TWI843699B - Sealing sheet - Google Patents

Abstract

The present invention provides a sealing sheet having a first film, a resin composition layer and a second film, wherein the resin composition layer exists between the first film and the second film, and the water vapor permeability of the first film and the second film is respectively less than 1 (g/m ² /24hr).

Description

Sealing sheet

The present invention relates to a sealing sheet suitable for sealing an organic EL element, etc.

Organic EL (Electroluminescence) elements are luminescent elements that use organic substances as luminescent materials, and have become the focus of attention in recent years. However, organic EL elements are extremely weak to moisture, and there are problems such as the brightness being reduced by moisture. In order to protect organic EL elements from moisture, a sealing sheet having a resin composition layer is used to seal the organic EL elements.

The sealing sheet is generally composed of a support, a resin composition layer, and a cover film for protecting the resin composition layer (for example, Patent Document 1).

In addition, as a method for improving the moisture blocking property of a sealing sheet, it is known to mix semi-sintered hydrotalcite in the resin composition layer of the sealing sheet (for example, Patent Document 2). [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2016-186843 [Patent Document 2] International Publication No. 2017/135112

[The problem that the invention wants to solve]

Paragraphs [0015] and [0016] of Patent Document 1 state that a plastic film such as polyethylene terephthalate or a plastic film having a barrier layer is used as a support. However, paragraph [0018] of the same patent document states only that "the covering film used as a sealing sheet may be a plastic film that is the same as the support", but does not state that a plastic film having a barrier layer is used as the covering film.

If a plastic film with high moisture permeability without a barrier layer is used as a cover film for a sealing sheet, there is a possibility that moisture that passes through the cover film will mix into the resin composition layer during storage of the sealing sheet. As a result, the performance of the sealing sheet in protecting the organic EL element from moisture is reduced. If such a sealing sheet is used to seal an organic EL element, there is a possibility that the life of the organic EL device will be shortened.

In addition, the sealing sheet having a resin composition layer containing semi-sintered hydrotalcite can achieve high water shielding properties by semi-sintered hydrotalcite, but semi-sintered hydrotalcite has the property of reversibly absorbing and releasing water. Therefore, in the sealing sheet having a resin composition layer containing semi-sintered hydrotalcite, for example, during the storage of the sealing sheet, the semi-sintered hydrotalcite absorbs water and then releases the absorbed water into the resin composition layer. If an organic EL element is sealed with a resin composition layer containing water released in this way, there is a concern that the life of the organic EL device will be shortened.

The present invention is made in view of the above-mentioned matters, and its object is to provide a sealing sheet that can suppress water absorption of a resin composition layer (particularly, water absorption of a resin composition layer containing semi-sintered hydrotalcite) during storage. [Means for Solving the Problem]

As a result of repeated and intensive studies to achieve the above object, the inventors have found that by using two films (hereinafter referred to as "moisture-proof films") having a water vapor transmission rate (hereinafter referred to as "WVTR") of 1 (g/ ^m2 /24hr) or less as measured by the method described in the examples below, and placing a resin composition layer therebetween, water absorption of the resin composition layer (particularly, water absorption of the resin composition layer containing semi-sintered hydrotalcite) can be suppressed. The present invention based on this knowledge is as follows.

[1] A sealing sheet comprising a first film, a resin composition layer and a second film, wherein the resin composition layer is present between the first film and the second film, and the water vapor permeability of the first film and the second film is each less than 1 (g/m ² /24hr).

[2] The sealing sheet as described in [1] above, wherein the water vapor permeability of the first film and the second film is respectively 0.01 (g/m ² /24hr) or more and 1 (g/m ² /24hr) or less. [3] The sealing sheet as described in [1] above, wherein the water vapor permeability of the first film and the second film is respectively 0.01 (g/m ² /24hr) or more and 0.5 (g/m ² /24hr) or less. [4] The sealing sheet as described in [1] above, wherein the water vapor permeability of the first film and the second film is respectively 0.01 (g/m ² /24hr) or more and 0.2 (g/m ² /24hr) or less. [5] The sealing sheet according to [1] above, wherein the water vapor permeability of the first film and the second film is respectively 0.05 (g/m ² /24hr) or more and 0.2 (g/m ² /24hr) or less.

[6] The sealing sheet as described in [1] above, wherein the water vapor permeability of the first film is less than 0.01 (g/m ² /24hr), and the water vapor permeability of the second film is greater than 0.01 (g/m ² /24hr) and less than 1 (g/m ² /24hr).

[7] The sealing sheet as described in [6] above, wherein the water vapor permeability of the first film is 0.005 (g/m ² /24hr) or less. [8] The sealing sheet as described in [6] above, wherein the water vapor permeability of the first film is 0.001 (g/m ² /24hr) or less. [9] The sealing sheet as described in [6] above, wherein the water vapor permeability of the first film is 0.0005 (g/m ² /24hr) or less.

[10] The sealing sheet as described in any one of [6] to [9] above, wherein the water vapor permeability of the second film is 0.01 (g/m ² /24hr) or more and 0.5 (g/m ² /24hr) or less. [11] The sealing sheet as described in any one of [6] to [9] above, wherein the water vapor permeability of the second film is 0.01 (g/m ² /24hr) or more and 0.2 (g/m ² /24hr) or less. [12] The sealing sheet as described in any one of [6] to [9] above, wherein the water vapor permeability of the second film is 0.05 (g/m ² /24hr) or more and 0.2 (g/m ² /24hr) or less.

[13] The sealing sheet as described in [1] above, wherein the water vapor permeability of the first film is less than 0.0005 (g/m ² /24hr), and the water vapor permeability of the second film is more than 0.0005 (g/m ² /24hr) and less than 0.01 (g/m ² /24hr).

[14] A sealing sheet as described in any one of [1] to [13] above, wherein the first film and the second film are films having a substrate and a barrier layer. [15] A sealing sheet as described in [14] above, wherein the substrate is a plastic film. [16] A sealing sheet as described in [14] or [15] above, wherein the barrier layer comprises an inorganic film.

[17] A sealing sheet as described in any one of [1] to [16] above, wherein the resin composition layer comprises an olefinic resin and/or an epoxy resin. [18] A sealing sheet as described in any one of [1] to [17] above, wherein the resin composition layer comprises semi-sintered hydrotalcite.

[19] A sealing sheet as described in any one of [1] to [18] above, wherein the first film is a film having a release layer. [20] A sealing sheet as described in any one of [1] to [19] above, wherein the first film and the second film are films having a release layer.

[21] The sealing sheet as described in any one of [1] to [20] above, which is used for sealing an organic EL element. [Effects of the Invention]

According to the present invention, it is possible to suppress water absorption of a resin composition layer of a sealing sheet (particularly water absorption of a resin composition layer containing semi-sintered hydrotalcite).

The sealing sheet of the present invention comprises a first film, a resin composition layer and a second film, and both the first film and the second film are moisture-proof films. The moisture-proof film may also be a laminated film. The first film and the second film may be the same or different. Furthermore, the WVTR values of the first film and the second film may be the same or different. In JIS, a film having a thickness of less than 0.25 mm is classified as a film, and a film having a thickness of more than 0.25 mm is classified as a sheet, but the present invention is not limited by such classification.

The WVTR of the moisture-proof film is preferably 0.01 (g/m ² /24hr) or more and 1 (g/m ² /24hr) or less, more preferably 0.5 (g/m ² /24hr) or less, and more preferably 0.2 (g/m ² /24hr) or less. This WVTR is a value measured by the method described in the Examples below.

The WVTR of the moisture-proof film used as the first film and the second film can be appropriately set to an ideal state by the structure of the organic EL device to which the sealing sheet of the present invention is applied.

When a layer having high moisture barrier properties is provided in the structure of an organic EL device, it is preferable to use a moisture barrier film having a WVTR of less than 0.01 (g/m ² /24hr) (hereinafter referred to as "high moisture barrier film") as the first film (support) of the present invention. The WVTR of the high moisture barrier film is preferably 0.005 (g/m ² /24hr) or less, more preferably 0.001 (g/m ² /24hr) or less, and particularly preferably 0.0005 (g/m ² /24hr) or less. There is no particular lower limit on the WVTR of the high moisture barrier film, but a lower value is preferable, and 0 (g/m ² /24hr) is most preferable. In this case, the second film (cover film) is peeled off and discarded during sealing. Therefore, from the viewpoint of simultaneously suppressing the water absorption of the resin composition layer during storage and suppressing the cost, it is desirable to use a moisture-proof film (hereinafter referred to as "medium moisture-proof film") having a WVTR of 0.01 (g/m ² /24hr) or more and 1 (g/m ² /24hr) or less as the second film. In this case, the WVTR of the medium moisture-proof film is preferably 0.05 (g/m ² /24hr) or more, more preferably 0.5 (g/m 2 /24hr) or less, and more preferably 0.2 (g/m ² /24hr) or less, from the viewpoint of balancing moisture- ^proofness and cost.

Furthermore, for example, when the WVTR of the first film is 0.0005 (g/m ² /24hr) or less, which is an extremely high moisture barrier, a moisture barrier film having a WVTR of more than 0.0005 (g/m ² /24hr) and less than 0.01 (g/m ² /24hr) may be used as the second film. A moisture barrier film having a WVTR of 0.0005 (g/m ² /24hr) or less is generally manufactured by forming multiple layers of inorganic films on a plastic film by evaporation, etc., which is expensive. On the other hand, as a moisture-proof film having a WVTR of more than 0.0005 (g/m ² /24hr) and less than 0.01 (g/m ² /24hr), for example, a plastic film with a metal foil that can be manufactured at a relatively low cost can be used. Therefore, by setting the first film and the second film to the above-mentioned structure, a sealing film that strikes a balance between suppressing water absorption of the resin composition layer during storage and cost can be set. In terms of relatively low cost, it is best to use the moisture-proof film mentioned above as the second film.

In addition, if an opaque moisture-proof film such as a film with metal foil is used as both the first film and the second film, it becomes difficult to inspect the quality of the resin composition layer. Therefore, when an opaque moisture-proof film is used as one of the first film and the second film, it is best to use a transparent moisture-proof film as the other. The transparency of a transparent moisture-proof film is not determined by the thickness, and the best is when the total light transmittance of D65 light is 85% or more. The so-called "opaque moisture-proof film" is defined as "a moisture-proof film with a total light transmittance of D65 light of less than 50%." The total light transmittance can be measured with D65 light using Haze meter-HZ-V3 (halogen lamp) manufactured by Suga Testing Instrument Co., Ltd., with air as the reference.

In the structure of an organic EL device, when an inorganic film is directly provided on a sealing layer formed of a resin composition layer, or when a high moisture resistant layer is not required or provided, it is ideal to use the above-mentioned moisture-proof film as both the first film and the second film.

Furthermore, when a low moisture-proof film having a WVTR exceeding 1 (g/m ² /24 hr) is used as either or both of the first film and the second film, it becomes difficult to obtain the effect of the present invention.

The moisture-proof film is preferably a film having a substrate and a barrier layer. Here, the substrate means the portion other than the barrier layer in the aforementioned film.

The substrate may be a single-layer film or a laminated film. Examples of the substrate include polyolefins such as polyethylene and polypropylene (PP), polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), cycloolefin polymer (COP), polyvinyl chloride, and other plastic films. The plastic film may be only 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 (when the substrate is a laminated film, it is the thickness of the entire film) is preferably 10 to 100 μm, more preferably 12.5 to 75 μm, and even more preferably 12.5 to 50 μm.

As the barrier layer, for example, inorganic films such as metal foil (e.g., aluminum foil), silicon dioxide evaporated film, silicon nitride film, silicon oxide film, etc. can be cited. The barrier layer can also be composed of multiple layers of multiple inorganic films (e.g., metal foil and silicon dioxide evaporated film). In addition, the barrier layer can be composed of organic and inorganic substances, and can also be a composite multilayer of organic layers and inorganic films. The thickness of the barrier layer is preferably 0.01 to 100 μm, more preferably 0.05 to 50 μm, and more preferably 0.05 to 30 μm.

The moisture-proof film (high moisture-proof film) having a WVTR of less than 0.01 (g/m ² /24hr), particularly the moisture-proof film having a WVTR of less than 0.0005 (g/m ² /24hr) is, for example, an inorganic film of silicon oxide (silicon dioxide), aluminum oxide, magnesium oxide, silicon nitride, silicon oxynitride, SiCN, amorphous silicon, etc., can be deposited on the surface of a substrate by chemical vapor deposition (e.g., chemical vapor deposition by heat, plasma, ultraviolet, vacuum heat, vacuum plasma or vacuum ultraviolet), or by physical vapor deposition. The inorganic film is manufactured by a phase deposition method (e.g., vacuum evaporation, sputtering, ion plating, laser deposition, molecular beam epitaxy) in a single layer or multiple layers (e.g., see Japanese Patent Publication No. 2016-185705, Japanese Patent No. 5719106, Japanese Patent No. 5712509, Japanese Patent No. 5292358, etc.). In order to prevent cracking of the inorganic film, it is ideal to alternately laminate the inorganic film and the transparent planarization layer (e.g., a transparent plastic layer). The moisture-proof film manufactured by such a method is a transparent film.

In addition, among moisture-proof films (high moisture-proof films) having a WVTR of less than 0.01 (g/m ² /24hr), high moisture-proof films having a WVTR of more than 0.0005 (g/m ² /24hr) and less than 0.01 (g/m ² /24hr) include, in addition to moisture-proof films produced by the above-mentioned methods, metal foils such as SUS foil and aluminum foil, or moisture-proof films produced by bonding a substrate and a metal foil via an adhesive. Metal foils or moisture-proof films composed of a substrate and a metal foil are generally opaque.

The moisture-proof film (medium moisture-proof film) with a WVTR of 0.01 (g/m ² /24hr) or more and 1 (g/m ² /24hr) or less can be produced, for example, as a barrier layer, by evaporating an inorganic film containing inorganic materials such as silicon oxide (silicon dioxide), aluminum oxide, magnesium oxide, silicon nitride, silicon oxynitride, SiCN, amorphous silicon, etc. on the surface of a substrate, or by applying a coating liquid composed of a metal oxide and an organic resin having barrier properties on the substrate and drying the coating liquid (for example, refer to Japanese Patent Publication No. 2013-108103, Japanese Patent Publication No. 4028353, etc.). The moisture-proof film produced by such a method is a transparent film.

Commercially available products are also used as moisture-proof films. Examples of commercially available products of medium moisture-resistant films include "KURARISTER CI" manufactured by Kuraray, "TECHBARRIER HX", "TECHBARRIER LX" and "TECHBARRIER L" manufactured by Mitsubishi Resin, "IB-PET-PXB" manufactured by Dai Nippon Printing, and "GL, GX Series" manufactured by Toppan Printing. Examples of commercially available products of high moisture-resistant films include "PET luck AL1N30" manufactured by Toyo Aluminum, and "X-BARRIER" manufactured by Mitsubishi Resin.

The moisture-proof film may also have layers other than the substrate and the barrier layer. For example, in order to prevent cracking of the inorganic film, it is ideal to alternately laminate the inorganic film and the transparent planarization layer (for example, a transparent plastic layer). In addition, it may also have a laminated structure in which a plastic film is adhered to the barrier layer and/or the substrate surface using an adhesive. In the present invention, there is no particular limitation on the adhesive, and commercially available adhesives can be used. In addition, as plastics, for example, polyolefins such as polyethylene and polypropylene (PP), polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), cycloolefin polymer (COP), polyvinyl chloride, etc. can be cited. The plastic film may be only one type or may be two or more types.

In the sealing sheet of the present invention, the resin composition layer exists between the first film and the second film. Other layers may be included between the first film and the resin composition layer and/or between the second film and the resin composition layer as long as the effect of the present invention is not hindered. The second film serving as a covering film is peeled off before laminating the sealing film on the organic EL element in order to expose the resin composition layer. The first film serving as a support is used as it is without being peeled off when it is installed in the device as a moisture-proof layer, and is peeled off at any step after lamination when it is not installed. The second film serving as the covering film may have a release layer on the surface in contact with the resin composition layer in order to facilitate peeling. Furthermore, when the first film serving as the support is not mounted on the device but is peeled off in a step after lamination, for example, the surface in contact with the resin composition layer may have a release layer. When the first film is mounted on the device and is not peeled off, the first film usually does not have a release layer. Furthermore, when a moisture-proof layer is provided in the organic EL device, the first film may be used as the moisture-proof layer as it is, or a moisture-proof layer may be provided separately after the first film is peeled off. When a moisture-proof layer, a circular polarizing plate, a color filter, or a touch panel is provided on an organic EL device, the circular polarizing plate, the color filter, or the touch panel may be provided on the surface opposite to the resin component layer. A circular polarizing plate is generally composed of a polarizing plate and a 1/4 wavelength plate, and the 1/4 wavelength plate of the circular polarizing plate is disposed on the resin component layer.

The release layer can be formed, for example, by applying a release agent to a moisture-proof film or a laminated film including a moisture-proof film and drying the film. Alternatively, a plastic film having a release layer can be formed by applying a release agent to a plastic film and drying the film, and then an adhesive is used to bond the plastic film having a release layer to the moisture-proof film. The drying temperature after applying the release agent is, for example, 100 to 150° C., and the drying time is, for example, 5 to 120 minutes.

Examples of the release agent include silicone release agents, alkyd release agents, fluorine release agents, and olefin release agents. The release layer is preferably formed of silicone release agents or alkyd release agents. 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.

The thickness of the first film (the thickness of the entire film if the first film is a laminated film) is preferably 12.5 to 100 μm, more preferably 12.5 to 62.5 μm, and more preferably 12.5 to 55 μm. The thickness of the second film (the thickness of the entire film if the second film is a laminated film) is preferably 12.5 to 100 μm, more preferably 12.5 to 62.5 μm, and more preferably 12.5 to 55 μm.

In the present invention, the resin composition layer is not particularly limited, and a generally known resin composition can be used to form the resin composition layer. In order to seal the organic EL element well, the resin composition layer preferably contains an olefin resin and/or an epoxy resin.

The olefin resin may be only one or more than one. The olefin resin is not particularly limited as long as it has a skeleton derived from an olefin monomer. Ethylene resins, propylene resins, butylene resins, and isobutylene resins are preferred as olefin resins. These olefin resins may be homopolymers, or copolymers such as random copolymers and block copolymers. Copolymers may be copolymers of two or more olefins, and copolymers of olefins and monomers other than olefins such as non-conjugated dienes and styrene. As examples of desirable copolymers, there can be cited ethylene-non-conjugated diene copolymers, ethylene-propylene copolymers, ethylene-propylene-non-conjugated diene copolymers, ethylene-butene copolymers, propylene-butene copolymers, propylene-butene-non-conjugated diene copolymers, styrene-isobutylene copolymers, styrene-isobutylene-styrene copolymers, etc. As polyolefin resins, for example, isobutylene modified resins, styrene-isobutylene modified resins, modified propylene-butene resins, etc. can be preferably used.

From the viewpoint of imparting excellent physical properties such as adhesiveness, the olefinic resin preferably includes at least one selected from the group consisting of an olefinic resin having an acid anhydride group (i.e., a carbonyloxycarbonyl group (-CO-O-CO-)) and an olefinic resin having an epoxy group, and more preferably includes an olefinic resin having an acid anhydride group and an olefinic resin having an epoxy group.

Examples of the anhydride group include a group derived from succinic anhydride, a group derived from maleic anhydride, and a group derived from glutaric anhydride. The anhydride group may be one or more. The anhydride group-containing olefinic resin may be obtained by, for example, grafting an unsaturated compound having an anhydride group onto an olefinic resin under free radical reaction conditions. In addition, the unsaturated compound having an anhydride group may be free radically copolymerized with an olefin or the like. Similarly, an olefinic resin having an epoxy group can be obtained by grafting an unsaturated compound having an epoxy group, such as glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, and allyl glycidyl ether, onto an olefinic resin under free radical reaction conditions. In addition, an unsaturated compound having an epoxy group can also be free radically copolymerized with an olefin or the like.

The concentration of the acid anhydride group in the olefinic resin having an acid anhydride group is preferably 0.05 to 10 mmol/g, more preferably 0.1 to 5 mmol/g. The concentration of the acid anhydride group is obtained by the acid value defined as the number of mg of potassium hydroxide required to neutralize the acid present in 1 g of the resin according to JIS K 2501. The amount of the olefinic resin having an acid anhydride group in the olefinic resin is preferably 0 to 70% by mass, more preferably 10 to 50% by mass.

The concentration of epoxy groups in the olefinic resin having epoxy groups is preferably 0.05 to 10 mmol/g, more preferably 0.1 to 5 mmol/g. The epoxy group concentration is determined from the available epoxy equivalent according to JIS K 7236-1995. The amount of the olefinic resin having epoxy groups in the olefinic resin is preferably 0 to 70% by mass, more preferably 10 to 50% by mass.

From the perspective of imparting excellent physical properties such as moisture resistance, olefin resins preferably include both olefin resins having anhydride groups and olefin resins having epoxy groups. Such olefin resins can form a crosslinked structure by reacting the anhydride groups and epoxy groups by heating, forming a sealing layer (resin component layer) having excellent moisture resistance. The crosslinked structure can be formed after sealing, but in the case of an organic EL element, for example, where the sealing object is not heat-resistant, it is best to use a sealing film for sealing, and form the crosslinked structure first when the sealing film is manufactured. The ratio of the olefinic resin having anhydride groups to the olefinic resin having epoxy groups is not particularly limited as long as a suitable cross-linking structure can be formed, but the molar ratio of epoxy groups to anhydride groups (epoxy groups:anhydride groups) is preferably 100:10 to 100:200, more preferably 100:50 to 100:150, and particularly preferably 100:90 to 100:110.

The number average molecular weight of the olefinic resin is not particularly limited, but is preferably 1,000,000 or less, more preferably 750,000 or less, more preferably 500,000 or less, 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 from the viewpoint of providing good coating properties of the resin composition varnish and good compatibility with other components in the resin composition. On the other hand, from the viewpoint of preventing shrinkage cracking during application of the resin composition varnish, making the moisture-proof property of the formed resin composition layer manifest, and improving the mechanical strength, the number average molecular weight is preferably 1,000 or more, more preferably 3,000 or more, more preferably 5,000 or more, more preferably 10,000 or more, more preferably 30,000 or more, and particularly preferably 50,000 or more. In addition, the number average molecular weight in the present invention is measured by gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the number average molecular weight determined by the GPC method uses LC-9A/RID-6A manufactured by Shimadzu Corporation as a measuring apparatus, Shodex K-800P/K-804L/K-804L manufactured by Showa Denko K.K. as a column, toluene or the like as a mobile phase, and is measured at a column temperature of 40°C. The molecular weight can be calculated using a calibration curve of standard polystyrene.

From the viewpoint of suppressing the decrease in fluidity due to the increase in viscosity of the varnish, an amorphous olefinic resin is preferable. Here, the amorphous olefinic resin means that the olefinic resin does not have a clear melting point. For example, an olefinic resin can be used in which no clear peak is observed when the melting point is measured by DSC (differential scanning calorimetry).

The amount of the olefinic resin is not particularly limited. From the viewpoint of good coating properties, when the olefinic resin is used, the amount is preferably 80% by mass or less, more preferably 75% by mass or less, more preferably 70% by mass or less, more preferably 60% by mass or less, more preferably 55% by mass or less, and particularly preferably 50% by mass or less, based on the total amount of the resin composition layer (i.e., the total amount of non-volatile components of the resin composition). On the other hand, from the viewpoint of improving moisture resistance and transparency, the amount of the olefinic resin is preferably 1 mass % or more per the total amount of the resin composition layer (that is, the total amount of non-volatile components per resin composition), more preferably 3 mass % or more, more preferably 5 mass % or more, more preferably 7 mass % or more, even more preferably 10 mass % or more, particularly preferably 35 mass % or more, and most preferably 40 mass % or more.

Next, specific examples of olefin resins are described. Specific examples of isobutylene resins include "Oppanol B100" (viscosity average molecular weight: 1,110,000) manufactured by BASF and "B50SF" (viscosity average molecular weight: 400,000) manufactured by BASF.

Specific examples of butene resins include "HV-1900" manufactured by JX Energy Co., Ltd. (polybutene, number average molecular weight: 2,900), and "HV-300M" manufactured by Toho Chemical Industries, Ltd. (maleic anhydride-modified liquid polybutene ("HV-300" (number average molecular weight: 1,400) modified product), number average molecular weight 2,100, number of carboxyl groups constituting anhydride groups: 3.2/1 molecule, acid value: 43.4 mg KOH/g, anhydride group concentration: 0.77 mmol/g).

A specific example of styrene-isobutylene copolymer is "SIBSTAR T102" (styrene-isobutylene-styrene block copolymer, number average molecular weight: 100,000, styrene content: 30% by mass), "T-YP757B" (maleic anhydride modified styrene-isobutylene-styrene block copolymer, anhydride group concentration: 0.464mmol/g, number average molecular weight: 100,000) manufactured by Starlight PMC, "T-YP766" (methacrylate glycidyl modified styrene-isobutylene-styrene block copolymer, epoxy group concentration: 0.638mmol/g, number average molecular weight: 100,000) manufactured by Starlight PMC, "T-YP8920" (maleic anhydride modified styrene-isobutylene-styrene copolymer, anhydride group concentration: 0.464 mmol/g, number average molecular weight: 35,800), Starlight PMC's "T-YP8930" (methacrylate-modified styrene-isobutylene-styrene copolymer, epoxy concentration: 0.638mmol/g, number average molecular weight: 48,700).

Specific examples of the ethylene resin or propylene resin include "EPT X-3012P" manufactured by Mitsui Chemicals (ethylene-propylene-5-ethylidene-2-norbornene copolymer), "EPT 1070" manufactured by Mitsui Chemicals (ethylene-propylene-dicyclopentadiene copolymer), and "TAFMER A 4085" manufactured by Mitsui Chemicals (ethylene-butene copolymer).

Specific examples of ethylene-methyl methacrylate copolymers include "T-YP429" manufactured by Starlight PMC (a 20% by mass toluene solution of maleic anhydride-modified ethylene-methyl methacrylate copolymer (the amount of methyl methacrylate units per 100% by mass of the total of ethylene units and methyl methacrylate units: 32% by mass, anhydride group concentration: 0.46 mmol/g, number average molecular weight: 2,300)), "T-YP430" manufactured by Starlight PMC (a maleic anhydride-modified ethylene-methyl methacrylate copolymer, the amount of methyl methacrylate units per 100% by mass of the total of ethylene units and methyl methacrylate units: 32% by mass, anhydride group concentration: 1.18 mmol/g, number average molecular weight: 4,500), and "T-YP "T-YP 431" (20 mass% toluene solution of ethylene-methyl methacrylate copolymer modified with glycidyl methacrylate (epoxy group concentration: 0.64 mmol/g, number average molecular weight: 2,400)) manufactured by Starlight PMC Co., Ltd. (20 mass% toluene solution of ethylene-methyl methacrylate copolymer modified with glycidyl methacrylate (epoxy group concentration: 0.64 mmol/g, number average molecular weight: 2,400)), "T-YP 432" (ethylene-methyl methacrylate copolymer modified with glycidyl methacrylate, epoxy group concentration: 1.63 mmol/g, number average molecular weight: 3,100) manufactured by Starlight PMC Co., Ltd.

As a specific example of propylene-butene copolymer, there is "T-YP341" manufactured by Starlight PMC (methacrylate glycidyl modified propylene-butene random copolymer (amount of butene units per 100% by mass of the total of propylene units and butene units: 29% by mass, epoxy group concentration: 0.638% by mass). mmol/g), number average molecular weight: 155,000), "T-YP279" manufactured by Starlight PMC (maleic anhydride modified propylene-butene random copolymer, the amount of butene units per 100% by mass of propylene units and butene units: 36% by mass, anhydride group concentration: 0.464mmol/g, number average molecular weight: 35,000), "T-YP276" manufactured by Starlight PMC (glycidyl methacrylate modified propylene-butene random copolymer, the amount of butene units per 100% by mass of propylene units and butene units: 36% by mass, epoxy group concentration: 0.638mmol/g), number average molecular weight "T-YP312" manufactured by Starlight PMC (a 40% toluene solution of a propylene-butene random copolymer modified with maleic anhydride (amount of butene units per 100% by mass of the total of propylene units and butene units: 29% by mass, anhydride group concentration: 0.464 mmol/g, number average molecular weight: 60,900), "T-YP313" manufactured by Starlight PMC (a 20% toluene solution of a propylene-butene random copolymer modified with glycidyl methacrylate (amount of butene units per 100% by mass of the total of propylene units and butene units: 29% by mass, epoxy group concentration: 0.638 mmol/g, number average molecular weight: 155,000)).

When the olefinic resin includes an olefinic resin having an epoxy group, an olefinic resin that can react with an epoxy group and has a functional group other than an acid anhydride group may also be used. Examples of the functional group include a hydroxyl group, a phenolic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride group.

When the olefinic resin includes an olefinic resin having an acid anhydride group, an olefinic resin that can react with an acid anhydride group and has a functional group other than an epoxide group may also be used. Examples of the functional group include a hydroxyl group, a primary or secondary amine group, a thiol group, an epoxide group, and an oxacyclobutane group.

Epoxy resins may be used without limitation as long as they have 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., tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyl toluidine, diglycidyl glyceryl aniline), alicyclic epoxy resins, aliphatic chain 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 bisphenol, diglycidyl ethers of naphthalene diol, diglycidyl ethers of phenols, diglycidyl ethers of alcohols, and alkyl substituted products, halides and hydrogenated products of these epoxy resins. The epoxy resin may be only one type or two or more types.

The epoxy equivalent of the epoxy resin is preferably 50 to 5,000, more preferably 50 to 3,000, more preferably 80 to 2,000, more preferably 100 to 1,000, more preferably 120 to 1,000, and more preferably 140 to 300, from the viewpoint of reactivity. Here, the so-called "epoxy equivalent" is the number of grams of the resin containing 1 gram equivalent of epoxy groups (g/eq), and is measured according to the method specified in JIS K 7236. In addition, the weight average molecular weight of the epoxy resin is preferably 5,000 or less.

Epoxy resin can be either liquid or solid, and both liquid epoxy resin and solid epoxy resin can be used. Here, the so-called "liquid" and "solid" refer to the state of epoxy resin at room temperature (25°C) and normal pressure (1 atmosphere).

The amount of epoxy resin is not particularly limited. When epoxy resin is used, the amount is the total amount per resin component layer (i.e., the total amount of non-volatile components per resin component), preferably 20 to 80 mass %, more preferably 30 to 70 mass %, and even more preferably 50 to 65 mass %.

From the viewpoint of the moisture blocking property of the sealing sheet of the present invention, it is preferable that the resin composition layer contains semi-sintered hydrotalcite. The semi-sintered hydrotalcite may be only one kind or two or more kinds.

Hydrotalcite can be classified into unsintered hydrotalcite, semi-sintered hydrotalcite and sintered hydrotalcite.

Unsintered hydrotalcite is a metal hydroxide having a layered crystal structure such as represented by natural hydrotalcite (Mg ₆ Al ₂ (OH) ₁₆ CO ₃・4H ₂ O), and is composed of layers [Mg _1-X Al _X (OH) ₂ ] ^{X +} as a basic skeleton and intermediate layers [(CO ₃ ) _X/2・mH ₂ O] ^X- . Unsintered hydrotalcite in the present invention is a concept including hydrotalcite compounds such as synthetic hydrotalcite. Examples of hydrotalcite-like compounds include those represented by the following formula (I) and the following formula (II).

(In the formula, ^{M2 +} represents a divalent metal ion such as _{Mg2 +} , ^{Zn2 +} , etc., ^{M3 +} represents a trivalent metal ion such as ^{Al3 +} , ^{Fe3 +,} etc., ^An- represents an n-valent anion such as _CO32- , ^{Cl- ,} _NO3- ^, etc., 0＜x＜1, 0≦m＜1, and n is a positive number). In formula (I), ^{M2 +} is ideally ^{Mg2 +} , ^{M3 +} is ideally ^{Al3 +} , and ^An- is ideally _CO32- ^.

(In the formula, M ^{2 +} represents a divalent metal ion such as Mg ^{2 +} and Zn ^{2 +} , An- represents an ⁿ -valent anion such as CO ₃ ^2- , Cl ^- , NO ^3- , x is a positive number greater than or equal to 2, z is a positive number less than or equal to 2, m is a positive number, and n is a positive number.) In formula (II), M ^{2 +} is preferably Mg ^{2 +} , and ^An- is preferably CO ₃ ^2- .

Semi-sintered hydrotalcite is a metal hydroxide obtained by sintering unsintered hydrotalcite and having a layered crystal structure in which the amount of interlayer water is reduced or absent. The so-called "interlayer water" is explained using the composition formula and refers to the "H ₂ O" described in the composition formula of the unsintered natural hydrotalcite and hydrotalcite-like compounds mentioned above.

On the other hand, sintered hydrotalcite is obtained by sintering unsintered hydrotalcite or semi-sintered hydrotalcite, and not only interlayer water but also hydroxyl groups disappear due to condensation dehydration, and it is a metal oxide with an amorphous structure.

Unsintered hydrotalcite, semi-sintered hydrotalcite and sintered hydrotalcite can be distinguished by their saturated water absorption. The saturated water absorption of semi-sintered hydrotalcite is 1% by mass or more and less than 20% by mass. On the other hand, the saturated water absorption of unsintered hydrotalcite is less than 1% by mass, and the saturated water absorption of sintered hydrotalcite is 20% by mass or more.

The so-called "saturated water absorption rate" in the present invention refers to the mass increase rate relative to the initial mass when 1.5 g of unsintered hydrotalcite, semi-sintered hydrotalcite or sintered hydrotalcite is weighed on a scale, the initial mass is measured, and then the sample is placed in a small environmental tester (SH-222 manufactured by espec) set to 60°C and 90%RH (relative humidity) under atmospheric pressure for 200 hours. The mass increase rate can be calculated using the following formula (i): Saturated water absorption rate (mass %) = 100 × (mass after moisture absorption - initial mass) / initial mass (i).

The saturated water absorption rate of the semi-sintered 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.

In addition, unsintered hydrotalcite, semi-sintered hydrotalcite and sintered hydrotalcite can be distinguished by the thermogravimetric loss rate measured by thermogravimetric analysis. The thermogravimetric loss rate of semi-sintered hydrotalcite at 280°C is less than 15% by mass, and the thermogravimetric loss rate at 380°C is 12% by mass or more. On the other hand, the thermogravimetric loss rate of unsintered hydrotalcite at 280°C is 15% by mass or more, and the thermogravimetric loss rate of sintered hydrotalcite at 380°C is less than 12% by mass.

Thermogravimetric analysis was performed using TG/DTA EXSTAR6300 manufactured by Hitachi High-Tech Science. 5 mg of hydrotalcite was weighed on an aluminum sample plate. The plate was left uncovered and the temperature was raised from 30°C to 550°C at a rate of 10°C/min in an environment with a nitrogen flow rate of 200 mL/min. The thermogravimetric loss rate can be calculated using the following formula (ii): Thermogravimetric loss rate (mass %) = 100 × (mass before heating - mass when reaching a specific temperature) / mass before heating (ii).

In addition, unsintered hydrotalcite, semi-sintered hydrotalcite and sintered hydrotalcite can be distinguished by the peaks and relative intensity ratios measured by powder X-ray diffraction. Semi-sintered hydrotalcite shows a peak split into two at about 8 to 18° or a peak with a shoulder by the combination of two peaks in 2θ by powder X-ray diffraction, and the relative intensity ratio (low-angle side diffraction intensity/high-angle side diffraction intensity) of the diffraction intensity of the peak or shoulder appearing on the low-angle side (= low-angle side diffraction intensity) and the diffraction intensity of the peak or shoulder appearing on the high-angle side (= high-angle side diffraction intensity) is 0.001 to 1,000. On the other hand, unsintered hydrotalcite has only one peak around 8-18°, or the relative intensity ratio of the diffraction intensity between the peak or shoulder appearing at the low angle and the peak or shoulder appearing at the high angle is outside the aforementioned range. Sintered hydrotalcite has no characteristic peak in the region of 8-18°, but has a characteristic peak at 43°. Powder X-ray diffraction measurement was performed by a powder X-ray diffraction device (Empyrean, PANalytical) with cathode CuKα (1.5405Å), voltage: 45V, current: 40mA, sampling width: 0.0260˚, scanning speed: 0.0657˚/s, and measurement diffraction angle range (2θ): 5.0131-79.9711˚. Peak search was performed using the peak search function of the software attached to the diffraction device under the conditions of "minimum significance: 0.50, minimum peak search: 0.01˚, maximum peak search: 1.00˚, peak base width: 2.00˚, method: minimum value of second derivative".

The BET specific surface area of semi-sintered hydrotalcite is preferably 1-250 m ² /g, and more preferably 5-200 m ² /g. The BET specific surface area of semi-sintered hydrotalcite can be calculated by the BET multi-point method using a specific surface area measuring device (Macsorb HM Model 1210 manufactured by Mountech) and adsorbing nitrogen gas on the sample surface.

The average particle size of semi-sintered hydrotalcite is preferably 1-1,000nm, and more preferably 10-800nm. The average particle size of semi-sintered hydrotalcite is the median diameter of the particle size distribution when the particle size distribution is made on a volume basis by laser diffraction scattering particle size distribution measurement (JIS Z 8825).

Semi-sintered hydrotalcite can be surface treated with a surface treatment agent. Examples of the surface treatment agent used for the surface treatment include higher fatty acids, alkyl silanes, and silane coupling agents. Among them, higher fatty acids and alkyl silanes are particularly suitable. One or more surface treatment agents can be used.

Examples of the higher fatty acid include stearic acid, montanic acid, myristic acid, palmitic acid, and the like, and stearic acid is particularly preferred. One or more of these can be used.

Examples of the alkylsilane include methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, dimethyldimethoxysilane, octyltriethoxysilane, n-octadecyldimethyl(3-(trimethoxysilyl)propyl)ammonium chloride, etc. These may be used alone or in combination.

Examples of the silane coupling agent include epoxy-based silane coupling agents such as 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyl(dimethoxy)methylsilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; 3-butylpropyltrimethoxysilane, 3-butylpropyltriethoxysilane, 3-butylpropylmethyl 1-Aminopropyltrimethoxysilane, 11-Aminopropyltrimethoxysilane, 11-Aminopropyltriethoxysilane, 11-Aminopropyltrimeth ... Amine-based silane coupling agents such as (aminoethyl)-3-aminopropyl dimethoxymethyl silane; urea-based silane coupling agents such as 3-ureidopropyl triethoxy silane; vinyl-based silane coupling agents such as vinyl trimethoxy silane, vinyl triethoxy silane and vinyl methyl diethoxy silane; styrene-based silane coupling agents such as p-styrene trimethoxy silane; 3-acryloxypropyl trimethoxy silane Silane coupling agents include acrylate-based silane coupling agents such as 3-isocyanatepropyltrimethoxysilane, bis(triethoxysilylpropyl)disulfide, bis(triethoxysilylpropyl)tetrasulfide, and phenyltrimethoxysilane, methacryloyloxypropyltrimethoxysilane, imidazole silane, triazine silane, and the like. One or more of these may be used.

The surface treatment of the semi-sintered hydrotalcite can be carried out, for example, by stirring and dispersing the untreated semi-sintered hydrotalcite at room temperature with a mixer, and at the same time adding the surface treatment agent by spraying and stirring for 5 to 60 minutes. As the mixer, a generally known mixer can be used, for example, a V-type blender, a belt blender, a bubble cone blender, a Henschel mixer, a concrete mixer, a ball mill, a coarse grinding mill, etc. can be cited. In addition, when the semi-sintered hydrotalcite is pulverized with a ball mill, the aforementioned higher fatty acid, alkyl silane or silane coupling agent can be added to carry out the surface treatment. The amount of the surface treatment agent used varies depending on the type of semi-sintered hydrotalcite or the type of the surface treatment agent, but is preferably 1 to 10 parts by mass for 100 parts by mass of the semi-sintered hydrotalcite that has not been surface treated. In the present invention, the semi-sintered hydrotalcite that has been surface treated is also included in the "semi-sintered hydrotalcite".

The amount of the semi-sintered hydrotalcite is not particularly limited. From the viewpoint of the moisture shielding property of the sealing sheet, when the semi-sintered hydrotalcite is used, the amount is preferably 3 to 50 mass %, more preferably 5 to 45 mass %, and even more preferably 10 to 40 mass % per the total amount of the resin composition layer (that is, the total amount of non-volatile components per resin composition).

Examples of semi-sintered hydrotalcites include "DHT-4C" (manufactured by Kyowa Chemical Industry Co., Ltd., average particle size: 400 nm) and "DHT-4A-2" (manufactured by Kyowa Chemical Industry Co., Ltd., average particle size: 400 nm). Examples of sintered hydrotalcites include "KW-2200" (manufactured by Kyowa Chemical Industry Co., Ltd., average particle size: 400 nm), and examples of unsintered hydrotalcites include "DHT-4A" (manufactured by Kyowa Chemical Industry Co., Ltd., average particle size: 400 nm).

The resin composition layer may also contain other components different from the above-mentioned olefin resin, epoxy resin and semi-sintered hydrotalcite. There is no limitation on the other components, and generally known components of the resin composition for sealing can be used. Examples of other components include hardeners, hardening accelerators, other resins different from olefin resins and epoxy resins, other inorganic fillers different from semi-sintered hydrotalcite, and silane coupling agents. These other components may be only one or more.

When using an olefinic resin and/or an epoxy resin having an epoxy group, it is desirable to use a hardener, or to use a hardener and a hardening accelerator in combination for the hardening.

In the present invention, the resin composition layer may also include other resins different from the olefinic resin and the epoxy resin. Examples of other resins include tackifying resins and thermoplastic resins different from the olefinic resin (e.g., phenoxy resins). Phenoxy resins may have epoxy groups, similar to epoxy resins. The epoxy equivalent of the phenoxy resin is preferably greater than 5,000 and less than 16,000, and more preferably greater than 10,000 and less than 16,000.

In the present invention, the resin composition layer may also contain other inorganic fillers different from the semi-sintered hydrotalcite. Examples of other inorganic fillers include unsintered hydrotalcite, sintered hydrotalcite, talc, silica, aluminum oxide, barium sulfate, clay, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, and the like. The amount of other inorganic fillers is the total amount of each resin composition layer (that is, the total amount of non-volatile matter in each resin composition), preferably 0-12% by mass, more preferably 0-10% by mass, and even more preferably 0-8% by mass.

The thickness of the resin composition layer is preferably 5 to 75 μm, more preferably 10 to 50 μm, and even more preferably 15 to 50 μm.

For example, the sealing sheet of the present invention can be manufactured by coating and drying a resin composition varnish on a first film (support) to form a resin composition layer, and laminating a second film (covering film) on the obtained resin composition layer.

The resin composition varnish is prepared by mixing the components of the resin composition with an organic solvent using a kneading drum or a rotary mixer. The non-volatile matter of the resin composition varnish is preferably 20 to 80% by mass, more preferably 30 to 70% by mass.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetates such as ethyl acetate, butyl acetate, acetic acid solvent, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as solvent and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and aromatic mixed solvents such as solvent oil. In addition, as commercial products of aromatic mixed solvents, examples include "Swasol" (manufactured by Maruzen Oil Co., Ltd.) and "Ipsol" (manufactured by Idemitsu Kosan Co., Ltd.). The organic solvent may be only one kind or two or more kinds.

The drying conditions for forming the resin composition layer are not particularly limited, but the drying temperature is, for example, 80 to 130° C., and the drying time is, for example, 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 resin, the drying temperature is preferably 80 to 130° C., and the drying time is preferably 15 to 60 minutes.

A sealing sheet can be manufactured by forming a resin composition layer on a first film and then laminating a second film on the resulting resin composition layer. A sealing sheet can also be manufactured by forming a resin composition layer on a second film and then laminating a first film on the resulting resin composition layer. For lamination, generally known machines such as a roll laminator, a punch, a vacuum press laminator, etc. can be used. [Example]

The present invention is described in more detail below with reference to embodiments. However, the present invention is not limited to the embodiments below, and can be implemented with appropriate modifications within the scope of the above and below purposes, all of which are included in the technical scope of the present invention.

<Film> The moisture-proof films and PET films with release layers used in the following embodiments and comparative examples, and the WVTR measured by the method described below are shown in the following Table 1.

In Examples 1 to 5 and Comparative Example 1, a sealing film is prepared, and the sealing film is based on the premise that the first film (support body) and the second film (covering film) are peeled off before or after the formation of the sealing layer (resin composition layer or the hardened layer) of the organic EL device. In the sealing film of the embodiment, the following moisture-proof film with a release layer is used, and the moisture-proof film with a release layer is a first film and a second film together, and a release layer is formed on the opposite side of the barrier layer of the moisture-proof film in Table 1 above. "Film A with polysilicone release layer": A moisture-proof film with a polysilicone release layer is provided on the surface opposite to the barrier layer of film A. "PET + Film A with alkyd release layer": a moisture-proof film (the thickness of the entire film is 55μm) in which the opposite side of the release layer of PET with alkyd release layer is bonded to the opposite side of the barrier layer of Film A with an adhesive. 　　"PET + Film A with silicone release layer": a moisture-proof film (the thickness of the entire film is 55μm) in which the opposite side of the release layer of PET with silicone release layer is bonded to the opposite side of the barrier layer of Film A with an adhesive. "PET with silicone release layer + film B": a moisture-proof film (the thickness of the entire film is 55μm) in which the release layer of PET with silicone release layer is bonded to the opposite side of the barrier layer of film B with an adhesive. 　　"PET with silicone release layer + film C": a moisture-proof film (the thickness of the entire film is 55μm) in which the release layer of PET with silicone release layer is bonded to the opposite side of the barrier layer of film C with an adhesive. "Film D with a silicone release layer": A moisture-proof film with a silicone release layer is provided on the surface opposite to the barrier layer (aluminum foil) of film D (the thickness of the entire film is 55μm). 　　Also, the "PET with a silicone release layer" used in the comparative examples and the exemplary embodiments is a film with a silicone release layer provided on one side of a polyethylene terephthalate film. 　　Also, the "PET with an alkyd release layer" used in the comparative examples and the exemplary embodiments is a film with an alkyd release layer provided on one side of a polyethylene terephthalate film.

<Manufacturing of resin composition varnish> Manufacturing Example 1: Manufacturing of olefin resin composition varnish 　　In 130 parts by mass of 60 mass % Swasol solution of a saturated hydrocarbon resin containing cyclohexane ("Alcon P125" manufactured by Arakawa Chemicals Co., Ltd.), 35 parts by mass of liquid polyisobutylene modified with maleic anhydride ("HV-300M" manufactured by Toho Chemical Industries, Ltd.), 60 parts by mass of polybutene ("HV-1900" manufactured by JX Energy Co., Ltd.) and 100 parts by mass of semi-sintered hydrotalcite ("DHT-4C" manufactured by Kyowa Chemical Industries, Ltd.) were dispersed using a three-roll mill to obtain a mixture. 200 parts by weight of a 20% by weight Swasol solution of a polypropylene-polybutene copolymer modified with glycidyl methacrylate ("T-YP341" manufactured by Starlight PMC), 0.5 parts by weight of anionic polymerization hardener (2,4,6-tris(diaminomethyl)phenol) and 16 parts by weight of toluene were mixed into the obtained mixture, and the obtained mixture was uniformly dispersed in a high-speed rotary mixer to obtain an olefin resin composition varnish.

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

The above-mentioned ionic liquid hardener (tetrabutylphosphonium N-acetylglycine) was synthesized by the following procedure. 3.54 g of N-acetylglycine (Tokyo Chemical Industry Co., Ltd.) was added to 20.0 g of a 41.4 mass% aqueous solution of tetrabutylphosphonium hydroxide (produced by Hokko Chemical Industry Co., Ltd.) at 0°C, and stirred for 10 minutes. The mixture was depressurized to 40-50 mmHg using an evaporator, and concentrated at 60-80°C for 2 hours and at 90°C for 5 hours. The mixture was dissolved again in 14.2 ml of ethyl acetate (produced by Junsei Chemical Co., Ltd.) at room temperature, depressurized to 40-50 mmHg using an evaporator, and concentrated at 70-90°C for 3 hours. 11.7 g (purity: 96.9 mass %) of N-acetylglycine tetrabutylphosphonium salt was obtained as an oily compound.

<Manufacturing of Sealing Sheet> Example 1: PET+film A with a silicone release layer is used as the first film, and film A with a silicone release layer is used as the second film. The olefin resin composition varnish obtained in Manufacturing Example 1 is evenly applied to the release layer of the first film using a mold coater, and heated at 130°C for 60 minutes to obtain a sealing sheet having a resin composition layer with a thickness of 20 μm (the amount of residual solvent in the resin composition layer: about 1 mass %). Next, the obtained sealing sheet was rolled up into a roll while the resin composition layer of the obtained sealing sheet was in contact with the release layer of the second film. The rolled sealing sheet was cut into 507 mm lengthwise to obtain a sealing sheet with a size of 507×336 mm. The composition of the obtained sealing sheet is shown in Table 2 below.

Examples 2 to 10 and Comparative Examples 1 to 3 The films shown in Tables 2 and 3 below were used as the first film or the second film. The sealing sheets of Examples 2 to 10 and Comparative Examples 1 to 3 (the thickness of the resin composition layer was 20 μm) were manufactured in basically the same manner as in Example 1, except that the olefin resin composition varnish or epoxy resin composition varnish obtained in Preparation Example 1 or 2 was used to form the resin composition layer. The composition of the obtained sealing sheets is shown in Tables 2 and 3 below.

In Example 10 and Comparative Example 3 using the epoxy resin composition varnish, after the epoxy resin composition varnish was applied, it was dried at 80-100° C. (90° C. on average) for 5 minutes to form an epoxy resin composition layer (the amount of residual solvent in the resin composition layer: about 2 mass %).

In Examples 6 to 10 and Comparative Examples 2 and 3 in which a film X or a film E without a release layer is used as the first film, the resin composition layer on the second film is in contact with the barrier layer of the first film, and the sealing sheet is rolled up into a roll while these are attached.

<Measurement method> (1) Measurement of water vapor permeability (WVTR) The water vapor permeability of Film A to Film X, silicone peel-treated PET and alkyd peel-treated PET listed in Table 1 was measured in the following manner. First, a test piece of 60 mm φ was punched out from the film. According to JIS Z 0208:1976, 7.5 g of calcium chloride was measured in an aluminum permeable cup with a permeable area of 2.826×10 ^-3 m ² (60 mm φ), and the test piece was mounted in the permeable cup. Calcium chloride was placed in the permeable cup, and the initial mass of the test piece mounted in the permeable cup was measured using a precision balance. Next, place the above-mentioned permeable cup in a constant temperature test room at 40℃ and 90%RH for 24 hours, then put calcium chloride in it and measure the mass of the permeable cup with the test piece installed after permeation with a precision balance. The mass increase (= mass after permeation - initial mass) is set as the water vapor permeation, and the water vapor permeability (g/ ^m2 /24hr) is calculated from the water vapor permeation, permeation area and standing time.

(2) Determination of moisture content 1 The moisture content of the resin composition layer of the sealing sheets manufactured in Examples 1 to 5 and Comparative Example 1 before and after being placed was determined in the following manner.

First, the sealing sheet within 8 hours after production was cut into 7 cm squares, and the resin composition layer obtained by peeling off the first and second films was used as a sample before storage. The water content was measured using a Karl Fischer moisture measuring device ("Trace Moisture Measuring Device CA-200" manufactured by Mitsubishi Chemical Analytech) using electrometric titration. The moisture content before storage is shown in the following Table 2.

The device is composed of a glass container for placing a heatable sample and a titration device for titrating a reaction liquid containing water vaporized when the heated sample is heated. The vaporized water is moved from the glass container to the reaction liquid side of the titration device by a nitrogen flow rate of 250±25ml/min. The measurement is performed by placing a sample in a glass container replaced with a nitrogen environment (water vapor content <0.1ppm (mass standard)), titrating the amount of vaporized water at 130℃, and calculating the water content of the resin composition layer. The unit "ppm" of the water content listed below is the mass standard.

In addition, the sealing sheet cut into 7 cm square was placed in an environment of temperature 25°C and humidity 50% RH for 7 days, and the resin composition layer obtained by peeling off the first and second films was used as a sample after the placement in the same manner as above, and the water content was measured in the same manner. The water content after the placement is shown in the following Table 2.

The ratio of the measured water content after placement to the water content before placement (i.e., water content after placement/water content before placement, hereinafter referred to as "water content ratio") is calculated in the above manner. This ratio is also shown in Table 2 below.

The sealing sheet is evaluated based on the moisture content after placement and the ratio of the moisture content after placement to the moisture content before placement using the following criteria. The results are also shown in the table below. (Moisture content criteria) ○ (Good): The moisture content after placement is less than 9000ppm, and the moisture content ratio is less than 1.5. △ (Acceptable): The moisture content after placement is less than 9000ppm, and the moisture content ratio is 1.5 or more, or the moisture content after placement is more than 9000ppm, and the moisture content ratio is less than 1.5. × (Poor): The moisture content after placement is more than 9000ppm, and the moisture content ratio is 1.5 or more.

(3) Determination of moisture content 2 The same method as the determination of moisture content 1 was used except that the sealing sheets of Examples 6 to 10 and Comparative Examples 2 and 3 (i.e., the laminate of the resin composition layer and the first film cut into 7 cm squares) obtained by peeling off the second film were used as samples for moisture content determination. The moisture content before and after being placed was measured, and the moisture content ratio was calculated and evaluated based on the above-mentioned criteria. These results are shown in the following Table 3.

(4) Determination of the time when the luminous area starts to decrease In the manner described below, the organic EL element is sealed using the sealing sheets before and after the placement of Examples 1, 2, 4, 7 and 8, and Comparative Examples 1 to 3, and the time when the luminous area starts to decrease is measured for evaluation. In addition, as the sealing sheet before placement, a sealing sheet used within 24 hours after production is used. In addition, as the sealing sheet after placement, a sealing sheet that has been placed in an environment of temperature 25°C and humidity 50% RH for 7 days is used.

In Examples 1, 2, and 4 and Comparative Example 1, the sealing sheet used was a sealing sheet of PET luck AL1N30, the first film was peeled off, and the organic EL element was sealed in the manner described below. In Examples 7 and 8 and Comparative Examples 2 and 3, the sealing sheet used was a sealing sheet (i.e., a laminate of the resin composition layer and the first film) from which the second film was peeled off, and the organic EL element was sealed in the manner described below.

Wash a 25 mm x 25 mm square of alkali-free glass with boiled isopropyl alcohol for 5 minutes and dry it at 150°C for more than 30 minutes. Using a mask set at a distance of 4 mm from the end, hexazotriphenylcarbonitrile (HATCN) (thickness 10 nm), 9,9'-diphenyl-6-(9-phenyl)-9H-carbazole-3-yl)-9H,9'H-3,3'-biscarbazole (TrisPCz) (thickness 40 nm), 5 mass% 9,10-bis(N,N-di-p-tolylamino)anthracene (TTPA)-tris(8-hydroxyquinoline)aluminum (Alq3) (thickness 30 nm), tris(8-hydroxyquinoline)aluminum (Alq3) (thickness 30 nm), LiF (thickness 0.5 nm), and Mg-Ag (thickness 5 nm) were evaporated on the above-mentioned glass in the following order to obtain an organic EL device element.

Next, an inorganic film (SiN) (500 nm thick) was deposited on the organic EL device element by capacitively coupled plasma (CCP) to obtain an organic EL device element with an inorganic film. In a glove box, the resin composition layer of the sealing sheet and the organic EL device element with an inorganic film were bonded together by a thermal laminator (LamipackerDAiSY A4 (LPD2325) manufactured by FUJiPLA) to obtain an evaluation sample in which the organic EL device with an inorganic film was sealed with a sealing sheet.

Regarding the evaluation sample of the inorganic film-attached organic EL element sealed with the sealing sheet of Comparative Example 3 having an epoxy resin composition layer, the sample was heated at 100° C. for 60 minutes after bonding to cure the epoxy resin composition layer.

Using a KEYENCE microscope, the luminous area of the evaluation sample excluding the dark spot was calculated and this value was set as the initial value.

Next, the evaluation sample was stored in a small environmental tester (SH-222 manufactured by espec) set at a temperature of 85°C and a humidity of 85%RH for a specific period of time, and the luminous area of the evaluation sample was measured every specific hour.

The time when the luminous area of the evaluation sample stored in the small environmental tester becomes less than 95% of the initial value is calculated as the start time of the luminous area reduction, and the evaluation is performed according to the following criteria. The lower the water content of the resin composition layer of the sealing sheet, the longer the start time of the luminous area reduction becomes. The results are shown in the following Tables 2 and 3. In addition, the examples and comparative examples in which the start time of the luminous area reduction was not measured are recorded as "-" in the following Tables 2 and 3. (Criteria for the start time of the luminous area reduction) ○ (Good): The luminous area reduction started more than 1000 hours △ (Acceptable): The luminous area reduction started more than 800 hours but less than 1000 hours × (Poor): The luminous area reduction started less than 800 hours

As shown in Tables 2 and 3, the sealing sheet having the first and second films with WVTR of 1 (g/m ² /24hr) or less can suppress the water absorption (i.e., increase in water content) of the resin composition layer even when placed in an environment of 25°C and 50%RH for 7 days. The use of such a sealing sheet can extend the life of the organic EL device (the time when the light-emitting area starts to decrease). [Industrial Applicability]

The sealing sheet of the present invention is used for sealing electronic parts such as organic EL elements.

This case is based on Japanese Patent Application No. 2017-065143, which has been filed in Japan, and all of its contents are included in this specification.

Claims (13)

A sealing sheet having a first film, a resin composition layer and a second film, wherein the resin composition layer comprises an olefinic resin having an epoxy group and/or an epoxy resin, the resin composition layer is present between the first film and the second film, the water vapor permeability of the first film and the second film is respectively less than 1 (g/m ² /24hr), and the first film and the second film are films having a substrate and a barrier layer, the second film has a release layer and is a cover film to be peeled off during sealing, and when the first film is mounted on a device, the first film is a support body that is not peeled off, and the water vapor permeability of the first film is less than 0.01 (g/m ² /24hr), and the water vapor permeability of the second film is 0.01 (g/m ² /24hr) or more and 1 (g/m ² /24hr) or less. The sealing sheet according to claim 1, wherein the water vapor permeability of the first film is 0.005 (g/m ² /24hr) or less. The sealing sheet according to claim 1, wherein the water vapor permeability of the first film is 0.001 (g/m ² /24hr) or less. The sealing sheet according to claim 1, wherein the water vapor permeability of the first film is 0.0005 (g/m ² /24hr) or less. The sealing sheet according to any one of claims 1 to 4, wherein the water vapor permeability of the second film is 0.01 (g/m ² /24hr) or more and 0.5 (g/m ² /24hr) or less. The sealing sheet according to any one of claims 1 to 4, wherein the water vapor permeability of the second film is 0.01 (g/m ² /24hr) or more and 0.2 (g/m ² /24hr) or less. The sealing sheet according to any one of claims 1 to 4, wherein the water vapor permeability of the second film is 0.05 (g/m ² /24hr) or more and 0.2 (g/m ² /24hr) or less. A sealing sheet having a first film, a resin composition layer and a second film, wherein the resin composition layer comprises an olefinic resin having an epoxy group and/or an epoxy resin, the resin composition layer is present between the first film and the second film, the water vapor permeability of the first film and the second film is respectively less than 1 (g/m ² /24hr), and the first film and the second film are films having a substrate and a barrier layer, the second film has a release layer and is a cover film to be peeled off during sealing, and when the first film is mounted on a device, the first film is a support body that is not peeled off, and the water vapor permeability of the first film is 0.0005 (g/m ² The water vapor permeability of the second film is more than 0.0005 (g/m ² /24hr) and less than 0.01 (g/m ² /24hr). A sealing sheet as claimed in any one of claims 1 to 4 and 8, wherein the substrate is a plastic film. A sealing sheet as claimed in any one of claims 1 to 4 and 8, wherein the barrier layer comprises an inorganic film. A sealing sheet as claimed in any one of claims 1 to 4 and 8, wherein the resin composition layer contains semi-sintered hydrotalcite. A sealing sheet as claimed in any one of claims 1 to 4 and 8, wherein the first film is a film having a release layer. The sealing sheet as in any one of claim items 1 to 4 and 8 is used for sealing an organic EL element.