Sealing sheet

Abstract

The present application provides a sealing sheet which is a sealing sheet having a layered structure comprising, in order, a first sheet, a resin composition layer, a second sheet, and a third sheet, wherein the water vapor permeability of the first sheet and the third sheet is each independently 1 (g / m 2 / 24 hr) or less, the water vapor permeability of the second sheet is 10 (g / m 2 / 24 hr) or more, and the third sheet can be peeled off.

Description

Technical Field

[0001] This invention relates to sealing sheets that can be used for sealing electronic devices. Background Technology

[0002] Organic EL (Electroluminescence) devices, solar cells, and other electronic devices suffer from poor moisture resistance, leading to reduced brightness and efficiency due to moisture. To protect these devices, sealing sheets containing resin compositions are used to seal the components.

[0003] Sealing sheets with a moisture-containing resin composition layer cannot adequately protect electronic devices. Therefore, Patent Document 1 proposes a sealing sheet that includes a first moisture-proof film, a resin composition layer, and a second moisture-proof film to suppress moisture absorption of the resin composition layer during storage.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: International Publication No. 2018 / 181426. Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] As described in Patent Document 1, a sealing sheet with a structure having moisture-proof films on both sides of a resin composition layer cannot effectively dry the resin composition layer because the moisture-proof films hinder the removal of moisture from the resin composition layer. Furthermore, when drying the sheet exposed to the resin composition layer after peeling off the second moisture-proof film from the aforementioned sealing sheet, the resin composition layer may be contaminated during the drying process.

[0009] The present invention was made with regard to the matters described above, and its object is to provide a sealing sheet that can effectively dry a resin composition layer and prevent contamination of the resin composition layer during the drying process.

[0010] Technical solutions for solving technical problems

[0011] The present invention, which can achieve the above objectives, is described below;

[0012] [1] A sealing sheet having a laminated structure, the laminated structure sequentially comprising a first sheet, a resin composition layer, a second sheet, and a third sheet.

[0013] The water vapor transmission rates of the first and third sheets are each independently 5 g / m². 2 ( / 24hr) or less,

[0014] The water vapor transmission rate of the second sheet is 10 (g / m²). 2 (24hr) or more, and the third sheet can be peeled off;

[0015] [2] The sealing sheet described in [1] above, wherein the 90-degree peel strength between the second sheet and the third sheet is above 0.1 gf / inch and below 250 gf / inch;

[0016] [3] The sealing sheet described in [1] or [2] above, wherein the third sheet is a sheet having an adhesive layer, and the adhesive layer is in contact with the second sheet;

[0017] [4] The sealing sheet described in any one of [1] to [3] above, wherein the second sheet is a sheet having a release layer, and the release layer is in contact with the resin composition layer;

[0018] [5] The sealing sheet according to any one of [1] to [4] above, wherein the first sheet is a sheet having a release layer, and the release layer is in contact with the resin composition layer;

[0019] [6] The sealing sheet as described in any one of [1] to [5] above, wherein the resin composition layer comprises semi-calcined hydrotalcite;

[0020] [7] The sealing sheet described in any one of [1] to [6] above is a sheet used for sealing electronic devices;

[0021] [8] The sealing sheet described above [7], wherein the electronic device is an organic EL device, a quantum dot device or a solar cell.

[0022] The effects of the invention

[0023] The sealing sheet of the present invention can effectively dry the resin composition layer, and can prevent contamination of the resin composition layer during the drying process. Detailed Implementation

[0024] The sealing sheet of the present invention is a sealing sheet having a laminated structure, wherein the laminated structure sequentially comprises a first sheet, a resin composition layer, a second sheet, and a third sheet.

[0025] One feature of this invention is that the water vapor transmission rate (WVTR) of the first sheet and the third sheet is each independently 5 g / m². 2 The first and third sheets are moisture-proof sheets (approximately 24 hours or less). Furthermore, one feature of this invention is that the water vapor transmission rate of the second sheet is 10 g / m³. 2(24hr) or more, meaning the second sheet is a non-moisture-proof sheet. Furthermore, one feature of this invention is that a third sheet can be peeled off.

[0026] The sealing sheet of the present invention, having the configuration described above, allows for efficient drying of the resin composition layer by peeling off the third sheet, which serves as a moisture-proof sheet, before drying, while protecting the resin composition layer with the second sheet, which serves as a non-moisture-proof sheet. It should be noted that after the resin composition layer has dried, the peeled-off third sheet or a new third sheet can be laminated onto the second sheet.

[0027] The first, second, and third sheets can all have single-layer or laminated structures, with laminated structures being preferred. The first and third sheets, as moisture-proof sheets, are more preferably sheets having a laminated structure including a barrier layer and a substrate. The second sheet, as a non-moisture-proof sheet, can be a sheet composed solely of a substrate, or a sheet having a laminated structure including a release layer and a substrate.

[0028] The WVTR of the first and third sheets is independently preferably 4 (g / m²). 2 / 24hr) or less. The lower limit of the WVTR of the first and third sheets is not particularly limited, but is preferably lower. Ideally, the WVTR of the first and third sheets is most preferably 0 (g / m²). 2 / 24hr). WVTR is a value measured by the method described in the embodiments described later.

[0029] For example, when using the sealing sheet of the present invention to seal electronic devices, without peeling off the first sheet and using it as a highly moisture-resistant layer in the electronic device, it is preferable to use a WVTR of less than 0.01 (g / m²) for the first sheet of the present invention. 2 A moisture-proof sheet material (24hr). The preferred WVTR of this sheet material is 0.005 (g / m²). 2 ( / 24hr) or less, more preferably 0.001 (g / m 2 ( / 24hr) or less, particularly preferably 0.0005 (g / m 2 The lower limit of the WVTR of this sheet is not particularly limited, but a lower value is preferred. Ideally, the WVTR is 0 (g / m²). 2 / 24hr).

[0030] The third sheet is peeled off before the resin composition layer dries. Therefore, from the viewpoint of simultaneously suppressing water absorption of the resin composition layer during storage and reducing the manufacturing cost of the sealing sheet, a WVTR of 0.01 (g / m²) is preferred as the third sheet. 2 ( / 24hr) or more and 1 (g / m2 A moisture-proof sheet material with a moisture resistance of less than 24 hours. Considering the balance between moisture resistance and cost, the WVTR of this sheet material is 0.05 (g / m²). 2 ( / 24hr) or more, more preferably 0.8 (g / m 2 ( / 24hr) or less, more preferably 0.6 (g / m 2 ( / 24hr) or less.

[0031] The preferred WVTR for the second sheet is 15 (g / m²). 2 / 24hr) or above. There is no specific upper limit, but the WVTR of the second sheet is typically 20,000 (g / m²). 2 ( / 24hr) or less, preferably 15,000 (g / m 2 ( / 24hr) or less.

[0032] For both the first and third sheets, when using opaque moisture-proof sheets such as those with metal foil, quality inspection of the resin composition layer becomes difficult. Therefore, if one of the first and third sheets uses an opaque moisture-proof sheet, the other should ideally use a transparent moisture-proof sheet. The transparency of a transparent moisture-proof sheet depends on its thickness, and the total light transmittance at D65 light is expected to be 85% or higher. An "opaque moisture-proof sheet" is defined as a "moisture-proof sheet with a total light transmittance of 50% or less at D65 light." For total light transmittance, a Suga Haze Meter HZ-V3 (halogen lamp) can be used, with air as a reference, to measure at D65 light.

[0033] In the structure of an electronic device that uses the sealing sheet of the present invention to seal organic EL elements, when an inorganic film is directly provided on the sealing layer formed of a resin composition layer, or when a high moisture-proof layer is not required and is not provided, the first sheet and the third sheet preferably have a WVTR of 0.01 (g / m²). 2 ( / 24hr) or more and 1 (g / m 2 / 24hr) or less moisture-proof sheet.

[0034] The substrate can be a single-layer structure or a multilayer structure. Examples of substrates include: polyolefins such as polyethylene, polypropylene (PP), and polymethylpentene; polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); and plastic films such as polycarbonate (PC), polyimide (PI), cyclic olefin polymers (COP), and polyvinyl chloride. Only one type of plastic film can be used, or two or more types can be used. The substrate is preferably a polyethylene terephthalate film, a cyclic olefin polymer film, a polyethylene naphthalate film, or a polycarbonate film, more preferably a polyethylene terephthalate film or a cyclic olefin polymer film. The thickness of the substrate is preferably 10–100 μm, more preferably 10–75 μm, and even more preferably 10–50 μm.

[0035] Examples of barrier layers include inorganic films such as metal foil (e.g., aluminum foil), silicon dioxide vapor-deposited films, silicon nitride films, and silicon oxide films. The barrier layer can be composed of multiple layers of inorganic films (e.g., metal foil and silicon dioxide vapor-deposited films). Furthermore, the barrier layer can be composed of organic and inorganic materials, and can be a composite multilayer of organic and inorganic films. The thickness of the barrier layer is preferably 0.01–100 μm, more preferably 0.05–50 μm, and even more preferably 0.05–30 μm.

[0036] WVTR is less than 0.01 (g / m 2 Moisture-resistant sheets (24hr), especially those with a WVTR of 0.005 (g / m²). 2 Moisture-proof sheets (24 hours or less) can be manufactured, for example, by using chemical vapor deposition (CVA) methods (e.g., CVA using heat, plasma, ultraviolet light, vacuum heat, vacuum plasma, or vacuum ultraviolet light) or physical vapor deposition (e.g., vacuum evaporation, sputtering, ion plating, laser deposition, molecular beam epitaxy) to laminate inorganic films such as silicon dioxide, aluminum oxide, magnesium oxide, silicon nitride, silicon oxynitride, SiCN, and amorphous silicon onto a substrate surface in single or multiple layers (see, for example, Japanese Patent Application Publication No. 2016-185705, Japanese Patent No. 5719106, Japanese Patent No. 5712509, and Japanese Patent No. 5292358). To prevent cracking of the inorganic film, it is preferable to alternately laminate the inorganic film with a transparent planarization layer (e.g., a transparent plastic layer). Moisture-proof sheets manufactured using this method are transparent sheets.

[0037] In addition to moisture-proof sheets manufactured using the methods described above, examples include metal foils such as SUS foil and aluminum foil, or moisture-proof sheets manufactured by bonding a substrate and a metal foil together with an adhesive. Metal foil, or moisture-proof sheets formed from a substrate and a metal foil, are typically opaque.

[0038] Furthermore, for moisture-proof sheets, the barrier layer can be manufactured using methods such as: depositing an inorganic film containing inorganic materials such as silicon dioxide, aluminum oxide, magnesium oxide, silicon nitride, silicon oxynitride, SiCN, or amorphous silicon onto the surface of a substrate by vapor deposition; or coating a substrate with a coating liquid formed of a metal oxide and a barrier-forming organic resin and then drying it (see, for example, Japanese Patent Application Publication No. 2013-108103 and Japanese Patent No. 4028353). Moisture-proof sheets manufactured using these methods are transparent.

[0039] Commercially available products can be used for moisture-proof sheets. Examples of such products include: Kuraray's "KURARISTER CI", Mitsubishi Resin's "TECHBARRIER HX", "TECHBARRIER LX" and "TECHBARRIER L"", Dai Nippon Printing's "IB-PET-PXB", Toppan Printing's "GL, GX series", Toyo Aluminum's "AL1N30 with PET", and Mitsubishi Resin's "X-BARRIER", etc.

[0040] Both the first and third sheets, as moisture-proof sheets, can have layers other than the substrate and the barrier layer. For example, a laminated sheet obtained by further bonding a substrate to a sheet having a laminated structure including a barrier layer and a substrate using an adhesive (e.g., a sheet having a laminated structure sequentially including a substrate, an adhesive layer, a barrier layer, and a substrate; or a sheet having a laminated structure sequentially including a substrate, an adhesive layer, a substrate, and a barrier layer) can be used as the first and / or third sheets. Examples of substrates described above can be cited as substrates. The adhesive used in this invention is not particularly limited, and commercially available adhesives can be used.

[0041] The first sheet may be a sheet without a release layer. Alternatively, the first sheet may be a sheet with a release layer, wherein the release layer is in contact with the resin composition layer. Examples of first sheets having a release layer include: sheets having a laminated structure sequentially comprising a barrier layer, a substrate, and a release layer; sheets having a laminated structure sequentially comprising a substrate, a barrier layer, and a release layer; and sheets having a laminated structure sequentially comprising a barrier layer, a substrate, an adhesive layer, a substrate, and a release layer. Examples of the substrate and barrier layer include those described above. The adhesive used in this invention is not particularly limited, and commercially available adhesives may be used.

[0042] The second sheet is a sheet having a release layer, and the aforementioned release layer is in contact with the resin composition layer; this is a preferred embodiment of the present invention. Examples of the second sheet having a release layer include, for example, a sheet having a laminated structure comprising a release layer and a substrate. Examples of substrates include those described above.

[0043] Regarding the release layer, it can be formed, for example, by applying a release agent to a substrate and then drying it. Alternatively, a plastic film with a release layer can be formed by applying a release agent to a plastic film and then drying it. Next, an adhesive is used to bond the plastic film with the release layer to the aforementioned moisture-proof sheet composed of a substrate and a barrier layer, thus forming a moisture-proof sheet with a release layer. The drying temperature after applying the release agent is, for example, 100–150°C, and the drying time is, for example, 5–120 minutes.

[0044] Examples of release agents include silicone-based release agents, alkyd resin-based release agents, fluorinated release agents, and olefin-based release agents. The release layer is preferably formed of a silicone-based or alkyd resin-based release agent. The thickness of the release layer is preferably 0.05–5 μm, more preferably 0.05–3 μm, and even more preferably 0.05–2 μm.

[0045] The thickness of the first sheet (when the first sheet is a laminated sheet, its overall thickness) is preferably 10–100 μm, more preferably 10–62.5 μm, and even more preferably 10–55 μm. The thickness of the second sheet (when the second sheet is a laminated sheet, its overall thickness) is preferably 5–50 μm, more preferably 7.5–40 μm, and even more preferably 10–40 μm. The thickness of the third sheet (when the third sheet is a laminated sheet, its overall thickness) is preferably 10–100 μm, more preferably 10–62.5 μm, and even more preferably 10–55 μm.

[0046] As described above, one feature of the present invention is that the third sheet can be peeled off before the resin composition layer dries. Examples of configurations for this purpose include, for instance:

[0047] (1) The third sheet is a sheet having an adhesive layer, and the aforementioned adhesive layer is in contact with the second sheet.

[0048] (2) The second sheet is a sheet having an adhesive layer, and the aforementioned adhesive layer is in contact with the third sheet.

[0049] In the aforementioned configuration (1), the second sheet may have a release layer. The configuration in which the third sheet is a sheet with an adhesive layer, the second sheet is a sheet with a release layer, and the aforementioned adhesive layer is in contact with the aforementioned release layer is included in the aforementioned configuration (1). The release layer is described as above.

[0050] Furthermore, in the aforementioned configuration (1), the second sheet may have release layers on both sides. The configuration includes the third sheet being a sheet with an adhesive layer, the second sheet being a sheet with release layers on both sides, the adhesive layer contacting one side of the release layer, and the other side of the release layer contacting the resin composition layer. The release layer is described above.

[0051] In the aforementioned configuration (2), the third sheet may have a release layer. The configuration in which the second sheet is a sheet with an adhesive layer, the third sheet is a sheet with a release layer, and the aforementioned adhesive layer is in contact with the aforementioned release layer is included in the aforementioned configuration (2).

[0052] Furthermore, in the aforementioned configuration (2), the third sheet may have release layers on both sides. The configuration in which the second sheet is a sheet with an adhesive layer, the third sheet is a sheet with release layers on both sides, and the aforementioned adhesive layer and the aforementioned release layer are in contact with one of them is included in the aforementioned configuration (2). The release layer is explained as described above.

[0053] Regarding the aforementioned configuration (2), after the third sheet is peeled off, an adhesive layer remains on the second sheet, and debris may adhere to it during drying. From these points of view, the aforementioned configuration (1) is preferred.

[0054] The 90-degree peel strength between the second and third sheets is preferably 0.1 gf / inch or more, more preferably 0.2 gf / inch or more, even more preferably 0.25 gf / inch or more, preferably 250 gf / inch or less, more preferably 200 gf / inch or less, and even more preferably 150 gf / inch or less. This 90-degree peel strength is a value measured by the method described in the examples described later.

[0055] When the sealing sheet of the present invention has the aforementioned configuration (1), the "90-degree peel strength between the second sheet and the third sheet" refers to the "90-degree peel strength between the adhesive layers of the second sheet and the third sheet". In this configuration, when the second sheet has a release layer and the aforementioned release layer is in contact with the adhesive layer of the third sheet, the "90-degree peel strength between the second sheet and the third sheet" refers to the "90-degree peel strength between the aforementioned release layer and the aforementioned adhesive layer".

[0056] When the sealing sheet of the present invention has the aforementioned configuration (2), "90-degree peel strength between the second sheet and the third sheet" refers to "90-degree peel strength between the adhesive layer of the second sheet and the third sheet". In this configuration, when the third sheet has a release layer and the aforementioned release layer is in contact with the adhesive layer of the second sheet, "90-degree peel strength between the second sheet and the third sheet" refers to "90-degree peel strength between the aforementioned release layer and the aforementioned adhesive layer".

[0057] The 90-degree peel strength between the resin composition layer and the second sheet is preferably greater than the 90-degree peel strength between the second sheet and the third sheet. This configuration prevents the second sheet from peeling off when the third sheet is peeled off. The 90-degree peel strength between the resin composition layer and the second sheet is preferably 0.2 gf / inch or more, more preferably 0.25 gf / inch or more, further preferably 0.30 gf / inch or more, preferably 300 gf / inch or less, more preferably 250 gf / inch or less, and further preferably 200 gf / inch or less.

[0058] When the second sheet has a release layer and the aforementioned release layer is in contact with the resin composition layer, the "90-degree peel strength between the resin composition layer and the second sheet" refers to the "90-degree peel strength between the aforementioned release layer and the resin composition layer".

[0059] The thickness of the adhesive layer is preferably 0.5 to 50 μm, more preferably 1 to 40 μm, and even more preferably 1 to 30 μm.

[0060] The adhesive layer can be formed using an adhesive. Well-known adhesives can be used. Preferred adhesives include, for example: KR-3704, X-40-3270-1, X-40-3323, X-40-3306, KR-100, KR-101-10, KR-130, KR-3700, KR-3701, X-40-3327, X-40-3240, X-40-3291-1 (all manufactured by Shin-Etsu Chemical Industry Co., Ltd.), TSR1512, TSR1516, YR3340, YR3286, PSA610-SM, and XR37-B90. 24. Silicone adhesives such as XR37-B6722 (all manufactured by Momentive Advanced Materials Co., Ltd.); butyl rubber adhesives such as BUTYL065, BUTYL268, BUTYL365, CHLOROBUTYL1066, BROMOBUTYL2222, BROMOBUTYL2244, BROMOBUTYL2255 (all manufactured by Nippon Butyl Corporation); RB100, RB402, RB301, RB101-3 (all manufactured by Lanxess Corporation); Tafcelene. Olefin elastomers such as X1102, X1104, X1105, and X1107 (all manufactured by Sumitomo Chemical Co., Ltd.); ARONTACK S-1511X, S-1511 Modified, S-3403, S-3452YKF, S-1601, and S-1605 (all manufactured by Toa Synthetic Co., Ltd.); Finetack CT-5020, CT-5030, SPS-900-LV, SPS-945NT, SPS-1040NT-25, CT-3088, CT-3850, and CT-6030 (all manufactured by DIC Corporation); SK-Dyne 1501BS4, RE-4, and RE-339 (all manufactured by Soken Chemical Co., Ltd.); and Kurarity. Acrylic adhesives such as LA3320, LA2330, LA2250, LA2270, and LA4285 (all manufactured by Kuraray Co., Ltd.) are examples. Furthermore, resin compositions prepared by appropriately adding alicyclic saturated hydrocarbon resins to various matrix polymers can also be used to form adhesive layers. Examples of matrix polymers include olefin elastomers such as Tafcelene X1102, X1104, X1105, and X1107 (all manufactured by Sumitomo Chemical Co., Ltd.), and styrene-based thermoplastic elastomers such as SEPTON 1020, 2002, 2004, 2005, 2006, 2063, 2104, 4033, 4044, 4055, 4077, and 4099 (all manufactured by Kuraray Co., Ltd.). Additionally, resin compositions containing the olefin resins described below can also be used to form adhesive layers. To form the adhesive layer, a resin composition that does not contain the semi-calcined hydrotalcite or other inorganic fillers described later may also be used.

[0061] For example, the adhesive layer can be formed by applying a liquid adhesive to a second or third sheet and then drying it. Alternatively, an adhesive varnish obtained by dissolving the adhesive in a solvent can be used in the formation of the adhesive layer.

[0062] In this invention, there are no particular limitations on the resin composition layer, and known resin compositions can be used to form the resin composition layer. For effective sealing of organic EL elements, the resin composition layer preferably comprises an olefinic resin and / or an epoxy resin.

[0063] Olefin resins can be of one type or two or more. There are no particular limitations on the olefin resin as long as it has a backbone derived from an olefin monomer. Preferred olefin resins are ethylene-based resins, propylene-based resins, butene-based resins, and isobutylene-based resins. These olefin resins can be homopolymers or copolymers such as random copolymers and block copolymers. Examples of copolymers include copolymers of two or more olefins, and copolymers of olefins with monomers other than olefins, such as non-conjugated dienes and styrene. Examples of preferred copolymers include ethylene-nonconjugated diene copolymers, ethylene-propylene copolymers, ethylene-propylene-nonconjugated diene copolymers, ethylene-butene copolymers, propylene-butene copolymers, propylene-butene-nonconjugated diene copolymers, styrene-isobutylene copolymers, and styrene-isobutylene-styrene copolymers. Preferred olefin resins include, for example, isobutylene-modified resins, styrene-isobutylene-modified resins, and modified propylene-butene resins.

[0064] From the viewpoint of imparting excellent physical properties such as adhesion, olefin resins preferably include at least one selected from olefin resins having an anhydride group (i.e., carbonyloxycarbonyl group (-CO-O-CO-)) and olefin resins having an epoxy group, and more preferably include olefin resins having an anhydride group and olefin resins having an epoxy group.

[0065] Examples of anhydride groups include those derived from succinic anhydride, maleic anhydride, and glutaric anhydride. Olefin resins containing anhydride groups can be obtained, for example, by grafting an olefin resin with an unsaturated compound containing anhydride groups under free radical reaction conditions. Alternatively, unsaturated compounds containing anhydride groups can be free radical copolymerized with olefins, etc. Similarly, olefin resins containing epoxy groups can be obtained, for example, by grafting an olefin resin with an epoxy group unsaturated compounds such as (meth)acrylate glycidyl ether, 4-hydroxybutylacrylate glycidyl ether, and allyl glycidyl ether under free radical reaction conditions. Alternatively, unsaturated compounds containing epoxy groups can be free radical copolymerized with olefins, etc.

[0066] The concentration of the anhydride group in the olefin resin containing the anhydride group is preferably 0.05–10 mmol / g, more preferably 0.1–5 mmol / g. The concentration of the anhydride group can be obtained from the acid value as described in JIS K 2501, whereby the acid value is defined as the number of mg of potassium hydroxide required to neutralize the acid present in 1 g of the resin. Furthermore, the amount of the olefin resin containing the anhydride group in the olefin resin is preferably 0–70% by mass, more preferably 10–50% by mass.

[0067] The concentration of epoxy groups in the olefin resin containing epoxy groups is preferably 0.05–10 mmol / g, more preferably 0.1–5 mmol / g. The epoxy group concentration is determined based on the epoxy equivalent obtained in JIS K 7236-1995. Furthermore, the amount of olefin resin containing epoxy groups in the olefin resin is preferably 0–70% by mass, more preferably 10–50% by mass.

[0068] From the viewpoint 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." With such olefin resins, the anhydride groups and epoxy groups react upon heating to form a cross-linked structure, thus forming a sealing layer (resin composition layer) with excellent moisture resistance. The cross-linking structure can be formed after sealing, but in cases where the object to be sealed, such as organic EL elements, is not highly heat-resistant, it is desirable to form the cross-linking structure beforehand during the manufacture of the sealing sheet. The ratio of the olefin resin having anhydride groups to the olefin resin having epoxy groups is not particularly limited, as long as a suitable cross-linking structure can be formed. 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.

[0069] The number-average molecular weight of the olefin-based resin is not particularly limited. From the viewpoint of providing good coatability of the resin composition varnish and good compatibility with other components in the resin composition, a number-average molecular weight of 1,000,000 or less is preferred, more preferably 750,000 or less, further 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 coating depressions during the application of the resin composition varnish, enabling the formed resin composition layer to exhibit moisture resistance, and improving mechanical strength, a number-average molecular weight of 1,000 or more is preferred, more preferably 3,000 or more, further preferably 5,000 or more, even more preferably 10,000 or more, even more preferably 30,000 or more, and particularly preferably 50,000 or more is preferred. It should be noted that the number-average molecular weight in this invention is determined by gel permeation chromatography (GPC) (polystyrene conversion). Specifically, based on the GPC-based number-average molecular weight, an LC-9A / RID-6A manufactured by Shimadzu Corporation can be used as the measuring apparatus, a Shodex K-800P / K-804L / K-804L manufactured by Showa Denko Corporation can be used as the column, and toluene or the like can be used as the mobile phase. The measurement is performed at a column temperature of 40°C, and the molecular weight is calculated using a standard curve of standard polystyrene.

[0070] From the viewpoint of suppressing the decrease in fluidity caused by the thickening of the varnish, olefin resins are preferably amorphous. Here, amorphous means that the olefin resin does not have a definite melting point; for example, an olefin resin in which no definite peak is observed when the melting point of the olefin resin is determined by DSC (differential scanning calorimetry) can be used.

[0071] The amount of olefin resin is not particularly limited. From the viewpoint of good coatability, when using olefin resin, its amount relative to the total amount of the resin composition layer (i.e., relative to the total amount of non-volatile components of the resin composition) is preferably 80% by mass or less, more preferably 75% by mass or less, further preferably 70% by mass or less, even more preferably 60% by mass or less, even more preferably 55% by mass or less, and particularly preferably 50% by mass or less. On the other hand, from the viewpoint of improving both moisture resistance and transparency, the amount of olefin resin relative to the total amount of the resin composition layer (i.e., relative to the total amount of non-volatile components of the resin composition) is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, even more preferably 7% by mass or more, even more preferably 10% by mass or more, particularly preferably 35% by mass or more, and most preferably 40% by mass or more.

[0072] Next, specific examples of olefin-based resins will be given. Specific examples of isobutylene-based resins include: BASF's "Oppanol B100" (viscosity-average molecular weight: 1,110,000) and BASF's "B50SF" (viscosity-average molecular weight: 400,000).

[0073] Specific examples of butene-based resins include: ENEOS Corporation's (formerly JXTG Energy) "HV-1900" (polybutene, number average molecular weight: 2,900) and Toho Chemical Industry Co., Ltd.'s "HV-300M" (a modified version of maleic anhydride-modified liquid polybutene ("HV-300" (number average molecular weight: 1,400"), number average molecular weight: 2,100, number of carboxyl groups constituting the anhydride group: 3.2 per molecule, acid value: 43.4 mg KOH / g, anhydride group concentration: 0.77 mmol / g).

[0074] Specific examples of styrene-isobutylene copolymers include: Kaneka's "SIBSTAR T102" (styrene-isobutylene-styrene block copolymer, number-average molecular weight: 100,000, styrene content: 30% by mass); Starlight PMC's "T-YP757B" (maleic anhydride-modified styrene-isobutylene-styrene block copolymer, anhydride group concentration: 0.464 mmol / g, number-average molecular weight: 100,000); and Starlight PMC's "T-YP766" (glycidyl methacrylate-modified styrene-isobutylene-styrene block copolymer, epoxy group concentration...). : 0.638 mmol / g, number average molecular weight: 100,000), "T-YP8920" (maleic anhydride modified styrene-isobutylene-styrene copolymer, anhydride concentration: 0.464 mmol / g, number average molecular weight: 35,800) manufactured by Xingguang PMC Company, and "T-YP8930" (glycidyl methacrylate modified styrene-isobutylene-styrene copolymer, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 48,700) manufactured by Xingguang PMC Company.

[0075] Specific examples of ethylene-based or propylene-based resins include: Mitsui Chemicals' "EPT X-3012P" (ethylene-propylene-5-ethylidene-2-norbornene copolymer), Mitsui Chemicals' "EPT1070" (ethylene-propylene-dicyclopentadiene copolymer), and Mitsui Chemicals' "TAFMERA4085" (ethylene-butene copolymer).

[0076] Specific examples of ethylene-methyl methacrylate copolymers include: a 20% by mass toluene solution of "T-YP429" (maleic anhydride-modified ethylene-methyl methacrylate copolymer, with a total of 100% by mass of methyl methacrylate units relative to ethylene units and methyl methacrylate units: 32% by mass, anhydride concentration: 0.46 mmol / g, number average molecular weight: 2,300) manufactured by Starlight PMC, and "T-YP430" (maleic anhydride-modified ethylene-methyl methacrylate copolymer, with a total of 100% by mass of methyl methacrylate units relative to ethylene units and methyl methacrylate units, in a toluene solution of 32% by mass, anhydride concentration: 0.46 mmol / g, number average molecular weight: 2,300) manufactured by Starlight PMC. The following are examples of solutions: 32% by mass of methyl methacrylate units, anhydride concentration of 1.18 mmol / g, number-average molecular weight of 4,500; "T-YP431" (a 20% by mass toluene solution of glycidyl methacrylate-modified ethylene-methyl methacrylate copolymer (epoxy group concentration: 0.64 mmol / g, number-average molecular weight: 2,400) manufactured by Starlight PMC; and "T-YP432" (a glycidyl methacrylate-modified ethylene-methyl methacrylate copolymer, epoxy group concentration: 1.63 mmol / g, number-average molecular weight: 3,100) manufactured by Starlight PMC.

[0077] Specific examples of propylene-butene copolymers include: a 20% Swasol solution of "T-YP341" (a propylene-butene random copolymer modified with glycidyl methacrylate (29% by mass of butene units relative to a total of 100% by mass of propylene and butene units, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 155,000) manufactured by Starlight PMC; "T-YP279" (a propylene-butene random copolymer modified with maleic anhydride (36% by mass of butene units relative to a total of 100% by mass of propylene and butene units, anhydride group concentration: 0.464 mmol / g, number average molecular weight: 35,000) manufactured by Starlight PMC; and "T-YP276" (a propylene-butene random copolymer modified with glycidyl methacrylate (29% by mass of butene units relative to a total of 100% by mass of propylene units, epoxy group concentration: 0.638 mmol / g, number average molecular weight: 155,000) manufactured by Starlight PMC. The following are examples of solutions: 40% by mass toluene solution of "T-YP312" (maleic anhydride modified propylene-butene random copolymer (29% by mass relative to propylene and butene units, anhydride concentration: 0.464 mmol / g, number average molecular weight: 60,900) manufactured by Starlight PMC; and 20% by mass toluene solution of "T-YP313" (glycidyl methacrylate modified propylene-butene random copolymer (29% by mass relative to propylene and butene units, epoxy concentration: 0.638 mmol / g, number average molecular weight: 155,000) manufactured by Starlight PMC.

[0078] When olefin resins include olefin resins having epoxy groups, olefin resins having functional groups other than acid anhydride groups that can react with epoxy groups can be used. Examples of such functional groups include hydroxyl, phenolic hydroxyl, amino, and carboxyl groups.

[0079] When olefin resins include olefin resins having an anhydride group, olefin resins having functional groups other than epoxy groups that can react with the anhydride group can be used. Examples of such functional groups include hydroxyl, primary or secondary amino, thiol, and oxetyl groups.

[0080] Epoxy resins can be used without restriction as long as they have an average of two or more epoxy groups per molecule. Examples of epoxy resins include: bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol type epoxy resin, naphthol type epoxy resin, bisphenol F type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy resin, and aromatic glycidylamine type epoxy resin (e.g., tetraglycidyl diaminodiphenylmethane, triglycidyl p-aminophenol, diglycidyl toluidine, diglycidyl...). Epoxy resins include oleo-based aniline, alicyclic epoxy resins, aliphatic chain epoxy resins, phenolic varnish-type epoxy resins, cresol phenolic varnish-type epoxy resins, bisphenol A phenolic varnish-type epoxy resins, epoxy resins with butadiene structures, diglycidyl ethers of bisphenol, diglycidyl ethers of naphthalene glycol, diglycidyl ethers of phenols, and diglycidyl ethers of alcohols, as well as alkyl-substituted, halogenated, and hydrides of these epoxy resins. Epoxy resins can be used alone or in combination with two or more types.

[0081] From the viewpoint of reactivity, 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, even more preferably 100 to 1,000, even more preferably 120 to 1,000, and even more preferably 140 to 300. It should be noted that "epoxy equivalent" is the number of grams (g / eq) of resin containing 1 gram equivalent of epoxy groups, determined according to the method specified in JIS K 7236. Furthermore, the weight-average molecular weight of the epoxy resin is preferably 5,000 or less.

[0082] Epoxy resin can be either liquid or solid, or both liquid and solid epoxy resins can be used. Here, "liquid" and "solid" refer to the state of epoxy resin at room temperature (25°C) and normal pressure (1 atmosphere).

[0083] There is no particular limitation on the amount of epoxy resin. When using epoxy resin, its 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 the total amount of the resin composition layer (i.e., relative to the total amount of non-volatile components of the resin composition).

[0084] From the viewpoint of the moisture barrier properties of the sealing sheet of the present invention, the resin composition layer preferably includes semi-calcined hydrotalcite. Only one type of semi-calcined hydrotalcite may be used, or two or more types may be used.

[0085] Hydrotalcite can be classified into uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite.

[0086] Uncalcined hydrotalcite, for example, is natural hydrotalcite (Mg6Al2(OH)). 16Metal hydroxides with a layered crystal structure, represented by CO3·4H2O, such as those consisting of layers [Mg] forming the basic framework. 1-X Al X (OH)2] X+ and the intermediate layer [(CO3)] X / 2 ·mH2O] X- Composition. The uncalcined hydrotalcite in this invention is a concept encompassing hydrotalcite-like compounds such as synthetic hydrotalcite. Examples of hydrotalcite-like compounds include compounds represented by formulas (I) and (II) below.

[0087] [M 2+ 1-x M 3+ x (OH)2] x+ ·[(A n- ) x / n ·mH2O] x- (I)

[0088] (where M is in the formula) 2+ Indicates Mg 2+ Zn 2+ Metal ions with the same divalent valence, M 3+ Indicates Al 3+ Fe 3+ Metal ions with the same trivalent valence, A n- CO3 2- Cl - NO3 - (Anions with the same valence n, 0 < x < 1, 0 ≤ m < 1, n is a positive number)

[0089] In formula (I), M 2+ Mg is preferred 2+ M 3+ Al is preferred 3+ A n- CO3 is preferred 2- .

[0090] M 2+ x Al2(OH) 2x+6-nz (A n- ) z ·mH2O (II)

[0091] (where M is in the formula) 2+ Indicates Mg 2+ Zn 2+ Metal ions with the same divalent valence, A n- CO3 2- Cl-, NO3 -For anions with the same n-valence, x is a positive number greater than 2, z is a positive number less than 2, m is a positive number, and n is a positive number.

[0092] In equation (II), M 2+ Mg is preferred 2+ A n- CO3 is preferred 2- .

[0093] Semi-calcined hydrotalcite refers to a metal hydroxide with a layered crystal structure obtained by calcining uncalcined hydrotalcite, resulting in a reduced or absent amount of interlayer water. The term "interlayer water," if used in a compositional description, refers to "H₂O" as recorded in the compositional formulas of the aforementioned uncalcined natural hydrotalcite and hydrotalcite-like compounds.

[0094] On the other hand, calcined hydrotalcite refers to a metal oxide with an amorphous structure obtained by calcining uncalcined or semi-calcined hydrotalcite, in which not only the interlayer water disappears but also the hydroxyl groups disappear due to condensation and dehydration.

[0095] Uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished based on their saturated water absorption rate. Semi-calcined hydrotalcite has a saturated water absorption rate of 1% by mass or more but less than 20% by mass. On the other hand, uncalcined hydrotalcite has a saturated water absorption rate of less than 1% by mass, while calcined hydrotalcite has a saturated water absorption rate of 20% by mass or more.

[0096] In this invention, "saturated water absorption rate" refers to the following mass increase rate, which can be calculated by the following formula (i). The mass increase rate is: 1.5g of uncalcined hydrotalcite, semi-calcined hydrotalcite, or calcined hydrotalcite is weighed using a balance, and after determining the initial mass, it is left to stand for 200 hours at atmospheric pressure in a small environmental test apparatus (ESPEC SH-222) set to 60°C and 90% RH (relative humidity). The mass increase rate of the mass after standing for 200 hours is the mass increase rate relative to the initial mass. The formula (i) is: Saturated water absorption rate (mass%) = 100 × (mass after moisture absorption - initial mass) / initial mass (i).

[0097] The saturated water absorption rate of semi-calcined hydrotalcite is preferably 3% by mass or more and less than 20% by mass, more preferably 5% by mass or more and less than 20% by mass.

[0098] Furthermore, uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished based on the rate of decrease in thermal mass determined by thermogravimetric analysis. Semi-calcined hydrotalcite has a thermal mass decrease rate of less than 15% by mass at 280°C and a thermal mass decrease rate of more than 12% by mass at 380°C. On the other hand, uncalcined hydrotalcite has a thermal mass decrease rate of more than 15% by mass at 280°C, and calcined hydrotalcite has a thermal mass decrease rate of less than 12% by mass at 380°C.

[0099] Thermogravimetric analysis (TGA) can be performed using a Hitachi High-Tech Science TG / DTAEXSTAR 6300. Weigh 5 mg of hydrotalcite into an aluminum sample pan, and perform the analysis in an open, uncovered state under a nitrogen flow rate of 200 mL / min, heating from 30 °C to 550 °C at a rate of 10 °C / min. The rate of decrease in thermal mass can be calculated using the following formula (ii): Rate of decrease in thermal mass (mass%) = 100 × (mass before heating - mass at the specified temperature) / mass before heating (ii).

[0100] Furthermore, uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished based on the peaks and relative intensity ratios determined by powder X-ray diffraction. For semi-calcined hydrotalcite, powder X-ray diffraction shows a split peak or a peak with a shoulder formed by the synthesis of two peaks in the vicinity of 2θ (8–18°). The relative intensity ratio (low-angle diffraction intensity / high-angle diffraction intensity) of the peak or shoulder appearing on the low-angle side is 0.001–1,000 to the peak or shoulder appearing on the high-angle side. On the other hand, uncalcined hydrotalcite has only one peak in the vicinity of 8–18°, or the relative intensity ratio of the peak or shoulder appearing on the low-angle side to the peak or shoulder appearing on the high-angle side is outside the aforementioned range. Calcined hydrotalcite does not exhibit characteristic peaks in the 8°–18° region, but does have a characteristic peak at 43°. For powder X-ray diffraction measurements, a powder X-ray diffractometer (Panalytical, Empyrean) is used, with the cathode... The diffraction was performed under the following conditions: voltage 45V, current 40mA, sampling width 0.0260°, scanning speed 0.0657° / s, and the diffraction angle range (2θ) was 5.0131–79.9711°. Peak search was performed using the peak search function of the software provided with the diffraction apparatus, under the following conditions: minimum significance 0.50, minimum peak value 0.01°, maximum peak value 1.00°, baseline width 2.00°, and the method being the minimum value of the second derivative.

[0101] The preferred BET specific surface area of ​​semi-calcined hydrotalcite is 1–250 m². 2 / g, more preferably 5-200mg 2 / g. The BET specific surface area of ​​semi-calcined hydrotalcite can be calculated using the BET method, using a specific surface area measuring device (Macsorb HM Model 1210, manufactured by Mounttech), where nitrogen gas is adsorbed onto the sample surface, and the BET multi-point method is used.

[0102] The particle size of the semi-calcined hydrotalcite is preferably 1 to 1,000 nm, more preferably 10 to 800 nm. The particle size of the semi-calcined hydrotalcite is the median particle size of the particle size distribution when the particle size distribution is prepared on a volume basis by laser diffraction scattering particle size distribution determination (JIS Z 8825).

[0103] Semi-calcined hydrotalcite can be surface-treated with a surface treatment agent. Surface treatment agents used include, for example, higher fatty acids, alkylsilanes, and silane coupling agents, with higher fatty acids and alkylsilanes being more suitable. One or more surface treatment agents can be used.

[0104] Examples of higher fatty acids include stearic acid, linoleic acid, myristic acid, and palmitic acid, which have 14 or more carbon atoms, with stearic acid being preferred. One or more of these may be used.

[0105] Examples of alkylsilanes include: methyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, dimethyldimethoxysilane, octyltriethoxysilane, and n-octadecyldimethyl(3-(trimethoxysilyl)propyl)ammonium chloride. One or more of these may be used.

[0106] Examples of silane coupling agents include: epoxy silane coupling agents such as 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 3-epoxypropoxypropyl(dimethoxy)methylsilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; mercapto silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 11-mercaptoundecyltrimethoxysilane; and mercapto silane coupling agents such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, N-phenyl-3-aminopropyltrimethoxysilane, N-methylaminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2- Amino-based silane coupling agents such as (aminoethyl)-3-aminopropyldimethoxymethylsilane; ureo-based silane coupling agents such as 3-ureopropyltriethoxysilane; vinyl-based silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinylmethyldiethoxysilane; styryl-based silane coupling agents such as p-styryltrimethoxysilane; acrylate-based silane coupling agents such as 3-acryloyloxypropyltrimethoxysilane and 3-methacryloyloxypropyltrimethoxysilane; isocyanate-based silane coupling agents such as 3-isocyanate-propyltrimethoxysilane; sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)disulfide and bis(triethoxysilylpropyl)tetrasulfide; phenyltrimethoxysilane, methacryloyloxypropyltrimethoxysilane, imidazole silane, triazine silane, etc. One or more of these can be used.

[0107] Surface treatment of semi-calcined hydrotalcite can be performed, for example, by simultaneously spraying a surface treatment agent onto untreated semi-calcined hydrotalcite at room temperature using a mixer, and stirring for 5 to 60 minutes. Known mixers can be used, such as V-type mixers, ribbon mixers, double cone mixers, Henschel mixers, concrete mixers, ball mills, and cutter mills. Alternatively, surface treatment can be performed by adding the aforementioned higher fatty acids, alkylsilanes, or silane coupling agents while pulverizing the semi-calcined hydrotalcite using a ball mill or similar equipment. The amount of surface treatment agent used varies depending on the type of semi-calcined hydrotalcite or the type of surface treatment agent; however, the preferred amount of surface treatment agent is 1 to 10 parts by weight relative to 100 parts by weight of untreated semi-calcined hydrotalcite. In this invention, surface-treated semi-calcined hydrotalcite is also included in "semi-calcined hydrotalcite".

[0108] There is no particular limitation on the amount of semi-calcined hydrotalcite. From the viewpoint of the moisture barrier properties of the sealing sheet, when using semi-calcined hydrotalcite, its amount relative to the entire resin composition layer (i.e., relative to the entire non-volatile components of the resin composition) is preferably 3 to 50% by mass, more preferably 5 to 45% by mass, and even more preferably 10 to 40% by mass.

[0109] Examples of semi-calcined hydrotalcite include "DHT-4C" (manufactured by Kyowa Chemical Industry Co., Ltd., particle size: 400 nm) and "DHT-4A-2" (manufactured by Kyowa Chemical Industry Co., Ltd., particle size: 400 nm). Examples of calcined hydrotalcite include "KW-2200" (manufactured by Kyowa Chemical Industry Co., Ltd., particle size: 400 nm). Examples of uncalcined hydrotalcite include "DHT-4A" (manufactured by Kyowa Chemical Industry Co., Ltd., particle size: 400 nm) and "STABIACE HT-1, HT-7, HT-P" (manufactured by Sakai Chemical Industry Co., Ltd.).

[0110] The resin composition layer may contain other components different from the olefin resins, epoxy resins, and semi-calcined hydrotalcite mentioned above. There are no limitations on these other components; components known as ingredients in sealing resin compositions may be used. Examples of other components include: curing agents, curing accelerators, resins different from olefin resins and epoxy resins, inorganic fillers different from semi-calcined hydrotalcite, silane coupling agents, etc. Only one of these other components may be used, or two or more may be used.

[0111] When using olefinic resins and / or epoxy resins with epoxy groups, it is preferable to use a curing agent, or a combination of a curing agent and a curing accelerator, to cure them.

[0112] In this invention, the resin composition layer may contain other resins different from olefin resins and epoxy resins. Examples of other resins include tackifying resins and thermoplastic resins different from olefin resins (e.g., phenoxy resins). Like epoxy resins, phenoxy resins may also have epoxy groups. The epoxy equivalent of the phenoxy resin is preferably more than 5,000 and less than 16,000, more preferably more than 10,000 and less than 16,000.

[0113] In this invention, the resin composition layer may contain other inorganic fillers different from semi-calcined hydrotalcite. Examples of other inorganic fillers include: uncalcined hydrotalcite, calcined hydrotalcite, talc, silica, alumina, 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, etc. The amount of other inorganic fillers relative to the total amount of the resin composition layer (i.e., relative to the total amount of non-volatile components of the resin composition) is preferably 0 to 12% by mass, more preferably 0 to 10% by mass, and even more preferably 0 to 8% by mass.

[0114] The thickness of the resin composition layer is preferably 5-75 μm, more preferably 5-50 μm, and even more preferably 5-30 μm.

[0115] The sealing sheet of the present invention can be manufactured, for example, by coating a resin composition varnish onto a first sheet and drying it to form a resin composition layer, and then sequentially stacking a second sheet and a third sheet on the resulting resin composition layer.

[0116] The resin composition varnish can be prepared by mixing the components of the resin composition with an organic solvent using a kneading roller or rotary mixer. The non-volatile component of the resin composition varnish is preferably 20-80% by mass, more preferably 30-70% by mass.

[0117] Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetates such as ethyl acetate, butyl acetate, cellolytic acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellolytic agents and butyl carbitol; aromatics such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and aromatic mixed solvents such as naphtha. Furthermore, commercially available aromatic mixed solvents include, for example, "Swasol" (manufactured by Maruzen Oil Company) and "Ipzole" (manufactured by Idemitsu Kosan Company). Only one organic solvent may be used, or two or more may be used.

[0118] There are no particular limitations on the drying conditions used to form the resin composition layer. For example, the drying temperature is 80–130°C, and the drying time is 3–60 minutes. When the resin composition layer contains epoxy resin, the drying temperature is preferably 80–100°C, and the drying time is preferably 5–90 minutes. When the resin composition layer does not contain epoxy resin but contains olefinic resin, the drying temperature is preferably 80–130°C, and the drying time is preferably 15–60 minutes.

[0119] After forming a resin composition layer on a first sheet, a second sheet and a third sheet are sequentially laminated on the resulting resin composition layer, thereby manufacturing the sealing sheet of the present invention. Known equipment can be used for lamination, such as a roller laminator, a press, or a vacuum pressure laminator.

[0120] The sealing sheet of the present invention is useful as a sheet for sealing electronic devices that are poorly resistant to moisture. The electronic devices are preferably organic EL devices, quantum dot devices, or solar cells.

[0121] Example

[0122] The present invention will be described in more detail below with examples, but the present invention is not limited to the following examples. Of course, it can be implemented with appropriate modifications as appropriate to the context, and these are all included within the technical scope of the present invention.

[0123] <Sheet>

[0124] For the sheets (moisture-proof sheets and polyethylene terephthalate (PET) films with release layers) used in the following examples and comparative examples, the water vapor transmission rate (WVTR) and the like, measured by the methods described later, are recorded in Table 1 below.

[0125] [Table 1]

[0126]

[0127] Table 1 lists sheet A (PET with a barrier layer) as a moisture-proof sheet with a barrier layer (silica vapor-deposited film) on one side of a PET film and a laminated structure of barrier layer / PET film; sheet B (PET1 with an organosilicon release layer) and sheet C (PET2 with an organosilicon release layer) are both sheets with an organosilicon release layer on one side of a PET film and a laminated structure of organosilicon release layer / PET film; sheet E (PET3 with an organosilicon release layer) is a sheet with an organosilicon release layer on both sides of a PET film and a laminated structure of organosilicon release layer / PET film / organosilicon release layer.

[0128] As the first sheet in Examples 1 and 2, and Comparative Examples 1 and 2, the following moisture-proof sheet was used;

[0129] Sheet F: A moisture-proof sheet with a laminated structure of PET film / barrier layer / adhesive layer / PET film / silicone release layer, obtained by bonding the opposite side of the release layer of sheet B (PET1 with silicone release layer) to the barrier layer of sheet A with an adhesive. (Overall thickness of moisture-proof sheet: 50μm; Overall water vapor transmission rate (WVTR) of moisture-proof sheet: 0.06 g / m³) 2 / 24hr)).

[0130] As the second sheet in Comparative Example 1, the following moisture-proof sheet was used;

[0131] Sheet G: A moisture-proof sheet with a laminated structure of PET film / barrier layer / adhesive layer / PET film / silicone release layer, obtained by bonding the opposite side of the release layer of sheet C (PET2 with silicone release layer) to the barrier layer of sheet A with an adhesive. (Overall thickness of moisture-proof sheet: 37μm; Overall water vapor transmission rate (WVTR) of moisture-proof sheet: 0.12 g / m³) 2 / 24hr)).

[0132] In order to manufacture the third sheet in Examples 1 and 2, the following moisture-proof sheet was used;

[0133] Sheet H: A moisture-proof sheet with a laminated structure of PET film / barrier layer / adhesive layer / PET film, obtained by bonding sheet D (PET film) and the barrier layer of sheet A together with an adhesive. (Overall thickness of the moisture-proof sheet: 37μm; Overall water vapor transmission rate (WVTR) of the moisture-proof sheet: 0.12 g / m³) 2 / 24hr)).

[0134] In Examples 1 and 2, and Comparative Examples 1 and 2, sealing sheets were manufactured on the premise that the second sheet was peeled off during the formation of the sealing layer of the electronic device. Furthermore, in Examples 1 and 2, sealing sheets were manufactured on the premise that the third sheet was peeled off before the resin composition layer dried.

[0135] As the third sheet in the sealing sheets of Examples 1 and 2, the following moisture-proof sheets were used respectively;

[0136] Sheet H with adhesive layer A: A moisture-proof sheet with a silicone adhesive layer (5μm) on the side opposite to the PET film with the barrier layer stacked on the sheet H, having a laminated structure of silicone adhesive layer / PET film / barrier layer / adhesive layer / PET film (overall thickness of moisture-proof sheet: 42μm).

[0137] Sheet H with adhesive layer B: A moisture-proof sheet with a butyl rubber adhesive layer (5μm) on the side opposite to the PET film with the barrier layer stacked on the sheet H, having a laminated structure of butyl rubber adhesive layer / PET film / barrier layer / adhesive layer / PET film (overall thickness of moisture-proof sheet: 42μm).

[0138] Sheet H with adhesive layer A is manufactured as follows. First, 100 parts by weight of silicone resin (Shin-Etsu Chemical Industry Co., Ltd. "KR-3704") is dissolved in 50 parts by weight of toluene. Then, 0.5 parts by weight of crosslinking agent (Shin-Etsu Chemical Industry Co., Ltd. "CAT-PL-50T") is added to the resulting solution. The resulting mixture is stirred evenly using a high-speed rotary mixer to obtain a varnish. The varnish is evenly coated onto sheet H using a die coater and heated at 130°C for 1 minute to obtain sheet H with micro-adhesive layer A (overall thickness of the moisture-proof sheet: 42 μm).

[0139] Sheet H with adhesive layer B is manufactured as follows. First, a mixture of 15 parts by weight of butyl rubber (IIR065, manufactured by Japan Butyl Corporation) and 85 parts by weight of toluene is uniformly stirred using a high-speed rotary mixer to obtain a varnish. The varnish is uniformly coated onto sheet H using a die coater, and heated at 130°C for 3 minutes to obtain sheet H with micro-adhesive layer B (overall thickness of the moisture-proof sheet: 42 μm).

[0140] <Preparation of Resin Composition Varnish>

[0141] Manufacturing Example 1: Manufacturing of Olefin Resin Composition Varnish

[0142] In 130 parts by mass of a 60% by mass Swasol solution of a saturated hydrocarbon resin containing a cyclohexane ring (ARKON P125 manufactured by Arakawa Chemical Co., 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 JXTG Energy Co., Ltd.), and commercially available semi-calcined hydrotalcite (BET specific surface area: 15 m²) were dispersed using a three-roll mill. 2 A mixture was obtained by mixing 100 parts by weight of a 20% by weight solution of glycidyl methacrylate-modified polypropylene-polybutene copolymer ("T-YP341" manufactured by Starlight PMC), 0.5 parts by weight of curing accelerator (2,4,6-tris(dimethylaminomethyl)phenol), and 16 parts by weight of toluene. The mixture was then uniformly dispersed using a high-speed rotary mixer to obtain an olefin-based resin composition varnish.

[0143] <Water absorption rate of hydrotalcite>

[0144] Weigh 1.5 g of the hydrotalcite used in the examples and comparative examples using a balance and determine the initial mass. After standing for 200 hours in a small environmental test chamber (ESPEC SH-222) set to 60°C and 90% RH (relative humidity) at atmospheric pressure, determine the mass after moisture absorption and calculate the saturated water absorption rate using the above formula (i). The results are shown in Table 2.

[0145] <Reduction in thermal weight of hydrotalcite>

[0146] Thermogravimetric analysis (TGA) of the hydrotalcite used in the examples and comparative examples was performed using a Hitachi High-Tech Science TG / DTA EXSTAR6300. 10 mg of hydrotalcite was weighed into an aluminum sample pan, and the pan was heated from 30 °C to 550 °C at a rate of 10 °C / min under an atmosphere of nitrogen flow rate of 200 mL / min, without a lid. The rate of decrease in thermogravimetric analysis at 280 °C and 380 °C was calculated using Equation (ii) above. The results are shown in Table 2.

[0147] <Powder X-ray Diffraction>

[0148] The powder X-ray diffraction measurement was performed using a powder X-ray diffraction apparatus (Panalytical, Empyrean), with the cathode being... The diffraction was performed under the following conditions: voltage 45V, current 40mA, sampling width 0.0260°, scanning speed 0.0657° / s, and a diffraction angle range (2θ) of 5.0131–79.9711°. Peak search was performed using the peak search function of the software attached to the diffraction apparatus, under the following conditions: minimum significance 0.50, minimum peak tip 0.01°, maximum peak tip 1.00°, peak baseline width 2.00°, and the method being the minimum value of the second derivative. Two split peaks appearing in the range of 2θ of 8–18°, or peaks with shoulders due to the synthesis of two peaks, were detected. 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) were measured, and the relative intensity ratio (= low-angle side diffraction intensity / high-angle side diffraction intensity) was calculated. The results are shown in Table 2.

[0149] [Table 2]

[0150]

[0151] The results of saturated water absorption rate, thermal weight loss rate and powder X-ray diffraction confirmed that the hydrotalcite used in the examples and comparative examples was "semi-calcined hydrotalcite".

[0152] <Manufacturing of Sealing Sheets>

[0153] Example 1

[0154] Sheet F is used as the first sheet, sheet C is used as the second sheet, and sheet H with adhesive layer A is used as the third sheet.

[0155] The olefin resin composition varnish obtained in Manufacturing Example 1 was uniformly coated onto the silicone release layer of the first sheet (sheet F) using an orifice-type coating machine, and heated at 130°C for 60 minutes to obtain a laminate 1 having a laminate structure of the first sheet (=PET film / barrier layer / adhesive layer / PET film / silicone release layer) / resin composition layer (resin composition layer thickness: 20 μm).

[0156] Next, an adhesive layer of a third sheet (sheet H with adhesive layer A) is bonded to the PET film of the second sheet (sheet C) to prepare a laminated product 2 with a laminated structure of the second sheet (= silicone release layer / PET film) / the third sheet (= silicone adhesive layer / PET film / barrier layer / adhesive layer / PET film).

[0157] A sealing sheet with a laminated structure having a first sheet (barrier layer / PET film / adhesive layer / PET film / silicone release layer), a second sheet (silicone release layer / PET film), and a third sheet (silicone adhesive layer / PET film / barrier layer / adhesive layer / PET film) is manufactured by bonding the resin composition layer of the obtained laminate 1 to the silicone release layer of the obtained laminate 2 in contact with it. The sheet is then rolled into a roll. The rolled sealing sheet is slit to a width of 507 mm to obtain a sealing sheet with dimensions of 507 × 336 mm.

[0158] The 90-degree peel strength between the second and third sheets (specifically, the 90-degree peel strength between the second sheet (sheet C) and the third sheet (sheet H with adhesive layer A) was determined by the method described later) and the result was 75 gf / inch.

[0159] The 90-degree peel strength between the resin composition layer and the second sheet (more specifically, the 90-degree peel strength between the resin composition layer and the silicone release layer of the second sheet (sheet C)) was determined by the method described later, and the result was 80 gf / inch.

[0160] Example 2

[0161] The third sheet is "sheet H with adhesive layer B", and the second sheet is sheet E. Otherwise, the sealing sheet is manufactured in the same manner as in Example 1.

[0162] The 90-degree peel strength between the second and third sheets (specifically, the 90-degree peel strength between the silicone release layer of the second sheet (sheet E) and the adhesive layer B of the third sheet (sheet H with adhesive layer B) was determined by the method described later, and the result was 30 gf / inch.

[0163] The 90-degree peel strength between the resin composition layer and the second sheet (more specifically, the 90-degree peel strength between the resin composition layer and the silicone release layer of the second sheet (sheet E)) was determined by the method described later, and the result was 75 gf / inch.

[0164] Comparative Example 1

[0165] Sheet F is used as the first sheet, and sheet G is used as the second sheet.

[0166] The olefin resin composition varnish obtained in Manufacturing Example 1 was uniformly coated onto the silicone release layer of the first sheet (sheet F) using an orifice-type coating machine, and heated at 130°C for 60 minutes to obtain a laminate 1 having a laminate structure of the first sheet (=PET film / barrier layer / adhesive layer / PET film / silicone release layer) / resin composition layer (resin composition layer thickness: 20 μm).

[0167] On the resin composition layer of the obtained laminate 1, a sealing sheet is manufactured by bonding it in contact with the silicone release layer of the second sheet (sheet G) to produce a laminated structure of a first sheet (=PET film / barrier layer / adhesive layer / PET film / silicone release layer) / resin composition layer / second sheet (=silicone release layer / PET film / adhesive layer / barrier layer / PET film), and then rolled into a roll. The rolled sealing sheet is longitudinally cut into sections with a width of 507 mm to obtain a sealing sheet with dimensions of 507 × 336 mm.

[0168] Comparative Example 2

[0169] Sheet C is used as the second sheet, and the sealing sheet is otherwise manufactured in the same manner as in Comparative Example 1.

[0170] Table 3 below describes the first to third sheets used in Examples 1 and 2, as well as Comparative Examples 1 and 2.

[0171] [Table 3]

[0172]

[0173] <Determination Method>

[0174] (1) Determination of water vapor transmission rate (WVTR)

[0175] The water vapor transmission rate of the sheet was determined using an infrared sensing method based on JIS K7129B. Specifically, a water vapor transmission rate measuring device (MOCON PERMATRAN-W 3 / 34) was used to measure the water vapor transmission rate (g / m³) of the sheet in an atmosphere with a temperature of 40°C and a relative humidity of 90%. 2 / 24hr).

[0176] (2) Determination of 90-degree peel strength

[0177] The 90-degree peel strength between the second and third sheets in Examples 1 and 2 was determined as follows. First, the sealing sheets prepared in Examples 1 and 2 were cut into lengths of 25 mm × 140 mm and fixed to the first sheet with double-sided tape on glass epoxy plates cut into lengths of 25 mm × 100 mm. The prepared samples were assembled into a Kyowa Interface Science VPA-H100 tensile testing machine, and the peel strength between the second and third sheets was determined at 90 degrees and a speed of 300 mm / s. In addition, the 90-degree peel strength between the resin composition layer in Examples 1 and 2 and the second sheet was also determined in the same manner.

[0178] (3) Determination of water content

[0179] The moisture content of the resin composition layer of the sealing sheets manufactured in Examples 1 and 2, and Comparative Examples 1 and 2, was measured before and after placement and after drying, as described below.

[0180] (3-1) Moisture content A before placement

[0181] The sealing sheet was cut into 7cm squares within 8 hours of manufacture. The resin composition layer removed from these squares was used as a sample before storage. Its moisture content was determined using a Karl Fischer moisture analyzer (Mitsubishi Chemical Analysis Technology Co., Ltd. "Micro Moisture Analyzer CA-310") with coulometric titration. The moisture content A before storage is shown in Table 4 below.

[0182] The apparatus consists of a glass container and a titration device. The glass container holds a heatable sample, and the titration device contains a reaction solution for titrating the water vaporized during sample heating. The vaporized water is moved from the glass container to the reaction solution side of the titration device by a flow of nitrogen gas at a flow rate of 250 ± 25 ml / min. For the determination, the sample is placed in a glass container under a nitrogen atmosphere (water vapor content < 0.1 ppm (mass standard)), and the amount of vaporized water is titrated at 250°C to calculate the water content of the resin composition layer. It should be noted that the unit "ppm" for water content described below refers to mass standard.

[0183] (3-2) Moisture content B after placement

[0184] Sealing sheets cut to 7 cm squares were placed in an atmosphere of 25°C and 50% RH for 24 hours. The resin composition layer removed from the sealing sheet was used as a sample after placement, and its moisture content was measured in the same manner as above. The moisture content B after placement is shown in Table 4 below.

[0185] Calculate the ratio of the moisture content B after storage to the moisture content A before storage, as measured above (i.e., moisture content B after storage / moisture content A before storage, sometimes referred to as "B / A" below). This ratio is also shown in Table 4 below.

[0186] The sealing sheet was evaluated according to the following criterion 1 in accordance with B / A. The results are also shown in Table 4 below;

[0187] (Benchmark 1)

[0188] 〇 (Good): B / A ratio below 2.0

[0189] × (Bad): B / A is above 2.0.

[0190] (3-3) Moisture content C after drying

[0191] The sealing sheets, cut into 7 cm squares and placed in an atmosphere of 25°C and 50% RH for 24 hours, were heated at 150°C for 30 minutes and dried. For the sealing sheets of Examples 1 and 2, a third sheet was peeled off and dried. For the sealing sheets of Examples 1 and 2, and Comparative Examples 1 and 2, drying was performed without peeling off the second sheet. After drying, the resin composition layer removed from the sealing sheet was used as a dried sample, and its moisture content was measured in the same manner as described above. The moisture content C after drying is shown in Table 4 below.

[0192] Calculate the ratio of the dried moisture content C, as measured above, to the moisture content A before storage (i.e., dried moisture content C / moisture content A before storage, sometimes referred to as "C / A" below). This ratio is also shown in Table 4 below.

[0193] The sealing sheets were evaluated using the following standard 2 based on the dried moisture content C and C / A. The results are also shown in the table below;

[0194] (Benchmark 2)

[0195] 〇 (Good): C / A ratio below 0.5

[0196] △ (Pass): C / A is 0.5 or higher but lower than 0.8

[0197] × (Bad): C / A is above 0.8.

[0198] (4) Determination of Ca surface degradation behavior

[0199] The sealing performance of the dried sealing sheet was evaluated by using a glass substrate with a Ca film instead of an organic EL element in a simulation experiment, and the same method was performed as described in "(2-3) Moisture content C after drying".

[0200] In detail, firstly, Ca is deposited on a glass substrate (thickness: 700 μm, width: 50 mm, height: 50 mm) to form a Ca film (thickness: approximately 300 nm, width: 40 mm, height: 40 mm). The resulting glass substrate has a 2 mm sealing width around the Ca film (i.e., the width of the glass substrate without the Ca film in contact with the sealing sheet).

[0201] Next, after drying the sealing sheet, the first sheet is peeled off, and the sealing sheet is laminated with the PET-coated AL1N30 manufactured by Toyo Aluminum Co., Ltd., with the resin composition layer of the sealing sheet in contact with it. Then, the second sheet of the sealing sheet is peeled off, and the sealing sheet is laminated with the glass substrate with the resin composition layer in contact with the Ca film, thereby sealing the Ca film and obtaining the laminated product. These laminations are performed using a roller laminator (Fujiplastic Co., Ltd. "LPD2325", roller material: rubber) under conditions of roller temperature of 90°C, roller speed of 360 mm / min, roller pressure of 0.2 MPa, and nitrogen atmosphere.

[0202] The laminated products obtained as described above were placed in an accelerated testing machine (ESPEC's "Small Environmental Testing Machine SH-222") and subjected to an accelerated test for 24 hours at 85°C and 85% RH to evaluate the degradation behavior of the Ca film surface based on the reaction Ca (opaque) + 2H₂O → Ca(OH)₂ (transparent). Specifically, the reflectance D before and after the accelerated test at 850 nm was measured, and the ratio of the reflectance E after the accelerated test to the reflectance D before the accelerated test (i.e., reflectance E after the accelerated test / reflectance D before the accelerated test, sometimes referred to as "E / D") was calculated. The following benchmark 3 was used for evaluation. It should be noted that a higher E / D indicates better sealing performance of the sealing sheet. The results are shown in Table 4 below.

[0203] (Benchmark 3)

[0204] ○ (Good): E / D ratio is above 0.85

[0205] △ (Pass): E / D ratio is 0.50 or higher and lower than 0.85

[0206] × (Bad): E / D ratio is below 0.50.

[0207] [Table 4]

[0208]

[0209] As shown in Table 4, the sealing sheet of Comparative Example 1, which has a laminated structure of moisture-proof sheet (first sheet) / resin composition layer / moisture-proof sheet (second sheet), can suppress the increase in moisture content in the resin composition layer during storage, but cannot effectively dry the resin composition layer. Furthermore, the sealing sheet of Comparative Example 2, which has a laminated structure of moisture-proof sheet (first sheet) / resin composition layer / non-moisture-proof sheet (second sheet), cannot suppress the increase in moisture content in the resin composition layer during storage, and the moisture content after drying is also high. On the other hand, the sealing sheets of Examples 1 and 2, which have a laminated structure of moisture-proof sheet (first sheet) / resin composition layer / non-moisture-proof sheet (second sheet) / peelable moisture-proof sheet (third sheet), can suppress the increase in moisture content in the resin composition layer during storage, and by peeling off the third sheet for drying, they can suppress contamination of the resin composition layer and effectively dry the resin composition layer.

[0210] Industrial availability

[0211] The sealing sheet of the present invention is useful in sealing electronic devices that are not very resistant to moisture.

[0212] This application is based on Japanese Patent Application No. 2019-205828, which was filed in Japan and whose contents are fully contained in this application specification.

Claims

1. A sealing sheet having a laminated structure, said laminated structure sequentially comprising a first sheet, a resin composition layer, a second sheet, and a third sheet. in, The water vapor transmission rates of the first and third sheets are each independently 5 g / m². 2 ( / 24hr) or less, The water vapor transmission rate of the second sheet is 10 (g / m²). 2 / 24hr) or more, The second sheet is a sheet having a laminated structure comprising a release layer and a substrate, wherein the release layer is in contact with a resin composition layer, and the substrate is a plastic film. Furthermore, the third sheet can be peeled off.

2. The sealing sheet according to claim 1, wherein, The water vapor transmission rate of the first sheet is less than 0.01 (g / m²). 2 / 24hr).

3. The sealing sheet according to claim 2, wherein, The water vapor transmission rate of the first sheet is 0.005 (g / m²). 2 ( / 24hr) or less.

4. The sealing sheet according to claim 1, wherein, The water vapor transmission rate of the second sheet is 10 (g / m²). 2 (24hr) or more and 20000 (g / m) 2 ( / 24hr) or less.

5. The sealing sheet according to claim 4, wherein, The water vapor transmission rate of the second sheet is 15 (g / m²). 2 (24hr) or more and 15000 (g / m³) 2 ( / 24hr) or less.

6. The sealing sheet according to claim 1, wherein, The water vapor transmission rate of the third sheet is 0.01 (g / m²). 2 ( / 24hr) or more and 1 (g / m 2 ( / 24hr) or less.

7. The sealing sheet according to claim 6, wherein, The water vapor transmission rate of the third sheet is 0.05 (g / m²). 2 ( / 24hr) or more and 0.8 (g / m 2 ( / 24hr) or less.

8. The sealing sheet according to claim 1, wherein, The 90-degree peel strength between the second and third sheets is above 0.1 gf / inch and below 250 gf / inch.

9. The sealing sheet according to claim 8, wherein, The 90-degree peel strength between the second and third sheets is above 0.2 gf / inch and below 200 gf / inch.

10. The sealing sheet according to claim 1, wherein, The third sheet is a sheet with an adhesive layer, and the adhesive layer is in contact with the second sheet.

11. The sealing sheet according to claim 1, wherein, The first sheet is a sheet having a release layer, and the release layer is in contact with the resin composition layer.

12. The sealing sheet according to claim 1, wherein, The resin composition layer contains semi-calcined hydrotalcite.

13. The sealing sheet according to claim 12, wherein, The content of semi-calcined hydrotalcite is 3-50% by mass relative to the overall resin composition layer.

14. The sealing sheet according to claim 13, wherein, The content of semi-calcined hydrotalcite is 5-45% by mass relative to the overall resin composition layer.

15. The sealing sheet according to claim 1, wherein it is a sheet used for sealing electronic devices.

16. The sealing sheet according to claim 15, wherein, The electronic devices are organic EL devices, quantum dot devices, or solar cells.

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