Resin sheet and production method therefor

Abstract

To provide a resin sheet capable of suppressing warpage when forming a resin composition layer and enabling highly accurate foreign matter inspection of the resin composition layer using an automated optical appearance inspection device (AOI).SOLUTION: There is provided a resin sheet comprising a first film, a resin composition layer, and a second film or a glass plate, wherein the resin composition layer is located between the first film and the second film or between the first film and the glass plate, the first film comprises a monolayer plastic film as a substrate, a barrier layer formed on a surface of the plastic film, and a release layer formed on a surface of the barrier layer not in contact with the plastic film or on a surface of the plastic film not having the barrier layer, the first film is transparent, and the glass plate does not have the release layer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin sheet suitable for sealing electronic devices such as organic EL elements, solar cells, and touch panels having conductive substrates, and a method for producing the same. [Background technology]

[0002] BACKGROUND ART In order to protect electronic devices such as organic EL (electroluminescence) elements, solar cells, and touch panels having conductive substrates from moisture, the electronic devices are encapsulated using a resin sheet having a resin composition layer.

[0003] A resin sheet is usually composed of a support, a resin composition layer, and a cover film for protecting the resin composition layer (for example, Patent Document 1).

[0004] Furthermore, as a method for improving the moisture blocking properties of a resin sheet, it is known to blend semi-calcined hydrotalcite into the resin composition layer of the resin sheet (for example, Patent Document 2).

[0005] Paragraphs

[0015] and

[0016] of Patent Document 1 describe the use of a plastic film such as polyethylene terephthalate or a plastic film having a barrier layer as a support. However, paragraph

[0018] of the same document merely states that "Examples of a cover film for a resin sheet include plastic films similar to those used as a support," and does not describe the use of a plastic film having a barrier layer as a cover film.

[0006] When a highly moisture-permeable plastic film without a barrier layer is used as a cover film for a resin sheet, moisture may permeate through the cover film during storage of the resin sheet and be mixed into the resin composition layer. As a result, the resin sheet's ability to protect electronic devices from moisture may be reduced, and using such a resin sheet to seal an electronic device may shorten the life of the electronic device.

[0007] Furthermore, a resin sheet having a resin composition layer containing semi-calcined hydrotalcite can achieve high moisture-blocking properties due to the semi-calcined hydrotalcite, but semi-calcined hydrotalcite has the property of reversibly absorbing and releasing moisture. Therefore, in a resin sheet having a resin composition layer containing semi-calcined hydrotalcite, for example, the semi-calcined hydrotalcite absorbs moisture during storage of the resin sheet and then releases the absorbed moisture into the resin composition layer. Encapsulating an electronic device with a resin composition layer containing such released moisture may shorten the life of the electronic device. Furthermore, a resin sheet having a resin composition layer containing calcium oxide can also achieve high moisture-blocking properties, but because calcium oxide absorbs moisture irreversibly, calcium oxide absorbs moisture during storage of the resin sheet, resulting in the loss of moisture-blocking properties. Encapsulating an electronic device with such a resin composition layer may shorten the life of the device.

[0008] In view of the above, for example, Patent Document 3 discloses a resin sheet in which a plastic film having a barrier layer is used as a support, and a moisture-proof film is also used as a cover film, thereby suppressing water absorption by the resin composition layer. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-186843 [Patent Document 2] International Publication No. 2017 / 135112 [Patent Document 3] International Publication No. 2018 / 181426 Summary of the Invention [Problem to be solved by the invention]

[0010] However, highly moisture-resistant barrier films generally have a multilayer structure in which multiple thin inorganic films are laminated onto a plastic film by vapor deposition or the like, or metal foil is bonded to the film, or inorganic thin films and plastic films are alternately laminated. However, when used as a support for varnish coating, these films are prone to warping when heated. Furthermore, barrier films with metal foil or multilayer structures often contain air bubbles between layers. When inspecting the resin composition layer of a resin sheet for impurities using an automated optical inspection (AOI) system, the air bubbles are detected as defects, making accurate inspection difficult and reducing their suitability for AOI evaluation. Films made of aluminum foil and plastic film also have high moisture resistance, but they are also prone to warping and lack optical transparency, making them unsuitable for AOI inspection for impurities.

[0011] The present invention has been made in light of the above-mentioned circumstances, and its object is to provide a resin sheet that can suppress warping when forming a resin composition layer and enables foreign matter inspection of the resin composition layer with high accuracy using an optical automated inspection (AOI) device. [Means for solving the problem]

[0012] As a result of intensive research to solve the above problems, the present inventors have found that by using a transparent film having a single-layer plastic film as a substrate, a barrier layer formed on the plastic film surface, and a release layer formed on the barrier layer surface not in contact with the plastic film or on the plastic film surface not having the barrier layer as a film used as a support when forming a resin composition layer and to be peeled off when sealing an electronic device, and by using a film or glass plate having no release layer and high moisture permeability resistance as a layer to be incorporated into an electronic device, it is possible to suppress water absorption in the resin composition layer (particularly water absorption in a resin composition layer containing semi-calcined hydrotalcite or calcium oxide), enable foreign matter inspection of the resin composition layer of a resin sheet with high accuracy using an optical automated inspection (AOI) device, and suppress warping when forming the resin composition layer, thereby completing the present invention.

[0013] That is, the present invention has the following features. [1] A resin sheet having a first film, a resin composition layer, and a second film or a glass plate, a resin composition layer is present between the first film and the second film or between the first film and the glass plate; the first film has a single-layer plastic film as a substrate, a barrier layer formed on a surface of the plastic film, and a release layer formed on a surface of the barrier layer that is not in contact with the plastic film or on a surface of the plastic film that does not have the barrier layer; the first film is a transparent film, The water vapor transmission rate (hereinafter sometimes abbreviated as "WVTR") of the first film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24hr) or less, the release layer of the first film is in contact with the resin composition layer, The second film does not have a release layer, The water vapor permeability of the second film is 0.01 (g / m 2 / 24hr) The glass plate does not have a release layer; Resin sheet. [2] A film having a first film, a resin composition layer, and a second film, the resin composition layer is present between the first film and the second film; the first film has a single-layer plastic film as a substrate, a barrier layer formed on a surface of the plastic film, and a release layer formed on a surface of the barrier layer that is not in contact with the plastic film or on a surface of the plastic film that does not have the barrier layer; the first film is a transparent film, The water vapor permeability of the first film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24hr) or less, the release layer of the first film is in contact with the resin composition layer, The second film does not have a release layer, The water vapor permeability of the second film is 0.01 (g / m 2 / 24hr) [1] The resin sheet according to the present invention. [3] The resin sheet according to [1] or [2], wherein the thickness of the first film is 20 μm to 100 μm. [4] The resin sheet according to any one of [1] to [3], wherein the first film has a total light transmittance of 80% or more. [5] The resin sheet according to any one of [1] to [4], wherein the first film is a support for forming the resin composition layer. [6] The resin sheet according to any one of [1] to [5], wherein the resin composition layer contains a hygroscopic filler. [7] The resin sheet according to [6], wherein the hygroscopic filler is semi-calcined hydrotalcite or calcium oxide. [8] The resin sheet according to any one of [1] to [7], wherein the resin composition layer contains a polyolefin resin and / or an epoxy resin. [9] The resin sheet according to [8], wherein the resin composition layer contains a polyolefin resin.

[10] A method for producing a resin sheet according to any one of [1] to [9], comprising the steps of forming a resin composition layer on a release layer of a first film and laminating a second film or a glass plate to the resin composition layer.

[11] A method for producing an electronic device, comprising the steps of peeling off a first film from the resin sheet according to any one of [1] to [9], laminating a second film or a glass plate and the resin composition layer on the electronic device with the resin composition layer facing the electronic device, and sealing the electronic device with the second film or the glass plate and the resin composition layer.

[12] A resin sheet precursor having a first film, a resin composition layer, and a third film, the resin composition layer is present between the first film and the third film; the first film has a single-layer plastic film as a substrate, a barrier layer formed on the plastic film surface, and a release layer formed on the barrier layer surface or the plastic film surface; the first film is a transparent film, The water vapor permeability of the first film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24hr) or less, the third film has a release layer; The water vapor permeability of the third film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24hr) or less, the release layer of the first film and the release layer of the third film are in contact with the resin composition layer; Resin sheet precursor.

[13] The resin sheet precursor according to

[12] , wherein the resin composition layer contains semi-calcined hydrotalcite or calcium oxide as a hygroscopic filler.

[14] A method for producing a resin sheet precursor according to

[12] or

[13] , comprising the steps of forming a resin composition layer on the release layer of a first film and laminating a third film to the resin composition layer.

[15] The third film of the resin sheet precursor according to

[12] or

[13] is peeled off, and the resin sheet precursor has no release layer and its water vapor permeability is 0.01 (g / m 2 a resin sheet having a first film, the resin composition layer, and the second film or the glass plate, and a resin composition layer having a viscosity of less than 100 saturation / 24 hr; a resin sheet having a first film, the resin composition layer, and the second film or the glass plate; a resin sheet ... [Effects of the Invention]

[0014] According to the present invention, it is possible to suppress water absorption in the resin composition layer of a resin sheet (particularly water absorption in a resin composition layer containing semi-calcined hydrotalcite or calcium oxide), making it possible to inspect the resin composition layer of a resin sheet for foreign matter with a high accuracy using an optical automated inspection device (AOI), and suppressing warping when forming the resin composition layer. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described below based on preferred embodiments thereof. [Resin sheet] The resin sheet of the present invention has a first film, a resin composition layer, and a second film or a glass plate, and the resin composition layer is present between the first film and the second film or between the first film and the glass plate. The first film has a single-layer plastic film as a substrate, a barrier layer formed on a plastic film surface (preferably one surface of the plastic film), and a release layer formed on the barrier layer surface not in contact with the plastic film or on the plastic film surface not having the barrier layer (preferably the plastic film surface not having the barrier layer). The first film is a transparent film, and the water vapor permeability of the first film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24hr) or less, the release layer of the first film is in contact with the resin composition layer, the second film does not have a release layer, and the water vapor permeability of the second film is 0.01 (g / m 2 / 24 hr) or less, and the glass plate does not have a release layer. Note that, in JIS and other standards, those with a thickness of less than 0.25 mm are classified as films, and those with a thickness of more than 0.25 mm are classified as sheets, but the present invention is not limited to such classifications.

[0016] In the resin sheet of the present invention, the resin composition layer is present between the first film and the second film or between the first film and a glass plate. The first film is used as a support for forming the resin composition layer. The first film is also peeled off to expose the resin composition layer before laminating the resin sheet on an electronic device such as an organic EL element, and functions as a cover film. The first film has a release layer on the surface that comes into contact with the resin composition layer to facilitate peeling. The second film does not have a release layer because it is incorporated into the electronic device as a barrier film when sealing the electronic device and is not peeled off.

[0017] In a preferred embodiment of the present invention, the resin sheet has a first film, a resin composition layer, and a second film, with the resin composition layer being present between the first film and the second film.

[0018] <Film 1> In the resin sheet of the present invention, the first film has a single-layer plastic film as a substrate, a barrier layer formed on a surface of the plastic film (preferably one surface of the plastic film), and a release layer formed on the barrier layer surface that is not in contact with the plastic film or on the plastic film surface that does not have a barrier layer (preferably the plastic film surface that does not have a barrier layer), and the first film is a transparent film, and the water vapor permeability of the first film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24 hr) or less, and the release layer of the first film is in contact with the resin composition layer.

[0019] Examples of plastic films include single-layer plastic films made of polyolefins such as polyethylene and polypropylene (PP), polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), cycloolefin polymer (COP), and polyvinyl chloride. The plastic film is preferably a polyethylene terephthalate film, a cycloolefin polymer film, a polyethylene naphthalate film, or a polycarbonate film, and more preferably a polyethylene terephthalate film or a cycloolefin polymer film. The thickness of the substrate (single-layer plastic film) is preferably 10 to 100 μm, more preferably 15 to 90 μm, and even more preferably 20 to 80 μm.

[0020] By using a transparent single-layer plastic film as the substrate (preferably with the total light transmittance described below), foreign matter inspection (defect detection) of the resin composition layer becomes possible using an optical automated inspection (AOI) system. If the substrate is a plastic film with two or more layers, an adhesive layer is required between each layer, which can cause numerous defects and air bubbles in the substrate itself, making it impossible to accurately perform AOI detection of the resin composition layer. Furthermore, if the substrate is a plastic film with two or more layers, the linear thermal expansion coefficients of each layer are different, making it more likely that the substrate will warp when heated. Using a single-layer plastic film as the substrate reduces warping, enabling stable mass production.

[0021] Examples of the barrier layer in the first film include inorganic films such as silica vapor deposition films, silicon nitride films, and silicon oxide films, and organic-inorganic mixed films containing inorganic materials such as metal oxides and organic materials such as organic resins. The barrier layer has transparency as the first film, and its water vapor permeability is 0.01 (g / m 2 / 24hr) or more 1(g / m 2As long as the total thickness of the barrier layer in the first film is less than 0.01 (g / m² / 24 hr), the first film may have transparency and its water vapor permeability is 0.01 (g / m²). 2 / 24hr) or more 1(g / m 2 / 24 hr) or less, but is preferably 0.01 to less than 1 μm, more preferably 0.05 to 0.9 μm, and even more preferably 0.1 to 0.8 μm.

[0022] The barrier layer in the first film can be produced by laminating an inorganic film such as silicon oxide (silica), aluminum oxide, magnesium oxide, silicon nitride, silicon nitride oxide, SiCN, or amorphous silicon on the surface of a substrate (single-layer plastic film) by chemical vapor deposition (e.g., chemical vapor deposition using heat, plasma, ultraviolet light, vacuum heat, vacuum plasma, or vacuum ultraviolet light) or physical vapor deposition (e.g., vacuum deposition, sputtering, ion plating, laser deposition, or molecular beam epitaxy) (see, for example, JP 2013-108103 A). Alternatively, the barrier layer can be formed by applying a coating liquid composed of an inorganic substance such as a metal oxide and an organic resin to the surface of the substrate (single-layer plastic film) and drying it to form an organic-inorganic mixed film (see, for example, JP 4028353 A).

[0023] The release layer can be formed, for example, by applying a release agent to a substrate (single-layer plastic film) and drying it. The drying temperature after application of the release agent is, for example, 100 to 150°C, and the drying time is, for example, 5 to 120 minutes.

[0024] Examples of the release agent include silicone-based release agents, alkyd-based release agents, fluorine-based release agents, and olefin-based release agents. The release layer is preferably formed from a silicone-based release agent or an alkyd-based release agent. The thickness of the release layer is preferably 0.05 to 1 μm, more preferably 0.05 to 0.5 μm, and even more preferably 0.05 to 0.1 μm.

[0025] The thickness of the first film is preferably 20 to 100 μm, more preferably 20 to 90 μm, and even more preferably 20 to 80 μm, from the viewpoints of suppressing warping and winding the resin sheet into a roll.

[0026] The total light transmittance of the first film is preferably 80% or more, more preferably 82% or more, and even more preferably 85% or more, to enable foreign matter inspection (defect detection) of the resin composition layer using an optical automated inspection (AOI) device. The total light transmittance can be measured, for example, in accordance with JIS K7361-1 "Test method for total light transmittance of plastic transparent materials, Part 1: Single beam method."

[0027] The water vapor permeability of the first film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24hr) or less. The WVTR is preferably 0.8 (g / m 2 / 24hr) or less, and more preferably 0.6 (g / m 2 / 24hr) or less. 2 / 24hr) or more, and more preferably 0.1 (g / m 2 / 24hr) or more. This WVTR is a value measured by the method described in the Examples below. Furthermore, since the first film is peeled off and discarded before sealing the electronic device, if the WVTR is within this range, it is possible to simultaneously suppress the water absorption of the resin composition layer during storage and reduce costs. 2If the WVTR is less than 1 (g / m / 24hr), the thickness of the inorganic film increases, or multiple inorganic film layers are provided in a multi-layer structure, resulting in a large total thickness of the inorganic film in the film, making warping more likely to occur. 2 By setting the WVTR to 1 (g / m / 24 hr) or less, the life of the moisture blocking performance of the resin composition layer can be extended. 2 If the time exceeds 24 hours, the hygroscopic filler contained in the resin composition layer will absorb water vapor present in the atmosphere, and the original performance will not be exhibited.

[0028] In the present invention, the first film is used as a support when a resin composition varnish is applied and dried to form a resin composition layer, and is peeled off when sealing an electronic device. That is, the first film is used as a support for coating the resin composition varnish. If a highly moisture-resistant barrier film is used as a support for varnish coating, warping is likely to occur during heating, and there is a risk that the barrier layer will be damaged during coating, reducing its performance for sealing electronic devices. Furthermore, if the second film has a multilayer structure, AOI will detect air bubbles in the laminated substrate, making it less suitable for AOI evaluation of the resin composition layer. Furthermore, if the barrier layer is a metal foil, the resin composition layer cannot be evaluated by AOI due to its lack of optical transparency. Furthermore, glass plates are fragile when thin, and difficult to roll when thick, making them difficult to apply to coating equipment and therefore difficult to use as a support for coating. These issues can be resolved by using the first film as a support when forming the resin composition. In addition, even when the first film is used as a support for forming the resin composition layer, the barrier layer may be damaged, but the first film is ultimately peeled off and does not remain on the electronic device, so there is no problem with the sealing performance of the electronic device. Furthermore, it is cost-prohibitive to use a highly moisture-resistant barrier film or glass plate as a layer that is peeled off and discarded.

[0029] <Second Film> In the resin sheet of the present invention, the second film is a film that is incorporated into the electronic device as a barrier film when sealing the electronic device, does not have a release layer, and has a water vapor permeability of 0.01 (g / m 2 The second film may be a film having the same transparency as the first film, or may not have transparency.

[0030] The WVTR of the second film is preferably 0.005 (g / m 2 / 24hr) or less, and more preferably 0.001 (g / m 2 / 24hr) or less, and particularly preferably 0.0005 (g / m 2 The lower limit of the WVTR of the second film is not particularly limited, and a lower value is preferable, and the lower limit is 0 (g / m 2 This WVTR is a value measured by the method described in the Examples below.

[0031] The second film is preferably a film having a substrate and a barrier layer, where the substrate refers to the portion of the film other than the barrier layer.

[0032] The substrate may be a single-layer film or a laminated film. For example, it may have a laminated structure in which plastic films are laminated using an adhesive. There are no particular limitations on the adhesive, and commercially available adhesives can be used. Examples of the substrate include plastic films such as polyolefins such as polyethylene and polypropylene (PP), polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), cycloolefin polymer (COP), and polyvinyl chloride. The plastic film may be of one type or two or more types. The substrate is preferably a polyethylene terephthalate film, a cycloolefin polymer film, a polyethylene naphthalate film, or a polycarbonate film, and more preferably a polyethylene terephthalate film or a cycloolefin polymer film. The thickness of the substrate (the thickness of the entire substrate when the substrate has a laminated structure, or the total thickness of the substrate portion when the second film has a multilayer structure of an inorganic film and a substrate) is preferably 10 to 150 μm, more preferably 15 to 125 μm, and even more preferably 20 to 100 μm.

[0033] Examples of the barrier layer in the second film include metal foils (e.g., aluminum foils, copper foils), inorganic films such as silica vapor deposition films, silicon nitride films, and silicon oxide films, and organic-inorganic mixed films containing inorganic materials such as metal oxides and organic materials such as organic resins. The barrier layer may be composed of multiple inorganic film layers. Alternatively, the barrier layer may be composed of organic and inorganic materials. The second film may have a multilayer structure in which inorganic films and substrates are alternately laminated. In particular, when the inorganic films are formed by chemical vapor deposition or physical vapor deposition, a multilayer structure in which inorganic films and substrates are alternately laminated is preferred to prevent cracking of the inorganic films. When metal foils are used as the barrier layers in the second film, the total thickness of the barrier layers is preferably 15 μm to 100 μm, more preferably 20 μm to 90 μm, and even more preferably 25 μm to 80 μm. When the barrier layer is other than a metal foil (for example, an inorganic film or an organic-inorganic mixed film formed by chemical vapor deposition or physical vapor deposition), the total thickness of the barrier layer in the second film is preferably 1 to 10 μm, more preferably 1.5 to 8 μm, and even more preferably 2 to 5 μm.

[0034] WVTR is 0.01 (g / m 2 / 24hr) or less, especially the second film with a WVTR of 0.0005 (g / m 2The second film having a life of 1000 hours (1000 hours / 24 hours) or less can be produced, for example, by laminating an inorganic film such as silicon oxide (silica), aluminum oxide, magnesium oxide, silicon nitride, silicon nitride oxide, SiCN, or amorphous silicon on the surface of a substrate by chemical vapor deposition (e.g., chemical vapor deposition using heat, plasma, ultraviolet light, vacuum heat, vacuum plasma, or vacuum ultraviolet light) or physical vapor deposition (e.g., vacuum deposition, sputtering, ion plating, laser deposition, or molecular beam epitaxy) (see, for example, JP 2016-185705 A, JP 5719106 A, JP 5712509 A, JP 5292358 A, etc.). Alternatively, it can be formed by applying a coating liquid composed of an inorganic substance such as a metal oxide and an organic resin to the surface of a substrate (single-layer plastic film) and drying it to form an organic-inorganic mixed film (see, for example, JP 4028353 A, etc.). In addition, the WVTR is 0.01 (g / m 2 / 24hr) or less, especially the second film with a WVTR of 0.0005 (g / m 2 Examples of the second film having a film thickness of 1 / 24 hr or less include metal foil such as US foil, aluminum foil, and copper foil, and second films produced by bonding a substrate and a metal foil together with an adhesive.

[0035] The second film may be a commercially available product, such as "PET AL1N30" manufactured by Toyo Aluminum Co., Ltd., "X-BARRIER" manufactured by Mitsubishi Plastics, Inc., "Belear" manufactured by Reikosha, or "3EC-III" manufactured by Mitsui Kinzoku Co., Ltd.

[0036] The thickness of the second film is preferably 10 to 150 μm, more preferably 15 to 125 μm, and even more preferably 20 to 100 μm, from the viewpoints of ease of handling and winding the resin sheet into a roll.

[0037] In one embodiment of the present invention, a glass plate can be used instead of the second film. That is, the resin sheet of the present invention has a first film, a resin composition layer, and a glass plate, with the resin composition layer being present between the first film and the glass plate. The glass plate is incorporated into the electronic device as a barrier layer when sealing the electronic device, and does not have a release layer. The thickness of the glass plate is preferably 10 to 1000 μm, more preferably 50 to 900 μm, and even more preferably 100 to 800 μm. A glass plate having a thickness within this range is preferable because it is easy to handle. When the resin sheet is to be wound into a roll as a product form, the thickness of the glass plate is preferably 200 μm or less, more preferably 100 μm or less. When the glass plate is too thick to be wound, it can be made into sheets. Alternatively, instead of a glass plate (or a second film), a resin sheet precursor product using the third film described below can be sold, transported, stored, etc., and before use, the third film can be peeled off and a glass plate (or a second film) can be attached to it to produce a resin sheet. The water vapor permeability of a glass plate is usually 0.01 (g / m 2 / 24hr) and is less than 0.005 (g / m 2 / 24hr) or less, 0.001(g / m 2 / 24hr) or less, 0.0005(g / m 2 / 24hr) or less, 0(g / m 2 / 24hr).

[0038] <Resin composition layer> The resin constituting the resin composition layer used in the resin sheet of the present invention is not particularly limited as long as the effects of the present invention are exhibited, and examples thereof include thermoplastic resins (such as polyolefin-based resins), thermosetting resins (such as epoxy resins), etc. The resin composition layer preferably contains a polyolefin-based resin and / or an epoxy resin, and more preferably contains a polyolefin-based resin.

[0039] (Polyolefin resin) The polyolefin resin that can be used in the present invention is not particularly limited as long as it has an olefin-derived skeleton. For example, the polyolefin resin described in Patent Document 1 is a known example. The olefin is preferably a monoolefin having one olefinic carbon-carbon double bond and / or a diolefin having two olefinic carbon-carbon double bonds. Preferred examples of the monoolefin include α-olefins such as ethylene, propylene, 1-butene, isobutylene (isobutene), 1-pentene, 1-hexene, 1-heptene, and 1-octene. Preferred examples of the diolefin include 1,3-butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethylbutadiene. The polyolefin resin may contain one or more olefin-derived skeletons. Only one polyolefin resin may be used, or two or more polyolefin resins may be used in combination.

[0040] The polyolefin resin may be a homopolymer or a copolymer such as a random copolymer or a block copolymer. Examples of the copolymer include a copolymer of two or more olefins, and a copolymer of an olefin with a non-conjugated diene, styrene, or other monomer other than an olefin. Examples of preferred copolymers include an ethylene-non-conjugated diene copolymer, an ethylene-propylene copolymer, an ethylene-propylene-non-conjugated diene copolymer, an ethylene-butene copolymer, a propylene-butene copolymer, a propylene-butene-non-conjugated diene copolymer, a styrene-isobutylene copolymer, and a styrene-isobutylene-styrene copolymer.

[0041] Examples of polyolefin resins include isobutylene-modified resins described in WO 2011 / 62167 and styrene-isobutylene-modified resins described in WO 2013 / 108731.

[0042] The polyolefin resin is preferably a polybutene resin or a polypropylene resin. Here, "polybutene resin" refers to a resin in which the main unit (the unit with the largest content) among all olefin monomer units constituting the polymer is derived from butene, and "polypropylene resin" refers to a resin in which the main unit (the unit with the largest content) among all olefin monomer units constituting the polymer is derived from propylene.

[0043] When the polybutene resin is a copolymer, examples of the monomer other than butene include styrene, ethylene, propylene, isoprene, etc. When the polypropylene resin is a copolymer, examples of the monomer other than propylene include ethylene, butene, isoprene, etc.

[0044] From the viewpoint of imparting excellent physical properties such as adhesiveness and adhesive wet heat resistance, the polyolefin resin preferably contains a polyolefin resin having an acid anhydride group (i.e., a carbonyloxycarbonyl group (—CO—O—CO—)) and / or a polyolefin resin having an epoxy group. Examples of the acid anhydride group include a group derived from succinic anhydride, a group derived from maleic anhydride, and a group derived from glutaric anhydride. The polyolefin resin may have one or more types of acid anhydride groups. The polyolefin resin having an acid anhydride group can be obtained, for example, by graft-modifying a polyolefin resin with an unsaturated compound having an acid anhydride group under radical reaction conditions. Alternatively, the unsaturated compound having an acid anhydride group may be radically copolymerized with an olefin or the like. Similarly, the polyolefin resin having an epoxy group can be obtained, for example, by graft-modifying a polyolefin resin with an unsaturated compound having an epoxy group, such as glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, or allyl glycidyl ether under radical reaction conditions. Furthermore, an unsaturated compound having an epoxy group may be radically copolymerized with an olefin, etc. One or more types of polyolefin resins may be used, and a polyolefin resin having an acid anhydride group and a polyolefin resin having an epoxy group may be used in combination.

[0045] The polyolefin resin having an acid anhydride group is preferably a polybutene resin having an acid anhydride group or a polypropylene resin having an acid anhydride group, and the polyolefin resin having an epoxy group is preferably a polybutene resin having an epoxy group or a polypropylene resin having an epoxy group.

[0046] The concentration of acid anhydride groups in the polyolefin resin having acid anhydride groups is preferably 0.05 to 10 mmol / g, more preferably 0.1 to 5 mmol / g. The concentration of acid anhydride groups is determined from the acid value, which is defined as the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of resin, as described in JIS K 2501. The amount of the polyolefin resin having acid anhydride groups in the polyolefin resin is preferably 0 to 70 mass%, more preferably 10 to 50 mass%.

[0047] The epoxy group concentration in the epoxy group-containing polyolefin resin is preferably 0.05 to 10 mmol / g, more preferably 0.1 to 5 mmol / g. The epoxy group concentration is determined from the epoxy equivalent weight obtained in accordance with JIS K 7236-1995. The amount of the epoxy group-containing polyolefin resin in the polyolefin resin is preferably 0 to 70 mass %, more preferably 10 to 50 mass %.

[0048] From the viewpoint of imparting excellent physical properties such as sealing performance, the polyolefin resin preferably contains both a polyolefin resin having an acid anhydride group and a polyolefin resin having an epoxy group. Such a polyolefin resin can form a crosslinked structure by reacting the acid anhydride group and the epoxy group by heating, thereby forming an encapsulating layer with excellent sealing performance. Although the crosslinked structure can be formed after encapsulation, for example, when the encapsulated object is heat-sensitive, such as an electronic device, it is desirable to encapsulate using a resin sheet and form the crosslinked structure when producing the resin sheet.

[0049] The ratio of the polyolefin resin having an acid anhydride group to the polyolefin resin having an epoxy group is not particularly limited as long as an appropriate crosslinked structure can be formed, but the molar ratio of the epoxy group to the acid anhydride group (epoxy group:acid anhydride group) is preferably 100:10 to 100:400, more preferably 100:25 to 100:350, and particularly preferably 100:40 to 100:300.

[0050] When a polyolefin resin having an epoxy group is used in the resin composition layer of the resin sheet of the present invention, a polyolefin resin having a functional group (excluding an acid anhydride group) capable of reacting with the epoxy group may be used. Examples of the functional group include a hydroxyl group, a phenolic hydroxyl group, an amino group, and a carboxyl group.

[0051] When a polyolefin resin having an acid anhydride group is used in the resin composition layer of the resin sheet of the present invention, a polyolefin resin having a functional group (excluding an epoxy group) capable of reacting with the acid anhydride group may be used. Examples of the functional group include a hydroxyl group, a primary or secondary amino group, a thiol group, and an oxetane group.

[0052] The number average molecular weight of the polyolefin resin is not particularly limited, but from the viewpoint of achieving good coating properties of the resin composition varnish and good compatibility with other components in the resin composition, it is preferably 1,000,000 or less, more preferably 750,000 or less, even more preferably 500,000 or less, even more preferably 400,000 or less, even more preferably 300,000 or less, particularly preferably 200,000 or less, and most preferably 150,000 or less. On the other hand, from the viewpoint of preventing cissing during coating of the resin composition varnish, exhibiting the sealing performance of the formed resin composition layer, and improving mechanical strength, the number average molecular weight is preferably 1,000 or more, more preferably 2,000 or more. The number average molecular weight in the present invention is measured by gel permeation chromatography (GPC) method (polystyrene equivalent). Specifically, the number average molecular weight according to the GPC method can be measured using a Shimadzu Corporation LC-9A / RID-6A measuring apparatus, a Showa Denko Corporation Shodex K-800P / K-804L / K-804L column, toluene or the like as a mobile phase at a column temperature of 40°C, and calculated using a calibration curve of standard polystyrene.

[0053] The polyolefin resin in the present invention is preferably amorphous from the viewpoint of suppressing a decrease in fluidity due to thickening of the varnish. Here, amorphous means that the polyolefin resin does not have a clear melting point, and for example, a polyolefin resin that does not show a clear peak when its melting point is measured by DSC (differential scanning calorimetry) can be used.

[0054] Next, specific examples of polyolefin resins will be described. Specific examples of polypropylene resins include "T-YP341" manufactured by Seiko PMC Co., Ltd. (glycidyl methacrylate-modified propylene-butene random copolymer, butene unit content per 100% by mass of propylene units and butene units: 29% by mass, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 155,000), "T-YP279" manufactured by Seiko PMC Co., Ltd. (maleic anhydride-modified propylene-butene random copolymer, butene unit content per 100% by mass of propylene units and butene units: 36% by mass, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 35,000), and "T-YP276" manufactured by Seiko PMC Co., Ltd. (glycidyl methacrylate-modified propylene-butene random copolymer, propylene units and butene units: 36% by mass, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 57,000), Seiko PMC's "T-YP312" (maleic anhydride-modified propylene-butene random copolymer, butene units: 29% by mass, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 60,900), and Seiko PMC's "T-YP313" (glycidyl methacrylate-modified propylene-butene random copolymer, butene units: 29% by mass, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 155,000).

[0055] Specific examples of polybutene resins include "HV-1900" (polybutene, number-average molecular weight: 2,900) manufactured by ENEOS Corporation (formerly "JXTG Energy"); "HV-300M" (maleic anhydride-modified liquid polybutene (modified "HV-300" (number-average molecular weight: 1,400)) manufactured by Toho Chemical Industry Co., Ltd., number-average molecular weight: 2,100, number of carboxy groups constituting the acid anhydride group: 3.2 / molecule, acid value: 43.4 mg KOH / g, acid anhydride group concentration: 0.77 mmol / g); "Opanol B100" (polyisobutylene, viscosity-average molecular weight: 1,110,000) manufactured by BASF; and "N50SF" (polyisobutylene, viscosity-average molecular weight: 400,000) manufactured by BASF.

[0056] Specific examples of styrene-isobutylene copolymers include Kaneka Corporation's "SIBSTAR T102" (styrene-isobutylene-styrene block copolymer, number average molecular weight: 100,000, styrene content: 30% by mass), Seiko PMC's "T-YP757B" (maleic anhydride-modified styrene-isobutylene-styrene block copolymer, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 100,000), and Seiko PMC's "T-YP766" (glycidyl methacrylate-modified styrene-isobutylene-styrene block copolymer, epoxy resin). Examples of such copolymers include "T-YP8920" manufactured by Seiko PMC (maleic anhydride-modified styrene-isobutylene-styrene copolymer, acid anhydride group concentration: 0.464 mmol / g, number average molecular weight: 35,800), and "T-YP8930" manufactured by Seiko PMC (glycidyl methacrylate-modified styrene-isobutylene-styrene copolymer, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 48,700).

[0057] The content of the polyolefin resin in the resin composition layer used in the resin sheet of the present invention is not particularly limited. However, from the viewpoint of the sealing performance and handling property of the resin composition layer, the content is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less, based on 100% by mass of the nonvolatile content of the resin composition layer.

[0058] (epoxy resin) Any epoxy resin can be used without limitation as long as it has two or more epoxy groups per molecule on average. Examples of epoxy resins include bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, biphenyl type epoxy resins, biphenyl aralkyl type epoxy resins, naphthol type epoxy resins, naphthalene type epoxy resins, bisphenol F type epoxy resins, phosphorus-containing epoxy resins, bisphenol S type epoxy resins, aromatic glycidylamine type epoxy resins (e.g., tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyl toluidine, diglycidyl aniline, etc.), alicyclic epoxy resins, aliphatic linear epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, epoxy resins having a butadiene structure, diglycidyl ethers of bisphenols, diglycidyl ethers of naphthalene diol, diglycidyl ethers of phenols, and diglycidyl ethers of alcohols, as well as alkyl-substituted, halides, and hydrogenated versions of these epoxy resins. The epoxy resin may be used alone or in combination of two or more kinds.

[0059] From the viewpoint of reactivity and the like, the epoxy equivalent of the epoxy resin is preferably 50 to 5,000, more preferably 50 to 3,000, even more preferably 80 to 2,000, still more preferably 100 to 1,000, even more preferably 120 to 1,000, and particularly preferably 140 to 300. The "epoxy equivalent" refers to the number of grams (g / eq) of resin containing 1 gram equivalent of epoxy groups, and is measured according to the method specified in JIS K 7236. The weight-average molecular weight of the epoxy resin is preferably 5,000 or less.

[0060] The epoxy resin may be either liquid or solid, and both liquid and solid epoxy resins may be used. Here, "liquid" and "solid" refer to the state of the epoxy resin at room temperature (25°C) and atmospheric pressure (1 atmosphere).

[0061] The amount of the epoxy resin is not particularly limited. When an epoxy resin is used, the amount is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and even more preferably 50 to 65% by mass, relative to 100% by mass of the nonvolatile content of the resin composition layer.

[0062] (hygroscopic filler) The resin composition layer used in the resin sheet of the present invention may contain a hygroscopic filler. Examples of the hygroscopic filler include calcium oxide, hydrotalcite, magnesium oxide, and molecular sieves. The hygroscopic filler may be used alone or in combination of two or more. The content of the hygroscopic filler is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, and even more preferably 0 to 20% by mass, relative to 100% by mass of the nonvolatile content of the resin composition layer. The hygroscopic filler is preferably calcium oxide.

[0063] Hydrotalcite can be classified into uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite.

[0064] The uncalcined hydrotalcite is a metal hydroxide having a layered crystal structure represented by, for example, natural hydrotalcite (Mg6Al2(OH) 16 CO3·4H2O), and is composed of, for example, a layer [Mg 1-X Al X (OH)2] X+ and an intermediate layer [(CO3) X / 2 ·mH2O] X- . The uncalcined hydrotalcite is a concept including hydrotalcite-like compounds such as synthetic hydrotalcite. Examples of the hydrotalcite-like compounds include those represented by the following formula (I) and the following formula (II).

[0065] [M<已翻译,保留原文 2+ <已翻译,保留原文 1-x M<已翻译,保留原文 3+ <已翻译,保留原文 x (OH)2]<已翻译,保留原文 x+ ·[(A<已翻译,保留原文 n- )<已翻译,保留原文 x / n ·mH2O]<已翻译,保留原文 x- (I) (In the formula, M<已翻译,保留原文 2+ represents a divalent metal ion such as Mg<已翻译,保留原文 2+ , Zn<已翻译,保留原文 2+ etc., M<已翻译,保留原文 3+ represents a trivalent metal ion such as Al<已翻译,保留原文 3+ , Fe<已翻译,保留原文<已翻译,保留原文 3+ etc., A<已翻译,保留原文 n- represents an n-valent anion such as CO3<已翻译,保留原文<0已翻译,保留原文 2- , Cl<已翻译,保留原文 - , NO3<已翻译,保留原文 - etc., 0 < x < 1, 0 ≤ m < 1, and n is a positive number.) In formula (I), M<已翻译,保留原文 2+ is preferably Mg<已翻译,保留原文 2+ , M<已翻译,保留原文 3+ is preferably Al<已翻译,保留原文 3+ , and A<已翻译,保留原文 n- is preferably CO3<已翻译,保留原文 2- .

[0066] M<已翻译,保留原文 2+ <已翻译,保留原文 x Al2(OH)<已翻译,保留原文 2x+6-nz (A<已翻译,保留原文 n- )<已翻译,保留原文 z ·mH2O (II) (In the formula, M2+ is Mg 2+ , Zn 2+ represents a divalent metal ion such as A n- is CO3 2- , Cl - , NO3 - represents an n-valent anion such as, where x is a positive number of 2 or more, z is a positive number of 2 or less, m is a positive number, and n is a positive number. In formula (II), M 2+ is preferably Mg 2+ and A n- is preferably CO3 2- is.

[0067] Semi-calcined hydrotalcite refers to a metal hydroxide having a layered crystal structure in which the amount of interlayer water is reduced or eliminated, and is obtained by calcining uncalcined hydrotalcite. When explained using a compositional formula, "interlayer water" refers to "H2O" described in the compositional formula of the above-mentioned uncalcined natural hydrotalcite and hydrotalcite-like compounds.

[0068] On the other hand, calcined hydrotalcite is obtained by calcining uncalcined or semi-calcined hydrotalcite, and refers to a metal oxide having an amorphous structure in which not only interlayer water but also hydroxyl groups have disappeared through condensation dehydration.

[0069] Uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished by their saturated water absorption. The saturated water absorption of semi-calcined hydrotalcite is 1% by mass or more and less than 20% by mass. On the other hand, the saturated water absorption of uncalcined hydrotalcite is less than 1% by mass, and the saturated water absorption of calcined hydrotalcite is 20% by mass or more.

[0070] The "saturated water absorption" refers to the rate of mass increase relative to the initial mass when 1.5 g of a measurement sample (for example, semi-calcined hydrotalcite) is weighed out on a balance, the initial mass is measured, and the sample is allowed to stand for 200 hours in a small environmental test chamber (SH-222 manufactured by Espec Corporation) set at atmospheric pressure, 60°C, and 90% RH (relative humidity), and is calculated using the following formula (i): Saturated water absorption rate (mass%) = 100 × (mass after moisture absorption – initial mass) / initial mass (i) It can be found by:

[0071] The saturated water absorption of the semi-calcined hydrotalcite is preferably 3% by mass or more and less than 20% by mass, and more preferably 5% by mass or more and less than 20% by mass.

[0072] Furthermore, uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished by the rate of weight loss on heat measured by thermogravimetric analysis. The rate of weight loss on heat of semi-calcined hydrotalcite at 280°C is less than 15% by mass, and the rate of weight loss on heat of semi-calcined hydrotalcite at 380°C is 12% by mass or more. On the other hand, the rate of weight loss on heat of uncalcined hydrotalcite at 280°C is 15% by mass or more, and the rate of weight loss on heat of calcined hydrotalcite at 380°C is less than 12% by mass.

[0073] Thermogravimetric analysis can be performed using a Hitachi High-Tech Science TG / DTA EXSTAR6300 by weighing 5 mg of hydrotalcite into an aluminum sample pan, leaving the pan open without a lid, in a nitrogen atmosphere with a flow rate of 200 mL / min, and heating from 30°C to 550°C at a rate of 10°C / min. The thermal weight loss rate can be calculated using the following formula (ii): Thermogravimetric reduction rate (mass%) = 100 × (mass before heating - mass when reaching the specified temperature) / mass before heating (ii).

[0074] Uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished by the peaks and relative intensity ratios measured by powder X-ray diffraction. Semi-calcined hydrotalcite exhibits a split peak or a peak with a shoulder formed by combining two peaks in powder X-ray diffraction at 2θ of approximately 8 to 18°. The relative intensity ratio (low-angle diffraction intensity / high-angle diffraction intensity) between the diffraction intensity of the peak or shoulder appearing on the low-angle side (= low-angle diffraction intensity) and the diffraction intensity of the peak or shoulder appearing on the high-angle side (= high-angle diffraction intensity) is 0.001 to 1,000. Uncalcined hydrotalcite, on the other hand, has only one peak near 8 to 18°, or the relative intensity ratio between the diffraction intensity of the peak or shoulder appearing on the low-angle side and the peak or shoulder appearing on the high-angle side falls outside the aforementioned range. Calcined hydrotalcite does not have a characteristic peak in the 8 to 18° region, but has a characteristic peak at 43°. Powder X-ray diffraction measurements were performed using a powder X-ray diffractometer (PANalytical, Empyrean) under the following conditions: CuKα (1.5405 Å) anticathode, voltage: 45 V, current: 40 mA, sampling width: 0.0260°, scan rate: 0.0657° / s, diffraction angle range (2θ): 5.0131–79.9711°. Peak search was performed using the peak search function of the software provided with the diffractometer under the following conditions: minimum significance: 0.50, minimum peak tip: 0.01°, maximum peak tip: 1.00°, peak base width: 2.00°, method: minimum second derivative.

[0075] The BET specific surface area of ​​semi-calcined hydrotalcite is 1 to 250 m 2 / g is preferred, and 5 to 200m 2 These BET specific surface areas can be calculated by the BET method using a specific surface area measuring device (Macsorb HM Model 1210, manufactured by Mountech Co., Ltd.) by adsorbing nitrogen gas onto the surface of a sample and then using the BET multipoint method.

[0076] The particle size of the semi-calcined hydrotalcite is preferably 1 to 1,000 nm, more preferably 10 to 800 nm. These particle sizes are the median sizes of the particle size distribution determined on a volume basis by laser diffraction / scattering particle size distribution measurement (JIS Z 8825).

[0077] The semi-calcined hydrotalcite can be surface-treated with a surface treatment agent. Examples of the surface treatment agent that can be used for the surface treatment include higher fatty acids, alkylsilanes, and silane coupling agents, with higher fatty acids and alkylsilanes being preferred. One or more types of surface treatment agents can be used.

[0078] Commercially available semi-calcined hydrotalcites can be used, such as "DHT-4C" and "DHT-4A-2" manufactured by Kyowa Chemical Industry Co., Ltd.

[0079] Commercially available calcium oxide products can be used, such as "QC-X" manufactured by Inoue Lime Industry Co., Ltd., "Moistop #10" manufactured by Sankyo Flour Milling Co., Ltd., "HAL-G," "HAL-J," and "HAL-F" manufactured by Yoshizawa Lime Industry Co., Ltd., and "CaO Nano Powder" manufactured by Filgen.

[0080] In the present invention, a mixture containing calcium oxide may be used as the hygroscopic filler. Examples of such mixtures include calcined dolomite (a mixture containing calcium oxide and magnesium oxide). Calcined dolomite is available from Yoshizawa Lime Industry Co., Ltd., for example.

[0081] The particle size of calcium oxide and the particle size of a mixture containing calcium oxide (hereinafter sometimes referred to as "calcium oxide, etc.") are preferably 0.03 to 10 μm, more preferably 0.05 to 5 μm, and even more preferably 0.1 to 3 μm, respectively, in order to prevent calcium oxide, etc. from damaging the electronic device during the sealing process and to increase the interfacial bonding strength between calcium oxide, etc. and the resin. These particle sizes are the median diameters of the particle size distribution obtained by laser diffraction / scattering particle size distribution measurement (JIS Z 8825) on a volume basis.

[0082] Calcium oxide is a hygroscopic inorganic particle essential for achieving high moisture-blocking properties. Unlike semi-calcined hydrotalcite, calcium oxide absorbs moisture irreversibly, and its moisture absorption performance declines once it absorbs moisture. Therefore, it is necessary to form a resin composition layer at high temperatures in a short time. On the other hand, when a first film is used as the substrate, which is a plastic film with two or more layers, the linear thermal expansion coefficients of each layer differ, resulting in more pronounced warping of the substrate when exposed to high temperatures. As described above, these problems can be solved by using a single-layer plastic film as the substrate for the first film and appropriately setting the thickness and WVTR (barrier property) of the first film.

[0083] (tackifier) The resin composition layer used in the resin sheet of the present invention may further contain a tackifier. The tackifier, also known as a tackifier, is a component that imparts adhesiveness to the composition. The tackifier is not particularly limited, and preferred examples include terpene resins, modified terpene resins (hydrogenated terpene resins, terpene-phenol copolymer resins, aromatic-modified terpene resins, etc.), coumarone resins, indene resins, and petroleum resins (aliphatic petroleum resins, hydrogenated alicyclic petroleum resins, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, alicyclic petroleum resins, dicyclopentadiene petroleum resins and hydrogenated versions thereof).

[0084] Examples of commercially available products that can be used as tackifiers include the following: Terpene resins include YS Resin PX and YS Resin PXN (both manufactured by Yasuhara Chemical Co., Ltd.); aromatic modified terpene resins include YS Resin TO and TR series (both manufactured by Yasuhara Chemical Co., Ltd.); hydrogenated terpene resins include Clearon P, Clearon M, and Clearon K series (both manufactured by Yasuhara Chemical Co., Ltd.); terpene-phenol copolymer resins include YS Polystar 2000, Polystar U, Polystar T, Polystar S, and Mighty Ace G (both manufactured by Yasuhara Chemical Co., Ltd.); and hydrogenated alicyclic petroleum resins include Examples of such petroleum resins include the Escorez 5300 series and 5600 series (both manufactured by ExxonMobil Corporation), aromatic petroleum resins include ENDEX 155 (manufactured by Eastman Co.), aliphatic aromatic copolymer petroleum resins include Quintone D100 (manufactured by Zeon Corporation), alicyclic petroleum resins include Quintone 1325 and Quintone 1345 (both manufactured by Zeon Corporation), and saturated hydrocarbon resins include Alcon P100, Alcon P125, Alcon P140 and TFS13-030 (all manufactured by Arakawa Chemical Co., Ltd.).

[0085] The softening point of the tackifier is preferably 50 to 200° C., more preferably 90 to 180° C., and even more preferably 100 to 150° C., from the viewpoint of softening the resin composition layer in the lamination step and having the desired heat resistance. The softening point is measured by the ring and ball method in accordance with JIS K2207.

[0086] The tackifier may be used alone or in combination of two or more. There is no particular limitation on the content of the tackifier in the resin composition layer. However, when a tackifier is used from the viewpoint of maintaining good sealing performance of the resin composition layer, the content is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on 100% by mass of the nonvolatile content of the resin composition layer. On the other hand, when a tackifier is used from the viewpoint of having sufficient adhesiveness, the content is preferably 5% by mass or more, more preferably 10% by mass or more, based on 100% by mass of the nonvolatile content of the resin composition layer.

[0087] Petroleum resins are preferred from the viewpoints of adhesiveness, sealing performance, transparency, etc. of the resin composition layer. Examples of petroleum resins include aliphatic petroleum resins, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, and alicyclic petroleum resins. From the viewpoints of adhesiveness, sealing performance, compatibility, etc. of the resin composition layer, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, and alicyclic petroleum resins are more preferred. Furthermore, from the viewpoint of improving transparency, alicyclic petroleum resins are particularly preferred. As the alicyclic petroleum resin, aromatic petroleum resins that have been subjected to hydrogenation treatment can also be used. In this case, the hydrogenation rate of the alicyclic petroleum resin is preferably 30 to 99%, more preferably 40 to 97%, and even more preferably 50 to 90%. If the hydrogenation rate is too low, there is a tendency for problems such as reduced transparency due to coloration to occur, and if the hydrogenation rate is too high, there is a tendency for production costs to increase. The hydrogenation rate is determined by the ratio of hydrogen on the aromatic ring before and after hydrogenation. 1 It can be determined from the ratio of peak intensities in H-NMR. As the alicyclic petroleum resin, cyclohexane ring-containing hydrogenated petroleum resin and dicyclopentadiene-based hydrogenated petroleum resin are particularly preferred. One or more types of petroleum resins may be used in combination. The number average molecular weight Mn of the petroleum resin is preferably 100 to 2,000, more preferably 700 to 1,500, and even more preferably 500 to 1,000.

[0088] (hardening agent and / or hardening accelerator) The resin composition layer used in the resin sheet of the present invention may contain a curing agent and / or a curing accelerator (preferably a curing accelerator). The curing agent and the curing accelerator may be used alone or in combination of two or more. Examples of the curing agent include imidazole compounds, tertiary and quaternary amine compounds, dimethylurea compounds, organic phosphine compounds, primary and secondary amine compounds, etc. Examples of the curing accelerator include imidazole compounds, tertiary and quaternary amine compounds, dimethylurea compounds, organic phosphine compounds, etc.

[0089] Examples of the imidazole compound that is the curing agent and / or curing accelerator in the present invention include 1H-imidazole, 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6-(2'-undecylimidazolyl-(1'))-ethyl-s-triazine, 2-phenyl-4,5-bis(hydroxymethyl)imidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-phenylimidazole, 2-dodecyl ... Examples of the imidazole compound include decyl imidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6-(2'-methylimidazolyl-(1')-ethyl-s-triazine, and 2,4-diamino-6-(2'-methylimidazolyl-(1'))-ethyl-s-triazine isocyanuric acid adduct. Specific examples of the imidazole compound include Curesol 2MZ, 2P4MZ, 2E4MZ, 2E4MZ-CN, C11Z, C11Z-CN, C11Z-CNS, C11Z-A, 2PHZ, 1B2MZ, 1B2PZ, 2PZ, C17Z, 1.2DMZ, 2P4MHZ-PW, 2MZ-A, and 2MA-OK (all manufactured by Shikoku Chemicals Corporation).

[0090] The tertiary or quaternary amine compound used as the curing agent and / or curing accelerator in the present invention is not particularly limited, and examples thereof include quaternary ammonium salts such as tetramethylammonium bromide and tetrabutylammonium bromide; diazabicyclo compounds such as DBU (1,8-diazabicyclo[5.4.0]undecene-7), DBN (1,5-diazabicyclo[4.3.0]nonene-5), DBU-phenol salt, DBU-octylate salt, DBU-p-toluenesulfonate, DBU-formate, and DBU-phenol novolac resin salt; tertiary amines and salts thereof such as benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol (TAP); and dimethylurea compounds such as aromatic dimethylurea and aliphatic dimethylurea.

[0091] Examples of primary and secondary amine compounds useful as curing agents in the present invention include aliphatic amines such as diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, 1,3-bisaminomethylcyclohexane, dipropylenediamine, diethylaminopropylamine, bis(4-aminocyclohexyl)methane, norbornene diamine, and 1,2-diaminocyclohexane; alicyclic amines such as N-aminoethylpiperazine and 1,4-bis(3-aminopropyl)piperazine; and aromatic amines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and diethyltoluenediamine. Specific examples of primary and secondary amine compounds include Kayahard AA (manufactured by Nippon Kayaku Co., Ltd.: 4,4'-diamino-3,3'-dimethyldiphenylmethane).

[0092] Specific examples of the dimethylurea compound as the curing agent and / or curing accelerator in the present invention include aromatic dimethylureas such as DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and U-CAT3512T (manufactured by San-Apro Co., Ltd.), and aliphatic dimethylureas such as U-CAT3503N (manufactured by San-Apro Co., Ltd. Of these, aromatic dimethylureas are preferably used from the viewpoint of curability.

[0093] Examples of organic phosphine compounds as curing agents and / or curing accelerators in the present invention include triphenylphosphine, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tri-tert-butylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, triphenylphosphine triphenylborane, etc. Specific examples of organic phosphine compounds include TPP, TPP-MK, TPP-K, TTBuP-K, TPP-SCN, and TPP-S (manufactured by Hokko Chemical Industry Co., Ltd.).

[0094] The total content of the curing agent and curing accelerator in the resin composition layer is not particularly limited, but is preferably 5% by mass or less, more preferably 1% by mass or less, relative to 100% by mass of the nonvolatile content of the resin composition layer, from the viewpoint of preventing a decrease in the transparency of the sealing layer (resin composition layer). On the other hand, the total is preferably 0.0005% by mass or more, more preferably 0.001% by mass or more, relative to 100% by mass of the nonvolatile content of the resin composition layer, from the viewpoint of suppressing tackiness of the sealing layer.

[0095] The content of the curing accelerator in the resin composition layer is not particularly limited, but from the viewpoint of preventing a decrease in the transparency of the sealing layer (resin composition layer), it is preferably 5% by mass or less, more preferably 1% by mass or less, relative to 100% by mass of the nonvolatile content of the resin composition layer. On the other hand, from the viewpoint of suppressing tackiness of the sealing layer, the content is preferably 0.0005% by mass or more, more preferably 0.001% by mass or more, relative to 100% by mass of the nonvolatile content of the resin composition layer.

[0096] (plasticizer) The resin composition layer used in the resin sheet of the present invention may further contain a plasticizer. The use of a plasticizer can improve the flexibility and moldability of the resin composition layer. The plasticizer is not particularly limited, but a material that is liquid at room temperature is preferably used. Specific examples of plasticizers include mineral oils such as paraffinic process oil, naphthenic process oil, liquid paraffin, polyethylene wax, polypropylene wax, and Vaseline; vegetable oils such as castor oil, cottonseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, and olive oil; and liquid poly-α-olefins such as liquid polybutene, hydrogenated liquid polybutene, liquid polybutadiene, and hydrogenated liquid polybutadiene. Liquid poly-α-olefins are preferred as the plasticizer used in the present invention, with liquid polybutadiene being particularly preferred. Furthermore, from the standpoint of adhesiveness, liquid poly-α-olefins with a low molecular weight are preferred, with those with a weight-average molecular weight of 500 to 5,000, and more preferably 1,000 to 3,000, being preferred. These plasticizers may be used alone or in combination of two or more. Here, "liquid" refers to the state of the plasticizer at room temperature (25°C). When using a plasticizer, its content is preferably 50% by mass or less relative to 100% by mass of the nonvolatile content of the resin composition layer, so as not to adversely affect the electronic device.

[0097] (Other ingredients) The resin composition layer used in the resin sheet of the present invention may contain any component other than the above-mentioned components to the extent that the effect of the present invention is not impaired. Such components include, for example, resins other than the above-mentioned polyolefin resins and epoxy resins (e.g., urethane resins, acrylic resins, polyamide resins, etc.); thickeners such as Orben and Benton; silicone-based, fluorine-based, and polymer-based antifoaming or leveling agents; adhesion promoters such as triazole compounds, thiazole compounds, triazine compounds, and porphyrin compounds; etc.

[0098] The thickness of the resin composition layer used in the resin sheet of the present invention is preferably 3 to 100 μm, more preferably 5 to 90 μm, and even more preferably 10 to 80 μm. If the thickness of the resin composition layer is less than 3 μm, the adhesion of the resin sheet decreases and sealing cannot be achieved. If the thickness exceeds 100 μm, residues of the organic solvent used in the resin composition varnish are generated during the formation of the resin sheet, which may affect the electronic device during sealing.

[0099] [Resin sheet manufacturing method 1] One method for producing the resin sheet of the present invention includes the steps of forming a resin composition layer on the release layer of a first film and laminating a second film or a glass plate to the resin composition layer.

[0100] In a preferred embodiment of the present invention, the method for producing a resin sheet of the present invention includes the steps of forming a resin composition layer on the release layer of a first film and laminating a second film to the resin composition layer.

[0101] <Step of forming a resin composition layer on the release layer of the first film> The resin composition layer can be formed by applying a resin composition varnish onto the release layer of the first film using a die coater or the like, followed by drying. The resin composition varnish is prepared by mixing the components of the resin composition with an organic solvent using a kneading roller, a rotary mixer, or the like. The non-volatile content of the resin composition varnish is preferably 20 to 80% by mass, more preferably 30 to 70% by mass.

[0102] Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and aromatic mixed solvents such as solvent naphtha. Commercially available aromatic mixed solvents include "Swasol" (manufactured by Maruzen Oil Co., Ltd.) and "Ipsol" (manufactured by Idemitsu Kosan Co., Ltd.). Only one organic solvent may be used, or two or more organic solvents may be used in combination.

[0103] The varnish can be dried simply by heating. Heating may be carried out under normal pressure or under reduced pressure. The drying temperature and drying time can be appropriately set by a person skilled in the art depending on the components and organic solvent used. For example, the drying temperature is 80 to 170°C, and the drying time is 3 to 60 minutes. When the resin composition layer contains an epoxy resin, the drying temperature is preferably 80 to 100°C, and the drying time is preferably 5 to 90 minutes. When the resin composition layer does not contain an epoxy resin but contains an olefin-based resin, the drying temperature is preferably 80 to 170°C, and the drying time is preferably 5 to 60 minutes.

[0104] <Step of bonding a second film or a glass plate to the resin composition layer> A resin sheet can be produced by forming a resin composition layer on the release layer of a first film and then laminating a second film (preferably the barrier layer of the second film) or a glass plate to the resulting resin composition layer. For lamination, known devices such as a roll laminator, a press, or a vacuum pressure laminator can be used. Those skilled in the art can appropriately set lamination conditions (temperature, pressure, time, etc.).

[0105] In the present invention, the second film is a film that is incorporated into the electronic device as a barrier film when sealing the electronic device, and has a water vapor permeability of 0.01 (g / m 2 / 24 hr) (i.e., high moisture permeability resistance). When a barrier film with high moisture permeability resistance is used as a support for varnish coating, warping is likely to occur when heated, and there is a risk that the barrier layer will be damaged during coating, resulting in a decrease in performance for sealing electronic devices. Furthermore, when the second film has a multilayer structure, AOI detects air bubbles in the substrate of the laminated structure, making it less suitable for AOI evaluation of the resin composition layer. Furthermore, when the barrier layer is a metal foil, the resin composition layer cannot be evaluated by AOI because it is not light-transmitting. Furthermore, glass plates are difficult to use as support for coating because they are brittle when thin and difficult to roll when thick, making them difficult to apply to coating equipment. These problems can be solved by laminating a second film to a resin composition layer formed on the release layer of a first film according to the above-mentioned manufacturing method of the present invention. Note that even when the first film is used as a support for forming a resin composition layer, scratches may occur to the barrier layer, but the first film is ultimately peeled off and does not remain on the electronic device, so there is no problem with the sealing performance of the electronic device. Furthermore, highly moisture-resistant barrier films and glass plates are disadvantageous in terms of cost when used as layers that are to be peeled off and discarded.

[0106] [Resin sheet manufacturing method 2] Another method for producing a resin sheet of the present invention includes a step of forming a resin composition layer on the release layer of a first film, a step of bonding a third film to the resin composition layer, and a step of peeling off the third film and bonding a second film or a glass plate to the resin composition layer before sealing an electronic device, wherein the third film has a release layer and its water vapor permeability is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24 hr) or less, and the adhesive strength between the third film and the resin composition layer is lower than the adhesive strength between the first film and the resin composition layer.

[0107] In a preferred embodiment of the present invention, the method for producing a resin sheet of the present invention comprises the steps of forming a resin composition layer on a release layer of a first film, laminating a third film to the resin composition layer, and, prior to sealing of an electronic device, peeling off the third film and laminating a second film to the resin composition layer, wherein the third film has a release layer and its water vapor permeability is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24 hr) or less, and the adhesive strength between the third film and the resin composition layer is lower than the adhesive strength between the first film and the resin composition layer.

[0108] <Step of forming a resin composition layer on the release layer of the first film> This step is as explained in the above [Method 1 for producing a resin sheet].

[0109] <Step of bonding the third film to the resin composition layer> A resin sheet precursor can be produced by forming a resin composition layer on the release layer of a first film and then laminating the release layer of a third film to the resulting resin composition layer. For lamination, known devices such as a roll laminator, a press, or a vacuum pressure laminator can be used. Those skilled in the art can appropriately set the lamination conditions (temperature, pressure, time, etc.).

[0110] <Step of Peeling Off the Third Film and Bonding the Second Film or Glass Plate to the Resin Composition Layer> The third film can be peeled off by a method known to those skilled in the art. Because the adhesive strength of the third film to the resin composition layer is lower than that of the first film (i.e., the peel strength of the release layer of the third film is lower than that of the release layer of the first film), the third film is peeled off preferentially over the first film. A resin sheet can then be produced by laminating a second film (preferably with the barrier layer side of the second film in contact with the resin composition layer) or a glass plate to the exposed resin composition layer. For lamination, known equipment such as a roll laminator, a press, or a vacuum pressure laminator can be used. Those skilled in the art can appropriately determine the lamination conditions (temperature, pressure, time, etc.).

[0111] In manufacturing method 2, the peel strength of the release layer of the third film is smaller than that of the release layer of the first film. Specifically, the difference between the peel strength of the release layer of the third film and that of the first film [peeling strength of the release layer of the first film (mN / 25 mm) - peel strength of the release layer of the third film (mN / 25 mm)] is not particularly limited as long as it is within a range in which the third film is peeled preferentially over the first film, but is preferably 1 to 200 mN / 25 mm, more preferably 1 to 150 mN / 25 mm, and even more preferably 1 to 100 mN / 25 mm. Here, the peel strength of the release layer is a value measured by the method described in the Examples below.

[0112] [Resin sheet precursor] The present invention also relates to a resin sheet precursor having a first film, a resin composition layer, and a third film, wherein the resin composition layer is present between the first film and the third film, and the first film has a single-layer plastic film as a substrate, a barrier layer formed on a surface of the plastic film (preferably one surface of the plastic film), and a release layer formed on the surface of the barrier layer that is not in contact with the plastic film or on the surface of the plastic film that does not have the barrier layer (preferably the plastic film surface that does not have the barrier layer), and the first film is a transparent film, and the water vapor permeability of the first film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24hr) or less, the third film has a release layer, and the water vapor permeability of the third film is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 / 24 hr) or less, and the release layer of the first film and the release layer of the third film are in contact with the resin composition layer.

[0113] The first film and resin composition layer used in the resin sheet precursor of the present invention are as explained above in the resin sheet of the present invention.

[0114] The third film used in the resin sheet precursor of the present invention has a substrate and a release layer, and preferably further has a barrier layer formed on the substrate surface (preferably one surface of the substrate). Here, the substrate refers to the portion of the film other than the barrier layer. The release layer in the third film is formed on the substrate surface (preferably one surface of the substrate) when the film does not have a barrier layer, and when the film has a barrier layer, the release layer may be formed on either the barrier layer surface that is not in contact with the substrate or the substrate surface that does not have the barrier layer, and is preferably formed on the substrate surface that does not have the barrier layer.

[0115] The substrate and barrier layer are as described above in the second film of the resin sheet of the present invention, and the release layer is as described above in the first film of the resin sheet of the present invention.

[0116] The WVTR of the third film is preferably 0.01 (g / m 2 / 24hr) or more 0.8(g / m) 2 / 24 hr) or less. This WVTR is a value measured by the method described in the Examples below. Since the third film is peeled off and discarded before sealing the electronic device, if the WVTR is in this range, it is possible to simultaneously suppress the water absorption of the resin composition layer during storage and reduce costs.

[0117] WVTR is 0.01 (g / m 2 / 24hr) or more 1(g / m 2 The third film having a film thickness of 1 / 24 hr or less can be produced, for example, by vapor-depositing an inorganic film containing an inorganic substance such as silicon oxide (silica), aluminum oxide, magnesium oxide, silicon nitride, silicon nitride oxide, SiCN, or amorphous silicon onto the surface of the substrate as a barrier layer, or by applying a coating liquid containing a metal oxide and an organic resin having barrier properties to the substrate and drying the coating liquid (see, for example, JP 2013-108103 A and JP 4028353 A). The third film produced by such a method is a transparent film.

[0118] The third film may be a commercially available product, such as "Kurarista CI" manufactured by Kuraray Co., Ltd., "Techbarrier HX," "Techbarrier LX," and "Techbarrier L" manufactured by Mitsubishi Plastics, Inc., "IB-PET-PXB" manufactured by Dai Nippon Printing Co., Ltd., and "GL, GX series" manufactured by Toppan Printing Co., Ltd.

[0119] The thickness of the third film is preferably 20 to 100 μm, more preferably 20 to 90 μm, and even more preferably 20 to 80 μm. If the thickness of the third film is less than 20 μm, warping occurs in the step of forming the release layer. If the thickness exceeds 100 μm, the obtained resin sheet cannot be wound into a roll.

[0120] In one embodiment of the present invention, the resin sheet precursor of the present invention is used as the resin sheet precursor in the above-mentioned [Resin Sheet Manufacturing Method 2]. Therefore, the third film is peeled off before the second film or the glass plate is laminated to the resin composition layer, and functions as a cover film.

[0121] [Application] The resin sheet of the present invention can be used to seal electronic devices. The electronic devices are more preferably electronic devices that are vulnerable to moisture, such as organic EL devices and solar cells. That is, the resin sheet of the present invention can be suitably used to seal electronic devices that are particularly vulnerable to moisture, such as organic EL devices and solar cells.

[0122] [Sealing of electronic devices] The resin sheet of the present invention can be used to encapsulate an electronic device. Specifically, after peeling off the first film of the resin sheet to expose the resin composition layer, the exposed resin composition layer is placed on the electronic device side (i.e., the resin composition layer is in contact with the electronic device), and a second film or glass plate and the resin composition layer are laminated on the electronic device. The resin composition layer is cured as described below, and the electronic device is encapsulated with the second film or glass plate and the resin composition layer. The lamination method may be a batch method or a continuous method using a roll. In this way, an electronic device encapsulated with the resin sheet of the present invention can be produced.

[0123] In addition, the third film of the resin sheet precursor was peeled off, and the resin sheet precursor had no release layer and its water vapor permeability was 0.01 (g / m 2 Alternatively, a second film or a glass plate not having a release layer, having a shelf life of less than 1 / 24 hr, may be attached to the resin composition layer to obtain a resin sheet having a first film, a resin composition layer, and a second film or a glass plate, and then the first film of the resin sheet may be peeled off, and the second film or the glass plate and the resin composition layer may be laminated on the electronic device with the resin composition layer facing the electronic device, thereby sealing the electronic device with the second film or the glass plate and the resin composition layer. The lamination method may be a batch method or a continuous method using a roll.

[0124] The resin composition layer is usually cured by thermal curing. Examples of the means for this include a hot air circulating oven, an infrared heater, a heat gun, a high-frequency induction heating device, and heating by pressure bonding with a heat tool. From the viewpoint of bonding the cured resin composition layer (encapsulating layer) to the electronic device with a sufficiently satisfactory adhesive strength, the curing temperature is preferably 50°C or higher, more preferably 55°C or higher, and the curing time is preferably 10 minutes or longer, more preferably 20 minutes or longer. [Example]

[0125] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and can be implemented with appropriate modifications within the scope of the above and below spirit, and all such modifications are included in the technical scope of the present invention.

[0126] <Plastic film> Table 1 shows the plastic films (films A to H) used in the following examples and comparative examples, and their WVTRs measured by the method described below.

[0127] [Table 1]

[0128] * Inorganic film composed of silicon, oxygen, and carbon ** A transparent plastic layer made of polyethylene terephthalate film

[0129] In the examples and comparative examples, a film in which Film F having a barrier layer and Film C or Film D having a release layer were bonded together with an adhesive was used, and the results are described below. "C+F": A film made by bonding the opposite side of the release layer of Film C to the opposite side of the barrier layer of Film F with an adhesive (film thickness: 52 μm, total light transmittance: 89.6%) "D+F": A film made by bonding the opposite side of the release layer of Film D to the opposite side of the barrier layer of Film F with an adhesive (film thickness: 39 μm, total light transmittance: 89.6%)

[0130] Measurement of release layer peel strength: Nitto Denko polyester adhesive tape No. 31B was attached to the release layer surface, pressed with a rubber roller, and left at room temperature for 20 hours. After that, the T-type peel strength (release layer peel strength [mN / 25 mm]) was measured at a peel speed of 300 mm / min.

[0131] Measurement of total light transmittance: The total light transmittance (%) of the plastic films listed in Table 1 was measured in accordance with JIS K7361-1 using an HZ-V3 manufactured by Suga Test Instruments Co., Ltd. The measurement was performed using a D65 light source and air as a reference.

[0132] <Production of Resin Composition Varnish> (Production Example 1: Polyolefin Resin Composition Varnish A) A mixture was obtained by dispersing 130 parts by mass of a 60 mass% Swazol solution of a cyclohexane ring-containing saturated hydrocarbon resin ("Arcon P125" manufactured by Arakawa Chemical Industries, Ltd.), 35 parts by mass of maleic anhydride-modified liquid polyisobutylene ("HV-300M" manufactured by Toho Chemical Industry Co., Ltd.), 60 parts by mass of polybutene ("HV-1900" manufactured by ENEOS Corporation (formerly known as "JXTG Energy")), and 100 parts by mass of semi-calcined hydrotalcite ("DHT-4C" manufactured by Kyowa Chemical Industry Co., Ltd.) using a three-roll mill. To the resulting mixture, 200 parts by mass of a 20% by mass Swazol solution of glycidyl methacrylate-modified polypropylene-polybutene copolymer ("T-YP341" manufactured by Seiko PMC Corporation), 0.5 parts by mass of an anionic polymerization curing agent (2,4,6-tris(dimethylaminomethyl)phenol), and 16 parts by mass of toluene were blended, and the resulting mixture was uniformly dispersed in a high-speed rotating mixer to obtain polyolefin resin composition varnish A.

[0133] (Production Example 2: Polyolefin Resin Composition Varnish B) A polyolefin resin composition varnish was prepared in the same manner as polyolefin resin composition varnish A, except that the semi-calcined hydrotalcite was changed to calcium oxide ("HAL-G" manufactured by Yoshizawa Lime Industry Co., Ltd.).

[0134] (Production Example 3: Epoxy Resin Composition Varnish C) 56 parts by mass of liquid bisphenol A type epoxy resin ("jER828EL" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 185), 1.2 parts by mass of a silane coupling agent ("KBM403" manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by mass of talc powder ("FG15" manufactured by Nippon Talc Co., Ltd.), and 15 parts by mass of semi-calcined hydrotalcite ("DHT-4A-2" manufactured by Kyowa Chemical Industry Co., Ltd.) were kneaded and then dispersed using a three-roll mill to obtain a mixture. A mixture of 1.5 parts by mass of a curing accelerator ("U-3512T" manufactured by San-Apro Co., Ltd.) dissolved in 81 parts by mass of a 35% by mass solution of phenoxy resin ("YL7213" manufactured by Mitsubishi Chemical Corporation) in methyl ethyl ketone (MEK) was dispersed using the three-roll mill. This mixture was then mixed with the previously prepared mixture, 30 parts by mass of an 80% by mass MEK solution of solid bisphenol A epoxy resin ("jER1001" manufactured by Mitsubishi Chemical Corporation), 20 parts by mass of organic solvent-dispersed colloidal silica (amorphous silica particle size 10-15 nm, non-volatile content: 30% by mass, solvent: MEK, "MEK-EC-2130Y" manufactured by Nissan Chemical Industries, Ltd.), and 3 parts by mass of an ionic liquid curing agent (N-acetylglycine tetrabutylphosphonium salt), and the mixture was uniformly dispersed using a high-speed rotating mixer to obtain epoxy resin composition varnish C.

[0135] <Manufacturing of resin sheets> Example 1 Film A was used as the first film, and Film H was used as the second film. The polyolefin resin composition varnish A obtained in Production Example 1 was uniformly applied to the release layer surface of the first film using a die coater, and heated at 130°C for 60 minutes to obtain a film having a resin composition layer with a thickness of 20 µm (amount of residual solvent in the resin composition layer: approximately 1% by mass). Next, the resin composition layer of the obtained film and the barrier layer of the second film were laminated together so that they were in contact with each other, and the film was wound up into a roll. The rolled resin sheet was slit to a width of 450 mm to obtain a resin sheet measuring 450 x 300 mm.

[0136] Examples 2 to 4 and Comparative Examples 1 to 4 Resin sheets of Examples 2 to 4 and Comparative Examples 1 to 4 were produced in essentially the same manner as in Example 1, except that the films shown in Table 2 below were used as the first or second film, and the resin composition layer was formed using polyolefin resin composition varnishes A and B or epoxy resin composition varnish C obtained in Production Examples 1 to 3 (thickness of resin composition layer: 20 μm). The structures of the resulting resin sheets are shown in Table 2 below. In Example 3, in which epoxy resin composition varnish C was used, the resin composition layer was formed by applying the epoxy resin composition varnish C and then drying it at 80 to 100°C (average 90°C) for 5 minutes (amount of residual solvent in the resin composition layer: approximately 2% by mass).

[0137] Examples 5 to 6 and Comparative Examples 5 to 8 Resin sheet precursors of Examples 5 to 6 and Comparative Examples 5 to 8 were produced in essentially the same manner as in Example 1, except that the films shown in Table 3 below were used as the first film or third film and the resin composition layer was formed using the polyolefin resin composition varnish A obtained in Production Example 1 (resin composition layer thickness: 20 μm). The configurations of the obtained resin sheet precursors are shown in Table 3 below.

[0138] <Measurement method> (1) Measurement of water vapor transmission rate (WVTR) The water vapor permeability (g / m) of the plastic films listed in Table 1 2 / 24hr) was measured in accordance with JIS K7129B using a PERMATRAN-W3 / 34G manufactured by MOCON Co., Ltd. The measurement environment was 40°C and 90% RH.

[0139] (2) Measurement of moisture content The water content of the resin composition layer of the resin sheets produced in Examples 1 to 4 and Comparative Examples 1 to 4, and the resin sheet precursors produced in Examples 5 and 6 and Comparative Examples 5 to 8, before and after storage was measured as follows. The unit of water content described below is "ppm" based on mass.

[0140] First, the prepared resin sheets and resin sheet precursors were cut into 7 cm squares, and only the first film was peeled off from the resin sheets of Examples 1 to 4 and Comparative Examples 1 to 4, and the first and third films were peeled off from the resin sheet precursors of Examples 5 to 6 and Comparative Examples 5 to 8. These were used as samples before storage, and the moisture content of the resin composition layer was measured using a Karl Fischer moisture analyzer ("CA-200 Trace Moisture Analyzer" manufactured by Mitsubishi Chemical Analytech Co., Ltd.) using the coulometric titration method. The moisture content before storage (initial moisture content I) is shown in Tables 2 and 3 below.

[0141] The apparatus consists of a glass container in which a heatable sample is placed and a titration device containing a reaction solution in which the water vaporized when the sample is heated is titrated. The vaporized water moves from the glass container to the reaction solution side of the titration device by flowing nitrogen at a flow rate of 250 ± 25 ml / min. The measurement was performed by placing the sample in a glass container purged with a nitrogen atmosphere (water vapor content < 0.1 ppm (by mass)), titrating the amount of vaporized water at 130 °C, and calculating the water content of the resin composition layer.

[0142] In addition, the resin sheet and resin sheet precursor cut into 7 cm squares were stored for 7 days under an atmosphere of 25°C and 50% RH, and then the first film alone or the first and third films were peeled off in the same manner as above, and these were used as samples after storage to measure the moisture content of the resin composition layer in the same manner. The moisture content after storage (moisture content after storage II) is shown in Tables 2 and 3 below.

[0143] The ratio of the moisture content measured after storage to the moisture content before storage (i.e., moisture content after storage / moisture content before storage, hereinafter sometimes referred to as "moisture content increase rate II / I") was calculated. This ratio is also shown in Tables 2 and 3 below.

[0144] The resin sheets and resin sheet precursors were evaluated based on the ratio of the moisture content after storage to the moisture content before storage (moisture content increase rate II / I) according to the following criteria. The results are also shown in Tables 2 and 3 below. (Evaluation criteria for moisture content increase rate) ○ (Good): Moisture content increase rate is less than 2.5 × (bad): Moisture content increase rate is 2.5 or more

[0145] (Laminating a barrier film to a resin sheet precursor) The third film of the resin sheet precursor produced in Examples 5 and 6 was peeled off, and the barrier layer of Film H was laminated to the resin composition layer by vacuuming at 80°C for 30 seconds using a vacuum laminator (V-160 manufactured by Nikko Materials Co., Ltd.) and then pressing at 80°C and 0.3 MPa for 30 seconds, thereby producing a resin sheet laminated with a barrier film. The produced resin sheet was cut into 7 cm square samples, and the moisture content increase rate was measured. All of the samples were less than 1.5 (evaluated as ○ (good)), confirming the effectiveness of this configuration (that the resin sheet of the present invention can be produced using the resin sheet precursor).

[0146] (3) Optical automatic appearance inspection The first film used in the examples and comparative examples was observed with an optical automated appearance inspection (AOI) device when the resin composition varnish was applied. Specifically, an 80 m length of the first film with a width of 950 mm was subjected to the AOI, and the number of defects measuring 50 × 50 μm or more in length and width was detected and evaluated according to the following criteria. (Evaluation criteria for number of AOI detected defects) Good: The number of defects measuring 50 x 50 μm or more in length and width is less than 10. × (bad): The number of defects measuring 50 × 50 μm or more in length and width is 10 or more As a result of AOI detection, many defects were detected in the laminated film "C+F" due to voids and particles that occurred when the film was laminated with adhesive. On the other hand, Film E could not be evaluated by AOI because the aluminum foil was reflective, so it was rated as x.

[0147] (4) Warpage evaluation The prepared resin sheet and resin sheet precursor were cut into a size of 50 mm x 50 mm, and heated at 150°C for 5 minutes, and the warpage was evaluated according to the following criteria. (Warpage evaluation criteria) Good: Maximum warpage of resin sheet and resin sheet precursor is less than 1.5 cm × (Fail): Maximum warpage of resin sheet and resin sheet precursor is 1.5 cm or more

[0148] [Table 2]

[0149] [Table 3]

[0150] From the results in Tables 2 and 3, it can be seen that the resin sheets and resin sheet precursors of the examples of the present invention had good evaluations of the moisture content increase rate, and therefore can suppress water absorption in the resin composition layer during storage, etc., and also had good detection accuracy for the number of AOI-detected defects in the resin composition layer, and good evaluations of warpage, thereby enabling stable mass production. [Industrial Applicability]

[0151] The resin sheet and resin sheet precursor of the present invention can suppress water absorption in the resin composition layer during storage, etc. (particularly, water absorption in the resin composition layer containing semi-calcined hydrotalcite or calcium oxide), making it possible to inspect the resin composition layer of the resin sheet for foreign matter with high accuracy using an optical automated inspection device (AOI), and can suppress warping when forming the resin composition layer.

[0152] This application is based on patent application No. 2022-050185 filed in Japan, the contents of which are incorporated in their entirety herein.

Claims

[Claim 1] A resin sheet having a first film, a resin composition layer, and a second film or a glass plate, a resin composition layer is present between the first film and the second film or between the first film and the glass plate; the first film has a single-layer plastic film as a substrate, a barrier layer formed on a surface of the plastic film, and a release layer formed on a surface of the barrier layer that is not in contact with the plastic film or on a surface of the plastic film that does not have the barrier layer; the first film is a transparent film, The water vapor permeability of the first film is 0.01 (g / m ２ / 24hr) or more 1 (g / m ２ / 24 hr) or less, the release layer of the first film is in contact with the resin composition layer, The second film does not have a release layer, The water vapor permeability of the second film is 0.01 (g / m ２ / 24 hr) or less, The glass plate does not have a release layer; Resin sheet.

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