JP7139833B6 - Encapsulant with integrated release film for self-luminous displays - Google Patents

Description

The present invention relates to a sealing material for a self-luminous display. Specifically, this encapsulant is a release film-integrated encapsulant in which a release film is pre-integrated during film production, and it improves the quality stability and productivity of LED modules for self-luminous displays. It is a sealing material that can be improved.

BACKGROUND ART As a next-generation display device to replace various liquid crystal display devices, development of self-luminous display devices typified by micro LED televisions is progressing (see Patent Document 1). Usually, these self-luminous displays are made by laminating a sealing film to protect the light-emitting elements on the light-emitting surface side of a light-emitting module in which light-emitting elements such as LED elements are mounted on a wiring board. This is a configuration in which a display surface panel such as various optical films and transparent protective glass is further laminated on an LED module for a self-luminous display (see Patent Documents 2 and 3).

A sealing material for a self-luminous display that constitutes an LED module is required to have excellent adhesion to, for example, a glass epoxy resin or a glass plate that constitutes a wiring board of an LED module or the like. As examples of sealing films having such adhesive properties, Patent Document 2 discloses a sealing material containing polyethylene, and Patent Document 3 discloses a sealing material containing acid-modified polyethylene, which has better adhesion to glass. Disclosed.

Incidentally, an LED module is manufactured by a thermal lamination process in which a laminate in which a light emitting module and a sealing film are laminated is placed on a heating plate and bonded under heat and pressure to be integrated. In this process, in order to ensure necessary and sufficient releasability between the sealing film with excellent adhesion and the heating plate after the completion of the above process, it is necessary to It has been necessary to interpose various release films made of polyester resin or the like between the film and the heating plate.

Conventionally, such release films have been made of high-performance fluororesins such as PTFE (polytetrafluoroethylene) and ETFE (ethylene tetrafluoroethylene), or polyester resins such as PET (polyethylene terephthalate). Various types of release films are used (see Patent Document 4).

However, when performing the above thermal lamination process with these release films interposed, the release film itself may be deformed due to heating, or fine foreign matter may enter the gap between the release film and the sealing film. Due to contamination, etc., the smoothness of the surface of the encapsulant after film formation may be impaired. Loss of smoothness on the surface of the encapsulant causes deterioration in the optical properties and long-term durability of the self-luminous display. At the production site of LED modules, a new technical means to avoid the quality deterioration caused by the use of such a release film has been required.

Japanese Patent Application Publication No. 2018-14481 JP2017-9725A Japanese Patent Application Publication No. 2014-148584 JP2017-35382A

The present invention was made in view of the above-mentioned circumstances, and addresses the problem of the surface of the encapsulant that occurs when a release film is used in the thermal lamination process performed in the manufacturing process of self-luminous displays. It is an object of the present invention to provide a new technical means that can avoid loss of smoothness and the resulting deterioration in quality of self-luminous displays.

As a result of extensive research, the inventors of the present invention have developed an encapsulating material for self-luminous displays that is integrated with a release film, in which a release film is integrated in advance during film production. The inventors have discovered that the above problems can be solved, and have completed the present invention. Specifically, the present invention provides the following.

(1) A sealing material for a self-luminous display, which is a multilayer film formed by laminating a sealing film and a release film, and the sealing film uses an olefin resin as a base resin. , the release film has a melting point of 220° C. or more and 270° C. or less, and has an adhesion strength of 0.3 N/15 mm or more at the interface between the sealing film and the release film as measured by the following adhesion test. A release film-integrated sealing material having a pressure of 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 that is in close contact with the sealing film is vertically peeled using a peel tester (Tensilon Universal Tester RTF-1150-H). (50 mm/min) to measure the adhesion strength at the interface between both films.

In the invention (1), the sealing material for the self-luminous display is a multilayer film in which the sealing film and the release film are integrated in advance. The lower limit of the adhesion strength between the two films is at least the strength that can maintain the handleability as an integrated multilayer film at a preferable level, and the upper limit is set at a level that allows for good mold release. The strength is set below that which can maintain the properties. According to such an encapsulating material integrated with a release film, the smoothness of the surface of the encapsulating material, which occurs due to the use of a release film, can be improved during the thermal lamination process performed in the manufacturing process of self-luminous displays. losses can be avoided.

(2) The release film according to (1), wherein the release surface, which is the surface on the interface side with the sealing film, has a wettability index according to JIS K 6768 of 25 Dyne or more and 40 Dyne or less. Molded film integrated sealing material.

In the invention (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 release film is placed on the interface side of both layers. The wetting index of the release surface of the mold film was adjusted to a specific range different from that of conventional single release films. Thereby, the quality stability of the release film-integrated sealing material that satisfies the above-mentioned requirements regarding the adhesion strength between films in the invention (1) can be easily maintained at a good level.

_{(3) The release film has a surface roughness: Rz of the release surface, which is the surface on the interface side with the sealing film.} 80nm or more and 500nm or less _{The release film integrated sealing material according to (1) or (2).}

_{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 interface side of both layers is Surface roughness of the release surface of the release film to be placed: Rz} 80nm or more and 500nm or less _{adjusted to the range. This eliminates wrinkles in the film running between rolls, which tend to occur during the process of laminating and integrating the resin film that makes up the sealing film and the resin film that makes up the release film in roll-to-roll production equipment. It is possible to reduce the occurrence of meandering and meandering.}

(4) The release film is a polyethylene terephthalate resin film, and the polyethylene terephthalate resin film has a release surface, which is a surface on the interface side with the sealing film, for adjusting adhesion and release properties. The release film-integrated sealing material according to any one of (1) to (3), which is a surface-untreated polyethylene terephthalate resin film that has not been subjected to surface treatment.

In the invention (4), the release film of the release film-integrated sealing material according to any one of (1) to (3) is used as a "surface-untreated" release film that is inexpensive, easily available, and has excellent heat resistance. Constructed from polyethylene terephthalate resin film. Thereby, the quality stability and economic efficiency of the release film-integrated sealing material according to any one of (1) to (3) can be maintained at extremely favorable levels.

(5) The release film according to any one of (1) to (4), wherein the base resin of the sealing film is a polyethylene resin having a density of 0.870 g/cm ³ or more and 0.930 g/cm ³ or less. Integrated encapsulant.

In the invention (5), the sealing film of the release film-integrated sealing material according to any one of (1) to (4) is composed of a polyethylene resin having a specific density range. This improves the sealing performance of the light-emitting module, which is the original performance of the release film-integrated sealant described in any one of (1) to (4) as a sealant, that is, the fineness of the surface of the wiring board. The ability of the resin to wrap around irregularities (molding ability), the adhesion to the wiring board, and the ability to protect the light emitting element from impact can be improved to particularly desirable levels.

(6) A laminate formed by laminating the release film-integrated sealing material described in (1) to (5) and a light emitting module in which a plurality of light emitting elements are mounted on a wiring board,
The method includes a thermal lamination process in which the heating plate is placed on a heating plate made of metal and/or glass and integrated by heating and pressing, and the heating and pressing is performed with the release film integrally forming the laminate. A method for manufacturing an LED module, comprising directly placing the release film of the material on the heating plate without using another release film.

(6) According to the invention in (6), quality stability is excellent by avoiding quality deterioration and productivity deterioration associated with the use of a release film during the thermal lamination process in the manufacturing process of self-luminous displays. A self-luminous display can be manufactured with excellent productivity.

According to the present invention, it is possible to avoid loss of smoothness of the surface of the encapsulant that occurs when a release film is used in the thermal lamination step performed in the manufacturing process of a self-luminous display.

A plan view of an image display surface of a self-luminous display body using an LED module for a self-luminous display body in which a sealing film constituting the release film-integrated sealing material of the present invention is laminated on a light-emitting module. and a partially enlarged plan view thereof. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1; FIG. 2 is a perspective view of an LED element constituting the LED module for the self-luminous display shown in FIG. 1. FIG. FIG. 2 is a cross-sectional view schematically showing an example of the layer structure of the release film-integrated sealing material of the present invention. FIG. 2 is a drawing for explaining a method of manufacturing an LED module for a self-luminous display using the release film-integrated sealing material of the present invention. FIG. 6 is a partially enlarged view of FIG. 5, and is a drawing for explaining how the sealing film is placed on the heating plate of the laminator. FIG. 2 is a drawing for explaining a method for manufacturing a release film-integrated sealing material of the present invention.

<Self-luminous display>
First, the term "self-luminous display" in this specification refers to a display device typified by the micro LED television exemplified above, and is a display device for visual information such as text, images, and moving images. This display device displays the above visual information by mounting a large number of minute light emitting elements in a matrix on a wiring board, and selectively causing each light emitting element to emit light using a light emission control means connected to the light emitting elements. This is a display device that can display images directly on a display screen by blinking light-emitting elements. Note that the release film-integrated sealing material of the present invention can be particularly preferably used for an LED display device that uses an LED element as a light emitting element, among "self-luminous displays".

[Micro LED display device]
FIG. 1 is a front view and a partially enlarged view (100A) of a micro LED display device 100, which is an embodiment of a self-luminous display manufactured using the release film-integrated sealing material of the present invention. It is. Further, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and is a drawing for explaining the layer structure of the micro LED display device 100 shown in FIG. This micro LED display device 100 is a self-luminous display device in which a large number of micro-sized LED elements 10 are mounted on a wiring board 20 as light emitting elements. The light emission of each LED element 10 is individually controlled by a light emission control means (not shown) such as an IC chip substrate that is separately bonded.

In addition, in this specification, "micro-sized LED element" specifically refers to the width (W) and depth (D) of the entire light emitting element including the LED light emitting chip and the resin cover that covers it. ) are all 300 μm or less, and the height (H) is 200 μm or less (see FIG. 3).

Further, regarding the size of this "micro-sized LED element", it is more preferable that the width and depth are both 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 mounted in micro LED televisions, which have been developed in recent years and are expected to become mainstream in next-generation televisions. Hereinafter, in this specification, micro-sized LED elements each having a width and depth of 50 μm or less and a height of 10 μm or less are arranged at a pitch of several 1000×several 1000 at a pitch of several μm to several tens of μm. A self-luminous display device arranged in a matrix in a number equal to or more than 100% is called a "micro LED display device."

In the following, the present invention will be described while taking up an embodiment in which the "self-luminous display" is a "micro LED display" as a particularly preferable specific example of various embodiments of the present invention. A detailed explanation will be given below. However, the technical scope of the present invention is not limited to application only to "micro LED display devices". This technology is also applicable to all "self-luminous display bodies" as defined above.

Furthermore, 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 light emitting module in which a large number of LED elements 10 are mounted on a wiring board 20 is further provided with a main body (111) of a release film integrated sealing material 1 made of a sealing film 111. The LED module 30 is configured by stacking them. 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 is removed, and the main body made of the sealing film 111 is a sealing film. However, the sealing film 111 in such a state is also referred to as the 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.

In the micro LED display device 100, the display surface panel 2, such as various optical films and transparent protective glass, is further attached to the sealing material main body 111 of the release film integrated sealing material constituting the LED module 30. It is laminated on the outer surface (the display surface side of the micro LED display device 100).

Furthermore, by joining a plurality of light-emitting modules for self-luminous displays in a matrix on the same plane and laminating the encapsulant body 111 on the joined light-emitting modules in the same manner as described above, large-sized It is also possible to configure an LED module for a self-luminous display, and furthermore, a large micro LED display device.

(LED module)
As shown in FIG. 2, the wiring board 20 constituting the LED module 30 is formed of metal such as copper or other conductive material on the surface of the support board 21 in a form that allows conduction with the LED elements 10. This is a circuit board on which a wiring section 22 is formed. As the support substrate 21, it is preferable to use a hard substrate such as a glass epoxy substrate or a glass substrate that is conventionally known as a substrate for electronic circuits.

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

Although there is no particular limitation on the size of the LED module 30, it is generally preferable to have a diagonal length of about 50 inches to 200 inches from the viewpoint of cost performance. Furthermore, as described above, a plurality of LED modules 30 for self-emissive displays are joined in a matrix on the same plane to constitute the light-emitting surface of a self-emissive display such as the large micro LED display device 100. can do. For example, 100 x 100 LED modules 30 each having a diagonal length of 6 inches can be joined vertically and horizontally to form a micro LED television with a large screen having a diagonal length of 600 inches.

(LED element)
The LED element 10 constituting 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. A structure 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 the P-type and N-type electrodes are provided on one side of the element have been proposed. Any structure of the LED element 10 can be used in the micro LED display device 100 of the present invention, but micro-sized LED elements such as the LED element disclosed as a "chip-shaped electronic component" in Japanese Patent Application Laid-open No. 2006-339551 can be used. It is particularly preferable to use an LED element. The LED element disclosed in the document is said to have a width x depth x height of approximately 25 μm x 15 μm x 2.5 μm.

It is preferable that the LED element 10 includes an LED light emitting chip 11 and a resin cover 12 covering it. Further, as the resin cover 12, organic insulating materials such as epoxy resin, silicone resin, and polyimide resin are used, and among these, epoxy resin is particularly preferably used. The resin cover 12 made of epoxy resin not only protects the LED light emitting chip 11 from physical impact, but also protects the inside of the semiconductor due to the difference in refractive index between the semiconductor constituting the LED light emitting chip 11 and air. This is because it also plays the role of suppressing total reflection of light and increasing the luminous efficiency of the LED element 10. The release film-integrated sealing material 1 is preferable as a sealing material to be mounted on the micro LED display device 100 because it is made of an olefin resin that also has excellent adhesion to epoxy resin.

In the self-luminous display of the present invention, the LED element includes an LED light-emitting chip and a resin cover covering it, and has a width and depth of 300 μm or less and a height of 200 μm or less. LED elements of the same size can be preferably used. In this case, the arrangement interval of the LED elements is preferably 0.03 mm or more and 100 mm or less.

Further, in the self-luminous display of the present invention, the LED element includes an LED light-emitting chip and a resin cover covering it, and the width and depth are both 50 μm or less, and the height is 50 μm or less. More preferably, an LED element having an extremely small size of 10 μm or less can be 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 manner of mounting an LED element is also a standard manner of mounting an LED element in a micro LED television.

[Release film integrated sealing material]
As shown in FIG. 4, the release film-integrated sealing material 1 for a self-luminous display is a multilayer film in which a sealing film 111 and a release film 121 are laminated. The sealing film 111 serves as the sealing material main body 111 of the release film-integrated sealing material 1 in the LED module 30 in which a large number of minute-sized LED elements are mounted, while exhibiting good molding properties and attaching to the wiring board. 20 and the LED element 10 and are laminated, it exhibits a sealing function that protects these LED elements 10 from external impacts and the like. On the other hand, the release film 121 functions to smoothly release the sealing film 111 from the heating plate of the laminator, etc. at the end of the thermal lamination process.

In the release film-integrated sealing material 1 for a self-luminous display, the sealing film 111 and the release film 121 may be bonded to each other with a predetermined adhesion strength by heat compression bonding or the like. The adhesion strength at the interface between the films is adjusted to a specific range that allows both maintenance of adhesion between the films during integration and good mold releasability. Specifically, the adhesion strength at the interface between the sealing film 111 and the release film 121 measured by the following adhesion test may be 0.3 N/15 mm or more and 3.0 N/15 mm or less.
(Adhesion test)
"In the release film-integrated sealing material cut to a width of 15 mm, the release film that is in close contact with the sealing film is vertically peeled (50 mm/ min) test and measure the adhesion strength of each surface.

If 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, the sealing film 111 is "smoothly detached" from the release film 121 at the end of the thermal lamination process. There is no problem with the "can be done" point. However, in this case, peeling between the layers tends to occur before the multilayer film is installed in a laminator or the like, which is undesirable in that handling properties deteriorate.

On the other hand, if the adhesion strength exceeds 3.0 N/15 mm, the ease of peeling at the end of the thermal lamination process will decrease, and the sealing film 111 will be "smoothly detached" from the release film 121. This is not preferable in that it becomes difficult.

Here, "the sealing film 111 can be smoothly removed from the release film 121" mentioned above means, more specifically, that the release film-integrated sealing material 1 is attached to a cylindrical rod with a diameter of 30 mm. This means that the layer has adhesion between the layers to the extent that it does not peel off depending on the winding and bending test, but it also means that it can be peeled off very easily by hand.

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

In addition, when the sealing film (sealing material main body) 111 is formed of polyethylene resin, more specifically, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or metallocene-based linear low density polyethylene is used. (M-LLDPE) can be preferably used. Among these, M-LLDPE, which is synthesized using a metallocene catalyst that is a single-site catalyst, can be particularly preferably used. M-LLDPE has less side chain branching and a uniform distribution of comonomers, so it has a narrow molecular weight distribution and can be easily made into ultra-low density. In this self-luminous display, the adhesion of the sealing film (sealing material main body) 111 to the wiring board 20 made of a glass epoxy resin plate, a glass plate, etc. can be made particularly excellent.

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

The sealing film (sealing material main body) 111 may have a single-layer structure, but it may have a multi-layer structure in which the same layer is further laminated with a plurality of layers made of resin compositions having different compositions. may have been done. For example, the sealing film (sealing material main body) 111 has a core layer made of polyethylene resin with relatively high density and excellent heat resistance, and a sheet surface made of polyethylene resin with relatively low density and excellent adhesion. For example, by unevenly distributing the above-mentioned silane component only in the skin layer to form an adhesive layer, the sealing film (sealing material main body) has an excellent balance between heat resistance and adhesion. 111.

A silane-modified polyethylene resin can be used as the material for the "silane component" contained in the sealing film (sealing material main body) 111. This silane-modified polyethylene resin is obtained by graft polymerizing an ethylenically unsaturated silane compound as a side chain to linear low density polyethylene (LLDPE) as a main chain. Such a graft copolymer has a high degree of freedom in the silanol groups that contribute to adhesive strength. Thereby, the adhesion and adhesion durability of the sealing film (sealing material main body) 111 to the wiring board 20 such as a glass epoxy board can be improved. The silane-modified polyethylene resin can be produced, for example, by the method described in JP-A No. 2003-46105.

The thickness of the sealing film (sealing material main body) 111 is preferably 50 μm or more and 500 μm or less. However, if the LED element 10 to be covered is an extremely small LED element with a height of 10 μm or less, the thickness of the sealing film (sealing material main body) 111 may be 25 μm or more and 100 μm or less. preferable. Depending on the size of the LED element to be covered, the thickness of the sealing film (sealing material main body) 111 is 50 μm or more or 25 μm or more, respectively, so that the LED element can be sufficiently protected from external impact. can do. On the other hand, when the thickness of the sealing film (sealing material main body) 111 is 1000 μm or less, moldability in the thermal lamination process is easily exhibited. Specifically, during thermal lamination processing with the LED element 10 covered, the resin constituting the sealing film (sealing material main body) 111 is removed from the unevenness of the surface of the wiring board 20 on which the LED element 10 is mounted. It is easy to wrap around the surface sufficiently and perform good lamination with no gaps. Furthermore, when the LED element to be covered is an extremely small LED element with a height of 10 μm or less, if the thickness of the sealing film (sealing material main body) 111 is 100 μm or less, it is possible to integrate the LED element. In the subsequent self-luminous display, the light transmittance of the sealing material main body 111 made of the sealing film 111 can be easily maintained at a preferable level.

(Release film)
The melting point of the release film 121 constituting the release film integrated sealing material 1 may be 220°C or more and 270°C or less. For this purpose, the release film 121 can be formed from a resin composition whose base resin is a resin having a melting point of 220° C. or higher and 270° C. or lower. From this viewpoint, as the base resin for the release film 121, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc. can be preferably used.

The release film 121 is characterized in that the surface of the release surface 122, which is the surface on the interface side with the sealing film 111, has a wettability index according to JIS K 6768 of 25 Dyne or more and 40 Dyne or less. If the wetting index of the release surface 122 is 25 Dyne or more, the release film will not be able to stand between the time it is completed as a multilayer film and the time it is distributed as a product and subjected to thermal lamination processing. The required adhesion between the films required for the body 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 release property can be maintained to the extent that the sealing film 111 can be smoothly removed from the release film 121 after the thermal lamination process. I can do it.

In order to adjust the wetting index of the peeling surface 122 of the release film integrated sealing material 1 within the above range, the resin film constituting the release film 121 must be peeled at least when integrated with the sealing film 111. It is preferable to use a "surface-untreated polyethylene terephthalate resin film" that has not been subjected to surface treatment for adjusting adhesion and mold releasability for the surface 122. "Surface treatment to adjust adhesion and mold releasability" refers to, for example, corona treatment to improve adhesion, various surface coating treatments to improve releasability, and other similar purposes. This includes all known surface treatment methods.

The wettability index of the treated surface of polyethylene terephthalate (corona-treated PET) whose surface has been subjected to general corona treatment is about 50 Dyne, which exceeds the above upper limit of 40 Dyne. Further, as mentioned above, the surface wettability index of the fluorine-based film conventionally commonly used as a mold release film is usually about 20 Dyne, which is less than the above lower limit.

As mentioned above, conventionally, the releasability of the sealing film from the heating plate, etc. of the laminator during thermal lamination processing was determined by placing a separately prepared release film on the heating plate, etc. in advance. It was guaranteed by keeping it. The release film that was preferably used in this case was, for example, one coated with a release agent such as silicone to improve the release properties, that is, a surface treatment to adjust the release properties. The mold release film was widely used. However, if these release films with improved release properties are used as the release film 121 of the release film-integrated sealing material 1, the resin film forming the sealing film 111 made of olefin resin. If they are integrated during film formation, the adhesion between the layers is insufficient, and delamination is likely to occur frequently from the edges of the laminate forming the multilayer film. On the other hand, when the above-mentioned "surface-untreated polyethylene terephthalate resin film" is used as the resin film constituting the release film 121, the occurrence of such delamination can be sufficiently prevented, and The necessary mold releasability can be maintained.

Further, it is preferable that the release surface 122 of the release film 121 has a surface roughness: Rz (JIS B 0601-2001) of 80 nm or more. Surface roughness: When Rz is less than 80 nm, when the resin film constituting the sealing film 111 and the resin film constituting the release film 121 are integrated in roll-to-roll production equipment, Wrinkles and meandering are likely to occur, and by performing the minute shaping treatment as described above, these defects during manufacturing can be sufficiently prevented. In addition, in the conventional single release film, the molding treatment performed to improve the release property is usually a process such that the surface roughness of the release surface: Rz (JIS B 0601-2001) exceeds 500 nm. However, in the release surface 122 of the release film integrated sealing material 1, the surface roughness: Rz is at most 500 nm or less in order to maintain the necessary interlayer strength of the multilayer film. It is preferable to stop at

[Method for manufacturing release film integrated sealing material for self-luminous display]
The release film-integrated encapsulant of the present invention includes a film-forming process in which the encapsulant composition for forming each layer is melt-formed into a sheet, and laminated by heat-pressing each of the formed sheets. It can be manufactured through a lamination process for integration. This melt molding can be performed by various molding methods commonly used for conventional thermoplastic resins, such as injection molding, extrusion molding, blow molding, compression molding, and rotational molding. Each of these steps can be performed continuously online, for example, in a roll-to-roll type production facility as shown in FIG.

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 in which the above-mentioned process is performed by a roll-to-roll production facility 50. This is what is shown. In this roll-to-roll type production equipment 50, the molten resin forming the sealing film 111 is extruded from the T-die 51, and is nipped between the rubber roll 541 and the embossing roll 542 to form the sealing film. A film-like resin base material 111a constituting 111 is molded. At that time, the film-like resin base material 121a constituting the release film 121 is also fed out between the rubber roll 541 and the embossing roll 542 from the first paper feed roll 52, and both base materials are pressed together. integrated by. Further, at this time, other functional films 131a are also supplied from the second paper feed roll 53 as needed and integrated in the same manner. Each integrated base material passes through a cooling roll 543 and is wound up onto a paper discharge roll 54 as an integrated laminate.

In the release film integrated sealing material 1 of the present invention, the surface roughness of the surface (release surface) of the release film 121 (film-like resin base material 121a constituting the release film 121) is set to Rz 80 nm or more. By holding the resin base material 111a constituting the sealing film 111 and the resin base material 121a constituting the release film 121, minimal slipperiness is maintained and roll-to-roll production is possible. In equipment, it is possible to reduce the occurrence of fine wrinkles and meandering when guide rolls such as the rubber roll 541 and the embossing roll 542 run between the rolls, which are likely to occur in the process of laminating and integrating. If the surface roughness is less than 80 nm, there will be less slippage between the guide roll and the film, and if meandering or the like occurs, wrinkles will easily appear, and the process of laminating and integrating may become difficult.

<Method for manufacturing self-luminous display>
[Manufacturing method of LED module]
The LED module 30 for a self-luminous display constituting the micro LED display device 100 includes a wiring board 20 on which the LED elements 10 are mounted and a release film-integrated sealing material 1 on the side of the sealing film 111. This can be obtained through a thermal lamination process in which the laminate is laminated in such a manner that its surface covers the wiring board 20, and the laminate is placed on a heating plate of a laminator and then heat-pressed and integrated.

In this thermal lamination process, as shown in FIGS. 5 and 6, the above-described laminate is heated directly or auxiliarily on the side of the release film 121 of the release film-integrated sealing material 1 on the heating plate 41 of the laminator 40. This can be done by placing the laminate with the plate 42 interposed therebetween and, in this state, applying a vacuum to press the laminate restraining plate 43 onto the laminate. The auxiliary heating plate 42 is an auxiliary member arranged to compensate for the lack of surface smoothness of the heating plate 41 made of an iron plate or the like, and is usually a glass plate such as blue plate glass that has thermal conductivity and surface smoothness. is used. In this specification, the term "heating plate" refers not only to a heating plate made up of only the heating plate 41, but also to a laminate consisting of both of these when an auxiliary heating plate 42 is laminated on the heating plate 41. shall be considered as a "heating plate".

In detail, the above-mentioned 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). I will do it. At this time, normally, a release film integrated sealing material 1 is prepared that is wider than the wiring board 20 on which the LED element 10 is mounted, so that the sealing film 111 matches the module size when integrated. In order to obtain an appropriate size, the release film 121 is subjected to a process of cutting off unnecessary ends of the sealing film 111 in such a manner that the release film 121 is half-cut.

In the sealing film 111 of the release film-integrated sealing material 1 that has undergone the heat lamination process in this way, the olefin resin forming the same layer exhibits sufficient moldability, and the LED element 10 is formed. It adheres closely to the mounted wiring board 20 with good adhesion strength.

[Method for manufacturing self-luminous display]
By further laminating and integrating the display panel 2 with the LED module 30 that can be obtained by the above manufacturing method by adhesive bonding or the like, the micro LED display device 100 shown in FIG. 2 or a similar layered structure can be obtained. Various types of self-luminous display bodies can be manufactured.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples.

In a roll-to-roll production facility as shown in FIG. 7, a release film-integrated sealing material according to the present invention was test-manufactured by the above-described manufacturing method.

<Manufacture of release film integrated sealing material of Example>
(Sealing film)
The following resin composition for a sealing film was extruded using a φ30 mm extruder and a film molding machine having a 200 mm width T-die at an extrusion temperature of 210° C., a take-off speed of 1.1 m/min, and a film thickness of 150 μm.

(Resin composition for sealing film)
To 100 parts by mass of the following base resin, 5 parts by mass of Additive Resin 1 (weathering agent masterbatch) and 20 parts by mass of Additive Resin 2 (silane-modified polyethylene resin) were mixed to form the release film of the example. A sealing material composition was prepared for forming a sealing film of an integrated sealing material.
Base resin 1
: Metallocene-based linear low-density polyethylene resin (M-LLDPE) having 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 (weathering agent masterbatch)
: KEMISTAB62 (HALS): 0.6 parts by mass for 100 parts by mass of a low-density polyethylene resin having a density of 0.919 g/cm ³ and an MFR of 3.5 g/10 min at 190°C. KEMISORB12 (UV absorber): 3.5 parts by mass. KEMISORB79 (UV absorber): 0.6 parts by mass.
Additive resin 2 (silane modified polyethylene resin)
: 5 ^parts by mass of vinyltrimethoxysilane and a radical generator (reactive A silane-modified polyethylene resin obtained by mixing with 0.15 parts by mass of dicumyl peroxide as a catalyst), melting and kneading at 200°C. This additive resin 2 has a density of 0.901 g/cm ³ and an MFR of 1.0 g/10 min.

(Release film)
The following resin film for a release film was integrated by pressing the resin film constituting the release film with the sealing film melt-extruded as described above.
(Resin film for release film)
Polyethylene terephthalate (PET) film with a melting point of 260°C, thickness 50 μm. The wettability index of the surface of this resin film measured according to JIS K 6768 was 30 Dyne.

<Manufacture of release film integrated sealing material of comparative example>
The mold release film integrated sealing of the comparative example was carried out under the same conditions as the example, except that the following general-purpose mold release film, which has been processed to improve mold release properties, was used as the resin film constituting the mold release film. manufactured the material.

(General purpose release film)
Polyethylene terephthalate (PET) film with a melting point of 260°C, thickness 50 μm. However, this is a "resin film with surface release treatment" whose surface has been treated with silicone release treatment. The wettability index of the surface of this resin film measured according to JIS K 6768 was 18 Dyne.

<Evaluation example 1: Adhesion strength between films>
The adhesion strength (N /15mm) was measured. The results are shown in Table 1.
(Adhesion test)
In the release film-integrated sealing material cut to a width of 15 mm, the release film in close contact with the sealing film was vertically peeled (50 mm/min) using a peel tester (Tensilon Universal Tester RTF-1150-H). ) Test is conducted to measure the adhesion strength (N/15 mm) at the interface between both films.

<Evaluation Example 2: Ease of handling before thermal lamination>
Regarding the release film-integrated encapsulating materials of Examples and Comparative Examples, we tested the ease of handling before thermal lamination by manually placing each encapsulating material into a laminator, and evaluated the ease of handling during the process. The ease of handling before thermal lamination was sensory evaluated based on whether unnecessary delamination occurred. The work was performed separately by five workers, and the evaluation criteria were as follows. The evaluation results are listed in Table 1 as "ease of handling".
(Evaluation criteria)
A: During the manual process described above, no peeling between the sealing film and the release film occurred during the work by any of the workers.
B: During the manual process described above, peeling between the sealing film and the release film occurred during the work by one or less workers.
C: During the above manual process, peeling between the sealing film and the release film occurred during the work by two or more workers.

<Evaluation Example 3: Ease of peeling after thermal lamination>
In addition, it is possible to manufacture an LED module using the mold release film-integrated sealing material of the example using an existing laminator, and to use the above-mentioned sealing film as a sealing material, and also to manufacture the above-mentioned "general-purpose mold release film". The production of an LED module using the LED module as an independent mold release material without being integrated with the sealing film was carried out on a trial basis by the above-mentioned [LED module production method]. As a result, there were no problems with the peelability of the sealing material after thermal lamination, and the sealing film (sealing material) could be "smoothly removed" from the release film (mold release material). It was confirmed that it can be done.

From the above test manufacturing results of the LED module and the test and evaluation results in Table 1, the release film-integrated sealing material of the present invention can be used in the thermal lamination process performed in the manufacturing process of self-luminous displays. It can be seen that it is possible to avoid the loss of smoothness of the surface of the sealing material that occurs when using a release film, and the deterioration in quality of the self-luminous display that is caused by this.

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

Claims (5)

A sealing material for a self-luminous display,
It is a multilayer film formed by laminating a sealing film and a release film,
The sealing film uses an olefin resin as a base resin,
The release film has a melting point of 220°C or more and 270°C or less,
The surface of the peeling surface, which is the surface on the interface side with the sealing film, has a wettability index according to JIS K 6768 of 25 Dyne or more and 35 Dyne or less,
A release film-integrated sealing material, wherein 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 that is in close contact with the sealing film is vertically peeled using a peel tester (Tensilon Universal Tester RTF-1150-H). (50 mm/min) to measure the adhesion strength at the interface between both films. The release film-integrated sealing material according to claim 1, wherein the release film has a surface roughness: Rz of a peeling surface, which is a surface on the interface side with the sealing film, of 80 nm or more and 500 nm or less . _{The release film is a polyethylene terephthalate resin film,
The polyethylene terephthalate resin film is a surface-untreated polyethylene terephthalate resin film whose peeling surface, which is the surface on the interface side with the sealing film, has not been subjected to surface treatment for adjusting adhesion and mold releasability. The release film integrated sealing material according to claim 1 or 2 . The release film integrated sealing material according to any one of claims 1 to 3, wherein the base resin of the sealing film is a polyethylene resin having a density of 0.870 g/cm 3 or more and 0.930 g/cm 3 or less. A release film integrated sealing material according to any one of claims 1 to 4 ,
A light emitting module in which a plurality of light emitting elements are mounted on a wiring board;
A laminate made up of layers of
It includes a thermal lamination process in which the components are integrated by heat and pressure bonding while placed on a heating plate made of metal and/or glass,
The heat-compression bonding of the LED module is performed by directly placing the release film of the release film-integrated sealing material constituting the laminate on the heating plate without intervening another release film. Production method.}

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