JP2008003260A - Sealant for liquid crystal dripping methods, top-bottom conducting material, and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dripping sealant which is excellent in drawing hardly contaminating the liquid crystals and can manufacture liquid crystal display elements for high quality images with less uneven colors when manufacturing liquid crystal display elements by a dripping method, and also provide top-bottom conducting materials made by using the dripping sealant and liquid crystal display elements thereof. <P>SOLUTION: This sealant is used in the liquid crystal dripping method and contains a hardening resin and a photopolimerization initiator. It has a viscosity of 600,000 mPa s or less at 25°C when measured using an E viscometer. The hardening resin contains a partially (meta) acrylicized epoxy resin having at least two or more (meta) acrylic groups and one or more epoxy groups in the molecule. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention provides a liquid crystal dropping method sealing agent that can produce a liquid crystal display element with excellent image quality, less liquid color contamination, less color unevenness, and high quality in the production of a liquid crystal display element by a dropping method, The present invention relates to a vertical conduction material using the liquid crystal dropping method sealing agent and a liquid crystal display element.

Conventionally, a liquid crystal display element such as a liquid crystal display cell forms a cell by facing two transparent substrates with electrodes facing each other at a predetermined interval and sealing the periphery with a sealing agent made of a curable resin composition. However, it was produced by injecting liquid crystal into the cell from a liquid crystal injection port provided in a part thereof, and sealing the liquid crystal injection port with a sealing agent or a sealing agent.

In this method, first, a seal pattern provided with a liquid crystal injection port using a thermosetting sealant is formed on one of two transparent substrates with electrodes by screen printing, and prebaked at 60 to 100 ° C. Dry the solvent in the sealant. Next, alignment is performed with the two substrates facing each other with the spacers sandwiched therebetween, and hot pressing is performed at 110 to 220 ° C. for 10 to 90 minutes to adjust the gap near the seal, and then in an oven at 110 to 220 ° C. Heat for 10 to 120 minutes to fully cure the sealant. Next, liquid crystal was injected from the liquid crystal injection port, and finally, the liquid crystal injection port was sealed using a sealing agent to produce a liquid crystal display element.

However, according to this manufacturing method, the positional displacement, gap variation, decrease in adhesion between the sealing agent and the substrate, etc. occur due to thermal strain; residual solvent thermally expands to generate bubbles, resulting in cap variation and seal path. The seal curing time is long; the prebaking process is complicated; the usable time of the sealant is short due to the volatilization of the solvent; and it takes time to inject liquid crystal. In particular, in a large liquid crystal display device in recent years, it takes a very long time to inject liquid crystal.

On the other hand, a manufacturing method of a liquid crystal display element called a dripping method using a sealing agent made of a curable resin composition has been studied. In the dropping method, first, a rectangular seal pattern is formed on one of two transparent substrates with electrodes by screen printing or the like. Next, fine droplets of liquid crystal are dropped and applied to the entire surface of the transparent substrate frame in an uncured state of the sealant, and the other transparent substrate is immediately overlaid, and the sealant is irradiated with ultraviolet rays for temporary curing. Then, if necessary, it is heated at the time of liquid crystal annealing and further cured to produce a liquid crystal display element. If the substrates are bonded together under reduced pressure, a liquid crystal display element can be manufactured with extremely high efficiency. In the future, this dripping method is expected to become the mainstream of liquid crystal display manufacturing methods.

As a sealing agent for a liquid crystal dropping method used for the dropping method, an epoxy resin is generally used as a thermosetting component because high adhesiveness is obtained. However, the liquid crystal display device manufactured by the dropping method has a problem that display defects such as uneven color are likely to occur due to disordered alignment of the liquid crystal. This is because in the dropping method, the uncured sealing agent for the liquid crystal dropping method directly touches the liquid crystal in the process, and the sealing agent component elutes into the liquid crystal before the sealing agent is completely cured. It is due to that.

In order to solve such a problem, for example, Patent Document 1, Patent Document 2, and the like disclose a light and heat combined curing sealant. That is, the elution of the sealing agent component is suppressed by preliminarily curing with ultraviolet rays before the thermosetting process in which the component is most easily eluted from the sealing agent into the liquid crystal.

These light and heat combined curing sealants use (meth) acrylic resin as the photocuring component, epoxy resin as the thermosetting component, radical type photopolymerization initiator, and addition system as thermal epoxy curing agent. It is common to use a curing agent. Furthermore, in the light and heat combined curing system, a portion in which the epoxy group of the epoxy resin is modified with (meth) acrylic acid and the photocurable group is introduced into the epoxy resin in order to suppress elution of the epoxy resin that is not photocured into the liquid crystal In many cases, a method using a (meth) acrylated epoxy resin is used (see, for example, Patent Document 3).

However, even when a liquid crystal display element is manufactured by a dropping method using a sealing agent using a partial (meth) acrylated epoxy resin in which a photocuring group is introduced into such an epoxy resin, actually, In some cases, liquid crystal display elements having high-quality images with little color unevenness due to liquid crystal contamination cannot be produced.
Japanese Patent No. 3583326 Japanese Patent No. 3162179 JP 2004-37937 A

In view of the above-described situation, the present invention provides a liquid crystal dropping device that can produce a liquid crystal display device that has excellent drawing performance, hardly causes liquid crystal contamination, has little color unevenness, and has a high-quality image. It is an object to provide a sealing agent for a construction method, a vertical conduction material using the sealing agent for a liquid crystal dropping method, and a liquid crystal display element.

The present invention is a liquid crystal dropping method sealing agent containing a curable resin, a photopolymerization initiator, and a thermosetting agent, and has a viscosity at 25 ° C. measured using an E-type viscometer of 600,000 mPa · s. The curable resin is a sealant for a liquid crystal dropping method containing a partial (meth) acrylated epoxy resin having at least two (meth) acrylic groups and one or more epoxy groups in the molecule. .
The present invention is described in detail below.

As a result of intensive studies on the conventional light and heat combined curing sealant, the present inventors have found that the partial (meth) acrylated epoxy resin used in the conventional light and heat combined curing sealant is a molecule. The ratio of the (meth) acrylic epoxy resin having a (meth) acrylic group and an epoxy group of 1 inside, and the partially (meth) acrylated epoxy resin having such a structure not reacting at the time of photocuring in the production of the liquid crystal display element by the dropping method It was found that the unreacted part (meth) acrylated epoxy resin was eluted into the liquid crystal and caused liquid crystal contamination.
Moreover, the partial (meth) acrylated epoxy resin having 1 (meth) acrylic group and epoxy group in the molecule contains a large amount of raw material epoxy resin which is not (meth) acrylated due to the production method. It was found that this raw material epoxy resin was also eluted into the liquid crystal in the production of the liquid crystal display element by the dropping method, causing liquid crystal contamination. That is, a partially (meth) acrylated epoxy resin that has been conventionally used is manufactured by using a bifunctional epoxy resin as a raw material epoxy resin and partially (meth) acrylated. As shown in FIG. 1, the partially (meth) acrylated epoxy resin produced in (1) is actually an unreacted raw material epoxy resin, a full (meth) acrylated fully (meth) acrylated epoxy resin, and Partial (meth) acrylated partially (meth) acrylated epoxy resins were produced at a ratio of 1: 1: 2 (molar ratio, 50% acrylated), respectively.
Furthermore, partial (meth) acrylated epoxy resins obtained by partially (meth) acrylated polyfunctional novolak epoxy resins are also known as curable resins for light and heat curing sealants. Partially (meth) acrylated epoxy resins using bismuth actually contain a large amount of bifunctional epoxy resins as raw material epoxy resins, and the above-mentioned problems have not been solved. When a novolak resin having a low resin content was used, the viscosity was very high due to the molecular weight, and it could not be used as a sealing agent for the dropping method.

Therefore, as a result of further intensive studies, the present inventors have determined that the curable resin contained in the light and thermosetting sealant used in the dropping method has at least two (meth) acrylic groups in the molecule. In the production of a liquid crystal display element by a dripping method by containing a partial (meth) acrylated epoxy resin having one or more epoxy groups and further controlling the viscosity of the entire sealing agent within a predetermined range. The present inventors have found that a liquid crystal display device having excellent drawing properties, hardly causing liquid crystal contamination, little color unevenness, and high quality images can be manufactured, and the present invention has been completed.
Note that Patent Document 3 discloses a partially esterified epoxy acrylate obtained by esterifying an epoxy resin having at least two epoxy groups in one molecule with acrylic acid or the like. However, in fact, Patent Document 3 uses a bifunctional bisphenol A type liquid epoxy resin as a raw material epoxy resin of a partially esterified epoxy acrylate in the Examples, and a part (meta) formed using the above-mentioned bifunctional epoxy resin. ) No consideration is given to the problem of using an acrylated epoxy resin as a curable resin for a sealing agent for a liquid crystal dropping method. Further, as the curable resin, a resin containing a partial (meth) acrylated epoxy resin having at least two (meth) acrylic groups and one or more epoxy groups in the molecule is used, and the viscosity of the entire sealing agent is used. The effects of the above-described present invention obtained by controlling the value within the predetermined range are not studied at all.

The sealing agent for liquid crystal dropping method of the present invention (hereinafter also referred to as the sealing agent of the present invention) has a curable resin.
In the sealing agent of the present invention, the curable resin is a partial (meth) acrylated epoxy resin (hereinafter referred to as a portion according to the present invention) having at least two (meth) acrylic groups and one or more epoxy groups in the molecule. (Also referred to as (meth) acrylated epoxy resin). The partially (meth) acrylated epoxy resin according to the present invention has high photocurability and does not react when irradiated with light, but the residual ratio is low. Therefore, the sealing agent of the present invention in which the curable resin contains the partial (meth) acrylated epoxy resin according to the present invention is unreacted with respect to light irradiation when used for the production of a liquid crystal display element by a dropping method. Liquid crystal contamination due to the partial (meth) acrylated epoxy resin can be prevented, and a liquid crystal display element with a high quality image with little color unevenness can be produced.
In addition, in this specification, (meth) acryl means acryl or methacryl.

When the curable resin contains a compound having an epoxy group in addition to the partially (meth) acrylated epoxy resin according to the present invention, the ratio of the unreacted cured resin component to the light irradiation is low. In order to make the cured resin component of the reaction less likely to cause liquid crystal contamination, it is preferable that 50% by weight or more of the compound having an epoxy group in the curable resin is a partially (meth) acrylated epoxy resin according to the present invention, More preferably, 60% by weight or more is a partially (meth) acrylated epoxy resin according to the present invention.

The partially (meth) acrylated epoxy resin according to the present invention is obtained, for example, by reacting an epoxy group in a trifunctional or tetrafunctional epoxy resin with 2 equivalents or more and less than 4 equivalents of (meth) acrylic acid. be able to.
The epoxy group in the trifunctional epoxy resin is preferably reacted with 2 to 3 equivalents of (meth) acrylic acid. When 2 equivalents of (meth) acrylic acid is reacted with an epoxy group in a trifunctional epoxy resin, partial (meth) acrylation having 2 (meth) acrylic groups and 1 epoxy group in the molecule An epoxy resin can be obtained, and when the epoxy group in the trifunctional epoxy resin is reacted with more than 2 equivalents and less than 3 equivalents of (meth) acrylic acid, A mixture of a partially (meth) acrylated epoxy resin having one epoxy group and a resin in which all of the epoxy groups of the trifunctional epoxy resin are (meth) acrylic groups can be obtained.
The epoxy group in the tetrafunctional epoxy resin is preferably reacted with 2 to 4 equivalents of (meth) acrylic acid.

The trifunctional or tetrafunctional epoxy resin is not particularly limited, and examples thereof include triglycidyl ether of trimethylolpropane: commercially available products such as Epicron 725 (manufactured by Dainippon Ink), triglycidyl ether of tris (hydroxyphenyl) methane. : Epicoat 1032S50 (manufactured by Japan Epoxy Resin Co., Ltd.) as a commercially available product, and other commercially available products include, for example, Epicoat 630, Epicoat 604, Epicoat 1031S, Epicoat 1032H60 (all manufactured by Japan Epoxy Resin Co., Ltd.), Epicron 430, Epicron EXA7240, Epicron 5500, Epicron 5800 (all manufactured by Dainippon Ink Co., Ltd.), YH434, YH434L (all manufactured by Tohto Kasei Co., Ltd.) and the like can be mentioned.
Of these, triglycidyl ether of trimethylolpropane and triglycidyl ether of tris (hydroxyphenyl) methane are preferable because of low viscosity and excellent workability.

Specifically, the partially (meth) acrylated epoxy resin according to the present invention is, for example, 1 mol of a trifunctional epoxy resin, 2 mol of (meth) acrylic acid, triethylamine or other reaction catalyst, and a small amount of conventionally known polymerization prohibition. The agent can be produced by refluxing and stirring for several hours while feeding air.

The curable resin may contain other curable resin components other than the partially (meth) acrylated epoxy resin according to the present invention. Although it does not specifically limit as said other curable resin component, The epoxy (meth) acrylate resin more than bifunctional, ie, the epoxy resin by which all the epoxy groups were completely (meth) acrylic acid modified, is suitable.

The epoxy resin used as the raw material for the bifunctional or higher epoxy (meth) acrylate resin is not particularly limited. For example, bisphenol A type epoxy resin such as Epicoat 828EL and Epicoat 1004 (both manufactured by Japan Epoxy Resin Co., Ltd.), Epicoat 806 Bisphenol F type epoxy resin such as Epicoat 4004 (all manufactured by Japan Epoxy Resin Co., Ltd.), bisphenol S type epoxy resin such as Epicron EXA1514 (manufactured by Dainippon Ink and Co., Ltd.), RE-810NM (manufactured by Nippon Kayaku Co., Ltd.), etc. , 2'-diallylbisphenol A type epoxy resin, hydrogenated bisphenol type epoxy resin such as Epicron EXA7015 (manufactured by Dainippon Ink and Chemicals), propylene oxide-added bisphenol A type epoxy resin such as EP-4000S (manufactured by Asahi Denka), E -201 (manufactured by Nagase ChemteX) resorcinol type epoxy resin, biphenyl type epoxy resin such as Epicoat YX-4000H (manufactured by Japan Epoxy Resin), sulfide type epoxy resin such as YSLV-50TE (manufactured by Tohto Kasei Co., Ltd.), Ether type epoxy resin such as YSLV-80DE (manufactured by Toto Kasei Co., Ltd.), dicyclopentadiene type epoxy resin such as EP-4088S (manufactured by Asahi Denka Co., Ltd.), Epicron HP4032, and Epicron EXA-4700 (all manufactured by Dainippon Ink and Company) Naphthalene type epoxy resins such as, Epoxylon N-770 (manufactured by Dainippon Ink), etc., phenol novolac type epoxy resins, Epicron N-670-EXP-S (manufactured by Dainippon Ink), etc. Epicron HP7200 (Dainichi Dicyclopentadiene novolac type epoxy resin such as NC-3000P (manufactured by Nippon Kayaku Co., Ltd.), naphthalene phenol novolac type epoxy resin such as ESN-165S (manufactured by Tohto Kasei Co., Ltd.), Glycidylamine type epoxy resins such as Epicoat 630 (Japan Epoxy Resin), Epicron 430 (Dainippon Ink), TETRAD-X (Mitsubishi Gas Chemical), ZX-1542 (Toto Kasei), Epicron 726 (Manufactured by Dainippon Ink Co., Ltd.), Epolite 80MFA (manufactured by Kyoeisha Chemical Co., Ltd.), Denacol EX-611, (manufactured by Nagase ChemteX Corporation), etc., alkyl polyol type epoxy resins, YR-450, YR-207 (all of which are Toto Kasei Co., Ltd.) Rubber) such as Epolide PB (Daicel Chemical) Modified epoxy resins, glycidyl ester compounds such as Denacol EX-147 (manufactured by Nagase ChemteX), bisphenol A type episulfide resins such as Epicoat YL-7000 (manufactured by Japan Epoxy Resin), other YDC-1312, YSLV-80XY, YSLV-90CR (all manufactured by Tohto Kasei Co., Ltd.), XAC4151 (manufactured by Asahi Kasei Co., Ltd.), Epicoat 1031, Epicoat 1032 (all manufactured by Japan Epoxy Resin Co., Ltd.), EXA-7120 (manufactured by Dainippon Ink Co., Ltd.), TEPIC (Nissan Chemical Co., Ltd.) Manufactured) and the like.

Moreover, it does not specifically limit as a commercial item of the said epoxy (meth) acrylate resin more than bifunctional, For example, Evecryl 3700, Evekril 3600, Evekril 3701, Evekril 3200, Evekrill 3200, Evekrill 3600, Evekrill 3702, Evekril 3412, Evekril 860, Evekril RDX63182, Evekril 6040, Evekril 3800 (all manufactured by Daicel UC Corporation), EA-1020, EA-1010, EA-5520, EA-5323, EA-CHD, EMA-1020 (all new) Nakamura Chemical Co., Ltd.), Epoxy ester M-600A, Epoxy ester 40EM, Epoxy ester 70PA, Epoxy ester 200PA, Epoxy ester 80MFA, Epoxy Ester 3002M, Epoxy ester 3002A, Epoxy ester 1600A, Epoxy ester 3000M, Epoxy ester 3000A, Epoxy ester 200EA, Epoxy ester 400EA (all manufactured by Kyoeisha Chemical Co., Ltd.), Denacol acrylate DA-141, Denacol acrylate DA-314, Dena Examples include coal acrylate DA-911 (all manufactured by Nagase ChemteX Corporation).

The sealing agent of the present invention contains a photopolymerization initiator.
Although it does not specifically limit as said photoinitiator, What has a reactive double bond and a photoreaction start part is suitable. When such a photopolymerization initiator is used, sufficient reactivity can be imparted to the sealant of the present invention, and in the production of a liquid crystal display element by the dropping method, it is eluted into the liquid crystal and contaminates the liquid crystal. There is no. Of these, benzoin (ether) compounds having a reactive double bond and a hydroxyl group and / or a urethane bond are preferred. The benzoin (ether) compounds represent benzoins and benzoin ethers.

Examples of the reactive double bond include residues such as an allyl group, a vinyl ether group, and a (meth) acryl group, and a (meth) acryl residue is preferable because of its high reactivity. By having such a reactive double bond, the weather resistance of the sealing agent of the present invention is improved.

The said benzoin (ether) compound should just have any one of a hydroxyl group and a urethane bond, and may have both. If the benzoin (ether) compound has neither a hydroxyl group nor a urethane bond, it may elute into the liquid crystal.

In the benzoin (ether) compound, the reactive double bond and the hydroxyl group and / or the urethane bond may be located at any part of the benzoin (ether) skeleton, and are represented by the following general formula (1). Those having a molecular skeleton are preferred. If a compound having such a molecular skeleton is used as a photopolymerization initiator, the residue is reduced and the amount of outgas can be reduced.

In the formula, R represents hydrogen or a residual aliphatic hydrocarbon chain having 4 or less carbon atoms. When R is a residual aliphatic hydrocarbon chain having more than 4 carbon atoms, the storage stability when a radical photopolymerization initiator is added increases, but the reactivity may decrease due to steric hindrance of the substituent.

Examples of benzoin (ether) compounds having a molecular skeleton represented by general formula (1) include compounds represented by the following general formula (2).

In the formula, R represents hydrogen or an aliphatic hydrocarbon residue having 4 or less carbon atoms, X represents a residue of a bifunctional isocyanate derivative having 13 or less carbon atoms, and Y represents an aliphatic hydrocarbon residue having 4 or less carbon atoms. This represents a residue having an atomic ratio of carbon and oxygen constituting a group or residue of 3 or less. When X is a residue of a bifunctional isocyanate derivative having more than 13 carbon atoms, it may be easily dissolved in the liquid crystal, and Y may be an aliphatic hydrocarbon group having more than 4 carbon atoms or an atomic ratio of carbon to oxygen of 3 If the residue exceeds 50, it may be easily dissolved in the liquid crystal.

Other examples of the photopolymerization initiator include benzophenone, 2,2-diethoxyacetophenone, benzyl, benzoyl isopropyl ether, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, and thioxanthone. These photoinitiators may be used independently and may use 2 or more types together.

Although it does not specifically limit as content of the said photoinitiator, A preferable minimum is 0.1 weight part and a preferable upper limit is 10 weight part with respect to 100 weight part of said curable resins. When the amount is less than 0.1 parts by weight, the sealing agent of the present invention may not be sufficiently cured by light irradiation. When the amount exceeds 10 parts by weight, the sealing agent of the present invention is irradiated with light. The surface of the sealing agent is hardened first, the inside cannot be hardened sufficiently, and the storage stability may be lowered.

The sealing agent of the present invention contains a thermosetting agent.
It does not specifically limit as said thermosetting agent, For example, an amine compound, a polyhydric phenol type compound, an acid anhydride, etc. are mentioned.

The amine compound refers to a compound having one or more primary to tertiary amino groups in the molecule. For example, aromatic amines such as metaphenylenediamine and diaminodiphenylmethane, 2-methylimidazole, 1,2 -Imidazole compounds such as dimethylimidazole and 1-cyanoethyl-2-methylimidazole; Imidazoline compounds such as 2-methylimidazoline; Amine adducts such as techno) and dicyandiamide.

Examples of the polyhydric phenol compounds include polyphenol compounds such as EpiCure 170 and EpiCure YL6065 (both manufactured by Japan Epoxy Resin Co., Ltd.) and novolac type phenol resins such as EpiCure MP402FPI (produced by Japan Epoxy Resin Co., Ltd.).

Examples of the acid anhydride include epicure YH-306, YH-307 (both manufactured by Japan Epoxy Resin Co., Ltd.) and the like.

These thermosetting agents may be used independently and 2 or more types may be used together. Among these, it is preferable to use a dihydrazide compound in terms of excellent low-temperature curability and storage stability.

As a blending ratio of the thermosetting agent, a preferable lower limit is 1 part by weight and a preferable upper limit is 100 parts by weight with respect to 100 parts by weight of the curable resin. If the amount is less than 1 part by weight, the curable resin may be insufficiently cured. If the amount is more than 100 parts by weight, the storage stability of the sealing agent of the present invention may be deteriorated. When it becomes, there exists a possibility that moisture resistance may fall. A more preferred upper limit is 20 parts by weight.

The sealing agent of the present invention preferably further contains a silane coupling agent. The silane coupling agent mainly serves as an adhesion aid for favorably bonding the sealing agent of the present invention and the liquid crystal display element substrate.

The silane coupling agent is not particularly limited, and examples thereof include γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-isocyanatopropyltrimethoxysilane. It is done. These silane coupling agents may be used independently and 2 or more types may be used together. The γ-glycidoxypropyltrimethoxysilane is a compound having an epoxy group, but can be used within a range that does not deteriorate the display quality of a liquid crystal display device manufactured by a dropping method.

The blending ratio of the silane coupling agent is not particularly limited, but a preferable lower limit is 0.1 parts by weight and a preferable upper limit is 10 parts by weight with respect to 100 parts by weight of the curable resin. If the amount is less than 0.1 parts by weight, the performance may not be sufficiently exhibited. If the amount exceeds 10 parts by weight, the excess silane coupling agent may be eluted into the liquid crystal, thereby degrading the display quality. A more preferred lower limit is 0.5 parts by weight, and a more preferred upper limit is 3 parts by weight.

Further, the sealing agent of the present invention may contain a filler for the purpose of improving the adhesiveness due to the stress dispersion effect and improving the linear expansion coefficient.

The filler is not particularly limited, for example, talc, asbestos, silica, diatomaceous earth, smectite, bentonite, calcium carbonate, magnesium carbonate, alumina, montmorillonite, diatomaceous earth, magnesium oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, Examples include inorganic fillers such as glass beads, barium sulfate, gypsum, calcium silicate, talc, glass beads, sericite activated clay, bentonite, and organic fillers such as polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, and acrylic polymer fine particles. .

Although it does not specifically limit as a compounding ratio of the said filler, A preferable minimum is 1 weight part and a preferable upper limit is 100 weight part with respect to 100 weight part of said curable resins. If the amount is less than 1 part by weight, the performance may not be sufficiently exhibited. If the amount exceeds 100 parts by weight, handling properties such as the drawability of the sealing agent of the present invention may be deteriorated. A more preferred lower limit is 10 parts by weight, and a more preferred upper limit is 50 parts by weight.

In the sealing agent of the present invention, the upper limit of the viscosity measured at 25 ° C. using an E-type viscometer is 600,000 mPa · s. When it exceeds 600,000 mPa · s, the drawability is not sufficient, and it becomes impossible to produce a liquid crystal display element by the dropping method. A preferred lower limit is 100,000 mPa · s, and a preferred upper limit is 450,000 mPa · s.

The E-type viscometer for measuring the viscosity of the sealant of the present invention is not particularly limited, and examples thereof include “DV-III” manufactured by Brookfield.

The method for producing the sealant of the present invention is not particularly limited, and the curable resin, the photopolymerization initiator, and the thermosetting agent, and a predetermined amount of the silane coupling agent blended as necessary. The method of mixing these by a conventionally well-known method is mentioned. At this time, in order to remove the ionic impurities contained, it may be brought into contact with an ion-adsorbing solid.

Since the viscosity of the sealant of the present invention is 600,000 mPa · s or less, the drawing property is also excellent. In addition, since the curable resin contains a partial (meth) acrylated epoxy resin having two or more (meth) acrylic groups and one or more epoxy groups in the molecule, in the production of a liquid crystal display element by a dropping method, A liquid crystal display element with a high quality image can be produced without causing liquid crystal contamination.

A vertical conduction material can be produced by blending conductive fine particles with the sealant of the present invention. Such a vertical conduction material containing the sealing agent of the present invention and conductive fine particles is also one aspect of the present invention.

The conductive fine particles are not particularly limited, and metal balls, those obtained by forming a conductive metal layer on the surface of resin fine particles, and the like can be used. Among them, the one in which the conductive metal layer is formed on the surface of the resin fine particles is preferable because the conductive connection is possible without damaging the transparent substrate due to the excellent elasticity of the resin fine particles.

A liquid crystal display element using the sealing agent of the present invention and / or the vertical conduction material of the present invention is also one aspect of the present invention.

As a method for producing the liquid crystal display element of the present invention, for example, one of two transparent substrates with electrodes, such as an ITO thin film, is formed into a rectangular shape by screen printing, dispenser application, etc. of the liquid crystal dropping method sealing agent of the present invention. A step of forming a seal pattern of the present invention, a step of applying a liquid crystal micro-droplet on the entire surface of a transparent substrate in an uncured state with the liquid crystal dropping method sealing agent of the present invention uncured, and immediately overlaying the other transparent substrate And a step of irradiating the seal pattern portion of the sealant for the liquid crystal dropping method of the present invention with light such as ultraviolet rays to temporarily cure, and heating the temporarily cured seal pattern for the liquid crystal dropping method of the present invention. The method etc. which have the process of carrying out the main hardening of the seal pattern which consists of sealing agents etc. are mentioned.
Such a liquid crystal display element using the sealing agent of the present invention and / or the vertical conduction material of the present invention is also one aspect of the present invention.

According to the present invention, the curable resin contains a partial (meth) acrylated epoxy resin having at least two (meth) acrylic groups and one or more epoxy groups in the molecule, and has a viscosity of 600,000. Since it is mPa · s or less, in the production of a liquid crystal display element by a dropping method, a liquid crystal dropping method that can produce a high quality image liquid crystal display element that has excellent drawability, hardly causes liquid crystal contamination, and has little color unevenness. Sealing agent, vertical conduction material using the liquid crystal dropping method sealing agent, and a liquid crystal display element can be provided.

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

(Synthesis of partially acrylated epoxy resin (1))
405 g of Epicron 725 (Dainippon Ink Co., Ltd .: epoxy equivalent 135) was dissolved in 1000 mL of toluene, and 0.2 g of triphenylphosphine was added to the solution to obtain a uniform solution. To this solution, 144 g of acrylic acid was added dropwise over 2 hours with stirring under reflux, followed by further stirring under reflux for 8 hours.
Next, toluene was removed to obtain a partially acrylated epoxy resin (1) (Epicron 725-modified product) in which 2/3 of the epoxy groups were converted to acryloyl groups.

(Synthesis of partially acrylated epoxy resin (2))
Epicoat 1032S50 (manufactured by Japan Epoxy Resin Co., Ltd .: Epoxy equivalent 165) was dissolved in 1500 mL of toluene, and 0.2 g of triphenylphosphine was added to the solution to obtain a uniform solution. To this solution, 144 g of acrylic acid was added dropwise over 2 hours with stirring under reflux, followed by further stirring under reflux for 8 hours.
Next, toluene was removed to obtain a partially acrylated epoxy resin (2) (Epicoat 1032S50 modified product) in which 2/3 of the epoxy groups were converted to acryloyl groups.

(Examples 1-3, Comparative Examples 1-3)
Examples 1 to 3 were prepared by mixing the raw materials of the predetermined blending amounts shown in Table 1 below using a planetary stirrer (Awatori Netaro: manufactured by Shinky Corp.) and further mixing using three rolls. The sealing agents of Comparative Examples 1 to 3 were obtained.

(Evaluation)
(Production of liquid crystal display element)
The sealing agent which concerns on Examples 1-3 and Comparative Examples 1-3 was apply | coated to the board | substrate with a transparent electrode with a dispenser so that a rectangular frame might be drawn. Subsequently, a fine drop of liquid crystal (manufactured by Chisso Corporation; JC-5004LA) is dropped onto the entire surface of the transparent substrate frame, and another substrate with a transparent electrode is immediately overlaid, and UV light is applied to the seal portion using a high-pressure mercury lamp. Irradiation was performed at 100 mW / cm ² for 20 seconds. Thereafter, liquid crystal annealing was performed at 120 ° C. for 1 hour, and at the same time, the sealant was thermally cured to obtain a liquid crystal display element.

(Display unevenness evaluation)
About the obtained liquid crystal display element, the color unevenness which arises in the liquid crystal around a seal | sticker part was observed visually immediately after board | substrate preparation and after leaving for 1000 hours in 80 degreeC environment, and evaluated according to the following reference | standard.
◎: No color unevenness ○: Little color unevenness △: Some color unevenness ×: There is considerable color unevenness

According to the present invention, in the manufacture of a liquid crystal display element by a dropping method, a seal for a liquid crystal dropping method, which is excellent in drawability, hardly causes liquid crystal contamination, and can produce a liquid crystal display element having a high quality image with little color unevenness. Agent, a vertical conduction material using the sealing agent for liquid crystal dropping method, and a liquid crystal display element can be provided.

It is the figure which showed the component and ratio of the conventional partial (meth) acrylated epoxy resin manufactured by carrying out partial (meth) acrylation of the bifunctional epoxy resin.

Claims (6)

A sealing agent for a liquid crystal dropping method containing a curable resin, a photopolymerization initiator, and a thermosetting agent, the viscosity at 25 ° C. measured using an E-type viscometer is 600,000 mPa · s or less, The said curable resin contains the partial (meth) acrylated epoxy resin which has at least 2 or more (meth) acryl group and 1 or more epoxy group in a molecule | numerator, The sealing compound for liquid crystal dropping methods characterized by the above-mentioned. 50% by weight or more of the epoxy group-containing compound in the curable resin is a partially (meth) acrylated epoxy resin having at least two (meth) acrylic groups and one or more epoxy groups in the molecule. The sealing agent for liquid crystal dropping method according to claim 1. The partial (meth) acrylated epoxy resin having at least two (meth) acrylic groups and one or more epoxy groups in the molecule is 2 equivalents or more to the epoxy group in the trifunctional or tetrafunctional epoxy resin. The sealing agent for liquid crystal dropping method according to claim 1 or 2, which is a partially (meth) acrylated epoxy resin obtained by reacting less than an equivalent amount of (meth) acrylic acid. The sealing agent for liquid crystal dropping method according to claim 3, wherein the trifunctional or tetrafunctional epoxy resin is triglycidyl ether of trimethylolpropane or triglycidyl ether of tris (hydroxyphenyl) methane. A vertical conduction material comprising the sealing agent for liquid crystal dropping method according to claim 1, 2, 3, or 4, and conductive fine particles. A liquid crystal display element comprising the sealing agent for liquid crystal dropping method according to claim 1, 2, 3 or 4, and / or the vertical conduction material according to claim 5.

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