WO2024204230A1 - Resin composition, liquid crystal sealing agent, and liquid crystal display panel using same - Google Patents

Abstract

The present invention addresses the problem of providing a resin composition which exhibits high adhesive strength to a substrate or an alignment film of a liquid crystal display panel despite exhibiting low moisture permeability when cured. A resin composition able to solve the foregoing problem contains: a thermosetting compound (A); a latent thermal curing agent (B) having a melting point of 110°C or less; a photocurable compound (C) having an ethylenically unsaturated double bond in the molecule; and a photopolymerization initiator (D). The thermosetting compound (A) includes a rubber-modified epoxy compound (a) having an epoxy group, an acrylonitrile-butadiene rubber structure and a bisphenol A type structure in a molecule.= The resin composition has a moisture permeation amount of less than 100 g/m² under prescribed conditions.

Description

Resin composition, liquid crystal sealant, and liquid crystal display panel using the same

The present invention relates to a resin composition, a liquid crystal sealant, and a liquid crystal display panel using the same.

In recent years, liquid crystal display panels have come into widespread use as devices for performing various displays. A typical liquid crystal display panel has a pair of substrates with electrodes on their surfaces, a pair of alignment films disposed between the substrates, a liquid crystal layer sandwiched between the pair of alignment films, and a frame-shaped sealant for sealing the liquid crystal layer. The sealant is generally disposed in the frame portion outside the effective display area of the liquid crystal display panel.

The above-mentioned sealant is required to have a high adhesive strength with the substrate in order to prevent leakage of the liquid crystal material from the liquid crystal layer. Therefore, the adhesive strength is increased by chemically bonding the functional groups (e.g., OH groups) on the substrate surface with the functional groups (e.g., epoxy groups) on the sealant surface (see, for example, Patent Document 1). On the other hand, the sealant is also required to have low moisture permeability so that it does not allow moisture from the outside to penetrate to the liquid crystal side.

JP 2005-018022 A

In recent years, there has been a demand to narrow the width of the frame of an LCD panel. When the width of the frame is narrowed, the distance from the edge of the alignment film to the edge of the LCD panel becomes very short, and the alignment film is placed in the frame (the area where the sealant is formed). However, most alignment films are hydrophobic. This makes it difficult to create a chemical bond between the sealant and the alignment film, and it has been difficult to obtain sufficient adhesive strength with conventional materials. In particular, reducing the moisture permeability of the sealant tends to reduce the adhesive strength between the substrate or alignment film and the sealant. In other words, it has been very difficult to form an encapsulant that combines high adhesive strength with the substrate or alignment film and low moisture permeability.

The present invention was made in consideration of the above problems, and aims to provide a resin composition and liquid crystal sealant that have low moisture permeability when cured but exhibit high adhesive strength to the substrate and alignment film of a liquid crystal display panel, as well as a liquid crystal display panel using the same.

The present invention provides a resin composition comprising a thermosetting compound (A), a latent thermosetting agent (B) having a melting point of 110°C or less, a photocurable compound (C) having an ethylenically unsaturated double bond in the molecule, and a photopolymerization initiator (D), wherein the thermosetting compound (A) comprises a rubber-modified epoxy compound (a) having an epoxy group, an acrylonitrile-butadiene rubber structure, and a bisphenol A type structure in one molecule, the resin composition being applied to a thickness of 100 μm, irradiated with light having a wavelength of 370 nm or more and 450 nm or less so that the integrated light amount is 300 mJ/ ^cm2 , and then heated at 120°C for 1 hour to harden the film, which has a moisture permeability at 60°C, 90% Rh, and 24 hours of less than 100 g/ ^m2 as measured in accordance with JIS Z0208:1976.

The present invention further provides a liquid crystal sealant containing the above resin composition.

The present invention further provides a liquid crystal display panel including a pair of substrates, an alignment film sandwiched between the pair of substrates, a liquid crystal layer sandwiched between the pair of alignment films, and a sealant for sealing the liquid crystal layer, the sealant being a cured product of the liquid crystal sealant.

The resin composition of the present invention has low moisture permeability when cured, yet exhibits high adhesive strength to the substrate and alignment film of a liquid crystal display panel.

In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower and upper limits.

1. Resin composition (liquid crystal sealant)
The resin composition of the present invention is a composition that can be cured by heat and light, and can be used, for example, as a liquid crystal sealant, etc. Hereinafter, the application of the resin composition to a liquid crystal sealant for forming a sealant for a liquid crystal display panel will be described as an example, but the use of the resin composition is not limited to a liquid crystal sealant.

The resin composition of the present invention contains at least a thermosetting compound (A) containing a specific rubber-modified epoxy compound (a), a latent thermosetting agent (B) having a melting point of 110°C or less, a photocurable compound (C) having an ethylenically unsaturated double bond in the molecule, and a photopolymerization initiator (D). The resin composition may further contain an inorganic filler (E), a silane coupling agent (F), core-shell type fine particles (G), etc., as necessary. In addition, as described below, the moisture permeability of the resin composition when cured under specified conditions is equal to or less than a certain value.

As mentioned above, there is a trade-off between the adhesive strength of the cured liquid crystal sealant (also referred to as the "sealant" in this specification) to the substrate or alignment film, and low moisture permeability, and it has been difficult to achieve both.

In contrast, the resin composition of the present invention has a high adhesive strength with the substrate, alignment film, etc. of a liquid crystal display panel, even though the moisture permeability after curing is below a certain value. The reason for this is unclear, but is thought to be as follows. In the resin composition of the present invention, the thermosetting compound (A) contains a rubber-modified epoxy compound (a) having an epoxy group, an acrylonitrile-butadiene rubber structure, and a bisphenol A type structure in one molecule. The rubber-modified epoxy compound (a) has a relatively flexible property due to its acrylonitrile-butadiene rubber structure. Therefore, the sealant obtained by curing the resin composition easily follows the deformation of the substrate, etc., and peeling is unlikely to occur at the interface between the sealant and the substrate or alignment film. Furthermore, when a force is applied to the liquid crystal display panel from the outside, the sealant can also relieve the stress. Therefore, the adhesive strength between the sealant and the substrate or alignment film is very high.

On the other hand, the bisphenol A skeleton of the rubber-modified epoxy compound (a) easily blocks moisture from entering the encapsulant from the outside. Therefore, the moisture permeability described below can be achieved. In other words, according to the resin composition of the present invention, an encapsulant having high adhesive strength to the substrate or alignment film of a liquid crystal display panel and low moisture permeability can be obtained.
Each component in the resin composition of the present invention will be described in detail below.

1-1. Thermosetting compound (A)
The thermosetting compound (A) may be any compound that is cured by heating, and at least a part or the whole of the compound is the rubber-modified epoxy compound (a).

The rubber-modified epoxy compound (a) may be a compound having at least one each of an epoxy group, an acrylonitrile-butadiene rubber structure, and a bisphenol A structure in one molecule, and there are no particular limitations on its structure. The rubber-modified epoxy compound (a) may have one epoxy group, but from the viewpoint of thermosetting properties, two or more are preferred.

Examples of the rubber-modified epoxy compound (a) include a compound in which an epoxy group is bonded to the end of a chain-like acrylonitrile-butadiene rubber structure via a bisphenol A type structure. The rubber-modified epoxy compound (a) can be a compound synthesized, for example, by the following method. First, an acrylonitrile-butadiene rubber of a desired molecular weight is prepared, and the end of the acrylonitrile-butadiene rubber is modified by a known method with a compound having a functional group capable of reacting with an epoxy group. Examples of groups capable of reacting with an epoxy group include a carboxy group, an amino group, a hydroxy group, etc., and among these, a carboxy group is preferred in terms of reactivity, etc. On the other hand, a multifunctional epoxy compound having a bisphenol A type structure is prepared. The multifunctional epoxy compound can be synthesized, for example, by reacting bisphenol A with epichlorohydrin. Then, a rubber-modified epoxy compound (a) having epoxy groups at both ends is obtained by reacting the functional group (e.g., a carboxy group) of the modified acrylonitrile-butadiene rubber described above with the epoxy group of the multifunctional epoxy compound. The structure of the rubber-modified epoxy compound can be identified, for example, by fractionation using gel permeation chromatography (GPC) followed by pyrolysis GC/MS or NMR. The rubber-modified epoxy compound may be a commercially available product. Examples of commercially available products include TSR-601 and TSR-060 (both manufactured by DIC Corporation).

The epoxy equivalent of the rubber-modified epoxy compound (a) is preferably 300 or more and 1000 or less, more preferably 400 or more and 600 or less. If the epoxy equivalent is 300 or more, the adhesive strength between the resulting sealant and the substrate or alignment film of the liquid crystal display panel is likely to be further increased. On the other hand, if the epoxy equivalent of the rubber-modified epoxy compound (a) is 1000 or less, the resulting sealant does not become excessively flexible, and it becomes easier to stably seal the liquid crystal. In addition, it prevents the moisture permeability from being significantly deteriorated. The epoxy equivalent is the value obtained by dividing the molecular weight of the rubber-modified epoxy compound (a) by the number of epoxy groups contained in the molecule, and the average molecular weight can be determined by gel permeation chromatography (GPC).

The molecular weight of the rubber-modified epoxy compound (a) is preferably 2000 or less, and more preferably 600 to 1200. When the average molecular weight of the rubber-modified epoxy compound (a) is 2000 or less, the applicability of the resin composition is further improved, and it becomes easier to form an encapsulant with a desired width. In addition, from the viewpoint of making it easier to adjust the low moisture permeability described below to a more desired range, it is preferable that the molecular weight of the rubber-modified epoxy compound (a) is 2000 or less.

The amount of the rubber-modified epoxy compound (a) is preferably 10 parts by mass or more and 25 parts by mass or less, and more preferably 14 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the total amount of the thermosetting compound (A) and the photocurable compound (C) described below. When the amount of the rubber-modified epoxy compound (a) is 10 parts by mass or more relative to the total amount of the thermosetting compound (A) and the photocurable compound (C), the moisture permeability of the encapsulant is likely to be further reduced. On the other hand, when the amount of the rubber-modified epoxy compound (a) is 25 parts by mass or less, the amount of the photocurable compound (C) becomes relatively large, and the photocurability of the resin composition is likely to be further improved.

Thermosetting compound (A) may contain other thermosetting compounds in addition to the rubber-modified epoxy compound (a). Examples of other thermosetting compounds include epoxy-based compounds having an epoxy group. However, in this specification, even if a compound has an epoxy group, a compound having an ethylenically unsaturated double bond is classified as a photocurable compound (C) described below, and is not included in the thermosetting compound (A). The thermosetting compound (A) may contain only one type of epoxy-based compound, or may contain two or more types.

The epoxy compound may contain only one epoxy group in the molecule, or may contain two or more epoxy groups. Examples of epoxy compounds include aromatic epoxy compounds, aliphatic epoxy compounds, and alicyclic epoxy compounds, but aromatic epoxy compounds are preferred from the viewpoint of making it easier to keep the moisture permeability of the resulting sealing material within the range described below.

Examples of aromatic epoxy compounds include aromatic polyfunctional glycidyl ether compounds obtained by reacting epichlorohydrin with aromatic diols such as bisphenol A, bisphenol S, bisphenol F, and bisphenol AD, or diols obtained by modifying these aromatic diols with ethylene glycol, propylene glycol, alkylene glycol, or the like; novolac-type polyfunctional glycidyl ether compounds obtained by reacting epichlorohydrin with polyphenols such as novolac resins derived from phenol or cresol and formaldehyde, polyalkenylphenols, and their copolymers; and glycidyl ether compounds of xylylene phenol resins.

Among these, cresol novolac type epoxy compounds, phenol novolac type epoxy compounds, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, triphenol methane type epoxy compounds, triphenol ethane type epoxy compounds, trisphenol type epoxy compounds, dicyclopentadiene type epoxy compounds, diphenyl ether type epoxy compounds, and biphenyl type epoxy compounds are preferred.

The epoxy compound may be liquid or solid. From the viewpoint of reducing the moisture permeability of the resulting sealing material, a solid epoxy compound is preferred. The softening point of a solid epoxy compound is preferably 40°C or higher and 150°C or lower. The softening point can be measured by the ring and ball method specified in JIS K7234.

The weight average molecular weight of the epoxy compound is preferably 300 to 10,000, and more preferably 500 to 5,000. The weight average molecular weight of the epoxy compound is measured in terms of polystyrene by gel permeation chromatography (GPC).

Here, the total amount of the thermosetting compound (A) in the resin composition (the total amount of the rubber-modified epoxy compound (a) and other thermosetting compounds) is preferably 30% by mass or more and 70% by mass or less, and more preferably 40% by mass or more and 60% by mass or less, relative to the total amount of the resin composition. If the amount of the thermosetting compound (A) is 40% by mass or more, the moisture permeability of the encapsulant tends to be lower. On the other hand, if the amount of the thermosetting compound (A) is 60% by mass or less, the amount of the photocurable compound (C) described below becomes relatively large, and the photocurability of the resin composition tends to be good.

1-2. Latent heat curing agent (B)
The latent heat curing agent (B) is a compound that does not cure the heat curable compound (A) under normal storage conditions (room temperature, visible light, etc.), but cures these compounds when heat is applied, and is not particularly limited as long as the melting point is 110 ° C or less. The melting point of the latent heat curing agent (B) is more preferably 70 ° C or more and 100 ° C or less. When curing the resin composition, in order to make the latent heat curing agent (B) act, it is necessary to raise the temperature to the vicinity of its melting point. However, if the temperature of the resin composition is raised to a high temperature, the uncured photocurable compound (C) is likely to dissolve into the liquid crystal. In contrast, if the melting point of the latent heat curing agent (B) is 110 ° C or less, such dissolution is unlikely to occur. The resin composition may contain only one type of latent heat curing agent (B), or may contain two or more types.

The latent heat curing agent (B) is appropriately selected according to the above-mentioned heat curing compound (A), but a curing agent that can open the epoxy group of the above-mentioned rubber-modified epoxy compound (a) to cure it (hereinafter also referred to as "epoxy curing agent") is preferable.

Examples of epoxy curing agents (latent heat curing agents (B)) include dihydrazide-based heat latent curing agents, amine adduct-based heat latent curing agents, polyamine-based heat latent curing agents, dicyandiamide-based heat latent curing agents, imidazole-based heat latent curing agents, etc. The resin composition may contain only one of these, or two or more of them.

Examples of dihydrazide-based thermal latent curing agents with a melting point of 110°C or less include 1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin, 7,11-octadecadiene-1,18-dicarbohydrazide, dodecanedioic acid dihydrazide, and sebacic acid dihydrazide.

Amine adduct heat-latent curing agents are heat-latent curing agents consisting of an addition compound obtained by reacting an amine compound with catalytic activity with any compound. Commercially available examples of amine adduct heat-latent curing agents include Amicure PN-40, Amicure PN-23, Amicure PN-31, Amicure PN-H, and Amicure MY-24 (all manufactured by Ajinomoto Fine-Techno Co., Ltd.).

Polyamine-based thermal latent curing agents are thermal latent curing agents with a polymer structure obtained by reacting amines with epoxy resins, and examples of commercially available products include ADEKA HARDENER EH4339S, ADEKA HARDENER EH4357S, and ADEKA HARDENER EH5030S (all manufactured by ADEKA Corporation).

Examples of dicyandiamide-based thermal latent curing agents include dicyandiamide, etc.

Examples of imidazole-based thermal latent hardeners include ADEKA Hardener EH-4344S and EH-5011S (both manufactured by ADEKA Corporation), 2,4-diamino-6-[2'-ethylimidazolyl-(1')]-ethyltriazine, and 2-phenylimidazole.

Among the above, imidazole-based heat-latent curing agents, amine adduct-based heat-latent curing agents, and polyamine-based heat-latent curing agents are preferred in terms of reactivity, etc.

The amount of latent heat curing agent (B) is preferably 2% by mass or more and 15% by mass or less, more preferably 3% by mass or more and 14% by mass or less, and even more preferably 3% by mass or more and 12% by mass or less, based on the total amount of the resin composition.

1-3. Photocurable compound (C)
The photocurable compound (C) is not particularly limited as long as it has at least one ethylenically unsaturated double bond in the molecule and is polymerizable by light. Examples of the photocurable compound include (meth)- ) (meth)acrylic compounds that contain an acryloyl group but no epoxy group, and (meth)acrylic-modified epoxy compounds that have a (meth)acryloyl group and an epoxy group in the molecule.

The (meth)acrylic compound may be any compound that contains one or more (meth)acryloyl groups in one molecule and does not contain an epoxy group, and the number of (meth)acryloyl groups may be one or more. Examples of monofunctional (meth)acrylic compounds that contain one (meth)acryloyl group in one molecule include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, isobornyl (meth)acrylic, dicyclopentanyl (meth)acrylic, and (meth)acrylic acid 2-hydroxyethyl ester.

Examples of polyfunctional (meth)acrylic compounds having two or more (meth)acryloyl groups in one molecule include di(meth)acrylates derived from polyethylene glycol, propylene glycol, polypropylene glycol, etc.; di(meth)acrylates derived from tris(2-hydroxyethyl)isocyanurate: di(meth)acrylates derived from diols obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol; di(meth)acrylates derived from diols obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A or bisphenol F; di(meth)acrylates derived from diols obtained by adding ethylene oxide to 1 mole of trimethylolpropane (bisphenol A or F type epoxy(meth)acrylate); di- or tri(meth)acrylates derived from polyols obtained by adding 2 or 3 moles of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane; di(meth)acrylates derived from diols obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A; tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate; trimethylolpropane; pentaerythritol tri(meth)acrylate or its oligomer; dipentaerythritol poly(meth)acrylate; tris(acryloxyethyl)isocyanurate; caprolactone modified tris(acryloxyethyl)isocyanurate; caprolactone modified tris(methacryloxyethyl)isocyanurate; alkyl modified dipentaerythritol poly(meth)acrylate; caprolactone modified dipentaerythritol poly(meth)acrylate; hydroxypivalic acid neopen These include di(meth)acrylates obtained by adding 2 moles of succinic acid or phthalic acid and hydroxypropyl (meth)acrylate to 1 mole of bisphenol A or bisphenol F; and oligo(meth)acrylates of neopentyl glycol, trimethylolpropane, and pentaerythritol. Among these, di(meth)acrylates derived from diols obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A or bisphenol F (bisphenol A or F type epoxy (meth)acrylate) are preferred.

However, as the amount of monofunctional (meth)acrylic compounds increases, the moisture permeability of the resulting cured product tends to increase. Therefore, the total amount of monofunctional (meth)acrylic compounds relative to the total amount of photocurable compounds (C) is preferably 20 mass% or less, and more preferably 10 mass% or less.

The weight average molecular weight of the (meth)acrylic compound as measured by gel permeation chromatography (GPC) is preferably 200 to 10,000, and more preferably 200 to 5,000.

On the other hand, the (meth)acrylic modified epoxy compound may be any compound having one or more epoxy groups and one or more (meth)acryloyl groups in the molecule, and the number of epoxy groups and (meth)acryloyl groups is not particularly limited. For example, it may have one epoxy group and one (meth)acryloyl group, or it may have two or more of either one or both. The (meth)acrylic modified epoxy compound has good compatibility with the above-mentioned thermosetting compound (A). Therefore, when the photocurable compound (C) contains a (meth)acrylic modified epoxy compound, the compatibility between them becomes very good.

(Meth)acrylic modified epoxy compounds are compounds in which some of the epoxy groups of an epoxy compound having, for example, difunctional or higher functionality are modified with (meth)acrylic acid. The epoxy compound used for the modification only needs to have two or more epoxy groups in the molecule, and from the viewpoint of preventing excessive decrease in adhesive strength of the sealing material due to excessive increase in crosslink density, a difunctional epoxy compound is preferred. Examples of difunctional epoxy compounds include bisphenol type epoxy compounds (bisphenol A type, bisphenol F type, 2,2'-diallyl bisphenol A type, bisphenol AD type, hydrogenated bisphenol type, etc.), biphenyl type epoxy compounds, and naphthalene type epoxy compounds. Among them, bisphenol type epoxy compounds of bisphenol A type and bisphenol F type are preferred from the viewpoint of improving the coatability of the resin composition (liquid crystal sealant). (Meth)acrylic modified epoxy compounds derived from bisphenol type epoxy compounds have advantages such as excellent coatability compared to (meth)acrylic modified epoxy compounds derived from biphenyl ether type epoxy compounds.

The weight average molecular weight of the (meth)acrylic modified epoxy compound measured by gel permeation chromatography (GPC) is preferably 300 to 1000.

When the photocurable compound (C) is either a (meth)acrylic compound or a (meth)acrylic-modified epoxy compound, the (meth)acrylic equivalent is preferably 2500 or less, more preferably 1000 or less. If the (meth)acrylic equivalent is 1000 or less, the photocurability is good and the moisture permeability of the resulting sealant is likely to be low. The (meth)acrylic equivalent is the value obtained by dividing the molecular weight of the (meth)acrylic compound or meth)acrylic-modified epoxy compound by the number of (meth)acrylic groups contained in the molecule, and the molecular weight is measured in polystyrene equivalent terms by gel permeation chromatography (GPC).

The total amount of the photocurable compounds (C) is preferably 30% by mass or more and 70% by mass or less, and more preferably 40% by mass or more and 60% by mass or less, relative to the total amount of the resin composition. When the total amount of the photocurable compounds (C) is within this range, the photocurability of the resin composition is improved, and the tendency to contaminate liquid crystals is likely to be reduced.

1-4. Photopolymerization initiator (D)
The photopolymerization initiator (D) is not particularly limited as long as it is a compound capable of polymerizing the photocurable compound (C) by irradiation with light. The photopolymerization initiator (D) may be a self-cleavage type photopolymerization initiator or a hydrogen abstraction type photopolymerization initiator. The resin composition may contain only one type of photopolymerization initiator (D), or may contain two or more types.

Examples of self-cleaving photopolymerization initiators include alkylphenone compounds (benzyl dimethyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethan-1-one (BASF, IRGACURE 651); α-amino alkylphenone compounds such as 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one (BASF, IRGACURE 907); 1-hydroxy-cyclohexyl-phenyl-ketone (BASF, IRGACURE 18); 4) and other α-hydroxyalkylphenone compounds; acylphosphine oxide compounds such as 2,4,6-trimethylbenzoin diphenylphosphine oxide; titanocene compounds such as bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium; diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-(4-isopropyl acetophenone-based compounds such as 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone; phenylglyoxylate-based compounds such as methylphenylglyoxyester; These include benzoin ether compounds such as benzoin methyl ether, benzoin isopropyl ether, and oxime ester compounds such as 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzoyloxime)] (manufactured by BASF, IRGACURE OXE01) and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (manufactured by BASF, IRGACURE OXE02).

Examples of hydrogen abstraction type photopolymerization initiators include benzophenone compounds such as benzophenone, o-benzoyl methylbenzoate-4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone (Tokyo Chemical Industry Co., Ltd.), 1-chloro-4-propoxythioxanthone, 1-chloro-4-ethoxythioxanthone (Lambson Limited, Speedcure CPTX), and 2-isopropylxanthone (Lambson Limited, Speedcure CPTX). These include thioxanthone compounds such as thioxanthone, 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone (manufactured by Lambson Limited, Speedcure DETX), and 2,4-dichlorothioxanthone; anthraquinone compounds such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone, 2-hydroxyanthraquinone (manufactured by Tokyo Chemical Industry Co., Ltd., 2-hydroxyanthraquinone), 2,6-dihydroxyanthraquinone (manufactured by Tokyo Chemical Industry Co., Ltd., anthraflavic acid), and 2-hydroxymethylanthraquinone (manufactured by Junsei Chemical Co., Ltd., 2-(hydroxymethyl)anthraquinone); and benzyl compounds.

The absorption wavelength of the photopolymerization initiator (D) is not particularly limited, and for example, a photopolymerization initiator (D) that absorbs light with a wavelength of 360 nm or more is preferred. Among these, it is more preferable that the photopolymerization initiator (D) absorbs light in the visible light region, and a photopolymerization initiator (D) that absorbs light with a wavelength of 360 to 430 nm is particularly preferred. When the photopolymerization initiator (D) has an absorption wavelength in this range, it becomes possible to cure the resin composition by irradiating it with visible light, and the effect on liquid crystal materials, etc. can be greatly reduced. In this specification, the "visible light region" refers to a wavelength range of 360 nm to 780 nm.

Examples of photopolymerization initiators (D) that absorb light with a wavelength of 360 nm or more include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, titanocene-based photopolymerization initiators, oxime ester-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and anthraquinone-based photopolymerization initiators, of which oxime ester-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and anthraquinone-based photopolymerization initiators are preferred.

The structure of the photopolymerization initiator (D) can be determined by combining high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS) with NMR or IR measurements.

The molecular weight of the photopolymerization initiator (D) is preferably, for example, 200 or more and 5000 or less. If the molecular weight is 200 or more, when the resin composition is used as a liquid crystal sealant, the photopolymerization initiator (D) is less likely to dissolve into the liquid crystal material. On the other hand, if the molecular weight is 5000 or less, the compatibility with the photocurable compound (C) is increased, and the photocurability of the resin composition is likely to be good. The molecular weight of the photopolymerization initiator (D) is more preferably 230 or more and 3000 or less, and even more preferably 230 or more and 1500 or less.

The molecular weight of the photopolymerization initiator (D) can be determined as the "relative molecular mass" of the molecular structure of the main peak detected when analyzed by high performance liquid chromatography (HPLC).

Specifically, a sample solution is prepared by dissolving the photopolymerization initiator (D) in THF (tetrahydrofuran), and high performance liquid chromatography (HPLC) measurement is performed. The area percentage of the detected peak (ratio to the total area of each peak) is then calculated to confirm the presence or absence of a main peak. The main peak is the peak with the greatest intensity (the peak with the highest height) among all peaks detected at a detection wavelength characteristic of each compound (for example, 400 nm for thioxanthone compounds). The relative molecular mass corresponding to the peak apex of the detected main peak can be measured by liquid chromatography mass spectrometry (LC/MS).

The amount of photopolymerization initiator (D) is preferably 0.01 to 10 mass% relative to the total amount of photocurable compound (C), more preferably 0.1 to 5 mass%, even more preferably 0.1 to 3 mass%, and particularly preferably 0.1 to 2.5 mass%. When the amount of photopolymerization initiator (D) is 0.01 mass% or more relative to the total amount of photocurable compound (C), the photocurability of the resin composition tends to be good. On the other hand, when the content of photopolymerization initiator (D) is 10 mass% or less, the photopolymerization initiator (D) is less likely to dissolve into the liquid crystal when the resin composition is used as a liquid crystal sealant.

1-5. Inorganic filler (E)
The resin composition may further contain an inorganic filler (E). When the resin composition contains the inorganic filler (E), the hardness of the resin composition tends to increase and the moisture permeability tends to further decrease. The resin composition may contain only one type of inorganic filler (E), or may contain two or more types.

Examples of inorganic fillers (E) include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, titanium nitride, alumina other than the above, zinc oxide, silicon oxide (silica), potassium titanate, kaolin, talc, glass beads, sericite activated clay, bentonite, aluminum nitride, and silicon nitride. Among these, silica, alumina, and talc are preferred from the viewpoints of availability and stability.

The shape of the inorganic filler (E) may be regular, such as spherical, plate-like, or needle-like, or may be irregular. When the inorganic filler is spherical, the average primary particle size of the inorganic filler is preferably 1.5 μm or less. The specific surface area of the inorganic filler is preferably 0.5 m ² /g or more and 20 m ² /g or less. The average primary particle size of the inorganic filler can be measured by the laser diffraction method described in JIS Z8825 (2013). The specific surface area of the filler is measured by the BET method described in JIS Z8830 (2013).

The amount of inorganic filler (E) in the resin composition is preferably 10 parts by mass or more, and more preferably 13 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the total amount of the thermosetting compound (A), the latent thermosetting agent (B), the photocurable compound (C), and the photopolymerization initiator (D). Furthermore, the amount of inorganic filler (E) is preferably 10 parts by mass or more and 40 parts by mass or less, and more preferably 14 parts by mass or more and 30 parts by mass or less, relative to the total amount of the resin composition. If the content of inorganic filler (E) is high, the moisture permeability of the resulting sealing material tends to be low. However, if the content is too high, the coatability of the resin composition decreases, so the above range is preferable.

1-6. Silane coupling agent (F)
The resin composition may further contain a silane coupling agent (F). When the resin composition contains a silane coupling agent (F), the adhesive strength between the obtained sealing material and the substrate or the alignment film tends to be further increased.

Examples of silane coupling agents include vinyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, etc.

The amount of the silane coupling agent (F) is preferably 1% by mass or more and 20% by mass or less based on the total amount of the resin composition. If the content of the silane coupling agent is within this range, as described above, the adhesive strength between the obtained sealing material and the substrate or alignment film tends to be further increased.

1-7. Core-shell type fine particles (G)
The resin composition may further contain core-shell type fine particles (G). Core-shell type fine particles are fine particles having a core having desired physical properties and a shell portion covering the core. The shell portion can increase compatibility with other components or cause partial reaction with other components. In addition, when the resin composition contains the core-shell type fine particles (G), the resin composition absorbs and expands surrounding materials when heated, reducing liquid crystal contamination. The resin composition may contain only one type of core-shell type fine particles (G), or may contain two or more types.

Examples of core-shell type microparticles (G) include organic microparticles having an elastic core containing conjugated diene rubber, silicone rubber, etc., and a shell made of a polymer such as (meth)acrylate, vinyl monomer, or epoxy monomer.

Another example of the core-shell type microparticles (G) includes microparticles having a core made of an inorganic particle and a shell portion made of a polymer layer covering the core, and having a functional group containing a carbon-carbon double bond on the surface. Examples of the functional group containing a carbon-carbon double bond that the core-shell type microparticles have include vinyl groups, allyl groups, acrylic groups, and methacrylic groups. Examples of the core in the core-shell type microparticles include particles similar to those of the inorganic filler (E) above. Among these, silica particles are preferred from the viewpoint of excellent thermal stability.

The average primary particle diameter of the core-shell type microparticles (G) is preferably 0.1 to 1.0 μm, more preferably 0.2 to 0.8 μm, and even more preferably 0.3 to 0.5 μm. The average primary particle diameter of the core-shell type microparticles (G) can be determined by a microscopic method. Specifically, it can be measured by image analysis using an electron microscope. More specifically, image analysis is performed on the liquid crystal sealant, 50 organic fillers with a particle diameter of 1 μm or less are selected, and the average value of the particle diameters measured is taken as the average particle diameter.

The amount of the core-shell type microparticles (G) is preferably 1% by mass or more and 12% by mass or less, and more preferably 5% by mass or more and 10% by mass or less, based on the total amount of the resin composition. When the content of the core-shell type microparticles (G) is within this range, it becomes easier to adjust the physical properties of the resulting sealing material to the desired range.

1-8. Other Components The resin composition of the present invention may further contain various additives as necessary. Examples of the various additives include a thermal radical polymerization initiator, an ion trapping agent, an ion exchange agent, a leveling agent, a pigment, a dye, a sensitizer, a plasticizer, and an antifoaming agent.

Furthermore, the resin composition may contain spacers for adjusting the gap of the liquid crystal display panel.

The total amount of the other components is preferably 1% by mass or more and 50% by mass or less, and more preferably 1% by mass or more and 25% by mass or less, relative to the total amount of the resin composition. When the total amount of the other components is 50% by mass or less of the resin composition, the viscosity of the resin composition is unlikely to increase excessively, and the coating stability of the resin composition is unlikely to be impaired.

1-9. Physical properties of the resin composition The resin composition of the present invention is applied to a thickness of 100 μm, irradiated with light having a wavelength of 370 nm or more and 450 nm or less so that the accumulated light amount is 3000 mJ/cm ² , and then heated at 120 ° C. for 1 hour to harden the film, and the moisture permeability at 60 ° C., 90% Rh, and 24 hours measured in accordance with JIS Z0208:1976 is less than 100 g/m ^2. The moisture permeability is preferably 90 g/m ² or less, and more preferably 85 g/m ² or less. If the moisture permeability under the above conditions is less than 100 g/m ² , the liquid crystal display panel can be used stably for a long period of time. In the measurement of the moisture permeability, an aluminum cup is made from the film hardened under the above curing conditions, and this is placed in a high-temperature, high-humidity tank at 60 ° C., 90% Rh. Then, the moisture permeability is calculated from the mass before and after placing in the high-temperature, high-humidity tank using the following formula.
Moisture permeability (g/ ^m2 ·100μm·24h) = [weight of aluminum cup after being left for 24 hours (g) - weight of aluminum cup before being left for 24 hours (g)] / film area ( ^m2 )

On the other hand, the viscosity of the resin composition at 25°C and 2.5 rpm using an E-type viscometer is preferably 200 to 450 Pa·s, and more preferably 250 to 400 Pa·s. If the viscosity is within the above range, the resin composition can be easily applied using a dispenser, etc.

Here, the resin composition can be used as a liquid crystal sealant as described above. The liquid crystal sealant may contain only the resin composition, or may be a mixture of the resin composition and other components as necessary.

This liquid crystal sealant is primarily useful as a sealant for liquid crystal display panels, but is also useful as a sealant for display elements other than liquid crystal display panels, such as organic EL elements and LED elements.

2. Liquid crystal display panel and its manufacturing method (Structure of liquid crystal display panel)
The liquid crystal display panel of the present invention includes a pair of substrates, a pair of alignment films disposed between the pair of substrates, a liquid crystal layer sandwiched between the pair of alignment films, and a sealant for sealing the liquid crystal layer. The sealant is a cured product of the above-mentioned resin composition (liquid crystal sealant).

Both of the pair of substrates are transparent. The material of the transparent substrate may be an inorganic material such as glass, or may be a plastic such as polycarbonate, polyethylene terephthalate, polyethersulfone, and PMMA. A matrix-shaped TFT, a color filter, a black matrix, etc. may be arranged on the surface of each substrate.

Also, an alignment film is arranged on the inside (liquid crystal layer side) of each substrate. The type of alignment film is not particularly limited, and includes films made of known organic alignment agents or inorganic alignment agents. The alignment film may be arranged so as to cover substantially the entire one surface of each substrate, that is, to extend from one end of the substrate to the other end. The alignment film may also be arranged so as to cover only a partial area of the substrate, or may be arranged with a gap between the end of the alignment film and the end of the substrate.

Furthermore, the liquid crystal layer may be a layer made of a liquid crystal material sandwiched between the alignment films, and the type of the liquid crystal material is not particularly limited.
The sealant is a frame-shaped structure disposed so as to surround the liquid crystal layer. In the liquid crystal display panel of the present invention, the sealant may be disposed so as to be sandwiched between the alignment films.

As mentioned above, it is difficult to sufficiently increase the adhesive strength between a normal sealant and an alignment film, but by using the above-mentioned resin composition, it is possible to increase the adhesive strength between the alignment film and the sealant even when the sealant is fabricated on an alignment film. Therefore, the above-mentioned resin composition (liquid crystal sealant) is very useful in the case of narrowing the frame of a liquid crystal display panel.

(Method of manufacturing liquid crystal display panel)
The liquid crystal display panel is manufactured by using the liquid crystal sealant of the present invention. Generally, there are a liquid crystal dropping method and a liquid crystal injection method for manufacturing a liquid crystal display panel, but the liquid crystal display panel of the present invention is preferably manufactured by the liquid crystal dropping method.

The manufacturing method for liquid crystal display panels using the liquid crystal dropping method is as follows:
1) preparing two substrates with an alignment film having a substrate and an alignment film;
2) applying the above-mentioned liquid crystal sealant (resin composition) onto the surface of one of the alignment film-coated substrates on which the alignment film is formed, to form a frame-shaped pattern;
3) dropping liquid crystal onto the inside of the frame-shaped pattern of one of the alignment film-attached substrates or onto the other alignment film-attached substrate while the frame-shaped pattern is in an uncured state;
4) superposing one substrate with an alignment film and the other substrate with an alignment film via a frame-shaped pattern;
5) curing the frame-shaped pattern.

In step 2), the area to which the liquid crystal sealant (resin composition) is applied is appropriately selected according to the desired structure of the liquid crystal display panel. For example, when the sealant is disposed on an alignment film, the liquid crystal sealant (resin composition) is applied onto the alignment film. There are no particular limitations on the method of applying the liquid crystal sealant (resin composition) as long as the liquid crystal sealant (resin composition) can be applied in the desired width, but it can be applied, for example, by a dispenser or the like.

On the other hand, in step 3), the frame-shaped pattern being in an uncured state means that the curing reaction of the liquid crystal sealant has not progressed to the gel point. For this reason, in step 3), the frame-shaped pattern may be semi-cured by light irradiation or heating in order to suppress dissolution of the liquid crystal sealant into the liquid crystal. In addition, when liquid crystal is dropped onto the other substrate with an alignment film in step 3), the liquid crystal is dropped so that it fits inside the frame-shaped pattern when the two substrates with alignment films are superimposed in step 4).

In step 5), it is preferable to perform curing by heating after curing by light irradiation. By performing curing by light irradiation first, the liquid crystal sealant can be cured in a short time, which makes it possible to suppress dissolution into the liquid crystal. Furthermore, by combining curing by light irradiation with curing by heating, damage to the liquid crystal layer caused by light can be reduced compared to curing by light irradiation alone.

The light to be irradiated is selected appropriately depending on the type of photopolymerization initiator (D) in the liquid crystal sealant (resin composition) described above, but light in the visible light region is preferred, for example light with a wavelength of 370 to 450 nm. Light with the above wavelengths causes relatively little damage to the liquid crystal material and driving electrodes. For the light irradiation, known light sources that emit ultraviolet light or visible light can be used. When irradiating visible light, high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, xenon lamps, fluorescent lamps, etc. can be used.

The light irradiation energy may be sufficient as long as it is capable of curing the photocurable compound (C). The photocuring time depends on the composition of the liquid crystal sealant, but is, for example, about 10 minutes.

The heat curing temperature depends on the composition of the liquid crystal sealant, but is, for example, 120°C, and the heat curing time is about 2 hours.

The present invention will be specifically explained below with reference to examples, but the scope of the present invention is not limited to the description of the examples.

1. Preparation of materials (thermosetting compound (A))
Carboxy-modified acrylonitrile-butadiene rubber modified bisphenol A type epoxy resin (TSR-601, manufactured by DIC Corporation, epoxy equivalent: 450-500, molecular weight: 948)
Bisphenol A type PO modified epoxy resin (EP-4003S, manufactured by ADEKA Corporation, epoxy equivalent: 470, molecular weight: 940)
Epoxidized polybutadiene (PB4700, manufactured by Daicel Corporation, epoxy equivalent: 165, number average molecular weight: 3000)

(Latent Heat Curing Agent (B))
Polyamine-based heat-latent curing agent (EH-4357S, manufactured by ADEKA Corporation, melting point: 80°C)
- Imidazole-based heat-latent curing agent (EH-4344S, manufactured by ADEKA Corporation, softening point: 110°C)
Dihydrazide-based heat-latent curing agent (ADH, manufactured by Nippon Finechem Co., Ltd., melting point: 180°C)

(Photocurable compound (C))
Bifunctional acrylic compound (Ebecryl 3700, manufactured by Daicel Allnex Corporation)
Acrylic modified epoxy resin (Neo Chemical Co., Ltd., BEAM-50, methacrylic modification ratio: 50%)
- Monofunctional acrylic resin (HOP-A, manufactured by Kyoei Chemical Co., Ltd.)
Bifunctional polybutadiene urethane acrylic resin (TE-2000, manufactured by Nippon Soda Co., Ltd., acrylic equivalent: 2000, number average molecular weight: 4000)

(Photopolymerization Initiator (D))
Oxime ester type (OXE-02, manufactured by BASF)
・α-Aminoketone type (visible light compatible, Omnipol-910, IGM)
Thioxanthone-based (visible light compatible, photopolymerization initiator prepared in Synthesis Example 1 below)
Anthraquinone-based (visible light compatible, photopolymerization initiator prepared in Synthesis Example 2 below)

(Synthesis Example 1)
Into a four-neck flask equipped with a stirrer, a nitrogen gas inlet tube, a reflux condenser, and a thermometer, 5.00 g (1.74 x 10 ^-2 moles) of 2-(2-hydroxyethylthio)-thioxanthen-9-one synthesized by a known method and 50 g of toluene were added and stirred at 80°C, and one drop of dibutyltin was added as a catalyst. Next, a solution in which 4.51 g of hexamethylene diisocyanate allophanate modified product (Takenate D-178NL, manufactured by Mitsui Chemicals, Inc., isocyanate equivalent 216.1 g/eq) was dissolved in 10 g of toluene was dropped over 30 minutes, and the mixture was stirred at 80°C for 3 hours under a nitrogen atmosphere. After the reaction was completed, the four-neck flask was allowed to cool at room temperature, and the solid component was separated. The collected solid component was thoroughly dried in an oven to obtain a thioxanthone-based photopolymerization initiator.

(Synthesis Example 2)
Into a four-neck flask equipped with a stirrer, a nitrogen gas inlet tube, a reflux condenser, and a thermometer, 5.0 g (1.76 x 10 ^-2 moles) of 2-(2-hydroxyethylthio)-9,10-anthraquinone and 150 g of toluene were added and stirred at 80°C, and then one drop of dibutyltin was added as a catalyst. Next, a solution in which 3.98 g of hexamethylene diisocyanate allophanate modified product (Mitsui Chemicals, Takenate D-178NL, isocyanate equivalent 216.1 g/eq) was dissolved in 10 g of toluene was added dropwise over 30 minutes, and the mixture was stirred at 80°C for 2 hours under a nitrogen atmosphere. After the reaction was completed, the four-neck flask was cooled in an ice bath, and the precipitated crystalline component was separated. The obtained crystalline component was mixed again with toluene, stirred at 100°C for 1 hour, and then cooled again with ice to remove impurities. The recovered crystalline component was thoroughly dried in an oven to obtain an anthraquinone-based photopolymerization initiator.

(Inorganic Filler (E))
Silica particles (SO-C1, manufactured by Admatechs Co., Ltd.)
Alumina particles (DAW-01, manufactured by Denka)

(Silane Coupling Agent (F))
Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)

(Core-shell type fine particles (G))
・Core-shell polymer (F351, manufactured by Aica Kogyo Co., Ltd.)

2. Preparation of resin composition (Example 1)
A resin composition was obtained by mixing the thermosetting compound (A) (CTBN-modified bisphenol A type epoxy compound), the latent thermosetting agent (B), the photocurable compound (C), the photopolymerization initiator (D), the inorganic filler (E), the core-shell type fine particles (F), and the silane coupling agent (G) in the mass ratio shown in Table 1 using a triple roll. In this example, this was used as a sealing agent.

(Examples 2 to 7 and Reference Examples 1 to 5)
A resin composition was prepared in the same manner as in Example 1, except that the composition was changed to that shown in Table 1.

(Checking moisture permeability)
The moisture permeability of each of the above resin compositions was confirmed by the following procedure. A release film was placed on a rectangular glass plate. Furthermore, a PET film piece (spacer) having a thickness of 100 μm was placed on the glass plate so as to surround the release film. Then, the resin composition prepared in the Examples and Reference Examples was applied onto the release film. Thereafter, a release film and a glass plate were further placed on the resin composition in this order, and the four sides were fixed with clips so as to sandwich the two glass plates. Then, light including visible light (light having a wavelength of 360 to 450 nm) was irradiated so that the accumulated light amount was 3000 mJ/cm ^2. The resin composition was further cured by heating at 120 ° C. for 1 hour. Thereafter, the glass plate and the release paper were removed, and a film (cured product of the resin composition) having a film thickness of 100 μm was obtained.
Using the obtained 100 μm film, an aluminum cup was prepared according to JIS Z0208:1976 and left in a high-temperature, high-humidity chamber at 60° C. and 90% RH for 24 hours. The moisture permeability was calculated from the mass before and after leaving the chamber using the following formula.
Moisture permeability (g/ ^m2 ·100μm·24h) = [weight of aluminum cup after standing for 24 hours (g) - weight of aluminum cup before standing for 24 hours (g)] / film area ( ^m2 )
Based on the calculated moisture permeability, the moisture resistance was evaluated according to the following criteria.

The adhesive strength of the cured resin composition was evaluated by the following method. The results are shown in Table 1.

To 100 parts by mass of the resin composition of each Example and each Reference Example, 2 parts by mass of polymer beads (Micropearl SP, manufactured by Sekisui Chemical Co., Ltd.) having an average particle size of 5 μm were added, and the polymer beads were dispersed in the resin composition by a planetary stirring device. Next, a resin composition in which the polymer beads were dispersed was applied using a screen printing plate to the center of a 25 mm x 45 mm glass substrate (EAGLE XG, manufactured by CORNING Co., Ltd.) on which a transparent electrode ITO and an alignment film NRB-W876 (manufactured by Nissan Chemical Co., Ltd.) had been previously formed, so that the diameter of the circle after lamination with a thickness of 5 μm was about 3.5 mm, and a seal pattern was formed. Next, another glass substrate was laminated under air so as to be perpendicular to the glass substrate on which the seal pattern was formed. Then, light including visible light (light with a wavelength of 370 to 450 nm) was irradiated so that the accumulated light amount was 3000 mJ / cm ² , and the resin composition was cured by heating at 120 ° C. for 1 hour to obtain a test piece.

A 0.5 mm portion of the test piece from the center end of the short side of the glass toward the center was vertically pressed in at a speed of 37.5 mm/min using an indentation tester (Model 210, manufactured by Intesco Co., Ltd.), and the stress at which the seal peeled off was measured. The value of the stress was taken as the adhesive strength. The adhesiveness was evaluated based on the following criteria.
◯: 1.1 N/mm or more △: Less than 1.1 N/mm and 1.0 N/mm or more ×: Less than 1.0 N/mm

As shown in Table 1 above, by combining a thermosetting compound (A) containing a rubber-modified epoxy compound (a), a latent heat curing agent (B) having a melting point of 110°C or less, a photocurable compound (C), and a photopolymerization initiator (D), it was possible to produce a sealing material having good adhesive strength despite having a moisture permeability of less than 100 g/ ^m2 (Examples 1 to 7).

This application claims priority from Japanese Patent Application No. 2023-053395, filed March 29, 2023. The entire contents of the specification of that application are incorporated herein by reference.

According to the present invention, a resin composition capable of forming a sealing material having high adhesive strength to a substrate and high moisture resistance, and a liquid crystal sealant containing the same can be obtained. Therefore, it is very useful for application to various display devices.

Claims (13)

A thermosetting compound (A);
A latent heat curing agent (B) having a melting point of 110° C. or less;
(C) a photocurable compound having an ethylenically unsaturated double bond in the molecule;
A photopolymerization initiator (D);
Including,
the thermosetting compound (A) is a resin composition containing a rubber-modified epoxy compound (a) having an epoxy group, an acrylonitrile-butadiene rubber structure, and a bisphenol A structure in one molecule;
The resin composition is applied to a thickness of 100 μm, irradiated with light having a wavelength of 370 nm or more and 450 nm or less so that the accumulated light amount is 3000 mJ/cm ² , and then heated at 120 ° C. for 1 hour to harden the film. The moisture permeability at 60 ° C., 90% Rh, and 24 hours measured in accordance with JIS Z0208:1976 is less than 100 g/m ² .
Resin composition. The average molecular weight of the rubber-modified epoxy compound (a) as determined by gel permeation chromatography is 2000 or less;
The resin composition according to claim 1. the amount of the rubber-modified epoxy compound (a) is 10 parts by mass or more and 25 parts by mass or less relative to 100 parts by mass in total of the thermosetting compound (A) and the photocurable compound (C);
The resin composition according to claim 1. The epoxy equivalent of the rubber-modified epoxy compound (a) is 300 or more and 1000 or less.
The resin composition according to claim 1. Further comprising an inorganic filler (E);
The resin composition according to claim 1. The inorganic filler (E) is at least one selected from the group consisting of silica, alumina, and talc.
The resin composition according to claim 5. The latent heat curing agent (B) is at least one selected from the group consisting of imidazole-based heat latent curing agents, amine adduct-based heat latent curing agents, and polyamine-based heat latent curing agents.
The resin composition according to claim 1. Further comprising a silane coupling agent (F);
The resin composition according to claim 1. Further comprising core-shell type fine particles (G),
The resin composition according to claim 1. The photopolymerization initiator (D) is at least one selected from the group consisting of oxime ester-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and anthraquinone-based photopolymerization initiators.
The resin composition according to claim 1. The resin composition according to any one of claims 1 to 10,
Liquid crystal sealant. The stress when subjected to the indentation test in the following test is 1.0 N/mm or more.
The liquid crystal sealant according to claim 11.
(Indentation test method)
(i) 2 parts by mass of polymer beads for spacers (Micropearl SP, manufactured by Sekisui Chemical Co., Ltd.) having an average particle size of 5 μm are dispersed in 100 parts by mass of the liquid crystal sealant.
(ii) A pair of 25 mm x 45 mm glass substrates (EAGLE XG, manufactured by Corning) having a transparent electrode made of ITO and an alignment film arranged thereon are prepared, and the liquid crystal sealant having the polymer beads dispersed therein is applied to the center of one of the glass substrates to a diameter of 3.5 mm and a thickness of 5 μm.
(iii) The other glass substrate is placed on top of the above-mentioned liquid crystal sealant.
(iv) Irradiate with light having a wavelength of 360 to 450 nm so that the cumulative light amount is 3000 mJ/ ^cm2 , and cure at 120°C for 1 hour.
(v) The stress is measured when a portion of the other short side of the glass substrate, extending 0.5 mm from the central end toward the center, is pressed in at a speed of 37.5 mm/min using an indentation tester. A pair of substrates;
An alignment film sandwiched between the pair of substrates;
a liquid crystal layer sandwiched between the pair of alignment films;
a sealant for sealing the liquid crystal layer;
A liquid crystal display panel comprising:
The sealing material is a cured product of the liquid crystal sealant according to claim 11.
LCD display panel.