Liquid crystal sealant, manufacturing method of liquid crystal display panel and liquid crystal display panel

Abstract

The liquid crystal sealant of the present invention comprises a curing compound (A), a thermosetting agent (B) and / or a photopolymerization initiator (C), and aluminum oxide (D) with an α-oxidation rate of less than 80%.

Description

Technical Field

[0001] This invention relates to a liquid crystal sealant, a method for manufacturing a liquid crystal display panel, and a liquid crystal display panel. Prior Technology

[0002] A liquid crystal display panel typically has a pair of substrates, a frame-shaped sealing member disposed between them, and liquid crystal material sealed within an area surrounded by the sealing member. This type of liquid crystal display panel is manufactured by a liquid crystal dispensing process.

[0003] In the liquid crystal deposition process, firstly, a rectangular sealing pattern is formed on one of a pair of substrates using a dispensing method. Then, while the sealant is not yet hardened, liquid crystal material is deposited into the sealing frame of the other substrate. The two substrates are then overlapped under vacuum, and the sealed area is temporarily hardened by irradiating it with ultraviolet light or other light. Afterward, heating is applied for final hardening, thereby producing a liquid crystal display panel.

[0004] In recent years, with the trend towards narrower bezels in LCD panels, there is also a demand for narrower linewidths in sealing components. Therefore, the requirements for sealing components are: even with narrower bezels, they must maintain the same or better adhesion and moisture resistance to the substrate as before, i.e., a high degree of balance between adhesion strength and moisture resistance.

[0005] As a method to improve the moisture resistance of sealants, methods for formulating inorganic fillers such as talc or alumina have been studied. For example, Patent Document 1 discloses a sealant for liquid crystal display elements, which includes a curable resin, a free radical polymerization initiator and / or a thermosetting agent, and alumina, wherein the content of alumina is more than 20 parts by mass relative to 100 parts by mass of the curable resin (A). Furthermore, Patent Document 2 discloses a sealant for liquid crystal display elements, which includes a curable resin, a free radical polymerization initiator or a thermosetting agent, and alumina or talc with an aspect ratio of 2 or more, wherein the content of alumina or talc is 85% by mass or more. [Existing Technical Documents] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2016-218447 [Patent Document 2] Japanese Patent Application Publication No. 2013-214056 Summary of the Invention

[0007] [The problem that the invention aims to solve]

[0008] As mentioned above, the moisture resistance of sealing components can be improved by incorporating inorganic fillers such as talc or alumina. However, the flexibility of the sealing component is compromised by incorporating inorganic fillers, which can easily lead to a decrease in adhesive strength. As mentioned above, there is usually a trade-off between adhesive strength and moisture resistance, and it is difficult to achieve both simultaneously in previous sealants.

[0009] The present invention was made in view of the above circumstances, and aims to provide a liquid crystal sealant, a method for manufacturing a liquid crystal display panel using the same, and a liquid crystal display panel, wherein the liquid crystal sealant can form a sealing member having high moisture resistance and high adhesion strength to the substrate. [Methods for solving problems]

[0010] [1] A liquid crystal sealant comprising a curing compound (A), a thermosetting agent (B) and / or a photopolymerization initiator (C), and aluminum oxide (D) with an α-oxidation rate of less than 80%. [2] The liquid crystal sealant as described in [1], wherein the average particle size of the alumina (D) is 0.01 μm to 3 μm. [3] The liquid crystal sealant as described in [1] or [2], wherein the content of aluminum oxide (D) is 1 to 20 parts by mass relative to 100 parts by mass of the curing compound (A). [4] The liquid crystal sealant as described in any one of [1] to [3], wherein the aspect ratio of the alumina (D) is 2.0 or less. [5] The liquid crystal sealant as described in any one of [1] to [4], wherein the aluminum oxide (D) is in particulate form. [6] The liquid crystal sealant as described in any one of [1] to [5] comprises a thermosetting compound (A1) having an intramolecular epoxy group as the curing compound (A), and the thermosetting agent (B). [7] The liquid crystal sealant as described in [6], wherein the content of the thermosetting compound (Al) is 5 to 20 parts by mass relative to 100 parts by mass of the curing compound (A). [8] The liquid crystal sealant as described in [6] or [7], wherein the content of the thermosetting agent (B) is 10 parts by mass or more relative to 100 parts by mass of the curing compound (A). [9] The liquid crystal sealant as described in any one of [6] to [8], wherein the thermosetting agent (B) comprises at least one selected from the group consisting of diacetylhydrazine-based thermosetting agents, imidazole-based thermosetting agents, amine adduct-based thermosetting agents and polyamine-based thermosetting agents.

[10] The liquid crystal sealant as described in any one of [6] to [9] further comprises a compound (A2) having an intramolecular ethylene unsaturated double bond as the curing compound (A), and the photopolymerization initiator (C), and the content ratio (A1 / A2) of the thermocuring compound (A1) to the compound (A2) is 30 / 70 to 50 / 50 (mass ratio).

[11] The liquid crystal sealant as described in any one of [6] to

[10] further comprises a portion of epoxy (meth)acrylate (A3) as the curing compound (A).

[12] The liquid crystal sealant as described in any one of [1] to

[10] , wherein the photopolymerization initiator (C) comprises at least one selected from the group consisting of oxime ester compounds, thioxanone compounds, and anthraquinone compounds.

[13] The liquid crystal sealant as described in any one of [1] to

[11] further comprises a coupling agent.

[14] The liquid crystal sealant as described in any one of [1] to

[13] is a liquid crystal sealant for liquid crystal droplet process.

[15] A method for manufacturing a liquid crystal display panel includes: forming a sealing pattern of a liquid crystal sealant as described in any one of [1] to

[14] on one of the substrates; applying liquid crystal to the area of ​​the sealing pattern or to another substrate paired with one of the substrates while the sealing pattern is not hardened; overlapping one of the substrates and the other substrate through the sealing pattern; and The step of hardening the sealing pattern.

[16] The method for manufacturing a liquid crystal display panel as described in

[15] , wherein the step of hardening the sealing pattern includes the step of irradiating the sealing pattern with light to harden the sealing pattern.

[17] The method for manufacturing a liquid crystal display panel as described in

[16] , wherein the light irradiating the sealing pattern includes light in the visible light region.

[18] The method of manufacturing a liquid crystal display panel as described in

[16] or

[17] further includes the step of hardening the sealing pattern by heating the light-irradiated sealing pattern to harden it.

[19] A liquid crystal display panel includes: a pair of substrates; a frame-shaped sealing member disposed between the pair of substrates; and a liquid crystal layer filling the space between the pair of substrates surrounded by the sealing member, wherein the sealing member comprises a hardened liquid crystal sealant as described in any one of [1] to

[13] . [The effects of the invention]

[0011] According to the liquid crystal sealant of the present invention, a sealing member with high moisture resistance and high adhesion strength to the substrate can be formed. Simple Explanation of the Diagram

[0012] none Implementation

[0013] In this specification, the numerical range indicated by "~" refers to the range of values ​​before and after "~" as both the lower and upper limits. Within the numerical ranges described in this specification, the upper or lower limit value described in a particular numerical range may be replaced by the upper or lower limit value of other numerical ranges described in different stages.

[0014] As mentioned above, alumina is sometimes added to liquid crystal sealants to impart moisture resistance or strength to the sealing components. Alumina can have various crystalline phases, such as α, β, θ, and γ, depending on the manufacturing conditions, including sintering temperature. Among these, alumina with the highest sintering temperature and the α crystalline phase exhibits high heat resistance and chemical stability, and is therefore widely used. However, it is also a factor that reduces the adhesion strength to the substrate.

[0015] In contrast, the inventors have discovered that alumina with an α-oxidation rate below a certain level can improve the moisture resistance of the sealing component without reducing the adhesion strength to the substrate; on the contrary, it can improve the adhesion strength.

[0016] The reason is not clear, but it can be speculated as follows. Compared with alumina with a high α-oxidation rate, alumina (D) with a low α-oxidation rate has a large number of hydroxyl groups that easily align around aluminum atoms, resulting in a large number of hydroxyl groups on the surface. This leads to the formation of hydrogen bonds between the hydroxyl groups of alumina (D) and the hydroxyl groups on the substrate, or between the hydroxyl groups of alumina (D) and the epoxy groups or hydroxyl groups (especially epoxy groups) of the curing compound (A), thus improving the adhesion strength to the substrate. The structure of the liquid crystal sealant of the present invention will be specifically described below.

[0017] 1. Liquid crystal sealant The liquid crystal sealant of the present invention comprises a curing compound (A), a thermosetting agent (B) for curing the curing compound (A), and / or a photopolymerization initiator (C), and alumina (D) with an α-oxidation rate of 80% or less, and may further comprise other components such as inorganic fillers (E) if necessary. The curing compound may be any one of monomers, oligomers, or polymers.

[0018] 1-1. Hardening compound (A) 1-1-1. Thermosetting compounds with intramolecular epoxy groups (A1) The liquid crystal sealant may comprise a thermosetting compound (A1) having intramolecular epoxy groups as a curing compound (A). Preferably, the thermosetting compound (A1) contains two or more intramolecular epoxy groups. Furthermore, in this specification, the thermosetting compound (A1) does not contain any epoxy (meth)acrylate. Additionally, the thermosetting compound (A1) is preferably used in conjunction with the thermosetting agent (B) described later.

[0019] The thermosetting compound (A1) can be any of a monomer, oligomer, or polymer. The thermosetting compound (A1) can further reduce the moisture permeability of the cured material and improve the display characteristics of the obtained liquid crystal display panel.

[0020] The weight-average molecular weight of the thermosetting compound (A1) is preferably 300 to 10,000, more preferably 300 to 5,000. The weight-average molecular weight of the thermosetting compound (A1) is determined by gel permeation chromatography (GPC) based on polystyrene conversion.

[0021] The thermosetting compound (A1) is preferably a compound having an aromatic ring. Examples of epoxy compounds having an aromatic ring include aromatic polyglycidyl ether compounds obtained by reacting aromatic diols, represented by bisphenol A, bisphenol S, bisphenol E, bisphenol F, bisphenol AD, etc., or diols obtained by modifying these aromatic diols with ethylene glycol, propylene glycol, alkyl glycol, etc., with epichlorohydrin; phenolic varnish-type polyglycidyl ether compounds obtained by reacting polyphenols, represented by phenolic varnish resins derived from phenol or cresol and formaldehyde, polyolefin phenol, or copolymers thereof, with epichlorohydrin; and glycidyl ether compounds of xylene-methylphenol resin, etc. Preferably, the epoxy compound is a cresol-phenolic varnish-type epoxy compound, a phenolic phenolic varnish-type epoxy compound, a bisphenol A-type epoxy compound, a bisphenol F-type epoxy compound, a triphenol-methane-type epoxy compound, a triphenol-ethane-type epoxy compound, a triphenol-type epoxy compound, a dicyclopentadiene-type epoxy compound, a diphenyl ether-type epoxy compound, or a biphenyl-type epoxy compound. The liquid crystal sealant may contain only one type of epoxy compound or may contain two or more types. Preferably, it is a bisphenol A-type epoxy compound with a bisphenol A backbone within the molecule. The thermosetting compound (Al) may be liquid or solid.

[0022] The content of the thermosetting compound (A1) is preferably 2 to 40 parts by mass relative to 100 parts by mass of the curing compound (A). If the content of the thermosetting compound (A1) is 2 parts by mass or more, the adhesion strength to the substrate is more easily improved. This is because the thermosetting compound (A1) with epoxy groups has epoxy or hydroxyl groups (especially epoxy groups), which readily form hydrogen bonds with the hydroxyl groups on the surface of the alumina (D), thereby easily improving the adhesion strength of the cured product. If the content of the thermosetting compound (A1) is 40 parts by mass or less, the flexibility of the cured product is less likely to be damaged. From the same point of view, the content of the thermosetting compound (A1) is more preferably 5 to 20 parts by mass relative to 100 parts by mass of the curing compound (A), and more preferably 10 to 20 parts by mass.

[0023] 1-1-2. Compounds containing intramolecular ethylene unsaturated double bonds (A2) The liquid crystal sealant may also contain a compound (A2) having an intramolecular vinyl unsaturated double bond as a curing compound (A). Furthermore, in this specification, the compound (A2) having an intramolecular vinyl unsaturated double bond does not contain any epoxy (meth)acrylate. Additionally, the compound having an intramolecular vinyl unsaturated double bond is preferably used in conjunction with the photopolymerization initiator (C) described later.

[0024] The compound (A2) having an intramolecular vinyl unsaturated double bond can be a monomer, oligomer, or polymer. Examples of compounds having an intramolecular vinyl unsaturated double bond include compounds having an intramolecular (meth)acrylamide group. Each molecule of this compound having a (meth)acrylamide group may contain one or more (meth)acrylamide groups.

[0025] Furthermore, in this specification, "(meth)acrylate" refers to acrylate or methacrylate, "(meth)acryl" refers to acrylonitrile or methacryl, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid, and "(meth)acrylic resin" refers to acrylic resin or methacrylic resin.

[0026] Examples of curable compounds containing one (meth)acrylic group within one molecule include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and 2-hydroxyethyl methacrylate.

[0027] Examples of curable compounds having two or more (meth)acrylic groups within 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 mol of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol; and di(meth)acrylates derived from 1 mol of bisphenol A or bisphenol F by adding 2 mol of bisphenol A or bisphenol F. Di(meth)acrylates (bisphenol A type epoxy(meth)acrylates or bisphenol F type epoxy(meth)acrylates) of diols obtained from ethylene oxide or propylene oxide; di(meth)acrylates or tri(meth)acrylates of polyols obtained by adding 2 or 3 mol of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane; diols obtained by adding 4 or more mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A. Di(meth)acrylate; tri(2-hydroxyethyl) isocyanurate tri(meth)acrylate; trimethylolpropane tri(meth)acrylate or oligomer thereof; pentaerythritol tri(meth)acrylate or oligomer thereof; dipentaerythritol poly(meth)acrylate; tri(acryloxyethyl) isocyanurate; caprolactone-modified tri(acryloxyethyl) isocyanurate; caprolactone-modified tri(methacryloxyethyl) isocyanurate; alkyl Poly(meth)acrylates modified with pentaerythritol; poly(meth)acrylates modified with caprolactone; neopentyl glycol di(meth)acrylates with hydroxytrimethylacetic acid; neopentyl glycol di(meth)acrylates modified with caprolactone; ethylene oxide modified phosphate (meth)acrylates; ethylene oxide modified alkylated phosphate (meth)acrylates; and oligomeric (meth)acrylates of neopentyl glycol, trimethylolpropane, and pentaerythritol, etc. Preferably, these are di(meth)acrylates of diols derived from the addition of 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A or bisphenol F (bisphenol A type epoxy (meth)acrylates or bisphenol F type epoxy (meth)acrylates).

[0028] The weight-average molecular weight of the compound (A2) having an intramolecular vinyl unsaturated double bond, as determined by gel permeation chromatography (GPC), is, for example, 200 to 10,000, preferably 200 to 5,000.

[0029] The content of compound (A2), which has an intramolecular vinyl unsaturated double bond, is preferably 10 to 50 parts by mass, more preferably 15 to 40 parts by mass, and even more preferably 20 to 35 parts by mass, relative to 100 parts by mass of curing compound (A). If the content of compound (A2) is 20 parts by mass or more, compound (A2) is more likely to be fully cured during temporary curing using photocuring, thus making it easier to suppress liquid crystal contamination. If the content of compound (A2) is 30 parts by mass or less, the adhesion strength to the substrate is less likely to be damaged.

[0030] 1-1-3. Partially epoxy (meth)acrylates (A3) The liquid crystal sealant may also contain a portion of epoxy (meth)acrylate (A3) as a curing compound (A). The portion of epoxy (meth)acrylate (A3) can improve the adhesion of the cured liquid crystal sealant to the substrate and improve the compatibility of the thermosetting compound (A1) with epoxy groups with compounds (A2) having intramolecular vinyl unsaturated double bonds.

[0031] Partially epoxy (meth)acrylate (A3) is a partially (meth)acrylic acid modified epoxy resin obtained by modifying at least one epoxy group of a difunctional or higher epoxy resin with a (meth)acrylic acid group. Partially epoxy (meth)acrylate (A) can be obtained, for example, by reacting a difunctional or higher epoxy resin with (meth)acrylic acid in the presence of an alkaline catalyst.

[0032] The epoxy resin used as a raw material for partial epoxy (meth)acrylate (A3) can be any epoxy resin having two or more epoxy groups within its molecule. Examples of such epoxy resins include bisphenol-type epoxy resins such as bisphenol A, bisphenol F, 2,2'-diallylbisphenol A, bisphenol AD, and hydrogenated bisphenol; phenolic varnish-type epoxy resins such as phenolic varnish-type, cresolic varnish-type, biphenyl varnish-type, and triphenolic varnish-type; biphenyl-type epoxy resins; and naphthalene-type epoxy resins. Among these, bisphenol-type epoxy resins such as bisphenol A or bisphenol F are preferred in terms of low crystallinity and high coating stability.

[0033] Furthermore, the epoxy resin can be trifunctional or tetrafunctional, or an epoxy resin having four or more epoxy groups. Among these, from the viewpoint of appropriately adjusting the crosslinking density to appropriately improve the adhesion strength of the cured material to the substrate, a difunctional epoxy resin is preferred.

[0034] Regarding the epoxy (meth)acrylate (A3), the ratio of the mole number of (meth)acrylic groups to the mole number of epoxy groups is preferably 1 or more, and more preferably 2 or more. By increasing the mole number ratio of (meth)acrylic groups, liquid crystal contamination caused by the leaching of sealant into the liquid crystal is easily suppressed.

[0035] The weight-average molecular weight of some epoxy (meth)acrylates (A3), as determined by gel permeation chromatography (GPC), is preferably 300-500.

[0036] Relative to 100 parts by weight of the curing compound (A), the content of a portion of epoxy (meth)acrylate (A3) is preferably 20 to 80 parts by weight, more preferably 30 to 70 parts by weight, and even more preferably 45 to 65 parts by weight. If the content of a portion of epoxy (meth)acrylate (A3) is 20 parts by weight or more, the adhesion strength of the cured material is more easily improved while simultaneously enhancing the compatibility with the thermosetting compound (A1) or the compound (A2). If the content of a portion of epoxy (meth)acrylate (A3) is 80 parts by weight or less, the flexibility of the cured material is less likely to be compromised.

[0037] 1-1-4. Common Items The curing compound (A) preferably includes at least one of the following: a thermosetting compound (A1), a compound having an intramolecular vinyl unsaturated double bond (A2), and a portion of an epoxy (meth)acrylate (A3); and more preferably includes all of them from the viewpoint of balancing photocuring and thermocuring.

[0038] Furthermore, the content ratio (A1 / A2) of the thermosetting compound (A1) and the compound (A2) having intramolecular ethylene unsaturated double bonds can be set according to the desired performance. For example, from the viewpoint of further improving the adhesion strength to the substrate, it is preferable to have a higher proportion of thermosetting compound (A1), and the A1 / A2 ratio is preferably 30 / 70 to 50 / 50 (mass ratio), more preferably 40 / 60 to 50 / 50 (mass ratio).

[0039] 1-2. Thermosetting agent (B) The sealant contains a thermosetting agent (B) for curing the thermosetting compound (A1).

[0040] Thermosetting agent (B) is preferably a latent thermosetting agent. A latent thermosetting agent refers to a compound that does not cure the thermosetting compound (A1) or a portion of the epoxy (meth)acrylate (A3) under normal storage conditions (room temperature, visible light, etc.), but will cure these compounds upon heating. Thermosetting agent (B) is preferably a curing agent capable of curing epoxy compounds (hereinafter also referred to as "epoxy curing agent").

[0041] From the viewpoint of improving the viscosity stability of photothermal curing resin components without compromising the moisture resistance of the cured material, the melting point of epoxy curing agent is preferably 50℃~250℃, more preferably 100℃~200℃, and even more preferably 150℃~200℃.

[0042] Examples of epoxy curing agents include diacetylhydrazine-based thermal latent curing agents, imidazole-based thermal latent curing agents, dicyandiamine-based thermal latent curing agents, amine adduct-based thermal latent curing agents, and polyamine-based thermal latent curing agents. Among these, diacetylhydrazine-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 are preferred. From the viewpoint of further improving the display properties, imidazole-based thermal latent curing agents, amine adduct-based thermal latent curing agents, and polyamine-based thermal latent curing agents are even more preferred, and amine adduct-based thermal latent curing agents and polyamine-based thermal latent curing agents are even more preferred.

[0043] Examples of diacetic acid diacetic acid latent curing agents include diacetic acid diacetic acid (melting point 181℃), 1,3-bis(hydrazylcarbonylethyl)-5-isopropylhydantoin (melting point 120℃), 7,11-octadecadiene-1,18-dicarbonyl acetic acid (melting point 160℃), dodecanoic acid diacetic acid (melting point 190℃), and sebacate diacetic acid (melting point 189℃).

[0044] Examples of imidazole-based heat-latent curing agents include 2,4-diamino-6-[2'-ethylimidazolyl-(1')]-ethyltriazine (melting point 215℃~225℃) and 2-phenylimidazolium (melting point 137℃~147℃).

[0045] Examples of dicyandiamine-based heat-latent curing agents include dicyandiamine (melting point 209°C).

[0046] Amine adduct-based thermal latent curing agents are thermal latent curing agents comprising an addition compound obtained by reacting a catalytically active amine compound with any compound. Examples of amine adduct-based heat-latent curing agents include Amicure PN-40 (melting point 110°C), Amicure PN-50 (melting point 120°C), Amicure PN-23 (melting point 100°C), Amicure PN-31 (melting point 115°C), Amicure PN-H (melting point 115°C), Amicure MY-24 (melting point 120°C), and Amicure MY-H (melting point 131°C) manufactured by Ajinomoto Fine-Techno.

[0047] Polyamine-based latent heat curing agents are latent heat curing agents with polymer structures obtained by reacting amines with epoxy resins. Examples of such latent heat curing agents include Adeka Hardener EH4339S (softening point 120℃~130℃) and Adeka Hardener EH4357S (softening point 73℃~83℃) manufactured by Adeka Corporation.

[0048] The content of thermosetting agent (B) is preferably 10 parts by mass or more, and more preferably 15 to 30 parts by mass, relative to 100 parts by mass of curing compound (A). If the content of thermosetting agent (B) is 10 parts by mass or more, the curing properties of thermosetting compound (A1) are easily improved. If the content of thermosetting agent (B) is 30 parts by mass or less, liquid crystal contamination caused by the dissolution of thermosetting agent (B) into the liquid crystal is more easily suppressed.

[0049] In addition, the content of thermosetting agent (B) is preferably 50 to 300 parts by mass, and more preferably 100 to 200 parts by mass, relative to 100 parts by mass of thermosetting compound (A1).

[0050] 1-3. Photopolymerization initiator (C) The liquid crystal sealant may also contain a photopolymerization initiator (C) for initiating the hardening (polymerization) of a compound (A2) having an intramolecular ethylene unsaturated double bond.

[0051] There are no particular limitations on the photopolymerization initiator (C), which is a compound that can initiate the hardening (polymerization) of the compound. For example, the photopolymerization initiator (C) can be a free radical polymerization initiator, a self-decomposing photopolymerization initiator, or a dehydrogenating photopolymerization initiator.

[0052] Examples of self-degrading photopolymerization initiators include phenylalkyl ketone compounds, phosphine oxide compounds, dicthene compounds, acetophenone compounds, benzoic acid ester compounds, benzoyl ether compounds, and oxime ester compounds. Examples of phenylalkyl ketone compounds include benzodiazepine dimethyl ketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one (IRGACURE 651 manufactured by BASF), α-aminophenylalkyl ketones such as 2-methyl-2-morpholino(4-thiomethylphenyl)propane-1-one (IRGACURE 907 manufactured by BASF), and α-hydroxyphenylalkyl ketones such as 1-hydroxy-cyclohexyl-phenyl-one (IRGACURE 184 manufactured by BASF). Examples of the phosphine oxide compounds include 2,4,6-trimethylbenzodiphenylphosphine oxide, etc. Examples of the titanium cadmium compounds include bis(n5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrolo-1-yl)-phenyl)titanium, etc. Examples of the acetophenone compounds include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, benzodiazepine dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)one, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propane-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, etc. Examples of the benzoic acid ester compounds include methyl benzoate, etc. 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-benzoyl oxime)] (IRGACURE OXE01 manufactured by BASF) and acetone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetylgoxymeta) (IRGACURE OXE02 manufactured by BASF), etc.

[0053] Examples of dehydrogenated photopolymerization initiators include benzophenone-based compounds, thioxanthone-based compounds, anthraquinone-based compounds, and benzodiazepine-based compounds. Examples of benzophenone-based compounds include benzophenone, methyl o-benzoylbenzoate-4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra(tert-butyl carbonyl peroxide)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-isopropylthioxanthone (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 Corporation), etc. Examples of the anthraquinone compounds include 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-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 Pure Chemical Industries Co., Ltd.).

[0054] The absorption wavelength of the photopolymerization initiator (C) is not particularly limited; for example, it can be set as a photopolymerization initiator that absorbs light with a wavelength of 360 nm or higher. More preferably, it absorbs light in the visible light region, and even more preferably, it absorbs light with a wavelength of 360 nm to 780 nm. Most preferably, it absorbs light with a wavelength of 360 nm to 430 nm.

[0055] Examples of photopolymerization initiators that absorb light with wavelengths above 360 ​​nm include phenylalkyl ketone compounds, phosphonium oxyacetate compounds, diacetic acid compounds, oxime ester compounds, thioxanthone compounds, and anthraquinone compounds. Among these, oxime ester compounds, thioxanthone compounds, and anthraquinone compounds are preferred, and oxime ester compounds are even more preferred.

[0056] The molecular weight of the photopolymerization initiator (C) can be set, for example, to be 200 to 5000. If the molecular weight of the photopolymerization initiator (C) is 200 or higher, it is less likely to dissolve into the liquid crystal. On the other hand, if the molecular weight of the photopolymerization initiator (C) is 5000 or lower, its compatibility with various curing compounds (A) is improved, and the curing properties of the sealant become easier to achieve. The molecular weight of the photopolymerization initiator (C) is more preferably 230 to 3000, and even more preferably 230 to 1500.

[0057] The molecular weight of the photopolymerization initiator (C) can be determined as the "relative molecular mass" of the molecular structure of the main peak detected by high performance liquid chromatography (HPLC).

[0058] Specifically, a sample solution is prepared by dissolving the photopolymerization initiator (C) in tetrahydrofuran (THF) and then 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 area of ​​all peaks) is then calculated to confirm the presence of a main peak. The main peak is the peak with the highest intensity (highest peak height) among all peaks detected at a characteristic detection wavelength (e.g., 400 nm for thioxanthone compounds). The relative molecular mass corresponding to the peak apex of the detected main peak can be determined by liquid chromatography-mass spectrometry (LC / MS).

[0059] The content of photopolymerization initiator (C) is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of the photocurable compound (e.g., the total of a compound with an intramolecularly ethylene-unsaturated double bond (A2) and a portion of epoxy (meth)acrylate (A3)). More preferably, it is 0.1 to 5 parts by mass, and even more preferably, it is 0.1 to 3 parts by mass. If the content is 0.01 parts by mass or more, the photocurability of the sealant is easily improved. If it is 10 parts by mass or less, liquid crystal contamination caused by the dissolution of photopolymerization initiator (C) into the liquid crystal is more easily suppressed.

[0060] 1-4. Alumina (D) The liquid crystal sealant contains aluminum oxide (D) with an α-saturation rate of 80% or less. As mentioned above, aluminum oxide (D) with a low α-saturation rate has a large number of hydroxyl groups on its surface. Therefore, hydrogen bonds are easily formed, especially between the hydroxyl groups of aluminum oxide (D) and the epoxy groups of the thermosetting compound (Al) or between the hydroxyl groups of aluminum oxide (D) and the hydroxyl groups on the substrate, which is considered to improve the adhesion strength to the substrate.

[0061] The α-sizing rate of alumina (D) is 80% or less, preferably 50% or less, and even more preferably 20% or less. If the α-sizing rate of alumina (D) is 50% or less, it is easier to improve the adhesion strength to the substrate. There is no particular limitation on the lower limit of the α-sizing rate; for example, from the viewpoint of easily forming uniform spherical shapes, it is 1%, preferably 4%. The α-sizing rate of alumina (D) can be adjusted by manufacturing conditions such as sintering temperature.

[0062] The α-oxidation rate of alumina (D) can be determined according to the following procedure. X-ray diffraction measurements were performed on powders prepared by mixing α-phase alumina powder AA-05 (manufactured by Sumitomo Chemical Co., Ltd.) and θ-phase alumina powder Taimicron™-100D (manufactured by Daming Chemical Co., Ltd.) in mass ratios of 0:10, 5:5, and 10:0. The integrated intensity of the peak value of the α-phase detected at 2θ=43° was calculated, and a calibration curve of mixing ratio versus integrated intensity was prepared. Secondly, the powder of alumina (D) was subjected to X-ray diffraction measurement, and the integrated intensity of the peak at 2θ=43° was calculated. The content of the α phase, i.e., the α-phase concentration (%), was determined by comparing it with the calibration curve. Furthermore, a JDX-3500 X-ray diffraction apparatus (manufactured by Nippon Eiichiro Co., Ltd.) can be used for X-ray diffraction.

[0063] The shape of the alumina (D) is not particularly limited as long as the α-oxidation rate meets the aforementioned range, and it can be any of the following: spherical, fragmented (plate-like), needle-like, etc. Among these, spherical alumina is preferred from the viewpoint of having a large surface area and easily improving the adhesion strength with the substrate.

[0064] There are no particular limitations on the aspect ratio of alumina (D), but it is preferably 2.0 or less, and more preferably 1.0 to 1.5. Alumina (D) with an aspect ratio of 2.0 or less has a large surface area and easily improves the adhesion strength to the substrate. In addition, when used in liquid crystal display panels, it is less likely to peel off due to stress concentration points, which can further suppress the reduction of adhesion strength.

[0065] The aspect ratio of alumina (D) is determined by selecting any 20 particles from an image obtained using a scanning electron microscope (SEM), measuring their major and minor axes, and calculating the average major and minor axes. The average major and minor axes can then be substituted into the following formula to calculate the aspect ratio. Aspect ratio = average major axis (μm) / average minor axis (μm)

[0066] There are no particular limitations on the average particle size of alumina (D), as long as it is within a range suitable for the cell spacing of the liquid crystal display panel. For example, the average particle size of alumina (D) can be 0.01 μm to 25 μm, preferably 0.01 μm to 3 μm, and even more preferably 0.1 μm to 2 μm. If the average particle size of alumina (D) is 0.01 μm or more, it is easier to improve the moisture resistance of the cured liquid crystal sealant. If the average particle size of alumina (D) is 3 μm or less, it is easier to suppress poor curing of compounds (A2) or some epoxy (meth)acrylates (A3) with intramolecular vinyl unsaturated double bonds caused by alumina (D) blocking or reflecting light during photocuring, which can further suppress liquid crystal contamination. The average particle size of alumina (D) can be measured using a Microtrac MT3300.

[0067] The content of alumina (D) is preferably 2 to 25 parts by mass, more preferably 5 to 20 parts by mass, and even more preferably 7 to 15 parts by mass, relative to 100 parts by mass of the curing compound (A). A higher content of alumina (D) makes it easier to further reduce the moisture permeability of the cured material. On the other hand, by avoiding excessive alumina (D) content, the flexibility of the cured material is less likely to be damaged, and consequently, its strength is also less likely to be compromised. Furthermore, it can further suppress poor photocuring caused by light reflection due to alumina (D), thus further reducing liquid crystal contamination.

[0068] 1-5. Inorganic fillers (E) The liquid crystal sealant may also contain other inorganic fillers (E) besides alumina. In addition to imparting a specified hardness or linear expansion to the cured material, the inorganic filler (E) can also inhibit the permeation of moisture through the interior of the cured material and further reduce the moisture permeability of the cured material.

[0069] Examples of inorganic fillers (E) include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, titanium nitride, and other than those mentioned above, aluminum oxide, 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.

[0070] The inorganic filler (E) can be in a fixed shape such as spherical, plate-like, or needle-like, or it can be an irregular shape. When the inorganic filler (E) is spherical, the average primary particle size is preferably 1.5 μm or less. Furthermore, the specific surface area of ​​the inorganic filler (E) is preferably 0.5 m² / g or more and 20 m² / g or less. The average primary particle size of the inorganic filler (E) can be determined by the laser diffraction method described in Japanese Industrial Standards (JIS) Z8825 (2013). The specific surface area of ​​the filler can be determined by the Brunauer-Emmett-Teller method (BET method) described in JIS Z8830 (2013).

[0071] The content of inorganic filler (E) is preferably 2 to 30 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 5 to 20 parts by mass, relative to 100 parts by mass of curing compound (A). A higher content of inorganic filler (E) makes it easier to further reduce the moisture permeability of the cured material, thereby further increasing its hardness. On the other hand, by avoiding excessive content of inorganic filler (E), the flexibility of the cured material is less likely to be compromised, and consequently, its strength is also less likely to be compromised.

[0072] 1-6. Other In addition to the aforementioned components, the liquid crystal sealant may also include thermal free radical polymerization initiators, organic microparticles, coupling agents such as silane coupling agents, ion traps, ion exchangers, leveling agents, pigments, dyes, sensitizers, plasticizers, and defoamers.

[0073] Examples of thermal free radical polymerization initiators include organic peroxides, azo compounds, benzoin derivatives, benzoin ethers, and acetophenone derivatives.

[0074] Organic microparticles can reduce residual stress during the application of liquid crystal sealants. For example, organic microparticles can be formulated into organic microparticles with an elastic core and shell, wherein the core comprises conjugated diene rubber and silicone rubber, and the shell comprises polymers such as (meth)acrylate, ethylene monomers and epoxy monomers to improve compatibility with other components.

[0075] Alternatively, coated particles may be used that have a core containing inorganic particles and a polymer layer covering the core, and have functional groups containing carbon-carbon double bonds on the surface. The functional groups containing carbon-carbon double bonds may be vinyl, allyl, acrylic, or methacrylate. In the example of the core particles, the same as those listed above as the inorganic filler (E) may be used; from the viewpoint of excellent thermal stability, silicon dioxide is preferred.

[0076] The content of organic microparticles is preferably 5 to 17 parts by mass relative to 100 parts by mass of liquid crystal sealant. If the content of organic microparticles is 5 parts by mass or more, the adhesion strength between the cured material and the substrate can be further improved. On the other hand, if the content of organic microparticles is 17 parts by mass or less, the amount of other components (such as curing compounds) is sufficiently high, which can further improve the strength of the cured material.

[0077] Examples of silane coupling agents include vinyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane.

[0078] The content of silane coupling agent is preferably 0.01 to 5 parts by weight relative to 100 parts by weight of liquid crystal sealant. If the content of silane coupling agent is 0.01 parts by weight or more, the adhesion strength between the cured material and the substrate can be further improved.

[0079] Liquid crystal sealants may also include spacers for adjusting the gaps between liquid crystal display panels.

[0080] Relative to 100 parts by weight of the liquid crystal sealant, the total amount of other components is preferably 0.1 to 50 parts by weight. If the total amount is less than 50 parts by weight, the viscosity of the sealant is less likely to increase excessively, and the coating stability of the sealant is less likely to be compromised.

[0081] 1-7. Properties of Sealants The viscosity of the liquid crystal sealant at 25°C and 2.5 rpm, measured by an E-type viscometer, is preferably 200 Pa·s to 450 Pa·s, more preferably 300 Pa·s to 400 Pa·s. If the viscosity is within this range, the sealant's spreadability using a dispenser becomes good.

[0082] 2. Liquid crystal display panel and its manufacturing method The liquid crystal display panel of the present invention includes: a pair of substrates (a display substrate and an opposing substrate); a frame-shaped sealing member disposed between the pair of substrates; and a liquid crystal layer filling the space between the pair of substrates surrounded by the sealing member.

[0083] Both the display substrate and the opposing substrate 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).

[0084] A matrix of thin-film transistors (TFTs), color filters, black matrices, etc., can be disposed on the surface of the display substrate or the opposing substrate. An alignment film is further disposed on the surface of the display substrate or the opposing substrate. The alignment film contains known organic or inorganic alignment agents.

[0085] The sealing member can be disposed between the display substrate or opposing substrates, preferably between the alignment films of the pair of substrates. The sealing member is a hardened form of the liquid crystal sealant.

[0086] The liquid crystal display panel is manufactured using the liquid crystal sealant of the present invention. While liquid crystal display panel manufacturing methods typically include liquid crystal dispensing and liquid crystal injection processes, the liquid crystal display panel of the present invention is preferably manufactured using the liquid crystal dispensing process.

[0087] The manufacturing method of a liquid crystal display panel using a liquid crystal dispensing process includes: 1) The step of forming a sealing pattern of the liquid crystal sealant on one of a pair of substrates; 2) The step of depositing liquid crystal onto the area surrounded by the sealing pattern on one substrate or onto another substrate while the sealing pattern is not hardened; 3) The step of overlapping one substrate and another substrate by means of a sealing pattern; and 4) Steps to harden the sealing pattern.

[0088] In step 1), the liquid crystal sealant can be coated on one of the substrates to form a sealing pattern. The sealing pattern can be disposed on the alignment film of one of the substrates, or on the outer periphery of the alignment film, preferably on the alignment film.

[0089] In step 2), the so-called uncured state of the sealing pattern refers to the state where the curing reaction of the liquid crystal sealant has not proceeded to the gelation point. Therefore, in step 2), in order to inhibit the dissolution of the liquid crystal sealant in the liquid crystal, the sealing pattern can also be subjected to light irradiation or heating to make it semi-cured. One substrate and the other substrate are respectively a display substrate or opposing substrates.

[0090] In step 4), curing by light irradiation and subsequent curing by heat can be performed. By performing curing by light irradiation, the liquid crystal sealant can be cured in a short time, thus suppressing dissolution in the liquid crystal. By combining curing by light irradiation and curing by heat, damage to the liquid crystal layer caused by light can be reduced compared to curing by light irradiation alone.

[0091] The irradiated light can be appropriately selected based on the type of photopolymerization initiator (C) in the sealant, preferably light in the visible light region, for example, light with a wavelength of 370 nm or higher and 450 nm or lower. This is because light of this wavelength causes relatively little damage to the liquid crystal material or driving electrode. Known light sources emitting ultraviolet or visible light can be used for irradiation. When irradiating with visible light, high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, xenon lamps, fluorescent lamps, etc., can be used.

[0092] The light irradiation energy need to be sufficient to cure the compound (A2) or a portion of the epoxy (meth)acrylate (A3). The curing time also depends on the composition of the liquid crystal sealant, but is, for example, around 10 minutes.

[0093] The curing temperature also depends on the composition of the liquid crystal sealant, but for example, it is 120°C and the curing time is about 2 hours. [Example]

[0094] The present invention will now be described in more detail through examples. However, the scope of the present invention is not limited to these examples, and modifications can be made without departing from the spirit of the invention.

[0095] 1. Preparation of materials 1-1. Hardening compound (A) 1-1-1. Thermosetting compounds with intramolecular epoxy groups (A1) • Bisphenol A type epoxy resin (manufactured by ADEKA, EP-4000S, epoxy equivalent 260 g / eq)

[0096] 1-1-2. Compounds containing intramolecular ethylene unsaturated double bonds (A2) • Bisphenol A type acrylic resin (manufactured by Daicel Allnex, EBECRYL 3700, weight average molecular weight 485)

[0097] 1-1-3. Partially epoxy (meth)acrylates (A3) • Acrylic / epoxy blended resin (manufactured by Neo Chemical, BFEA-50, epoxy equivalent 470 g / eq)

[0098] 1-2. Thermosetting agent (B) • Amine adduct-based heat latent curing agent (manufactured by Ajinomoto Fine Chemicals Co., Ltd., Amicure PN-50 ("Amicure" is a registered trademark of Ajinomoto Co., Ltd.))

[0099] 1-3. Photopolymerization initiator (C) • IRGACURE OXE-02 (manufactured by BASF Japan, oxime ester)

[0100] 1-4. Alumina (D) • Alumina particles (D-1): Manufactured by DENKA Corporation, ASFP-20 (α-saturation: 10%, average particle size 0.3 μm, aspect ratio 1.1) • Alumina particles (D-2): Manufactured by DENKA Corporation, ASFP-40 (α-saturation: 10%, average particle size 0.4 μm, aspect ratio 1.1) • Alumina particles (D-3): ASFP-03S (α-oxidation rate: over 99%, average particle size 0.4 μm, aspect ratio 1.1) • Alumina particles (D-4): Manufactured by DENKA Corporation, DAW-01 (α-saturation: 5%, average particle size 1.9 μm, aspect ratio 1.1) • Alumina particles (D-5): Manufactured by DENKA Corporation, DAW-03 (α-saturation: 30%, average particle size 4.9 μm, aspect ratio 1.1) • Alumina particles (D-6): Manufactured by DENKA Corporation, DAW-10 (α-alloying rate: 50%~80%, average particle size 12.0 μm, aspect ratio 1.1) • Alumina particles (D-7): Manufactured by DENKA Corporation, DAW-20 (α-alloying rate: 50%~80%, average particle size 24.0 μm, aspect ratio 1.1)

[0101] The α-oxidation rate and average particle size of alumina particles were determined using the following methods.

[0102] (Determination of α-conversion rate) X-ray diffraction measurements were performed on powders prepared by mixing α-phase alumina powder AA-05 (manufactured by Sumitomo Chemical Co., Ltd.) and θ-phase alumina powder Taimicron™-100D (manufactured by Daming Chemical Co., Ltd.) in mass ratios of 0:10, 5:5, and 10:0. The integrated intensity of the peak value of the α-phase detected at 2θ=43° was calculated, and a calibration curve of mixing ratio versus integrated intensity was prepared. Secondly, X-ray diffraction measurements were performed on the alumina (D) powder, and the integrated intensity of the peak value at 2θ = 43° was calculated. This value was then compared with the calibration curve to determine the α-phase content, i.e., the α-phase concentration (%). Furthermore, a JDX-3500 X-ray diffraction apparatus (manufactured by Nippon Eiichiro Co., Ltd.) was used for the X-ray diffraction.

[0103] (Determination of average particle diameter) The average particle size of alumina (D) was determined using a Microtrac MT3300.

[0104] (Measurement of aspect ratio) The aspect ratio of alumina (D) is determined by selecting any 20 particles from an image obtained using a scanning electron microscope (SEM), measuring their major and minor axes, and calculating the average major and minor axes. Then, the average major and minor axes are substituted into the following formula to calculate the aspect ratio. Aspect ratio = average major axis (μm) / average minor axis (μm)

[0105] 1-5. Others 1-5-1. Inorganic fillers (E) • Silicon dioxide particles: Manufactured by Admatechs Co., Ltd., SO-C1

[0106] 1-5-2. Organic microparticles • Microparticle polymer F351 (manufactured by Aica Industries)

[0107] 1-5-3. Silane Coupling Agent •Silane coupling agent (KBM-403, manufactured by Shin-Etsu Silicone Co., Ltd.)

[0108] 2. Preparation of liquid crystal sealant (Example 1) Using a three-roll mill, 100 parts by mass of a thermosetting compound (A1), 140 parts by mass of a compound with intramolecular ethylene unsaturated double bonds (A2), 400 parts by mass of a partially epoxy (meth)acrylate (A3), 100 parts by mass of a thermosetting agent (B), 10 parts by mass of a photopolymerization initiator (C), 50 parts by mass of alumina particles (D-1), 130 parts by mass of an inorganic filler (E), 60 parts by mass of organic microparticles (F), and 10 parts by mass of a silane coupling agent (G) are thoroughly mixed in a homogeneous liquid to obtain a liquid crystal sealant.

[0109] (Examples 2-10, Comparative Examples 1-2) Except for the changes in composition as shown in Table 1, the liquid crystal sealant was obtained in the same manner as in Example 1.

[0110] 3. Evaluation The following methods were used to evaluate the adhesion strength, moisture permeability, and liquid crystal contamination of the liquid crystal sealants obtained in Examples 1 to 10 and Comparative Examples 1 to 2.

[0111] <Continue with intensity> Using a dispenser (Shotmaster, manufactured by Musashi Engineering), the obtained liquid crystal sealant was applied to a 38 mm × 38 mm quadrilateral sealing pattern (2500 μm²) on a 40 mm × 45 mm glass substrate (RT-DM88-PIN, manufactured by EHC) that had a transparent electrode and alignment film pre-formed on it. Subsequently, the pairs of glass substrates were bonded under reduced pressure, perpendicular to the glass substrate with the sealing pattern, and then bonded with the atmosphere open. The two bonded glass substrates were then kept in a light-shielding chamber for 1 minute, and then irradiated with 3000 mJ / cm² of visible light (wavelength 370 nm to 450 nm), and then heated at 120°C for 1 hour to harden the seal, thereby obtaining the test piece. For the portion of the obtained test piece 4.5 mm from the corner of the sealing pattern, a vertical indentation tester (Model 210, Intesco) was used to indent vertically at a speed of 5 mm / min. This operation was performed on 10 glass substrates (n=10), and the number of substrates that cracked was counted. The adhesion strength was then evaluated according to the following criteria. ◎: The number of glass substrates that crack is 7 to 10. ○: The number of glass substrates that cracked ranged from 1 to 6. ×: The number of glass substrates that cracked was 0. The more glass substrates that crack, the higher the bonding strength. If it is 0 or above, it is considered to be at a level where there are no practical problems and is judged as good.

[0112] <Moisture permeability> The obtained liquid crystal sealant was applied to the release paper with a thickness of 300 μm using a coating applicator. Then, the applied sealant was placed in a nitrogen purging container and subjected to nitrogen purging for 5 minutes. After that, it was irradiated with light of 3000 mJ / cm2 (light corrected using a 365 nm wavelength sensor) and then heated at 120°C for 1 hour to produce a hardened film.

[0113] Two hardened films were placed on an aluminum cup containing anhydrous calcium chloride as a desiccant, followed by an aluminum ring, which was then tightened with screws. The initial weight of the entire aluminum cup was then measured. The aluminum cup was then placed in a thermostatic bath set to 60°C and 90% RH for 24 hours. Afterward, the aluminum cup was removed and its weight was measured. The obtained weight value was substituted into the following formula to calculate the moisture permeability. Calculation formula: Moisture permeability = (Weight after test - Weight before test) × Membrane thickness / (Membrane area × 100) Then, the evaluation is based on the following benchmarks. ◎: Moisture permeability less than 25 g / m² ○: Moisture permeability is 25 g / m² or higher but less than 30 g / m². ×: Moisture permeability is above 30 g / m² If the score is ○ or above, it indicates a level that is practically problem-free and is judged as good.

[0114] <Liquid crystal pollution> Using a dispenser (Shotmaster, manufactured by Musashi Engineering), the obtained liquid crystal sealant is formed into a 35 mm × 35 mm quadrilateral sealing pattern (3500 μm²) as the main seal on a 40 mm × 45 mm glass substrate (RT-DM88-PIN, manufactured by EHC) with a transparent electrode and alignment film pre-formed thereon. A 38 mm × 38 mm quadrilateral sealing pattern is also formed on its outer periphery. Next, using a dispenser, liquid crystal material (MLC-6609-000, manufactured by Merck) of equivalent volume to that of the laminated panel was precisely dropped into the frame of the main seal. Then, the paired glass substrates were laminated under reduced pressure, followed by atmospheric bonding. The two laminated glass substrates were then held in a light-shielding chamber for 1 minute, and with the main seal shielded by a 36 mm × 36 mm quadrilateral substrate coated with a black matrix, they were irradiated with 500 mJ / cm² of visible light (wavelength 370 nm ~ 450 nm), and then heated at 120°C for 1 hour to harden the main seal. Afterwards, polarizing films were attached to both sides of the obtained liquid crystal cells to obtain a liquid crystal display panel. The liquid crystal contamination was then evaluated according to the following criteria. ◎: Up to the main sealing edge of the LCD panel, the liquid crystals are aligned perfectly with no color unevenness. ○: Uneven color distribution occurs in an area less than 0.5 mm near the edge of the main seal. Δ: Uneven color distribution occurs in an area of ​​0.5 mm or more but less than 1 mm near the edge of the main seal. ×: Uneven coloring occurs in an area of ​​more than 1 mm near the self-sealing edge. If it is Δ or above, it is a level that is practically problem-free and is judged as good.

[0115] The evaluation results of the liquid crystal sealants of Examples 1 to 10 and Comparative Examples 1 to 2 are shown in Table 1.

[0116] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Comparative Example 1 Comparative Example 2 composition Hardening compound (A) Thermosetting compounds (A1) 100 100 100 100 100 50 100 100 100 100 100 100 Compound A2 contains ethylene-like unsaturated double bonds. 140 140 140 140 140 190 140 140 140 140 140 140 Partial epoxy (meth)acrylate (A3) 400 400 400 400 400 400 400 400 400 400 400 400 total 640 640 640 640 640 640 640 640 640 640 640 640 Thermosetting agent (B) 100 100 100 100 100 100 100 100 100 100 100 100 Photopolymerization initiator (C) 10 10 10 10 10 10 10 10 10 10 10 10 Alumina (D) D-1 Alpha conversion rate 10% Average particle diameter: 0.3 μm 50 100 25 50 150 D-2 Alpha conversion rate 10% Average particle diameter: 0.4 μm 50 D-3 Alpha conversion rate exceeds 99% Average particle diameter: 0.4 μm 50 D-4 α-conversion rate 5% Average particle diameter: 1.9 μm 50 D-5 Alpha conversion rate 30% Average particle diameter: 4.9 μm 50 D-6 Alpha conversion rate 50%~80% Average particle diameter: 4.9 μm 50 D-7 Alpha conversion rate 50%~80% Average particle diameter: 4.9 μm 50 total 50 100 25 50 50 50 150 50 50 50 0 50 Inorganic fillers (E) 130 80 155 130 130 130 30 130 130 130 180 130 Organic microparticles (F) 60 60 60 60 60 60 60 60 60 60 60 60 Coupling agent (G) 10 10 10 10 10 10 10 10 10 10 10 10 evaluate Next intensity ◎ ◎ ○ ◎ ○ ○ ◎ ○ ○ ○ × × Moisture permeability ◎ ◎ ○ ◎ ◎ ◎ ◎ ○ ○ ○ × ○ Liquid crystal contamination (uneven color) ◎ ○ ◎ ○ ○ ◎ Δ Δ Δ Δ ◎ ○

[0117] As shown in Table 1, the liquid crystal sealants of Examples 1 to 10, which contain alumina with an α-oxidation rate of less than 80%, all exhibited high adhesion strength to the substrate while maintaining low moisture permeability.

[0118] In particular, it is known that by reducing the average particle size of alumina to below 3.0 μm, color unevenness can be further reduced (comparison of Examples 1, 4, 5, and 8). Furthermore, it is known that by setting the alumina content below a specified level, color unevenness can be further suppressed (comparison of Examples 1-3 and 7).

[0119] In contrast, it can be seen that the liquid crystal sealant of Comparative Example 2, which contains alumina (D-3) with an α-oxidation rate of over 80%, has low adhesion strength to the substrate. Furthermore, it can be seen that the liquid crystal sealant of Comparative Example 1, which does not contain alumina, has high moisture permeability and low adhesion strength to the substrate.

[0120] This application claims priority based on Japanese Patent Application No. 2022-048549, filed on March 24, 2022. The entire contents of that application are incorporated herein by reference. [Industry availability]

[0121] The liquid crystal sealant of the present invention can form a sealing member that has high moisture resistance and high adhesion strength to the substrate. Therefore, the liquid crystal sealant is particularly useful as a liquid crystal sealant for liquid crystal dispensing processes.

[0122] none

Claims

1. A liquid crystal sealant comprising a curable compound (A), a thermosetting agent (B), and aluminum oxide (D) with an α-scaling rate of 80% or less, wherein the curable compound (A) comprises 5 to 20 parts by mass of a thermosetting compound (A1) having an intramolecular epoxy group relative to 100 parts by mass of the curable compound (A) (wherein, The thermosetting compound (A1) does not contain any epoxy (meth)acrylate (A3).

2. The liquid crystal sealant as claimed in claim 1, wherein, The average particle size of the alumina (D) is 0.01 μm to 3 μm.

3. The liquid crystal sealant as claimed in claim 1, wherein, The content of alumina (D) is 1 to 20 parts by mass relative to 100 parts by mass of the curing compound (A).

4. The liquid crystal sealant as claimed in claim 1, wherein, The aspect ratio of the alumina (D) is 2.0 or less.

5. The liquid crystal sealant as claimed in claim 1, wherein, The alumina (D) is in particle form.

6. The liquid crystal sealant as claimed in claim 1, wherein, The content of the thermosetting compound (Al) is 10 to 20 parts by mass relative to 100 parts by mass of the curing compound (A).

7. The liquid crystal sealant as claimed in claim 1, wherein, The content of the thermosetting agent (B) is 10 parts by mass or more relative to 100 parts by mass of the curing compound (A).

8. The liquid crystal sealant as claimed in claim 1, wherein, The thermosetting agent (B) comprises at least one selected from the group consisting of diazinon-based thermosetting agents, imidazole-based thermosetting agents, amine adduct-based thermosetting agents, and polyamine-based thermosetting agents.

9. The liquid crystal sealant as claimed in claim 1, further comprising: a compound (A2) having an intramolecular ethylene unsaturated double bond as said curing compound (A) (wherein, The compound (A2) does not contain any epoxy (meth)acrylate (A3) or photopolymerization initiator (C), and the ratio (A1 / A2) of the thermosetting compound (A1) to the compound (A2) is 30 / 70 to 50 / 50 (mass ratio).

10. The liquid crystal sealant as claimed in claim 1 or 9 further comprises a portion of epoxy (meth)acrylate (A3) as said curing compound (A).

11. The liquid crystal sealant as claimed in claim 9, wherein, The photopolymerization initiator (C) comprises at least one selected from the group consisting of oxime ester compounds, thioxanthone compounds, and anthraquinone compounds.

12. The liquid crystal sealant as claimed in claim 1 further comprises a coupling agent.

13. The liquid crystal sealant as described in claim 1 is a liquid crystal sealant for liquid crystal droplet application.

14. A method for manufacturing a liquid crystal display panel, comprising: The step of forming a sealing pattern of the liquid crystal sealant as described in claim 1 on one of the substrates; The steps include: applying liquid crystal to the area of ​​the sealing pattern or to another substrate paired with one of the substrates while the sealing pattern is not hardened; overlapping one of the substrates with the other substrate separated by the sealing pattern; and hardening the sealing pattern.

15. A method for manufacturing a liquid crystal display panel as described in claim 14, wherein, The step of hardening the sealing pattern includes irradiating the sealing pattern with light to harden the sealing pattern.

16. A method for manufacturing a liquid crystal display panel as described in claim 15, wherein, The light illuminating the sealing pattern includes light from the visible light region.

17. A method for manufacturing a liquid crystal display panel as described in claim 16, wherein, The step of hardening the sealing pattern further includes the step of heating the light-irradiated sealing pattern to harden it.

18. A liquid crystal display panel, comprising: A pair of substrates; A frame-shaped sealing member is disposed between the pair of substrates; And a liquid crystal layer, filling the space between the pair of substrates surrounded by the sealing member, and the sealing member comprising a hardened liquid crystal sealant as described in claim 1.