminodiphenylmethane and tetraglycidylmetaxylylenediamine. Examples of the glycidyl ester type epoxy resin include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate. Examples of cyclic aliphatic (alicyclic) epoxy resins include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate, bis(epoxycyclohexyl)adipate, and the like. Examples of bisphenol-type epoxy resins include bisphenol A-type epoxy resins, bisphenol F-type epoxy crosslinkers, bisphenol S-type epoxy resins, bisphenol AD-type epoxy resins, etc. Bisphenol A-type epoxy resins are particularly preferred from the viewpoint of adhesion. Examples of hydrogenated bisphenol epoxy resins include hydrogenated bisphenol A epoxy resins, hydrogenated bisphenol F epoxy resins, etc. In particular, hydrogenated bisphenol A epoxy resins are 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, and it is preferable to use a thermal polymerization initiator from the viewpoint of film-forming property and adhesion of the resin composition layer. When either a thermal polymerization initiator or a photopolymerization initiator is used, it is preferable that the resin (A) has one or more radically polymerizable functional groups per molecule as functional groups. Examples of the radically polymerizable functional group include a (meth)acryloyl group, an N-vinyl group, a vinyl ether group, an allyl group, etc., and a (meth)acryloyl group is preferred.

[0066] In the present embodiment, a thermal radical polymerization initiator or a thermal cationic polymerization initiator can be used as the thermal polymerization initiator. From the viewpoint of storage stability of the resin composition layer, a thermal radical polymerization initiator is preferred. The thermal radical polymerization initiator has a function of generating radicals by heat, and examples of the thermal radical polymerization initiator include organic peroxide polymerization initiators and azo thermal polymerization initiators.

[0067] From the viewpoint of storage stability, an azo thermal polymerization initiator is preferably used. From the viewpoint of suppressing foaming during curing and improving the appearance after curing, an organic peroxide polymerization initiator is preferably used. A thermal radical polymerization initiator adjusts the shrinkage force during thermal curing, and provides favorable sealing properties and low-temperature curing properties. In particular, when a thermal radical polymerization initiator is used, from the viewpoint of storage stability and reaction stability, it is preferable that the 10-hour half-life temperature is 60°C or higher and 170°C or lower.

[0068] Examples of organic peroxide polymerization initiators having a 10-hour half-life temperature of 60°C or higher and 170°C or lower 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)hexyne-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)butylpentanoate; 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 disuccinic acid peroxide (66°C); Examples of peroxycarbonates include, but are not limited to, t-butylperoxyisopropyl carbonate (99°C), t-amylperoxyisopropyl carbonate (96°C), t-hexylperoxyisopropyl carbonate (95°C), t-butylperoxy-2-ethylhexyl carbonate (99°C), and t-amylperoxy-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 having a 10-hour half-life temperature of 60°C or higher and 170°C or lower include 2,2'-azobisbutyronitriles such as 2,2'-azobisisobutyronitrile (65°C) and 2,2'-azobis(2-methylbutyronitrile) (68°C); 1,1'-azobis-1-alkanenitriles such as 1,1'-azobis(cyclohexane-1-carbonitrile) (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'-azobisisobutyrate, and 1,1'-azobis(acetoxy-1-phenylethane). Examples of azo compounds having a carboxyl group or a hydroxyl group 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. By containing the thermal radical polymerization initiator in an amount of 0.01 to 20% by mass, the transparency of the cured product of the resin composition layer can be improved in transparent applications. Furthermore, by containing the thermal radical polymerization initiator in an amount of 0.01% by mass or more, low-temperature curing properties and handling properties can be improved, and by containing the thermal radical polymerization initiator in an amount of 20% by mass or less, storage stability can be improved. For the same reasons as above, the amount of the peroxide-based thermal radical polymerization initiator is preferably 0.01 to 20 mass %, more preferably 0.1 to 18 mass %, even more preferably 0.8 to 16 mass %, even more preferably 1 to 13 mass %, and particularly preferably 4.4 to 13 mass %, of the total solid content of the resin composition layer.

[0071] From the viewpoint of storage stability, it is preferable not to use a thermal radical polymerization initiator in combination with a photoradical polymerization initiator.

[0072] Examples of the photopolymerization initiator include triazine-based photopolymerization initiators, borate-based photopolymerization initiators, carbazole-based photopolymerization initiators, acetophenone-based photopolymerization initiators, and oxime ester-based photopolymerization initiators. The acetophenone-based photopolymerization initiators and oxime ester-based photopolymerization initiators are preferred because they are less likely to yellow during the heat aging process. From the viewpoint of preventing yellowing, the content of the photopolymerization initiator is preferably 0.5 to 10 mass %, and more preferably 0.5 to 5 mass %, based on the total amount (100 mass %) of the resin composition layer.

[0073] Colorant (Q) When the purpose is to form a reflective layer, for example, titanium oxide, zinc oxide, lithopone, etc. can be used as the colorant (Q). From the viewpoint of whiteness, a white pigment is preferred, and among them, titanium oxide is preferred from the viewpoint of dispersibility. By using a white pigment to make the resin composition layer white and sealing the spaces between and 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] As the titanium oxide used in the present disclosure, known titanium oxides such as rutile titanium oxide and anatase titanium oxide can be used. From the viewpoint of deterioration of resins due to light, rutile titanium oxide is preferred. Specific examples of rutile titanium dioxide include "Tipake 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" manufactured by Ishihara Sangyo Kaisha, Ltd., "Tipure R-101, R-103, R-104, R-105, R-108, R-900, R-902+, R-960, R-706" manufactured by DuPont, and "TITONE" manufactured by 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, and D-918.

[0075] The arithmetic mean particle diameter of the rutile-type titanium oxide is preferably 0.1 to 1.5 μm, and more preferably 0.15 to 1.1 μm. By setting the arithmetic mean particle diameter to 0.1 μm or more, it is easy to prevent aggregation and sedimentation of titanium oxide in the coating liquid for the resin composition layer. Furthermore, by setting the arithmetic mean particle diameter to 1.5 μm or less, whiteness is improved and high reflectivity is achieved. When the particle shape of the colorant (Q) has an average aspect ratio (major axis length / minor axis length) of 1.5 or more, the arithmetic mean particle diameter is determined by averaging the major axis lengths. The arithmetic mean particle diameter of the colorant (P) can be determined from the average value of approximately 20 primary particles observed in an image magnified approximately 50,000 to 1,000,000 times using a transmission electron microscope (TEM).

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

[0077] When the purpose is to form a light-shielding layer, it is preferable to use a black colorant (pigment, dye, etc.) as the colorant (Q). Specific 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 complexes, anthraquinone-based colorants, zirconium nitride, etc. A single black colorant may be used, or two or more types may be used. Furthermore, a colorant that functions as a black colorant may be used by combining colorants 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. Carbon black generally used in black colorants can be used. One or more types of known carbon black, such as channel black, furnace black, thermal black, lamp black, and acetylene black, can be used as the carbon black. Resin-coated carbon black may also be used. Carbon nanofibers and carbon nanotubes may also be used. When carbon black is blended into the resin composition layer, carbon black powder or a carbon black dispersion may be added. From the viewpoint of light-shielding properties, the average particle size of carbon black is preferably 10 nm to 500 nm, more preferably 10 nm to 300 nm, and even more preferably 10 nm to 100 nm, where the average particle size is the arithmetic mean primary particle size determined by observation with an electron microscope. From the viewpoint of dispersibility, the carbon black preferably has a specific surface area measured by the BET method of 50 to 400 m / g, a volatile content of 0.1 to 10% by weight, and a pH value of 2 to 10, more preferably a pH value of 3 to 8, and even more preferably a pH value of 3 to 6.

[0079] The amount of colorant (Q) is preferably 0.1% by mass or more, based on 100% by mass of the total solid content of the resin composition layer, from the viewpoint of exhibiting the properties of the colorant (Q). The lower limit of the amount of colorant (Q) 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) is, for example, 80% by mass or 40% by mass. From the viewpoint of obtaining a resin composition layer with good light-blocking properties, sealing properties, and handleability, 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 an inorganic filler (P) other than those described above (hereinafter simply referred to as inorganic filler (P)). Examples of such inorganic fillers (P) include inorganic compounds such as silica (e.g., 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, montmorillonite, bentonite, magnesium carbonate base, boron nitride, aluminum nitride, and titanium nitride. Metal powders such as copper, tin, zinc, nickel, silver, palladium, aluminum, iron, cobalt, gold, and platinum are also included. Preferably, the inorganic filler (P) is a spherical particle. Among these, silica is preferred, as it suppresses cure shrinkage of the cured product of the 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 resin composition layer have a total light transmittance of 70% or more in the visible light band (380 to 780 nm) and a refractive index of 1.47 to 1.56. The total light transmittance is more preferably 80% or more, even more preferably 85% or more, even more preferably 90% or more, and particularly preferably 92% or more. The lower limit of the refractive index is more preferably 1.49, even more preferably 1.51. The upper limit of the refractive index is more preferably 1.54, even more preferably 1.53. In order to adjust the refractive index, an inorganic filler (P) such as alumina, titanium oxide, or zirconium oxide may be added. The total light transmittance is the ratio of the total amount of transmitted light that passes through the cured layer to the total amount of light that enters the cured layer obtained by heat-treating the resin composition layer at 130°C for 120 minutes.

[0081] From the viewpoint of dispersibility, inorganic filler (P) should have a specific surface area of ​​5 to 400 m2 as measured by the BET method. 2 / g, and 10 to 150m 2 / g is more preferable, and 20 to 90m 2 / g is more preferred. The average primary particle diameter (hereinafter referred to as particle diameter) of the inorganic filler (P) is preferably 1 to 1200 nm. By making the particle diameter 1 nm or more, it is easy to maintain the viscosity of the resin composition at a level suitable for coating. Furthermore, by making the particle diameter 1200 nm or less, the coating film resistance is improved. The particle diameter of the inorganic filler (P) is more preferably 5 to 1000 nm, even more preferably 10 to 700 nm, and particularly preferably 50 to 300 nm. The particle diameter of the inorganic filler (P) can be determined from the average value of approximately 20 primary particles observed in an image magnified approximately 50,000 to 1,000,000 times using a transmission electron microscope (TEM). When the particle shape of the inorganic filler (P) has an average aspect ratio (major axis length / minor axis length) of 1.5 or more, the particle diameter is determined by averaging the major axis lengths.

[0082] From the viewpoint of embeddability, the content of the inorganic filler (P) (total content when two or more types are included) is preferably 0.01 to 40 mass %, more preferably 0.1 to 30 mass %, and even more preferably 0.5 to 20 mass %, based on the total amount of solids in the resin composition layer. By including 0.01 to 40 mass % of the inorganic filler (P), the effect of increasing the fluidity of the resin composition layer during the filling step is easily exhibited, and embeddability is improved.

[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 filler contains an organic acid. The filler may be subjected to a surface treatment that does not introduce an organic group, such as an alumina treatment. The surface treatment method for the inorganic filler (P) is not particularly limited, and any known or commonly used method may be used, and 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 filler (P) and colorant (Q)] It is preferable to disperse the colorant (Q) and inorganic filler (P) in the resin (A) and use them as a dispersion, from the viewpoint of adjusting the film-forming properties and reflectivity of the resin composition layer. The dispersing machine used for mechanical crushing in the dispersion process may be any commonly used dispersing machine, such as a ball mill, roll mill, sand mill, bead mill, and Nanomizer. Among these, a bead mill is preferably used. Examples of such machines include a Super Mill, a sand grinder, an agitator mill, a grain mill, a Dyno Mill, a pearl mill, and a Cobol Mill (all trade names).

[0085] In the present 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 the inorganic filler (P). In the present disclosure, the dispersant has the function of imparting repulsive force between particles so that the particles divided through the above-mentioned dispersion treatment do not re-aggregate. As the dispersant, a conventionally known compound can be used, and examples thereof include cationic, anionic, or nonionic surfactants, cationic, anionic, or nonionic polymer dispersants, and pigment derivative dispersants. From the viewpoint of storage stability of the dispersion, pigment derivative dispersants are preferred.

[0086] Pigment derivative dispersants are compounds that contain acidic, basic, or neutral groups in the organic pigment residue. Examples include compounds with acidic substituents such as sulfo, carboxyl, or phosphate groups, as well as amine salts of these, compounds with basic substituents such as sulfonamide, amide, or terminal tertiary amino groups, and compounds with neutral substituents such as phenyl or phthalimidoalkyl groups. Examples of organic pigments include phthalocyanine pigments, diketopyrrolopyrrole pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, perinone pigments, perylene pigments, thiazine indigo pigments, triazine pigments, benzimidazolone pigments, indole pigments such as benzoisoindole, isoindoline pigments, isoindolinone pigments, quinophthalone pigments, naphthol pigments, threne pigments, metal complex pigments, and azo pigments such as azo, disazo, and polyazo. By using these pigment dispersants, it becomes possible to prevent the colorant (Q) and inorganic filler (P) contained in the resin composition layer from aggregating over time, and to maintain good coating stability.

[0087] When the resin composition layer contains a white colorant, the content of the dispersant (the total content when two or more types are contained) is preferably 0.01 to 35 mass %, and more preferably 0.1 to 20 mass %, based on the total amount (100 mass %) of the resin composition layer. When the dispersant content is 0.01 mass % or more, light reflectivity is improved, and when the dispersant content is 35 mass % or less, the viscosity of the white resin composition for forming the resin composition layer falls within a suitable range, improving coatability. When the resin composition layer contains a black colorant, the content of the pigment dispersant (total content when two or more types are contained) is preferably 0.01 to 30 mass %, and more preferably 0.1 to 20 mass %, based on the total amount (100 mass %) of the resin composition layer. When the pigment dispersant is contained in an amount of 0.01 mass % or more, good light-blocking properties are achieved, and when the content is 30 mass % or less, the viscosity of the black resin composition for forming the resin composition layer falls within a suitable range, resulting in good coating suitability. When the resin composition layer contains an inorganic filler (P), the content of the dispersant is preferably 0.01 to 45 mass %, more preferably 0.1 to 35 mass %, and more preferably 1 to 30 mass %, based on the total amount of solids in the resin composition layer. When the dispersant content is 0.01 mass % or more, the brightness of the optical semiconductor element improves, and when the dispersant content is 45 mass % or less, the viscosity of the dispersion falls within a suitable range, resulting in good coating suitability.

[0088] [Crosslinker (E)] The resin composition layer of the present disclosure may contain a crosslinking agent (E). The crosslinking agent (E) crosslinks with the reactive functional groups of the resin (A) during the heat pressing or heat aging in the filling step, thereby increasing the cohesive force of the resin composition layer and improving adhesion. The crosslinking agent (E) has a plurality of functional groups that can react with the functional groups of the resin (A). Examples of the crosslinking agent (E) include known compounds such as acid anhydride group-containing compounds, imidazole compounds, isocyanate compounds, aziridine compounds, amine compounds, and compounds having an epoxy group. The loss tangent (tanδ) of the resin composition layer is 100 From the viewpoint of adjusting the amount of the copolymer, an isocyanate compound, a compound having an epoxy group, an aziridine compound, or an imidazole compound is preferred.

[0089] The isocyanate compound is an isocyanate having two or more isocyanate groups. When the resin (A) has a hydroxyl group or an amino group, it can react with the isocyanate group. The isocyanate compound is preferably, for example, an isocyanate monomer such as an aromatic polyisocyanate, an aliphatic polyisocyanate, an araliphatic polyisocyanate, or an alicyclic polyisocyanate, as well as a biuret, a nurate, or an adduct thereof. The isocyanate compound is preferably a trifunctional isocyanate compound from the viewpoint of forming a sufficient crosslinked structure, and more preferably an adduct or nurate, which is a reaction product of an isocyanate monomer and a trifunctional low-molecular-weight active hydrogen-containing compound. Examples of the adducts include a trimethylolpropane adduct of hexamethylene diisocyanate, a trimethylolpropane adduct of tolylene diisocyanate, and a trimethylolpropane adduct of isophorone diisocyanate. Examples of the nurates include a nurate of hexamethylene diisocyanate, a nurate of tolylene diisocyanate, and a nurate of isophorone diisocyanate, with a trimethylolpropane adduct of hexamethylene diisocyanate, a trimethylolpropane adduct of tolylene diisocyanate, and a trimethylolpropane adduct of isophorone diisocyanate being more preferred.

[0090] When the resin (A) has a carboxy 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 examples of the compound having an epoxy group include glycidyl ether-type epoxy compounds, glycidyl amine-type epoxy compounds, glycidyl ester-type epoxy compounds, and cycloaliphatic (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, tetrabromobisphenol A type epoxy compounds, brominated phenol novolac type epoxy compounds, tris(glycidyloxyphenyl)methane, and tetrakis(glycidyloxyphenyl)ethane.

[0092] Examples of the glycidylamine type epoxy compound include tetraglycidyldiaminodiphenylmethane, triglycidyl paraaminophenol, triglycidyl meta-aminophenol, and tetraglycidyl meta-xylylenediamine.

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

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

[0095] Examples of the aziridine compound include trimethylolpropane tris[3-(aziridin-1-yl)propionate], tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, 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 the imidazole compounds include 2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole, as well as compounds with improved storage stability, such as imidazole compounds encapsulated in microcapsules.

[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 content within the above range, adhesion can be suitably adjusted.

[0098] [Other ingredients] The resin composition layer of the present disclosure may contain other components as long as they do not impair the objectives of the present disclosure. For example, silane coupling agents, surface conditioning additives, curing accelerators, curing retarders, softeners, antistatic agents, lubricants, antiblocking agents, adhesion improvers, etc. may be added. It is preferable to include a silane coupling agent in order to improve adhesion to the glass substrate on which the micro LED is mounted. Furthermore, when the resin (A) has a polymerizable unsaturated bond, it may contain a monomer that contributes to the formation of the resin composition layer.

[0099] A silane coupling agent is a compound in which a hydrolyzable group such as a methoxy group or an ethoxy group and a functional group such as an epoxy group are bonded to a silicon atom via an alkylene group. Examples of silane coupling agents include: alkoxysilane compounds having a (meth)acryloxy group, such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyltripropoxysilane, 3-(meth)acryloxypropyltributoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, and 3-(meth)acryloxypropylmethyldiethoxysilane; Alkoxysilane compounds having a vinyl group, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane, and vinylmethyldiethoxysilane; alkoxysilane compounds having an amino group, such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltripropoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, 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-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, hexamethyldisilazane, and silicone resins having alkoxysilyl groups in the molecule. From the viewpoint of adhesion, an alkoxysilane compound is preferred, and 3-glycidoxypropyltrimethoxysilane is more preferred. When a resin (A) having a polymerizable unsaturated bond is used, an alkoxysilane compound having a (meth)acryloxy group is preferably used.

[0100] The curing accelerator may be contained to adjust the crosslinking rate of the resin composition layer of the present disclosure. The curing accelerator is not particularly limited and can be selected appropriately. Specific examples of the curing accelerator include amine-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators.

[0101] As described above, the sealing sheet of the present disclosure includes a first film and a resin composition layer for forming a sealing layer that is laminated directly on the first film, and can be obtained by applying a coating liquid of a resin composition for forming the resin composition layer onto the first film and drying it. Furthermore, when a three-layer structure is formed by laminating a first film, a resin composition layer for forming a sealing layer laminated directly on the first film, and a second film in this order, the structure can be obtained by applying a coating liquid of a resin composition for forming a resin composition layer onto the first film, drying the coating liquid, and then covering the surface of the resin composition layer with the second film, or by applying a coating liquid of a resin composition for forming a resin composition layer onto the second film, drying the coating liquid, and then covering the surface of the resin composition layer with the first film.

[0102] In industrial production, a sealing sheet is often formed by unwinding a long first film wound into a roll, coating a coating liquid of a resin composition for forming a resin composition layer onto the unwound first film, and drying the coating liquid. Alternatively, a sealing sheet is often formed by unwinding a long second film wound into a roll, coating a coating liquid of a resin composition for forming a resin composition layer onto the unwound second film, drying the coating liquid, and unwounding the long first film wound into a roll, covering the surface of the resin composition layer for forming the sealing layer with the unwound first film. Therefore, in the encapsulating sheet, the MD direction of the resin composition layer for forming the encapsulating layer coincides with the MD direction of the first film.

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

[0104] Hereinafter, the present disclosure will be specifically described with reference to examples and comparative examples, but the present disclosure is not particularly limited to the examples. In the following description, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified. The following Examples 7, 16 and 23 are for reference only.

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

[0106] [180℃ annealing] Each of the films (F-1) to (F-9) in the form of a roll of 500 mm in the TD direction was subjected to an annealing treatment using a winding-type film annealing device (manufactured by Shinko Seiki Co., Ltd.). Specifically, each of the films (F-1) to (F-9) was unwound and transported at a transport speed of 5 m / min through a hot air heating furnace set at a heating temperature of 180°C. After transport, the film was slit 100 mm to the left and right from the end in the TD direction, and the center portion was wound up to obtain first films (F-101) to (F-109). [110℃ annealing] First films (F-301) to (F-309) annealed at 110°C were produced by treating them in the same manner as the 180°C annealing treatment, except that the heating temperature was changed to 110°C.

[0107] [Table 1]

[0108] [Production of first film, etc. 2] [Preparation of peelable film] 100 parts by mass of methylvinylpolysiloxane with both molecular chain terminals capped with dimethylvinylsiloxy groups, 5.2 parts by mass of methylvinylpolysiloxane with one branched chain and three molecular chain terminals capped with dimethylvinylsiloxy groups, 3.7 parts by mass of methylhydrogenpolysiloxane with 12 branched chains and both molecular chain terminals capped with trimethylsiloxy groups, 0.1 parts by mass of 1-ethynylcyclohexanol, and 1.0 part by mass of phenyl-containing organopolysiloxane were added and stirred until sufficiently uniform. Then, a platinum catalyst was added so that the platinum content was 50 ppm relative to the total solids content, to produce a release agent.

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

[0110] [Production of first film, etc. 3] (F-1) Instead of Cerapeel BX9A-50μm (product name, manufactured by Toray Industries, Inc.), (F-11) Pylen Film OT P2161-50μm (product name, manufactured by Toyobo Co., Ltd.) was used and annealed at 180°C or 110°C, respectively, to obtain non-peelable films (F-111) and (F-311), respectively. The release agent was applied to the resulting non-releasable films (F-111) and (F-311) in the same manner as above to form a release layer, thereby obtaining releasable films (F-213) and (F-413), respectively. The results are shown in Table 2.

[0111] [Table 2]

[0112] [MD shrinkage rate of first film, etc. [%]] As shown in Fig. 3(a), the first film 12 was cut into 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 A and the other designated 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 end of side A of the measurement sample, and the sample was hung with A facing up and B facing down, and placed in an oven at 150°C 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 taken as (AB)0, and the distance between A and B after heating at 150°C for 120 minutes was taken as (AB)0. 150 The value expressed by the following formula (2) when the above formula was used was taken as the shrinkage rate [%] in the MD direction. 100×((AB)0-(AB) 150 ) / (AB)0) (2)

[0113] [Storage modulus E' of the first film etc. at 150°C] 150 [Pa]] The storage modulus E' of each film obtained in First Film Preparations 1 to 3 was measured using a dynamic viscoelasticity measuring device DVA-200 (manufactured by IT Measurement & Control Co., Ltd.) in accordance with JIS K7198. Measurement samples were prepared by cutting each film into 5 mm in the transverse direction (hereinafter referred to as TD direction) and 30 mm in the MD direction. The deformation mode was tensile, and measurements were made at a strain of 0.08%, a frequency of 10 Hz, a heating rate of 10°C / min, and a temperature range of 20 to 200°C. The storage modulus E' at a temperature of 150°C was read from the obtained data, and E' 150 It was decided.

[0114] [Preparation of Resin Composition for Forming Sealing Layer] <Production and preparation of resin (A)> [Production Example of (Meth)acrylic Resin (a1-1) Solution] A reaction vessel (hereinafter simply referred to as the "reaction vessel") equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube was charged with 80 parts of ethyl acetate, 2 parts of methyl acrylate, 32 parts of methyl methacrylate, 60 parts of 2-ethylhexyl methacrylate, 3 parts of methacrylic acid, and 0.1 parts of 2,2'-azobisisobutyronitrile as an initiator, and the atmosphere inside the reaction vessel was replaced with nitrogen gas. The mixture was then heated to 75°C while stirring under a nitrogen atmosphere to initiate the reaction. The reaction solution was then reacted at 75°C for 4 hours. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate to obtain a (meth)acrylic resin (a1-1) intermediate solution. 3 parts of glycidyl methacrylate as a modifier was added to the resulting intermediate solution, which was then stirred at 60°C for 24 hours and diluted with ethyl acetate as necessary to produce a (meth)acrylic resin (a1-1) solution having methacryloyl groups. The weight average molecular weight (Mw) determined by the method described below was 110,000, and the solid content was 25%.

[0115] [Production Example of (Meth)acrylic Resin (a1-2) Solution] A (meth)acrylic resin (a1-2) intermediate solution was obtained in the same manner 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 Resonac) were added to the resulting intermediate solution as a modifier, and a (meth)acrylic resin (a1-2) solution was produced in the same manner as in the production of (meth)acrylic resin (a1-1). The molecular weight (Mw) was 120,000, and the solids content was 25%.

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

[0117] [Example of preparing a solution of epoxy resin (a3)] 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 measured using a GPC "LC-GPC system" (instrument name) manufactured by Shimadzu Corporation, and the weight average molecular weight (Mw) was calculated by conversion using polystyrene of known molecular weight as a standard substance. Device name: Shimadzu Corporation, LC-GPC system "Prominence" Columns: Four GMHXL columns manufactured by Tosoh Corporation and one HXL-H column manufactured by Tosoh Corporation were connected together. Mobile phase solvent: tetrahydrofuran Flow rate: 1.0mL / min Column temperature: 40℃

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

[0120] [Preparation of Resin Composition for Forming Sealing Layer] 100 parts by weight of the (meth)acrylic resin (a1-1) solid content was mixed in a 0.45 L container with 20 parts by weight of Mitsubishi Carbon MA100 as the colorant (Q-1), 5 parts by weight of Solsperse 5000 as the dispersant (D-1), and 200 parts by weight of methyl isobutyl ketone as the solvent, and the mixture was pre-dispersed using a disperser. 1,300 parts by weight of 1.0 mm diameter zirconia beads were then added, and the mixture was subjected to main dispersion 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 dilution solvent (a mixed solvent of methyl ethyl ketone and toluene) were sequentially added while stirring with a disper. The mixture was then stirred until it became sufficiently uniform, thereby obtaining a black coating liquid (1) for forming a resin composition layer for forming a sealing layer.

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

[0122] [Examples 2 to 7, 13 to 17, 23 to 24, Comparative Examples 1 to 14] As shown in Tables 3 to 5, a black coating liquid was prepared and an encapsulating 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 liquid 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), TIPAQUE CR-97 was used as colorant (Q-2) instead of colorant (Q-1), and DISPEARBYK142 was used as dispersant (D-2) instead of dispersant (D-1). A sealing sheet was obtained.

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

[0125] [Example 9] As shown in Table 3, 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 dilution solvent (a mixed solvent of methyl ethyl ketone and toluene) were sequentially added to 100 parts by mass of the solid content of the (meth)acrylic resin (a1-2) while stirring with a disper, and the mixture was stirred until it became sufficiently uniform to prepare a colorless coating liquid. An encapsulating sheet was obtained in the same manner as in Example 1.

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

[0127] [Example 10] As shown in Table 3, a high refractive index coating liquid 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 inorganic filler (P-1) instead of colorant (Q-1), and DISPEARBYK142 was used as dispersant (D-2) instead of dispersant (D-1). A sealing sheet was obtained.

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

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

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

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

[0132] [Example 22] As shown in Table 4, a black coating liquid was prepared in the same manner as in Example 12 except that the first film (F-101) was changed, and an encapsulating sheet was obtained. The initiator, crosslinking agent, inorganic filler, colorant, and dispersant used are described below. <Initiator> (B-1) Luperox 230 (trade name, manufactured by Arkema Yoshitomi Co., Ltd.) <Crosslinking agent> (E-1) jER YX8034 (product name, manufactured by Mitsubishi Chemical Corporation) (E-2) Curezol C11Z-A (trade name, manufactured by Shikoku Chemicals Corporation) <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) Typaque CR-97 (product name, manufactured by Ishihara Sangyo Kaisha) <Dispersant> (D-1) Solsperse 5000 (product name, manufactured by Lubrizol Corporation) (D-2) DISPEARBYK142 (product name, manufactured by BYK)

[0133] [Encapsulating sheet thickness T t , the thickness T of the resin composition layer a , thickness of the first film T1, thickness of the second film T2] A second film was placed on the resin composition layer side of the encapsulating sheet and adhered using a laminator at 90 ° C., and a test piece was prepared in which the first film, the resin composition layer, and the second film were laminated in this order. The test piece was cut into a size of 100 mm × 100 mm. The second film was peeled from the encapsulating sheet, and 10 equally spaced positions were determined from one end to the other end in the width direction of the second film. The thicknesses of the 10 positions were measured, and the average value was defined as the thickness T2 of the second film. Next, the thicknesses of the encapsulating sheet at 10 positions corresponding to the same positions as above were measured. The average value was defined as T t Then, the first film was peeled off from the resin composition layer, and the thickness of the peeled first film was measured at 10 points corresponding to the same positions as above. The average value was taken as T1. The thickness T of the resin composition layer a is T a =T t The thickness was measured using a MH-15M (Nikon Corporation). As the second film, (f-1) SP-PET-O1-BU6 (product name, manufactured by Mitsui Chemicals ICT Materia Co., Ltd.) was used.

[0134] [Peeling force P1 of the first film and peeling force P2 of the second film] A second film was laminated on the resin composition layer side of the encapsulating sheet and adhered using a laminator. The first film, the resin composition layer, and the second film were laminated in this order, and the laminate was cut into two strips measuring 25 mm in the TD direction and 100 mm in the MD direction to prepare test pieces. The second film was peeled off from the first test piece, and the exposed resin composition layer was attached to a stainless steel plate (hereinafter abbreviated as "SUS plate") with double-sided tape attached, thereby obtaining a measurement sample for measuring the peel strength of the first film. Next, the first film side of the second test piece was attached to a SUS plate with double-sided tape attached, thereby obtaining a measurement sample for measuring the peel strength of the second film. For each measurement sample, the peel force P1 of the first film and the peel force P2 [mN / 25 mm] of the second film were measured when peeled in a 180° direction at a speed of 300 mm / min in accordance with JIS Z 0237:2009 in an atmosphere of 23°C. The peel strength was measured using STB-125S (trade name, manufactured by AND Co.).

[0135] [evaluation] Unless otherwise specified, the evaluations were all rated as AA: very good, A: good, B: practically usable, and failure to achieve the target performance was rated as C. The evaluation results for each example and comparative example are shown in Tables 3 to 5.

[0136] <Evaluation of Appearance of Cured Resin Composition Layer> 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 side was placed on the first surface of a soda lime glass sheet (manufactured by Kawamura Kuzo Shoten Co., Ltd.) measuring 80 mm x 80 mm x 1.1 mm. Then, a 50 μm-thick TPX (Opulent X-44B, product name, manufactured by Mitsui Chemicals Tocello Co., Ltd.) and a 2 mm-thick PVC film (Celeb T, manufactured by Okamoto Corporation) were sequentially placed on the first film as cushioning materials, and cardboard was further placed thereon to prevent sticking. The laminate consisting of the soda lime glass sheet / resin composition layer / first film / cushioning material (TPX / PVC film) / cardboard was pressed from above against the substrate surface under conditions of 3 MPa and 100°C for 10 minutes, thereby adhering the resin composition layer to the soda lime glass sheet. After pressing, the cushioning material and cardboard were peeled off. The resulting test sample, consisting of a laminate of the first film, resin composition layer, and soda lime glass, was placed horizontally in a 150°C oven and heated for 120 minutes. The first film was then peeled from the heated test sample, and the appearance of the cured resin composition layer surface was visually evaluated. Zipping marks caused by zipping when peeling the heated first film from the cured resin composition layer, marks transferred from the press upper plate pattern to the cured resin composition layer surface, and marks transferred from the deflection caused by the cure shrinkage of the first film to the cured resin composition layer surface were collectively defined as areas of poor appearance. The appearance evaluation was performed according to the following criteria. Evaluation criteria AA: There is one or less appearance defect in total. A: A total of 2 or more but no more than 4 cosmetic defects. B: A total of 5 or more but not more than 7 areas with visual defects. C: A total of 8 or more areas with visual defects.

[0137] <Seamlessness> As shown in FIG. 4(a), the sealing sheet with the second film was cut to a size of 50 mm × 50 mm, the second film was peeled off, and the resin composition layer 11 side was placed on the first surface of a blue plate glass substrate 22 (manufactured by Kawamura Kyuzo Shoten Co., Ltd.) measuring 80 mm × 80 mm × 1.1 mm. Then, a 50 μm-thick TPX (Opulent X-44B, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) and a 2 mm-thick PVC film (Celeb T, manufactured by Okamoto Corporation) were sequentially placed on top of the first film 12 as cushioning materials, and cardboard was then placed on top to prevent sticking. The laminate consisting of the blue plate glass substrate 22 / resin composition layer 11 / first film 12 / cushioning material (TPX / PVC film) / cardboard was pressed from above against the blue plate glass substrate surface 22 under conditions of 3 MPa and 100°C for 10 minutes, thereby adhering the resin composition layer 11 to the blue plate glass substrate 22. After pressing, the cushioning material and cardboard were peeled off. The resulting test sample, consisting of a laminate of the first film 12, resin composition layer 11, and soda lime glass substrate 22, was placed horizontally in a 150°C oven and heated for 120 minutes. Thereafter, to observe the cross section of the cured resin composition layer 11', the heated first film 12' was cut into two pieces parallel to the MD at a position 30 mm from the TD end of the heated first film 12' while still attached. The heated first film 12' was peeled off, and the cross section of the cut piece with the cured resin composition layer 11' exposed was observed using a laser microscope VK-X100 (product name, manufactured by KEYENCE Corporation). 4(b), the position of the end of the lower surface of the cured resin composition layer 11′ (i.e., the end of the cured resin composition layer 11′ in contact with the soda lime glass substrate 22) was designated as H1, and the position 100 μm from H1 in the MD direction on the cured resin composition layer 11′ side (i.e., on the surface of the cured resin composition layer 11′ in contact with the soda lime glass substrate 22) was designated as H2. When a line perpendicular to the surface of the soda lime glass substrate 22 is drawn from H2, the intersection with the cured resin composition layer 11′ was designated as H3. The distance T between H2 and H3 at this time X (μm) was obtained, and the film thickness maintenance rate was calculated using the following formula (3). (T X / T a )×100 (3) The seamlessness when multiple panels were arranged using the values ​​of formula (3) was evaluated based on the following criteria. Evaluation criteria AA: The value of formula (3) is 50 or more. A: The value of formula (3) is 20 or more and less than 50. B: The value of formula (3) is 10 or more and less than 20. C: The value of equation (3) is less than 10.

[0138] <Embeddability> An embedded substrate 23 (a glass plate measuring 25 mm × 25 mm, on one side of which multiple recesses of 200 μm width, protrusions of 5 μm height, and protrusions of 200 μm width are formed in a grid pattern) was prepared to mimic the unevenness of the micro LED substrate. A schematic cross-sectional view of the embedded substrate 23 is shown in Figure 5. The sealing sheet with the 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 concave and convex portions were formed. Then, a 50 μm thick TPX (Opulent X-44B, product name, manufactured by Mitsui Chemicals Tocello Co., Ltd.) and a 2 mm thick PVC film (Celeb T, manufactured by Okamoto Co., Ltd.) were placed on the first film as cushioning materials, in that order, and cardboard was further placed on top to prevent sticking. A laminate consisting of a glass substrate / resin composition layer / first film / cushioning material (TPX / PVC film) / cardboard was pressed against the substrate surface from above under conditions of 3 MPa and 100°C for 10 minutes, and the resin composition layer was filled into the recesses of the test substrate to form a sealing layer. After pressing, the cushioning material and cardboard were peeled off. Four corners of 15 randomly selected recesses (60 locations in total) of the obtained sealing layer and test substrate with the first film were observed with a microscope from the glass plate side, and the embeddability was evaluated based on the number of locations where gaps appeared, according to the following criteria. Evaluation criteria AA: 56 or more gap-free areas. A: There are 41 or more and 55 or fewer gap-free areas. B: 29 or more and 40 or less recesses without gaps. C: 28 or fewer recesses 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 plate glass substrate 23: Embedded substrate

Claims

1. An encapsulating sheet for encapsulating an optical semiconductor used in a display using an optical semiconductor as a light source, The sealing sheet includes a first film and a resin composition layer for forming a sealing layer laminated directly on the first film, the first film is a biaxially oriented polyester film or a biaxially oriented polyolefin film, The shrinkage percentage of the first film measured under the following conditions is 1.0% or less: The unheated first film 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. The first film has a storage modulus E' at 150°C in a tensile mode of the first film. １５０ [x10 ８ Pa], the thickness of the first film is T ｌ When expressed as [μm], the following formula (1) is satisfied: 40 ≦ (E' １５０ ) １／２ × T ｌ ≦ 230 (1) The peel force P between the first film and the resin composition layer ｌ is 8 to 150 mN / 25 mm, The thickness T of the first film １ The encapsulating sheet is characterized in that the thickness is 20 to 120 μm.

2. The sealing sheet according to claim 1, wherein the first film is a biaxially oriented polyester film.

3. The encapsulating sheet according to claim 1, wherein the first film is an annealed product.

4. 2. The encapsulating sheet according to claim 1, wherein the resin composition layer contains at least one resin selected from the group consisting of a (meth)acrylic resin, an epoxy resin, and a urethane resin.

5. The encapsulating sheet according to claim 4, wherein the resin composition layer contains 50% or more of a (meth)acrylic resin when the solid content of the resin composition layer is taken as 100% by mass.

6. The encapsulating sheet according to claim 1, wherein the optical semiconductor is a micro LED.

7. A display comprising a sealing layer which is a cured product of the resin composition layer according to any one of claims 1 to 6.

Images