WO2013005692A1

WO2013005692A1 - Liquid crystal sealing material and liquid crystal display cell using same

Info

Publication number: WO2013005692A1
Application number: PCT/JP2012/066792
Authority: WO
Inventors: 英之太田; 栄一西原; 大輔今岡; 早紀吉田; 堅太菅原
Original assignee: 日本化薬株式会社
Priority date: 2011-07-03
Filing date: 2012-06-29
Publication date: 2013-01-10
Also published as: JP2013015645A; KR20140039314A; CN103649824A; CN103649824B; JP5748273B2; TW201319109A

Abstract

The purpose of the present invention is to provide a liquid crystal sealing material for use in a liquid crystal drop fill method. The sealing material can achieve a rapid thermal reaction, rarely contaminates a liquid crystal throughout the process, and exhibits excellent storage stability and excellent cured product properties such as moisture proof reliability. The liquid crystal sealing material is characterized by comprising (a) one or more curable resins selected from among epoxy resins, (meth)acrylated epoxy resins, and partially (meth)acrylated epoxy resins, each resin bearing active hydrogen in the molecule (with the proviso that the active hydrogen is exclusive of hydrogen contained in a hydroxyl group), and (b) a heat-curing agent.

Description

Liquid crystal sealant and liquid crystal display cell using the same

The present invention relates to a liquid crystal sealant having good curability by heat. More specifically, the present invention relates to a liquid crystal sealing agent having good curability by heat, excellent storage stability, and excellent moisture resistance of a cured product, and a liquid crystal display cell sealed with the cured product.

With the recent increase in size of liquid crystal display cells, a so-called liquid crystal dropping method with higher mass productivity has been proposed as a liquid crystal display cell manufacturing method (Patent Documents 1 and 2). Specifically, it is a method of manufacturing a liquid crystal display cell in which liquid crystal is sealed by dropping a liquid crystal inside a weir of a liquid crystal sealant formed on one substrate and then bonding the other substrate.

However, in the liquid crystal dropping method, the liquid crystal sealant in an uncured state comes into contact with the liquid crystal. At that time, the components of the liquid crystal sealant are dissolved (eluting) in the liquid crystal to reduce the resistance value of the liquid crystal, There is a problem that a display defect occurs.

In order to solve this problem, a photothermal combination type liquid crystal sealant for a liquid crystal dropping method is currently used and put into practical use (Patent Documents 3 and 4). The liquid crystal dropping method using the liquid crystal sealant is characterized in that the liquid crystal sealant sandwiched between the substrates is irradiated with light to be primarily cured and then heated to be secondarily cured. According to this method, the uncured liquid crystal sealant can be quickly cured by light, and dissolution (elution) of the liquid crystal sealant component into the liquid crystal can be suppressed. Furthermore, the problem of insufficient adhesive strength due to curing shrinkage at the time of photocuring occurs only by photocuring, but the photothermal combination type has an advantage that such problems can be solved by secondary curing by heating.

However, in recent years, with the miniaturization of liquid crystal display elements, a light shielding portion where the liquid crystal sealant is not exposed to light is generated due to the metal wiring part of the array substrate of the liquid crystal display element and the black matrix part of the color filter substrate. The defect problem is more serious than before. That is, the primary curing by the light becomes insufficient due to the presence of the light shielding part, and a large amount of uncured components remain in the liquid crystal sealant. When the process proceeds to the secondary curing step by heat in this state, the dissolution of the uncured component into the liquid crystal is accelerated by the heat, resulting in a display defect near the seal.

In order to solve this problem, various studies for improving thermal reactivity have been made. It is an attempt to suppress liquid crystal contamination by reacting a liquid crystal sealant that is not sufficiently cured by light in the light shielding portion from a low temperature. For example, Patent Documents 5 and 6 disclose a method using a thermal radical initiator. Patent Documents 7 to 9 disclose methods using polyvalent carboxylic acids as curing accelerators.

However, in general, a thermal radical initiator generates radicals little by little even at room temperature, and thus has a problem that the storage stability and work stability of the liquid crystal sealant are poor. In addition, a curing accelerator such as a polyvalent carboxylic acid acts as a catalyst, reacts itself, and is not taken into the cured product by a chemical bond. There is a problem of causing defects.

As described above, the development of liquid crystal sealants has been carried out very vigorously, but also has excellent thermal stability and good storage stability and low liquid crystal contamination. A liquid crystal sealant having the above has not been realized yet.

Japanese Unexamined Patent Publication No. 63-179323 JP-A-10-239694 Japanese Patent No. 3583326 JP 2004-61925 A Japanese Patent Application Laid-Open No. 2004-126211 JP 2009-8754 A International Publication No. 2007/138870 JP 2008-15155 A JP 2009-139922 A

The present invention relates to a liquid crystal sealant that is cured only by heating or by combined use of light and heat, and since the reaction by heat is fast, it is extremely low in contamination with liquid crystals throughout the process and has excellent storage stability and moisture resistance. The present invention proposes a liquid crystal sealant for a liquid crystal dropping method that is excellent in properties of cured products such as reliability.

As a result of intensive studies, the inventors have one or more selected from epoxy resins, (meth) acrylated epoxy resins, and partially (meth) acrylated epoxy resins having active hydrogen in the molecule. A liquid crystal sealing agent containing a curable resin (however, excluding hydrogen contained in a hydroxy group as active hydrogen) has excellent thermal reactivity, and as a result, liquid crystal contamination can be suppressed. The inventors have found that the storage stability is excellent and have completed the present invention.
That is, the present invention relates to the following 1) to 13). In addition, in this specification, about the component (a), "(a) 1 selected from the epoxy resin which has active hydrogen in a molecule | numerator, (meth) acrylated epoxy resin, and partial (meth) acrylated epoxy resin" In order to avoid the trouble of describing “a curable resin composed of two or more species”, it may be described as “component (a) curable resin”.

1)
(A) A curable resin composed of one or more selected from epoxy resin, (meth) acrylated epoxy resin, and partial (meth) acrylated epoxy resin having active hydrogen in the molecule (however, active (B) A liquid crystal sealant containing a thermosetting agent as hydrogen (excluding hydrogen contained in a hydroxy group).
2)
The liquid crystal sealant according to 1) above, wherein the component (a) is a (meth) acrylated epoxy resin having active hydrogen in the molecule.
3)
The liquid crystal sealant according to 1) or 2) above, wherein the component (a) is a (meth) acrylated epoxy resin having a carboxy group, a sulfanyl group, or an amino group in the molecule.
4)
The liquid crystal sealing agent according to any one of 1) to 3), wherein the component (a) is a (meth) acrylated epoxy resin having a carboxy group in the molecule.
5)
5. The liquid crystal sealant according to any one of 1) to 4), wherein the component (a) is an acrylated resorcinol diglycidyl ether having a carboxy group in the molecule.
6)
Further, (c) a curable resin composed of one or more selected from epoxy resin, (meth) acrylated epoxy resin, and partial (meth) acrylated epoxy resin that does not have active hydrogen in the molecule. The liquid crystal sealing agent according to any one of 1) to 5) above, which contains (excluding hydrogen contained in a hydroxy group as active hydrogen).
7)
The liquid crystal sealant according to any one of 1) to 6) above, wherein the content of the component (a) is 5 to 50 parts by mass when the total amount of the liquid crystal sealant is 100 parts by mass.
8)
The liquid crystal sealant according to any one of 1) to 7) above, wherein the component (b) thermosetting agent is a polyhydric hydrazide compound.
9)
The liquid crystal sealing agent according to 8), wherein the component (b) thermosetting agent is one or more hydrazide compounds represented by the following formula (1).

[Wherein R ¹ to R ³ are each independently a hydrogen atom or the following formula (2)

(In the formula, n represents an integer of 1 to 6.)
The molecular skeleton represented by is shown. ]
10)
Furthermore, (d) Liquid crystal sealing agent as described in any one of said 1) thru | or 9) containing a silane coupling agent.
11)
Furthermore, (e) Liquid crystal sealing agent as described in any one of said 1) thru | or 10) containing an inorganic filler.
12)
Furthermore, (f) Liquid crystal sealing agent as described in any one of said 1) thru | or 11) containing a photoinitiator.
13)
A liquid crystal display cell sealed with a cured product obtained by curing the liquid crystal sealing agent according to any one of 1) to 12) above.

Since the liquid crystal sealant of the present invention has a high reaction rate at the time of thermosetting, the photothermal combined liquid crystal dropping method has sufficient curability even under wiring where light is difficult to reach. The degree of freedom can be secured and the manufacture of a highly reliable liquid crystal display panel can be facilitated, and furthermore, application to a liquid crystal dropping method in which the liquid crystal sealant is cured only by heat is also possible.

The liquid-crystal sealing compound of this invention is 1 type (s) or 2 or more types selected from the epoxy resin which has active hydrogen in a component (a) molecule | numerator, (meth) acrylated epoxy resin, and partial (meth) acrylated epoxy resin The curable resin which consists of is contained. However, in interpreting the active hydrogen, hydrogen contained in the hydroxy group is excluded. A hydroxy group generally has a large acid dissociation constant (pKa) and also has a weak nucleophilicity of the hydroxy group itself, so that it is difficult to function as a catalyst. Actually, a normal epoxy acrylate has a secondary hydroxy group, but does not function as a reaction catalyst during heat curing. In the present invention, good thermal reactivity can be realized by having the curable resin. Furthermore, since the curable resin has a functional group that reacts with light or heat such as a (meth) acryloyl group or an epoxy group, the amount of the curable resin taken into the cured product and dissolved in the liquid crystal can be dramatically reduced. The display characteristics of the liquid crystal display element are not impaired.
In the present specification, “(meth) acryl” means one or both of “acryl” and “methacryl”. In the present specification, “(meth) acryloyl” means one or both of “acryloyl” and “methacryloyl”.

Examples of the active hydrogen include active hydrogen contained in a carboxy group, a sulfanyl group, an amino group, a sulfo group, a phospho group, and the like. That is, as the component (a), for example, a (meth) acrylated epoxy resin and a partial (meth) acrylated epoxy resin having a carboxy group, a sulfanyl group, an amino group, a sulfo group, a phospho group or the like in the molecule, and a molecule Examples thereof include a curable resin containing one or more selected from epoxy resins having a carboxy group, a thiol group, an amino group, a sulfo group, a phospho group, and the like. Among the functional groups containing active hydrogen, a carboxy group, a thiol group, and an amino group are preferable, and a carboxy group is particularly preferable because of its function as a catalyst and ease of synthesis. For example, as an epoxy resin having an amino group, amine-modified bisphenol A type epoxy acrylate EBECRYL 3703 (manufactured by Daicel Cytec Co., Ltd.) and the like are easily available as commercial products.

The component (a) curable resin is preferably a (meth) acrylated epoxy resin rather than an epoxy resin or a partially (meth) acrylated epoxy resin. Since the (meth) acrylated epoxy resin reacts quickly by light, it is possible to further suppress dissolution in the liquid crystal. This curable resin can be obtained, for example, by reacting an acid anhydride, a polyvalent carboxylic acid, or the like with a (meth) acrylated epoxy resin obtained by a known reaction between an epoxy resin and (meth) acrylic acid. .

Specifically, first, epoxy resin, (meth) acrylic acid having a predetermined equivalent ratio, catalyst (for example, benzyldimethylamine, triethylamine, benzyltrimethylammonium chloride, triphenylphosphine, triphenylstibine, etc.), and a polymerization inhibitor (For example, methoquinone, hydroquinone, methylhydroquinone, phenothiazine, dibutylhydroxytoluene, etc.) is added and, for example, an esterification reaction is performed at 80 ° C. to 110 ° C. to obtain a (meth) acrylated epoxy resin. The obtained (meth) acrylated epoxy resin is reacted with an acid anhydride by the method described in, for example, JP-A-49-2601, JP-A-3-143911, JP-A-5-32746, A (meth) acrylated epoxy resin having active hydrogen in the molecule can be obtained. Here, the epoxy resin used as a raw material is not particularly limited, but a bifunctional or higher functional epoxy resin is preferable, for example, resorcinol diglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type. Epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidylamine Type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, phenol novolac type epoxy resin having triphenolmethane skeleton, and other bifunctional phenols Glycidyl ethers, difunctional alcohols diglycidyl ethers of, and their halides, hydrogenated product and the like. Among these, resorcinol diglycidyl ether, bisphenol A type epoxy resin, and bisphenol F type epoxy resin are preferable, and resorcinol diglycidyl ether is particularly preferable.

The content of component (a) is preferably 5 to 50 parts by mass, preferably 5 to 30 parts by mass, when the total amount of the liquid crystal sealant of the present invention is 100 parts by mass. Particularly preferred. If the amount of the component (a) is too small, sufficient thermosetting property cannot be obtained. On the other hand, if the amount is too large, the liquid crystal sealant has a high viscosity, which restricts the blending of other components.

The thermosetting agent that is the component (b) used in the liquid crystal sealing agent of the present invention is not particularly limited, and examples thereof include polyvalent amines, polyhydric phenols, hydrazide compounds, and the like. Compounds are particularly preferably used. For example, the aromatic hydrazide terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,2,4-benzenetrihydrazide, 1,4,5,8-naphthoic acid Examples include tetrahydrazide and pyromellitic acid tetrahydrazide. Examples of the aliphatic hydrazide compound include form hydrazide, acetohydrazide, propionic acid hydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, 1,4- Cyclohexane dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, iminodiacetic acid dihydrazide, N, N'-hexamethylenebissemicarbazide, citric acid trihydrazide, nitriloacetic acid trihydrazide, cyclohexanetricarboxylic acid trihydrazide, 1,3-bis (hydrazinocarbono Hydantoin skeleton such as ethyl) -5-isopropylhydantoin, preferably valine hydantoin skeleton (carbon atom of hydantoin ring is substituted with isopropyl group) Dihydrazide compounds having a rated), can be exemplified compounds represented by the above formula (1). Examples of the compound represented by the above (1) include tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris. (3-hydrazinocarbonylpropyl) isocyanurate, bis (2-hydrazinocarbonylethyl) isocyanurate, and the like can be mentioned, but the structure of the formula (1) is not limited thereto. Preferably, from the balance between curing reactivity and latency, isophthalic acid dihydrazide, malonic acid dihydrazide, adipic acid dihydrazide, tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate and tris (3-hydrazinocarbonylpropyl) isocyanurate, particularly preferably tris (2-hydrazinocarbonylethyl) isocyanurate.

The content of component (b) is preferably 1 part by mass to 20 parts by mass, more preferably 2 parts by mass to 15 parts by mass, when the total amount of the liquid crystal sealant of the present invention is 100 parts by mass. Yes, two or more may be used in combination.

The liquid crystal sealant of the present invention is selected from an epoxy resin, a (meth) acrylated epoxy resin, and a partially (meth) acrylated epoxy resin having no active hydrogen in the molecule as the component (c). Or you may contain the curable resin (However, the hydrogen contained in a hydroxyl group is remove | excluded as active hydrogen) which consists of 2 or more types. Examples thereof include an epoxy resin, a mixture of an epoxy resin and a (meth) acrylated epoxy resin, a (meth) acrylated epoxy resin, and a partial (meth) acrylated epoxy resin. The component (c) used in the present invention preferably has low contamination and solubility in liquid crystals. Examples of suitable epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy. Resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, hydantoin type epoxy Resin, isocyanurate type epoxy resin, phenol novolac type epoxy resin having triphenolmethane skeleton, other diglycidyl ethers of difunctional phenols, diglycidyl ether of difunctional alcohols Things, and their halides, but hydrogenated product or the like, but is not limited thereto. The (meth) acryloylated epoxy resin and the partial (meth) acryloylated epoxy resin can be obtained by a known reaction between an epoxy resin and (meth) acrylic acid. For example, epoxy resin, (meth) acrylic acid having a predetermined equivalent ratio, catalyst (for example, benzyldimethylamine, triethylamine, benzyltrimethylammonium chloride, triphenylphosphine, triphenylstibine, etc.), and a polymerization inhibitor (for example, methoquinone) For example, hydroquinone, methylhydroquinone, phenothiazine, dibutylhydroxytoluene, etc.) and an esterification reaction is carried out at 80 ° C. to 110 ° C., for example. Although it does not specifically limit as an epoxy resin used as a raw material, An epoxy resin more than bifunctional is preferable, for example, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a phenol novolac type epoxy resin , Cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin , Phenol novolac type epoxy resins having a triphenolmethane skeleton, other diglycidyl ethers of difunctional phenols, diglycidyl ethers of difunctional alcohols, and These halides, hydrogenated product and the like. Of these, bisphenol type epoxy resin and novolac type epoxy resin are more preferable from the viewpoint of liquid crystal contamination. Further, the ratio of the epoxy group to the (meth) acryloyl group is not limited, and is appropriately selected from the viewpoint of process compatibility and liquid crystal contamination.

When the liquid crystal sealant of the present invention contains the component (c), the amount used is appropriately determined in consideration of the workability and physical properties of the liquid crystal sealant obtained. Usually, when the total amount of the liquid crystal sealant is 100 parts by mass, it is preferably 20 parts by mass to 80 parts by mass, and more preferably 30 parts by mass to 70 parts by mass.

In the liquid crystal sealant of the present invention, the component (d) silane coupling agent can be used to improve adhesive strength and moisture resistance reliability. Examples of silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3-amino Propyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3 -Black Propyl methyl dimethoxy silane, 3-chloropropyl trimethoxy silane, and the like. The content of the silane coupling agent (d) in the liquid crystal sealant is preferably 0.05 parts by mass to 3 parts by mass when the total amount of the liquid crystal sealant of the present invention is 100 parts by mass.

In the liquid crystal sealant of the present invention, the component (e) inorganic filler can be used to improve the adhesive strength and improve the moisture resistance reliability. As this (e) inorganic filler, fused silica, crystalline silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, Aluminum hydroxide, magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably fused silica, crystalline silica, nitriding Silicon, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, aluminum silicate, more preferably fused silica, crystalline silica, aluminum Mina, is a talc. Two or more of these inorganic fillers may be mixed and used. If the average particle size is too large, it becomes a cause of defects such as failure to form a gap when laminating the upper and lower glass substrates when manufacturing a narrow gap liquid crystal cell, and therefore 3 μm or less is appropriate, and preferably 2 μm or less. The particle size can be measured with a laser diffraction / scattering particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd .; LMS-30).

The content of the inorganic filler (e) that can be used in the liquid crystal sealant of the present invention in the liquid crystal sealant is usually 3 parts by mass to 60 parts by mass when the total amount of the liquid crystal sealant of the present invention is 100 parts by mass. Yes, preferably 5 to 50 parts by mass. When there is too little content of an inorganic filler, since the adhesive strength with respect to a glass substrate falls and moisture resistance reliability is also inferior, the fall of the adhesive strength after moisture absorption may also become large. On the other hand, if the content of the inorganic filler is too large, the liquid crystal cell may not be able to form a gap because it is difficult to be crushed.

The liquid crystal sealant of the present invention may contain a component (f) a photoradical polymerization initiator in order to obtain a photothermal combination curable liquid crystal sealant. The radical photopolymerization initiator is not particularly limited as long as it is a compound that generates radicals by UV or visible light irradiation and initiates a chain polymerization reaction. For example, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, diethyl thioxanthone, Benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphine An oxide etc. can be mentioned. From the viewpoint of liquid crystal contamination, it is preferable to use those having a (meth) acryloyl group in the molecule. For example, 2-methacryloyloxyethyl isocyanate and 1- [4- (2-hydroxyethoxy) -phenyl]- The reaction product with 2-hydroxy-2methyl-1-propan-1-one is preferably used. This compound can be obtained by the method described in International Publication No. 2006/027982.

The content of the component (f) photopolymerization initiator that can be used in the liquid crystal sealant of the present invention in the liquid crystal sealant is usually 0.5 parts by mass when the total amount of the liquid crystal sealant of the present invention is 100 parts by mass. -20 parts by mass, preferably 1-15 parts by mass.

In the liquid crystal sealant of the present invention, a monomer or oligomer of (meth) acrylic acid ester may be used as necessary. Such monomers and oligomers include, for example, a reaction product of dipentaerythritol and (meth) acrylic acid, a reaction product of dipentaerythritol / caprolactone and (meth) acrylic acid, etc., but has a contamination property to liquid crystals. If it is low, it will not be restricted in particular.

In the liquid crystal sealing agent of the present invention, if necessary, additives such as curing accelerators such as organic acids and imidazoles, organic fillers, pigments, leveling agents, antifoaming agents, and solvents can be blended.

An example of a method for obtaining the liquid crystal sealant of the present invention is the following method. First, the component (c) and the component (f) are heated and dissolved in the component (a) as necessary. Next, after cooling to room temperature, component (b) is added, and if necessary, component (d), component (e), and organic filler, antifoaming agent, leveling agent, solvent, etc. are added, For example, the liquid crystal sealant of the present invention can be produced by uniformly mixing with a three-roll, sand mill, ball mill or the like and filtering with a metal mesh.

The liquid crystal display cell of the present invention is a cell in which a pair of substrates having predetermined electrodes formed on a substrate are arranged opposite to each other at a predetermined interval, the periphery is sealed with the liquid crystal sealant of the present invention, and the liquid crystal is sealed in the gap. is there. The kind of liquid crystal to be sealed is not particularly limited. Here, the substrate is composed of a combination of substrates made of at least one of glass, quartz, plastic, silicon, etc. and having light transmission properties. As a manufacturing method thereof, after adding a spacer (gap control material) such as glass fiber to the liquid crystal sealant of the present invention, the liquid crystal sealant is applied to one of the pair of substrates using a dispenser or a screen printing device. After that, temporary curing is performed at 80 ° C. to 120 ° C. as necessary. Thereafter, a liquid crystal is dropped inside the weir of the liquid crystal sealant, and the other glass substrate is overlaid in a vacuum to create a gap. After forming the gap, the liquid crystal display cell of the present invention can be obtained by curing at 90 ° C. to 130 ° C. for 1 to 2 hours. When used as a photothermal combination type, the liquid crystal sealant is irradiated with ultraviolet rays by an ultraviolet irradiator and photocured. Ultraviolet irradiation amount is preferably ^{500mJ / cm 2 ~ 6000mJ / cm} 2, more preferably ^{1000mJ / cm 2 ~ 4000mJ / cm} 2. Thereafter, if necessary, the liquid crystal display cell of the present invention can be obtained by curing at 90 ° C. to 130 ° C. for 1 to 2 hours. The liquid crystal display cell of the present invention thus obtained is free from display defects due to liquid crystal contamination and has excellent adhesion and moisture resistance reliability. Examples of the spacer include glass fiber, silica beads, and polymer beads. The diameter varies depending on the purpose, but is usually 2 μm to 8 μm, preferably 4 μm to 7 μm. The amount used is usually 0.1 to 4 parts by weight, preferably 0.5 to 2 parts by weight, more preferably 0.9 to 1 part by weight with respect to 100 parts by weight of the liquid crystal sealant of the present invention. About 5 parts by mass.

The liquid crystal sealant of the present invention has a very good thermosetting property and quickly cures in the heating step in the liquid crystal dropping method. Accordingly, the elution of the constituent components into the liquid crystal is extremely small, and display defects of the liquid crystal display cell can be reduced. Moreover, since it is excellent also in storage stability, it is suitable for manufacture of a liquid crystal display cell. Furthermore, since the cured product is excellent in various cured product characteristics such as adhesive strength, heat resistance, and moisture resistance, it is possible to produce a liquid crystal display cell with excellent reliability by using the liquid crystal sealant of the present invention. is there. In addition, the liquid crystal display cell prepared using the liquid crystal sealant of the present invention satisfies the characteristics required for a liquid crystal display cell having a high voltage holding ratio and a low ion density.

Hereinafter, the present invention will be described in more detail with reference to synthesis examples and examples, but the present invention is not limited to the examples. Unless otherwise specified, “part” and “%” in the text are based on mass.

[Synthesis Example 1: Synthesis of epoxy acrylate of bisphenol A type epoxy resin]
282.5 g of bisphenol A type epoxy resin (product name: YD-8125, manufactured by Nippon Steel Chemical Co., Ltd.) was dissolved in 266.8 g of toluene, and 0.8 g of dibutylhydroxytoluene was added to this as a polymerization inhibitor, and the temperature was raised to 60 ° C. Warm up. Thereafter, 117.5 g of acrylic acid having 100% equivalent of epoxy group was added, and the temperature was further raised to 80 ° C., and 0.6 g of trimethylammonium chloride as a reaction catalyst was added thereto, followed by stirring at 98 ° C. for about 30 hours. A reaction solution was obtained. This reaction solution was washed with water and toluene was distilled off to obtain 395 g of the desired bisphenol A type epoxy acrylate (acrylated bisphenol A type epoxy resin) (KAYARAD ^RTM R-93100).

[Synthesis Example 2: Synthesis of acid anhydride adduct of bisphenol A type epoxy acrylate]
4.84 g of the bisphenol A type epoxy acrylate obtained in Synthesis Example 1, 0.049 g of 4-dimethylaminopyridine, 6.07 g of triethylamine, and 1000 ml of methylene chloride were added and dissolved by stirring at room temperature. The acid 18.3g was added and it stirred at room temperature for 3 hours. The obtained reaction solution was washed 6 times with water, and then methylene chloride was distilled off to obtain 7 g of bisphenol A type epoxy acrylate having a carboxy group in the molecule. LC MS (m / z) = 787 (MH), IR 1709 cm- ¹ (COOH).

[Synthesis Example 3: Synthesis of Acrylated Resorcin Diglycidyl Ether]
Resorcin diglycidyl ether 181.2 g (Nagase ChemteX Corporation) was dissolved in 266.8 g of toluene, and 0.8 g of dibutylhydroxytoluene as a polymerization inhibitor was added thereto, and the temperature was raised to 60 ° C. Thereafter, 117.5 g of acrylic acid having 100% equivalent of epoxy group was added, and the temperature was further raised to 80 ° C., and 0.6 g of trimethylammonium chloride as a reaction catalyst was added thereto, followed by stirring at 98 ° C. for about 30 hours. A reaction solution was obtained. This reaction solution was washed with water, and toluene was distilled off to obtain 253 g of a desired resorcin diglycidyl ether epoxy acrylate (acrylated resorcin diglycidyl ether).

[Synthesis Example 4: Synthesis of acid anhydride adduct of acrylated resorcin diglycidyl ether]
3.66 g of epoxy acrylate of resorcin diglycidyl ether obtained in Synthesis Example 3, 0.049 g of 4-dimethylaminopyridine, 6.07 g of triethylamine and 1000 ml of methylene chloride were added and dissolved by stirring at room temperature. 11.8 g of maleic acid was added and stirred at room temperature for 2 hours. The obtained reaction solution was washed with water six times, and then methylene chloride was distilled off to obtain 5 g of acrylated resorcinol diglycidyl ether having a carboxy group in the molecule. LC MS (m / z) = 561 (MH), IR 1705 cm- ¹ (COOH).

[Examples 1 to 3, Comparative Examples 1 to 4]
Each curable resin component (components (a) and (c)) was mixed and stirred at the ratio shown in Table 1 below, and then heated and dissolved at 90 ° C. The photo radical polymerization initiator (component (f)) was heated and dissolved therein, and then cooled to room temperature. A silane coupling agent (component (d)), an inorganic filler (component (e)), a thermosetting agent ( Component (b)) was added and stirred, and then dispersed with a three-roll mill and filtered through a metal mesh (635 mesh) to prepare sealants for liquid crystal dropping methods of Examples 1 to 3.
Similarly, the curable resin component (component (c)) was heated at 90 ° C. at the ratio shown in Table 1 below. The photo radical polymerization initiator (component (f)) was heated and dissolved therein, and then cooled to room temperature. A silane coupling agent (component (d)), an inorganic filler (component (e)), a thermosetting agent ( Component (b)) and a curing accelerator were added, stirred, dispersed with a three-roll mill, and filtered through a metal mesh (635 mesh) to prepare sealing agents for liquid crystal dropping methods of Comparative Examples 1 to 4. .

The evaluation test was carried out by the following method.

(Adhesive strength measurement)
As a spacer, 1 g of 5 μm glass fiber was added to 100 g of the obtained liquid crystal sealant and mixed and stirred. This liquid crystal sealing agent was applied onto a 50 mm × 50 mm glass substrate, a 1.5 mm × 1.5 mm glass piece was bonded onto the liquid crystal sealing agent, and after irradiation with 3000 mJ / cm ² of ultraviolet rays by a UV irradiator, It was put into an oven and thermally cured at 120 ° C. for 1 hour. The shear adhesive strength of the glass pieces was measured with a bond tester (SS-30WD: manufactured by Seishin Shoji Co., Ltd.). The results are shown in Table 1.

(Moisture resistance measurement)
The same measurement sample as the above-mentioned adhesive strength test was prepared. The measurement sample was placed in a pressure cooker tester (TPC-411: manufactured by Tabai Espec Co., Ltd.) for 12 hours under the conditions of 121 ° C., 2 atm, and humidity of 100%, and then the shear bond strength of the glass pieces was measured with the above bond tester. Was measured. The results are shown in Table 1.

(Measurement of moisture absorption rate)
The obtained liquid crystal sealant was sandwiched between polyethylene terephthalate (PET) films and a thin film with a thickness of 100 μm was irradiated with 3000 mJ / cm ² of ultraviolet rays by a UV irradiator, and then put into an oven and thermally cured at 120 ° C. for 1 hour. After curing, the PET film was peeled off to obtain a sample. After measuring the weight of the sample, the sample was left in an environment of 60 ° C. and 90% RH for 12 hours and weighed again. Table 1 shows the weight change rate (%) with respect to the initial weight.

(Pot life measurement)
The viscosity change at 25 ° C. of the obtained liquid crystal sealant was measured. Viscosity was measured after being left for 72 hours at 25 ° C. and 50 RH%, and the rate of increase in viscosity (%) relative to the initial viscosity was determined. The results are shown in Table 1.

(Creation of liquid crystal cell for evaluation)
An alignment film solution (PIA-5540-05A; manufactured by Chisso Corporation) was applied to a substrate with a transparent electrode, baked, and rubbed. A liquid crystal sealant is dispensed on this substrate so that the line width after bonding becomes 1 mm to form a main seal and a dummy seal, and then a fine droplet of liquid crystal (JC-5015LA; manufactured by Chisso Corporation) is put into a frame of a seal pattern. It was dripped in. Furthermore, an in-plane spacer (NATOCO SPACER KSEB-525F; manufactured by NATCO; gap width of 5 μm after bonding) is sprayed and thermally fixed on another rubbing-treated substrate, and the substrate is first vacuumed using a bonding apparatus. The liquid crystal dripped substrate was attached. After opening the atmosphere to form a gap, masking only the seal pattern frame, irradiating with 50 mJ / cm ² of UV light with a UV irradiator, putting it in an oven and thermosetting at 120 ° C. for 1 hour, liquid crystal test cell for evaluation It was created.

The insertion resistance of the seal of the prepared liquid crystal cell for evaluation and the liquid crystal alignment disorder in the vicinity of the seal were observed with a polarizing microscope, and the evaluation of the insertion resistance and the liquid crystal alignment in the vicinity of the seal was performed according to the following criteria. The results are shown in Table 1.

(Evaluation of insertion resistance)
A: The insertion of the liquid crystal into the seal is less than 0.2 mm, and there is no problem in sealing the liquid crystal.
○: The insertion of the liquid crystal into the seal is 0.2 mm or more and less than 0.4 mm, and there is no problem in sealing the liquid crystal.
(Triangle | delta): The insertion of the liquid crystal to a seal | sticker is 0.4 mm or more and less than 0.6 mm, and is a level which does not have a problem in sealing of a liquid crystal.
X: The insertion of the liquid crystal into the seal is 0.6 mm or more and less than 1.0 mm, and there is no problem in sealing the liquid crystal.
XX: The seal is broken and a cell cannot be formed.

(Evaluation of liquid crystal alignment near the seal)
A: The alignment disorder of the liquid crystal is less than 0.2 mm from the seal.
○: The alignment disorder of the liquid crystal is 0.2 mm or more and less than 0.4 mm from the seal.
Δ: The alignment disorder of the liquid crystal is 0.4 mm or more and less than 0.6 mm from the seal.
X: The alignment disorder of the liquid crystal is 0.6 mm or more and less than 1.0 mm from the seal.
XX: The seal is broken and a cell cannot be formed.

(Curing rate measurement)
With respect to the obtained liquid crystal sealant, the complex viscosity was measured with a dynamic viscoelasticity measuring device (Rhesol-G5000, manufactured by UBM Co., Ltd.). The setting of the dynamic viscoelasticity measuring apparatus is as follows. Cone: Parallel cone with a diameter of 20 mm, frequency: 1 Hz, distortion angle: 3 deg. The measurement temperature was raised from 30 ° C. to 120 ° C. at a rate of 18 ° C./min, and then maintained at 120 ° C. Table 1 shows the time when the viscosity reached 10,000 Pa · s.

From the results of Table 1, Comparative Example 1 that does not contain a curing accelerator component is inferior in curability, and as a result, alignment failure occurs in the panel display characteristics. In addition, those using CIC acid, dodecanedioic acid, or a thermal radical initiator as a curing accelerator have improved the curability, but have problems with liquid crystal contamination and moisture-resistant adhesion. On the other hand, in Examples 1 to 3, it is confirmed that other characteristics are at a usable level while improving the curability. In particular, Examples 1 and 2 show very excellent results in all characteristics.
From these results, it can be said that the liquid crystal sealing agent of the present invention is excellent in workability because of its excellent storage stability and curability, and it is excellent in liquid crystal contamination, moisture-resistant adhesion, and panel display characteristics because of its high liquid crystal display cell performance. It can be said that reliability can be realized.

Since the liquid crystal sealant of the present invention is excellent in workability, it enables stable production of liquid crystal display cells and contributes to ensuring long-term reliability of the liquid crystal display cells.

Claims

(A) A curable resin composed of one or more selected from epoxy resin, (meth) acrylated epoxy resin, and partial (meth) acrylated epoxy resin having active hydrogen in the molecule (however, active (B) A liquid crystal sealant containing a thermosetting agent as hydrogen (excluding hydrogen contained in a hydroxy group).
The liquid crystal sealant according to claim 1, wherein the component (a) is a (meth) acrylated epoxy resin having active hydrogen in the molecule.
The liquid crystal sealant according to claim 1 or 2, wherein the component (a) is a (meth) acrylated epoxy resin having a carboxy group, a sulfanyl group, or an amino group in the molecule.
The liquid crystal sealant according to any one of claims 1 to 3, wherein the component (a) is a (meth) acrylated epoxy resin having a carboxy group in the molecule.
The liquid crystal sealant according to any one of claims 1 to 4, wherein the component (a) is an acrylated resorcinol diglycidyl ether having a carboxy group in the molecule.
Further, (c) a curable resin composed of one or more selected from epoxy resin, (meth) acrylated epoxy resin, and partial (meth) acrylated epoxy resin that does not have active hydrogen in the molecule. The liquid crystal sealing agent according to any one of claims 1 to 5, which contains (however, hydrogen contained in a hydroxy group is excluded as active hydrogen).
The liquid crystal sealant according to any one of claims 1 to 6, wherein the content of the component (a) is 5 parts by mass to 50 parts by mass when the total amount of the liquid crystal sealant is 100 parts by mass.
The liquid crystal sealant according to any one of claims 1 to 7, wherein the component (b) thermosetting agent is a polyhydric hydrazide compound.
The liquid crystal sealant according to claim 8, wherein the component (b) thermosetting agent is one or more hydrazide compounds represented by the following formula (1).

[Wherein R 1 to R 3 are each independently a hydrogen atom or the following formula (2)

(In the formula, n represents an integer of 1 to 6.)
The molecular skeleton represented by is shown. ]
Furthermore, (d) The liquid-crystal sealing compound as described in any one of Claim 1 thru | or 9 containing a silane coupling agent.
Furthermore, (e) The liquid-crystal sealing compound as described in any one of Claims 1 thru | or 10 containing an inorganic filler.
Furthermore, the liquid-crystal sealing compound as described in any one of Claims 1 thru | or 11 containing (f) radical photopolymerization initiator.
A liquid crystal display cell sealed with a cured product obtained by curing the liquid crystal sealing agent according to any one of claims 1 to 12.