JP7536999B2 - Liquid crystal sealant, method for producing liquid crystal display panel, and liquid crystal display panel - Google Patents

Description

The present invention relates to a liquid crystal sealant, a method for manufacturing a liquid crystal display panel, and a liquid crystal display panel.

Liquid crystal and organic electroluminescence (EL) display panels are widely used as image display panels for various electronic devices, including mobile phones and personal computers. For example, a liquid crystal display panel has two transparent substrates with electrodes on their surfaces, a frame-shaped sealant sandwiched between them, and a liquid crystal material sealed within the area surrounded by the sealant.

In order to manufacture liquid crystal display panels that are highly resistant to impacts such as those caused by being dropped, it is necessary to develop a highly flexible sealing agent that can absorb the stress caused by such impacts.

For example, Patent Document 1 describes a sealant for liquid crystal dropping method, which contains a curable resin, a polymerization initiator, and a heat curing agent (dihydrazide type), and in which the storage modulus of the cured product at 25°C is less than 0.8 GPa and the storage modulus of the cured product at 121°C is 0.01 GPa or more. According to Patent Document 1, impact resistance can be improved by making the storage modulus of the cured product at 25°C less than 0.8 GPa, and moist heat resistance can be improved by making the storage modulus of the cured product at 121°C 0.01 GPa or more. Specifically, Patent Document 1 describes that the above storage modulus can be achieved by making the curable resin contain a compound having an epoxy group and a rubber structure.

Patent Document 2 describes a sealant for liquid crystal dropping method, which contains a curable resin and a polymerization initiator or a heat curing agent (dihydrazide type), and in which the storage modulus of the cured product at 25°C is less than 2.0 GPa, and the loss modulus of the cured product at 25°C is 0.1 GPa or more and 1.0 GPa or less. According to Patent Document 2, by lowering the storage modulus of the cured product and setting the loss modulus to a certain level or more, the cured product becomes easy to deform and is easy to restore its shape (plastic deformation becomes difficult to occur), so that the impact resistance of the cured product can be increased while preventing peeling and deformation even if the substrate is repeatedly deformed. Specifically, Patent Document 2 describes that the storage modulus and loss modulus can be achieved by using a compound having a polymerizable functional group and a rubber structure as the curable resin, or by blending rubber particles into the sealant.

Patent Document 3 describes a liquid crystal sealant for the liquid crystal dropping method, which contains a compound having an epoxy group and an acryloyl group in the molecule, has a glass transition temperature of 90°C or less and a tan δ of 0.5 or more as measured by the DMA method. Patent Document 3 also describes that a dihydrazide-based heat curing agent is used. Patent Document 3 also describes that the above sealant has improved flexibility after curing, and can achieve sufficient adhesive strength even in flexible displays and displays with curved shapes.

Patent Document 4 describes a sealant for liquid crystal dropping method, which contains a curable resin, a polymerization initiator or a heat curing agent, and an inorganic filler having a hydrophobic group on the surface in an amount of 15% by mass or more, and the storage modulus of the cured product at 25°C is 2.0 GPa or less. Patent Document 2 describes that by making the storage modulus of the cured product at 25°C 2.0 GPa or less, it is possible to prevent panel peeling when the liquid crystal display element is subjected to impact due to being dropped, etc. Patent Document 2 describes that a compound having a flexible skeleton such as a ring-opening structure of a cyclic lactone is preferable as the curable resin.

International Publication No. 2020/085081 International Publication No. 2018/124023 JP 2018-022054 A International Publication No. 2018/207730

[Problem related to the first disclosure]
As described in Patent Documents 1 to 5, various sealants with improved flexibility after curing (reduced Young's modulus) have been researched in order to improve resistance to impacts such as dropping. In recent years, there has been a demand for thinner liquid crystal display panels, and in order to achieve this, the glass plate that is the substrate may be polished to make it thinner after the sealant is cured. It is expected that improved flexibility will reduce stress and abrasion on the members inside the liquid crystal display panel, making it possible to further reduce the thickness of the liquid crystal display panel.

However, the inventors have newly discovered that when a liquid crystal display panel having a hardened sealant is subjected to pressure treatment such as polishing, the heat-hardening agent seeps out of the sealant, causing bright spots to appear in the liquid crystal (roughness), resulting in a problem of degraded display characteristics.

The first disclosure of this specification has been made in consideration of the above-mentioned problems, and has an object to provide a liquid crystal sealant that has a low Young's modulus of the cured product and that can suppress the occurrence of roughness when a liquid crystal display panel having the cured liquid crystal sealant is subjected to a pressure treatment, a method for manufacturing a liquid crystal display panel using the liquid crystal sealant, and a liquid crystal display panel manufactured using the liquid crystal sealant.

One aspect of the present invention for solving the problems related to the first disclosure of the above specification relates to a liquid crystal sealant, the cured product of which has a Young's modulus of 0.5 GPa or more and less than 3.0 GPa measured at 23°C, and which comprises a thermosetting compound (A) having an epoxy group in the molecule, and a thermosetting agent (E), the thermosetting agent (E) being a thermosetting agent having a solubility in water at 20°C of 5 g/100 g or less.

One aspect of the present invention for solving the problem related to the second disclosure of the above specification relates to a liquid crystal sealant, in which a cured product has an elongation of 30% or more measured at 23°C, and a cured product having a thickness of 0.6 mm has a moisture permeability of less than 50 g/ ^m2 in an environment of 60°C and 90Rh.

Another aspect of the present invention for solving the above problem relates to a method for manufacturing a liquid crystal display panel, comprising the steps of: applying the liquid crystal sealant onto an alignment film of one of a pair of substrates, each substrate having an alignment film, to form a seal pattern; dripping liquid crystal onto the one substrate and within the area of the seal pattern or onto the other substrate while the seal pattern is in an uncured state; overlapping the one substrate and the other substrate via the seal pattern; and curing the seal pattern.

Another aspect of the present invention for solving the above problem relates to a liquid crystal display panel including a pair of substrates each having an alignment film, a frame-shaped sealing member disposed between the alignment films of the pair of substrates, and a liquid crystal layer filled in the space surrounded by the sealing member between the pair of substrates, wherein the sealing member is a cured product of the liquid crystal sealant.

According to the present invention, there is provided a liquid crystal sealant which has a low Young's modulus of the cured product and which can suppress the occurrence of roughness when a liquid crystal display panel having the cured liquid crystal sealant is subjected to a pressure treatment, a method for manufacturing a liquid crystal display panel using said liquid crystal sealant, and a liquid crystal display panel manufactured using said liquid crystal sealant.

In this specification, "(meth)acrylate" means acrylate or methacrylate, "(meth)acryloyl group" means acryloyl group or methacryloyl group, "(meth)acrylic acid" means acrylic acid or methacrylic acid, and "(meth)acrylic acid resin" means acrylic resin or methacrylic resin.

1. Liquid Crystal Sealing Agent One embodiment of the present invention relates to a sealing agent (hereinafter, also simply referred to as "sealing agent") for sealing liquid crystal in a liquid crystal display panel.

1-1. Materials First, materials that can be commonly used in the liquid crystal sealants according to each disclosure in this specification will be described. The liquid crystal sealants described in each disclosure can be used by appropriately selecting and combining the following materials so as to satisfy the conditions in each disclosure. Furthermore, these materials are not essential materials for the liquid crystal sealants described in each disclosure, and various combinations of materials are allowed as long as the conditions in each disclosure are satisfied.

1-1-1. Curable resin 1-1-1-1. Thermosetting compound (A) having an epoxy group in the molecule
The liquid crystal sealant according to each of the above disclosures may contain, as a curable resin, a thermosetting compound (A) having two or more epoxy groups in the molecule. Note that, in this specification, the thermosetting compound (A) does not include partial epoxy (meth)acrylates described later.

The thermosetting compound (A) may be any one of a monomer, an oligomer, or a polymer. The thermosetting compound (A) can further reduce the moisture permeability of the cured product, improve the display characteristics of the resulting liquid crystal panel, and improve the reliability of the liquid crystal display panel.

The thermosetting compound (A) preferably has a weight average molecular weight of 500 or more and 10,000 or less, more preferably 500 or more and 5,000 or less. The weight average molecular weight of the thermosetting compound (A) is measured in terms of polystyrene by gel permeation chromatography (GPC).

The thermosetting compound (A) is preferably a compound having an aromatic ring. Examples of epoxy compounds having an aromatic ring include aromatic polyhydric glycidyl ether compounds obtained by reacting epichlorohydrin with aromatic diols such as bisphenol A, bisphenol S, bisphenol E, bisphenol F, bisphenol AD, or diols obtained by modifying these aromatic diols with ethylene glycol, propylene glycol, alkylene glycol, etc., novolac resins derived from phenol or cresol and formaldehyde, polyphenols such as polyalkenylphenols and their copolymers, and novolac-type polyhydric glycidyl ether compounds obtained by reacting epichlorohydrin with xylylene phenol resins. Among them, 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 thermosetting resin composition (A) may contain only one type of epoxy compound, or may contain two or more types of epoxy compounds.

In Patent Document 1 and Patent Document 3, the flexibility of the cured product is increased by using an epoxy compound having a structure (rubber structure) with an unsaturated bond or siloxane structure in the molecule. However, according to the new findings of the present inventors, the compound having the rubber structure is likely to dissolve in the liquid crystal and is likely to cause contamination of the liquid crystal. Therefore, it is preferable that the thermosetting compound (A) has substantially no unsaturated bonds or siloxane structures in the molecule. Specifically, the content of unsaturated bonds or siloxane structures in the molecule is preferably 5% by mass or less, more preferably 1% by mass or less.

The thermosetting compound (A) may be liquid or solid. From the viewpoint of further reducing the moisture permeability of the cured product, a solid epoxy compound is preferred. The softening point of the 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 (1986).

1-1-1-2. Specific curable compound (B)
The liquid crystal sealant according to each of the above disclosures may contain, as a curable resin, a curable resin (B) having a characteristic ratio of 4.70 or less, a Tg of 250° C. or more and 340° C. or less, and a weight average molecular weight (Mw) of 1,000 or more.

The above characteristic ratio is a value that represents the flexibility of the molecule, and the smaller the ratio, the more rounded the parameter is.

In formula (1), <R ₀ ² > is the root mean square value of all possible end-to-end distances of the polymer chain, L is the root mean square value of the lengths of each structural unit constituting the polymer chain, and n is the number of structural units.

A curable compound (B) having the above characteristic ratio of 4.70 or less can have a stable structure in a curled state compared to other resins. Therefore, the specific curable compound (B) is usually in a curled state, but can be stretched when stress is applied to the cured product of the sealant. And, since the specific curable compound (B) has a large state change between the curled state and the stretched state, it is easy to expand and contract even after curing, and is thought to increase the flexibility and extensibility of the cured product of the liquid crystal sealant. In addition, by ensuring flexibility and extensibility with the specific curable compound (B), even if other materials or a compound having a structure in the molecule that is difficult to permeate moisture is used as the specific curable compound (B), the flexibility and extensibility of the cured product are not easily impaired. From the above viewpoint, the characteristic ratio of the specific curable compound (B) is preferably 4.70 or less, and more preferably 4.50 or less. The upper limit of the characteristic ratio of the specific curable compound (B) is not particularly limited, but from the viewpoint of more stable viscosity, it is preferably 4.30 or more.

The above characteristic ratios can be values calculated by the Bicerano method. The Bicerano method is a method for calculating predicted resin properties described in "Prediction of Polymer Properties" by Joseph Bicerano, Marcel Dekker, New York, 2002.

The specific curable compound (B) may be, for example, a resin having hydrogen bonds in the molecule, a resin having an ortho-substituted aromatic ring, or a resin having a keto group in the repeating structural portion.

The specific curable compound (B) may be any curable compound such as a photocurable compound or a thermosetting compound, but is preferably a photocurable compound from the viewpoint of suppressing contamination of the liquid crystal due to elution into the liquid crystal during curing of the sealant by heating. The specific curable compound (B) as the photocurable compound is more preferably a compound having an ethylenically unsaturated double bond in the molecule (excluding partial epoxy (meth)acrylate), and is even more preferably a compound having a (meth)acryloyl group due to its high reactivity.

It is preferable that the above specific curable compound (B) is a curable compound represented by the following general formula (2):

・・・一般式（２）

...General formula (2)

In general formula (2), _R1 represents a divalent residue derived from a polyepoxy compound, _R2 independently represents a divalent structure obtained by ring-opening a cyclic lactone, _R3 independently represents a linear or branched alkylene group having 1 to 6 carbon atoms, and _R4 independently represents a hydrogen atom or a methyl group.

R ₁ is a divalent residue derived from a polyfunctional epoxy compound. Examples of the polyfunctional epoxy compound include:
bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol E type epoxy resins, and bisphenol F type epoxy resins;
Hydrogenated bisphenol epoxy resin,
Novolac epoxy resin,
Biphenyl type epoxy resin,
Stilbene type epoxy resin,
Hydroquinone type epoxy resin,
Naphthalene-based epoxy resins,
Tetraphenylolethane type epoxy resin,
Trishydroxyphenylmethane type epoxy resin,
Dicyclopentadiene phenol type epoxy resin,
alicyclic epoxy resins such as 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol;
polyglycidyl esters of polybasic acids, such as the diglycidyl ester of hexahydrophthalic anhydride;
glycidyl ethers such as sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polypropylene glycol diglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and cyclohexanedimethanol diglycidyl ether;
Diene polymer type epoxy resins such as polybutadiene or polyisoprene,
glycidylamine-based epoxy resins such as tetraglycidyldiaminodiphenylmethane, tetraglycidylbisaminomethylcyclohexane, diglycidylaniline, and tetraglycidylmetaxylylenediamine;
Heterocycle-containing epoxy resins such as triazine or hydantoin;
etc.

From the viewpoint of further improving the adhesiveness and heat resistance of the sealing agent, R ₁ is preferably a divalent structure represented by the following general formula (2).

・・・一般式（２）

...General formula (2)

In general formula (2), X represents a single bond, a methylene group, a methylmethylene group, a dimethylmethylene group, a methylphenylmethylene group, a cyclohexylidene group, a sulfonyl group, an ether bond, or a thioether bond.

Furthermore, from the viewpoint of further increasing the flexibility of the cured product (reducing the Young's modulus), it is preferable that X in general formula (2) is a methylene group.

R ₂ is a divalent structure obtained by ring-opening a cyclic lactone. The type of the cyclic lactone is not particularly limited, but is preferably a cyclic lactone having 2 to 6 carbon atoms, and more preferably a cyclic lactone having 4 to 6 carbon atoms. Examples of such cyclic lactones include α-acetolactone (2 carbon atoms), β-propiolactone (3 carbon atoms), γ-butyrolactone (4 carbon atoms), δ-valerolactone (5 carbon atoms), and ε-caprolactone (6 carbon atoms). R ₂ may be substituted. Among these, from the viewpoint of increasing the elasticity of the curable compound and increasing the flexibility of the sealing agent (reducing the Young's modulus), R ₂ is preferably a structure derived from β-propiolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone, and more preferably a structure derived from γ-butyrolactone, δ-valerolactone, and ε-caprolactone.

Specifically, _R2 is a divalent structure represented by the following general formula (3).

・・・一般式（３）

...General formula (3)

In general formula (3), Y is an alkylene group having 2 or more and 6 or less carbon atoms, preferably 3 or more and 6 or less carbon atoms, and more preferably 4 or more and 6 or less carbon atoms.

Y may be substituted. Examples of the substituent include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

In addition, _R2 may be a repeat of a divalent structure obtained by ring-opening the above cyclic lactone (a divalent structure represented by general formula (3)). In this case, the number of repeats is not particularly limited, but is preferably 1 to 6, and more preferably 1 to 5.

_R3 is a linear or branched alkylene group having 1 to 6 carbon atoms. Examples of the alkylene group include an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, a pentyl group, and a hexyl group. Of these, from the viewpoint of further reducing the moisture permeability of the sealing agent, _R3 is preferably an ethyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group, and more preferably an ethyl group, a propyl group, or an isopropyl group.

Y may be substituted. Examples of the substituent include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

_R4 is a hydrogen atom or a methyl group.

The curable compound represented by general formula (2) is a bifunctional (meth)acrylic resin having a repeating structure with a keto group and an ortho-substituted benzene ring. According to the findings of the present inventors, the curable compound represented by general formula (2) having such a structure is more likely to increase the characteristic ratio. Furthermore, since the curable compound represented by general formula (2) has a relatively large molecular weight, it is less likely to dissolve in the liquid crystal, and therefore it is easy to suppress contamination of the liquid crystal caused by the sealant dissolving into the liquid crystal.

The curable compound represented by formula (2) can be synthesized by a known method. For example, a reaction flask is charged with a (meth)acrylate having a hydroxyl group, phthalic anhydride, and a cyclic lactone, and these are reacted while stirring under reflux while feeding dry air in the presence of a polymerization inhibitor, and then a polyfunctional epoxy compound is added and reacted while stirring under reflux while feeding dry air, thereby synthesizing the curable compound represented by formula (2).

The specific curable compound (B) has a weight average molecular weight (Mw) of 1000 or more. The weight average molecular weight (Mw) is preferably 1000 or more and 2000 or less, more preferably 1200 or more and 1800 or less, and even more preferably 1400 or more and 1600 or less. When the Mw of the specific curable compound (B) is 1000 or more, the flexibility of the cured product can be further improved (Young's modulus can be reduced more than decreased), and the elongation of the cured product can be further increased. When the Mw of the specific curable compound (B) is 2000 or less, the moisture permeability of the sealant can be further reduced. The Mw of the specific curable compound (B) is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard.

The specific curable compound (B) has a glass transition temperature (Tg) of 250°C or higher and 340°C or lower, preferably 260°C or higher and 320°C or lower, and more preferably 280°C or higher and 310°C or lower. If the glass transition temperature is 250°C or higher, the moisture permeability can be reduced. If the glass transition temperature is 340°C or lower, the cured product of the liquid crystal sealant can be made more flexible.

1-1-1-3. Other curable compounds (C)
The above-mentioned sealant may contain other curable compounds (C) as a curable resin. The other curable compounds (C) may be any curable compounds such as photocurable compounds and thermosetting compounds. Examples of the other curable compounds (C) include compounds having an ethylenically unsaturated double bond in the molecule (excluding partial epoxy (meth)acrylate).

The other curable compound (C) may be any of a monomer, an oligomer, or a polymer. Examples of the other curable compound (C) include a compound having a (meth)acryloyl group in the molecule. The number of (meth)acryloyl groups per molecule of the compound having a (meth)acryloyl group may be one or two or more.

Examples of curable compounds containing one (meth)acryloyl group per molecule include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate.

Examples of curable compounds having two or more (meth)acryloyl groups in one molecule include di(meth)acrylates derived from polyethylene glycol, propylene glycol, and polypropylene glycol, di(meth)acrylates derived from tris(2-hydroxyethyl)isocyanurate, di(meth)acrylates derived from a diol obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol, di(meth)acrylates derived from a diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A or bisphenol F, di- or tri(meth)acrylates derived from a polyol obtained by adding 2 or 3 moles of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane, di(meth)acrylates derived from a diol 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 tri(meth)acrylate or its oligomer, pentaerythritol tri(meth)acrylate or its oligomer, poly(meth)acrylate of dipentaerythritol, tris(acryloxyethyl)isocyanurate, caprolactone-modified tris(acryloxyethyl)isocyanurate, caprolactone-modified tris(methacryloxyethyl)isocyanurate, poly(meth)acrylate of alkyl-modified dipentaerythritol, poly(meth)acrylate of caprolactone-modified dipentaerythritol, neopentyl glycol hydroxypivalate di(meth)acrylate, caprolactone-modified neopentyl glycol hydroxypivalate di(meth)acrylate, ethylene oxide-modified phosphate (meth)acrylate, ethylene oxide-modified alkylated phosphate (meth)acrylate, and oligo(meth)acrylates of neopentyl glycol, trimethylolpropane, and pentaerythritol.

As described above, compounds having a structure (rubber structure) with an unsaturated bond or siloxane structure in the molecule are likely to dissolve in the liquid crystal and cause contamination of the liquid crystal. In addition, photocurable compounds having the above-mentioned rubber structure tend to reduce the flexibility of the curing rate compared to other photocurable compounds. Therefore, it is preferable that the other curable compounds (C) have substantially no unsaturated bonds or siloxane structures in the molecule. Specifically, the content of unsaturated bonds or siloxane structures in the molecule is preferably 5% by mass or less, more preferably 1% by mass or less.

1-1-1-4. Partial epoxy (meth)acrylate (D)
The sealing agent may contain a partial epoxy (meth)acrylate (D) as a curable resin. The partial epoxy (meth)acrylate (D) can increase the adhesion of the cured product of the sealing agent to a substrate.

Partial epoxy (meth)acrylate (D) is a compound having both epoxy and (meth)acryloyl groups in the molecule, and is a partially (meth)acryloyl-modified epoxy resin in which at least one epoxy group among the epoxy groups of a bifunctional or higher epoxy resin is modified with a (meth)acryloyl group. Partial epoxy (meth)acrylate (D) can be obtained by a known method, for example, a method of reacting a bifunctional or higher epoxy resin with (meth)acrylic acid in the presence of a basic catalyst.

The epoxy resin used as the raw material for the partial epoxy (meth)acrylate (D) may be any epoxy resin having two or more epoxy groups in the molecule. Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type, bisphenol F type, 2,2'-diallyl bisphenol A type, bisphenol AD type, and hydrogenated bisphenol type, novolac type epoxy resins such as phenol novolac type, cresol novolac type, biphenyl novolac type, and trisphenol novolac type, biphenyl type epoxy resins, and naphthalene type epoxy resins.

Of these, bisphenol type epoxy resins such as bisphenol A type and bisphenol F type are preferred because they have low crystallinity and high coating stability.

The epoxy resin may be trifunctional, tetrafunctional, or even more functional epoxy resin. However, bifunctional epoxy resins are preferred from the viewpoint of appropriately adjusting the crosslink density and appropriately increasing the adhesive strength of the cured product to the substrate.

In the partial epoxy (meth)acrylate (D), the ratio of the number of moles of (meth)acryloyl groups to the number of moles of epoxy groups is preferably at least 1, and more preferably at least 2. By increasing the ratio of the number of moles of (meth)acryloyl groups, it is easier to suppress contamination of the liquid crystal caused by the sealant dissolving into the liquid crystal.

It is preferable that the partial epoxy (meth)acrylate (D) has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 300 or more and 500 or less.

1-2. Heat curing agent (E)
The sealing agent may contain a thermosetting agent (E) for curing the thermosetting components such as the thermosetting compound (A), other curable compounds (C), and partial epoxy (meth)acrylate (D).

The heat curing agent (E) is preferably a latent heat curing agent. A latent heat curing agent is a compound that does not cure the heat curing compound (A) or other curable compounds (C) under normal storage conditions (room temperature, visible light, etc.), but cures these compounds when exposed to heat. The heat curing agent (E) is preferably a curing agent capable of curing epoxy compounds (hereinafter also referred to as "epoxy curing agent").

From the viewpoint of increasing the viscosity stability of the photothermosetting resin composition and not impairing the moisture resistance of the cured product, the epoxy curing agent preferably has a melting point of 50°C or higher and 250°C or lower, more preferably a melting point of 100°C or higher and 200°C or lower, and even more preferably a melting point of 150°C or higher and 200°C or lower.

Examples of epoxy curing agents include dihydrazide-based heat-latent curing agents, imidazole-based heat-latent curing agents, dicyandiamide-based heat-latent curing agents, amine adduct-based heat-latent curing agents, and polyamine-based heat-latent curing agents. Of these, dihydrazide-based heat-latent curing agents, imidazole-based heat-latent curing agents, amine adduct-based heat-latent curing agents, and polyamine-based heat-latent curing agents are preferred, and from the viewpoint of further improving the display characteristics, imidazole-based heat-latent curing agents, amine adduct-based heat-latent curing agents, and polyamine-based heat-latent curing agents are more preferred, and amine adduct-based heat-latent curing agents and polyamine-based heat-latent curing agents are even more preferred.

Examples of dihydrazide-based thermal latent curing agents include adipic dihydrazide (melting point 181°C), 1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin (melting point 120°C), 7,11-octadecadiene-1,18-dicarbohydrazide (melting point 160°C), dodecanedioic dihydrazide (melting point 190°C), and sebacic dihydrazide (melting point 189°C).

Examples of imidazole-based thermal latent curing agents include 2,4-diamino-6-[2'-ethylimidazolyl-(1')]-ethyltriazine (melting point 215-225°C) and 2-phenylimidazole (melting point 137-147°C).

Examples of dicyandiamide-based thermal latent curing agents include dicyandiamide (melting point 209°C).

Amine adduct-based thermal latent curing agents are thermal latent curing agents consisting of an addition compound obtained by reacting an amine compound having catalytic activity with any compound. Examples of amine adduct-based thermal latent curing agents include AmiCure PN-40 (melting point 110°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure PN-50 (melting point 120°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure PN-23 (melting point 100°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure PN-31 (melting point 115°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure PN-H (melting point 115°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure MY-24 (melting point 120°C) manufactured by Ajinomoto Fine Techno Co., Ltd., and AmiCure MY-H (melting point 131°C) 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 amine with epoxy. Examples include ADEKA HARDENER EH4339S (softening point 120-130°C) manufactured by ADEKA Corporation, and ADEKA HARDENER EH4357S (softening point 73-83°C) manufactured by ADEKA Corporation.

1-3. Photopolymerization initiator (F)
The above-mentioned sealing agent may contain a photopolymerization initiator (F) for initiating the curing (polymerization) of a photocurable component such as a specific curable compound (B), other curable compounds (C), partial epoxy (meth)acrylate (D), etc.

The photopolymerization initiator (F) is not particularly limited as long as it is a compound that can initiate the curing (polymerization) of these compounds. For example, the photopolymerization initiator (F) can be a radical polymerization initiator, and may be a self-cleaving photopolymerization initiator or a hydrogen-drawing inorganic photopolymerization initiator.

Examples of self-cleaving photopolymerization initiators include alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, acetophenone compounds, phenyl glyoxylate compounds, benzoin ether compounds, and oxime ester compounds. Examples of the alkylphenone compounds include benzyl dimethyl ketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one (IRGACURE 651, manufactured by BASF), α-aminoalkylphenones such as 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one (IRGACURE 907, manufactured by BASF), and α-hydroxyalkylphenones such as 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE 184, manufactured by BASF). Examples of the acylphosphine oxide compounds include 2,4,6-trimethylbenzoin diphenylphosphine oxide. Examples of the titanocene compounds include bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium. Examples of the acetophenone compounds include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 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. Examples of the phenyl glyoxylate compounds include methylphenyl glyoxyester. Examples of the benzoin ether compounds include benzoin, benzoin methyl ether, and benzoin isopropyl ether, etc. Examples of the oxime ester compounds include 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzoyloxime)] (IRGACURE OXE01, manufactured by BASF), and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (IRGACURE OXE02, manufactured by BASF), etc.

Examples of hydrogen abstraction type photopolymerization initiators include benzophenone compounds, thioxanthone compounds, anthraquinone compounds, and benzyl compounds. Examples of the benzophenone compounds include benzophenone, o-benzoylbenzoic acid methyl-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. Examples of the thioxanthone compounds include thioxanthone, 2-chlorothioxanthone, 1-chloro-4-propoxythioxanthone, 1-chloro-4-ethoxythioxanthone (Speedcure CPTX, manufactured by Lambson Limited), 2-isopropylxanthone (Speedcure ITX, manufactured by Lambson Limited), 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone (Speedcure DETX, manufactured by Lambson Limited), 2,4-dichlorothioxanthone, and (2-carboxymethoxythioxanthone)-(polytetramethylene glycol 250) diester (Omnipol TX, manufactured by IGM). Examples of the anthraquinone compounds include 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone, 2-hydroxyanthraquinone (2-Hydroxyanthraquinone, manufactured by Tokyo Chemical Industry Co., Ltd.), 2,6-dihydroxyanthraquinone (Anthraflavic Acid, manufactured by Tokyo Chemical Industry Co., Ltd.), and 2-hydroxymethylanthraquinone (2-(Hydroxymethyl)anthraquinone, manufactured by Junsei Chemical Co., Ltd.).

The absorption wavelength of the photopolymerization initiator (F) is not particularly limited, and it can be, for example, a photopolymerization initiator that absorbs light with a wavelength of 360 nm or more. In particular, it is more preferable that the photopolymerization initiator absorbs light in the visible light region, and a photopolymerization initiator that absorbs light with a wavelength of 360 nm or more and 780 nm or less is even more preferable, and a photopolymerization initiator that absorbs light with a wavelength of 360 nm or more and 430 nm or less is particularly preferable.

Examples of photopolymerization initiators that absorb light with wavelengths of 360 nm or more include alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, thioxanthone compounds, and anthraquinone compounds. Of these, oxime ester compounds are preferred.

The molecular weight of the photopolymerization initiator (F) can be, for example, 200 or more and 5000 or less. If the molecular weight of the photopolymerization initiator (F) is 200 or more, the photopolymerization initiator (F) is less likely to dissolve into the liquid crystal. On the other hand, if the molecular weight of the photopolymerization initiator (F) is 5000 or less, the compatibility with various curable resins is increased, and the curing property of the sealant is likely to be good. The molecular weight of the photopolymerization initiator (F) 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 (F) 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 (F) in THF (tetrahydrofuran), and a high performance liquid chromatography (HPLC) measurement is performed. The area percentage of the detected peaks (the ratio of the area of each peak to the total area of all peaks) is then calculated, and the presence or absence of a main peak is confirmed. The main peak is the peak with the highest 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).

1-4. Inorganic filler (G)
The sealing agent may contain an inorganic filler (G). The inorganic filler (G) not only imparts a predetermined hardness and linear expansion property to the cured product, but also prevents moisture and the like from penetrating the inside of the cured product. This suppresses the permeation of moisture and further reduces the moisture permeability of the cured product.

Examples of inorganic fillers (G) include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, titanium nitride, aluminum oxide (alumina), zinc oxide, silicon dioxide (silica), potassium titanate, kaolin, talc, glass beads, sericite activated clay, bentonite, aluminum nitride, and silicon nitride. Of these, silicon dioxide and talc are preferred.

The shape of the inorganic filler (G) may be regular, such as spherical, plate-like, or needle-like, or may be irregular. When the inorganic filler (G) is spherical, the average primary particle size of the inorganic filler (G) is preferably 1.5 μm or less. In addition, the specific surface area of the inorganic filler (G) 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 (F) can be measured by the laser diffraction method described in JIS Z8825 (2013). The specific surface area of the filler can be measured by the BET method described in JIS Z8830 (2013).

1-5. Others In addition to the above-mentioned components, the sealing agent may contain a thermal radical generator, organic fine particles, a coupling agent such as a silane coupling agent, an ion trapping agent, an ion exchange agent, a leveling agent, a pigment, a dye, a sensitizer, a plasticizer, and a defoaming agent.

Examples of the thermal radical polymerization initiator include organic peroxides, azo compounds, benzoins, benzoin ethers, and acetophenones.

The organic fine particles can reduce residual stress when the sealant is applied. For example, the organic fine particles can have an elastic core containing conjugated diene rubber and silicone rubber, and an outer shell made of a polymer such as (meth)acrylate, vinyl monomer, and epoxy monomer that enhances compatibility with other components.

Examples of the above silane coupling agents include vinyltrimethoxysilane, gamma-(meth)acryloxypropyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, and gamma-glycidoxypropyltriethoxysilane.

In addition, the above-mentioned sealing agent may further contain spacers, etc. for adjusting the gap of the liquid crystal display panel.

2. Description of Liquid Crystal Sealant Regarding Each Disclosure 2-1. First Disclosure 2-1-1. Description of Liquid Crystal Sealant The first disclosure in this specification relates to a liquid crystal sealant that has a low Young's modulus of a cured product and can suppress the occurrence of roughness when a liquid crystal display panel having the cured liquid crystal sealant is subjected to a pressure treatment.

The sealant has a Young's modulus of 0.5 GPa or more and less than 3.0 GPa when measured at 23°C, and a thermosetting compound (A) having an epoxy group in the molecule, and a thermosetting agent (E) having a solubility in water of 5 g/100 g or less at 20°C. The Young's modulus is preferably 0.5 GPa or more and 2.0 GPa or less, more preferably 0.5 GPa or more and 1.5 GPa or less, and even more preferably 0.5 GPa or more and 1.0 GPa or less. By being in the above range, the flexibility of the sealant can be further increased, the drop resistance of the liquid crystal display panel can be increased, and the moisture permeability can be reduced, thereby increasing the reliability of the liquid crystal display panel.

Specifically, the above Young's modulus is the Young's modulus measured by the following method.

The sealant is applied to a release paper with a thickness of 100 μm using an applicator. The applied sealant is then placed in a nitrogen replacement container and purged with nitrogen for 5 minutes, after which it is irradiated with light of 3000 mJ/cm ² (light calibrated with a 365 nm wavelength sensor) and further heated at 120° C. for 1 hour to produce a cured film.

The obtained cured film was cut into strips (length 150 mm, width 10 mm) and then a tensile test was performed at room temperature (23°C) at a test speed of 10 mm/min using an autograph tensile testing machine (Shimadzu Corporation, AG-X), and Young's modulus was calculated from the slope of the stress and strain in the elastic region.

A sealant having the above Young's modulus can be prepared by various methods. For example, the above characteristics can be imparted to the sealant by using an epoxy resin containing silicone, an epoxy resin having polyethylene glycol or polypropylene glycol, an epoxy resin having a urethane bond, an epoxy resin having a rubber structure, or the like as the thermosetting compound (A) and adjusting the content ratio. Alternatively, the above characteristics can be imparted to the sealant by using a resin having a relatively long alkyl group or a flexible compound having an aromatic ring in the molecule.

As mentioned above, a sealant with a low Young's modulus of the cured product has the property that the cured product is less likely to crack when pressure treatment is applied after curing. Therefore, a sealant with a Young's modulus of the cured product in the above range is useful for applications in which pressure treatment is applied after curing, such as polishing the substrate to thin the liquid crystal display panel. On the other hand, liquid crystal display panels that have been pressure treated after curing may have bright spots in the liquid crystal (roughness) caused by the heat curing agent seeping out of the sealant. On the other hand, liquid crystal display panels that have not been pressure treated do not have roughness.

The inventors of the present invention considered that the above-mentioned roughness occurs due to the following mechanism. That is, when manufacturing a liquid crystal display panel, a pattern made of uncured sealant and liquid crystal is formed on a substrate, and another substrate is superimposed on it, and then the sealant is cured. During this process, after forming a pattern made of sealant and liquid crystal, a small amount of moisture in the atmosphere may enter the liquid crystal during the idling time before superimposing another substrate. If another substrate is superimposed in this state and the sealant is cured by heating, the heat curing agent in the sealant will seep into the liquid crystal. In the past, it was considered good to use a hydrophilic material as the heat curing agent to suppress the seepage into the hydrophobic liquid crystal. However, if a hydrophilic heat curing agent is used, the heat curing agent, whose mobility has improved during heating, will be attracted to the moisture in the liquid crystal and will seep into the liquid crystal. It is thought that this seeped heat curing agent will gather in the liquid crystal due to pressure treatment or vibration during polishing, and become a bright spot (roughness).

Of the above mechanisms, it is believed that the occurrence of bright spots (roughness) can be suppressed by suppressing the attraction of the heat curing agent by the moisture in the liquid crystal. Based on this idea, in this disclosure, a hydrophobic heat curing agent that satisfies the condition of a solubility in water of 5 g/100 g or less at 20°C is used as the heat curing agent (E).

The solubility of the thermosetting agent (E) is a value measured as follows. 100 g of water and a specified amount of curing agent are placed in a 300 mL beaker and mixed and stirred for 2 hours, after which the state where it becomes transparent to the naked eye is judged to be dissolved. Then, the amount of thermosetting agent (E) added to the water is gradually reduced, and the thermosetting agent (E) is added, mixed and stirred, and judged visually. The concentration of the thermosetting agent (E) that is first judged to be dissolved is taken as the solubility.

In addition, the liquid crystal sealant is preferably heated at 25°C in an atmosphere at 120°C (constant temperature) while measuring the storage modulus (G') and loss modulus (G'') with a dynamic viscoelasticity measuring device (rheometer). When the liquid crystal sealant is placed in an atmosphere at 120°C (constant temperature) and heated, the time until G' and G'' match is preferably 450 seconds or less, more preferably 440 seconds or less, and even more preferably 430 seconds or less. The point at which G' and G'' match is also called the gel point, and is the point at which the overall behavior of the composition changes from liquid (G'' is dominant) to solid (G' is dominant). When the gel point is exceeded, G' rises rapidly and the composition hardens rapidly. For a certain composition, the shorter the time it takes to reach the gel point when heated, the easier it is for the composition to harden at the heating temperature.

In the present disclosure, the shorter the time it takes to reach the gel point when heated at a low temperature of 120°C, the better the low-temperature curing properties of the liquid crystal sealant. As described above, the hydrophobic heat curing agent used in the present disclosure suppresses the occurrence of bright spots (roughness), but on the other hand, since it has a high affinity with hydrophobic liquid crystal molecules during curing (heating), it is prone to seepage into the liquid crystal, as has been known in the past. In particular, when attempting to make the liquid crystal sealant curable at low temperatures in order to increase the selection of substrates, the liquid crystal sealant is often cured by heating at low temperatures for a long time. This long heating period suppresses excessive seepage of the heat curing agent, so it is preferable to make the liquid crystal sealant curable in a short time even at low temperatures.

Liquid crystal sealants that require a short time to reach the gel point can be prepared by various methods. For example, the time to reach the gel point can be shortened to the above range by selecting a thermosetting agent (E) as described below, using a multifunctional epoxy resin, or adding a thermal radical generator.

Moreover, the sealing agent preferably has a moisture permeability of less than 50 g/m ² in a cured product having a thickness of 0.6 mm under an environment of 60° C. and 90% Rh.

The above moisture permeability is specifically measured by the following method.

The sealant is applied to a release paper with a thickness of 300 μm using an applicator. The applied sealant is then placed in a nitrogen replacement container and purged with nitrogen for 5 minutes, after which it is irradiated with light of 3000 mJ/cm ² (light calibrated with a 365 nm wavelength sensor) and further heated at 120° C. for 1 hour to produce a cured film.

Two sheets of cured film are placed on an aluminum cup containing calcium chloride (anhydrous) as a moisture absorbent, and an aluminum ring is placed on top and screwed, and the initial weight of the entire aluminum cup is measured. The aluminum cup is then placed in a thermostatic chamber set at 60°C and 90% Rh, and after 24 hours, the aluminum cup is taken out and its weight is measured. The obtained weight value is substituted into the following formula to calculate the moisture permeability.
Formula:
Moisture permeability=(weight after test−weight before test)×film thickness/(film area×100)

Sealants with the above moisture permeability can be prepared in a variety of ways. For example, the above properties can be imparted to sealants by using flexible compounds with aromatic rings in the molecule or compounds that have a rounded structure as a stable structure.

An example of a sealant having the above characteristics will be described in more detail below. The sealant preferably contains a curable resin, a photopolymerization initiator or a heat curing agent that cures the curable resin, and other substances such as inorganic fillers.

The viscosity of the above sealant at 25°C and 2.5 rpm using an E-type viscometer is preferably 200 Pa·s or more and 450 Pa·s or less, and more preferably 300 Pa·s or more and 400 Pa·s or less. If the viscosity is within the above range, the sealant can be easily applied using a dispenser.

2-1-2. Combination of materials used in the first disclosure, etc. In the liquid crystal sealant according to the first disclosure, in addition to using a heat curing agent (E) having a solubility in water of 5 g/100 g or less at 20° C., the above-mentioned heat curing compound (A) having two or more epoxy groups in the molecule, specific curable compound (B), other curable compound (C), partial epoxy (meth)acrylate (D), photopolymerization initiator (F), inorganic filler (G), and other materials can be widely used. In this case, the type of resin may be appropriately selected so that the Young's modulus of the cured product measured at 23° C. is 0.5 GPa or more and less than 3.0 GPa.

The thermosetting compound (A) can adjust various physical properties of the liquid crystal sealant. For example, as described above, by using an epoxy resin containing silicone, an epoxy resin having polyethylene glycol or polypropylene glycol, an epoxy resin having a urethane bond, or an epoxy resin having a rubber structure as the thermosetting compound (A), the Young's modulus of the cured product can be reduced.

The content of the thermosetting compound (A) is preferably 3 parts by mass or more and 30 parts by mass or less when the total mass of the curable resin is 100 parts by mass. When the content of the thermosetting compound (A) is 3 parts by mass or more, the moisture permeability of the cured product can be further reduced, and the display characteristics of the obtained liquid crystal panel can be further improved. When the content of the thermosetting compound (A) is 30 parts by mass or less, the flexibility of the cured product can be more sufficiently increased (Young's modulus can be further sufficiently reduced) to increase the drop resistance. From the above viewpoint, the content of the thermosetting compound (A) is preferably 10 parts by mass or more and 30 parts by mass or less, and more preferably 10 parts by mass or more and 25 parts by mass or less.

The specific curable compound (B) makes the cured product of the liquid crystal sealant easier to expand and contract. This not only increases the resistance to impacts such as when the liquid crystal panel is dropped, but also makes it easier to suppress cracking of the cured product of the sealant when a liquid crystal display panel containing the cured product of the sealant is subjected to pressure treatment. In particular, when a curable compound represented by general formula (2) is used as the specific curable compound (B), the effect of making the cured product easier to expand and contract is remarkable.

The content of the specific curable compound (B) is preferably 40 parts by mass or more and 90 parts by mass or less when the total mass of the curable resin is 100 parts by mass. When the content of the specific curable compound (B) is 40 parts by mass or more, the flexibility can be more sufficiently increased (Young's modulus can be more sufficiently reduced), and the resistance to impact caused by dropping the liquid crystal panel can be more sufficiently increased, and cracking of the cured product of the sealant can be more suppressed when the liquid crystal display panel is subjected to pressure treatment. When the content of the specific curable compound (B) is 90 parts by mass or less, the humidity resistance of the cured product can be more sufficiently increased and the display characteristics of the liquid crystal panel can be more sufficiently improved. From the above viewpoint, the content of the specific curable compound (B) is preferably 50 parts by mass or more and 80 parts by mass or less.

The other curable compounds (C) can be used, for example, to impart photocurability to the liquid crystal sealant using a photocurable compound. In addition, the various physical properties of the liquid crystal sealant can be adjusted by selecting the other curable compounds (C).

The content of the other curable compound (C) is preferably an amount that is 0 parts by mass or more and less than 50 parts by mass, and more preferably an amount that is 5 parts by mass or more and 40 parts by mass or less, when the total mass of the curable resin is 100 parts by mass.

According to the new findings of the present inventors, a curable compound containing one (meth)acryloyl group in one molecule is likely to dissolve in liquid crystal and cause contamination of the liquid crystal. Therefore, from the viewpoint of suppressing contamination of the liquid crystal, the content of the curable compound containing one (meth)acryloyl group in one molecule is preferably an amount less than 10 parts by mass, more preferably an amount less than 5 parts by mass, even more preferably an amount less than 1 part by mass, and particularly preferably an amount less than 0.1 parts by mass, when the total mass of the curable resin is 100 parts by mass. The lower limit of the content of the curable compound containing one (meth)acryloyl group in one molecule can be 0 parts by mass.

Partial epoxy (meth)acrylate (D) can increase the adhesion of the cured sealant to the substrate.

In addition, the partial epoxy (meth)acrylate (D) can increase the adhesiveness of the cured product, but on the other hand, it is difficult to improve the flexibility of the cured product. Therefore, from the viewpoint of further increasing the flexibility of the cured product, it is preferable that the content of the partial epoxy (meth)acrylate (D) is smaller. From the above viewpoint, the content of the partial epoxy (meth)acrylate (D) is preferably an amount that is less than 10 parts by mass when the total mass of the curable resin is 100 parts by mass, more preferably an amount that is 5 parts by mass or less, even more preferably an amount that is 1 part by mass or less, and particularly preferably an amount that is 0.1 parts by mass or less. The lower limit of the above content of the partial epoxy (meth)acrylate (D) can be 0 parts by mass.

The heat curing agent (E) is a hydrophilic heat curing agent having a solubility in water at 20°C of 5 g/100 g or less. By having the solubility of the heat curing agent (E) be 5 g/100 g or less, it is possible to suppress the attraction of the heat curing agent by the moisture in the liquid crystal during heat curing, and to suppress the occurrence of bright spots (roughness). From the above viewpoint, the solubility is more preferably 3 g/100 g or less, and even more preferably less than 1 g/100 g. The lower limit of the solubility is not particularly limited, but can be 3 g/100 g or more.

The hydrophilic heat curing agent (E) is preferably an imidazole-based heat latent curing agent, an amine adduct-based heat latent curing agent, or a polyamine-based heat latent curing agent. These heat curing agents are less likely to seep into the liquid crystal, and are thought to be able to more effectively suppress the occurrence of bright spots (roughness). From the viewpoint of more effectively suppressing the occurrence of bright spots (roughness), the hydrophilic heat curing agent (E) is preferably a polyamine-based heat latent curing agent.

From the viewpoint of increasing the viscosity stability of the thermosetting resin composition and not impairing the moisture resistance of the cured product, the above-mentioned hydrophilic thermosetting agent (E) preferably has a melting point of 50°C or higher and 250°C or lower, more preferably a melting point of 70°C or higher and 150°C or lower, and even more preferably a melting point of 80°C or higher and 120°C or lower.

Examples of imidazole-based thermally latent curing agents include 2-phenylimidazole (melting point 137-147°C). Examples of commercially available imidazole-based thermally latent curing agents include 2P4MHZ-PW manufactured by Shikoku Chemical Industry Co., Ltd.

Amine adduct-based thermal latent curing agents are thermal latent curing agents consisting of an addition compound obtained by reacting an amine compound having catalytic activity with any compound. Examples of amine adduct-based thermal latent curing agents include AmiCure PN-40 (melting point 110°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure PN-50 (melting point 120°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure PN-23 (melting point 100°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure PN-31 (melting point 115°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure PN-H (melting point 115°C) manufactured by Ajinomoto Fine Techno Co., Ltd., AmiCure MY-24 (melting point 120°C) manufactured by Ajinomoto Fine Techno Co., Ltd., and AmiCure MY-H (melting point 131°C) 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 amine with epoxy. Examples include ADEKA HARDENER EH4339S (softening point 120-130°C) manufactured by ADEKA Corporation, and ADEKA HARDENER EH4357S (softening point 73-83°C) manufactured by ADEKA Corporation.

The content of the hydrophilic heat curing agent (E) is preferably 10 parts by mass or more and 200 parts by mass or less, more preferably 50 parts by mass or more and 160 parts by mass or less, and even more preferably 70 parts by mass or more and 120 parts by mass or less, when the total mass of the heat curing compound (A) is 100 parts by mass. When the content of the heat curing agent (E) is 10 parts by mass or more, it is easy to increase the curing property of the heat curing compound (A). When the content of the hydrophilic heat curing agent (E) is 200 parts by mass or less, it is easy to suppress the occurrence of bright spots (roughness) caused by the hydrophilic heat curing agent (E) seeping into the liquid crystal.

The photopolymerization initiator (F) can initiate the curing (polymerization) of photocurable components such as a specific curable compound (B), other curable compounds (C), partial epoxy (meth)acrylate (D), etc.

The content of the photopolymerization initiator (F) is preferably an amount of 0.01 parts by mass or more and 10 parts by mass or less when the total mass of the photocurable compound (for example, the above-mentioned partial epoxy (meth)acrylate (D), the specific curable compound (B), and the other curable compounds (C) is 100 parts by mass. When the content of the photopolymerization initiator (F) is 0.01 parts by mass or more, the curability of the sealant is easily improved. When the content of the photopolymerization initiator (F) is 10 parts by mass or less, contamination of the liquid crystal due to the photopolymerization initiator (F) dissolving into the liquid crystal is more easily suppressed. The content of the photopolymerization initiator (F) is more preferably 0.1 parts by mass or more and 5 parts by mass or less, even more preferably 0.1 parts by mass or more and 3 parts by mass or less, and particularly preferably 0.1 parts by mass or more and 2.5 parts by mass or less.

The inorganic filler (G) not only imparts a predetermined hardness and linear expansion to the cured product, but also inhibits the penetration of moisture and other substances through the inside of the cured product, thereby further reducing the moisture permeability of the cured product.

The content of the inorganic filler (G) is preferably 10 parts by mass or more and 60 parts by mass or less, more preferably 20 parts by mass or more and 55 parts by mass or less, even more preferably 20 parts by mass or more and 50 parts by mass or less, and particularly preferably 20 parts by mass or more and 30 parts by mass or less, when the total mass of the curable resin is 100 parts by mass. The higher the content of the inorganic filler (G), the lower the moisture permeability of the cured product. On the other hand, by not increasing the content of the inorganic filler (G) too much, the resistance to impacts such as dropping the liquid crystal display panel can be sufficiently guaranteed, and leakage of the sealant can be suppressed, thereby improving the applicability. From the viewpoint of balancing these, it is preferable that the content of the inorganic filler (G) is within the above range.

The liquid crystal sealant in the present disclosure may contain the above-mentioned thermal radical generator, organic fine particles, coupling agents such as silane coupling agents, ion trapping agents, ion exchange agents, leveling agents, pigments, dyes, sensitizers, plasticizers, and defoamers.

The content of the thermal radical polymerization initiator is preferably 0.01 parts by mass or more and 5.0 parts by mass or less when the total mass of the sealant is 100 parts by mass. By making the content of the thermal radical polymerization initiator 0.01 parts by mass or more, the thermal curing property of the sealant can be further improved. By making the content of the thermal radical polymerization initiator 5.0 parts by mass or more, the dispensing stability of the sealant can be further improved.

The content of the organic fine particles is preferably 5 parts by mass or more and 17 parts by mass or less when the total mass of the sealant is 100 parts by weight. When the content of the organic fine particles is 5 parts by mass or more, the adhesive strength between the cured product and the substrate can be further increased. On the other hand, when the content of the organic fine particles is 17 parts by mass or less, the amount of other components (e.g., curable resin) becomes sufficiently large, and the strength of the cured product can be further increased.

The content of the silane coupling agent is preferably 0.01 parts by mass or more and 5 parts by mass or less when the total mass of the sealant is 100 parts by weight. When the content of the silane coupling agent is 0.01 parts by mass or more, the adhesive strength between the cured product and the substrate can be further increased.

The total amount of the other components is preferably 0.1 parts by mass or more and 50 parts by mass or less when the total mass of the sealant is 100 parts by mass. When the total amount of the other components is 50 parts by mass or less, the viscosity of the sealant is unlikely to increase excessively, and the coating stability of the sealant is unlikely to be impaired.

2-1-3. Summary of the First Disclosure According to the above-mentioned first disclosure, for example, the following liquid crystal sealant is provided.

[1] The Young's modulus of the cured product measured at 23° C. is 0.5 GPa or more and less than 3.0 GPa;
A thermosetting compound (A) having an epoxy group in the molecule;
and a heat curing agent (E), the heat curing agent (E) having a solubility in water at 20°C of 5 g/100 g or less.
Liquid crystal sealant.

[2] The heat curing agent (E) is at least one heat curing agent 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 liquid crystal sealant according to [1].

[3] A liquid crystal sealant according to [1] or [2], in which when the liquid crystal sealant is heated at 25°C to 120°C while measuring the storage modulus (G') and loss modulus (G'') using a dynamic viscoelasticity measuring device (rheometer), the time until G' and G'' become equal is 450 seconds or less.

[4] A liquid crystal sealant according to any one of [1] to [3], comprising a curable compound (B) having a characteristic ratio of 4.70 or less, a Tg of 250°C or more and 340°C or less, and a weight average molecular weight (Mw) of 1,000 or more.

・・・一般式（２）
（一般式（２）中、Ｒ_１は多価エポキシ化合物に由来する２価の残基を示し、Ｒ_２は独立して環状ラクトンを開環させて得られる２価の構造を示し、Ｒ_３は独立して炭素数１以上６以下の直鎖状または分岐鎖を有するアルキレン基を示し、Ｒ_４は独立して水素原子またはメチル基を示す。） [5] The liquid crystal sealant according to [4], wherein the curable compound (B) is a compound represented by general formula (2).

...General formula (2)
(In general formula (2), _R1 represents a divalent residue derived from a polyepoxy compound, _R2 independently represents a divalent structure obtained by ring-opening a cyclic lactone, _R3 independently represents a linear or branched alkylene group having 1 to 6 carbon atoms, and _R4 independently represents a hydrogen atom or a methyl group.)

[6] A liquid crystal sealant according to [4] or [5], in which the content of the curable compound (B) per 100 parts by mass of the curable resin is 40 parts by mass or more and 90 parts by mass or less.

[7] Having a curable resin and an inorganic filler (G),
The content of the inorganic filler (G) relative to 100 parts by mass of the curable resin is 20 parts by mass or more and 55 parts by mass or less.
The liquid crystal sealant according to any one of [1] to [6].

[8] The liquid crystal sealant according to any one of [1] to [7], wherein the moisture permeability of a 0.6 mm-thick cured product in an environment of 60°C and 90% Rh is less than 50 g/ ^m2 .

2-2. Second Disclosure 2-2-1 Problems Related to the Second Disclosure As described in Patent Documents 1 to 5, various researches have been conducted on sealants with improved flexibility after curing in order to improve resistance to impacts such as dropping. Depending on the type of liquid crystal display panel, the sealant is required to have even higher flexibility so that it can accommodate bending with a smaller curvature. On the other hand, according to the new findings of the present inventors, increasing the flexibility (elongation) of the sealant after curing may increase moisture permeability, which may reduce the long-term reliability of the liquid crystal.

The second disclosure of this specification has been made in consideration of the above-mentioned problems, and aims to provide a liquid crystal sealant having high flexibility and low moisture permeability when cured, a method for manufacturing a liquid crystal display panel using said liquid crystal sealant, and a liquid crystal display panel manufactured using said liquid crystal sealant.

2-2-2. Description of Liquid Crystal Sealant The second disclosure in this specification relates to a liquid crystal sealant having high flexibility and low moisture permeability when cured.

The above-mentioned sealing agent has an elongation of 30% or more when measured at 23°C in a cured product, and a moisture permeability of a 0.6 mm-thick cured product in an environment of 60°C and 90Rh is less than 50 g/ ^m2 .

The above elongation rate is specifically measured by the following method.

The sealant is applied to a release paper with a thickness of 100 μm using an applicator. The applied sealant is then placed in a nitrogen replacement container and purged with nitrogen for 5 minutes, after which it is irradiated with light of 3000 mJ/cm ² (light calibrated with a 365 nm wavelength sensor) and further heated at 120° C. for 1 hour to produce a cured film.

The obtained cured film was cut into strips (length 150 mm, width 10 mm) and then subjected to a tensile test at room temperature (23°C) at a test speed of 10 mm/min using an autograph tensile testing machine (Shimadzu Corporation, AG-X). The elongation was calculated from the distance at which the stress had decreased by 80% or more from the yield point.

The above moisture permeability is specifically the elongation measured by the following method.

The sealant is applied to a release paper with a thickness of 300 μm using an applicator. The applied sealant is then placed in a nitrogen replacement container and purged with nitrogen for 5 minutes, after which it is irradiated with light of 3000 mJ/cm ² (light calibrated with a 365 nm wavelength sensor) and further heated at 120° C. for 1 hour to produce a cured film.

Two sheets of cured film are placed on an aluminum cup containing calcium chloride (anhydrous) as a moisture absorbent, and an aluminum ring is placed on top and screwed, and the initial weight of the entire aluminum cup is measured. The aluminum cup is then placed in a thermostatic chamber set at 60°C and 90% Rh, and after 24 hours, the aluminum cup is taken out and its weight is measured. The obtained weight value is substituted into the following formula to calculate the moisture permeability.
Formula:
Moisture permeability=(weight after test−weight before test)×film thickness/(film area×100)

A sealant having the above-mentioned properties can be prepared in various ways. For example, the above-mentioned properties can be imparted to the sealant by using a flexible compound having an aromatic ring in the molecule or by using the specific curable compound (B) described above.

2-2-3. Combination of materials used in the second disclosure, etc. The liquid crystal sealant according to the second disclosure can be made from a wide variety of materials, including the above-mentioned thermosetting compound (A) having two or more epoxy groups in the molecule, the specific curable compound (B), other curable compounds (C), partial epoxy (meth)acrylate (D), heat curing agent (E), photopolymerization initiator (F), inorganic filler (G), and other materials. In this case, the type of resin may be appropriately selected so that the elongation of the cured product measured at 23°C is 30% or more, and the moisture permeability of the cured product having a thickness of 0.6 mm under a 60°C, 90Rh environment is less than 50 g/ ^m2 .

The thermosetting compound (A) can adjust various physical properties of the liquid crystal sealant.

The content of the thermosetting compound (A) is preferably 3 parts by mass or more and 30 parts by mass or less when the total mass of the curable resin is 100 parts by mass. When the content of the thermosetting compound (A) is 3 parts by mass or more, the moisture permeability of the cured product can be further reduced and the display characteristics of the obtained liquid crystal panel can be improved. When the content of the thermosetting compound (A) is 30 parts by mass or less, the elongation and flexibility of the cured product can be more sufficiently improved. From the above viewpoint, the content of the thermosetting compound (A) is preferably 10 parts by mass or more and 30 parts by mass or less, and more preferably 10 parts by mass or more and 25 parts by mass or less.

The specific curable compound (B) has molecules that can take on a curled or stretched state depending on the expansion and contraction of the sealant, making it easier for the sealant to expand and contract, increasing the extensibility of the cured product, and increasing the flexibility of the cured product, making it less likely to peel or deform even when the substrate is bent to a smaller curvature. In particular, when a curable compound represented by general formula (2) is used as the specific curable compound (B), the effect of making the cured product more easily expand and contract is remarkable.

The content of the specific curable compound (B) is preferably 40 parts by mass or more and 90 parts by mass or less when the total mass of the curable resin is 100 parts by mass. When the content of the specific curable compound (B) is 40 parts by mass or more, the elongation and flexibility of the cured product can be more sufficiently improved. When the content of the specific curable compound (B) is 90 parts by mass or less, the humidity resistance of the cured product can be further improved and the display characteristics of the liquid crystal panel can be further improved. From the above viewpoint, the content of the specific curable compound (B) is more preferably 50 parts by mass or more and 80 parts by mass or less.

The other curable compounds (C) can be used, for example, to impart photocurability to the liquid crystal sealant using a photocurable compound. In addition, the various physical properties of the liquid crystal sealant can be adjusted by selecting the other curable compounds (C).

The content of the other curable compound (C) is preferably an amount that is 0 parts by mass or more and less than 50 parts by mass, and more preferably an amount that is 5 parts by mass or more and 40 parts by mass or less, when the total mass of the curable resin is 100 parts by mass.

According to the new findings of the present inventors, a curable compound containing one (meth)acryloyl group in one molecule is likely to dissolve in liquid crystal and cause contamination of the liquid crystal. Therefore, from the viewpoint of suppressing contamination of the liquid crystal, the content of the curable compound containing one (meth)acryloyl group in one molecule is preferably an amount less than 10 parts by mass, more preferably an amount less than 5 parts by mass, even more preferably an amount less than 1 part by mass, and particularly preferably an amount less than 0.1 parts by mass, when the total mass of the curable resin is 100 parts by mass. The lower limit of the content of the curable compound containing one (meth)acryloyl group in one molecule can be 0 parts by mass.

Partial epoxy (meth)acrylate (D) can increase the adhesion of the cured sealant to the substrate.

In addition, the partial epoxy (meth)acrylate (D) can increase the adhesiveness of the cured product, but on the other hand, it is difficult to improve the flexibility of the cured product. Therefore, from the viewpoint of further increasing the flexibility of the cured product, it is preferable that the content of the partial epoxy (meth)acrylate (D) is smaller. From the above viewpoint, the content of the partial epoxy (meth)acrylate (D) is preferably an amount that is less than 10 parts by mass when the total mass of the curable resin is 100 parts by mass, more preferably an amount that is 5 parts by mass or less, even more preferably an amount that is 1 part by mass or less, and particularly preferably an amount that is 0.1 parts by mass or less. The lower limit of the above content of the partial epoxy (meth)acrylate (D) can be 0 parts by mass.

The thermosetting agent (E) can cure thermosetting components such as the thermosetting compound (A), other curable compounds (C), and partial epoxy (meth)acrylate (D).

The content of the heat curing agent (E) is preferably 3 parts by mass or more and 75 parts by mass or less, more preferably 3 parts by mass or more and 50 parts by mass or less, and even more preferably 5 parts by mass or more and 40 parts by mass or less, when the total mass of the heat curing compound (A) is 100 parts by mass. When the content of the heat curing agent (E) is 3 parts by mass or more, it is easy to increase the curing property of the heat curing compound (A). When the content of the heat curing agent (E) is 75 parts by mass or less, it is easy to suppress contamination of the liquid crystal due to the heat curing agent (E) dissolving into the liquid crystal.

In this disclosure, too, it is the same as the first disclosure that the occurrence of bright spots (roughness) due to pressure treatment on a substrate can be suppressed by using a hydrophobic heat curing agent that satisfies the condition that the solubility in water at 20°C is 5 g/100 g or less. Also, from the viewpoint of suppressing the seepage of the heat curing agent (E) into the liquid crystal during heat curing, it is preferable that the time until G' and G'' match when the above liquid crystal sealant 25 is heated at 120°C is 450 seconds or less, more preferably 440 seconds or less, and even more preferably 430 seconds or less. As in the first disclosure.

The photopolymerization initiator (F) can initiate the curing (polymerization) of photocurable components such as a specific curable compound (B), other curable compounds (C), partial epoxy (meth)acrylate (D), etc.

The amount of photopolymerization initiator (F) is preferably 0.01 parts by mass or more and 10 parts by mass or less when the total mass of the photocurable compound (for example, the above-mentioned partial epoxy (meth)acrylate (D), the specific curable compound (B), and the other curable compounds (C) is 100 parts by mass. When the content of photopolymerization initiator (F) is 0.01 parts by mass or more, the curability of the sealant is easily improved. When the content of photopolymerization initiator (F) is 10 parts by mass or less, contamination of the liquid crystal due to the photopolymerization initiator (F) dissolving into the liquid crystal is more easily suppressed. The content of photopolymerization initiator (F) is more preferably 0.1 parts by mass or more and 5 parts by mass or less, even more preferably 0.1 parts by mass or more and 3 parts by mass or less, and particularly preferably 0.1 parts by mass or more and 2.5 parts by mass or less.

The inorganic filler (G) not only imparts a predetermined hardness and linear expansion to the cured product, but also inhibits the penetration of moisture and other substances through the inside of the cured product, thereby further reducing the moisture permeability of the cured product.

The content of the inorganic filler (G) is preferably 30 parts by mass or more and 500 parts by mass or less, more preferably 50 parts by mass or more and 250 parts by mass or less, even more preferably 70 parts by mass or more and 200 parts by mass or less, and particularly preferably 100 parts by mass or more and 200 parts by mass or less, when the total mass of the curable resin is 100 parts by mass. The higher the content of the inorganic filler (G), the lower the moisture permeability of the cured product. On the other hand, by not making the content of the inorganic filler (G) too high, the elongation and flexibility of the cured product can be more fully ensured. From the viewpoint of balancing these, it is preferable that the content of the inorganic filler (G) is within the above range.

The liquid crystal sealant in the present disclosure may contain the above-mentioned thermal radical generator, organic fine particles, coupling agents such as silane coupling agents, ion trapping agents, ion exchange agents, leveling agents, pigments, dyes, sensitizers, plasticizers, and defoamers.

The content of the thermal radical polymerization initiator is preferably 0.01 parts by mass or more and 5.0 parts by mass or less when the total mass of the sealant is 100 parts by mass. By making the content of the thermal radical polymerization initiator 0.01 parts by mass or more, the thermal curing property of the sealant can be further improved. By making the content of the thermal radical polymerization initiator 5.0 parts by mass or more, the dispensing stability of the sealant can be further improved.

The content of the organic fine particles is preferably 5 parts by mass or more and 17 parts by mass or less when the total mass of the sealant is 100 parts by weight. When the content of the organic fine particles is 5 parts by mass or more, the adhesive strength between the cured product and the substrate can be further increased. On the other hand, when the content of the organic fine particles is 17 parts by mass or less, the amount of other components (e.g., curable resin) becomes sufficiently large, and the strength of the cured product can be further increased.

The content of the silane coupling agent is preferably 0.01 parts by mass or more and 5 parts by mass or less when the total mass of the sealant is 100 parts by weight. When the content of the silane coupling agent is 0.01 parts by mass or more, the adhesive strength between the cured product and the substrate can be further increased.

The total amount of the other components is preferably 0.1 parts by mass or more and 50 parts by mass or less when the total mass of the sealant is 100 parts by mass. When the total amount of the other components is 50 parts by mass or less, the viscosity of the sealant is unlikely to increase excessively, and the coating stability of the sealant is unlikely to be impaired.

2-2-4. Summary of the Second Disclosure According to the above-mentioned second disclosure, for example, the following liquid crystal sealant is provided.

[1] The elongation of the cured product measured at 23°C is 30% or more, and
The moisture permeability of the cured product having a thickness of 0.6 mm in an environment of 60°C and 90Rh is less than 50g/ ^m2 .
Liquid crystal sealant.

[2] Contains a curable resin,
The liquid crystal sealant according to [1], wherein the content of the partial epoxy (meth)acrylate (A) is 10 parts by mass or less relative to 100 parts by mass of the curable resin.

[3] A liquid crystal sealant according to [1] or [2], which contains a curable compound (B) having a characteristic ratio of 4.70 or less, a Tg of 250°C or more and 340°C or less, and a weight average molecular weight (Mw) of 1,000 or more.

・・・一般式（１）
（一般式（１）中、Ｒ_１は多価エポキシ化合物に由来する２価の残基を示し、Ｒ_２は独立して環状ラクトンを開環させて得られる２価の構造を示し、Ｒ_３は独立して炭素数１以上６以下の直鎖状または分岐鎖を有するアルキレン基を示し、Ｒ_４は独立して水素原子またはメチル基を示す。） [4] The liquid crystal sealant according to [3], wherein the curable compound (B) is a compound represented by general formula (2).

...General formula (1)
(In general formula (1), _R1 represents a divalent residue derived from a polyfunctional epoxy compound, _R2 independently represents a divalent structure obtained by ring-opening a cyclic lactone, _R3 independently represents a linear or branched alkylene group having 1 to 6 carbon atoms, and _R4 independently represents a hydrogen atom or a methyl group.)

[5] Contains a curable resin,
The liquid crystal sealant according to [4], wherein the content of the curable compound (B) represented by the general formula (1) is 40 parts by mass or more and 90 parts by mass or less relative to 100 parts by mass of the curable resin.

[6] A liquid crystal sealant according to any one of [1] to [5], comprising a thermosetting compound (excluding partial epoxy (meth)acrylate) having an epoxy group in its molecule (A) and a thermosetting agent (E).

[7] The liquid crystal sealant described in [6], wherein the heat curing agent (E) is at least one heat curing agent selected from the group consisting of dihydrazide-based heat latent curing agents, imidazole-based heat latent curing agents, amine adduct-based heat latent curing agents, and polyamine-based heat latent curing agents.

[8] The liquid crystal sealant described in [6] or [7], wherein the thermosetting compound (A) is a thermosetting compound having a bisphenol F skeleton in the molecule.

[9] A curable resin and an inorganic filler (G),
The liquid crystal sealant according to any one of [1] to [8], wherein the content of the inorganic filler (G) relative to 100 parts by mass of the curable resin is 50 parts by mass or more and 250 parts by mass or less.

3. Liquid crystal display panel and its manufacturing method Another embodiment of the present invention relates to a liquid crystal display panel including a pair of substrates (a display substrate and an opposing substrate) each having an alignment film, a frame-shaped seal member disposed between the alignment films of the pair of substrates, and a liquid crystal layer filled in the space surrounded by the seal member between the pair of substrates. In the liquid crystal display panel, the seal member is a cured product of the sealant (liquid crystal sealant) disclosed in each of the above disclosures.

The display substrate and the counter substrate are both transparent substrates. The material of the transparent substrate may be an inorganic material such as glass, or a plastic such as polycarbonate, polyethylene terephthalate, polyethersulfone, or PMMA.

A matrix-shaped TFT, a color filter, a black matrix, etc. may be arranged on the surface of the display substrate or the counter substrate. An alignment film is further arranged on the surface of the display substrate or the counter substrate. The alignment film contains a known organic alignment agent or an inorganic alignment agent.

The liquid crystal display panel is manufactured using the liquid crystal sealant of the present invention. There are generally two methods for manufacturing liquid crystal display panels: the liquid crystal dropping method and the liquid crystal injection method. It is preferable that the liquid crystal display panel of the present invention is 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) a step of applying the above-mentioned liquid crystal sealant onto an alignment film of one of a pair of substrates each having an alignment film to form a seal pattern;
2) dropping liquid crystal onto one of the substrates in an area surrounded by the seal pattern or onto the other substrate while the seal pattern is in an uncured state;
3) overlapping one substrate and the other substrate via a seal pattern;
4) curing the seal pattern.

In step 2), the seal pattern is in an uncured state, which means that the curing reaction of the liquid crystal sealant has not progressed to the gel point. Therefore, in step 2, the seal pattern may be semi-cured by irradiating it with light or heating it in order to suppress dissolution of the liquid crystal sealant into the liquid crystal. One substrate and the other substrate are a display substrate or an opposing substrate, respectively.

In step 4), curing by light irradiation and then curing by heating may be performed. Curing by light irradiation allows the liquid crystal sealant to be cured in a short time, thereby suppressing dissolution into the liquid crystal. Combining curing by light irradiation and curing by heating can reduce damage to the liquid crystal layer caused by light compared to curing by light irradiation alone.

The light to be irradiated is selected appropriately depending on the type of photopolymerization initiator (F) in the above-mentioned sealant, but light in the visible light region is preferred, for example light with a wavelength of 370 nm or more and 450 nm or less. This is because light with the above wavelengths causes relatively little damage to the liquid crystal material and the 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 specific curable compound (B). The light curing 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 sealant, but is, for example, 120°C, and the heat curing time is about 2 hours, but when the low temperature curing property is enhanced, for example as in the first disclosure, the heat curing time can be about 50 minutes to 1.5 hours.

After step 4), the method may include step 5) of subjecting the substrate to a pressure treatment. The pressure treatment may be, for example, a process of thinning the substrate by polishing. The conditions for the pressure treatment are not particularly limited, but may be, for example, 5 sets of 7 minutes at a load of 80 N.

The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[Materials used in the examples]
1. Synthesis of specific curable compound (B) <Synthesis Example 1: Curable compound (B-1)>
(BisA type acrylic resin)
116 g of hydroxyethyl acrylate, 0.2 g of p-methoxyphenol as a polymerization inhibitor, 148 g of phthalic anhydride, and 342 g of ε-caprolactone were charged into a reaction flask, and dry air was fed into the flask to react for 6 hours while stirring under reflux at 90° C. Then, 170 g of bisphenol A diglycidyl ether was added, and the mixture was reacted for 6 hours while stirring under reflux at 90° C. The obtained compound was washed 20 times with ultrapure water to obtain a curable compound B-1.

<Synthesis Example 2: Curable compound (B-2)>
(BisA type methacrylic resin)
130 g of hydroxyethyl methacrylate, 0.2 g of p-methoxyphenol as a polymerization inhibitor, 148 g of phthalic anhydride, and 342 g of ε-caprolactone were charged into a reaction flask, and the mixture was reacted for 6 hours at 90° C. while refluxing and stirring with dry air being fed in. Subsequently, 170 g of bisphenol A diglycidyl ether was added, and the mixture was reacted for 6 hours while stirring under reflux at 90° C. The resulting compound was washed 20 times with ultrapure water to obtain Curable Compound B-2. obtained.

<Synthesis Example 3: Curable compound (B-3)>
(BisF type acrylic resin)
116 g of hydroxyethyl acrylate, 0.2 g of p-methoxyphenol as a polymerization inhibitor, 148 g of phthalic anhydride, and 342 g of ε-caprolactone were charged into a reaction flask, and the mixture was reacted for 6 hours at 90° C. with reflux and stirring while blowing in dry air. Subsequently, 156 g of bisphenol F diglycidyl ether was added, and the mixture was reacted for 6 hours while stirring under reflux at 90° C. The resulting compound was washed 20 times with ultrapure water to obtain Curable Compound B-3. obtained.

<Synthesis Example 4: Curable compound (B-4)>
(BisF type methacrylic resin)
130 g of hydroxyethyl methacrylate, 0.2 g of p-methoxyphenol as a polymerization inhibitor, 148 g of phthalic anhydride, and 342 g of ε-caprolactone were charged into a reaction flask, and the mixture was reacted for 6 hours at 90° C. while refluxing and stirring with dry air being fed in. Subsequently, 156 g of bisphenol F diglycidyl ether was added, and the mixture was reacted for 6 hours while stirring under reflux at 90° C. The resulting compound was washed 20 times with ultrapure water to obtain Curable Compound B-4. obtained.

2. Preparation of other materials The following materials were used as other materials.

2-1. Curable resin 2-1-1. Thermosetting compound (A) having an epoxy group in the molecule
Thermosetting compound (A-1): Propylene oxide modified bisphenol A type epoxy resin (ADEKA CORPORATION, ADEKA RESIN EP-4000S ("ADEKA RESIN" and "ADEKA RESIN EP" are registered trademarks of the company))
Thermosetting compound (A-2): Bisphenol F type epoxy resin (manufactured by ADEKA Corporation, ADEKA RESIN EP-4901
Thermosetting compound (A-3): Rubber-modified (EPR-modified) bisphenol F type epoxy resin (ADEKA Corporation, ADEKA RESIN EPR-4030)

2-1-2. Other curable compounds (C)
Other curable compounds (C-1): Bisphenol A type epoxy acrylate (manufactured by Daicel Allnex Corporation, EBECRYL 3700 ("EBECRYL" is a registered trademark of the company))
Curable compound (C-2): 2-hydroxybutyl methacrylate (Light Ester HOB, manufactured by Kyoeisha Chemical Co., Ltd.)

2-1-3. Partial epoxy (meth)acrylate (D)
- KRM8287 manufactured by Daicel Allnex Corporation ("KRM" is a registered trademark of the company)

2-2. Heat curing agent 2-2-1. Heat curing agent (E)
Heat curing agent (E-1): Polyamine-based heat latent curing agent (manufactured by ADEKA Corporation, EH-4357S (solubility: less than 1 g/100 g))
Heat curing agent (E-2): Imidazole-based heat latent curing agent (manufactured by ADEKA Corporation, EH-4344S (solubility: 1 g/100 g or more and 5 g/100 g or less))
Heat curing agent (E-3): Dihydrazide-based heat latent curing agent (manufactured by Japan Finechem Co., Ltd., adipic acid dihydrazide (ADH) (solubility: 9 g/100 g))
Heat curing agent (E-4): Dihydrazide-based heat latent curing agent (manufactured by Japan Finechem Co., Ltd., malonic acid dihydrazide (MDH) (solubility 10 g/100 g))
Heat curing agent (E-5): Amine adduct-based heat latent curing agent (Amicure PN-50, manufactured by Ajinomoto Fine-Techno Co., Ltd. (Amicure is a registered trademark of Ajinomoto Co., Ltd.))
Heat curing agent (E-6): Dihydrazide-based heat latent curing agent (Amicure VDH, manufactured by Ajinomoto Fine-Techno Co., Ltd.)

The solubility of the heat curing agents (E-1) to (E-4) was measured by the method shown below.

(Method of measuring solubility)
(Measurement method)
100g of water and a given amount of curing agent were put into a 300mL beaker, mixed and stirred for 2 hours, and the state where it became transparent by visual observation was judged as dissolution. The amount of the thermosetting agent (E) added to the water was gradually reduced, and the thermosetting agent (E) was added, mixed and stirred, and visually judged. The concentration of the thermosetting agent (E) that was first judged as dissolved was taken as the solubility.

2-3. Photopolymerization initiator (F)
Photopolymerization initiator (F-1): OXE-02, manufactured by BASF
Photopolymerization initiator (F-2): Omnipol-TX manufactured by IGM ("Omnipol" is a registered trademark of the company)

2-4. Inorganic filler (G)
Silica particles: SO-C1, manufactured by Admatechs Co., Ltd.

2-5. Other materials Thermal radical generator (1): Water-soluble azo polymerization initiator (V-501, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Thermal radical generator (2): Water-soluble azo polymerization initiator (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., VA-086)
Fine particle polymer: Polymethacrylate-based organic fine particles (Zefiac F351, manufactured by Aica Kogyo Co., Ltd. ("Zefiac" is a registered trademark of Zeon Corporation))
Silane coupling agent: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.

2-6. Physical Properties of Each Material The weight average molecular weight (Mw) of each of the above-mentioned resin components was determined by gel permeation chromatography (GPC).

In addition, the epoxy equivalent of the resin component having epoxy groups was determined in accordance with JIS K7236 (2001).

In addition, the characteristic ratios and glass transition temperatures (Tg) of each of the above-mentioned resin components were determined by the Bicerano method using the calculation software Materials Studio 2020 Synthia.

The above physical properties are shown in Table 1.

[Examples and Comparative Examples Related to the First Disclosure]
1-1. Preparation of Sealing Agent 80 parts by mass of thermosetting compound (A-1), 520 parts by mass of curing compound (B-1), 60 parts by mass of other curing compound (C-1), 80 parts by mass of heat curing agent (E-1), 5 parts by mass of photopolymerization initiator (F-1), 175 parts by mass of silica particles, 70 parts by mass of fine particle polymer, and 10 parts by mass of silane coupling agent were thoroughly mixed using a triple roll to obtain a uniform liquid, thereby obtaining sealing agent (1).

Sealant (2) to sealant (14) were obtained in the same manner, except that the types and amounts of materials used were changed as shown in Tables 2 to 4.

The compositions of sealing agents (1) to (14) are shown in Tables 2 to 4. The numerical values given for each component indicate parts by weight unless otherwise specified.

1-2. Evaluation The prepared sealants (1) to (14) were evaluated for Young's modulus, breaking elongation, drop characteristics, moisture permeability, display characteristics, low-temperature curing properties, and coatability by the following methods.

<Young's Modulus>
The obtained sealant was applied to a release paper with a thickness of 100 μm using an applicator. The applied sealant was then placed in a nitrogen replacement container and purged with nitrogen for 5 minutes, after which it was irradiated with light of 3000 mJ/cm ² (light calibrated with a 365 nm wavelength sensor) and further heated at 120° C. for 1 hour to produce a cured film.

The obtained cured film was cut into strips (length 150 mm, width 10 mm) and then subjected to a tensile test at room temperature (23°C) at a test speed of 10 mm/min using an autograph tensile tester (Shimadzu Corporation, AG-X). Young's modulus was calculated from the slope of the stress and strain in the elastic region.

<Drop characteristics>
The obtained sealing agent was used with a dispenser (Shot Master, manufactured by Musashi Engineering) to form a 135 mm x 65 mm square seal pattern (cross-sectional area ³⁵⁰⁰ μm2) as a main seal on a 140 mm x 70 mm glass substrate (RT-DM88-PIN, manufactured by EHC) on which a transparent electrode and an alignment film had been previously formed.

Next, a liquid crystal material (MLC-6609-000, Merck) equivalent to the amount of the panel contents after lamination was precisely dropped into the frame of the main seal using a dispenser. After that, the pair of glass substrates were laminated under reduced pressure, and then exposed to the atmosphere to be laminated. Then, the two laminated glass substrates were held in a light-shielding box for one minute, and then irradiated with light containing 3000 mJ/ ^cm2 visible light (light with a wavelength of 370 to 450 nm) with only the liquid crystal portion masked with a substrate coated with a black matrix, and further heated at 120°C for one hour to harden the main seal and obtain a liquid crystal display panel.

The obtained liquid crystal display panel was dropped from 50 mm, and if there was no liquid crystal leakage due to peeling or cracking of the cell, a drop test was performed in which the cell was dropped from a position increased by 50 mm at a time, with the upper limit of the height being 500 mm. After the test, the cell was visually observed and the drop characteristics were evaluated according to the following criteria.
◎ No liquid crystal leakage due to peeling or cracking of the cell was confirmed up to 500 mm. ○ Liquid crystal leakage was confirmed in the liquid crystal display panel at a height of 300 mm or more and less than 500 mm. × Liquid crystal leakage was confirmed in the liquid crystal display panel at a height of less than 300 mm.

<Moisture permeability>
The obtained sealant was applied to a release paper with a thickness of 300 μm using an applicator. The applied sealant was then placed in a nitrogen replacement container and purged with nitrogen for 5 minutes, after which it was irradiated with light of 3000 mJ/cm ² (light calibrated with a 365 nm wavelength sensor) and further heated at 120° C. for 1 hour to produce a cured film.

Two sheets of cured film were placed on an aluminum cup containing calcium chloride (anhydrous) as a moisture absorbent, and an aluminum ring was placed on top and screwed, after which the initial weight of the entire aluminum cup was measured. The aluminum cup was then placed in a thermostatic chamber set at 60°C and 90% Rh, and after 24 hours had passed, the aluminum cup was taken out and its weight was measured. The obtained weight value was substituted into the following formula to calculate the moisture permeability.
Formula:
Moisture permeability=(weight after test−weight before test)×film thickness/(film area×100)

<Display characteristics (reduction of roughness)>
The obtained sealant was applied using a dispenser (Shot Master, manufactured by Musashi Engineering Co., Ltd.) to a 40 mm x 45 mm glass substrate (RT-DM88-PIN, manufactured by EHC Corporation) on which a transparent electrode and a coating film had been formed, to form a 35 mm x 35 mm square seal pattern (cross-sectional area ^3,500 μm2) as a main seal, and a 38 mm x 38 mm square seal pattern around the outer periphery.

Next, a liquid crystal material (MLC-7026-100, manufactured by Merck) in an amount equivalent to the liquid crystal content of the liquid crystal display panel to be obtained was precisely dropped into the frame of the main seal using a dispenser, and then left to stand for 100 minutes or 10 minutes. Then, the above glass substrate and a glass substrate paired with the above glass substrate were bonded together under a reduced pressure of 4 Pa, and then released to atmospheric pressure. After the two bonded glass substrates were held in a light-shielding box for one minute, the main seal was masked with a square black matrix of 36 mm x 36 mm by a hand-held substrate, and in this state, light with a wavelength of 370 to 450 nm was irradiated to the glass substrate at 1 J/cm ^2. These glass substrates were further heated at 120°C for one hour to harden the main seal and obtain a liquid crystal cell. Then, polarizing films were attached to both sides of the obtained liquid crystal cell to obtain a liquid crystal display panel. The obtained liquid crystal display panel was subjected to a pressure treatment at 80 N for 10 minutes.

The display characteristics of the obtained liquid crystal panel were evaluated according to the following criteria.
⊚: No bright spots (roughness) were observed in either the sample left to stand for 100 minutes or for 10 minutes.
○ Bright spots (roughness) were observed in the sample left to stand for 100 minutes, but no bright spots (roughness) were observed in the sample left to stand for 10 minutes.
x: Bright spots (roughness) were observed in both the sample left to stand for 100 minutes and the sample left to stand for 10 minutes.

<Low temperature curing>
The sealant at 25°C was placed in a constant temperature atmosphere of 120°C and heated while measuring the storage modulus (G') and loss modulus (G'') with a dynamic viscoelasticity measuring device (rheometer). The time from the start of heating until G' and G'' became equal was measured.

The results of evaluation of the Young's modulus, drop characteristics, moisture permeability, display characteristics, and coatability of sealants (1) to (14) are shown in Tables 2 to 4. The tables also show the amount of thermosetting compound (A) having an epoxy group in the molecule relative to the total mass of the curable resin (column "Amount of (A)/total curable resin"), the amount of specific curable compound (B) relative to the total mass of the curable resin (column "Amount of (B)/total curable resin"), and the amount of partial epoxy (meth)acrylate (D) relative to the total mass of the curable resin contained in the liquid crystal sealant (column "Amount of (D)/total curable resin").

As is clear from Tables 2 to 4, by using a liquid crystal sealant having a Young's modulus measured at 23°C of 0.5 GPa or more and less than 3.0 GPa, and containing a thermosetting compound (A) having an epoxy group in the molecule and a thermosetting agent (E), the thermosetting agent (E) being a thermosetting agent having a solubility in water at 20°C of 5 g/100 g or less, it was possible to suppress the occurrence of bright spots (roughness) when the liquid crystal panel element was subjected to pressure treatment.

[Examples and Comparative Examples Related to the Second Disclosure]
2-1. Preparation of Sealing Agent 80 parts by mass of the thermosetting compound (A-1), 520 parts by mass of the curing compound (B-1), 120 parts by mass of other curing compound (C-1), 20 parts by mass of the heat curing agent (E-5), 5 parts by mass of the photopolymerization initiator (F-1), 175 parts by mass of silica particles, 70 parts by mass of the fine particle polymer, and 10 parts by mass of the silane coupling agent were thoroughly mixed using a triple roll to obtain a uniform liquid, thereby obtaining a sealing agent (21).

Sealing agents (22) to (33) were obtained in the same manner, except that the types and amounts of materials used were changed as shown in Tables 5 and 6.

The compositions of sealing agents (21) to (33) are shown in Tables 5 and 6. The numerical values given for each component indicate parts by weight unless otherwise specified.

2-2. Evaluation The sealants (21) to (33) prepared above were evaluated for elongation, flexibility, moisture permeability, and liquid crystal contamination by the following methods.

<Growth rate>
The obtained sealant was applied to a release paper with a thickness of 100 μm using an applicator. The applied sealant was then placed in a nitrogen replacement container and purged with nitrogen for 5 minutes, after which it was irradiated with light of 3000 mJ/cm ² (light calibrated with a 365 nm wavelength sensor) and further heated at 120° C. for 1 hour to produce a cured film.

The obtained cured film was cut into strips (length 150 mm, width 10 mm) and then subjected to a tensile test at room temperature (23°C) at a test speed of 10 mm/min using an autograph tensile testing machine (Shimadzu Corporation, AG-X). The elongation was calculated from the distance at which the stress had decreased by 80% or more from the yield point.

<Flexibility>
The obtained cured film was cut into a strip (length 50 mm, width 10 mm), then folded along a mandrel with a diameter of 1.0 mm or 1.5 mm and fixed for 10 seconds. The cured film was removed from the mandrel and allowed to stand on a flat table for 1 minute. The state of the cured film was then visually observed, and the flexibility was evaluated according to the following criteria.
◎ No deformation such as cracks or breaks for the 1.0 mm and 1.5 mm diameter mandrels. ○ There was deformation such as breakage for the 1.0 mm diameter mandrel, but there was no deformation such as cracks or breaks for the 1.5 mm diameter mandrel. △ There was no crack for the 1.5 mm diameter mandrel, but there was deformation such as breakage. × A crack occurred for the 1.5 mm diameter mandrel.

<Moisture permeability>
The obtained sealant was applied to a release paper with a thickness of 300 μm using an applicator. The applied sealant was then placed in a nitrogen replacement container and purged with nitrogen for 5 minutes, after which it was irradiated with light of 3000 mJ/cm ² (light calibrated with a 365 nm wavelength sensor) and further heated at 120° C. for 1 hour to produce a cured film.

Two sheets of cured film were placed on an aluminum cup containing calcium chloride (anhydrous) as a moisture absorbent, and an aluminum ring was placed on top and screwed, after which the initial weight of the entire aluminum cup was measured. The aluminum cup was then placed in a thermostatic chamber set at 60°C and 90% Rh, and after 24 hours had passed, the aluminum cup was taken out and its weight was measured. The obtained weight value was substituted into the following formula to calculate the moisture permeability.
Formula:
Moisture permeability=(weight after test−weight before test)×film thickness/(film area×100)

<Liquid crystal contamination>
0.03 g of the obtained sealant and 0.3 g of liquid crystal (MLC-7026-100, manufactured by Merck) were weighed into a 1 ml beaker and heated at 120° C. for 1 hour. The nematic-isotropic liquid phase transition temperature (NI point) of the liquid crystal contaminated by heating was compared with the NI point of the uncontaminated liquid crystal before heating, and the difference (ΔNI point) was calculated. Note that when a liquid crystal sealant with low liquid crystal contamination is used, the absolute value of the ΔNI point becomes smaller.
Based on the obtained ΔNI points, the sealing agents were evaluated according to the following criteria.
○ ΔNI point is within 2.0°C × ΔNI point is greater than 2.0°C

The results of evaluation of the elongation, flexibility, moisture permeability, and liquid crystal contamination of sealants (22) to (33) are shown in Tables 5 and 6. The tables also show the amount of thermosetting compound (A) having an epoxy group in the molecule relative to the total mass of the curable resin (column "Amount of (A)/total curable resin"), the amount of specific curable compound (B) relative to the total mass of the curable resin (column "Amount of (B)/total curable resin"), and the amount of partial epoxy (meth)acrylate (D) relative to the total mass of the curable resin (column "Amount of (D)/total curable resin").

As is clear from Tables 5 and 6, the liquid crystal sealant of the present invention is able to achieve both high flexibility and low moisture permeability.

This application claims priority to Japanese Patent Application No. 2021-046327, filed March 19, 2021, Japanese Patent Application No. 2021-046329, filed March 19, 2021, and Japanese Patent Application No. 2021-046333, filed March 19, 2021. The matters described in the specifications, claims and abstracts of these applications are incorporated by reference into this application.

The present invention is extremely useful for application to various liquid crystal display panels.

Claims (14)

The Young's modulus of the cured product measured at 23° C. is 0.5 GPa or more and less than 3.0 GPa,
A curable resin containing a thermosetting compound (A) having an epoxy group in the molecule (but not including a partial epoxy (meth)acrylate) ;
and a heat curing agent (E), the heat curing agent (E) having a solubility in water at 20°C of 5 g/100 g or less.
Liquid crystal sealant. The heat curing agent (E) is at least one heat curing agent 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 liquid crystal sealant according to claim 1 . The liquid crystal sealant according to claim 1 or 2, wherein the time until G' and G'' become equal when the liquid crystal sealant at 25°C is heated to 120°C while measuring the storage modulus (G') and loss modulus (G'') with a dynamic viscoelasticity measuring device (rheometer) is 450 seconds or less. The liquid crystal sealant according to any one of claims 1 to 3, wherein the curable resin contains a curable compound (B) having a characteristic ratio represented by the following formula of 4.7 or less, a Tg of 250°C or more and 340°C or less, and a weight average molecular weight (Mw) of 1000 or more.

(In formula (1), <R ₀ ² > is the root-mean-square value of all possible end-to-end distances of the polymer chain. L is the root-mean-square value of the lengths of each structural unit constituting the polymer chain, and n is the number of structural units.) The liquid crystal sealant according to claim 4 , wherein the curable compound (B) is a compound represented by general formula (2):

...General formula (2)
(In general formula (2), _R1 represents a divalent residue derived from a polyepoxy compound, _R2 independently represents a divalent structure obtained by ring-opening a cyclic lactone, _R3 independently represents a linear or branched alkylene group having 1 to 6 carbon atoms, and _R4 independently represents a hydrogen atom or a methyl group.) The liquid crystal sealant according to claim 4 or 5, wherein a content of the curable compound (B) relative to 100 parts by mass of the curable resin is 40 parts by mass or more and 90 parts by mass or less. Contains an inorganic filler (G),
The content of the inorganic filler (G) relative to 100 parts by mass of the curable resin is 20 parts by mass or more and 55 parts by mass or less.
The liquid crystal sealant according to any one of claims 1 to 6. The liquid crystal sealant according to any one of claims 1 to 7, wherein a cured product having a thickness of 0.6 mm has a moisture permeability of less than 50 g/ ^m2 in an environment of 60°C and 90% Rh. A step of applying the liquid crystal sealant according to any one of claims 1 to 8 onto an alignment film of one of a pair of substrates each having an alignment film to form a seal pattern;
dropping liquid crystal onto one of the substrates and within the region of the seal pattern, or onto the other substrate, while the seal pattern is in an uncured state;
a step of overlapping the one substrate and the other substrate via the seal pattern;
curing the seal pattern;
Including,
A method for manufacturing a liquid crystal display panel. The method for manufacturing a liquid crystal display panel according to claim 9, wherein in the step of hardening the seal pattern, the seal pattern is hardened by irradiating the seal pattern with light. The method for manufacturing a liquid crystal display panel according to claim 10, wherein the light irradiated to the seal pattern includes light in the visible light region. The method for manufacturing a liquid crystal display panel according to claim 10 or 11, wherein in the step of hardening the seal pattern, the seal pattern after being irradiated with light is further heated. The method for manufacturing a liquid crystal display panel according to any one of claims 9 to 12, further comprising a step of subjecting the substrate to a pressure treatment after the step of hardening the seal pattern. A pair of substrates each having an alignment film;
a frame-shaped seal member disposed between the alignment films of the pair of substrates;
a liquid crystal layer filled in a space surrounded by the sealing member between the pair of substrates,
The sealing member is a cured product of the liquid crystal sealant according to any one of claims 1 to 8.
LCD display panel.