JP2000072955A - Low-temperature-curing or high-temperature short-time- curing liquid crystal seal material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition being nonproblematic in the unevenness of the display of a liquid crystal cell, having excellent adhesiveness and storage stability and good productivity, and being capable of giving a high-grade liquid crystal cell by selecting a composition essentially consisting of an epoxy resin, a rubber, a filler, a curing agent, and a reactive diluent. SOLUTION: The epoxy resin used is, for example, a bisphenol-derived one and has a number-average molecular weight of at most 7,000. The rubber is, for example, an acrylic ester type one and has a particle diameter of 0.01-5 μm. The filler used is, for example, calcium carbonate. The amounts of use per 100 pts.wt. composition are 20-50 pts.wt., 1-15, pts.wt., and 1-50 pts.wt. for the epoxy resin, the rubber, and the filler, respectively. The curing agent is one reactive with the epoxy resin, e.g. an aliphatic amine and is used in an amount of 1-60 pts.wt. per 100 pts.wt. epoxy resin. The reactive diluent is one having at least one epoxy group in the molecule and having a viscosity of 500 Pa.s or below (e.g. Ed-505) and is used in an amount of 1-70 wt.% based on the seal material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component, low-temperature-curable or high-temperature, short-time-curable liquid crystal sealing material composition for use in sealing liquid crystal display cells, which is solvent-free and has a long pot life. is there.

[0002]

2. Description of the Related Art In recent years, liquid crystal displays having the characteristics of light weight and thinness have been widely used as display devices for various devices including personal computers. The usage environment for automobiles and industrial use is becoming severer. Recently, liquid crystal cells have been increased in size, and accordingly, improvement in productivity and higher quality of products have been required. By the way, a liquid crystal display element is one in which liquid crystal is sealed between transparent glass or a plastic substrate,
The liquid crystal is used by driving it at a low voltage. At this time, a liquid crystal sealing material is used to seal the liquid crystal so as not to leak to the outside of the substrate to form a cell.

[0003] Currently used liquid crystal sealing materials are mainly of a one-liquid type and a two-liquid type, and as a currently used one-liquid type sealing material, those which usually contain a solvent are mainly used. I have. However, the one-pack type sealing material usually used has a disadvantage that it takes a long time to cure. Therefore, as a material that can be cured in a short period of time, there is a UV-curable sealing material, but the reliability is not sufficient and the sealing material has not been used for a large-sized liquid crystal cell. Further, Japanese Patent Publication No. 58-22060 describes a non-solvent type sealing material.However, since a liquid butadiene-acrylonitrile copolymer or a polyester ether elastomer is mainly used, the crosslinking density is poor. Heat resistance and moisture resistance are not enough.

Japanese Patent Application Laid-Open No. 7-26236 discloses an example in which an inorganic filler and a silane coupling agent are used. However, the inorganic filler cannot sufficiently reduce internal stress caused by curing. Further, even if the adhesion to glass is obtained by the silane coupling agent, the cell has a transparent electrode, an alignment film, and the like, and the adhesion to these can not be expected at all.
Further, even though the solvent volatilization step is unnecessary, the main curing requires about 1 hour at 150 ° C. due to the composition, and a significant improvement in productivity cannot be expected at all. Also, JP-A-6-7523
No. 1 discloses the use of rubber, which also contains a solvent. Therefore, pre-baking is carried out at 90 ° C. for 20 minutes to evaporate the solvent, and the curing temperature is 150 ° C. × 60. It must be minutes, hot and long.

[0005]

Accordingly, these materials are difficult to cope with the severe use environment in recent years, and high quality and high productivity cannot be obtained with the shift to large cells.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and have found that epoxy resin, rubber,
The present inventors have found that a solvent-free sealing material composition using a filler, a curing agent, and a reactive diluent has excellent sealing performance and cures at a low temperature or at a high temperature for a short time, thereby completing the present invention. That is, the present invention provides the following (1) to (6).

(1) A liquid crystal sealing material composition comprising an epoxy resin, a rubber, a filler, a curing agent, and a reactive diluent as essential components.

(2) A liquid crystal sealing material composition containing an epoxy resin, a rubber, a filler, a curing agent, and a reactive diluent as essential components and containing no organic solvent.

(3) The epoxy resin has at least one epoxy group in one molecule and has a molecular weight of 7
(1) or (2).
The liquid crystal sealing material composition according to the above.

(4) The rubber is present in a state of being dispersed as particles in an epoxy resin.
The liquid crystal sealing material composition according to any one of (1) to (3).

(5) The reactive diluent has at least one epoxy group in one molecule and has a viscosity of 500 mPa · S
The liquid crystal sealing material composition according to any one of (1) to (4), which is:

(6) A liquid crystal sealing material comprising the liquid crystal sealing composition according to any one of (1) to (5).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Liquid crystal sealing material composition of the present invention, epoxy resin,
It contains rubber, a curing agent, and a reactive diluent as essential components. The epoxy resin used in the present invention is 1
There is no particular limitation as long as it has one or more epoxy groups in the molecule, and any of liquid and solid at room temperature can be used.

Examples of the epoxy resin include, for example, group (A); (1) bisphenol A, bisphenol F, bisphenol AD, (2) a novolak resin obtained by addition polymerization of phenol or cresol and formaldehyde, and tetrahydroxyphenyl methane. And hydroxy compounds such as resorcinol; (3) amine compounds such as diaminodiphenylmethane, aniline and xylylenediamine; polyhydric alcohols such as glycerin and pentaerythritol; or carboxy compounds such as phthalic acid and hexahydrophthalic acid; and epichlorohydrin. , A polycondensation resin with epihalohydrin such as epibromohydrin, and methyl epihalohydrin such as methyl epichlorohydrin, and a resin obtained by halogenating the polycondensation resin; Epoxidized fatty acids such as oils and derivatives thereof, (C) group; epoxidized diene polymers such as epoxidized polybutadiene and epoxidized polyisoprene, or (D) group; 3,4-epoxy-6-methylcyclohexylmethyl Aliphatic epoxy resins such as -3,4-epoxy-6-methylcyclohexane carbonate and bis (2,3-epoxycyclopentyl) ether;
One or more of these can be used. Of these, particularly preferred are the compounds of the group (A).

The amount of the epoxy resin used in the present invention is preferably 20 to 5 per 100 parts by weight of the sealing material composition.
It is preferable to contain it in the range of 0 parts by weight.

The number average molecular weight of the epoxy resin used in the present invention is not particularly limited, but is usually 7000 or less, preferably 2,000 or less. When an epoxy resin having a number average molecular weight exceeding 2000 is used, it is necessary to add a relatively large amount of a reactive diluent in order to reduce the sealing agent to an appropriate viscosity. If the amount of the reactive diluent used is not excessively large, there is no influence such as a decrease in crosslink density, spots, a decrease in Tg, a decrease in the reaction rate, and the like, which is suitable for producing a high-quality cell.

As the rubber used in the present invention, rubber particles may or may not be grafted with the epoxy resin as long as the rubber particles are dispersed in the epoxy resin. Examples of the rubber include an acrylic ester type, a silicon type, a conjugated diene type, an olefin type, a polyester type, and a urethane type. These may be used alone or in combination of two or more. As a method of dispersing rubber particles, there are a method of simply dispersing rubber in an epoxy resin and a method of grafting. Preferably, a method of forming rubber particles in the presence of a graft copolymer with an epoxy resin and a graft copolymer with an epoxy resin is preferred. More preferably, the rubber particles are crosslinked. Hereinafter, a more specific description will be given.

As the acrylic ester rubber, a core /
Examples include a method using rubber particles obtained by drying a shell emulsion, and those disclosed in JP-A-55-16053 or JP-A-55-21432. The latter is preferred from the viewpoint of the viscosity later.

As the silicone rubber, a method using silicon rubber fine particles, a method disclosed in JP-A-60-72957, a method disclosed in JP-A-3-170523, and a method in which epoxy resin is used A method in which a bond is introduced and hydrogen-containing silicon capable of reacting with the double bond is reacted to form a graft, and a silicone rubber monomer is polymerized in the presence of the graft to introduce a double bond into an epoxy resin. Then, a method of reacting the polymer with a vinyl group-containing silicone rubber monomer to form a graft, a method of polymerizing the silicone rubber monomer in the presence of the graft, and the like are available. Preferably, a method of producing rubber particles after producing a graft and a graft without using silicon rubber fine particles is preferable. In these methods, the produced rubber particles are easily controlled, and a viscosity increase after dispersion is small and the sealing material is small. This gives good results in printability.

As the conjugated diene rubber, for example, 1,
3-butadiene, 1,3-pentadiene, isoprene,
It can be produced by polymerizing or copolymerizing monomers such as 1,3-hexadiene and chloroprene, and commercially available products can be used. For example, a copolymer of butadiene having a carboxyl group at a terminal and acrylonitrile, a copolymer of butadiene having an amino group at a terminal and acrylonitrile, and the like can be given.

The rubber used in the present invention has a particle diameter of 0.1.
Rubber having a size of from 01 to 5 μm, preferably from 0.01 to 2 μm is good. When the particle diameter is other than the above, it tends to be difficult to control the gap between the cell substrates. The amount of rubber used is as follows: 1. 100 parts by weight of the sealing material composition as rubber.
0 to 15 parts by weight is preferred. More preferably 2.0 to
10.0 parts by weight. When the amount is less than 1.0 part by weight, the stress relaxation is not sufficient, and the adhesion to the cell may be inferior. In the case where the amount is more than 15 parts by weight, the stress relaxation is sufficient, but the sealing material composition is high. As a result, a large amount of the reactive diluent must be used, and the sealing performance and the like tend to decrease. One or more of these rubbers can be used.

As the filler used in the present invention, specifically, for example, 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, asbestos powder, quartz powder, mica,
Inorganic filler such as glass fiber, polyethylene powder, polypropylene powder, polyester powder, polyvinyl chloride powder, polystyrene powder, polyvinyl acetate powder, polyethylene-vinyl acetate copolymer powder, polymethacrylate powder, polyurethane powder, urea resin powder And organic fillers such as phenol resin powder, benzoguanamine resin powder and epoxy resin powder. One or more of these fillers can be used.

The amount of these fillers to be added is preferably 1 to 50 parts by weight, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the sealing material composition. When the distance between the bases constituting the cell is as narrow as 1 to 3 μm, it may not be necessary to use a filler.

The curing agent used in the present invention is not particularly limited in Japanese Patent Application Laid-Open No. SHOKO, as long as it can react with the epoxy resin, and any of them can be used. In particular,
For example, amines such as aliphatic amines, aromatic amines, modified amines, and polyamines, organic acids, aromatic acid anhydrides, cyclic aliphatic acid anhydrides, aliphatic acid anhydrides, halogenated acid anhydrides, and modified acid anhydrides Acid anhydride, polyamide resin, polyamide resin such as polyamide adduct, imidazoles and derivatives thereof, boron trifluoride-amine complex, dicyandiamide and derivatives thereof, organic dihydrazide compound, diaminomaleonitrile and derivatives thereof, melamine and derivatives thereof , Polymercaptans, and the like. One or more of these can be used. A curing accelerator may be used in combination with these curing agents.

The amount of the curing agent to be added is, in the case of an equivalent ratio, epoxy group / curing agent functional group = 1.00 / 0.15 to 1.0
0 / 1.50 is preferable, and 1.00 / 0 is more preferable.
0.15 to 1.00 / 1.00. In the case of parts by weight, 1 to 6 parts per 100 parts by weight of the resin having an epoxy group is used.
0 parts by weight is preferred.

The reactive diluent used in the present invention is:
Having at least one epoxy group in the molecule and having a viscosity of 500 mP
Those having a · S / 25 ° C. or lower are preferred. Specifically, for example, as a commercial product, ED-5
05, ED-506, ED-509 (all of which are trade names,
Asahi Denka Kogyo Co., Ltd.), HELOXY8, HELOX
Y116, HELOXY69, HELOXY5048
(All of which are trade names, manufactured by AC I Japan Limited). The amount to be added may be an amount for obtaining a desired viscosity of the sealing material, but is preferably contained in the sealing material composition at 1 to 70% by weight.
More preferably, it is 5 to 40% by weight. If it is less than 1% by weight, the dilution effect tends to be poor, and if it exceeds 70% by weight, a highly reliable sealing material composition tends to be hardly obtained. In addition, when a reactive diluent having no epoxy group is used, although it has a diluting effect, it is not involved in the reaction, so it may be affected by volatilization at the time of curing, such as contamination in the cell, reduction of Tg, and inhibition of the reaction. May be less preferred. If the viscosity exceeds 500 mPa · S, a large amount of reactive diluent will be used to adjust the viscosity of the sealing material composition, and the original sealing material composition balance will be lost, and a highly reliable sealing material will be produced. It tends to be difficult to obtain.

In the liquid crystal sealing material composition of the present invention,
It is not necessary to use an organic solvent in the composition, and one of the preferable embodiments is to provide a solventless sealing material composition. By not using an organic solvent, etc., there is no need to perform pre-curing for solvent evaporation, and each step of solvent volatilization and pre-curing is not required, which simplifies the process, leading to cost reduction and economical It is also excellent. Further, since no solvent is used, no contamination in the cell or the like occurs.

In the present invention, if necessary, a coupling agent, a spacer, a leveling agent, a pigment, a dye, a plasticizer, a defoaming agent, a solvent, a thickener, and a thixotropic agent can be used. Further, the composition of the present invention is excellent in curability, adhesiveness and reliability, and can be used as an adhesive for glass, plastics, metals, and inorganic substances in addition to the liquid crystal sealing material.

[0029]

Hereinafter, the present invention will be described in detail with reference to typical examples, but the present invention is not limited to these examples.

[Synthesis of Rubber] Synthesis Example 1 2000 equipped with a stirrer, gas introduction pipe, thermometer and cooling pipe
600 g of bisphenol F-type epoxy resin (trade name: Epicron 830S, manufactured by Dainippon Ink and Chemicals, Inc.), 12 g of acrylic acid, 1 g of dimethylethanolamine and 50 g of toluene were added to a four-necked four-neck flask.
The reaction was carried out at 110 ° C. for 5 hours while introducing air to introduce a double bond. Next, 350 g of butyl acrylate, 20 g of glycidyl methacrylate, divinylbenzene
1 g of azobisdimethylvaleronitrile and 2 g of azobisisobutyronitrile were added, and the mixture was reacted at 70 ° C. for 3 hours while introducing nitrogen into the reaction system.
For 1 hour. Subsequently, toluene was removed under reduced pressure at 110 ° C. to obtain a graft polymer of an epoxy resin and an acrylic ester in which an acrylic rubber was dispersed. This polymer (A) has an average particle size of 0.05 μm and a rubber content of
37.9%.

Synthesis Example 2 Synthesis was performed in the same manner as in Synthesis Example 1. First, a double bond was introduced, and then 5 g of hydroxy acrylate, 10 g of butyl acrylate and 1 g of azobisisobutyronitrile were added, reacted at 70 ° C. for 3 hours, and further reacted at 90 ° C. for 1 hour. Then, toluene was removed under reduced pressure at 110 ° C.
Next, a silicon intermediate having a methoxy group in the molecule 70
g, 0.3 g of dibutyltin dilaurate, and 15
The reaction was performed at 0 ° C. for 1 hour, and the reaction was continued for another 1 hour to remove generated methanol. To the thus obtained graft, 300 g of a mixture of a room temperature-curable two-pack type silicone rubber at 1/1 was added, and the mixture was reacted for 2 hours to obtain a graft in which the silicone rubber was dispersed. This polymer (B) had an average particle size of 1.5 μm and a rubber content of 30.
It was 0%.

Synthesis Example 3 Synthesis was performed in the same manner as in Synthesis Example 1. First, a double bond was introduced, then 50 g of radical-reactive silicon oil and 1 g of azobisisobutyronitrile were added, reacted at 70 ° C. for 3 hours, and further reacted at 90 ° C. for 1 hour. Then 110
Detoluene was performed under reduced pressure at ℃. In the same manner as in Synthesis Example 2, a room temperature-curable two-pack type silicone rubber was mixed and reacted to obtain a graft in which the silicone rubber was dispersed. This polymer (C) has an average particle size of 0.5 μm and a rubber content of
31.1%.

Examples 1 to 10 and Comparative Examples 1 to 3 The blends as described in the formulations in Tables 1 to 3 were premixed with a Dalton mixer, and the solid material was reduced to 5 μm or less with three rolls. Until kneaded. When a solid epoxy resin was used, it was used after being dissolved by heating with a reactive diluent.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[Explanation of symbols] Epoxy resin A: EPICLON 830 (trade name, the same applies hereinafter), epoxy resin B manufactured by Dainippon Ink and Chemicals, Inc. B: YDCN-701, reactive diluent A manufactured by Toto Kasei Co., Ltd .: ED-506 ・ Epoxy group 2.60m
Pa · S, manufactured by Asahi Denka Kogyo Co., Ltd. (each represents a trade name / number of epoxy groups / viscosity, the same applies hereinafter) Reactive diluent B: ED-509 / epoxy group 1.30 m
Pa · S, manufactured by Asahi Denka Kogyo Co., Ltd. Reactive diluent C: ED-508 / epoxy group 0.30 m
Pa · S, Asahi Denka Kogyo Co., Ltd. Hardener A: FXR-1030. , Fuji Kasei Kogyo Co., Ltd. Hardener B: CatZ-15 Mitsui Chemicals Co., Ltd. Silane coupling agent: KBM-403 Shin-Etsu Chemical Co., Ltd.

The sealing material composition adjusted by the above-mentioned composition was degassed in a vacuum, and a 5 μm spacer was sufficiently mixed for evaluation. First, a pattern is screen-printed on a transparent electrode and an alignment film-treated glass substrate, another glass substrate is bonded, and pressed with a compression jig.
Heated to 120 ° C or 150 ° C as needed. Of the above patterns, the bonding area is 10 mm × 10
mm was subjected to an adhesion test. 1 with 1 mm seal width
For the inch-size panel, ester-type liquid crystal is sealed from the liquid crystal filling port, and the filling port is structured bond ES-302.
(Trade name, manufactured by Mitsui Chemicals, Inc.) to produce a liquid crystal panel.

The obtained low-temperature curing type and / or high-temperature short-time curing type liquid crystal sealing material composition, test piece and liquid crystal panel were evaluated by the following methods and are shown in Tables 4 to 7.

1. Storage stability: Liquid crystal sealing material composition 10
0 g was placed in a polyethylene container and sealed, and stored at 20 ° C. for 7 days and at −15 ° C. for 6 months. The viscosity was measured with an EH type viscometer, and the viscosity magnification relative to the initial viscosity was measured.

2. Display characteristics: 20 liquid crystal panels at 80 ° C
After aging for 00 hours, a polarizing plate was applied thereto, and the display state after voltage application was visually observed or observed with an optical microscope to evaluate. The contents of the evaluation symbol are as follows.

A: No problem. : A domain was observed within a range of 10 μm or less, as confirmed by a microscope (100 × magnification). Δ: Confirmed with a microscope (magnification: 50 times), and there is a domain within a range of 100 μm or less. ×: display unevenness can be visually confirmed.

3. Adhesion test: After performing a pressure cooker test (120 ° C., 2 kg / cm ² G) on the test piece for 50 hours, the adhesion was measured with a cutter. The contents of the evaluation symbol are as follows.

: No problem (crack on glass substrate) △: Partial peeling ×: Full peeling

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Table 6]

[0048]

[Table 7]

[0049]

The liquid crystal sealing composition of the present invention can be cured at a low temperature or at a high temperature for a short time, and the cell using this sealing material has display unevenness. In addition, excellent adhesive strength, excellent storage stability of the sealing material composition, good productivity, and high-quality cells can be obtained.

 ────────────────────────────────────────────────── ─── Continued on the front page F-term (reference) 2H089 MA04Y MA05Y QA12 QA16 4J002 AC022 AC032 AC092 BB033 BC003 BG042 CD004 CD011 CD021 CD041 CD051 CD061 CD101 CD131 CD161 CD181 CF003 CP032 DE106 DE116 DE136 DE146 DE186 DE236 DJ0 DG006 DG 006 EL137 EN017 EN057 ER027 EU117 FD013 FD016 FD147 FD204 FD208 GJ02

Claims (6)

[Claims] 1. An epoxy resin, rubber, filler, curing agent,
A liquid crystal sealing material composition comprising a reactive diluent as an essential component. 2. An epoxy resin, rubber, filler, curing agent,
A liquid crystal sealing material composition comprising a reactive diluent as an essential component and no organic solvent. 3. The epoxy resin has at least one epoxy group in one molecule and has a molecular weight of 7000.
The liquid crystal sealing material composition according to claim 1 or 2, wherein: 4. The rubber according to claim 1, wherein said rubber is present in a dispersed state as particles in an epoxy resin.
The liquid crystal sealing material composition according to any one of the above. 5. The reactive diluent according to claim 1, wherein the reactive diluent has at least one epoxy group in one molecule, and has a viscosity of 500 mPa · S or less. Liquid crystal sealing material composition. 6. A liquid crystal sealing material comprising the liquid crystal sealing agent composition according to claim 1.