JP2006030481A - Sealing material for liquid crystal display element, vertically conducting material, and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing material for a liquid crystal display element, which is besy suitable for manufacture of the liquid crystal display element by a dispenser method particular since even a section not directly irradiated with light can be sufficiently cured and color irregularity ias hardly caused in the liquid crystal display because that its component does nt dissolve into the liquid crystal to contaminate the liquid crystal in the manufacture of the liquid crystal display element, and to provide a vertically conducting material and the liquid crystal display element. <P>SOLUTION: The sealing agent for the liquid crystal display element contains a photocuring resin, a photo-radical polymerization initiator and a radical chain transfer agent, wherein 0.001-1 pts.wt. of the radical chain transfer agent is included in the sealing agent with respect to 100 pts.wt. of the photocuring resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention is particularly suitable for the production of liquid crystal display elements by the dripping method because the components do not dissolve in the liquid crystal and cause liquid crystal contamination in the production of the liquid crystal display elements, and there is little color unevenness in the liquid crystal display. The present invention relates to a liquid crystal display element sealing agent, a vertical conduction material, 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 in which a liquid crystal injection port using a thermosetting sealant is provided by screen printing on either one of two transparent substrates with electrodes is formed at 60 to 100 ° C.
Pre-bake to dry the solvent in the sealant. Next, alignment is performed with the two substrates facing each other with a spacer interposed therebetween, and the gap in the vicinity of the seal is adjusted by performing hot pressing at 110 to 220 ° C. for 10 to 90 minutes, and then at 110 to 220 ° C. in an oven. 10
Heat for ~ 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 display element used for such a dripping method, for example, in Patent Document 1,
A photothermosetting sealant is disclosed that is photocured with radicals generated by irradiating ultraviolet rays, and further thermally cured with a contained thermosetting agent.
However, in recent years, with the progress of the narrowing of the frame of the liquid crystal panel, the sealing agent pattern for the liquid crystal display element formed on the transparent substrate is often positioned to overlap with the black matrix (BM) and the wiring. As described above, the sealant in the portion overlapping with the BM and the wiring has a problem that an uncured portion is formed in the sealant because it is not directly irradiated with ultraviolet rays when performing temporary curing.

When manufacturing a liquid crystal display element by the dropping method, if there is a portion that is not cured by ultraviolet irradiation in the sealing agent for liquid crystal display element, (1) heat curing takes a long time and the components in the sealing agent are liquid crystal by heating. (2) Causes dripping and poor gap accuracy between substrates, and (3) Locations with no adhesiveness after photocuring exist. There was a problem that occurred.

JP 2001-133794 A

In view of the above situation, the present invention can sufficiently cure even a portion that is not directly irradiated with light in the manufacture of a liquid crystal display element, and its components dissolve into the liquid crystal and cause liquid crystal contamination. Therefore, the present invention has an object to provide a liquid crystal display element sealant, a vertical conduction material, and a liquid crystal display element that are particularly suitable for manufacturing a liquid crystal display element by a dropping method.

The present invention is a sealant for a liquid crystal display element containing a photocurable resin, a photoradical polymerization initiator, and a radical chain transfer agent, wherein the radical chain transfer agent is added to 100 parts by weight of the photocurable resin. It is a sealing agent for liquid crystal display elements containing 0.001-1 weight part.
The present invention is described in detail below.

The sealing agent for liquid crystal display elements of the present invention (hereinafter also simply referred to as the sealing agent of the present invention) contains a photocurable resin, a photoradical polymerization initiator, and a radical chain transfer agent.

In the sealing agent of the present invention, the photocurable resin refers to a resin having an unsaturated double bond capable of radical polymerization by light. Examples of such a photocurable resin include styrene derivatives, ethylene derivatives, maleimide derivatives, (meth) acrylic acid derivatives, and the like. Among them, polymerization or crosslinking can be quickly performed with active radicals generated by ultraviolet irradiation. From the point of progress, a (meth) acrylic acid derivative is preferred. In addition, in this specification, (meth) acrylic acid means acrylic acid or methacrylic acid.

As the (meth) acrylic acid derivative, urethane (meth) acrylate having a urethane bond, epoxy (meth) modified with a compound having a glycidyl group with (meth) acrylic acid
Examples thereof include compounds obtained by modifying a compound having an acrylate or a hydroxyl group with (meth) acrylic acid.

Examples of the urethane (meth) acrylate include a derivative of a diisocyanate such as isophorone diisocyanate and a reactive compound that undergoes an addition reaction with an isocyanate such as acrylic acid or hydroxyethyl acrylate. These derivatives may be chain-extended with caprolactone or polyol. Moreover, as a commercial item, "U-122P", for example,
“U-340P”, “U-4HA”, “U-1084A” (all manufactured by Shin-Nakamura Chemical Co., Ltd.), “KRM7595”, “KRM7610”, “KRM7619” (all Daicel
And UCB Co., Ltd.).

Examples of the epoxy (meth) acrylate include resorcinol type epoxy resin,
Examples thereof include epoxy (meth) acrylates derived from epoxy resins such as bisphenol A type epoxy resin and propylene glycol diglycidyl ether, and (meth) acrylic acid. Moreover, as a commercial item, "EA-1020", "EA-6320", for example
, “EA-5520” (all made by Shin-Nakamura Chemical Co., Ltd.), “Epoxy ester 70PA”,
“Epoxy ester 3002A” (all manufactured by Kyoeisha Chemical Co., Ltd.) and the like.

As the photocurable resin, a resin having a functional group capable of radical polymerization by light and a functional group capable of thermosetting may be used. Such a resin can be cured by light irradiation or heating, and can be suitably used for the dropping method. As such resin,
For example, a resin having one or more epoxy groups and (meth) acryl groups in one molecule can be given.
The resin having one or more epoxy groups and one or more (meth) acryl groups in each molecule is not particularly limited. For example, a partial (meth) acrylate of an epoxy resin, a urethane-modified (
And (meth) acrylic epoxy resin.

The partial (meth) acrylated product of the epoxy resin can be obtained, for example, by reacting an epoxy resin and (meth) acrylic acid in the presence of a basic catalyst according to a conventional method.
Examples of the epoxy resin that can be used for the partial (meth) acrylate of the epoxy resin include novolak types such as phenol novolak type, cresol novolak type, biphenyl novolak type, trisphenol novolak type, and dicyclopentadiene novolak type; bisphenol Examples include A type, bisphenol F type, 2,2′-diallyl bisphenol A type, hydrogenated bisphenol type, and polyoxypropylene bisphenol A type.

Among the compounds in which the compound having a hydroxyl group is modified with (meth) acrylic acid, examples of monofunctional compounds include 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. , 2-hydroxybutyl (
(Meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (
(Meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, methoxyethylene glycol (meth) acrylate, 2-ethoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, Benzyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, 2,2,2, -Trifluoroethyl (meth) acrylate, 2,2,3,3, -tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H, -O Tafluoropentyl (meth) acrylate, imide (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isononyl (meth) acrylate, isomyristyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate , Bicyclopentenyl (meth) acrylate, isodecyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, 2- (meth) acryloyloxye Rukohaku acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl 2
Examples thereof include hydroxypropyl phthalate, glycidyl (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate and the like.

Further, among the compounds in which the compound having a hydroxyl group is modified with (meth) acrylic acid, examples of the bifunctional compound include 1,4-butanediol di (meth) acrylate and 1,3-butanediol di (meth). ) Acrylate, 1,6-hexanediol di (meth) acrylate, 1,9 nonanediol di (meth) acrylate, 1,10 decanediol di (meth)
Acrylate 2-n-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol (meth) acrylate, ethylene glycol Di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene oxide-added bisphenol A di (meth) acrylate, ethylene oxide-added bisphenol A di (meth) acrylate , Ethylene oxide-added bisphenol F di (meth) acrylate, dimethylol dicyclopentadiene di (meth) acrylate, 1,3-butylene Cold di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide-modified isocyanuric acid di (meth) acrylate, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, carbonate diol di (meth) acrylate , Polyether diol di (meth) acrylate, polyester diol di (meth) acrylate, polycaprolactone diol di (meth) acrylate, polybutadiene diol di (meth) acrylate, and the like.

Further, among the compounds in which the compound having a hydroxyl group is modified with (meth) acrylic acid, trifunctional or higher functional compounds include, for example, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and propylene oxide addition. Trimethylolpropane tri (meth) acrylate, ethylene oxide-added trimethylolpropane tri (
(Meth) acrylate, caprolactone-modified trimethylolpropane tri (meth) acrylate, ethylene oxide-added isocyanuric acid tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane tetra (meth) Examples include acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, propylene oxide-added glycerin tri (meth) acrylate, and tris (meth) acryloyloxyethyl phosphate.

An epoxy resin having a desired acrylate ratio can be obtained by appropriately changing the blending amount of the epoxy resin and (meth) acrylic acid. Preferably, the lower limit of the carboxylic acid is 0.1 equivalent and the upper limit is 0.5 equivalent with respect to 1 equivalent of the epoxy group, more preferably the lower limit is 0.2 equivalent and the upper limit is 0.00. 4 equivalents.

The urethane-modified (meth) acrylic epoxy resin is obtained by the following method, for example. That is, a polyol is reacted with a bifunctional or higher functional isocyanate, and the remaining isocyanate group is further reacted with a (meth) acryl monomer having a hydroxyl group and glycidol. Alternatively, a polyol is not used and a bifunctional or higher isocyanate has a hydroxyl group (
You may make a meth) acryl monomer and glycidol react. Furthermore, it can be obtained by reacting glycidol with a (meth) acrylate monomer having an isocyanate group. Specifically, for example, first, 1 mol of trimethylolpropane and 3 mol of isophorone diisocyanate are reacted under a tin-based catalyst. An isocyanate group remaining in the obtained compound;
It can be obtained by reacting hydroxyethyl acrylate, which is an acrylic monomer having a hydroxyl group, and glycidol, which is an epoxy having a hydroxyl group.

It does not specifically limit as said polyol, For example, ethylene glycol, glycerol, sorbitol, a trimethylol propane, (poly) propylene glycol etc. are mentioned.

The isocyanate is not particularly limited as long as it is bifunctional or higher. For example, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4 ′ -Diisocyanate (MDI), hydrogenated MDI, polymeric MDI,
1,5-naphthalene diisocyanate, norbornane diisocyanate, tolidine diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanatephenyl) thiophosphate, tetramethylxylene diisocyanate, 1 6,10-undecane triisocyanate and the like.

The (meth) acrylic monomer having a hydroxyl group is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. Monohydric alcohol (
(Meth) acrylates; mono (meth) acrylates or di (meth) acrylates of trivalent alcohols such as trimethylolethane, trimethylolpropane, and glycerin; and epoxy acrylates such as bisphenol A-modified epoxy acrylate. These may be used alone or in combination of two or more.

The sealing agent of the present invention may contain a curable resin that can be thermally cured in addition to the photocurable resin for the purpose of improving the adhesive strength. As said thermosetting curable resin, the resin which has an epoxy group, the resin which has an isocyanate group etc. are mentioned, for example.

The resin having an epoxy group is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type resin, cresol novolac type resin, biphenyl type epoxy resin, naphthalene type epoxy resin, catechol type epoxy Examples thereof include resins.

The radical photopolymerization initiator is not particularly limited as long as it generates radicals by the energy of light and causes the polymerization reaction of the photocurable resin to proceed. For example, acetophenone compound, benzophenone compound, benzoin compound, benzoin ether Examples thereof include compounds that generate radicals when irradiated with ultraviolet rays, such as compounds, acylphosphine oxide compounds, and thioxanthone compounds. Among these compounds that are commercially available, for example,
"IRGACURE 184", "IRGACURE 369", "IRGACURE
651 ”,“ IRGACURE 907 ”,“ IRGACURE 819 ”,“ IRGA
"CURE 2959", "DAROCURE 1173" (all manufactured by Ciba Specialty Chemicals), "KAYACURE BP", "KAYACURE DETX"
-S "(both manufactured by Nippon Kayaku)," ESACURE KIP 150 "(Lamber)
ti), “S-121” (manufactured by Shinko Giken Co., Ltd.), “Sequel BEE” (manufactured by Seiko Chemical Co., Ltd.), “Solbastron BIPE”, “Solbastron BIBE” (all manufactured by Kurokin Kasei) . These photoinitiators may be used independently and 2 or more types may be used together.

The blending amount of the photo radical polymerization initiator is not particularly limited, but the photo curable resin 10
A preferable lower limit with respect to 0 part by weight is 0.5 part by weight, and a preferable upper limit is 15 parts by weight. 0.
If it is less than 5 parts by weight, curing of the sealing agent of the present invention by light irradiation may be insufficient, and if it exceeds 15 parts by weight, the hygroscopicity of the sealing agent of the present invention after curing may be kept low. It may not be possible.

The radical chain transfer agent reacts with the growing radical (P.) as shown in the following formula (1) to generate a new radical (T.), and further as shown in the following formula (2). The new radical (T.) produced by the reaction with the polymerizable compound (M) generates a growth radical (P1.). If the growth rate constant is Kp, it is necessary that Kp <k _tr .

P ・ + T → P + T ・ (1)
However, rightward reaction rate constant: k _tr

T ・ + M → P1 ・ (2)
However, rightward reaction rate constant: k _ri

Such a compound is not particularly limited. For example, a compound containing a mercapto group such as butanethiol, a compound having a disulfide bond such as diphenyl disulfide, a chemical formula (1)
Examples include Co (II) complexes represented by (3), and other compounds represented by chemical formulas (4) to (7).

In the formula (4), X represents Br, SR ¹ , SO ₂ Ar, Y represents CO ₂ R ² , Ph, CN, and R ¹ , R ² may be branched and has 9 or less carbon atoms. Represents a hydrocarbon group, Ar represents an unsubstituted or substituted Ph group. In formula (6), R ³ represents a hydrocarbon group having 9 or less carbon atoms, an unsubstituted Ph group or a substituted Ph group which may be branched. In formula (7), Z represents a C9 or less hydrocarbon group, unsubstituted Ph group, substituted Ph group, Br group or CN group which may be branched.
Among these, as the radical chain transfer agent in the sealant of the present invention, it is preferable to use a compound having a disulfide bond in terms of good reactivity as a chain transfer agent (that is, a large k _tr ).

The radical chain transfer agent preferably has iniferter properties. The above-mentioned iniferter property means a property that plays three roles of a radical polymerization initiator, a chain transfer agent, and a terminator. When the radical chain transfer agent has such an iniferter property, it gives heat and light energy. Can cause the reverse reaction of the above formula (1), so that it can be used particularly suitably to produce a relatively high molecular weight polymer while chain transfer.

Examples of the radical chain transfer agent having iniferter properties include dithiocarbamate compounds such as tetraethylthiuram disulfide, triphenylmethylazobenzene, and tetraphenylethane derivatives represented by the following chemical formula (8).

In the formula (8), W represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, a substituted phenyl group, CN
Group, OC ₆ H ₅ group and the like.
Among these, the dithiocarbamate compound has an excellent function as a compound having photo-iniferter properties, and can be particularly preferably used.

Content of the said radical chain transfer agent in the sealing agent of this invention is the said photocurable resin 100.
The lower limit is 0.001 part by weight and the upper limit is 1 part by weight with respect to parts by weight. If it is less than 0.001 part by weight, radical chain transfer cannot be sufficiently caused, and if it exceeds 1 part by weight,
The progress of the growth reaction becomes extremely slow and the polymerization does not proceed.

The sealing agent of the present invention contains a curing agent when the photocurable resin is a resin having both functions of radical polymerization by light and thermosetting, or when the thermosetting resin is contained. Also good.
The above curing agent is for reacting and crosslinking epoxy groups by heating, and can improve the adhesion and moisture resistance of the cured product, and also deteriorate the characteristics of the liquid crystal in the test of high temperature and high humidity operation. Can be suppressed.

Such a curing agent is not particularly limited, and examples thereof include metaphenylenediamine, diaminodiphenylmethane, dicyandiamide, guanidine derivatives, imidazole derivatives such as methylethylimidazole, and hydrazide compounds. These curing agents may be used alone or in combination of two or more.

The sealing agent of the present invention may contain a filler from the viewpoints of stress reduction and good shape retention after dispensing.
Examples of the filler include synthetic silica, calcium talc carbonate, magnesium carbonate,
Examples include titanium oxide. These fillers may be used independently and 2 or more types may be used together.

The average particle diameter of the filler is not particularly limited as long as it does not affect the cell gap between the transparent substrates of the liquid crystal display element to be produced, but a preferable upper limit is 2 μm.

The sealing agent of the present invention may contain a coupling agent for imparting adhesion.
The coupling agent is not particularly limited, and examples thereof include vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-glycosoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-aminopropyl. Silane coupling agents such as trimethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane; titanate coupling agents such as bis (triethanolamine) diisopropyl titanate, bis (triethanolamine) dibutyl titanate and diisopropyllauryl titanate Is mentioned. These coupling agents may be used independently and 2 or more types may be used together.

In the sealing agent of the present invention, if necessary, a thixotropic agent, a spacer for adjusting the panel gap, an antifoaming agent, a leveling agent, a polymerization inhibitor, a reactive diluent for adjusting the viscosity ,
A curing accelerator or the like may be blended.

The sealing agent of the present invention has a volume resistance value after curing of 1 × 10 ¹³ Ω · cm or more, and 1
The dielectric constant at 00 kHz is preferably 3 or more. Volume resistance is 1 × 10 ¹³ Ω
If it is less than cm, it means that ionic impurities are contained. When a liquid crystal display element is manufactured, the ionic impurities are eluted into the liquid crystal when energized, affecting the liquid crystal driving voltage, and display May cause unevenness. The dielectric constant of the liquid crystal is usually ε _// (parallel) is 10,
Since ε _⊥ (perpendicular) is about 3.5, when the dielectric constant at 100 kHz is less than 3, the sealing agent of the present invention is eluted in the liquid crystal, which affects the liquid crystal driving voltage and causes display unevenness. It may become.

In the sealing agent of the present invention, the preferable lower limit of the glass transition temperature after curing is 80 ° C., and the preferable upper limit is 150 ° C. When the temperature is lower than 80 ° C., the liquid crystal display element may be inferior in moisture resistance (high temperature and humidity resistance), and when it is higher than 150 ° C., it may be too rigid and inferior in adhesion to the substrate.

The method for producing the sealant of the present invention is not particularly limited, and examples thereof include a method of mixing the above-mentioned photocurable resin, photoradical polymerization initiator, radical chain transfer agent and the like by a conventionally known method. At this time, in order to remove ionic impurities, it may be brought into contact with an ion-adsorbing solid such as a layered silicate mineral.

Since the sealant of the present invention contains a photocurable resin, a photoradical polymerization initiator, and a radical chain transfer agent, the radical chain transfer agent is prevented from growing radicals even at sites that are not directly irradiated with light such as ultraviolet rays. By accepting radical species and radical polymerizing the photocurable resin as a new radical active species (chain transfer), it can be sufficiently cured. That is, even if a part of the sealant pattern formed on the transparent substrate overlaps with the black matrix or the wiring and there is a part that is not directly irradiated with light, it can be sufficiently cured.
Therefore, the sealing agent of the present invention is particularly suitable for the production of a liquid crystal panel excellent in adhesive strength reliability, environmental change reliability, and display non-contamination property even in a panel design in which a part thereof is not irradiated with light. Can be used.

Moreover, a vertical conduction material can be manufactured by mix | blending electroconductive fine particles with the sealing compound for liquid crystal display elements of this invention. If such a vertical conduction material is used, the electrode can be sufficiently conductively connected even if there is a portion where light such as ultraviolet rays is not directly irradiated.
The vertical conduction material containing the sealing agent for liquid crystal display elements 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.

The liquid crystal display element which uses the sealing compound for liquid crystal display elements of this invention and / or the vertical conduction material of this invention is also one of this invention.

According to the present invention, in the production of a liquid crystal display element, even if it is a site that is not directly irradiated with light,
A liquid crystal display that can be cured sufficiently, and that the components do not dissolve in the liquid crystal and cause liquid crystal contamination. An element sealing agent, a vertical conduction material, 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 Example 1) Synthesis of epoxy acrylate Resorcinol-type epoxy resin (manufactured by Nagase ChemteX Corporation, “Denacol EX-201”
) 120 g is dissolved in 500 mL of toluene, and triphenylphosphine 0.
1 g was added to make a uniform solution. To this solution, 70 g of acrylic acid was added dropwise with stirring under reflux over 2 hours, followed by further stirring under reflux for 8 hours.
Next, by removing toluene, an epoxy acrylate (EX-201 completely modified product: viscosity 60 Pa) in which all epoxy groups were converted to acryloyl groups was obtained.

(Synthesis Example 2) Synthetic phenol novolac type epoxy resin ("N-770", manufactured by Dainippon Ink & Chemicals, Inc.) 190, which is a novolak type epoxy resin obtained by reacting a part of the epoxy group with acrylic acid
g was dissolved in 500 mL of toluene, and 0.1 g of triphenylphosphine was added to this solution to obtain a uniform solution. To this solution, 35 g of acrylic acid was added dropwise with stirring under reflux over 2 hours, followed by further stirring under reflux for 6 hours.
Next, novolak-type solid modified epoxy resin (partially modified resin) in which 50% of epoxy groups reacted with (meth) acrylic acid was obtained by removing toluene.
The ratio of the epoxy group reacted with acrylic acid was measured by a method in which the obtained resin was dissolved in a hydrochloric acid-dioxane solution, and then the amount of hydrochloric acid consumed by the epoxy group was titrated with KOH.

(Examples 1-6, Comparative Examples 1-3)
Each raw material of the specified blending amount shown in Table 1 is made into a planetary stirrer (Awatori Nerita: manufactured by Shinky Corporation)
After mixing using, sealing agents of Examples 1 to 6 and Comparative Examples 1 to 3 were obtained by further mixing using three rolls. In Table 1, “Irgacure 907” manufactured by Ciba Specialty Chemicals is used as the photoradical initiator, and “Amicure VDH-J” manufactured by Ajinomoto Fine Techno Co. is used as the hydrazide type thermosetting agent. As a glycidyl group-containing silane coupling agent, “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd. was used, and “SO-C1” manufactured by Admatechs Co., Ltd. was used as a silica filler.

(Production of liquid crystal display panel)
A liquid crystal display panel was produced using the obtained sealant.
That is, first, a black matrix (BM) and a substrate with a transparent electrode were formed on Examples 1 to 1 obtained.
6 and Comparative Examples 1 to 3 were applied with a dispenser so as to draw a rectangular frame.
Subsequently, liquid droplets (manufactured by Chisso Corporation: “JC-5004LA”) are finely applied onto the entire surface of the sealant pattern frame of the transparent substrate, and another substrate with a transparent electrode (without BM) is immediately superimposed. Using a high-pressure mercury lamp from the substrate side with BM to the sealant pattern part, 50mW / UV
Irradiated with cm ² for 20 seconds. At this time, the line width of the squeezed sealant was about 1.2 mm, and 0.3 mm was drawn so as to overlap with BM. Then, liquid crystal annealing is performed for 12
This was carried out at 0 ° C. for 1 hour, and at the same time, the sealant was thermally cured to produce a liquid crystal display panel.

(Evaluation)
The following evaluation was performed about the sealing agent and liquid crystal display panel which were obtained in Examples 1-6 and Comparative Examples 1-3. The evaluation results are shown in Table 1.

(1) Adhesive strength With respect to 100 parts by weight of the obtained sealant, polymer beads having an average particle diameter of 5 μm (
3 parts by weight of Sekisui Chemical Co., Ltd .: Micropearl SP) is dispersed with a planetary stirrer to form a uniform liquid, and a very small amount of Corning Glass 1737 (20 mm × 50 mm × 1.1 mm)
At the center of t), the same type of glass was placed on top to spread the sealing agent, and ultraviolet rays were irradiated at 50 mW / cm ² for 60 seconds.
Thereafter, heating was performed at 120 ° C. for 1 hour to obtain an adhesion test piece. The adhesion strength of this adhesion test piece was measured using a tension gauge (comparative unit: N / cm ² ).

(2) Measurement of conversion rate of acrylic group under pattern after UV irradiation First, a substrate 10 on which half of a Corning glass having a thickness of 0.7 mm was vapor-deposited on chromium and a substrate 11 on which front surface was vapor-deposited with chromium were separately prepared (see FIG. 1). ).
Next, after applying a sealing agent 12 containing polymer beads (manufactured by Sekisui Chemical Co., Ltd .: Micropearl SP) to the central portion of the substrate 10 (the boundary between the chromium vapor-deposited portion and the non-vapor-deposited portion), and bonding the substrate 11 together. The sealant 12 is sufficiently crushed, and ultraviolet rays are emitted from the side of the substrate 10 at 50 mW / cm ² .
Irradiation was for 0 seconds (see FIG. 2).
Thereafter, the substrates 10 and 11 are peeled off by using a cutter, and a UV direct irradiation part (place 1) and a point 100 μm away from the direct irradiation part (place 2), a point 200 μm away (place 3) and The spectrum of the sealant on a point (location 4) separated by 300 μm was measured, and the conversion rate of the acrylic group in the sealant was determined from each spectrum by the following method.
That is, the peak area (815 to 800 cm ⁻¹ ) of the acrylic group is changed to the reference peak area (
845-820 cm < ^-1 >), and the conversion rate was computed by the following formula.

Conversion ratio of acrylic group = {1- (peak area of acrylic group after curing / reference peak area after curing) / (peak area of acrylic group before curing / reference peak area before curing)
} × 100

(3) Evaluation of liquid crystal panel display unevenness For the obtained liquid crystal display panel, color unevenness generated in the liquid crystal around the seal portion was visually observed, and ◎ (no color unevenness), ○ (no color unevenness), △ (Slight color unevenness), ×
Evaluation was performed in four stages (there was considerable color unevenness).

(4) Evaluation of panel display unevenness after aging The obtained liquid crystal display panel was allowed to stand in an atmosphere of 80 ° C. for 100 hours in a state where a DC voltage of 5 V was applied. Observation was made and evaluated in four stages: ◎ (no color unevenness at all), ○ (little color unevenness), Δ (a little color unevenness), × (color unevenness was considerable).

As is clear from the results shown in Table 1, the adhesive strength of the sealing agents obtained in Examples 1 to 6, and
Although the adhesive strength of the sealing agents obtained in Comparative Examples 1 to 3 was substantially equivalent, the acrylic group conversion rate under the pattern after UV irradiation of the sealing agents obtained in Comparative Examples 1 to 3 The reduction in conversion rate was larger than that of the sealant obtained in No. 6, and particularly in the place 4, all were 0%.
In addition, in the liquid crystal panels of Comparative Examples 1 to 3, considerable display unevenness was observed regardless of the presence or absence of aging.

According to the present invention, in the production of a liquid crystal display element, even if it is a site that is not directly irradiated with light,
A liquid crystal display that can be cured sufficiently, and that the components do not dissolve in the liquid crystal and cause liquid crystal contamination. An element sealing agent, a vertical conduction material, and a liquid crystal display element can be provided.

It is a top view which shows the board | substrate used for the measurement of the acrylic group conversion rate under the pattern after ultraviolet irradiation of the sealing agent obtained by the Example and the comparative example. It is a perspective view explaining the measuring method of the acrylic group conversion under a pattern after ultraviolet irradiation of the sealing agent obtained by the Example and the comparative example. It is a top view explaining the measuring method of the acrylic group conversion under the pattern after ultraviolet irradiation of the sealing agent obtained by the Example and the comparative example.

Explanation of symbols

10 Substrate 11 Substrate 12 Sealant

Claims (5)

A sealant for a liquid crystal display element comprising a photocurable resin, a photoradical polymerization initiator and a radical chain transfer agent,
A sealing agent for liquid crystal display elements, comprising 0.001 to 1 part by weight of the radical chain transfer agent with respect to 100 parts by weight of the photocurable resin. 2. The sealing agent for a liquid crystal display element according to claim 1, wherein the radical chain transfer agent is a compound having a disulfide bond. 3. The sealant for a liquid crystal display element according to claim 1, wherein the radical chain transfer agent has an iniferter property. A vertical conduction material comprising the liquid crystal display element sealing agent according to claim 1, 2 or 3 and conductive fine particles. A liquid crystal display element comprising the sealant for a liquid crystal display element according to claim 1, 2 or 3, and / or the vertical conduction material according to claim 4.

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