JPH09241603A - Sealing composition for liquid crystal display element and liquid crystal display element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having high reliability and giving a liquid crystal display element having an excellent displaying property by blending a crown ether as an essential component into a sealing material composition composed of a thermosetting resin, a hardener and an inorganic filler as main components. SOLUTION: This sealing composition is composed of a one-pack type or two-pack type adhesive composition containing (A) a thermosetting resin (preferably an epoxy resin), (B) a hardener (e.g. a hardener of an amine-based or an imidazole-based, etc.) and (C) an inorganic filler (preferably alumina or silica) as main components and further (D) a macrocyclic polyether (crown ether) as an essential component. As the component D, a synthetic substance such as 15-crown-5, 18-crown-6 or dibenzo-18-crown-6 is exemplified.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a sealing material composition for a liquid crystal display device and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have become widespread due to their features such as light weight, thin shape, and low power consumption. The liquid crystal display element has a structure in which the liquid crystal is sandwiched between glass or plastic substrates, and the periphery is sealed with an adhesive so that the liquid crystal does not leak outside. Generally, this is a seal for the liquid crystal display element. It is called a material (abbreviation of liquid crystal sealing material).

At present, an epoxy resin and a cation-curable or radical-curable photo-curable resin are widely used as the liquid crystal sealing material, but they are more excellent in electrical reliability than the current one in order to improve display characteristics of liquid crystal display elements. Liquid crystal sealing material is required. Specifically, when a sealing material with insufficient characteristics is used, display defects (such as the burning of characters, liquid crystal alignment failure, blurring of character boundaries, etc.) occur on the liquid crystal panel near the sealing material. However, the reliability as a liquid crystal display element is low.

SUMMARY OF THE INVENTION The present invention provides a sealing material for a liquid crystal display element, which improves the display characteristics of the liquid crystal display element as compared with a conventional sealing material, and a liquid crystal display element using the same.

[0004]

The present invention is a thermosetting resin,
A sealant for a liquid crystal display device, characterized in that a macrocyclic polyether (hereinafter referred to as a crown ether) is an essential component in a one-pack type and a two-pack type adhesive composition containing a curing agent and an inorganic filler as main components. Material composition.

The crown ether used as an essential component in the present invention is known to have a function of forming a complex (hereinafter referred to as cryptate) with various inorganic and organic cations and neutralizing the electric charge. It was found that the display characteristics of the liquid crystal display device are remarkably improved by adding this as an essential component to the liquid crystal sealing material composition, and the present invention has been accomplished.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal sealing material plays a role of preventing the liquid crystal from leaking to the outside by bonding and fixing two substrates made of glass and plastic. In order to eliminate the display defects due to the sealing material, efforts have been made to improve the purity of the resin, the curing agent, the accelerator, the filler, the solvent, etc. used in the sealing material. Specifically, it is reduction of ionic impurities. However, even if the ionic impurities are reduced in this way, when the LCD is driven under high temperature and high humidity, a display defect still occurs in the vicinity of the sealing material, and therefore it is not an essential solution. In other words, it is essential not only to reduce the ionic impurities in the raw materials, but also to prevent the ions generated during the curing of the sealing material from flowing into the liquid crystal cell due to changes in the external environment such as high temperature and high humidity. Is. The present inventor tried to blend crown ether into the composition of the sealing material, and earnestly studied the display characteristics of the liquid crystal display device using the sealing material. As a result, the crown ether captures the outflowing ions in the cured product of the sealing material to neutralize the charge, and the cryptate is larger than the distance between the cross-linking points of the cured product of the sealing material. It was found that even if there was a change, it stopped in the cured material of the sealing material. As a result, they have found that it is possible to significantly improve the display characteristics of a liquid crystal display device using such a sealing material.

As a result of intensive studies made by the present inventors from such a point, it has a sufficiently high reliability as a sealing material for liquid crystal display devices by adding crown ether as an essential component in the sealing material composition. It has been found that it is possible to obtain a liquid crystal display device having good display characteristics.

The crown ether used is not particularly limited, and examples thereof include aliphatic crown ether, aromatic crown ether, alicyclic crown ether, hetero group crown ether, cyclic polyether ester, aziridine cyclic oligomer, Cyclic polyamine,
Cyclic polysulfide, aliphatic azacrown ether, aromatic azacrown ether, alicyclic azacrown ether, heterocyclic azacrown ether, aliphatic thiacrown ether, aromatic thiacrown ether, alicyclic thiacrown ether, heterocycle Group thiacrown ether, aliphatic cyclic azathia ether, aliphatic cyclic azathia crown ether, aromatic azathia crown ether,
Heterocyclic azathia crown ether, separated bicyclic crown ether, C-bridgehead bicyclic crown ether, N bridgehead bicyclic crown ether, 4 N bridgehead spherical cryptands, N Bicyclic azacrown ether with bridgehead, Bicyclic azacrown ether with N as bridgehead, Bicyclic polythiaether with N as bridgehead, N
There is a bicyclic thiacrown ether with a bridgehead.
Further, the amount of crown ether added when blended in the sealant is not particularly limited, and the compounds described above may be used alone or in combination of two or more.

The epoxy resin used is not particularly limited. For example, bisphenol A type epoxy resin, alkyl-substituted bisphenol A type epoxy resin, bisphenol F type epoxy resin, alkyl substituted bisphenol F type epoxy resin, bisphenol S type epoxy resin. Resin, glycidyl amine type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin, urethane Modified epoxy resin etc. are available.

The curing agent is not particularly limited, and is generally used as a curing agent for epoxy resins such as amine curing agents, imidazole curing agents, dicyandiamide, hydrazide curing agents, acid anhydride curing agents, and phenol curing agents. A curing agent or the like can be used, and these microencapsulated curing agent, adduct-type curing agent or the like can be used to further improve the storability, and a curing accelerator can also be used in combination therewith. As the curing accelerator, phosphorus compounds,
Imidazole compounds, urea compounds, dibasic acid compounds, DBU salts and the like are generally used.

Examples of inorganic fillers include carbonates, sulfates, alumina, silica, titanium oxides of various metals,
Examples thereof include potassium titanate, and among these, it is preferable to use one kind or two or more kinds of alumina and silica in combination from various points. Further, the amount of the inorganic filler added is 3 to 5 out of the total composition in view of workability such as printability.
It is preferably 0% by weight.

If necessary, a solvent may be added for the purpose of adjusting the viscosity of the sealing material composition and uniformly mixing the components.
The solvent used is also not particularly limited, but for example n
-Hydrocarbon solvents such as hexane, n-decane and cyclohexane, aromatic hydrocarbon solvents such as benzene, toluene and xylene, ester solvents such as butyl acetate and benzyl acetate, methyl cellosolve, butyl cellosolve, methyl carbitol and ethyl. Polyhydric alcohols such as carbitol, butyl carbitol, methyl cellosolve acetate, ethylene glycol, diethylene glycol and diglyme, and their derivatives are used alone or in combination of two or more. From the viewpoint of printability and the like, the amount of the solvent added is preferably 2 to 50% by weight based on all components.

Further, a coupling agent, a defoaming agent, a leveling agent and the like may be added in addition to the above-mentioned epoxy resin, curing agent, inorganic filler and crown ether which are essential components in the present invention. When preparing the sealant composition for a liquid crystal display device of the present invention, it is preferable to sufficiently knead the components using a three-roll roll or the like in order to uniformly mix the components.

As a method for producing a liquid crystal display element using the sealant composition for a liquid crystal display element of the present invention, there are generally the following methods. First, a seal pattern is formed on one of the glass substrate and the plastic substrate on which the liquid crystal alignment layer is formed by a process such as screen printing, preliminarily dried by a dryer or the like, and then the other substrate is attached, and if necessary, Pressurize and heat cure in a drying oven or the like. Preliminary drying is suitable at 50 to 120 ° C. for 5 to 60 minutes, and heat curing is suitable at 100 to 200 ° C. for about 15 to 180 minutes. Further, in order to maintain the gap between the two substrates, the sealing material may contain a spherical or rod-shaped spacer having a predetermined diameter. Liquid crystal is injected into the bonded substrates, and the injection port is sealed with UV curable resin or the like to form a liquid crystal display element.

[0015]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1 As an epoxy resin, a bisphenol A type epoxy resin (produced by Yuka Shell Epoxy Co., Ltd.,
Epicoat 828) 80 parts by weight, bisphenol A type epoxy resin (Okaka Shell Epoxy Co., Epicoat 10
01) 20 parts by weight, 10 parts by weight of adipic dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) as a curing agent, and amorphous silica (manufactured by Nippon Aerosil Co., Ltd., Aerosil R-97) as an inorganic filler.
2) 5 parts by weight, spherical silica (Admatex, SO
-C4) 20 parts by weight, ethyl carbitol 1 as a solvent
3 parts by weight, 15-crown-5 as crown ether
(Synthetic product) 0.1 part by weight was mixed by stirring, and further sufficiently kneaded with a three-roll to obtain an adhesive composition.

Next, 1% of a spherical silica spacer having a diameter of 5 μm was mixed with this adhesive composition to prepare a liquid crystal cell in the following manner. (Screen printing) A square pattern having a line width of 0.3 mm was screen-printed on a glass substrate with ITO (square having a side of 3 cm) on which an alignment film was formed using a 300 mesh plate. (Preliminary Drying) Preliminary drying was performed in a hot air dryer at 90 ° C. for 30 minutes. (Adhesion / Curing by heat) An ITO-attached glass substrate having an alignment film formed thereon is attached so that the orientation direction is 90 degrees with respect to the orientation treatment direction of the substrate on which the sealing material is printed.
170 ℃ / in a hot air dryer with a pressure of 1kg / cm ²
It was cured by heating for 120 minutes. (Liquid crystal injection / sealing) Fluorine-based liquid crystal (Merck, ZLI
-4792), and the inlet was sealed with an acrylic UV curable resin.

The following items were evaluated for evaluation. (Condition 1) 10 in a high temperature and high humidity tank set at 60 ° C / 90%
Leave the liquid crystal display element for 0 hours (condition 2) Leave the liquid crystal display element in a dryer set at 40 ° C. for 100 hours, treat the liquid crystal display element under the above two conditions, and then
A rectangular wave of 3 V was applied, and the display unevenness in the vicinity of the sealing material was evaluated. The evaluation results are shown in Table 1.

Example 2 As the epoxy resin, a bisphenol A type epoxy resin (produced by Yuka Shell Epoxy Co., Ltd.,
Epicoat 828) 40 parts by weight, bisphenol A type epoxy resin (Okaka Shell Epoxy Co., Epicoat 10
01) 30 parts by weight, o-cresol novolac type epoxy resin (Sumitomo Chemical Co., Ltd., ESCN-195LB) 10 parts by weight, glycidyl amine type epoxy resin (Okaka Shell Epoxy Co., Epicoat 604) 20 parts by weight, as a curing agent 25 parts by weight of PN-23 (manufactured by Ajinomoto Co.), amorphous silica as an inorganic filler (Aerosil R manufactured by Nippon Aerosil Co., Ltd.)
-972) 5 parts by weight, alumina (Showa Denko KK, UA-
5055) 20 parts by weight, 18-as crown ether
Crown-6 (synthetic product) 0.4 part by weight, dibenzo-18
-Stir-mix 0.5 part by weight of Crown-6 (synthetic product),
Further, the mixture was sufficiently kneaded with a three-roll to obtain an adhesive composition. A 1% spherical silica spacer having a diameter of 5 μm was mixed with this adhesive composition to prepare a liquid crystal cell in the same manner as in Example 1. The evaluation results are as shown in Table 1.

Example 3 As an epoxy resin, 50 parts by weight of a dicyclopentadiene type epoxy resin (HP-7200, manufactured by Dainippon Ink and Chemicals, Inc.), a bisphenol A type epoxy resin (produced by Yuka Shell Epoxy, Epicoat 8)
28) 50 parts by weight, 100 parts by weight of phenol novolac resin (TD-2131 manufactured by Dainippon Ink and Chemicals) as a curing agent, 3 parts by weight of PN-23 (manufactured by Ajinomoto Co.) as a curing accelerator, and amorphous silica as an inorganic filler. (Aerosil R-972 manufactured by Nippon Aerosil Co., Ltd.) 5 parts by weight, spherical silica (SO-C4 manufactured by Admatex Co.) 20 parts by weight, ethyl carbitol 13 parts by weight as a solvent, and diamino-dibenzo-18-crown as a crown ether. -6 (synthetic product) (0.6 parts by weight) was stirred and mixed, and further thoroughly kneaded with a three-roll mill to obtain an adhesive composition. A 1% spherical silica spacer having a diameter of 5 μm was mixed with this adhesive composition to prepare a liquid crystal cell in the same manner as in Example 1. The evaluation results are as shown in Table 1.

(Example 4) As an epoxy resin, a naphthalene type epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc., HP
-4032) 40 parts by weight, bisphenol A type epoxy resin (Eikato Shell Epoxy Co., Epicoat 834) 5
0 parts by weight, 10 parts by weight of o-cresol novolac type epoxy resin (ESCN-195LB manufactured by Sumitomo Chemical Co., Ltd.), 8 parts by weight of adipic acid dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) as a curing agent, and amorphous silica (Japan) Aerosil Co., NAX50) 5 parts by weight, spherical silica (Admatex Co., SO-C4) 15 parts by weight, methyl carbitol as solvent 20 parts by weight, crown ether diaza-12-crown-4 (synthetic product) 1 The parts by weight were mixed by stirring, and further kneaded with a three-roll mill to obtain an adhesive composition. A 1% spherical silica spacer having a diameter of 5 μm was mixed with this adhesive composition to prepare a liquid crystal cell in the same manner as in Example 1. The evaluation results are as shown in Table 1.

(Comparative Example 1) As an epoxy resin, a bisphenol A type epoxy resin (made by Yuka Shell Epoxy Co., Ltd.,
Epicoat 828) 80 parts by weight, bisphenol A type epoxy resin (Okaka Shell Epoxy Co., Epicoat 10
01) 20 parts by weight, 10 parts by weight of adipic dihydrazide (manufactured by Otsuka Chemical Co., Ltd.) as a curing agent, and amorphous silica (manufactured by Nippon Aerosil Co., Ltd., Aerosil R-97) as an inorganic filler.
2) 5 parts by weight, spherical silica (Admatex, SO
-C4) 20 parts by weight, ethyl carbitol 1 as a solvent
3 parts by weight were mixed by stirring, and further kneaded with a three-roll mill to obtain an adhesive composition. This adhesive composition has a diameter of 5μ
A spherical silica spacer of m was mixed with 1%, and a liquid crystal cell was produced in the same manner as in Example 1. The evaluation results are as shown in Table 1.

(Comparative Example 2) As an epoxy resin, a bisphenol A type epoxy resin (made by Yuka Shell Epoxy Co.,
Epicoat 828) 40 parts by weight, bisphenol A type epoxy resin (Okaka Shell Epoxy Co., Epicoat 10
01) 30 parts by weight, o-cresol novolac type epoxy resin (Sumitomo Chemical Co., Ltd., ESCN-195LB) 10 parts by weight, glycidyl amine type epoxy resin (Okaka Shell Epoxy Co., Epicoat 604) 20 parts by weight, as a curing agent 15 parts by weight of dicyandiamide, amorphous silica as an inorganic filler (Aerosil R-97 manufactured by Nippon Aerosil Co., Ltd.)
2) 5 parts by weight, alumina (UA-505, Showa Denko KK)
5) 20 parts by weight and 20 parts by weight of methyl carbitol as a solvent were stirred and mixed, and further sufficiently kneaded with a three-roll to obtain an adhesive composition. A 1% spherical silica spacer having a diameter of 5 μm was mixed with this adhesive composition to prepare a liquid crystal cell in the same manner as in Example 1. The evaluation results are as shown in Table 1.

[0024]

[Table 1]

[0025]

The sealing material for a liquid crystal display device of the present invention achieves electrical neutralization by the capture of organic and inorganic ions by crown ether, and the constituted cryptate is more than the distance between the cross-linking points of the cured material of the sealing material. Since it is possible to prevent these components from eluting into the liquid crystal, it is possible to provide a liquid crystal display element having excellent display characteristics.

Claims (3)

[Claims] 1. A one-component or two-component adhesive composition containing a thermosetting resin, a curing agent and an inorganic filler as main components, wherein a macrocyclic polyether (crown ether) is an essential component. A sealant composition for a liquid crystal display device. 2. The sealing material composition for a liquid crystal display device according to claim 1, wherein the thermosetting resin is an epoxy resin. 3. A liquid crystal display device using the sealant composition for a liquid crystal display device according to claim 1.