JPWO2018062164A1 - Sealant for liquid crystal display element, vertical conduction material, and liquid crystal display element - Google Patents

Abstract

An object of the present invention is to provide a sealing agent for a liquid crystal display element which is excellent in curability and stability under reduced pressure. Another object of the present invention is to provide a vertical conduction material and a liquid crystal display element formed by using the sealing agent for a liquid crystal display element.
The present invention comprises a curable resin, a maleimide compound and a radical polymerization initiator, wherein the curable resin contains a compound having a molecular weight of 500 to 1,500, and the molecular weight in 100 parts by weight of the curable resin is 500. It is a sealing agent for liquid crystal display elements whose content of the -1500 compound is 10 to 50 parts by weight.

Description

The present invention relates to a sealing agent for a liquid crystal display element which is excellent in curability and stability under reduced pressure. Further, the present invention relates to a vertical conduction material and a liquid crystal display element formed by using the sealing agent for the liquid crystal display element.

In recent years, as a method of manufacturing a liquid crystal display element such as a liquid crystal display cell or the like, a photo-thermal combination curing seal as disclosed in Patent Document 1 and Patent Document 2 from the viewpoint of shortening tact time and optimizing the amount of liquid crystal used. A liquid crystal dropping method called a dropping method using an agent is used.
In the dropping method, first, a rectangular seal pattern is formed on one of the two transparent substrates with electrodes by dispensing. Then, while the sealing agent is in an uncured state, microdroplets of liquid crystal are dropped over the entire surface of the frame of the transparent substrate, the other transparent substrate is immediately superposed, and light such as ultraviolet light is irradiated on the sealing portion 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 bonding of the substrates is performed under reduced pressure, the liquid crystal display element can be manufactured with extremely high efficiency, and the dropping method is currently the mainstream of the manufacturing method of the liquid crystal display element.

By the way, in the modern world where various liquid crystal panel-equipped mobile devices such as mobile phones and portable game machines are in widespread use, downsizing of the device is the most demanded issue. As a method of miniaturizing the device, narrowing the frame of the liquid crystal display portion is mentioned, and for example, the position of the seal portion is disposed under the black matrix (hereinafter, also referred to as narrow frame design).

However, since the sealing agent is disposed immediately below the black matrix in the narrow frame design, when the dropping method is performed, the light irradiated when the sealing agent is photocured is blocked, and the light does not reach the inside of the sealing agent. There is a problem that curing becomes insufficient. As described above, when the curing of the sealing agent is insufficient, the uncured sealing agent component is eluted into the liquid crystal, and the curing reaction by the eluted sealing agent component proceeds in the liquid crystal, thereby causing liquid crystal contamination. there were. When a curable resin having high reactivity is used to suppress liquid crystal contamination, the stability of the sealing agent is deteriorated and partially cured when the pressure is reduced at the time of bonding the substrates in the manufacturing process of the liquid crystal display device. There is a problem that the linearity of the sealing agent after bonding is impaired.

JP, 2001-133794, A WO 02/092718

An object of the present invention is to provide a sealing agent for a liquid crystal display element which is excellent in curability and stability under reduced pressure. Another object of the present invention is to provide a vertical conduction material and a liquid crystal display element formed by using the sealing agent for a liquid crystal display element.

The present invention contains a curable resin, a maleimide compound and a radical polymerization initiator, and the curable resin contains a compound having a molecular weight of 500 to 1,500, and the molecular weight is 500 in 100 parts by weight of the curable resin. It is a sealing agent for liquid crystal display elements whose content of the -1500 compound is 10 to 50 parts by weight.
The present invention will be described in detail below.

The present inventors examined improving the stability of the sealing agent under reduced pressure by using a compound having a molecular weight in a specific range as the curable resin used for the sealing agent. However, although the obtained sealing agent is excellent in stability under reduced pressure, it has a problem of being inferior in reactivity (curability). Even when the content of the compound having a specific range of molecular weight and the content of the polymerization initiator are adjusted, it is difficult to achieve both curability and stability under reduced pressure.
Then, as a result of the present inventor's earnestly examining, as a result of using a maleimide compound in addition to a curable resin while setting the content of the compound having a molecular weight of the specific range to a specific ratio, the curability and under reduced pressure The inventors have found that it is possible to obtain a sealing agent for a liquid crystal display element that is compatible with stability, and the present invention has been completed.

The sealing agent for a liquid crystal display element of the present invention contains a curable resin.
The said curable resin contains the compound of 500-1500 molecular weight. By using a compound having a molecular weight of 500 to 1,500, the sealing agent for a liquid crystal display element of the present invention is excellent in stability under reduced pressure.
The lower limit of the molecular weight of the compound having a molecular weight of 500 to 1,500 is preferably 600, the upper limit is preferably 1300, the lower limit is more preferably 700, and the upper limit is preferably 1000.
In the present specification, the above-mentioned "molecular weight" is a molecular weight determined from the structural formula for a compound whose molecular structure is specified, but for a compound having a wide distribution of polymerization degree and a compound having an unspecified modification site. , Weight average molecular weight may be used. In the present specification, the above-mentioned "weight average molecular weight" is a value determined by gel permeation chromatography (GPC) and converted to polystyrene. As a column used when measuring the weight average molecular weight by polystyrene conversion by GPC, Shodex LF-804 (made by Showa Denko) etc. are mentioned, for example.
Further, as described later, in the present invention, the maleimide compound is not included in the curable resin.

The curable resin preferably contains a (meth) acrylic compound having a molecular weight of 500 to 1,500 as the compound having a molecular weight of 500 to 1,500.
The (meth) acrylic compound having a molecular weight of 500 to 1,500 is preferably an epoxy (meth) acrylate having a molecular weight of 500 to 1,500 obtained by reacting (meth) acrylic acid with an epoxy compound. The (meth) acrylic compound having a molecular weight of 500 to 1,500 preferably has two or more (meth) acryloyl groups in one molecule in view of high reactivity.
In the present specification, the above "(meth) acrylic" means acrylic or methacrylic, and the above "(meth) acrylic compound" is an acryloyl group or methacryloyl group (hereinafter, "(meth) acryloyl group") (Also referred to as “compound”). Moreover, the above-mentioned "(meth) acrylate" means an acrylate or a methacrylate. Furthermore, the above-mentioned "epoxy (meth) acrylate" represents the compound which made all the epoxy groups in an epoxy compound react with (meth) acrylic acid.

Specific examples of the (meth) acrylic compound having a molecular weight of 500 to 1,500 include: phenol novolac epoxy (meth) acrylate, orthocresol novolac epoxy (meth) acrylate, dicyclopentadiene novolac epoxy (meth) acrylate Biphenyl novolac epoxy (meth) acrylate, naphthalenephenol novolac epoxy (meth) acrylate, bisphenol A epoxy (meth) acrylate, bisphenol F epoxy (meth) acrylate, bisphenol E epoxy (meth) acrylate, bisphenol S Epoxy (meth) acrylate, 2,2′-diallyl bisphenol A epoxy (meth) acrylate, hydrogenated bisphenol epoxy (meth) acrylate , Propylene oxide-added bisphenol A epoxy (meth) acrylate, caprolactone modified bisphenol A epoxy (meth) acrylate, resorcinol epoxy (meth) acrylate, biphenyl epoxy (meth) acrylate, sulfide epoxy (meth) acrylate, Diphenyl ether type epoxy (meth) acrylate, dicyclopentadiene type epoxy (meth) acrylate, naphthalene type epoxy (meth) acrylate, glycidyl amine type epoxy (meth) acrylate, alkyl polyol type epoxy (meth) acrylate, rubber modified epoxy (meth) And the like.

The preferable lower limit of the content of the compound having a molecular weight of 500 to 1,500 in 100 parts by weight of the curable resin is 10 parts by weight, and the preferable upper limit is 50 parts by weight. When the content of the compound having a molecular weight of 500 to 1,500 is in this range, the obtained sealing agent for a liquid crystal display element is excellent in the effect of achieving both curability and stability under reduced pressure. A more preferable lower limit of the content of the compound having a molecular weight of 500 to 1,500 is 20 parts by weight, and a more preferable upper limit is 30 parts by weight.

The said curable resin contains the other curable resin in addition to the said compound of molecular weight 500-1500. As said other curable resin, the compound whose molecular weight is less than 500 is preferable.

Examples of the compound having a molecular weight of less than 500 include (meth) acrylic compounds having a molecular weight of less than 500, and epoxy compounds having a molecular weight of less than 500.
Examples of (meth) acrylic compounds having a molecular weight of less than 500 include (meth) acrylic acid ester compounds having a molecular weight of less than 500, epoxy (meth) acrylates having a molecular weight of less than 500, and urethane (meth) acrylates having a molecular weight of less than 500 Etc. Among them, epoxy (meth) acrylates having a molecular weight of less than 500 are preferred. The (meth) acrylic compound having a molecular weight of less than 500 is preferably one having two or more (meth) acryloyl groups in one molecule because of high reactivity.

Among the (meth) acrylic acid ester compounds having a molecular weight of less than 500, monofunctional compounds are, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isodecyl (meth) acrylate, lauryl ( Meta) acrylate, isomyristyl (meth) acrylate, stearyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate 4-hydroxybutyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, bicyclopentenyl (meth) acrylate, benzyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (2-ethoxyethyl (meth) acrylate Meta) acrylate, 2-butoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, methoxyethylene glycol (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, ethyl carbitol (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, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl Hexahydrophthalic acid, 2- (meth) acryloyloxyethyl 2-hydroxypropyl phthalate, 2- (meth) acryloyloxyethyl phosphate, glycidyl (meth) acrylate and the like can be mentioned.

Among the (meth) acrylic acid ester compounds having a molecular weight of less than 500, bifunctional compounds are, for example, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate Tetraethylene glycol di (meth) acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, Neopentyl glycol di (meta Acrylate, dimethylol dicyclopentadienyl di (meth) acrylate, ethylene oxide modified isocyanuric acid di (meth) acrylate, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, carbonate diol di (meth) acrylate Etc.

Among the (meth) acrylic acid ester compounds having a molecular weight of less than 500, tri- or higher functional ones include, for example, trimethylolpropane tri (meth) acrylate, ethylene oxide-added trimethylolpropane tri (meth) acrylate, glycerin tri ( Examples include meta) acrylate, pentaerythritol tri (meth) acrylate, tris (meth) acryloyloxyethyl phosphate, pentaerythritol tetra (meth) acrylate and the like.

Examples of the epoxy (meth) acrylate having a molecular weight of less than 500 include those obtained by reacting an epoxy compound and (meth) acrylic acid in the presence of a basic catalyst according to a conventional method.

As an epoxy compound used as a raw material for synthesizing an epoxy (meth) acrylate having a molecular weight of less than 500, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol E diglycidyl ether, hydrogenated bisphenol A diglycidyl Ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol E diglycidyl ether, resorcinol diglycidyl ether, biphenyl-4,4'-diyl bis (glycidyl ether), 1,6-naphthalene diyl bis (glycidyl ether), ethylene glycol Examples include diglycidyl ether, 1,3-propanediol diglycidyl ether, 1,4-butanediol diglycidyl ether and the like.

In the urethane (meth) acrylate having a molecular weight of less than 500, for example, two equivalents of a (meth) acrylic acid derivative having a hydroxyl group per one equivalent of an isocyanate compound having two isocyanate groups in the presence of a catalytic amount of a tin compound It can be obtained by reaction.

Examples of the isocyanate compound include isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), and hydrogenation. MDI, 1, 5- naphthalene diisocyanate, norbornane diisocyanate, tolidine diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, tetramethyl xylylene diisocyanate, etc. may be mentioned.

Examples of the (meth) acrylic acid derivative having a hydroxyl group include hydroxyalkyl (meth) acrylates and mono (meth) acrylates of dihydric alcohols.
As said hydroxyalkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate etc. are mentioned, for example Be
Examples of the dihydric alcohol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol and the like.

As the epoxy compound having a molecular weight of less than 500, for example, an epoxy compound as a raw material for synthesizing an epoxy (meth) acrylate having a molecular weight of less than 500, a partial (meth) acrylic-modified epoxy resin having a molecular weight of less than 500, etc. Can be mentioned.
In the present specification, the above-mentioned partial (meth) acrylic-modified epoxy resin means a compound having one or more epoxy group and one or more (meth) acryloyl group in one molecule, for example, two or more epoxy groups Can be obtained by reacting the epoxy group of a portion of the epoxy compound having the following with (meth) acrylic acid.

The sealing agent for a liquid crystal display element of the present invention contains a maleimide compound. By using the said maleimide compound, the sealing compound for liquid crystal display elements of this invention becomes what is excellent in curability.
In the present invention, the above-mentioned maleimide compound is neither included in the curable resin nor in the radical polymerization initiator.

The above maleimide compound is preferably a polyfunctional maleimide compound having two or more maleimide groups in one molecule from the viewpoint of reactivity.

The preferred lower limit of the molecular weight of the maleimide compound is 400. When the molecular weight of the maleimide compound is 400 or more, the obtained sealing agent for a liquid crystal display element is excellent due to the effect of achieving both curability and stability under reduced pressure. A more preferable lower limit of the molecular weight of the maleimide compound is 500.
Further, from the viewpoint of reactivity, the upper limit of the molecular weight of the maleimide compound is preferably 1,500, and more preferably 1,000.

As the maleimide compound, a compound represented by the following formula (1) or a compound represented by the following formula (2) is suitably used.

In formula (1), ^{R 1} represents an alkylene group having 2 to 3 carbon atoms, n is an integer from 2 to 40.

In Formula (2), R ² represents a divalent aliphatic group having 1 to 40 carbon atoms.

In the formula (2), the number of carbon atoms in ^{R 2} is preferably 12 to 36. Further, R ² preferably has an aliphatic ring.
Specific examples of the compound represented by the above formula (2) include 1, 20-bismaleimide-10, 11-dioctyl-eicosane (compound represented by the following formula (3-1)), 1- Heptylene maleimido-2-octylene maleimido-4-octyl-5-heptylcyclohexane (compound represented by the following formula (3-2)), 1,2-dioctylene maleimido-3-octyl-4-hexyl A cyclohexane (compound represented by following formula (3-3)) etc. are mentioned. These compounds can be synthesized by the method described in US Pat. No. 5,973,166 and the like.

The preferable lower limit of the content of the maleimide compound with respect to 100 parts by weight of the curable resin is 1 part by weight, and the preferable upper limit is 10 parts by weight. When the content of the maleimide compound is in this range, the obtained sealing agent for a liquid crystal display element is excellent due to the effect of achieving both curability and stability under reduced pressure. The more preferable lower limit of the content of the maleimide compound is 3 parts by weight, and the more preferable upper limit is 8 parts by weight.

The sealing agent for a liquid crystal display element of the present invention contains a radical polymerization initiator.
As said radical polymerization initiator, a photo radical polymerization initiator and a thermal radical polymerization initiator can be used. Among these, photoradical polymerization initiators are preferred.
Further, as described above, in the present invention, the maleimide compound is not included in the above radical polymerization initiator.

Examples of the photo radical polymerization initiator include benzophenone compounds, acetophenone compounds, acyl phosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, thioxanthone and the like. Among them, oxime ester compounds are preferable.

Examples of the oxime ester compounds include 1- (4- (phenylthio) phenyl) -1,2-octanedione 2- (O-benzoyloxime), O-acetyl-1- (6- (2-methylbenzoyl) And -9-ethyl-9H-carbazol-3-yl) ethanone oxime and the like.

Among the above photo radical polymerization initiators, commercially available ones are IRGACURE OXE01, IRGACURE OXE02, IRGACURE 184, IRGACURE 369, IRGACURE 379, IRGACURE 651, IRGACURE 819, IRGACURE 907, IRGACURE 2959, Lucillin TPO (all manufactured by BASF, Inc.), benzoin methyl methyl ester Ether, benzoin ethyl ether, benzoin isopropyl ether (all are manufactured by Tokyo Chemical Industry Co., Ltd.) and the like.

As said thermal radical polymerization initiator, what consists of an azo compound, an organic peroxide, etc. is mentioned, for example. Among them, a polymeric azo initiator comprising a polymeric azo compound is preferred.
In the present specification, the above-mentioned "polymer azo compound" refers to a compound having a number average molecular weight of 300 or more which has an azo group and generates a radical capable of curing a (meth) acryloyloxy group by heat. means.

The preferable lower limit of the number average molecular weight of the above-mentioned high molecular weight azo compound is 1000, and the preferable upper limit is 300,000. When the number average molecular weight of the high molecular weight azo compound is in this range, it can be easily mixed with the curable resin while suppressing liquid crystal contamination. A more preferable lower limit of the number average molecular weight of the above-mentioned high molecular weight azo compound is 5,000, a more preferable upper limit is 100,000, a further preferable lower limit is 10,000, and a still more preferable upper limit is 90,000.
In the present specification, the above-mentioned number average molecular weight is a value determined by gel permeation chromatography (GPC) and polystyrene conversion. As a column at the time of measuring the number average molecular weight by polystyrene conversion by GPC, Shodex LF-804 (made by Showa Denko) etc. are mentioned, for example.

As said high molecular weight azo compound, what has the structure which multiple units, such as a polyalkylene oxide and polydimethylsiloxane, couple | bonded via an azo group is mentioned, for example.
As a polymeric azo compound having a structure in which a plurality of units such as a polyalkylene oxide is bonded via the above azo group, one having a polyethylene oxide structure is preferable. As such a polymeric azo compound, for example, a polycondensate of 4,4'-azobis (4-cyanopentanoic acid) and a polyalkylene glycol, or 4,4'-azobis (4-cyanopentanoic acid) and an end The polycondensate of the polydimethylsiloxane which has an amino group etc. are mentioned.
As what is marketed among the said polymeric azo compounds, VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001 (all are Wako Pure Chemical Industries Ltd. make) etc. are mentioned, for example. .
Moreover, as an azo compound which is not a polymer, V-65 and V-501 (all are Wako Pure Chemical Industries Ltd. make) etc. are mentioned, for example.

Examples of the organic peroxide include ketone peroxide, peroxy ketal, hydroperoxide, dialkyl peroxide, peroxy ester, diacyl peroxide, peroxy dicarbonate and the like.

The content of the radical polymerization initiator is preferably 0.1 parts by weight with respect to 100 parts by weight of the curable resin, and 10 parts by weight with a preferable upper limit. When the content of the radical polymerization initiator is in this range, the curability can be made superior without deteriorating the storage stability and the like of the obtained sealing agent for a liquid crystal display element. The more preferable lower limit of the content of the radical polymerization initiator is 0.5 parts by weight, and the more preferable upper limit is 5 parts by weight.

The sealing agent for a liquid crystal display element of the present invention may contain a thermosetting agent.
As said thermosetting agent, an organic acid hydrazide, an imidazole derivative, an amine compound, a polyhydric phenol type compound, an acid anhydride etc. are mentioned, for example. Among these, organic acid hydrazides are preferably used.

Examples of the organic acid hydrazide include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, malonic acid dihydrazide and the like.
Among the above organic acid hydrazides, commercially available ones are, for example, SDH, ADH (all by Otsuka Chemical Co., Ltd.), Amicure VDH, Amicure VDH-J, Amicure UDH, Amicure UDH-J (all are Ajinomoto Fine Techno Co., Ltd.) And the like.

With respect to the content of the thermosetting agent, a preferable lower limit is 1 part by weight and a preferable upper limit is 50 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the thermosetting agent is in this range, the thermosetting property can be further improved without deteriorating the coating property and the like of the obtained sealing agent for a liquid crystal display element. A more preferable upper limit of the content of the thermosetting agent is 30 parts by weight.

The sealing agent for a liquid crystal display element of the present invention improves the flexibility and adhesiveness of the cured product, and prevents the insertion of the liquid crystal into the sealing agent and the suppression of the elution of the sealing agent into the liquid crystal. It is preferred to contain soft particles.

Examples of the flexible particles include silicone particles, vinyl particles, urethane particles, fluorine particles, and nitrile particles. Among them, silicone particles and vinyl particles are preferable.

From the viewpoint of dispersibility in a resin, silicone rubber particles are preferable as the silicone particles.

As the vinyl-based particles, (meth) acrylic particles are suitably used.
The (meth) acrylic particles can be obtained by polymerizing monomers as raw materials by a known method. Specifically, for example, a method of suspension polymerization of a monomer in the presence of a radical polymerization initiator, swelling of the seed particles by causing the non-crosslinked seed particles to absorb the monomer in the presence of the radical polymerization initiator And a method of seed polymerization.

As a monomer used as the raw material for forming said (meth) acryl particle | grains, for example, alkyl (meth) acrylates, oxygen atom containing (meth) acrylates, nitrile containing monomer, fluorine containing (meth) acrylate And monofunctional monomers such as
Examples of the alkyl (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate and the like can be mentioned.
Examples of the oxygen atom-containing (meth) acrylates include 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate and the like.
As said nitrile containing monomer, (meth) acrylonitrile etc. are mentioned, for example.
The said trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, etc. are mentioned.
Among them, alkyl (meth) acrylates are preferable because the Tg of the homopolymer is low and the amount of deformation when a 1 g load is applied can be increased.

Further, in order to have a cross-linked structure, tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa ( Meta) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, ( Poly) tetramethylene di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, isocyanuric acid skeleton tri (meth) It may be used polyfunctional monomers acrylate. Among them, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, (molecular weight between crosslinking points is large, and the amount of deformation when a 1 g load is applied can be increased. Poly) tetramethylene di (meth) acrylate, 1,4-butanediol di (meth) acrylate and 1,6-hexanediol di (meth) acrylate are preferred.

The use amount of the crosslinkable monomer is preferably 1% by weight, and 90% by weight, based on the whole monomer serving as a raw material for forming the (meth) acrylic particles. When the amount of the crosslinkable monomer used is 1% by weight or more, the solvent resistance is improved, and problems such as swelling do not occur when the resin is mixed with various sealing agent materials, and the resin is easily dispersed uniformly. When the amount of the crosslinkable monomer used is 90% by weight or less, the recovery rate can be lowered. The more preferable lower limit of the amount of the crosslinkable monomer used is 3% by weight, and the more preferable upper limit is 80% by weight.

Furthermore, in addition to these acrylic monomers, styrenic monomers, vinyl ethers, carboxylic acid vinyl esters, unsaturated hydrocarbons, halogen-containing monomers, triallyl cyanurate, triallyl isocyanurate, Monomers such as triallyl trimellitate, divinyl benzene, diallyl phthalate, diallyl acrylamide, diallyl ether, γ- (meth) acryloxypropyl trimethoxysilane, and vinyl trimethoxysilane may be used.
Examples of the styrene-based monomer include styrene, α-methylstyrene, trimethoxysilylstyrene and the like.
Examples of the vinyl ethers include methyl vinyl ether, ethyl vinyl ether and propyl vinyl ether.
Examples of the carboxylic acid vinyl esters include vinyl acetate, vinyl butyrate, vinyl laurate and vinyl stearate.
Examples of the unsaturated hydrocarbon include ethylene, propylene, isoprene, butadiene and the like.
Examples of the halogen-containing monomer include vinyl chloride, vinyl fluoride, chlorostyrene and the like.

As the above (meth) acrylic particles, core-shell (meth) acrylate copolymer fine particles are also suitably used.
As what is marketed among the said core-shell (meth) acrylate copolymer microparticles | fine-particles, F351 (made by Zeon Chemical Co., Ltd.) etc. are mentioned, for example.

Further, as the vinyl-based particles, for example, polydivinylbenzene particles, polychloroprene particles, butadiene rubber particles and the like may be used.

The preferable lower limit of the average particle diameter of the flexible particles is 0.01 μm, and the preferable upper limit is 10 μm. When the average particle diameter of the above-mentioned soft particles is in this range, it becomes excellent by the effect of improving the flexibility and adhesiveness of the cured product of the obtained sealing agent for a liquid crystal display element. The more preferable lower limit of the average particle diameter of the soft particles is 0.1 μm, and the more preferable upper limit is 8 μm.
In addition, in this specification, the average particle diameter of the said flexible particle means the value obtained by measuring about the particle | grains before mix | blending to a sealing agent using a laser diffraction type particle size distribution measuring apparatus. As the laser diffraction type particle size distribution measuring apparatus, Mastersizer 2000 (manufactured by Malvern Co., Ltd.) can be used.

The preferable lower limit of the hardness of the flexible particle is 10, and the preferable upper limit is 50. When the hardness of the above-mentioned soft particles is in this range, it becomes excellent by the effect of improving the flexibility and adhesiveness of the cured product of the obtained sealing agent for a liquid crystal display element. The more preferable lower limit of the hardness of the flexible particle is 20, and the more preferable upper limit is 40.
In addition, the hardness of the said flexible particle in this specification means durometer A hardness measured by the method based on JISK6253.

The preferable lower limit of the content of the soft particles in 100 parts by weight of the sealing agent for a liquid crystal display element of the present invention is 5 parts by weight, and the preferable upper limit is 50 parts by weight. When the content of the soft particles is in this range, the effect of improving the flexibility and adhesiveness of the cured product of the obtained sealing agent for a liquid crystal display element can be improved. A more preferable lower limit of the content of the flexible particles is 10 parts by weight, and a more preferable upper limit is 30 parts by weight.

The sealing agent for a liquid crystal display element of the present invention preferably contains a filler for the purpose of improving viscosity, improving adhesion due to a stress dispersion effect, improving linear expansion coefficient, and the like.

Examples of the filler include inorganic fillers and organic fillers other than those contained in the flexible particles.
Examples of the inorganic filler include silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, smectite, bentonite, montmorillonite, sericite, activated clay, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide And calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum nitride, silicon nitride, barium sulfate, calcium silicate and the like.

The preferable lower limit of the content of the filler in 100 parts by weight of the sealant for a liquid crystal display element of the present invention is 10 parts by weight, and the preferable upper limit is 70 parts by weight. When the content of the above-mentioned filler is in this range, the effect of improving the adhesiveness and the like becomes excellent without deteriorating the coatability and the like. The more preferable lower limit of the content of the filler is 20 parts by weight, and the more preferable upper limit is 60 parts by weight.

The sealing agent for a liquid crystal display element of the present invention preferably contains a silane coupling agent. The above-mentioned silane coupling agent mainly serves as an adhesion aiding agent for favorably bonding the sealing agent and the substrate and the like.

As the above-mentioned silane coupling agent, for example, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane and the like are suitably used. These are excellent in the effect of improving the adhesion to a substrate or the like, and can suppress the outflow of the curable resin into the liquid crystal by chemically bonding with the curable resin.

The preferable lower limit of the content of the silane coupling agent in 100 parts by weight of the liquid crystal display element sealing agent of the present invention is 0.1 parts by weight, and the preferable upper limit is 10 parts by weight. When the content of the silane coupling agent is in this range, the occurrence of liquid crystal contamination is suppressed, and the adhesive property is improved. A more preferable lower limit of the content of the silane coupling agent is 0.3 parts by weight, and a more preferable upper limit is 5 parts by weight.

The sealing agent for a liquid crystal display element of the present invention may contain a light shielding agent. By containing the said light-shielding agent, the sealing compound for liquid crystal display elements of this invention can be used suitably as a light-shielding sealing compound.

Examples of the light shielding agent include titanium black, aniline black, cyanine black, fullerene, carbon black, resin-coated carbon black and the like. Moreover, iron oxide, titanium oxide, etc. mentioned as the said inorganic filler can also be used as said light-shielding agent. Among them, titanium black is preferred.

The above-mentioned titanium black is a substance whose transmittance to light in the vicinity of the ultraviolet region, particularly to light having a wavelength of 370 to 450 nm is higher than the average transmittance to light having a wavelength of 300 to 800 nm. That is, while the titanium black imparts a light shielding property to the sealing agent for a liquid crystal display element of the present invention by sufficiently shielding light having a wavelength in the visible light range, it has a property of transmitting light having a wavelength near the ultraviolet range. It is a light shielding agent. The light shielding agent contained in the sealing agent for a liquid crystal display element of the present invention is preferably a substance having a high insulating property, and titanium black is also preferable as a light shielding agent having a high insulating property.

The above-mentioned titanium black exhibits sufficient effects even if it is not surface-treated, but the surface is treated with an organic component such as a coupling agent, silicon oxide, titanium oxide, germanium oxide, aluminum oxide, oxide It is also possible to use surface-treated titanium black, such as those coated with inorganic components such as zirconium and magnesium oxide. Especially, what is processed by the organic component is preferable at the point which can improve insulation more.
In addition, a liquid crystal display device manufactured using the sealing agent for a liquid crystal display device of the present invention containing the above titanium black as a light shielding agent has a sufficient light shielding property and therefore has no light leakage and has high contrast. A liquid crystal display element having excellent image display quality can be realized.

Among commercially available titanium blacks, for example, 12S, 13M, 13M-C, 13R-N, 14M-C (all manufactured by Mitsubishi Materials Corporation), Tilac D (manufactured by Akao Kasei Co., Ltd.), etc. It can be mentioned.

The lower limit of the specific surface area of the titanium black is preferably 13 m ² / g, preferably 30 m ² / g, more preferably 15 m ² / g, and still more preferably 25 m ² / g.
The lower limit of the volume resistance of titanium black is preferably 0.5 Ω · cm, and the upper limit is preferably 3 Ω · cm. The lower limit is more preferably 1 Ω · cm, and the upper limit is preferably 2.5 Ω · cm.

The primary particle diameter of the light shielding agent is not particularly limited as long as it is equal to or less than the distance between the substrates of the liquid crystal display element, but a preferable lower limit is 1 nm and a preferable upper limit is 5000 nm. When the primary particle diameter of the light shielding agent is in this range, the light shielding property can be made superior without deteriorating the coating property and the like of the obtained sealing agent for a liquid crystal display element. The lower limit of the primary particle diameter of the light shielding agent is more preferably 5 nm, more preferably 200 nm, still more preferably 10 nm, and still more preferably 100 nm.
The primary particle diameter of the light shielding agent can be measured by dispersing the light shielding agent in a solvent (water, organic solvent, etc.) using NICOMP 380 ZLS (manufactured by PARTICLE SIZING SYSTEMS).

The preferable lower limit of the content of the light shielding agent in 100 parts by weight of the sealant for a liquid crystal display element of the present invention is 5 parts by weight, and the preferable upper limit is 80 parts by weight. When the content of the light shielding agent is in this range, it is possible to exhibit more excellent light shielding property without reducing the adhesion of the obtained sealing agent for liquid crystal display element to the substrate, the strength after curing and the drawability. it can. The lower limit of the light shielding agent content is preferably 10 parts by weight, more preferably 70 parts by weight, still more preferably 30 parts by weight, and still more preferably 60 parts by weight.

The sealant for a liquid crystal display element of the present invention further contains, as necessary, additives such as a reactive diluent, a thixotropic agent, a spacer, a curing accelerator, an antifoaming agent, a leveling agent, and a polymerization inhibitor. May be

As a method for producing the sealing agent for a liquid crystal display element of the present invention, for example, a curable resin and maleimide using a mixer such as a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, and a 3-roll mill. The method etc. which mix a compound, a radical polymerization initiator, and the silane coupling agent etc. which are added as needed are mentioned.

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. A vertical conduction material containing such a sealing agent for a liquid crystal display element of the present invention and conductive fine particles is also one of the present invention.

As said electroconductive fine particle, what formed the conductive metal layer in the surface of a metal ball and resin fine particles etc. can be used. Among them, those in which a conductive metal layer is formed on the surface of resin fine particles are preferable because the excellent elasticity of the resin fine particles allows conductive connection without damaging the transparent substrate and the like.

A liquid crystal display device using the sealing agent for a liquid crystal display device of the present invention or the vertical conduction material of the present invention is also one of the present invention.

As a method of manufacturing the liquid crystal display element of the present invention, a liquid crystal dropping method is suitably used, and specifically, for example, a method having the following respective steps can be mentioned.
First, the sealing agent for a liquid crystal display element of the present invention is applied by screen printing, dispenser coating, or the like to one of two substrates such as a glass substrate with an electrode such as ITO thin film and a polyethylene terephthalate substrate. The process of forming a pattern is performed. Next, a step of applying minute droplets of liquid crystal to the inside of the frame of the seal pattern of the substrate by a drop in a state where the sealing agent for a liquid crystal display element of the present invention is uncured is dropped, and another substrate is superposed under vacuum. After that, a liquid crystal display element can be obtained by a method of performing a step of photocuring the sealing agent by irradiating light such as ultraviolet light to the seal pattern portion of the sealing agent for liquid crystal display element of the present invention. In addition to the step of photocuring the sealing agent, the step of heating and thermally curing the sealing agent may be performed.

ADVANTAGE OF THE INVENTION According to this invention, the sealing compound for liquid crystal display elements which is excellent in curability and stability under pressure reduction can be provided. Further, according to the present invention, it is possible to provide a vertical conduction material and a liquid crystal display element formed by using the sealing agent for a liquid crystal display element.

EXAMPLES The present invention will be described in more detail by way of the following examples, but the present invention is not limited to these examples.

(Examples 1 to 9 and Comparative Examples 1 to 6)
According to the compounding ratio described in Tables 1 and 2, after mixing each material using a planetary stirrer ("Awatori Neritaro" manufactured by Shinky Co., Ltd.), mixing is further performed using three rolls. The sealing agent for liquid crystal display elements of Examples 1-9 and Comparative Examples 1-6 was prepared.
The dimaleimidoacetic ester of polytetramethylene ether glycol described in the table as a maleimide compound (manufactured by DIC, “LUMICURE MIA 200”) is a compound represented by the above formula (1).

<Evaluation>
The following evaluation was performed about each sealing compound for liquid crystal display elements obtained by the Example and the comparative example. The results are shown in Tables 1 and 2.

(Stability under reduced pressure (vacuum stability))
Each of the sealing agents for liquid crystal display elements obtained in Examples and Comparative Examples was filled in a syringe for dispensing (manufactured by Musashi Engineering, "PSY-10E"), and defoaming treatment was performed. Next, a sealing agent is applied on a glass substrate to draw a rectangular frame using a dispenser (manufactured by Musashi Engineering Co., Ltd., “SHOTMASTER 300”), and the vacuum bonding apparatus is operated for 5 minutes under a reduced pressure of 0.1 Pa. After holding, another glass substrate was bonded to obtain a cell. The inside of the vacuum bonding apparatus was returned to atmospheric pressure, the cell was taken out, and the shape of the sealing part in the cell (linearity of the sealing agent) was observed with a microscope.
The case where the minimum value of the seal width with respect to the maximum value of the seal width is 90% or more is "○", the case where it is 80% or more and less than 90% is "△", the case where it is less than 80% is "X" The stability under reduced pressure (vacuum stability) was evaluated.

(Curable)
About 5 μm of each of the sealing agents for liquid crystal display elements obtained in Examples and Comparative Examples was applied on a glass substrate, and then glass substrates of the same size were overlapped. Then, the metal halide lamp was irradiated with ultraviolet light of wavelength 365 nm at 3000 mJ / cm ² . The amount of change (reduction rate) of the (meth) acryloyl group-derived peak before and after light irradiation was measured using an infrared spectrometer (manufactured by BIORAD, “FTS 3000”).
When the reduction rate of the peak derived from (meth) acryloyl group after light irradiation is 95% or more, it is “◎”, and when it is 85% or more and less than 95%, “」 ”, 75% or more and less than 85% The case where it exists was evaluated as "(triangle | delta)", and the case where it was less than 75% was evaluated as "x".

ADVANTAGE OF THE INVENTION According to this invention, the sealing compound for liquid crystal display elements which is excellent in curability and stability under pressure reduction can be provided. Further, according to the present invention, it is possible to provide a vertical conduction material and a liquid crystal display element formed by using the sealing agent for a liquid crystal display element.

Claims (6)

Containing a curable resin, a maleimide compound and a radical polymerization initiator,
The curable resin contains a compound having a molecular weight of 500 to 1,500,
The sealing agent for a liquid crystal display element, wherein the content of the compound having a molecular weight of 500 to 1,500 in 100 parts by weight of the curable resin is 10 to 50 parts by weight. The compound for molecular weight 500-1500 is a (meth) acrylic compound with molecular weight 500-1500, The sealing compound for liquid crystal display elements of Claim 1 characterized by the above-mentioned. The sealing compound for a liquid crystal display element according to claim 1 or 2, wherein the maleimide compound is a polyfunctional maleimide compound having two or more maleimide groups in one molecule. The sealing compound for a liquid crystal display element according to claim 1, 2 or 3, wherein the maleimide compound has a molecular weight of 400 or more. A vertical conductive material comprising the sealing agent for a liquid crystal display element according to any one of claims 1, 2, 3 and 4 and conductive fine particles. A liquid crystal display device comprising the sealing agent for a liquid crystal display device according to claim 1, 2, 3 or 4 or the vertical conduction material according to claim 5.