JP6840257B2 - Image display device encapsulant and image display device encapsulation sheet - Google Patents

Description

The present invention relates to an image display device sealing material and an image display device sealing sheet.

As an image display device including an optical element, for example, a liquid crystal display, an organic EL display, and the like are known. In such an image display device, the optical element is sealed with a sealing member in order to prevent the optical element from deteriorating due to moisture in the atmosphere or the like.

The sealing member is formed, for example, by embedding an optical element in the sealing composition and then curing the sealing composition. Therefore, various compositions of sealing compositions have been studied in order to impart required performance to the sealing member according to various uses.

For example, it contains a bisphenol type epoxy resin having a weight average molecular weight of 3 × 10 ³ to 1 × 10 ⁴ , a phenol type epoxy resin having a weight average molecular weight of 200 to 800, a curing accelerator, and a silane coupling agent. A sealing composition has been proposed (see, for example, Patent Document 1).

International Publication No. 2010/11706

However, when the sealing member formed from the sealing composition described in Patent Document 1 is used for, for example, a touch panel of an organic EL display, the dielectric constant is high, so that the touch panel is caused by noise caused by the sealing member. May cause malfunction. Further, in such an application, the sealing member needs to be transparent.

The present invention provides an image display device encapsulant and an image display device encapsulation sheet capable of forming a sealing member having a relatively low dielectric constant and ensuring transparency.

The present invention [1] contains a resin component and a curing agent, and the resin component is a bisphenol skeleton-containing phenoxy resin having a weight average molecular weight of 10,000 or more and 100,000 or less, and a weight average molecular weight of 180. An alicyclic skeleton-containing epoxy resin having a weight average molecular weight of 790 or less, a styrene-based oligomer having a weight average molecular weight of 750 or more and 4000 or less, a weight average molecular weight of 500 or more and less than 10,000, and a solubility parameter of 8.9 (cal / cal /). cm ³ ) Contains an image display device encapsulant containing a non-styrene oligomer of ^{1/2 or more.}

In the present invention [2], the non-styrene oligomer is an aliphatic hydrocarbon resin and / or a terpene phenol resin having a ^{solubility parameter of 8.9 (cal / cm 3} ) ^{1/2 or more.} Contains the image display device encapsulant described in 1.

The present invention [3] includes the image display device encapsulant according to the above [1] or [2], wherein the content ratio of the non-styrene oligomer in the resin component is 10% by mass or more. ..

In the present invention [4], the image display device seal according to any one of the above [1] to [3], wherein the content ratio of the non-styrene oligomer to the styrene oligomer is 0.60 or more. Contains stop material.

In the present invention [5], the image display device encapsulant according to any one of the above [1] to [4], wherein the content ratio of the styrene-based oligomer in the resin component exceeds 10% by mass. Includes.

The image display device according to any one of the above [1] to [5], wherein the content ratio of the alicyclic skeleton-containing epoxy resin in the resin component is less than 40% by mass in the resin component of the present invention [6]. Contains encapsulant.

The present invention [7] includes an image display device sealing sheet having a sealing layer made of the image display device sealing material according to any one of the above [1] to [6].

According to the image display device encapsulant and the image display device encapsulation sheet of the present invention, since the solubility parameter of the non-styrene oligomer is equal to or higher than the above lower limit, the bisphenol skeleton-containing phenoxy resin, the alicyclic skeleton-containing epoxy resin, and the epoxy resin are used. The styrene-based oligomer and the non-styrene-based oligomer can be compatible with each other. Therefore, the resin component can contain a styrene-based oligomer and a non-styrene-based oligomer, and a seal member having a relatively low dielectric constant and ensuring transparency can be formed.

FIG. 1 is a side sectional view of the sealing sheet as an embodiment of the image display device sealing sheet of the present invention. FIG. 2 is a side sectional view of an organic EL display with a touch sensor as an embodiment (a mode having an in-cell structure or an on-cell structure) of an image display device including a sealing member formed from the sealing layer shown in FIG. .. FIG. 3A is an explanatory diagram for explaining one embodiment of the method for manufacturing an organic EL display with a touch sensor shown in FIG. 2 (a mode in which a sealing layer on a base film is attached to a substrate), and is an element mounting unit. The process of preparing is shown. FIG. 3B shows a step of attaching the sealing layer to the substrate so that the organic EL element is embedded in the sealing layer, following FIG. 3A. FIG. 3C shows a step of peeling the release film from the sealing layer and attaching the cover glass to the sealing layer, following FIG. 3B. FIG. 4 is an explanatory diagram for explaining another embodiment of the method for manufacturing an organic EL display with a touch sensor (a mode in which a sealing layer on a cover glass or a barrier film is attached to a substrate). FIG. 5 is a side sectional view of an organic EL display with a touch sensor as another embodiment of the image display device (a mode having an out-cell structure).

<Image display device encapsulant>
The image display device sealing material of the present invention (hereinafter referred to as a sealing material) is a sealing resin composition for sealing an optical element included in an image display device described later (sealing resin composition for an image display device). A curable resin composition that forms a seal member, which will be described later, by curing. The sealing material contains a resin component and a curing agent.

(1) Resin component As essential components, the resin component includes _{a bisphenol skeleton-containing phenoxy resin having a weight average molecular weight (M w} ) of 10,000 or more and 100,000 or less, and a weight average molecular weight (M _w ) of 180 or more and 790 or less. The alicyclic skeleton-containing epoxy resin is, _{a styrene-based oligomer having a weight average molecular weight (M w} ) of 750 or more and 4000 or less, a weight average molecular weight (M _w ) of 500 or more and less than 10,000, and a solubility parameter of 8. .9 (cal / cm ³ ) ^{Contains 1/2} or more of the non-styrene oligomer.

(1-1) Bisphenol Skeleton-Containing Phenoxy Resin The bisphenol skeleton-containing phenoxy resin is a high-molecular-weight (M _w : 10,000 or more and 100,000 or less) epoxy resin having a bisphenol skeleton and an epoxy group. The bisphenol skeleton-containing phenoxy resin is solid at room temperature. The "normal temperature solid" means a solid state having no fluidity at normal temperature (23 ° C.), and the "normal temperature liquid" means a liquid state having fluidity at normal temperature (23 ° C.). (The same applies hereinafter).

Since the resin component contains a bisphenol skeleton-containing phenoxy resin, the sheet moldability of the sealing material can be improved, and the moisture permeability of the sealing member (described later) can be reduced.

The weight average molecular weight (M _w ) of the bisphenol skeleton-containing phenoxy resin is 10,000 or more, preferably 20,000 or more, 30,000 or more, 100,000 or less, preferably 90,000 or less. The weight average molecular weight (M _w ) can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance (the same applies hereinafter).

The epoxy equivalent of the bisphenol skeleton-containing phenoxy resin is, for example, 2,000 g / eq. As mentioned above, preferably 4,000 g / eq. As mentioned above, more preferably, 7,000 g / eq. As described above, for example, 20,000 g / eq. Hereinafter, preferably, 16,000 g / eq. It is as follows. Epoxy equivalents can be measured according to JIS K7236: 2001 (the same shall apply hereinafter).

The bisphenol skeleton-containing phenoxy resin is compatible with non-styrene oligomers. The solubility parameter (hereinafter referred to as SP value) of the bisphenol skeleton-containing phenoxy resin is, for example, 11.5 (cal / cm ³ ) ^1/2 or more and 13.0 (cal / cm ³ ) ^1/2 or less. The SP value can be calculated by the calculation software CHEOPS (version 4.0) of Million Zillion Software Co., Ltd. (the same applies hereinafter). The calculation method used in the calculation software is described in Computational Materials Science of Polymers (AA Askadskii, Cambridge Institute Science Pub (2005/12/30)) Chapter XII.

Such a bisphenol skeleton-containing phenoxy resin has, for example, a plurality of bisphenol skeletons and a plurality of epoxy groups (polyfunctional (including bifunctional) type epoxy resin), and preferably has a molecular chain containing a plurality of bisphenol skeletons. And an epoxy group bonded to both ends of the molecular chain (bifunctional epoxy resin). The bisphenol skeleton-containing phenoxy resin does not contain a biphenyl skeleton.

Examples of the bisphenol skeleton-containing phenoxy resin include bisphenol skeleton-containing phenoxy resins containing structural units I to III represented by the following formula (1). The bisphenol skeleton-containing phenoxy resin containing the structural units I to III has a molecular chain containing a plurality of bisphenol skeletons and a glycidyl ether unit bonded to both ends of the molecular chain.
Equation (1)

[In formula (1), I, II and III are constituent units, each of I and III is a terminal unit, and II is a repeating unit. R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. ]
The bisphenol skeleton-containing phenoxy resin containing the structural units I to III represented by the above formula (1) is preferably used alone.

^{Examples of the alkyl group represented by R 1 in the} above formula (1) include a linear alkyl group having 1 to 6 carbon atoms (for example, methyl, ethyl, propyl, butyl, pentyl, hexyl) and a branch having 3 to 6 carbon atoms. Alkyl groups (eg, isopropyl, isobutyl, tert-butyl, etc.) and the like can be mentioned. ^{Among R 1} of the above formula (1), a hydrogen atom is preferably mentioned. A plurality of R ¹ in the formula (1) may be the same as each other, but may be different from each other, preferably the same.

Examples of the hydrocarbon group represented by ^{R 2 in the} above formula (1) include an alkyl group having 1 to 6 carbon atoms and an aryl group having 6 to 12 carbon atoms (for example, phenyl, trill, xsilyl, etc.) similar to those in ^{R 1 above.} ) And so on. ^{Among R 2} of the above formula (1), a hydrogen atom and a methyl group are preferably mentioned. A plurality of R ² in the formula (1) may be identical to each other, may be different from each other.

Further, the bisphenol skeleton-containing phenoxy resin containing the structural units I to III represented by the above formula (1) contains a plurality of structural units II. Two combinations of R ² of structural unit II represented by the above formula (1) may be identical in all the structural units II, a plurality of structural units II are different configurations combination of two R ² s together Unit II may be included. The bisphenol skeleton-containing phenoxy resin represented by the above formula (1) preferably has ^{a structural unit II in which two} R 2s are methyl groups (bisphenol A skeleton) and a structural unit II in which ^{two R 2s are hydrogen atoms.} It also has a bisphenol F skeleton).

The bisphenol skeleton phenoxy resin containing the structural units I to III represented by the above formula (1) is, for example, a bisphenol compound (for example, bisphenol A, bisphenol F, 4,4'-(1-phenylethylidene) bisphenol, 4,4. It is a copolymer (reactant) of'-(1-phenylpropylidene) bisphenol, etc.) and epichlorohydrin.
The bisphenol compound can be used alone or in combination of two or more. Among the bisphenol compounds, bisphenol A and bisphenol F are preferably mentioned, and bisphenol A and bisphenol F are more preferably used in combination.

Further, the bisphenol skeleton phenoxy resin containing the structural units I to III represented by the above formula (1) may contain other structural units in addition to the structural units I to III. Other building blocks include, for example, a polyol unit derived from a divalent or higher valent polyol (eg, glycol, benzenediol, etc.).

As the bisphenol skeleton phenoxy resin containing the structural units I to III represented by the above formula (1), a commercially available product can also be used. As a commercially available bisphenol skeleton phenoxy resin containing the structural units I to III represented by the above formula (1), for example, JER-4275 (manufactured by Mitsubishi Chemical Corporation, weight average molecular weight: about 60,000, epoxy equivalent: 8,400). -9,200 g / eq.), JER-1256 (manufactured by Mitsubishi Chemical Corporation, weight average molecular weight: about 90,000, epoxy equivalent: 7,500-8,500 g / eq.).

In the resin component, the content ratio of the bisphenol skeleton-containing phenoxy resin is, for example, 5% by mass or more, preferably 10% by mass or more, for example, 50% by mass or less, preferably 40% by mass or less.

When the content ratio of the bisphenol skeleton-containing phenoxy resin is within the above range, the content ratio of other resin components can be secured, and various properties required for the encapsulant can be secured in a well-balanced manner.

(1-2) Alicyclic Skeleton-Containing Epoxy Resin The alicyclic skeleton-containing epoxy resin is a low molecular weight (M _w : 180 or more and 790 or less) epoxy resin having at least an epoxy group and an aliphatic ring (alicyclic skeleton). is there. The alicyclic skeleton-containing epoxy resin is a room temperature liquid. The alicyclic skeleton-containing epoxy resin does not have a bisphenol skeleton and a biphenyl skeleton.

Since the resin component contains an alicyclic skeleton-containing epoxy resin, the haze value of the sealing member (described later) can be reduced as compared with the case where the resin component contains an aromatic ring skeleton-containing epoxy resin, and the transparency of the sealing member (described later) can be reduced. It is possible to improve the moisture permeability of the seal member (described later) and reduce the moisture permeability.

The weight average molecular weight of the alicyclic skeleton-containing epoxy resin is 180 or more, 790 or less, preferably 500 or less. The epoxy equivalent in the alicyclic skeleton-containing epoxy resin is, for example, 90 g / eq. As mentioned above, preferably 100 g / eq. As described above, for example, 190 g / eq. Hereinafter, preferably, 200 g / eq. It is as follows.

The alicyclic skeleton-containing epoxy resin is compatible with the non-styrene oligomer and has the same SP value as the non-styrene oligomer (for example, 9.0 (cal / cm ^{3 ) 1/2} or more and 11.5 (cal). / Cm ³ ) ^1/2 or less).

The alicyclic skeleton-containing epoxy resin has, for example, a plurality of aliphatic rings and a plurality of epoxy groups (polyfunctional (including bifunctional) type epoxy resin).

The alicyclic skeleton-containing epoxy resin contains, for example, an epoxy group having an epoxy group composed of two adjacent carbon atoms forming an aliphatic ring and one oxygen atom bonded to those two carbon atoms. Examples thereof include an alicyclic skeleton epoxy resin (bifunctional epoxy resin) and a glycidyl ether-containing alicyclic skeleton epoxy resin having a plurality of glycidyl ether units bonded to an aliphatic ring (polyfunctional epoxy resin). The alicyclic skeleton-containing epoxy resin can be used alone or in combination of two or more.

Examples of the epoxy group-containing alicyclic epoxy resin include an alicyclic epoxy compound having a cycloalkene oxide structure.

Examples of the alicyclic epoxy compound having a cycloalkene oxide structure include an epoxy compound having an epoxycyclohexane structure represented by the following formula (2) (hereinafter referred to as an ECH structure-containing epoxy compound) and a modified product thereof. Be done.
Equation (2)

[In formula (2), X represents a single bond or a linking group (a divalent group having one or more atoms). A substituent such as an alkyl group may be bonded to the carbon atom constituting the cyclohexane ring. ]
The ECH structure-containing epoxy compound represented by the above formula (2) has an epoxycyclohexane structure (epoxycyclohexyl group) at both ends of the molecule, and the two epoxycyclohexyl groups are directly bonded by a single bond or have a linking group. Join through. The epoxycyclohexyl group is a functional group containing a cyclohexane ring, two adjacent carbon atoms forming the cyclohexane ring, and an epoxy group composed of one oxygen atom bonded to the two carbon atoms. Is.

When X is a single bond in the above formula (2), a carbon atom forming a cyclohexane ring of an epoxycyclohexyl group located at one end and a carbon atom forming a cyclohexane ring of an epoxycyclohexyl group located at the other end. And are directly connected.

Examples of the linking group represented by X in the above formula (2) include a divalent hydrocarbon group, a carbonyl group, an ether group, a thioether group, an ester group, a carbonate group, an amide group, and a group in which these are linked. Be done.

As the divalent hydrocarbon group, for example, a linear or branched alkylene group having 1 to 18 carbon atoms (for example, methylene group, methylmethylene group, dimethylmethylene group, ethylene group, propylene group, trimethylene group, etc.), Cycloalkylene group (eg, 1,2-cyclopentylene group, 1,3-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclohexylene group, 1,4-cyclohexylene group, etc.), Cycloalkylidene groups (eg, cyclopentylidene group, cyclohexylidene group, etc.) and the like can be mentioned.

Among the linking groups represented by X in the above formula (2), a linking group containing an oxygen atom is preferably mentioned from the viewpoint of adhesiveness of the sealing member (described later), and more preferably, a carbonyl group, an ether group, and the like. Examples thereof include an ester group and a carbonate group, and particularly preferably an ester group.

Examples of the alkyl group that can be bonded to the carbon atom constituting the cyclohexane ring include an alkyl group similar to ^{R 1 of the above formula (1).} Further, preferably, a substituent is not bonded (unsubstituted) to the carbon atom constituting the cyclohexane ring, and a hydrogen atom is bonded.

Examples of the ECH structure-containing epoxy compound represented by the above formula (2) include (3,3', 4,4'-diepoxy) bicyclohexyl, bis (3,4-epoxycyclohexylmethyl) ether, and 1,2-bis. (3,4-Epoxycyclohexane-1-yl) ethane, 1,2-epoxy-1,2-bis (3,4-epoxycyclohexane-1-yl) ethane, 2,2-bis (3,4-epoxy) cyclohexane-1-yl) propane, 3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexane carboxylate, .epsilon.-caprolactone-modified 3 ', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane key sheet rate Can be mentioned.

As the ECH structure-containing epoxy compound represented by the above formula (2), a commercially available product can also be used. Examples of commercially available products of the ECH structure-containing epoxy compound represented by the above formula (2) include celoxide 8000, celoxide 2021P (epoxy equivalent 128 to 145 g / eq.), Celoxide 2081 (all manufactured by Daicel) and the like.

Examples of the glycidyl ether-containing alicyclic skeleton epoxy resin include a dicyclopentadiene type epoxy resin represented by the following formula (3) (hereinafter referred to as DCPD type epoxy resin).
Equation (3)

[In the formula (3), a substituent such as an alkyl group may be bonded to the carbon atom constituting the aliphatic ring derived from dicyclopentadiene. ]
The DCPD type epoxy resin represented by the above formula (3) has an aliphatic ring derived from dicyclopentadiene and two glycidyl ether units bonded to the aliphatic ring.

Examples of the alkyl group that can be bonded to the carbon atom constituting the aliphatic ring derived from dicyclopentadiene include an alkyl group similar to ^{R 1 of the above formula (1).} Further, the carbon atom constituting the aliphatic ring derived from dicyclopentadiene is preferably not bonded to a substituent (unsubstituted), and a hydrogen atom is bonded to the carbon atom.

As the DCPD type epoxy resin represented by the above formula (3), a commercially available product can also be used. Examples of commercially available products of the DCPD type epoxy resin represented by the above formula (3) include EP-4088S (manufactured by ADEKA Corporation, epoxy equivalent 170 g / eq.).

Such an alicyclic skeleton-containing epoxy resin can be used alone or in combination of two or more, but is preferably used alone. That is, as the alicyclic skeleton-containing epoxy resin, either one of the ECH structure-containing epoxy compound represented by the above formula (2) and the DCPD type epoxy resin represented by the above formula (3) is preferably used alone.

When the alicyclic skeleton-containing epoxy resin is the single use of the ECH structure-containing epoxy compound represented by the above formula (2), the alicyclic skeleton-containing epoxy resin is the single use of the DCPD type epoxy resin represented by the above formula (3). It is possible to improve the curing speed of the encapsulant as compared with a certain case.

In the resin component, the content ratio of the alicyclic skeleton-containing epoxy resin is, for example, 10% by mass or more, preferably 20% by mass or more, for example, 50% by mass or less, preferably less than 40% by mass, more preferably 35. It is mass% or less.

When the content ratio of the alicyclic skeleton-containing epoxy resin is within the above range, the haze value of the sealing member (described later) can be reliably reduced. When the content ratio of the alicyclic skeleton-containing epoxy resin is not more than the above upper limit, the content ratio of other resin components can be secured, and various properties required for the encapsulant can be secured in a more balanced manner.

(1-3) Styrene-based oligomer The styrene-based oligomer is a polymer in which vinyl groups of a plurality of styrene skeletons are bonded to each other, and has a plurality of styrene units derived from the plurality of styrene skeletons. The styrene-based oligomer is a solid at room temperature. The styrene-based oligomer does not contain a high molecular weight styrene-butadiene-styrene block copolymer (SBS rubber) having a weight average molecular weight (M _{w) of more than 10,000.}

The weight average molecular weight (M _w ) of the styrene-based oligomer is 750 or more, preferably 900 or more and 4000 or less, preferably 3800 or less. The number average molecular weight (M _n ) of the styrene-based oligomer is, for example, 500 or more, preferably 600 or more, more preferably 700 or more, for example 2500 or less, preferably 2000 or less, still more preferably 1500 or less. ..

The weight average molecular weight / number average molecular weight (M _w / M _n ) is, for example, 1.1 or more, preferably 1.2 or more, more preferably 1.3 or more, for example 2.5 or less. Is 2.0 or less, more preferably 1.9 or less.

The styrene-based oligomer is compatible with the non-styrene-based oligomer and has the same SP value as the non-styrene-based oligomer (for example, 8.5 (cal / cm ³ ) ^1/2 or more and 9.1 (cal / cm ^3). ) ^1/2 or less).

Examples of the styrene-based oligomer include a homopolymer of a styrene skeleton-containing monomer and a copolymer of a styrene skeleton-containing monomer and another polymerizable monomer. The styrene-based oligomer can be used alone or in combination of two or more.

Examples of the styrene skeleton-containing monomer include styrene, α-methylstyrene, vinyltoluene, isopropanoltoluene, and the like, and isopropanoltoluene is preferable. The styrene skeleton-containing monomer can be used alone or in combination of two or more.

The other polymerizable monomer is a monomer copolymerizable with the styrene skeleton-containing monomer and has, for example, an ethylenically unsaturated double bond. Other polymerizable monomers include, for example, unsaturated aliphatic monomers having 2 to 10 carbon atoms (for example, ethylene, propylene, butene, isobutene, butadiene, penten, pentadiene, isoprene, hexadiene, methylbutene, etc.) and 5 to 5 carbon atoms. Purification and decomposition of 20 unsaturated aliphatic monomers (eg, cyclopentadiene, dicyclopentadiene, etc.), α, β-unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, etc.), (meth) acrylates, petroleum. like C ₅ fraction obtained by such. The C5 fraction usually has a boiling range of -15 ° C to + 45 ° C under normal pressure, and is 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-pentene, isoprene. , 1,3-Pentane, cyclopentadiene and the like. Other polymerizable monomers can be used alone or in combination of two or more.

In the copolymer of the styrene skeleton-containing monomer and other polymerizable monomer, the content ratio of the structural unit derived from the styrene skeleton-containing monomer is, for example, 50% by mass or more, preferably 80% by mass or more, for example, 99% by mass. % Or less, preferably 95% by mass or less.

Further, among the styrene-based oligomers, a homopolymer of a styrene skeleton-containing monomer is preferable. That is, the styrene-based oligomer preferably contains a homopolymer of a styrene skeleton-containing monomer, and more preferably a homopolymer of a styrene skeleton-containing monomer is used alone.

When the styrene-based oligomer contains a homopolymer of a styrene skeleton-containing monomer (particularly, when a homopolymer of a styrene skeleton-containing monomer is used alone), ensure that the moisture permeability of the sealing member (described later) is reduced. Can be done.

In the resin component, the content ratio of the styrene-based oligomer is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably more than 10% by mass, and particularly preferably. , 15% by mass or more, for example, 40% by mass or less, preferably 25% by mass or less.

When the content ratio of the styrene-based oligomer is not more than the above lower limit, the haze value of the sealing member (described later) can be surely reduced. When the content ratio of the styrene-based oligomer is not more than the above upper limit, the content ratio of other resin components can be secured, and various properties required for the encapsulant can be secured in a more balanced manner.

(1-4) Non-Styrene Oligomer The non-styrene oligomer has a weight average molecular weight of 500 or more and less than 10,000, and an SP value of 8.9 (cal / cm ³ ) ^1/2 or more. Non-styrene oligomers do not have a styrene skeleton. The non-styrene oligomer contains a ring skeleton (aliphatic ring and / or aromatic ring) and does not contain an epoxy group. The non-styrene oligomer is a solid at room temperature.

Since the resin component contains a styrene-based oligomer and a non-styrene-based oligomer, the haze value of the seal member (described later) can be reduced while the dielectric constant of the seal member (described later) can be reduced.

The SP value of the non-styrene oligomer is 8.9 (cal / cm ³ ) ^1/2 or more, for example, 11.5 (cal / cm ³ ) ^1/2 or less, preferably 11.5 (cal / cm ^3). ) ^{Less than 1/2} , more preferably 10.0 (cal / cm ³ ) ^1/2 or less.

When the SP value of the non-styrene oligomer is at least the above lower limit, the compatibility with other resin components can be improved, and the sheet moldability of the encapsulant can be improved.

The weight average molecular weight (M _w ) of the non-styrene oligomer is 500 or more and less than 10,000, preferably 4000 or less.

When the weight average molecular weight of the non-styrene oligomer is within the above range, the compatibility with other resin components can be improved.

The softening point of the non-styrene oligomer is, for example, 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, for example, 150 ° C. or lower. The softening point can be measured according to the method described in JIS K2207 (the same applies hereinafter).

When the softening point of the non-styrene oligomer is at least the above lower limit, the moisture permeability of the sealing member (described later) can be reliably reduced.

As the non-styrene oligomer, for example, ^{an aliphatic hydrocarbon resin having an SP value of 8.9 (cal / cm 3} ) ^1/2 or more (hereinafter referred to as an aliphatic hydrocarbon resin (A)) has an SP value of 8.9 (cal / cm 3) or more. ^{Examples thereof include a terpene phenol resin having a value of} 8.9 (cal / cm ³ ) 1/2 or more (hereinafter referred to as a terpene phenol resin (B)). The non-styrene oligomer can be used alone or in combination of two or more.

The aliphatic hydrocarbon resin (A) is an aliphatic hydrocarbon resin whose SP value is within the range of the SP value of the above-mentioned non-styrene-based oligomer, and preferably has an SP value of 9.0 (cal / cm ^3). ) It is an aliphatic hydrocarbon resin that is ^{1/2 or more.} The aliphatic hydrocarbon resin (A) is a flake-like solid at room temperature.

As the aliphatic hydrocarbon resin (A), for example, a petroleum-based hydrocarbon resin (preferably a homopolymer of dicyclopentadiene) containing dicyclopentadiene extracted from the C5 distillate obtained by naphtha decomposition as a main raw material. Examples thereof include an ester-modified hydrocarbon resin into which an ester group has been introduced. The ester-modified hydrocarbon resin is preferably used alone. The ester-modified hydrocarbon resin has an aliphatic ring derived from dicyclopentadiene and an atomic group containing an ester group. Examples of the atomic group containing an ester group include a vinyl acetate unit derived from vinyl acetate.

The range of the weight average molecular weight (Mw) of the ester-modified hydrocarbon resin is the same as the range of the weight average molecular weight (Mw) of the non-styrene oligomer, and is preferably 500 or more and 4000 or less. Range of the softening point of the ester-modified hydrocarbon resin, for example, the same as the range of the softening point of the non-styrenic oligomer described above, preferably less than 80 ° C. or higher 120 ° C..

Saponification value of the ester-modified hydrocarbon resin, for example, at most 100 mg KOH / g or more 200 mg KOH / g. Note that the saponification value can be measured according to the method described in JIS K0070.

As such an ester-modified hydrocarbon resin, a commercially available product can also be used. Examples of commercially available ester-modified hydrocarbon resins include Quintone 1500 and Quintone 1525L (both manufactured by Zeon Corporation).

The terpene phenol resin (B) is a terpene phenol resin whose SP value is within the range of the SP value of the above-mentioned non-styrene oligomer, and preferably has an SP value of 9.3 (cal / cm ³ ) ^1/2. The above is the terpene phenol resin. The terpene phenol resin (B) is a solid at room temperature. The terpene phenol resin (B) is preferably used alone. The terpene phenol resin (B) is a copolymer (reactant) of the terpene compound and the phenol compound. The terpene phenol resin (B) is obtained by reacting a terpene compound and a phenol compound at 20 ° C. to 150 ° C. for 1 to 20 hours in the presence of an acidic catalyst (for example, hydrochloric acid, sulfuric acid, cation exchange resin, etc.). Prepared.

Terpene compound is a compound having a hydrocarbon to the structural unit of isoprene (C 5 _{H 8)} as a main skeleton. Examples of terpene compounds include α-pinene, β-pinene, dipentene, limonene, α-phellandrene, β-pherandrene, α-terpinene, β-terpinene, γ-terpinene, terpinene, milsen, aloosimene, 1,8-. Cineol, 1,4-cineole, α-terpinene, β-terpinene, γ-terpinene, 4-terpinene, sabinene, kanfen, tricyclenene, paramentene-1, paramentene-2, paramentene-3, paramentene-8, paramentadiens , Δ2-Phellandrene, Δ3-Phellandrene, Cariophyllene, Longifolene and the like. The terpene compound can be used alone or in combination of two or more.

Examples of the phenol compound include phenol, cresol, xylenol, propylphenol, nonylphenol, hydroquinone, resorcin, methoxyphenol, bromophenol, bisphenol A, bisphenol F and the like. The phenol compound can be used alone or in combination of two or more. Among the phenol compounds, phenol is preferable.

The range of the weight average molecular weight (Mw) of the terpene phenol resin (B) is the same as the range of the weight average molecular weight (Mw) of the non-styrene oligomer. Range of the softening point of the terpene phenol resin (B), for example, the same as the range of the softening point of the non-styrenic oligomer described above, preferably, 120 ° C. or higher 0.99 ° C. or less.

As such a terpene phenol resin (B), a commercially available product can also be used. Examples of commercially available products of the terpene phenol resin (B) include YS Polystar K-125 (manufactured by Yasuhara Chemical Co., Ltd.).

In the resin component, the content ratio of the non-styrene oligomer is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, for example, 30% by mass or less, preferably 20% by mass. It is as follows.

The content ratio of the non-styrene oligomer to the styrene oligomer is, for example, 0.10 or more, preferably 0.30 or more, more preferably 0.60 or more, for example, 1.5 or less, preferably 1. It is 0 or less.

When the content ratio of the non-styrene oligomer is at least the above lower limit, the haze value of the sealing member (described later) can be reliably reduced. When the content ratio of the non-styrene oligomer is not more than the above upper limit, the content ratio of other resin components can be secured, and various properties required for the encapsulant can be secured in a more balanced manner.

(1-5) Arbitrary Resin Component The resin component can further contain, as an optional component, a bisphenol skeleton-containing epoxy resin having a weight average molecular weight of 800 or more and less than 10,000.

The bisphenol skeleton-containing epoxy resin has a plurality of bisphenol skeletons and a plurality of epoxy groups (polyfunctional (including bifunctional) type epoxy resin) and is solid at room temperature. The bisphenol skeleton-containing epoxy resin has a lower molecular weight than the above-mentioned bisphenol skeleton-containing phenoxy resin and a higher molecular weight than the above-mentioned alicyclic skeleton-containing epoxy resin.

Specifically, the weight average molecular weight (Mw) of the bisphenol skeleton-containing epoxy resin is 800 or more, preferably 900 or more and less than 10,000, preferably 8,000 or less.

The epoxy equivalent in the bisphenol skeleton-containing epoxy resin is, for example, 100 g / eq. As mentioned above, preferably 150 g / eq. As described above, for example, 2,000 g / eq. Hereinafter, preferably 1500 g / eq. It is as follows.

The bisphenol skeleton-containing epoxy resin is compatible with non-styrene oligomers, and the SP value of the bisphenol skeleton-containing epoxy resin is, for example, 11.5 (cal / cm ³ ) ^1/2 or more and 13.0 (cal / cm). ³ ) ^{It is 1/2} or less.

The bisphenol skeleton-containing epoxy resin is, for example, a copolymer of the above bisphenol compound and epichlorohydrin, and comprises a molecular chain containing a plurality of bisphenol skeletons and a glycidyl ether unit bonded to both ends of the molecular chain. Has (bifunctional epoxy resin). Among the bisphenol compounds, bisphenol F is preferably mentioned.

The bisphenol skeleton-containing epoxy resin is contained as an adjustment of the content ratio in the resin component for the purpose of moldability of the sealing member (described later). In the examples described later, the content ratio of the bisphenol skeleton-containing epoxy resin is such that when the content ratios of other resin components are changed, the total of the resin components is 100 parts by mass (that is, the bisphenol skeleton-containing epoxy resin). Content ratio = 100-total content ratio of other resin components).

Specifically, in the resin component, the content ratio of the bisphenol skeleton-containing epoxy resin is, for example, 5% by mass or more, preferably 15% by mass or more, for example, 40% by mass or less, preferably 30% by mass or less. .. When the content ratio of the bisphenol skeleton-containing epoxy resin is within the above range, the moldability of the sealing member (described later) can be improved.

The resin component is a specific resin component (bisphenol skeleton-containing phenoxy resin, alicyclic skeleton-containing epoxy resin, styrene-based oligomer, non-styrene oligomer, bisphenol skeleton-containing epoxy resin) as long as the effect of the present invention is not impaired. ) Other resin components can be contained.

Other resin components include, for example, other epoxy resins (eg, bisphenol skeleton-containing epoxy resins with a weight average molecular weight of less than 800), polyolefins (eg, polyethylene, polybutadiene, etc.), polychloroprenes, polyamides, polyamideimides, polyurethanes, etc. Examples include polyether, polyester, and silicone resin. These other resin components can be used alone or in combination of two or more. In the resin component, the content ratio of the other resin component is, for example, 10% by mass or less, preferably 5% by mass or less.

(2) Curing agent The curing agent polymerizes the resin component to cure the encapsulant. The curing agent is not particularly limited as long as the encapsulant can be cured. As the curing agent, for example, an amine-based curing agent (for example, diethylenetriamine, triethylenetetramine, tri (dimethylaminomethyl) phenol, etc.), an imidazole-based curing agent (for example, 2-methylimidazole, 2-ethyl-4-methylimidazole, etc.), etc. ), Acid anhydride-based curing agents (for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, etc.), thermocation-based curing agents and the like. The curing agent can be used alone or in combination of two or more.

Among the curing agents, a thermocation-based curing agent is preferable. That is, the curing agent preferably contains a thermal cationic curing agent, and preferably the thermal cationic curing agent is used alone. If the curing agent contains a thermal cationic curing agent, the curing speed of the encapsulant can be improved.

The thermocation-based curing agent is a thermoacid generator that generates an acid by heating. The thermal cation-based curing agent may be a compound capable of generating a cation by heating and initiating the polymerization of the above-mentioned (1-1) bisphenol skeleton-containing phenoxy resin and (1-2) alicyclic skeleton-containing epoxy resin. The compound is not particularly limited, but is preferably a compound capable of initiating polymerization at a heat resistant temperature of 120 ° C. or lower for a display element (for example, an organic EL element or the like). As the thermal cationic curing agent, a known cationic polymerization initiator can be used. As the thermal cationic polymerization initiator, for example, _{a sulfonium salt having AsF 6} ⁻ , SbF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , B (C ₆ F ₅ ) ₄ ⁻ , CF ₃ SO ₃ ⁻ as a counter anion, etc. Examples thereof include phosphonium salt, quaternary ammonium salt, diazonium salt and iodonium salt.

Examples of the sulfonium salt include a boron fluoride-based sulfonium salt (for example, triphenylsulfonium tetrafluoride) and an arsenic fluoride-based sulfonium salt (for example, triphenylsulfonium arsenic hexafluoride, tri (4-methoxyphenyl) sulfonium. Arsenic hexafluoride, diphenyl (4-phenylthiophenyl) sulfonium, arsenic hexafluoride, etc.), antimony fluoride-based sulfonium salt (eg, triphenylsulfonium, antimony hexafluoride, etc.), phosphorus-fluorinated sulfonium salt (eg, tri) Phenylsulfoonium hexafluoride phosphate, etc.) and the like.

Examples of the phosphonium salt include antimony pentafluoride-based phosphonium salts (for example, ethyltriphenylphosphonium hexafluoride antimony, tetrabutylphosphonium hexafluoride antimony, etc.).

As the quaternary ammonium salt, for example, an antimony fluoride-based quaternary ammonium salt (for example, N, N-dimethyl-N-benzylanilinium hexafluoride antimony, N, N-dimethyl-N-benzylpyridinium hexafluoride antimony, etc. N, N-dimethyl-N- (4-methoxybenzyl) pyridinium hexafluoride antimony, N, N-diethyl-N- (4-methoxybenzyl) pyridinium hexafluoride antimony, N, N-diethyl-N- (4) −methoxybenzyl) toluidinium hexafluoride antimony, N, N-dimethyl-N- (4-methoxybenzyl) toluidinium hexafluoride antimony, etc.), boron trifluoride quaternary ammonium salt (eg, N, N-diethyl-N) -Benzylanilinium boron trifluoride and the like), organic acid-based quaternary ammonium salts (for example, N, N-diethyl-N-benzylpyridinium trifluoromethanesulfonic acid and the like) and the like.

Examples of the iodonium salt include antimony fluoride iodonium salt (for example, diphenyliodonium hexafluoride antimony), phosphorus fluoride iodonium salt (for example, diphenyliodonium hexafluoride phosphate), and boron trifluoride iodonium salt (for example). , Diphenyliodonium boron trifluoride, etc.).

The thermal cation-based curing agent can be used alone or in combination of two or more.

Among the thermal cation-based curing agents, a quaternary ammonium salt is preferably used, and an antimony pentafluoride quaternary ammonium salt is more preferable.

As such a thermal cationic curing agent, a commercially available product can also be used. Commercially available thermal cation-based curing agents include, for example, CXC-1612, CXC-1733, CXC1821 (all manufactured by King Industries), Sun Aid SI-60, Sun Aid SI-80, Sun Aid SI-B3, Sun Aid SI-B3A, Examples include Sun Aid SI-B4 (both manufactured by Sanshin Chemical Industry Co., Ltd.) and TA-100 (manufactured by Sun Appro Co., Ltd.).

The content ratio of the curing agent is, for example, 0.5 parts by mass or more, preferably 1 part by mass or more, for example, 10 parts by mass or less, preferably 5 parts by mass or less, based on 100 parts by mass of the resin component.

(3) Other Additives The encapsulant may contain a silane coupling agent, a leveling agent and the like as other additives, if necessary.

If the sealing material contains a silane coupling agent, the adhesion of the sealing member (described later) to the substrate (described later) can be improved.

As the silane coupling agent, for example, an epoxy group-containing silane coupling agent (for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltri) Methoxysilane, etc.), amino group-containing silane coupling agents (eg, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyltriethoxysilane, 3-aminopropyltrimethoxysilane, etc.), Methacryloyl group-containing silane coupling agent (eg, γ-methacryloxypropylmethyldimethoxysilane, γ-methacry) Roxypropyltrimethoxysilane, etc.) and the like. The silane coupling agent can be used alone or in combination of two or more.

Among the silane coupling agents, an epoxy group-containing silane coupling agent is preferable, and γ-glycidoxypropyltrimethoxysilane is more preferable.

The content ratio of the silane coupling agent is, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, for example, 30 parts by mass or less, preferably 5 parts by mass with respect to 100 parts by mass of the resin component. It is as follows.

If the encapsulant contains a leveling agent, the surface of the encapsulant can be smoothed when the encapsulant is applied. The content ratio of the leveling agent is, for example, 0.01 part by mass or more, preferably 0.1 part by mass or more, for example, 5.0 parts by mass or less, preferably 1.0 with respect to 100 parts by mass of the resin component. It is less than a part by mass.

In addition, if necessary, the encapsulant may be used as another additive such as a filler, a polymerization initiator, an antiaging agent, a wettability improver, a surfactant, a plasticizer, an ultraviolet absorber, and a preservative. An antibacterial agent or the like may be contained in an appropriate ratio.

<Image display device sealing sheet>
The above-mentioned sealing material can be distributed as it is and is an industrially applicable product, but from the viewpoint of handleability, it is preferably distributed as an image display device sealing sheet.

With reference to FIG. 1, the sealing sheet 1 as an embodiment of the image display device sealing sheet of the present invention will be described.

As shown in FIG. 1, the sealing sheet 1 includes a sealing layer 2 made of the above-mentioned sealing material, a base film 3, and a release film 4. The sealing sheet 1 is a component for manufacturing an image display device, and does not include a display element and a substrate on which the display element is mounted. Specifically, the sealing layer 2 and the base film 3 are separated from each other. It is a device that consists of a mold film 4, is distributed as a single component, and can be used industrially.

In order to prevent foreign matter from adhering to the sealing layer 2, it is preferable that the sealing layer 2 is protected by the base film 3 and the release film 4 when the sealing sheet 1 is stored. When the sealing sheet 1 is used, the base film 3 and the release film 4 are peeled off.

The sealing layer 2 is a dried product of the sealing material described above, and has a film shape (flat plate shape). Specifically, the sealing layer 2 has a predetermined thickness, extends in a predetermined direction orthogonal to the thickness direction, and has a flat front surface and a flat back surface.

In the sealing layer 2, the above-mentioned epoxy components (bisphenol skeleton-containing phenoxy resin, alicyclic skeleton-containing epoxy resin, bisphenol skeleton-containing epoxy resin) did not react, and the sealing layer 2 did not cure these epoxy components. Contains in the state.

The thickness of the sealing layer 2 is, for example, 1 μm or more, preferably 5 μm or more, for example, 100 μm or less, preferably 30 μm or less.

The base film 3 is detachably attached to the back surface of the sealing layer 2 in order to support and protect the sealing layer 2 until the sealing sheet 1 is used for forming the sealing member (described later). There is.
That is, the base film 3 is laminated on the back surface of the sealing layer 2 so as to cover the back surface of the sealing layer 2 at the time of shipping, transporting, and storing the sealing sheet 1, and immediately before the use of the sealing sheet 1. , A flexible film that can be peeled off from the back surface of the sealing layer 2 so as to be curved in a substantially U shape.

The base film 3 has a flat plate shape, specifically, has a predetermined thickness, extends in a predetermined direction orthogonal to the thickness direction, and has a flat front surface and a flat back surface. The sticking surface (surface) of the base film 3 is peeled off if necessary.

Examples of the material of the base film 3 include resin materials such as polyester (for example, polyethylene terephthalate (PET)) and polyolefin (for example, polyethylene, polypropylene, etc.), and polyethylene terephthalate is preferable.

Among the base films 3, a film having a moisture barrier property or a gas barrier property is preferable, and a film made of polyethylene terephthalate is more preferable. The thickness of the base film 3 is appropriately selected depending on the material of the film, but can be, for example, about 25 μm to 150 μm from the viewpoint of having the ability to follow the material to be sealed such as the display element.

The release film 4 is detachably attached to the surface of the sealing layer 2 in order to protect the sealing layer 2 until the sealing sheet 1 is used for forming the sealing member (described later). .. That is, the release film 4 is laminated on the surface of the sealing layer 2 so as to cover the surface of the sealing layer 2 at the time of shipping, transporting, and storing the sealing sheet 1, and immediately before the use of the sealing sheet 1. Is a flexible film that can be peeled off from the surface of the sealing layer 2 so as to be curved in a substantially U shape.

The release film 4 has a flat plate shape, specifically, has a predetermined thickness, extends in a predetermined direction orthogonal to the thickness direction, and has a flat front surface and a flat back surface. Further, the sticking surface (back surface) of the release film 4 is peeled off if necessary. Examples of the material of the release film 4 include the same resin material as the base film 3. The thickness of the release film 4 is appropriately selected depending on the material of the film, but can be, for example, about 25 μm to 150 μm from the viewpoint of having the ability to follow the material to be sealed such as the display element.

<Manufacturing method of image display device sealing sheet>
Next, a method for manufacturing the sealing sheet 1 will be described.

In order to manufacture the sealing sheet 1, for example, the above-mentioned sealing material is prepared, and the sealing material is applied to the surface of the base film 3 by a known method.

The encapsulant is prepared by mixing the above-mentioned resin component, curing agent and additive in the above-mentioned ratio. Further, in the production of the sealing sheet 1, the sealing material is preferably diluted with an organic solvent to prepare a varnish for the sealing material.

The organic solvent is not particularly limited as long as the resin component and the curing agent can be uniformly dispersed or dissolved. Organic solvents include, for example, aromatic hydrocarbons (eg, benzene, toluene, xylene, etc.), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ethers (eg, dibutyl ether, tetrahydrofuran, dioxane, ethylene). Glycol monoalkyl ethers, ethylene glycol dialkyl ethers, 1-methoxy-2-propanol, etc.), esters (eg, ethyl acetate, butyl acetate, etc.), nitrogen-containing compounds (eg, N-methylpyrrolidone, dimethylimidazolidinone, etc.) (Dimethylformaldehyde, etc.) and the like. The organic solvent can be used alone or in combination of two or more.

Among the organic solvents, ketones are preferable, and methyl ethyl ketone is more preferable. When the organic solvent contains ketones, the resin component (particularly, the bisphenol skeleton-containing phenoxy resin) can be uniformly dissolved.

The addition ratio of the organic solvent is, for example, 50 parts by mass or more, preferably 60 parts by mass or more, for example, 90 parts by mass or less, preferably 80 parts by mass or less with respect to 100 parts by mass of the resin component.

Each component can be mixed, for example, by dispersing with a ball mill, charging into a flask and stirring, or kneading with three rolls.

Moreover, as a method of coating a sealing material, for example, screen printing, a dispenser, a coating roll and the like can be mentioned.

The encapsulant is then dried and, if necessary, volatilized with an organic solvent to form a coating.

The heating temperature is a temperature at which the encapsulant dries without hardening, and is, for example, 20 ° C. or higher, preferably 90 ° C. or higher, for example 120 ° C. or lower, preferably less than 100 ° C. The heating time is, for example, 1 minute or more, preferably 2 minutes or more, for example, 30 minutes or less, preferably 15 minutes or less.

As a result, the coating film dries, and the sealing layer 2 formed from the sealing material is prepared. Next, the release film 4 is attached to the surface of the sealing layer 2.

As described above, the sealing sheet 1 is manufactured.

<Manufacturing of image display device>
Next, with reference to FIGS. 2, 3A to 3C, and FIG. 4, manufacturing of an organic EL display with a touch sensor (hereinafter, referred to as organic EL display 10) as an embodiment of a method for manufacturing an image display device. The method will be described.

In the present embodiment, the organic EL display with a touch sensor is mentioned as the image display device, but the image display device is not particularly limited. Examples of the image display device include a liquid crystal display (including a liquid crystal display with a touch sensor) and an organic EL display (including an organic EL display with a touch sensor). Among such image display devices, an organic EL display with a touch sensor is preferable, and an organic EL display with a capacitive touch sensor is more preferable. That is, the sealing material is preferably a sealing material for an organic EL display with a touch sensor, and the sealing sheet is preferably a sealing sheet for an organic EL display with a touch sensor.

The organic EL display 10 is manufactured by embedding the organic EL element 12 coated on the barrier layer 16 in the step of preparing the element mounting unit 11 (see FIG. 3A) and the sealing layer 2 of the sealing sheet 1. A step of attaching the cover glass or the barrier film 15 to the sealing layer 2 (see FIG. 3C), and a step of curing the sealing layer 2 to form the sealing member 14. (See FIG. 2).

In the method of manufacturing the organic EL display 10, first, as shown in FIG. 3A, the element mounting unit 11 is prepared. The element mounting unit 11 includes a substrate 13, an organic EL element 12 as an example of an optical element (display element), a barrier layer 16, and an electrode (not shown).

The substrate 13 supports the organic EL element 12. The substrate 13 preferably has flexibility.

The organic EL element 12 is a known organic EL element and is mounted on the substrate 13. Although not shown, the organic EL element 12 includes a cathode reflecting electrode, an organic EL layer, and an anode transparent electrode.

The barrier layer 16 covers the organic EL element 12 and prevents moisture in the atmosphere from coming into contact with the organic EL element 12. The barrier layer 16 includes a first inorganic barrier layer 17, a flattening layer 19, and a second inorganic barrier layer 18.

The first inorganic barrier layer 17 is arranged on the upper surface and the side surface of the organic EL element 12 so as to surround the organic EL element 12. Examples of the material of the first inorganic barrier layer 17 include metal oxides (for example, aluminum oxide, silicon oxide, copper oxide, etc.), metal nitrides (for example, aluminum nitride, silicon nitride, etc.) and the like. The material of the first inorganic barrier layer 17 can be used alone or in combination of two or more. Among the materials of the first inorganic barrier layer 17, metal nitride is preferable, and silicon nitride is more preferable.

The flattening layer 19 is arranged on the upper surface of the first inorganic barrier layer 17. Examples of the material of the flattening layer 19 include known resin materials.

The second inorganic barrier layer 18 is arranged on the upper surface and the side surface of the flattening layer 19 so as to surround the flattening layer 19. Examples of the material of the second inorganic barrier layer 18 include the same materials as those of the first inorganic barrier layer 17.

Electrodes (not shown) constitute a sensor for an organic EL display with a touch sensor. The electrodes (not shown) are located between the substrate 13 and the sealing member 14 (described later). For example, the electrodes (not shown) may be located in the substrate 13 or on the organic EL element 12.

Next, as shown by a virtual line in FIG. 1, the release film 4 is peeled off from the sealing sheet 1 and removed. Then, as shown in FIG. 3B, after the sealing sheet 1 is heated to the attachment temperature, the sealing layer 2 is placed on the substrate 13 so that the sealing layer 2 embeds the organic EL element 12 coated on the barrier layer 16. paste.

The sticking temperature is a temperature at which the sealing layer 2 softens without being cured, and is, for example, 40 ° C. or higher, preferably 60 ° C. or higher, for example 120 ° C. or lower, preferably 100 ° C. or lower.

Next, as shown by a virtual line in FIG. 3B, the base film 3 is peeled off from the sealing layer 2 and removed. Then, as shown in FIG. 3C, a cover glass or a barrier film 15 is attached to the upper surface of the sealing layer 2. Although not shown, the cover glass or the barrier film 15 includes a glass plate and electrodes provided on the lower surface of the glass plate and constituting a sensor of an organic EL display with a touch sensor.

Further, as shown in FIG. 4, after the sealing layer 2 is attached to the cover glass or the barrier film 15, the sealing layer 2 may be attached to the element mounting unit 11.

Next, as shown in FIG. 2, the sealing layer 2 is heated to a curing temperature to cure the sealing layer 2 to form the sealing member 14.

The curing temperature is higher than the drying temperature described above. The curing temperature is, for example, 70 ° C. or higher, preferably 80 ° C. or higher, for example, 150 ° C. or lower, preferably 120 ° C. or lower. The curing time is, for example, 10 minutes or more, preferably 30 minutes or more, for example, 2 hours or less, preferably 60 minutes or less.

As described above, the organic EL display 10 including the element mounting unit 11, the sealing member 14, and the cover glass or the barrier film 15 is manufactured. Such an organic EL display 10 is an organic EL display with a capacitance type touch sensor. Further, the organic EL display 10 has an in-cell structure in which the organic EL element 12 is arranged between two electrodes constituting the sensor, or one of the two electrodes constituting the sensor is arranged on the organic EL element 12. It has an on-cell structure.

The sealing member 14 is a cured product of the sealing layer 2 (sealing material) and seals the organic EL element 12 coated on the barrier layer 16.

The dielectric constant of the seal member 14 is, for example, 3.0 or more, preferably 3.2 or more, for example, less than 3.80, preferably 3.70 or less. The dielectric constant can be measured according to the method described in Examples described later.

When the dielectric constant of the sealing member 14 is at least the above lower limit, the degree of freedom in material selection can be improved. When the dielectric constant of the seal member 14 is not more than the above upper limit, it is possible to suppress the occurrence of malfunction in an organic EL display with a touch sensor or the like.

The haze value of the seal member 14 is, for example, 0.1 % or more, for example, less than 2.0%, preferably 1.5% or less, and more preferably less than 1.0%. The haze value can be measured according to the method described in Examples described later.

When the haze value of the seal member 14 is not more than the above upper limit, the visibility of the display (including the display with the touch sensor) can be improved.

Moisture permeability of the sealing member 14 is, for example, 20g ^/ m 2 · 24h or more, for example, 50g ^/ m 2 · 24h or less, preferably, 45 g ^/ m less than 2 · 24h, more preferably, 40g ^/ m 2 · 24h or less Is. The moisture permeability can be measured according to the method described in Examples described later.

When the moisture permeability of the seal member 14 is not more than the above upper limit, deterioration of the optical element sealed by the seal member 14 can be suppressed.

<Effect>
However, the sealing member of the liquid crystal display is provided in a frame shape so as to surround the periphery of the liquid crystal arranged between the base material and the glass plate, for example. On the other hand, as shown in FIG. 2, the seal member of the organic EL display is provided so that the organic EL element is embedded therein. Therefore, the sealing member of the organic EL display is more affected by the dielectric constant than the sealing member of the liquid crystal display, and it is desired to reduce the dielectric constant.

On the other hand, the sealing member of the organic EL display is not required to have a low dielectric constant as required for the sealing member of a normal semiconductor component.

The present inventors have added a non-styrene oligomer having an SP value of the above lower limit or more to the resin component of the encapsulant in addition to the styrene oligomer usually used as a tackifier or the like to form a bisphenol skeleton. The phenoxy resin contained, the epoxy resin containing an alicyclic skeleton, the styrene-based oligomer, and the non-styrene-based oligomer can be compatible with each other, and the dielectric constant of the sealing member formed from the encapsulant can be determined by the image display device. In particular, we have found that it can be adjusted to the range required for organic EL displays. Furthermore, it has been found that when a styrene-based oligomer and a non-styrene-based oligomer are added to the resin component, high transparency can be ensured while reducing the dielectric constant of the sealing member.

In the above-mentioned sealing material, since the resin component contains a styrene-based oligomer and a non-styrene-based oligomer, the dielectric constant of the sealing member can be reduced to the range required for an image display device (particularly an organic EL display), and an image can be obtained. It is possible to secure the high transparency required for a display device (particularly an organic EL display).

The non-styrene oligomer is preferably an aliphatic hydrocarbon resin and / or a terpene phenol resin. Therefore, it is possible to surely reduce the haze of the seal member while surely reducing the dielectric constant of the seal member.

Further, as shown in FIG. 1, the sealing sheet 1 has a sealing layer 2 made of a sealing material. Therefore, the handleability of the sealing material can be improved. Further, in the seal member, high transparency can be ensured while the dielectric constant can be reduced.

<Modification example>
In the modified example, the same members and processes as those in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, the sealing sheet 1 includes a sealing layer 2, a base film 3, and a release film 4, but the image display device sealing sheet of the present invention is not limited thereto. The image display device sealing sheet may not include the base film 3 and / or the release film 4 as long as it includes the sealing layer 2. That is, the image display device sealing sheet may be composed of only the sealing layer 2, or may include the sealing layer 2 and either the base film 3 or the release film 4.

As shown in FIG. 2, the organic EL display 10 includes, but is not limited to, the barrier layer 16. The organic EL display 10 does not have to include the barrier layer 16.

Further, the organic EL display 10 has an in-cell structure in which the organic EL element 12 is arranged between two electrodes constituting the sensor, or one of the two electrodes is arranged on the organic EL element 12. It has an on-cell structure, but is not limited to this.

For example, as shown in FIG. 5, the organic EL display 20 may have an out-cell structure in which two electrodes constituting the sensor are arranged above the seal member 14. The organic EL display 20 includes the above-mentioned element mounting unit 11, the above-mentioned sealing member 14, and the sensor unit 25.

The sensor unit 25 includes a glass substrate 23, an adhesive layer 21, and a cover glass 22. The glass substrate 23 is arranged on the upper surface of the sealing member 14. The glass substrate 23 includes electrodes constituting the sensor of the organic EL display with a touch sensor. The adhesive layer 21 is arranged between the glass substrate 23 and the cover glass 22, and adheres the glass substrate 23 and the cover glass 22. The cover glass 22 is arranged above the adhesive layer 21. The cover glass 22 includes electrodes constituting the sensor of the organic EL display with a touch sensor. In the organic EL display 20, the substrate 13 does not have an electrode.

Each of the above-described modifications also has the same effect as that of the above-described embodiment. The above embodiments and modifications can be combined as appropriate.

Examples are shown below, and the present invention will be described in more detail, but the present invention is not limited thereto. Specific numerical values such as the compounding ratio (content ratio), physical property values, and parameters used in the following description are the compounding ratios (content ratio) corresponding to those described in the above-mentioned "Form for carrying out the invention". ), Physical property values, parameters, etc., can be replaced with the upper limit (values defined as "less than or equal to" or "less than") or the lower limit (values defined as "greater than or equal to" or "excess"). it can. In addition, "part" and "%" are based on mass unless otherwise specified.

Examples 1-4
Bisphenol skeleton-containing phenoxy resin (trade name: JER-4275, manufactured by Mitsubishi Chemical Corporation, bisphenol A skeleton [ ^{constituent unit II in which two} R 2s are methyl groups in the above formula (1)] and bisphenol F skeleton [the above formula (1) ) containing two ^{R 2} is a hydrogen atom structural unit II] in a weight average molecular weight: about 60,000, epoxy equivalent:. 8,400~9, 2 00g / eq ) and a bisphenol skeleton-containing epoxy resin ( Product name: JER-4005P, manufactured by Mitsubishi Chemical Co., Ltd., weight average molecular weight: 6,200, epoxy equivalent: 1070 g / eq.) And ECH structure-containing epoxy compound (trade name: seroxide 2021P, 3,4-epoxycyclohexylmethyl) 3,4-Epoxy) cyclohexanecarboxylate, molecular weight: 252.3, epoxy equivalent: 128-145 g / eq.) And styrene-based oligomers (isopropenyltoluene (IPT) homopolymer, weight average molecular weight: 1200). , Ester-modified hydrocarbon resin (non-styrene oligomer, SP value 9.0, trade name: Quintone 1500, manufactured by Nippon Zeon, weight average molecular weight: 750) and thermal cation initiator (trade name: CXC-1612, King Industries). (Manufactured by the company) and methyl ethyl ketone (organic solvent) were mixed according to the formulations shown in Table 1 to prepare a varnish as a sealing material.

Example 5
A varnish as a sealing material was prepared in the same manner as in Example 4 except that the amount of the ECH structure-containing epoxy compound added was changed to 40 parts by mass and the bisphenol skeleton-containing epoxy resin was not added.

Example 6
Example 4 and Example 4 except that the ECH structure-containing epoxy compound was changed to a DCPD type epoxy resin (trade name: EP-4088S, manufactured by ADEKA, weight average molecular weight: 308.2, epoxy equivalent: 170 g / eq.). In the same manner, a varnish for the encapsulant was prepared.

Examples 7-9
The same as in Examples 1 to 3 except that the ester-modified hydrocarbon resin was changed to a terpene phenol resin having an SP value of 9.3 (non-styrene oligomer, trade name: YS Polystar K125, manufactured by Yasuhara Chemical Co., Ltd.). A varnish for the encapsulant was prepared.

Example 10
The varnish of the encapsulant was prepared in the same manner as in Example 9 except that the amount of the styrene-based oligomer added was changed to 10 parts by mass and the amount of the bisphenol skeleton-containing epoxy resin added was changed to 25 parts by mass. Prepared.

Comparative Example 1
Bisphenol skeleton-containing phenoxy resin (trade name: JER-4275, manufactured by Mitsubishi Chemical Co., Ltd.), bisphenol skeleton-containing epoxy resin (trade name: JER4005P, manufactured by Mitsubishi Chemical Co., Ltd.), and aromatic ring skeleton-containing epoxy resin (trade name: YL-). 983U, manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent: 169 g / eq., Weight average molecular weight: 326.2), thermal cation initiator (trade name: CXC-1612, manufactured by King Industries), and methyl ethyl ketone (organic solvent). Was mixed according to the formulation shown in Table 1 to prepare a varnish as a sealing material.

Comparative Example 2
A varnish as a sealing material was prepared in the same manner as in Comparative Example 1 except that the aromatic ring skeleton-containing epoxy resin was changed to an ECH structure-containing epoxy compound (trade name: seroxide 2021P).

Comparative Example 3
Except for the addition of 25 parts by mass of a styrene-based oligomer (a homopolymer of isopropenyl toluene (IPT), weight average molecular weight: 1200) and the addition of a bisphenol skeleton-containing epoxy resin to 25 parts by mass. , A varnish as a sealing material was prepared in the same manner as in Comparative Example 2.

Comparative Example 4
25 parts by mass of ester-modified hydrocarbon resin (non-styrene oligomer, SP value 9.0, trade name: Quintone 1500, manufactured by Nippon Zeon Co., Ltd.) was further added, and the amount of bisphenol skeleton-containing epoxy resin added was 25 parts by mass. A varnish as a sealing material was prepared in the same manner as in Comparative Example 2 except that it was changed to.

Comparative Example 5
Sealed in the same manner as in Comparative Example 4, except that the ester-modified hydrocarbon resin was changed to a terpene phenol resin having an SP value of 9.3 (non-styrene oligomer, trade name: YS Polystar K125, manufactured by Yasuhara Chemical Co., Ltd.). A wood varnish was prepared.

Comparative Example 6
15 parts by mass of styrene-based oligomer (isopropenyl toluene (IPT) homopolymer, weight average molecular weight: 1200) and ester-modified hydrocarbon resin (non-styrene-based oligomer, SP value 9.0, trade name: Quintone 1500, Nippon Zeon A varnish as a sealing material was prepared in the same manner as in Comparative Example 1 except that 10 parts by mass was further added.

Comparative Example 7
Varnish of sealing material in the same manner as in Example 4 except that the ester-modified hydrocarbon resin was changed to an aromatic-modified hydrocarbon resin (SP value 8.5, trade name: Quintone 1920, manufactured by Nippon Zeon Corporation). Was prepared.

Comparative Example 8
The varnish of the sealing material is the same as in Example 4 except that the ester-modified hydrocarbon resin is changed to a hydrogenated terpene resin (SP value 8.4, trade name: Clearon P-105, manufactured by Yasuhara Chemical Co., Ltd.). Was prepared.

Comparative Example 9
The sealing material is the same as in Example 4 except that the ester-modified hydrocarbon resin is changed to a hydrogenated aromatic terpene resin (SP value 8.5, trade name: Clearon M-105, manufactured by Yasuhara Chemical Co., Ltd.). Varnish was prepared.

Comparative Example 10
The sealing material is the same as in Example 4 except that the ester-modified hydrocarbon resin is changed to a rosin ester resin (SP value 8.5, trade name: Pine Crystal KE-100, manufactured by Arakawa Chemical Industry Co., Ltd.). Varnish was prepared.

Comparative Example 11
The encapsulant was prepared in the same manner as in Example 4 except that the ester-modified hydrocarbon resin was changed to a rosin resin (SP value 8.4, trade name: Pine Crystal KR-85, manufactured by Arakawa Chemical Industry Co., Ltd.). A varnish was prepared.

Comparative Example 12
A sealing material in the same manner as in Example 10 except that the terpene phenol resin having an SP value of 9.3 was changed to a terpene phenol resin having an SP value of 8.8 (trade name: YS Polystar T130, manufactured by Yasuhara Chemical Co., Ltd.). The varnish was prepared.

Comparative Example 13
A sealing material in the same manner as in Example 10 except that the terpene phenol resin having an SP value of 9.3 was changed to a terpene phenol resin having an SP value of 8.8 (trade name: YS Polystar T160, manufactured by Yasuhara Chemical Co., Ltd.). The varnish was prepared.

<Evaluation>
-Permittivity The varnish of the sealing material of each example and each comparative example was applied to a PET film by a coating machine (PET film released from a mold (trade name: Purex A53, manufactured by Teijin DuPont Film Co., Ltd., thickness: 38 μm). , Base film) and then dried in a nitrogen purge oven at 90 ° C. for 3 minutes to form a sealing layer having a thickness of 15 μm.

Next, a PET film (release-treated PET film (trade name: Purex A31, manufactured by Teijin DuPont Film Co., Ltd., thickness: 38 μm, release film)) was bonded to the sealing layer at 80 ° C. by a thermal laminator. ..

From the above, a sealing sheet including a base film, a sealing layer, and a release film was prepared. By repeating this, two sealing sheets were prepared for each example and comparative example. Then, in each of the two sealing sheets corresponding to the same Example or Comparative Example, after the release film is peeled from the sealing layer, the two sealing layers are bonded to each other in the thickness direction to obtain their thickness. Was 30 μm.

Next, the two sealing layers bonded to each other were peeled off from the base film on one side and cured at 100 ° C. for 1 hour, and then the base film on the other side was peeled off from the cured sealing layer for measurement. A sample was obtained. The dielectric constant of the obtained sample at 100 kHz was measured by an automatic equilibrium bridge method using an LCR meter HP4284A (manufactured by Agilent Technologies).

Then, the dielectric constant was evaluated according to the following criteria. The results are shown in Tables 1 and 2.
◯: Less than 3.80 ×: 3.80 or more.

-Haze value The sealing sheets of each Example and each Comparative Example were prepared in the same manner as in the above evaluation of the dielectric constant. Then, after the release film was peeled off from the sealing layer, the sealing layer was cured at 100 ° C. for 1 hour.
Then, the base film was peeled off from the cured sealing layer to obtain a sample for measurement. The haze value of the obtained sample was measured using a haze meter NDH2000 manufactured by Nippon Denshoku Kogyo Co., Ltd.

Then, the haze value was evaluated according to the following criteria. The results are shown in Tables 1 and 2.
◯: Less than 2.0% ×: 2.0% or more.

-Humidity Permeability In the same manner as in the evaluation of the dielectric constant described above, sealing sheets for each Example and each Comparative Example were prepared. Then, after the release film was peeled off from the sealing layer, the sealing layer was cured at 100 ° C. for 1 hour.
Then, the base film was peeled off from the cured sealing layer to obtain a sample for measurement. The moisture permeability (moisture permeability) of the obtained sample was measured at 60 ° C. and 90% RH conditions in accordance with JIS Z0208. Then, the film thickness of the sample used for the measurement was converted into a value when the thickness of the sample was 100 μm.

Then, the moisture permeability was evaluated according to the following criteria. The results are shown in Tables 1 and 2.
○: 45g ^/ m less than ^{2 · 24h △: 45g / m} 2 · 24h or more.

Although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an example and should not be construed in a limited manner. Modifications of the present invention that will be apparent to those skilled in the art are included in the claims below.

The image display device encapsulant and the image display device encapsulation sheet of the present invention are suitably used as encapsulants for various image display devices, specifically, encapsulants for liquid crystal displays, organic EL displays, and the like.

1 Sealing sheet 2 Sealing layer

Claims (7)

Contains a resin component and a curing agent,
The resin component is
A bisphenol skeleton-containing phenoxy resin having a weight average molecular weight of 10,000 or more and 100,000 or less,
An alicyclic skeleton-containing epoxy resin having a weight average molecular weight of 180 or more and 790 or less,
Styrene-based oligomers having a weight average molecular weight of 750 or more and 4000 or less,
It contains a non-styrene oligomer having a weight average molecular weight of 500 or more and less than 10,000 and a solubility parameter of 8.9 (cal / cm ³ ) ^1/2 or more.
In the resin component, the content ratio of the bisphenol skeleton-containing phenoxy resin is 5% by mass or more and 50% by mass or less.
In the resin component, the content ratio of the alicyclic skeleton-containing epoxy resin is 10% by mass or more and 50% by mass or less.
In the resin component, the content ratio of the styrene-based oligomer is 1% by mass or more and 40% by mass or less.
In the resin component, the content ratio of the non-styrene oligomer is 1% by mass or more and 30% by mass or less.
An image display device encapsulant, wherein the content ratio of the curing agent is 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the resin component. The non-styrene oligomer according to claim 1, wherein the non-styrene oligomer is an aliphatic hydrocarbon resin and / or a terpene phenol resin having a ^{solubility parameter of 8.9 (cal / cm 3} ) ^{1/2 or more.} Image display device Encapsulant. The image display device encapsulant according to claim 1 or 2 , wherein the content ratio of the non-styrene oligomer in the resin component is 10% by mass or more. The image display device encapsulant according to any one of claims 1 to 3, wherein the content ratio of the non-styrene oligomer to the styrene oligomer is 0.60 or more. The image display device encapsulant according to any one of claims 1 to 4, wherein the content ratio of the styrene-based oligomer in the resin component exceeds 10% by mass. The image display device encapsulant according to any one of claims 1 to 5, wherein the content ratio of the alicyclic skeleton-containing epoxy resin in the resin component is less than 40% by mass. An image display device sealing sheet comprising the image display device sealing material according to any one of claims 1 to 6.

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