Liquid crystal sealing agent, liquid crystal display panel using same, and method for manufacturing liquid crystal display panel

Abstract

The present invention addresses the problem of providing a liquid crystal sealing agent that makes it possible to produce a sealing material having adhesive strength and low moisture permeability. The liquid crystal sealing agent for solving the problem comprises a curable compound and a curing agent, wherein the curable compound comprises a cyclized polymerizable compound represented by a specific chemical formula.

Description

Technical Field

[0001] The present invention relates to a liquid crystal sealant, a liquid crystal display panel using the same, and a method for manufacturing the same. Background Art

[0002] A liquid crystal display panel generally comprises a pair of substrates, a frame-shaped sealing material disposed therebetween, and a liquid crystal material enclosed within a region surrounded by the sealing material. Such a liquid crystal display panel is manufactured using a liquid crystal dropping process.

[0003] In the liquid crystal drop process, a liquid crystal sealant is first applied to one of a pair of substrates using a dispensing method to form a rectangular frame-shaped seal pattern. Then, while the liquid crystal sealant is still uncured, liquid crystal material is added dropwise into the frame-shaped seal pattern or to a corresponding area on the other substrate. The substrates are then overlapped under vacuum, and the frame-shaped seal pattern is temporarily cured by irradiating it with light such as ultraviolet light. Afterwards, heating is applied for full curing, thereby producing a liquid crystal display panel.

[0004] In recent years, as LCD panels have become increasingly narrow, the demand for narrower line widths in sealants has also increased. Consequently, sealants are required to maintain comparable or better adhesion to the substrate and moisture resistance than conventional materials, even with these narrow widths. This means achieving a balance between high adhesive strength and low moisture permeability.

[0005] As a method for improving the low moisture permeability of sealing materials, methods of adding inorganic fillers such as talc and alumina are known. For example, Patent Document 1 proposes a sealant for liquid crystal display elements containing a curable resin, a free radical polymerization initiator or a thermosetting agent, and alumina. In addition, Patent Document 2 proposes a sealant for liquid crystal display elements containing a curable resin, a free radical polymerization initiator or a thermosetting agent, and alumina or talc with an aspect ratio of 2 or greater.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-218447

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2013-214056 Summary of the Invention

[0010] Technical problem to be solved by the invention

[0011] However, the method of adding an inorganic filler improves low moisture permeability of the resulting sealing material, but its flexibility is impaired, which leads to a problem of decreased adhesive strength. Thus, adhesive strength and low moisture permeability are generally in a trade-off relationship, and it has been difficult to achieve both in conventional liquid crystal sealants.

[0012] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a liquid crystal sealing agent capable of producing a sealing material having adhesive strength and low moisture permeability, a liquid crystal display panel using the same, and a method for manufacturing the same.

[0013] Technical solutions to technical problems

[0014] The present invention provides a liquid crystal sealing agent including a curable compound and a curing agent, wherein the curable compound includes a cyclopolymerizable compound represented by the following general formula (1).

[0015] [Chemistry 1]

[0016]

[0017] (In general formula (1), R 1 represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, R 2 and R 3 Each independently represents a hydrocarbon group having 1 to 4 carbon atoms, and X represents a single bond, -O-, -S-, or NR 4 (R 4 is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms.

[0018] The present invention further provides a liquid crystal display panel comprising: a pair of substrates; a liquid crystal layer sandwiched between the pair of substrates; and a frame-shaped sealing material disposed between the pair of substrates for sealing the liquid crystal layer, wherein the sealing material is a cured product of the liquid crystal sealant described above.

[0019] The present invention further provides a method for manufacturing a liquid crystal display panel, which includes: a process of preparing a pair of substrates; a process of applying the liquid crystal sealant described above on one of the substrates to form a frame-shaped seal pattern; a process of applying a dummy sealant on the outside of the frame-shaped seal pattern to form a dummy seal pattern; a process of dripping liquid crystal material onto the inside of the frame-shaped seal pattern and / or onto the other substrate when the frame-shaped seal pattern and the dummy seal pattern are not solidified; a process of overlapping the pair of substrates with the liquid crystal material therebetween under a reduced pressure environment; and a process of solidifying the frame-shaped seal pattern and the dummy seal pattern.

[0020] Effects of the Invention

[0021] According to the liquid crystal sealing agent of this invention, the sealing material which has adhesive strength and low moisture permeability can be produced. DETAILED DESCRIPTION

[0022] In this specification, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0023] 1. Liquid crystal sealant

[0024] The liquid crystal sealing compound of this invention only needs to contain a curable resin and a curing agent for curing this curable resin, and may further contain a filler, a silane coupling agent, etc. as needed.

[0025] As mentioned above, with respect to previous liquid crystal sealants, it is difficult to achieve both high bonding strength and low moisture permeability in the sealing material after curing. In contrast, according to the diligent research of the present inventors, it has been clarified that high bonding strength and low moisture permeability can be achieved by including a cyclopolymerizable compound having a specific structure in the liquid crystal sealant. The structure of the cyclopolymerizable compound will be described in detail later. When the cyclopolymerizable compound is polymerized, a structure in which multiple alicyclic structures are connected by ethylene chains is formed. According to this polymer, the rigid alicyclic structure can suppress the intrusion of moisture into the sealing material. On the other hand, in the polymer, moderate flexibility is exerted by the ethylene chain. Therefore, when an external force is applied to the liquid crystal display panel, the sealing material can be deformed following the substrate, and the bonding strength between the substrate and the sealing material becomes very high.

[0026] Hereinafter, each component contained in the liquid crystal sealing compound of this invention is demonstrated in detail.

[0027] 1-1. Curable compounds

[0028] In this specification, the term "curable compound" refers to a compound that is polymerized and cured by energy such as heat or light. The curable compound may contain at least the cyclopolymerizable compound described below, and preferably further contains an epoxy compound, a (meth)acrylic compound, or a (meth)acrylic-modified epoxy compound described below, along with the cyclopolymerizable compound.

[0029] (1) Cyclic polymerizable compounds

[0030] As described above, the curable compound includes a cyclopolymerizable compound having a structure represented by the following general formula (1). The curable compound may include only one type of cyclopolymerizable compound, or may include two or more types. Furthermore, the cyclopolymerizable compound, through polymerization, becomes a polymer having a repeating unit represented by the following general formula (2).

[0031] [Chemistry 2]

[0032]

[0033] In general formula (1) and general formula (2), R 1 represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. The hydrocarbon group more preferably has 1 to 4 carbon atoms.

[0034] As R 1 Specific examples of the groups represented include: a hydrogen atom; a chain saturated hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, a sec-hexyl group, an n-heptyl group, an n-octyl group, a sec-octyl group, a tert-octyl group, a 2-ethylhexyl group, a capryl group, a nonyl group, a decyl group, an undecyl group, a lauryl group, a tridecyl group, a myristyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, a stearyl group, a nonadecyl group, an eicosyl group, a hexacosyl group, and a triacontyl group;

[0035] Alkoxy-substituted chain saturated hydrocarbon groups in which some of the hydrogen atoms of chain saturated hydrocarbon groups such as methoxyethyl, methoxyethoxyethyl, methoxyethoxyethoxyethyl, 3-methoxybutyl, ethoxyethyl, ethoxyethoxyethyl, phenoxyethyl, and phenoxyethoxyethyl are substituted with alkoxy groups;

[0036] A hydroxy-substituted chain saturated hydrocarbon group in which a part of the hydrogen atoms of a chain saturated hydrocarbon group such as hydroxyethyl, hydroxypropyl, and hydroxybutyl are substituted with hydroxyl groups;

[0037] A halogen-substituted chain saturated hydrocarbon group in which a part of the hydrogen atoms of a chain saturated hydrocarbon group such as a fluoroethyl, difluoroethyl, chloroethyl, dichloroethyl, bromoethyl, or dibromoethyl group are substituted with a halogen;

[0038] Chain unsaturated hydrocarbon groups such as vinyl, allyl, methallyl, crotyl, and propargyl, and chain unsaturated hydrocarbon groups in which some of the hydrogen atoms are substituted by alkoxy, hydroxyl, or halogen;

[0039] Alicyclic hydrocarbon groups such as cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, tricyclodecanyl, isobornyl, adamantyl, and dicyclopentadienyl, and alicyclic hydrocarbon groups in which some of the hydrogen atoms are substituted with alkoxy, hydroxyl, or halogen;

[0040] Aromatic hydrocarbon groups such as phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, 4-tert-butylphenyl, benzyl, diphenylmethyl, diphenylethyl, triphenylmethyl, cinnamyl, naphthyl, and anthracenyl, and aromatic hydrocarbon groups in which some of the hydrogen atoms are substituted with alkoxy groups, hydroxy groups, or halogen groups; etc.

[0041] Among them, a hydrogen atom or a chain saturated hydrocarbon group is preferred, and a hydrogen atom or a methyl group is preferred from the viewpoint of less likely to cause steric hindrance during polymerization of the cyclopolymerizable compound.

[0042] In addition, R in the above general formula (1) and general formula (2) 2 and R 3 Each independently represents a hydrocarbon group having 1 to 4 carbon atoms, preferably a hydrocarbon group having 1 to 2 carbon atoms, and particularly preferably a hydrocarbon group having 1 carbon atoms, i.e., a methylene group. 2 and R 3 They can be the same or different.

[0043] Furthermore, X in the above general formula (1) and general formula (2) represents a single bond, -O-, -S-, or NR 4 (R 4 is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms). When X is a single bond, the ring formed when the cyclopolymerizable compound is polymerized becomes an aliphatic hydrocarbon ring. On the other hand, when X is -O-, -S- or NR 4 In the case of X, the ring formed by the polymerization of the cyclopolymerizable compound becomes an alicyclic heterocyclic structure. Among the above, X is preferably -O- or -S-, and particularly preferably -O-. If X is -O-, the polymer of the cyclopolymerizable compound and thus the sealing material are more likely to exhibit flexibility. In addition, the strength of the sealing material is more likely to be improved by hydrogen bonding between the O atom and the group on the substrate surface.

[0044] Specific examples of the cyclopolymerizable compound represented by the general formula (1) include: α-allyloxymethacrylic acid, methyl α-allyloxymethacrylate, ethyl α-allyloxymethacrylate, n-propyl α-allyloxymethacrylate, isopropyl α-allyloxymethacrylate, n-butyl α-allyloxymethacrylate, sec-butyl α-allyloxymethacrylate, tert-butyl α-allyloxymethacrylate, n-pentyl α-allyloxymethacrylate, sec-pentyl α-allyloxymethacrylate, tert-pentyl α-allyloxymethacrylate, n-hexyl α-allyloxymethacrylate, sec-hexyl α-allyloxymethacrylate, n-heptyl α-allyloxymethacrylate, n-octyl α-allyloxymethacrylate, α-allyloxymethacrylate, tert-butyl α-allyloxymethacrylate, tert-pentyl α-allyloxymethacrylate, tert-hex ... -Sec-octyl α-allyloxymethacrylate, tert-octyl α-allyloxymethacrylate, 2-ethylhexyl α-allyloxymethacrylate, octyl α-allyloxymethacrylate, nonyl α-allyloxymethacrylate, decyl α-allyloxymethacrylate, undecyl α-allyloxymethacrylate, lauryl α-allyloxymethacrylate, tridecyl α-allyloxymethacrylate, myristyl α-allyloxymethacrylate, pentadecyl α-allyloxymethacrylate, hexadecyl α-allyloxymethacrylate, heptadecyl α-allyloxymethacrylate, stearyl α-allyloxymethacrylate, nonadecyl α-allyloxymethacrylate, α-allyloxymethyl Eicosyl acrylate, hexadecyl α-allyloxymethacrylate, triacontyl α-allyloxymethacrylate, methoxyethyl α-allyloxymethacrylate, methoxyethoxyethyl α-allyloxymethacrylate, methoxyethoxyethoxyethyl α-allyloxymethacrylate, 3-methoxybutyl α-allyloxymethacrylate, ethoxyethyl α-allyloxymethacrylate, ethoxyethoxyethyl α-allyloxymethacrylate, phenoxyethyl α-allyloxymethacrylate, phenoxyethoxyethyl α-allyloxymethacrylate, hydroxyethyl α-allyloxymethacrylate, hydroxypropyl α-allyloxymethacrylate, hydroxybutyl α-allyloxymethacrylate, Fluoroethyl methacrylate, difluoroethyl α-allyloxymethacrylate, chloroethyl α-allyloxymethacrylate, dichloroethyl α-allyloxymethacrylate, bromoethyl α-allyloxymethacrylate, dibromoethyl α-allyloxymethacrylate, vinyl α-allyloxymethacrylate, allyl α-allyloxymethacrylate, methylallyl α-allyloxymethacrylate, crotyl α-allyloxymethacrylate, propargyl α-allyloxymethacrylate, cyclopentyl α-allyloxymethacrylate, cyclohexyl α-allyloxymethacrylate, 4-methylcyclohexyl α-allyloxymethacrylate, 4-tert-butylcyclohexyl α-allyloxymethacrylate, tricyclodecyl α-allyloxymethacrylate,Isobornyl α-allyloxymethacrylate, adamantyl α-allyloxymethacrylate, dicyclopentadienyl α-allyloxymethacrylate, phenyl α-allyloxymethacrylate, methylphenyl α-allyloxymethacrylate, dimethylphenyl α-allyloxymethacrylate, trimethylphenyl α-allyloxymethacrylate, 4-tert-butylphenyl α-allyloxymethacrylate, benzyl α-allyloxymethacrylate, diphenylmethyl α-allyloxymethacrylate, diphenylethyl α-allyloxymethacrylate, triphenylmethyl α-allyloxymethacrylate, cinnamyl α-allyloxymethacrylate, naphthyl α-allyloxymethacrylate, anthracene α-allyloxymethacrylate, etc.

[0045] Among the above, α-allyloxymethacrylic acid is preferred.

[0046] The amount of the cyclic polymerizable compound relative to the total amount of the curable compound is preferably 1% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 27% by mass or less, and further preferably 10% by mass or more and 20% by mass or less. If the viscosity of the liquid crystal sealant is too low, when the uncured liquid crystal sealant (frame-shaped seal pattern) and the liquid crystal material are sandwiched between a pair of substrates and bonded together, the liquid crystal material easily enters the frame-shaped seal pattern formed by the liquid crystal sealant (this phenomenon is also referred to as "inward impact" in this specification). In contrast, if the amount of the cyclic polymerizable compound is 30% by mass or less relative to the total amount of the curable compound, the viscosity of the liquid crystal sealant is more easily controlled within the desired range, and the above-mentioned inward impact is less likely to occur when manufacturing a liquid crystal display panel. On the other hand, if the amount of the cyclic polymerizable compound is 1% by mass or more relative to the total amount of the curable compound, the bonding strength of the obtained sealing material is more easily improved, and low moisture permeability is more easily achieved.

[0047] In addition, when the liquid crystal sealant contains a filler described later, the amount of the cyclopolymerizable material relative to the total amount of the filler is preferably 3% by mass or more and 300% by mass or less, more preferably 25% by mass or more and 200% by mass or less, and even more preferably 50% by mass or more and 150% by mass or less. When the ratio of the cyclopolymerizable compound to the filler is within this range, the viscosity of the liquid crystal sealant is more easily controlled within the desired range, and the coating properties of the liquid crystal sealant are more easily improved.

[0048] (2) Other curing compounds

[0049] Examples of curable compounds other than the above-mentioned cyclopolymerizable compounds included in the curable compound include epoxy compounds having one or more epoxy groups in the molecule, (meth) acrylic acid compounds having one or more (meth) acryloyl groups in the molecule, and (meth) acrylic acid-modified epoxy compounds having (meth) acryloyl groups and epoxy groups in the molecule. Furthermore, in this specification, the so-called (meth) acryloyl group means methacryloyl, acryloyl, and both of them. In addition, the so-called (meth) acrylic acid means methacrylic acid, acrylic acid, and both of them, and the so-called (meth) acrylate means methacrylate, acrylate, and both of them.

[0050] Epoxy compounds

[0051] In this specification, an epoxy compound refers to a compound having one or more epoxy groups in the molecule. However, in this specification, epoxy compounds do not include compounds having both epoxy and (meth)acryloyl groups. The curable compound may include only one epoxy compound or two or more.

[0052] In addition, the number of epoxy groups contained in one molecule of the epoxy compound may be one or more. If the curable compound includes an epoxy compound, the thermosetting property of the liquid crystal sealant tends to become good. Examples of epoxy compounds include well-known epoxy compounds, such as aromatic epoxy compounds, aliphatic epoxy compounds, and alicyclic epoxy compounds. Among them, aromatic epoxy compounds are preferably used in terms of easily achieving low moisture permeability of the obtained sealing material.

[0053] Examples of aromatic epoxy compounds include aromatic polyglycidyl ether compounds obtained by reacting aromatic diols represented by bisphenol A, bisphenol S, bisphenol F, bisphenol AD, etc., or diols modified by ethylene glycol, propylene glycol, alkane diol, etc., with epichlorohydrin; novolac-type polyglycidyl ether compounds obtained by reacting polyphenols represented by novolac resins derived from phenol or cresol and formaldehyde, polyalkenylphenols, or copolymers thereof, with epichlorohydrin; glycidyl ether compounds of xylylene phenol resins, etc.

[0054] Among them, preferred are cresol novolac-type epoxy compounds, phenol novolac-type epoxy compounds, bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, trisphenol methane-type epoxy compounds, trisphenol ethane-type epoxy compounds, trisphenol-type epoxy compounds, dicyclopentadiene-type epoxy compounds, diphenyl ether-type epoxy compounds, or biphenyl-type epoxy compounds.

[0055] The epoxy compound may be in either liquid or solid form. Solid epoxy compounds are preferred because they easily achieve low moisture permeability in the sealing material. The softening point of the solid epoxy compound is preferably 40°C to 150°C. The softening point can be measured using the ring and ball method specified in Japanese Industrial Standard (JIS) K7234.

[0056] The weight average molecular weight of the epoxy compound is preferably 500 to 10000, and more preferably 1000 to 5000. The weight average molecular weight of the epoxy compound is measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0057] The total amount of the epoxy compound is preferably 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 40% by mass or less relative to the total amount of the curable compound. If the amount of the epoxy compound is 5% by mass or more, the moisture permeability of the sealing material is likely to be further reduced. On the other hand, if the amount of the epoxy compound is 60% by mass or less, the amount of the cyclopolymerizable compound and the like is relatively increased, and the photopolymerizability of the obtained sealing material is likely to be further improved, or the adhesive strength and the like are likely to be further improved.

[0058] (Meth) acrylic acid compounds

[0059] In this specification, a (meth)acrylic compound is defined as a compound having one or more (meth)acryloyl groups in the molecule. However, in this specification, the (meth)acrylic compound does not include the aforementioned cyclopolymerizable compounds or compounds having (meth)acryloyl and epoxy groups. The curable compound may include only one (meth)acrylic compound or two or more.

[0060] The number of (meth)acrylic acid groups contained in one molecule of a (meth)acrylic acid compound may be one or two or more. Examples of (meth)acrylic acid compounds containing one (meth)acrylic acid group in one molecule include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate.

[0061] Examples of (meth)acrylic compounds having two or more (meth)acryloyl groups in one molecule include di(meth)acrylates derived from polyethylene glycol, propylene glycol, polypropylene glycol, and the like; di(meth)acrylates derived from tris(2-hydroxyethyl)isocyanurate; di(meth)acrylates derived from diols obtained by adding 4 or more ethylene oxide or propylene oxide to 1 mol of neopentyl glycol; di(meth)acrylates derived from diols obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A or bisphenol F (bisphenol A type or bisphenol F type epoxy (meth)acrylates); di(meth)acrylates or tri(meth)acrylates derived from polyols obtained by adding 2 or 3 mol of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane; and diols obtained by adding 4 or more ethylene oxide or propylene oxide to 1 mol of bisphenol A. di(meth)acrylate of 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; tri(acryloyloxyethyl)isocyanurate; caprolactone-modified tri(acryloyloxyethyl)isocyanurate; caprolactone-modified tri(methacryloyloxyethyl)isocyanurate; alkyl-modified poly(meth)acrylate of dipentaerythritol; caprolactone-modified poly(meth)acrylate of dipentaerythritol; hydroxypivalate neopentyl glycol di(meth)acrylate; caprolactone-modified hydroxypivalate neopentyl glycol di(meth)acrylate; ethylene oxide-modified phosphoric acid (meth)acrylate; ethylene oxide-modified alkylated phosphoric acid (meth)acrylate; and oligomeric (meth)acrylates of neopentyl glycol, trimethylolpropane and pentaerythritol, etc. Among these, di(meth)acrylates derived from diols obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A or bisphenol F (bisphenol A-type or bisphenol F-type epoxy (meth)acrylates) are preferred.

[0062] The weight average molecular weight of the (meth)acrylic acid-based compound measured by gel permeation chromatography (GPC) is preferably 200 to 10,000, more preferably 200 to 5,000.

[0063] The weight average molecular weight of the (meth)acrylic compound is preferably about 310 to 1000. The weight average molecular weight is, for example, a value measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0064] Here, relative to the total amount of curable compounds, the total amount of (meth) acrylic acid compounds is preferably 3% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 40% by mass or less. If the total amount of (meth) acrylic acid compounds is 3% by mass or more, the photocurability of the liquid crystal sealant tends to become good. On the other hand, if the total amount of (meth) acrylic acid compounds is 60% by mass or less, relatively, the amount of the cyclopolymerizable compound and the epoxy compound becomes sufficient, and the adhesive strength and low moisture permeability of the obtained sealing material tend to become good.

[0065] (Meth) acrylic acid modified epoxy compound

[0066] In this specification, a (meth)acrylic acid-modified epoxy compound refers to a compound having one or more epoxy groups and one or more (meth)acryloyl groups in a molecule. The curable compound may contain only one (meth)acrylic acid-modified epoxy compound or two or more.

[0067] The number of epoxy groups and (meth)acryloyl groups in the (meth)acrylic acid-modified epoxy compound is not particularly limited and may be only one or two or more. The (meth)acrylic acid-modified epoxy compound has good compatibility with the aforementioned cyclopolymerizable compound, the aforementioned epoxy-based compound, and the aforementioned acrylic acid-based compound. Therefore, if a (meth)acrylic acid-modified epoxy compound is included as a curable compound, the compatibility of different types of curable compounds becomes very good.

[0068] A (meth)acrylic acid-modified epoxy compound is obtained by modifying at least one epoxy group of a difunctional or higher-functional epoxy compound with a (meth)acryloyl group. This (meth)acrylic acid-modified epoxy compound can be obtained, for example, by reacting a difunctional or higher-functional epoxy compound with (meth)acrylic acid in the presence of a basic catalyst.

[0069] The epoxy compound modified with a (meth)acryloyl group can be any multifunctional epoxy compound having two or more epoxy groups in the molecule. From the perspective of suppressing excessive crosslinking density and excessive reduction in the adhesive strength of the sealing material, a difunctional epoxy compound is preferred. Examples of difunctional epoxy compounds include bisphenol-type epoxy compounds (bisphenol A type, bisphenol F type, 2,2'-diallylbisphenol A type, bisphenol AD ​​type and hydrogenated bisphenol type, etc.), biphenyl-type epoxy compounds and naphthalene-type epoxy compounds. Among them, from the perspective of easy application of liquid crystal sealants, bisphenol-type epoxy compounds of bisphenol A type and bisphenol F type are preferred. Compared with (meth)acrylic acid-modified epoxy compounds derived from biphenyl ether-type epoxy compounds, (meth)acrylic acid-modified epoxy compounds derived from bisphenol-type epoxy compounds have advantages such as excellent application properties.

[0070] The ratio of the number of moles of the (meth)acryloyl group in the (meth)acrylic acid-modified epoxy compound to the number of moles of the epoxy group is preferably 1 or more, more preferably 2 or more. By increasing the ratio of the number of moles of the (meth)acryloyl group, elution of the liquid crystal sealing agent into the liquid crystal is easily suppressed.

[0071] The weight average molecular weight of the (meth)acrylic acid-modified epoxy compound measured by gel permeation chromatography (GPC) is preferably 300 to 500.

[0072] In addition, the amount of the (meth) acrylic acid modified epoxy compound is preferably 10% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 60% by mass or less, relative to the total amount of the curable composition. If the amount of the (meth) acrylic acid modified epoxy compound is 10% by mass or more, it is easy to improve the compatibility of the above-mentioned cyclopolymerizable compound, acrylic compound and epoxy compound. On the other hand, if the amount of the (meth) acrylic acid modified epoxy compound is 80% by mass or less, the amount of the cyclopolymerizable compound and the like is easy to become sufficient, and in the obtained sealing material, it is easier to achieve low moisture permeability or high adhesive strength.

[0073] ·other

[0074] The curable compound may further contain curable compounds other than those described above, within a range not impairing the object and effects of the present invention.

[0075] Here, relative to the total amount of liquid crystal sealant, the total amount of curable composition is preferably 40% by mass or more and 90% by mass or less, more preferably 60% by mass or more and 80% by mass or less. If the total amount of curable composition is 40% by mass or more, then in the liquid crystal display panel, leakage of liquid crystal is easily suppressed by sealing material. On the other hand, if the total amount of curable composition is 90% by mass or less, then the amount of curing agent etc. described later becomes sufficient, and it is easy to make the curability of liquid crystal sealant better, or it is easy to adjust the viscosity of liquid crystal sealant to the desired range.

[0076] 1-2. Curing agent

[0077] The liquid crystal sealing agent contains a curing agent. Examples of the curing agent include a thermosetting agent for thermally curing the liquid crystal sealing agent and a photopolymerization initiator for photocuring the liquid crystal sealing agent.

[0078] (1) Thermal curing agent

[0079] There are no particular limitations on the thermosetting agent, as long as it can thermoset the aforementioned epoxy compounds and (meth)acrylic acid-modified epoxy compounds. However, the thermosetting agent is preferably a latent thermosetting agent. A latent thermosetting agent is a compound that does not cure epoxy compounds, (meth)acrylic acid-modified epoxy compounds, etc. under normal storage conditions (such as room temperature and visible light), but cures these compounds upon heating. Latent thermosetting agents are preferably curing agents that can cure by ring-opening the epoxy groups of the aforementioned curable compounds (hereinafter also referred to as "epoxy curing agents").

[0080] The melting point of the epoxy curing agent is preferably 50°C to 250°C, more preferably 100°C to 200°C, and further preferably 150°C to 200°C from the viewpoint of improving the viscosity stability of the liquid crystal sealing agent and not impairing the moisture resistance of the obtained sealing material.

[0081] Examples of epoxy curing agents (thermal curing agents) include dihydrazide-based thermal latent curing agents, imidazole-based thermal latent curing agents, amine adduct-based thermal latent curing agents, and polyamine-based thermal latent curing agents. The liquid crystal sealant may contain only one of these or two or more.

[0082] Examples of the dihydrazide-based thermal latent curing agent include adipic acid dihydrazide, 1,3-bis(hydrazinocarbonylethyl)-5-isopropylhydantoin, 7,11-octadecadiene-1,18-dicarbohydrazide, dodecanedioic acid dihydrazide, and sebacic acid dihydrazide.

[0083] Examples of the imidazole-based thermal latent curing agent include 2,4-diamino-6-[2′-ethylimidazolyl-(1′)]-ethyltriazine and 2-phenylimidazole.

[0084] Amine adduct-based latent heat curing agents are formed by reacting an amine compound with a catalytically active compound with an adduct compound. Examples of commercially available amine adduct-based latent heat curing agents include Amicure PN-40, Amicure PN-23, Amicure PN-31, Amicure PN-H, Amicure MY-24, and Amicure MY-H (all manufactured by Ajinomoto Precision Technology Co., Ltd.).

[0085] Polyamine-based thermal latent curing agents are obtained by reacting amines with epoxy resins and have a polymer structure. Examples of commercially available products include Adeka Hardener EH4339S and Adeka Hardener EH4357S (both manufactured by ADEKA Corporation).

[0086] Among the above, from the viewpoints of availability, compatibility with other components, etc., dihydrazide-based thermal latent curing agents, amine adduct-based thermal latent curing agents, polyamine-based thermal latent curing agents, and imidazole-based thermal latent curing agents are preferred, and dihydrazide-based thermal latent curing agents are particularly preferred.

[0087] The amount of the thermosetting agent is preferably 3 mass % or more and 30 mass % or less, more preferably 3 mass % or more and 20 mass % or less, further preferably 5 mass % or more and 20 mass % or less, relative to the total amount of the liquid crystal sealing compound.

[0088] (2) Photopolymerization initiator

[0089] The photopolymerization initiator is not particularly limited as long as it is a compound that can initiate curing (polymerization) of the aforementioned cyclopolymerizable compound, acrylic compound, or (meth)acrylic acid-modified epoxy compound. The photopolymerization initiator may be a self-cleaving type or a hydrogen abstraction type. The liquid crystal sealant may contain only one type of photopolymerization initiator or two or more types.

[0090] Examples of the self-cleaving photopolymerization initiator include alkylphenone compounds (e.g., benzyl dimethyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethane-1-one (manufactured by BASF, IRGACURE 651); α-aminoalkylphenone compounds such as 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one (manufactured by BASF, IRGACURE 907); and 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, IRGACURE 907). 184) and other α-hydroxyalkyl phenone compounds; for example, acyl phosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide; for example, titanocene compounds such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium; for example, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)phenyl Acetophenone compounds such as -(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone; benzoylformate ester compounds such as methyl benzoylformate; benzoin ether compounds such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; and oxime ester compounds such as 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzoyloxime)] (manufactured by BASF, IRGACURE OXE01) and ethylone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (manufactured by BASF, IRGACURE OXE02).

[0091] Examples of hydrogen abstraction type photopolymerization initiators include benzophenone, methyl o-benzoylbenzoate-4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetrakis(tert-butylcarbonylperoxy)benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, and the like; and thioxanthone, 2-chlorothioxanthone (manufactured by Tokyo Chemical Industry Co., Ltd.), 1-chloro-4-propoxythioxanthone, 1-chloro-4-ethoxythioxanthone (manufactured by Lambson Limited, Speedcure CPTX), 2-isopropylthioxanthone (manufactured by Lambson Limited, Speedcure ITX), 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone (manufactured by Lambson Chemical Industry Co., Ltd.). Limited, Speedcure DETX), 2,4-dichlorothioxanthone and other thioxanthone-based compounds; anthraquinone-based compounds such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-hydroxyanthraquinone (manufactured by Tokyo Chemical Industry Co., Ltd., 2-Hydroxyanthraquinone), 2,6-dihydroxyanthraquinone (manufactured by Tokyo Chemical Industry Co., Ltd., Anthraflavic Acid), 2-hydroxymethylanthraquinone (manufactured by Junsei Chemical Co., Ltd., 2-(Hydroxymethyl)anthraquinone) and benzoyl-based compounds.

[0092] The absorption wavelength of the photopolymerization initiator is not particularly limited; for example, it preferably absorbs light with a wavelength of 360 nm or longer. It is more preferred to absorb light in the visible light region, and particularly preferably, light with a wavelength of 360 nm to 430 nm. If the photopolymerization initiator has an absorption wavelength within this range, the liquid crystal sealant can be cured by irradiation with visible light, significantly minimizing the effects on liquid crystal materials and the like. In this specification, the term "visible light region" refers to the wavelength range of 360 nm to 780 nm.

[0093] Examples of photopolymerization initiators that absorb light having a wavelength of 360 nm or longer include alkylphenone compounds, acylphosphine oxide photopolymerization initiators, titanocene photopolymerization initiators, oxime ester photopolymerization initiators, thioxanthone photopolymerization initiators, and anthraquinone photopolymerization initiators. Preferred are oxime ester photopolymerization initiators, thioxanthone photopolymerization initiators, and anthraquinone photopolymerization initiators, with oxime ester photopolymerization initiators, thioxanthone photopolymerization initiators, and anthraquinone photopolymerization initiators being particularly preferred.

[0094] Furthermore, the structure of the photopolymerization initiator can be determined by combining high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC / MS) with nuclear magnetic resonance (NMR) or infrared (IR) analysis.

[0095] In addition, the molecular weight of the photopolymerization initiator is, for example, preferably 200 or more and 5000 or less. If the molecular weight is 200 or more, when the liquid crystal sealant contacts the liquid crystal material, the photopolymerization initiator is not easily dissolved into the liquid crystal material. On the other hand, if the molecular weight is 5000 or less, the compatibility of the photopolymerization initiator and the curable compound is improved, and the photocurability of the liquid crystal sealant tends to become good. The molecular weight of the photopolymerization initiator is more preferably 230 or more and 3000 or less, and further preferably 230 or more and 1500 or less.

[0096] The molecular weight of the photopolymerization initiator 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).

[0097] Specifically, a sample solution of a photopolymerization initiator dissolved in tetrahydrofuran (THF) is prepared and analyzed by high-performance liquid chromatography (HPLC). The area percentage of the detected peaks (the ratio of the area of ​​each peak to the total) is then calculated to confirm the presence of a main peak. A main peak is defined as the peak with the highest intensity (the peak with the highest peak height) among all peaks detected at a characteristic detection wavelength for 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 determined using liquid chromatography-mass spectrometry (LC / MS).

[0098] The amount of the photopolymerization initiator is preferably 0.01% to 10% by mass relative to the total amount of the compound having an unsaturated double bond in the curable compound (for example, the total amount of the above-mentioned cyclopolymerizable compound, (meth) acrylic acid compound, and (meth) acrylic acid-modified epoxy compound). If the amount of the photopolymerization initiator is 0.01% by mass or more relative to the total amount of the compound having an unsaturated double bond, the photocurability of the liquid crystal sealant tends to become good. On the other hand, if the content of the photopolymerization initiator is 10% by mass or less, the photopolymerization initiator is not easily eluted into the liquid crystal. The content of the photopolymerization initiator is more preferably 0.1% to 5% by mass, further preferably 0.1% to 3% by mass, and particularly preferably 0.1% to 2.5% by mass relative to the total amount of the compound having an unsaturated double bond in the curable compound.

[0099] 1-3. Filler

[0100] The liquid crystal sealant preferably contains a filler. If the liquid crystal sealant contains a filler, the viscosity of the liquid crystal sealant is more easily controlled within a desired range. In addition, the moisture permeability of the obtained sealing material is further reduced. Examples of fillers include inorganic fillers, core-shell microparticles, and the like.

[0101] (1) Inorganic fillers

[0102] The inorganic filler not only imparts predetermined hardness and linear expansion properties to the obtained sealing material, but also functions to further enhance the low moisture permeability of the sealing material.

[0103] Examples of inorganic fillers include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, titanium nitride, aluminum oxide other than those listed above, zinc oxide, silica, potassium titanate, kaolin, talc, glass beads, sericite, activated clay, bentonite, aluminum nitride, and silicon nitride. Among these, silica and talc are preferred.

[0104] The shape of the inorganic filler can be a fixed shape such as spherical, plate-like, needle-like, or an amorphous shape. When the inorganic filler is spherical, the average primary particle size of the inorganic filler is preferably 1.5 μm or less. In addition, the specific surface area of ​​the inorganic filler is preferably 0.5 m 2 / g or more and 20 m 2 / g or less. The average primary particle size of the inorganic filler can be measured by the laser diffraction method described in JIS Z8825 (2013). The specific surface area of ​​the filler can be measured by the BET method described in JIS Z8830 (2013).

[0105] Relative to the total amount of curable compound, the amount of inorganic filler in liquid crystal sealant is preferably 2% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, further preferably 5% by mass or more and 20% by mass or less. The more the content of inorganic filler, the easier it is to lower the moisture permeability of the obtained sealing material, but if the content is too much, the flexibility of the sealing material is sometimes impaired. Therefore, the above range is preferred.

[0106] (2) Core-shell particles

[0107] Core-shell type fine particles are fine particles comprising a core having desired physical properties and a shell covering the core. The shell can enhance compatibility with other components or partially react with other components.

[0108] Examples of core-shell type fine particles include organic fine particles having an elastic core composed of conjugated diene rubber, silicone rubber, or the like, and a shell composed of a polymer such as (meth)acrylate, vinyl monomer, or epoxy monomer.

[0109] In addition, another example of core-shell type microparticles also includes following microparticles, described microparticles have the core comprising inorganic particles and the shell portion comprising the polymer layer covering the core, and have the functional group comprising carbon-carbon double bond on the surface. The example of the functional group comprising carbon-carbon double bond possessed by the core-shell type microparticles includes vinyl, allyl, acrylic acid, methacrylic acid etc. Moreover, the example of the core in the core-shell type microparticles includes the particles identical with the above-mentioned inorganic filler. Wherein, with regard to the viewpoint of excellent thermal stability, preferably silica particles.

[0110] The amount of the core-shell type fine particles relative to the total amount of the curable compound is preferably 2% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less. If the content of the core-shell type fine particles is within this range, it is easy to adjust the physical properties of the obtained sealing material to the desired range.

[0111] (3) Others

[0112] Fillers other than those mentioned above may be contained within a range not impairing the object and effects of the present invention. For example, organic fine particles other than a core-shell structure may be further contained.

[0113] As described above, if the amount of filler and the amount of cyclopolymerizable compound satisfy a prescribed relationship, the physical properties of the liquid crystal sealant, such as viscosity, can be easily controlled within a desired range, the coating properties of the liquid crystal sealant become good, or intrusion is less likely to occur when manufacturing a liquid crystal display panel. Here, the total amount of filler is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, relative to the total amount of the liquid crystal sealant. If the total amount of filler is within the above range, it is easy to adjust the various physical properties of the liquid crystal sealant to the desired range.

[0114] 1-4. Others

[0115] The liquid crystal sealing compound may further contain a thermal radical generator, organic fine particles, a coupling agent such as a silane coupling agent, an ion scavenger, an ion exchanger, a leveling agent, a pigment, a dye, a sensitizer, a plasticizer, and a defoaming agent in addition to the above components.

[0116] Examples of the thermal radical polymerization initiator include organic peroxides, azo compounds, benzoins, benzoin ethers, and acetophenones.

[0117] Examples of the silane coupling agent include vinyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane.

[0118] The amount of the silane coupling agent is preferably 0.01% by mass or more and 5% by mass or less relative to the total amount of the liquid crystal sealant. When the content of the silane coupling agent is 0.01% by mass or more, the adhesive strength between the sealing material and the substrate can be further improved.

[0119] The liquid crystal sealing compound may further contain a spacer for adjusting the gap of a liquid crystal display panel, etc.

[0120] The total amount of other components is preferably 0.1% by mass or more and 50% by mass or less relative to the total amount of liquid crystal sealing agent. When the total amount is 50% by mass or less, the viscosity of the liquid crystal sealing agent is unlikely to increase excessively, and the coating stability of the liquid crystal sealing agent is unlikely to be impaired.

[0121] 1-5. Viscosity of Liquid Crystal Sealant

[0122] The viscosity of the liquid crystal sealant measured at 25°C and 2.5 rpm using an E-type viscometer is preferably 200 Pa·s to 450 Pa·s, more preferably 300 to 400 Pa·s. When the viscosity is within this range, the sealant can be applied with a dispenser. Furthermore, when the viscosity of the liquid crystal sealant is within this range, the aforementioned internal impact is less likely to occur.

[0123] 2. Liquid crystal display panel and manufacturing method thereof

[0124] The liquid crystal display panel of the present invention includes: a pair of substrates; a liquid crystal layer sandwiched between the pair of substrates; and a frame-shaped sealing material disposed between the pair of substrates for sealing the liquid crystal layer.

[0125] One of the pair of substrates is the display substrate, and the other is the opposing substrate. Both are transparent substrates. The transparent substrate can be made of inorganic materials such as glass, or plastics such as polycarbonate, polyethylene terephthalate, polyethersulfone, and polymethyl methacrylate (PMMA).

[0126] Thin-film transistors (TFTs), color filters, black matrix, and other components can be arranged in a matrix on the surfaces of a pair of substrates (a display substrate and a counter substrate). Alignment films are also typically placed on the surfaces of the display substrate and the counter substrate. These alignment films are films containing well-known organic or inorganic alignment agents.

[0127] The liquid crystal layer is a layer containing a liquid crystal material sealed in a region surrounded by a pair of substrates and a sealing material. The liquid crystal material is the same as a known liquid crystal material.

[0128] The sealing material is a frame-shaped member disposed between a pair of substrates and used to seal liquid crystal. The sealing material is a cured product of the liquid crystal sealant.

[0129] The above-mentioned liquid crystal display panel is manufactured using the liquid crystal sealant of the present invention. The manufacturing method of the liquid crystal display panel generally includes a liquid crystal dropping process and a liquid crystal injection process. The liquid crystal display panel of the present invention is preferably manufactured using the liquid crystal dropping process.

[0130] The method for manufacturing a liquid crystal display panel using a liquid crystal dropping process includes:

[0131] 1) The process of preparing a pair of substrates;

[0132] 2) forming a frame-shaped seal pattern on one of the pair of substrates using the liquid crystal sealant;

[0133] 3) applying a dummy sealant on the outer side of the frame-shaped seal pattern to form a dummy seal pattern;

[0134] 4) a step of dripping a liquid crystal material onto the inner side of an area surrounded by the frame-shaped seal pattern on one substrate and / or a corresponding area on the other substrate while the frame-shaped seal pattern and the dummy seal pattern are not solidified;

[0135] 5) a step of overlapping one substrate with the other substrate via a liquid crystal material under a reduced pressure environment; and

[0136] 6) A step of curing the frame-shaped seal pattern and the dummy seal pattern.

[0137] Furthermore, both the step 2) and the step 3) may be performed first. In addition, after the step 6), a step of removing the region where the dummy seal pattern is formed may be further performed.

[0138] In the step 1), a display substrate and a counter substrate are generally prepared on which TFTs, color filters, a black matrix, and an alignment film are arranged in a matrix.

[0139] In step 2), the area to which the liquid crystal sealant is applied can be appropriately selected according to the structure of the liquid crystal display panel. The liquid crystal sealant application method is not particularly limited as long as the liquid crystal sealant can be applied to a desired width. For example, application can be performed using a dispenser.

[0140] In step 3), the area to which the dummy sealant is applied can be appropriately selected based on the structure of the liquid crystal display panel. The dummy sealant may be the same as or different from the liquid crystal sealant. Furthermore, when the dummy sealant is different from the liquid crystal sealant, the composition of the dummy sealant is not particularly limited and is the same as known dummy sealants. The dummy sealant can also be applied using a dispenser, etc.

[0141] Here, the dummy seal pattern is arranged with a gap between the seal pattern. Forming this dummy seal pattern creates a reduced pressure space between the dummy seal and the seal material when the pair of substrates are overlapped in step 5) described later. This allows the pair of substrates to be securely fixed.

[0142] In step 4), the liquid crystal material is dripped onto the specified area. Here, the uncured state of the frame-shaped seal pattern and the dummy seal pattern refers to a state in which the curing reaction of the liquid crystal sealant and the dummy sealant has not yet reached the gel point. Therefore, in step 4), to prevent the liquid crystal sealant from dissolving into the liquid crystal, the frame-shaped seal pattern may be pre-irradiated with light or heated to semi-cure it. Furthermore, if liquid crystal is dripped onto another substrate in step 4), when the two substrates with alignment films are overlapped in step 5), the liquid crystal is dripped so that the liquid crystal is contained within the frame-shaped seal pattern.

[0143] In the process of 5), one of the substrates is overlapped with the other substrate via the liquid crystal material under a reduced pressure environment. Since the liquid crystal materials are overlapped under a reduced pressure environment in this way, as described above, the obtained sealing material and the dummy seal are in a reduced pressure state. However, when a pair of substrates are overlapped in the process of 5), the frame-shaped sealing pattern is not solidified. Therefore, when a general liquid crystal sealant is used, the liquid crystal material sometimes enters the interior of the frame-shaped sealing pattern (causing inward impact). In contrast, in the above-mentioned liquid crystal sealant, such inward impact is not easily generated. In addition, especially when the above-mentioned liquid crystal sealant contains filler, inward impact is even less likely to occur.

[0144] In step 6), curing by light irradiation and subsequent curing by heating may also be performed. Curing by light irradiation allows the liquid crystal sealant (and dummy sealant) to be cured in a short period of time, thereby suppressing dissolution of the liquid crystal sealant into the liquid crystal. Combining curing by light irradiation with curing by heating reduces light-induced damage to the liquid crystal layer compared to curing by light irradiation alone.

[0145] The light used for irradiation can be appropriately selected based on the type of photopolymerization initiator in the liquid crystal sealant (and dummy sealant). Light in the visible light range is preferred, for example, preferably light with a wavelength of 370 nm to 450 nm. This is because light of these wavelengths causes relatively little damage to the liquid crystal material and drive electrodes. Light irradiation can be performed using known light sources that emit ultraviolet light or visible light. For irradiation with visible light, high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, xenon lamps, fluorescent lamps, and the like can be used.

[0146] The light irradiation energy may be any energy that can cure the curable compound. The light curing time depends on the composition of the liquid crystal sealing compound, but is, for example, about 10 minutes.

[0147] The heat curing temperature also depends on the composition of the liquid crystal sealing agent and the dummy sealing agent, but is, for example, 120° C., and the heat curing time is about 2 hours.

[0148] Example

[0149] Hereinafter, the present invention will be described with reference to Examples, but the scope of the present invention is not to be construed as being limited by the Examples.

[0150] 1. Material Preparation

[0151] The following compounds were prepared as materials used in Examples and Comparative Examples.

[0152] (1) Curing compounds

[0153] (Cyclopolymerizable compound)

[0154] Curable compound (A-1): a cyclopolymerizable compound represented by the following general formula (1A) (trade name "AOMA", manufactured by Nippon Shokubai Co., Ltd.)

[0155] [Chemistry 3]

[0156]

[0157] (Other curing compounds)

[0158] Curable compound (A-2): Bisphenol A diacrylate (Ebecryl 3700, manufactured by Daicel-Allnex)

[0159] Curable compound (A-3): tris-(2-acryloyloxyethyl)isocyanurate represented by the following formula (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-9300-2CL)

[0160] [Chemistry 4]

[0161]

[0162] Curable compound (A-4): Ethoxylated bisphenol A diacrylate represented by the following formula (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-BPE-4)

[0163] [Chemistry 5]

[0164]

[0165] (where m+n=4)

[0166] Curable compound (A-5): Bisphenol F epoxy resin (Mitsubishi Chemical Corporation, YL983U)

[0167] Curable compound (A-6): Acrylic modified epoxy resin (manufactured by KSM, BAEM-50)

[0168] (2) Curing agent

[0169] Thermal curing agent: Amine adduct type curing agent (manufactured by Ajinomoto Precision Technology Co., Ltd., PN-50)

[0170] Photopolymerization initiator: Oxime ester photopolymerization initiator (manufactured by BASF Japan, IRGACURE OXE02)

[0171] (3) Filler

[0172] Silica particles (Admatechs, SO-C1)

[0173] Core-shell microparticles (manufactured by Aica Industries, F351)

[0174] (4) Silane coupling agent

[0175] KBM403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0176] 2. Preparation of Liquid Crystal Sealant

[0177] (Example 1)

[0178] 100 parts by mass of a curable compound (A-1), 70 parts by mass of a curable compound (A-2), 100 parts by mass of a curable compound (A-5), 400 parts by mass of a curable compound (A-6), 130 parts by mass of a thermosetting agent, 10 parts by mass of a photopolymerization initiator, 100 parts by mass of silica particles, 100 parts by mass of core-shell type fine particles, and 10 parts by mass of a silane coupling agent were mixed using a triple roll mill to obtain a liquid crystal sealing compound.

[0179] (Examples 2 to 9 and Comparative Examples 1 and 2)

[0180] Except having changed into the composition shown in Table 1, it carried out similarly to Example 1, and prepared a liquid crystal sealing compound.

[0181] 3. Evaluation

[0182] The obtained cured product of the liquid crystal sealing agent was evaluated for adhesive strength, moisture permeability (low moisture permeability), inward impact resistance, and drawing properties by the following methods.

[0183] (Adhesion strength)

[0184] The obtained liquid crystal sealing agent was formed into a 38 mm × 38 mm square frame-shaped sealing pattern (cross-sectional area 2500 μm) on a 40 mm × 45 mm glass substrate (RT-DM88-PIN, EHC) on which a transparent electrode and an alignment film were previously formed using a dispenser (Shotmaster, manufactured by Musashi Engineering). 2 ).

[0185] Next, the paired glass substrates were bonded together under reduced pressure in a manner perpendicular to the glass substrate on which the frame-shaped seal pattern was formed, and then exposed to the atmosphere. The two bonded glass substrates were then kept in a light-shielding box for 1 minute and then irradiated with 3000 mJ / cm 2 The frame-shaped seal pattern was cured by irradiating the film with light including visible light (light with a wavelength of 370 nm to 450 nm) and further heating at 120° C. for 1 hour to obtain a test piece.

[0186] Using an indentation tester (Model 210, manufactured by Intesco), vertical indentation was applied at a speed of 5 mm / minute to the portion of the obtained test piece 4.5 mm outside the corner of the frame-shaped seal pattern. This procedure was repeated for 10 glass substrates (n=10), and the number of cracked glass substrates was counted. The adhesive strength was then evaluated according to the following criteria.

[0187] ◎: 10 glass substrates were cracked

[0188] ○: The number of cracked glass substrates is 6 to 9

[0189] △: The number of cracks on the glass substrate is 1 to 5

[0190] ×: The number of cracked glass substrates is 0

[0191] The greater the number of cracks in the glass substrate, the higher the adhesive strength can be judged to be. If it is △ or above, it is a level that is not a problem in practical use and is judged to be good.

[0192] (moisture resistance)

[0193] The obtained liquid crystal sealant was applied to a release paper with a thickness of 100 μm using an applicator. The applied liquid crystal sealant was then placed in a nitrogen-purged container and flushed with nitrogen for 5 minutes, followed by irradiation with 3000 mJ / cm 2 The film was irradiated with light (light calibrated by a sensor with a wavelength of 365 nm) and then heated at 120° C. for 1 hour to produce a cured film.

[0194] Two cured films were placed on an aluminum cup filled with anhydrous calcium chloride as a moisture absorbent. An aluminum ring was then placed and screwed in place. The initial weight of the entire cup was measured. The cup was then placed in a thermostatic chamber set at 60°C and 90% RH. After 24 hours, the cup was removed and weighed. The obtained weight was substituted into the following formula to calculate the moisture permeability.

[0195] Calculation formula:

[0196] Water vapor permeability = (weight after test - weight before test) × film thickness / (film area × 100)

[0197] Then, evaluation was performed based on the following criteria.

[0198] ◎: Moisture permeability 60 g / m 2 the following

[0199] ○: Moisture permeability exceeds 60 g / m 2 And 80 g / m 2 the following

[0200] △: Moisture permeability exceeds 80 g / m 2 and 100 g / m 2 the following

[0201] ×: Moisture permeability exceeds 100 g / m 2

[0202] A value of △ or higher indicates a level that poses no practical problem and is judged to be good.

[0203] (Resistance to internal impact)

[0204] The obtained liquid crystal sealant was formed into a 24 mm × 24 mm square frame-shaped seal pattern (cross-sectional area 2500 μm) with a line width of 0.5 mm on a 40 mm × 45 mm glass substrate (RT-DM88-PIN, manufactured by EHC) on which a transparent electrode and an alignment film were previously formed. 2 A 38 mm x 38 mm square dummy seal pattern with a line width of 1 mm was formed around the dummy seal pattern using liquid crystal sealant. Liquid crystal (MLC-3007; manufactured by Merck) droplets (2.0 μl) were then added to the frame of the frame-shaped seal pattern.

[0205] Next, the paired glass substrates were bonded together under reduced pressure in a manner perpendicular to the glass substrates on which the frame-shaped seal pattern and the dummy seal pattern were formed, and then exposed to the atmosphere. The two bonded glass substrates were then kept in a light-shielding box for 1 minute and then irradiated with 3000 mJ / cm2 The sealant was then exposed to light containing visible light (wavelength 370 nm to 450 nm) and heated at 120°C for 1 hour to cure the sealant, thereby obtaining a test piece. The interface between the sealant and the liquid crystal was then observed using a polarizing microscope and evaluated according to the following criteria. The results are shown in Table 1.

[0206] ◎: The penetration of the liquid crystal material into the liquid crystal sealant (cured product) in the width direction (sealing path) is 0.1 mm or less

[0207] ○: Sealing path exceeds 0.1 mm and is less than 0.3 mm

[0208] △: Sealing path exceeds 0.3 mm and is less than 0.5 mm

[0209] ×: Sealing path exceeds 0.5 mm

[0210] (Descriptive)

[0211] The obtained liquid crystal sealant was filled into a 10cc syringe, degassed, and then filled into a dispenser (dispenser; manufactured by Musashi High-Tech Co., Ltd.). This dispenser was used to apply the sealant onto a glass substrate at a speed of 4 cm / s. The drawing properties (applicability) were evaluated according to the following criteria.

[0212] ○: No thread breakage or thread thinning

[0213] △: No thread breakage, but at least one thread thinning area

[0214] ×: There is one or more disconnected parts

[0215] [Table 1]

[0216]

[0217] As shown in Table 1, liquid crystal sealants containing a cyclopolymerizable compound represented by the general formula (1) (curable compound (A-1)) exhibit excellent internal impact resistance and drawing properties. Furthermore, the resulting sealing materials exhibit high adhesive strength and low moisture permeability (Examples 1 to 9). The polymer structure of the cyclopolymerizable compound makes it possible to achieve both high adhesive strength and low moisture permeability, a previously difficult balance.

[0218] In contrast, when curable compounds (A-3) and (A-4) having structures different from the general formula (1) were used, the results of both adhesive strength and low moisture permeability were poor (Comparative Examples 1 and 2).

[0219] Furthermore, in the examples, when the amount of the cyclopolymerizable compound relative to the total amount of filler was 3% by mass or more and 300% by mass or less, the internal impact resistance was particularly improved (Examples 1 to 7). It is believed that the viscosity of the liquid crystal sealant is within an appropriate range, making it difficult for liquid crystals to enter the frame-shaped seal pattern during lamination in a vacuum environment.

[0220] This application claims the benefit of priority based on Japanese Patent Application No. 2023-034812, filed on March 7, 2023. All contents described in that application specification are incorporated herein by reference.

[0221] Industrial applicability

[0222] According to the present invention, a liquid crystal sealant capable of producing a sealing material having adhesive strength and low moisture permeability, a liquid crystal display panel using the same, and a method for manufacturing the same are provided. Therefore, the present invention is very useful in the field of manufacturing liquid crystal display panels.

Claims

1. A liquid crystal sealant comprising a curable compound and a curing agent, The curable compound includes a cyclopolymerizable compound represented by the following general formula (1): [Chemistry 1] In general formula (1), R 1 represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, R 2 and R 3 each independently represents a hydrocarbon group having 1 to 4 carbon atoms, X represents a single bond, -O-, -S- or NR 4 ,in, R 4 It is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms.

2. The liquid crystal sealant according to claim 1, wherein The amount of the cyclopolymerizable compound is 1% by mass or more and 30% by mass or less relative to the total amount of the curable compound.

3. The liquid crystal sealant according to claim 1, further comprising a filler, The amount of the cyclopolymerizable compound is 3% by mass or more and 300% by mass or less relative to the total amount of the filler. 4 . The liquid crystal sealant according to claim 3 , wherein The filler comprises core-shell type microparticles. The liquid crystal sealant according to claim 1 , wherein The curable compound further includes an epoxy compound having an epoxy group, The curing agent includes at least one thermal curing agent selected from the group consisting of dihydrazide-based thermal latent curing agents, imidazole-based thermal latent curing agents, amine adduct-based thermal latent curing agents, and polyamine-based thermal latent curing agents. The liquid crystal sealant according to claim 1 , further comprising a silane coupling agent. 7 . The liquid crystal sealant according to claim 1 , wherein The curing agent includes at least one photopolymerization initiator selected from the group consisting of oxime ester photopolymerization initiators, thioxanthone photopolymerization initiators, and anthraquinone photopolymerization initiators. The liquid crystal sealant according to claim 1 , wherein Coated at a thickness of 100 μm and irradiated at 3000 mJ / cm 2 The moisture permeability of the cured product when heated at 120°C for 1 hour using light calibrated by a 365 nm wavelength sensor is 80 g / m 2 the following. 9 . The liquid crystal sealant according to claim 1 , wherein The sealing path measured by the following method is less than 0.5 mm, Method for determining sealing path: (i) forming a frame-shaped seal pattern with a line width of 0.5 mm and a size of 24 mm×24 mm on a glass substrate with an alignment film using the liquid crystal sealant; (ii) forming a dummy seal pattern of 38 mm×38 mm using the liquid crystal sealant so as to surround the frame-shaped seal pattern; (iii) dropping liquid crystal into the frame-shaped seal pattern; (iv) laminating the glass substrate with the alignment film and a counter substrate under reduced pressure so as to sandwich the frame-shaped seal pattern, and releasing the substrate to the atmosphere to obtain a laminate; (v) The laminate was kept in a light shielding box for 1 minute and irradiated with 3000 mJ / cm 2 Light with a wavelength of 370 nm to 450 nm; (vi) heating the laminate at 120° C. for 1 hour to cure the liquid crystal sealant; (vii) The boundary between the cured liquid crystal sealing compound and the liquid crystal is confirmed with a polarizing microscope, and the length of the liquid crystal that has entered in the width direction of the cured liquid crystal sealing compound is defined as a sealing path.

10. A liquid crystal display panel comprising: a pair of substrates; a liquid crystal layer sandwiched between the pair of substrates; and A frame-shaped sealing material is disposed between the pair of substrates and is used to seal the liquid crystal layer. The said sealing material is the hardened|cured material of the liquid crystal sealing agent in any one of Claims 1 to 9.

11. A method for manufacturing a liquid crystal display panel, comprising: A process of preparing a pair of substrates; a step of applying the liquid crystal sealant according to any one of claims 1 to 9 on one of the substrates to form a frame-shaped seal pattern; a step of applying a dummy sealant on the outer side of the frame-shaped seal pattern to form a dummy seal pattern; A step of dropping a liquid crystal material onto the inner side of the frame-shaped seal pattern and / or onto another substrate while the frame-shaped seal pattern and the dummy seal pattern are in an uncured state; a step of overlapping the pair of substrates with the liquid crystal material interposed therebetween under a reduced pressure environment; and a step of curing the frame-shaped seal pattern and the dummy seal pattern.

12. The method for manufacturing a liquid crystal display panel according to claim 11, wherein: The dummy sealant in the step of forming the dummy seal pattern is the liquid crystal sealant according to any one of claims 1 to 9.

13. The method for manufacturing a liquid crystal display panel according to claim 12, wherein: In the step of curing the frame-shaped seal pattern and the dummy seal pattern, light is irradiated.

14. The method for manufacturing a liquid crystal display panel according to claim 13, wherein: The light includes wavelengths in the visible light region.

15. The method for manufacturing a liquid crystal display panel according to claim 13, wherein: In the step of curing the frame-shaped seal pattern and the dummy seal pattern, heating is further performed.

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