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

Abstract

The present application relates to a liquid crystal sealing agent, a method for manufacturing a liquid crystal display panel, and a liquid crystal display panel. The liquid crystal sealing agent has a Young's modulus of 0.5 GPa or more and less than 3.0 GPa as measured at 23°C, and contains: a thermally curable compound (A) having an epoxy group in a molecule, a curable compound (B) represented by formula (1) having a characteristic ratio of 4.7 or less, a Tg of 250°C or higher and 340°C or lower, and a weight average molecular weight Mw of 1000 or more, and a thermal curing agent (E), wherein in formula (1), <R0 2 > is a root mean square of all end-to-end distances available to a polymer chain, L is a root mean square of lengths of each constituting unit constituting the polymer chain, n is the number of the constituting units, and the thermal curing agent (E) is a thermal curing agent having a solubility in water of 5 g / 100 g or less at 20°C.

Description

[0001] This application is a divisional application of Chinese patent application filed on March 17, 2022, with application number 202280002862.0 and entitled "Liquid Crystal Sealant, Method for Manufacturing Liquid Crystal Display Panel and Liquid Crystal Display Panel". Technical Field

[0002] This invention relates to liquid crystal sealants, methods for manufacturing liquid crystal display panels, and liquid crystal display panels. Background Technology

[0003] Liquid crystal displays (LCDs) and organic EL displays are widely used in the image display panels of various electronic devices, including mobile phones and personal computers. For example, an LCD panel consists of two transparent substrates with electrodes on their surfaces, a frame-like sealant sandwiched between them, and liquid crystal material encapsulated within the area surrounded by the sealant.

[0004] In order to manufacture liquid crystal display panels that are highly resistant to impacts such as drops, it is necessary to develop highly flexible sealants that can absorb the stress caused by such impacts.

[0005] For example, Patent Document 1 describes a sealant for liquid crystal droplet processing, comprising: a curable resin, a polymerization initiator, and a thermosetting agent (diacylhydrazine-based), wherein the storage modulus of the cured material at 25°C is less than 0.8 GPa, and the storage modulus of the cured material at 121°C is 0.01 GPa or more. According to Patent Document 1, by setting the storage modulus of the cured material at 25°C to less than 0.8 GPa, impact resistance can be improved, and by setting the storage modulus of the cured material at 121°C to 0.01 GPa or more, resistance to damp heat can be improved. Specifically, in Patent Document 1, the aforementioned storage modulus of the cured material is achieved by including a compound having an epoxy group and a rubber structure in the curable resin.

[0006] Furthermore, Patent Document 2 discloses a sealant for liquid crystal droplet processing, which contains a curable resin and a polymerization initiator or thermosetting agent (diazid-based), wherein the storage modulus of the cured material at 25°C is less than 2.0 GPa, and the loss modulus of the cured material at 25°C is 0.1 GPa or more and 1.0 GPa or less. According to Patent Document 2, by reducing the storage modulus of the cured material and setting the loss modulus to a certain level or higher, the cured material can be easily deformed and easily recover its shape (not easily subjected to plastic deformation), thus improving the impact resistance of the cured material, and even if the substrate is repeatedly deformed, it is not easy to peel off or deform. Specifically, in Patent Document 2, by using a compound having polymerizable functional groups and a rubber structure as the curable resin, or by incorporating rubber particles into the sealant, the aforementioned balance between the storage modulus and loss modulus can be achieved.

[0007] Furthermore, Patent Document 3 discloses a liquid crystal sealant for liquid crystal droplet application, which contains a compound having an epoxy group and an acryloyl group within its molecule, and has a glass transition temperature of 90°C or less and a tanδ of 0.5 or more as determined by the DMA method. Additionally, Patent Document 3 discloses the use of a dihydrazide-based thermosetting agent. Moreover, in Patent Document 3, the curing flexibility of the aforementioned sealant is improved, achieving sufficient adhesive strength even in flexible displays and curved displays.

[0008] Furthermore, Patent Document 4 discloses a sealant for liquid crystal droplet processing, comprising: a curable resin, a polymerization initiator or a thermosetting agent, and an inorganic filler having a hydrophobic group on its surface in an amount of 15% by mass or more, wherein the storage modulus of the cured material at 25°C is 2.0 GPa or less. According to Patent Document 4, by setting the storage modulus of the cured material at 25°C to 2.0 GPa or less, panel peeling can be prevented when the liquid crystal display assembly is subjected to impact such as dropping. Patent Document 4 discloses that the aforementioned curable resin is preferably a compound with a soft backbone such as an open-ring structure of cyclic lactones.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: International Publication No. 2020 / 085081

[0012] Patent Document 2: International Publication No. 2018 / 124023

[0013] Patent Document 3: Japanese Patent Application Publication No. 2018-022054

[0014] Patent Document 4: International Publication No. 2018 / 207730 Summary of the Invention

[0015] The problem that the invention aims to solve

[0016] [Issues covered in the first disclosure]

[0017] As described in Patent Documents 1 to 5, various studies have been conducted on sealants that improve their flexibility after curing (reducing Young's modulus) in order to improve resistance to impacts caused by drops, etc. In recent years, there has been a desire to further thin liquid crystal display panels. To achieve this thinning, the glass substrate is sometimes thinned by grinding after the sealant has cured. By improving flexibility, stress and friction on components within the liquid crystal display panel can be reduced; therefore, there is a expectation that liquid crystal display panels can be further thinned.

[0018] However, the inventors have discovered the following problem: if the above-mentioned grinding or other pressure treatment is applied to a liquid crystal display panel with a cured sealant, bright spots (rough spots) will occur in the liquid crystal due to the heat curing agent seeping out from the sealant, resulting in a decrease in display characteristics.

[0019] The first solution of this specification was made in view of the above-mentioned problems, and its object is to provide a liquid crystal sealant with low Young's modulus of cured material that can suppress the generation of rough spots when a liquid crystal display panel having cured liquid crystal sealant is subjected to pressure treatment, a method for manufacturing a liquid crystal display panel using the liquid crystal sealant, and a liquid crystal display panel manufactured using the liquid crystal sealant.

[0020] means for solving problems

[0021] One aspect of the present invention, which addresses the problems disclosed in the first part of this specification, relates to a liquid crystal sealant whose cured product has a Young's modulus of 0.5 GPa or more and less than 3.0 GPa when measured at 23°C. The liquid crystal sealant contains: a thermosetting compound (A) having an intramolecular epoxy group and a thermosetting agent (E), wherein the thermosetting agent (E) is a thermosetting agent with a water solubility of 5 g / 100 g or less at 20°C.

[0022] One aspect of the present invention, addressing the problems disclosed in the second part of this specification, relates to a liquid crystal sealant whose cured product exhibits an elongation of 30% or more at 23°C, and a moisture permeability of less than 50 g / m³ for a cured product with a thickness of 0.6 mm at 60°C and 90% RH. 2 .

[0023] Another aspect of the present invention for solving the above-mentioned problems relates to a method for manufacturing a liquid crystal display panel, comprising: a step of coating a liquid crystal sealant onto the alignment film of one of a pair of substrates, each having an alignment film, to form a sealing pattern; a step of dropping liquid crystal onto the area of ​​the sealing pattern on one of the substrates or onto the other substrate while the sealing pattern is uncured; a step of overlapping the one substrate and the other substrate with the sealing pattern in between; and a step of curing the sealing pattern.

[0024] Another aspect of the present invention for solving the above-mentioned problems relates to a liquid crystal display panel comprising: a pair of substrates each having an alignment film; a frame-shaped sealing member disposed between the alignment films of the pair of substrates; and a liquid crystal layer filling the space between the pair of substrates surrounded by the sealing member, wherein the sealing member is a cured form of the liquid crystal sealant.

[0025] The effects of the invention

[0026] According to the present invention, a liquid crystal sealant having a low Young's modulus after curing and capable of suppressing the generation of rough spots when a liquid crystal display panel having a cured liquid crystal sealant is subjected to pressure treatment, a method for manufacturing a liquid crystal display panel using the liquid crystal sealant, and a liquid crystal display panel manufactured using the liquid crystal sealant are provided. Detailed Implementation

[0027] In addition, in this specification, "(meth)acrylate" refers to acrylate or methacrylate, "(meth)acryloyl" refers to acryloyl or methacryloyl, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid, and "(meth)acrylic resin" refers to acrylic resin or methacrylic resin.

[0028] 1. Liquid crystal sealant

[0029] One embodiment of the present invention relates to a sealant (hereinafter also simply referred to as "sealant") for sealing liquid crystal in a liquid crystal display panel.

[0030] 1-1. Materials

[0031] First, the commonly used materials in the liquid crystal sealants disclosed in each of these disclosures will be described. The liquid crystal sealants described in each disclosure can be used by appropriately selecting and combining the following materials in a manner that satisfies the conditions of each disclosure. Furthermore, these materials are not essential to the liquid crystal sealants described in each disclosure; rather, combinations of various materials are permissible as long as the conditions of each disclosure are met.

[0032] 1-1-1. Curing Resin

[0033] 1-1-1-1. Thermosetting compounds with intramolecular epoxy groups (A)

[0034] In the liquid crystal sealants disclosed above, the curable resin may contain a thermosetting compound (A) having two or more epoxy groups within its molecule. However, in this specification, the thermosetting compound (A) does not contain any of the epoxy (meth)acrylates described later.

[0035] The thermosetting compound (A) can be any of a monomer, oligomer, or polymer. The thermosetting compound (A) can further reduce the moisture permeability of the cured product and improve the display characteristics of the resulting liquid crystal panel, thereby enhancing the reliability of the liquid crystal display panel.

[0036] The weight-average molecular weight of the thermosetting compound (A) is preferably 500 or more and 10,000 or less, more preferably 500 or more and 5,000 or less. The weight-average molecular weight of the thermosetting compound (A) is determined using gel permeation chromatography (GPC) and converted to polystyrene.

[0037] The thermosetting compound (A) 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, such as bisphenol A, bisphenol S, bisphenol E, bisphenol F, and bisphenol AD, 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, such as phenol or cresol-formaldehyde-derived phenolic varnish resins, or polyphenols, such as polyolefin phenol or their copolymers, with epichlorohydrin; and glycidyl ether compounds of xylene-methylphenol resins, etc. Preferably, the epoxy compound is a cresol-phenolic varnish-type epoxy compound, a 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 thermosetting resin composition (A) may contain only one type of epoxy compound or may contain two or more types.

[0038] Furthermore, in Patent Documents 1 and 3, the flexibility of the cured product is improved by using epoxy compounds containing structures with unsaturated bonds or siloxane structures (rubber structures) within the molecule. However, according to the present invention, compounds with the aforementioned rubber structures readily dissolve in liquid crystals, becoming a cause of liquid crystal contamination. Therefore, the thermosetting compound (A) preferably does not substantially contain unsaturated bonds or siloxane structures within its molecule. Specifically, the content of unsaturated bonds or siloxane structures in the molecule is preferably 5% by mass or less, more preferably 1% by mass or less.

[0039] The thermosetting compound (A) can be in a liquid or solid state. From the viewpoint of further reducing the moisture permeability of the cured product, a solid epoxy compound is preferred. The softening point of the solid epoxy compound is preferably 40°C or higher and 150°C or lower. The softening point can be determined according to the ring and ball method specified in JIS K 7234 (1986).

[0040] 1-1-1-2. Specific Curable Compounds (B)

[0041] In the liquid crystal sealants disclosed above, the curing resin may also contain a curing resin (B) with a characteristic ratio of 4.70 or less, a Tg of 250°C or more and 340°C or less, and a weight-average molecular weight (Mw) of 1,000 or more.

[0042] The aforementioned "characteristic ratio" is a value representing the flexibility of molecules; it is a parameter that indicates the greater the curling as the value decreases.

[0043] [Number 1]

[0044]

[0045] In equation (1), <R0 2 > is the root mean square of all possible distances between the ends of the polymer chain. L is the root mean square of the lengths of the constituent units that make up the polymer chain, and n is the number of constituent units.

[0046] The curable compound (B) with a characteristic ratio of 4.70 or less can exhibit a stable structure in a more coiled state than other resins. Therefore, the specific curable compound (B) is generally in a coiled state, but can be stretched when stress is applied to the cured sealant. Furthermore, because the specific curable compound (B) has a large state change between this coiled and stretched state, it is also easy to expand and contract after curing, which can be considered to improve the softness and stretchability of the cured liquid crystal sealant. In addition, by utilizing the specific curable compound (B) to ensure softness and stretchability, even if other materials or compounds with intramolecular structures that are difficult for water to penetrate are used as the specific curable compound (B), the softness and stretchability of the cured product are not easily compromised. From the above viewpoint, the characteristic ratio of the specific curable compound (B) is preferably 4.70 or less, more preferably 4.50 or less. There is no particular upper limit to the characteristic ratio of the specific curable compound (B), but from the viewpoint of making the viscosity more stable, it is preferably 4.30 or more.

[0047] The above characteristic ratio can be set as a value calculated using the Bicerano method. The Bicerano method is a method for calculating predicted resin properties, described in "Prediction of Polymer Properties" by Joseph Bicerano, Marcel Dekker, New York, 2002.

[0048] The aforementioned specific curable compound (B) may be, for example, a resin having intramolecular hydrogen bonds, a resin having an ortho-substituted aromatic ring, or a resin having a ketone group in the repeating structural portion.

[0049] The aforementioned specific curable compound (B) can be any curable compound, such as a photocurable compound or a thermocurable compound, but from the viewpoint of suppressing liquid crystal contamination caused by dissolution into the liquid crystal during the curing process of the sealant by heating, a photocurable compound is preferred. The specific curable compound (B) described above as a photocurable compound is more preferably a compound having an intramolecular vinyl unsaturated double bond (excluding some epoxy (meth)acrylates), and from the viewpoint of high reactivity, a compound having a (meth)acryloyl group is even more preferred.

[0050] The specific curable compound (B) mentioned above is preferably a curable compound represented by the following general formula (1).

[0051] [Chemistry 1]

[0052]

[0053] General formula (1)

[0054] In general formula (1), R1 represents a divalent residue derived from a polycyclic epoxy compound; R2 independently represents a divalent structure obtained by opening a cyclic lactone; R3 independently represents a straight-chain or branched alkylene group with 1 or more carbon atoms and 6 or fewer carbon atoms; and R4 independently represents a hydrogen atom or a methyl group.

[0055] R1 is a divalent residue derived from a polycyclic epoxy compound. Examples of polycyclic epoxy compounds include:

[0056] Bisphenol type epoxy resins, such as bisphenol A type epoxy resin, bisphenol E type epoxy resin, and bisphenol F type epoxy resin;

[0057] Hydrogenated bisphenol type epoxy resin;

[0058] Phenolic varnish-type epoxy resin;

[0059] Biphenyl-type epoxy resin;

[0060] Epoxy resin of the zirconia type;

[0061] Hydroquinone type epoxy resin;

[0062] Naphthalene skeleton type epoxy resin;

[0063] Tetrahydroxyphenyl ethane type epoxy resin;

[0064] Trihydroxyphenylmethane type epoxy resin;

[0065] Dicyclopentadiene phenolic epoxy resin;

[0066] Alicyclic epoxy resins such as 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate and 1,2-epoxy-4-(2-epoxyethoxyalkyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol;

[0067] Polyglycidyl esters of polybasic acids such as diglycidyl ester of hexahydrophthalic anhydride;

[0068] Sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polypropylene glycol diglycidyl ether, dipropylene glycol polyglycidyl ether, glycerol polyglycidyl ether, hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and cyclohexanediethanol diglycidyl ether are among the glycidyl ethers mentioned above.

[0069] Diene polymeric epoxy resins such as polybutadiene or polyisoprene;

[0070] Glycidylamine type epoxy resins include tetraglycidyl diaminodiphenylmethane, tetraglycidyl diaminomethylcyclohexane, diglycidyl aniline, and tetraglycidyl m-phenylenediamine.

[0071] Epoxy resins containing heterocyclic compounds, such as triazine or hydantoin.

[0072] From the viewpoint of further improving the adhesion and heat resistance of the sealant, R1 is preferably a divalent structure as shown in the following general formula (2).

[0073] [Chemistry 2]

[0074]

[0075] In general formula (2), X represents a single bond, methylene, methylmethylene, dimethylmethylene, methylphenylmethylene, cyclohexylene, sulfonyl, ether bond, or thioether bond.

[0076] Furthermore, from the viewpoint of further improving the flexibility of the cured material (reducing Young's modulus), X in general formula (2) is preferably methylene.

[0077] R2 is a divalent structure obtained by opening the ring of a cyclic lactone. The type of cyclic lactone is not particularly limited, but it is preferably a cyclic lactone with 2 or more carbon atoms and 6 or fewer carbon atoms, more preferably a cyclic lactone with 4 or more carbon atoms and 6 or fewer carbon atoms. Examples of such cyclic lactones include α-acetyl lactone (2 carbon atoms), β-propiolactone (3 carbon atoms), γ-butyrolactone (4 carbon atoms), δ-valerolactone (5 carbon atoms), and ε-caprolactone (6 carbon atoms). Furthermore, R2 can be substituted. From the viewpoint of further improving the elasticity of the curable compound and further improving the flexibility of the sealant (further reducing Young's modulus), R2 is preferably derived from structures of β-propiolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone, more preferably from structures of γ-butyrolactone, δ-valerolactone, and ε-caprolactone.

[0078] Specifically, R2 is a bivalent structure as shown in the following general formula (3).

[0079] [Chemistry 3]

[0080]

[0081] In general formula (3), Y is an alkylene group having 2 or more carbon atoms and 6 or fewer carbon atoms, preferably 3 or more carbon atoms and 6 or fewer carbon atoms, and more preferably 4 or more carbon atoms and 6 or fewer carbon atoms.

[0082] In addition, Y can be substituted. Examples of substituents include methyl, ethyl, propyl, butyl, pentyl, hexyl, etc.

[0083] Alternatively, R2 can also be repeated from the divalent structure (the divalent structure shown in general formula (3)) obtained by opening the ring of the above-mentioned cyclic lactone. In this case, there is no particular limitation on the number of repetitions, but it is preferably 1 or more and 6 or less, more preferably 1 or more and 5 or less.

[0084] R3 is preferably a straight-chain or branched alkylene group having 1 or more but 6 or fewer carbon atoms. Examples of such alkylene groups include ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, and hexyl. Among these, from the viewpoint of further reducing the moisture permeability of the sealant, R3 is preferably methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, or tert-butyl, and more preferably ethyl, propyl, or isopropyl.

[0085] In addition, Y can be substituted. Examples of substituents include methyl, ethyl, propyl, butyl, pentyl, hexyl, etc.

[0086] R4 is a hydrogen atom or a methyl group.

[0087] The curable compound represented by general formula (2) is a difunctional (meth)acrylic resin having a repeating structure containing a ketone group and an ortho-substituted benzene ring. According to the inventors' understanding, the curable compound represented by general formula (2) with this structure is more likely to improve the performance ratio. Furthermore, because the curable compound represented by general formula (2) has a large molecular weight, it is less likely to dissolve in the liquid crystal, thus easily suppressing liquid crystal contamination caused by the sealant dissolving in the liquid crystal.

[0088] The curable compound represented by general formula (2) can be synthesized by known methods. For example, by loading a (meth)acrylate with hydroxyl groups, phthalic anhydride and a cyclic lactone into a reaction flask, introducing dry air in the presence of a polymerization inhibitor, and reacting them while refluxing and stirring, then adding a polycyclic epoxy compound, introducing dry air, and reacting them while refluxing and stirring, the curable compound represented by general formula (2) can be synthesized.

[0089] The specific curable compound (B) has a weight-average molecular weight (Mw) of 1000 or more. The weight-average molecular weight (Mw) is preferably 1000 or more and 2000 or less, more preferably 1200 or more and 1800 or less, and even more preferably 1400 or more and 1600 or less. If the Mw of the specific curable compound (B) is 1000 or more, the flexibility of the cured product can be further improved (Young's modulus can be further reduced), and the tensile strength of the cured product can also be further improved. If the Mw of the specific curable compound (B) is 2000 or less, the moisture permeability of the sealant can be further reduced. The Mw of the specific curable compound (B) is a value determined using gel permeation chromatography (GPC) with polystyrene as a standard.

[0090] Furthermore, the glass transition temperature (Tg) of the specific curable compound (B) is 250°C or higher and 340°C or lower, preferably 260°C or higher and 320°C or lower, and more preferably 280°C or higher and 310°C or lower. If the glass transition temperature is 250°C or higher, the moisture permeability can be reduced. If the glass transition temperature is 340°C or lower, the cured liquid crystal sealant can be made more flexible.

[0091] 1-1-1-3. Other curable compounds (C)

[0092] The sealant described above may also contain other curing compounds (C) besides those mentioned above as curing resins. These other curing compounds (C) can be any curing compound, such as light-curing compounds or thermosetting compounds. Examples of these other curing compounds (C) include compounds having intramolecular vinyl unsaturated double bonds (excluding some epoxy (meth)acrylates).

[0093] The other curable compound (C) may be a monomer, oligomer, or polymer. Examples of the other curable compound (C) include compounds having an intramolecular (meth)acrylyl group. Each molecule of the compound having the (meth)acrylyl group may have one or more (meth)acrylyl groups.

[0094] Examples of curable compounds containing one (meth)acryloyl group per molecule include alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and 2-hydroxyethyl methacrylate.

[0095] Examples of curable compounds having two or more (meth)acryloyl groups per molecule include: di(meth)acrylates derived from polyethylene glycol, propylene glycol, and polypropylene glycol; di(meth)acrylates derived from tri(2-hydroxyethyl) isocyanurate; di(meth)acrylates derived from a diol obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol; di(meth)acrylates derived from a diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A or bisphenol F; di(meth)acrylates or tri(meth)acrylates derived from a polyol obtained by adding 2 or 3 moles of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane; di(meth)acrylates derived from a diol obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A; tri(2-hydroxyethyl) isocyanurate; 2-Hydroxyethyl) ester tri(meth)acrylate, trimethylolpropane tri(meth)acrylate or oligomers thereof; pentaerythritol tri(meth)acrylate or oligomers thereof; dipentaerythritol poly(meth)acrylate; tri(acryloyloxyethyl) isocyanurate; caprolactone-modified tri(acryloyloxyethyl) isocyanurate; caprolactone-modified tri(methacryloyloxyethyl) isocyanurate; alkyl-modified dipentaerythritol poly(meth)acrylate; caprolactone-modified dipentaerythritol poly(meth)acrylate; neopentyl glycol di(meth)acrylate with hydroxypentaerythritol; caprolactone-modified neopentyl glycol di(meth)acrylate with hydroxypentaerythritol; ethylene oxide-modified phosphate (meth)acrylate; ethylene oxide-modified alkylated phosphate (meth)acrylate; and oligo(meth)acrylates of neopentyl glycol, trimethylolpropane and pentaerythritol, etc.

[0096] As described above, compounds with structures containing unsaturated bonds or siloxane structures (rubber structures) within their molecules are easily dissolved in liquid crystals, potentially causing liquid crystal contamination. Furthermore, the aforementioned photocurable compounds with rubber structures tend to reduce the flexibility of the cured product compared to other photocurable compounds. Therefore, this other curable compound (C) preferably does not substantially contain unsaturated bonds or siloxane structures within its molecules. Specifically, the content of unsaturated bonds or siloxane structures in the molecule is preferably 5% by mass or less, more preferably 1% by mass or less.

[0097] 1-1-1-4. Partially epoxy (meth)acrylates (D)

[0098] In the above-mentioned sealant, as a curing resin, a portion of epoxy (meth)acrylate (D) may also be contained. The presence of epoxy (meth)acrylate (D) can improve the adhesion of the cured sealant to the substrate.

[0099] Partially epoxy (meth)acrylates (D) are compounds containing both epoxy and (meth)acryloyl groups within their molecules. They are partially (meth)acryloyl-modified epoxy resins in which at least one epoxy group in a difunctional or higher epoxy resin is modified by a (meth)acryloyl group. Partially epoxy (meth)acrylates (D) can be obtained by known methods, such as reacting a difunctional or higher epoxy resin with (meth)acrylic acid in the presence of a basic catalyst.

[0100] Epoxy resins that serve as raw materials for partial epoxy (meth)acrylates (D) 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'-diallyl bisphenol A, bisphenol AD, and hydrogenated bisphenol; phenolic varnish-type epoxy resins such as phenolic varnish-type, cresol varnish-type, biphenyl varnish-type, and triphenol varnish-type; biphenyl-type epoxy resins; and naphthalene-type epoxy resins, etc.

[0101] Among these, from the viewpoint of low crystallinity and high coating stability, bisphenol type epoxy resins such as bisphenol A and bisphenol F are preferred.

[0102] Furthermore, the epoxy resin described above can be an epoxy resin having 3, 4, or more epoxy groups. However, from the viewpoint of moderately improving the adhesion strength of the cured product to the substrate by appropriately adjusting the crosslinking density, a 2-functional epoxy resin is preferred.

[0103] The epoxy (meth)acrylate (D) preferably has a molar ratio of (meth)acryloyl groups to epoxy groups of 1 or more, more preferably 2 or more. By increasing the molar ratio of (meth)acryloyl groups, liquid crystal contamination caused by the sealant dissolving into the liquid crystal is easily suppressed.

[0104] The weight-average molecular weight (Mw) of the epoxy (meth)acrylate (D) determined by gel permeation chromatography (GPC) is preferably 300 or more and 500 or less.

[0105] 1-2. Thermosetting agent (E)

[0106] The above-mentioned sealant may also contain a thermosetting agent (E) for curing thermosetting components such as thermosetting compound (A), other curing compound (C), and some epoxy (meth)acrylate (D).

[0107] The thermosetting agent (E) is preferably a latent thermosetting agent. A latent thermosetting agent is a compound that does not cure the thermosetting compound (A) or other curing compounds (C) under normal storage conditions (room temperature, visible light, etc.), but will cure these compounds when heat is applied. The thermosetting agent (E) is preferably a curing agent capable of curing epoxy compounds (hereinafter also referred to as "epoxy curing agent").

[0108] From the viewpoint of improving the viscosity stability of the photothermal curing resin composition without compromising the moisture resistance of the cured product, the melting point of the epoxy curing agent is preferably 50°C or higher and 250°C or lower, more preferably 100°C or higher and 200°C or lower, and even more preferably 150°C or higher and 200°C or lower.

[0109] Examples of epoxy curing agents include: dihydrazide-based latent heat curing agents, imidazole-based latent heat curing agents, dicyandiamide-based latent heat curing agents, amine adduct-based latent heat curing agents, and polyamine-based latent heat curing agents. Among these, dihydrazide-based latent heat curing agents, imidazole-based latent heat curing agents, amine adduct-based latent heat curing agents, and polyamine-based latent heat curing agents are preferred. From the viewpoint of further improving display properties, imidazole-based latent heat curing agents, amine adduct-based latent heat curing agents, and polyamine-based latent heat curing agents are more preferred, and amine adduct-based latent heat curing agents and polyamine-based latent heat curing agents are even more preferred.

[0110] Examples of diacid hydrazide-based heat-latent curing agents include: adipate diacid hydrazide (melting point 181℃), 1,3-bis(hydrazylcarbonylethyl)-5-isopropylhydantoin (melting point 120℃), 7,11-octadecadiene-1,18-dicarboxyhydrazide (melting point 160℃), dodecanoic acid diacid hydrazide (melting point 190℃), and sebacic acid diacid hydrazide (melting point 189℃), etc.

[0111] Examples of imidazole-based heat-latent curing agents include 2,4-diamino-6-[2'-ethylimidazolyl-(1')]-ethyltriazine (melting point 215-225°C) and 2-phenylimidazolium (melting point 137-147°C).

[0112] Examples of dicyandiamide-based heat-latent curing agents include dicyandiamide (melting point 209°C), etc.

[0113] Amine adduct-based latent heat curing agents are latent heat curing agents composed of addition compounds obtained by reacting catalytically active amine compounds with any compound. Examples of amine adduct-based latent heat 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), all manufactured by Aminomo Chemical Co., Ltd.

[0114] Polyamine-based heat-latent curing agents are heat-latent curing agents with polymer structures obtained by reacting amines with epoxy resins. Examples include ADK HARDENEREH 4339S (softening point 120-130°C) and ADK HARDENEREH 4357S (softening point 73-83°C) manufactured by ADEKA Corporation.

[0115] 1-3. Photopolymerization initiator (F)

[0116] The sealant may also contain a photopolymerization initiator (F) for initiating the curing (polymerization) of a specific curable compound (B), other curable compounds (C), and some photocurable components such as epoxy (meth)acrylate (D).

[0117] There are no particular restrictions on the photopolymerization initiator (F), as long as it is a compound that can initiate the curing (polymerization) of these compounds. For example, the photopolymerization initiator (F) can be a free radical polymerization initiator, a self-destructive photopolymerization initiator, or a hydrogen-abstracting inorganic photopolymerization initiator.

[0118] Examples of self-degrading photopolymerization initiators include: alkyl phenyl ketone compounds, acylphosphine oxide compounds, diaceticolide compounds, acetophenone compounds, phenyl glyoxylate compounds, benzoin ether compounds, and oxime ester compounds. Examples of the aforementioned alkyl phenyl ketone compounds include: benzoyladium dimethyl ketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one (BASF IRGACURE 651); α-aminoalkyl phenyl ketones such as 2-methyl-2-morpholino(4-methylthiophenyl)propane-1-one (BASF IRGACURE 907); and α-hydroxyalkyl phenyl ketones such as 1-hydroxy-cyclohexyl-phenyl ketone (BASF IRGACURE 184). Examples of the aforementioned acylphosphine oxide compounds include: 2,4,6-trimethylbenzoyl diphenylphosphine oxide. Examples of the aforementioned titanium-based compounds include bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrolo-1-yl)-phenyl)titanium salt, etc. Examples of the aforementioned acetophenone-based compounds include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, benzoyladium dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)one, 1-hydroxycyclohexyl-phenylene, 2-methyl-2-morpholino(4-methylthiophenyl)propane-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, etc. Examples of the aforementioned phenylglyoxylate-based compounds include methyl phenylglyoxylate, etc. Examples of the above-mentioned benzoin ether compounds include benzoin, benzoin methyl ether, and benzoin isopropyl ether. Examples of the above-mentioned oxime ester compounds include 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzoyl oxime)] (BASF IRGACURE OXE 01) and acetone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime) (BASF IRGACURE OXE 02).

[0119] Examples of hydrogen-abstracting photopolymerization initiators include benzophenone compounds, thioxanthone compounds, anthraquinone compounds, and benzoyl compounds. Examples of the aforementioned benzophenone 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-butylcarbonyl peroxide)benzophenone, and 3,3'-dimethyl-4-methoxybenzophenone. Examples of the aforementioned 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), etc. Examples of the aforementioned 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 Co., Ltd.), etc.

[0120] The absorption wavelength of the photopolymerization initiator (F) is not particularly limited; for example, it can be a photopolymerization initiator that absorbs light with a wavelength of 360 nm or higher. More preferably, it absorbs light in the visible light region; even more preferably, it absorbs light with a wavelength of 360 nm or higher and 780 nm or lower; and particularly preferably, it absorbs light with a wavelength of 360 nm or higher and 430 nm or lower.

[0121] Examples of photopolymerization initiators that absorb light with wavelengths above 360 ​​nm include: alkyl phenyl ketone compounds, acylphosphine oxide compounds, titanoceramic compounds, oxime ester compounds, thioxanone compounds, and anthraquinone compounds. Among these, oxime compounds are preferred.

[0122] The molecular weight of the photopolymerization initiator (F) can be, for example, 200 or more and 5000 or less. If the molecular weight of the photopolymerization initiator (F) is 200 or more, it is less likely to dissolve in the liquid crystal. On the other hand, if the molecular weight of the photopolymerization initiator (F) is 5000 or less, its compatibility with various curable resins is improved, and the curing properties of the sealant are easily and well achieved. More preferably, the molecular weight of the photopolymerization initiator (F) is 230 or more and 3000 or less, and even more preferably, it is 230 or more and 1500 or less.

[0123] The molecular weight of the photopolymerization initiator (F) can be determined as the "relative molecular mass" of the molecular structure of the main peak detected when analyzed by high performance liquid chromatography (HPLC).

[0124] Specifically, a sample solution is prepared by dissolving the photopolymerization initiator (F) in THF (tetrahydrofuran), and then analyzed by high-performance liquid chromatography (HPLC). The area percentage of each detected peak (the ratio of the area of ​​each peak to the total area of ​​all peaks) is then calculated to confirm the presence of a dominant peak. The "dominant peak" refers to the peak with the highest intensity (highest peak height) among all peaks detected at the characteristic detection wavelength of each compound (e.g., 400 nm for thioxanthone compounds). The relative molecular mass corresponding to the peak apex of the detected dominant peak can be determined using liquid chromatography / mass spectrometry (LC / MS).

[0125] 1-4. Inorganic fillers (G)

[0126] The sealant described above may also contain inorganic filler (G). In addition to imparting a predetermined hardness and linear expansion to the cured material, inorganic filler (G) also inhibits the penetration of moisture through the interior of the cured material, further reducing the moisture permeability of the cured material.

[0127] Examples of inorganic fillers (G) include: calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, titanium nitride, aluminum oxide, 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.

[0128] The inorganic filler (G) can be in a fixed shape such as spherical, plate-like, or needle-like, or it can be in a non-fixed shape. When the inorganic filler (G) is spherical, its average primary particle size is preferably 1.5 μm or less. Furthermore, the specific surface area of ​​the inorganic filler (G) is preferably 0.5 m². 2 / g or more and 20m 2 / g or less. The average primary particle size of the inorganic filler (F) can be determined by laser diffraction as described in JIS Z 8825 (2013). The specific surface area of ​​the filler can be determined by the BET method as described in JIS Z8830 (2013).

[0129] 1-5. Others

[0130] In addition to the components mentioned above, the sealant may also contain: thermal free radical generators, organic microparticles, coupling agents such as silane coupling agents, ion scavengers, ion exchangers, leveling agents, pigments, dyes, sensitizers, plasticizers, and defoamers.

[0131] Examples of the aforementioned thermal free radical polymerization initiators include: organic peroxides, azo compounds, benzoin derivatives, benzoin ethers, and acetophenones.

[0132] The aforementioned organic microparticles can reduce residual stress during sealant application. For example, the aforementioned organic microparticles can be configured as organic microparticles having an elastic core and an outer shell. The elastic core contains conjugated diene rubber and silicone rubber, etc., and the outer shell is composed of polymers such as (meth)acrylates, vinyl monomers, and epoxy monomers that improve compatibility with other components.

[0133] Examples of the aforementioned silane coupling agents include: vinyltrimethoxysilane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-epoxypropoxypropyltrimethoxysilane, and γ-epoxypropoxypropyltriethoxysilane.

[0134] In addition, the aforementioned sealant may further contain spacers for adjusting the gaps between liquid crystal display panels.

[0135] Descriptions of the liquid crystal sealants disclosed herein

[0136] 2-1. First Publication

[0137] 2-1-1. Instructions for Liquid Crystal Sealant

[0138] The first disclosure of this specification relates to a liquid crystal sealant, the cured form of which has a low Young's modulus and can suppress the generation of rough spots when a liquid crystal display panel having the cured liquid crystal sealant is subjected to pressure treatment.

[0139] The cured sealant has a Young's modulus of 0.5 GPa or more and less than 3.0 GPa as measured at 23°C. The sealant contains: a thermosetting compound (A) with an intramolecular epoxy group, and a thermosetting agent (E) with a water solubility of 5 g / 100 g or less at 20°C. The Young's modulus is preferably 0.5 GPa or more and 2.0 GPa or less, more preferably 0.5 GPa or more and 1.5 GPa or less, and even more preferably 0.5 GPa or more and 1.0 GPa or less. By setting it within the above range, the flexibility of the sealant can be further improved, the drop resistance of the liquid crystal display panel can be improved, and the moisture permeability can be reduced, thereby improving the reliability of the liquid crystal display panel.

[0140] The Young's modulus mentioned above is specifically determined according to the following method.

[0141] Apply the sealant to the release paper to a thickness of 100 μm using an applicator. Then, place the applied sealant into a nitrogen purging container, purge with nitrogen for 5 minutes, and irradiate with 3000 mJ / cm² gas. 2 The light (corrected by a 365nm wavelength sensor) is then heated at 120°C for 1 hour to create a cured film.

[0142] After the obtained cured film was cut into strips (150 mm long and 10 mm wide), a tensile test was performed using an Autograph tensile testing machine (Shimadzu Corporation, AG-X) at room temperature (23°C) at a test speed of 10 mm / min. The Young's modulus was calculated from the slope of stress and strain in the elastic region.

[0143] Sealants possessing the aforementioned Young's modulus can be formulated using various methods. For example, by using epoxy resins containing silicone, epoxy resins containing polyethylene glycol or polypropylene glycol, epoxy resins containing urethane bonds, or epoxy resins with a rubber structure as thermosetting compounds (A), and adjusting their content ratio, the sealant can be endowed with the aforementioned properties. Alternatively, by using resins with relatively long alkyl groups, or by using flexible compounds with aromatic rings within the molecule, the sealant can be endowed with the aforementioned properties.

[0144] Furthermore, as mentioned above, sealants with a low Young's modulus after curing have the characteristic that the cured sealant is less prone to cracking when subjected to pressure treatment after curing. Therefore, sealants with a Young's modulus within the aforementioned range are effectively used for pressure treatments such as thin-film forming of liquid crystal display panels after curing and grinding the substrate. On the other hand, liquid crystal display panels subjected to pressure treatment after curing sometimes develop bright spots (rough spots) in the liquid crystal due to the thermal curing agent seeping out from the sealant. On the other hand, liquid crystal display panels that do not undergo pressure treatment do not develop rough spots.

[0145] The inventors believe that the aforementioned roughness occurs due to the following mechanism: During the manufacture of a liquid crystal display panel, a pattern is formed on a substrate by an uncured sealant and liquid crystal. After another substrate is stacked on top, the sealant is cured. In this step, during the idle time before stacking another substrate after the pattern is formed by the sealant and liquid crystal, moisture from the environment may slightly enter the liquid crystal. If another substrate is stacked in this state and the sealant is cured by heating, the thermosetting agent in the sealant will seep into the liquid crystal. Conventionally, to suppress seepage into the hydrophobic liquid crystal, hydrophilic materials are preferred as thermosetting agents. However, if a hydrophilic thermosetting agent is used, the thermosetting agent, whose mobility is increased during heating, will be attracted by moisture in the liquid crystal and seep into it. It is believed that this seeped thermosetting agent will accumulate in the liquid crystal due to pressure processing or vibration during grinding, causing bright spots (roughness).

[0146] In the above mechanism, it is believed that if the attraction of the thermosetting agent by moisture in the liquid crystal is suppressed, the occurrence of bright spots (rough spots) can be suppressed. Based on this concept, in this disclosure, a hydrophobic thermosetting agent that satisfies the condition that its solubility in water at 20°C is 5 g / 100 g or less is used as the thermosetting agent (E).

[0147] The solubility of the thermosetting agent (E) was determined as follows: 100g of water and a predetermined amount of curing agent were added to a 300mL beaker and mixed and stirred for 2 hours. The product was considered dissolved when it appeared to be completely transparent. Then, the amount of thermosetting agent (E) added to the water was gradually reduced while adding, mixing, and visually judging the product. The concentration of the thermosetting agent (E) that was first judged to be dissolved was set as the solubility value described above.

[0148] Furthermore, for the aforementioned liquid crystal sealant, while measuring the storage modulus (G') and loss modulus (G”) using a dynamic viscoelasticity measuring device (rheometer), and heating the liquid crystal sealant at 25°C in a 120°C (constant temperature) environment, the time until G' and G” become consistent is preferably 450 seconds or less, more preferably 440 seconds or less, and even more preferably 430 seconds or less. The point at which G' and G” become consistent is also called the "gel point," which is the point at which the overall behavior of the composition changes from a liquid state (G” is dominant) to a solid state (G' is dominant). Moreover, if the gel point is exceeded, G' will rise sharply, and the composition will solidify rapidly. For a given composition, the shorter the time to reach the gel point during heating, the easier it is for the composition to solidify at that heating temperature.

[0149] In this disclosure, a shorter time to reach the gel point when heated at a low temperature such as 120°C indicates superior low-temperature curability of the liquid crystal sealant. As mentioned above, while the hydrophobic thermosetting agent used in this disclosure suppresses the formation of bright spots (rough spots), it also tends to exude into the liquid crystal during curing (heating) due to its high affinity for hydrophobic liquid crystal molecules, as is known in the past. In particular, when it is desired to make the liquid crystal sealant capable of low-temperature curing to increase substrate selectivity, the liquid crystal sealant is often cured by prolonged heating at a low temperature. To suppress excessive exude of the thermosetting agent due to this prolonged heating, it is preferable that the liquid crystal sealant can cure in a short time even at low temperatures.

[0150] Liquid crystal sealants that achieve a shorter time to the gel point described above can be formulated using various methods. For example, by selecting the substance described later as the thermosetting agent (E), using a multifunctional epoxy resin, or adding a thermal free radical generator, the time to the gel point can be shortened to the range described above.

[0151] Furthermore, the aforementioned sealant preferably has a cured product with a thickness of 0.6 mm and a moisture permeability of less than 50 g / m³ at 60°C and 90% Rh. 2 .

[0152] The aforementioned moisture permeability is specifically measured using the following method.

[0153] Apply the sealant to the release paper to a thickness of 300 μm using an applicator. Then, place the applied sealant into a nitrogen purging container, purge with nitrogen for 5 minutes, and irradiate with 3000 mJ / cm² gas. 2 The light (corrected by a 365nm wavelength sensor) is then heated at 120°C for 1 hour to create a cured film.

[0154] Two cured films were placed inside an aluminum cup containing anhydrous calcium chloride as a desiccant. An aluminum ring was then placed on top and tightened with screws. The initial weight of the entire aluminum cup was measured. The cup was then placed in a thermostatic bath set to 60°C and 90% RH for 24 hours. Afterward, the cup was removed and its weight measured. The moisture permeability was calculated using the obtained weight value in the following formula.

[0155] Calculation formula:

[0156] Moisture permeability = (Weight after test - Weight before test) × Film thickness / (Film area × 100)

[0157] Sealants with the aforementioned moisture permeability can be formulated using various methods. For example, the aforementioned properties can be imparted to sealants by using flexible compounds with aromatic rings within their molecules, or by using compounds with coiled structures as stabilizing structures.

[0158] The following is a more specific description of a sealant having the above-mentioned properties. The sealant preferably contains: a curable resin, a photopolymerization initiator or thermosetting agent for curing the curable resin, and other substances such as inorganic fillers.

[0159] The viscosity of the sealant, as measured using an E-type viscometer at 25°C and 2.5 rpm, is preferably 200 Pa·s or more and 450 Pa·s or less, more preferably 300 Pa·s or more and 400 Pa·s or less. If the viscosity is within the above range, the sealant exhibits good spreadability when using a dispensing machine.

[0160] 2-1-2. Combinations of materials used in the first disclosure, etc.

[0161] In the liquid crystal sealant disclosed in the first disclosure, a thermosetting agent with a water solubility of 5 g / 100 g or less at 20°C is used as the thermosetting agent (E). Furthermore, a wide range of thermosetting compounds (A), specific curable compounds (B), other curable compounds (C), partially epoxy (meth)acrylates (D), photopolymerization initiators (F), inorganic fillers (G), and other materials can be used. In this case, the type of resin can be appropriately selected such that the Young's modulus of the cured product measured at 23°C is 0.5 GPa or more and less than 3.0 GPa.

[0162] The thermosetting compound (A) can adjust various physical properties of liquid crystal sealants. For example, as described above, by using epoxy resins containing silicone, epoxy resins having polyethylene glycol or polypropylene glycol, epoxy resins having urethane bonds, epoxy resins having a rubber structure, etc., as thermosetting compound (A), the Young's modulus of the cured product can be reduced.

[0163] When the total mass of the curable resin is set to 100 parts by mass, the content of the thermosetting compound (A) is preferably 3 parts by mass or more and 30 parts by mass or less. If the content of the thermosetting compound (A) is 3 parts by mass or more, the moisture permeability of the cured product can be further reduced, and the display characteristics of the obtained liquid crystal panel can be improved. If the content of the thermosetting compound (A) is 30 parts by mass or less, the flexibility of the cured product can be improved more sufficiently (Young's modulus can be reduced more sufficiently) and the drop resistance can be improved. From the above viewpoint, the content of the thermosetting compound (A) is preferably 10 parts by mass or more and 30 parts by mass or less, more preferably 10 parts by mass or more and 25 parts by mass or less.

[0164] The specific curing compound (B) makes the cured liquid crystal sealant more resistant to expansion and contraction. This not only improves resistance to impacts caused by dropping the liquid crystal panel, but also easily suppresses cracking of the cured sealant when subjected to pressure treatments on the liquid crystal display panel containing the sealant. In particular, if the curing compound shown in general formula (2) is used as the specific curing compound (B), the effect of making the cured material more resistant to expansion and contraction is even more pronounced.

[0165] When the total mass of the curable resin is set to 100 parts by mass, the content of the specific curable compound (B) is preferably 40 parts by mass or more and 90 parts by mass or less. If the content of the specific curable compound (B) is 40 parts by mass or more, the flexibility can be improved more sufficiently (Young's modulus can be reduced more sufficiently), thus improving the resistance to impacts caused by drops of the liquid crystal panel, and further suppressing cracking of the cured sealant during pressure treatment of the liquid crystal display panel. If the content of the specific curable compound (B) is 90 parts by mass or less, the moisture resistance of the cured product can be improved, and the display characteristics of the liquid crystal panel can be further improved. From the above viewpoint, the content of the specific curable compound (B) is preferably 50 parts by mass or more and 80 parts by mass or less.

[0166] Regarding other curing compounds (C), for example, photocurable compounds can be used to impart photocurability to the liquid crystal sealant. Furthermore, various physical properties of the liquid crystal sealant can be adjusted by selecting other curing compounds (C).

[0167] When the total mass of the curable resin is set to 100 parts by mass, the content of other curable compounds (C) is preferably 0 parts by mass or more and less than 50 parts by mass, more preferably 5 parts by mass or more and less than 40 parts by mass.

[0168] Furthermore, according to the present invention, curable compounds containing one (meth)acrylyl group per molecule are easily soluble in liquid crystals, which can easily cause liquid crystal contamination. Therefore, from the viewpoint of suppressing liquid crystal contamination, when the total mass of the curable resin is set to 100 parts by mass, the content of the curable compound containing one (meth)acrylyl group per molecule is preferably less than 10 parts by mass, more preferably less than 5 parts by mass, even more preferably less than 1 part by mass, and particularly preferably less than 0.1 parts by mass. The lower limit of the above-mentioned content of the curable compound containing one (meth)acrylyl group per molecule can be set to 0 parts by mass.

[0169] Some epoxy (meth)acrylates (D) can improve the adhesion of the cured sealant to the substrate.

[0170] Furthermore, while partial epoxy (meth)acrylate (D) can improve the adhesion of the cured product, it does not significantly improve its flexibility. Therefore, from the viewpoint of further improving the flexibility of the cured product, the lower the content of partial epoxy (meth)acrylate (D), the better. Based on this viewpoint, when the total mass of the cured resin is set to 100 parts by mass, the content of partial epoxy (meth)acrylate (D) is preferably less than 10 parts by mass, more preferably less than 5 parts by mass, even more preferably less than 1 part by mass, and particularly preferably less than 0.1 parts by mass. The lower limit of the above-mentioned content of partial epoxy (meth)acrylate (D) can be set to 0 parts by mass.

[0171] The thermosetting agent (E) is a hydrophilic thermosetting agent with a water solubility of 5 g / 100 g or less at 20°C. By ensuring that the thermosetting agent (E) has a solubility of 5 g / 100 g or less, the formation of bright spots (rough spots) caused by the attraction of the thermosetting agent by moisture in the liquid crystal during heat curing can be suppressed. From this perspective, the solubility is more preferably 3 g / 100 g or less, and even more preferably less than 1 g / 100 g. The lower limit of the solubility is not particularly limited and can be set to 3 g / 100 g or more.

[0172] The aforementioned hydrophilic thermosetting agent (E) is preferably an imidazole-based latent heat curing agent, an amine adduct-based latent heat curing agent, or a polyamine-based latent heat curing agent. These thermosetting agents are less likely to leach into the liquid crystal, and can be considered to more effectively suppress the formation of bright spots (roughness). From the viewpoint of more effectively suppressing the formation of bright spots (roughness), the aforementioned hydrophilic thermosetting agent (E) is preferably a polyamine-based latent heat curing agent.

[0173] From the viewpoint of improving the viscosity stability of the thermosetting resin composition without compromising the moisture resistance of the cured product, the melting point of the above-mentioned hydrophilic thermosetting agent (E) is preferably 50°C or higher and 250°C or lower, more preferably 70°C or higher and 150°C or lower, and even more preferably 80°C or higher and 120°C or lower.

[0174] Examples of imidazole-based heat-latent curing agents include 2-phenylimidazolium (melting point 137–147°C). Furthermore, commercially available imidazole-based heat-latent curing agents include 2P4MHZ-PW manufactured by Shikoku Chemical Industry Co., Ltd.

[0175] Amine adduct-based latent heat curing agents are latent heat curing agents composed of addition compounds obtained by reacting catalytically active amine compounds with any compound. Examples of amine adduct-based latent heat 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), all manufactured by Aminomo Chemical Co., Ltd.

[0176] Polyamine-based heat-latent curing agents are heat-latent curing agents with polymer structures obtained by reacting amines with epoxy resins. Examples include ADK HARDENEREH 4339S (softening point 120-130°C) manufactured by Adicon Corporation and ADK HARDENEREH 4357S (softening point 73-83°C) manufactured by Adicon Corporation.

[0177] When the total mass of the thermosetting compound (A) is set to 100 parts by mass, the content of the hydrophilic thermosetting agent (E) is preferably 10 parts by mass or more and 200 parts by mass or less, more preferably 50 parts by mass or more and 160 parts by mass or less, and even more preferably 70 parts by mass or more and 120 parts by mass or less. If the content of the thermosetting agent (E) is 10 parts by mass or more, the curability of the thermosetting compound (A) is easily improved. If the content of the hydrophilic thermosetting agent (E) is 200 parts by mass or less, it is easier to suppress the generation of bright spots (rough spots) caused by the hydrophilic thermosetting agent (E) seeping into the liquid crystal.

[0178] Photopolymerization initiator (F) enables specific curable compounds (B), other curable compounds (C), and some photocurable components such as epoxy (meth)acrylates (D) to begin curing (polymerization).

[0179] When the total mass of the photocurable compound (e.g., the aforementioned partial epoxy (meth)acrylate (D), specific curable compound (B), and other curable compound (C)) is set to 100 parts by mass, the content of the photopolymerization initiator (F) is preferably 0.01 parts by mass or more and 10 parts by mass or less. If the above-mentioned content of the photopolymerization initiator (F) is 0.01 parts by mass or more, the curability of the sealant is easily improved. If the above-mentioned content of the photopolymerization initiator (F) is 10 parts by mass or less, it is easier to suppress liquid crystal contamination caused by the dissolution of the photopolymerization initiator (F) into the liquid crystal. The above-mentioned content of the photopolymerization initiator (F) is more preferably 0.1 parts by mass or more and 5 parts by mass or less, further preferably 0.1 parts by mass or more and 3 parts by mass or less, and particularly more preferably 0.1 parts by mass or more and 2.5 parts by mass or less.

[0180] In addition to imparting predetermined hardness and linear expansion to the cured material, inorganic fillers (G) also inhibit the penetration of moisture and other substances through the interior of the cured material, thereby further reducing the moisture permeability of the cured material.

[0181] When the total mass of the curable resin is set to 100 parts by mass, the content of the inorganic filler (G) is preferably 10 parts by mass or more and 60 parts by mass or less, more preferably 20 parts by mass or more and 55 parts by mass or less, even more preferably 20 parts by mass or more and 50 parts by mass or less, and particularly preferably 20 parts by mass or more and 30 parts by mass or less. The higher the content of the inorganic filler (G) mentioned above, the more the moisture permeability of the cured product can be reduced. On the other hand, by keeping the content of the inorganic filler (G) not too high, it is possible to sufficiently ensure resistance to impacts caused by the drop of the liquid crystal display panel, etc., to suppress sealant leakage, and to improve coatability. From the viewpoint of achieving a balance of these, the content of the inorganic filler (G) is preferably set within the above range.

[0182] The liquid crystal sealant disclosed herein may also contain: the above-mentioned thermal free radical generator, organic microparticles, coupling agents such as silane coupling agents, ion scavengers, ion exchangers, leveling agents, pigments, dyes, sensitizers, plasticizers, and defoamers, etc.

[0183] When the total mass of the sealant is set to 100 parts by mass, the content of the aforementioned thermal free radical polymerization initiator is preferably between 0.01 parts by mass and 5.0 parts by mass. Setting the content of the thermal free radical polymerization initiator to 0.01 parts by mass or more further improves the thermosetting properties of the sealant. Setting the content of the thermal free radical polymerization initiator to 5.0 parts by mass or more further improves the dispensing stability of the sealant.

[0184] When the total mass of the sealant is set to 100 parts by mass, the content of the aforementioned organic microparticles is preferably between 5 parts by mass and 17 parts by mass. If the content of the organic microparticles is 5 parts by mass or more, the adhesion strength between the cured product and the substrate can be further improved. On the other hand, if the content of the organic microparticles is 17 parts by mass or less, the amount of other components (such as curable resin) becomes sufficiently large, which can further improve the strength of the cured product.

[0185] When the total mass of the sealant is set to 100 parts by mass, the content of the silane coupling agent is preferably 0.01 parts by mass or more and 5 parts by mass or less. If the content of the silane coupling agent is 0.01 parts by mass or more, the adhesion strength between the cured product and the substrate can be further improved.

[0186] When the total mass of the sealant is set to 100 parts by mass, the total amount of the other components mentioned above is preferably 0.1 parts by mass or more and 50 parts by mass or less. If the total amount of the other components is less than 50 parts by mass, the viscosity of the sealant is less likely to increase excessively, and the coating stability of the sealant is less likely to be compromised.

[0187] 2-1-3. Summary of the First Public Announcement

[0188] According to the first disclosure above, liquid crystal sealants such as the following can be provided.

[0189] [1] A liquid crystal sealant, wherein the cured product has a Young's modulus of 0.5 GPa or more and less than 3.0 GPa as measured at 23°C, the liquid crystal sealant comprising: a thermosetting compound (A) having an epoxy group in its molecule, and a thermosetting agent (E),

[0190] Among them, the above-mentioned thermosetting agent (E) is a thermosetting agent with a water solubility of less than 5g / 100g at 20°C.

[0191] [2] As described in [1], the liquid crystal sealant, wherein the above-mentioned thermosetting agent (E) is at least one thermosetting agent selected from the group consisting of imidazole-based thermosetting agents, amine adduct-based thermosetting agents and polyamine-based thermosetting agents.

[0192] [3] As described in [1] or [2], the liquid crystal sealant is heated at 120°C while the storage elastic modulus (G') and loss elastic modulus (G”) are measured using a dynamic viscoelasticity measuring device (rheometer), and the time until G' and G” become consistent is 450 seconds or less.

[0193] [4] The liquid crystal sealant described in any of [1] to [3] contains: a curable compound (B) with a characteristic ratio of 4.70 or less, a Tg of 250°C or more and 340°C or less, and a weight-average molecular weight (Mw) of 1000 or more.

[0194] [5] As described in [4], the liquid crystal sealant, wherein the curable compound (B) is a compound represented by general formula (1).

[0195] [Chemistry 4]

[0196]

[0197] (In general formula (1), R1 represents a divalent residue derived from a polycyclic epoxy compound; R2 independently represents a divalent structure obtained by opening a cyclic lactone; R3 independently represents a straight-chain or branched alkylene group having 1 or more carbon atoms and 6 or fewer carbon atoms; R4 independently represents a hydrogen atom or a methyl group).

[0198] [6] The liquid crystal sealant as described in [4] or [5], wherein the content of the curing compound (B) is 40 parts by mass or more and 90 parts by mass or less relative to 100 parts by mass of the curing resin.

[0199] [7] The liquid crystal sealant described in any of [1] to [6] contains a curable resin and an inorganic filler (G),

[0200] The content of the inorganic filler (G) is 20 parts by mass or more and 55 parts by mass or less, relative to 100 parts by mass of the curable resin.

[0201] [8] The liquid crystal sealant described in any of [1] to [7] has a moisture permeability of less than 50 g / m³ for a cured product with a thickness of 0.6 mm at 60°C and 90% Rh. 2 .

[0202] 2-2. Second Publication

[0203] 2-2-1. Issues covered in the second disclosure

[0204] Furthermore, as described in Patent Documents 1 to 5, various studies have been conducted on sealants with improved post-curing flexibility in order to improve resistance to impacts caused by drops, etc. Here, depending on the type of liquid crystal display panel, sometimes it is necessary to further improve the flexibility of the sealant to cope with bending at smaller curvatures. On the other hand, according to the present inventors' new insights, if the post-curing flexibility (elongation) of the sealant is increased, moisture permeability increases, which can sometimes lead to a decrease in the long-term reliability of the liquid crystal.

[0205] The second disclosure of this specification was made in view of the above-mentioned problems, and its object is to provide a liquid crystal sealant with high flexibility and low moisture permeability in the cured material, a method for manufacturing a liquid crystal display panel using the liquid crystal sealant, and a liquid crystal display panel manufactured using the liquid crystal sealant.

[0206] 2-2-2. Instructions for Liquid Crystal Sealant

[0207] The second disclosure of this specification relates to liquid crystal sealants with high flexibility and low moisture permeability after curing.

[0208] The cured sealant exhibits an elongation of over 30% at 23°C, and a 0.6mm thick cured sealant has a moisture permeability of less than 50g / m³ at 60°C and 90% RH. 2 .

[0209] The elongation rate mentioned above is specifically the elongation rate measured according to the following method.

[0210] Apply the sealant to the release paper to a thickness of 100 μm using an applicator. Then, place the applied sealant into a nitrogen purging container, purge with nitrogen for 5 minutes, and irradiate with 3000 mJ / cm² gas. 2 The light (corrected by a 365nm wavelength sensor) is then heated at 120°C for 1 hour to create a cured film.

[0211] After the obtained cured film was cut into strips (150 mm long and 10 mm wide), a tensile test was performed using an Autograph tensile testing machine (Shimadzu Corporation, AG-X) at room temperature (23°C) at a test speed of 10 mm / min. The elongation was calculated from the distance when the stress decreased by more than 80% from the yield point.

[0212] The aforementioned moisture permeability is specifically the elongation measured according to the following method.

[0213] Apply the sealant to the release paper to a thickness of 300 μm using an applicator. Then, place the applied sealant into a nitrogen purging container, purge with nitrogen for 5 minutes, and irradiate with 3000 mJ / cm² gas. 2 The light (corrected by a 365nm wavelength sensor) is then heated at 120°C for 1 hour to create a cured film.

[0214] Two cured films were placed inside an aluminum cup containing anhydrous calcium chloride as a desiccant. An aluminum ring was then placed on top and tightened with screws. The initial weight of the entire aluminum cup was measured. The cup was then placed in a thermostatic bath set to 60°C and 90% RH for 24 hours. Afterward, the cup was removed and its weight measured. The moisture permeability was calculated using the obtained weight value in the following formula.

[0215] Calculation formula:

[0216] Moisture permeability = (Weight after test - Weight before test) × Film thickness / (Film area × 100)

[0217] The sealant with the above properties can be formulated by various methods. For example, the sealant can be endowed with the above properties by using a flexible compound having an aromatic ring in its molecule, or by using the specific curing compound (B) mentioned above.

[0218] 2-2-3. Combinations of materials used in the second disclosure, etc.

[0219] The liquid crystal sealant disclosed in the second disclosure can widely utilize the aforementioned thermosetting compounds (A) having two or more epoxy groups within their molecules, specific curing compounds (B), other curing compounds (C), partially epoxy (meth)acrylates (D), thermosetting agents (E), photopolymerization initiators (F), inorganic fillers (G), and other materials. In this case, as long as the elongation of the cured product measured at 23°C is 30% or more, and the moisture permeability of a 0.6 mm thick cured product at 60°C and 90% Rh is less than 50 g / m³, it is acceptable. 2 The appropriate type of resin can be selected.

[0220] Thermosetting compound (A) can adjust various physical properties of liquid crystal sealants.

[0221] When the total mass of the curable resin is set to 100 parts by mass, the content of the thermosetting compound (A) is preferably 3 parts by mass or more and 30 parts by mass or less. If the content of the thermosetting compound (A) is 3 parts by mass or more, the moisture permeability of the cured product can be further reduced, and the display characteristics of the obtained liquid crystal panel can be improved. If the content of the thermosetting compound (A) is 30 parts by mass or less, the tensile strength and flexibility of the cured product can be improved more sufficiently. From the above viewpoint, the content of the thermosetting compound (A) is preferably 10 parts by mass or more and 30 parts by mass or less, more preferably 10 parts by mass or more and 25 parts by mass or less.

[0222] The specific curing compound (B) works in conjunction with the sealant to achieve a molecular coiled and stretched state, thereby making the sealant easier to stretch and expand, improving the stretchability and flexibility of the cured product, and making it less likely for the cured product to peel off or deform when the substrate is bent at a smaller curvature. In particular, if the curing compound shown in general formula (2) is used as the specific curing compound (B), the effect of making the cured product easier to stretch and expand is even more obvious.

[0223] When the total mass of the curable resin is set to 100 parts by mass, the content of the specific curable compound (B) is preferably 40 parts by mass or more and 90 parts by mass or less. If the content of the specific curable compound (B) is 40 parts by mass or more, the tensile strength and flexibility of the cured material can be improved more sufficiently. If the content of the specific curable compound (B) is 90 parts by mass or less, the moisture resistance of the cured material can be further improved, and the display characteristics of the liquid crystal panel can be further improved. From the above viewpoint, the content of the specific curable compound (B) is preferably 50 parts by mass or more and 80 parts by mass or less.

[0224] Regarding other curing compounds (C), for example, photocurable compounds can be used to impart photocurability to the liquid crystal sealant. Furthermore, various physical properties of the liquid crystal sealant can be adjusted by selecting other curing compounds (C).

[0225] When the total mass of the curable resin is set to 100 parts by mass, the content of other curable compounds (C) is preferably 0 parts by mass or more and less than 50 parts by mass, more preferably 5 parts by mass or more and less than 40 parts by mass.

[0226] Furthermore, according to the present invention, curable compounds containing one (meth)acrylyl group per molecule are easily soluble in liquid crystals, which can easily cause liquid crystal contamination. Therefore, from the viewpoint of suppressing liquid crystal contamination, when the total mass of the curable resin is set to 100 parts by mass, the content of the curable compound containing one (meth)acrylyl group per molecule is preferably less than 10 parts by mass, more preferably less than 5 parts by mass, even more preferably less than 1 part by mass, and particularly preferably less than 0.1 parts by mass. The lower limit of the above-mentioned content of the curable compound containing one (meth)acrylyl group per molecule can be set to 0 parts by mass.

[0227] Some epoxy (meth)acrylates (D) can improve the adhesion of the cured sealant to the substrate.

[0228] Furthermore, while partial epoxy (meth)acrylate (D) can improve the adhesion of the cured product, it does not significantly improve its flexibility. Therefore, from the viewpoint of further improving the flexibility of the cured product, the lower the content of partial epoxy (meth)acrylate (D), the better. Based on this viewpoint, when the total mass of the cured resin is set to 100 parts by mass, the content of partial epoxy (meth)acrylate (D) is preferably less than 10 parts by mass, more preferably less than 5 parts by mass, even more preferably less than 1 part by mass, and particularly preferably less than 0.1 parts by mass. The lower limit of the above-mentioned content of partial epoxy (meth)acrylate (D) can be set to 0 parts by mass.

[0229] Thermosetting agent (E) can cure thermosetting compounds (A), other curing compounds (C), and some thermosetting components such as epoxy (meth)acrylates (D).

[0230] When the total mass of the thermosetting compound (A) is set to 100 parts by mass, the content of the thermosetting agent (E) is preferably 3 parts by mass or more and 75 parts by mass or less, more preferably 3 parts by mass or more and 50 parts by mass or less, and even more preferably 5 parts by mass or more and 40 parts by mass or less. If the above-mentioned content of the thermosetting agent (E) is 3 parts by mass or more, the curability of the thermosetting compound (A) is easily improved. If the above-mentioned content of the thermosetting agent (E) is 75 parts by mass or less, it is easier to suppress liquid crystal contamination caused by the dissolution of the thermosetting agent (E) into the liquid crystal.

[0231] Furthermore, in this disclosure, by using a hydrophobic thermosetting agent that satisfies the condition of having a water solubility of 5 g / 100 g or less at 20°C, the generation of bright spots (rough spots) caused during pressure treatment of the substrate can be suppressed, which is the same as in the first disclosure. Moreover, from the viewpoint of suppressing the exudation of the thermosetting agent (E) from the liquid crystal during heat curing, when the aforementioned liquid crystal sealant at 25°C is heated to 120°C, the time until G' and G” become aligned is preferably 450 seconds or less, more preferably 440 seconds or less, and even more preferably 430 seconds or less, which is also the same as in the first disclosure.

[0232] Photopolymerization initiator (F) enables specific curable compounds (B), other curable compounds (C), and some photocurable components such as epoxy (meth)acrylates (D) to begin curing (polymerization).

[0233] When the total mass of the photocurable compound (e.g., the aforementioned partial epoxy (meth)acrylate (D), specific curable compound (B), and other curable compound (C)) is set to 100 parts by mass, the amount of photopolymerization initiator (F) is preferably 0.01 parts by mass or more and 10 parts by mass or less. If the aforementioned content of photopolymerization initiator (F) is 0.01 parts by mass or more, the curability of the sealant is easily improved. If the aforementioned content of photopolymerization initiator (F) is 10 parts by mass or less, liquid crystal contamination caused by the dissolution of photopolymerization initiator (F) into the liquid crystal is more easily suppressed. The aforementioned content of photopolymerization initiator (F) is more preferably 0.1 parts by mass or more and 5 parts by mass or less, further preferably 0.1 parts by mass or more and 3 parts by mass or less, and particularly more preferably 0.1 parts by mass or more and 2.5 parts by mass or less.

[0234] In addition to imparting predetermined hardness and linear expansion to the cured material, inorganic fillers (G) also inhibit the penetration of moisture and other substances through the interior of the cured material, thereby further reducing the moisture permeability of the cured material.

[0235] When the total mass of the curable resin is set to 100 parts by mass, the content of the inorganic filler (G) is preferably 30 parts by mass or more and 500 parts by mass or less, more preferably 50 parts by mass or more and 250 parts by mass or less, even more preferably 70 parts by mass or more and 200 parts by mass or less, and particularly preferably 100 parts by mass or more and 200 parts by mass or less. The higher the content of the inorganic filler (G) mentioned above, the more the moisture permeability of the cured product is reduced. On the other hand, keeping the content of the inorganic filler (G) not too high ensures the tensile strength and flexibility of the cured product more adequately. From the viewpoint of achieving a balance between these, the content of the inorganic filler (G) is preferably set within the above range.

[0236] The liquid crystal sealant disclosed herein may also contain: the above-mentioned thermal free radical generator, organic microparticles, coupling agents such as silane coupling agents, ion scavengers, ion exchangers, leveling agents, pigments, dyes, sensitizers, plasticizers, and defoamers, etc.

[0237] When the total mass of the sealant is set to 100 parts by weight, the content of the aforementioned thermal free radical polymerization initiator is preferably between 0.01 parts by weight and 5.0 parts by weight. Setting the content of the thermal free radical polymerization initiator to 0.01 parts by weight or more further improves the thermosetting properties of the sealant. Setting the content of the thermal free radical polymerization initiator to 5.0 parts by weight or less further improves the dispensing stability of the sealant.

[0238] When the total mass of the sealant is set to 100 parts by mass, the content of the aforementioned organic microparticles is preferably between 5 parts by mass and 17 parts by mass. If the content of the organic microparticles is 5 parts by mass or more, the adhesion strength between the cured product and the substrate can be further improved. On the other hand, if the content of the organic microparticles is 17 parts by mass or less, the amount of other components (such as curable resin) becomes sufficiently large, which can further improve the strength of the cured product.

[0239] When the total mass of the sealant is set to 100 parts by mass, the content of the silane coupling agent is preferably 0.01 parts by mass or more and 5 parts by mass or less. If the content of the silane coupling agent is 0.01 parts by mass or more, the adhesion strength between the cured product and the substrate can be further improved.

[0240] When the total mass of the sealant is set to 100 parts by mass, the total amount of other components is preferably between 0.1 parts by mass and 50 parts by mass. If the total amount of other components is less than 50 parts by mass, the viscosity of the sealant is less likely to increase excessively, and the coating stability of the sealant is less likely to be compromised.

[0241] 2-2-4. Summary of the Second Publication

[0242] According to the second disclosure above, liquid crystal sealants such as the following can be provided.

[0243] [1] A liquid crystal sealant, wherein the elongation of the cured product at 23°C is more than 30%, and the moisture permeability of a 0.6 mm thick cured product at 60°C and 90% Rh is less than 50 g / m². 2 .

[0244] [2] As described in [1], the liquid crystal sealant contains a curable resin.

[0245] Compared to 100 parts by weight of the above-mentioned curable resin, the amount of epoxy (meth)acrylate (A) is less than 10 parts by weight.

[0246] [3] The liquid crystal sealant as described in [1] or [2] contains: a curable compound (B) with a characteristic ratio of 4.70 or less, a Tg of 250°C or more and 340°C or less, and a weight-average molecular weight (Mw) of 1000 or more.

[0247] [4] As described in [3], the liquid crystal sealant, wherein the curable compound (B) is a compound represented by general formula (2).

[0248] [Chemistry 5]

[0249]

[0250] (In general formula (1), R1 represents a divalent residue derived from a polycyclic epoxy compound; R2 independently represents a divalent structure obtained by opening a cyclic lactone; R3 independently represents a straight-chain or branched alkylene group having 1 or more carbon atoms and 6 or fewer carbon atoms; R4 independently represents a hydrogen atom or a methyl group).

[0251] [5] The liquid crystal sealant described in [4] contains a curable resin, wherein the content of the curable compound (B) represented by general formula (1) is 40 parts by mass or more and 90 parts by mass or less relative to 100 parts by mass of the curable resin described above.

[0252] [6] The liquid crystal sealant described in any of [1] to [5] contains: a thermosetting compound having an epoxy group in the molecule (except for some epoxy (meth)acrylates) (A) and a thermosetting agent (E).

[0253] [7] As described in [6], the liquid crystal sealant wherein the above-mentioned thermosetting agent (E) is at least one thermosetting agent selected from the group consisting of dihydrazide-based thermosetting agents, imidazole-based thermosetting agents, amine adduct-based thermosetting agents and polyamine-based thermosetting agents.

[0254] [8] Liquid crystal sealant as described in [6] or [7], wherein the above-mentioned thermosetting compound (A) is a thermosetting compound having a bisphenol F backbone in the molecule.

[0255] [9] The liquid crystal sealant described in any of [1] to [8] contains a curable resin and an inorganic filler (G),

[0256] The content of inorganic filler (G) is 50 parts by mass or more and 250 parts by mass or less, relative to 100 parts by mass of the aforementioned curable resin.

[0257] 3. Liquid crystal display panel and its manufacturing method

[0258] Another embodiment of the present invention relates to a liquid crystal display panel comprising: a pair of substrates (a display substrate and a counter substrate) each having an alignment film; a frame-shaped sealing member disposed between the alignment films of the pair of substrates; and a liquid crystal layer filling a space between the pair of substrates surrounded by the sealing member. The sealing member of the liquid crystal display panel is a cured product of the sealant (liquid crystal sealant) disclosed above.

[0259] 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 PMMA.

[0260] On the surface of the display substrate or the opposing substrate, for example, matrix TFTs, color filters, black matrices, etc., may also be disposed. An alignment film may be further disposed on the surface of the display substrate or the opposing substrate. The alignment film contains known organic or inorganic alignment agents.

[0261] The liquid crystal display panel is manufactured using the liquid crystal sealant of this invention. The manufacturing methods for liquid crystal display panels generally include liquid crystal drop-off and liquid crystal injection processes, but the liquid crystal display panel of this invention is preferably manufactured using the liquid crystal drop-off process.

[0262] Methods for manufacturing liquid crystal display panels using liquid crystal dispensing technology include:

[0263] 1) For a pair of substrates each having an alignment film, the above-mentioned liquid crystal sealant is applied to the alignment film of one of the substrates to form a sealing pattern.

[0264] 2) The step of dropping liquid crystal onto the area surrounded by the sealing pattern on one of the substrates, or onto another substrate, while the sealing pattern is not cured;

[0265] 3) The step of overlapping one substrate with another substrate through a sealing pattern; and

[0266] 4) Steps to cure the sealing pattern.

[0267] 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 gel point. Therefore, in step 2), in order to inhibit the dissolution of the liquid crystal sealant into the liquid crystal, the sealing pattern can also be subjected to light irradiation or heating to make it semi-cured. One of the substrates and the other substrate are a display substrate or a counter substrate, respectively.

[0268] In step 4), curing can be performed using light irradiation followed by curing using heat. Curing using light irradiation allows the liquid crystal sealant to cure quickly, thus suppressing its dissolution in the liquid crystal. By combining curing using light irradiation and curing using heat, damage to the liquid crystal layer caused by light can be reduced compared to curing using only light irradiation.

[0269] The irradiated light can be appropriately selected based on the type of photopolymerization initiator (F) 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. The reason is that light of this wavelength causes less damage to the liquid crystal material and the driving electrode. Known light sources that emit ultraviolet or visible light can be used for irradiation. When irradiating with visible light, examples such as high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, xenon lamps, and fluorescent lamps can be used.

[0270] The light irradiation energy is any energy sufficient to cure a specific curable compound (B). The curing time varies depending on the composition of the liquid crystal sealant, and is, for example, around 10 minutes.

[0271] The heat curing temperature varies depending on the composition of the sealant and can be set to, for example, 120°C. The heat curing time is about 2 hours. For example, when the low-temperature curing property is improved in the first disclosure, it can be set to about 50 minutes to 1.5 hours.

[0272] Furthermore, after step 4), a step 5) of applying pressure to the substrate may also be included. This pressure treatment can be, for example, a process of thinning the substrate by grinding. The conditions for the pressure treatment are not particularly limited; for example, it can be performed 5 times with a load of 80N for 7 minutes.

[0273] Example

[0274] The present invention will be described in detail with reference to embodiments, but the present invention is not limited to these embodiments.

[0275] [Materials used in the examples]

[0276] 1. Synthesis of a specific curable compound (B)

[0277] <Synthesis Example 1: Curable Compound (B-1)>

[0278] (BisA type acrylic resin)

[0279] 116 g of hydroxyethyl acrylate, 0.2 g of p-methoxyphenol (as a polymerization inhibitor), 148 g of phthalic anhydride, and 342 g of ε-caprolactone were charged into a reaction flask. Dry air was introduced, and the reaction was carried out under reflux and stirring at 90 °C for 6 hours. Next, 170 g of bisphenol A diglycidyl ether was added, and the reaction was again carried out under reflux and stirring at 90 °C for 6 hours. The obtained compound was washed 20 times with ultrapure water to obtain the cured compound B-1.

[0280] <Synthesis Example 2: Curable Compound (B-2)>

[0281] (Bis type A methacrylic resin)

[0282] 130 g of hydroxyethyl methacrylate, 0.2 g of p-methoxyphenol (as a polymerization inhibitor), 148 g of phthalic anhydride, and 342 g of ε-caprolactone were charged into a reaction flask. Dry air was introduced, and the reaction was carried out under reflux and stirring at 90 °C for 6 hours. Next, 170 g of bisphenol A diglycidyl ether was added, and the reaction was again carried out under reflux and stirring at 90 °C for 6 hours. The obtained compound was washed 20 times with ultrapure water to obtain the cured compound B-2.

[0283] <Synthesis Example 3: Curable Compound (B-3)>

[0284] (Bis F type acrylic resin)

[0285] 116 g of hydroxyethyl acrylate, 0.2 g of p-methoxyphenol (as a polymerization inhibitor), 148 g of phthalic anhydride, and 342 g of ε-caprolactone were added to a reaction flask. Dry air was introduced, and the reaction was carried out under reflux and stirring at 90 °C for 6 hours. Next, 156 g of bisphenol F diglycidyl ether was added, and the reaction was again carried out under reflux and stirring at 90 °C for 6 hours. The obtained compound was washed 20 times with ultrapure water to obtain the cured compound B-3.

[0286] <Synthesis Example 4: Curable Compound (B-4)>

[0287] (Bis F type methacrylic resin)

[0288] 130 g of hydroxyethyl methacrylate, 0.2 g of p-methoxyphenol (as a polymerization inhibitor), 148 g of phthalic anhydride, and 342 g of ε-caprolactone were charged into a reaction flask. Dry air was introduced, and the reaction was carried out under reflux and stirring at 90 °C for 6 hours. Next, 156 g of bisphenol F diglycidyl ether was added, and the reaction was again carried out under reflux and stirring at 90 °C for 6 hours. The obtained compound was washed 20 times with ultrapure water to obtain the cured compound B-4.

[0289] 2. Preparation of other materials

[0290] The following materials were used as other materials.

[0291] 2-1. Curing Resin

[0292] 2-1-1. Thermosetting compounds with intramolecular epoxy groups (A)

[0293] • Thermosetting compound (A-1): Propylene oxide modified bisphenol A type epoxy resin [manufactured by ADEKA RESIN Co., Ltd., ADEKA RESIN EP-4000S (“ADEKA RESIN” and “ADEKA RESIN EP” are registered trademarks of the company)]

[0294] • Thermosetting compound (A-2): Bisphenol F type epoxy resin (manufactured by ADEKA Corporation, ADEKA RESINEP-4901)

[0295] • Thermosetting compound (A-3): Rubber-modified (EPR-modified) bisphenol F epoxy resin (manufactured by ADEKA RESIN EPR-4030)

[0296] 2-1-2. Other curable compounds (C)

[0297] • Other curing compounds (C-1): Bisphenol A type epoxy acrylate [manufactured by Daicel-Allnex Co., Ltd., EBECRYL 3700 (“EBECRYL” is a registered trademark of the company)]

[0298] • Curable compound (C-2): 2-Hydroxybutyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., Lightester Hob)

[0299] 2-1-3. Partially epoxy (meth)acrylates (D)

[0300] • Made by Daicel-Zhenxin Co., Ltd., KRM 8287 (“KRM” is a registered trademark of the company)

[0301] 2-2. Thermosetting agent

[0302] 2-2-1. Thermosetting agent (E)

[0303] • Thermosetting agent (E-1): Polyamine-based latent heat curing agent [Manufactured by Adico Corporation, EH-4357S (Solubility: less than 1g / 100g)]

[0304] • Thermosetting agent (E-2): Imidazole-based latent heat curing agent [Manufactured by Adico Corporation, EH-4344S (Solubility: ≥1g / 100g and ≤5g / 100g)]

[0305] • Thermosetting agent (E-3): Adipic acid dihydrazide-based latent heat curing agent [manufactured by Nippon Seika Co., Ltd., adipic acid dihydrazide (ADH) (solubility: 9g / 100g)]

[0306] • Thermosetting agent (E-4): Diazidamide-based latent heat curing agent [manufactured by Nippon Seika Co., Ltd., diazidamide malonate (MDH) (solubility 10g / 100g)]

[0307] • Thermosetting agent (E-5): Amine adduct-based latent heat curing agent [Manufactured by Aminomoto Fine Technology Co., Ltd., AMICURE PN-50 (“AMICURE” is a registered trademark of Aminomoto Co., Ltd.)]

[0308] • Thermosetting agent (E-6): Diacylhydrazide-based latent heat curing agent (manufactured by Aminomoto Fine Technology Co., Ltd., AMICURE VDH)

[0309] In addition, the solubility of thermosetting agents (E-1) to (E-4) was determined according to the method shown below.

[0310] (Methods for determining solubility)

[0311] (Determination Method)

[0312] Add 100g of water and a predetermined amount of curing agent to a 300mL beaker. After mixing and stirring for 2 hours, determine whether the mixture is dissolved when it appears transparent. Then, gradually reduce the amount of thermosetting agent (E) added to the water while adding, mixing, and visually judging the mixture. The concentration of thermosetting agent (E) that is initially determined to be dissolved is set as the above-mentioned solubility.

[0313] 2-3. Photopolymerization initiator (F)

[0314] • Photopolymerization initiator (F-1): BASF, OXE-02

[0315] • Photopolymerization initiator (F-2): Manufactured by IGM Corporation, Omnipol-TX (“Omnipol” is a registered trademark of the company)

[0316] 2-4. Inorganic fillers (G)

[0317] • Silica particles: Manufactured by Admatechs Co., Ltd., SO-C1

[0318] 2-5. Other materials

[0319] • Thermal free radical generator (1): Water-soluble azo polymerization initiator (manufactured by Fujifilm and Wako Pure Chemical Industries, Ltd., V-501)

[0320] • Thermal free radical generator (2): Water-soluble azo polymerization initiator (manufactured by Fujifilm and Kazumitsu Chemical Co., Ltd., VA-086)

[0321] • Particulate polymer: Polymethacrylate-based organic microparticles [manufactured by AICA Industries, Ltd., ZEFIAC F351 (“ZEFIAC” is a registered trademark of ZEON Corporation, Japan)]

[0322] • Silane coupling agent: Shin-Etsu Chemical Co., Ltd., KBM 403

[0323] 2-6. Physical properties of various materials

[0324] The weight-average molecular weight (Mw) of each of the above resin components was determined using gel permeation chromatography (GPC).

[0325] In addition, according to JIS K 7236 (2001), the epoxy equivalent of the resin component with epoxy groups is determined.

[0326] In addition, the characteristic ratios and glass transition temperatures (Tg) of the above resin components were determined using the Bicerano method with the calculation software Materials Studio 2020 Synthia.

[0327] The above physical properties are shown in Table 1.

[0328] [Table 1]

[0329]

[0330] [Comparative Examples of Embodiments Relating to the First Disclosure]

[0331] 1-1. Preparation of sealant

[0332] Using a three-roll mill, 80 parts by weight of a thermosetting compound (A-1), 520 parts by weight of a curing compound (B-1), 60 parts by weight of another curing compound (C-1), 80 parts by weight of a thermosetting agent (E-1), 5 parts by weight of a photopolymerization initiator (F-1), 175 parts by weight of silica particles, 70 parts by weight of a microparticle polymer, and 10 parts by weight of a silane coupling agent are thoroughly mixed into a homogeneous solution to obtain a sealant (1).

[0333] Except for changing the types and amounts of materials used to those listed in Tables 2 to 4, the same procedure was followed to obtain sealant (2) to sealant (14).

[0334] The compositions of sealant (1) to sealant (14) are shown in Tables 2 to 4. Unless otherwise stated, all values ​​for each component are expressed in parts by mass.

[0335] 1-2. Evaluation

[0336] For the sealants (1) to (14) prepared above, Young's modulus, elongation at break, drop characteristics, moisture permeability, display characteristics, low-temperature curing properties and coatability are evaluated according to the following methods.

[0337] Young's Modulus

[0338] The obtained sealant was applied to release paper to a thickness of 100 μm using an applicator. Then, the applied sealant was placed in a nitrogen purging container, purged with nitrogen for 5 minutes, and irradiated with 3000 mJ / cm² gas. 2 The light (corrected by a 365nm wavelength sensor) is then heated at 120°C for 1 hour to create a cured film.

[0339] After the obtained cured film was cut into strips (150 mm long and 10 mm wide), a tensile test was performed using an Autograph tensile testing machine (Shimadzu Corporation, AG-X) at room temperature (23°C) at a test speed of 10 mm / min. The Young's modulus was calculated from the slope of stress and strain in the elastic region.

[0340] <Drop Characteristics>

[0341] On a 140mm × 70mm glass substrate (RT-DM88-PIN, manufactured by EHC) pre-formed with transparent electrodes and alignment films, the obtained sealant was applied using a dispensing machine (SHOTMASTER, manufactured by Musashi Engineering) to form a 135mm × 65mm quadrilateral sealing pattern (3500μm cross-sectional area). 2 ), serving as the main seal.

[0342] Next, using a dispensing machine, liquid crystal material (MLC-6609-000, manufactured by Merck) equivalent to the volume of the laminated panel is precisely dripped into the main sealing frame. Then, the paired glass substrates are laminated under reduced pressure, followed by open-atmosphere bonding. After holding the two laminated glass substrates in a light-shielding chamber for 1 minute, they are then irradiated with 3000 mJ / cm² light, with only the liquid crystal portion obscured by a substrate coated with a black matrix. 2 The liquid crystal display panel is obtained by heating the main seal with visible light (wavelength 370-450nm) for 1 hour at 120°C.

[0343] The obtained liquid crystal display panel was dropped from a height of 50mm. If no liquid crystal leakage occurred due to peeling or cracking of the panel unit, the drop test was repeated by raising the drop position by 50mm each time, with an upper limit of 500mm. The panel unit was visually observed after the test, and its drop characteristics were evaluated according to the following criteria.

[0344] ◎: No liquid crystal leakage caused by peeling or cracking of the cell was confirmed up to 500mm.

[0345] ○: Liquid crystal leakage was confirmed in the LCD panel at a height of 300mm or more but less than 500mm.

[0346] ×: Liquid crystal leakage was confirmed in the LCD panel at a height of less than 300mm.

[0347] <Moisture permeability>

[0348] The obtained sealant was applied to the release paper to a thickness of 300 μm using an applicator. Then, the applied sealant was placed in a nitrogen purging container, purged with nitrogen for 5 minutes, and irradiated with 3000 mJ / cm² gas. 2 The light (corrected by a 365nm wavelength sensor) is then heated at 120°C for 1 hour to create a cured film.

[0349] Two cured films were placed inside an aluminum cup containing anhydrous calcium chloride as a desiccant. An aluminum ring was then placed on top and tightened with screws. The initial weight of the entire aluminum cup was measured. The cup was then placed in a thermostatic bath set to 60°C and 90% RH for 24 hours. Afterward, the cup was removed and its weight measured. The obtained weight value was used to calculate the moisture permeability using the following formula.

[0350] Calculation formula:

[0351] Moisture permeability = (Weight after test - Weight before test) × Film thickness / (Film area × 100)

[0352] <Display characteristics (suppressing roughness)>

[0353] On a 40mm×45mm glass substrate (manufactured by EHC Corporation, RT-DM88-PIN) with a transparent electrode and alignment film already formed, the obtained sealant was applied using a dispensing machine (SHOTMASTER, manufactured by Musashi Engineering Co., Ltd.) to form a 35mm×35mm quadrilateral sealing pattern (cross-sectional area 3500μm) as the main seal. 2 ), and its surrounding 38mm×38mm quadrilateral sealing pattern.

[0354] Next, using a dispensing machine, liquid crystal material (Merck, MLC-7026-100) equivalent to the desired liquid crystal content of the liquid crystal display panel is precisely dripped into the frame of the main seal, and then left to stand for 100 minutes or 10 minutes. Then, the aforementioned glass substrate and its paired glass substrate are bonded together under a reduced pressure of 4 Pa, and then exposed to atmospheric pressure. After holding the two bonded glass substrates in a light-shielding chamber for 1 minute, the main seal is then masked using a substrate coated with a 36mm × 36mm quadrilateral black matrix. Under these conditions, the glass substrates are subjected to a pressure of 1 J / cm². 2 The glass substrates are irradiated with light of wavelength 370–450 nm. These substrates are then heated at 120°C for 1 hour to cure the main seal and obtain liquid crystal cells. Polarizing films are then adhered to both sides of the obtained liquid crystal cells to obtain a liquid crystal display panel. The obtained liquid crystal display panel is then subjected to a pressure treatment at 80 N for 10 minutes.

[0355] The display characteristics of the obtained LCD panels were evaluated according to the following criteria.

[0356] ◎: No bright spots (rough spots) were detected after 100 minutes and 10 minutes of standing.

[0357] ○: Although bright spots (rough spots) were observed after 100 minutes of standing, no bright spots (rough spots) were observed after 10 minutes of standing.

[0358] ×: Bright spots (rough spots) were observed after both 100 minutes and 10 minutes of standing.

[0359] <Low-temperature curing properties>

[0360] While measuring the storage modulus (G') and loss modulus (G”) using a dynamic viscoelasticity measuring device (rheometer), the sealant at 25°C was heated in a 120°C (constant temperature) environment. The time from the start of heating until G' and G” became consistent was measured.

[0361] The evaluation results of Young's modulus, drop characteristics, moisture permeability, display characteristics and coatability of sealants (1) to sealants (14) are shown in Tables 2 to 4. In addition, the tables show: the amount of thermosetting compound (A) with intramolecular epoxy groups relative to the total mass of cured resin (column “(A) amount / total cured resin”), the amount of a specific curable compound (B) relative to the total mass of cured resin (column “(B) amount / total cured resin”), and the amount of a portion of epoxy (meth)acrylate (D) relative to the total mass of cured resin contained in the liquid crystal sealant (column “(D) amount / total cured resin”).

[0362] [Table 2]

[0363]

[0364]

[0365] [Table 3]

[0366]

[0367] [Table 4]

[0368]

[0369] As shown in Tables 2 to 4, by using a liquid crystal sealant containing a thermosetting compound (A) with an intramolecular epoxy group having a Young's modulus of 0.5 GPa or more and less than 3.0 GPa as measured at 23°C, and a thermosetting agent (E), wherein the thermosetting agent (E) has a water solubility of 5 g / 100 g or less at 20°C, it is possible to suppress the generation of bright spots (rough spots) when pressure treatment is applied to the liquid crystal panel element.

[0370] [Comparative Examples of Embodiments Relating to the Second Disclosure]

[0371] 2-1. Preparation of sealant

[0372] Using a three-roll mill, 80 parts by weight of a thermosetting compound (A-1), 520 parts by weight of a curing compound (B-1), 120 parts by weight of another curing compound (C-1), 20 parts by weight of a thermosetting agent (E-5), 5 parts by weight of a photopolymerization initiator (F-1), 175 parts by weight of silica particles, 70 parts by weight of a microparticle polymer, and 10 parts by weight of a silane coupling agent are thoroughly mixed into a homogeneous solution to obtain a sealant (21).

[0373] Except for changing the types and amounts of materials used to those described in Tables 5 and 6, the same procedure was followed to obtain sealant (22) to sealant (33).

[0374] The compositions of sealant (21) to sealant (33) are shown in Tables 5 and 6. In addition, unless otherwise stated, all values ​​listed for each component are expressed as "parts by mass".

[0375] 2-2. Evaluation

[0376] For the sealants (21) to (33) prepared above, elongation, flexibility, moisture permeability and liquid crystal fouling were evaluated according to the following methods.

[0377] <Elongation>

[0378] The obtained sealant was applied to release paper to a thickness of 100 μm using an applicator. Then, the applied sealant was placed in a nitrogen purging container, purged with nitrogen for 5 minutes, and irradiated with 3000 mJ / cm² gas. 2 The light (corrected by a 365nm wavelength sensor) is then heated at 120°C for 1 hour to create a cured film.

[0379] After the obtained cured film was cut into strips (150 mm long and 10 mm wide), a tensile test was performed using an Autograph tensile testing machine (Shimadzu Corporation, AG-X) at room temperature (23°C) at a test speed of 10 mm / min. The elongation was calculated from the distance when the stress decreased by more than 80% from the yield point.

[0380] <Flexibility>

[0381] After cutting the obtained cured film into strips (50 mm long and 10 mm wide), bend them along a mandrel with a diameter of 1.0 mm or 1.5 mm and hold them for 10 seconds. Remove the cured film from the mandrel and let it rest on a flat surface for 1 minute. Then, visually observe the state of the cured film and evaluate its flexibility according to the following criteria.

[0382] ◎: No cracks or bending were found in the 1.0mm and 1.5mm diameter mandrels.

[0383] ○: Although bending and other deformations occurred on the 1.0mm diameter mandrel, no cracking or bending deformations occurred on the 1.5mm diameter mandrel.

[0384] △: Although the 1.5mm diameter mandrel did not crack, it showed deformation such as bending.

[0385] ×: Cracks appeared on the 1.5mm diameter mandrel.

[0386] <Moisture permeability>

[0387] The obtained sealant was applied to the release paper to a thickness of 300 μm using an applicator. Then, the applied sealant was placed in a nitrogen purging container, purged with nitrogen for 5 minutes, and irradiated with 3000 mJ / cm² gas. 2 The light (corrected by a 365nm wavelength sensor) is then heated at 120°C for 1 hour to create a cured film.

[0388] Two cured films were placed inside an aluminum cup containing anhydrous calcium chloride as a desiccant. An aluminum ring was then placed on top and tightened with screws. The initial weight of the entire aluminum cup was measured. The cup was then placed in a thermostatic bath set to 60°C and 90% RH for 24 hours. Afterward, the cup was removed and its weight measured. The obtained weight value was used to calculate the moisture permeability using the following formula.

[0389] Calculation formula:

[0390] Moisture permeability = (Weight after test - Weight before test) × Film thickness / (Film area × 100)

[0391] <Liquid Crystal Pollution>

[0392] Weigh 0.03 g of the obtained sealant and 0.3 g of liquid crystal (Merck, MLC-7026-100) into a 1 ml beaker and heat at 120 °C for 1 hour. Compare the nematic-isotropic liquid phase transition temperature (NI point) of the heated liquid crystal with the NI point of the uncontaminated liquid crystal before heating, and calculate the difference (ΔNI point). Furthermore, when using a liquid crystal sealant with low liquid crystal contamination, the absolute value of ΔNI point decreases.

[0393] Based on the obtained ΔNI point, the sealant is evaluated according to the following criteria.

[0394] 〇: ΔNI point is below 2.0℃

[0395] ×: ΔNI point is greater than 2.0℃

[0396] The evaluation results of elongation, flexibility, moisture permeability and liquid crystal fouling of sealants (22) to (33) are shown in Tables 5 and 6. In addition, the tables show: the amount of thermosetting compound (A) with intramolecular epoxy groups relative to the total mass of cured resin ("Amount of (A) / Total of Cured Resin" column), the amount of a specific curing compound (B) relative to the total mass of cured resin ("Amount of (B) / Total of Cured Resin" column), and the amount of a portion of epoxy (meth)acrylate (D) relative to the total mass of cured resin ("Amount of (D) / Total of Cured Resin" column).

[0397] [Table 5]

[0398]

[0399] [Table 6]

[0400]

[0401] As can be seen from Tables 5 and 6, the liquid crystal sealant according to the present invention can achieve both high flexibility and low moisture permeability.

[0402] This application claims priority to Japanese Applications No. 2021-046327, 2021-046329, and 2021-046333, all filed on March 19, 2021. The matters set forth in the description, claims, and abstract of those applications are incorporated herein by reference.

[0403] Industrial availability

[0404] This invention is very useful in applications for various liquid crystal display panels.

Claims

1. A liquid crystal sealant, wherein the cured product has a Young's modulus of 0.5 GPa or higher and less than 3.0 GPa as measured at 23°C. The liquid crystal sealant contains a curable resin and a thermosetting agent (E), wherein the curable resin contains: Thermosetting compounds (A) with intramolecular epoxy groups, and The curable compound (B) shown in formula (1) has a property ratio of 4.7 or less, a Tg of 250°C or more and 340°C or less, and a weight-average molecular weight Mw of 1000 or more. in, In equation (1), <R0 2 > is the root mean square of all possible distances between the ends of the polymer chain, L is the root mean square of the lengths of the constituent units of the polymer chain, and n is the number of constituent units. The thermosetting agent (E) is a thermosetting agent with a water solubility of less than 5g / 100g at 20°C.

2. The liquid crystal sealant as described in claim 1, wherein, The thermosetting agent (E) is at least one thermosetting agent selected from the group consisting of imidazole-based thermo-latentive curing agents, amine adduct-based thermo-latentive curing agents, and polyamine-based thermo-latentive curing agents.

3. The liquid crystal sealant as described in claim 1 or 2, wherein, While measuring the storage elastic modulus G' and loss elastic modulus G" using a dynamic viscoelasticity measuring device, i.e., a rheometer, the liquid crystal sealant at 25°C was heated to 120°C, and the time until G' and G" became consistent was less than 450 seconds.

4. The liquid crystal sealant as described in claim 1 or 2, wherein, The curable compound (B) is a compound represented by general formula (2). In general formula (2), R1 represents a divalent residue derived from a polycyclic epoxy compound; R2 independently represents a divalent structure obtained by opening a cyclic lactone; R3 independently represents a straight-chain or branched alkylene group with 1 or more carbon atoms and 6 or fewer carbon atoms; and R4 independently represents a hydrogen atom or a methyl group.

5. The liquid crystal sealant as described in claim 1 or 2, wherein, The content of the curing compound (B) is 40 parts by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the curing resin.

6. The liquid crystal sealant according to claim 1 or 2, further comprising an inorganic filler (G), wherein the content of the inorganic filler (G) is 20 parts by weight or more and 55 parts by weight or less relative to 100 parts by weight of the curable resin.

7. The liquid crystal sealant as described in claim 1 or 2, wherein the moisture permeability of a 0.6 mm thick cured product is less than 50 g / m³ at 60°C and 90% RH. 2 .

8. A method for manufacturing a liquid crystal display panel, comprising: For a pair of substrates each having an alignment film, the step of coating the liquid crystal sealant according to any one of claims 1 to 7 onto the alignment film of one of the substrates to form a sealing pattern; The step of dropping liquid crystal onto one of the substrates and within the area of ​​the sealing pattern, or onto another substrate, while the sealing pattern is not cured; The step of overlapping one of the substrates with the other substrate through the sealing pattern; as well as The step of curing the sealing pattern.

9. The method for manufacturing a liquid crystal display panel as described in claim 8, wherein, In the step of curing the sealing pattern, the sealing pattern is cured by irradiating it with light.

10. The method for manufacturing a liquid crystal display panel as described in claim 9, wherein, The light illuminating the sealing pattern includes light from the visible light region.

11. The method for manufacturing a liquid crystal display panel as described in claim 9 or 10, wherein, In the step of curing the sealing pattern, the sealing pattern after being exposed to light is further heated.

12. The method for manufacturing a liquid crystal display panel according to any one of claims 8 to 10, wherein after the step of curing the sealing pattern, a step of applying pressure to the substrate is performed.

13. A liquid crystal display panel, comprising: A pair of substrates, each having an alignment film; A frame-shaped sealing member disposed between the alignment films of the pair of substrates; and A liquid crystal layer, which fills the space between the pair of substrates surrounded by the sealing member. in, The sealing component is a cured product of the liquid crystal sealant according to any one of claims 1 to 7.

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