Sealing sheet

Abstract

To provide a sealing sheet capable of forming a sealing layer excellent in water vapor intrusion barrier properties in sealing an electronic device or the like.SOLUTION: The sealing sheet has a laminated structure including a support and a sealing layer. The sealing layer comprises a first moisture-absorbing layer and a second moisture-absorbing layer. The first moisture-absorbing layer contains (A) an olefinic polymer and (B) semi-calcined hydrotalcite. The second moisture-absorbing layer contains (C) an olefinic polymer and (D) calcium oxide.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a sealing sheet useful for sealing electronic devices and the like.

Background Art

[0002] In order to protect electronic devices such as organic EL (Electroluminescence) devices and solar cells from moisture, the electronic devices are sealed using a sealing layer formed from a sealing composition or a sealing sheet. As such a composition or sheet, for example, Patent Document 1 discloses a sealing resin composition containing (A) a polyolefin-based resin and (B) a metal hydroxide selected from the group consisting of hydrotalcite and semi-calcined hydrotalcite, and a sealing sheet formed therefrom. However, hydrotalcite reversibly absorbs and releases moisture. Therefore, in a sealing sheet using hydrotalcite, the moisture absorbed by hydrotalcite during its manufacturing process or distribution process may be released in the sealing layer of an electronic device formed using the sheet, leading to deterioration of the electronic device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a sealing sheet capable of forming a sealing layer excellent in water vapor barrier properties in sealing electronic devices and the like.

Means for Solving the Problems

[0005] The present invention capable of achieving the above object is as follows. [1] A sealing sheet having a laminated structure including a support and a sealing layer, wherein the sealing layer is composed of a first moisture-absorbing layer and a second moisture-absorbing layer, the first moisture-absorbing layer contains the following components (A) and (B): (A) an olefin polymer, and (B) semi-calcined hydrotalcite and the second moisture-absorbing layer contains the following components (C) and (D): (C) an olefin polymer, and (D) calcium oxide A sealing sheet. [2] The sealing sheet according to [1] above, wherein the component (C) in the second moisture-absorbing layer contains an olefin polymer having an acid anhydride group and / or a carboxy group, and the median diameter of the component (D) in the second moisture-absorbing layer is 1 to 300 nm. [3] The sealing sheet according to [2] above, wherein the olefin polymer having an acid anhydride group and / or a carboxy group contained in the component (C) in the second moisture-absorbing layer is an olefin polymer having an acid anhydride group. [4] The sealing sheet according to [2] or [3] above, wherein the component (C) in the second moisture-absorbing layer contains an olefin polymer having an epoxy group. [5] The sealing sheet according to [4] above, wherein the olefin polymer having an acid anhydride group and / or a carboxy group contained in the component (C) in the second moisture-absorbing layer and the olefin polymer having an epoxy group form a crosslinked structure. [6] The sealing sheet according to any one of [1] to [5] above, wherein the first moisture-absorbing layer is in direct contact with the second moisture-absorbing layer. [7] The sealing sheet according to any one of [1] to [6] above, wherein the content of the component (B) is 10 to 80% by mass based on the entire first moisture-absorbing layer. [8] The sealing sheet according to any one of [1] to [7] above, wherein the content of the component (D) is 10 to 80% by mass based on the entire second moisture-absorbing layer. [9] The sealing sheet according to any one of [1] to [8] above, wherein the component (A) in the first moisture-absorbing layer includes an olefin polymer having an acid anhydride group and / or a carboxyl group, and an olefin polymer having an epoxy group.

[10] The sealing sheet according to [9] above, wherein the olefin polymer having an acid anhydride group and / or a carboxyl group contained in the component (A) in the first moisture-absorbing layer is an olefin polymer having an acid anhydride group.

[11] The sealing sheet according to [9] or

[10] above, wherein the olefin polymer having an acid anhydride group and / or a carboxyl group contained in the component (A) in the first moisture-absorbing layer and the olefin polymer having an epoxy group form a crosslinked structure.

[12] The sealing sheet according to any one of [1] to

[11] above, wherein one or both of the component (A) in the first moisture-absorbing layer and the component (C) in the second moisture-absorbing layer contain a liquid olefin polymer.

[13] The sealing sheet according to any one of [1] to

[12] above, wherein one or both of the first and second moisture-absorbing layers contain a tackifier.

[14] The sealing sheet according to any one of [1] to

[13] above, wherein the thickness of the sealing layer is 3 to 200 μm.

[15] The sealing sheet according to any one of [1] to

[14] above, wherein the ratio of the thickness of the second moisture-absorbing layer to the thickness of the first moisture-absorbing layer (thickness of the second moisture-absorbing layer / thickness of the first moisture-absorbing layer) is 0.05 to 2.0.

[16] The sealing sheet according to any one of [1] to

[15] above, wherein the haze of the sealing layer is less than 60%.

[17] An electronic device including a sealing layer formed from the sealing sheet according to any one of [1] to

[16] above. [Effect of the Invention]

[0006] According to the present invention, it is possible to obtain a sealing sheet capable of forming a sealing layer excellent in water vapor intrusion barrier properties in the sealing of electronic devices and the like. [Embodiments for Carrying Out the Invention]

[0007] Sealing sheet The sealing sheet of the present invention has a laminated structure including a support and a sealing layer, the sealing layer is composed of a first moisture-absorbing layer and a second moisture-absorbing layer, the first moisture-absorbing layer contains the following components (A) and (B): (A) an olefin-based polymer, and (B) semi-calcined hydrotalcite and, the second moisture-absorbing layer contains the following components (C) and (D): (C) an olefin-based polymer, and (D) calcium oxide and is characterized by this.

[0008] Since the refractive indices of the olefin-based polymer ((A) component) and the semi-calcined hydrotalcite ((B) component) are close to each other, the first moisture-absorbing layer containing these is a layer excellent in transparency and also has a water vapor intrusion barrier property. The second moisture-absorbing layer is a layer excellent in water vapor intrusion barrier property because it contains (D) calcium oxide. Furthermore, since the water taken in by the semi-calcined hydrotalcite ((B) component) in the first moisture-absorbing layer is captured by the calcium oxide ((D) component) in the second moisture-absorbing layer, problems caused by this taken-in water can be suppressed.

[0009] In order to capture the water taken in by the semi-calcined hydrotalcite ((B) component) in the first moisture-absorbing layer with the calcium oxide ((D) component) in the second moisture-absorbing layer, it is preferable that the first moisture-absorbing layer is in direct contact with the second moisture-absorbing layer.

[0010] The sealing sheet of the present invention has a laminated structure including a support and a sealing layer, and the sealing layer is composed of a first moisture-absorbing layer and a second moisture-absorbing layer. There is no particular limitation on the lamination order of the first moisture-absorbing layer and the second moisture-absorbing layer. The sealing sheet of the present invention may have a laminated structure including the support, the first moisture-absorbing layer, and the second moisture-absorbing layer in this order, or may have a laminated structure including the support, the second moisture-absorbing layer, and the first moisture-absorbing layer in this order. The sealing sheet of the present invention preferably has a laminated structure including the support, the first moisture-absorbing layer, and the second moisture-absorbing layer in this order.

[0011] The sealing sheet of the present invention may have a protective sheet. That is, the sealing sheet of the present invention may have a laminated structure including the support, the sealing layer (i.e., "the first moisture-absorbing layer, the second moisture-absorbing layer" or "the second moisture-absorbing layer, the first moisture-absorbing layer"), and the protective sheet in this order.

[0012] In the sealing sheet of the present invention, other layers (for example, an adhesive layer, a release layer) may be present between the support and the sealing layer and between the sealing layer and the protective sheet.

[0013] From the viewpoint of achieving both sealing properties and adhesion, the thickness of the sealing layer is preferably 3 to 200 μm, more preferably 3 to 150 μm, and even more preferably 3 to 100 μm. The ratio of the thickness of the second moisture-absorbing layer to the thickness of the first moisture-absorbing layer (thickness of the second moisture-absorbing layer / thickness of the first moisture-absorbing layer) is preferably 0.05 to 2.0, more preferably 0.05 to 1.5, and even more preferably 0.05 to 1.0 from the viewpoint of the balance between water vapor intrusion barrier properties and transparency.

[0014] The thicknesses of the support and the protective sheet are not particularly limited, but from the viewpoint of the handleability of the sealing sheet, etc., they are preferably 10 to 150 μm and more preferably 20 to 100 μm, respectively. When the support and the protective sheet are laminated films, the above thickness is the thickness of the laminated film.

[0015] The haze of the sealing layer is preferably less than 60%, more preferably 40% or less, and still more preferably 20% or less. There is no particular limitation on the lower limit of the haze of the sealing layer, but the haze of the sealing layer is, for example, 0% or more. This haze can be measured in accordance with JIS K 7136. Specifically, this haze can be measured by the method described in the Examples section below, using glass as a reference and D65 light.

[0016] Examples of the support and the protective sheet include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; cycloolefin polymers; polyesters such as polyethylene terephthalate (hereinafter sometimes referred to as "PET") and polyethylene naphthalate; polycarbonate; plastic films such as polyimide. Both the support and the protective sheet may be single-layer films or laminated films.

[0017] As the support and the protective sheet, for example, a low moisture permeability film having a barrier layer, or a laminated film of a low moisture permeability film having a barrier layer and another film can be used. Examples of the barrier layer include inorganic films such as a silica vapor deposition film, a silicon nitride film, and a silicon oxide film. The barrier layer may be composed of a plurality of layers of a plurality of inorganic films (for example, a silica vapor deposition film). Further, the barrier layer may be composed of an organic substance and an inorganic substance, or may be a composite multilayer of an organic layer and an inorganic film.

[0018] In the protective sheet, it is preferable that the surface in contact with the sealing layer is subjected to a release treatment. On the other hand, the support may or may not be subjected to a release treatment. Examples of the release treatment include release treatment with a release agent such as a silicone resin-based release agent, an alkyd resin-based release agent, and a fluororesin-based release agent.

[0019] Hereinafter, the components constituting the first moisture absorption layer and the second moisture absorption layer will be described in order. Unless otherwise specified in this specification, each component may be used alone or in combination of two or more.

[0020] <Olefin polymer> The component (A) in the first moisture-absorbing layer and the component (C) in the second moisture-absorbing layer are each an olefin polymer. The olefin polymers in the first and second moisture-absorbing layers may be the same or different from each other. In this specification, the "olefin polymer" means a polymer in which the structural unit derived from an olefin (hereinafter sometimes abbreviated as "olefin unit") is the main structural unit (that is, the amount of the olefin unit is the largest among all the structural units). Hereinafter, the "structural unit derived from butene" or the like, which is an olefin unit, may be abbreviated as "butene unit" or the like.

[0021] The olefin polymer may be an olefin resin (for example, propylene-butene copolymer) or an olefin rubber (for example, butyl rubber, that is, isobutene-isoprene copolymer). In this specification, the "olefin resin" means an olefin polymer that cannot form a rubber elastomer by crosslinking, and the "olefin rubber" means an olefin polymer that can form a rubber elastomer by crosslinking.

[0022] As the olefin, a monoolefin having one olefinic carbon-carbon double bond and / or a diolefin having two olefinic carbon-carbon double bonds is preferable. Examples of the monoolefin include α-olefins such as ethylene, propylene, 1-butene, isobutene (isobutylene), 1-pentene, 1-hexene, 1-heptene, and 1-octene. Examples of the diolefin include 1,3-butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethylbutadiene.

[0023] The olefin polymer may be a homopolymer or a copolymer. The copolymer may be a random copolymer or a block copolymer. Further, the olefin polymer may be a copolymer of an olefin and a monomer other than an olefin. Examples of the olefin copolymer include an ethylene-non-conjugated diene copolymer, an ethylene-propylene copolymer, an ethylene-propylene-non-conjugated diene copolymer, an ethylene-butene copolymer, an ethylene-propylene-butene copolymer, a propylene-butene copolymer, a propylene-butene-non-conjugated diene copolymer, an isobutene-isoprene copolymer, a styrene-isobutene copolymer, a styrene-isobutene-styrene copolymer, and the like.

[0024] (Olefin polymer having an acid anhydride group and / or a carboxy group) It is preferable that one or both of the component (A) in the first moisture-absorbing layer and the component (C) in the second moisture-absorbing layer contain an olefin polymer having an acid anhydride group (i.e., a carbonyloxycarbonyl group (-CO-O-CO-)) and / or a carboxy group, and it is more preferable that both of them contain the polymer. The polymer is preferably an olefin polymer having an acid anhydride group. Note that the description and examples of "olefin" and "olefin polymer" in the olefin polymer having an acid anhydride group and / or a carboxy group are the same as those of the above-described olefin polymer.

[0025] When both the component (A) in the first moisture-absorbing layer and the component (C) in the second moisture-absorbing layer contain an olefin polymer having an acid anhydride group and / or a carboxy group, the polymers may be the same or different from each other.

[0026] The (A) component in the first moisture-absorbing layer preferably contains an olefin polymer having the above-mentioned acid anhydride group and / or carboxy group, and an olefin polymer having an epoxy group described below, and these form a crosslinked structure. By forming such a crosslinked structure, a first moisture-absorbing layer excellent in strength can be obtained. In addition, the mode in which the olefin polymer forms a crosslinked structure is also within the scope of the present invention.

[0027] The (C) component in the second moisture-absorbing layer preferably contains an olefin polymer having the above-mentioned acid anhydride group and / or carboxy group, and an olefin polymer having an epoxy group described below, and these form a crosslinked structure. By forming such a crosslinked structure, a second moisture-absorbing layer excellent in strength can be obtained. In addition, the mode in which the olefin polymer forms a crosslinked structure is also within the scope of the present invention.

[0028] The (C) component in the second moisture-absorbing layer contains an olefin polymer having an acid anhydride group and / or carboxy group, and it is particularly preferable that the median diameter of the (D) component (calcium oxide) in the second moisture-absorbing layer is 1 to 300 nm. By using a fine (D) component, a decrease in the transparency of the second moisture-absorbing layer can be suppressed. In addition, by using an olefin polymer having an acid anhydride group and / or carboxy group, a second moisture-absorbing layer in which fine (D) components are well dispersed can be formed. In this regard, it is presumed that the olefin polymer having an acid anhydride group and / or carboxy group functions as a dispersant for the fine (D) component. However, the present invention is not limited to such a presumption.

[0029] When an olefin polymer having an acid anhydride group is used as the olefin polymer having an acid anhydride group and / or carboxy group, the concentration of the acid anhydride group in the polymer is preferably 0.05 to 10 mmol / g, more preferably 0.10 to 5 mmol / g. The concentration of the acid anhydride group is obtained from the value of the acid value defined as the number of mg of potassium hydroxide required to neutralize the acid present in 1 g of the polymer according to the description of JIS K 2501.

[0030] When an olefin polymer having an acid anhydride group and / or a carboxy group is used as the olefin polymer having a carboxy group, the concentration of the carboxy group in the polymer is preferably 0.05 to 20 mmol / g, more preferably 0.10 to 10 mmol / g. The concentration of the carboxy group is obtained from the acid value defined as the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of the polymer according to the description of JIS K 2501.

[0031] When an olefin polymer having an acid anhydride group and a carboxy group is used as the olefin polymer having an acid anhydride group and / or a carboxy group, the total of the concentration of the acid anhydride group and the concentration of the carboxy group in the polymer is preferably 0.05 to 20 mmol / g, more preferably 0.10 to 10 mmol / g.

[0032] The number average molecular weight of the olefin polymer having an acid anhydride group and / or a carboxy group is preferably 1,000 to 1,000,000, more preferably 1,000 to 750,000, from the viewpoints of the sealing performance and mechanical strength of the sealing layer (the first moisture-absorbing layer and the second moisture-absorbing layer). The number average molecular weight of each component is measured by gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the number average molecular weight by the GPC method can be measured at a column temperature of 40 °C using "LC-9A / RID-6A" manufactured by Shimadzu Corporation as the measuring device, "Shodex K-800P / K-804L / K-804L" manufactured by Showa Denko KK as the column, and toluene or the like as the mobile phase, and can be calculated using the calibration curve of standard polystyrene.

[0033] Olefin polymers having an acid anhydride group and / or a carboxy group can be produced, for example, by (i) graft-modifying an olefin polymer with an unsaturated compound having an acid anhydride group and / or a carboxy group (e.g., maleic anhydride) under radical reaction conditions, or (ii) copolymerizing an unsaturated compound having an acid anhydride group and / or a carboxyl group with an α-olefin.

[0034] As the olefin polymer having an acid anhydride group and / or a carboxy group, for example, polymers available from Toho Chemical Industry Co., Ltd., Seiko PMC Co., Ltd., etc. can be used. Examples of such polymers include "HV-300M" (maleic anhydride-modified liquid polybutene) manufactured by Toho Chemical Industry Co., Ltd., "ER688" (maleic anhydride-modified liquid polybutene) manufactured by Seiko PMC Co., Ltd., "T-YP279" (maleic anhydride-modified propylene-butene random copolymer) manufactured by Seiko PMC Co., Ltd., "T-YP312" (maleic anhydride-modified propylene-butene random copolymer) manufactured by Seiko PMC Co., Ltd., "ER661" (maleic anhydride-modified isobutene-isoprene random copolymer) manufactured by Seiko PMC Co., Ltd., "T-YP430" (maleic anhydride-modified ethylene-methyl methacrylate copolymer) manufactured by Seiko PMC Co., Ltd., "T-YP956" (maleic anhydride-modified ethylene-propylene-butene random copolymer) manufactured by Seiko PMC Co., Ltd., "Daiya Carnal 30M" (copolymer of maleic anhydride and α-olefin) manufactured by Mitsubishi Chemical Corporation, etc.

[0035] In one embodiment of the present invention, the olefin polymer having an acid anhydride group and / or a carboxy group is (i) preferably at least one selected from the group consisting of polybutene having an acid anhydride group and / or a carboxy group, isobutene-isoprene copolymer (i.e., butyl rubber) having an acid anhydride group and / or a carboxy group, propylene-butene copolymer having an acid anhydride group and / or a carboxy group, ethylene-methyl methacrylate copolymer having an acid anhydride group and / or a carboxy group, and ethylene-propylene-butene copolymer having an acid anhydride group and / or a carboxy group, (ii) More preferably, it is at least one selected from the group consisting of polybutene having an acid anhydride group and / or a carboxy group, an isobutene-isoprene copolymer having an acid anhydride group and / or a carboxy group, and a propylene-butene copolymer having an acid anhydride group and / or a carboxy group. (iii) Even more preferably, it is at least one selected from the group consisting of polybutene having an acid anhydride group, an isobutene-isoprene copolymer having an acid anhydride group, and a propylene-butene copolymer having an acid anhydride group. (iv) Particularly preferably, it is polybutene having an acid anhydride group.

[0036] When an olefin polymer having an acid anhydride group and / or a carboxy group is used to form the first moisture-absorbing layer, its content is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less with respect to the entire first moisture-absorbing layer in order to form a crosslinked structure and further improve the water vapor intrusion barrier property and strength.

[0037] When an olefin polymer having an acid anhydride group and / or a carboxy group is used to form the second moisture-absorbing layer, its content is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less with respect to the entire second moisture-absorbing layer in order to form a crosslinked structure, further improve the water vapor intrusion barrier property and strength, and preferably disperse the component (calcium oxide) (D) well in the second moisture-absorbing layer.

[0038] (Olefin polymer having an epoxy group) It is preferable that one or both of the component (A) in the first moisture absorption layer and the component (C) in the second moisture absorption layer contain an olefin-based polymer having an epoxy group, and it is more preferable that both of them contain an olefin-based polymer having an epoxy group. In addition, the descriptions and examples of "olefin" and "olefin-based polymer" in the olefin-based polymer having an epoxy group are the same as those of the above-described olefin-based polymer.

[0039] When both the first and second moisture absorption layers contain an olefin-based polymer having an epoxy group, the polymers may be the same or different from each other.

[0040] The concentration of the epoxy group in the olefin-based polymer having an epoxy group is preferably 0.05 to 10 mmol / g, more preferably 0.10 to 5 mmol / g. The epoxy group concentration is determined from the epoxy equivalent obtained based on JIS K 7236-1995.

[0041] From the viewpoint of improving the sealing performance and mechanical strength of the sealing layer, the number average molecular weight of the olefin-based polymer having an epoxy group is preferably 1,000 to 1,000,000, more preferably 2,000 to 750,000, and still more preferably 2,000 to 500,000.

[0042] The olefin-based polymer having an epoxy group can be obtained, for example, by (i) graft-modifying an olefin-based polymer with an unsaturated compound having an epoxy group (e.g., glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, allyl glycidyl ether) under radical reaction conditions, or (ii) copolymerizing an unsaturated compound having an epoxy group and an α-olefin.

[0043] As the olefin polymer having an epoxy group, for example, polymers available from Sumitomo Chemical Co., Ltd., Seiko PMC Co., Ltd., etc. can be used. Examples of such polymers include "BONDFAST BF-7M" (ethylene-glycidyl methacrylate copolymer) manufactured by Sumitomo Chemical Co., Ltd., "BONDFAST BF-2B" (ethylene-glycidyl methacrylate-vinyl acetate copolymer) manufactured by Sumitomo Chemical Co., Ltd., "BF-7L" (ethylene-glycidyl methacrylate-methyl acrylate copolymer) manufactured by Sumitomo Chemical Co., Ltd., "ER829" (glycidyl methacrylate-modified propylene-butene random copolymer) manufactured by Seiko PMC Co., Ltd., "ER850" (glycidyl methacrylate-modified butyl rubber) manufactured by Seiko PMC Co., Ltd., "ER853" (glycidyl methacrylate-modified propylene-butene random copolymer) manufactured by Seiko PMC Co., Ltd., "ER866" (glycidyl methacrylate-modified butyl rubber) manufactured by Seiko PMC Co., Ltd., "T-YP276" (glycidyl methacrylate-modified propylene-butene random copolymer) manufactured by Seiko PMC Co., Ltd., "T-YP313" (glycidyl methacrylate-modified propylene-butene random copolymer) manufactured by Seiko PMC Co., Ltd., "T-YP431" (glycidyl methacrylate-modified ethylene-methyl methacrylate copolymer) manufactured by Seiko PMC Co., Ltd., and the like.

[0044] The olefin polymer having an epoxy group is (i) preferably at least one selected from the group consisting of an ethylene-glycidyl methacrylate copolymer, an ethylene-glycidyl methacrylate-vinyl acetate copolymer, an ethylene-glycidyl methacrylate-methyl acrylate copolymer, a propylene-butene copolymer having an epoxy group, an isobutene-isoprene copolymer having an epoxy group (i.e., butyl rubber), and an ethylene-methyl methacrylate copolymer having an epoxy group, (ii) more preferably at least one selected from the group consisting of a propylene-butene copolymer having an epoxy group, an isobutene-isoprene copolymer having an epoxy group, and an ethylene-methyl methacrylate copolymer having an epoxy group, (iii) More preferably, it is a propylene-butene copolymer having an epoxy group and / or an isobutene-isoprene copolymer having an epoxy group, (iv) Particularly preferably, it is a propylene-butene copolymer having an epoxy group or an isobutene-isoprene copolymer having an epoxy group.

[0045] When using a propylene-butene copolymer having an epoxy group as the olefin polymer having an epoxy group, the amount of butene units in the copolymer is preferably 1 to 50% by mass, more preferably 2 to 45% by mass, still more preferably 3 to 40% by mass, per 100% by mass of the total of propylene units and butene units. Note that the amount of the butene units is based on the propylene units and butene units excluding the modified portion (for example, the portion derived from glycidyl (meth)acrylate for introducing an epoxy group).

[0046] When using an isobutene-isoprene copolymer having an epoxy group (i.e., butyl rubber) as the olefin polymer having an epoxy group, from the viewpoint of light resistance to yellowing of the moisture absorption layer, etc., the amount of isoprene units in the copolymer is preferably 0.1 to 20% by mass, more preferably 0.3 to 15% by mass, still more preferably 0.5 to 10% by mass, per 100% by mass of the total of isobutene units and isoprene units. Note that the amount of the isoprene units is based on the isobutene units and isoprene units excluding the modified portion (for example, the portion derived from glycidyl (meth)acrylate for introducing an epoxy group).

[0047] When using an olefin polymer having an epoxy group to form the first moisture absorption layer, its content is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, with respect to the entire first moisture absorption layer, in order to form a strong moisture absorption layer.

[0048] When an olefin polymer having an epoxy group is used to form the second moisture-absorbing layer, its content is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, based on the entire second moisture-absorbing layer, in order to form a strong moisture-absorbing layer.

[0049] When an olefin polymer having an epoxy group and an olefin polymer having an acid anhydride group and / or a carboxyl group are used in combination, it is preferable to determine their usage amounts according to the ratio of the functional groups they have. "The amount (mol) of epoxy groups in the olefin polymer having an epoxy group": "The total amount (mol) of acid anhydride groups and carboxyl groups in the olefin polymer having an acid anhydride group and / or a carboxyl group" is preferably 100:50 to 100:1500, more preferably 100:60 to 100:1250, still more preferably 100:70 to 100:1000, and particularly preferably 100:80 to 100:900. For example, when the olefin polymer having an acid anhydride group and / or a carboxyl group has only an acid anhydride group, the "total amount (mol) of acid anhydride groups and carboxyl groups" means the "amount (mol) of acid anhydride groups".

[0050] (Liquid olefin polymer) It is preferable that one or both of the component (A) in the first moisture-absorbing layer and the component (C) in the second moisture-absorbing layer contain a liquid olefin polymer, and it is more preferable that both of them contain a liquid olefin polymer. By using a liquid olefin polymer, good adhesion and flexibility can be imparted to the moisture-absorbing layer. The explanations and examples of "olefin" and "olefin polymer" in the liquid olefin polymer are the same as those of the above-mentioned olefin polymer.

[0051] When both the first and second moisture-absorbing layers contain a liquid olefin polymer, the polymers may be the same or different from each other.

[0052] In the present invention, "liquid" in the "liquid olefin polymer" means that the viscosity at 25°C is 5,000 Pa·s or less. Further, in the present invention, the "viscosity at 25°C" means the viscosity calculated by multiplying the kinematic viscosity at 25°C measured by a dynamic viscoelasticity measuring device by the density. Examples of the dynamic viscoelasticity measuring device include a rheometer manufactured by TA Instruments (trade name: DISCOVERY HR-2).

[0053] In the present invention, a liquid olefin polymer having an acid anhydride group and / or a carboxy group is classified as an olefin polymer having an acid anhydride group and / or a carboxy group. Further, in the present invention, a liquid olefin polymer having an epoxy group is classified as an olefin polymer having an epoxy group. Therefore, the "liquid olefin polymer" in the present invention means a liquid olefin polymer other than a liquid olefin polymer having an acid anhydride group and / or a carboxy group and a liquid olefin polymer having an epoxy group.

[0054] The viscosity at 25°C of the liquid olefin polymer is preferably 5 to 5,000 Pa·s, more preferably 10 to 4,000 Pa·s, and still more preferably 20 to 3,000 Pa·s from the viewpoints of good adhesion and flexibility of the moisture absorption layer.

[0055] The number average molecular weight of the liquid polyolefin polymer is preferably 100 to 50,000, more preferably 200 to 30,000, and still more preferably 300 to 20,000 from the viewpoints of good coatability of the varnish for forming the moisture absorption layer.

[0056] Commercially available liquid olefin polymers can be used. Examples of such commercially available products include "HV-300" (liquid polybutene), "HV-1900" (liquid polybutene), "HV-50" (liquid polybutene), "HV-35" (liquid polybutene) manufactured by ENEOS; "950MW" (liquid polybutene), "2400MW" (liquid olefin polymer) manufactured by Kothari; "H-1900" (liquid polybutene), "H-6000" (liquid polybutene), "H-18000" (liquid polybutene) manufactured by INEOS; "200N" (liquid polybutene) manufactured by NOF Corporation; "BI-2000" (hydrogenated polybutadiene), "BI-3000" (hydrogenated polybutadiene), "GI-3000" (hydrogenated polybutadiene) manufactured by Nippon Soda Co., Ltd.; "Lucant LX100" (liquid olefin polymer), "Lucant LX400" (liquid olefin polymer) manufactured by Mitsui Chemicals, Inc.; "Poly bd R-45HT" (butadiene-based liquid rubber), "Poly bd R-15HT" (butadiene-based liquid rubber), "Poly ip" (liquid polyisoprene) manufactured by Idemitsu Showa Shell Co., Ltd.; "B-1000" (liquid polybutadiene), "B-3000" (liquid polybutadiene), "G-3000" (liquid polybutadiene) manufactured by Nippon Soda Co., Ltd.; "LIR-30" (liquid polyisoprene), "LIR-390" (liquid polyisoprene), "LIR-290" (liquid polyisoprene) manufactured by Kuraray Co., Ltd.; "LBR-302" (liquid polybutadiene), "LBR-305" (liquid polybutadiene), "LBR-361" (liquid polybutadiene) manufactured by Kuraray Co., Ltd.; "L-SBR-820" (liquid styrene-butadiene random copolymer) manufactured by Kuraray Co., Ltd.; "Ricon154" (liquid butadiene), "RICON 184" (liquid styrene-butadiene random copolymer) manufactured by CRAY VALLEY, etc.

[0057] The liquid olefin polymer is preferably liquid polybutene and / or hydrogenated polybutadiene, more preferably liquid polybutene.

[0058] When a liquid olefin polymer is used to form the first moisture-absorbing layer, its content is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less, from the viewpoints of good adhesion and flexibility of the moisture-absorbing layer, based on the entire first moisture-absorbing layer.

[0059] When a liquid olefin polymer is used to form the second moisture-absorbing layer, its content is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less, from the viewpoints of good adhesion and flexibility of the moisture-absorbing layer, based on the entire second moisture-absorbing layer.

[0060] (Other olefin polymers) One or both of the component (A) in the first moisture-absorbing layer and the component (C) in the second moisture-absorbing layer may contain a non-liquid olefin polymer (which may be referred to as "other olefin polymer" in this specification) having none of an acid anhydride group, a carboxy group, and an epoxy group. The descriptions and examples of "olefin" and "olefin polymer" in other olefin polymers are the same as those of the above-described olefin polymers.

[0061] When both the first and second moisture-absorbing layers contain other olefin polymers (i.e., non-liquid olefin polymers having none of an acid anhydride group, a carboxy group, and an epoxy group), the polymers may be the same or different from each other.

[0062] In the present invention, "non-liquid" in "non-liquid olefin polymer" means that the viscosity at 25°C exceeds 5,000 Pa·s.

[0063] The number average molecular weight of the other olefin polymer is from 10,000 to 1,000,000, more preferably from 20,000 to 750,000.

[0064] The other olefin polymer is (i) preferably a propylene-butene copolymer and / or an isobutene-isoprene copolymer (i.e., butyl rubber), (ii) more preferably an isobutene-isoprene copolymer.

[0065] When a propylene-butene copolymer is used as the component (A4), the amount of butene units in the copolymer is preferably from 1 to 50% by mass, more preferably from 2 to 45% by mass, still more preferably from 3 to 40% by mass, per 100% by mass of the total of propylene units and butene units.

[0066] When an isobutene-isoprene copolymer (i.e., butyl rubber) is used as the component (A4), from the viewpoint of yellowing resistance of the moisture absorption layer, etc., the amount of isoprene units in the copolymer is preferably from 0.1 to 20% by mass, more preferably from 0.3 to 15% by mass, still more preferably from 0.5 to 10% by mass, per 100% by mass of the total of isobutene units and isoprene units.

[0067] The content of the other olefin polymer is preferably from 0 to 25% by mass, more preferably from 0 to 20% by mass, still more preferably from 0 to 15% by mass, based on the entire first moisture absorption layer. The content of the other olefin polymer is preferably from 0 to 25% by mass, more preferably from 0 to 20% by mass, still more preferably from 0 to 15% by mass, based on the entire second moisture absorption layer.

[0068] <Semi-calcined hydrotalcite> The component (B) in the first moisture absorption layer is semi-calcined hydrotalcite. Hydrotalcite can be classified into uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite.

[0069] The uncalcined hydrotalcite is a metal hydroxide having a layered crystal structure typified by, for example, natural hydrotalcite (Mg6Al2(OH) 16 CO3·4H2O), and consists of, for example, a layer [Mg 1-X Al X (OH)2] X+ as the basic skeleton and an intermediate layer [(CO3) X / 2 ·mH2O] X- . The uncalcined hydrotalcite is a concept including hydrotalcite-like compounds such as synthetic hydrotalcite. Examples of the hydrotalcite-like compounds include those represented by the following formula (I) and the following formula (II).

[0070] [M 2+ 1-x M 3+ x (OH)2] x+ ·[(A n- ) x / n ·mH2O] x- (I) (In the formula, M 2+ represents a divalent metal ion such as Mg 2+ , Zn 2+ , etc., M 3+ represents a trivalent metal ion such as Al 3+ , Fe 3+ , etc., A n- represents an n-valent anion such as CO3 2- , Cl - , NO3 - , etc., 0 < x < 1, 0 ≤ m < 1, and n is a positive number.) In formula (I), M 2+ is preferably Mg 2+ , M 3+ is preferably Al 3+ , and A n- is preferably CO3 2- .

[0071] M 2+ x Al2(OH) 2x+6-nz (A n- ) z ·mH2O (II) (In the formula, M2+ represents divalent metal ions such as Mg 2+ and Zn 2+ etc., A n- represents n-valent anions such as CO3 2- , Cl - , NO3 - etc., x is a positive number of 2 or more, z is a positive number of 2 or less, m is a positive number, and n is a positive number.) In formula (II), M 2+ is preferably Mg 2+ , and A n- is preferably CO3 2- .

[0072] Semi-calcined hydrotalcite refers to a metal hydroxide having a layered crystal structure obtained by calcining uncalcined hydrotalcite, in which the amount of interlayer water has decreased or disappeared. "Interlayer water", when explained using the composition formula, refers to "H2O" described in the composition formulas of the above-mentioned uncalcined natural hydrotalcite and hydrotalcite-like compounds.

[0073] On the other hand, calcined hydrotalcite is obtained by calcining uncalcined hydrotalcite or semi-calcined hydrotalcite, and refers to a metal oxide having an amorphous structure in which not only interlayer water but also hydroxyl groups have disappeared by condensation dehydration.

[0074] Uncalcined hydrotalcite, semi-calcined hydrotalcite and calcined hydrotalcite can be distinguished by their saturated water absorption rates. The saturated water absorption rate of semi-calcined hydrotalcite is 1% by mass or more and less than 20% by mass. On the other hand, the saturated water absorption rate of uncalcined hydrotalcite is less than 1% by mass, and the saturated water absorption rate of calcined hydrotalcite is 20% by mass or more.

[0075] "Saturated water absorption rate" means the mass increase rate with respect to the initial mass when a measurement sample (for example, semi-calcined hydrotalcite) is weighed at 1.5 g with a balance, the initial mass is measured, and then left standing in a small environmental test chamber (SH-222 manufactured by Espec Corporation) set at 60 °C and 90% RH (relative humidity) under atmospheric pressure for 200 hours. The following formula (i): Saturated water absorption rate (mass %) = 100 × (mass after moisture absorption - initial mass) / initial mass (i) It can be determined by the following formula.

[0076] The saturated water absorption rate of the semi - calcined hydrotalcite is preferably 3 mass % or more and less than 20 mass %, more preferably 5 mass % or more and less than 20 mass %.

[0077] Also, the uncalcined hydrotalcite, semi - calcined hydrotalcite and calcined hydrotalcite can be distinguished by the thermogravimetric reduction rate measured by thermogravimetric analysis. The thermogravimetric reduction rate of the semi - calcined hydrotalcite at 280°C is less than 15 mass %, and the thermogravimetric reduction rate at 380°C is 12 mass % or more. On the other hand, the thermogravimetric reduction rate of the uncalcined hydrotalcite at 280°C is 15 mass % or more, and the thermogravimetric reduction rate of the calcined hydrotalcite at 380°C is less than 12 mass %.

[0078] Thermogravimetric analysis can be carried out using TG / DTA EXSTAR6300 manufactured by Hitachi High - Technologies Corporation. Weigh 5 mg of hydrotalcite into an aluminum sample pan, and under the atmosphere of a nitrogen flow rate of 200 mL / min, in an open state without a lid, at a heating rate of 10°C / min from 30°C to 550°C. The thermogravimetric reduction rate can be determined by the following formula (ii): Thermogravimetric reduction rate (mass %) = 100 × (mass before heating - mass when reaching a predetermined temperature) / mass before heating (ii)

[0079] Furthermore, the uncalcined hydrotalcite, semi-calcined hydrotalcite, and calcined hydrotalcite can be distinguished by the peaks and relative intensity ratios measured by powder X-ray diffraction. The semi-calcined hydrotalcite shows a peak split into two around 2θ = 8 - 18° by powder X-ray diffraction, or a peak with a shoulder formed by the combination of two peaks, and the relative intensity ratio of the diffraction intensity of the peak or shoulder appearing on the low-angle side (= low-angle side diffraction intensity) to the diffraction intensity of the peak or shoulder appearing on the high-angle side (= high-angle side diffraction intensity) (low-angle side diffraction intensity / high-angle side diffraction intensity) is 0.001 - 1,000. On the other hand, the uncalcined hydrotalcite has only one peak around 8 - 18°, or the relative intensity ratio of the diffraction intensities of the peak or shoulder on the low-angle side and the peak or shoulder on the high-angle side is outside the above range. The calcined hydrotalcite has no characteristic peak in the region of 8° - 18° and has a characteristic peak at 43°. The powder X-ray diffraction measurement was carried out using a powder X-ray diffractometer (manufactured by PANalytical, Empyrean) under the conditions of anti-cathode CuKα (1.5405 Å), voltage: 45 V, current: 40 mA, sampling width: 0.0260°, scanning speed: 0.0657° / s, and measurement diffraction angle range (2θ): 5.0131 - 79.9711°. The peak search can be carried out using the peak search function of the software attached to the diffractometer under the conditions of "minimum significance: 0.50, minimum peak tip: 0.01°, maximum peak tip: 1.00°, peak base width: 2.00°, method: minimum value of second derivative".

[0080] The BET specific surface area of the semi-calcined hydrotalcite is preferably 1 - 250 m 2 / g, more preferably 5 - 200 m 2 / g. These BET specific surface areas can be calculated using the BET multi-point method by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device (Macsorb HM Model 1210, manufactured by Mountech) according to the BET method.

[0081] The particle size of the semi-calcined hydrotalcite is preferably from 1 to 1,000 nm, more preferably from 10 to 800 nm. These particle sizes are the median diameters of the particle size distribution when the particle size distribution is created on a volume basis by laser diffraction scattering particle size distribution measurement (JIS Z 8825).

[0082] As the semi-calcined hydrotalcite, those surface-treated with a surface treatment agent can be used. Examples of the surface treatment agent used for surface treatment include higher fatty acids, alkyl silanes, silane coupling agents, etc. Among them, higher fatty acids and alkyl silanes are preferred. One or more surface treatment agents can be used.

[0083] Commercially available products can be used as the semi-calcined hydrotalcite. Examples of such commercially available products include "DHT-4C", "DHT-4A-2", etc. manufactured by Kyowa Chemical Industry Co., Ltd.

[0084] From the viewpoint of the water vapor intrusion barrier performance of the sealing layer, the content of the component (B) is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more with respect to the entire first moisture absorption layer. From the viewpoint of the adhesiveness of the first moisture absorption layer, it is preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 70% by mass or less.

[0085] <Calcium Oxide> The component (D) in the second moisture-absorbing layer is calcium oxide. From the viewpoint of the transparency of the second moisture-absorbing layer, the median diameter of the component (D) is preferably 300 nm or less, more preferably 250 nm or less. From the viewpoint of the dispersibility of the component (D), it is preferably 1 nm or more, more preferably 5 nm or more, and still more preferably 10 nm or more. The median diameter of the component (D) is the median diameter in the volume-based particle size distribution (particle size distribution) measured by the dynamic light scattering method (JIS Z 8828) for the particle size of the component (D) and created based on the measurement. The dynamic light scattering method is a method of calculating the particle size and particle size distribution by analyzing the fluctuation corresponding to the velocity of Brownian motion from the scattered light observed when laser light is irradiated on the particles in the dispersion medium by the photon correlation method. Specifically, this median diameter can be measured and calculated as described in the examples.

[0086] (D) From the viewpoint of the water vapor intrusion barrier property of the sealing layer, the content of the component is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more with respect to the entire second moisture-absorbing layer. From the viewpoint of the adhesiveness of the second moisture-absorbing layer, it is preferably 80% by mass or less, more preferably 75% by mass or less, and still more preferably 70% by mass or less.

[0087] When using calcium oxide with a median diameter of 300 nm or less as the component (D), calcium oxide with a median diameter exceeding 300 nm may be pulverized and used, or a commercially available product of calcium oxide with a median diameter of 300 nm or less may be used. Examples of commercially available products of calcium oxide with a median diameter exceeding 300 nm include "QC-X" manufactured by Inoue Lime Industry Co., Ltd., "WAC series" manufactured by Sankyo Flour Milling Co., Ltd., "HAL-G", "HAL-J", "HAL-F", "HAL-O", "HAL-P", etc. manufactured by Yoshizawa Lime Industry Co., Ltd. Examples of commercially available products of calcium oxide with a median diameter of 300 nm or less include "CaO Nano Powder" manufactured by Filgen Co., Ltd.

[0088] <Other components> Either the first or the second moisture-absorbing layer may contain components other than components (A) to (D) (hereinafter sometimes referred to as "other components") as long as the effects of the present invention are not inhibited. Examples of other components include tackifiers, metal complexes, antioxidants, curing agent accelerators, plasticizers, and the like. Any of these may be used alone or in combination of two or more. Hereinafter, tackifiers and the like will be described in order.

[0089] (Tackifier) A tackifier is a component that imparts adhesiveness to the moisture-absorbing layer. Examples of tackifiers include rosin-based resins, terpene resins, modified terpene resins (such as hydrogenated terpene resins, terpene-phenol copolymer resins, aromatic-modified terpene resins), petroleum resins (aliphatic petroleum resins, hydrogenated petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, copolymer petroleum resins), coumarone-indene resins, alkylphenol resins, xylene resins, and the like.

[0090] Commercially available products can be used as the tackifier. Examples of such commercially available products include the following. Examples of rosin-based resins include Pink Crystal ME-H, Pink Crystal ME-D, Pink Crystal ME-G, Pink Crystal KR-85, Pink Crystal KE-311, Pink Crystal KE-359, Pink Crystal D-6011, Pink Crystal PE-590, Pink Crystal KE-604, Pink Crystal PR-580 (all manufactured by Arakawa Chemical Industries, Ltd.), and the like.

[0091] Examples of terpene resins include YS Resin PX1000, YS Resin PX1150, YS Resin PX1150N, YS Resin PX1250, YS Resin TH130, YS Resin TR105, YS Resin LP, YS Resin CP (all manufactured by Yasuhara Chemical Co., Ltd.), and the like.

[0092] Examples of hydrogenated terpene resins include Clearon P, Clearon M, Clearon K series (all manufactured by Yasuhara Chemical Co., Ltd.), and the like.

[0093] Examples of terpene phenol copolymer resins include YS Polyster 2000, Polyster U, Polyster T, Polyster S, Mighty Ace G (all manufactured by Yasuhara Chemical Co., Ltd.), etc.

[0094] Examples of aromatic modified terpene resins include YS Resin TO85, YS Resin TO105, YS Resin TO115, YS Resin TO125 (all manufactured by Yasuhara Chemical Co., Ltd.), etc.

[0095] Examples of hydrogenated petroleum resins include Escorez 5300 series, 5600 series (both manufactured by ExxonMobil); T-REZ OP501, T-REZ PR803, T-REZ HA085, T-REZ HA103, T-REZ HA105, T-REZ HA125 (all hydrogenated dicyclopentadiene-based petroleum resins, manufactured by ENEOS); Quintone 1325, Quintone 1345 (both manufactured by Nippon Zeon Co., Ltd.); Imarve S-100, Imarve S-110, Imarve P-100, Imarve P-125, Imarve P-140 (all hydrogenated dicyclopentadiene-based petroleum resins, manufactured by Idemitsu Kosan Co., Ltd.); Alcon P-90, Alcon P-100, Alcon P-115, Alcon P-125, Alcon P-140, Alcon M-90, Alcon M-100, Alcon M-115, Alcon M-135, TFS13-030 (all manufactured by Arakawa Chemical Industries, Ltd.), etc.

[0096] Examples of aromatic petroleum resins include ENDEX 155 (manufactured by Eastman); Neopolymer L-90, Neopolymer 120, Neopolymer 130, Neopolymer 140, Neopolymer 150, Neopolymer 170S, Neopolymer 160, Neopolymer E-100, Neopolymer E-130, Neopolymer M-1, Neopolymer S, Neopolymer S100, Neopolymer 120S, Neopolymer 130S, Neopolymer EP-140 (all manufactured by ENEOS); Petcol LX, Petcol 120, Petcol 130, Petcol 140 (all manufactured by Tosoh); T-REZ RB093, T-REZ RC100, T-REZ RC115, T-REZ RC093, T-REZ RE100 (all manufactured by ENEOS), etc.

[0097] Examples of copolymer petroleum resins include T-REZ HB103, T-REZ HB125, T-REZ PR801, T-REZ PR802, T-REZ RD104 (all manufactured by ENEOS); Petro Tack 60, Petro Tack 70, Petro Tack 90, Petro Tack 90HS, Petro Tack 90V, Petro Tack 100V (all manufactured by Tosoh); Quintone D100 (manufactured by Nippon Zeon), etc.

[0098] From the viewpoint of the heat resistance of the moisture absorption layer, etc., the softening point of the tackifier is preferably 50 to 200°C, more preferably 90 to 180°C, and even more preferably 100 to 170°C. The softening point is measured by the ring and ball method in accordance with JIS K2207.

[0099] When using a tackifier to form the first moisture absorption layer, its content is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, and even more preferably 5 to 30% by mass with respect to the entire first moisture absorption layer, from the viewpoints of the adhesiveness and sealing property of the first moisture absorption layer. When using a tackifier to form the second moisture absorption layer, its content is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, and even more preferably 5 to 30% by mass with respect to the entire second moisture absorption layer, from the viewpoints of the adhesiveness and sealing property of the second moisture absorption layer.

[0100] (Metal complex) In order to disperse the component (B) better in the first moisture absorption layer, a metal complex in which a bidentate ligand (hereinafter sometimes referred to as "oxygen-bidentate ligand") in which both coordination atoms are oxygen atoms and a monodentate ligand in which the coordination atom is an oxygen atom (hereinafter sometimes referred to as "oxygen-monodentate ligand") are bonded to the central metal may be used. Further, in order to disperse the component (D) better in the second moisture absorption layer, the above metal complex may be used.

[0101] The metal complex is preferably the following formula (1):

[0102] [Chemical formula]

[0103] [In formula (1), M represents a metal with a valence of 2 or more, R1 and R3 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, an aryl group, or an aralkyl group, R2 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, an alkoxycarbonyl group, an aryl group, or an aralkyl group, X represents a monodentate ligand, The solid line between the oxygen atom (O) in [ ] in formula (1) and M represents a covalent bond, The dashed line between the oxygen atom (O) in [ ] in formula (1) and M represents a coordination bond, and m represents 3 or 4, n represents an integer from 0 to 4, and m ≥ n.] It is a metal complex represented by the following (hereinafter sometimes abbreviated as "metal complex (1)"). Only one kind of metal complex (1) may be used, or two or more kinds may be used in combination.

[0104] In the above formula (1), M is preferably a metal of Group 4 of the periodic table or a metal of Group 13 of the periodic table, more preferably aluminum, titanium or zirconium.

[0105] In this specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0106] In this specification, the alkyl group may be either linear or branched. The number of carbon atoms of the alkyl group (excluding the alkyl group in the long-chain alkyl (meth)acrylate) is preferably 1 to 20, more preferably 1 to 10, and particularly preferably 1 to 6. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a 1-ethylpropyl group, a hexyl group, an isohexyl group, a 1,1-dimethylbutyl group, a 2,2-dimethylbutyl group, a 3,3-dimethylbutyl group, a 2-ethylbutyl group, and the like. The alkyl group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, and an amino group which may have a substituent.

[0107] In this specification, the alkenyl group may be either linear or branched. The number of carbon atoms of the alkenyl group is preferably 2 to 20. Examples of the alkenyl group include an ethenyl group (i.e., a vinyl group), a 1-propenyl group, a 2-propenyl group, a 2-methyl-1-propenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a 3-methyl-2-butenyl group, a 1-pentenyl group, a 2-pentenyl group, a 3-pentenyl group, a 4-pentenyl group, a 4-methyl-3-pentenyl group, a 1-hexenyl group, a 3-hexenyl group, a 5-hexenyl group, and the like. The alkenyl group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, and an amino group which may have a substituent.

[0108] In this specification, the alkynyl group may be either linear or branched. The number of carbon atoms in the alkynyl group is preferably from 2 to 10, more preferably from 2 to 6. Examples of the alkynyl group include ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, 1-pentynyl group, 2-pentynyl group, 3-pentynyl group, 4-pentynyl group, 1-hexynyl group, 2-hexynyl group, 3-hexynyl group, 4-hexynyl group, 5-hexynyl group, 4-methyl-2-pentynyl group and the like. The alkynyl group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an amino group which may have a substituent, and the like.

[0109] In this specification, the number of carbon atoms in the aryl group is preferably from 6 to 18, more preferably from 6 to 14. Examples of the aryl group include phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group and the like. The aryl group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an amino group which may have a substituent, and the like.

[0110] In this specification, the number of carbon atoms in the aralkyl group is preferably from 7 to 16. Examples of the aralkyl group include benzyl group, phenethyl group, naphthylmethyl group, phenylpropyl group and the like. The aralkyl group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an amino group which may have a substituent, and the like.

[0111] In this specification, examples of the amino group which may have a substituent include an amino group, a mono- or di-alkylamino group (e.g., methylamino group, dimethylamino group, ethylamino group, diethylamino group, propylamino group, dibutylamino group), a mono- or di-cycloalkylamino group (e.g., cyclopropylamino group, cyclohexylamino group), a mono- or di-arylamino group (e.g., phenylamino group), a mono- or di-aralkylamino group (e.g., benzylamino group, dibenzylamino group), a heterocyclic amino group (e.g., pyridylamino group), and the like.

[0112] In this specification, the description of the alkyl group in the alkoxy group (that is, alkyloxy group) is the same as the description of the above-mentioned alkyl group. The alkoxy group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an amino group which may have a substituent, and the like.

[0113] In this specification, the description of the alkenyl group in the alkenyloxy group is the same as the description of the above-mentioned alkenyl group. The alkenyloxy group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an amino group which may have a substituent, and the like.

[0114] In this specification, the description of the alkyl group in the alkoxycarbonyl group (that is, alkyloxycarbonyl group) is the same as the description of the above-mentioned alkyl group. The alkoxycarbonyl group may have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an amino group which may have a substituent, and the like.

[0115] Examples of the monodentate ligand represented by X in formula (1) include an alkoxide anion (RO - )(in the above formula, R represents an organic group), a carboxylate anion (RCOO - )(in the above formula, R represents an organic group), oxo (O), and the like.

[0116] The alkoxide anion is RO- (In the above formula, R represents an organic group). The organic group R may be either an aliphatic group or an aromatic group. Further, the aliphatic group may be either a saturated aliphatic group or an unsaturated aliphatic group. The number of carbon atoms of the organic group R is preferably 1 to 20, more preferably 6 to 18, and particularly preferably 8 to 14. The alkoxide anion (RO - ) includes, for example, methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, tert-butoxide, pentyloxide, hexyloxide, phenoxide, 4-methylphenoxide, and the like.

[0117] The carboxylate anion is represented by RCOO - (In the above formula, R represents an organic group). The organic group R may be either an aliphatic group or an aromatic group. Further, the aliphatic group may be either a saturated aliphatic group or an unsaturated aliphatic group. The number of carbon atoms of the organic group R is preferably 1 to 20, more preferably 6 to 18, and particularly preferably 8 to 14. The carboxylate anion (RCOO - ) includes, for example, carboxylate anions corresponding to carboxylic acids such as acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, octylic acid, nonanoic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, benzoic acid, and the like.

[0118] In formula (1), the content within [ ] represents a polydentate ligand. Examples of polydentate ligands include acetylacetone, 3-methyl-2,4-pentanedione, acetylacetaldehyde, 2,4-hexanedione, 2,4-heptanedione, 5-methyl-2,4-hexanedione, 5,5-dimethyl-2,4-hexanedione, benzoylacetone, benzoylacetophenone, salicylaldehyde, 1,1,1-trifluoroacetylacetone, 1,1,1,5,5,5-hexafluoroacetylacetone, 3-methoxy-2,4-pentanedione, 3-cyano-2,4-pentanedione, 3-nitro-2,4-pentanedione, 3-chloro-2,4-pentanedione, acetoacetic acid, methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, salicylic acid, methyl salicylate, malonic acid, dimethyl malonate, diethyl malonate, and the like. In the state of coordinating to the central metal, the polydentate ligand has a structure in which one or more protons are removed therefrom.

[0119] Specific examples of the metal complex (1) in which M is aluminum include aluminum diisopropylate monosec-butyrate, aluminum trissec-butyrate, aluminum triisopropylate, aluminum triethylate, aluminum tris(acetylacetonate), aluminum bis(ethylacetoacetate) mono(acetylacetonate), aluminum tris(ethylacetoacetate), aluminum octadecylacetoacetate diisopropylate, aluminum ethylacetoacetate diisopropylate, aluminum ethylacetoacetate din-butyrate, aluminum propylacetoacetate diisopropylate, aluminum n-butylacetoacetate diisopropylate, aluminum tris(ethylacetoacetate), aluminum mono(acetylacetonate) bis(ethylacetoacetate), aluminum tris(acetylacetonate).

[0120] Specific examples of the metal complex (1) in which M is titanium include tetraisopropyl titanate, tetra-n-butyl titanate, tetraoctyl titanate, tetra-tert-butyl titanate, tetrastearyl titanate, titanium tetraacetylacetonate, titanium octylene glycolate (also known as: bis(2-ethylhexyloxy)bis(2-ethyl-3-oxohexyloxy)titanium(IV)), titanium diisopropoxide bis(ethylacetoacetate), allylacetoacetate triisopropoxide, titanium di-n-butoxide bis(2,4-pentanedionate), titanium diisopropoxide bis(tetramethylheptanedionate), titanium diisopropoxide bis(ethylacetoacetate), titanium(IV) tetra(methylphenolate), titanium oxide bis(2,4-pentanedionate), monoisopropoxy titanium triisostearate, diisopropoxy titanium diisostearate.

[0121] Specific examples of the metal complex (1) in which M is zirconium include zirconium tetra-n-propoxide, zirconium tetra-n-butoxide, zirconium tetra(acetylacetonate), zirconium allylacetoacetate triisopropoxide, zirconium di-n-butoxide bis(2,4-pentanedionate), zirconium diisopropoxide bis(2,4-pentanedionate), zirconium diisopropoxide bis(tetramethylheptanedionate), zirconium diisopropoxide bis(ethylacetoacetate), zirconium butoxide(acetylacetate) bis(ethylacetoacetate), zirconium tributoxide monoacetylacetonate, zirconium octylate, zirconium stearate, tri-n-butoxyzirconium monooxylate, tri-n-butoxyzirconium monostearate.

[0122] When a metal complex is used to form the first moisture absorption layer, its content is preferably 0.01 to 3% by mass, more preferably 0.05 to 2.5% by mass, and still more preferably 0.10 to 2% by mass, based on the entire first moisture absorption layer, from the viewpoint of the dispersibility of component (B) in the first moisture absorption layer and the like. When a metal complex is used to form the second moisture absorption layer, its content is preferably 0.01 to 3% by mass, more preferably 0.05 to 2.5% by mass, and still more preferably 0.10 to 2% by mass, based on the entire second moisture absorption layer, from the viewpoint of the dispersibility of component (D) in the second moisture absorption layer and the like.

[0123] (Antioxidant) In the present invention, the antioxidant is not particularly limited, and known ones can be used. When an antioxidant is used to form the first moisture absorption layer, its content is preferably 0.01 to 5% by mass, more preferably 0.05 to 2.5% by mass, and still more preferably 0.10 to 2% by mass, based on the entire first moisture absorption layer. When an antioxidant is used to form the second moisture absorption layer, its content is preferably 0.01 to 5% by mass, more preferably 0.05 to 2.5% by mass, and still more preferably 0.10 to 2% by mass, based on the entire second moisture absorption layer.

[0124] (Curing accelerator) In the present invention, a curing accelerator may be used to promote the crosslinking reaction between the olefin polymer having an acid anhydride group and / or a carboxy group and the olefin polymer having an epoxy group. Examples of the curing accelerator include imidazole compounds, tertiary / quaternary amine compounds, dimethylurea compounds, and organic phosphine compounds.

[0125] Examples of imidazole compounds include 1H-imidazole, 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2-phenyl-4,5-bis(hydroxymethyl)imidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-phenylimidazole, 2-dodecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, etc. Specific examples of imidazole compounds include Curezol 2MZ, 2P4MZ, 2E4MZ, 2E4MZ-CN, C11Z, C11Z-CN, C11Z-CNS, C11Z-A, 2PHZ, 1B2MZ, 1B2PZ, 2PZ, C17Z, 1.2DMZ, 2P4MHZ-PW, 2MZ-A, 2MA-OK (all manufactured by Shikoku Kasei Kogyo Co., Ltd.), etc.

[0126] There is no particular limitation on the tertiary or quaternary amine compounds. For example, quaternary ammonium salts such as tetramethylammonium bromide, tetrabutylammonium bromide, and triethylmethylammonium 2-ethylhexanoate; diazabicyclo compounds such as DBU (1,8-diazabicyclo[5.4.0]undecene-7), DBN (1,5-diazabicyclo[4.3.0]nonene-5), DBU-phenol salt, DBU-octylate, DBU-p-toluenesulfonate, DBU-formate, and DBU-phenol novolak resin salt; tertiary amines such as benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol (TAP) or their salts; dimethylurea compounds such as aromatic dimethylurea and aliphatic dimethylurea; etc.

[0127] Examples of the dimethylurea compound include aromatic dimethylureas such as DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and U-CAT3512T (manufactured by San-Apro Ltd.); and aliphatic dimethylureas such as U-CAT3503N (manufactured by San-Apro Ltd.). Among them, aromatic dimethylureas are preferably used from the viewpoint of curability.

[0128] Examples of the organic phosphine compound include triphenylphosphine, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tri-tert-butylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, triphenylphosphine triphenylborane, etc. Specific examples of the organic phosphine compound include TPP, TPP-MK, TPP-K, TTBuP-K, TPP-SCN, TPP-S (all manufactured by Hokko Chemical Industry Co., Ltd.), etc.

[0129] When a curing accelerator is used to form the first moisture absorption layer, its content is preferably 0.001 to 5% by mass, more preferably 0.001 to 2.5% by mass, and still more preferably 0.001 to 1% by mass based on the entire first moisture absorption layer. When a curing accelerator is used to form the second moisture absorption layer, its content is preferably 0.001 to 5% by mass, more preferably 0.001 to 2.5% by mass, and still more preferably 0.001 to 1% by mass based on the entire second moisture absorption layer.

[0130] (Plasticizer) The moisture absorption layer may further contain a plasticizer. Examples of the plasticizer include mineral oils such as paraffinic process oil, naphthenic process oil, liquid paraffin, and petrolatum; and vegetable oils such as castor oil, cottonseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, and olive oil.

[0131] <Method for manufacturing a sealing sheet> The sealing sheet of the present invention can be manufactured, for example, by mixing the above-described components and an organic solvent to prepare a varnish for forming a first moisture-absorbing layer (hereinafter sometimes abbreviated as "the first varnish") and a varnish for forming a second moisture-absorbing layer (hereinafter sometimes abbreviated as "the second varnish"), applying and drying one of the obtained first and second varnishes on a support to form one of the first or second moisture-absorbing layers, and applying and drying the other of the first and second varnishes on the moisture-absorbing layer to form the other of the first or second moisture-absorbing layers.

[0132] A sealing sheet having a laminated structure including a support, a sealing layer, and a protective sheet in this order can be manufactured, for example, by applying and drying one of the first and second varnishes on one of the support and the protective sheet to form one of the first or second moisture-absorbing layers, applying and drying the other of the first and second varnishes on the moisture-absorbing layer to form the other of the first or second moisture-absorbing layers, and laminating the other of the support and the protective sheet on the formed sealing layer ("the first moisture-absorbing layer / the second moisture-absorbing layer" or "the second moisture-absorbing layer / the first moisture-absorbing layer").

[0133] When using the first and second varnishes having appropriate viscosities, one of the first and second varnishes can be applied to the support or the protective sheet to form a coating film, the other of the first and second varnishes can be applied to the formed coating film to form a two-layer coating film, and these can be dried together to form a sealing layer ("the first moisture-absorbing layer / the second moisture-absorbing layer" or "the second moisture-absorbing layer / the first moisture-absorbing layer").

[0134] Examples of the organic solvents that can be used in the production of varnishes include ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; cellosolves such as cellosolve; carbitols such as butyl carbitol; aromatic hydrocarbons such as toluene and xylene; amides such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and the like. Commercially available organic solvents, such as "Swazol" manufactured by Maruzen Petrochemical Co., Ltd. and "Ipzol" manufactured by Idemitsu Kosan Co., Ltd., may be used. Only one type of organic solvent may be used, or two or more types may be used in combination.

[0135] The drying of the coating film formed by applying the varnish is preferably carried out by heating the coating film. The heating temperature of the coating film is preferably 50 to 200°C, more preferably 80 to 150°C, and the time is preferably 1 to 60 minutes, more preferably 5 to 30 minutes. The heating of the coating film may be carried out under normal pressure or under reduced pressure.

[0136] The coating film obtained by removing the organic solvent may be further aged by heating. The temperature of this heating is preferably 80 to 200°C, more preferably 100 to 150°C, and the time is preferably 10 to 240 minutes, more preferably 30 to 180 minutes. This heating may be carried out under normal pressure or under reduced pressure.

[0137] Hereinafter, a preferred method for producing the sealing sheet of the present invention having a second moisture-absorbing layer containing a fine (D) component having a median diameter of 1 to 300 nm will be described. However, the sheet may be produced by methods other than the following methods.

[0138] The varnish for forming the second moisture absorption layer is preferably produced through a step of pulverizing a mixture containing an olefin polymer having an acid anhydride group and / or a carboxyl group, calcium oxide having a median diameter exceeding 300 nm, and an organic solvent. Although it is also possible to produce the varnish by mixing calcium oxide having a median diameter of 300 nm or less with other components, in such a simple mixing, it is difficult to disperse fine calcium oxide well in the varnish compared to the case of going through the above step. Also, fine calcium oxide has a large surface area, and as a result, its hygroscopicity also increases. To avoid such moisture absorption, the handleability of fine calcium oxide during the production of the varnish is inferior to that of calcium oxide of normal size. Hereinafter, a preferred production method of the sealing sheet of the present invention having a second moisture absorption layer containing a fine (D) component will be described in order.

[0139] First, it is preferable to mix calcium oxide having a median diameter exceeding 300 nm, an olefin polymer having an acid anhydride group and / or a carboxyl group, and an organic solvent to produce a mixture for pulverization treatment. The content of the calcium oxide is preferably 3 to 75% by mass, more preferably 5 to 70% by mass, based on the entire mixture for pulverization treatment. The content of the olefin polymer having an acid anhydride group and / or a carboxyl group is preferably 3 to 40% by mass, more preferably 5 to 35% by mass, based on the entire mixture for pulverization treatment. The content of the organic solvent is preferably 20 to 70% by mass, more preferably 30 to 60% by mass, based on the entire mixture for pulverization treatment.

[0140] As the organic solvent of the mixture for pulverization treatment, the above-mentioned organic solvent can be used. Only one kind of organic solvent may be used, or two or more kinds may be used in combination.

[0141] Optional components, such as a liquid olefin polymer, a tackifier, etc., may be added to the mixture for pulverization treatment. There is no particular limitation on the addition order of each component, and each component may be added sequentially or simultaneously.

[0142] The pulverization treatment can be carried out using a known pulverizer. By the pulverization treatment, calcium oxide is pulverized and dispersed in the mixture. Examples of known pulverizers include wet bead mills. Examples of the material of the beads include zirconia, alumina, glass, steel, etc. The bead diameter is, for example, about 0.03 to 5 mm. The rotation speed of the rotating shaft of the bead mill is, for example, about 10 to 10,000 rpm. The flow rate of the mixture for the pulverization treatment supplied to the pulverization chamber of the bead mill is, for example, about 0.1 to 10,000 kg / hour. In the wet pulverization by a bead mill, in order to suppress the temperature rise of the mixture during the pulverization treatment, it is preferably carried out while cooling with chiller water. The temperature of the chiller water is, for example, about 0 to 40 °C.

[0143] Optional components may be further added and mixed to the mixture after the pulverization treatment. For example, an olefin polymer having an epoxy group, a liquid olefin polymer, a tackifier, etc. may be added and mixed to the mixture after the pulverization treatment. There is no particular limitation on the addition order of each component, and each component may be added sequentially or simultaneously. When the varnish contains an olefin polymer having an epoxy group, in order to prevent the cross-linking reaction from proceeding due to heat during the pulverization treatment, it is preferable to mix the mixture after the pulverization treatment and the olefin polymer having an epoxy group. Except for using the varnish for forming the second moisture-absorbing layer containing the fine (D) component, the sealing sheet of the present invention having the second moisture-absorbing layer containing the fine (D) component can be manufactured by the same method as described above.

[0144] <Electronic device> The present invention also provides an electronic device including a sealing layer formed from the sealing sheet of the present invention. Examples of the electronic device include an organic EL device, a solar cell, a sensor device, a touch panel having a conductive substrate, etc. The electronic device is preferably an electronic device vulnerable to moisture such as an organic EL device or a solar cell.

Examples

[0145] Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and it is also possible to appropriately modify and implement it within the range that conforms to the above and below gists, and all of them are included in the technical scope of the present invention. In addition, "parts" and "%" in the amounts of components and copolymer units mean "parts by mass" and "mass%", respectively, unless otherwise specified.

[0146] <Component> The components used in the production examples are shown below. (1) Olefin polymer having an acid anhydride group and / or a carboxy group "HV-300M" (manufactured by Toho Chemical Industry Co., Ltd., maleic anhydride-modified liquid polybutene, acid anhydride group concentration: 0.77 mmol / g, number average molecular weight: 2,100)

[0147] (2) Olefin polymer having an epoxy group "ER829" (manufactured by Starlight PMC Co., Ltd., glycidyl methacrylate-modified propylene-butene random copolymer, propylene unit / butene unit: 71% / 29%, epoxy group concentration: 0.64 mmol / g, number average molecular weight: 168,000) "ER866" (manufactured by Starlight PMC Co., Ltd., glycidyl methacrylate-modified butyl rubber, epoxy group concentration: 1.63 mmol / g, number average molecular weight: 113,000, isobutene unit / isoprene unit: 98.9% / 1.1%)

[0148] (3) Liquid olefin polymer "HV-1900" (manufactured by ENEOS Co., Ltd., liquid polybutene, number average molecular weight: 2,900, viscosity at 25°C: 460 Pa·s)

[0149] (4) Other olefin polymers "BUTYL065" (manufactured by JSR Corporation, butyl rubber, isobutene unit / isoprene unit: 98.7% / 1.3%)

[0150] (5) Filler (5-1) Semi-calcined hydrotalcite "DHT-4C" (manufactured by Kyowa Chemical Industry Co., Ltd., semi-calcined hydrotalcite, median diameter: 400 nm, BET specific surface area: 15 m 2 / g) (5-2) Calcium oxide Calcium oxide (manufactured by Yoshizawa Lime Industry Co., Ltd., median diameter: 2.1 μm) (5-3) Plate-shaped filler "PDM-5B" (manufactured by Topy Industries, Ltd., synthetic fluorophlogopite, median diameter: 6.0 μm, average aspect ratio: 40

[0151] (6) Tackifier "Alcon P-125" (manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 125°C)

[0152] (7) Metal complex "Purenact Al-M" (manufactured by Ajinomoto Fine-Techno Co., Inc., aluminum octadecenyl acetoacetate diisopropylate)

[0153] (8) Antioxidant "Irganox1010" (manufactured by BASF, hindered phenol-based antioxidant)

[0154] (9) Hardener accelerator 2,4,6-Tris(dimethylaminomethyl)phenol (manufactured by Kayaku Nucreon Co., Ltd., hereinafter abbreviated as "TAP").

[0155] <Production Example 1> Varnishes with the compounding ratios shown in Tables 1-1 and 1-2 below were prepared by the following procedure. The amounts (parts) of each component described in Tables 1-1 and 1-2 indicate the amount of non-volatile matter of each component in the varnish. Also, in Tables 1-1 and 1-2, the median diameter of the calcium oxide contained in the varnish is also described.

[0156] Specifically, maleic anhydride-modified liquid polybutene (Toho Chemical Industry Co., Ltd.'s "HV-300M"), liquid polybutene (ENEOS's "HV-1900"), and semi-calcined hydrotalcite (Kyowa Chemical Industry Co., Ltd.'s "DHT-4C") were mixed with a swazol solution of an adhesion promoter (Arakawa Chemical Industries' "Alcon P-125") (non-volatile content: 60%) using a three-roll mill to obtain a mixture. To the obtained mixture, a swazol solution of a glycidyl methacrylate-modified propylene-butene random copolymer (Starlight PMC's "ER829") (non-volatile content: 15%), a hindered phenol antioxidant (BASF's "Irganox 1010"), a curing accelerator (TAP, manufactured by Kayaku Nurion Co., Ltd.), and toluene were added and mixed using a high-speed rotary mixer to obtain a varnish.

[0157] <Production Examples 2 to 4> A varnish was obtained in the same manner as in Production Example 1, except that the types and amounts of the components used were changed as shown in Table 1-1.

[0158] <Production Example 5> Maleic anhydride-modified liquid polybutene (Toho Chemical Industry Co., Ltd.'s "HV-300M"), liquid polybutene (ENEOS's "HV-1900"), calcium oxide (Yoshizawa Lime Industry Co., Ltd.), and toluene were added to a swazol solution of an adhesion promoter (Arakawa Chemical Industries' "Alcon P-125") (non-volatile content: 60%) to obtain a mixture for grinding treatment (the content of the organic solvent (i.e., the total content of swazol and toluene) in the whole mixture: 24%, the content of maleic anhydride-modified liquid polybutene: 10%, the content of calcium oxide: 48%, the content of the adhesion promoter: 7%, the content of liquid polybutene: 11%).

[0159] The mixture for grinding treatment was put into a wet bead mill (Asizawa Fine Tech Co., Ltd.'s Laboster Mini "LMZ015"), filled with beads (bead diameter: 0.1 mm) so that the effective volume of the grinding chamber was about 60% by volume, and subjected to grinding treatment to obtain a mixture after grinding treatment in which calcium oxide was ground and dispersed.

[0160] A small amount was taken from the mixture after the pulverization treatment, diluted 100-fold with toluene to prepare a measurement sample, and the median diameter of calcium oxide was measured and calculated by the dynamic light scattering method using a nanoparticle size measuring device "NANOTRAC WAVE" manufactured by Microtrac. As a result, the median diameter of calcium oxide was 185 nm.

[0161] A hindered phenol antioxidant ("Irganox 1010" manufactured by BASF) and a curing accelerator (TAP, manufactured by Kayaku Nurion Co., Ltd.) were added to the mixture after the pulverization treatment, and mixed with a high-speed rotary mixer to obtain a varnish.

[0162] <Production Example 6> A varnish was obtained in the same manner as in Production Example 7, except that the amount of calcium oxide used was changed from 300 parts to 120 parts.

[0163] <Production Example 7> A varnish was obtained in the same manner as in Production Example 8, except that the bead diameter used in the wet bead mill was changed from 0.1 mm to 0.2 mm. The median diameter of calcium oxide in the mixture after the pulverization treatment in the production example was measured in the same manner as in Production Example 5, and as a result, the median diameter was 246 nm.

[0164] <Production Example 8> A varnish was obtained in the same manner as in Production Example 1, except that 60 parts of glycidyl methacrylate-modified butyl rubber ("ER866" manufactured by Starlight PMC) was used instead of 60 parts of glycidyl methacrylate-modified propylene-butene random copolymer ("ER829" manufactured by Starlight PMC).

[0165] <Production Examples 9 and 10> A varnish was obtained in the same manner as in Production Example 5, except that the types and amounts of the components used were changed as shown in Table 1-2.

[0166] The varnishes of Production Examples 1, 2, and 8 are varnishes for forming a first moisture-absorbing layer containing component (B) (semi-calcined hydrotalcite), the varnishes of Production Examples 5 to 7, 9, and 10 are varnishes for forming a second moisture-absorbing layer containing component (D) (calcium oxide), and the varnishes of Production Examples 3 and 4 are varnishes for forming other layers containing neither component (B) nor component (D).

[0167] <Example 1> A polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., "SP4020", PET film thickness: 50 μm) with one side treated with a silicone-based release agent and a low moisture permeability polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, "Tech Barrier HX", PET film thickness: 12 μm) were laminated so that the surface of SP4020 not treated with the silicone-based release agent was in contact with Tech Barrier HX to produce a laminated film, which was used as a support for the sealing sheet and a protective sheet. Hereinafter, the "surface of the laminated film treated with the silicone-based release agent" will be referred to as the "release-treated surface".

[0168] The varnish obtained in Production Example 5 was uniformly applied to the release-treated surface of the first laminated film (protective sheet) with a die coater so that the film thickness after drying (i.e., the thickness of the moisture-absorbing layer) was 10 μm to form a coating film. The varnish obtained in Production Example 1 was applied to the formed coating film so that the film thickness after drying (i.e., the thickness of the moisture-absorbing layer) was 40 μm to form a two-layer coating film, and these were heated at 140°C for 30 minutes to form a sealing layer (two-layer moisture-absorbing layer). When the cross-section of the obtained sealing layer was observed, it was confirmed that two-layer moisture-absorbing layers were formed. Hereinafter, the moisture-absorbing layer formed on the protective sheet will be referred to as the "element-side moisture-absorbing layer", and the moisture-absorbing layer formed on the element-side moisture-absorbing layer will be referred to as the "support-side moisture-absorbing layer".

[0169] The second laminated film (support) was laminated on the formed support-side moisture-absorbing layer and heated at 130°C for 60 minutes to obtain a sealing sheet having a laminated structure of "protective sheet / element-side moisture-absorbing layer / support-side moisture-absorbing layer / support". The element-side moisture-absorbing layer and the support-side moisture-absorbing layer constitute the sealing layer of the sealing sheet.

[0170] <Examples 2 to 9> Except that the type of varnish used, the thickness of the moisture-absorbing layer on the element side, and the thickness of the moisture-absorbing layer on the support side were changed as shown in Table 2-1 or Table 2-2, in the same manner as in Example 1, a sealing sheet having a laminated structure of "protective sheet / moisture-absorbing layer on the element side / moisture-absorbing layer on the support side / support" was obtained.

[0171] <Comparative Example 1> The varnish obtained in Production Example 1 was uniformly applied onto the release-treated surface of the first laminated film (protective sheet) with a die coater so that the film thickness after drying (i.e., the thickness of the moisture-absorbing layer) would be 50 μm, and then heated at 140°C for 30 minutes to form a moisture-absorbing layer on the element side.

[0172] A second laminated film (support) was laminated onto the formed moisture-absorbing layer on the element side, and heated at 130°C for 60 minutes to obtain a sealing sheet having a laminated structure of "protective sheet / moisture-absorbing layer on the element side / support".

[0173] <Comparative Examples 2 and 3> Except that the type of varnish used, the thickness of the layer on the element side, and the thickness of the moisture-absorbing layer on the support side were changed as shown in Table 2-3, in the same manner as in Example 1, a sealing sheet having a laminated structure of "protective sheet / layer on the element side / moisture-absorbing layer on the support side / support" was obtained. In Comparative Examples 2 and 3, the layer on the element side was formed using the varnish of Production Example 3 or 4 that does not contain any of component (B) (semi-calcined hydrotalcite) and component (D) (calcium oxide).

[0174] The moisture-absorbing layer formed from the varnish of Production Example 1, 2 or 10 is the first moisture-absorbing layer containing component (B) (semi-calcined hydrotalcite), the moisture-absorbing layer formed from the varnish of Production Examples 5 to 9, 11 or 12 is the second moisture-absorbing layer containing component (D) (calcium oxide), and the layer formed from the varnish of Production Example 3 or 4 is another layer containing neither component (B) nor component (D).

[0175] Regarding the sealing layers of the sealing sheets obtained in the examples and comparative examples, the water vapor barrier property and transparency were evaluated by the following methods.

[0176] <Method for evaluating water vapor barrier property> As a support, a composite film comprising an aluminum foil and a polyethylene terephthalate film ("PET with AL1N30" manufactured by Tokai-Toyo Aluminum Sales Co., Ltd. (thickness of aluminum foil: 30 μm, thickness of PET film: 25 μm)) was prepared.

[0177] Except for using the composite film as a support, in the same manner as in the examples and comparative examples, a test sheet having a laminated structure of "protective sheet (laminated film) / hygroscopic layer on the element side / hygroscopic layer on the support side / support (composite film)" or "protective sheet (laminated film) / hygroscopic layer on the element side / support (composite film)" was obtained.

[0178] A 50 mm × 50 mm square glass plate formed of non-alkali glass was prepared. This glass plate was washed with boiled isopropyl alcohol for 5 minutes and dried at 150 °C for 30 minutes or more.

[0179] Calcium was vapor-deposited on one side of the dried glass plate using a mask that covers the peripheral area at a distance of 0 mm to 2 mm from the edge of the glass plate. As a result, a calcium film (purity 99.8%) with a thickness of 200 nm was formed on the central portion of one side of the glass plate excluding the peripheral area at a distance of 0 mm to 2 mm from the edge of the glass plate.

[0180] In a nitrogen atmosphere, the hygroscopic layer on the element side of the above-mentioned test sheet and the surface of the glass plate on the calcium film side were bonded using a thermal laminator ("Lami Packer DAiSY A4 (LPD2325)" manufactured by Fujipla Co., Ltd.) to obtain a laminate. This laminate was used as an evaluation sample.

[0181] Generally, when calcium comes into contact with water and turns into calcium oxide, it becomes transparent. Also, in the above-mentioned evaluation sample, since the glass plate and the aluminum foil have a sufficiently high water vapor barrier property, moisture usually moves in the in-plane direction (the direction perpendicular to the thickness direction) through the end of the sealing layer and reaches the calcium film. When moisture penetrates into the evaluation sample, the calcium film is gradually oxidized from the end and becomes transparent, so a reduction in the calcium film is observed. Therefore, the ingress of moisture into the evaluation sample can be evaluated by measuring the sealing distance (mm) from the end of the evaluation sample to the calcium film. Thus, an evaluation sample containing a calcium film can be used as a model of an electronic device.

[0182] First, the sealing distance X2 (mm) from the end of the evaluation sample to the end of the calcium film was measured with a microscope ("Measuring Microscope MF-U" manufactured by Mitutoyo).

[0183] Next, the evaluation sample was placed in a thermo-hygrostat set at a temperature of 85°C and a humidity of 85% RH. When the sealing distance X1 (mm) between the end of the evaluation sample placed in the thermo-hygrostat and the end of the calcium film increased by 0.1 mm from the initial sealing distance X2, the evaluation sample was taken out of the thermo-hygrostat. The time from when the evaluation sample was placed in the thermo-hygrostat to when it was taken out of the thermo-hygrostat was determined as the start time of reduction t [hour]. This start time of reduction t is from the time point T P1 when the evaluation sample was placed in the thermo-hygrostat to the time point T P2 when the sealing distance X1 [mm] between the end of the evaluation sample placed in the thermo-hygrostat and the end of the calcium film becomes "X2 + 0.1 mm".

[0184] The above-mentioned sealing distance X1 and start time of reduction t were applied to Fick's diffusion equation of Equation (1) to calculate the constant K as a water vapor barrier property parameter.

[0185]

Equation

[0186] Using the obtained constant K, the water vapor intrusion barrier property of the sealing layer was evaluated according to the following criteria. The smaller the value of the constant K, the higher the water vapor intrusion barrier property. Here, "hr" below means "hour". The results are shown in Tables 2-1 to 2-3 below. Note that "(cm / hr^0.5)" in Tables 2-1 to 2-3 means "(cm / hr 0.5 )". (Criteria for water vapor intrusion barrier property) 〇 (Good): The constant K is less than 0.025 cm / h 0.5 Less than × (Poor): The constant K is 0.025 cm / hr or more 0.5 Or more

[0187] <Method for evaluating transparency> The sealing sheets prepared in the examples and comparative examples were cut into a length of 70 mm and a width of 25 mm. The protective sheet was peeled off from the cut sealing sheet, and the sealing sheet having a laminated structure of the sealing layer / support was laminated on a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., "White Slide Glass S1112 Edge Grinding No. 2", length: 76 mm, width: 26 mm, and thickness: 1.2 mm) using a batch vacuum laminator (manufactured by Nichigo-Morton Co., Ltd., V-160) to obtain an evaluation sample having a laminated structure of glass / sealing layer / support. The lamination conditions were a temperature of 80°C, a reduced pressure time of 30 seconds, and then a pressure of 0.3 MPa for 30 seconds of pressurization.

[0188] The haze (%) of the sample was measured in accordance with JIS K 7136. Specifically, after peeling off the support layer of the evaluation sample having a laminated structure of glass / sealing layer / support, using a haze meter HZ-V3 (halogen lamp) manufactured by Suga Test Instruments Co., Ltd., with glass as a reference, the haze (%) of the evaluation sample with the support peeled off was measured under D65 light, and the transparency was evaluated according to the following criteria. The results are shown in Tables 2-1 to 2-3 below. (Criteria for transparency) ○ (Good): The haze is less than 30% △ (Fair): The haze is 30% or more and less than 60% ×(Defect): Haze is 60% or more

[0189]

Table 1-1

[0190]

Table 1-2

[0191]

Table 2-1

[0192]

Table 2-2

[0193]

Table 2-3

[0194] The sealing layers of the sealing sheets of Examples 1 to 9 that meet the requirements of the present invention were superior in water vapor intrusion barrier properties compared to the sealing layers of the sealing sheets of Comparative Examples 1 to 3 that do not meet the requirements of the present invention.

Industrial Applicability

[0195] The sealing sheet of the present invention is useful for sealing, for example, electronic devices (such as organic EL devices, solar cells, sensor devices, touch panels having a conductive substrate, etc.).

Claims

1. A sealing sheet having a laminated structure including a support and a sealing layer, wherein the sealing layer is composed of a first moisture-absorbing layer and a second moisture-absorbing layer, the first moisture-absorbing layer contains the following components (A) and (B): (A) an olefin-based polymer, and (B) semi-calcined hydrotalcite and the second moisture-absorbing layer contains the following components (C) and (D): (C) an olefin-based polymer, and (D) calcium oxide A sealing sheet.

2. The sealing sheet according to claim 1, wherein the component (C) in the second moisture-absorbing layer contains an olefin-based polymer having an acid anhydride group and / or a carboxy group, and the median diameter of the component (D) in the second moisture-absorbing layer is 1 to 300 nm.

3. The sealing sheet according to claim 2, wherein the olefin-based polymer having an acid anhydride group and / or a carboxy group contained in the component (C) in the second moisture-absorbing layer is an olefin-based polymer having an acid anhydride group.

4. The sealing sheet according to claim 2 or 3, wherein the component (C) in the second moisture-absorbing layer contains an olefin-based polymer having an epoxy group.

5. The sealing sheet according to claim 4, wherein the olefin-based polymer having an acid anhydride group and / or a carboxy group and the olefin-based polymer having an epoxy group contained in the component (C) in the second moisture-absorbing layer form a crosslinked structure.

6. The sealing sheet according to any one of claims 1 to 5, wherein the first moisture-absorbing layer is in direct contact with the second moisture-absorbing layer.

7. The sealing sheet according to any one of claims 1 to 6, wherein the content of the component (B) is 10 to 80% by mass based on the entire first moisture-absorbing layer.

8. The sealing sheet according to any one of claims 1 to 7, wherein the content of the component (D) is 10 to 80% by mass based on the entire second moisture-absorbing layer.

9. The sealing sheet according to any one of claims 1 to 8, wherein the component (A) in the first moisture-absorbing layer includes an olefin-based polymer having an acid anhydride group and / or a carboxy group, and an olefin-based polymer having an epoxy group.

10. The sealing sheet according to claim 9, wherein the olefin-based polymer having an acid anhydride group and / or a carboxy group contained in the component (A) in the first moisture-absorbing layer is an olefin-based polymer having an acid anhydride group.

11. The sealing sheet according to claim 9 or 10, wherein the olefin-based polymer having an acid anhydride group and / or a carboxy group contained in the component (A) in the first moisture-absorbing layer and the olefin-based polymer having an epoxy group form a crosslinked structure.

12. The sealing sheet according to any one of claims 1 to 11, wherein one or both of the component (A) in the first moisture-absorbing layer and the component (C) in the second moisture-absorbing layer include a liquid olefin-based polymer.

13. The sealing sheet according to any one of claims 1 to 12, wherein one or both of the first and second moisture-absorbing layers include a tackifier.

14. The sealing sheet according to any one of claims 1 to 13, wherein the thickness of the sealing layer is 3 to 200 μm.

15. The sealing sheet according to any one of claims 1 to 14, wherein the ratio of the thickness of the second moisture-absorbing layer to the thickness of the first moisture-absorbing layer (thickness of the second moisture-absorbing layer / thickness of the first moisture-absorbing layer) is 0.05 to 2.

0.

16. The sealing sheet according to any one of claims 1 to 15, wherein the haze of the sealing layer is less than 60%.

17. An electronic device including a sealing layer formed from the sealing sheet according to any one of claims 1 to 16.

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