Release film integrated sealing material for self-luminous display body

Abstract

To provide novel technical means capable of avoiding a loss of smoothness on a surface of a sealing material generated along with a use of a release film in a heat lamination step at a manufacturing process of a self-luminous type display body, and a deterioration in quality of the self-luminous type display body due to the loss of smoothness.SOLUTION: A release film integrated type sealing material 1 is a multilayer film including a sealing film 111 and a release film 121 laminated together. In the release film 121, a surface roughness Rz of a detachment face 122 being a surface of an interface side with the sealing film 111 is 80 nm to 500 nm, and an adhesion strength at an interface between the sealing film 111 and the release film 121 measured with a prescribed adhesion test is 0.3 N / 15 mm to 3.0 N / 15 mm.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a sealing material for a self-luminous display. Specifically, this sealing material is a release film integrated type sealing material in which a release film is integrated in advance during film formation, and is a sealing material capable of improving the quality stability and productivity of an LED module for a self-luminous display.

Background Art

[0002] As a next-generation display device replacing various liquid crystal display devices, the development of self-luminous displays typified by micro LED TVs is in progress (see Patent Document 1). Usually, these self-luminous displays are formed by laminating a sealing film for protecting a light-emitting element on the surface of the light-emitting surface side of a light-emitting module in which a light-emitting element such as an LED element is mounted on a wiring substrate, and further laminating a display surface panel such as various optical films and transparent protective glass (see Patent Documents 2 and 3).

[0003] The sealing material for a self-luminous display constituting the LED module is required to be excellent in adhesion to, for example, a glass epoxy resin or a glass plate constituting a wiring substrate such as an LED module. As an example of a sealing film having such adhesion, Patent Document 2 discloses a sealing material containing polyethylene, and Patent Document 3 discloses a sealing material containing acid-modified polyethylene having excellent glass adhesion.

[0004] By the way, the LED module is manufactured by a thermal lamination process in which a laminate formed by laminating a light-emitting module and a sealing film is placed on a heating plate and integrally formed by thermocompression bonding. In this process, in order to ensure sufficient peelability after the completion of the above process between the sealing film having excellent adhesion and the above heating plate, it is necessary to interpose various release films made of a polyester resin or the like between the sealing film and the heating plate when performing the above thermocompression bonding.

[0005] Conventionally, as such a release film, for example, various release films made of high-performance fluorine-based resins such as PTFE (polytetrafluoroethylene) and ETFE (ethylene tetrafluoride), or polyester-based resins such as PET (polyethylene terephthalate) have been used (see Patent Document 4).

[0006] However, when performing the above heat lamination process with these release films interposed, due to deformation of the release film itself accompanying heating, or entry of fine foreign matter into the gap between the release film and the sealing film, etc., the smoothness of the surface of the sealing material after film formation may be impaired. The loss of the smoothness of the surface of the sealing material causes a decrease in the optical properties and long-term durability of the self-luminous display. At the production site of LED modules, new technical means for avoiding such quality degradation associated with the use of such release films have been demanded.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention has been made in view of the above circumstances, and in the heat lamination process performed in the manufacturing process of a self-luminous display, it is an object to provide new technical means capable of avoiding the loss of smoothness of the surface of the sealing material that occurs with the use of a release film and the resulting quality degradation of the self-luminous display.

Means for Solving the Problems

[0009] As a result of intensive research, the present inventors have found that the above problems can be solved by using a release film integrated type sealing material in which a release film is integrated in advance during film formation for a self-luminous display body, and have completed the present invention. Specifically, the present invention provides the following.

[0010] (1) A sealing material for a self-luminous display body, which is a multilayer film in which a sealing film and a release film are laminated, the sealing film being based on an olefin resin, and the release film having a melting point of 220°C or higher and 270°C or lower, and the adhesion strength at the interface between the sealing film and the release film measured by the following adhesion test being 0.3 N / 15 mm or higher and 3.0 N / 15 mm or lower. A release film integrated type sealing material. Adhesion test: In a release film integrated type sealing material cut into a width of 15 mm, the release film adhered to the sealing film is subjected to a vertical peeling (50 mm / min) test using a peeling tester (Tensilon universal testing machine RTF-1150-H), and the adhesion strength at the interface between the two films is measured.

[0011] In the invention of (1), the sealing material for a self-luminous display body is a multilayer film in which a sealing film and a release film are integrated in advance. In addition, the lower limit of the adhesion strength between the two films is set to be equal to or higher than the strength that can maintain the handleability as an integrated multilayer film at a preferable level, and the upper limit is set to be equal to or lower than the strength that can maintain good releasability. According to such a release film integrated type sealing material, it is possible to avoid the loss of the smoothness of the surface of the sealing material that occurred with the use of the release film during the heat lamination process performed in the manufacturing process of the self-luminous display body.

[0012] (2) The release film integrated type sealing material according to (1), wherein the release film has a wetting index according to JIS K 6768 on the surface of the peeling surface, which is the surface on the interface side with the sealing film, of 25 Dyne or higher and 40 Dyne or lower.

[0013] In the invention of (2), in the release film integrated sealing material described in (1), on the premise that the release film and the sealing film are integrated, the wetting index of the release surface of the release film disposed on the interface side of the two layers is adjusted to a specific range different from that of a conventional single release film. Thereby, the quality stability of the release film integrated sealing material that satisfies the above requirements regarding the adhesion strength between the films in the invention of (1) can be easily maintained at a good level.

[0014] (3) The release film integrated sealing material according to (1) or (2), wherein the surface roughness Rz of the release surface, which is the surface on the interface side with the sealing film, of the release film is 80 nm or more and 500 nm or less.

[0015] In the invention of (3), in the release film integrated sealing material described in (1) or (2), on the premise that the release film and the sealing film are integrated, the surface roughness Rz of the release surface of the release film disposed on the interface side of the two layers is adjusted to a range of 80 nm or more and 500 nm or less. Thereby, in the process of laminating and integrating the resin film constituting the sealing film and the resin film constituting the release film in roll-to-roll production equipment, it is possible to reduce the occurrence of wrinkles and meandering of the film running between the rolls, which is likely to occur.

[0016] (4) The release film integrated sealing material according to any one of (1) to (3), wherein the release film is a polyethylene terephthalate resin film, and the polyethylene terephthalate resin film is a surface untreated polyethylene terephthalate resin film on which no surface treatment for adjusting adhesion and release properties is performed on the release surface, which is the surface on the interface side with the sealing film.

[0017] In the invention of (4), the release film of the release film integrated sealing material described in any one of (1) to (3) is composed of a "surface untreated polyethylene terephthalate resin film" which is inexpensive, easily available, and has excellent heat resistance. Thereby, the quality stability and economy of the release film integrated sealing material described in any one of (1) to (3) can be maintained at an extremely favorable level.

[0018] (5) The base resin of the sealing film is a polyethylene-based resin having a density of 0.870 g / cm 3 or more and 0.930 g / cm 3 or less, and is the release film integrated sealing material according to any one of (1) to (4).

[0019] In the invention of (5), the sealing film of the release film integrated sealing material described in any one of (1) to (4) is composed of a polyethylene-based resin within a specific density range. Thereby, the sealing performance of the light emitting module, which is the original performance of the release film integrated sealing material described in any one of (1) to (4) as a sealing material, that is, the resin wrapping performance (molding property) into the fine irregularities on the surface of the wiring board, the adhesion to the wiring board, and the protection performance from the impact of the light emitting element can be improved to a particularly favorable level.

[0020] (6) A laminate formed by laminating the release film integrated sealing material according to any one of (1) to (5) and a light emitting module in which a plurality of light emitting elements are mounted on a wiring board, is integrated by heat laminating while being placed on a heating plate made of metal and / or glass, and includes a heat lamination step of directly placing the release film of the release film integrated sealing material constituting the laminate on the heating plate without passing through another release film. This is a method for manufacturing an LED module.

[0021] According to the invention of (6), it is possible to avoid the quality deterioration and productivity degradation associated with the use of the release film during the heat lamination step in the manufacturing process of the self-luminous display body, and manufacture a self-luminous display body with excellent quality stability under excellent productivity.

Advantages of the Invention

[0022] According to the present invention, in the thermal lamination process performed during the manufacturing process of the self-luminous display, it is possible to avoid the loss of smoothness of the surface of the sealing material that occurs when using a release film.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0024] <Self-luminous display> First, the "self-emitting display" in this specification is a display device represented by the micro-LED TV exemplified above, and is a display device for visual information such as characters, images, and videos. This display device mounts a large number of minute light-emitting elements in a matrix on a wiring substrate, and selectively emits light from each light-emitting element by light-emitting control means connected thereto, so that the above visual information can be directly displayed on the display screen by the blinking of each light-emitting element. The release film integrated sealing material of the present invention can be particularly preferably used for an LED display device using an LED element as a light-emitting element among "self-emitting displays".

[0025] [Micro-LED Display Device] FIG. 1 is a front view of a micro-LED display device 100 which is an embodiment of a self-emitting display manufactured using the release film integrated sealing material of the present invention, and a partial enlarged view (100A) thereof. Further, FIG. 2 is a cross-sectional view showing a cross-section of the A-A portion of FIG. 1, and is a drawing for explaining the layer structure of the micro-LED display device 100 shown in FIG. 1. This micro-LED display device 100 is a self-emitting display device in which a large number of minute-sized LED elements 10 are mounted on a wiring substrate 20 as light-emitting elements. Each LED element 10 has its light emission individually controlled by light-emitting control means (not shown) such as an IC chip substrate joined separately.

[0026] In addition, the "minute-sized LED element" in this specification specifically refers to an LED element in which both the width (W) and the depth (D) of the entire light-emitting element including the LED light-emitting chip and the resin cover covering it are 300 μm or less, and the height (H) is 200 μm or less (see FIG. 3).

[0027] Furthermore, regarding the size of this "LED element with a minute size", it is more preferable that both the width and the depth are 50 μm or less, and the height is 10 μm or less. Note that this size range is the standard size range of LED elements to be mounted on micro-LED TVs, which have been developed in recent years and are expected to become the mainstream of next-generation TVs. Hereinafter, in this specification, a self-emitting display in which LED elements with a minute size having both a width and a depth of 50 μm or less and a height of 10 μm or less are arranged in a matrix at a pitch of about several μm to several tens of μm and in a number of about several thousand × several thousand or more is referred to as a "micro-LED display device".

[0028] And hereinafter, while taking the embodiment in the case where the "self-emitting display" is a "micro-LED display device" as a particularly preferable specific example among various embodiments of the present invention, a detailed description of the present invention will be given. However, the technical scope of the present invention is not limited to the application only to the "micro-LED display device". It is a technology applicable to all "self-emitting displays" according to the above definition.

[0029] In addition, in this specification, a module in which a light-emitting element is mounted on a wiring board is collectively referred to as a "light-emitting module". In the micro-LED display device 100, a main body (111) of a release film integrated sealing material 1 made of a sealing film 111 is further laminated on a light-emitting module in which a large number of LED elements 10 are mounted on a wiring board 20 to constitute an LED module 30. Note that when the release film integrated sealing material 1 is incorporated into the micro-LED display device 100 and integrated, the release film 121 has been removed, and it functions as a sealing film as a main body made of the sealing film 111. The sealing film 111 in such a state is also referred to as a sealing material main body 111 of the release film integrated sealing material as needed for explanation. Details of the release film integrated sealing material will be described later.

[0030] And in the micro-LED display device 100, a display surface panel 2 such as various optical films and transparent protective glass is further laminated on the outer surface (the display surface side in the micro-LED display device 100) of the encapsulant main body 111 of the release film integrated encapsulant that constitutes the LED module 30.

[0031] Further, by joining a plurality of light-emitting modules for self-emitting display elements in a matrix on the same plane and laminating the encapsulant main body 111 on the joined light-emitting modules in the same manner as above, an LED module for a large-sized self-emitting display element, and further, a large-sized micro-LED display device can also be configured.

[0032] (LED Module) The wiring board 20 that constitutes the LED module 30 is a circuit board formed with a wiring portion 22 formed of a metal such as copper or other conductive members in a form that can be electrically connected to the LED element 10 on the surface of the support substrate 21 as shown in FIG. 2. It is preferable to use a rigid substrate such as a glass epoxy substrate or a glass substrate, which is conventionally known as a substrate for an electronic circuit, as the support substrate 21.

[0033] In the LED module 30, as shown in FIG. 2, the LED element 10 is mounted on the wiring portion 22 in a conductive manner via the solder layer 23.

[0034] There is no particular limitation on the size of the LED module 30, but generally, those with a diagonal length of about 50 inches to 200 inches are considered preferable from the perspective of cost performance. Further, as described above, a plurality of LED modules 30 for self-emitting display elements can be joined in a matrix on the same plane to form the light-emitting surface of a self-emitting display element such as a large-sized micro-LED display device 100. For example, 100×100 LED modules 30 with a diagonal length of 6 inches can be joined vertically and horizontally to configure a micro-LED TV with a large screen having a diagonal length of 600 inches.

[0035] (LED Element) The LED element 10 that constitutes the LED module 30 is a light-emitting element that utilizes light emission at a PN junction where a P-type semiconductor and an N-type semiconductor are joined. Structures in which a P-type electrode and an N-type electrode are provided on the upper and lower surfaces of the element, and a structure in which both a P-type and an N-type electrode are provided on one side of the element have been proposed. Any of the LED elements 10 with these structures can be used in the micro-LED display device 100 of the present invention, but particularly preferably, a micro-sized LED element such as the LED element disclosed as a "chip-shaped electronic component" in Japanese Patent Application Laid-Open No. 2006-339551 can be used. The LED element disclosed in this document is said to have dimensions of approximately 25 μm × 15 μm × 2.5 μm in terms of width × depth × height.

[0036] The LED element 10 preferably includes an LED light-emitting chip 11 and a resin cover 12 that covers it. Further, as this resin cover 12, an organic insulating material such as an epoxy resin, a silicone resin, or a polyimide resin is used, and among these, an epoxy resin is particularly preferably used. The resin cover 12 formed of an epoxy resin not only simply protects the LED light-emitting chip 11 from physical impact but also plays a role of suppressing total internal reflection of light into the semiconductor due to the difference in refractive index between the semiconductor constituting the LED light-emitting chip 11 and air, thereby increasing the light emission efficiency of the LED element 10. The release film-integrated sealing material 1 is also preferable as a sealing material to be mounted on the micro-LED display device 100 in that it is formed of an olefin-based resin that is excellent in adhesion to an epoxy resin.

[0037] In the self-luminous display body of the present invention, an LED element including an LED light-emitting chip and a resin cover that covers it, and having a size where both the width and the depth are 300 μm or less and the height is 200 μm or less can be preferably used. In this case, the arrangement interval of these LED elements is preferably 0.03 mm or more and 100 mm or less.

[0038] Furthermore, in the self-luminous display of the present invention, an LED element including an LED light-emitting chip and a resin cover covering the LED light-emitting chip, and an extremely small LED element having a width and depth of 50 μm or less and a height of 10 μm or less, can be more preferably used. In this case, the arrangement interval of the LED elements is preferably 0.03 mm or more and 100 mm or less. Specifically, such a mounting mode of the LED elements is also a standard mounting mode of the LED elements in a micro LED television.

[0039] [Sealant with integrated release film] As shown in Fig. 4, the release film integrated encapsulant 1 for a self-luminous display is a multi-layer film formed by laminating an encapsulant film 111 and a release film 121. The encapsulant film 111, as the encapsulant body 111 of the release film integrated encapsulant 1, is laminated to cover the wiring board 20 and the LED elements 10 while exhibiting good molding properties in the LED module 30 in which a large number of micro-sized LED elements are mounted, thereby exerting a sealing function of protecting these LED elements 10 from external impacts, etc. On the other hand, the release film 121 exerts a function of smoothly detaching the encapsulant film 111 from the heating plate of the laminator, etc., at the end of the thermal lamination process.

[0040] In the release film integrated sealing material 1 for a self-luminous display, the sealing film 111 and the release film 121 may be joined with a predetermined adhesive strength by heat pressing or the like. The adhesive strength at the interface between the films is adjusted to a specific range that can maintain the adhesiveness between the films when integrated and provide good releasability. Specifically, the adhesive strength at the interface between the sealing film 111 and the release film 121 measured by the following adhesiveness test may be 0.3 N / 15 mm or more and 3.0 N / 15 mm or less. (Adhesion test) "In a release film integrated sealing material cut to a width of 15 mm, a release film adhered to the sealing film is subjected to a vertical peeling (50 mm / min) test using a peeling tester (Tensilon universal testing machine RTF-1150-H), and the adhesion strength of each surface is measured."

[0041] When the above-mentioned adhesion strength at the interface between the sealing film 111 and the release film 121 is less than 0.3 N / 15 mm, there is no problem with the point that the sealing film 111 can be "smoothly detached" from the release film 121 at the end of the thermal lamination process. However, in this case, delamination between layers is likely to occur at the stage before being installed in a laminator or the like as a multilayer film, which is not preferable in terms of reducing the handleability.

[0042] On the other hand, when the above-mentioned adhesion strength exceeds 3.0 N / 15 mm, the ease of peeling at the end of the thermal lamination process decreases, and it is not preferable in terms of the difficulty of "smoothly detaching" the sealing film 111 from the release film 121.

[0043] Here, more specifically, the "ability to smoothly detach the sealing film 111 from the release film 121" means that the release film integrated sealing material 1 has an interlayer adhesion such that it does not delaminate by a bending test of winding around a 30 mmφ cylindrical rod, while still being in a state where it can be easily peeled off by hand.

[0044] (Sealing film (sealing material body)) The sealing film (sealing material body) 111 constituting the release film integrated sealing material 1 is formed of a resin composition having an olefin-based resin as a base resin. As the base resin of the sealing film (sealing material body) 111, an ethylene-vinyl acetate copolymer resin (EVA) or a low-density polyethylene resin can be used. Among them, a density of 0.870 g / cm 3 or more and 0.930 g / cm 3The following polyethylene resins can be particularly preferably used. In this specification, the "base resin" refers to the resin having the largest content ratio among the resin components of the resin composition containing the base resin.

[0045] Further, when the sealing film (sealing material main body) 111 is formed of a polyethylene resin, more specifically, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or metallocene-based linear low-density polyethylene (M-LLDPE) can be preferably used. Among them, M-LLDPE synthesized using a metallocene catalyst which is a single-site catalyst can be particularly preferably used. Since M-LLDPE has few side-chain branches and a uniform comonomer distribution, it has a narrow molecular weight distribution and can be easily made into an ultra-low density. Therefore, in a self-luminous display such as the LED module 30 and the micro-LED display device 100, the adhesion of the sealing film (sealing material main body) 111 to the wiring substrate 20 made of a glass epoxy resin plate, a glass plate, or the like can be made particularly excellent.

[0046] Further, the sealing film (sealing material main body) 111 can contain a silane component as necessary. Thereby, the adhesion to the above-mentioned wiring substrate 20 can be improved to a more preferable level.

[0047] The sealing film (sealing material main body) 111 may have a single-layer structure, or may have a multilayer structure in which the same layer is formed by laminating layers made of resin compositions of a plurality of different compositions. For example, the sealing film (sealing material main body) 111 is composed of a core layer made of a polyethylene-based resin having a relatively high density and excellent heat resistance, and a skin layer made of a polyethylene-based resin having a relatively low density and excellent adhesion and exposed on the sheet surface. For example, by making the above-mentioned silane component unevenly distributed only in the skin layer to form an adhesion layer, a sealing film (sealing material main body) 111 having an excellent balance between heat resistance and adhesion can be obtained.

[0048] As the material of the "silane component" to be contained in the sealing film (sealing material body) 111, a silane-modified polyethylene resin can be used. This silane-modified polyethylene resin is obtained by graft-polymerizing an ethylenically unsaturated silane compound as a side chain onto a linear low-density polyethylene (LLDPE) or the like serving as the main chain. In such a graft copolymer, the degree of freedom of the silanol group contributing to the adhesive force becomes high. Thereby, the adhesion and adhesion durability of the sealing film (sealing material body) 111 to the wiring board 20 such as a glass epoxy substrate can be improved. The silane-modified polyethylene resin can be produced, for example, by the method described in JP-A-2003-46105.

[0049] The thickness of the sealing film (sealing material body) 111 is preferably 50 μm or more and 500 μm or less. However, when the LED element 10 to be coated is an extremely small-sized LED element having a height of 10 μm or less, the thickness of the sealing film (sealing material body) 111 is preferably 25 μm or more and 100 μm or less. Depending on the size of the LED element to be coated, when the thickness of the sealing film (sealing material body) 111 is 50 μm or more, or 25 μm or more, respectively, the LED element can be sufficiently protected from external impacts. On the other hand, when the thickness of the sealing film (sealing material body) 111 is 1000 μm or less, it is easy to exhibit moldability in the thermal lamination process. Specifically, during thermal lamination processing in a state where the LED element 10 is coated, the resin constituting the sealing film (sealing material body) 111 can sufficiently wrap around the unevenness on the surface of the wiring board 20 on which the LED element 10 is mounted, and it is easy to perform a good lamination without gaps. Further, when the LED element to be coated is an extremely small-sized LED element having a height of 10 μm or less, when the thickness of the sealing film (sealing material body) 111 is 100 μm or less, it is easy to maintain the light transmittance of the sealing material body 111 made of the sealing film 111 at a preferable level in the self-luminous display body after integration.

[0050] (Release film) The melting point of the release film 121 that constitutes the release film integrated sealing material 1 may be 220°C or higher and 270°C or lower. For this reason, the release film 121 can be formed of a resin composition having a resin with a melting point of 220°C or higher and 270°C or lower as a base resin. From such a perspective, as the base resin of the release film 121, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc. can be preferably used.

[0051] And the release film 121 is characterized in that the wetting index according to JIS K 6768 of the surface of the release surface 122, which is the surface on the interface side with the sealing film 111, is 25 Dyne or more and 40 Dyne or less. If the wetting index of the release surface 122 is 25 Dyne or more, after being completed in an integrated state as a multilayer film and before being distributed as a product and subjected to heat lamination processing, the necessary adhesion between the films required for the release film integrated sealing material 1 can be ensured. On the other hand, if the wetting index of the release surface 122 is 40 Dyne or less, the releasability to the extent that the sealing film 111 can be smoothly detached from the release film 121 after the heat lamination processing can be maintained.

[0052] In order to adjust the wetting index of the release surface 122 of the release film integrated sealing material 1 within the above range, as the resin film constituting the release film 121, at least on the surface that becomes the release surface 122 at the time of integration with the sealing film 111, it is preferable to use a "surface untreated polyethylene terephthalate resin film" on which no surface treatment for adjusting adhesion and releasability has been performed. The "surface treatment for adjusting adhesion and releasability" includes, for example, all known surface treatment methods for the same purpose, such as corona treatment for improving adhesion or various surface coating treatments for enhancing peelability.

[0053] Furthermore, the wetting index of the corona-treated surface of polyethylene terephthalate (corona-treated PET), which is common on the surface, exceeds the above upper limit value of 40 Dyne and is about 50 Dyne. Also, as described above, conventionally, the wetting index of the surface of a fluorine-based film that has been widely used as a release film is usually about 20 Dyne, which is less than the above lower limit value.

[0054] As described above, conventionally, during thermal lamination processing, the releasability of the sealing film from the heating plate of the laminator, etc. was ensured by separately placing a single release film, which was made easier, on the above heating plate, etc. in advance. As the release film preferably used in this case, for example, a release film coated with a release agent such as silicone to improve the releasability, that is, a release film subjected to a "surface treatment for adjusting the releasability" was widely used. However, if these release films with enhanced releasability are used as the release film 121 of the release film integrated sealing material 1 and integrated with the resin film forming the sealing film 111 made of an olefin resin during film formation, the adhesion between layers will be insufficient, and delamination between layers is likely to frequently occur from the end of the laminate constituting the multilayer film. On the other hand, when the above "untreated polyethylene terephthalate resin film" is used as the resin film constituting the release film 121, such delamination can be sufficiently prevented, and moreover, the necessary releasability can be maintained.

[0055] Further, the release surface 122 of the release film 121 preferably has a surface roughness Rz (JIS B 0601-2001) of 80 nm or more. When the surface roughness Rz is less than 80 nm, when integrating the resin film constituting the sealing film 111 and the resin film constituting the release film 121 in roll-to-roll production equipment, wrinkles and meandering of the film are likely to occur. Due to the above-described minute shaping process, these manufacturing defects can be sufficiently prevented. In a conventional single release film, the shaping process performed to enhance releasability is generally a process in which the surface roughness Rz (JIS B 0601-2001) of the release surface exceeds 500 nm. However, in the release surface 122 of the release film integrated sealing material 1, the surface roughness Rz is preferably limited to 500 nm or less at most in order to maintain the required interlayer strength of the multilayer film.

[0056] [Method for manufacturing a release film integrated sealing material for a self-luminous display] The release film integrated sealing material of the present invention can be manufactured by passing through a film forming step of melt-forming a sealing material composition for forming each layer into a sheet shape and a laminating step of laminating and integrating the formed sheets by heat pressing. This melt molding can be performed by various molding methods commonly used for ordinary thermoplastic resins, that is, injection molding, extrusion molding, blow molding, compression molding, rotational molding, and the like. These steps can be continuously performed online in roll-to-roll production equipment as shown in FIG. 7, for example.

[0057] FIG. 7 is a drawing for explaining the manufacturing method of the release film integrated sealing material 1, and schematically shows an example of an embodiment when the above-described process is performed by roll-to-roll production equipment 50. In this roll-to-roll production equipment 50, the molten resin for forming the sealing film 111 is extruded from the T-die 51 and nipped between the rubber roll 541 and the embossing roll 542, whereby the film-shaped resin base material 111a constituting the sealing film 111 is formed. At that time, the film-shaped resin base material 121a constituting the release film 121 is also fed out between the above-described rubber roll 541 and embossing roll 542 from the first paper feed roll 52, and the two base materials are integrated by being pressure-bonded. Further, at this time, if necessary, other functional film 131a is also supplied from the second paper feed roll 53 and integrated in the same manner. Each integrated base material passes through the cooling roll 543 and is wound around the discharge roll 54 in the state of an integrated laminate.

[0058] In the release film integrated sealing material 1 of the present invention, by maintaining the surface roughness of the surface (peeling surface) of the release film 121 (the film-shaped resin base material 121a constituting the release film 121) at Rz 80 nm or more, the minimum slipperiness between the resin base material 111a constituting the sealing film 111 and the resin base material 121a constituting the release film 121 is maintained, and in roll-to-roll production equipment, the generation of fine wrinkles and meandering when running between the rolls of guide rolls such as the rubber roll 541 and the embossing roll 542, which are likely to occur in the process of laminating and integrating, can be reduced. When the surface roughness is less than 80 nm, if the slipperiness between the above-described guide roll and the film decreases and meandering or the like occurs, wrinkles are likely to form, and the process of laminating and integrating may become difficult.

[0059] <Method for manufacturing a self-luminous display> [Method for manufacturing an LED module] The LED module 30 for the self-luminous display body that constitutes the micro-LED display device 100 is obtained by laminating a wiring board 20 on which LED elements 10 are mounted and a release film integrated sealing material 1 in such a manner that the surface on the side of the sealing film 111 covers the wiring board 20, and subjecting this laminate to a thermal lamination process in which the laminate is heated and pressure-bonded in a state where it is placed on the heating plate of a laminator to be integrated.

[0060] As shown in FIGS. 5 and 6, this thermal lamination process is performed by placing the above laminate on the heating plate 41 of the laminator 40 directly or via an auxiliary heating plate 42 on the side of the release film 121 of the release film integrated sealing material 1, and in this state, pressing the laminate holding plate 43 against the laminate by evacuation. Note that the auxiliary heating plate 42 is an auxiliary member arranged to compensate for the lack of smoothness of the surface of the heating plate 41 made of an iron plate or the like, and a glass plate such as blue plate glass having normal thermal conductivity and surface smoothness is usually used. In this specification, the "heating plate" includes not only those composed only of the heating plate 41, but also, when the auxiliary heating plate 42 is laminated on the heating plate 41, the laminate composed of both of these is regarded as the "heating plate".

[0061] Specifically, the above laminate is placed on the heating plate 41(42) by directly placing the exposed surface 123 of the release film 121 of the release film integrated sealing material 1 on the heating plate 41(42). Note that usually, in this case, a release film integrated sealing material 1 wider than the wiring board 20 on which the LED elements 10 are mounted is prepared, and the release film 121 is half-cut so that the sealing film 111 has an appropriate size that matches the module size when integrated, and a process of cutting off unnecessary ends of the sealing film 111 is performed.

[0062] The sealing film 111 of the release film integrated sealing material 1 that has undergone the thermal lamination process in this way has an olefin-based resin forming the same layer exhibit sufficient moldability and adhere to the wiring board 20 on which the LED elements 10 are mounted with good adhesion strength.

[0063] [Method for manufacturing self-luminous display body] On the LED module 30 that can be obtained by the above manufacturing method, the display surface panel 2 is further laminated and integrated by means such as adhesive bonding, etc., whereby the micro LED display device 100 shown in FIG. 2, or various self-luminous display bodies having a similar layer structure can be manufactured.

Example

[0064] Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples.

[0065] In a roll-to-roll type production facility as shown in FIG. 7, a test production of the release film integrated sealing material according to the present invention was carried out by the above manufacturing method.

[0066] [Manufacture of the release film integrated sealing material of the example] (Sealing film) The following resin composition for sealing film was extruded at an extrusion temperature of 210 °C, a take-up speed of 1.1 m / min, and a film thickness of 150 μm using a film forming machine having a φ30 mm extruder and a 200 mm wide T-die.

[0067] (Resin composition for sealing film) Based on 100 parts by mass of the following base resin, 5 parts by mass of additive resin 1 (weather-resistant masterbatch) and 20 parts by mass of additive resin 2 (silane-modified polyethylene resin) were mixed at a ratio to form a sealing material composition for forming the sealing film of the release film integrated sealing material of the example. Base resin 1 : Metallocene linear low-density polyethylene resin (M-LLDPE) with a density of 0.901 g / cm 3 , a melting point of 93 °C, and an MFR of 2.0 g / 10 min at 190 °C. Additive resin 1 (weather-resistant masterbatch) : Density 0.919 g / cm 3, with respect to 100 parts by mass of a low-density polyethylene resin having an MFR of 3.5 g / 10 min at 190 °C: 0.6 parts by mass of KEMISTAB 62 (HALS); 3.5 parts by mass of KEMISORB 12 (UV absorber); 0.6 parts by mass of KEMISORB 79 (UV absorber). Additive resin 2 (silane-modified polyethylene resin) : density 0.898 g / cm 3 , with respect to 95 parts by mass of a metallocene linear low-density polyethylene resin having a density of 0.898 g / cm and an MFR of 3.5 g / 10 min, 5 parts by mass of vinyltrimethoxysilane and 0.15 parts by mass of dicumyl peroxide as a radical generator (reaction catalyst) were mixed and melt-kneaded at 200 °C to obtain a silane-modified polyethylene resin. The density of this additive resin 2 is 0.901 g / cm 3 , and the MFR is 1.0 g / 10 min.

[0068] (Release film) The following resin film for release film was integrated with the sealing film melt-extruded as described above by pressing the resin film constituting the release film. (Resin film for release film) A polyethylene terephthalate (PET) film having a melting point of 260 °C, thickness 50 μm. The wetting index measured in accordance with JIS K 6768 on the surface of this resin film was 30 Dyne.

[0069] <Manufacture of release film-integrated sealing material of comparative example> A release film-integrated sealing material of a comparative example was manufactured under the same conditions as in the example, except that the following general-purpose release film, which had been processed to enhance releasability, was used as the resin film constituting the release film.

[0070] (General-purpose release film) A polyethylene terephthalate (PET) film having a melting point of 260 °C, thickness 50 μm. However, it is a "resin film with surface release treatment" having a silicone release treatment applied to the surface. The wetting index measured in accordance with JIS K 6768 on the surface of this resin film was 18 Dyne.

[0071] <Evaluation Example 1: Adhesion Strength between Films> For the release film integrated sealants of each of the examples and comparative examples, the adhesion strength (N / 15 mm) at the interface between the sealing film and the release film was measured by the following "adhesion test" (under the same conditions as the above-described adhesion test). The results are shown in Table 1. (Adhesion Test) In the release film integrated sealant cut to a width of 15 mm, a vertical peeling (50 mm / min) test was performed on the release film adhered to the sealing film using a peeling tester (Tensilon universal testing machine RTF-1150-H) to measure the adhesion strength (N / 15 mm) at the interface between the two films.

[0072] <Evaluation Example 2: Ease of Handling before Thermal Lamination> Regarding the ease of handling before thermal lamination for the release film integrated sealants of each of the examples and comparative examples, an operation of manually placing each sealant in a laminator was performed, and the ease of handling before thermal lamination was evaluated sensorially based on whether unnecessary delamination occurred during the process of this operation. The operation was separately performed by 5 operators, and the evaluation criteria were as follows. The evaluation results are shown in Table 1 as "Ease of Handling". (Evaluation Criteria) A: During the above manual operation, delamination between the sealing film and the release film did not occur during the operation by any of the operators. B: During the above manual operation, delamination between the sealing film and the release film occurred during the operation by 1 or fewer operators. C: During the above manual operation, delamination between the sealing film and the release film occurred during the operation by 2 or more operators.

[0073]

Table 1

[0074] <Evaluation Example 3: Ease of Peeling after Thermal Lamination> Using an existing laminator, the production of an LED module using the release film integrated sealing material of the example and the production of an LED module using the above sealing film as a sealing material and using the above "general-purpose release film" as a separate release material without integrating it with the sealing film were each experimentally carried out according to the above [Method for manufacturing an LED module]. As a result, it was confirmed that there was no problem with the peelability of the sealing material after the thermal lamination process, and the sealing film (sealing material) could be "smoothly detached" from the release film (release material).

[0075] From the results of the test production of the above LED module and the test and evaluation results in Table 1, it can be seen that the release film integrated sealing material of the present invention can avoid the loss of smoothness of the surface of the sealing material that occurs when using a release film in the thermal lamination process performed in the manufacturing process of the self-luminous display body and the resulting deterioration in the quality of the self-luminous display body.

Explanation of symbols

[0076] 1 Release film integrated sealing material 111 Sealing film (sealing material body) 121 Release film 122 Release surface 123 Exposed surface 10 LED element 11 LED light-emitting chip 12 Resin cover 20 Wiring board 21 Support board 22 Wiring part 23 Solder layer 30 LED module for self-luminous display body 40 Laminator 41 Heating plate 42 Heating plate (auxiliary heating plate) 43 Laminate pressing plate 50 Roll-to-roll production equipment 51 T-die 52 First feeding roll 53 Second feeding roll 54-sheet paper roll 541 Rubber roll 542 Embossing roll 543 Cooling roll 2 Display surface panel 100, 100A, 100B Micro LED display device (self-emitting display body)

Claims

1. A sealing material for a self-luminous display, which is a multilayer film formed by laminating a sealing film and a release film, wherein the release film is based on any one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT), and the surface roughness Rz of the release surface, which is the surface on the interface side with the sealing film, is 80 nm or more and 500 nm or less, and a release film integrated sealing material in which the adhesion strength at the interface between the sealing film and the release film measured by the following adhesion test is 0.3 N / 15 mm or more and 3.0 N / 15 mm or less. Adhesion test: In a release film integrated sealing material cut to a width of 15 mm, the release film adhered to the sealing film is subjected to a vertical peeling (50 mm / min) test using a peeling tester (Tensilon universal testing machine RTF-1150-H), and the adhesion strength at the interface between the two films is measured.

2. A sealing material for a self-luminous display, which is a multilayer film formed by laminating a sealing film and a release film, wherein the sealing film contains a silane-modified polyethylene resin, and the release film is an untreated polyethylene terephthalate resin film in which no treatment using a release agent has been performed as a surface treatment for adjusting adhesion and release properties on the release surface, which is the surface on the interface side with the sealing film, and a release film integrated sealing material in which the adhesion strength at the interface between the sealing film and the release film measured by the following adhesion test is 0.3 N / 15 mm or more and 3.0 N / 15 mm or less. Adhesion test: In a release film integrated sealing material cut to a width of 15 mm, the release film adhered to the sealing film is subjected to a vertical peeling (50 mm / min) test using a peeling tester (Tensilon universal testing machine RTF-1150-H), and the adhesion strength at the interface between the two films is measured.

3. A laminate comprising the release film integrated sealing material according to Claim 1 or 2, and a light-emitting module in which a plurality of light-emitting elements are mounted on a wiring board, is integrated by heat lamination, which includes a heat lamination step of heating and pressing the laminate while it is placed on a heating plate made of metal and / or glass. ​ A method for manufacturing an LED module, wherein the heat pressure bonding is performed by directly placing the release film of the release film integrated sealing material constituting the laminate on the heating plate without interposing another release film.

Images