JP2024002041A - Desiccant composition, alkoxysilane compound and organic el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the unexpected hydrolysis of a metal alkoxide compound for ensuring sufficient water capturing property in an organic EL element.

SOLUTION: In a desiccant composition including a water capturing component and an acid generating agent, the water capturing component includes an alkoxysilane compound expressed by the formula: Si(OR¹)_n(R²)_4-n (where, n is an integer of 1-4; R¹ is a monovalent organic group including a carbon atom bonded to an oxygen atom bonded to Si; R² is an alkyl group which may have a substituent group or an aryl group which may have a substituent group; a plurality of R¹s and R²s in the same molecule may be the same or different; and at least one selected from among R¹ and R² in the same molecule is a group including a 4-membered ring cyclic ether group or a 5-membered ring cyclic ether group).

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a desiccant composition, an alkoxysilane compound, and an organic EL device.

A metal alkoxide compound having a central atom selected from an aluminum atom, a titanium atom, a silicon atom, and a boron atom is sometimes used as a water-trapping component of a desiccant composition for an organic EL device, etc. (Patent Document 1) . The metal alkoxide compound can function as a water-trapping component through a hydrolysis reaction.

JP 2016-138068 Publication

Before a desiccant composition containing a metal alkoxide compound is used for manufacturing an organic EL element, hydrolysis of the metal alkoxide compound may proceed due to atmospheric moisture or the like. In order to ensure sufficient water-trapping performance in an organic EL element, it is desirable that unintended hydrolysis of the metal alkoxide compound be suppressed.

The present disclosure generally includes the following measures.
[1] A desiccant composition containing a water-capturing component and an acid generator. The water-trapping component includes an alkoxysilane compound represented by the formula: Si(OR ¹ ) _n (R ² ) _4-n . n represents an integer from 1 to 4. R ¹ represents a monovalent organic group containing a carbon atom bonded to an oxygen atom bonded to Si. R ² represents an alkyl group which may have a substituent or an aryl group which may have a substituent. A plurality of R ¹ and R ² in the same molecule may be the same or different. At least one selected from R ¹ and R ² in the same molecule is a group containing a 4-membered cyclic ether group or a group containing a 5-membered cyclic ether group.
[2] The group containing the 4-membered cyclic ether group has the following formula (1):

A group represented by the following formula (2):

The desiccant composition according to [1], wherein m is an integer of 0 to 5, and R ¹⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
[3] The desiccant composition according to [1] or [2], further comprising an epoxy resin.
[4] Formula: Si(OR ¹ ) _n (R ² ) _4−n , where n represents an integer of 1 to 4, and R ¹ is the following formula (A):

A group represented by R ² represents an alkyl group that may have a substituent or an aryl group that may have a substituent, and multiple R ² in the same molecule are the same. However, the alkoxysilane compound may be different.
[5] It has an element substrate, a sealing substrate disposed opposite to the element substrate, a pair of electrodes disposed opposite to each other provided on the element substrate, and an organic layer provided between them. A light-emitting portion, and a sealing layer provided between the element substrate and the sealing substrate to seal the light-emitting portion, wherein the sealing layer is any one of [1] to [3]. An organic EL device comprising a cured product of the desiccant composition described in .
[6] The sealing layer fills a space around the light emitting part between the element substrate and the sealing substrate while being in contact with the element substrate and the sealing substrate. organic EL element.
[7] The organic EL element further includes an encapsulating sealant that seals the outer periphery of the element substrate and the sealing substrate, and the sealing layer is arranged around the light emitting part inside the encapsulating sealant. The organic EL element according to [5], which fills at least a part of the airtight space.
[8] The organic EL device according to [5], wherein the sealing layer has a laminated structure including a cured film containing a cured product of the desiccant composition and an inorganic film.

An alkoxysilane compound in which unintended hydrolysis is suppressed, and a desiccant composition containing the same are provided.

FIG. 1 is a cross-sectional view showing one embodiment of an organic EL element. FIG. 1 is a cross-sectional view showing one embodiment of an organic EL element. FIG. 1 is a cross-sectional view showing one embodiment of an organic EL element. FIG. 1 is a cross-sectional view showing one embodiment of an organic EL element. It is a graph showing the relationship between water capture capacity and standing time. It is a graph showing the relationship between water capture capacity and standing time. It is a graph showing the relationship between water capture capacity and standing time.

The invention is not limited to the following examples.

An example of a desiccant composition includes a water-trapping component and an acid generator. The desiccant composition can be used, for example, as a sealant for organic EL. The desiccant composition may further include an epoxy resin.

The water-trapping component includes an alkoxysilane compound represented by the formula: Si(OR ¹ ) _n (R ² ) _4-n . n represents an integer from 1 to 4. R ¹ represents a monovalent organic group containing a carbon atom bonded to an oxygen atom bonded to Si. R ² represents an alkyl group which may have a substituent or an aryl group which may have a substituent. A plurality of R ¹ and R ² in the same molecule may be the same or different. At least one of R ¹ and R ² in the same molecule is a group containing a 4-membered cyclic ether group or a group containing a 5-membered cyclic ether group. Alkoxysilane compounds having a group containing a 4-membered or 5-membered cyclic ether group are difficult to undergo unintended hydrolysis. Moreover, a 4-membered or 5-membered cyclic ether group is difficult to cause a polymerization reaction even under alkaline conditions. In this respect, alkoxysilane compounds having a group containing a 4- or 5-membered cyclic ether group are advantageous compared to alkoxysilane compounds having an epoxy group, which are relatively easy to polymerize under alkaline conditions. By inhibiting polymerization, the storage stability (for example, viscosity stability) of the desiccant composition can be further improved.

n may be 2, 3 or 4, or may be 3 or 4. When n is 3, unintended hydrolysis can be suppressed even more effectively while maintaining good water-capturing performance. From the viewpoint of high water-capturing performance, n may be 4.

In the alkoxysilane compound, R ¹ , R ² or both may be a group containing a 4-membered cyclic ether group or a group containing a 5-membered cyclic ether group. When the desiccant composition contains an epoxy resin, the 4- or 5-membered cyclic ether group can react with the epoxy group by cationic polymerization. By reaction with epoxy groups, alkoxysilane compounds can be bonded to the epoxy resin polymer. As a result, the generation of outgas containing alcohol produced by hydrolysis of the alkoxysilane compound can be suppressed.

R ¹ may be a group containing a 4-membered cyclic ether group or a group containing a 5-membered cyclic ether group. The number of 4-membered or 5-membered cyclic ether groups contained in the alkoxysilane compound may be 1 to 4, 2 to 4, 3, or 4.

The group containing a 4-membered cyclic ether group is, for example, the following formula (1):

It may be a group represented by

The group containing a 5-membered cyclic ether group is, for example, the following formula (2):

It may be a group represented by

In formulas (1) and (2), m represents an integer of 0 to 5, and R ¹⁰ represents a hydrogen atom or an alkyl group. R ¹⁰ may be an alkyl group having 1 to 5 carbon atoms. m may be 1-5, 1-4, 1-3, 1-2 or 1. In formulas (1) and (2), -(CH ₂ ) _m - and R ¹⁰ are arbitrary groups constituting a 4-membered cyclic ether group (oxetane ring) or a 5-membered cyclic ether group (tetrahydrofuran ring). is a group that bonds to the carbon atom of

The group represented by formula (1) or (2) may be a group represented by formula (1A) or (2A) below.

In the alkoxysilane compound represented by the formula: Si(OR ¹ ) _n (R ² ) _4-n , at least one R ¹ is represented by the following formula (A):

It may be a group represented by

The content of the alkoxysilane compound represented by the formula: Si(OR ¹ ) _n (R ² ) _4-n in the desiccant composition is, for example, 0.1 to 90% by mass based on the mass of the desiccant composition. It may be %. The content of the alkoxysilane compound may be 1% by mass or more, 2% by mass or more, 3% by mass or more, 4% by mass or more, or 5% by mass or more, based on the mass of the desiccant composition, and may be 100% by mass or more. % or less, 95% by mass or less, 85% by mass or less, 80% by mass or less, 75% by mass or less, 70% by mass or less, 65% by mass or less, 60% by mass or less, 55% by mass or less, 50% by mass or less, 45% by mass % or less, 40% by mass or less, 35% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, or 15% by mass or less.

When R ¹ is not a group containing a 4-membered cyclic ether group or a group containing a 5-membered cyclic ether group, R ¹ is, for example, an alkyl group having 1 to 5 carbon atoms which may have a substituent. or an aryl group (for example, a phenyl group) which may have a substituent. The substituent in this case is a group that does not contain a 4-membered or 5-membered cyclic ether group, and examples thereof are the same as the examples of substituents that the alkyl group or aryl group as R ² may have. .

R ² may be an alkyl group or an aryl group substituted with a 4- or 5-membered cyclic ether group, or an alkyl group or an aryl group having other substituents, or an unsubstituted alkyl group or an aryl group. It may be an alkyl group or an unsubstituted aryl group. The number of carbon atoms in the alkyl group as R ² may be, for example, 1 to 10, 1 to 9, 1 to 8, or 1 to 6. R ² may be a phenyl group. Examples of substituents that the alkyl group or aryl group as R ² may have include a halogeno group, an alkoxy group, a vinyl group, and a (meth)acrylic group.

The epoxy resin may be a compound having two or more epoxy groups, such as bisphenol A epoxy resins such as 2,2-bis(4-glycidyloxyphenyl)propane (or bisphenol A diglycidyl ether). ), bisphenol F type epoxy resins (eg, bis[4-(glycidyloxy)phenyl]methane), and epoxy-modified silicones.

The content of the epoxy resin is, for example, 1% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, based on the mass of the desiccant composition. mass% or more, 40 mass% or more, 45 mass% or more, 50 mass% or more, 55 mass% or more, 60 mass% or more, 65 mass% or more, 70 mass% or more, 75 mass% or more, 80 mass% or more, or It may be 85% by mass or more, 99.9% by mass or less, 99% by mass or less, 98% by mass or less, 97% by mass or less, 96% by mass or less, or 95% by mass or less.

The acid generator can be, for example, a photoacid generator or a thermal acid generator. The photoacid generator may be, for example, a triarylsulfonium salt. The content of the acid generator may be, for example, 0.1 to 10% by mass based on the mass of the desiccant composition.

The total content of the alkoxysilane compound and acid generator in the desiccant composition is, for example, 1% by mass or more, 5% by mass or more, 10% by mass or more, 30% by mass or more, 50% by mass or more based on the mass of the desiccant composition. It may be at least 60% by mass, at least 70% by mass, at least 80% by mass, or at least 90% by mass, and may be at most 100% by mass or at most 99.9% by mass. When the desiccant composition further contains an epoxy resin, the total content of the alkoxysilane compound, acid generator, and epoxy resin is, for example, 50% by mass or more, 60% by mass or more, 70% by mass based on the mass of the desiccant composition. The content may be greater than or equal to 80% by mass, or greater than or equal to 90% by mass, and may be less than or equal to 100% by mass or less than 99.9% by mass. The desiccant composition may further contain other components such as a curing reaction retarder.

1, 2, 3, and 4 are cross-sectional views showing examples of organic EL devices each having a desiccant layer formed from the desiccant composition exemplified above.

The organic EL device 1A shown in FIG. It has a sealant 8 that seals between the outer peripheral part and the element substrate 2, and a desiccant layer 7 provided between the element substrate 2 and the sealing substrate 3. Desiccant layer 7 contains a cured product of the desiccant composition described above. The desiccant layer 7 illustrated in FIG. 1 is filled in the airtight space between the element substrate 2 and the sealing substrate 3 inside the sealant 8 . The organic EL element 10 is a laminate having an anode 5 and a cathode 6 arranged to face each other and an organic layer 4 provided between them. The organic EL element 10 is embedded within the desiccant layer 7. However, the airtight space may not be completely filled with the desiccant layer 7 and voids may remain. The proportion of the desiccant layer in the airtight space may be, for example, 50 to 100% by volume, 60 to 100% by volume, 70 to 100% by volume, 80 to 100% by volume, or 90 to 100% by volume.

Regarding the elements other than the desiccant layer 7 in the organic EL device 1A, ordinary elements in the technical field can be applied, and an example thereof will be described below.

The element substrate 2 may be a rectangular glass substrate having insulation and translucency. An anode 5 (electrode) is formed on the element substrate 2 using ITO (Indium Tin Oxide), which is a transparent conductive material. The anode 5 is formed by patterning an ITO film formed on the element substrate 2 by a PVD (Physical Vapor Deposition) method such as a vacuum evaporation method or a sputtering method into a predetermined pattern shape by etching using a photoresist method. Ru. A part of the anode 5 serving as an electrode is drawn out to the end of the element substrate 2 and connected to a drive circuit.

An organic layer 4, which is a thin film containing an organic light-emitting material, is laminated on the upper surface of the anode 5 by, for example, a PVD method such as a vacuum evaporation method or a resistance heating method. The organic layer 4 may be formed from a single layer or may be formed from a plurality of layers having different functions. The organic layer 4 in this example has a four-layer structure in which a hole injection layer 4a, a hole transport layer 4b, a light emitting layer 4c, and an electron transport layer 4d are laminated in order from the anode 5 side. The hole injection layer 4a is formed of copper phthalocyanine (CuPc) with a thickness of, for example, several tens of nanometers. The hole transport layer 4b is formed of bis[N-(1-naphthyl)-N-phenyl]benzidine (α-NPD) with a film thickness of, for example, several tens of nanometers. The light emitting layer 4c is formed of tris(8-quinolinolato)aluminum (Alq ₃ ) with a thickness of several tens of nanometers, for example. The electron transport layer 4d is formed of lithium fluoride (LiF) with a thickness of several nm, for example.

A cathode 6 (electrode), which is a metal thin film formed by a PVD method such as a vacuum evaporation method, is laminated on the upper surface of the organic layer 4 (electron transport layer 4d). The material of the metal thin film may be, for example, an elemental metal with a small work function such as Al, Li, Mg, or In, or an alloy with a small work function such as Al-Li or Mg-Ag. The cathode 6 has a thickness of, for example, several 10 nm to several 100 nm, or 50 nm to 200 nm. A portion of the cathode 6 is drawn out to the end of the element substrate 2 and connected to a drive circuit.

The sealing substrate 3 is arranged to face the element substrate 2 with the organic layer 4 in between. A space between the outer peripheral portion of the sealing substrate 3 and the element substrate 2 is sealed with a sealant 8 . As the sealant 8, for example, an ultraviolet curable resin can be used.

The organic EL device 1B shown in FIG. An encapsulating sealant 8 that seals between the outer periphery and the element substrate 2, an outer desiccant layer 9 provided on the inner surface of the encapsulating sealant 8, and an organic The desiccant layer 7 fills the periphery of the EL element 10. In the organic EL device 1B as well, the organic EL element 10 is embedded in the desiccant layer 7. An airtight space between the element substrate 2 and the sealing substrate 3 is filled with a desiccant layer 7 and an outer desiccant layer 9. The outer desiccant layer 9 can be a layer containing, for example, oxide particles containing an alkaline earth oxide such as calcium oxide and a binder.

The organic EL device 1C shown in FIG. The desiccant layer 7 fills the space around the organic EL element 10 between the element substrate 2 and the sealing substrate 3 while being in contact with the sealing substrate 3 . In the case of the organic EL device 1C in FIG. 3, a member such as an encapsulating sealant that forms an airtight space around the organic EL element is not provided, but the organic EL element 10 has a water-capturing ability. By being embedded in the agent layer 7, it is possible to have a good light emission life.

The organic EL device 1D shown in FIG. It is composed of a sealant 8 that seals between the outer peripheral part and the element substrate 2, and a sealing layer 20 that covers the organic EL element 10 inside the sealant 8. The organic EL element 10 is embedded within the sealing layer 20. The sealing layer 20 has a laminated structure including a desiccant layer 7 and two inorganic films 22. An inorganic film 22, a desiccant layer 7, and an inorganic film 22 are laminated in this order from the organic EL element 10 side. That is, the sealing layer 20 has two inorganic films 22 as outermost layers and a desiccant layer 7 arranged inside them. The number of desiccant layers and inorganic films that constitute the sealing layer 20 is not limited, and a plurality of cured films and inorganic films may be alternately stacked. In the case of FIG. 4, the sealing layer 20 covers the organic EL element 10 and also covers the surface of the element substrate 2, but the entire surface of the element substrate 2 inside the sealant 8 need not be covered. The thickness of one desiccant layer constituting the sealing layer may be, for example, 0.1 to 30 μm.

The inorganic film 22 may be, for example, a film containing a silicon compound selected from silicon nitride (SiN), silicon oxide (SiO), silicon oxide containing nitrogen (SiON), and the like. The inorganic film 22 can be formed, for example, by chemical vapor deposition (CVD). The thickness of the inorganic film 22 may be, for example, 0.1 to 3 μm.

The organic EL device can be manufactured, for example, by a method that includes applying a desiccant composition to the element substrate 2 or the sealing substrate 3. A sealing layer having a laminated structure including a desiccant layer and an inorganic film like the organic EL device 1D in FIG. 4 can be manufactured, for example, by a method including applying a desiccant composition to the inorganic film.

In an example of a method for manufacturing an organic EL device, a laminate is prepared in which an organic EL element 10 having an organic layer 4 and the like is formed on an element substrate 2. In this case, a desiccant composition is applied onto a separately prepared sealing substrate 3 using a method such as a dispenser to form a desiccant layer 7. Thereafter, a sealant 8 is applied using a dispenser so as to surround the desiccant layer 7 applied on the sealing substrate 3. These operations may be performed in a glove box purged with nitrogen and having a dew point of -76°C or lower.

Next, the element substrate 2 on which the organic EL element is mounted and the sealing substrate 3 are bonded together with the desiccant layer 7 and the sealant 8 sandwiched between them. If necessary, the organic EL device 1A is obtained by curing the desiccant composition and/or the sealing agent by irradiating the obtained structure with ultraviolet rays and/or heating. The organic EL device 1B can also be manufactured by the same method except for forming the outer desiccant layer 9. The organic EL device 1C can be manufactured by the same method except that the encapsulating sealant is not formed. The organic EL device 1D can be manufactured by a method including sequentially forming an inorganic film and a desiccant layer on an organic EL element.

The water-capturing ability of the alkoxysilane compound and its stability under neutral conditions were verified through the tests shown below.

(Test 1)
An alkoxysilane compound (Si(THFA) ₄ ) represented by the following formula was synthesized by reacting tetraethoxysilane and tetrahydrofurfuryl alcohol.

Test solution 1-1 was prepared by adding the obtained alkoxysilane compound (Si(THFA) ₄ ) to diglyme containing 3% by mass of water. In test solution 1-1, the concentration of the alkoxysilane compound was 10% by mass. The container containing Test Solution 1-1 was covered and left in the air at room temperature for 1 hour.
An alkoxysilane compound (Si(THFA) ₄ ) and a photoacid were prepared in the same manner as Test Solution 1-1 except that a photoacid generator (Irgacure 290 (trade name), triarylsulfonium salt, manufactured by BASF) was further added. Test solution 1-2 containing a generator was prepared. In test solution 1-2, the concentration of the alkoxysilane compound was 10% by mass, and the concentration of the photoacid generator was 0.1% by mass. After irradiating Test Solution 1-2 with ultraviolet rays, the container containing Test Solution 1-2 was covered and left in the air at room temperature for 1 hour.
The water content of test solutions 1-1 and 1-2 while standing was measured by Karl Fischer method. Based on the change in water content, the change in water absorption capacity of each test liquid was determined.

(Test 2)
An alkoxysilane compound (HexSi(THFA) ₃ ) represented by the following formula was synthesized by a reaction between hexyltriethoxysilane and tetrahydrofurfuryl alcohol.

Test solution 2-1 containing an alkoxysilane compound but not containing a photoacid generator was prepared in the same manner as in Test 1 except that HexSi(THFA) ₃ was used as the alkoxysilane compound, and an alkoxysilane compound and a photoacid generator. Test solution 2-2 containing the following was prepared. In the case of test liquid 2-1, without irradiation with ultraviolet rays, in the case of test liquid 2-2, after irradiation with ultraviolet rays, the container containing each test liquid was covered and left in the air at room temperature for 1 hour. did. The water content of test solutions 2-1 and 2-2 was measured by Karl Fischer method while standing. Based on the change in water content, the change in water absorption capacity of each test liquid was determined.

(Test 3)
An alkoxysilane compound (PhSi(THFA) ₃ ) represented by the following formula was synthesized by reacting phenyltriethoxysilane and tetrahydrofurfuryl alcohol.

Test solution 3-1 containing an alkoxysilane compound but not containing a photoacid generator was prepared in the same manner as in Test 1 except that PhSi(THFA) ₃ was used as the alkoxysilane compound, and a test solution 3-1 containing an alkoxysilane compound and a photoacid generator was used. A test solution 3-2 containing the following was prepared. In the case of test liquid 3-1, without irradiation with ultraviolet rays, in the case of test liquid 3-2, after irradiation with ultraviolet rays, the container containing each test liquid was covered and left in the air at room temperature for 1 hour. did. The water content of test solutions 3-1 and 3-2 was measured by the Karl Fischer method while standing. Based on the change in water content, the change in water absorption capacity of each test liquid was determined.

(result)
FIG. 5, FIG. 6, and FIG. 7 are graphs showing the relationship between water capture capacity and standing time in Tests 1, 2, and 3, respectively. The maximum value of water capture capacity for each test solution is also shown in the graph. As shown in FIGS. 5 to 7, in test solutions 1-2, 2-2, and 3-2 under acidic conditions, water capture by hydrolysis of the alkoxysilane compound proceeded rapidly. On the other hand, under the conditions of neutral test liquids 1-1, 2-1, and 3-1, a low water absorption capacity was maintained, which confirmed that unintended progress of hydrolysis was suppressed. HexSi(THFA) ₃ and PhSi(THFA) ₃ tended to exhibit relatively higher stability at neutral conditions compared to Si(THFA) ₄ .

1A, 1B, 1C, 1D...Organic EL element, 2...Element substrate, 3...Sealing substrate, 4...Organic layer, 4a...Hole injection layer, 4b...Hole transport layer, 4c...Light emitting layer, 4d...Electron transport layer , 5... Anode, 6... Cathode, 7... Sealing layer, 8... Sealing agent, 9... Desiccant layer, 10... Light emitting part.

Claims (8)

A water-trapping component,
an acid generator;
including;
The water-trapping component contains an alkoxysilane compound represented by the formula: Si(OR ¹ ) _n (R ² ) _4-n ,
n represents an integer from 1 to 4,
R ¹ represents a monovalent organic group containing a carbon atom bonded to an oxygen atom bonded to Si,
R ² represents an alkyl group that may have a substituent or an aryl group that may have a substituent,
A plurality of R ¹ and R ² in the same molecule may be the same or different,
At least one selected from R ¹ and R ² in the same molecule is a group containing a 4-membered cyclic ether group, or a group containing a 5-membered cyclic ether group,
Desiccant composition. The group containing the 4-membered cyclic ether group has the following formula (1):

A group represented by the following formula (2):

The desiccant composition according to claim 1, wherein m is an integer of 0 to 5, and R ¹⁰ is a hydrogen atom or an alkyl group. The desiccant composition according to claim 1, further comprising an epoxy resin. Represented by the formula: Si(OR ¹ ) _n (R ² ) _4-n ,
n represents an integer from 1 to 4,
R ¹ is the following formula (A):

is a group represented by
R ² represents an alkyl group that may have a substituent or an aryl group that may have a substituent,
Multiple ^R2s in the same molecule may be the same or different,
Alkoxysilane compound. an element substrate;
a sealing substrate disposed opposite to the element substrate;
a light emitting section provided on the element substrate and having a pair of electrodes arranged opposite to each other and an organic layer provided between them;
a sealing layer provided between the element substrate and the sealing substrate and sealing the light emitting part,
The sealing layer comprises a cured product of the desiccant composition according to any one of claims 1 to 3.
Organic EL element. The organic EL according to claim 5, wherein the sealing layer fills a space around the light emitting part between the element substrate and the sealing substrate while being in contact with the element substrate and the sealing substrate. element. The organic EL element further includes an encapsulating sealant that seals the outer periphery of the element substrate and the sealing substrate,
6. The organic EL element according to claim 5, wherein the sealing layer fills at least a part of the airtight space around the light emitting part inside the sealant. The organic EL device according to claim 5, wherein the sealing layer has a laminated structure including a cured film containing a cured product of the desiccant composition and an inorganic film.

Images