Sealing sheet and method for manufacturing display

Abstract

The present invention provides a sealing sheet, a display, and a method for manufacturing the same, which are excellent in embedding properties and suppression of die shifting when used for sealing micro-LEDs in displays that use micro-LEDs as light sources. The problem is solved by a sealing sheet comprising a first film, a resin composition layer, and a second film in sequence, wherein the first film has a peeling layer on the surface facing the resin composition layer, the thickness Ta of the resin composition layer is 2 μm to 100 μm, the thickness Th of the second film is 12 μm to 188 μm, Ta and Th satisfy the relationship of 0.1≦Ta / Th≦2, and the maximum value (tanδ maximum value) of the loss tangent of the resin composition layer obtained by dynamic viscoelasticity measurement is 0.6 to 2.2 in the range of ‑50°C to 80°C.

Description

[0001] This application claims priority based on Japanese patent application No. 2023-202350, filed on November 30, 2023, and all disclosures thereof are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to a sealing sheet, and more particularly, to a sealing sheet comprising a resin composition layer for sealing micro-LEDs used in a display that uses the micro-LEDs as light sources. The present disclosure also relates to a display equipped with the resin composition layer and a method for manufacturing the same. Background Art

[0003] In recent years, with regard to displays, with the goal of further high performance, the development of various light-emitting elements is being actively carried out. Specifically, various display specifications such as backlit displays using liquid crystals or quantum dots, displays using self-luminous elements such as mini / micro light emitting diodes (LEDs) or organic electroluminescence (EL), plasma displays, and electrophoretic displays have been studied, and a wide range of applications ranging from large displays such as signage or televisions to small-sized applications such as tablets, personal computers, smart phones, and wearable devices have been studied. In particular, the development of displays using LEDs is progressing day by day, and a thermosetting resin composition for sealing LED elements is described in Japanese Patent Laid-Open No. 2023-12051 (Patent Document 1) and International Publication No. 2021 / 200035 (Patent Document 2). Japanese Patent Application Laid-Open No. 2021-111774 (Patent Document 3) describes a method for manufacturing a micro-LED light-emitting device in which a barrier layer is pressurized and deformed to seal the micro-LED. Micro-LED displays are attracting the most attention as a next-generation display technology. Summary of the Invention

[0004] [Problems to be solved by the invention]

[0005] In recent years, miniaturization of LED components has progressed, with the spacing between LED components and the distance from the substrate becoming increasingly narrow. While the resin sheets used to seal optical semiconductor components, as described in Patent Documents 1 and 2, have excellent heat resistance and handleability, they lack sufficient flowability and are therefore insufficient for filling the voids (embedding) of micro-sized LED components. When gaps exist between the LED components and the sealing resin composition, light refracts and reflects in the gaps, causing light mixing and adversely affecting display visibility.

[0006] On the other hand, when embedding micro-LEDs using the encapsulating sheet described in Patent Document 3, uneven resin flow applies stress in one direction to the micro-LEDs, causing the micro-LEDs to shift from the substrate (die shift). Die shift causes poor micro-LED light emission, requiring repair work, which increases production time and costs.

[0007] The present disclosure is made in view of the above-mentioned problems, and its object is to provide a sealing sheet having excellent embedding properties and suppression of die shifting (die shifting properties) even when applied to a display using micro LEDs as light sources, a display having a resin composition layer, and a method for manufacturing the same.

[0008] Furthermore, a further object is to provide a sealing sheet having excellent light controllability, a display having a resin composition layer, and a method for producing the same, so as to prevent the visibility of the display from being reduced due to refraction or reflection of light.

[0009] [Technical means to solve the problem]

[0010] The present inventors have conducted diligent research and have found that the above-mentioned problems can be solved by the sealing sheet shown below, thereby completing the present inventions [1] to [8] below.

[0011] [1]: A sealing sheet for sealing a micro-LED used in a display using the micro-LED as a light source, the sealing sheet being sequentially provided with a first film, a resin composition layer, and a second film, wherein the first film has a peeling layer on a surface facing the resin composition layer, the thickness Ta of the resin composition layer is 2 μm to 100 μm, the thickness Th of the second film is 12 μm to 188 μm, Ta and Th satisfy formula (1), and the maximum value of the loss tangent of the resin composition layer obtained by dynamic viscoelasticity measurement in the range of -50°C to 80°C is 0.6 to 2.2.

[0012] Formula (1) 0.1 ≦ Ta / Th ≦ 2

[0013] [2]: The sealing sheet according to [1], wherein the Young's modulus of the second film is 1 GPa to 6 GPa.

[0014] [3]: The sealing sheet according to [1] or [2], wherein the ratio of the root mean square height Sq of the surface of the first film in contact with the resin composition layer as specified in ISO 25178 to the thickness Ta of the resin composition layer is 30% or less.

[0015] [4]: The sealing sheet according to any one of [1] to [3], wherein the resin composition layer has a pencil hardness of 5B to 2H.

[0016] [5]: The sealing sheet according to any one of [1] to [4], wherein the resin composition layer contains a resin (A),

[0017] The resin (A) includes at least one selected from the group consisting of acrylic resin (a1), urethane resin (a2), and epoxy resin (a3).

[0018] [6]: The sealing sheet according to any one of [1] to [5], wherein the resin composition layer contains a colorant (B).

[0019] [7]: The sealing sheet according to any one of [1] to [6], wherein the resin composition layer contains a polymerization initiator (C).

[0020] [8]: A display using a micro LED having a resin composition layer of the sealing sheet according to any one of [1] to [7] as a light source.

[0021] [9]: A method for manufacturing a display using micro LEDs as light sources, comprising the following steps (1) to (6).

[0022] (1) a step of preparing a sealing sheet according to any one of [1] to [4], in which a first film, a resin composition layer for forming a sealing layer, and a second film are sequentially arranged;

[0023] (2) a step of preparing a sealing object in which a plurality of micro LEDs are arranged at intervals on one surface of a substrate;

[0024] (3) a step of peeling the first film from the sealing sheet to expose the resin composition layer for forming the sealing layer;

[0025] (4) a step of placing the exposed resin composition layer for forming a sealing layer so as to cover the plurality of micro LEDs;

[0026] (5) a step of flowing a resin composition layer for forming a sealing layer and filling the space between the plurality of micro-LEDs;

[0027] (6) A step of peeling off the second film.

[0028] [Effects of the Invention]

[0029] According to the present disclosure, it is possible to provide a sealing sheet having excellent embedding properties and suppression of die displacement, a display having a resin composition layer, and a method for producing the same, even when applied to a display using micro LEDs as a light source.

[0030] Furthermore, according to the present disclosure, in addition to the above, a sealing sheet having excellent light controllability, a display having a resin composition layer, and a method for producing the same can be provided to prevent degradation of display visibility due to refraction and reflection of light. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic cross-sectional view showing an example of a laminated structure of a sealing sheet.

[0032] Figure 2 (a)~ Figure 2 (c-2) is a schematic cross-sectional view showing a step of sealing a light-emitting element on a substrate having the light-emitting element.

[0033] Figure 3 This is a cross-sectional view showing an example of a test substrate that simulates a micro-LED substrate.

[0034] Explanation of symbols

[0035] 1: Sealing sheet

[0036] 2: Resin composition layer

[0037] 2': Sealing layer

[0038] 3: First film

[0039] 4: Second film

[0040] 5: Light-emitting element (micro LED)

[0041] 6: Substrate

[0042] 7: Glass substrate DETAILED DESCRIPTION

[0043] The present disclosure will be described in detail below. The embodiments described below are examples of the present disclosure. The present disclosure is not limited to the embodiments described below, but also includes modifications that can be implemented without changing the gist of the present disclosure.

[0044] In this specification, numerical ranges designated with "to" include the numerical values ​​before and after the "to" as the lower and upper limits. (Meth)acrylic acid refers to both acrylic acid and methacrylic acid. Unless otherwise specified, each component mentioned in this specification may be used alone or in combination of two or more. When two or more components are used in combination, the total content is used.

[0045] [Form of sealing sheet]

[0046] An example of the sealing sheet disclosed in the present invention is shown in Figure 1 .like Figure 1As shown, the sealing sheet 1 is sequentially provided with a first film 3, a resin composition layer 2 and a second film 4. A plurality of resin composition layers may be provided. Figure 1 In the case of the three-layer structure shown above, a production method is preferably used in which the resin composition layer is formed on the second film and then the first film is bonded thereto.

[0047] After manufacturing the sealing sheet, or while manufacturing the sealing sheet, the sealing sheet is wound around a core in a roll, thereby obtaining a sealing sheet roll. The length of the roll can be designed according to the purpose. From the perspective of improving productivity, it is preferably more than 50m, and more preferably more than 100m. From the perspective of manufacturing yield, the length of the roll is preferably set to less than 10000m. When the sealing sheet is set to a roll form, it is preferred that the first film is arranged on the outside of the roll.

[0048] The sealing sheet disclosed herein is used to seal microLEDs used in displays that utilize microLEDs as light sources. The resin composition layer is preferably directly in contact with the microLEDs for sealing. The microLEDs are not particularly limited and are preferably disposed on a substrate such as acrylic, urethane, polycarbonate, epoxy, polyimide, glass, paper, cloth, aluminum, ceramic, or polyethylene terephthalate and have electrode sites. The microLEDs may be disposed singly or in multiple configurations.

[0049] Because the resin composition layer has high conformability to uneven surfaces, it is preferably used to conform to multiple micro-LEDs arranged on a substrate, filling the gaps between the micro-LEDs. By filling the gaps between the micro-LEDs with the resin composition layer, a sealing layer comprising the resin composition layer is formed. The sealing layer has the function of securing adjacent micro-LEDs to prevent them from falling out. In particular, the resin composition layer is preferably used as a sealing layer for a micro-LED display panel.

[0050] MicroLEDs are tiny LED elements (chips) with a diameter of 50μm or 100μm or less. By mounting multiple microLEDs on a substrate with wiring or circuitry, a display using multiple optical semiconductor elements as light sources is formed. MicroLEDs are composed of LED elements such as GaAs, GaP, AlGaInP, and InGaN, along with a sealing resin, a package substrate, and electrodes. Their operating temperature is 25°C to 60°C.

[0051] Below, use Figure 2 (a)~ Figure 2 An example of the step of forming the sealing layer in (c-2) will be described.

[0052] Step (a): Sealing sheet placement step

[0053] like Figure 2As shown in (a), after the first film 3 is peeled off from the sealing sheet 1 to expose the resin composition layer 2, the resin composition layer 2 side of the sealing sheet is placed on a substrate 6 having micro LEDs 5 as light-emitting elements in a manner directly covering the micro LEDs.

[0054] In this specification, the number of micro-LEDs is not particularly limited. In display applications, the number of micro-LEDs used is determined by the display size or the number of pixels. In addition, the luminous color of the micro-LED is not particularly limited, and examples of luminous colors include red, green, and blue. The size of the micro-LED is preferably less than 100 μm in thickness and 40,000 μm in area when viewed from above. 2 More preferably, the thickness is 50 μm or less and the area in plan view is 10,000 μm. 2 The thickness is preferably 20 μm or less and the area is preferably 2,500 μm when viewed from above. 2 The following sizes.

[0055] The spacing between micro-LEDs mounted on the substrate is, for example, 10 μm to 5,000 μm. When a group of red, green, and blue micro-LEDs is mounted on the substrate as a pixel, the spacing between pixels is, for example, 10 μm to 2,000 μm, preferably 20 μm to 1,800 μm, and more preferably 500 μm to 1,500 μm. The spacing between micro-LEDs within a pixel is, for example, 10 μm to 200 μm, preferably 10 μm to 100 μm, and more preferably 20 μm to 60 μm.

[0056] Process (b): Pressing process

[0057] like Figure 2 As shown in (b), the resin composition layer 2 is made to flow by pressing and is filled around the micro LEDs or between the micro LEDs. The resin composition layer 2 filled around the micro LEDs or between the micro LEDs becomes a sealing layer 2'. The pressing method is not particularly limited, but hot pressing and vacuum pressing are preferred. From the perspective of the filling properties of the resin composition layer, the temperature during pressing is preferably 20°C to 200°C, more preferably 30°C to 150°C, further preferably 40°C to 130°C, and most preferably 60°C to 110°C.

[0058] In order to improve the adhesion with the micro LED or adherend, heat aging may be further performed after pressing. The heating temperature is preferably 40°C to 250°C, more preferably 80°C to 220°C, and further preferably 100°C to 190°C. The heating time is preferably 30 minutes to 300 minutes, more preferably 60 minutes to 240 minutes, and further preferably 90 minutes to 180 minutes. By setting the heating temperature and heating time, the residual stress of the resin composition layer can be removed and the close contact surface can be smoothed. Heat aging may also be implemented after step (c) described later. The second film may be peeled off before heat aging or after heat aging.

[0059] Step (c): Etching step

[0060] In step (c), etching can be performed as needed to remove the sealing layer on the optical semiconductor element or to thin it. When step (c) is performed, it is preferably performed after peeling off the second film. By removing the excess sealing layer, the brightness of the micro LED is increased, ensuring visibility during light emission. The thickness of the sealing layer after etching is preferably as follows: Figure 2 As shown in (c-1), the thickness of the micro LED is the same as that of the micro LED, or as shown in (c-1) Figure 2 As shown in (c-2), the thickness of the micro-LED is less than that of the micro-LED. In addition, even if the sealing layer is not completely removed from the micro-LED, it can be substantially removed, and a small amount of thin film can be left. In addition, step (c) can be omitted if sufficient brightness can be ensured.

[0061] The etching method is not particularly limited, and preferred examples include wet etching methods such as chemical polishing using a reagent, 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 perspective of reducing surface unevenness, plasma etching, or a combination of wet etching and dry etching is preferred.

[0062] Plasma etching conditions include, for example, dry etching in an anisotropic plasma apparatus using a CF4 / O2 / N2 mixed gas at a power of 1500 W to 3000 W for 180 seconds to 600 seconds. In this case, the CF4 gas supply rate can be, for example, 50 sccm to 100 sccm, the O2 gas supply rate can be, for example, 500 sccm to 1000 sccm, and the N2 gas supply rate can be, for example, 50 sccm to 100 sccm.

[0063] The sealing sheet of the present disclosure can form a sealing layer from the resin composition layer through the above-described steps (a) to (c). Next, the constituent components of the sealing sheet of the present disclosure will be described in detail with reference to preferred examples.

[0064] [First Film]

[0065] The first film is not particularly limited. Examples thereof include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin films such as polypropylene and polyethylene; polyvinyl chloride films; polyurethane films; nylon films; polyolefin films; triacetylcellulose films; and cycloolefin films. From a handling perspective, polyester films and polyolefin films are preferred.

[0066] The first film has a release layer on the surface facing the resin composition layer. The release layer is preferably formed by applying a release agent such as a silicone resin, alkyd resin, fluororesin, or melamine resin to the film. From the perspective of handling (preventing unintended separation), a release layer using a silicone resin is more preferred.

[0067] The peel force Pl of the first film is preferably 0.1 gf / 20 mm to 3 gf / 20 mm, more preferably 0.3 gf / 20 mm to 2 gf / 20 mm, and still more preferably 0.5 gf / 20 mm to 1 gf / 20 mm.

[0068] The release force P1 of the first 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 release force, increasing the surface roughness or the amount of release agent applied is effective. To increase the release force, the opposite adjustment can be performed.

[0069] The peel force Pl of the first film can be measured, for example, by attaching the second film of the sealing sheet to a stainless steel (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 under an environment of 23°C and a relative humidity of 50%.

[0070] The first film may further include a functional layer in addition to the release layer. Specific examples of the functional layer include an antistatic layer and an anti-blocking layer.

[0071] The thickness Tl of the first film is preferably 2 μm to 250 μm, more preferably 10 μm to 100 μm, and even more preferably 20 μm to 60 μm. If the first film is provided with a release layer or a functional layer, the thickness Tl includes both the release layer and the functional layer. By setting Tl to 2 μm to 250 μm, the transfer of the first film's fluctuations to the resin composition layer can be controlled, resulting in a uniform resin composition layer.

[0072] The first film is preferably directly laminated with the resin composition layer. When the first film is directly laminated with the resin composition layer, on the surface of the first film in contact with the resin composition layer, the ratio of the root mean square height Sq of the surface roughness according to the International Organization for Standardization (ISO) 25178 to the thickness Ta of the resin composition layer is preferably 30% or less, more preferably 15% or less, and further preferably 7.5% or less. By setting it to 30% or less, the surface roughness transferred to the resin composition layer is controlled, and the resin composition layer is fully smoothed in the pressing process described later, thereby improving the die shiftability and adhesion. The root mean square height Sq can be measured, for example, by the method described in the examples described later.

[0073] The root mean square height Sq value is preferably 0.01 μm to 2 μm, more preferably 0.04 μm to 1.5 μm, and even more preferably 0.1 μm to 1.5 μm.

[0074] Furthermore, the root mean square height Sq can be adjusted by performing a demolding treatment on the release layer of the first film. For example, it can be adjusted by adjusting the type of release agent, the amount of release agent applied, or the method of applying the release agent. To increase the root mean square height Sq, effective methods include reducing the amount of release agent applied, accelerating drying after application, and adding fillers to the release agent. To decrease the root mean square height Sq, the opposite adjustment can be performed. Alternatively, a method of transferring the relief using a film or carrier material having a predetermined root mean square height Sq can be employed.

[0075] [Second film]

[0076] The second film is not particularly limited. Examples thereof include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin films such as polypropylene and polyethylene; polyvinyl chloride films; polyurethane films; nylon films; polyolefin films; triacetylcellulose films; and cycloolefin films. From a handling perspective, polyester films and polyolefin films are preferred.

[0077] The second film is preferably directly laminated on the resin composition layer.

[0078] The Young's modulus of the second film is preferably 1 GPa to 6 GPa, more preferably 2 GPa to 5 GPa, and even more preferably 3 GPa to 5 GPa. Setting the Young's modulus to 1 GPa to 6 GPa allows uniform pressure to be applied to the resin composition layer in the pressing step described later while controlling the flow of the resin composition layer, thereby improving embedding properties.

[0079] The Young's modulus of the second film can be adjusted by the crystallization state and orientation direction. By increasing the degree of crystallinity or converting random amorphous chains into oriented amorphous chains, a high Young's modulus can be achieved. To reduce the Young's modulus, the opposite adjustment can be performed. When the Young's modulus is set to 1 GPa to 6 GPa, a polyester film or a polyolefin film is preferably used, and a polyethylene terephthalate film is more preferably used.

[0080] The Young's modulus of the second film can be measured by, for example, the method described in Examples below.

[0081] The second film preferably has a release layer on the surface facing the resin composition layer. The release layer is preferably formed by applying a release agent such as a silicone resin, alkyd resin, fluororesin, or melamine resin to the film. From the perspective of handling (preventing unintended separation), a release layer using a silicone resin is more preferred.

[0082] The peel force Ph of the second film is preferably 0.5 gf / 20 mm to 5 gf / 20 mm, more preferably 0.8 gf / 20 mm to 4 gf / 20 mm, and even more preferably 1.0 gf / 20 mm to 3 gf / 20 mm.

[0083] The release force Ph of the second film can be adjusted by the release layer's release treatment. 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 release force, increasing the surface roughness or the amount of release agent applied is effective. To increase the release force, the opposite adjustment can be performed.

[0084] The peeling force Ph of the second film is preferably greater than the peeling force Pl of the first film. Specifically, the value of Ph / Pl is more preferably 1.1 to 11, and even more preferably 1.1 to 6.

[0085] The peel force Ph of the second film can be measured, for example, by peeling the first film from the sealing sheet, attaching the exposed resin composition layer to a SUS plate, and further peeling the second film from the resin composition layer at a peel angle of 180° and a peel speed of 300 mm / min under an environment of 23°C and a relative humidity of 50%.

[0086] The second film may further include a functional layer in addition to the release layer. Specific examples of the functional layer include an antistatic layer and an anti-blocking layer.

[0087] The thickness Th of the second film is 12 μm to 188 μm, more preferably 12 μm to 100 μm, and even more preferably 20 μm to 60 μm. If the second film includes a release layer or a functional layer, the thickness Th includes both the release layer and the functional layer. By setting Th to 12 μm to 188 μm, the pressure applied to the resin composition layer during the pressing step described later is controlled, allowing the resin composition layer to flow uniformly, thereby improving embedding properties, die shifting properties, and adhesion.

[0088] [Resin composition layer]

[0089] The resin composition layer preferably contains the resin (A), more preferably contains the colorant (B) and / or the polymerization initiator (C), and may also contain other components.

[0090] In the present disclosure, the resin (A) is a substance having a function of bonding and fixing objects together as an adhesive. As a specific example, the resin (A) has a function of bonding and fixing to a substrate having micro-LEDs or the micro-LEDs.

[0091] The maximum value of the loss tangent (tan δ maximum value) of the resin composition layer of the present disclosure obtained by dynamic viscoelasticity measurement within the range of -50°C to 80°C is 0.6 to 2.2, more preferably 0.9 to 1.7, and even more preferably 1.1 to 1.5.

[0092] The maximum value of tan δ is, for example, the value of loss tangent (tan δ) when the tan δ curve reaches a maximum. In addition, when there are two or more maximum values, the maximum value of loss tangent (tan δ) is indicated.

[0093] When the maximum value of tan δ is 0.6 or greater, the pressure applied to the resin composition layer during the pressing process is well transferred, reducing the stress applied to the micro-LEDs, thereby improving the die displacement resistance. When the maximum value of tan δ is 2.2 or less, the pressure applied to the resin composition layer during the pressing process is well absorbed, following the unevenness of the micro-LEDs and improving the embedding property.

[0094] The maximum tan δ value of the present disclosure can be adjusted by the type or composition of the resin (A), the type, dispersion state, or content of the colorant (B), the type or content of the polymerization initiator (C), and the type or content of other components such as crosslinking agents or monomers.

[0095] When the resin (A) contains a (meth)acrylic resin (a1), the maximum tan δ value can be increased compared to when the resin (A) contains a urethane resin (a2). However, this is not limited to this value depending on the resin composition. When the resin (A) contains a (meth)acrylic resin (a1), the maximum tan δ value can be reduced by increasing the content of an alkyl methacrylate such as methyl methacrylate. To increase the maximum tan δ value, the opposite adjustment can be made.

[0096] When carbon black is included as the colorant (B), the maximum tan δ value can be lowered compared to when a metal oxide pigment is included. However, this is not limited to this value depending on the dispersion state of the particles. When the colorant (B) contains carbon black, the maximum tan δ value can be lowered by increasing the carbon black content. To increase the maximum tan δ value, the opposite adjustment can be made.

[0097] When a thermal polymerization initiator is contained as the polymerization initiator (C), the maximum value of tan δ can be increased by increasing the content. When it is desired to lower the maximum value of tan δ, it is only necessary to adjust the content inversely.

[0098] When the resin composition layer contains a crosslinking agent as another component, the maximum value of tan δ can be increased by increasing the content. When it is desired to lower the maximum value of tan δ, it is sufficient to adjust the content in the opposite direction.

[0099] By increasing the content of a low-viscosity monomer, the maximum value of tan δ can be lowered. To increase the maximum value of tan δ, the opposite adjustment can be made. Specific examples of low-viscosity monomers include 1,6-hexanediol diacrylate.

[0100] The resin composition layer of the present disclosure preferably has a loss tangent (tan δ40) at 40°C, as measured by dynamic viscoelasticity, of 0.6 to 2.0, more preferably 0.8 to 1.9, and even more preferably 1.1 to 1.5. By setting the tan δ40 to 0.6 to 2.0, the pressure applied to the resin composition layer during the pressing process is appropriately transmitted, improving embedding properties and die shifting properties.

[0101] In order to control the diffusibility of the pressure applied to the resin composition layer within the temperature range of 20°C to 200°C, which is a preferred temperature range for the pressing process, the loss tangent at 40°C (tanδ40) is adjusted to 0.6 to 2.0, thereby achieving a balance between the loss tangent at 20°C to 40°C and the loss tangent at 40°C to 200°C without deviation.

[0102] Tan δ40 can be adjusted by the type and composition of the resin (A) and the type and dispersion state of the colorant (B). Specifically, the same adjustment method as that for the tan δ peak intensity can be used.

[0103] The peak top temperature of the loss tangent (tan δ peak temperature) obtained by dynamic viscoelasticity measurement of the resin composition layer disclosed herein refers to the temperature at which the tan δ curve reaches a maximum. When there are two or more peaks, the lowest peak temperature is indicated. The tan δ peak temperature is preferably -30°C to 70°C, more preferably -20°C to 50°C, even more preferably -10°C to 30°C, and most preferably -10°C to 10°C.

[0104] When the tan δ peak temperature is within a range of -30°C to 70°C, the residual stress of the resin can be sufficiently removed during the heat aging step, thereby improving the adhesion to the adherend.

[0105] Furthermore, the tan δ peak temperature of the present disclosure can be adjusted by the type or composition of resin (A). When resin (A) contains a (meth)acrylic resin (a1), the tan δ peak temperature can be increased by increasing the content of monomers having a high glass transition temperature (Tg) of the homopolymer. To lower the tan δ peak temperature, the opposite adjustment can be performed. The glass transition temperature (Tg) of the homopolymer in the present disclosure can be the value described in "POLYMER HANDBOOK, 1999, FOURTH EDITION."

[0106] The loss tangent (tan δ) is a ratio of loss elastic modulus to storage elastic modulus obtained by dynamic viscoelasticity measurement in a tensile mode at a frequency of 10 Hz and at -50°C to 150°C.

[0107] Dynamic viscoelasticity and loss tangent (tan δ) in the present disclosure are measured by the method described in Examples described later. In addition, when the resin composition layer includes any one of a polymerization initiator (C) and a cross-linking agent, polymerization / cross-linking reaction during measurement is an unfinished state. In addition, the determination is preferably measured to a sheet of thickness 50 μm or more, and when a sheet less than the thickness is measured, two groups of sealing sheets without the first film can also be prepared, and resin composition layers are adhered to each other using a laminator, and the laminate of the second film / resin composition layer / second film is made, and the second film of one of the faces of the laminate is further peeled off, and the resin composition layer of the sealing sheet is repeatedly adhered, thus after being laminated in a manner of becoming more than 50 μm, dynamic viscoelasticity is measured.

[0108] From the perspective of embedding properties and die shifting properties, the thickness Ta of the resin composition layer is 2 μm to 100 μm, preferably 5 μm to 60 μm, more preferably 10 μm to 40 μm, and further preferably 10 μm to 30 μm. From the perspective of light shielding properties, it is particularly preferably 13 μm to 30 μm.

[0109] By setting the thickness Ta of the resin composition layer to 2 μm to 100 μm, the pressure applied to the resin composition layer during the pressing process is appropriately distributed and uniform, thereby improving embedding properties and die shifting resistance. The resin composition layer may be a single layer or a stack of two or more layers. In the case of two or more layers, the total thickness is the total thickness.

[0110] The thickness Ta of the resin composition layer can be adjusted by the method for forming the resin composition layer described below. The thickness Ta in the present disclosure is measured by the method described in the examples described below.

[0111] The thickness Ta of the resin composition layer satisfies the formula (1) representing the ratio to the thickness Th of the second film: 0.1≦Ta / Th≦2, more preferably 0.2≦Ta / Th≦1.5, and even more preferably 0.2≦Ta / Th≦1.2.

[0112] By setting 0.1≦Ta / Th≦2, the pressure transfer to the resin composition layer in the pressing step described later is controlled, and the resin composition layer flows uniformly, thereby improving embedding properties and die shifting properties.

[0113] From the perspective of embedding properties and die shifting resistance, the pencil hardness of the resin composition layer is preferably 5B to 2H, more preferably 4B to H, and even more preferably 3B to F. By setting the pencil hardness of the resin composition layer to 5B to 2H, the pressure applied to the resin composition layer during the pressing step is appropriately dispersed and sufficiently uniform, thereby improving embedding properties and die shifting resistance.

[0114] The pencil hardness of the resin composition layer can be adjusted by the type of resin (A), the content of the polymerization initiator (C), and the content of the monomers. Increasing the content of the polymerization initiator (C) results in a harder layer, while increasing the content of the monomers results in a softer layer.

[0115] The pencil hardness of the resin composition layer in the present disclosure is measured by the method described in Examples below. When the resin composition layer contains any of a polymerization initiator (C) and a crosslinking agent, the polymerization / crosslinking reaction is in an incomplete state during measurement.

[0116] [Method for Forming Resin Composition Layer]

[0117] The method for forming the resin composition layer is not particularly limited. A suitable example includes a method of applying a resin composition obtained by adding an arbitrary solvent to the components constituting the resin composition layer. The purpose of adding the solvent is to adjust the viscosity to a level suitable for coating and to adjust the film thickness.

[0118] Coating can be performed using known coating machines or methods, such as a notch wheel coater, die coater, roll coater, lip coater, reverse coater, gravure coater, rod coater, curtain coater, dip coating, spin coating, screen coating, or casting. The solvent contained in the resin composition can be removed by a drying step after coating.

[0119] As a preferred embodiment, resin combination can be applied to supports such as the first film and the second film, and then a hot air drying oven, an infrared heater, etc. are used to heat and dry the coated film, thereby forming a resin combination layer on one side of the support. And then, in order to promote the crosslinking density of the resin combination layer, it is preferably carried out under specific temperature conditions to stand such an aging treatment or irradiate ultraviolet light (ultraviolet, UV) etc. In addition, it is also possible to use a laminating machine to be transferred to other supports such as the first film, the second film, and the base material after coating.

[0120] [Resin composition]

[0121] The resin composition can be obtained by mixing the solvent and the components constituting the resin composition layer while stirring. As the components constituting the resin composition layer, it is preferably containing resin (A), more preferably containing colorant (B) and / or polymerization initiator (C), and may also contain other components. Any solvent is used for the purpose of adjusting the processing adaptability such as viscosity when mixing the components constituting the resin composition layer. For example, solvents that are compatible with the resin (A) such as esters, ether esters, ethers, alcohols, aromatics, etc. can be suitably used. Specifically, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, cyclohexanone, toluene, xylene, isopropyl alcohol, N-methyl-2-pyrrolidone, etc. can be listed as suitable examples.

[0122] A known stirring device can be used for stirring, and preferably a disperser, a mixer, an oscillator, a homogenizer, or the like.

[0123] To obtain the resin composition, the following production process can be adopted: first, a mixture is prepared by mixing the resin (A) or an arbitrary solvent with the colorant (B), and second, a two-stage or more production process is performed by adding the resin (A), the polymerization initiator (C), and other components as needed.

[0124] [Resin (A)]

[0125] The weight average molecular weight (Mw) of the resin (A) is preferably 1,000,000 or less. It is more preferably 300,000 or less, and even more preferably 150,000 or less. By setting the weight average molecular weight (Mw) of the resin (A) to 1,000,000 or less, the entanglement of the molecular chains during the heat aging step becomes easier to untangle, thereby improving the adhesion.

[0126] The lower limit of the weight average molecular weight (Mw) of the resin (A) is not particularly limited, but is preferably 400 or greater, more preferably 900 or greater, even more preferably 3000 or greater, further preferably 5000 or greater, and particularly preferably 10,000 or greater. By setting the weight average molecular weight (Mw) of the resin (A) to 400 or greater, the coating film strength of the resin composition layer is improved.

[0127] The weight average molecular weight (Mw) is a value in terms of polystyrene measured by gel permeation chromatography (GPC). The weight average molecular weight (Mw) in the present disclosure is measured by the method described in the Examples below.

[0128] The glass transition temperature (Tg) of the resin (A) is preferably -30°C to 80°C, more preferably -20°C to 60°C, further preferably -15°C to 40°C, further preferably -10°C to 20°C, and particularly preferably -10°C to 10°C. By setting the temperature to -30°C to 80°C, the residual stress of the resin (A) after the pressing step is reduced, thereby achieving suitable adhesion.

[0129] Regarding the glass transition temperature (Tg) of resin (A) in this disclosure, if the polymerization / crosslinking reaction of resin (A) occurs due to heat or light, the polymerization / crosslinking reaction is incomplete at the time of measurement. The glass transition temperature (Tg) of resin (A) in this disclosure is measured using the method described in the Examples below.

[0130] Resin (A) can be used alone or in combination of two or more. Based on the total amount (100% by mass) of the resin composition layer, the content of resin (A) is preferably 10% to 98% by mass, more preferably 25% to 95% by mass, and further preferably 60% to 90% by mass. In the case of comprising two or more resins (A), the content of any resin (A) is preferably 5% to 98% by mass, and the total content is preferably in the range. By setting the content of resin (A) to 10% to 98% by mass, the compatibility with colorant (B) becomes good and light-shielding property improves.

[0131] Preferred examples of the resin (A) include (meth)acrylic resins (a1), urethane resins such as polyurethane resins or polyurethane urea resins (a2), epoxy resins (a3), maleic acid resins, styrene-maleic acid copolymers, polystyrene resins, polybutadiene resins, polyester resins, condensation-type polyester resins, addition-type polyester resins, melamine resins, polycarbonate resins, oxetane resins, phenoxy resins, polyimide resins, polyamideimide resins, alkyd resins, amino resins, polyamide resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, fluororesins, butyral resins, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, polyvinyl acetate, vinyl-based resins, rubber-based resins, cyclized rubber-based resins, celluloses, polyethylene (high-density polyethylene (HDPE), low-density polyethylene (LDPE)), and the like. From the viewpoint of embedding properties, it is preferred to contain at least one of (meth)acrylic resin (a1), urethane resin (a2), and epoxy resin (a3). Furthermore, from the viewpoint of adhesion, it is more preferred to contain (meth)acrylic resin (a1).

[0132] Resin (A) preferably has one or more functional groups that can undergo polymerization / crosslinking reactions induced by heat or light. The functional groups can be appropriately selected based on their reactivity with the resin (A) or with the polymerization initiator (C) or crosslinking agent described below. Self-crosslinking functional groups are also acceptable.

[0133] 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, and an unsaturated carboxylic acid group. Preferred free radical polymerizable functional groups are a (meth)acryloyl group, an N-vinyl group, a vinyl ether group, an allyl group, and an unsaturated carboxylic acid group.

[0134] [(Meth)acrylic resin (a1)]

[0135] In the present disclosure, the (meth)acrylic resin (a1) is an acrylic copolymer obtained by copolymerizing monomers containing a (meth)acrylic ester monomer, and is a polymer having structural units based on 2 to 20,000 monomers. Preferred examples of (meth)acrylic ester monomers include alkyl (meth)acrylate monomers. When a functional group useful for polymerization / crosslinking reactions is introduced, a (meth)acrylic copolymer obtained by copolymerizing a functional group-containing monomer with a (meth)acrylic ester monomer is preferred.

[0136] Furthermore, the (meth)acrylic resin (a1) of the present disclosure excludes compounds containing two or more urethane bonds in one molecule and compounds having two or more epoxy groups in one molecule.

[0137] The (meth)acrylic acid alkyl ester monomer is a compound obtained by esterifying (meth)acrylic acid and introducing an alkyl group or a cycloalkyl group. 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 thereof include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-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, decyl (meth)acrylate, (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, 4-n-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and the like. Among these, methyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate are particularly preferably used from the viewpoint of the dispersibility of the colorant (B), and methyl (meth)acrylate and n-butyl (meth)acrylate are particularly preferably used.

[0138] The content of the structural unit derived from the alkyl (meth)acrylate monomer is preferably 1 to 100 mass %, more preferably 20 to 99.5 mass %, and even more preferably 80 to 99 mass %, relative to 100 mass % of the (meth)acrylic resin (a1), from the viewpoint of adhesion.

[0139] The (meth)acrylic resin (a1) preferably has a structural unit derived from a functional group-containing monomer and / or an unsaturated bond.

[0140] Examples of functional group-containing monomers include carboxyl group-containing monomers, hydroxyl group-containing monomers, epoxy group-containing monomers, and amino group-containing monomers. The inclusion of functional group-containing monomers improves the cohesive strength of the resin (A), resulting in a tough resin composition layer. Carboxyl group-containing monomers, hydroxyl group-containing monomers, and epoxy group-containing monomers are particularly preferred.

[0141] Examples of carboxyl group-containing monomers include (meth)acrylic acid, β-carboxyethyl (meth)acrylate, p-carboxybenzyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, and isocrotonic acid. Among these, (meth)acrylic acid is preferred from the perspective of adhesion.

[0142] Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. Among these, 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate are more preferred from the viewpoint of adhesion.

[0143] Examples of the amino group-containing monomer include monoalkylamino (meth)acrylates such as monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, and monoethylaminopropyl (meth)acrylate.

[0144] For the purpose of introducing unsaturated bonds into (meth) acrylic resin (a1), epoxy-containing monomers can also be used. As epoxy-containing monomers, for example, can be exemplified: (meth) glycidyl acrylate, (meth) methyl glycidyl acrylate, (meth) 3,4-epoxycyclohexyl methyl ester, (meth) 6-methyl-3,4-epoxycyclohexyl methyl ester. Among these, from the viewpoint of reactivity, it is preferred to include (meth) glycidyl acrylate. Furthermore, it is preferred to react the epoxy group of the epoxy-containing monomer with the carboxyl group of the carboxyl-containing monomer such as (meth) acrylic acid and introduce unsaturated bonds such as (meth) acryloyl into (meth) acrylic resin (a1). At this time, the epoxy group is one or less in one molecule, and it is preferred that no epoxy group remains.

[0145] The total amount of the structural units derived from the functional group-containing monomer is preferably 0.1 to 20% by mass relative to 100% by mass of the (meth)acrylic resin (a1). By setting the amount within this range, the cohesive force can be adjusted.

[0146] The content of the structural unit derived from the carboxyl group-containing monomer is preferably 0.1 to 10% by mass relative to 100% by mass of the (meth)acrylic resin (a1). By being within this range, the adhesion can be improved.

[0147] The content of the structural unit derived from the hydroxyl group-containing monomer is preferably 0.1 to 10% by mass relative to 100% by mass of the (meth)acrylic resin (a1). By being within this range, the adhesion can be improved.

[0148] The (meth)acrylic resin (a1) may also contain structural units derived from other monomers copolymerizable with the (meth)acrylic acid alkyl ester or functional group-containing monomer. For example, monomers having an alkylene oxide group and other vinyl monomers can be mentioned. Examples include methoxyethyl acrylate, methoxydiethylene glycol acrylate, vinyl acetate, vinyl crotonate, styrene, acrylonitrile, and acrylamide. The structural units derived from these other monomers preferably account for 0.1% to 20% by mass of 100% by mass of the (meth)acrylic acid copolymer.

[0149] (Meth) acrylic resin (a1) can be obtained by polymerizing an acrylic monomer mixture. During polymerization, a polymerization initiator can be used as needed. The content of the polymerization initiator is set to, for example, 0.01% to 10% by mass relative to 100% by mass of the monomer mixture. The polymerization method is not limited. For example, polymerization can be carried out by solution polymerization, bulk polymerization, emulsion polymerization, or suspension polymerization. In terms of the ease of polymerization control, solution polymerization is particularly preferred. The solvent used in solution polymerization can be exemplified by: acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, butyl acetate, toluene, xylene, anisole, cyclohexanone, and isopropanol. The polymerization temperature can be set to, for example, about 60°C to 120°C, and the polymerization time can be set to about 2 hours to 12 hours.

[0150] The polymerization initiator is preferably a free radical polymerization initiator. Suitable free radical polymerization initiators include peroxides and azo compounds. Any of the thermal free radical polymerization initiators described below can be used. Specifically, 2,2'-azobisisobutyronitrile (AIBN) is preferred.

[0151] [Urethane resin (a2)]

[0152] In the present disclosure, the urethane resin (a2) refers to a compound containing two or more urethane bonds in one molecule. An example of the urethane resin (a2) is a urethane resin obtained by reacting polyisocyanate with polyol.

[0153] As long as the polyisocyanate has two or more isocyanate groups in one molecule, it is preferably a diisocyanate or a triisocyanate, and more preferably a diisocyanate in terms of the dispersibility of the colorant (B). As the diisocyanate, it can be appropriately selected from known aliphatic diisocyanates such as hexamethylene diisocyanate or known aromatic diisocyanates such as benzene-1,3-diisocyanate. In addition, an isocyanate-terminated prepolymer obtained by reacting a polyol with an excess of polyisocyanate can also be used as an intermediate of the urethane resin.

[0154] The polyol may be any substance having two or more hydroxyl groups in one molecule. From the perspective of the dispersibility of the colorant (B), diols or triols are preferred, with diols being more preferred. The diol may be appropriately selected from known aliphatic diols such as ethylene glycol, or known aromatic diols such as benzene glycol. Prepolymers such as polyether polyols, polyester polyols, and polycarbonate polyols may also be used.

[0155] The urethane resin (a2) may be a polyurethane urea resin having a urea bond. The polyurethane urea resin can be synthesized by reacting, for example, a polyamine with a urethane resin having an isocyanate group at the terminal.

[0156] The polyamine may be any substance having two or more amino groups in one molecule. From the perspective of dispersibility of the colorant (B), diamine or triamine is preferred, and diamine is more preferred. The diamine may be appropriately selected from known aliphatic diamines such as ethylenediamine or known aromatic diamines such as phenylenediamine.

[0157] From the perspective of dispersibility of the colorant (B), 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, or an unsaturated carboxylic acid group, and more preferably has a (meth)acryloyl group. Specifically, a (meth)acryloyl group can be introduced by an addition reaction between the polyol, diisocyanate, or triisocyanate and an acrylate having a hydroxyl group.

[0158] [Epoxy resin (a3)]

[0159] In the present disclosure, epoxy resin (a3) ​​refers to a compound having two or more epoxy groups in one molecule. Epoxy resin (a3) ​​also includes compounds formed by adding functional groups. As the functional group, preferably having a (meth)acryloyl group, N-vinyl group, vinyl ether group, allyl group, unsaturated carboxylic acid group, etc. as a free radical polymerizable functional group, more preferably having a (meth)acryloyl group.

[0160] Regarding the properties of the epoxy resin (a3), the adhesiveness can be optimized by using the epoxy resin (a3) ​​in a liquid form, and the film-forming properties of the resin composition layer can be optimized by using the epoxy resin (a3) ​​in a solid form.

[0161] Epoxy resin (a3) ​​is preferably, for example, a glycidyl ether epoxy resin, a glycidyl amine epoxy resin, a glycidyl ester epoxy resin, a cycloaliphatic (alicyclic) epoxy resin, a bisphenol epoxy resin, a hydrogenated bisphenol epoxy resin, etc. In terms of adhesion, epoxy resin (a3) ​​is more preferably a bisphenol epoxy resin or a high-purity hydrogenated epoxy resin. As a compound having a free radical polymerizable functional group added to one or more epoxy groups as a functional group, bisphenol A diglycidyl ether diacrylate is preferred.

[0162] Examples of the glycidyl ether epoxy resin include cresol novolac epoxy resin, tris(glycidyloxyphenyl)methane, and tetrakis(glycidyloxyphenyl)ethane.

[0163] Examples of the glycidylamine epoxy resin include tetraglycidyldiaminodiphenylmethane and tetraglycidyl-m-xylylenediamine.

[0164] Examples of the glycidyl ester epoxy resin include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate.

[0165] Examples of the cyclic aliphatic (alicyclic) epoxy resin include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl) adipate.

[0166] Examples of the bisphenol epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, and bisphenol AD ​​epoxy resin. From the viewpoint of adhesion, bisphenol A epoxy resin is particularly preferred.

[0167] Examples of the hydrogenated bisphenol epoxy resin include hydrogenated bisphenol A epoxy resin and hydrogenated bisphenol F epoxy resin. From the viewpoint of adhesion, hydrogenated bisphenol A epoxy resin is particularly preferred.

[0168] [Colorant (B)]

[0169] The colorant (B) can be any of an inorganic pigment, an organic pigment, or a dye, and can also be tinted by a mixed system. The hue is not particularly limited, but from the perspective of light-shielding properties, black is preferred. A mixed colorant can be used to obtain black by subtractively mixing multiple pigments. From the perspective of dispersibility, a black pigment is more preferred.

[0170] Examples of black pigments include carbon black, Ketjen black, carbon nanotubes (CNTs), perylene black, titanium black, iron black, aniline black, acetylene black, and chromium iron oxide. Carbon black is preferred from the viewpoint of adhesion.

[0171] As the carbon black used in the present disclosure, known carbon blacks such as channel black, furnace black, thermal black, and lamp black can be used.

[0172] Specific examples of carbon black include Raven 3500, 1180, 1080 Ultra, 1060 Ultra, and 1040 manufactured by Birla Carbon, Toka Black #8300 and #7360SB manufactured by Tokai Carbon, and Orion Engineered Carbon. Carbons' "Special Black 350, 250, 100, 550, 5, 4, 4A, 6", "Nipex 160IQ, 170IQ", "Printex U, V, 140U, 140V, 95, 90, 85, 80, 75, 55, 45, P, 60, L6, L, 300, 30, 3, 35, 25, A, G", "Color Black FW200, FW2, S170", Cabot's "REGAL 400R, 330 R, 250R", "MOGUL E, L", "MONARCH 1300, 280", "MA7, 8, 11, 14, 77, 100, 100R, 100S, 220, 230", "#2650, #2600, #2350, #2300, #1000, #980, #970, #960, #950, #900, #850, #750B, #650B, #52, #47, #45, #45L, #44, #40, #33, #32, #30, #25, #20, #10, #5, #95" manufactured by Mitsubishi Chemical Corporation, etc.

[0173] From the viewpoint of dispersibility, carbon black preferably has a specific surface area of ​​50 m2 based on the Buerter (BET) method. 2 / g~400m 2 / g, a volatile matter of 0.1 wt% to 10 wt%, and a pH value of 2 to 10, more preferably a carbon black having a pH value of 3 to pH 8, and further preferably a carbon black having a pH value of 3 to pH 6.

[0174] The colorant (B) preferably has an average primary particle size (hereinafter referred to as particle size) of 10 nm to 100 nm. By making the particle size 10 nm or more, it is easy to maintain the viscosity of the resin composition at a level suitable for coating. In addition, by making the particle size 100 nm or less, the blackness is improved, showing high light-shielding performance. In addition, when the particle shape of the colorant (B) has an average aspect ratio (major axis length / minor axis length) of 1.5 or more, the particle size is obtained by averaging the major axis length.

[0175] The particle size of the colorant (B) can be determined from the average value of about 20 primary particles observed in an image magnified about 50,000 to 1,000,000 times using a transmission electron microscope (TEM).

[0176] The content of the colorant (B) is preferably 5% to 45% by mass, more preferably 15% to 35% by mass, and even more preferably 20% to 30% by mass, based on the total amount of the light-shielding layer (100% by mass). This is because a content of the colorant (B) of 5% to 45% by mass achieves an excellent level of light-shielding properties.

[0177] From the viewpoint of adjusting the film-forming property and light-shielding property of the resin composition layer, it is preferred that the colorant (B) is dispersed in the resin (A) and used as a dispersion. As a dispersion, the disperser used in the mechanical crushing can be any disperser as long as it is a generally used disperser, for example, a ball mill, a roller mill, a sand mill, a bead mill and a nano mill. Among them, a bead mill is preferably used. As such a disperser, for example, a super mill, a sand mill, an agitator mill, a grain mill, a dyno mill, a pearl mill and a cobol mill (all trade names) can be listed.

[0178] In the present disclosure, from the viewpoint of storage stability of the dispersion, it is preferred to use a dispersant in the dispersion treatment of the colorant (B). In the present disclosure, the dispersant has the function of imparting repulsion between particles to prevent the particles that have been divided by the dispersion treatment from reaggregating.

[0179] As the dispersant, conventionally known compounds can be used, for example, 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.

[0180] Pigment derivative dispersants are compounds having an acidic group, a basic group, a neutral group, etc. in the organic pigment residue. Examples include compounds having acidic substituents such as sulfo, carboxyl, or phosphate groups, and their amine salts, compounds having basic substituents such as sulfonamide, amide, or terminal tertiary amino groups, and compounds having neutral substituents such as phenyl or phthalimide alkyl groups. Examples of organic pigments include phthalocyanine pigments, diketopyrrolopyrrole pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, perylene pigments, thiazine indigo pigments, triazine pigments, benzimidazolone pigments, indole pigments such as benzisoindole, isoindoline pigments, isoindolinone pigments, quinophthalone pigments, naphthol pigments, styrene pigments, metal complex pigments, azo pigments such as azo, disazo, and polyazo. By using these pigment dispersants, it is possible to prevent the colorant (B) contained in the resin composition from aggregating over time and to maintain good light-shielding properties.

[0181] The content of the pigment dispersant (the total content when two or more types are included) is preferably 0.01% to 10% by mass, and more preferably 0.1% to 5% by mass, based on the total amount (100% by mass) of the resin composition layer. By containing 0.01% by mass or more of the pigment dispersant, light-shielding properties are improved, and by containing 10% by mass or less, the viscosity of the black dispersion falls within an appropriate range, and coating suitability is improved.

[0182] [Polymerization initiator (C)]

[0183] In this embodiment, either a photopolymerization initiator or a thermal polymerization initiator can be used. From the perspective of film-forming properties and adhesion of the resin composition layer, a thermal polymerization initiator is preferably used. When either a photopolymerization initiator or a thermal polymerization initiator is used, the resin (A) preferably has one or more free radical polymerizable functional groups as functional groups in one molecule. Examples of free radical polymerizable functional groups include (meth)acryloyl, N-vinyl, vinyl ether, allyl, and unsaturated carboxylic acid groups.

[0184] Examples of the photopolymerization initiator include triazine-based photopolymerization initiators, borate-based photopolymerization initiators, carbazole-based photopolymerization initiators, acetophenone-based photopolymerization initiators, and oxime-ester-based photopolymerization initiators. Acetophenone-based photopolymerization initiators and oxime-ester-based photopolymerization initiators are preferred because they exhibit less yellowing during the heat aging step.

[0185] From the viewpoint of yellowing, the content of the photopolymerization initiator is preferably 0.5 to 10% by mass, more preferably 0.5 to 5% by mass, based on the total amount (100% by mass) of the resin composition layer.

[0186] In the present embodiment, a thermal cationic polymerization initiator or a thermal radical 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.

[0187] Thermal cationic polymerization initiators generate ions through heat. Examples of cation components in thermal cationic polymerization initiators include sulfonium cations, quaternary ammonium cations, and iodonium cations. Examples of anionic components include antimony hexafluoride anions, phosphorus hexafluoride anions, tetrakis(pentafluorophenyl)borate anions, and trifluoromethanesulfonic acid.

[0188] The thermal radical polymerization initiator has a function of generating radicals by heat. Examples of the thermal radical polymerization initiator include organic peroxide polymerization initiators and azo thermal polymerization initiators.

[0189] Examples of the organic peroxide polymerization initiator include dialkyl peroxides such as diacetyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, diisopropylbenzene peroxide, tert-butylisopropylbenzene peroxide, α,α′-bis(tert-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,3-bis(tert-butylperoxyisopropyl)hexane, and (2-ethylhexanoyl)(tert-butyl)peroxide.

[0190] Dipropionyl peroxide, tert-butyl peroxyacetate, tert-butyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, bis(3,5,5-trimethylhexanoyl) peroxide, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, α-isopropylphenyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyneodecanoate, tert-butyl peroxyneoheptanoate, tert-hexyl peroxyvalerate, tert-butyl peroxyvalerate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoic acid Peroxyesters such as tert-butyl peroxyisobutyrate, di-tert-butyl peroxyhexahydroterephthalate, 1,1,3,3-tetramethylbutyl peroxy-3,5,5-trimethylhexanoate, tert-amyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, dibutyl peroxytrimethyladipate, 2,5-dimethyl-2,5-di-ethylhexanoyl peroxyhexane, tert-hexyl peroxy-2-ethylhexanoate, tert-hexyl peroxyisopropyl monocarbonate, tert-butyl peroxylaurate, tert-butyl peroxyisopropyl monocarbonate, and tert-butyl peroxy-2-ethylhexyl monocarbonate;

[0191] Ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, tert-butyl benzoate, and pivaloyl tert-butyl peroxide;

[0192] Peroxyketals such as 2,2-bis(tert-butylperoxy)butane, 2,2-bis(4,4-di-tert-butylperoxycyclohexyl)propane, 1,1-bis(tert-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-hexylperoxy)cyclohexane, and 4,4-bis(tert-butylperoxy)butyl valerate;

[0193] Hydroperoxides such as tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylcyclohexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and p-methane hydroperoxide;

[0194] Diacyl peroxides such as dibenzoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, diisobutyryl peroxide, bis-3,5,5-trimethylhexanol peroxide, m-toluoylbenzoyl peroxide, succinic acid peroxide, and 2,4-dichlorobenzoyl peroxide;

[0195] Peroxydicarbonates such as bis(tert-butylcyclohexyl)peroxydicarbonate, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl)peroxydicarbonate, tert-butylperoxyisopropyl carbonate, di-2-ethylhexyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, tert-amylperoxyisopropyl carbonate, tert-butylperoxy-2-ethylhexyl carbonate, and 6-bis(tert-butylperoxycarboxyoxy)hexane are not limited thereto.

[0196] From the viewpoint of storage stability, dialkyl peroxides are preferred, and di-tert-butyl peroxide is more preferred.

[0197] Examples of the azo thermal polymerization initiator include 2,2'-azobisisobutyronitrile and 2,2'-azobis(2-methylbutyronitrile);

[0198] 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile) and other 2,2'-azobisvaleronitriles;

[0199] 1,1'-azobis(cyclohexane-1-carbonitrile) and other 1,1'-azobis-1-alkanenitrile; 2,2'-azobis(2-hydroxymethylpropionitrile) and other 2,2'-azobispropionitrile;

[0200] 2,2'-azobispropionamides such as 2,2'-azobis(N-butyl-2-methylpropionamide) and 2,2'-azobis(N-cyclohexyl-2-methylpropionamide);

[0201] As well as dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 1-[(1-cyano-1-methylethyl)azo]formamide, etc.

[0202] Examples of azo compounds having a carboxyl group or a hydroxyl group include, but are not limited to, 4,4'-azobis(4-cyanovaleric acid), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide), and 2,2'-azobis(N-(carboxyethyl)-2-methylpropionamidine) tetrahydrate.

[0203] From the viewpoint of storage stability, 2,2'-azobispropionamides are preferred, and 2,2'-azobis(N-butyl-2-methylpropionamide) is more preferred.

[0204] The 10-hour half-life temperature of the thermal radical polymerization initiator is preferably 60°C to 200°C, more preferably 80°C to 180°C, still more preferably 100°C to 150°C, and particularly preferably 105°C to 130°C. By setting the temperature at 60°C or higher, the storage stability of the resin composition layer can be improved, while by setting the temperature at 200°C or lower, the heat aging step of the sealant layer can be shortened.

[0205] The 10-hour half-life temperature is the temperature at which the thermal polymerization initiator's free radicals are reduced to half their initial value after 10 hours through thermal decomposition. Specifically, a thermal polymerization initiator solution is prepared using a solvent inert to the free radicals of the thermal polymerization initiator and sealed in a nitrogen-purged glass tube. This solution is then immersed in a constant temperature chamber set at a predetermined temperature for 10 hours to allow thermal decomposition, and the amount of remaining thermal polymerization initiator is measured. This series of steps is repeated at several temperatures, and the resulting straight line is plotted to determine the half-life.

[0206] The content of the thermal radical polymerization initiator is preferably 0.01% to 20% by mass, more preferably 0.05% to 10% by mass, and even more preferably 0.1% to 5% by mass, based on the total amount of the resin composition layer (100% by mass). By setting the content to such a level, the adhesion can be appropriately adjusted.

[0207] [Other ingredients]

[0208] The resin composition layer of the present disclosure may contain other components within the scope not impairing the purpose of the present disclosure. For example, crosslinking agents, monomers, inorganic fillers, surface conditioning additives, hardening accelerators, hardening retarders, softeners, antistatic agents, lubricants, anti-blocking agents, adhesion improvers, etc. may be added.

[0209] From the viewpoint of controlling the film-forming properties of the resin composition layer, it is preferred to contain a cross-linking agent and a monomer.

[0210] Examples of the inorganic filler include inorganic compounds such as silica, alumina, magnesium hydroxide, barium sulfate, calcium carbonate, titanium oxide, zinc oxide, antimony trioxide, magnesium oxide, zirconium oxide, talc, kaolinite, mica, basic magnesium carbonate, sericite, montmorillonite, bentonite, boron nitride, aluminum nitride, and titanium nitride. Among these, titanium oxide, titanium nitride, silica, and zirconium oxide are preferred from the perspective of coating film resistance to scratches.

[0211] The resin composition layer of the present disclosure may contain a curing accelerator to adjust the crosslinking rate. The curing accelerator is not particularly limited and can be selected as appropriate. Specific examples of curing accelerators include amine-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators.

[0212] [Crosslinking agent]

[0213] The resin composition layer of the present disclosure may also contain a crosslinking agent. The crosslinking agent undergoes a crosslinking reaction with the reactive functional groups of the resin (A) during hot pressing or heat aging in the pressing process, thereby increasing the cohesive force of the resin composition layer and improving the adhesion. The crosslinking agent has a plurality of functional groups that can react with the functional groups of the resin (A). Examples of the crosslinking agent include: silane coupling agents, anhydride group-containing compounds, imidazole compounds, isocyanate compounds, aziridine compounds, amine compounds and other known compounds. From the perspective of adjusting the loss tangent (tan δ) of the resin composition layer, silane coupling agents, aziridine compounds and imidazole compounds are preferred.

[0214] Examples of the aziridine compound include trimethylolpropane tris[3-(aziridin-1-yl)propionate], tetramethylolmethane-tris-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.

[0215] Examples of the imidazole compound 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 trimellitic acid, 2,4-diamino-6-[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. Further examples include compounds having improved storage stability, such as those obtained by encapsulating the imidazole compound in microcapsules.

[0216] The isocyanate compound is an isocyanate having two or more isocyanate groups, and isocyanate monomers such as aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates, as well as biuret forms, urate forms, and adducts thereof are preferred.

[0217] From the viewpoint of forming sufficient cross-linked structure, isocyanate compound is preferably a trifunctional isocyanate compound. Isocyanate compound is more preferably an adduct and a urate body of the reaction product of an isocyanate monomer and a trifunctional compound containing low molecular active hydrogen. Isocyanate compound is preferably a trimethylolpropane adduct of hexamethylene diisocyanate, a urate body of hexamethylene diisocyanate, a trimethylolpropane adduct of toluene diisocyanate, a urate body of toluene diisocyanate, a trimethylolpropane adduct of isophorone diisocyanate, a urate body of isophorone diisocyanate, more preferably a trimethylolpropane adduct of hexamethylene diisocyanate, a trimethylolpropane adduct of toluene diisocyanate, a trimethylolpropane adduct of isophorone diisocyanate.

[0218] The silane coupling agent is a compound in which a hydrolyzable group such as a methoxy group or an ethoxy group and a functional group such as an epoxy group are bonded to a Si atom via an alkylene group.

[0219] Examples of the silane coupling agent include alkoxysilane compounds having a (meth)acryloyloxy group, such as 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropyltripropoxysilane, 3-(meth)acryloyloxypropyltributoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, and 3-(meth)acryloyloxypropylmethyldiethoxysilane.

[0220] Alkoxysilane compounds having a vinyl group, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane, and vinylmethyldiethoxysilane;

[0221] 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;

[0222] Alkoxysilane compounds having a mercapto group, such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane;

[0223] 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;

[0224] Tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane;

[0225] 3-Chloropropyltrimethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, styryltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylene)propylamine, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, hexamethyldisilazane, silicone resins having an alkoxysilyl group in the molecule, etc.

[0226] From the viewpoint of adhesion, an alkoxysilane compound is preferred, and 3-glycidoxypropyltrimethoxysilane is more preferred.

[0227] The content of the crosslinking agent 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 of the resin composition layer (100% by mass). By setting the content to this level, the adhesion can be appropriately adjusted.

[0228] [monomer]

[0229] The monomer used in the resin composition of the present invention refers to a compound having a free radical polymerizable functional group added to the resin composition. Examples of free radical polymerizable functional groups include: (meth)acryloyl, N-vinyl, vinyl ether, allyl, unsaturated carboxylic acid groups, and the like. In addition, the monomer may be a monofunctional monomer or a polyfunctional monomer. In addition, the term "monofunctional" in this specification refers to a compound having only one free radical polymerizable functional group in one molecule, and "difunctional" and "trifunctional" refer to compounds having two and three free radical polymerizable functional groups in one molecule, respectively. In addition, in this specification, compounds having two or more functional groups are collectively referred to as "polyfunctional". By containing monomers, the film-forming properties of the resin composition layer are adjusted, and the adhesion becomes good.

[0230] Specific examples of the monomer include, but are not limited to, a monofunctional (meth)acrylate monomer having one (meth)acryloyl group in the molecule, a monofunctional vinyl monomer having one N-vinyl group in the molecule, a difunctional (meth)acrylate monomer having two (meth)acryloyl groups in the molecule, a difunctional (meth)acrylate monomer having one (meth)acryloyl group and one allyl group in the molecule, a trifunctional (meth)acrylate monomer having three (meth)acryloyl groups in the molecule, a tetrafunctional (meth)acrylate monomer having four acryloyl groups in the molecule, a pentafunctional (meth)acrylate monomer having five (meth)acryloyl groups in the molecule, and a hexafunctional (meth)acrylate monomer having six (meth)acryloyl groups in the molecule.

[0231] Among these, from the viewpoint of adhesion, it is preferred to contain 3-((meth)acryloyloxy)propyltrimethoxysilane and 3-((meth)acryloyloxy)propyltriethoxysilane.

[0232] The monomer content is preferably 0.01% to 30% by mass, more preferably 0.05% to 20% by mass, and even more preferably 0.1% to 15% by mass, based on the total amount of the resin composition layer (100% by mass). By setting such a content, the adhesion can be appropriately adjusted.

[0233] [Example]

[0234] Hereinafter, the present disclosure will be described in detail by way of Examples and Comparative Examples, but the present disclosure is not particularly limited to the Examples. In the following descriptions, "parts" and "%" represent "parts by mass" and "% by mass," respectively, unless otherwise specified.

[0235] (a) Determination method

[0236] The numerical values ​​obtained in this example are obtained by the following method.

[0237] [Weight average molecular weight (Mw)]

[0238] The weight average molecular weight (Mw) was determined by using a GPC "LC-GPC System" manufactured by Shimadzu Corporation and converting polystyrene having a known molecular weight as a standard substance.

[0239] Device Name: Shimadzu Corporation, LC-GPC System "Prominence"

[0240] Pipe string: Four GMHXL pipes manufactured by Tosoh Corporation and one HXL-H pipe manufactured by Tosoh Corporation are connected.

[0241] Mobile phase solvent: tetrahydrofuran

[0242] Flow rate: 1.0 mL / min

[0243] Column temperature: 40°C

[0244] [Solid content]

[0245] Measure the mass of the aluminum cup (W0) using a precision balance. Next, place approximately 1g of sample in the aluminum cup and measure the mass of the sample (W1) with the aluminum cup using a precision balance. Heat the sample in the aluminum cup in an oven at 150°C for 120 minutes, remove it from the oven, and return it to room temperature. Measure the remaining mass (W2) of the heated sample (W0) with the aluminum cup using a precision balance. Calculate the solids content using the formula (W2 - W0) / (W1 - W0) × 100 (%).

[0246] [Thickness Tt of Sealing Sheet, Thickness Ta of Resin Composition Layer, Thickness Tl of First Film, Thickness Th of Second Film]

[0247] 10 equally spaced locations are determined within the range from the end in the width direction to the other end of a sealing sheet cut into a size of 10 cm × 10 cm, and the thickness of the 10 locations is measured, and the average value is set as the thickness Tt of the sealing sheet. Next, the first film is peeled off from the sealing sheet, and the thickness of the first film after peeling off at 10 locations corresponding to the same position as the position is measured. The average value is set as Tl. Thereafter, the second film is peeled off from the resin composition layer, and the thickness of the second film after peeling off at 10 locations corresponding to the same position as the position is measured. The average value is set as Th. The thickness Ta of the resin composition layer is calculated by the formula Ta=Tt-Tl-Th. In addition, the thickness is measured using MH-15M (manufactured by Nikon).

[0248] [Loss tangent (tan δ) of resin composition layer]

[0249] A sealing sheet prepared so that the thickness Ta of the resin composition layer was 50 μm was cut into 0.5 cm × 2 cm dimensions, and the first and second films were peeled off. The resulting resin composition layer was subjected to dynamic viscoelasticity measurement using a dynamic viscoelasticity measuring apparatus DVA-200 / L2 (manufactured by IT Measurement & Control Co., Ltd.) at a frequency of 10 Hz, a measurement temperature range of -50°C to 150°C, a heating rate of 5°C / min, and a tensile mode. The loss tangent (tan δ) was plotted. From the resulting graph, the maximum value of the loss tangent (tan δ) (tan δ maximum), the loss tangent at 40°C (tan δ 40°C), and the peak temperature of the loss tangent (tan δ peak temperature) were read.

[0250] [Young's modulus of the second film]

[0251] For the second film, the stress-strain curve was measured using a tensile testing machine "EZ Tester" (manufactured by Shimadzu Corporation) at 23°C, a relative humidity of 50%, a tensile speed of 50 mm / min, and a line spacing of 25 mm. The linear regression (slope) in the region where the strain (elongation) was 0.1% to 0.3% was taken as the Young's modulus.

[0252] [Pencil hardness]

[0253] The first film of the sealing sheet was peeled off, and the exposed resin composition layer surface was measured according to the test method of Japanese Industrial Standards (JIS) K 5600-5-4. The pencil used was a pencil for pencil hardness test (manufactured by Mitsubishi Pencil Co., Ltd.).

[0254] (b) Preparation of Resin (A) Solution

[0255] [Production Example of (Meth)Acrylic Resin (a1) (A-1) Solution]

[0256] A reaction vessel (hereinafter referred to as the "reaction vessel") equipped with a stirrer, a thermometer, a reflux cooling tube, a dripping device, and a nitrogen inlet tube was charged with 80 parts of ethyl acetate, 13 parts of n-butyl acrylate, 85 parts of n-butyl methacrylate, 2 parts of methacrylic acid, and 0.1 part of 2,2'-azobisisobutyronitrile as an initiator. The atmosphere in the reaction vessel was purged with nitrogen. The reaction was then heated to 65°C while stirring under a nitrogen atmosphere to initiate the reaction. The reaction solution was then allowed to react at 65°C for 4 hours. After the reaction was completed, the solution was cooled and diluted with ethyl acetate to obtain a solution of (meth)acrylic resin (a1) (A-1) having a weight average molecular weight (Mw): 100,000 and a solids content: 25%.

[0257] [Production Example of Solution of (Meth)Acrylic Resin (a1) (A-2)]

[0258] (Meth)acrylic resin (a1) (A-2) was produced by the same method as for (meth)acrylic resin (a1) (A-1), except that the monomer amounts were changed to 20 parts of n-butyl acrylate, 70 parts of n-butyl methacrylate, 5 parts of methacrylic acid, and glycidyl methacrylate. Furthermore, the weight average molecular weight (Mw) was 130,000, and the solid content was 25%.

[0259] [Production Example of Solution of (Meth)Acrylic Resin (a1) (A-3)]

[0260] KRM8912 (manufactured by Daicel-Allnex) was diluted with ethyl acetate to produce a (meth)acrylic resin (a1) (A-3). The weight average molecular weight (Mw) was 1,000, and the solid content was 25%.

[0261] [Production Example of Urethane Resin (a2) (A-4) Solution]

[0262] Art Resin UN-9000PEP (manufactured by Negami Industries) was diluted with ethyl acetate to produce a urethane resin (a2) (A-4). The weight average molecular weight (Mw) was 5,000, and the solid content was 25%.

[0263] [Production Example of Epoxy Resin (a3) ​​(A-5) Solution]

[0264] Epoxy resin (a3) ​​(A-5) was prepared by diluting jER256B40 (manufactured by Mitsubishi Chemical Corporation) with ethyl acetate. The weight average molecular weight (Mw) was 45,000, and the solid content was 25%.

[0265] (c) Production of a dispersion of a colorant (B)

[0266] [Production Example of Dispersion (D-1) of Colorant (B)]

[0267] 800 parts of a solution of the resin (A-1), 800 parts of carbon black MA100 (manufactured by Mitsubishi Chemical Corporation) as a colorant (B-1), and 400 parts of methyl ethyl ketone as a solvent were mixed and pre-dispersed using a disperser. The mixture was then fully dispersed for 2 hours using a 0.6 L Dynamill filled with 1800 g of zirconia beads having a diameter of 1.0 mm to prepare a dispersion (D-1).

[0268] [Production Example of Dispersion (D-2) of Colorant (B)]

[0269] 800 parts of a solution of resin (A-2), 800 parts of carbon black MA100 (manufactured by Mitsubishi Chemical Corporation) as a colorant (B-1), 400 parts of methyl ethyl ketone as a solvent, and 2 parts of Solsperse 5000 (manufactured by Lubrizol) as a pigment derivative dispersant were mixed and pre-dispersed using a disperser. Then, a full dispersion was carried out for 2 hours using a 0.6 L Dyno mill filled with 1800 g of zirconia beads with a diameter of 1.0 mm to prepare a dispersion (D-2).

[0270] [Production Example of Dispersion (D-3) of Colorant (B)]

[0271] 800 parts of a solution of resin (A-1), 800 parts of Black 6340 (manufactured by Asahi Chemical Industries, Ltd.) as a metal oxide pigment as a colorant (B-2), and 400 parts of methyl ethyl ketone as a solvent were mixed and pre-dispersed using a disperser. The mixture was then fully dispersed for 2 hours using a 0.6 L Dynamill filled with 1800 g of zirconia beads having a diameter of 1.0 mm to prepare a dispersion (D-3).

[0272] (d) Production of resin composition

[0273] [Production Example of Resin Composition of Example 1]

[0274] Dispersion (D-1): 60 parts (24 parts colorant (B-1), 6 parts resin (A-1), 30 parts solvent), 276 parts resin (A-1) solution (69 parts resin (A-1), 207 parts solvent), 1 part aziridine compound Chemitite PZ-33 (manufactured by Nippon Catalyst Co., Ltd.), and 63 parts toluene as a solvent were added sequentially while stirring using a disperser and stirred until fully homogenized. The mixture was then filtered through a 10 μm pore size membrane filter to remove coarse foreign matter that could cause uneven coating, resulting in a resin composition with a non-volatile content of 33%. Other components are expressed as solids.

[0275] (e) Manufacturing of sealing sheet

[0276] [Manufacturing Example of Sealing Sheet of Example 1]

[0277] The resin composition was applied to a release layer of SP-PET-O3-BU (Mitsui Chemicals Tohcello) as the second film (H-2) with a thickness of 50 μm so that the thickness after drying was 20 μm, and dried in a hot air oven at 100°C for 3 minutes to form a resin composition layer. Next, the release layer side of SP-PET-O1-T (Mitsui Chemicals Tohcello) as the first film (L-2) with a thickness of 25 μm was attached to the exposed resin composition layer and aged at 0°C for 7 days to obtain a sealing sheet of Example 1 laminated in the order of first film / resin composition layer / second film. In addition, the tan δ peak temperature was 29°C.

[0278] (f) Evaluation method of sealing sheet

[0279] [Embeddability]

[0280] Prepare a test substrate that simulates the concave and convex patterns of a micro-LED substrate (a plate with a concave portion of 200 μm width, a convex portion of 5 μm height, and a convex portion of 200 μm width formed on one surface of a 25 mm × 25 mm glass plate). Figure 3 middle.

[0281] The sealing sheet is cut into a size of 30 mm × 30 mm, the first film is peeled off to expose the resin composition layer, and the resin composition layer is placed on the surface of the test substrate having a concave-convex portion. Thereafter, TPX (Opulent X-44B, manufactured by Mitsui Chemicals Tohcello) with a thickness of 50 μm as a buffer material and a vinyl chloride film (Celeb T, manufactured by Okamoto) with a thickness of 2.0 mm are sequentially stacked on the second film, and then cardboard is stacked to prevent sticking. The laminate comprising a glass substrate / resin composition layer / second film / buffer material (TPX / vinyl chloride film) / cardboard is pressed from above to the substrate surface under the conditions of 5 MPa and 100 ° C for 20 minutes, so that the resin composition layer is filled into the concave portion of the test substrate, thereby forming a sealing layer. After pressing, the buffer material and the cardboard are peeled off.

[0282] Use a cutter to roughly remove the sealing layer extending from the side of the obtained test substrate with a sealing layer, and then file it to remove the sealing layer remaining on the side of the test substrate with a sealing layer, exposing the side of the test substrate so that the concave and convex parts can be observed. The embedding property is evaluated by observing the concave parts of the test substrate at any 15 locations using a microscope. The groove is considered to be embedded when the maximum gap between the sealing layer and the test substrate in the concave part of the test substrate is less than 1μm. The evaluation criteria are as follows.

[0283] A: There are more than 14 buried grooves

[0284] B: The number of buried grooves is less than 13 and more than 11

[0285] C: The number of buried grooves is less than 10 and more than 8

[0286] D: There are less than 7 buried grooves

[0287] [Die displacement]

[0288] LEDs (SMD, 0402, 1.0 mm x 0.5 mm) with wiring were placed on a general-purpose glass epoxy substrate (32 mm wide x 53 mm deep x 1.2 mm thick, 2.54 mm pitch). Current flow to the LEDs was confirmed to prepare a test substrate.

[0289] The sealing sheet is cut into a size of 60 mm × 60 mm, and the first film is peeled off to expose the resin composition layer, and the resin composition layer is placed in a manner that is in contact with the LED arranged on the test substrate. Subsequently, TPX (Opulent X-44B, manufactured by Mitsui Chemicals Tohcello) with a thickness of 50 μm and a vinyl chloride film (Celeb T, manufactured by Okamoto) with a thickness of 2.0 mm are sequentially stacked on the second film as a buffer material, and then cardboard is stacked to prevent sticking. The laminate becomes a structure of glass substrate / resin composition layer / second film / buffer material (TPX / vinyl chloride film) / cardboard. Then, the substrate surface is pressed from the top of the test piece under the conditions of 5 MPa and 100 ° C for 20 minutes to fill the resin composition layer around the LED, thereby forming a sealing layer. After pressing, the buffer material and the cardboard are peeled off. The power supply of the LED is confirmed on the obtained pressed test piece using a power tester. LEDs that were not energized were considered to have wiring misalignment due to die displacement during embedding, and were evaluated as having wiring misalignment. This evaluation was conducted 10 times, and the evaluation criteria were as follows.

[0290] A: There is wiring deviation 0 to 1 time

[0291] B: There are 2 wiring deviations

[0292] C: There are 3 wiring deviations

[0293] D: There are 4 to 10 wiring deviations

[0294] [Light blocking properties]

[0295] The first and second films of the sealing sheet were peeled off to expose the resin composition layer. The optical density (visual quality) of the resin composition layer was measured using an optical densitometer (361T desktop transmission densitometer, manufactured by X-Rite). The evaluation criteria were as follows.

[0296] A: Optical density of 6 or more

[0297] B: Optical density is 4 or more and less than 6

[0298] C: Optical density less than 4

[0299] [Tightness]

[0300] Prepare a sealing sheet obtained by cutting the sealing sheet into 25mm×100mm, peel off the first film to expose the resin composition layer, and place it on a glass plate (25mm×100mm×1.1mm, blue plate glass, manufactured by Kawamura Jiuzang Shoten Co., Ltd.). Thereafter, TPX (Opulent X-44B, manufactured by Mitsui Chemicals Tohcello) with a thickness of 50μm as a buffer material and a vinyl chloride film (Celeb T, manufactured by Okamoto) with a thickness of 2.0mm are sequentially laminated on the second film, and then cardboard is laminated to prevent sticking. The laminate comprising a glass plate / resin composition layer / second film / buffer material (TPX / vinyl chloride film) / cardboard is pressed from above to the substrate surface under the conditions of 5MPa and 100°C for 20 minutes, and the glass plate and the resin composition layer are pressed to form a sealing layer on the glass plate. After pressing, the buffer material, cardboard, and second film are peeled off. A test piece including a glass plate and a sealing layer was left to stand at 180° C. for 120 minutes to prepare a test piece in which the glass plate and the sealing layer were in close contact with each other.

[0301] According to JIS K 5600-5-6 (cross-cut method), a 1 mm square grid pattern (25 grids) was made on the sealing layer of the test piece using a cross-cut guide and a cutter. An adhesive tape (CT1835, manufactured by Nichiban) was attached to the grid-cut portion, adhering tightly to the sealing layer. Within 5 minutes of attachment, the adhesive tape was peeled off at an angle close to 60° for 0.5 to 1.0 seconds. The condition of the peeled sealing layer was observed to evaluate the adhesion. The evaluation criteria are as follows. In addition, the case where the sealing layer peeled off from the glass plate when peeling the second film was set as a C evaluation.

[0302] A: The number of peeled squares is 0

[0303] B: 1 to 2 peeling squares

[0304] C: The number of peeling grids is 3 to 25

[0305] In any of the above evaluations, the best evaluation is designated A, the second best evaluation is designated B, the next best evaluation is designated C, and the evaluation that does not reach the target performance is designated D. Furthermore, it is consistent with the present disclosure that all performance evaluations are designated A to C.

[0306] [Example 2 to Example 25], [Comparative Example 1 to Comparative Example 8]

[0307] A sealing sheet was prepared and evaluated in the same manner as in Example 1 except that the contents and thicknesses Ta were changed to those shown in Tables 1 to 3. Any other components were also added simultaneously.

[0308] In Tables 1 to 3, the amounts of resin (A), colorant (B), polymerization initiator (C), and other components are calculated on a solids basis, and blank columns indicate that no components were added. The tan δ peak temperature of Example 2 was 22°C.

[0309] The abbreviations in the table are as follows.

[0310] C-1: Di-tert-butyl peroxide (Perbutyl D, manufactured by NOF Corporation)

[0311] C-2: 2,2'-azobis(N-butyl-2-methylpropionamide) (VAm-110, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0312] O-1: Aziridine compound as a crosslinking agent (Chemitite PZ-33, manufactured by Nippon Catalyst Co., Ltd.)

[0313] O-2: Silane coupling agent as a crosslinking agent (KBE-403, manufactured by Shin-Etsu Silicones Co., Ltd.)

[0314] O-3: 2-phenylimidazole as a crosslinking agent (Curezol 2PZ, manufactured by Shikoku Chemical Industry Co., Ltd.)

[0315] O-4: Ethylene oxide (EO)-modified (3) trimethylolpropane triacrylate (Miramer M3130, manufactured by MIWON, trifunctional) as a monomer

[0316] O-5: 3-methacryloxypropyltrimethoxysilane (KBE-503, manufactured by Shin-Etsu Silicones Co., Ltd., monofunctional) as a monomer

[0317] L-1: First film with a thickness of 10 μm (matt film (type M3), manufactured by IM Co., Ltd., Sq: 1.5 μm)

[0318] L-2: First film with a thickness of 25 μm (SP-PET-O1-T, manufactured by Mitsui Chemicals Tohcello, Sq: 0.2 μm)

[0319] L-3: First film with a thickness of 50 μm (matt film (type M3), manufactured by IM Co., Ltd., Sq: 1.5 μm)

[0320] L-4: First film with a thickness of 100 μm (SP-PET-O1-T, manufactured by Mitsui Chemicals Tohcello, Sq: 0.2 μm)

[0321] H-1: Second film with a thickness of 12 μm (Torayfan High-End OPP film, manufactured by Toray Industries, Ltd., Young's modulus: 3.5 GPa)

[0322] H-2: Second film with a thickness of 50 μm (SP-PET-O3-BU, manufactured by Mitsui Chemicals Tohcello, Young's modulus: 4.7 GPa)

[0323] H-3: Second film with a thickness of 100 μm (release film PE, manufactured by IM Co., Ltd., Young's modulus: 1.1 GPa)

[0324] H-4: Second film with a thickness of 188 μm (Cosmo Peel E7004, manufactured by Toyobo Co., Ltd., Young's modulus: 5.9 GPa)

[0325] H-5: Second film with a thickness of 6 μm (Lumirror F53, manufactured by Toray Industries, Ltd., Young's modulus: 4.4 GPa)

[0326] H-6: Second film with a thickness of 250 μm (Lumirror T60, manufactured by Toray Industries, Ltd., Young's modulus: 4.8 GPa)

[0327]

[0328]

[0329]

[0330] In the present disclosure, in the case of a sealing sheet in which the thickness Ta of the resin composition layer is outside the range of 2 μm to 100 μm and Ta and the thickness Th of the second film do not satisfy the relationship of 0.1≦Ta / Th≦2, as shown in Comparative Examples 1 and 2, it is found that there are problems with embedding properties and die shifting properties.

[0331] In addition, in the case of a sealing sheet having a second film thickness Th outside the range of 12 μm to 188 μm and not satisfying the relationship of 0.1≦Ta / Th≦2, as shown in Comparative Examples 3 and 4, problems with embedding properties and die shifting properties are found.

[0332] In addition, in the case of a sealing sheet that does not satisfy the relationship of 0.1≦Ta / Th≦2, as shown in Comparative Examples 5 and 6, it is found that there are problems in one or more of embedding properties and die shifting properties.

[0333] In addition, when the maximum value of the loss tangent (tanδ maximum) of the resin composition layer obtained by dynamic viscoelasticity measurement in the range of -50°C to 80°C is outside the range of 0.6 to 2.2, as shown in Comparative Examples 7 and 8, there is a problem with either embedding property or die displacement property.

[0334] As shown in Table 3, the sealing sheets of Comparative Examples 1 to 8 cannot satisfy both embedding properties and die shifting properties at a well-balanced and high level.

[0335] In contrast, Examples 1 to 25 demonstrate excellent embedding properties and excellent die shift resistance, as shown in Tables 1 to 3. Furthermore, the sealing sheet of the present disclosure exhibits excellent light-blocking and adhesion properties, thereby preventing light leakage due to insufficient light-blocking power or light leakage from gaps in the sealing layer due to poor adhesion, thereby ensuring display visibility and providing excellent light controllability.

Claims

1. A sealing sheet for sealing a micro-light emitting diode used in a display that uses the micro-light emitting diode as a light source. The sealing sheet is sequentially provided with a first film, a resin composition layer and a second film, The first film has a release layer on a surface facing the resin composition layer. The thickness Ta of the resin composition layer is 2 μm to 100 μm, The thickness Th of the second film is 12 μm to 188 μm, Ta and Th satisfy formula (1), The resin composition layer comprises a resin (A) and a colorant (B), The resin (A) comprises at least one selected from the group consisting of acrylic resin (a1), urethane resin (a2) and epoxy resin (a3), The colorant (B) comprises carbon black, The maximum value of the loss tangent of the resin composition layer obtained by dynamic viscoelasticity measurement in the range of -50°C to 80°C is 0.6 to 2.2, Formula (1): 0.1≦Ta / Th≦2.

2. The sealing sheet according to claim 1, wherein The Young's modulus of the second film is 1 GPa to 6 GPa.

3. The sealing sheet according to claim 1, wherein The ratio of the root mean square height Sq of the surface of the first film in contact with the resin composition layer as defined in ISO 25178 to the thickness Ta of the resin composition layer is 30% or less. The sealing sheet according to claim 1 , wherein: The pencil hardness of the resin composition layer is 5B to 2H.

5. The sealing sheet according to any one of claims 1 to 4, wherein The resin composition layer contains a polymerization initiator (C).

6. A method for manufacturing a display using a micro-LED as a light source, comprising the following steps (1) to (6): (1) a step of preparing the sealing sheet according to any one of claims 1 to 4, wherein a first film, a resin composition layer for forming a sealing layer, and a second film are sequentially arranged; (2) a step of preparing a sealing object in which a plurality of micro light-emitting diodes are arranged at intervals on one surface of a substrate; (3) a step of peeling the first film from the sealing sheet to expose the resin composition layer for forming the sealing layer; (4) a step of placing the exposed resin composition layer for forming a sealing layer so as to cover the plurality of micro light-emitting diodes; (5) a step of flowing a resin composition layer for forming a sealing layer and filling the space between the plurality of micro light-emitting diodes; (6) A step of peeling off the second film.

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