JP2012048230A - Sealing agent for liquid crystal one-drop-fill process and liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing agent for a liquid crystal one-drop-fill process, the agent showing excellent adhesiveness and preventing property against intrusion of a liquid crystal during heating and hardly causing contamination of the liquid crystal, and to provide a liquid crystal display element manufactured by using the sealing agent for a liquid crystal one-drop-fill process.SOLUTION: The sealing agent for a liquid crystal one-drop-fill process contains a curable resin containing a (meth)acryloyloxy group, a thermo-radical polymerization initiator and a gelling agent.

Description

The present invention relates to a sealing agent for a liquid crystal dropping method which is excellent in adhesiveness and prevention of liquid crystal insertion during heating and hardly causes liquid crystal contamination. Moreover, this invention relates to the liquid crystal display element manufactured using this sealing compound for liquid crystal dropping methods.

In recent years, a method for manufacturing a liquid crystal display element such as a liquid crystal display cell has been disclosed in, for example, Patent Document 1 and Patent Document 2 from the conventional vacuum injection method from the viewpoint of shortening tact time and optimizing the amount of liquid crystal used. Such a photocurable resin, a photopolymerization initiator, a thermosetting resin, and a liquid crystal dropping method called a dropping method using a light and heat combined curing type sealant containing a thermosetting agent are being replaced.
In the dropping method, first, a rectangular seal pattern is formed on one of two transparent substrates with electrodes by dispensing. Next, a liquid crystal micro-droplet is dropped on the entire surface of the transparent substrate frame with the sealant being uncured, and the other transparent substrate is immediately overlaid, and the seal portion is irradiated with light such as ultraviolet rays to perform temporary curing. . Thereafter, heating is performed at the time of liquid crystal annealing to perform main curing, and a liquid crystal display element is manufactured. If the substrates are bonded together under reduced pressure, a liquid crystal display element can be manufactured with extremely high efficiency, and this dripping method is currently the mainstream method for manufacturing liquid crystal display elements.

By the way, in the present age when mobile devices with various liquid crystal panels such as mobile phones and portable game machines are widespread, downsizing of devices is the most demanded issue. As a technique for miniaturization, there is a narrow frame of the liquid crystal display unit, and for example, the position of the seal portion is arranged under the black matrix (hereinafter also referred to as a narrow frame design).

However, when the dripping method is performed with a narrow frame design, there is a portion where the black matrix does not receive light on the seal portion, so there is a portion of a photocurable resin that does not sufficiently irradiate light and does not proceed with curing, and a temporary curing step Later, uncured photocurable resin was eluted, and there was a problem that liquid crystal was contaminated and liquid crystal display unevenness occurred.
In order to irradiate the seal part under the black matrix without fail, a method of irradiating light from the back side of the substrate, that is, from the array side is conceivable. However, metal wiring, transistors, etc. also exist on the array substrate. There is a problem that there is a place where the seal portion is not exposed to light.

Therefore, it has been studied to cure the sealant only by heat, but without pre-curing by photopolymerization, the liquid crystal flows when heated and inserted into the sealant part during curing, resulting in tearing of the seal pattern, etc. There was a problem to do.
In particular, in recent years, as the panel is made narrower, the width of the sealing agent to be dispensed has been reduced, and the cross-sectional area of the seal after bonding has been reduced. Therefore, the seal pattern is more likely to be broken.

JP 2001-133794 A International Publication No. 02/092718 Pamphlet

An object of the present invention is to provide a sealing agent for a liquid crystal dropping method that is excellent in adhesiveness and prevention of liquid crystal insertion during heating and hardly causes liquid crystal contamination. Moreover, this invention aims at providing the liquid crystal display element manufactured using this sealing compound for liquid crystal dropping methods.

The present invention is a sealing agent for a liquid crystal dropping method containing a curable resin containing a resin having a (meth) acryloyloxy group, a thermal radical polymerization initiator, and a gelling agent.
The present invention is described in detail below.

The present inventor conducted a detailed analysis on the insertion of the sealant part, the tearing of the seal pattern, etc. that occur when the sealant for liquid crystal dropping method (hereinafter also simply referred to as “sealant”) is cured only by heat. went. The insertion of the sealant part or the tearing of the seal pattern is caused by the viscosity of the sealant being lowered by heating during curing, and the seal pattern cannot withstand the flow of liquid crystal. Then, this inventor considered preventing the insertion of a sealing agent part and the tearing of a sealing pattern by making the viscosity of a sealing agent high by mix | blending a gelatinizer with a sealing agent. However, even if the viscosity of the sealant was increased by actually adding a gelling agent, the seal pattern shape could be maintained from around room temperature to around 60-80 ° C, but in a region higher than 60-80 ° C. However, it was not possible to prevent the sealant part from being inserted or the seal pattern from being broken. Although increasing the blending amount of the gelling agent to further increase the viscosity of the sealing agent was studied, in that case, it became difficult to draw a seal pattern using a dispenser.

This inventor examined the reason why the insertion of the sealant part or the tearing of the seal pattern in a region higher than 60 to 80 ° C. cannot be prevented only by blending the gelling agent. As a result, it was found that there was a problem in the heat curing temperature and the heat curing rate of the conventional sealant.
Liquid crystals are known to exhibit higher fluidity at temperatures higher than the phase transition (nematic-isotropic phase transition) temperature. The phase transition temperature of a liquid crystal generally used in a liquid crystal display device is around 90 ° C. On the other hand, a conventional thermosetting sealant performs a curing reaction using a thermosetting agent, and the reaction start temperature of the thermosetting reaction by the thermosetting agent is around 120 ° C. For this reason, the seal pattern cannot be withstood between the phase transition temperature (around 90 ° C.) at which the fluidity of the liquid crystal rapidly increases and the temperature near 120 ° C. at which the sealing agent begins to harden. It seemed that tears of the sword would occur. Furthermore, the curing reaction with the thermosetting agent also has a slow reaction rate after the start of the reaction, so the viscosity increase due to the crosslinking reaction of the sealing agent is slow, and the reaction does not proceed following the decrease in the viscosity of the sealing agent. It seems that this was the cause of the insertion of the part and the tear of the seal pattern.

As a result of further intensive studies, the present inventor, in addition to adjusting the viscosity with a gelling agent, by using a combination of a curable resin containing a resin having a (meth) acryloyloxy group and a thermal radical polymerization initiator, It has been found that it is possible to effectively prevent the sealant part from being inserted and the seal pattern from being broken. That is, the insertion of the sealant part and the occurrence of tearing of the seal pattern from around room temperature to around 60-80 ° C. can be prevented by blending the gelling agent and keeping the viscosity of the sealant within a specific range. it can. On the other hand, in the region higher than 60 to 80 ° C., in addition to the blending of the gelling agent, the reaction start temperature is relatively low, and once the reaction starts, the reaction proceeds rapidly and the viscosity increases ( ) By using a combination of a curable resin containing a resin having an acryloyloxy group and a thermal radical polymerization initiator, the insertion of the sealant or the tearing of the seal pattern occurs against the increase in fluidity of the liquid crystal. Can be prevented.

The sealing agent for liquid crystal dropping method of the present invention contains a curable resin.
The curable resin contains a resin having a (meth) acryloyloxy group. By using a resin having a (meth) acryloyloxy group in combination with a thermal radical polymerization initiator, the viscosity of the sealant can be increased rapidly after the reaction starts.

The resin having the (meth) acryloyloxy group preferably contains an epoxy (meth) acrylate.
In addition, in this specification, the said (meth) acryloyloxy group means an acryloyloxy group or a methacryloyloxy group, and (meth) acrylate means an acrylate or a methacrylate. Moreover, in this specification, the said epoxy (meth) acrylate represents the compound which made all the epoxy groups in an epoxy resin react with (meth) acrylic acid.

The epoxy (meth) acrylate is not particularly limited, and examples thereof include those obtained by reacting (meth) acrylic acid and an epoxy resin in the presence of a basic catalyst according to a conventional method.
In addition, in this specification, (meth) acryl means acryl or methacryl.

The epoxy resin used as a raw material for synthesizing the epoxy (meth) acrylate is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, 2,2′-diallylbisphenol A Type epoxy resin, hydrogenated bisphenol type epoxy resin, propylene oxide added bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, sulfide type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy Resin, phenol novolac epoxy resin, orthocresol novolac epoxy resin, dicyclopentadiene novolac epoxy resin, biphenyl novolac epoxy resin Naphthalene phenol novolac-type epoxy resin, glycidyl amine type epoxy resin, alkyl polyol type epoxy resin, rubber modified epoxy resin, glycidyl ester compounds, bisphenol A type episulfide resins.

Examples of commercially available bisphenol A type epoxy resins include Epicoat 828EL, Epicoat 1001, Epicoat 1004 (all manufactured by Mitsubishi Chemical Corporation), Epicron 850-S (manufactured by DIC Corporation), and the like.
As what is marketed among the said bisphenol F type epoxy resins, Epicoat 806, Epicoat 4004 (all are Mitsubishi Chemical Corporation make) etc. are mentioned, for example.
As what is marketed among the said bisphenol S-type epoxy resins, Epicron EXA1514 (made by DIC Corporation) etc. are mentioned, for example. As what is marketed among the said 2,2'- diallyl bisphenol A type epoxy resins, RE-810NM (made by Nippon Kayaku Co., Ltd.) etc. are mentioned, for example.
As what is marketed among the said hydrogenated bisphenol type | mold epoxy resins, Epicron EXA7015 (made by DIC Corporation) etc. are mentioned, for example.
As what is marketed among the said propylene oxide addition bisphenol A type epoxy resins, EP-4000S (made by ADEKA) etc. are mentioned, for example.
As what is marketed among the said resorcinol type epoxy resins, EX-201 (made by Nagase ChemteX Corporation) etc. are mentioned, for example.
As what is marketed among the said biphenyl type epoxy resins, Epicoat YX-4000H (made by Mitsubishi Chemical Corporation) etc. are mentioned, for example.
As what is marketed among the said sulfide type epoxy resins, YSLV-50TE (made by Nippon Steel Chemical Co., Ltd.) etc. are mentioned, for example.
As what is marketed among the said diphenyl ether type epoxy resins, YSLV-80DE (made by Nippon Steel Chemical Co., Ltd.) etc. are mentioned, for example.
As what is marketed among the said dicyclopentadiene type epoxy resins, EP-4088S (made by ADEKA) etc. are mentioned, for example.
Examples of the naphthalene type epoxy resin include Epicron HP4032, Epicron EXA-4700 (both manufactured by DIC Corporation), and the like.
As what is marketed among the said phenol novolak-type epoxy resins, Epicron N-770 (made by DIC Corporation) etc. are mentioned, for example.
As what is marketed among the said ortho cresol novolak-type epoxy resins, Epicron N-670-EXP-S (made by DIC) etc. are mentioned, for example.
As what is marketed among the said dicyclopentadiene novolak-type epoxy resins, epiclone HP7200 (made by DIC) etc. are mentioned, for example.
As what is marketed among the said biphenyl novolak-type epoxy resins, NC-3000P (made by Nippon Kayaku Co., Ltd.) etc. are mentioned, for example.
As what is marketed among the said naphthalene phenol novolak-type epoxy resins, ESN-165S (made by Nippon Steel Chemical Co., Ltd.) etc. are mentioned, for example.
As what is marketed among the said glycidylamine type epoxy resins, Epicoat 630 (made by Mitsubishi Chemical Corporation), Epicron 430 (made by DIC Corporation), TETRAD-X (made by Mitsubishi Gas Chemical Co., Inc.) etc. are mentioned, for example.
Examples of commercially available alkyl polyol type epoxy resins include ZX-1542 (manufactured by Nippon Steel Chemical Co., Ltd.), Epicron 726 (manufactured by DIC Corporation), Epolite 80MFA (manufactured by Kyoeisha Chemical Co., Ltd.), Denacol EX- 611 (manufactured by Nagase ChemteX Corporation).
Examples of commercially available rubber-modified epoxy resins include YR-450, YR-207 (all manufactured by Nippon Steel Chemical Co., Ltd.), Epolide PB (manufactured by Daicel Chemical Industries, Ltd.), and the like.
As what is marketed among the said glycidyl ester compounds, Denacol EX-147 (made by Nagase ChemteX Corporation) etc. is mentioned, for example.
As what is marketed among the said bisphenol A type | mold episulfide resin, Epicoat YL-7000 (made by Mitsubishi Chemical Corporation) etc. are mentioned, for example.
Other commercially available epoxy resins include, for example, YDC-1312, YSLV-80XY, YSLV-90CR (all manufactured by Nippon Steel Chemical Co., Ltd.), XAC4151 (manufactured by Asahi Kasei Co., Ltd.), Epicoat 1031, and Epicoat. 1032 (all manufactured by Mitsubishi Chemical Corporation), EXA-7120 (manufactured by DIC Corporation), TEPIC (manufactured by Nissan Chemical Industries, Ltd.) and the like.

Examples of commercially available epoxy (meth) acrylates include EBECRYL860, EBECRYL3200, EBECRYL3201, EBECRYL3412, EBECRYL3600, EBECRYL3700, EBECRYL3701, EBECRYL3702, EBECRYL3703, EA-1010, EA-1020, EA-5323, EA-5520, EA-CHD, EMA-1020 (all manufactured by Shin-Nakamura Chemical Co., Ltd.), epoxy ester 40EM, epoxy ester 70PA, epoxy ester 80MFA, epoxy ester 200EA, Epoxy ester 200PA, D Xyester 400EA, Epoepoxy ester 1600A, Epoxy ester 3000A, Epoxy ester 3000M, Epoxy ester 3002A, Xyester 3002M, Epoxy ester M-600A (all manufactured by Kyoeisha Chemical Co., Ltd.), Denacol acrylate DA-141, Denacol acrylate DA -314, Denacol acrylate DA-911 (all manufactured by Nagase ChemteX Corporation) and the like.

Although the weight average molecular weight of the said epoxy (meth) acrylate is not specifically limited, A preferable minimum is 300 and a preferable upper limit is 10,000. When the weight average molecular weight of the epoxy (meth) acrylate is less than 300, the viscosity of the obtained liquid crystal dropping method sealing agent becomes low, and the insertion of liquid crystal may not be sufficiently prevented. When the weight average molecular weight of the said epoxy (meth) acrylate exceeds 10,000, the sealing agent for liquid crystal dropping methods obtained may become inferior to applicability | paintability. The minimum with a more preferable weight average molecular weight of the said epoxy (meth) acrylate is 500, and a more preferable upper limit is 3000.
In addition, in this specification, the said weight average molecular weight is a value calculated | required by polystyrene conversion by measuring with gel permeation chromatography (GPC). Examples of the column for measuring the weight average molecular weight in terms of polystyrene by GPC include Shodex LF-804 (manufactured by Showa Denko KK).

The content of the epoxy (meth) acrylate having a weight average molecular weight of 300 to 10,000 is not particularly limited, but is preferably 60 to 95% by weight of the total amount of the curable resin. When the content of the epoxy (meth) acrylate having a weight average molecular weight of 300 to 10,000 is less than 60% by weight, the polarity of the obtained sealing agent for liquid crystal dropping method is lowered, and the contamination property to the liquid crystal may be deteriorated. There is. When the content of the epoxy (meth) acrylate having a weight average molecular weight of 300 to 10,000 exceeds 95% by weight, the obtained sealing agent for liquid crystal dropping method may be inferior in adhesiveness. The more preferable lower limit of the content of the epoxy (meth) acrylate having a weight average molecular weight of 300 to 10,000 is 75% by weight, and the more preferable upper limit is 90% by weight.

Examples of the resin having a (meth) acryloyloxy group other than the epoxy (meth) acrylate include an ester compound obtained by reacting a compound having a hydroxyl group with (meth) acrylic acid, and a hydroxyl group in the isocyanate ( Examples thereof include urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative.

The ester compound obtained by reacting the (meth) acrylic acid with a compound having a hydroxyl group is not particularly limited, and examples of the monofunctional ester compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meta ) Acrylate, 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, phenoxy polyethylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) Acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, imide (meth) Acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, Rohexyl (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, succinic acid 2- (meth) acryloyloxyethyl, 2- (meth) acryloyl Roxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl 2-hydroxypropyl phthalate, glycidyl (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate, etc. It is done.

Bifunctional ester compounds include, for example, 1,4-butanediol di (meth) acrylate, 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 dicyclopentadienyl di (meth) acrylate, 1,3-butylene Glycol 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.

The trifunctional or higher functional ester compounds include, for example, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, propylene oxide-added trimethylolpropane tri (meth) acrylate, and 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) acrylate, Pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, propylene oxide-added glyce Entry (meth) acrylate, tris (meth) acryloyloxyethyl phosphate, and the like.

The urethane (meth) acrylate obtained by reacting the isocyanate with a (meth) acrylic acid derivative having a hydroxyl group is, for example, a (meth) acrylic acid derivative 2 having a hydroxyl group with respect to 1 equivalent of a compound having two isocyanate groups. The equivalent weight can be obtained by reacting in the presence of a catalytic amount of a tin-based compound.

Isocyanate that is a raw material of urethane (meth) acrylate obtained by reacting a hydroxyl group-containing (meth) acrylic acid derivative with the isocyanate is not particularly limited. 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 Range Iocyanate (XDI), Hydrogenated XDI, Lysine Diisocyanate, Triphenylmethane Triisocyanate, Tris (Isocyanate Phenyl) Thioff Sufeto, tetramethyl xylene diisocyanate, 1,6,10- undecene country isocyanate.

Moreover, the isocyanate used as the raw material of the urethane (meth) acrylate obtained by making the said isocyanate react with the (meth) acrylic acid derivative which has a hydroxyl group is not specifically limited, For example, ethylene glycol, glycerol, sorbitol, a trimethylol propane, Chain-extended isocyanate compounds obtained by reaction of polyols such as (poly) propylene glycol, carbonate diol, polyether diol, polyester diol, polycaprolactone diol and excess isocyanate can also be used.

The (meth) acrylic acid derivative having a hydroxyl group, which is a raw material for urethane (meth) acrylate obtained by reacting the isocyanate with a (meth) acrylic acid derivative having a hydroxyl group, is not particularly limited. For example, 2-hydroxyethyl Commercial products such as (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, ethylene glycol, propylene glycol, 1,3-propanediol, 1 Mono (meth) acrylates of divalent alcohols such as 1,3-butanediol, 1,4-butanediol and polyethylene glycol, mono (meth) acrylates of trivalent alcohols such as trimethylolethane, trimethylolpropane and glycerin, or (Meth) acrylate, epoxy (meth) acrylates such as bisphenol A type epoxy acrylate.

Examples of commercially available urethane (meth) acrylates include M-1100, M-1200, M-1210, and M-1600 (all manufactured by Toagosei Co., Ltd.), Evecryl 210, Evekril 220, Evekril 230. , Evecril 270, Evekril 1290, Evekrill 2220, Evekril 4827, Evekril 4842, Evekril 4858, Evekril 5129, Evekril 6700, Evekrill 8803, Evekril 8804, Evekril 8807, Eveklycyl 9260 Tech UN-330, Art Resin SH-500B, Art Resin UN-1200TPK, Art Resin UN-1255, Art Resin UN-3320HB, Art Resin UN- 100, art resin UN-9000A, art resin UN-9000H (all manufactured by Negami Kogyo Co., Ltd.), U-2HA, U-2PHA, U-3HA, U-4HA, U-6H, U-6LPA, U-6HA, U-10H, U-15HA, U-122A, U-122P, U-108, U-108A, U-324A, U-340A, U-340P, U-1084A, U-2061BA, UA-340P, UA- 4100, UA-4000, UA-4200, UA-4400, UA-5201P, UA-7100, UA-7200, UA-W2A (all manufactured by Shin-Nakamura Chemical Co., Ltd.), AI-600, AH-600, AT- 600, UA-101I, UA-101T, UA-306H, UA-306I, UA-306T (all manufactured by Kyoeisha Chemical Co., Ltd.) and the like. That.

The resin having the (meth) acryloyloxy group preferably has a hydrogen bonding unit such as —OH group, —NH— group, and —NH ₂ group from the viewpoint of suppressing adverse effects on the liquid crystal.
In addition, the resin having the (meth) acryloyloxy group is preferably one having 2 to 3 (meth) acryloyloxy groups in the molecule because of high reactivity.

The curable resin preferably further contains a resin having an epoxy group for the purpose of improving the adhesiveness of the obtained liquid crystal dropping method sealing agent. The resin having the epoxy group is not particularly limited, and examples thereof include an epoxy resin that is a raw material for synthesizing the epoxy (meth) acrylate and a partial (meth) acryl-modified epoxy resin.
In the present specification, the partial (meth) acryl-modified epoxy resin means a resin having one or more epoxy groups and (meth) acryloyloxy groups in one molecule, for example, two or more epoxy resins. It can be obtained by reacting an epoxy group of a part of the resin having a group with (meth) acrylic acid.

Although the weight average molecular weight of the said resin which has an epoxy group is not specifically limited, A preferable minimum is 100 and a preferable upper limit is 8000. When the weight average molecular weight of the resin having an epoxy group is less than 100, the viscosity of the obtained sealing agent for liquid crystal dropping method may be low, and the insertion of liquid crystal may not be sufficiently prevented. When the weight average molecular weight of the epoxy group-containing resin exceeds 8000, the obtained sealing agent for liquid crystal dropping method may be inferior in coatability. The more preferable lower limit of the weight average molecular weight of the resin having an epoxy group is 500, and the more preferable upper limit is 3000.

Although content of the resin which has the said epoxy group is not specifically limited, It is preferable that it is 5 to 40 weight% of the said curable resin whole quantity. If the content of the epoxy group-containing resin is less than 5% by weight, there is a possibility that sufficient adhesive force to the substrate of the obtained liquid crystal dropping method sealing agent may not be obtained. If the content of the resin having an epoxy group exceeds 40% by weight, the resulting liquid crystal dropping method sealing agent may have poor contamination with liquid crystals. A more preferable lower limit of the content of the resin having an epoxy group is 8% by weight, and a more preferable upper limit is 15% by weight.

The sealing agent for liquid crystal dropping method of the present invention contains a thermal radical polymerization initiator. The sealing agent for liquid crystal dropping method of the present invention is quickly thermoset by using a combination of the curable resin containing the resin having the (meth) acryloyloxy group and the thermal radical polymerization initiator.

The above-mentioned thermal radical initiator has a preferred lower limit of 10 hours half-life temperature of 40 ° C and a preferred upper limit of 100 ° C. When the preferable lower limit of the 10-hour half-life temperature is less than 40 ° C., the storage stability of the sealant may be deteriorated or the workability may be deteriorated. When the temperature exceeds 100 ° C., the reaction start temperature is high, and the liquid crystal Since the reaction starts at a temperature higher than the phase transition temperature, it may be difficult to maintain a sufficient viscosity during the phase transition of the liquid crystal. The more preferable lower limit of the 10-hour half-life temperature of the thermal radical initiator is 60 ° C, and the more preferable upper limit is 80 ° C.

The thermal radical polymerization initiator is not particularly limited, and examples thereof include peroxides and azo compounds. Of these, polymer azo compounds are preferred.
The high molecular azo compound means a compound having an azo group and having a molecular weight of 300 or more for generating a radical capable of curing a (meth) acryl group with heat.
In addition, since the said polymeric azo compound decomposes | disassembles also by light irradiation normally and generate | occur | produces a radical, it can function also as a photo radical initiator.

The preferable lower limit of the number average molecular weight of the polymer azo compound is 1000, and the preferable upper limit is 300,000. When the number average molecular weight of the polymer azo compound is less than 1000, the polymer azo compound may adversely affect the liquid crystal, and when it exceeds 300,000, mixing with a resin having a (meth) acryl group becomes difficult. May be. The more preferable lower limit of the number average molecular weight of the polymer azo compound is 5000, the more preferable upper limit is 100,000, the still more preferable lower limit is 10,000, and the still more preferable upper limit is 90,000.

Examples of the polymer azo compound include those having a structure in which a plurality of units such as polydimethylsiloxane and polyalkylene oxide are bonded via an azo group.
As a structure in which a plurality of units such as polyalkylene oxide are bonded, those having a polyethylene oxide structure are preferable.
Examples of such polymer azo compounds include polycondensates of 4,4′-azobis (4-cyanopentanoic acid) and polyalkylene glycol, and 4,4′-azobis (4-cyanopentanoic acid) with terminal amino acids. And a polycondensate of polydimethylsiloxane having a group.

Examples of commercially available thermal radical polymerization initiators include V-30, V-501, VPE-0201, VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001 ( All of them are manufactured by Wako Pure Chemical Industries, Ltd.), perbutyl O, perhexyl O, perbutyl PV (all manufactured by NOF Corporation) and the like.

Although content of the said thermal radical polymerization initiator is not specifically limited, A preferable minimum is 0.1 weight part with respect to 100 weight part of said curable resins, and a preferable upper limit is 30 weight part. If the content of the thermal radical polymerization initiator is less than 0.1 parts by weight, the curing reaction may not proceed sufficiently. If it exceeds 30 parts by weight, the liquid crystal is contaminated or the viscosity of the sealing agent is stable. Sometimes lacking sex. The more preferred lower limit of the content of the thermal radical polymerization initiator is 0.5 parts by weight, the more preferred upper limit is 10 parts by weight, the still more preferred lower limit is 1 part by weight, and the still more preferred upper limit is 6 parts by weight.

The sealing agent for liquid crystal dropping method of the present invention contains a gelling agent for the purpose of increasing the viscosity at high temperature and preventing the insertion of liquid crystal during heating.
The gelling agent is not particularly limited, and examples thereof include acrylic fine particles. Among them, core-shell type acrylic fine particles in which the core layer is made of an acrylate resin having a glass transition temperature (Tg) below room temperature and the shell layer is made of an acrylate resin having a glass transition temperature (Tg) in a higher temperature range than the core layer. Is preferred. Examples of such commercially available acrylic resins include core-shell acrylate copolymer fine particles “F351” and polymethyl methacrylate fine particles “F325” manufactured by Ganz Kasei Co., Ltd. Of these, F325 is preferably used.

As for the content of the gelling agent, a preferable lower limit with respect to 100 parts by weight of the curable resin is 1 part by weight, and a preferable upper limit is 40 parts by weight. When the content of the gelling agent is less than 1 part by weight, viscosity adjustment is insufficient, and the seal pattern may be broken by inserting the liquid crystal. The sealing agent for construction method is inferior in applicability (dispensability). The minimum with more preferable content of the said gelatinizer is 5 weight part, and a more preferable upper limit is 20 weight part.

The sealing agent for liquid crystal dropping method of the present invention may further contain a radical photopolymerization initiator. By containing the photo radical polymerization initiator, photocurability can be imparted to the obtained sealing agent for liquid crystal dropping method.

The photo radical polymerization initiator is not particularly limited, and examples thereof include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, benzyl, and thioxanthone. .
Examples of commercially available photo radical polymerization initiators include Irgacure 184, Irgacure 369, Irgacure 379, Irgacure 651, Irgacure 819, Irgacure 907, Irgacure 2959, Irgacure OXE01, and Lucillin TPO (all of which are BASF Japan). Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether (all of which are manufactured by Tokyo Chemical Industry Co., Ltd.) and the like.

Although content of the said radical photopolymerization initiator is not specifically limited, A preferable minimum is 1 weight part and a preferable upper limit is 10 weight part with respect to 100 weight part of said curable resins. If the content of the radical photopolymerization initiator is less than 1 part by weight, the photopolymerization may not proceed sufficiently or the reaction may become too slow. When the content of the radical photopolymerization initiator exceeds 10 parts by weight, workability may be deteriorated or the reaction may become uneven. The minimum with more preferable content of radical photopolymerization initiator is 2 weight part, and a more preferable upper limit is 5 weight part.

Moreover, when the said curable resin contains the resin which has the said epoxy group, it is preferable that the sealing compound for liquid crystal dropping methods of this invention contains a thermosetting agent.
The said thermosetting agent is not specifically limited, For example, organic acid hydrazide, an imidazole derivative, an amine compound, a polyhydric phenol type compound, an acid anhydride etc. are mentioned. Among these, solid organic acid hydrazide is preferably used.

The solid organic acid hydrazide is not particularly limited, and examples thereof include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, malonic acid dihydrazide, and the like. All include Ajinomoto Fine Techno Co., Ltd.), ADH, SDH (both manufactured by Otsuka Chemical Co., Ltd.) and the like.

Although content of the said thermosetting agent is not specifically limited, A preferable minimum is 3 weight part and a preferable upper limit is 10 weight part with respect to 100 weight part of said curable resins. If the content of the thermosetting agent is less than 3 parts by weight, the thermosetting may not proceed sufficiently or the reaction may become too slow. When content of the said thermosetting agent exceeds 10 weight part, workability | operativity may fall or reaction may become non-uniform | heterogenous. The minimum with more preferable content of the said thermosetting agent is 4 weight part, and a more preferable upper limit is 8 weight part.

The sealing agent for liquid crystal dropping method of the present invention preferably contains a filler for the purpose of improving the viscosity, improving the adhesiveness due to the stress dispersion effect, improving the linear expansion coefficient, and the like.
The filler is not particularly limited. For example, talc, asbestos, silica, diatomaceous earth, smectite, bentonite, calcium carbonate, magnesium carbonate, alumina, montmorillonite, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, magnesium hydroxide Organic fillers such as aluminum hydroxide, glass beads, silicon nitride, barium sulfate, gypsum, calcium silicate, sericite activated clay, aluminum nitride, polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, acrylic polymer fine particles, etc. A filler is mentioned.

The content of the filler is not particularly limited, but is preferably 10 parts by weight or more and less than 80 parts by weight with respect to 100 parts by weight of the curable resin. If the content of the filler is less than 10 parts by weight, the effect of blending the filler may not be sufficiently obtained. When the content of the filler is 80 parts by weight or more, the resulting liquid crystal dropping method sealing agent may be inferior in moisture resistance. The minimum with more preferable content of the said filler is 35 weight part, and a more preferable upper limit is 65 weight part.

The sealing agent for liquid crystal dropping method of the present invention preferably further contains a silane coupling agent. The silane coupling agent mainly has a role as an adhesion aid for favorably bonding the liquid crystal dropping method sealing agent and the substrate or the like.

Although the silane coupling agent is not particularly limited, it is excellent in the effect of improving adhesiveness with a substrate and the like, and it can suppress the outflow of the curable resin into the liquid crystal by chemically bonding with the curable resin. For example, γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-isocyanatopropyltrimethoxysilane and the like are preferably used. These silane coupling agents may be used independently and 2 or more types may be used together.

The liquid crystal dropping method sealing agent of the present invention further contains other known additives such as a stress relaxation agent, a thixotropic agent, a curing accelerator, an antifoaming agent, a leveling agent, and a polymerization inhibitor, if necessary. May be.

The method for producing the sealing agent for liquid crystal dropping method of the present invention is not particularly limited, for example, a curable resin, a thermal radical polymerization initiator, and a gelling agent, a photo radical polymerization initiator, which are blended as necessary, Examples thereof include a method in which additives such as a thermosetting agent, a filler, and a silane coupling agent are mixed by a conventionally known method using three rolls and dispersed uniformly. 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.

The sealing agent for liquid crystal dropping method of the present invention is used for manufacturing a liquid crystal display element by the liquid crystal dropping method according to the above configuration, and can reduce the decrease in viscosity to a minimum even when cured by heat alone. It is possible to prevent the agent part from being inserted or the seal pattern from being broken. That is, the viscosity measured at 25 ° C. and 1.0 rpm using an E-type viscometer is 100 to 500 Pa · s, and the viscosity measured at 60 ° C. and 1.0 rpm using an E-type viscometer is 100 to 100 The viscosity measured under the conditions of 500 Pa · s and 90 ° C. and 1.0 rpm using an E-type viscometer can be 1000 Pa · s or more.

When the viscosity measured under the conditions of 25 ° C. and 1.0 rpm using the E-type viscometer of the liquid crystal dropping method of the present invention is 100 to 500 Pa · s, a fine seal pattern can be drawn using a dispenser. This is possible, and the insertion of liquid crystal can be sufficiently prevented. More preferably, the viscosity measured at 25 ° C. and 1.0 rpm using an E-type viscometer is 200 to 400 Pa · s, and more preferably 250 to 350 Pa · s.

When the viscosity measured under the conditions of 60 ° C. and 1.0 rpm using the E-type viscometer of the liquid crystal dropping method of the present invention is 100 to 500 Pa · s, a fine seal pattern can be drawn using a dispenser. It is possible, the substrates can be easily bonded together, and the insertion of liquid crystal can be sufficiently prevented. More preferably, the viscosity measured at 60 ° C. and 1.0 rpm using an E-type viscometer is 200 to 400 Pa · s, and more preferably 250 to 350 Pa · s.

Liquid crystal with increased fluidity exceeding the phase transition temperature when the viscosity measured at 90 ° C. and 1.0 rpm using the E-type viscometer of the sealing agent for liquid crystal dropping method of the present invention is 1000 Pa · s or more. Against this, it is possible to prevent the sealant part from being inserted and the seal pattern from being broken. More preferably, the viscosity measured at 90 ° C. and 1.0 rpm using an E-type viscometer is 500 Pa · s or more, and more preferably 1000 Pa · s or more.
However, in practice, it is difficult to measure the viscosity of the sealing agent for liquid crystal dropping method of the present invention at 90 ° C. where the curing reaction is proceeding. Therefore, it can be replaced by a gelation test. In the gelation test, the sealing agent is heated to 90 ° C., then immersed in an acetone solvent, and visually observed to evaluate whether or not it is insoluble in the acetone solvent. If it is insoluble in acetone solvent, the effective reaction has progressed sufficiently, and it is estimated that the viscosity measured at least at 90 ° C. and 1.0 rpm using an E-type viscometer is 1000 Pa · s or more. it can.

The sealing agent for liquid crystal dropping method of the present invention can be suitably used for the production of liquid crystal display elements by the dropping method.
The method for producing a liquid crystal display element using the sealing agent for liquid crystal dropping method of the present invention is not particularly limited. For example, the sealing agent for liquid crystal dropping method of the present invention is applied to at least one of two transparent substrates. Step 1 for forming a frame-shaped seal pattern, Step 2 for applying and dropping onto the entire surface of the frame of the seal pattern in which fine droplets of liquid crystal are formed in an uncured state of the sealant, and overlapping the other transparent substrate The method which has the process 3 which heats the combined transparent substrate and hardens a sealing compound is mentioned. When the sealing agent for liquid crystal dropping method of the present invention contains the radical photopolymerization initiator, the sealing agent is irradiated with light such as ultraviolet rays before the sealing agent is heated and cured in step 3 above. May be temporarily cured.
In addition, in the said process 1, when apply | coating the sealing compound for liquid crystal dropping methods of this invention to a transparent substrate, the sealing agent for liquid crystal dropping methods of this invention is heated in the range of 25-60 degreeC, and a sealing pattern is formed. Drawing accuracy can be improved, and the viscosity of the sealing agent for liquid crystal dropping method of the present invention at the time of forming a seal pattern is increased, so that the prevention of insertion of liquid crystal can be further enhanced. Moreover, in the said process 1, after forming a sealing pattern on a transparent substrate, the insertion prevention property of a liquid crystal can be made higher by performing a pre-curing for 1 to 10 minutes in the range of 25-60 degreeC.
The liquid crystal display element manufactured using the sealing agent for liquid crystal dropping methods of this invention is also one of this invention.

ADVANTAGE OF THE INVENTION According to this invention, the sealing agent for liquid crystal dropping methods which is excellent in adhesiveness and the prevention property of the insertion of the liquid crystal at the time of heating, and hardly causes liquid crystal contamination can be provided. Moreover, according to this invention, the liquid crystal display element manufactured using this sealing compound for liquid crystal dropping methods 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.

(Examples 1-4 Comparative Examples 1-3)
(Preparation of sealant)
Examples 1-4 by mixing each material of the compounding quantity shown in Table 1 using a planetary type stirrer (Sinky Co., Ltd., "Awatori Nertaro"), and further mixing using three rolls. The sealing agents according to Comparative Examples 1 to 3 were respectively prepared.
In Table 1, EBECRYL 3700 (manufactured by Daicel Cytec Co., Ltd., weight average molecular weight 480) is used as the bisphenol A type epoxy acrylate, and Epicron 850-S (manufactured by DIC Corporation, weight average molecular weight 340) is used as the bisphenol A type epoxy resin. F325 as a methyl acid fine particle (manufactured by Ganz Kasei), Irgacure 651 (manufactured by BASF Japan) as 2,2-dimethoxy-2-phenylacetophenone, and VPE-0201 (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymer azo compound 10-hour half-life temperature 65-70 ° C), KBM403 (manufactured by Shin-Etsu Silicone) as γ-glycidoxypropyltrimethoxysilane, SO-C1 (manufactured by Admatechs) as silica particles, and sebacic acid dihydrazide SDH (Otsuka) Company, Ltd.) were used, respectively.

(Production of liquid crystal display element)
The prepared sealant was drawn on a glass substrate with a dispenser (manufactured by Musashi Engineering, “SHOTMASTER300”) so as to draw a square frame, and precured on a hot plate at 60 ° C. for 5 minutes. Subsequently, fine droplets of TN liquid crystal (manufactured by Chisso Corporation, “JC-5001LA”) were dropped onto the frame of the seal pattern with a liquid crystal dropping device, and bonded to another glass substrate using a vacuum bonding device. . Then, it heated for 60 minutes in 120 degreeC oven, and produced the liquid crystal display element.

<Evaluation>
The following evaluation was performed about the sealing agent and liquid crystal display element which were obtained by the Example and the comparative example. The results are shown in Table 1.

(1) Viscosity of sealing agent About sealing agents obtained in Examples and Comparative Examples, conditions of 1.0 rpm at 25 ° C. and 60 ° C. using an E-type viscometer (manufactured by Brookfield, “DV-III”) The viscosity was measured at
Moreover, the gelation test was done as an alternative test of the viscosity measurement at 90 degreeC. That is, after the sealing agents obtained in Examples and Comparative Examples were heated to 90 ° C., they were immersed in an acetone solvent and visually observed to be insoluble in the acetone solvent. The case where it had been evaluated was evaluated as “×”.

(2) The applicability | paintability at the time of apply | coating the sealing agent obtained by the Example and the comparative example on the glass substrate using the applicability | distribution dispenser (The Musashi engineering company make, "SHOTMASTER300") was evaluated. When the dispensing nozzle is 400 μm, the nozzle gap is 30 μm, and the coating pressure is fixed at 300 kPa, “○” is applied when faintly applied, “△” when faint is generated, and “×” when the coating is not possible at all. ".

(3) Using a bonding dispenser (manufactured by Musashi Engineering Co., Ltd., “SHOTMASTER300”), after applying the sealing agents obtained in Examples and Comparative Examples on a glass substrate, bonding is performed using a vacuum bonding apparatus. The seal pattern was observed. Evaluation was made as “◯” when the seal was crushed and pasted, and “×” when the seal was not crushed and pasted.

(4) Insertion preventing property The shape of the seal pattern was observed for the liquid crystal display elements obtained in the examples and comparative examples. As a result, “◎” indicates that the shape of the seal pattern was not disturbed by the internal liquid crystal, “○” indicates that the shape of the seal pattern was slightly disturbed, and the shape of the seal pattern is significantly disturbed. However, the case where the liquid crystal did not break through the seal pattern was evaluated as “Δ”, and the case where the liquid crystal broke through the seal pattern and leaked to the outside was evaluated as “x”.

ADVANTAGE OF THE INVENTION According to this invention, the sealing agent for liquid crystal dropping methods which is excellent in adhesiveness and the prevention property of the insertion of the liquid crystal at the time of heating and hardly causes liquid crystal contamination can be provided. Moreover, according to this invention, the liquid crystal display element manufactured using this sealing compound for liquid crystal dropping methods can be provided.

Claims (11)

A sealing agent for a liquid crystal dropping method comprising a curable resin containing a resin having a (meth) acryloyloxy group, a thermal radical polymerization initiator, and a gelling agent. The resin having a (meth) acryloyloxy group contains an epoxy (meth) acrylate having a weight average molecular weight of 300 to 10,000, and the content of the epoxy (meth) acrylate having a weight average molecular weight of 300 to 10,000 is cured. The sealing agent for liquid crystal dropping method according to claim 1, which is 60 to 95% by weight of the total amount of the conductive resin. The curable resin contains a resin having an epoxy group having a weight average molecular weight of 100 to 8000, and the content of the resin having an epoxy group having a weight average molecular weight of 100 to 8000 is 5 to 40% of the total amount of the curable resin. The sealing agent for liquid crystal dropping method according to claim 1 or 2, wherein the content is%. The thermal radical initiator has a 10-hour half-life temperature of 40 ° C to 100 ° C, and the sealing agent for liquid crystal dropping method according to claim 1, 2, or 3. 5. The sealing agent for liquid crystal dropping method according to claim 1, wherein the content of the thermal radical initiator is 0.1 to 30 parts by weight with respect to 100 parts by weight of the curable resin. 6. The sealing agent for liquid crystal dropping method according to claim 1, wherein the gelling agent is acrylic fine particles. 7. The sealing agent for liquid crystal dropping method according to claim 1, wherein the content of the gelling agent is 1 to 40 parts by weight with respect to 100 parts by weight of the curable resin. . Furthermore, radical photopolymerization initiator is contained, The sealing compound for liquid crystal dropping methods of Claim 1, 2, 3, 4, 5, 6 or 7 characterized by the above-mentioned. Furthermore, 10 parts by weight or more and less than 80 parts by weight of filler is contained with respect to 100 parts by weight of the curable resin, and the liquid crystal dropping according to claim 1, 2, 3, 4, 5, 6, 7 or 8. Sealant for construction method. The viscosity measured at 25 ° C. and 1.0 rpm using an E-type viscometer is 100 to 500 Pa · s, and the viscosity measured at 60 ° C. and 1.0 rpm using an E-type viscometer is 100 to 500 Pa · s. s, and a viscosity measured at 90 ° C. and 1.0 rpm using an E-type viscometer is 1000 Pa · s or more, 2, 2, 3, 4, 5, 6, 7 , 8 or 9 liquid crystal dropping method sealing agent. A liquid crystal display element using the sealing agent for liquid crystal dropping method according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.