JP2019179913A - Sealing material sheet for self-luminous type display and self-luminous type display using the same - Google Patents

Abstract

To solve the problem in which: there has been demanded development of a sealing material sheet specialized to be suitable for the application of various self-luminous type displays, such as a micro LED television that is increasingly expected as a next-generation display; to provide a sealing material sheet that is particularly excellent in suitability as a self-luminous type display, such as a micro LED television.SOLUTION: A sealing material sheet for a self-luminous type display that is a resin sheet that contains an olefin resin as a base resin, the sealing material sheet having a Vicat softening point of more than 60°C and 90°C or less, and an MFR at 190°C of 0.1 g/10 min or more and less than 12.0 g/10 min.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sealing material sheet for a self-luminous display and a self-luminous display using the same.

  Development of a self-luminous display body typified by a micro LED television is advancing as a next-generation display device that can replace various liquid crystal display devices (Patent Document 1).

  In this self-luminous display body, a sealing material sheet for protecting the light emitting element is laminated on the light emitting surface side surface of the LED module in which the light emitting element such as the LED element is mounted on the wiring board. (Patent Document 2).

  Here, the encapsulant sheet for electronic devices disclosed in Patent Document 2 is widely assumed to be applied to various electronic devices including solar cells, and the Vicat softening point is 60 ° C. or less. Particularly preferably, it is required to be in a low temperature range of 30 to 50 ° C. or lower. This is intended to “exhibit high adhesiveness by thermocompression in a short time” as described in the document. Also, in the past, the Vicat softening point is within the above-mentioned low temperature range in order to ensure sufficient embedding property (molding property) of the sealing material sheet to the unevenness of the surface of the electronic device having various surface shapes. Was considered preferred.

  However, in the process of developing the above-mentioned micro LED TV, the surface of the electronic device to be covered with the encapsulant sheet has only minute irregularities such as the light emitting surface of the LED module constituting the micro LED TV. In addition, when the film thickness uniformity of the sealing material after hot press processing is required at a higher level in each stage than in the case of a solar cell module or the like in order to maintain image quality There has been a suspicion that a sealing material sheet having a Vicat softening point in the low temperature range as described above is not necessarily optimal.

  When the unevenness of the target surface to be covered with the encapsulant sheet is minute, from the viewpoint of molding properties, it is not necessary to limit the biquad softening point to the low temperature range (60 ° C. or less) as described above. On the surface, rather than the above-mentioned merit as described in Patent Document 2 (thermocompression can be completed in a short time), the total productivity and quality stability decrease due to the occurrence of blocking of the sealing material sheet Becomes easier to manifest.

  In addition, when the Vicat softening point of the encapsulant sheet is in the above low temperature range, it is necessary to add a crosslinking agent in order to ensure sufficient heat resistance of the encapsulant sheet, and the material cost of the encapsulant sheet There is also a problem that the productivity is lowered due to an increase in the film forming temperature and the limitation of the film forming temperature.

  Under such circumstances, it has been desired to develop a sealing material sheet that is specialized as preferred for various self-luminous display applications, such as micro LED televisions that are increasingly expected as next-generation display devices. .

JP 2018-14481 A JP 2014-148484 A

  This invention is made | formed in view of the above situations, and it aims at providing the sealing material sheet which is especially excellent in the suitability | suitability for self-light-emitting display bodies, such as a micro LED television.

  As a result of intensive research, the inventors have defined the Vicat softening point of the encapsulant sheet for electronic devices in a high temperature range different from the conventional one, and the MFR is in a specific low MFR range. By maintaining, it has been found that the above-mentioned problems can be solved and a sealing material sheet that is particularly excellent in suitability for a self-luminous display such as a micro LED TV can be obtained. Specifically, the present invention provides the following.

  (1) A resin sheet having an olefin-based resin as a base resin, having a Vicat softening point of more than 60 ° C. and 90 ° C. or less, and an MFR at 190 ° C. of 0.1 g / 10 min to 12.0 g / 10 min The sealing material sheet for self-luminous type display bodies which is less than.

  According to the invention of (1), in the encapsulant sheet for encapsulating an electronic device, the Vicat softening point of the base resin is specified in a higher temperature range than that of the conventional product, and the MFR of the resin is the same as in the past. Or a lower MFR range of less than that. According to this, in all of the blocking resistance in the manufacturing process of the sealing material sheet, the molding property at the time of hot press processing, the uniformity of the film thickness after the hot press processing and the suppression of the protrusion of the resin due to excessive flow, For a self-luminous display, a sealing material sheet at a particularly preferred level can be obtained.

  (2) The encapsulant sheet according to (1), wherein the MFR at 190 ° C. is less than 5.0 g / 10 min.

  In the sealing material sheet of (1), the Vicat softening point temperature of the invention of (2) is further suppressed to a lower MFR while maintaining the high temperature range. Thereby, the excessive flow at the time of the hot press processing of the sealing material sheet of (1) can be further suppressed, and the uniformity of the film thickness after the hot press processing can be maintained at a higher level.

  (3) The encapsulant sheet according to (2), wherein the MFR at 190 ° C. is less than 0.5 g / 10 min.

  In the invention of (3), the MFR is suppressed to an extremely low range while maintaining the Vicat softening point temperature in the above-mentioned high temperature range for the sealing material sheet of (2). Such a sealing material sheet can be obtained by so-called weak crosslinking treatment. Thereby, the excessive flow at the time of the hot press processing of the sealing material sheet of (1) can be further suppressed, and the uniformity of the film thickness after the hot press processing can be maintained at a very high level.

  (4) A plurality of light-emitting elements are stacked on the light-emitting element mounting surface side of the wiring board so as to cover the light-emitting element and the light-emitting module for the self-luminous display body mounted on the wiring board. A sealing material sheet, and a display panel laminated on a surface of the sealing material sheet, wherein the sealing material sheet is the sealing material according to any one of (1) to (3) A self-luminous display that is a sheet.

  According to the invention of (4), the sealing material sheet of any one of (1) to (3) enjoys the advantageous effects on blocking resistance, molding properties, and film thickness uniformity. Thus, a self-luminous display body having excellent productivity, durability, and optical characteristics can be obtained.

  (5) The self-luminous display according to (4), wherein the light-emitting element is an LED element.

  The invention of (5) is an application of the present invention to various self-luminous LED display devices represented by a micro LED television expected as the mainstream of next-generation monitors. Thereby, a self-luminous LED display device excellent in productivity, durability, and optical characteristics can be obtained.

  (6) The LED element has an LED light-emitting chip and a resin cover that covers the LED light-emitting chip, and the width and depth of the LED element are both 300 μm or less and the height is 200 μm or less. In addition, the self-luminous display according to (5), wherein an interval between the LED elements is 0.03 mm or more and 12.0 mm or less.

  In the invention of (6), the self-luminous display body of (5) is added to a high-definition dot matrix display device or the like in which LED elements are densely mounted by a chip-on-board method in which a large number of LED chips are directly mounted on a substrate. It is applied. Thereby, it is possible to obtain a high-definition LED display device that is excellent in productivity, durability, and optical characteristics.

  (7) The width and depth of the LED elements are both 50 μm or less, the height is 10 μm or less, and the interval between the LED elements is 0.05 mm or more and 5 mm or less (6 The self-luminous display body as described in).

  The invention of (7) has been developed in recent years, and is the one in which the self-luminous display body of (5) is applied to a “micro LED television” expected as a next-generation video display device. Thereby, it is possible to obtain an ultra-high definition LED display device that is excellent in productivity, durability, and optical characteristics.

  (8) Any one of (4) to (7), wherein the plurality of light emitting modules have a light emitting surface joined on the same plane, and the sealing material sheet is laminated on the light emitting surface. A self-luminous display body as described in 1.

  In the invention of (7), various LED modules including a micro LED TV are formed by joining a plurality of LED modules for a self-luminous display body constituted by using the sealing material sheet of (1) or (2). The screen size of the display body is increased. Since the sealing material sheet of (1) or (2) is excellent in surface smoothness after joining by thermal lamination, it does not cause deterioration of screen quality due to joining of the above-mentioned modules, and the self-luminous display body. Large screen can be flexibly performed.

  ADVANTAGE OF THE INVENTION According to this invention, the sealing material sheet especially preferable for various self-luminous type display body uses, such as a micro LED television, can be provided.

It is the top view of the image display surface of the self-light-emitting display body by which the sealing material sheet of this invention is laminated | stacked on the light emitting module (LED module) for self-light-emitting display bodies, and its partial enlarged plan view. It is sectional drawing showing the cross section of the AA part of FIG. It is a perspective view of the LED element which comprises the LED module for self-luminous type display bodies of FIG.

<Self-luminous display>
First, the “self-luminous display body” in this specification is a display device represented by the above-described micro LED television, and is a display device for visual information such as characters, images, and moving images. In this display device, a small number of light-emitting elements are mounted in a matrix on a wiring board, and each light-emitting element is selectively caused to emit light by a light-emission control unit connected to the light-emitting element, whereby the above-described visual information is It is a display device that can display directly on the display screen by blinking of the light emitting element.

  The self-luminous display body sealing material sheet (hereinafter, also simply referred to as “sealing material sheet”) of the present invention is an LED display that uses LED elements as light-emitting elements among the “self-luminous display bodies”. It can be particularly preferably used in the apparatus. In this case, the LED element is more preferably a “small-sized LED element”. In the present specification, the “small size 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 the LED light emitting chip. ) Means an LED element having a height of 300 μm or less and a height (H) of 200 μm or less (see FIG. 3).

  Further, regarding the size of the “small LED element”, the width and the depth are both preferably 50 μm or less, and the height is more preferably 10 μm or less. This size range is a standard size of an LED element mounted on a micro LED television which has been developed in recent years and is expected to become the mainstream of next-generation televisions. Hereinafter, in the present specification, the LED elements having a very small size having a width and a depth of 50 μm or less and a height of 10 μm or less are several thousand × several thousand thousand at a pitch of several μm to several tens of μm. Self-luminous displays that are arranged in a matrix with a number greater than or equal to the number are referred to as “micro LED display devices”.

  In the following, the present invention will be described while taking an embodiment in which the “self-luminous display body” is a “micro LED display device” as a particularly preferable specific example of various embodiments of the present invention. A detailed description will be given. However, the technical scope of the present invention is not limited to application only to the “micro LED display device”. This is a technique applicable to all “self-luminous display bodies” defined above.

[Micro LED display]
FIG. 1 is a front view of a micro LED display device 100 which is an embodiment of the self-luminous display of the present invention, and a partially enlarged view (100A) thereof. 2 is a cross-sectional view showing a cross section of the AA portion of FIG. 1, and is a drawing for explaining a layer configuration of the micro LED display device 100 shown in FIG. The micro LED display device 100 includes a self-luminous display device including an LED module 30 that is a light-emitting module for a self-luminous display body in which a large number of LED elements 10 as light-emitting elements are mounted on a wiring board 20. The light emission of each LED element 10 is individually controlled by light emission control means (not shown) such as an IC chip substrate that is separately bonded.

  Further, in the micro LED display device 100, the sealing material sheet 1 for a self-luminous display body is laminated on the mounting surface of the LED element 10 of the LED module 30 so as to cover the LED element 10. A display surface panel 2 such as various optical films and transparent protective glass is further laminated on the outer surface side of the sealing material sheet 1 (display surface side in the micro LED display device 100).

  Further, a plurality of LED modules 30 for self-luminous display bodies are joined in a matrix on the same plane, and the sealing material sheet 1 is laminated on the joined LED modules in the same manner as described above, thereby obtaining a large An LED module for a light emitting display and a large micro LED display device can be configured. In this case, the excellent uniformity of the film thickness after the hot pressing of the encapsulant sheet 1 maintains the uniformity of the display surface at the joint between the individual LED modules to be joined. This contributes to improving the image quality of the micro LED display device.

(Manufacturing method of micro LED display device)
The micro LED display device 100 is disposed on the wiring board 20 by the LED module 30 for the self-luminous display body in which the LED element 10 is mounted, the sealing material sheet 1, the display surface panel 2, and as necessary. It is possible to manufacture by laminating other optical members to be laminated and integrating the laminated body by hot pressing. In addition, it is preferable to join some laminated members beforehand with an adhesive agent before said hot press process as needed. The sealing material sheet 1 of the present invention exhibits sufficient molding properties at the time of hot press processing for integration as the final product, and is extremely excellent in film thickness uniformity after the hot press processing. It is characterized by.

(LED module for self-luminous display)
As shown in FIG. 2, the LED module 30 that is a light emitting module for a self-luminous display according to the present invention has the LED element 10 mounted on a wiring substrate 20 in which a wiring portion 22 is formed on a support substrate 21. Consists of.

  As shown in FIG. 2, the wiring substrate 20 is formed on the surface of the support substrate 21 in a form that can be electrically connected to the LED element 10, for example, a wiring portion 22 formed of a metal such as copper or another conductive member. This is a circuit board. The support substrate 21 may be a conventionally known glass epoxy hard substrate as an electronic circuit substrate, or may be made of a flexible resin such as polyethylene terephthalate, polyimide, or polyethylene naphthalate.

  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.

  The size of the LED module 30 is not particularly limited, but a diagonal length of about 50 inches to 200 inches is generally preferable from the viewpoint of cost performance. In addition, as described above, a plurality of LED modules 30 for self-luminous display bodies are joined in a matrix on the same plane to form a light-emitting surface of a self-luminous display body such as a large micro LED display device 100. can do. For example, 100 × 100 LED modules 30 with a diagonal length of 6 inches can be joined vertically and horizontally to form a micro LED television having a large screen with a diagonal length of 600 inches.

(LED element)
The LED element 10 that is mounted on the wiring board 20 and constitutes the LED module 30 for a self-luminous display 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. There have been proposed 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 element surface. The LED element 10 having any structure can be used in the LED display device 100 of the present invention. However, the LED element 10 has a small size like the LED element disclosed as “chip-shaped electronic component” in Japanese Patent Application Laid-Open No. 2006-339551. An LED element can be particularly preferably used. The LED element disclosed in the document is said to have a width × depth × height size of approximately 25 μm × 15 μm × 2.5 μm.

  The LED element 10 preferably includes an LED light emitting chip 11 and a resin cover 12 covering the LED light emitting chip 11. The resin cover 12 is made of an organic insulating material such as an epoxy resin, a silicon resin, or a polyimide resin. Among these, an epoxy resin is particularly preferably used. The resin cover 12 formed of epoxy resin not only protects the LED light-emitting chip 11 from physical impact, but also introduces it into 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 serves to increase the light emission efficiency of the LED element 10 by suppressing the total reflection of light. The sealing material sheet 1 is preferable as a sealing material to be mounted on the micro LED display device 100 in that the sealing material sheet 1 is formed of an olefin resin that is also excellent in adhesion to an epoxy resin.

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

  The self-luminous display of the present invention is an LED element comprising an LED light-emitting chip and a resin cover that covers the LED light-emitting chip, and the width and depth are both 50 μm or less, and the height An LED element with a very small size of 10 μm or less can be used more preferably. In this case, it is preferable that the arrangement interval of the LED elements is 0.03 mm or more and 100 mm or less. Such an LED element mounting mode is also a standard LED element mounting mode in a micro LED television.

(Sealant sheet for self-luminous display)
The sealing material sheet of the present invention is a resin sheet that can be particularly preferably used as a resin sheet that covers a small number of light-emitting elements and is laminated on a wiring board in a “self-luminous display”. Moreover, this sealing material sheet for self-luminous type display bodies is formed into a sheet-like member by forming a sealing material composition containing an olefin-based resin as a base resin. In addition, although the single-layer film may be sufficient as the sealing material sheet of this invention, the multilayer film comprised by the core layer and the skin layer arrange | positioned on both surfaces of a core layer may be sufficient. The multilayer film in the present specification is a film or sheet having a structure having at least one outermost layer, preferably a skin layer formed on both outermost layers, and a core layer which is a layer other than the skin layer. Say that.

  The thickness of this sealing material sheet should just be 50 micrometers or more and 1000 micrometers or less, it is preferable that they are 50 micrometers or more and 500 micrometers or less, and it is more preferable that they are 50 micrometers or more and 300 micrometers or less. In addition, when the LED element to be covered is an LED element having a very small size with a height of 10 μm or less, the thickness of the sealing material sheet is preferably 25 μm or more and 100 μm or less. When the thickness of the encapsulant sheet is 50 μm or more, the LED element can be sufficiently protected from external impact. On the other hand, when the thickness of the sealing material sheet is 1000 μm or less, sufficient molding properties can be exhibited. Specifically, the resin constituting the encapsulant sheet can sufficiently wrap around the irregularities on the surface of the LED module and perform good lamination without gaps during hot press processing with the LED element covered. . Moreover, in the self-luminous display after integration, the light transmittance of the sealing layer made of the sealing material sheet can be sufficiently secured.

  And this sealing material sheet has a Vicat softening point exceeding 60 degreeC and 90 degrees C or less, Preferably, they are 70 degreeC or more and 90 degrees C or less. By making the Vicat softening point of the encapsulant sheet exceed 60 ° C., the occurrence of blocking in the manufacturing process of the self-luminous display body using the encapsulant sheet is suppressed, and the productivity of the self-luminous display body is improved. It can contribute to improvement. Moreover, the molding property requested | required of the sealing material sheet for self-luminous type display bodies can be maintained by making this temperature range into 90 degrees C or less.

  More specifically, it is preferable that the Vicat softening point of the encapsulant sheet is more strictly optimized according to the melting point of the encapsulant sheet. Specifically, when the melting point of the encapsulant sheet is in a relatively low range of 50 ° C. to less than 70 ° C., the Vicat softening point is set to 60 to 70 ° C. in order to suppress excessive flow during hot press processing. It is preferable that the range is less than the range. When the melting point is in a relatively high range of 70 ° C. or higher, the Vicat softening point is preferably in the range of 70 ° C. to 90 ° C. in order to maintain good molding properties during hot pressing.

  In addition, the “Vicat softening point” of the sealing material sheet in the present specification is a sealing material obtained by forming a sealing material composition containing a resin component and other additives into a sheet by a molding method such as extrusion melt molding. The Vicat softening point at the stage after completion of sheet formation is a value measured based on ASTM D1525.

  Further, the sealing material sheet for the self-luminous display body has a melt mass flow rate (MFR) at 190 ° C. of the resin sheet constituting it of 0.1 g / 10 min or more and less than 12.0 g / 10 min, preferably 0.1 g / 10 min or more and less than 5.0 g / 10 min, more preferably 0.1 g / 10 min or more and less than 0.5 g / 10 min. By setting the MFR of the sealing material sheet to 0.1 g / 10 min or more, the molding property required for the sealing material sheet for the self-luminous display body can be provided.

  In addition, by making this MFR less than 12.0 g / 10 min, the uniformity of the film thickness of the sealing material sheet after hot pressing for integration as a self-luminous display device can be maintained at a very high level. Can do. In the self-luminous display body such as the micro LED display device 100, the sealing material sheet laminated on the light emitting surface side of the LED element is required to have a particularly uniform film thickness. This is because if the film thickness of the central part and the talk part of the encapsulant sheet is slightly different, the encapsulant sheet becomes a lens-like state, which has an undesired unfavorable influence on the display quality of the micro LED display device. Because it gives.

  In addition, when the MFR of the encapsulant sheet is less than 12.0 g / 10 min, the fluidity of the material resin composition is lowered, and there is an advantage that high-temperature film formation is possible at the time of sheet extrusion molding and productivity is improved. . Film formation at a high temperature makes it possible to reduce the torque of the extruder and facilitate sheet forming. In addition, in the case of film formation at a high temperature, it is possible to form a wide sheet by suppressing neck-in at the time of forming the sheet. It is difficult to generate and unevenness is hardly generated on the surface of the sheet, and a good appearance is easily obtained.

  In addition, when the MFR of the sealing material is 12.0 g / 10 min or more, it is necessary to prescribe crosslinking with a crosslinking agent or the like in order to provide heat-resistant creep resistance, and the conditions during hot press processing also depend on the MFR. It is necessary to individually set the press conditions. When the MFR of the sealing material is less than 12.0 g / 10 min, no prescription for crosslinking is required, and the setting of the press conditions can be made common. Also in these points, it is preferable that MFR of a sealing material sheet shall be less than 12.0 g / 10min.

  The “MFR” of the encapsulant sheet in the present specification is an encapsulant sheet obtained by forming an encapsulant composition containing a resin component and other additives into a sheet by a molding method such as extrusion melt molding. The MFR at the stage after completion of sheeting is a value measured under conditions of 190 ° C. and 2.16 kg load in accordance with JIS K7210. In addition, about MFR in case a sealing material sheet | seat is a multilayer film, it measures by the said process with the multilayer state in which all the layers were laminated | stacked integrally, and the obtained measured value is the said multilayer sealing material sheet. The MFR value is assumed.

  As the base resin of the encapsulant composition forming the encapsulant sheet, an olefin-based thermoplastic resin can be widely selected as long as the Vicat softening point and MFR are in the above ranges. Among these, a polyethylene resin such as a low density polyethylene resin (LDPE), a linear low density polyethylene resin (LLDPE), or a metallocene linear low density polyethylene resin (M-LLDPE) can be preferably used. In the present specification, the “base resin” refers to a resin having the largest content ratio among the resin components of the resin composition in the resin composition containing the base resin.

The density of the polyethylene resin used as the base resin of the sealant composition, as long 0.870 g / cm ³ or more 0.910 g / cm ³ or less, preferably, 0.895 g / cm ³ or more zero. 905 g / cm ³ or less. By setting the density of the base resin of the encapsulant composition to 0.910 g / cm ³ or less, the adhesion of the encapsulant sheet to the wiring substrate or the like can be maintained within a preferable range. Further, by setting the density to 0.890 g / cm ³ or more, the sealing material sheet can be provided with necessary and sufficient heat resistance without undergoing a crosslinking treatment.

  Here, the encapsulant sheet of the present invention is one of the features that is a thermoplastic encapsulant that does not require a crosslinking treatment after film formation, but such a “crosslinking treatment is unnecessary”. As the sealing material sheet, a “weakly crosslinking sealing material” obtained by weakly crosslinking a polyethylene-based sealing material composition can also be used. “Weak cross-linking” is a cross-linking technique related to the method for producing a sealing material disclosed in International Publication No. 2011/152314, and is very weak cross-linking while maintaining the gel fraction at 0%. Is a technique for forming a film of a sealing material composition while proceeding. In the present specification, a weakly crosslinked encapsulant formed through this weak crosslinking treatment is referred to as a “weakly crosslinked encapsulant”. The weakly cross-linking encapsulant has been subjected to the weak cross-linking treatment at the time of film formation, and the cross-linking agent does not substantially remain after the film formation. Therefore, a separate cross-linking process in the manufacturing process of the self-luminous display body is unnecessary.

This weakly cross-linking encapsulant uses a polyethylene resin with a density of 0.870 g / cm ³ or more and 0.890 g / cm ³ or less as a base resin, and is a seal for a light-receiving surface side encapsulant containing a very small amount of a crosslinking agent. The stopping material composition can be obtained by performing the above-described weak crosslinking treatment during film formation in the process of film formation by a conventionally known method.

  In the sealing material composition, a silane copolymer obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as a comonomer (hereinafter, also referred to as “silane-modified polyethylene resin”), if necessary. More preferably, each sealing material composition contains a certain amount. The silane-modified polyethylene resin is obtained by graft-polymerizing an ethylenically unsaturated silane compound as a side chain to a linear low density polyethylene resin (LLDPE) or the like as a main chain. Since such a graft copolymer has a high degree of freedom of silanol groups contributing to the adhesive force, the adhesion of the sealing material sheet 1 to other members in the solar cell module can be improved. The content of the silane-modified polyethylene resin in the encapsulant composition is 2% by mass or more and 20% by mass or less in the encapsulant composition for the core layer, and in the encapsulant composition for the skin layer, It is preferable that they are 5 mass% or more and 40 mass% or less. In particular, it is more preferable that the encapsulant composition for the skin layer contains 10% or more of silane-modified polyethylene. In addition, it is preferable that the silane modification amount in said silane modified polyethylene resin is about 1.0 mass% or more and 3.0 mass% or less. The preferable content range of the silane-modified polyethylene resin in the sealing material composition is based on the premise that the silane-modified amount is within this range, and should be finely adjusted as appropriate according to the variation of the modified amount. Is desirable.

  The silane-modified polyethylene resin can be produced, for example, by a method described in JP-A-2003-46105. By using the resin as a component of a sealing material composition for a solar cell module, strength and durability are improved. In addition, it has excellent weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, yield resistance, and other characteristics, and is also affected by manufacturing conditions such as thermocompression bonding for manufacturing solar cell modules. Therefore, it is possible to manufacture solar cell modules that have extremely excellent heat-fusibility, are stable and low-cost, and are suitable for various applications.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

<Manufacture of sealing material sheet for self-luminous display>
The following sealing material composition prepared for each example and comparative example was extruded at a extrusion temperature of 210 ° C. and a take-off speed of 1.1 m / min using a φ30 mm extruder and a film molding machine having a T die having a width of 200 mm. Then, it was formed into a sheet with a film thickness of 400 μm, and the sealing material sheets of the examples and comparative examples were manufactured. In addition, about the cooling roll and rubber roll just under T-die, the cooling roll used the cooling roll of chromium plating finishing with surface roughness Rz1.5micrometer, and the rubber roll used the silicone rubber roll of hardness 70 degree | times.

(Sealing material sheet of Example 1 (1-1 to 1-2))
The following base resin 1 is mixed in an amount of 5 parts by mass of the following additive resin 1 (weathering agent masterbatch) and 20 parts by mass of the additive resin 2 (silane-modified polyethylene resin) with respect to 100 parts by mass. It was set as the sealing material composition for shape | molding the sealing material sheet of 1 (1-1 to 1-2).
Base resin 1
: Metallocene 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 at 190 ° C. of 2.0 g / 10 min.
Additive Resin 1 (Weatherproof Masterbatch)
: Density 0.919 g / cm ³ , MFR at 190 ° C. of 3.5 g / 10 min of low density polyethylene resin 100 parts by mass KEMISTAB62 (HALS): 0.6 parts by mass. KEMISORB 12 (UV absorber): 3.5 parts by mass. KEMISORB 79 (UV absorber): 0.6 parts by mass.
Additive resin 2 (Silane-modified polyethylene resin)
: 2 parts by mass of vinyltrimethoxysilane and a radical generator (reaction) with respect to 100 parts by mass of a metallocene linear low density polyethylene resin having a density of 0.900 g / cm ³ and an MFR of 2.0 g / 10 min Silane-modified polyethylene resin obtained by mixing 0.15 parts by mass of dicumyl peroxide as a catalyst), melting and kneading at 200 ° C. The density of the additive resin 2 is 0.901 g / cm ³ and the MFR is 1.0 g / 10 minutes.

(Sealing material sheet of Example 2 (2-1 to 2-2))
100 parts by mass of the following base resin 2 is mixed with 5 parts by mass of the additive resin 1 (weathering agent masterbatch) and 20 parts by mass of the additive resin 2 (silane-modified polyethylene resin), It was set as the sealing material composition for shape | molding the sealing material sheet of Example 2 (2-1 to 2-2).
Base resin 2: Metallocene linear low-density polyethylene resin (M-LLDPE) having a density of 0.898 g / cm ³ and an MFR at 190 ° C. of 3.5 g / 10 min.

(Sealing material sheet of Example 3 (3-1 to 3-2))
100 parts by mass of the following base resin 3 is mixed with 5 parts by mass of the additive resin 1 (weathering agent masterbatch) and 20 parts by mass of the additive resin 2 (silane-modified polyethylene resin), It was set as the sealing material composition for shape | molding the sealing material sheet of Example 3 (3-1 to 3-2).
Base resin 3: Metallocene linear low density polyethylene resin (M-LLDPE) having a density of 0.905 g / cm ³ and MFR at 190 ° C. of 3.5 g / 10 min.

(Sealing material sheet of Example 4 (4-1 to 4-2))
100 parts by mass of the following base resin 4 is mixed with 5 parts by mass of the additive resin 1 (weathering agent masterbatch) and 20 parts by mass of the additive resin 2 (silane-modified polyethylene resin), It was set as the sealing material composition for shape | molding the sealing material sheet of Example 4 (4-1 to 4-2).
Base resin 4: Metallocene linear low density polyethylene resin (M-LLDPE) having a density of 0.919 g / cm ³ and an MFR at 190 ° C. of 3.5 g / 10 min.

(Sealing material sheet of Example 5 (5-1 to 5-2))
With respect to 97 parts by mass of the following base resin 5, the additive resin 1 (weatherproof masterbatch 1-2) is 5 parts by mass, and the additive resin 2 (silane-modified polyethylene resin) is 5 parts by mass. It was set as the sealing material composition for shape | molding the sealing material sheet of Example 5 (5-1 to 5-2) which is mixed and is a weakly-crosslinking type sealing material sheet.
Base resin 5: 2,5-dimethyl-2,5-di (t-butyl par) with respect to 100 parts by mass of M-LLDPE pellets having 0.880 g / cm ³ and MFR at 190 ° C. of 3.5 g / 10 min. Compound pellets obtained by impregnating 0.041 parts by mass of oxy) hexane.

<Manufacture of sealing material>
Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples.

(Sealing material sheet of Comparative Example 1 (1-1 to 1-2))
The following base resin 6 is mixed at a ratio of 5 parts by mass with respect to 100 parts by mass of the additive resin 1 (weathering agent masterbatch) and 20 parts by mass of the additive resin 2 (silane-modified polyethylene resin), It was set as the sealing material composition for shape | molding the sealing material sheet of the comparative example 1 (1-1 to 1-2).
Base resin 6: Metallocene linear low-density polyethylene resin (M-LLDPE) having a density of 0.880 g / cm ³ and an MFR at 190 ° C. of 2.2 g / 10 min.

(Encapsulant sheet of Comparative Example 2)
100 parts by mass of the following base resin 7 is mixed with 3 parts by mass of the additive resin 1 (weathering agent masterbatch) and 10 parts by mass of the additive resin 2 (silane-modified polyethylene resin), A sealing material composition for molding the sealing material sheet of Comparative Example 2 was used.
Base resin 7: Metallocene linear low-density polyethylene resin (M-LLDPE) having a density of 0.910 g / cm ³ and an MFR at 190 ° C. of 15.0 g / 10 min.

(Encapsulant sheet of Comparative Example 3)
100 parts by mass of the following base resin 8 is mixed with 5 parts by mass of the additive resin 1 (weathering agent masterbatch) and 20 parts by mass of the additive resin 2 (silane-modified polyethylene resin), A sealing material composition for molding the sealing material sheet of Comparative Example 2 was used.
Base resin 8: Metallocene linear low-density polyethylene resin (M-LLDPE) having a density of 0.913 g / cm ³ and an MFR at 190 ° C. of 2.4 g / 10 min.

<Vicat softening point of encapsulant sheet>
The Vicat softening point of each sealing material sheet of Examples and Comparative Examples was measured based on ASTM D1525. The results are shown in Table 1.

<MFR of encapsulant sheet>
MFR of each sealing material sheet of an Example and a comparative example was measured on condition of 190 degreeC and a 2.16kg load based on JISK7210. The results are shown in Table 1.

<Evaluation Example 1: Blocking resistance>
About each sealing material sheet of an Example and a comparative example, blocking resistance was evaluated with the following test methods.
[Blocking resistance test]
(Test method)
The blocking property of each sealing material sheet of Examples and Comparative Examples was measured using a blocking tester of CO-201 permanent strain tester (constant load type) manufactured by Tester Sangyo Co., Ltd. according to ASTM D395. Using a large test piece 29 mmφ, a load of 5 kg was applied to form a shape in which the cooling roll surface side and the rubber roll surface side at the time of film formation were combined, and each sealing material sheet was cut to a size of 5 × 5 cm, And after blocking for 48 hours in a wet oven at 40 ° C. and 90%, the blocking state after 24 hours at 23 ° C. and 50% was confirmed.
(Evaluation criteria)
A: It peeled without applying force to peeling.
B: It peeled by applying force when peeling.
C: It was observed that a part of one sealing material laminated on the peeling surface was transferred to the other side and adhered as a result of peeling by applying a force when peeling.
The evaluation results are shown in Table 1 as “blocking resistance”.

<Evaluation Example 2: Molding Property>
About each sealing material sheet of an Example and a comparative example, the molding property with respect to various uneven surfaces was evaluated with the following test methods.
[Molding test module creation]
Sample 1 (denoted “small” in the table of module irregularities in Table 1)
: LED module in which LED elements with a micro size of 25 μm width × 15 μm depth × 2.5 μm height are arranged on the surface of a 200 × 300 mm glass epoxy wiring board at a pitch of 2 mm are prepared. A sealing material sheet of any of the comparative examples of each example having a thickness of 300 μm was laminated on the arrangement surface, and further, 50 μm ethylene tetragonal treated on one side as a surface protective film on the sealing material sheet. Fluoroethylene (ETFE) film is laminated and vacuum laminating is performed using a vacuum laminator for manufacturing solar cell modules under conditions of a temperature of 150 ° C., a vacuuming time of 5 minutes, a press holding time of 10 minutes, and an upper chamber pressure of 70 KPa. Then, a molding property test module (Sample 1) was produced.
Sample 2 (denoted as “small” in the table of module irregularities in Table 1)
: The molding property test module (with the same material and method as sample 1) except that the size of the LED element is 100 μm width × 200 μm depth × 100 μm height and the arrangement pitch is 10 mm. Sample 2) was prepared.
[Molding test]
Each of the above test modules was visually observed, and molding characteristics were evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: Completely follows the unevenness of the LED element arrangement surface facing the sealing material sheet. No void formation was observed.
B: Up to 3 bubbles within 2 mm ² were observed.
C: LED does not completely follow the unevenness of the LED element arrangement surface where a part of the encapsulant sheet faces, and the LED
A part of poor lamination (gap) was formed in the vicinity of the element.
The evaluation results are shown in Table 1 as “molding properties”.

<Evaluation Example 3: Film thickness uniformity>
About each sealing material sheet of an Example and a comparative example, about the uniformity of film thickness after the vacuum lamination performed by the above-mentioned molding test, the film thickness uniformity by the following test methods using each of the above test modules Was measured and evaluated.
[Thickness uniformity test]
A structure in which 50 μm untreated ETFE is laminated as a release film on the front and back of each sealing material sheet of Examples and Comparative Examples cut to 30 × 30 cm, and then 30 × 30 cm of 3 mm thick glass is laminated on the front and back. The laminate was subjected to vacuum laminating treatment under the same conditions as in Evaluation Example 2. After cooling, the glass and ETFE are peeled off, and the thickness of the sealing material is measured with a digital film thickness meter at the center part and at a location of 2 cm from the corner toward the center. The film thickness uniformity was evaluated according to the standard.
(Evaluation criteria)
A: The film thickness difference between the central part and the part 2 cm from the corner is less than 12 microns (3%).
B: The film thickness difference between the central part and the part 2 cm from the corner is 12 microns (3%) or more and less than 32 microns (8%).
C: The difference in film thickness between the central part and 2 cm from the corner is 32 microns (8%) or more.
The evaluation results are shown in Table 1 as “film thickness uniformity”.

  From Table 1, the encapsulant sheet of the present invention has sufficient molding properties for fine uneven surfaces and is excellent in film thickness uniformity, and is used for various self-luminous display bodies such as micro LED TVs. It turns out that it is suitable.

DESCRIPTION OF SYMBOLS 1 Sealant sheet 2 Display surface panel 10 LED element 11 LED light emitting chip 12 Resin cover 20 Wiring board 21 Support substrate 22 Wiring part 23 Solder layer 30 LED module for self-luminous display bodies 100, 100A, 100B Micro LED display device (Self-luminous display)

Claims (8)

  A resin sheet having an olefin resin as a base resin, having a Vicat softening point of more than 60 ° C. and 90 ° C. or less, and an MFR at 190 ° C. of 0.1 g / 10 min or more and less than 12.0 g / 10 min. A sealing material sheet for a self-luminous display.   The encapsulant sheet according to claim 1, wherein MFR at 190 ° C. is less than 5.0 g / 10 min.   The encapsulant sheet according to claim 2, wherein MFR at 190 ° C. is less than 0.5 g / 10 min. A light-emitting module for a self-luminous display body in which a plurality of light-emitting elements are mounted on a wiring board;
A sealing material that covers the light emitting element and is laminated on the mounting surface side of the light emitting element of the wiring board;
A display surface panel laminated on the surface of the sealing material,
The said sealing material is a self-luminous type display body which is the sealing material sheet in any one of Claim 1 to 3.   The self-luminous display body according to claim 4, wherein the light emitting element is an LED element. The LED element has an LED light emitting chip and a resin cover that covers the LED light emitting chip,
Both the width and depth of the LED element are 300 μm or less, and the height is 200 μm or less,
The self-luminous display according to claim 5, wherein an interval between the LED elements is 0.03 mm or more and 100 mm or less. The width and depth of the LED element are both 50 μm or less, and the height is 10 μm or less,
The self-luminous display according to claim 6, wherein an interval between the LED elements is 0.05 mm or more and 5 mm or less.   The self-light-emitting device according to any one of claims 4 to 7, wherein a plurality of the light-emitting modules have a light-emitting surface joined on the same plane, and the sealing material sheet is laminated on the light-emitting surface. Type indicator.

Images