KR20230136066A - Composition for sealing and sealing sheet - Google Patents

Abstract

[Problem] The present invention is to provide a sealing composition capable of forming a sealing layer with low moisture content and excellent water vapor intrusion barrier properties and adhesiveness.
[Solution] A sealing composition comprising glycerin-containing hydrotalcite and an olefin polymer.

Description

Sealing composition and sealing sheet {COMPOSITION FOR SEALING AND SEALING SHEET}

The present invention relates to a sealing composition and a sealing sheet useful for sealing electronic devices.

In order to protect electronic devices such as organic EL (Electroluminescence) devices and solar cells from moisture, sealing the electronic devices using a sealing layer formed from a sealing composition or a sealing sheet has been performed. As such a composition or sheet, for example, in Patent Document 1, a sealing resin composition comprising (A) a polyolefin-based resin, and (B) a metal hydroxide selected from the group consisting of hydrotalcite and semi-baked hydrotalcite. , and that the sealing sheet formed therefrom has both good moisture permeability resistance and transparency. However, hydrotalcite absorbs and releases moisture, reversibly. Therefore, in the sealing composition using hydrotalcite, the moisture absorbed by the hydrotalcite during the manufacturing process or distribution process is released in the sealing layer of the electronic device formed using the composition, resulting in deterioration of the electronic device. There are cases where it happens.

In order to improve the performance of devices vulnerable to moisture such as organic EL devices and solar cells, sealing compositions are required to have barrier properties against water vapor intrusion (hereinafter sometimes referred to as “water vapor intrusion barrier properties”). Therefore, a sealing composition using hydrotalcite has been proposed. By increasing the amount of hydrotalcite in this sealing composition, the water vapor intrusion barrier property can be improved, but the adhesiveness of the sealing layer formed from the sealing composition decreases. Additionally, if the amount of hydrotalcite is increased, the influence of the interlayer water of hydrotalcite increases, and there is a problem that the amount of moisture brought by hydrotalcite into the sealing layer formed from the sealing composition increases.

On the other hand, in Non-Patent Document 1, the use of glycerin-containing hydrotalcite as a catalyst for transesterification reaction is described, but the use of glycerin-containing hydrotalcite as a moisture absorbent in a sealing composition is neither described nor suggested. .

[Patent Document 1] International Publication No. 2017/057708

[Non-patent Document 1] Clays and Clay Minerals, Vol. 58, no. 4, 475-485, 2010

The present invention has been made with attention to the above-mentioned circumstances, and its purpose is to provide a sealing composition capable of forming a sealing layer that contains less moisture and is excellent in water vapor intrusion barrier properties and adhesiveness.

As a result of extensive study, the present inventors found that the above-mentioned object could be achieved by using glycerin-containing hydrotalcite instead of conventional hydrotalcite. The present invention based on this knowledge is as follows.

[1] A sealing composition containing glycerin-containing hydrotalcite and an olefin-based polymer.

[2] The sealing composition according to [1] above, wherein the glycerin-containing hydrotalcite contains glycerin between the layers of the hydrotalcite.

[3] The sealing composition according to [1] or [2] above, wherein the amount of glycerin in the glycerin-containing hydrotalcite is 1 to 20% by mass based on the glycerin-containing hydrotalcite.

[4] The sealing composition according to any one of [1] to [3] above, wherein the olefinic polymer includes an olefinic polymer having an epoxy group and an olefinic polymer having an acid anhydride group and/or a carboxyl group.

[5] A sealing sheet having a laminated structure including a support and a sealing layer formed from the sealing composition according to any one of [1] to [4] above.

[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.

According to the present invention, it is possible to obtain a sealing composition capable of forming a sealing layer that contains less moisture and has excellent water vapor intrusion barrier properties and adhesive properties.

Sealing composition

The sealing composition of the present invention is characterized by containing glycerin-containing hydrotalcite and an olefin-based polymer. As for the components in the sealing composition of the present invention, only one type may be used, or two or more types may be used in combination. Hereinafter, each component is explained in order.

<Glycerin-containing hydrotalcite>

In this specification, “hydrotalcite” is a concept that includes hydrotalcite-like compounds such as natural hydrotalcite and synthetic hydrotalcite.

Natural hydrotalcite is a metal hydroxide with a layered crystal structure whose representative composition formula is Mg ₆ Al ₂ (OH) ₁₆ CO ₃ 4H ₂ O, and the basic skeleton layer [Mg _{1-X Al} ) ₂ ] ^X+ and the middle layer [(CO ₃ ) _X/2 ·mH ₂ O] ^X- .

Examples of hydrotalcite-like compounds include those represented by the following formula (I) and the following formula (II).

[M ²⁺ _1-x M ³⁺ _x (OH) ₂ ] ^x+ ·[(A ^n- ) _x/n ·mH ₂ O] ^x- (I)

(In the formula, M ²⁺ represents a divalent metal ion such as Mg ²⁺ or Zn ²⁺ , M ³⁺ represents a trivalent metal ion such as Al ³⁺ or Fe ³⁺ , and A ^n- is, Represents n-valent anions such as CO ₃ ^2- , Cl ^- , NO ₃ ^- , 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 CO ₃ ^2- .

M ²⁺ _x Al ₂ (OH) _2x+6-nz (A ^n- ) _z ·mH ₂ O (II)

(In the formula, M ²⁺ represents a divalent metal ion such as Mg ²⁺ or Zn ²⁺ , A ^n- represents an n-valent anion such as CO ₃ ^2- , Cl ^- , NO ₃ ^- , 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 CO ₃ ^2- .

In the present invention, a metal hydroxide having a layered crystal structure in which the amount of interlayer water is reduced or lost, obtained by calcining the above-mentioned natural hydrotalcite or a hydrotalcite-like compound, can also be used as hydrotalcite. In addition, when explained using the composition formula, “interlayer water” refers to “H ₂ O” described in the composition formula of the above-described uncalcified natural hydrotalcite and hydrotalcite-like compound.

In this specification, “glycerin-containing hydrotalcite” means hydrotalcite containing glycerin therein. As for glycerin-containing hydrotalcite, it is preferable to contain glycerin between the layers of the hydrotalcite.

The glycerin in the glycerin-containing hydrotalcite may be in an electrically neutral form (i.e., glycerin itself) or in an anionic form (i.e., a glycerolate anion formed by dissociation of a proton from glycerin).

Since glycerin-containing hydrotalcite contains glycerin inside the hydrotalcite, the amount of water (especially interlaminar water) contained therein is reduced compared to conventional hydrotalcite that does not contain glycerin. Therefore, by using glycerin-containing hydrotalcite instead of conventional hydrotalcite, moisture brought into the sealing layer can be reduced. Additionally, since glycerin itself also has hygroscopic properties, the water vapor barrier property of the sealing layer can be improved by using glycerin-containing hydrotalcite instead of conventional hydrotalcite. In addition, as will be seen from the comparison of Examples and Comparative Examples described later, by using glycerin-containing hydrotalcite instead of conventional hydrotalcite, a sealing layer with excellent adhesiveness can be formed.

The amount of glycerin in the glycerin-containing hydrotalcite is preferably lower than that of the glycerin-containing hydrotalcite (i.e., the sum of glycerin and hydrotalcite) from the viewpoint of suppressing incoming moisture and improving water vapor intrusion barrier properties and adhesion. It is 1 to 20 mass%, more preferably 1 to 15 mass%, and even more preferably 1 to 10 mass%. Additionally, by using glycerin-containing hydrotalcite with a glycerin content of 10% by mass or less, a sealing layer with a low haze value can be formed.

The particle diameter of the glycerin-containing hydrotalcite is preferably 1 to 1,500 nm, and more preferably 10 to 1,200 nm. This particle diameter is the median diameter 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).

The content of glycerin-containing hydrotalcite in the sealing composition is preferably 5 to 80% by mass, based on the non-volatile content of the sealing composition, from the viewpoint of suppressing incoming moisture and improving water vapor intrusion barrier properties and adhesion. More preferably, it is 10 to 70 mass%, and even more preferably, it is 10 to 60 mass%.

Glycerin-containing hydrotalcite may be manufactured by a known method, for example, as described in Non-Patent Document 1, and can be obtained from a manufacturer such as Kyoeisha Chemical Co., Ltd. You can use what you have.

The sealing composition may contain a hygroscopic filler other than glycerin-containing hydrotalcite (hereinafter referred to as “other hygroscopic filler”). Other hygroscopic fillers include, for example, semi-calcined hydrotalcite, calcined hydrotalcite, calcium oxide, magnesium oxide, molecular sieve, etc. As for other hygroscopic fillers, only one type may be used, or two or more types may be used in combination. The content of the other hygroscopic filler is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, further preferably 0 to 20% by mass, even more preferably, relative to the non-volatile content of the sealing composition. 0 to 10% by mass, particularly preferably 0 to 5% by mass.

<Olefin polymer>

One of the features of the present invention is that an olefin polymer is used. By using an olefin polymer, the hydrophobicity of the resulting sealing layer can be improved, and as a result, the water vapor intrusion barrier property of the sealing layer can be improved.

In this specification, “olefin-based polymer” refers to a polymer in which a structural unit derived from olefin (hereinafter sometimes abbreviated as “olefin unit”) is the main structural unit (i.e., the amount of the olefin unit is the largest among all structural units). ) refers to a polymer. In addition, hereinafter, the “structural unit derived from butene”, which is an olefin unit, may be abbreviated as “butene unit” or the like.

The olefinic polymer may be an olefinic resin (for example, propylene-butene copolymer) or an olefinic rubber (for example, butyl rubber, i.e., isobutene-isoprene copolymer). In this specification, “olefinic resin” refers to an olefinic polymer that cannot form a rubber elastomer by crosslinking, and “olefinic rubber” refers to an olefinic polymer that can form a rubber elastomer by crosslinking. do.

As the olefin, a monoolefin having one olefinic carbon-carbon double bond and/or a diolefin having two olefinic carbon-carbon double bonds are preferred. 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.

The olefin-based polymer may be a homopolymer or a copolymer. The copolymer may be a random copolymer or a block copolymer. Additionally, the olefin-based polymer may be a copolymer of an olefin and a monomer other than olefin. As olefin-based copolymers, for example, ethylene-nonconjugated diene copolymer, ethylene-propylene copolymer, ethylene-propylene-nonconjugated diene copolymer, ethylene-butene copolymer, propylene-butene copolymer, propylene-butene- Non-conjugated diene copolymer, isobutene-isoprene copolymer, styrene-isobutene copolymer, styrene-isobutene-styrene copolymer, etc.

The olefinic polymer used in the present invention preferably includes an olefinic polymer having an epoxy group and an olefinic polymer having an acid anhydride group and/or a carboxyl group. By using this combination, a crosslinked structure can be formed in the sealing layer, and as a result, a sealing layer that can suppress the decline in adhesive strength (i.e., has good moist heat resistance) even when stored under high humidity and high temperature conditions can be formed. there is. Hereinafter, the olefin-based polymer having an epoxy group and the olefin-based polymer having an acid anhydride group and/or a carboxy group will be described in order.

The content of the olefin polymer in the sealing composition is preferably 1% by mass or more, more preferably 2% by mass, relative to the non-volatile content of the sealing composition, from the viewpoint of forming a sealing layer with excellent water vapor intrusion barrier properties. or more, more preferably 3% by mass or more, particularly preferably 7% by mass or more, especially more preferably 14% by mass or more, most preferably 21% by mass or more, preferably 70% by mass or less, more preferably 70% by mass or less. In other words, it is 60% by mass or less.

The concentration of the epoxy group in the olefinic polymer having an epoxy group is preferably 0.05 to 10 mmol/g, more preferably from the viewpoint of keeping the crosslinking density of the sealing layer in a more appropriate range and achieving a balance between suppressing foam generation and adhesion. is 0.10 to 5 mmol/g. The epoxy group concentration is determined from the epoxy equivalent weight obtained based on JIS K 7236-1995.

The number average molecular weight of the olefinic polymer having an epoxy group is preferably 1,000 to 1,000,000, more preferably 2,000, from the viewpoint of keeping the fluidity of the sealing composition in a more appropriate range and suppressing the generation of bubbles and maintaining a balance between adhesion. to 800,000, more preferably 2,000 to 700,000. In addition, the number average molecular weight of each component is measured by gel permeation chromatography (GPC) method (polystyrene conversion). The number average molecular weight by GPC method is specifically, using "LC-9A/RID-6A" manufactured by Shimadzu Seisakusho as a measuring device and "Shodex K-800P/K-804L/K" manufactured by Showa Denko as a column. -804L" can be measured at a column temperature of 40°C using toluene or the like as a mobile phase and calculated using a standard polystyrene calibration curve.

The olefin-based polymer having an epoxy group is, for example, an unsaturated compound having an epoxy group (e.g., glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, allyl glycidyl ether). , can be obtained by graft modification of an olefin-based polymer under radical reaction conditions.

As the olefin polymer having an epoxy group, for example, a polymer available from Seiko PMC can be used. Examples of the polymer 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), “T-YP313” (glycidyl methacrylate modified propylene-butene random copolymer), etc.

The olefin-based polymer having an epoxy group is preferably an isobutene-isoprene copolymer (i.e., butyl rubber) having an epoxy group.

When using an isobutene-isoprene copolymer (i.e., butyl rubber) having an epoxy group as the olefin-based polymer having an epoxy group, from the viewpoint of flexibility and moisture resistance of the sealing layer, the amount of isoprene units in the copolymer is the isobutene unit. and per total of isoprene units, preferably 0.1 to 10% by mass, more preferably 0.3 to 5% by mass, and still more preferably 0.5 to 3% by mass. In addition, the amount of the isoprene unit is based on the isobutene unit and the isoprene unit excluding the modified portion (for example, the portion derived from glycidyl (meth)acrylate for introducing an epoxy group).

When using an olefin polymer having an epoxy group, its content in the sealing composition is preferably 1% by mass or more, more preferably 2% by mass, relative to the non-volatile content of the sealing composition, from the viewpoint of moisture resistance of the sealing layer. % or more, more preferably 3% by mass or more, preferably 70% by mass or less, more preferably 64% by mass or less, further preferably 60% by mass or less, particularly preferably 58% by mass or less, especially further. Preferably it is 50 mass% or less, most preferably 42 mass% or less.

Next, an olefinic polymer having an acid anhydride group (i.e., carbonyloxycarbonyl group (-CO-O-CO-)) and/or a carboxy group will be described. When an olefinic polymer having an acid anhydride group is used as an olefinic polymer having an acid anhydride group and/or a carboxy group, the concentration of the acid anhydride group in the polymer is such that the crosslinking density of the sealing layer is set to a more appropriate range and bubbles are generated. From the viewpoint of suppressing and balancing adhesion, it is preferably 0.05 to 10 mmol/g, more preferably 0.1 to 5 mmol/g. The concentration of the acid anhydride group is obtained from the value of the acid value, which is 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.

When using an olefinic polymer having a carboxyl group as an olefinic polymer having an acid anhydride group and/or a carboxyl group, the concentration of the carboxyl group in the polymer is preferably preferably is 0.1 to 20 mmol/g, more preferably 0.2 to 10 mmol/g. The concentration of the carboxylic group is obtained from the value of the acid value, which is defined as the number of mg of potassium hydroxide required to neutralize the acid present in 1 g of the polymer, according to JIS K 2501.

When an olefinic polymer having an acid anhydride group and a carboxyl group is used as an olefinic polymer having an acid anhydride group and/or a carboxyl group, the sum of the concentration of the acid anhydride group and the concentration of the carboxyl group in the polymer suppresses the generation of bubbles. From the viewpoint of achieving a balance between adhesion and adhesiveness, it is preferably 0.1 to 20 mmol/g, more preferably 0.2 to 10 mmol/g.

The number average molecular weight of the olefinic polymer having an acid anhydride group and/or a carboxyl group is preferably 1,000 to 1,000,000 from the viewpoint of keeping the fluidity of the sealing composition in a more appropriate range and suppressing the generation of bubbles and maintaining a balance between adhesion. , more preferably 2,000 to 800,000, even more preferably 2,000 to 700,000.

The olefinic polymer having an acid anhydride group and/or a carboxyl group is preferably an isobutene-isoprene copolymer (i.e., butyl rubber) having an acid anhydride group and/or a carboxyl group, and/or an acid anhydride group and/or a carboxyl group. It is a polybutene having an acid anhydride 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 polypolymer having an acid anhydride group. It's buten.

When using isobutene-isoprene copolymer (i.e., butyl rubber) having an acid anhydride group and/or a carboxy group (preferably an acid anhydride group) as the olefinic polymer having an acid anhydride group and/or a carboxy group, the sealing layer From the viewpoint of flexibility and moisture resistance, the amount of isoprene units in the copolymer is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, per the total of isobutene units and isoprene units. In addition, the amount of the isoprene unit is the isoprene unit excluding the modified portion (e.g., a portion derived from maleic anhydride for introducing an acid anhydride group, a portion derived from maleic anhydride-(meth)acrylate copolymer, etc.) Based on ten units and isoprene units.

The olefinic polymer having an acid anhydride group and/or a carboxyl group is, for example, an unsaturated compound having an acid anhydride group and/or a carboxyl group (e.g., maleic anhydride), and the olefinic polymer is graft-modified under radical reaction conditions. It can be manufactured by doing this.

As the olefin-based 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), and "ER661" manufactured by Seiko PMC. 」(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), “ER688” (maleic anhydride-butyl methacrylate random copolymer modified polybutene); “HV-300M” (maleic anhydride-modified liquid polybutene) manufactured by Toho Chemical Co., Ltd.; “Lucant A-5515” (acid-modified ethylene-α-olefin copolymer) manufactured by Mitsui Chemicals Co., Ltd., “Lucant A-5260” (acid-modified ethylene-α-olefin copolymer), “Lucant A-5320H” (acid-modified ethylene-α-olefin copolymer), and the like.

When using an olefinic polymer having an acid anhydride group and/or a carboxyl group, its content in the sealing composition is preferably 1% by mass or more relative to the non-volatile content of the sealing composition from the viewpoint of moisture resistance of the sealing layer. , more preferably 2% by mass or more, further preferably 3% by mass or more, preferably 70% by mass or less, more preferably 64% by mass or less, further preferably 60% by mass or less, especially preferably It is 58 mass% or less, particularly preferably 50 mass% or less, and most preferably 42 mass% or less.

When using an olefinic polymer having an epoxy group and an olefinic polymer having an acid anhydride group and/or a carboxy group, “amount of epoxy group (mol) possessed by the olefinic polymer having an epoxy group”: “acid anhydride group and/or carboxy group” The sum of the amount (mol) of acid anhydride groups and the amount (mol) of carboxyl groups possessed by the olefinic polymer having a 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. Also, for example, when the olefinic polymer having an acid anhydride group and/or a carboxyl group has only an acid anhydride group, the above “sum of the amount (mol) of the acid anhydride group and the amount (mol) of the carboxyl group” is “acid It means “amount (mol) of anhydride group.”

When using isobutene-isoprene copolymer (i.e., butyl rubber) as the olefinic polymer, from the viewpoint of adhesion at low and high temperatures and flexibility, the amount of isobutene-isoprene copolymer in the olefinic polymer is Relative to this, it is preferably 50 to 95 mass%, more preferably 50 to 90 mass%, and even more preferably 55 to 85 mass%. Additionally, the isobutene-isoprene copolymer may have a functional group (for example, an epoxy group, an acid anhydride group, and/or a carboxy group).

In order to provide good adhesion and flexibility to the sealing layer, the olefin-based polymer used in the present invention is preferably a liquid olefin-based polymer (hereinafter simply referred to as “liquid olefin”) that does not have any of an epoxy group, an acid anhydride group, or a carboxyl group. (sometimes described as “unmodified liquid olefin polymer” or “unmodified liquid olefin polymer”). In this specification, “liquid phase” in “liquid olefin polymer” means that the viscosity at 25°C is 5,000 Pa·s or less. In addition, in the present invention, “viscosity at 25°C” means the viscosity calculated by multiplying the kinematic viscosity at 25°C measured with a dynamic viscoelasticity measuring device by the density. Examples of the dynamic viscoelasticity measuring device include a rheometer (brand name: DISCOVERY HR-2) manufactured by TA Instruments.

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 from the viewpoint of adhesion and tack provision of the sealing layer. Typically, it is 200 to 3,000 Pa·s.

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 still more preferably 300 to 20,000.

As the unmodified liquid olefin polymer, a polymer available from a manufacturer can be used. Examples of such polymers include "HV-300" (liquid polybutene), "HV-1900" (liquid polybutene), "HV-50" (liquid polybutene), and "HV-35" (manufactured by ENEOS) liquid polybutene); “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; “200N” manufactured by Nichiyu Corporation (liquid polybutene); “BI-2000” (hydrogenated polybutadiene), “BI-3000” (hydrogenated polybutadiene), “GI-3000” (hydrogenated polybutadiene), “B-1000” (liquid polybutadiene), “B” manufactured by Nihon Soda Corporation. -3000” (liquid polybutadiene), “G-3000” (liquid polybutadiene; “Lucant LX100” (liquid olefin-based polymer) manufactured by Mitsui Chemicals, “Lucant LX400” (liquid olefin-based polymer); Idemitsu Showa "Poly bd R-45HT" (butadiene-based liquid rubber), "Poly bd R-15HT" (butadiene-based liquid rubber), and "Poly ip" (liquid polyisoprene) manufactured by Shell; "LIR-30" (liquid) manufactured by Kuraray Co., Ltd. polyisoprene), “LIR-390” (liquid polyisoprene), “LIR-290” (liquid polyisoprene), “LBR-302” (liquid polybutadiene), “LBR-305” (liquid polybutadiene), “LBR -361" (liquid polybutadiene), "L-SBR-820" (liquid styrene-butadiene random copolymer); "Ricon 154" (liquid butadiene) manufactured by CRAY VALLEY, "RICON 184" (liquid styrene-butadiene random copolymer) coalescence); etc.

The unmodified liquid olefin polymer is preferably liquid polybutene.

When using an unmodified liquid olefin polymer, its content in the sealing composition is preferably 5 to 50% by mass, based on the non-volatile content of the sealing composition, from the viewpoint of the adhesiveness and flexibility of the sealing layer. Preferably it is 10 to 45 mass%, more preferably 15 to 40 mass%.

<Other ingredients>

The sealing composition of the present invention may contain components other than glycerin-containing hydrotalcite and olefin-based polymerization (hereinafter sometimes referred to as “other components”) to the extent that the effect of the present invention is not impaired. . Other components include, for example, a tackifier, a curing accelerator, and an antioxidant. These may be used alone or in combination of two or more. Hereinafter, these will be explained in order.

(Tackifier)

A tackifier is a component that provides adhesion to the sealing composition. As a tackifier, for example, rosin-based resin, terpene resin, modified terpene resin (hydrogenated terpene resin, terpene phenol copolymer resin, aromatic modified terpene resin, etc.), petroleum resin (aliphatic petroleum resin, hydrogenated petroleum resin, etc.) alicyclic petroleum resin, aromatic petroleum resin, copolymerized petroleum resin), coumarone-indene resin, alkylphenol resin, xylene resin, etc.

A commercially available tackifier can be used. Examples of commercial products include the following. Rosin-based resins include, for example, Fine Crystal ME-H, Fine Crystal ME-D, Fine Crystal ME-G, Fine Crystal KR-85, Fine Crystal KE-311, Fine Crystal KE-359, and Fine Crystal D-6011. , Fine Crystal PE-590, Fine Crystal KE-604, and Fine Crystal PR-580 (all manufactured by Arakawa Chemical Co., Ltd.).

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.). You can.

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

Examples of the terpene phenol copolymer resin include YS Polyster 2000, Polyster U, Polyster T, Polyster S, and Mighty Ace G (all manufactured by Yasuhara Chemical Co., Ltd.).

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

Hydrogenated petroleum resins include, for example, Escorez 5300 series and 5600 series (all manufactured by Exxon Mobil); 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 (all manufactured by Nihon Zeon Corporation); iMav S-100, iMARV S-110, iMARV P-100, iMARV P-125, iMARV P-140 (all hydrogenated dicyclopentadiene-based petroleum resins, manufactured by Idemitsu Kosan Corporation); 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 Kagaku Kogyo), etc.

Examples of the aromatic petroleum resin include ENDEX155 (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 Corporation); Examples include T-REZ RB093, T-REZ RC100, T-REZ RC115, T-REZ RC093, and T-REZ RE100 (all manufactured by ENEOS).

Examples of the copolymerized petroleum resin include T-REZ HB103, T-REZ HB125, T-REZ PR801, T-REZ PR802, and T-REZ RD104 (all manufactured by ENEOS); Petrotac 60, Petrotac 70, Petrotac 90, Petrotac 90HS, Petrotac 90V, Petrotac 100V (all manufactured by Tosoh); Quintone D100 (manufactured by Nippon Zeon Corporation), etc. can be mentioned.

The softening point of the tackifier is preferably 50 to 200°C, more preferably 90 to 180°C, and even more preferably 100 to 150°C from the viewpoint of heat resistance of the sealing composition, etc. In addition, the softening point is measured by the ring and ball method according to JIS K2207.

When using a tackifier, its content in the sealing composition is preferably 1 to 50% by mass, more preferably 5 to 45% by mass, and still more preferably 10 to 10% by mass, based on the non-volatile content of the sealing composition. It is 40% by mass.

(curing accelerator)

A curing accelerator may be used to promote the crosslinking reaction between the epoxy group of the olefin-based polymer having an epoxy group and the acid anhydride group and/or carboxy group of the olefin-based polymer having an acid anhydride group and/or carboxyl group. Examples of the curing accelerator include imidazole compounds, tertiary and quaternary amine compounds, dimethyl urea compounds, and organic phosphine compounds.

Examples of imidazole compounds include 1H-imidazole, 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, and 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-dodecyl Midazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, etc. are mentioned. Specific examples of imidazole compounds include Cursol 2MZ, 2P4MZ, 2E4MZ, 2E4MZ-CN, C11Z, C11Z-CN, C11Z-CNS, C11Z-A, 2PHZ, 1B2MZ, 1B2PZ, 2PZ, C17Z, 1.2DMZ, 2P4MHZ-PW, Examples include 2MZ-A and 2MA-OK (all manufactured by Shikoku Kasei Kogyo Corporation).

There are no particular restrictions on the tertiary or quaternary amine compounds, and examples include quaternary ammonium salts such as tetramethylammonium bromide, tetrabutylammonium bromide, and triethylmethylammonium/2-ethylhexanoate; DBU (1,8-diazabicyclo[5.4.0]undecene-7), DBN (1,5-diazabicyclo[4.3.0]nonene-5), DBU-phenol salt, DBU-octylate, DBU -diazabicyclo compounds such as p-toluenesulfonate, DBU-formate, and DBU-phenol novolak resin salt; Tertiary amines or salts thereof such as benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol (TAP), dimethylurea such as aromatic dimethylurea and aliphatic dimethylurea compound; etc. can be mentioned.

Examples of dimethyl urea compounds include aromatic dimethyl ureas such as DCMU (3-(3,4-dichlorophenyl)-1,1-dimethyl urea) and U-CAT3512T (manufactured by San-Apro); Aliphatic dimethyl ureas such as U-CAT3503N (manufactured by San-Apro), etc. can be mentioned. Among them, aromatic dimethyl urea is preferably used in terms of curability.

Examples of organic phosphine compounds include triphenylphosphine, tetraphenylphosphonium tetra-p-tolyl borate, tetraphenylphosphonium tetraphenyl borate, tri-tert-butylphosphonium tetraphenyl borate, (4-methylphenyl) ) Triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, triphenylphosphinetriphenylborane, etc. Specific examples of organic phosphine compounds include TPP, TPP-MK, TPP-K, TTBuP-K, TPP-SCN, and TPP-S (all manufactured by Hoko Chemical Co., Ltd.).

When using a curing accelerator, its content in the sealing composition is not particularly limited as long as the crosslinking reaction is promoted in order to promote the above-mentioned crosslinking reaction, but is preferably 0.005 to 1% by mass relative to the non-volatile content of the sealing composition. , more preferably 0.010 to 0.5 mass%, even more preferably 0.015 to 0.25 mass%.

(antioxidant)

There is no particular limitation to the antioxidant in the present invention, and known antioxidants can be used.

Sealing sheet

The present invention also provides a sealing sheet having a laminated structure including a support and a sealing layer formed from the sealing composition of the present invention. A protective sheet may be used in the present invention. That is, the sealing 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 (for example, a release layer) may exist between the support and the sealing layer, and between the sealing layer and the protective sheet.

Examples of the support and protective sheet include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; cycloolefin polymer; Polyesters such as polyethylene terephthalate (hereinafter sometimes referred to as “PET”) and polyethylene naphthalate; polycarbonate; Plastic films, such as polyimide, etc. are mentioned. The support and the protective sheet may both be single-layer films or laminated films.

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

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

The thickness of the support and the protective sheet are not particularly limited, but are each preferably 10 to 150 μm, more preferably 20 to 100 μm, from the viewpoint of handling of the sealing sheet and the like. In addition, when the support and the protective sheet are laminated films, the above thickness is the thickness of the laminated film. On the other hand, the thickness of the sealing layer is preferably 1 to 200 μm, more preferably 3 to 150 μm, and even more preferably 5 to 5 μm from the viewpoint of embedding and water vapor barrier performance when laminated to a substrate with irregularities. It is 100㎛. If the thickness of the sealing layer is 1 μm or more, the sealing layer can better follow the irregularities and improve embedding properties. If the thickness of the sealing layer is 200 μm or less, water vapor intrusion from the end face of the sealing layer can be better suppressed, and water vapor barrier performance can be improved.

The sealing layer in the sealing sheet preferably has transparency, 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 Typically, it is less than 5%. The haze value of the sealing layer with 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 according to JIS K 7136.

Preparation of sealing compositions and sealing sheets

The sealing composition of the present invention can be produced by mixing the above-mentioned components using a known device.

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

Organic solvents that can be used to prepare varnishes include, for example, ketones such as acetone, methyl ethyl ketone, and cyclohexanone; Acetic acid 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; etc. can be mentioned. Only one type of organic solvent may be used, or two or more types may be used in combination. As an organic solvent, a commercially available product may be used. Examples of the commercially available products include "Suwasol" manufactured by Maruzen Sekiyu Kagaku Corporation and "Ipsol" manufactured by Idemitsu Kosan Corporation. The application of the varnish may be performed by a known method (for example, a method using a die coater), and there is no particular limitation on the application method.

In order to proceed with the reaction between the epoxy group of the olefinic polymer having an epoxy group and the acid anhydride group and/or carboxyl group of the olefinic polymer having an acid anhydride group and/or carboxyl group, removal of the organic solvent is performed by heating the coating film. It is desirable. The heating temperature of the coating film is preferably 80 to 200°C, more preferably 100 to 180°C, and the time is preferably 2 to 90 minutes, more preferably 5 to 60 minutes. Heating of the coating film may be performed under normal pressure or under reduced pressure.

Use of sealing compositions and sealing sheets

The sealing composition and sealing sheet of the present invention can be used for sealing 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), substrates using silver nanowires (AgNWs), and the like.

[Example]

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, and may be implemented with appropriate changes within the scope suitable for the above and below purposes. Of course, it is possible, and these are all included in the technical scope of the present invention.

In addition, unless otherwise specified, such as reflectance, transmittance, haze value, etc., “%” and “part” below mean “% by mass” and “part by mass,” respectively.

<Ingredients>

The components used in the examples and comparative examples are shown below.

(1) Olefin polymer

“ER866” (manufactured by Seiko PMC, 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, 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: 98.9%/1.1%)

“HV-300M” (manufactured by Toho Kagaku Kogyo Co., Ltd., maleic anhydride-modified liquid polybutene, acid anhydride group concentration: 0.77 mmol/g, number average molecular weight: 2,100)

“HV-1900” (manufactured by ENEOS, liquid polybutene, number average molecular weight: 2,900, viscosity at 25°C: 460 Pa·s)

(2) Hydrotalcite or glycerin-containing hydrotalcite

“DHT-4C” (manufactured by Kyowa Chemical Kogyo Co., Ltd., hydrotalcite not containing glycerin, median diameter: 400 nm, hereinafter referred to as “hydrotalcite”)

“Barrier site W-3” (manufactured by Kyoeisha Chemical Co., Ltd., hydrotalcite containing 3% glycerin, median diameter: 700 nm, hereinafter referred to as “HT-Gly 3%”)

“Barrier site W-5” (manufactured by Kyoeisha Chemical Co., Ltd., hydrotalcite containing 5% glycerin, median diameter: 800 nm, hereinafter referred to as “HT-Gly 5%”)

“Barrier site W-15” (manufactured by Kyoeisha Chemical Co., Ltd., hydrotalcite containing 15% glycerin, median diameter: 800 nm, hereinafter referred to as “HT-Gly 15%”)

(3) Tackifier

“Alcon P125” (manufactured by Arakawa Chemical Co., Ltd., cyclohexane ring-containing saturated hydrocarbon resin)

(4) Curing accelerator

2,4,6-Tris(dimethylaminomethyl)phenol (manufactured by Kayaku Nurion, hereinafter referred to as “TAP”)

<Example 1>

A varnish with a mixing ratio shown in the table below was produced in the following procedure, and a sealing sheet was produced using the obtained varnish. In addition, the usage amount (part) of each component listed in the table below represents the amount of non-volatile matter of each component in the varnish.

Specifically, a swazole solution (non-volatile matter: 60%) of a tackifier (Alcon P125), maleic anhydride-modified liquid polybutene (HV-300M), liquid polybutene (HV-1900), and glycerin-containing hydrotal were added. Site (HT-Gly 3%) was dispersed with 3 rolls to obtain a mixture. To the obtained mixture, a toluene solution of glycidyl methacrylate modified butyl rubber (ER866) (non-volatile content: 40%) and a toluene solution of maleic anhydride-butyl methacrylate random copolymer modified butyl rubber (ER661) (non-volatile content) : 40%), a curing accelerator (TAP), and toluene were mixed, and the resulting mixture was uniformly dispersed with a high-speed rotating mixer to obtain a varnish of a sealing composition. The obtained varnish was uniformly applied with a die coater onto the release-treated surface of a polyethylene terephthalate (PET) film "SP4020" (PET: 50 μm: manufactured by Toyo Cross Co., Ltd.) treated with a silicone-based release agent, and heated at 130°C for 30 minutes. And then, by heating at 160°C for 30 minutes, a sealing sheet having a sealing layer with a thickness of 50 μm was obtained.

<Example 2>

A sealing sheet having a varnish of the sealing composition and a sealing layer with a thickness of 50 μm was produced in the same manner as in Example 1, except that HT-Gly 5% was used instead of HT-Gly 3%.

<Example 3>

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

<Comparative Example 1>

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

For the sealing layer of each sealing sheet obtained in the Examples and Comparative Examples, the incoming moisture was measured based on the moisture content, the water vapor intrusion barrier property was measured by the "Ca test [time/2mm]" described later, and the aluminum foil or barrier layer. The adhesion to each was evaluated by 90 degree peel strength. The results are shown in Table 1.

<Incoming water>

The sealing sheet produced in Examples and Comparative Examples was cut to 70 mm in length and 40 mm in width, folded into a well-dried screw vial bottle (VABH17, manufactured by Mitsubishi Chemical Analytech), and measured with a Cull Fisher measuring instrument (CA310 type, Mitsubishi Chemical Analytech). It was placed in an electric furnace (VA-236S type, manufactured by Mitsubishi Chemical Analytech) directly connected to the furnace. In the N ₂ airflow, the temperature of the electric furnace was raised to 250°C, the water detached from the measurement sample was collected in Karl Fischer measurement liquid, and the mass of water was measured by the regular 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.

<Water vapor intrusion barrier property>

As a support film, a composite film "PET Tsuki AL1N30" comprising an aluminum foil and a polyethylene terephthalate film (aluminum foil thickness 30 μm, polyethylene terephthalate film thickness 25 μm, manufactured by Tokai Toyo Aluminum Hanbai Co., Ltd.) was prepared. Except that this support film was used instead of the PET film, a sealing layer was formed on the surface of the support film on the aluminum foil side in the same manner as the manufacturing method of the sealing sheet in each Example and Comparative Example. As a result, a test sheet including a support film and a sealing layer was obtained.

A glass plate measuring 50 mm x 50 mm made of alkali-free glass was prepared. This glass plate was washed with boiled isopropyl alcohol for 5 minutes and dried at 150°C for more than 30 minutes.

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

In a nitrogen atmosphere, the sealing layer of the test sheet described above and the calcium film side surface of the glass plate were bonded together using a thermal laminator (Lamy Packer DAiSY A4 (LPD2325) manufactured by Fujipla) to prepare a laminate evaluation sample. got it

Generally, when calcium comes into contact with water and becomes calcium oxide, it becomes transparent. In addition, in the above evaluation sample, since the glass plate and the aluminum foil have sufficiently high water vapor intrusion barrier properties, moisture usually moves in the in-plane direction (direction perpendicular to the thickness direction) through the end of the sealant layer, thereby forming the calcium film. can be reached. Therefore, when moisture enters the evaluation sample, the calcium film is gradually oxidized from the end and becomes transparent, so shrinkage of the calcium film is observed. Therefore, moisture intrusion into the evaluation sample can be evaluated by measuring the sealing distance [mm] from the end of the evaluation sample to the calcium film. Therefore, an evaluation sample containing a calcium film can be used as a model for an electronic device.

First, the sealing distance X2 [mm] from the end of the evaluation sample to the end of the calcium film was measured using a microscope (Measuring Microscope MF-U, manufactured by Mitsutoyo Corporation). Hereinafter, this sealing distance X2 is described as the original sealing distance X2.

Next, the evaluation sample was stored in a constant temperature and humidity chamber set at a temperature of 85°C and a humidity of 85%RH. The evaluation sample was taken out from the constant temperature and humidity chamber when the sealing distance The time from when the evaluation sample was stored in the constant temperature and humidity chamber to the time when the evaluation sample was taken out from the constant temperature and humidity chamber was determined as the decrease start time t [time]. This reduction start time t is from the point in time TP1 when the evaluation sample was stored in the constant temperature and humidity chamber, when the sealing distance X1 [mm] between the end of the evaluation sample stored in the constant temperature and humidity chamber and the end of the calcium film becomes " Equivalent to the time until TP2.

The above-mentioned sealing distance

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

<Adhesion to aluminum foil>

In Examples and Comparative Examples, a sealing sheet (length 50 mm, width 20 mm) using PET film as a support was laminated with aluminum foil and polyethylene terephthalate film using a batch vacuum laminator (Morton-724, manufactured by Nichigo Morton Co., Ltd.). It was laminated on the composite film "PET Tsuki AL1N30" (aluminum foil thickness: 30 μm, PET film thickness: 25 μm, manufactured by Tokai Toyo Aluminum Hanbai Co., Ltd.). Lamination was performed at a temperature of 80°C, time of 30 seconds, and pressure of 0.3 MPa. Then, the PET film was peeled off, and an additional glass plate (length 76 mm, width 26 mm, thickness 1.2 mm, micro slide glass) was laminated on the exposed sealing layer under the same conditions as above. About the obtained laminated body, the 90-degree peeling strength when peeled in the 90-degree direction with respect to the longitudinal direction of the aluminum foil at a tensile speed of 50 mm/min was measured.

<Adhesion to barrier layer>

"PET Tsuki AL1N30" used in the above <Adhesion to aluminum foil> was replaced with "Bereal 38U001", a high-performance film comprising a barrier layer on a PET film (barrier layer: a layer made of SiOC formed by the plasma CVD method, barrier layer The 90 degree peeling strength was measured in the same manner except that the thickness of the PET film was changed to 0.5 μm and the thickness of the PET film was 38 μm, manufactured by Rayco.

<Measurement of haze value>

The sealing sheet produced in the example was cut to a length of 50 mm and a width of 20 mm, and the cut sealing sheet was placed on a glass plate (76 mm in length, 26 mm in width, and 1.2 mm in thickness, using micro slide glass (Matsunami Glass Kogyo Co., Ltd., Back Slide Glass S1112). A batch vacuum laminator (V-160, manufactured by Nichigo Morton Co., Ltd.) was used for polishing No. 2), and the sealing layer was laminated so that the glass plate was in contact. The lamination conditions were a temperature of 80° C., a pressure reduction time of 30 seconds, and a pressure of 80° C. Pressure was applied at 0.3 MPa for 30 seconds. Afterwards, 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 optic with a ϕ60 mm integrating sphere (model name SRS-99-010, reflectance 99%). Measured using a spectrophotometer (MCPD-7700, model 311C, manufactured by Otsuka Electronics, external light source unit: halogen lamp MC-2564 (24V, 150W specification)), total light transmittance (%) and diffuse transmittance at a wavelength of 450 nm (%) was calculated, and the haze value was calculated. In addition, the distance between the integrating sphere and the sample (laminated body) was set to 0 mm, and glass was used as a reference. The haze value of the sealing layer of Example 1 was 2.7%, and 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%, and it was confirmed that a transparent sealing layer was obtained in Examples 1 to 3.

As shown in Table 1, compared to the sealing layer obtained in Comparative Example 1 using hydrotalcite, the sealing layer obtained in Examples 1 to 3 using glycerin-containing hydrotalcite had less moisture brought in, and further prevented water vapor intrusion. It has excellent barrier properties, adhesion to aluminum foil, and adhesion to barrier layers.

The sealing composition and sealing sheet of the present invention are useful for sealing electronic devices.

This application is based on Japanese Patent Application No. 2022-042689, the contents of which are fully included in the specification of this application.

Claims (7)

A sealing composition comprising glycerin-containing hydrotalcite and an olefin-based polymer. The sealing composition according to claim 1, wherein the glycerin-containing hydrotalcite contains glycerin between layers of the hydrotalcite. The sealing composition according to claim 1 or 2, wherein the amount of glycerin in the glycerin-containing hydrotalcite is 1 to 20% by mass based on the glycerin-containing hydrotalcite. The sealing composition according to claim 1 or 2, wherein the olefinic polymer includes an olefinic polymer having an epoxy group and an olefinic polymer having an acid anhydride group and/or a carboxyl group. A sealing sheet having a laminated structure comprising a support and a sealing layer formed from the sealing composition according to claim 1 or 2. An electronic device comprising a sealing layer formed from the sealing composition according to claim 1 or 2. A conductive substrate comprising a sealing layer formed from the sealing composition according to claim 1 or 2.