JP7375585B2 - Method for manufacturing device structure - Google Patents

Description

The present invention relates to a device structure and a method for manufacturing the same.

Devices such as organic electroluminescent devices and flexible touch sensors may require the provision of components that inhibit the ingress of moisture into the device. For example, an organic electroluminescent device can include a base material such as a glass plate, and an element section including an electrode layer and a light emitting layer provided on the base material. Some materials included in the element portion may deteriorate due to the intrusion of moisture. Therefore, in order to suppress moisture from entering the element part, a sealing layer is sometimes formed to seal the element part.

In many devices, the sealing layer includes an organic sealing layer made of an organic material and an inorganic sealing layer made of an inorganic material (Patent Document 1). Conventionally, organic sealing layers have generally been formed under atmospheric pressure. Further, the inorganic sealing layer is often formed in a vacuum environment by a method such as a CVD method (Chemical Vapor Deposition).

Japanese Patent Application Publication No. 2018-147812

However, the process in a vacuum environment as described in Patent Document 1 increases the size and complexity of the inorganic sealing layer forming apparatus, resulting in high costs. In particular, in processes such as plasma CVD using plasma, particles such as plasma dust are generated, and these particles can cause deterioration of the element portion.

Against this background, there is a need to develop a technology that can form an inorganic sealing layer under atmospheric pressure. In order to meet this demand, a method of forming an inorganic sealing layer containing silicon nitride under atmospheric pressure using a polysilazane compound has recently been developed (Lina Sun, Kaho Uemura, Tatsuhiro Takahashi, Tsukasa Yoshida, Yoshiyuki Suzuri, "Interfacial Engineering in Solution Processing of Silicon-Based Hybrid Multilayer for High Performance Thin Film Encapsul ', ACS Appl. Mater. Interfaces, 11, 43425-43432 (2019)). However, the above-described inorganic sealing layer formed using a polysilazane compound easily cracks in a high-temperature environment. When cracks occur, the sealing ability is impaired, making it difficult to prevent moisture from entering the element portion.

The present invention was created in view of the above-mentioned problems, and includes a method for manufacturing a device structure that can manufacture a device structure that includes a layer containing silicon nitride and a sealing layer that can suppress cracks; and a device structure manufactured by the manufacturing method.

The inventors of the present invention have made extensive studies to solve the above problems. As a result, the present inventor discovered that the first sealing layer is formed by drying the first intermediate layer containing a thermoplastic elastomer and a solvent, and the second intermediate layer is formed by irradiating ultraviolet rays on the second intermediate layer containing a polysilazane compound. The inventors have discovered that the above-mentioned problems can be solved by using a sealing layer that includes a second sealing layer in combination, and have completed the present invention.
That is, the present invention includes the following.

[1] Step (a) of preparing a multilayer structure including a base material and an element section provided on the base material;
A method for manufacturing a device structure, comprising a step (b) of forming a sealing layer for sealing the element part,
The step (b) of forming the sealing layer includes a step (b1) of forming a first sealing layer, and a step (b2) of forming a second sealing layer,
The step (b1) of forming the first sealing layer includes a step (b1-1) of forming a first intermediate layer containing a thermoplastic elastomer and a solvent, and a step (b1-2) of drying the first intermediate layer. ) and,
The step (b2) of forming the second sealing layer includes a step (b2-1) of forming a second intermediate layer containing a polysilazane compound, and a step (b2-2) of irradiating the second intermediate layer with ultraviolet rays. A method of manufacturing a device structure, comprising:
[2] The method for manufacturing a device structure according to [1], wherein the step (b1-1) includes applying a resin composition containing the thermoplastic elastomer and the solvent.
[3] The thermoplastic elastomer consists of a hydrogenated aromatic vinyl compound-conjugated diene block copolymer and a hydrogenated aromatic vinyl compound-conjugated diene block copolymer modified with a silicon atom-containing polar group. The method for manufacturing a device structure according to [1] or [2], which is one or more types selected from the group.
[4] The method for manufacturing a device structure according to any one of [1] to [3], wherein the step (b2-1) includes applying a liquid composition containing the polysilazane compound.
[5] The method for manufacturing a device structure according to any one of [1] to [4], wherein step (b) includes performing the step (b1) and the step (b2) in this order. .
[6] The method for manufacturing a device structure according to any one of [1] to [5], wherein the element section is an organic electroluminescent element section.
[7] A device structure manufactured by the manufacturing method according to any one of [1] to [6].

According to the present invention, a device structure manufacturing method capable of manufacturing a device structure including a layer containing silicon nitride and a sealing layer capable of suppressing cracks; and a device manufactured by the manufacturing method structure; can be provided.

FIG. 1 is a cross-sectional view schematically showing a multilayer structure prepared in step (a) of a method for manufacturing a device structure according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing how a first sealing layer for sealing an element portion is formed on a multilayer structure in step (b1) according to an embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing how a second sealing layer for sealing the element portion is formed on the multilayer structure in step (b2) according to an embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing a device structure manufactured by a manufacturing method according to another embodiment of the present invention. FIG. 5 is a diagram showing a table showing the results of reference examples and comparative examples.

Hereinafter, the present invention will be described in detail by showing embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be implemented with arbitrary changes within the scope of the claims of the present application and equivalents thereof.

In the following description, unless otherwise specified, "(meth)acrylic" is a term that includes "acrylic", "methacrylic", and combinations thereof. For example, "(meth)acrylic acid alkyl ester" includes acrylic acid alkyl ester, methacrylic acid alkyl ester, or mixtures thereof.

For convenience of explanation, what is indicated by the word "solvent" in the following description includes not only a medium in a solution but also a dispersion medium in which a solid substance is dispersed.

[1. Overview of device structure manufacturing method]
A method for manufacturing a device structure according to an embodiment of the present invention includes a step (a) of preparing a multilayer structure including a base material and an element section provided on the base material; sealing the element section; (b) forming a sealing layer; Moreover, the step (b) of forming a sealing layer includes a step (b1) of forming a first sealing layer, and a step (b2) of forming a second sealing layer. Therefore, according to step (b), a sealing layer including a first sealing layer and a second sealing layer is formed.

The step (b1) of forming the first sealing layer includes a step (b1-1) of forming a first intermediate layer containing a thermoplastic elastomer and a solvent, and a step (b1-2) of drying the first intermediate layer. ,including. In the following description, the solvent used to form the first intermediate layer may be referred to as a "first solvent" to distinguish it from the solvent that can be used to form the second intermediate layer. When dried in step (b1-2), the first solvent can be removed from the first intermediate layer, resulting in the first sealing layer containing the thermoplastic elastomer. Since thermoplastic elastomers are typically organic materials, the first sealing layer can function as an organic sealing layer.

The step (b2) of forming the second sealing layer includes a step (b2-1) of forming a second intermediate layer containing a polysilazane compound, a step (b2-2) of irradiating the second intermediate layer with ultraviolet rays, including. When the second intermediate layer is irradiated with ultraviolet rays in step (b2-2), the polysilazane compound reacts with the irradiation of the ultraviolet rays, and a second sealing layer containing a reaction product of the reaction is obtained. Since the reaction product may include an inorganic material such as silicon nitride, the second sealing layer can function as an inorganic sealing layer.

In the device structure manufactured by the above manufacturing method, the second sealing layer containing silicon nitride is unlikely to crack. Specifically, generation of cracks in the second sealing layer can be suppressed in a high temperature environment. Therefore, according to the above manufacturing method, it is possible to manufacture a device structure including a second sealing layer containing silicon nitride and having a sealing layer capable of suppressing cracks. In addition, in the device structure obtained in this way, the element part is sealed by a sealing layer that includes a combination of the first sealing layer and the second sealing layer, and therefore, the intrusion of moisture into the element part is usually prevented. can be effectively suppressed.

[2. Step (a): Preparation of composite layer]
FIG. 1 is a cross-sectional view schematically showing a multilayer structure 100 prepared in step (a) of a method for manufacturing a device structure according to an embodiment of the present invention. As shown in FIG. 1, in step (a), a composite 100 including a base material 110 and an element section 120 is prepared.

As the base material 110, any material that can constitute a device structure can be appropriately employed. Examples of the base material 110 include a glass plate, a resin plate, and a resin film. The base material may include only one layer or may include multiple layers. For example, a base material 110 including a resin film and a barrier layer provided on the surface thereof may be used.

As the element section 120, any element that can constitute a device structure can be appropriately employed. Typically, the element section 120 includes one or more conductor layers. The layer represented by the term "conductor layer" includes various layers that exhibit their functions through the movement of electrons within the layer. Therefore, the term "conductor layer" may include, for example, not only a highly conductive layer such as a metal layer, but also an organic thin layer such as a light emitting layer having a relatively low conductivity. In the method for manufacturing a device structure according to the present embodiment, a sealing layer (not shown in FIG. 1) is usually formed in order to suppress deterioration of the conductor layer due to moisture.

Examples of the conductor layer include, for example, an electrode layer, a light emitting layer, and a combination thereof that constitute an organic electroluminescent element section; and patterned wiring that constitutes a touch panel. The conductor layer may be provided on the base material 110 to occupy a wide area. Further, the conductor layer may be provided with any surface shape such as a strip shape, a thin line shape, a rectangular shape, a dot shape, etc., like wiring and other structures on the base material 110. good.

The number of conductor layers included in the element section 120 may be one, or two or more. When the element section 120 includes two or more layers, these layers may be arranged without overlapping, or some or all of these layers may be overlapping.

The element section 120 may include members other than the conductor layer inside or on the surface of the element section 120. Examples of such members include members that maintain the mechanical structure of the element section 120. Specific examples of this member include constituent members of display elements such as liquid crystal cells and organic electroluminescent elements.

In this embodiment, an example of an organic electroluminescent element section including a first electrode layer 121, a light emitting layer 122, and a second electrode layer 123 in this order in the thickness direction will be described as the element section 120. The first electrode layer 121, the light emitting layer 122, and the second electrode layer 123 are all conductor layers, and the light emitting layer 122 normally emits light when a voltage is applied from the first electrode layer 121 and the second electrode layer 123. It can occur. Examples of materials for the light-emitting layer 122 include polyparaphenylenevinylene-based, polyfluorene-based, and polyvinylcarbazole-based materials. Further, the light-emitting layer 122 may have a laminate of a plurality of layers emitting light of different colors, or a mixed layer in which a layer of a certain dye is doped with a different dye. Furthermore, the element section 120 may include functional layers (not shown) such as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an equipotential surface forming layer, and a charge generation layer. .

The multilayer structure 100 can be manufactured, for example, by a manufacturing method that includes forming the element section 120 on the base material 110. A method for forming the element portion 120 includes, for example, a method of forming a conductor layer on the base material 110 by a method such as sputtering or vapor deposition.

[3. Step (b): Formation of sealing layer]
In the method for manufacturing a device structure according to an embodiment of the present invention, after preparing the composite layer 100 in the step (a), the step (b) of forming a sealing layer for sealing the element object 120 is performed. . The sealing layer is formed so as to seal at least a portion of the element part 120, and is preferably provided so as to seal all or most of the element object 120. In this embodiment, an example will be described in which a sealing portion is formed so as to seal the entire portion of the element portion 120 that is not in contact with the surface 110U of the base material 110.

Step (b) includes a step (b1) of forming a first sealing layer and a step (b2) of forming a second sealing layer. Step (b) may include performing step (b1) and step (b2) in this order. Further, step (b) may include performing step (b2) and step (b1) in this order. In this embodiment, a process (b) including performing a process (b1) and a process (b2) in this order will be described as an example.

[4. Step (b1): Formation of first sealing layer]
FIG. 2 is a cross-sectional view schematically showing how a first sealing layer 210 for sealing the element section 120 is formed on the multilayer structure 100 in step (b1) according to an embodiment of the present invention. It is. In step (b1), as shown in FIG. 2, a first sealing layer 210 is formed. In this embodiment, an example will be described in which the first sealing layer 210 is formed on the surface 120U of the element section 120. In this example, since there is no other layer between the first sealing layer 210 and the element section 120, the formed first sealing layer 210 can directly seal the element section 120. Here, the term "direct" sealing of the element part by a layer means that there is no other layer between the layer and the element part. However, there may be another layer (for example, a second sealing layer, an arbitrary layer) between the first sealing layer 210 and the element section 120, and in that case, the first sealing layer 210 is The element section 120 can be indirectly sealed through the above layer.

[4.1. Step (b1-1): Formation of first intermediate layer]
Step (b1) includes a step (b1-1) of forming a first intermediate layer containing a thermoplastic elastomer and a first solvent. This first intermediate layer can be formed as a layer of a resin composition containing a thermoplastic elastomer and a first solvent.

(thermoplastic elastomer)
A thermoplastic elastomer is a material that exhibits the characteristics of rubber at room temperature, but becomes plasticized and can be molded at high temperatures. Such thermoplastic elastomers have the property of being difficult to elongate or break when loaded with a small force. Specifically, the thermoplastic elastomer can exhibit a Young's modulus of 0.001 to 1 GPa and a tensile elongation (elongation at break) of 100 to 1000% at 23°C. Thermoplastic elastomers also have a storage modulus that rapidly decreases in a high temperature range of 40°C to 200°C, and the loss tangent tan δ (loss modulus/storage modulus) reaches a peak or exceeds 1. It shows and can be softened. Young's modulus and tensile elongation can be measured according to JIS K7113. Further, the loss tangent tan δ can be measured using a commercially available dynamic viscoelasticity measurement device.

Thermoplastic elastomers generally do not contain residual solvent or contain only a small amount. Therefore, thermoplastic elastomers have the advantage of producing less outgas and the advantage that sealing can be performed in a simple process that does not involve crosslinking treatment or the like.

Polymers can be used as thermoplastic elastomers. Examples of polymers that can be used as thermoplastic elastomers include ethylene-α-olefin copolymers such as ethylene-propylene copolymers; ethylene-α-olefin-polyene copolymers; ethylene-methyl methacrylate, ethylene-butyl acrylate. Copolymers of ethylene and unsaturated carboxylic acid esters, such as copolymers; copolymers of ethylene and vinyl fatty acids, such as ethylene-vinyl acetate copolymers; ethyl acrylate, butyl acrylate, hexyl acrylate , 2-ethylhexyl acrylate, lauryl acrylate, and other acrylic acid alkyl ester polymers; polybutadiene, polyisoprene, acrylonitrile-butadiene copolymer, butadiene-isoprene copolymer, butadiene-(meth)acrylic acid alkyl ester copolymer Diene copolymers such as butadiene-(meth)acrylic acid alkyl ester-acrylonitrile copolymer, butadiene-(meth)acrylic acid alkyl ester-acrylonitrile-styrene copolymer; butylene-isoprene copolymer; styrene - Butadiene random copolymer, styrene-isoprene random copolymer, styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene block copolymer, styrene-isoprene-styrene block copolymer Aromatic vinyl compound-conjugated diene copolymer such as; hydrogenated styrene-butadiene random copolymer, hydrogenated styrene-isoprene random copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-butadiene- Hydrogenated aromatic vinyl compound-conjugated diene copolymers, such as styrene block copolymers, hydrogenated styrene-isoprene block copolymers, and hydrogenated styrene-isoprene-styrene block copolymers; low-crystalline polybutadiene; styrene grafts Examples include ethylene-propylene elastomer; thermoplastic polyester elastomer; and ethylene ionomer. One type of thermoplastic elastomer may be used alone, or two or more types may be used in combination in any ratio.

As the thermoplastic elastomer, a hydrogenated aromatic vinyl compound-conjugated diene block copolymer is preferred in order to obtain the desired effects of the present invention. The hydrogenated aromatic vinyl compound-conjugated diene block copolymer refers to a hydrogenated aromatic vinyl compound-conjugated diene block copolymer. That is, the hydrogenated aromatic vinyl compound-conjugated diene block copolymer is a non-aromatic carbon-carbon unsaturated bond of the aromatic vinyl compound-conjugated diene block copolymer, an aromatic carbon-carbon bond, or It represents a polymer having a structure obtained by partially or completely hydrogenating both of these. However, the above-mentioned hydride is not limited by its manufacturing method.

As the aromatic vinyl compound, styrene and its derivatives; vinylnaphthalene and its derivatives are preferred. It is particularly preferable to use styrene because of its industrial availability. On the other hand, as the conjugated diene, a chain conjugated diene (linear conjugated diene, branched conjugated diene) is preferable. Preferred examples of the conjugated diene include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. Among these, 1,3-butadiene and isoprene are particularly preferred because of their industrial ease of availability.

The mass fraction of all aromatic vinyl monomer units in the entire aromatic vinyl compound-conjugated diene block copolymer is defined as wA, and all the conjugated diene monomer units are aromatic vinyl compound-conjugated diene block copolymer. When wB is the mass fraction occupied by the whole, the ratio of wA and wB (wA/wB) is preferably within a specific range. Specifically, the ratio (wA/wB) is preferably 20/80 or more, more preferably 30/70 or more, and preferably 60/40 or less, more preferably 55/45 or less. When the ratio wA/wB is equal to or greater than the lower limit of the range, the heat resistance of the first sealing layer can be improved. Moreover, when it is below an upper limit, the flexibility of a 1st sealing layer can be improved. Further, when the ratio (wA/wB) is within the above range, the temperature range in which the first sealing layer has rubber elasticity can be expanded, so the temperature range in which the device structure has flexibility can be expanded. can.

Examples of the aromatic vinyl compound-conjugated diene block copolymer include styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene block copolymer, styrene-isoprene-styrene block copolymer, and mixtures thereof are preferred. More specific examples of these include JP-A-2-133406, JP-A-2-305814, JP-A-3-72512, JP-A-3-74409, and International Publication No. 2015/099079. Examples include those described in technical documents such as .

The hydrogenation rate of the hydrogenated aromatic vinyl compound-conjugated diene block copolymer is preferably 90% or more, more preferably 97% or more, particularly preferably 99% or more. The higher the hydrogenation rate, the better the heat resistance and light resistance of the first sealing layer. The hydrogenation rate of the hydride can be determined by ¹ H-NMR measurement.

The hydrogenation rate of the non-aromatic carbon-carbon unsaturated bonds of the hydrogenated aromatic vinyl compound-conjugated diene block copolymer is preferably 95% or more, more preferably 99% or more. When the hydrogenation rate of non-aromatic carbon-carbon unsaturated bonds is high, the light resistance and oxidation resistance of the first sealing layer can be further increased.

The hydrogenation rate of the aromatic carbon-carbon unsaturated bond of the hydrogenated aromatic vinyl compound-conjugated diene block copolymer is preferably 90% or more, more preferably 93% or more, particularly preferably 95% or more. be. When the hydrogenation rate of the aromatic carbon-carbon unsaturated bond is high, the glass transition temperature of the hydride becomes high, so that the heat resistance of the first sealing layer can be effectively improved. Furthermore, the photoelastic coefficient of the first sealing layer can be lowered to reduce the occurrence of retardation.

It is particularly preferable that the hydrogenated aromatic vinyl compound-conjugated diene block copolymer has a structure in which both non-aromatic carbon-carbon unsaturated bonds and aromatic carbon-carbon unsaturated bonds are hydrogenated. .

A particularly preferred block form of the hydrogenated aromatic vinyl compound-conjugated diene block copolymer is such that the block [A] of the hydrogenated aromatic vinyl polymer is bonded to both ends of the block [B] of the hydrogenated conjugated diene polymer. Triblock copolymer; a pentablock copolymer in which a polymer block [B] is bonded to both ends of a polymer block [A], and a polymer block [A] is bonded to the other end of both polymer blocks [B]. It is a block copolymer. In particular, a triblock copolymer of [A]-[B]-[A] is particularly preferred because it is easy to manufacture and the physical properties of the thermoplastic elastomer can be set within a desired range.

The hydrogenated aromatic vinyl compound-conjugated diene block copolymer can be produced, for example, by the method described in International Publication No. 2015/099079 and Japanese Patent Application Publication No. 2016-204217.

Further, as the thermoplastic elastomer, a polymer having a silicon atom-containing polar group may be used. Examples of such polymers include, for example, modified products with silicon atom-containing polar groups of the polymers listed as examples of polymers that can be used as thermoplastic elastomers. When a polymer having a silicon-containing polar group is employed as the thermoplastic elastomer, the adhesion between the first sealing layer and other members can be improved.

Hereinafter, the polymer used in the reaction to obtain the above-mentioned modified product may be appropriately referred to as a "pre-reaction polymer." The above-mentioned modified product may have a structure obtained, for example, by graft polymerization of a pre-reaction polymer and a compound having a silicon atom-containing polar group as a monomer. However, the modified product is not limited by its manufacturing method.

As the silicon atom-containing polar group, an alkoxysilyl group is preferred. Examples of compounds having an alkoxysilyl group as a silicon atom-containing polar group include vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, and p-styryltrimethoxysilane. Methoxysilane, p-styryltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acrylic Ethylenically unsaturated silane compounds such as roxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, and 2-norbornen-5-yltrimethoxysilane are mentioned.

By reacting the pre-reaction polymer with a compound having a silicon atom-containing polar group, a silicon atom-containing polar group can be introduced into the pre-reaction polymer to obtain a modified product having a silicon atom-containing polar group. When introducing an alkoxysilyl group as a silicon atom-containing polar group, the amount of alkoxysilyl group introduced is preferably 0.1 part by weight or more, more preferably 0.2 part by weight or more, based on 100 parts by weight of the polymer before reaction. , more preferably 0.3 parts by weight or more, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, still more preferably 3 parts by weight or less. When the amount of alkoxysilyl groups introduced falls within the above range, it is possible to prevent the degree of crosslinking between the alkoxysilyl groups decomposed by moisture from becoming excessively high, so that high adhesiveness can be maintained. Examples of the substance having an alkoxysilyl group and the modification method used for introducing the alkoxysilyl group include those described in International Publication No. 2015/099079.

The amount of polar groups introduced can be measured by ¹ H-NMR spectrum. Furthermore, when measuring the amount of introduced polar groups, if the amount introduced is small, the number of integrations can be increased.

Among the above-mentioned thermoplastic elastomers, hydrogenated aromatic vinyl compound-conjugated diene block copolymers and hydrogenated aromatic vinyl compound-conjugated diene block copolymers are preferred from the viewpoint of significantly obtaining the desired effects of the present invention. One or more types selected from the group consisting of modified products with silicon atom-containing polar groups are preferred. Among these, particularly preferred are hydrogenated aromatic vinyl compound-conjugated diene block copolymers modified with silicon atom-containing polar groups.

Among the hydrogenated aromatic vinyl compound-conjugated diene block copolymers modified with silicon atom-containing polar groups, modified products in which an alkoxysilyl group is introduced as the silicon atom-containing polar group are preferred. Generally, introducing an alkoxysilyl group as a polar group into a pre-reaction polymer such as a hydrogenated aromatic vinyl compound-conjugated diene block copolymer is sometimes called silane modification. In silane modification, an alkoxysilyl group may be directly bonded to the pre-reaction polymer, or may be bonded via a divalent organic group such as an alkylene group. Hereinafter, a polymer obtained by silane modification of a pre-reaction polymer is also referred to as a "silane modified product".

Therefore, as the hydrogenated aromatic vinyl compound-conjugated diene block copolymer modified with a silicon atom-containing polar group, a silane-modified hydrogenated aromatic vinyl compound-conjugated diene block copolymer is preferable. Among them, silane-modified products of hydrogenated styrene-butadiene block copolymer, silane-modified products of hydrogenated styrene-butadiene-styrene block copolymer, silane-modified product of hydrogenated styrene-isoprene block copolymer, and hydrogenated styrene Particularly preferred are one or more silane-modified products selected from the group consisting of silane-modified products of isoprene-styrene block copolymers.

The weight average molecular weight (Mw) of the thermoplastic elastomer is not particularly limited, but is preferably 20,000 or more, more preferably 30,000 or more, even more preferably 35,000 or more, and preferably 200,000 or less, more preferably Preferably it is 100,000 or less, more preferably 70,000 or less. The weight average molecular weight of the thermoplastic elastomer can be measured in terms of polystyrene by gel permeation chromatography using tetrahydrofuran as a solvent. Further, the molecular weight distribution (Mw/Mn) of the thermoplastic elastomer is preferably 4 or less, more preferably 3 or less, still more preferably 2 or less, and preferably 1 or more. When the weight average molecular weight Mw and molecular weight distribution Mw/Mn of the thermoplastic elastomer are within the above ranges, the mechanical strength and heat resistance of the first sealing layer can be improved.

The glass transition temperature of the thermoplastic elastomer is not particularly limited, but is preferably 40°C or higher, more preferably 70°C or higher, and preferably 200°C or lower, more preferably 180°C or lower, and still more preferably 160°C or lower. . In addition, when a thermoplastic elastomer containing a block copolymer is used, the adhesiveness of the first sealing layer can be improved by adjusting the glass transition temperature by changing the weight ratio of each polymer block. A balance can be achieved with flexibility. The glass transition temperature of the resin can be measured using a differential scanning calorimeter (DSC) at a rate of 10° C./min.

In the resin composition, the thermoplastic elastomer may be dissolved or dispersed in the first solvent. Among these, it is preferable that the thermoplastic elastomer is dissolved in the first solvent.

The proportion of the thermoplastic elastomer in the resin composition is not particularly limited, and can be adjusted within a range that provides desired properties. Specifically, the amount of the thermoplastic elastomer based on 100% by weight of the total amount of the resin composition is preferably 1% by weight or more, more preferably 3% by weight or more, and preferably 40% by weight or less, more preferably 30% by weight. % or less, more preferably 20% by weight or less.

(first solvent)
As the first solvent, a solvent capable of dissolving or dispersing the thermoplastic elastomer can be used. Further, the first solvent may be used alone or in any combination of two or more. Among these, it is preferable to use a non-aqueous solvent as the first solvent since the element portion to be sealed generally has low durability against moisture. Furthermore, from the viewpoint of suppressing damage to the element portion and effectively suppressing moisture infiltration, it is preferable to use a nonpolar solvent as the first solvent.

Examples of nonpolar solvents include cyclohexane, methylcyclohexane, ethylcyclohexane, hexane, toluene, benzene, xylene, decahydronaphthalene, tetrahydronaphthalene, trimethylbenzene, cyclooctane, cyclodecane, octane (e.g., normal octane), dodecane, and tridecane. , tetradecane, and cyclododecane.

The amount of the non-polar solvent to make the total amount of the first solvent 100% by weight is preferably 95% by weight or more, more preferably 99% by weight or more, even more preferably 99.9% by weight or more, and ideally 100% by weight. %.

Preferably, the first solvent includes a high boiling point solvent having a high boiling point. The boiling point of the high boiling point solvent at 1 atm (1.01325×10 ⁵ Pa) is preferably 90°C or higher, more preferably 100°C or higher, even more preferably 125°C or higher, even more preferably 150°C or higher, particularly preferably 175°C. That's all. When the first solvent contains a high boiling point solvent, the formation of unevenness on the surface of the first sealing layer obtained by drying the first intermediate layer as a layer of the resin composition containing the first solvent is suppressed. The surface can be made smooth. Further, nozzle clogging can be suppressed during coating of the resin composition using an inkjet printing method. The upper limit of the boiling point of the high boiling point solvent at 1 atm is preferably 300°C or lower, more preferably 250°C or lower. When the boiling point of the high boiling point solvent is below the upper limit of the above range, the first intermediate layer can be easily dried.

With respect to the total amount of the first solvent (100% by weight), the amount of the high boiling point solvent is preferably 10% by weight or more, more preferably 25% by weight or more, even more preferably 50% by weight or more, even more preferably 70% by weight or more, It is particularly preferably 80% by weight or more, and usually 100% by weight or less.

(Optional ingredients)
The resin composition used to form the first intermediate layer may further contain arbitrary components in combination with the thermoplastic elastomer and the first solvent. For example, the resin composition may include hygroscopic particles as an optional component.

Hygroscopic particles refer to particles that have a high rate of weight change when left standing for 24 hours at 20° C. and 90% RH. The specific range of the weight change rate is usually 3% or more, preferably 10% or more, and more preferably 15% or more. There is no particular restriction on the upper limit of the weight change rate, but it may be, for example, 100% or less. Since the hygroscopic particles having such high hygroscopicity can absorb a large amount of moisture with a small amount, it is possible to effectively suppress moisture from permeating the sealing layer. As a result, the rubber properties of the thermoplastic elastomer are advantageously not impaired.

The weight change rate of the hygroscopic particles can be calculated using the following formula (K1). In the following formula (K1), W1 represents the weight of the particles before standing in an environment of 20°C and 90% Rh, and W2 represents the weight of the particles after standing in an environment of 20°C and 90% Rh for 24 hours. Represents weight.
Weight change rate (%) = ((W2-W1)/W1) x 100 (K1)

Examples of materials contained in the hygroscopic particles include basic hygroscopic materials and acidic hygroscopic materials. Basic moisture absorbers include, for example, compounds containing alkali metals, alkaline earth metals, and aluminum (oxides, hydroxides, salts, etc.) but do not contain silicon (for example, barium oxide, magnesium oxide, (calcium oxide, strontium oxide, aluminum hydroxide, hydrotalcite, etc.); organometallic compounds described in JP-A No. 2005-298598; clay containing metal oxides; and the like. Further, examples of the acidic moisture absorbing material include inorganic compounds containing silicon (eg, silica gel, nanoporous silica, and zeolite).

The material for the hygroscopic particles is preferably one or more substances selected from the group consisting of zeolite and hydrotalcite. Among them, zeolites generally have a particularly high moisture absorption capacity. Specifically, zeolite can easily achieve a high weight change rate of 10% to 30% when left for 24 hours at 20° C. and 90% RH. Zeolites also release water when dried, so they can be reused. One type of material for the hygroscopic particles may be used alone, or two or more types may be used in combination in any ratio.

The primary particle diameter of the hygroscopic particles is preferably 30 nm or more, more preferably 40 nm or more, and preferably 150 nm or less, more preferably 80 nm or less. The primary particle diameter of the hygroscopic particles refers to the number average particle diameter of the primary particles. The primary particle diameter of the hygroscopic particles can be measured in the state of a dispersion liquid dispersed in a solvent using a particle diameter measuring device using a dynamic light scattering method. If the primary particle size of the hygroscopic particles cannot be measured by dynamic light scattering, the primary particle size may be measured by observation using an electron microscope. Specifically, it can be measured by the following method. The sum of the short axis and long axis of each of the 50 primary particles is determined by observation using an electron microscope, and the resulting sum is divided by 2 to measure the particle diameter of each particle. The arithmetic mean value of the particle diameters of the 50 primary particles thus measured can be taken as the primary particle diameter. When determining the primary particle diameter by observation using an electron microscope, a film may be produced from the resin composition and particles in a cross section of the film may be observed.

The refractive index of the hygroscopic particles at a measurement wavelength of 589 nm is preferably 1.2 or more and 3.0 or less. When hygroscopic particles having such a refractive index are used, the haze of the first sealing layer can be reduced and a sealing layer with excellent transparency can be realized.

The hygroscopic particles contained in the resin composition are preferably dispersed in the first solvent. When a resin composition containing dispersed hygroscopic particles is used, it is usually possible to form a first sealing layer containing dispersed hygroscopic particles.

The proportion of hygroscopic particles in the resin composition is not particularly limited, and can be adjusted within a range that provides desired properties. Specifically, the amount of hygroscopic particles based on 100% by weight of the total solid content of the resin composition is preferably 5% by weight or more, more preferably 10% by weight or more, and preferably 60% by weight or less, preferably 40% by weight or more. It is not more than 30% by weight, more preferably not more than 30% by weight. The solid content of the resin composition refers to components remaining after drying the resin composition and volatilizing the first solvent, and usually refers to components other than the first solvent contained in the resin composition. When the amount of hygroscopic particles is equal to or greater than the lower limit, the effect of suppressing moisture intrusion of the first sealing layer can be enhanced. Moreover, when the amount of hygroscopic particles is below the above-mentioned upper limit, the transparency of the first sealing layer can be increased.

Examples of optional components that may be included in the resin composition include dispersants, plasticizers, light stabilizers, ultraviolet absorbers, antioxidants, lubricants, and inorganic fillers. Regarding the types, properties, and amounts of these arbitrary components, those described in International Publication No. 2019/220896 can be adopted, for example.

One type of arbitrary components may be used alone, or two or more types may be used in combination in any ratio.

(Characteristics of resin composition)
It is preferable that the resin composition has a small haze of a cured product obtained after drying the resin composition. Specifically, the haze of the cured product is preferably 1.0% or less, more preferably 0.3% or less, still more preferably 0.1% or less, and usually 0% or more. The haze of the cured product represents the value measured for a sample formed from the cured product into a film with a thickness of 10 μm. Haze can be measured by using a turbidity meter.

It is preferable that the resin composition is a liquid composition. By using a liquid resin composition, the first intermediate layer can be easily formed by a coating method. The viscosity of this liquid resin composition is preferably 1 cP or more, more preferably 2 cP or more, particularly preferably 3 cP or more, and preferably 5000 cP or less, more preferably 1000 cP or less, still more preferably 500 cP or less, even more preferably 50 cP. It is more preferably 30 cP or less, particularly preferably 20 cP or less. When the viscosity of the resin composition is above the lower limit of the above range, a thick first intermediate layer can be formed, and therefore a first sealing layer having high sealing ability can be easily formed. Further, when the viscosity of the resin composition is below the upper limit of the above range, the first intermediate layer can be easily formed by a coating method. In particular, when the viscosity is 50 cP or less, the first intermediate layer can be formed by inkjet printing. The viscosity can be measured using a tuning fork vibratory viscometer (eg, tuning fork vibratory viscometer SV-10 manufactured by A&D Co., Ltd.) at a measurement temperature of 25° C.±2° C.

The proportion of solids contained in the resin composition is not particularly limited, and is preferably adjusted appropriately so that properties such as viscosity are within a desired range. Specifically, the amount of solid content based on 100% by weight of the total amount of the resin composition is preferably 1% by weight or more, more preferably 3% by weight or more, and preferably 40% by weight or less, more preferably 30% by weight. The amount is not more than 20% by weight, and more preferably not more than 20% by weight.

(Method for forming first intermediate layer)
In step (b1-1), the aforementioned resin composition containing a thermoplastic elastomer and a first solvent is usually prepared, and a layer of this resin composition is formed to obtain a first intermediate layer. The formation of the resin composition layer is preferably performed by a method that includes coating the resin composition. Thereby, the first intermediate layer can be easily formed.

Examples of coating methods include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, print coating, gravure coating, and die coating. , gap coating method, and dipping method. Among these, printing methods such as screen printing and inkjet printing are preferred, and inkjet printing is particularly preferred.

[4.2. Step (b1-2): Drying of first intermediate layer]
Step (b1) includes a step (b1-2) of drying the first intermediate layer after obtaining the first intermediate layer in step (b1-1). By drying the first intermediate layer, the first solvent is removed from the first intermediate layer, and a first sealing layer formed of the solid content of the resin composition is obtained.

Examples of the drying method include natural drying, heating drying, reduced pressure drying, and reduced pressure heating drying. If natural drying is achieved simply by leaving at room temperature for a short period of time, no specific drying operation may be necessary. However, since the first intermediate layer can normally contain a large amount of the first solvent, it is preferable to accelerate drying by heating, reducing pressure, or the like.

The thickness of the first sealing layer obtained is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 2 μm or more, and preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. be. When the thickness of the first sealing layer is equal to or greater than the lower limit, moisture infiltration can be effectively suppressed. Moreover, when the thickness of the first sealing layer is equal to or less than the upper limit value, it is possible to reduce the thickness of the device structure.

The haze of the first sealing layer is preferably 0.5% or less, more preferably 0.15% or less, particularly preferably 0.05% or less. When the haze is below the above range, the transparency of the first sealing layer can be increased, so it is suitably used in locations where light transmission is required in device structures such as organic electroluminescent devices and flexible touch sensors. be able to. Haze can be measured by using a turbidity meter.

[5. Step (b2): Formation of second sealing layer]
FIG. 3 is a cross-sectional view schematically showing how a second sealing layer 220 sealing the element section 120 is formed on the multilayer structure 100 in step (b2) according to an embodiment of the present invention. It is. In step (b2), as shown in FIG. 3, a second sealing layer 220 is formed. In this embodiment, an example will be described in which the second sealing layer 220 is formed on the surface 210U of the first sealing layer 210. In this example, since the first sealing layer 210 is provided between the second sealing layer 220 and the element section 120, the second sealing layer 220 that is formed passes through the first sealing layer 210 to the element section. 120 can be sealed indirectly. However, there may be any layer other than the first sealing layer 210 between the second sealing layer 220 and the element section 120, and in that case, the second sealing layer 220 may be any layer other than the above-mentioned arbitrary layer. The element section 120 can be indirectly sealed via the . Further, there may be no other layer between the second sealing layer 220 and the element section 120, and in that case, the second sealing layer 220 can directly seal the element section 120.

[5.1. Step (b2-1): Formation of second intermediate layer]
Step (b2) includes a step (b2-1) of forming a second intermediate layer containing a polysilazane compound. Polysilazane compounds are polymers with silicon-nitrogen bonds. As polysilazane compounds, for example, polysilazane compounds which can be used as precursors of ceramics such as SiO ₂ , Si ₃ N ₄ and intermediate solid solutions of both SiO _x N _y may be used.

Preferred polysilazane compounds include, for example, compounds containing repeating units represented by the following formula (1).

In formula (1), R ¹ , R ² and R ³ each independently represent one or more groups selected from the group consisting of a hydrogen atom and a monovalent organic group. Monovalent organic groups include aliphatic hydrocarbon groups such as alkyl groups and alkenyl groups; alicyclic hydrocarbon groups such as cycloalkyl groups; aromatic hydrocarbon groups such as aryl groups; alkylsilyl groups; alkylamino groups. ;alkoxy group; and the like. As the polysilazane compound represented by formula (1), those described in JP-A-8-112879 may be used.

Among them, from the viewpoint of obtaining a second sealing layer with excellent sealing ability, R ¹ , R ² and R ³ are preferably hydrogen atoms. A polysilazane compound in which R ¹ , R ² and R ³ in the repeating unit are all hydrogen atoms is sometimes called perhydropolysilazane. The number average molecular weight (Mn) of perhydropolysilazane may be, for example, about 600 to 2000 (in terms of polystyrene).

Preferred other polysilazane compounds include, for example, silicon alkoxide-adducted polysilazane obtained by reacting a polysilazane compound containing a repeating unit represented by formula (1) with silicon alkoxide (Japanese Patent Application Laid-Open No. 5-238827), glycidol, etc. Glycidol-added polysilazane obtained by reacting (JP-A-6-122852), alcohol-added polysilazane obtained by reacting alcohol (JP-A-6-240208), and metal carboxylic acid obtained by reacting metal carboxylates. Salt-acid-added polysilazane (JP-A-6-299118), acetylacetonate-complex-adducted polysilazane obtained by reacting a metal-containing acetylacetonate complex (JP-A-6-306329), and acetylacetonate-added polysilazane obtained by adding metal fine particles. Polysilazane added with fine metal particles (Japanese Patent Application Laid-Open No. 7-196986), etc.

One type of polysilazane compound may be used alone, or two or more types may be used in any combination. For example, a combination of perhydropolysilazane and an organopolysilazane in which some of the hydrogen atoms bonded to the Si atoms of perhydropolysilazane are substituted with an organic group such as an alkyl group may be used. When perhydropolysilazane and organopolysilazane are used in combination, the toughness of the second sealing layer can be increased, so cracks can be suppressed. In particular, when an organopolysilazane substituted with a methyl group is used in combination with perhydropolysilazane, toughness can be significantly increased.

However, in this embodiment, it is preferable to use only perhydropolysilazane as the polysilazane compound. Conventionally, second sealing layers formed using only perhydropolysilazane have been particularly prone to cracking. However, even when such a second sealing layer is formed, which is likely to cause cracks, cracks can be suppressed by combining it with the first sealing layer. Therefore, from the viewpoint of effectively utilizing the effect of suppressing cracks in the second sealing layer formed using a polysilazane compound by the combination of the first sealing layer and the second sealing layer, only perhydropolysilazane was used. is preferably used as the polysilazane compound.

Polysilazane compounds can generally be liquid or solid compounds. Commercially available products may be used as such polysilazane compounds.

The formation of the second intermediate layer containing the polysilazane compound is preferably performed by a method that includes coating a liquid composition containing the polysilazane compound. According to this method, the second intermediate layer can be easily formed.

The liquid composition may include a solvent as an optional component. Hereinafter, the solvent used to form the second intermediate layer may be referred to as a "second solvent" to distinguish it from the first solvent used to form the first intermediate layer. As the second solvent, a solvent with low reactivity to the polysilazane compound is preferred, and an organic solvent is particularly preferred. Examples of the second solvent include hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons; halogenated hydrocarbon solvents; ether solvents such as aliphatic ether solvents and alicyclic ether solvents. ; can be mentioned. Specific examples include hydrocarbon solvents such as pentane, hexane, cyclohexane, toluene, xylene, Solvesso, and turbene; halogenated hydrocarbon solvents such as methylene chloride and tricoloroethane; ether solvents such as dibutyl ether, dioxane, and tetrahydrofuran; Can be mentioned. One type of second solvent may be used alone, or two or more types may be used in combination in any ratio.

The amount of the second solvent in the liquid composition is preferably adjusted so that the concentration of the polysilazane compound in the liquid composition is within an appropriate range. To give a specific range, the amount of the polysilazane compound is preferably 0.2% to 35% by weight based on 100% by weight of the total amount of the liquid composition.

The liquid composition may contain any components other than the polysilazane compound and the second solvent.

There are no particular limitations on the method of applying the liquid composition. As an example of the coating method, the same method as the coating method of the resin composition used for forming the first intermediate layer may be used. By such coating, the second intermediate layer as a layer of the liquid composition can be formed in an atmospheric pressure environment.

[5.2. Step (b2-3): Drying of second intermediate layer]
When the second intermediate layer formed in step (b2-1) contains the second solvent, step (b2) may include a step (b2-3) of drying the second intermediate layer. Drying may be performed simultaneously with step (b2-2), but is preferably performed before step (b2-2). Drying can remove the second solvent from the second intermediate layer.

The second intermediate layer is preferably dried in an atmosphere with a low oxygen concentration. Specifically, the oxygen concentration of the atmosphere is preferably 10% or less, more preferably 5% or less. By performing drying in an atmosphere with a low oxygen concentration in this manner, it is possible to suppress oxygen from being taken into the second intermediate layer. Therefore, since the ultraviolet rays irradiated in step (b2-2) can be suppressed from being absorbed by oxygen, the reaction of the polysilazane compound can proceed stably.

From the viewpoint of drying in an atmosphere with a low oxygen concentration, it is preferable to dry the second intermediate layer in an inert gas atmosphere. Examples of the inert gas include nitrogen, helium, neon, argon, etc. Among them, nitrogen is preferred. Moreover, one type of inert gas may be used alone, or two or more types may be used in any combination. If an inert gas is used, the drying may be carried out, for example, in a drying chamber where the inert gas is supplied and exhausted. Further, heating may be performed during drying.

[5.3. Step (b2-2): Irradiation of the second intermediate layer with ultraviolet rays]
Step (b2) includes a step (b2-2) of irradiating the second intermediate layer with ultraviolet rays after obtaining the second intermediate layer in step (b2-1). By irradiating the second intermediate layer with ultraviolet rays, the polysilazane compound contained in the second intermediate layer reacts, and a second sealing layer containing silicon nitride is obtained.

As the ultraviolet light, light with a wavelength of 1 nm to 380 nm can be used. Among these, it is preferable to use vacuum ultraviolet rays with a wavelength of 100 nm to 200 nm. By irradiating with vacuum ultraviolet rays, the modification reaction of the polysilazane compound can proceed in a short time, so that damage to the element portion and the first sealing layer due to ultraviolet rays can be suppressed. Examples of vacuum ultraviolet light sources include rare gas excimer lamps. Among them, the Xe excimer lamp has excellent luminous efficiency because it emits ultraviolet light with a short wavelength of 172 nm at a single wavelength.

The irradiation intensity of ultraviolet rays can be appropriately adjusted within a range in which a desired second sealing layer can be obtained. To give a specific range, the irradiation intensity is preferably 10 mW/cm ² or more, more preferably 100 mW/cm ² or more, and preferably 300 mW/cm ² or less, more preferably 200 mW/cm ² or less. Among these, step (b2-2) preferably includes UV irradiation at least once at a maximum irradiation intensity of 100 mW/cm ² to 200 mW/cm ² . By irradiating ultraviolet rays at such an irradiation intensity, the modification reaction of the polysilazane compound can proceed in a short time, and damage to the element portion and the first sealing layer due to ultraviolet rays can be suppressed.

The irradiation time of ultraviolet rays can be appropriately adjusted within a range in which a desired second sealing layer can be obtained. Specifically, the irradiation time is preferably 0.1 seconds or more, more preferably 0.5 seconds or more, preferably 10 minutes or less, more preferably 3 minutes or less, and even more preferably 1 minute or less. It is. Irradiation of ultraviolet rays for such an irradiation time allows the modification reaction of the polysilazane compound to proceed sufficiently, reducing variations in sealing ability and preventing damage caused by ultraviolet rays to the element part and the first sealing layer. can be suppressed.

It is preferable that the ultraviolet ray irradiation is performed in an atmosphere with a low oxygen concentration. The specific oxygen concentration of the atmosphere is preferably 500 ppm or more, more preferably 1000 ppm or more, and preferably 10000 ppm or less, more preferably 5000 ppm or less. The unit "ppm" mentioned above is based on mass. When the oxygen concentration of the atmosphere in which ultraviolet rays are irradiated is within the above range, the modification reaction of the polysilazane compound can be effectively promoted, and the sealing ability of the resulting second sealing layer can be improved.

From the viewpoint of performing ultraviolet irradiation in an atmosphere with a low oxygen concentration, the second intermediate layer is preferably irradiated with ultraviolet rays under an inert gas atmosphere. Examples of the inert gas include nitrogen, helium, neon, argon, etc. Among them, nitrogen is preferred. Moreover, one type of inert gas may be used alone, or two or more types may be used in any combination. When using an inert gas, the ultraviolet irradiation may be performed, for example, in a processing chamber into which the inert gas is supplied and exhausted. At this time, in order to adjust the oxygen concentration in the atmosphere, the flow rates of the oxygen gas and inert gas introduced into the processing chamber may be adjusted.

The thickness of the second sealing layer obtained is preferably 1 nm or more, more preferably 10 nm or more, and preferably 100 μm or less, more preferably 10 μm or less, particularly preferably 1 μm or less. When the thickness of the second sealing layer is equal to or greater than the lower limit, moisture infiltration can be effectively suppressed. Moreover, when the thickness of the second sealing layer is equal to or less than the upper limit value, it is possible to reduce the thickness of the device structure.

[6. Manufactured device structure]
According to the embodiment described above, as shown in FIG. 3, a device structure 10 is manufactured that includes a composite layer 100 that includes a base material 110 and an element section 120, and a sealing layer 200 that seals the element section 120. can.

The sealing layer 200 of the manufactured device structure 10 includes a first sealing layer 210 and a second sealing layer 220. The second sealing layer 220 includes silicon nitride produced by a modification reaction of a polysilazane compound. In general, silicon nitride tends to generate stress at high temperatures and is highly brittle, so layers containing silicon nitride tend to crack in high environments. However, since the sealing layer 200 of the device structure 10 manufactured in this embodiment includes the first sealing layer 210 in combination with the second sealing layer 220, the cracks described above can be suppressed. For example, when the device is left in an environment with a temperature of 60° C. and a humidity of 90% RH, the generation of cracks can be suppressed.

The present inventor conjectures the mechanism by which the above-mentioned hardening is achieved by suppressing cracks as described above. However, the technical scope of the present invention is not limited by the following mechanism.
When placed in a high temperature environment, stress is generated in the second sealing layer 220. Silicon nitride included in the second sealing layer 220 tends to generate large stress at high temperatures. Additionally, silicon nitride is generally highly brittle. Therefore, the second sealing layer 220 containing silicon nitride is likely to crack due to the stress. In particular, when the second sealing layer 220 is thick, stress tends to increase due to warpage, and cracks are more likely to occur. However, since the sealing layer 200 includes the first sealing layer 210 in combination with the second sealing layer 220, the stress generated in the second sealing layer 220 is absorbed by the thermoplastic elastomer contained in the first sealing layer 210. can be absorbed into. Therefore, accumulation or concentration of large stress is less likely to occur in the first sealing layer 210, so that the occurrence of cracks in the first sealing layer 210 can be suppressed.

In the device structure 10 described above, since the element section 120 is sealed by the sealing layer 200, moisture intrusion into the element section 120 can be suppressed. Therefore, deterioration of the element section 120 due to moisture can be suppressed. For example, when the element section 120 is an organic electroluminescent element section as shown in the above-described embodiment, the generation of dark spots due to moisture intrusion into the element section 120 can be suppressed. A "dark spot" refers to a dark-looking area that may appear due to deterioration of the organic material of the organic electroluminescent element, causing a portion of the organic electroluminescent element to fail to emit light.

In the manufacturing method described above, both the step (b1) of forming the first sealing layer 210 and the step (b2) of forming the second sealing layer 220 can be performed in an atmospheric pressure environment. can. Therefore, since large and complicated manufacturing equipment is not required, the device structure 10 can be manufactured at low cost. In addition, especially when forming the first intermediate layer and the second intermediate layer by a coating method, it is possible to form the layers by a wet process, so deterioration of the element part 120 due to particles such as plasma dust can be suppressed. .

[7. Example of change]
The present invention is not limited to what has been described in the embodiments described above, and may be implemented with further changes.

In the embodiment described above, one first sealing layer 210 and one second sealing layer 220 are formed by performing the step (b) including one step (b1) and one step (b2). Although the example in which the sealing layer 200 having the above-mentioned sealing layer 200 is formed has been described, the number of the first sealing layer and the second sealing layer may be two or more. Therefore, the step (b) of forming the sealing layer may include the step (b1) of forming the first sealing layer twice or more, and the step (b2) of forming the second sealing layer twice. It may be included more than once.

FIG. 4 is a cross-sectional view schematically showing a device structure 20 manufactured by a manufacturing method according to another embodiment of the present invention. In FIG. 4, the same portions as those shown in FIGS. 1 to 3 will be described with the same reference numerals as shown in FIGS. 1 to 3. For example, as shown in FIG. 4, the device structure 20 includes a sealing layer 300 including a second sealing layer 320, a first sealing layer 210, and a second sealing layer 220 in this order in the thickness direction. Good too. Such a sealing layer 300 can be formed by step (b) including performing step (b2), step (b1), and step (b2) in this order.

As in this embodiment, step (b) preferably includes performing step (b1) and step (b2) in this order. In the sealing layer 300 formed by such process (b), the second sealing layer 220 may be formed outside the first sealing layer 210. Therefore, since the second sealing layer 220 can suppress the infiltration of moisture into the first sealing layer 210, when the first sealing layer 210 contains hygroscopic particles, the moisture absorption ability of the hygroscopic particles is reduced. Can be suppressed.

For example, a method for manufacturing a device structure may include a step of forming an arbitrary layer. Therefore, the method for manufacturing a device structure may include the step of forming an arbitrary layer between the element section and the sealing layer. Further, the method for manufacturing a device structure may include a step of forming an arbitrary layer covering the sealing part. To give a specific example, when the device structure is a display device including an organic electroluminescent element section, the method for manufacturing the device structure includes forming a circular layer on the sealing layer via an adhesive as necessary. The method may include a step of providing a layer of a polarizing plate.

However, even if an arbitrary layer is formed, it is preferable that the arbitrary layer is not formed between the first sealing layer and the second sealing layer. When the first sealing layer and the second sealing layer are in direct contact with each other without intervening any layer, the stress of the second sealing layer cannot be effectively absorbed by the first sealing layer. Therefore, cracks can be effectively suppressed.

The device structure 10 including the organic electroluminescent element portion as the element portion 120 as in the embodiment described above can be used, for example, as a display device, a lighting device, or the like. However, device structures are not limited to these devices. Device structures can include a wide variety of devices that include component parts and assemblies that are part of the device. Among them, since the sealing layer of the device structure described above has excellent transparency, various optical devices and assemblies forming a part of the optical device are preferable as the device structure. Examples of optical devices include liquid crystal displays, touch panels, and organic electroluminescent devices as display devices and light source devices. In particular, it is preferable to use the device structure as a flexible optical device by taking advantage of the excellent flexibility of the organic electroluminescent element portion.

Hereinafter, the present invention will be specifically explained by showing reference examples and comparative examples. The reference example shown below does not match the above-mentioned embodiment in its manufacturing method, but the structure of the manufactured device structure matches the above-mentioned embodiment, so it is effective in suppressing cracks and moisture infiltration. It is possible to prove that.

[Young's modulus, tensile elongation and tan δ of resin]
Young's modulus and tensile elongation of the resin at 23°C were measured according to JIS K7113. The loss tangent tan δ (loss modulus/storage modulus) of the resin at temperatures above 40°C and below 200°C is measured by dynamic viscoelasticity measurement using Hitachi High-Tech Science Co., Ltd. by cutting out a test piece of 10 mm wide x 20 mm long after forming it into a film. Measurement was performed using a device DMS6100.

[Production Example 1: Production of a hydrogenated aromatic vinyl compound-conjugated diene block copolymer modified with a silicon atom-containing polar group]
(P1-1. Production of hydrogenated block copolymer)
Hydrogen of a block copolymer that uses styrene as an aromatic vinyl compound and isoprene as a chain conjugated diene compound and has a triblock structure in which a polymer block [A] is bonded to both ends of a polymer block [B]. A compound (hydrogenated block copolymer) was produced by the following procedure.

256 parts of dehydrated cyclohexane, 25.0 parts of dehydrated styrene, and 0.615 parts of n-dibutyl ether were placed in a reactor equipped with a stirring device and the interior was sufficiently purged with nitrogen, and the n- 1.35 parts of butyllithium (15% cyclohexane solution) was added to initiate polymerization, and the reaction was further carried out at 60° C. for 60 minutes with stirring. The polymerization conversion rate at this point was 99.5% (the polymerization conversion rate was measured by gas chromatography. The same applies below).

Next, 50.0 parts of dehydrated isoprene was added, and stirring was continued for 30 minutes at the same temperature. The polymerization conversion rate at this point was 99%.
Thereafter, 25.0 parts of dehydrated styrene was further added and stirred at the same temperature for 60 minutes. The polymerization conversion rate at this point was approximately 100%.
Next, 0.5 part of isopropyl alcohol was added to the reaction solution to stop the reaction, and a solution (i) containing the block copolymer was obtained.
The weight average molecular weight (Mw) of the block copolymer in the obtained solution (i) was 44,900, and the molecular weight distribution (Mw/Mn) was 1.03 (gel permeation using tetrahydrofuran as a solvent). Measured by chromatography in terms of polystyrene (the same applies hereafter).

Next, the solution (i) was transferred to a pressure-resistant reactor equipped with a stirring device, and the hydrogenation catalyst was added to the solution (i) as a silica-alumina supported nickel catalyst (E22U, nickel loading 60%; manufactured by JGC Chemical Industries, Ltd.). ) and 350 parts of dehydrated cyclohexane were added and mixed. The inside of the reactor was replaced with hydrogen gas, hydrogen was supplied while stirring the solution, and a hydrogenation reaction was carried out at a temperature of 170°C and a pressure of 4.5 MPa for 6 hours to hydrogenate the block copolymer. A solution (iii) containing the copolymer hydride (ii) was obtained. The weight average molecular weight (Mw) of the hydride (ii) in the solution (iii) was 45,100, and the molecular weight distribution (Mw/Mn) was 1.04.

After the hydrogenation reaction was completed, the solution (iii) was filtered to remove the hydrogenation catalyst. Thereafter, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-, which is a phosphorous antioxidant, is added to the filtered solution (iii). Tetrakis-t-butyldibenzo[d,f][1.3.2]dioxaphosphepine (“Sumilyzer (registered trademark) GP” manufactured by Sumitomo Chemical Co., Ltd., hereinafter referred to as “antioxidant A”) 0. A solution (iv) was obtained by adding and dissolving 1.0 part of a xylene solution in which 1 part was dissolved.

Next, the solution (iv) was filtered through a Zeta Plus (registered trademark) filter 30H (manufactured by Cunot Co., Ltd., pore size 0.5 μm to 1 μm), and further filtered through another metal fiber filter (pore size 0.4 μm, manufactured by Nichidai Co., Ltd.). The mixture was successively filtered to remove minute solids. From the filtered solution (iv), using a cylindrical concentration dryer (product name "Contro", manufactured by Hitachi, Ltd.) at a temperature of 260°C and a pressure of 0.001 MPa or less, solvents such as cyclohexane, xylene and other Volatile components were removed. Then, the solid content is extruded into a strand in a molten state from a die directly connected to the concentration dryer, cooled, and cut with a pelletizer to form pellets containing the block copolymer hydride and antioxidant A. (v) 85 parts were obtained. The weight average molecular weight (Mw) of the hydride of the block copolymer (hydrogenated block copolymer) in the obtained pellet (v) was 45,000, and the molecular weight distribution (Mw/Mn) was 1.08. . Further, the hydrogenation rate measured by ¹ H-NMR was 99.9%.

(P1-2. Production of silane-modified product of hydrogenated block copolymer)
To 100 parts of pellets (v) obtained in the above step (P1-1), 2.0 parts of vinyltrimethoxysilane and 0.2 parts of di-t-butyl peroxide were added to obtain a mixture. . This mixture was kneaded using a twin-screw extruder at a barrel temperature of 210° C. and a residence time of 80 seconds to 90 seconds. The kneaded mixture was extruded and cut with a pelletizer to obtain pellets (vi) of a silane-modified hydrogenated block copolymer. A film-like test piece was prepared from this pellet (vi), and the glass transition temperature Tg was evaluated by the tan δ peak of a dynamic viscoelasticity measuring device, and it was found to be 124°C. Moreover, the peak value of tan δ of this pellet (vi) at 40° C. or higher and 200° C. or lower was 1.3. The Young's modulus of this pellet (vi) at 23° C. was 0.5 GPa, and the tensile elongation was 550%. Moreover, the refractive index (n1) of this pellet (vi) measured with an Abbe refractometer was 1.50.

[Production Example 2: Production of resin composition for forming first sealing layer]
(P2-1. Production of hygroscopic particle dispersion)
10 g of zeolite particles (refractive index 1.5) with a primary particle number average particle diameter of 50 nm, 4 g of a dispersant with a basic adsorption group (hydroxyl group-containing carboxylic acid ester, trade name "DISPERBYK108", manufactured by BYK Chemie), and 46 g of cyclohexane. were mixed and dispersed in a bead mill. Through this operation, 17% zeolite dispersion 1 was prepared.

(P2-2. Production of polymer solution)
28 g of pellets (vi) obtained in Production Example 1 and a plasticizer (a plasticizer containing an aliphatic hydrocarbon polymer, product name "Nisseki Polybutene LV-100", manufactured by Nippon Oil Co., Ltd., refractive index 1.50, 12 g (number average molecular weight: 500) was mixed and dissolved in 60 g of cyclohexane. Through this operation, a polymer solution 1 having a solid content of 40% was prepared.

(P2-3. Manufacture of resin composition)
60 g of the zeolite dispersion 1 obtained in the above step (P2-1) and 100 g of the polymer solution 1 obtained in the above step (P2-2) are mixed to prepare a resin solution 1 as a resin composition. I got it. The viscosity of the resulting resin solution 1 was measured. A tuning fork vibratory viscometer "SV-10" manufactured by A&D Co., Ltd. was used to measure the viscosity. The measurement was performed by filling the sample container so that the liquid level of the resin solution 1 was between the reference lines of the sample container, and inserting the vibrator into the resin solution to a specified position. Further, this measurement was performed in an environment of 25°C±2°C. As a result, the viscosity of resin solution 1 was 400 cP.

[Manufacture example 3: Manufacture of multilayer product including organic electroluminescent element portion]
A glass substrate measuring 40 mm in length and 40 mm in width was prepared. On a glass substrate, a transparent electrode layer with a thickness of 100 nm, a hole transport layer with a thickness of 10 nm, a yellow light emitting layer with a thickness of 20 nm, an electron transport layer with a thickness of 15 nm, an electron injection layer with a thickness of 1 nm, and a reflective electrode layer with a thickness of 100 nm, They were formed in this order.

All layers from the hole transport layer to the electron transport layer were formed of organic materials. The materials used to form each layer from the transparent electrode layer to the reflective electrode layer were as follows.
・Transparent electrode layer; tin-doped indium oxide (ITO)
・Hole transport layer; 4,4'-bis[N-(naphthyl)-N-phenylamino]biphenyl (α-NPD)
・Yellow emitting layer; α-NPD with 1.5% by weight of rubrene added
・Electron transport layer; phenanthroline derivative (BCP)
・Electron injection layer; lithium fluoride (LiF)
・Reflecting electrode layer; Al

The transparent electrode layer was formed by a reactive sputtering method using an ITO target.
In addition, to form the hole transport layer to the reflective electrode layer, the base material on which the transparent electrode layer has already been formed is placed in a vacuum evaporation apparatus, and the materials from the hole transport layer to the reflective electrode layer are sequentially heated using a resistance heating method. This was done by vapor deposition.

Through the above operations, a composite material comprising a glass substrate; and an organic electroluminescent element section comprising a transparent electrode layer, a hole transport layer, a yellow light emitting layer, an electron transport layer, an electron injection layer and a reflective electrode layer in this order are obtained. Obtained.

[Comparative example 1]
A SiN layer with a thickness of 200 nm was formed to cover the organic electroluminescent element portion of the multilayer product produced in Production Example 3. The SiN layer was formed by CVD method. As a result, a device structure having a layer structure of "glass base material/organic electroluminescent element section/SiN layer" was obtained.

The device structure described above was left standing in a test environment with a temperature of 60° C. and a humidity of 90% RH. When observed under a microscope after 20 hours, the formation of cracks was confirmed. In addition, a discolored area where the organic electroluminescent element deteriorated due to the infiltration of moisture was observed.

[Reference example 1]
The resin solution 1 obtained in Production Example 2 was applied by screen printing so as to cover the organic electroluminescent element part of the multilayer product produced in Production Example 3, and dried to form a first sealing layer with a thickness of 4 μm. A thermoplastic elastomer layer was formed.

Thereafter, a 200 nm thick SiN layer was formed on the thermoplastic elastomer layer. The SiN layer was formed by CVD method. As a result, a device structure having a layer structure of "glass base material/organic electroluminescent element section/thermoplastic elastomer layer/SiN layer" was obtained.

The device structure described above was left standing in a test environment with a temperature of 60° C. and a humidity of 90% RH. When observed under a microscope after 20 hours, 94 hours, 379 hours, and 500 hours, no crack formation was observed. Further, the area of the discolored portion where the organic electroluminescent element portion deteriorated due to the infiltration of moisture was smaller than that in Comparative Example 1.

[Comparative example 2]
Using the same method as in Comparative Example 1, a 200 nm thick SiN layer was formed to cover the organic electroluminescent element portion of the multilayer product produced in Production Example 3. A 200 nm thick SiN layer was further formed on this SiN layer by CVD. As a result, a device structure having a layer structure of "glass base material/organic electroluminescent element section/SiN layer/SiN layer" was obtained.

The device structure described above was left standing in a test environment with a temperature of 60° C. and a humidity of 90% RH. When observed under a microscope after 20 hours, the formation of cracks was confirmed. The number of cracks formed in Comparative Example 2 was greater than in Comparative Example 1. Furthermore, the area of the discolored part where the organic electroluminescent element part deteriorated due to the infiltration of moisture was larger than that in Comparative Example 1.

[Reference example 2]
A SiN layer with a thickness of 200 nm was formed to cover the organic electroluminescent element portion of the multilayer product produced in Production Example 3. The SiN layer was formed by CVD method.

Thereafter, the resin solution 1 obtained in Production Example 2 was applied onto the SiN layer by screen printing and dried to form a thermoplastic elastomer layer having a thickness of 4 μm as a first sealing layer.

Thereafter, a 200 nm thick SiN layer was formed on the thermoplastic elastomer layer. The SiN layer was formed by CVD method. As a result, a device structure having a layer structure of "glass base material/organic electroluminescent element section/SiN layer/thermoplastic elastomer layer/SiN layer" was obtained.

The device structure described above was left standing in a test environment with a temperature of 60° C. and a humidity of 90% RH. When observed under a microscope after 20 hours, 94 hours, 379 hours, and 500 hours, no crack formation was observed. Further, the area of the discolored portion where the organic electroluminescent element portion deteriorated due to the infiltration of moisture was smaller than that in Reference Example 1.

[result]
A table showing the results of the above reference examples and comparative examples is shown in FIG. In the table shown in FIG. 5, the numerical values in the first row represent the elapsed time from the start of standing at the time of observation. Furthermore, the photographs shown in the table shown in FIG. 5 represent microscopic photographs of the device structures observed at each observation time point.

In Reference Examples 1 and 2, the sealing layer includes a combination of a thermoplastic elastomer layer corresponding to the first sealing layer and a SiN layer corresponding to the second sealing layer. In these Reference Examples 1 and 2, no cracks were generated, and the organic electroluminescent element portion suffered little deterioration due to moisture.

On the other hand, in Comparative Examples 1 and 2, the sealing portion consists of only the SiN layer. In these Comparative Examples 1 and 2, cracks occurred in the SiN layer at an early stage. Furthermore, the organic electroluminescent element portion is significantly deteriorated by moisture.

From the above results, the sealing layer containing a combination of the first sealing layer and the second sealing layer can suppress cracks in the second sealing layer as a SiN layer, and also suppress moisture intrusion. It was confirmed that it can be done. Since the device structures obtained in Reference Examples 1 and 2 can also be obtained in the embodiments described above, it can be understood that the same effects as in Reference Examples 1 and 2 can be obtained according to the manufacturing method of the present invention. .

10 Device structure 20 Device structure 100 Composite layer 110 Base material 110U Surface of base material 120 Element part 120U Surface of element part 121 First electrode layer 122 Light emitting layer 123 Second electrode layer 200 Sealing layer 210 First sealing Layer 210U Surface of first sealing layer 220 Second sealing layer 300 Sealing layer 320 Second sealing layer

Claims (4)

Step (a) of preparing a multi-layered product comprising a base material and an element section provided on the base material;
A method for manufacturing a device structure, comprising a step (b) of forming a sealing layer for sealing the element part,
The step (b) of forming the sealing layer includes a step (b1) of forming a first sealing layer, and a step (b2) of forming a second sealing layer,
The step (b1) of forming the first sealing layer includes a step (b1-1) of forming a first intermediate layer containing a thermoplastic elastomer and a solvent, and a step (b1-2) of drying the first intermediate layer. ) and,
The step (b2) of forming the second sealing layer includes a step (b2-1) of forming a second intermediate layer containing a polysilazane compound, and a step (b2-2) of irradiating the second intermediate layer with ultraviolet rays. and,
The thermoplastic elastomer is selected from the group consisting of a hydrogenated aromatic vinyl compound-conjugated diene block copolymer, and a hydrogenated aromatic vinyl compound-conjugated diene block copolymer modified with a silicon atom-containing polar group. one or more types of
The step (b2-1) includes applying a liquid composition containing the polysilazane compound,
The method for manufacturing a device structure, wherein the thermoplastic elastomer has a Young's modulus of 0.001 to 0.5 GPa at 23°C and a tensile elongation of 550 to 1000%. The method for manufacturing a device structure according to claim 1, wherein the step (b1-1) includes applying a resin composition containing the thermoplastic elastomer and the solvent. The method for manufacturing a device structure according to claim 1 or 2, wherein step (b) includes performing the step (b1) and the step (b2) in this order. The method for manufacturing a device structure according to any one of claims 1 to 3, wherein the element section is an organic electroluminescent element section.

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