Sealing composition and sealing sheet

Abstract

To provide a sealing composition capable of forming a sealing layer with minimal moisture ingress and with outstanding water vapor barrier and adhesive strength.SOLUTION: A sealing composition comprises glycerol-containing hydrotalcites and olefinic polymers.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an encapsulating composition and an encapsulating sheet that are useful for encapsulating electronic devices. [Background technology]

[0002] To protect electronic devices such as organic electroluminescence (EL) devices and solar cells from moisture, electronic devices are encapsulated using encapsulating layers formed from encapsulating compositions or encapsulating sheets. Patent Document 1, for example, discloses an encapsulating resin composition containing (A) a polyolefin resin and (B) a metal hydroxide selected from the group consisting of hydrotalcite and semi-calcined hydrotalcite, as well as an encapsulating sheet formed therefrom, which exhibits both excellent moisture resistance and transparency. However, hydrotalcite reversibly absorbs and releases moisture. Therefore, in encapsulating compositions using hydrotalcite, moisture absorbed by the hydrotalcite during the production process or distribution process may be released in the encapsulating layer of an electronic device formed using the composition, potentially resulting in deterioration of the electronic device.

[0003] To improve the performance of devices that are sensitive to moisture, such as organic electroluminescence (EL) devices and solar cells, sealing compositions are required to have barrier properties against water vapor penetration (hereinafter, sometimes referred to as "water vapor penetration barrier properties"). To this end, sealing compositions using hydrotalcite have been proposed. Increasing the amount of hydrotalcite in the sealing composition can improve the water vapor penetration barrier properties, but this reduces the adhesiveness of the sealing layer formed from the sealing composition. Furthermore, increasing the amount of hydrotalcite increases the effect of interlayer water present in the hydrotalcite, resulting in a problem of increasing the amount of moisture carried over by the hydrotalcite into the sealing layer formed from the sealing composition.

[0004] On the other hand, Non-Patent Document 1 describes the use of glycerin-containing hydrotalcite as a catalyst for transesterification, but does not describe or suggest the use of glycerin-containing hydrotalcite as a moisture absorbent in a sealing composition. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2017 / 057708 [Non-patent literature]

[0006] [Non-Patent Document 1] Clays and Clay Minerals, Vol. 58, No. 4, 475-485, 2010 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a sealing composition that can form a sealing layer that is less likely to carry over moisture and has excellent water vapor penetration barrier properties and adhesiveness. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above-mentioned object can be achieved by using glycerin-containing hydrotalcite instead of conventional hydrotalcite. Based on this finding, the present invention is as follows.

[0009] [1] A sealing composition comprising a glycerin-containing hydrotalcite and an olefin polymer. [2] The sealing composition according to [1], wherein the glycerin-containing hydrotalcite contains the glycerin between layers of the hydrotalcite. [3] The sealing composition according to [1] or [2], wherein the amount of glycerin in the glycerin-containing hydrotalcite is 1 to 20% by mass relative to the glycerin-containing hydrotalcite. [4] The encapsulating composition according to any one of [1] to [3], wherein the olefin-based polymer comprises an olefin-based polymer having an epoxy group and an olefin-based polymer having an acid anhydride group and / or a carboxyl group. [5] A sheet for encapsulation having a laminated structure including a support and an encapsulating layer formed from the encapsulating composition according to any one of the above [1] to [4]. [6] An electronic device comprising a sealing layer formed from the sealing composition according to any one of [1] to [4] above. [7] A conductive substrate comprising a sealing layer formed from the sealing composition according to any one of [1] to [4] above. [Effects of the Invention]

[0010] According to the present invention, it is possible to obtain a sealing composition that can form a sealing layer that is less likely to carry over moisture and has excellent water vapor barrier properties and adhesiveness. DETAILED DESCRIPTION OF THE INVENTION

[0011] Sealing composition The sealing composition of the present invention is characterized by containing a glycerin-containing hydrotalcite and an olefin polymer. The components in the sealing composition of the present invention may be used alone or in combination of two or more. Each component will be described below in order.

[0012] <Glycerin-containing hydrotalcite> In this specification, the term "hydrotalcite" is a concept that includes hydrotalcite-like compounds such as natural hydrotalcite and synthetic hydrotalcite.

[0013] The typical composition formula of natural hydrotalcite is Mg6Al2(OH) 16It is a metal hydroxide having a layered crystal structure and is CO3·4H2O. The layer [Mg 1-X Al X (OH)2] X+ and the intermediate layer [(CO3) X / 2 ·mH2O] X- consist of.

[0014] Examples of the hydrotalcite-like compound include those represented by the following formula (I) and the following formula (II).

[0015] [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- .

[0016] M 2+ x Al2(OH) 2x+6-nz (A n- ) z ·mH2O (II) (In the formula, M 2+ represents a divalent metal ion such as Mg 2+ , Zn 2+ , etc., A n-is CO3 2- , Cl - , NO3 - represents an n-valent anion such as, where x is a positive number of 2 or more, z is a positive number of 2 or less, m is a positive number, and n is a positive number. In formula (II), M 2+ is preferably Mg 2+ and A n- is preferably CO3 2- is.

[0017] In the present invention, metal hydroxides having a layered crystal structure in which the amount of interlayer water is reduced or eliminated, which are obtained by calcining the above-mentioned natural hydrotalcite or hydrotalcite-like compound, can also be used as hydrotalcite. When explained using a compositional formula, "interlayer water" refers to "H2O" described in the compositional formula of the above-mentioned uncalcined natural hydrotalcite and hydrotalcite-like compound.

[0018] In this specification, "glycerin-containing hydrotalcite" means hydrotalcite that contains glycerin inside. The glycerin-containing hydrotalcite is preferably one that contains the glycerin between the layers of the hydrotalcite.

[0019] The glycerin in the glycerin-containing hydrotalcite may be in an electrically neutral form (ie, glycerin itself) or in an anionic form (ie, glycerolate anion formed by dissociating a proton from glycerin).

[0020] Because glycerin-containing hydrotalcite contains glycerin inside the hydrotalcite, the amount of water (especially interlayer water) contained inside is reduced compared to conventional hydrotalcite that does not contain glycerin. Therefore, by using glycerin-containing hydrotalcite instead of conventional hydrotalcite, it is possible to reduce the amount of moisture carried over into the sealing layer. Furthermore, because glycerin itself is hygroscopic, using glycerin-containing hydrotalcite instead of conventional hydrotalcite can improve the water vapor barrier properties of the sealing layer. Furthermore, as shown by comparison between the examples and comparative examples described below, using glycerin-containing hydrotalcite instead of conventional hydrotalcite can form a sealing layer with excellent adhesiveness.

[0021] From the viewpoints of suppressing moisture carryover and improving water vapor barrier properties and adhesiveness, the amount of glycerin in the glycerin-containing hydrotalcite is preferably 1 to 20 mass%, more preferably 1 to 15 mass%, and even more preferably 1 to 10 mass% relative to the glycerin-containing hydrotalcite (i.e., the total of glycerin and hydrotalcite). Furthermore, by using a glycerin-containing hydrotalcite with a glycerin amount of 10 mass% or less, a sealing layer with a low haze value can be formed.

[0022] The particle size of the glycerin-containing hydrotalcite is preferably 1 to 1,500 nm, more preferably 10 to 1,200 nm, which is the median size of the particle size distribution determined on a volume basis by laser diffraction / scattering particle size distribution measurement (JIS Z 8825).

[0023] The content of the glycerin-containing hydrotalcite in the sealing composition is preferably 5 to 80 mass %, more preferably 10 to 70 mass %, and even more preferably 10 to 60 mass %, based on the non-volatile content of the sealing composition, from the viewpoints of suppressing moisture carryover and improving water vapor barrier properties and adhesiveness.

[0024] The glycerin-containing hydrotalcite to be used may be one produced by a known method, such as that described in Non-Patent Document 1, or one available from a manufacturer such as Kyoeisha Chemical Co., Ltd.

[0025] The sealing composition may contain a hygroscopic filler other than the glycerin-containing hydrotalcite (hereinafter referred to as "other hygroscopic filler"). Examples of the other hygroscopic filler include semi-calcined hydrotalcite, calcined hydrotalcite, calcium oxide, magnesium oxide, and molecular sieve. The other hygroscopic filler may be used alone or in combination of two or more. The content of the other hygroscopic filler is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, even more preferably 0 to 20% by mass, even more preferably 0 to 10% by mass, and particularly preferably 0 to 5% by mass, based on the nonvolatile content of the sealing composition.

[0026] <Olefin polymer> One of the features of the present invention is the use of an olefin-based polymer, which improves the hydrophobicity of the resulting sealing layer, thereby improving the water vapor barrier properties of the sealing layer.

[0027] In this specification, "olefin polymer" means a polymer in which structural units derived from olefins (hereinafter sometimes abbreviated as "olefin units") are the main structural units (i.e., the amount of olefin units is the largest among all structural units). Note that, hereinafter, "structural units derived from butene," which are olefin units, may be abbreviated as "butene units," etc.

[0028] The olefin polymer may be an olefin resin (e.g., a propylene-butene copolymer) or an olefin rubber (e.g., a butyl rubber, i.e., an isobutene-isoprene copolymer). In this specification, "olefin resin" means an olefin polymer that cannot form a rubber elastomer by crosslinking, and "olefin rubber" means an olefin polymer that can form a rubber elastomer by crosslinking.

[0029] The olefin is preferably a monoolefin having one olefinic carbon-carbon double bond and / or a diolefin having two olefinic carbon-carbon double bonds. Examples of monoolefins include α-olefins such as ethylene, propylene, 1-butene, isobutene (isobutylene), 1-pentene, 1-hexene, 1-heptene, and 1-octene. Examples of diolefins include 1,3-butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethylbutadiene.

[0030] The olefin-based polymer may be a homopolymer or a copolymer. The copolymer may be a random copolymer or a block copolymer. The olefin-based polymer may also be a copolymer of an olefin and a monomer other than an olefin. Examples of the olefin-based copolymer include an ethylene-non-conjugated diene copolymer, an ethylene-propylene copolymer, an ethylene-propylene-non-conjugated diene copolymer, an ethylene-butene copolymer, a propylene-butene copolymer, a propylene-butene-non-conjugated diene copolymer, an isobutene-isoprene copolymer, a styrene-isobutene copolymer, and a styrene-isobutene-styrene copolymer.

[0031] The olefin polymer used in the present invention preferably contains an olefin polymer having an epoxy group and an olefin polymer having an acid anhydride group and / or a carboxy group. By using such a combination, a crosslinked structure can be formed in the sealing layer, resulting in the formation of a sealing layer that can suppress a decrease in adhesive strength even when stored under high-humidity and high-temperature conditions (i.e., has good wet-heat resistance). Hereinafter, the olefin polymer having an epoxy group and the olefin polymer having an acid anhydride group and / or a carboxy group will be described in turn.

[0032] From the viewpoint of forming a sealing layer having excellent water vapor barrier properties, the content of the olefin polymer in the sealing composition is preferably 1 mass % or more, more preferably 2 mass % or more, even more preferably 3 mass % or more, particularly preferably 7 mass % or more, particularly more preferably 14 mass % or more, and most preferably 21 mass % or more, and is preferably 70 mass % or less, more preferably 60 mass % or less, based on the non-volatile content of the sealing composition.

[0033] The epoxy group concentration in the epoxy group-containing olefin polymer is preferably 0.05 to 10 mmol / g, more preferably 0.10 to 5 mmol / g, from the viewpoint of achieving a more appropriate range for the crosslink density of the sealing layer and a balance between suppressing bubble generation and adhesiveness. The epoxy group concentration is determined from the epoxy equivalent obtained in accordance with JIS K 7236-1995.

[0034] The number-average molecular weight of the olefin polymer having epoxy groups is preferably 1,000 to 1,000,000, more preferably 2,000 to 800,000, and even more preferably 2,000 to 700,000, from the viewpoint of ensuring a more appropriate range of fluidity for the sealing composition and achieving a balance between bubble suppression and adhesiveness. The number-average molecular weight of each component is measured by gel permeation chromatography (GPC) (polystyrene equivalent). Specifically, the number-average molecular weight measured by GPC is measured using a Shimadzu LC-9A / RID-6A measuring instrument, a Showa Denko Shodex K-800P / K-804L / K-804L column, toluene, or the like, as the mobile phase, at a column temperature of 40°C, and can be calculated using a calibration curve for standard polystyrene.

[0035] An olefin polymer having an epoxy group can be obtained, for example, by graft-modifying an olefin 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.

[0036] The olefin polymer having an epoxy group can be, for example, a polymer available from Seiko PMC Co., Ltd. Examples of such polymers available from Seiko PMC include "ER829" (glycidyl methacrylate-modified propylene-butene random copolymer), "ER850" (glycidyl methacrylate-modified butyl rubber), "ER853" (glycidyl methacrylate-modified propylene-butene random copolymer), "ER866" (glycidyl methacrylate-modified butyl rubber), "T-YP276" (glycidyl methacrylate-modified propylene-butene random copolymer), and "T-YP313" (glycidyl methacrylate-modified propylene-butene random copolymer).

[0037] The olefin polymer having an epoxy group is preferably an isobutene-isoprene copolymer having an epoxy group (ie, butyl rubber).

[0038] When an isobutene-isoprene copolymer having an epoxy group (i.e., butyl rubber) is used as the olefin polymer having an epoxy group, the amount of isoprene units in the copolymer is preferably 0.1 to 10 mass%, more preferably 0.3 to 5 mass%, and even more preferably 0.5 to 3 mass%, based on the total amount of isobutene units and isoprene units, from the viewpoint of flexibility and moisture resistance of the sealing layer. The amount of isoprene units is based on the isobutene units and isoprene units excluding modified portions (e.g., portions derived from glycidyl (meth)acrylate for introducing epoxy groups).

[0039] When an olefin polymer having an epoxy group is used, the content thereof in the encapsulating composition is, from the viewpoint of moisture resistance of the encapsulating layer, preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and is preferably 70% by mass or less, more preferably 64% by mass or less, even more preferably 60% by mass or less, particularly preferably 58% by mass or less, particularly even more preferably 50% by mass or less, and most preferably 42% by mass or less, based on the non-volatile content of the encapsulating composition.

[0040] Next, an olefin polymer having an acid anhydride group (i.e., a carbonyloxycarbonyl group (—CO—O—CO—)) and / or a carboxy group will be described. When an olefin polymer having an acid anhydride group is used as the olefin polymer having an acid anhydride group and / or a carboxy group, the concentration of the acid anhydride group in the polymer is preferably 0.05 to 10 mmol / g, more preferably 0.1 to 5 mmol / g, from the viewpoint of achieving a more appropriate range for the crosslink density of the sealing layer and a balance between suppressing bubble generation and adhesiveness. The concentration of the acid anhydride group is determined from the acid value, which is defined as the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of polymer, as described in JIS K 2501.

[0041] When an olefin polymer having a carboxy group is used as the olefin polymer having an acid anhydride group and / or a carboxy group, the concentration of the carboxy group in the polymer is preferably 0.1 to 20 mmol / g, more preferably 0.2 to 10 mmol / g, from the viewpoint of balancing the suppression of bubble generation and adhesiveness. The concentration of the carboxy group is obtained from the acid value, which is defined as the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of polymer, according to JIS K 2501.

[0042] 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 concentration of the acid anhydride group and the carboxy group in the polymer is preferably 0.1 to 20 mmol / g, more preferably 0.2 to 10 mmol / g, from the viewpoint of balancing the suppression of bubble generation and adhesiveness.

[0043] 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 2,000 to 800,000, and even more preferably 2,000 to 700,000, from the viewpoint of making the fluidity of the sealing composition more appropriate and achieving a balance between suppressing bubble generation and adhesiveness.

[0044] The olefin polymer having an acid anhydride group and / or a carboxy group is preferably an isobutene-isoprene copolymer having an acid anhydride group and / or a carboxy group (i.e., butyl rubber), and / or a polybutene having an acid anhydride group and / or a carboxy group, more preferably an isobutene-isoprene copolymer having an acid anhydride group and / or a polybutene having an acid anhydride group, and even more preferably an isobutene-isoprene copolymer having an acid anhydride group and a polybutene having an acid anhydride group.

[0045] When an isobutene-isoprene copolymer (i.e., butyl rubber) having an acid anhydride group and / or a carboxy group (preferably an acid anhydride group) is used as the olefin polymer having an acid anhydride group and / or a carboxy group, the amount of isoprene units in the copolymer is preferably 0.1 to 5 mass%, more preferably 0.2 to 3 mass%, based on the total of isobutene units and isoprene units, from the viewpoint of flexibility and moisture resistance of the sealing layer. The amount of isoprene units is based on the isobutene units and isoprene units excluding modified portions (e.g., portions derived from maleic anhydride, portions derived from maleic anhydride-(meth)acrylate copolymers, etc., used to introduce acid anhydride groups).

[0046] An olefin polymer having an acid anhydride group and / or a carboxy group can be produced, for example, by 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.

[0047] As the olefin polymer having an acid anhydride group and / or a carboxy group, a polymer available from a manufacturer can be used. Examples of such polymers include "ER641" (maleic anhydride-modified butyl rubber), "ER645" (maleic anhydride-butyl methacrylate random copolymer-modified propylene-butene random copolymer), "ER661" (maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber), "ER669" (maleic anhydride-2-ethylhexyl acrylate random copolymer-modified butyl rubber, "ER674" (maleic anhydride-lauryl methacrylate random copolymer-modified butyl rubber), and "ER688" (maleic anhydride-butyl methacrylate random copolymer-modified polybutene), all manufactured by Seiko PMC Corporation; "HV-300M" (maleic anhydride-modified liquid polybutene) manufactured by Toho Chemical Industry Co., Ltd.; and "LUCANT A-5515" (acid-modified ethylene-α-olefin copolymer), "LUCANT A-5260" (acid-modified ethylene-α-olefin copolymer), and "LUCANT A-5320H" (acid-modified ethylene-α-olefin copolymer) manufactured by Mitsui Chemicals, Inc.

[0048] When an olefin polymer having an acid anhydride group and / or a carboxy group is used, the content thereof in the encapsulating composition is, from the viewpoint of moisture resistance of the encapsulating layer, preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and is preferably 70% by mass or less, more preferably 64% by mass or less, even more preferably 60% by mass or less, particularly preferably 58% by mass or less, particularly even more preferably 50% by mass or less, and most preferably 42% by mass or less, based on the non-volatile content of the encapsulating composition.

[0049] When an olefin polymer having an epoxy group and an olefin polymer having an acid anhydride group and / or a carboxy group are used, the ratio of "the amount (mol) of epoxy groups in the olefin polymer having an epoxy group" to "the total amount (mol) of acid anhydride groups and carboxy groups in the olefin polymer having an acid anhydride group and / or a carboxy group" is not particularly limited as long as a crosslinked structure can be formed, but is preferably 100:20 to 100:1000, more preferably 100:50 to 100:950, and even more preferably 100:80 to 100:900. For example, when the olefin polymer having an acid anhydride group and / or a carboxy group has only acid anhydride groups, the "total amount (mol) of acid anhydride groups and carboxy groups" refers to the "amount (mol) of acid anhydride groups."

[0050] When an isobutene-isoprene copolymer (i.e., butyl rubber) is used as the olefin polymer, the amount of the isobutene-isoprene copolymer in the olefin polymer is preferably 50 to 95 mass%, more preferably 50 to 90 mass%, and even more preferably 55 to 85 mass%, based on the olefin polymer, from the viewpoints of adhesion at low and high temperatures and flexibility. The isobutene-isoprene copolymer may have a functional group (e.g., an epoxy group, or an acid anhydride group and / or a carboxy group).

[0051] In order to impart good adhesion and flexibility to the sealing layer, the olefin polymer used in the present invention preferably includes a liquid olefin polymer having no epoxy groups, acid anhydride groups, or carboxy groups (hereinafter, sometimes simply referred to as a "liquid olefin polymer" or an "unmodified liquid olefin polymer"). In this specification, the term "liquid" in "liquid olefin polymer" means that the viscosity at 25°C is 5,000 Pa·s or less. In addition, in the present invention, the term "viscosity at 25°C" refers to the viscosity calculated by multiplying the kinematic viscosity at 25°C measured with a dynamic viscoelasticity measuring device by the density. An example of a dynamic viscoelasticity measuring device is a rheometer (trade name: DISCOVERY HR-2) manufactured by TA Instruments.

[0052] The viscosity of the unmodified liquid olefin polymer at 25° C. is preferably 50 to 5,000 Pa·s, more preferably 100 to 4,000 Pa·s, and even more preferably 200 to 3,000 Pa·s, from the viewpoint of providing adhesiveness and tack to the sealing layer.

[0053] The number average molecular weight of the unmodified liquid polyolefin polymer is not particularly limited, but is preferably 100 to 50,000, more preferably 200 to 30,000, and even more preferably 300 to 20,000.

[0054] The unmodified liquid olefin polymer can be a polymer available from a manufacturer. Examples of such polymers include "HV-300" (liquid polybutene), "HV-1900" (liquid polybutene), "HV-50" (liquid polybutene), and "HV-35" (liquid polybutene) manufactured by ENEOS Corporation; "950MW" (liquid polybutene) and "2400MW" (liquid olefin polymer) manufactured by Kothari; "H-1900" (liquid polybutene), "H-6000" (liquid polybutene), and "H-18000" (liquid polybutene) manufactured by INEOS Corporation; and "200N" manufactured by NOF Corporation. "(liquid polybutene)"; "BI-2000" (hydrogenated polybutadiene), "BI-3000" (hydrogenated polybutadiene), "GI-3000" (hydrogenated polybutadiene), "B-1000" (liquid polybutadiene), "B-3000" (liquid polybutadiene), "G-3000" (liquid polybutadiene) manufactured by Nippon Soda Co., Ltd.; "Lucant LX100" (liquid olefin polymer) and "Lucant LX400" (liquid olefin polymer) manufactured by Mitsui Chemicals, Inc.; "Poly Examples include "Poly bd R-45HT" (liquid butadiene rubber), "Poly bd R-15HT" (liquid butadiene rubber), and "Poly ip" (liquid polyisoprene); Kuraray Co., Ltd.'s "LIR-30" (liquid polyisoprene), "LIR-390" (liquid polyisoprene), "LIR-290" (liquid polyisoprene), "LBR-302" (liquid polybutadiene), "LBR-305" (liquid polybutadiene), "LBR-361" (liquid polybutadiene), and "L-SBR-820" (liquid styrene-butadiene random copolymer); and Cray Valley Co., Ltd.'s "Ricon 154" (liquid butadiene), and "RICON 184" (liquid styrene-butadiene random copolymer). The unmodified liquid olefin polymer is preferably liquid polybutene.

[0055] When an unmodified liquid olefin polymer is used, its content in the encapsulating composition is preferably 5 to 50 mass %, more preferably 10 to 45 mass %, and even more preferably 15 to 40 mass %, based on the non-volatile content of the encapsulating composition, from the viewpoints of the adhesiveness and flexibility of the encapsulating layer.

[0056] <Other ingredients> The sealing composition of the present invention may contain components other than the glycerin-containing hydrotalcite and the olefin-based polymer (hereinafter, sometimes referred to as "other components"), as long as the effects of the present invention are not impaired. Examples of other components include tackifiers, curing accelerators, antioxidants, etc. These may be used alone or in combination of two or more. These will be described in order below.

[0057] (tackifier) The tackifier is a component that imparts tackiness to the sealing composition. Examples of the tackifier include rosin resins, terpene resins, modified terpene resins (hydrogenated terpene resins, terpene-phenol copolymer resins, aromatic-modified terpene resins, etc.), petroleum resins (aliphatic petroleum resins, hydrogenated petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, copolymerized petroleum resins), coumarone-indene resins, alkylphenol resins, and xylene resins.

[0058] Commercially available tackifiers can be used. Examples of commercially available tackifiers include the following: Rosin-based resins include Pine Crystal ME-H, Pine Crystal ME-D, Pine Crystal ME-G, Pine Crystal KR-85, Pine Crystal KE-311, Pine Crystal KE-359, Pine Crystal D-6011, Pine Crystal PE-590, Pine Crystal KE-604, Pine Crystal PR-580 (all manufactured by Arakawa Chemical Industries, Ltd.), etc.

[0059] 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, and YS Resin CP (all manufactured by Yasuhara Chemical Co., Ltd.).

[0060] Examples of hydrogenated terpene resins include Clearon P, Clearon M, and Clearon K series (all manufactured by Yasuhara Chemical Co., Ltd.).

[0061] Examples of terpene phenol copolymer resins include YS Polystar 2000, Polystar U, Polystar T, Polystar S, and Mighty Ace G (all manufactured by Yasuhara Chemical Co., Ltd.).

[0062] Examples of aromatic modified terpene resins include YS Resin TO85, YS Resin TO105, YS Resin TO115, and YS Resin TO125 (all manufactured by Yasuhara Chemical Co., Ltd.).

[0063] Examples of hydrogenated petroleum resins include Escorez 5300 series and 5600 series (all manufactured by Exxon Mobil Corporation); T-REZ OP501, T-REZ PR803, T-REZ HA085, T-REZ HA103, T-REZ HA105, and T-REZ HA125 (all hydrogenated dicyclopentadiene-based petroleum resins, manufactured by ENEOS Corporation); Quintone 1325 and Quintone 1345 (all manufactured by Zeon Corporation); Imarv S-100, Imarv S-110, Imarv P-100, Imarv P-125, and Imarv P-140 (all hydrogenated dicyclopentadiene-based petroleum resins, manufactured by Idemitsu Kosan Co., Ltd.); Arcon P-90, Arcon P-100, Arcon P-115, Arcon P-125, Arcon P-140, and Arcon Examples include M-90, Alcon M-100, Alcon M-115, Alcon M-135, and TFS13-030 (all manufactured by Arakawa Chemical Industries, Ltd.).

[0064] Examples of aromatic petroleum resins include ENDEX155 (manufactured by Eastman Co.); 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, and Neopolymer EP-140 (all manufactured by ENEOS Corporation); Petokol LX, Petokol 120, Petokol 130, and Petokol 140 (all manufactured by Tosoh Corporation); and T-REZ RB093, T-REZ RC100, T-REZ RC115, T-REZ RC093, and T-REZ RE100 (all manufactured by ENEOS Corporation).

[0065] Examples of copolymer petroleum resins include T-REZ HB103, T-REZ HB125, T-REZ PR801, T-REZ PR802, and T-REZ RD104 (all manufactured by ENEOS Corporation); Petrotack 60, Petrotack 70, Petrotack 90, Petrotack 90HS, Petrotack 90V, and Petrotack 100V (all manufactured by Tosoh Corporation); and Quintone D100 (manufactured by Zeon Corporation).

[0066] From the viewpoint of the heat resistance of the sealing composition, the softening point of the tackifier is preferably 50 to 200° C., more preferably 90 to 180° C., and even more preferably 100 to 150° C. The softening point is measured by the ring and ball method in accordance with JIS K2207.

[0067] When a tackifier is used, the content thereof in the sealing composition is preferably 1 to 50 mass %, more preferably 5 to 45 mass %, and even more preferably 10 to 40 mass %, based on the nonvolatile content of the sealing composition.

[0068] (curing accelerator) A curing accelerator may be used to promote the crosslinking reaction between the epoxy groups of the epoxy-containing olefin polymer and the acid anhydride and / or carboxyl groups of the acid anhydride and / or carboxyl groups of the olefin polymer. Examples of the curing accelerator include imidazole compounds, tertiary and quaternary amine compounds, dimethylurea compounds, and organic phosphine compounds.

[0069] Examples of the imidazole compound include 1H-imidazole, 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2-phenyl-4,5-bis(hydroxymethyl)imidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-phenylimidazole, 2-dodecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. 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, and 2MA-OK (all manufactured by Shikoku Chemicals Corporation).

[0070] The tertiary and quaternary amine compounds are not particularly limited, and examples thereof include 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-phenolate, DBU-octylate, DBU-p-toluenesulfonate, DBU-formate, and DBU-phenol novolac resin salt; tertiary amines or salts thereof such as benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol (TAP); and dimethylurea compounds such as aromatic dimethylurea and aliphatic dimethylurea.

[0071] Examples of dimethylurea compounds include aromatic dimethylureas such as DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and U-CAT3512T (manufactured by San-Apro Co., Ltd.); and aliphatic dimethylureas such as U-CAT3503N (manufactured by San-Apro Co., Ltd.). Among these, aromatic dimethylureas are preferably used from the viewpoint of curability.

[0072] Examples of organic phosphine compounds include triphenylphosphine, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tri-tert-butylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, triphenylphosphine triphenylborane, etc. Specific examples of organic phosphine compounds include TPP, TPP-MK, TPP-K, TTBuP-K, TPP-SCN, TPP-S (all manufactured by Hokko Chemical Industry Co., Ltd.), etc.

[0073] When a curing accelerator is used, the content thereof in the sealing composition to promote the above-mentioned crosslinking reaction is not particularly limited as long as the crosslinking reaction is promoted, but is preferably 0.005 to 1 mass %, more preferably 0.010 to 0.5 mass %, and even more preferably 0.015 to 0.25 mass %, based on the non-volatile content of the sealing composition.

[0074] (antioxidant) In the present invention, there is no particular limitation on the antioxidant, and known antioxidants can be used.

[0075] Sealing sheet The present invention also provides an encapsulating sheet having a laminated structure including a support and a sealing layer formed from the encapsulating composition of the present invention. A protective sheet may be used in the present invention. That is, the encapsulating sheet of the present invention may have a laminated structure including a support, a sealing layer, and a protective sheet in this order. Another layer (e.g., a release layer) may be present between the support and the sealing layer and between the sealing layer and the protective sheet.

[0076] Examples of the support and 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; and plastic films such as polyimide. The support and protective sheet may both be single-layer films or laminate films.

[0077] The support and protective sheet may be, for example, a low-moisture-permeable film having a barrier layer, or a laminate film of a low-moisture-permeable film having a barrier layer and another film. Examples of barrier layers include inorganic films such as silica vapor deposition films, silicon nitride films, and silicon oxide films. The barrier layer may be composed of multiple layers of inorganic films (e.g., silica vapor deposition films). The barrier layer may also be composed of organic and inorganic materials, or may be a composite multilayer of organic and inorganic films.

[0078] The surface of the protective sheet that contacts the sealing layer is preferably release-treated. On the other hand, the support may or may not be release-treated. Examples of release treatments include release treatments using a release agent such as a silicone resin-based release agent, an alkyd resin-based release agent, or a fluororesin-based release agent.

[0079] The thicknesses of the support and the protective sheet are not particularly limited, but are preferably 10 to 150 μm, more preferably 20 to 100 μm, respectively, from the viewpoint of ease of handling of the encapsulating sheet. When the support and the protective sheet are laminate films, the thicknesses are those of the laminate films. On the other hand, the thickness of the encapsulating layer is preferably 1 to 200 μm, more preferably 3 to 150 μm, and even more preferably 5 to 100 μm, from the viewpoints of embedding property when laminating onto a substrate having irregularities and water vapor barrier performance. When the thickness of the encapsulating layer is 1 μm or more, the encapsulating layer can better conform to the irregularities, thereby further improving embedding property. When the thickness of the encapsulating layer is 200 μm or less, water vapor penetration from the cross section of the encapsulating layer can be better suppressed, thereby improving water vapor barrier performance.

[0080] The sealing layer in the sealing sheet is preferably transparent, and regardless of the thickness of the sealing layer, the haze value of the sealing layer is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. The haze value of a sealing layer having a thickness of 50 μm is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. The haze value can be measured by a method in accordance with JIS K 7136.

[0081] Production of encapsulating composition and encapsulating sheet The sealing composition of the present invention can be prepared by mixing the above-mentioned components using known equipment.

[0082] The sealing sheet of the present invention can be produced, for example, by (i) dissolving or dispersing the above-mentioned components in an organic solvent to prepare a varnish of a sealing composition, (ii) applying the obtained varnish to a support to form a coating film, and (iii) heating the obtained coating film to remove the organic solvent.

[0083] Examples of organic solvents that can be used to prepare the varnish 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 of dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and the like. Only one organic solvent may be used, or two or more may be used in combination. Commercially available organic solvents may also be used. Examples of commercially available organic solvents include "Swasol" manufactured by Maruzen Petrochemical Co., Ltd. and "Ipsol" manufactured by Idemitsu Kosan Co., Ltd. The varnish can be applied by any known method (e.g., a method using a die coater), and the application method is not particularly limited.

[0084] In order to promote the reaction between the epoxy groups of the olefin polymer having epoxy groups and the acid anhydride groups and / or carboxy groups of the olefin polymer having acid anhydride groups and / or carboxy groups, the organic solvent is preferably removed by heating the coating film. The heating temperature of the coating film is preferably 80 to 200°C, more preferably 100 to 180°C, and the heating time is preferably 2 to 90 minutes, more preferably 5 to 60 minutes. The heating of the coating film may be carried out under normal pressure or under reduced pressure.

[0085] Uses of the encapsulating composition and the encapsulating sheet The encapsulating composition and encapsulating sheet of the present invention can be used to encapsulate electronic devices, conductive substrates, etc. Examples of electronic devices include organic EL devices, solar cells, and sensor devices. Examples of solar cells include organic thin-film solar cells (OPV), perovskite solar cells (PSC), and dye-sensitized solar cells (DSSC). Examples of conductive substrates include substrates using indium tin oxide (ITO) and substrates using silver nanowires (AgNWs). [Example]

[0086] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and it is of course possible to carry out the invention by making appropriate modifications within the scope that can comply with the above and below spirit, and all such modifications are included in the technical scope of the present invention. Unless otherwise specified, the "%" and "parts" below for reflectance, transmittance, haze value, etc. mean "% by mass" and "parts by mass", respectively.

[0087] <Ingredients> The components used in the examples and comparative examples are shown below. (1) Olefin polymer "ER866" (Seiko PMC Corporation, 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%) "ER661" (manufactured by Seiko PMC Corporation, maleic anhydride-butyl methacrylate random copolymer modified butyl rubber, butyl methacrylate unit concentration: 0.32 mmol / g, acid anhydride group concentration: 0.46 mmol / g, number average molecular weight: 40,000, isobutene unit / isoprene unit ratio: 98.9% / 1.1%) "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) "HV-1900" (ENEOS Corporation, liquid polybutene, number average molecular weight: 2,900, viscosity at 25°C: 460 Pa·s)

[0088] (2) Hydrotalcite or glycerin-containing hydrotalcite "DHT-4C" (manufactured by Kyowa Chemical Industry Co., Ltd., hydrotalcite containing no glycerin, median diameter: 400 nm, hereinafter referred to as "hydrotalcite") "Barriasite W-3" (Kyoeisha Chemical Co., Ltd., glycerin-containing hydrotalcite with a glycerin content of 3%, median diameter: 700 nm, hereinafter referred to as "HT-Gly 3%") "Barriasite W-5" (Kyoeisha Chemical Co., Ltd., glycerin-containing hydrotalcite with a glycerin content of 5%, median diameter: 800 nm, hereinafter referred to as "HT-Gly 5%") "Barriasite W-15" (manufactured by Kyoeisha Chemical Co., Ltd., glycerin-containing hydrotalcite with a glycerin content of 15%, median diameter: 800 nm, hereinafter referred to as "HT-Gly 15%")

[0089] (3) Tackifier "Alcon P125" (Arakawa Chemical Co., Ltd., saturated hydrocarbon resin containing cyclohexane ring)

[0090] (4) Curing accelerator 2,4,6-tris(dimethylaminomethyl)phenol (manufactured by Kayaku Nouryon Co., Ltd., hereinafter referred to as "TAP")

[0091] Example 1 Varnishes having the blending ratios shown in the following table were prepared by the following procedure, and encapsulating sheets were prepared using the obtained varnishes. The amount (parts) of each component used in the following table indicates the amount of non-volatile content of each component in the varnish.

[0092] Specifically, a mixture was prepared by dispersing maleic anhydride-modified liquid polybutene (HV-300M), liquid polybutene (HV-1900), and glycerin-containing hydrotalcite (HT-Gly 3%) in a 60% nonvolatile solution of tackifier (Alcon P125) using a triple-roll mill. The resulting mixture was then mixed with a 40% nonvolatile solution of glycidyl methacrylate-modified butyl rubber (ER866) in toluene, a 40% nonvolatile solution of maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber (ER661) in toluene, a curing accelerator (TAP), and toluene. The resulting mixture was uniformly dispersed in a high-speed mixer to obtain a sealing composition varnish. The obtained varnish was uniformly applied using a die coater onto the release-treated surface of a polyethylene terephthalate (PET) film "SP4020" (PET: 50 μm: manufactured by Toyo Cross Co., Ltd.) that had been treated with a silicone-based release agent, and the film was heated at 130°C for 30 minutes, and then heated at 160°C for 30 minutes, thereby obtaining a sealing sheet having a sealing layer with a thickness of 50 μm.

[0093] <Example 2> A varnish of the sealing composition and a sealing sheet having a sealing layer with a thickness of 50 μm were prepared in the same manner as in Example 1, except that HT-Gly 5% was used instead of HT-Gly 3%.

[0094] Example 3 A varnish of the sealing composition and a sealing sheet having a sealing layer with a thickness of 50 μm were prepared in the same manner as in Example 1, except that HT-Gly 15% was used instead of HT-Gly 3%.

[0095] <Comparative Example 1> A varnish of the sealing composition and a sealing sheet having a sealing layer with a thickness of 50 μm were produced in the same manner as in Example 1, except that hydrotalcite (DHT-4C) was used instead of HT-Gly 3%.

[0096] The sealing layer of each of the sealing sheets obtained in Examples and Comparative Examples was evaluated for moisture content, water vapor barrier property by the "Ca test [time / 2 mm]" described later, and adhesiveness to aluminum foil or barrier layer by 90-degree peel strength. The results are shown in Table 1.

[0097] <Water to bring with you> The encapsulating sheets prepared in the examples and comparative examples were cut to a length of 70 mm and a width of 40 mm, folded, and placed in a thoroughly dried screw vial (VABH17, manufactured by Mitsubishi Chemical Analytech Co., Ltd.), which was then placed in an electric furnace (VA-236S, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) directly connected to a Karl Fischer analyzer (CA310, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). The temperature of the electric furnace was raised to 250°C in an N2 gas flow, and water desorbed from the measurement sample was collected in a Karl Fischer measurement solution, and the mass of the water was measured by a standard method. From the measured mass of water, the moisture content (ppm) of the sealing layer was calculated based on the mass of the entire sealing layer (sealing composition). The results are shown in the table below.

[0098] <Water vapor barrier properties> As a support film, a composite film "PET-Tsuki AL1N30" (aluminum foil thickness 30 μm, polyethylene terephthalate film thickness 25 μm, manufactured by Tokai Toyo Aluminum Sales Co., Ltd.) comprising aluminum foil and polyethylene terephthalate film was prepared. Except for using this support film instead of the PET film, a sealing layer was formed on the aluminum foil side of the support film in the same manner as in the manufacturing method of the sealing sheet in each example and comparative example. Thereby, a test sheet comprising a support film and a sealing layer was obtained.

[0099] A 50 mm x 50 mm square glass plate made of alkali-free glass was prepared, washed with boiled isopropyl alcohol for 5 minutes, and dried at 150°C for 30 minutes or more.

[0100] Calcium was vapor-deposited onto one side of the glass plate using a mask that covered the peripheral area 0 mm to 2 mm from the edge of the glass plate, thereby forming a 200 nm-thick calcium film (purity 99.8%) in the central part of one side of the glass plate, excluding the peripheral area 0 mm to 2 mm from the edge of the glass plate.

[0101] In a nitrogen atmosphere, the sealing layer of the test sheet described above and the calcium film side of the glass plate were bonded together using a thermal laminator (Fujipla Lamipacker DAiSY A4 (LPD2325)) to obtain a laminated evaluation sample.

[0102] Generally, calcium becomes transparent when it comes into contact with water and becomes calcium oxide. Furthermore, in the evaluation sample, the glass plate and aluminum foil have sufficiently high barrier properties against water vapor penetration, so moisture can usually migrate in the in-plane direction (perpendicular to the thickness direction) through the edge of the sealant layer and reach the calcium film. Therefore, when moisture penetrates the evaluation sample, the calcium film gradually oxidizes and becomes transparent from the edge, and shrinkage of the calcium film is observed. Therefore, moisture penetration into the evaluation sample can be evaluated by measuring the sealing distance [mm] from the edge of the evaluation sample to the calcium film. Therefore, the evaluation sample containing the calcium film can be used as a model for electronic devices.

[0103] First, the sealing distance X2 [mm] from the edge of the evaluation sample to the edge of the calcium film was measured using a microscope (Measuring Microscope MF-U, manufactured by Mitutoyo Corporation). Hereinafter, this sealing distance X2 will be referred to as the initial sealing distance X2.

[0104] Next, the evaluation sample was placed in a thermo-hygrostat chamber set at a temperature of 85°C and a humidity of 85% RH. The evaluation sample was removed from the thermo-hygrostat chamber when the sealing distance X1 (mm) between the end of the evaluation sample placed in the thermo-hygrostat chamber and the end of the calcium film increased by 0.1 mm from the initial sealing distance X2. The decrease start time t [hours] was calculated as the time from the time the evaluation sample was placed in the thermo-hygrostat chamber to the time the evaluation sample was removed from the thermo-hygrostat chamber. This decrease start time t corresponds to the time from the time TP1 when the evaluation sample was placed in the thermo-hygrostat chamber to the time TP2 when the sealing distance X1 [mm] between the end of the evaluation sample placed in the thermo-hygrostat chamber and the end of the calcium film became "X2 + 0.1 mm."

[0105] The sealing distance X1 and decrease start time t were applied to the Fick's diffusion equation of the following formula (1) to calculate a constant K as a water vapor penetration barrier property parameter.

[0106]

number

[0107] Using the obtained constant K, the time it takes for moisture to penetrate a width of 2 mm (Ca test [time / 2 mm]) was calculated, and the water vapor penetration barrier property was evaluated based on this.

[0108] <Adhesion to aluminum foil> In the examples and comparative examples, sealing sheets (50 mm long, 20 mm wide) using PET film as a support were laminated onto a composite film "PET-Tuki AL1N30" (aluminum foil thickness: 30 μm, PET film thickness: 25 μm, manufactured by Tokai Toyo Aluminum Sales Co., Ltd.) comprising aluminum foil and polyethylene terephthalate film using a batch vacuum laminator (Nichigo-Morton, Morton-724). Lamination was performed at a temperature of 80°C for 30 seconds at a pressure of 0.3 MPa. The PET film was then peeled off, and a glass plate (76 mm long, 26 mm wide, 1.2 mm thick, microslide glass) was laminated onto the exposed sealing layer under the same conditions as above. The 90° peel strength of the resulting laminate was measured when peeled at a 90° angle to the length of the aluminum foil at a pulling rate of 50 mm / min.

[0109] <Adhesion to barrier layer> The 90-degree peel strength was measured in the same manner, except that the "PET-attached AL1N30" used in the above <Adhesion to aluminum foil> was changed to a high-performance film "Belear 38U001" with a barrier layer on a PET film (barrier layer: layer made of SiOC formed by plasma CVD method, barrier layer thickness 0.5 μm, PET film thickness 38 μm, manufactured by Reikosha).

[0110] <Haze value measurement> The sealing sheet produced in the examples was cut to a length of 50 mm and a width of 20 mm, and the cut sealing sheet was laminated onto a glass plate (a microslide glass having a length of 76 mm, a width of 26 mm, and a thickness of 1.2 mm (manufactured by Matsunami Glass Industrial Co., Ltd., white slide glass S1112, edge polished No. 2) using a batch-type vacuum laminator (manufactured by Nichigo-Morton Co., Ltd., V-160) so that the sealing layer and the glass plate were in contact with each other. The lamination conditions were a temperature of 80°C, a decompression time of 30 seconds, and then a pressure of 0.3 MPa for 30 seconds. Thereafter, the PET film of the sealing sheet was peeled off, and the light transmittance spectrum of the exposed sealing layer was measured using a fiber spectrophotometer (MCPD-7700, model 311C, Otsuka Electric) equipped with a φ60 mm integrating sphere (model name SRS-99-010, reflectance 99%). Measurements were performed using an external light source unit (halogen lamp MC-2564, 24V, 150W specification) manufactured by a subsidiary company, and the total light transmittance (%) and diffuse transmittance (%) at a wavelength of 450 nm were calculated, and the haze value was calculated. The distance between the integrating sphere and the sample (laminate) was set to 0 mm, and glass was used as a reference. The haze value of the sealing layer in Example 1 was 2.7%, the haze value of the sealing layer in Example 2 was 1.4%, and the haze value of the sealing layer in Example 3 was 3.9%, confirming that transparent sealing layers were obtained in Examples 1 to 3.

[0111] [Table 1]

[0112] As shown in Table 1, the sealing layers obtained in Examples 1 to 3 using glycerin-containing hydrotalcite carried less moisture than the sealing layer obtained in Comparative Example 1 using hydrotalcite, and had excellent water vapor barrier properties, adhesion to aluminum foil, and adhesion to barrier layers. [Industrial Applicability]

[0113] The encapsulating composition and encapsulating sheet of the present invention are useful for encapsulating electronic devices.

Claims

1. Glycerin-containing hydrotalcite, an olefin polymer having an epoxy group; an olefin polymer having an acid anhydride group and / or a carboxy group; a liquid olefin polymer having no epoxy group, acid anhydride group or carboxy group; tackifiers, and Curing accelerator A sealing composition comprising: the content of the glycerin-containing hydrotalcite is 10 to 70 mass% based on the non-volatile content of the sealing composition; the content of the olefin polymer having an epoxy group is 2 to 60 mass % based on the nonvolatile content of the sealing composition; the content of the olefin polymer having an acid anhydride group and / or a carboxy group is 2 to 60 mass % based on the nonvolatile content of the sealing composition; the content of the liquid olefin polymer having none of an epoxy group, an acid anhydride group, or a carboxy group is 10 to 40 mass % based on the nonvolatile content of the sealing composition; the content of the tackifier is 5 to 40 mass% based on the non-volatile content of the sealing composition; the content of the curing accelerator is 0.005 to 1 mass % based on the nonvolatile content of the sealing composition; The glycerin-containing hydrotalcite contains the glycerin between the layers of the hydrotalcite; and A sealing composition, wherein the amount of glycerin in the glycerin-containing hydrotalcite is 1 to 20% by mass relative to the glycerin-containing hydrotalcite.

2. An encapsulating sheet having a laminated structure comprising a support and an encapsulating layer formed from the encapsulating composition according to claim 1.

3. An electronic device comprising an encapsulating layer formed from the encapsulating composition of claim 1.

4. A conductive substrate comprising a sealing layer formed from the sealing composition of claim 1.

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