JPWO2008016122A1 - Liquid crystal sealant, liquid crystal display panel manufacturing method using the same, and liquid crystal display panel - Google Patents

Abstract

The present invention relates to a liquid crystal sealant that can be applied to a liquid crystal display panel. The liquid crystal sealant of the present invention includes (1) an epoxy resin and an amine-based thermal latent curing agent, (2) a melting point of 150 ° C. or less, a dihydrazide-based, imidazole-modified, amine-adduct-based, and One or more thermal latent curing agents selected from the group consisting of polyaminourea-based thermal latent curing agents, and (3) a melting point of 180 ° C. or higher, dihydrazide-based, imidazole-modified, and diamide-based thermal latent curing And one or more thermal latent curing agents selected from the group consisting of agents. Such a liquid crystal sealant has a high curing rate and high moisture resistance. Moreover, since the reactivity in the low temperature area | region including room temperature is low, since the high viscosity stability is maintained, the pot life is long. Therefore, if a liquid crystal display panel is manufactured using such a liquid crystal sealant, a high-quality liquid crystal display panel can be manufactured while maintaining high productivity.

Description

  The present invention relates to a liquid crystal sealant, a method for producing a liquid crystal display panel using the same, and a liquid crystal display panel.

  In recent years, liquid crystal display panels have been widely used as display panels for various electronic devices such as mobile phones because of their advantages such as thinness, light weight, and low power consumption. A liquid crystal display panel has a structure in which liquid crystal is sealed between two substrates bonded together with a liquid crystal sealant. The liquid crystal display panel controls the orientation of the liquid crystal by applying a voltage to the liquid crystal and modulates the transmitted light. A device that displays an image by adjusting.

  The liquid crystal display panel is mainly manufactured by a liquid crystal injection method or a liquid crystal dropping method. In the liquid crystal injection method, first, a liquid crystal sealant is applied to either one of two substrates by a dispenser or screen printing, and then the liquid crystal sealant is dried by a pre-cure process (preliminary drying). At this time, a part to be a liquid crystal injection port is provided in a part of the frame. Next, after superimposing the two substrates so as to face each other, the substrates are bonded to each other by heating and pressing. In a vacuum, after injecting liquid crystal into the empty cell from the liquid crystal injection port, the liquid crystal injection port is sealed with a liquid crystal sealant or the like to manufacture a liquid crystal display panel in which liquid crystal is sealed between the substrates. Is done.

  One liquid crystal dropping method includes the following steps. First, a liquid crystal sealant is applied to one of the two substrates constituting the liquid crystal display panel to form a frame-shaped display region filled with liquid crystal. Here, the method for applying the liquid crystal sealant is not particularly limited, and generally, the same method as the liquid crystal injection method is used. Next, an appropriate amount of liquid crystal is dropped in the formed frame or on the other substrate, and the two substrates are superposed in a high vacuum with the liquid crystal sealant being uncured. Then, the two stacked substrates are bonded to each other, for example, by returning them to atmospheric pressure, and then the liquid crystal sealant is cured to produce a liquid crystal display panel in which liquid crystal is sealed between the substrates. . In such a liquid crystal dropping method, post-curing by heating is generally performed after the liquid crystal sealant is temporarily cured by irradiating the stacked substrates with ultraviolet rays or the like.

  In the above-described liquid crystal injection method, it takes a long time to inject liquid crystal into the cell, and a heat treatment for several hours in a temperature range of 120 to 150 ° C. is required to cure the liquid crystal sealant. For this reason, low productivity is regarded as a problem. In that respect, according to the liquid crystal dropping method, since the liquid crystal can be sealed in a shorter time than the liquid crystal injection method, productivity is improved. Therefore, recently, the liquid crystal dropping method is becoming mainstream as a method for manufacturing a liquid crystal display panel.

  By the way, as a liquid crystal sealing agent used for a liquid crystal display panel, a thermosetting liquid crystal sealing agent (hereinafter simply referred to as a thermosetting sealing agent) mainly composed of an epoxy resin has been proposed (for example, Patent Documents). 1). However, such a thermosetting sealant, when used in the production of a liquid crystal display panel, tends to shift the arrangement of the seal due to the fact that the viscosity is lowered by heat, and the slow curing speed is a problem. Is done.

  When a liquid crystal sealant having a slow curing rate is used in the liquid crystal dropping method, components such as monomers may gradually dissolve or ooze out from the uncured liquid crystal sealant. In such a liquid crystal display panel in which components such as monomers are dissolved in the liquid crystal, it is difficult to control the alignment of the liquid crystal even when a voltage is applied, so that the display property of the liquid crystal is low, and color unevenness is also caused. It becomes a problem. Therefore, from the viewpoint of improving the productivity and quality of the liquid crystal display panel, it is desired to propose a liquid crystal sealant having a high curing rate.

Therefore, as a liquid crystal sealant having a high curing rate, a liquid crystal sealant that uses a photocurable component that is cured by ultraviolet irradiation and a thermosetting component that is cured by heating has been proposed (for example, Patent Documents 2 and 3). reference). In addition, the liquid crystal sealing agents proposed in Patent Documents 1 to 3 include 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (melting point 120 ° C.) having a melting point of 120 ° C. as a thermal latent curing agent. ) Is used. Such a heat-latent curing agent is rapidly melted at 120 to 150 ° C., which is a general curing temperature, and is highly reactive, so that an improvement in the curing rate is expected.
JP 2004-123909 A JP 2001-133794 A JP 2002-214626 A

  However, since the low-melting-point heat latent curing agent has a relatively high water solubility, the liquid crystal sealant using such a heat-latent curing agent has a problem of moisture resistance. When the liquid crystal sealant in which the moisture resistance is concerned is used for the liquid crystal display panel as described above, the adhesive strength of the liquid crystal sealant after curing is lowered, and the display property of the liquid crystal display panel may be deteriorated.

  Also, in the field of manufacturing liquid crystal display panels, the length of usable time of the liquid crystal sealant is regarded as important. The pot life refers to the time during which the liquid crystal sealant can be preferably used. The phrase “a liquid crystal sealant can be preferably used” means that the liquid crystal sealant can be easily applied to a substrate, can be applied, and the like. The pot life of the liquid crystal sealant becomes shorter as the viscosity of the liquid crystal sealant increases. The reason is that when the viscosity of the liquid crystal sealant increases, it becomes difficult to apply the liquid crystal sealant on the substrate, and it is necessary to replace the liquid crystal sealant used in an apparatus such as a dispenser. Therefore, in order to increase the pot life of the liquid crystal sealant, it is preferable that the viscosity remains stable for a long time without changing, that is, the viscosity stability is increased.

  However, the liquid crystal sealant containing the highly reactive thermal latent curing agent as described above easily increases in viscosity because the curing reaction proceeds easily even in a low temperature region such as around room temperature. Therefore, the viscosity stability of the liquid crystal sealant is lowered, and the pot life may be shortened.

  Therefore, in view of the above problems, the present invention provides a liquid crystal sealant that has a high curing rate and good moisture resistance, and further maintains a high viscosity stability for a long time. The purpose. In addition, by using a liquid crystal sealant with such excellent characteristics and a long service life, it is possible to produce a liquid crystal display panel that can produce a liquid crystal display panel with high moisture resistance and reliability while maintaining high productivity. A second object is to provide a method.

  As a result of intensive studies, the present inventors have solved the above problem by using a thermal latent curing agent having a melting point of 150 ° C. or lower and a thermal latent curing agent having a melting point of 180 ° C. or higher in combination. As a result, the present invention has been completed.

ただし、一般式（Ａ）中のＲは、炭素数８以上のアルキレン基を表す。
［５］前記液晶シール剤は、前記（１）〜（３）成分が均一に混合された一液タイプである［１］〜［４］いずれかに記載の液晶シール剤。
［６］ 前記（２）成分および（３）成分の総配合量が、前記液晶シール剤１００質量部中に１〜２５質量部である［１］〜［５］いずれかに記載の液晶シール剤。
［７］ 前記（２）成分の配合質量をＷ１とし、前記（３）成分の配合質量をＷ２とするとき、０．２≦Ｗ２／（Ｗ１＋Ｗ２）≦０．８である［１］〜［６］いずれかに記載の液晶シール剤。
［８］ 前記（２）成分および（３）成分の活性水素当量の合計が、前記（１）成分のエポキシ当量に対して０．３〜３．０である［１］〜［７］いずれかに記載の液晶シール剤。That is, the said subject is solved by the liquid-crystal sealing compound of this invention.
[1] (1) an epoxy resin, (2) a first thermal latent curing agent having a melting point of 150 ° C. or lower, and (3) a second thermal latent curing agent having a melting point of 180 ° C. or higher, The component (2) is one or more thermal latent curing agents selected from the group consisting of dihydrazide, imidazole, amine adduct, polyamine, and polyaminourea thermal latent curing agents, The liquid crystal sealing agent in which the component (3) is one or more thermal latent curing agents selected from the group consisting of dihydrazide-based, imidazole-based, and diamide-based thermal latent curing agents.
[2] The liquid crystal sealant according to [1], wherein the components (2) and (3) are dihydrazide-based thermal latent curing agents.
[3] The liquid crystal sealant according to [1] or [2], wherein the solubility of the component (3) in 100 ml of water at 25 ° C. is 20 g or less.
[4] The liquid crystal sealant according to any one of [1] to [3], wherein the component (3) is a compound represented by the following general formula (A).

However, R in the general formula (A) represents an alkylene group having 8 or more carbon atoms.
[5] The liquid crystal sealant according to any one of [1] to [4], wherein the liquid crystal sealant is a one-component type in which the components (1) to (3) are uniformly mixed.
[6] The liquid crystal sealant according to any one of [1] to [5], wherein the total amount of the component (2) and the component (3) is 1 to 25 parts by mass in 100 parts by mass of the liquid crystal sealant. .
[7] When the blending mass of the component (2) is W1 and the blending mass of the component (3) is W2, 0.2 ≦ W2 / (W1 + W2) ≦ 0.8 [1] to [6 ] Liquid crystal sealing agent in any one.
[8] Any of [1] to [7], wherein the total of active hydrogen equivalents of the component (2) and the component (3) is 0.3 to 3.0 with respect to the epoxy equivalent of the component (1). Liquid crystal sealing agent as described in 2.

Moreover, the said subject is solved by the manufacturing method of the liquid crystal display panel of this invention, and the liquid crystal display panel obtained by this.
[9] In a method for manufacturing a liquid crystal display panel manufactured by bonding two opposing substrates through a liquid crystal sealant, pixel alignment is performed using the liquid crystal sealant described in [1] to [8] above. A step of preparing a substrate having a frame-like display region formed so as to surround the region and provided with a liquid crystal inlet, and after heating the two substrates through the liquid crystal sealant, heating The step of forming the liquid crystal cell between the substrates by pressing and bonding the substrates together, the step of injecting the liquid crystal into the liquid crystal cell from the injection port, and the liquid crystal by the sealing agent for sealing And a step of sealing an injection port of the injected liquid crystal cell.
[10] In a method for manufacturing a liquid crystal display panel manufactured by bonding two opposing substrates through a liquid crystal sealant, pixel alignment is performed by the liquid crystal sealant described in [1] to [8] above. A step of preparing a substrate having a frame-shaped display region formed so as to surround the region, a step of dropping liquid crystal in the uncured display region or on the other substrate, and the liquid crystal A step of superimposing the substrate onto which the liquid crystal is dropped and the other substrate under reduced pressure, and a step of curing the liquid crystal sealant between the two superposed substrates by heating. Panel manufacturing method.
[11] A liquid crystal display panel obtained by the method for manufacturing a liquid crystal display panel according to [9] or [10].

  According to the present invention, it is possible to provide a liquid crystal sealant that has a high curing rate and good moisture resistance, and further maintains a high viscosity stability for a long time. In addition, by using a liquid crystal sealant with such excellent characteristics and a long service life, it is possible to produce a liquid crystal display panel that can produce a liquid crystal display panel with high moisture resistance and reliability while maintaining high productivity. A method can be provided.

  Next, the present invention will be described in detail. In the following description, a numerical range is defined using “to”, but “to” in the present invention includes a boundary value. For example, “10 to 100” means 10 or more and 100 or less.

  The liquid crystal sealant of the present invention includes (1) an epoxy resin, (2) a thermal latent curing agent having a melting point of 150 ° C. or lower, and (3) a thermal latent curing agent having a melting point of 180 ° C. or higher.

(1) Epoxy resin The epoxy resin of the present invention refers to a compound having one or more epoxy groups in the molecule. Examples of preferable epoxy resins used in the liquid crystal sealant of the present invention include aromatic diols represented by bisphenol A, bisphenol S, bisphenol F, bisphenol AD, and the like, and those modified with ethylene glycol, propylene glycol, and alkylene glycol. Aromatic glycidyl ether compounds obtained by the reaction of diols with epichlorohydrin; novolak resins derived from phenol or cresol and formaldehyde, polyphenols typified by polyalkenylphenols and copolymers thereof, and epichlorohydrin And a novolak type polyvalent glycidyl ether compound obtained by the reaction with glycidyl ether compound of xylylene phenol resin.

  Examples of preferable epoxy resins include cresol novolac type epoxy resins, phenol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, triphenolmethane type epoxy resins, triphenolethane type epoxy resins, and trisphenol types. Epoxy resins, dicyclopentadiene type epoxy resins, and biphenyl type epoxy resins are included. Examples of particularly preferred epoxy resins include these acrylic rubber-modified epoxy resins.

  These epoxy resins can be used alone or in combination of two or more kinds in the liquid crystal sealing agent of the present invention.

  In addition, the epoxy resin used in the present invention preferably has a softening point temperature measured by a ring and ball method of 40 ° C. or higher, and more preferably has a mass average molecular weight in the range of 1000 to 10,000. Such an epoxy resin has low solubility and diffusibility in liquid crystals. Therefore, the liquid crystal display panel manufactured by the liquid crystal sealing agent using such an epoxy resin has good display properties. The weight average molecular weight of the epoxy resin can be measured, for example, by gel permeation chromatography (GPC) using polystyrene as a standard. Further, as the epoxy resin, one that has been highly purified by molecular distillation or the like and from which impurities have been removed is preferably used.

  It is preferable that the compounding quantity of an epoxy resin is 5-50 mass parts with respect to 100 mass parts of liquid crystal sealing agents, More preferably, it is 10-30 mass parts. Such a liquid crystal sealant has good heat resistance. However, when the blending amount is less than 5 parts by mass, the mechanical strength of the cured product after the liquid crystal sealant is cured is lowered. On the other hand, when the blending amount exceeds 50 parts by mass, the heat resistance of the liquid crystal sealant may be lowered.

[Heat latent curing agent]
Thermal latent curing agent means that while maintaining the reaction rate at the curing temperature of a normal liquid crystal sealant, the reaction rate in the low temperature region near room temperature can be extremely low even when mixed with an epoxy resin, A curing agent that exhibits reaction activity with epoxy groups when exposed to light or light. Since the liquid crystal sealant containing such a heat latent curing agent has low reactivity at the time of application and storage, the viscosity stability becomes high.

  The liquid crystal sealant according to the present invention includes two types of thermal latent curing agents having different melting points, that is, (2) a first thermal latent curing agent having a melting point of 150 ° C. or lower, and (3) a melting point of 180 ° C. The second thermal latent curing agent as described above is used in combination. In general, it is known that when a thermal latent curing agent is included in a liquid crystal sealant, the viscosity stability of the liquid crystal sealant at the time of application and storage is increased. By the way, when the first heat latent curing agent having a low melting point and the second heat latent curing agent having a high melting point having low reactivity near room temperature are used together as in the present invention, the reactivity near room temperature is obtained. Is kept lower, so that the viscosity stability is extremely high.

  A thermal latent curing agent cures an epoxy resin by reacting with an epoxy group or promoting polymerization between epoxy groups. However, not all thermal latent curing agents react with epoxy groups, and a part of them remains dispersed in the cured product. Here, in the region containing the thermal latent curing agent remaining in the cured product, if the thermal latent curing agent constituting this region is a substance that easily absorbs water, the cured product itself easily absorbs water and moisture resistance decreases. There are things to do.

  On the other hand, the liquid crystal sealing agent of the present invention has a low melting point thermal latent curing agent when the liquid crystal sealing agent is heated at a curing temperature (around 120 to 150 ° C.) used in a normal liquid crystal dropping method. While being subjected to the reaction, the high-melting point thermal latent curing agent remains in the cured product and is dispersed in the base material. Such a high melting point thermal latent curing agent has a rigid molecular skeleton and high crystallinity. Therefore, in the cured product obtained by curing the liquid crystal sealant of the present invention, a highly hydrophobic region composed of a high-melting-point heat-latent curing agent is dispersed and remains. Moisture resistance is extremely high.

  The liquid crystal sealant of the present invention is useful as a one-pack type and has high storage stability. The one-pack type liquid crystal sealing agent refers to a liquid crystal sealing agent in which a main component such as an epoxy resin and a curing accelerating component such as a thermal latent curing agent are uniformly mixed in advance before use. High storage stability means that the curing reaction hardly proceeds even when the liquid crystal sealant is stored near room temperature. Specifically, it is preferable that the increase rate of the viscosity when the liquid crystal sealant is stored at 25 ° C. for 5 days is not more than twice the viscosity of the liquid crystal sealant before storage.

(2) Thermal latent curing agent having a melting point of 150 ° C. or lower The “thermal latent curing agent having a melting point of 150 ° C. or lower” used as the first thermal latent curing agent in the present invention is a melting point of 150 ° C. It is the following and refers to a compound having thermal latent curability.

  Preferred examples of such component (2) include dihydrazide-based, imidazole-based, amine adduct-based, polyamine-based, and polyaminourea-based thermal latent curing agents. You may use these individually or in combination of multiple types. Further, the melting point of the thermal latent curing agent can be measured by a known melting point measuring apparatus.

  The dihydrazide-based thermal latent curing agent refers to a compound having two hydrazide groups in one molecule and having thermal latent curability. A preferred example of such a heat latent curing agent includes organic acid dihydrazide.

  The organic acid dihydrazide means an organic acid having two hydrazide groups in one molecule. Examples of the organic acid dihydrazide preferably used as the component (2) of the present invention include 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (melting point: 120 ° C.), parin dihydrazide (melting point: 123 to 125 ° C.) Is included.

  Examples of commercially available organic acid dihydrazides having a melting point of 150 ° C. or lower include Amicure VDH (melting point 120 ° C., Ajinomoto Fine Techno Co., Ltd.) which is palin dihydrazide, Amicure which is 7,11-octadiene-1,18 dicarbohydrazide UDH (Ajinomoto Fine Techno Co., Ltd. melting point 150 ° C.) is included.

  The imidazole-based thermal latent curing agent is (i) an imidazole derivative in which a substituent or the like is introduced into imidazole, or (ii) imidazole obtained by reacting imidazole with a compound capable of forming a salt with the imidazole. Denatured product.

  Examples of the component (i) include 2-phenylimidazole, Curazole 2PZ (melting point: 137 to 147 ° C., manufactured by Shikoku Kasei Co., Ltd.), and 2-methylimidazole, Curazole 2MZ-P (manufactured by Shikoku Chemicals Co., Ltd.). 1-cyanoethyl-2-phenylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd., melting point 105 to 111 ° C.). These are easily available as commercial products.

  Examples of the compound as the component (ii) include a resin into which imidazole is introduced. Examples of such imidazole-modified products include C11Z-CNS (manufactured by Shikoku Chemicals Co., Ltd., melting point 143 to 149 ° C.), 2PZ-OK (manufactured by Shikoku Chemicals Co., Ltd., melting point 135 ° C.), Adeka Hardener EH4346S (melting point 125 ° C. ), Adeka Hardener EH4347S (melting point: 105 ° C.), Adeka Hardener EH4356S (melting point: 110 ° C.) (above, manufactured by ADEKA Corporation). These are easily available as commercial products.

  The amine adduct thermal latent curing agent refers to an addition compound obtained by reacting an amine compound having thermal latent curing property and catalytic activity with an arbitrary compound. Such an amine adduct thermal latent curing agent is activated by dissociation of the amine by heat. Examples of the amine compound include compounds having a 1,2, tertiary amino group.

  Examples of the amine adduct thermal latent curing agent preferably used as the component (2) of the present invention include Amicure PN-40 (melting point 110 ° 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.), Amicure MY-H (melting point 130 ° C.) (manufactured by Ajinomoto Fine Techno Co., Ltd.).

  The polyamine thermal latent curing agent has a polymer structure that is a reaction product of an amine and an epoxy, and has a thermal latent curability in which an amine having catalytic activity forms a stabilizing structure with an arbitrary compound. Refers to the compound shown. Examples of the polyamine thermal latent curing agent preferably used as the component (2) of the present invention include ADEKA HARDNER EH4357S (manufactured by ADEKA Corporation, melting point 73 to 83 ° C.).

  The polyaminourea-based thermal latent curing agent refers to a compound having a urea bond obtained by reacting an amine, urea and an isocyanate compound. Examples of polyaminourea type thermal latent curing agents preferably used as the component (2) of the present invention include Fujicure FXE-1000 (Fuji Kasei Kogyo Co., Ltd. melting point 120 ° C.) and Fujicure FXE-1030 (Fuji Kasei Kogyo ( Co., Ltd., melting point 140 ° C.), Omicure 94 (ICI Japan Co., Ltd. melting point 127-129 ° C.).

  The component (2) used in the present invention preferably has a melting point of 100 ° C. or higher. Such a heat latent curing agent has a very good thermosetting property, and thus improves the curing rate of the liquid crystal sealant. When the melting point temperature is less than 100 ° C., there is a concern that the reactivity in the low temperature region becomes higher than necessary and the viscosity stability becomes extremely high.

(3) Thermal latent curing agent having a melting point of 180 ° C. or higher In the present invention, the “thermal latent curing agent having a melting point of 180 ° C. or higher” used as the second thermal latent curing agent is a melting point of 180 ° C. It is the above and it says the compound which has thermal latent curability. Preferred examples of such a second heat latent curing agent include dihydrazide, imidazole, and diamide heat latent curing agents. Since the liquid crystal sealant using such a heat latent curing agent has very good viscosity stability at room temperature, it is possible to produce a liquid crystal display panel while maintaining a long working life. it can. The thermal latent curing agents may be used alone or in combination of two or more.

  Among these, as the component (3), a dihydrazide thermal latent curing agent is preferable. Examples of such dihydrazide-based thermal latent curing agents include isophthalic acid dihydrazide (manufactured by IDH Nippon Finechem Co., Ltd., melting point 220 ° C.), 1,3,5-tris (2-hydrazinocarbonylethyl) -isocyanurate. (HCIC Nippon Finechem Co., Ltd., melting point 197 ° C.).

  Among the dihydrazide thermal latent curing agents, as the component (3), an organic acid dihydrazide is preferable, and a compound represented by the following general formula (A) is preferable. The organic acid dihydrazide of the present invention refers to a compound having an alkylene group having 8 or more carbon atoms obtained by hydrazation of an aliphatic dicarboxylic acid.

  Here, examples of the aliphatic dicarboxylic acid include adipic acid dihydrazide (manufactured by ADH Nippon Finechem Co., Ltd., melting point 181 ° C., solubility 10 g in 100 ml of water at 25 ° C.). The liquid crystal sealant using the organic acid dihydrazide represented by the general formula (A) has good water resistance. For this reason, since the cured liquid crystal sealant has high water resistance, when applied to a liquid crystal display panel, the adhesive strength between the liquid crystal sealant cured at high humidity and the substrate is high, and excellent moisture resistance reliability. A liquid crystal display panel exhibiting properties can be obtained.

上記の一般式（Ａ）中のＲは、炭素数８以上のアルキレン基を表す。

R in the general formula (A) represents an alkylene group having 8 or more carbon atoms.

  Examples of the organic acid dihydrazide preferably used as the component (3) of the present invention include sebacic acid dihydrazide (manufactured by SDH Nippon Finechem Co., Ltd., melting point 190 ° C., insoluble in 100 ml of water at 25 ° C.), dodecanedioic acid dihydrazide (N-12 made by Nippon Finechem Co., Ltd., insoluble in 100 ml of water having a melting point of 189 ° C. and 25 ° C.).

  The imidazole-based thermal latent curing agent is similar to the definition explained in the component (2), (i) an imidazole derivative in which a substituent is introduced into imidazole, or (ii) imidazole, a resin or imidazole, An imidazole-modified product obtained by reacting with a compound capable of forming a salt. Among these, as the component (3), an imidazole compound having a melting point of 180 ° C. or higher by increasing the molecular weight or strengthening the bonding of the molecules constituting the resin skeleton is applicable.

  Among the imidazole-based heat latent curing agents as described above, the imidazole derivative as the component (i) is preferable as the component (3). Examples of such imidazole derivatives include 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1 ')]-ethyl-s-triazine. Such a compound is available as a commercial product such as Curesol 2E4MZ-A (manufactured by Shikoku Chemicals Co., Ltd., melting point 215 to 225 ° C.).

  The diamide type heat latent curing agent of the present invention refers to a compound having two amide groups in one molecule and having heat latent curability. Examples of the diamide type heat latent curing agent preferably used as the component (3) of the present invention include dicyandiamide (melting point 209 ° C. and the like). Specifically, AH-154 (melting point 200 ° C.), AH-162 (melting point 200 ° C.) (above, manufactured by Ajinomoto Fine Techno Co., Ltd.) are included, and these are readily available as commercial products.

  The compounds preferably used as the component (3) may be used alone or in combination of two or more. In addition to the above component (3), hydrazides such as p-hydroxybenzoic acid hydrazide (manufactured by Nippon Finechem Co., Ltd., melting point 264 ° C.) may be used. Furthermore, the thermal latent curing agent used as the component (3) is preferably highly purified by a water washing method, a recrystallization method, or the like.

  The component (3) preferably has a solubility of 20 g or less in 100 ml of water at 25 ° C. Particularly preferably, the solubility is 5 g or less. Since the liquid crystal sealant using the component (3) has good moisture resistance, as a result, the moisture resistance reliability of the liquid crystal display panel is improved. Here, as the solubility of the component (3) approaches 0 g, the moisture resistance of the prepared liquid crystal sealant improves. However, when the solubility exceeds 20 g, the moisture resistance of the liquid crystal sealant is low and inferior, and therefore, when applied to a liquid crystal display panel, the moisture resistance reliability may be lowered.

  In order to improve the moisture resistance and curing rate of the liquid crystal sealant, it is more preferable to use a dihydrazide-based thermal latent curing agent in combination as the component (2) and the component (3). To date, monohydrazide-based thermal latent curing agents for liquid crystal sealants are known. As described above, the monohydrazide thermal latent curing agent having one hydrazide group as a functional group has a lower melting point and higher compatibility with other resins than a polyfunctional type such as dihydrazide. The latent curability is good. However, on the other hand, a cured product of a liquid crystal sealant using such a heat-latent curing agent has a problem of low crosslinking density and low moisture resistance. However, since the dihydrazide-based thermal latent curing agent has two hydrazide groups as functional groups, it has good reactivity in addition to high latent curability. Therefore, when such a heat-latent curing agent is applied to a liquid crystal sealant, a cured product having a high crosslinking density and excellent mechanical strength and water resistance can be obtained.

  The total amount of the component (2) and the component (3) is preferably 1 to 25 parts by mass, more preferably 3 to 20 parts by mass in 100 parts by mass of the liquid crystal sealant. Such a liquid crystal sealant has a long working life since it has good moisture resistance and viscosity stability. In addition, since the moisture resistance is good, when applied to a liquid crystal display panel, a liquid crystal display panel having high adhesive strength between the cured liquid crystal sealant and the substrate and excellent display properties can be obtained. On the other hand, when the total amount exceeds 25 parts by mass, the viscosity stability is poor, and when it is less than 1 part by mass, curing may be insufficient.

  Moreover, it is preferable that it is 0.2 <= W2 / (W1 + W2) <= 0.8, when the compounding mass of (2) component is set to W1 and the compounding mass of (3) component is set to W2. More preferably, 0.4 ≦ W2 / (W1 + W2) ≦ 0.6. At this time, when a plurality of types of compounds are used as the components (2) and (3) for the preparation of the liquid crystal sealant, the total amount of the compounds used in each component is regarded as W1 and W2. Since such a liquid crystal sealant has a good viscosity stability, the pot life is prolonged, and when such a liquid crystal sealant is applied to a liquid crystal display panel, the adhesive strength between the cured liquid crystal sealant and the substrate is high. A liquid crystal display panel that is high and has excellent display properties and moisture resistance reliability can be obtained.

  In the liquid crystal sealant of the present invention, the total of the active hydrogen equivalents of the component (2) and the component (3) is 0.3 to 3.0 with respect to the epoxy equivalent of the component (1). preferable. The active hydrogen equivalent is an equivalent of hydrogen that can react with the epoxy groups of the components (2) and (3). Such an active hydrogen equivalent can be measured by NMR or the like, but can also be calculated from the charged amount of the material having a hydroxyl group.

  The liquid crystal sealant in which the active hydrogen equivalent is suitably adjusted has high reactivity between the epoxy resin and the curing agent. Therefore, when the liquid crystal sealant is cured, the curing proceeds in a short time, and the curing proceeds sufficiently, so that an uncured portion hardly remains. Here, when the active hydrogen equivalent exceeds 3.0, a large amount of the component (2) remains in the cured liquid crystal sealant, so that the water resistance of the cured product may be lowered. On the other hand, if the active hydrogen equivalent is less than 0.3, curing may not proceed well and an uncured portion may remain, and sufficient mechanical strength may not be obtained.

  As described above, regardless of the difference in melting point, the thermal latent curing agent used in the present invention is an amine-based thermal latent curing agent having an amino group. A liquid crystal sealant using such an amine-based heat latent curing agent has a very good viscosity stability at room temperature, and therefore has a long pot life and is preferably used as a one-pack type liquid crystal sealant. be able to. Here, the one-component type liquid crystal sealing agent is a mixture of a curing agent such as a heat-latent curing agent and a main component that is a curing component such as an epoxy resin, which is stable during storage. Refers to a liquid crystal sealant having good properties (storage stability).

  In addition, the amine-based heat latent curing agent has a higher active hydrogen in the amine-based heat latent curing agent than the (meth) acryl group in the component (6) and the component (7) described later when heated. Shows nucleophilic addition. As a result, the liquid crystal sealant using the amine-based latent heat curing agent has a high thermosetting property, and therefore has a very fast curing rate when heated. When such a liquid crystal sealant is used for the production of a liquid crystal display panel, curing proceeds without excess or deficiency even when a light-shielding area exists, and as a result, a liquid crystal display panel with good display properties can be obtained, Productivity is good because the curing time is shortened.

  Moreover, the liquid-crystal sealing compound of this invention may further contain (4) filler and (5) other additives. Thus, the liquid crystal sealing agent containing the components (1) to (5) is preferably used as a thermosetting liquid crystal sealing agent.

(4) Filler The filler according to the present invention is to improve the adhesion reliability of the liquid crystal sealant by controlling the viscosity of the liquid crystal sealant, improving the strength of the cured product obtained by curing the liquid crystal sealant, or suppressing the linear expansion. The filler used for the purpose of.

  The filler that can be preferably used in the present invention may be any known one, and is not particularly limited. Examples of fillers include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, aluminum oxide (alumina), zinc oxide, silicon dioxide, potassium titanate, kaolin, talc, Inorganic fillers such as asbestos powder, quartz powder, mica, glass fiber, talc, glass beads, sericite activated clay, bentonite, aluminum nitride, silicon nitride are included.

  The filler of the present invention can be obtained by copolymerizing polymethyl methacrylate, polystyrene, monomers constituting them and other monomers as long as the properties of the liquid crystal sealant are not impaired in addition to the inorganic fillers described above. Also known organic fillers such as copolymers, polyester fine particles, polyurethane fine particles, rubber fine particles may be used.

  Among these, inorganic fillers are preferable from the viewpoint of improving the linear expansion coefficient and the shape retention of the seal pattern. Among such inorganic fillers, silicon dioxide and talc are more preferable because of their high UV transmittance. Regardless of inorganic or organic, the filler used in the liquid crystal sealing agent of the present invention may be graft-modified with an epoxy resin or a silane coupling agent.

  The shape of the filler is not particularly limited, and may be a regular shape such as a spherical shape, a plate shape, or a needle shape, or an atypical shape. The maximum particle size of the filler is preferably 6 μm or less, and more preferably 2 μm or less. The particle size of the filler can be measured by laser diffraction. If a liquid crystal sealant containing a filler having such a particle size is used in a method for producing a liquid crystal display panel, a liquid crystal cell with very good cell gap dimensional stability can be formed.

  It is preferable that the compounding quantity of a filler is 1-40 mass parts in 100 mass parts of liquid crystal sealing agents except a filler, More preferably, it exists in the range of 10-30 mass parts. Thus, the liquid crystal sealing agent in which the blending amount of the filler is adjusted has good applicability to the substrate. The filler may be used in combination with a photocurable resin. Thus, the liquid crystal sealing agent in which the filler and the photocurable resin are used in combination has good photocurability and is cured in a short time. Furthermore, since the width of the cell gap is kept substantially constant, the dimensional stability is good.

(5) Other additives The liquid crystal sealant of the present invention may contain additives as necessary. Examples of additives preferably used in the present invention include thermal radical polymerization initiators, coupling agents such as silane coupling agents, ion trapping agents, ion exchange agents, leveling agents, pigments, dyes, plasticizers, antifoaming agents. Is included. These additives may be used alone or in combination of two or more kinds depending on the application. Further, a spacer or the like may be included in order to secure a gap of the liquid crystal cell. The spacer may be included in the liquid crystal sealant, or may be used by previously applying to a substrate constituting the liquid crystal display panel.

  When preparing a thermosetting sealant, a solvent may be included in order to improve dispense applicability and screen printability. Such a solvent preferably has good compatibility with the epoxy resin as component (1), has a boiling point in the range of 140 to 220 ° C., and is further inert to the epoxy group. . Examples of such solvents include ketone, ether, and acetate solvents. You may use these individually or in combination of multiple types.

  In addition to the above components (1) to (5), the liquid crystal sealant of the present invention further comprises (6) an acrylic ester and / or methacrylic ester monomer, or an oligomer thereof, and (7) one molecule. A (meth) acryl-modified epoxy resin having at least one epoxy group and at least one (meth) acryl group, and (8) a radical photopolymerization initiator may be included. Such a liquid crystal sealant can be preferably used as a liquid crystal sealant that is cured by light and heat.

(6) Acrylic acid ester and / or methacrylic acid ester monomer, or oligomer thereof Examples of the acrylic acid ester monomer and / or methacrylic acid ester monomer or oligomer used in the present invention include the following. There is no particular limitation.

  Diacrylate and / or dimethacrylate such as polyethylene glycol, propylene glycol, polypropylene glycol; diacrylate and / or dimethacrylate of tris (2-hydroxyethyl) isocyanurate; 4 moles or more of ethylene oxide or propylene per mole of neopentyl glycol Diacrylate and / or dimethacrylate of diol obtained by addition of oxide; diacrylate and / or dimethacrylate of diol obtained by addition of 2 mole of ethylene oxide or propylene oxide to 1 mole of bisphenol A; 1 mole of trimethylolpropane Diol or triacrylate of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to Or di- or trimethacrylate; diacrylate and / or dimethacrylate obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A; tris (2-hydroxyethyl) isocyanurate triacrylate and / or Trimethylolpropane triacrylate and / or trimethacrylate, or oligomer thereof; pentaerythritol triacrylate and / or trimethacrylate, or oligomer thereof; polyacrylate and / or polymethacrylate of dipentaerythritol; tris (acryloxyethyl) isocyanate Nuproate; caprolactone-modified tris (acryloxyethyl) isocyanurate; caprolact Modified tris (methacryloxyethyl) isocyanurate; polyacrylate and / or polymethacrylate of alkyl-modified dipentaerythritol; polyacrylate and / or polymethacrylate of caprolactone-modified dipentaerythritol; neopentyl glycol diacrylate and / or dihydroxy hydroxypivalate Caprolactone modified hydroxypivalate neopentyl glycol diacrylate and / or dimethacrylate; ethylene oxide modified phosphate acrylate and / or dimethacrylate; ethylene oxide modified alkylated phosphate acrylate and / or dimethacrylate; neopentyl glycol, trimethacrylate Methylolpropane, pentaerythritol oligoacrylate And / or oligomethacrylate.

  Examples of acrylic acid ester and / or methacrylic acid ester monomers or oligomers thereof include cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and triphenolmethane type. Epoxy resin obtained by reacting all epoxy groups such as epoxy resin, triphenolethane type epoxy resin, trisphenol type epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin with (meth) acrylate acid Resins that are fully (meth) acrylated are also included.

  These acrylic acid ester monomers and / or methacrylic acid ester monomers, or oligomers thereof may be used alone or in combination.

  When the component (6) is included in the liquid crystal sealant, the amount of the (1) epoxy resin is preferably 20 to 200 parts by mass with respect to 100 parts by mass of the component (6). If such a liquid crystal sealant is cured by light or heat, a cured product having a high glass transition temperature (Tg) can be obtained. The Tg of the cured liquid crystal sealant can be measured with a dynamic viscoelasticity measuring device (DMA). For the purpose of obtaining a high-purity liquid crystal sealant, it is preferable to use a component (6) that has been highly purified by a water washing method or the like.

(7) (Meth) acryl-modified epoxy resin The (meth) acryl-modified epoxy resin of the present invention refers to a compound obtained by reacting an epoxy resin with (meth) acrylate. Examples of such compounds include (a) a compound having both a (meth) acryl group and an epoxy group in one molecule, and (b) a compound in which a polymer of (meth) acrylate is dispersed in a base material such as an epoxy resin. Is included.

  Examples of the compound (a) having both a (meth) acrylic group and an epoxy group in one molecule include an epoxy resin such as a bisphenol type epoxy resin or a novolac type epoxy resin, and (meth) acrylic acid or phenyl methacrylate. For example, a resin obtained by reacting under a basic catalyst is included. Since such a modified epoxy resin has both an epoxy group and a (meth) acryl group in the resin skeleton, it is excellent in compatibility with the component (1) of the liquid crystal sealant. Therefore, a cured product having a high glass transition temperature (Tg) and high adhesiveness is obtained.

  Examples of epoxy resins that can be used as raw materials for modified epoxy resins include cresol novolac type epoxy resins, phenol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, triphenolmethane type epoxy resins, and triphenolethane type epoxies. Resin, trisphenol type epoxy resin, dicyclopentadiene type epoxy resin, and biphenyl type epoxy resin are included. The modified epoxy resin is preferably highly purified by a molecular distillation method, a washing method, or the like.

  Examples of the compound in which the polymer of (b) (meth) acrylate is dispersed in a base material such as an epoxy resin include an acrylic rubber-modified epoxy resin obtained by acrylic modification of an epoxy resin. As such an acrylic rubber-modified epoxy resin, a known and commercially available resin may be used, or an arbitrarily synthesized resin may be used.

(8) Photoradical polymerization initiator The photoradical polymerization initiator of the present invention refers to a compound that generates radicals by light. Examples of photo radical polymerization initiators include benzoin compounds, acetophenones, benzophenones, thioxanthones, α-acyloxime esters, benzoins, benzoin ethers, phenylglyoxylates, benzyls, azo compounds, Anthraquinones, diphenyl sulfide compounds, acylphosphine oxide compounds, organic dye compounds, and iron-phthalocyanine compounds are included, but are not particularly limited, and known photopolymerization initiators can be used. You may use these individually or in combination of multiple types.

  Since the liquid crystal sealant containing such a radical photopolymerization initiator can be temporarily cured by photocuring, the work process for manufacturing a liquid crystal display panel is facilitated. Moreover, it is preferable that the compounding quantity of (8) component is 0.01-5 mass parts with respect to 100 mass parts of liquid crystal sealing agents. It can be hardened in a short time by irradiating light that the compounding quantity of radical photopolymerization initiator is 0.01 mass part or more. When the blending amount is 5 parts by mass or less, a coated product of the liquid crystal sealant is good, and a cured product that is uniformly cured by light irradiation is obtained.

[Method for preparing liquid crystal sealant]
The method for preparing the liquid crystal sealant of the present invention is not particularly limited, and a known technique can be used. Examples of means for mixing each component of the liquid crystal sealant include a double-arm stirrer, a roll kneader, a twin screw extruder, a ball mill kneader, and a planetary stirrer, but are not particularly limited and are publicly known. Any kneading machine may be used. The liquid crystal sealant suitably mixed by any method is filtered through a filter to remove impurities. And after a vacuum defoaming process, a glass bottle or a plastic container is hermetically filled and stored and transported as necessary.

  Next, the manufacturing method of the liquid crystal display panel of this invention is demonstrated. The liquid crystal sealing agent of the present invention described above can be applied to both a liquid crystal injection method and a liquid crystal dropping method. Below, the manufacturing method of the liquid crystal display panel of this invention regarding a liquid crystal injection system and a liquid crystal dropping system is demonstrated one by one.

[Method of manufacturing liquid crystal display panel by liquid crystal injection method]
The method for producing a liquid crystal display panel by the liquid crystal injection method of the present invention is a method for producing a liquid crystal display panel produced by bonding two opposing substrates together through a liquid crystal sealant. A step of preparing a substrate having a frame-like display region formed so as to surround the pixel array region by the liquid crystal sealant and provided with a liquid crystal injection port; and (2) 2 through the liquid crystal sealant. A step of forming a liquid crystal cell between the substrates by stacking the substrates and then bonding the substrates together by heating and pressing, and (3) injecting liquid crystal into the liquid crystal cell from the injection port And (4) sealing the injection port of the liquid crystal cell into which the liquid crystal is injected with a sealing agent for sealing.

  In the step (1), a liquid crystal sealant is applied to one of the two substrates, and a substrate on which a frame-shaped display region is arranged is prepared. Here, an injection port for injecting liquid crystal is formed in the frame-shaped display region.

  Examples of the two substrates used in the liquid crystal display panel of the present invention include a glass substrate on which TFTs are formed in a matrix, a substrate on which color filters and a black matrix are formed. Examples of the material of the substrate include glass, polycarbonate, polyethylene terephthalate, polyethersulfone, and plastic such as PMMA. On the surface of such a substrate, a transparent electrode typified by indium oxide, an alignment film typified by polyimide, and other inorganic ion shielding films may be applied.

  As the liquid crystal sealant, those according to the present invention are preferably used. The liquid crystal sealing agent not only forms a frame such as a display area, but also acts as an adhesive for bonding two substrates at a predetermined interval. When manufacturing a liquid crystal display panel by a liquid crystal injection method, a thermosetting sealant is particularly preferable among the liquid crystal sealants according to the present invention.

  The method for applying the liquid crystal sealant on the substrate is not particularly limited. Examples of such application methods include screen printing and application by a dispenser. Note that the liquid crystal sealant may be applied to the surface of each substrate.

  The substrate after the liquid crystal sealant is applied is subjected to a precure treatment as necessary. Precure treatment refers to preliminary drying for pre-curing the liquid crystal sealant. There are no particular limitations on the heating temperature or processing time required for the precure treatment.

  However, when the liquid crystal sealant contains a solvent, at least 95% by mass of the total amount of the solvent in the liquid crystal sealant is removed, and the thermal activation temperature of the thermal latent curing agent contained in the liquid crystal sealant It is preferable to set the heating temperature to be as follows. Desolvation means removing the solvent from the liquid crystal sealant by evaporating it. From such a point of view, preferable heating conditions for the precure treatment include a heating temperature of 60 to 110 ° C. and a heating time of 5 to 60 minutes.

  In the pre-curing treatment, it is preferable to shorten the heating time as the heating temperature is increased so that the properties of the liquid crystal sealant are not impaired by heat. At this time, even when the heating temperature is set to 110 ° C. or higher, the liquid crystal sealant can be removed from the solvent, but the curing proceeds more than necessary, and the width of the cell gap may change. Therefore, the heating conditions during the precure treatment are appropriately determined according to the type of each component constituting the liquid crystal sealant.

  In the step (2), the substrate on which the liquid crystal sealing agent has been preliminarily dried and the other substrate are overlapped and aligned, and then heated and pressed. Since the liquid crystal sealant is cured by heat-pressing, the two substrates are bonded to each other through the liquid crystal sealant. At this time, the thickness of the liquid crystal sealant after bonding the substrates to each other is made uniform within a range of 1.5 to 7.0 μm by appropriately adjusting the pressurizing conditions at the time of heating and pressing. Is preferred.

  There are no particular limitations on the heating conditions when the substrates are heat-pressed. Generally, when the heating condition is set to 0.5 to 24 hours in a temperature range of 100 to 160 ° C., the liquid crystal sealant can be suitably cured.

  Moreover, when heat-pressing two substrates, a single wafer heat press may be used. The single-wafer heat press refers to a heat press that bonds two substrates one by one. Examples of such single-wafer heat presses include vacuum single-wafer heat presses that can be heated under vacuum, and rigid single-wafer heat that is forcibly heated and pressed via a hot plate under atmospheric pressure. A press machine is included.

  When two substrates are bonded together using a single-wafer heat press, first, the two stacked substrates are temporarily bonded by heating and pressing at 100 to 160 ° C. for about 2 to 10 minutes. Next, the pressure of the press machine is released, and the two substrates bonded from the press machine are taken out. Subsequently, the liquid crystal sealant is completely cured in a heating oven maintained at a substantially constant temperature. Here, the step of heating the liquid crystal sealant may be performed in two or more stages. Further, instead of the single-wafer press machine, a liquid crystal display cell may be manufactured by a multi-sheet batch heating and pressing adhesive method.

  In the step (3), liquid crystal is injected into the liquid crystal cell from the injection port. The liquid crystal may be appropriately determined according to the volume of the cell and is not particularly limited.

  In the step (4), the inlet of the liquid crystal cell into which the liquid crystal has been injected is sealed with a sealing agent for sealing. Examples of the sealant for sealing include a two-component curable sealant and an ultraviolet curable sealant, but are not particularly limited.

[Method of manufacturing liquid crystal display panel by liquid crystal dropping method]
The method for producing a liquid crystal display panel by the liquid crystal dropping method of the present invention is a method for producing a liquid crystal display panel produced by bonding two opposing substrates together through a liquid crystal sealant. A step of preparing a substrate having a frame-shaped display region formed so that the pixel array region is surrounded by the liquid crystal sealing agent; and (11) in the uncured display region or on the other substrate. A step of dropping the liquid crystal on the substrate, (12) a step of superimposing the substrate on which the liquid crystal has been dropped and the other substrate under reduced pressure, and (13) between the two superimposed substrates. Curing the liquid crystal sealant by heating.

  In the step (10), a substrate including a display area on a frame formed so that the pixel array area is surrounded by the liquid crystal sealant according to the present invention is prepared. The substrate used here and the method of applying a liquid crystal sealing agent to the substrate may be the same as those in the liquid crystal injection method, and are not particularly limited. Moreover, when manufacturing a liquid crystal display liquid crystal display panel by a liquid crystal dropping system, a light and a thermosetting sealing agent are used preferably.

  In the step (11), an appropriate amount of liquid crystal is dropped in an uncured frame serving as a display region or on the other substrate. This liquid crystal dropping is usually performed under atmospheric pressure. At this time, it is preferable to adjust the dropping amount of the liquid crystal according to the size of the frame so that the liquid crystal fits in the frame. When the liquid crystal is dropped into the frame in this manner, the capacity of the liquid crystal does not exceed the capacity of the empty cell surrounded by the frame and the substrate after bonding. Therefore, since excessive pressure is not applied to the frame, there is little possibility that the seal forming the frame is broken.

  In the step (11), the other substrate on which the liquid crystal is dropped means a substrate different from the substrate having the display region. In the case where liquid crystal is dropped onto a substrate on which such a seal is not disposed, the liquid crystal may be dropped at an arbitrary position on the other substrate that can serve as a display region when the substrates are overlapped with each other.

  In the step (12), the substrate on which the liquid crystal is dropped is superposed on the other substrate under reduced pressure. Here, superposition of the substrates may be performed using a vacuum bonding apparatus or the like, but is not particularly limited. Usually, in the liquid crystal dropping method, the substrates are superposed under reduced pressure. The reason for superposing under reduced pressure in this way is to bond the substrates together using a pressure difference.

  In the step (13), the liquid crystal sealant between the two superimposed substrates is cured. The curing treatment of the liquid crystal sealant is not particularly limited as long as it is appropriately determined according to the type of the curing agent. When a photocurable liquid crystal sealant is used, light irradiation such as ultraviolet rays is performed, and when a thermosetting liquid crystal sealant is used, heat treatment is appropriately performed.

Curing conditions such as the type of light irradiated for curing the liquid crystal sealant in the curing process, the irradiation time, or the temperature and time during heating may be appropriately selected according to the composition of the liquid crystal sealant used. . For example, in the case where the liquid crystal sealant is cured by light, the curing condition may be irradiated with ultraviolet rays within a range of 1000 to 18000 mJ under pressure. Further, when the liquid crystal sealant is cured by heating, the liquid crystal sealant can be sufficiently cured by heating at a heating temperature in the range of 110 to 140 ° C. with no pressure applied and heating for 1 hour.

  Regardless of the liquid crystal injection method and the liquid crystal dropping method, the liquid crystal display panel manufactured by combining the liquid crystal sealing agent of the present invention and the manufacturing method has good moisture resistance reliability. The present invention includes these liquid crystal display panels.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples according to the present invention. However, the present invention is not limited to the embodiment shown here.

  First, each component used for the preparation of the liquid crystal sealant in the examples and comparative examples will be described. In the following Examples and Comparative Examples, two types of liquid crystal sealants (liquid crystal sealants a and b) described later were appropriately selected and used. Here, the liquid crystal sealing agent a acts as a thermosetting sealing agent, and the liquid crystal sealing agent b acts as a light and thermosetting sealing agent.

(1) Epoxy resin As the epoxy resin, an o-cresol novolac type solid epoxy resin (EOCN-1020-75 manufactured by Nippon Kayaku Co., Ltd., softening point by ring ball method, 75 ° C., epoxy equivalent of 215 g / eq) was used.

(2) First thermal latent curing agent having a melting point of 150 ° C. or lower As the first thermal latent curing agent, (a) 2-phenylimidazole (manufactured by Adeka Hardener EH4346S ADEKA Corporation, melting point 125 ° C.) (B) Polyaminourea type (Fujicure FXE-1000 manufactured by Fuji Kasei Kogyo Co., Ltd., melting point 120 ° C.), (c) Amine adduct type (Adeka Hardener EH4357S ADEKA Co., Ltd., melting point 78 ° C.), (d) 1 , 3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (Amicure VDH manufactured by Ajinomoto Fine Techno Co., Ltd., 120 ° C .; solubility in 100 ml of water at 25 ° C. exceeding 100 g) is appropriately selected. Using.

(3) Second thermal latent curing agent having a melting point of 180 ° C. or higher As the second thermal latent curing agent, (a) diamide type (AH-154 manufactured by Ajinomoto Fine Techno Co., Ltd., melting point 200 ° C.) (B) Imidazole-based (Cureazole 2E4MZ-A, Shikoku Kasei Kogyo Co., Ltd., melting point 220 ° C.), (c) Dodecandiohydrazide (N-12, Nihon Finechem Co., Ltd., melting point 189 ° C .; 25 ° C. water 100 ml (D) Sebacic acid dihydrazide (SDH, Otsuka Chemical Co., Ltd., melting point 190 ° C.), (e) Fatty acid dicarboxylic acid (ADH Nihon Finechem Co., Ltd., melting point 181 ° C .; 25 ° C. water 100 ml) Five types having a solubility of 10 g) were appropriately used.

(4) Filler As filler, (a) amorphous silica (MU-120 manufactured by Shin-Etsu Chemical Co., Ltd.), (b) amorphous alumina (UA-5105 manufactured by Showa Denko KK), (c) inorganic sphere Three types of silica (Sea Foster S-30 manufactured by Nippon Shokubai Co., Ltd., average primary particle size 0.3 μm, specific surface area 11 m ² / g) were appropriately used.

(5) Other additives As other additives, a silane coupling agent (γ-glycidoxypropyltrimethoxysilane KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) was used.

(6) Acrylic acid ester and / or methacrylic acid ester monomer, or oligomers thereof (6) As components, bisphenol A type epoxy dimethacrylate (3000M manufactured by Kyoeisha Chemical Co., Ltd.) and bisphenol A type epoxy acrylate (EB- 3700 manufactured by Daicel Cytec Co., Ltd.) was appropriately selected and used.

(7) (Meth) acryl-modified epoxy resin As the (meth) acryl-modified epoxy resin, an acrylic rubber-modified epoxy resin obtained by acrylic modification of the epoxy resin obtained in Synthesis Example 1 below was used.

[Synthesis Example 1]
In a 2000 ml four-necked flask equipped with a stirrer, a gas introduction tube, a thermometer, and a cooling tube, 600 g of bisphenol A type epoxy resin (Epomic R-140P, Mitsui Chemicals), which is a liquid epoxy resin, and 12 g of acrylic acid Then, 1 g of dimethylethanolamine and 50 g of toluene were charged, and the mixture was heated and stirred at 110 ° C. for 5 hours in a dry air stream. Next, 350 g of butyl acrylate, 20 g of glycidyl methacrylate, 1 g of divinylbenzene, 1 g of azobisdimethylvaleronitrile, and 2 g of azobisisobutyronitrile are added to this mixture, and nitrogen is introduced into the reaction system. After reacting at 3 ° C. for 3 hours, it was further reacted at 90 ° C. for 1 hour. Finally, the prepared mixture was detolueneized under reduced pressure at 110 ° C. to obtain an acrylic rubber-modified epoxy resin.

(8) Photoradical polymerization initiator As the photoradical polymerization initiator, 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184 manufactured by Ciba Specialty Chemicals) was used.

  Furthermore, propylene glycol diacetate (manufactured by Dowanol PGDA Dow Chemical Co., Ltd.) was used as a solvent as required. In addition to the above, a monohydrazide thermal latent curing agent (manufactured by SMH Otsuka Chemical Co., Ltd., melting point 148 ° C .; solubility in 100 ml of water at 25 ° C. is less than 10 g) is used as appropriate. It was.

  In each example and comparative example, (i) viscosity stability of liquid crystal sealant, (ii) adhesive strength of thermosetting sealant, (iii) adhesive strength of light and thermosetting sealant, (iv) Measure and evaluate the display properties of liquid crystal display panels using thermosetting sealants and (v) display properties of liquid crystal display panels using light and thermosetting sealants. evaluated. Details of each measurement are shown below. Here, as a method for evaluating the viscosity stability of the liquid crystal sealant (i), the same method was used for thermosetting sealant, light, and thermosetting seal.

(I) Viscosity stability of liquid crystal sealant The viscosity value at 25 ° C of the liquid crystal sealant was measured using an E-type viscometer. The liquid crystal sealant used for viscosity measurement was sealed in a polyethylene container and stored at 25 ° C. for 5 days. Then, after a predetermined period of time, the viscosity value at 25 ° C. is measured with an E-type viscometer, and the viscosity value after the lapse of 25 ° C./5 days when the viscosity value before sealing is 100 based on the measured value. The rate of change was calculated. At this time, when the rate of change is less than 10%, the viscosity stability is extremely high (◎), and when it is 10% or more and less than 15%, the viscosity stability is high (◯), and the change exceeds 15%. In the case where there was, the viscosity stability was poor (x) and was evaluated in three stages.

(Ii) Adhesive strength of thermosetting sealant First, a liquid crystal sealant to which 1% by mass of a 5 μm glass fiber was added was screen-printed in a circular shape having a diameter of 1 mm on an alkali-free glass of 25 mm × 45 mm × 5 mm thick. , 90 ° C., 10 minutes pre-curing treatment. Next, the same glass paired with this substrate was bonded to a cross, fixed with a jig, and heat-treated at 120 ° C. for 60 minutes using an oven.

  Using a tensile tester (Model 210 manufactured by Intesco Corp.), the finished test piece was peeled in a direction parallel to the glass bottom surface with a tensile speed of 2 mm / min, and the plane tensile strength was measured. Here, the adhesive strength was evaluated in two stages according to the magnitude of the plane tensile strength. That is, when the tensile strength is 15 MPa or more, the adhesive strength is particularly high (◎), when the tensile strength is 10 MPa or more and less than 15 MPa, the adhesive strength is high (◯), and the tensile strength is less than 10 MPa. The adhesive strength was low (x).

  In addition, after a pressure cooker test was performed on a test piece manufactured by the same method as described above under the conditions of 121 ° C., 2 atm, 100% humidity, and 40 hours, the plane tensile strength was measured by the same method as described above, thereby applying pressure. The planar tensile strength before and after the cooker test was compared. When the tensile strength after the pressure cooker test is 10 MPa or more, the moisture-resistant adhesion reliability is particularly high (◎), and when the tensile strength is 7 MPa or more and less than 10 MPa, the moisture-resistant adhesion reliability is high (◯), When the tensile strength was less than 7 MPa, the moisture-resistant adhesion reliability was low (x).

(Iii) Adhesive strength of light and thermosetting sealant First, a liquid crystal sealant to which 1% by mass of a 5 μm glass fiber is added is screened in a circular shape with a diameter of 1 mm on an alkali-free glass of 25 mm × 45 mm × 5 mm thick. Printed and a pair of similar glasses stuck together in a cross. Next, an ultraviolet ray irradiation device (USHIO INC.) Was used to irradiate 100 mW / cm ² of ultraviolet rays at a place where a load was applied by sandwiching the two bonded substrates with clips. The test piece which hardened the liquid-crystal sealing compound only was produced. At this time, the irradiation energy of ultraviolet rays was 2000 mJ.

  The completed test piece was heat-treated at 120 ° C. for 60 minutes in a nitrogen atmosphere using an oven. The planar tensile strength of the completed test piece was measured using a tensile tester (Model 210 manufactured by Intesco Corporation). At this time, the measurement of the plane tensile strength, the evaluation of the measurement results, and the comparison of the plane tensile strength before and after the pressure cooker test were performed by the same method as the above-described thermosetting sealant.

(Iv) Display properties of a liquid crystal display panel using a thermosetting sealant On a 40 mm × 45 mm glass substrate (RT-DM88PIN EHC Co., Ltd.) provided with a transparent electrode and an alignment film, 5 μm glass fiber is 1 A frame type of 35 mm × 40 mm with a line width of 0.5 mm and a thickness of 50 μm was drawn using a thermosetting sealing agent added by mass%. At this time, a liquid crystal inlet was provided in the frame. For drawing, a dispenser (manufactured by Shotmaster Musashi Engineering) was used.

  The drawn thermosetting sealant was pre-cured and heated and dried for 10 minutes, and then the other glass substrate to be paired was superposed, and then fixed with a jig. Heat treatment for minutes was performed.

  Next, a liquid crystal material (MLC-11900-000 manufactured by Merck & Co., Inc.) corresponding to the internal volume of the cell after bonding is injected into the liquid crystal cell formed between the two substrates from the injection port. Then, such an inlet was sealed with a sealing agent (Structbond ES-302, manufactured by Mitsui Chemicals, Inc.) to obtain a liquid crystal display panel.

  Of the surface of the manufactured liquid crystal display panel, a deflection plate was attached to the front side, and a deflection plate with a reflection plate was attached to the rear side. The liquid crystal display panel was driven by applying a voltage of 5 V to the liquid crystal display panel with a DC power supply. At this time, it is visually observed whether the liquid crystal display function in the vicinity of the seal formed by the liquid crystal sealant functions normally from the beginning of driving, and the display properties of the liquid crystal display panel are evaluated in two stages according to the following criteria: did.

  The display of such a liquid crystal display panel is good (○) when the liquid crystal display function is exhibited until sealing, and from the vicinity of sealing to a position 0.3 mm away from the inside of the frame When the display function was not exhibited, the display property was markedly bad (x).

  In addition, the above-mentioned liquid crystal display panel was subjected to a pressure cooker test under the conditions of 121 ° C., 2 atm, humidity 100%, and 40 hours, and then the display performance of the liquid crystal display panel was evaluated in the same manner, whereby the pressure cooker The display properties of the liquid crystal display panel before and after the test were compared.

(V) Display property of liquid crystal display panel using light and thermosetting sealant 5 μm glass fiber on 40 mm × 45 mm glass substrate (RT-DM88PIN EHC Co., Ltd.) with transparent electrode and alignment film Using a light and a thermosetting sealant added with 1% by mass, a 35 mm × 40 mm frame was drawn with a line width of 0.5 mm and a thickness of 50 μm. For drawing, a dispenser (manufactured by Shotmaster Musashi Engineering Co., Ltd.) was used.

Next, a liquid crystal material (MLC-11900-000 manufactured by Merck & Co., Inc.) corresponding to the panel internal volume after pasting was precisely dropped with a dispenser. Subsequently, the two glass substrates were stacked so as to face each other under a reduced pressure of 90 Pa, fixed under a load, and further, 100 mW / cm using an ultraviolet irradiation device (USHIO INC.). ^The liquid crystal sealant was cured by irradiating the ultraviolet ray ² . At this time, the irradiation energy of ultraviolet rays was 2000 mJ. A metal halide lamp was used as the light source, and an ultraviolet integrated light meter (UVR-T35 Topcon Co., Ltd.) having a measurement wavelength range of 300 to 390 nm and a peak sensitivity wavelength of 365 nm was used for measuring the integrated light amount. . Further, after the liquid crystal sealing agent was cured by light, the liquid crystal sealing agent was further cured by heating at 120 ° C. for 60 minutes.

  A deflection film was pasted on both surfaces of the two bonded substrates to form a liquid crystal display panel. The liquid crystal display panel was driven by applying a voltage of 5 V to the liquid crystal display panel with a DC power supply device. At this time, whether or not the liquid crystal display function in the vicinity of the seal formed by the liquid crystal sealant functions normally from the beginning of driving was visually observed, and the display properties of the liquid crystal display panel were evaluated in two stages according to predetermined criteria. Here, since the reference | standard which evaluates the display property of a liquid crystal display panel is the same as the above-mentioned thermosetting sealing agent, detailed description is abbreviate | omitted.

  In addition, the above-mentioned liquid crystal display panel was subjected to a pressure cooker test under the conditions of 121 ° C., 2 atm, humidity 100%, 40 hours, and further, the display property of the liquid crystal display panel was evaluated in the same manner, before and after the pressure cooker test. We compared the display properties of liquid crystal display panels.

  Furthermore, the evaluation results performed for each liquid crystal sealant were tabulated and the characteristics of the liquid crystal sealant were comprehensively evaluated in three stages according to the following criteria. Here, in each evaluation result, when all or any of the viscosity stability, adhesiveness, and display property of the liquid crystal display panel is particularly good (◎), the properties of the liquid crystal sealant are particularly good (◎ In each evaluation result, when the viscosity stability, adhesiveness, and display properties of the liquid crystal display panel are all good (◯), the liquid crystal sealant has good characteristics (○). In the case where the viscosity stability, the adhesiveness, or the display property of the liquid crystal display panel is not preferable, that is, when there is even one X, the liquid crystal sealant has poor characteristics (X).

[Example 1]
(1) As a component, 25 parts by mass of O-cresol novolac epoxy resin (EOCN-1020-75 manufactured by Nippon Kayaku Co., Ltd.) and 15 mass of propylene glycol diacetate (Dawanol PGDA manufactured by Dow Chemical Co., Ltd.) as a solvent This was heated and dissolved in the part. Furthermore, 20 parts by mass of an acrylic rubber-modified epoxy resin of Synthesis Example 1 to be described later, and 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (Amure VDH-J Ajinomoto Fine Techno Co., Ltd.) as component (2) 9 parts by mass, (3) as component, 4 parts by mass of dodecandiohydrazide (N-12 made by Nippon Finechem), 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ')]-Ethyl-s-triazine (Cureazole 2E4MZ-A manufactured by Shikoku Kasei Kogyo Co., Ltd.), 2 parts by mass, (4) as component, amorphous silica (MU120 manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by mass 13 parts by mass of regular alumina (UA-5105 manufactured by Showa Denko), and as component (5), γ-glycidoxypropyltrimethoxysilane (KBM403 Shin-Etsu Chemical Co., Ltd.) 5 parts by mass) were added and premixed with a mixer. Subsequently, after kneading until the solid raw material became 5 μm or less using three rolls, the kneaded product was vacuum defoamed to prepare a thermosetting sealant.

[Example 2]
(3) A liquid crystal sealant was prepared in the same manner as in Example 1 except that the component was 4 parts by mass of sebacic acid dihydrazide (SDH).

[Example 3]
The blending amount of the component (2) is 2 parts by mass, and the component (3) is 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine ( A liquid crystal sealant was prepared in the same manner as in Example 1 except that Curesol 2E4MZ-A) was not used and dodecandiohydrazide (N-12) was 13 parts by mass.

[Example 4]
The blending amount of the component (2) is 13 parts by mass, and the component (3) is 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine ( A liquid crystal sealant was prepared in the same manner as in Example 1 except that Curesol 2E4MZ-A) was not used and dodecandiohydrazide (N-12) was 2 parts by mass.

[Example 5]
The component (2) is 9 parts by mass of 2-phenylimidazole (Adeka Hardener EH-4346S), and the component (3) is 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′). )]-Ethyl-s-triazine (Curazole 2E4MZ-A) was used, and a liquid crystal sealant was prepared in the same manner as in Example 1 except that 6 parts by mass of dodecanediohydrazide (N-12) was used. .

[Example 6]
(2) Component is 9 parts by mass of polyaminourea (Fujicure FXE-1000), and (3) component is 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)] — A liquid crystal sealant was prepared in the same manner as in Example 1 except that ethyl-s-triazine (Cureazole 2E4MZ-A) was not used and dodecandiohydrazide (N-12) was 6 parts by mass.

[Example 7]
Component (2) is 9 parts by mass of amine adduct system (Adeka Hardener EH-4357S), and component (3) is 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]. A liquid crystal sealant was prepared in the same manner as in Example 1 except that ethyl-s-triazine (Curazole 2E4MZ-A) was not used and dodecandiohydrazide (N-12) was changed to 6 parts by mass.

[Example 8]
A liquid crystal sealant was prepared in the same manner as in Example 1 except that the amount of the component (2) was 6 parts by mass and the component (3) was 9 parts by mass of fatty acid dicarboxylic acid (ADH).

[Example 9]
(1) As a component, 15 parts by mass of O-cresol novolac epoxy resin (EOCN-1020-75 manufactured by Nippon Kayaku Co., Ltd.) and 30 masses of bisphenol A type epoxy dimethacrylate (epoxy ester 3000M manufactured by Kyoeisha Chemical Co., Ltd.) This was heated and dissolved in the part to obtain a uniform solution. Next, after cooling this mixed solution, 20 parts by mass of bisphenol A type epoxy acrylate (EB3700 manufactured by Daicel Cytec Co., Ltd.), (8) 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure as photo radical polymerization initiator) 184 Ciba Peshatti Chemical Co., Ltd.) 2 parts by mass, and as component (2), 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (Amicure VDH-J Ajinomoto Fine Techno Co., Ltd.) 6 2 parts by mass of imidazole (Cureazole 2E4MZ-A, Shikoku Kasei Kogyo Co., Ltd.), and 4 parts by mass of dodecandiohydrazide (N-12 Nihon Finechem Co., Ltd.), (4) As a component, spherical silica (Sea Foster S-30 manufactured by Nippon Shokubai Co., Ltd.) 20 quality Parts, (5) as a component, .gamma.-glycidoxypropyltrimethoxysilane (KBM403 manufactured by Shin-Etsu Chemical Co.) 1 part by weight was added and pre-mixed in a mixer. Furthermore, kneading with 3 rolls until the solid raw material is 5 μm or less, filtering with a filter having a mesh opening of 10 μm (MSP-10-E10S ADVANTEC Co., Ltd.), and then performing vacuum defoaming treatment for light and thermosetting. Liquid crystalline sealant was prepared.

[Example 10]
(3) A liquid crystal sealant was prepared in the same manner as in Example 9 except that 4 parts by mass of sebacic acid dihydrazide (SDH) was used instead of dodecanediohydrazide (N-12).

[Example 11]
The liquid crystal was the same as in Example 9 except that the amount of the component (2) was 2 parts by mass and the component (3) was 10 parts by mass of dodecanediohydrazide (N-12 made by Nippon Finechem Co., Ltd.). A sealant was prepared.

[Example 12]
A liquid crystal sealant was prepared in the same manner as Example 9 except that the amount of the component (2) was 10 parts by mass and the component (3) was 2 parts by mass of dodecanediohydrazide (N-12).

[Example 13]
The liquid crystal seal was the same as in Example 9 except that (2) component was 6 parts by mass of 2-phenylimidazole (Adeka Hardener EH4346S) and component (3) was 6 parts by mass of dodecandiohydrazide (N-12). An agent was prepared.

[Example 14]
A liquid crystal seal was prepared in the same manner as in Example 9, except that (2) component was 6 parts by mass of polyaminourea (Fujicure FXE-1000) and component (3) was 6 parts by mass of dodecanediohydrazide (N-12). An agent was prepared.

[Example 15]
(2) The liquid crystal seal was the same as in Example 9 except that the component was 6 parts by mass of an amine adduct system (Adeka Hardener EH4357S) and 6 parts by mass of dodecanediohydrazide (N-12 made by Nippon Finechem Co., Ltd.). An agent was prepared.

[Example 16]
(2) Component is 6 parts by mass of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (Amicure VDH), (3) component is 5 parts by mass of diamide (AH-154), fatty acid dicarboxylic acid ( ADH) A liquid crystal sealant was prepared in the same manner as in Example 9 except that the amount was 6 parts by mass.

[Comparative Example 1]
The same as Example 1 except that (3) component was not used and (2) component was changed to 15 parts by mass of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (amicure VDH). A liquid crystal sealant was prepared.

[Comparative Example 2]
A liquid crystal sealant was prepared in the same manner as Example 1 except that the component (2) was not used and the component (3) was (d) 15 parts by mass of sebacic acid dihydrazide (SDH).

[Comparative Example 3]
(2) Component is 9 parts by mass of monohydrazide thermal latent curing agent (SMH), (3) 2 parts by mass of imidazole (Cureazole 2E4MZ-A), and 4 parts by mass of dodecanediohydrazide (N-12) A liquid crystal sealant was prepared in the same manner as in Example 1 except that.

[Comparative Example 4]
A liquid crystal sealant was prepared in the same manner as in Example 9 except that the component (3) was not used and the component (2) was changed to 12 parts by mass.

[Comparative Example 5]
(2) No component is used, and (3) component is sebacic acid dihydrazide (SDH) 12 parts by mass, (4) component filler is 2 parts by mass, (5) component is 5 parts by mass, (6) A liquid crystal sealant was prepared in the same manner as in Example 9 except that 20 parts by mass of epoxy dimethacrylate and 15 parts by mass of epoxy acrylate were used.

[Comparative Example 6]
(2) Component is 6 parts by mass of monohydrazide thermal latent curing agent (SMH), (3) Component is 2 parts by mass of imidazole (Cureazole 2E4MZ-A), 4 parts by mass of dodecandiohydrazide (N-12) Furthermore, the same as Example 9 except that (4) component was 2 parts by mass, (5) component was 5 parts by mass, and (6) component was 20 parts by mass of epoxy dimethacrylate and 15 parts by mass of epoxy acrylate. A liquid crystal sealant was prepared.

  Tables 1 to 3 collectively show the components, blending amounts and evaluation results of the liquid crystal sealant used in each example and comparative example.

  As is clear from Tables 1 and 2, the liquid crystal sealants of Examples 1 to 16 to which the present invention is applied have the above-described viscosity stability, adhesive strength, and display properties of liquid crystal display panels manufactured using the same. It was confirmed that it was excellent.

  On the other hand, in the case of a liquid crystal sealant comprising one kind of thermal latent curing agent and epoxy resin as constituent components, as is clear from the results of the comparative examples shown in Table 3, it is compared with the examples. As a result, viscosity stability, adhesive strength, and display properties of the liquid crystal display panel are deteriorated. It was also confirmed that various properties such as viscosity stability deteriorated when a monohydrazide compound was used as the thermal latent curing agent. From the above results, it is apparent that among the hydrazide compounds, a dihydrazide-based thermal latent curing agent, not a monohydrazide-based compound, is suitable for the liquid crystal sealant.

  Since the liquid crystal sealing agent of the present invention uses two types of thermal latent curing agents having different melting points, the curing rate is high and the moisture resistance is high. Moreover, since the viscosity stability is kept high for a long time, the pot life is long. When such a liquid crystal sealant is applied to a liquid crystal display panel, since the adhesive strength between the cured liquid crystal sealant and the substrate is increased, a liquid crystal display panel having high moisture resistance reliability and excellent display properties can be obtained. Therefore, the liquid crystal sealant of the present invention is also useful as an adhesive for various optical devices including liquid crystal display panels.

  This application claims priority based on application number JP2006-213939, filed Aug. 4, 2006. All the contents described in the application specification are incorporated herein by reference.

Claims (11)

(1) an epoxy resin;
(2) a first thermal latent curing agent having a melting point of 150 ° C. or lower;
(3) a second thermal latent curing agent having a melting point of 180 ° C. or higher,
The component (2) is one or more thermal latent curing agents selected from the group consisting of dihydrazide-based, imidazole-based, amine adduct-based, polyamine-based, and polyaminourea-based thermal latent curing agents,
The liquid crystal sealing agent in which the component (3) is one or more thermal latent curing agents selected from the group consisting of dihydrazide-based, imidazole-based, and diamide-based thermal latent curing agents.   The liquid crystal sealant according to claim 1, wherein the component (2) and the component (3) are dihydrazide-based thermal latent curing agents.   The liquid crystal sealant according to claim 1, wherein the solubility of the component (3) in 100 ml of water at 25 ° C is 20 g or less. The liquid crystal sealant according to claim 1, wherein the component (3) is a compound represented by the following general formula (A).

However, R in the general formula (A) represents an alkylene group having 8 or more carbon atoms.   The liquid crystal sealant according to claim 1, wherein the liquid crystal sealant is a one-component type in which the components (1) to (3) are uniformly mixed.   2. The liquid crystal sealant according to claim 1, wherein the total amount of the component (2) and the component (3) is 1 to 25 parts by mass with respect to 100 parts by mass of the liquid crystal sealant.   The liquid crystal sealant according to claim 1, wherein 0.2 ≦ W2 / (W1 + W2) ≦ 0.8, where W1 is a blending mass of the component (2) and W2 is a blending mass of the component (3). .   2. The liquid crystal sealant according to claim 1, wherein the total of active hydrogen equivalents of the component (2) and the component (3) is 0.3 to 3.0 with respect to the epoxy equivalent of the component (1). In the manufacturing method of a liquid crystal display panel manufactured by bonding two substrates facing each other through a liquid crystal sealant,
Preparing a substrate having a frame-shaped display region formed so that the pixel array region is surrounded by the liquid crystal sealant according to claim 1 and provided with a liquid crystal injection port;
A process of forming a liquid crystal cell between the two substrates by laminating the two substrates by heating and pressing after laminating the two substrates via the liquid crystal sealant;
Injecting liquid crystal into the liquid crystal cell from the injection port;
Sealing the injection port of the liquid crystal cell into which the liquid crystal has been injected with a sealing agent for sealing;
A method for manufacturing a liquid crystal display panel comprising: In the manufacturing method of a liquid crystal display panel manufactured by bonding two substrates facing each other through a liquid crystal sealant,
Preparing a substrate having a frame-shaped display region formed so that the pixel array region is surrounded by the liquid crystal sealant according to claim 1;
Dropping the liquid crystal in the uncured display area or on the other substrate;
A step of superimposing the substrate onto which the liquid crystal has been dropped and the other substrate under reduced pressure;
Curing the liquid crystal sealant between the two superimposed substrates by heating;
A method for manufacturing a liquid crystal display panel comprising:
The liquid crystal display panel obtained by the manufacturing method of the liquid crystal display panel of Claim 9 or 10.