JP2010020286A - Sealing agent for liquid crystal dropping technology and method of manufacturing liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing agent for a liquid crystal dropping technology which has high accuracy, high durability and high reliability without having an adverse effect on a liquid crystal. <P>SOLUTION: The sealing agent for the liquid crystal dropping technology used for the method of manufacturing a liquid crystal display includes a maleimide compound, an epoxy resin and a latent epoxy curing agent, does not include a photoinitiator, can be temporarily cured by irradiation with light and can be finally cured by heating after irradiation with light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a manufacturing method of a liquid crystal display device using a liquid crystal dropping method, and more particularly to a manufacturing method in which a main seal at a peripheral portion of a substrate is used using a sealant that uses both photocuring and thermal curing. Moreover, this invention relates to the sealing agent used for it.

  Conventionally, when assembling a relatively small liquid crystal display device (hereinafter also referred to as an LCD), two transparent substrates with electrodes are opposed to each other at a predetermined interval, and the periphery is sealed with a sealant. The liquid crystal was injected into the cell from a liquid crystal injection port provided in a part thereof, and the liquid crystal injection port was sealed with a sealant.

  In recent years, as large-sized LCDs have become widespread, the above-described manufacturing methods have caused various problems such as the time taken to inject liquid crystals and the poor productivity.

  Therefore, an LCD manufacturing method called a liquid crystal dropping method (ODF) is being studied and put into practical use as an efficient manufacturing method for large LCDs. In this method, first, a rectangular seal pattern is formed on one of two transparent substrates with electrodes by screen printing or the like. Next, fine droplets of liquid crystal are dropped and applied into the frame of the transparent substrate in an uncured state of the sealant, and after the other transparent substrate is overlaid, the sealant is cured to produce an LCD. If the substrates are bonded together under reduced pressure, an LCD can be manufactured efficiently.

  The sealing agent used in the liquid crystal dropping method is generally an ultraviolet curable type or an ultraviolet-heat combined curable type {Japanese Patent Laid-Open No. 2001-133794 (Patent Document 1), Japanese Patent Laid-Open No. 2006-23580 (Patent Document 2). ), JP-A-2006-23581 (Patent Document 3), JP-A-2006-23582 (Patent Document 4), etc.}. In the UV-heat combination curing type, after the two substrates are stacked, the sealant is cured in a short time to such an extent that misalignment does not occur due to UV irradiation, and further heated to heat the sealant to the final strength. Since it hardens, it is considered advantageous in terms of reliability.

  However, the ultraviolet curable and ultraviolet-heat combined curable sealant contains a photopolymerization initiator. For this reason, the residual photoinitiator that cannot be decomposed within the ultraviolet irradiation period and the decomposed product due to the ultraviolet irradiation come into contact with the liquid crystal material and adversely affect the liquid crystal. In the said patent document, when the polymerization initiator which has an acrylic group is used, it is described that a residue will decrease (for example, patent document 2, paragraphs 0022-0024). However, since it has a cleavage site by light together with an acrylic group in the molecule, it is considered that a decomposition product is necessarily generated by photocleavage.

  On the other hand, thermosetting adhesives and sealants containing maleimide compounds are known as curing systems that do not require a photopolymerization initiator (for example, WO2003 / 082940 (Patent Document 5), WO2003 / 107427). Gazette (patent document 6): Japanese translations of PCT publication No. 2005-532678 gazette).

  As an application of a composition containing a maleimide compound in a liquid crystal application, JP-A No. 2002-338946 (Patent Document 7) discloses a sealing agent containing a (meth) acrylate oligomer and a maleimide derivative, and JP-A No. 2003-34708. The gazette (patent document 8) describes a resin composition containing an epoxy resin and a maleimide-containing carboxylic acid. However, these are sealing agents for forming an empty cell having a “liquid crystal injection port”, and application to a liquid crystal dropping method is not described. Japanese Unexamined Patent Publication No. 2005-2015 (Patent Document 9) proposes a composition containing a maleimide compound having a partial structure derived from bisphenol S as a sealing agent for a liquid crystal dropping method. And patent document 9 points out the possibility that a maleimide compound and another polymeric component will elute when the sealing agent of the conventional patent document 8 is applied as a sealing agent for liquid crystal dropping methods.

  As described above, only a sealant containing a special maleimide compound is known as a light-heat combined type curable sealant suitable for a liquid crystal dropping method without requiring a photopolymerization initiator. It was.

JP 2001-133794 A JP 2006-23580 A JP 2006-23581 A JP 2006-23582 A WO2003 / 082940 WO2003 / 107427 JP 2002-338946 A JP 2003-34708 A JP-A-2005-2015

  Therefore, the present invention manufactures an LCD with high accuracy and excellent durability without adversely affecting the liquid crystal by using a light-heat combination curable resin not containing a photopolymerization curing agent when manufacturing an LCD by a liquid crystal dropping method. It aims to provide a possible method.

  The present invention relates to the following matters.

1. A sealing agent used in a method of manufacturing a liquid crystal display device by a liquid crystal dropping method,
A sealant for a liquid crystal dropping method, which contains at least a maleimide compound, does not contain a photoinitiator, can be temporarily cured by light irradiation, and can be finally cured by heating after light irradiation.

  2. 2. The sealing agent according to 1 above, further comprising an epoxy resin and a latent epoxy curing agent.

  3. 3. The sealing agent according to 1 or 2 above, further comprising an additive selected from the group consisting of a filler, a thixotropic agent and a silane coupling agent.

  4). 4. The sealing agent according to 2 or 3 above, wherein the epoxy resin contains an epoxy resin selected from the group consisting of a bisphenol type epoxy resin, a novolac type epoxy resin, and a biphenyl type epoxy resin.

  5. 5. The sealing agent according to any one of 2 to 4 above, wherein the latent epoxy curing agent is selected from organic acid dihydrazide compounds.

  6). 1 to 5 above, wherein the maleimide compound is selected from the group consisting of stearylmaleimide, oleylmaleimide, behenylmaleimide, 1,20-bismaleimide derivatives of 10,11-dioctyleicosane, and combinations thereof. The sealing agent in any one of.

7). A method of manufacturing a liquid crystal display device having a liquid crystal layer between a first substrate and a second substrate by a liquid crystal dropping method,
(A) a step of applying the sealant according to any one of 1 to 6 above to a seal region in a peripheral portion of the first substrate surface;
(B) dropping liquid crystal in a central region surrounded by the seal region on the surface of the first substrate;
(C) superimposing the second substrate on the first substrate;
(D) A temporary fixing step of irradiating the sealing agent with light; and (e) a final fixing step of heating the sealing agent.

  8). A liquid crystal display device having a liquid crystal layer between a first substrate and a second substrate and manufactured by a liquid crystal dropping method, which is sealed with a cured product of the sealing agent according to any one of 1 to 6 above. LCD device.

  By using the sealant for the liquid crystal dropping method of the present invention, it is possible to produce an LCD without adversely affecting the liquid crystal while maintaining a precise alignment accuracy without misalignment. The manufactured LCD is excellent in the durability and reliability of the seal portion.

The production method of the present invention generally comprises:
(A) a step of applying a liquid sealant to a seal region around the first substrate surface;
(B) dropping liquid crystal in a central region surrounded by the seal region on the surface of the first substrate;
(C) superimposing the second substrate on the first substrate;
(D) a temporary fixing step of irradiating the sealing agent with light; and (e) a final fixing step of heating the sealing agent.

  The first substrate and the second substrate used in the present invention are usually transparent glass substrates. Generally, transparent electrodes, active matrix elements (TFTs, etc.), alignment films, color filters, etc. are formed on at least one of the opposing surfaces of the two substrates. Is possible. The manufacturing method of the present invention is considered to be applicable to all types of LCDs.

  In the step (a), a sealant is applied in a frame shape so as to make one round of the periphery of the substrate on the periphery of one substrate, the surface of the first substrate (the surface facing the other substrate). A portion where the sealant is applied in a frame shape is referred to as a seal region. At this time, the sealant is in a liquid state that can be applied at least, and can be applied by a known method such as screen printing or dispensing.

  Next, in a process (b), a liquid crystal is dripped at the center area | region enclosed by the frame-shaped sealing area | region of the 1st board | substrate surface. This step is preferably carried out under reduced pressure.

  Next, in the step (c), the second substrate is superposed on the first substrate, and light is irradiated in the step (d). By this light irradiation, the sealing agent is temporarily cured, and the strength to such an extent that the positional deviation does not occur by handling is expressed, and the two substrates are temporarily fixed.

  The light irradiation in the step (d) is sufficient if at least the sealing agent is exposed, and it is not necessary to irradiate the entire substrate with light. In general, the irradiation time is preferably a short time, for example, 5 minutes or less, preferably 3 minutes or less, more preferably 1 minute or less.

  Next, in the step (e), when the sealing agent is heated, the sealing agent reaches the final curing strength (final curing), and the two substrates are finally fixed.

  The heat curing in step (e) is generally heated with a heating profile such that the maximum temperature is preferably up to 150 ° C, more preferably up to 130 ° C. The heating time is appropriately selected, and is, for example, 3 hours or less, preferably 2 hours or less, more preferably 1.5 hours or less (typically 1 hour). The heating device is not particularly limited, and a heating device that can store a temporarily fixed substrate can be used.

  The main part of the LCD panel is completed through the above steps.

  Next, the sealing agent used for this invention is demonstrated. The sealing agent is characterized by containing at least a maleimide compound and no photoinitiator. In a preferred embodiment of the present invention, the sealing agent further contains a thermosetting resin, particularly preferably an epoxy resin and a latent epoxy curing agent for its curing. Furthermore, a (meth) acrylate compound may be contained or may not be contained. Satisfactory characteristics can be obtained without containing a (meth) acrylate compound.

  The “photoinitiator” defined in the present invention includes general photoinitiators used for photopolymerization. Maleimide compound does not mean “photoinitiator”. In addition, general (meth) acrylate compounds that can be used as optional components in the present invention are not included in the “photoinitiator”. However, even a compound having a (meth) acrylate group (that is, a (meth) acryloyloxy group) has a partial structure capable of generating radicals by light irradiation, apart from the (meth) acrylate group. Are included in the “photoinitiator”. Specifically, a compound having a benzoin (ether) structure together with an acrylate group (acryloyloxy group) as described in, for example, JP-A-2006-23580 is a “photoinitiator”. Even in such a compound, generation of a decomposition product is presumed by cleavage at the radical generation site.

  In the present invention, the maleimide compound has a function of initiating polymerization by light irradiation, particularly ultraviolet irradiation. When the maleimide compound is itself polymerized and a (meth) acrylate compound is present, the (meth) acrylate compound is It also has a polymerization (copolymerization) function. The unreacted portion is finally cured upon heating when irradiated with light.

  The maleimide compound has a partial structure (I):

で表される部分構造を、分子中に１個以上、好ましくは１または２個有する。Ｒ^１およびＲ^２は、Ｈ、炭素数１〜６のアルキル基、またはＲ^１およびＲ^２が一緒になって炭素数２〜６のアルキレン基を表す。好ましくは、Ｒ^１およびＲ^２が共にＨ、またはＲ^１およびＲ^２が一緒になって１，４−ブチレン基を表す。

1 or more, preferably 1 or 2 in the molecule. R ¹ and R ² represent H, an alkyl group having 1 to 6 carbon atoms, or R ¹ and R ² together represent an alkylene group having 2 to 6 carbon atoms. Preferably, R ¹ and R ² are both H, or R ¹ and R ² together represent a 1,4-butylene group.

The maleimide compound used in the present invention does not contain a partial structure derived from bisphenol-S (ie, a phenyl-SO ₂ -phenyl structure).

  The maleimide compound is preferably in a liquid state at room temperature, and the group to which the partial structure (I) is bonded is a group that makes the maleimide compound in a liquid state, for example, a length and branch sufficient to make the maleimide compound into a liquid state. It is an organic group containing a branched alkyl, alkylene, alkylene oxide, alkylene carboxyl or alkylene amide structure. The maleimide compound can have one or more partial structures (I). A compound having two groups is a bismaleimide compound. Even if one maleimide compound is not liquid, it can be used as long as the sealant becomes liquid when mixed with another maleimide compound or when mixed with another component.

  Examples of maleimide compounds in which the partial structure (I) is bonded to an alkyl group or an alkylene group (these groups may include a double bond or a saturated aliphatic ring) include the following compounds. .

  Particularly preferable examples include stearyl maleimide, oleyl maleimide, behenyl maleimide, 1,20-bismaleimide derivatives of 10,11-dioctyleicosan, and combinations thereof. A 1,20-bismaleimide derivative of 10,11-dioctyleicosane is available from Henkel Corporation under the product name X-BMI, and 1,20-diamino-10,11-dioctyleicosane and / or its cyclic Synthesized from isomeric diamines according to the method described in US Pat. No. 5,973,166 (the disclosure of US Pat. No. 5,973,166 is hereby incorporated by reference). X-BMI is 1,20-bismaleimide-10,11-dioctyl-eicosane {compound represented by the formula (X-1)}, 1-heptylenemaleimide-2-octylenemaleimide-4-octyl-5 -Heptylcyclohexane {compound represented by the formula (X-2)}, 1,2-dioctylenemaleimide-3-octyl-4-hexylcyclohexane {compound represented by the formula (X-3)} or the like Includes two or more. The bismaleimide compounds represented by the formulas (X-1) to (X-3) are also preferably used alone.

  Examples of maleimide compounds in which the partial structure (I) is bonded to a group containing an alkylene oxide structure include the following compounds.

式中、Ｒは、アルキレン基であり、好ましくはエチレンまたは１，２−プロピレンであり、ｎは２〜４０程度の整数であり、好ましくはこの化合物が液状を示す程度の整数、およびｎの分布が選ばれる。この化合物は、大日本インキ化学工業（株）製ＬＵＭＩＣＵＲＥ（登録商標） ＭＩＡ２００として入手可能である。

In the formula, R is an alkylene group, preferably ethylene or 1,2-propylene, n is an integer of about 2 to 40, preferably an integer such that this compound is liquid, and distribution of n Is selected. This compound is available as LUMICURE (registered trademark) MIA200 manufactured by Dainippon Ink and Chemicals, Inc.

  Other usable maleimide compounds include the following formula:

の化合物（３，４，５，６−テトラヒドロフタロイミドエチルアクリレート（ｔｅｔｒａｈｙｄｒｏｐｈｔｈａｌｏｉｍｉｄｅｅｔｈｙｌａｃｒｙｌａｔｅ））が挙げられる。

(3,4,5,6-tetrahydrophthalimidoethyl acrylate).

  The content ratio of the maleimide compound in the sealing agent can be determined in a wide range and can be present in a ratio of 0.1 to 100% by weight of the whole sealing agent. Even in a small amount, the sealing agent can be cured (temporarily cured), and when a photocuring monomer such as a (meth) acrylate compound is contained, the ratio can generally be reduced. The content ratio of the maleimide compound is preferably 0.5% by weight or more, more preferably 1% by weight or more. Moreover, although it can harden | cure even if the content rate of a maleimide compound is 100 weight%, since a sealing agent generally contains a filler etc., it is usually less than 100 weight%. When other resins are contained, for example, when a thermosetting resin such as an epoxy resin and / or a photopolymerizable resin such as (meth) acrylate is contained, the maleimide compound is preferably contained at 90% by weight or less.

  From the viewpoint of sealing strength and the like, the sealing agent of the present invention preferably contains a thermosetting resin in addition to the maleimide compound, and particularly preferably contains an epoxy resin.

  The epoxy resin contained in the sealant is preferably composed mainly of an epoxy resin having an aromatic ring, and is 50% (weight basis) or more, preferably 70% or more, particularly preferably 90% or more of the epoxy resin component. Yes, 100% is also preferable. If necessary, an epoxy resin having no aromatic ring may be contained.

  Examples of the epoxy resin having an aromatic ring include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin; novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin. A biphenyl-type epoxy resin such as trade name YX4000 manufactured by Japan Epoxy Resin Co., Ltd. can be used. The epoxy resin having an aromatic ring usually has one or more epoxy groups in the molecule, and the epoxy equivalent can be appropriately selected.

  As an epoxy resin having no aromatic ring, an alicyclic epoxy resin having an epoxy group having a ring strain such as a cyclohexene oxide structure and a cyclopentene oxide structure in the molecule (for example, in the following formulas (1) to (5) Compounds shown)

；水素化ビスフェノール型エポキシ樹脂（ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂およびビスフェノールＳ型エポキシ樹脂等のビスフェノール型エポキシ樹脂のベンゼン環が水素化されたもの）；ジシクロペンタジエンフェノールノボラックのグリシジルエーテル等のジシクロペンタジエン型エポキシ樹脂；シクロヘキサンジメタノールジグリシジルエーテル(cyclohexanedimethanol diglycidyl ether)、ブチルグリシジルエーテル、２−エチルヘキシルグリシジルエーテル、アリルグリシジルエーテル等の脂肪族アルキル−モノまたはジ−グリシジルエーテル；グリシジルメタクリレート、３級カルボン酸グリシジルエステル等のアルキルグリシジルエステル；スチレンオキサイド；フェニルグリシジルエーテル、クレジルグリシジルエーテル、ｐ−ｓ−ブチルフェニルグリシジルエーテル、ノニルフェニルグリシジルエーテル等の芳香族アルキルモノグリシジルエーテル；テトラヒドロフルフリルアルコールグリシジルエーテル等を挙げることができる。

Hydrogenated bisphenol type epoxy resin (hydrogenated benzene ring of bisphenol type epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin); glycidyl ether of dicyclopentadienephenol novolac Dicyclopentadiene type epoxy resins such as cyclohexanedimethanol diglycidyl ether, aliphatic alkyl-mono or di-glycidyl ether such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and allyl glycidyl ether; glycidyl methacrylate; Alkyl glycidyl esters such as tertiary carboxylic acid glycidyl ester; styrene oxide; phenyl glycidyl ether, cresyl g Aromatic alkyl monoglycidyl ethers such as ricidyl ether, p-s-butylphenyl glycidyl ether, and nonylphenyl glycidyl ether; tetrahydrofurfuryl alcohol glycidyl ether and the like.

  The epoxy resin component may contain other known diluents.

  The latent epoxy curing agent used in the present invention cures the epoxy resin when heated. For latent curing agents, one or more types of commercially available latent curing agents are appropriately selected, and the addition amount of the latent curing agent should be appropriately set in consideration of the epoxy equivalent of the epoxy resin. Is preferred.

  Specifically, the latent curing agent preferably used in the present invention is preferably a heat-curing latent curing agent, such as an amine compound curing agent, a fine powder modified amine system, or a modified imidazole latent curing agent. Is mentioned. Modified amine-based and modified imidazole-based latent curing agents include core-shell type curing agents in which the surface of the core of an amine compound (or amine adducts) is surrounded by a shell of a modified amine (such as surface adduct), and the like Is included in a masterbatch type curing agent in a state of being mixed with an epoxy resin.

Examples of amine compound curing agents include aromatic primary amines such as diaminodiphenylmethane and diaminodiphenylsulfone;
2-heptadecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl-S-triazine, 1-dodecyl-2- Imidazoles such as methyl-3-benzylimidazolium chloride, 2-phenylimidazolium isocyanurate, 2-phenyl-4-methyl-5-hydroxymethylimidazole;
Boron trifluoride-amine complex;
Dicyandiamide, and derivatives of dicyandiamide such as o-tolylbiguanide and α-2,5-methylbiguanide;
Organic acid hydrazides such as carbohydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide;
Diaminomaleonitrile and its derivatives;
Mention may be made of melamine derivatives such as melamine and diallyl melamine.

  The modified amine-based latent curing agent is a finely powdered solid reaction product of an amine compound and an epoxy compound, an isocyanate compound and a urea compound. The modified imidazole-based latent curing agent is usually a fine powdered solid reaction product obtained by an adduct reaction between an imidazole compound and an epoxy resin.

  Representative examples of commercially available modified amine-based latent curing agents include, for example, “ADEKA HARDNER EH-3615S” (trademark of ADEKA Corporation), “ADEKA HARDNER EH-4070S” (trademark of ADEKA Corporation). ), “Adeka Hardener EH-4357S” (trademark of ADEKA), “Amicure MY-24” (trademark of Ajinomoto Co., Inc.), “Fujicure FXE-1000” (trademark of Fuji Kasei Kogyo Co., Ltd.), “Fujicure FXR-1036” (trademark of Fuji Kasei Kogyo Co., Ltd.), Aradur 939 (trademark of Huntsman Advanced Materials) and the like can be mentioned.

  Typical examples of commercially available modified imidazole-based latent curing agents include “ADEKA HARDNER EH-3293S” (trademark of ADEKA), ““ ADEKA HARDNER EH-4344S ”(trademark of ADEKA). , “Amicure PN-23” (trademark of Ajinomoto Co., Inc.), “Cureduct P-505” (trademark of Shikoku Kasei Kogyo Co., Ltd.), and Sanmide LH-210 (trademark of Air Products). .

  Further, the core-shell type curing agent is obtained by modifying the surface of the amine compound (or amine adducts) by further treatment with an acidic compound such as a carboxylic acid compound and a sulfonic acid compound, an isocyanate compound, and an epoxy compound. (Adduct etc.) shell is formed. In addition, the masterbatch type curing agent is a state in which a core-shell type curing agent is mixed with an epoxy resin.

  Examples of commercially available masterbatch type curing agents include “Novacure HX-3722” (trademark of Asahi Kasei Epoxy Co., Ltd.), “Novacure HX-3742” (trademark of Asahi Kasei Epoxy Co., Ltd.), “Novacure HX-3613”. (Trademark of Asahi Kasei Epoxy Co., Ltd.) and the like.

  In the present invention, organic acid dihydrazide is particularly preferable among the above latent curing agents. The organic acid dihydrazide can be appropriately selected in consideration of the melting point and the like.

  The ratio of the epoxy resin and the latent curing agent can be appropriately set depending on the type of the latent curing agent. For example, the latent curing agent is 0.5 to 500 parts by weight, preferably 100 parts by weight of the epoxy resin. Is 2 to 200 parts by weight.

  Although the content rate of an epoxy resin can be set suitably, it is 0 to 98 weight% with respect to the sealing agent total weight, for example, Preferably it is 10 to 90 weight%. The ratio of the epoxy resin to the maleimide compound is about 0 to 980 times, preferably about 0.1 to 100 times by weight.

  The sealing agent of the present invention may further contain, as an optional component, a photopolymerizable component such as a (meth) acrylate compound and / or a vinyl ether compound, but it is also very preferable not to include it.

  Specifically, as (meth) acrylate, for example, methyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, (poly) ethylene Glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, glycerin di (meth) ) Acrylate and the like. Here, “(meth) acrylate” indicates both methacrylate and acrylate as conventionally used.

  Moreover, as an acrylate compound, epoxy (meth) acrylate is also preferable, for example, epoxy (meth) acrylate derived from epoxy resin such as bisphenol A type epoxy resin or propylene glycol diglycidyl ether, and (meth) acrylic acid. Can be mentioned.

  The blending ratio of the photopolymerizable component such as the (meth) acrylate compound and / or vinyl ether compound can be appropriately set, but is preferably 90% by weight or less, more preferably 70% by weight based on the total weight of the sealing agent. % Or less. When it contains, it is preferable to make it contain at 3 weight% or more, for example. The ratio of these photopolymerizable components to the maleimide compound is 0 to 900 times, preferably 100 times or less, more preferably 20 times or less in weight ratio. When contained, it is contained in a weight ratio with respect to the maleimide compound, preferably 0.1 times or more. However, in one of the preferred embodiments of the present invention, the sealant contains a maleimide compound and preferably an epoxy resin, and does not contain any other photopolymerizable component such as a (meth) acrylate compound and / or a vinyl ether compound. Is also highly preferred.

  The sealing agent can further contain additives, resin components and the like in order to improve or change properties such as fluidity, coating properties, storage stability, curing properties, and physical properties after curing.

  Examples of components that can be contained as necessary include organic or inorganic fillers, thixotropic agents, silane coupling agents, diluents, modifiers, colorants such as pigments and dyes, surfactants, storage stabilizers, Examples include, but are not limited to, plasticizers, lubricants, antifoaming agents, and leveling agents. In particular, it is preferable to contain an additive selected from the group consisting of a filler, a thixotropic agent, and a silane coupling agent.

  The filler is not particularly limited, for example, silica, diatomaceous earth, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, barium sulfate, gypsum, calcium silicate, Examples thereof include inorganic fillers such as talc, glass beads, sericite activated clay, bentonite, aluminum nitride, and silicon nitride.

  The thixotropic agent is not particularly limited, and examples thereof include talc, fine silica, ultrafine surface-treated calcium carbonate, fine alumina, plate-like alumina; layered compounds such as montmorillonite; acicular compounds such as aluminum borate whisker. Can be mentioned. Of these, talc, fine silica, fine alumina and the like are preferable.

  The silane coupling agent is not particularly limited, but γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, SH6062, SZ6030 (above, Toray Dow Corning Silicone Co., Ltd.), KBE903, KBM803 (above, Shin-Etsu Silicone Co., Ltd.) and the like.

Sealant of the present invention obtained as described above, by light irradiation, if ultraviolet, 5000 mJ / cm ² or less, preferably can temporarily cured at 2000 mJ / cm ² or less in the irradiation energy, then heated Is finally cured. For this reason, the sealing agent of this invention is suitable for manufacture of the liquid crystal display device by a liquid crystal dropping method.

  Further, the sealing agent of the present invention is in a liquid state at an application temperature, preferably an ambient temperature (working environment temperature), and it is not always necessary that all the materials to be blended, particularly the resin material, are in a liquid state.

  As described above, since the sealing agent of the present invention does not contain a photoinitiator, there is no generation of decomposition products thereof, and therefore there is little possibility of contaminating the liquid crystal. About generation | occurrence | production of a decomposition product etc., as shown in an Example, it can evaluate by the quantity of the generated gas (outgas) from the sealing agent in hardening.

  In addition, the sealing agent used by this invention can be used conveniently for the use as which a precise assembly without a position shift is requested | required except the liquid crystal dropping method of this invention.

<Evaluation of sealing properties>
The materials shown in Table 1 were sufficiently mixed using a three-roll mill, and further 1% by weight of a 5 μm spacer was mixed to obtain sealing agents of Examples 1 to 4 and Comparative Examples 1 to 3. 2 mg of the obtained sealing agent was applied in a frame shape by a dispenser around a 2 cm × 7 cm glass substrate. About 7 mg of liquid crystal material was dropped near the center of the glass substrate and completely degassed in vacuum. Another glass substrate was overlaid and aligned. Two sealed glass substrates were placed in an ultraviolet irradiation device (100 mW / cm ² ) and irradiated with ultraviolet rays for 10 seconds. After the ultraviolet irradiation, an external force was applied to confirm whether the glass substrate was displaced or not, and whether the temporary fixing was good or bad was judged by the ultraviolet irradiation. In the examples of the present invention, a good fixing was confirmed.

  Further, the glass substrate after the ultraviolet irradiation was kept in an oven at 120 ° C. for 1 hour to complete a simulated liquid crystal cell. By visually observing the completed liquid crystal cell, the state of the liquid crystal cell (presence / absence of cracks, etc.), maintenance of the seal shape, and the like were confirmed. In the examples of the present invention, a good seal state was confirmed. The result of the sealing agent of Examples 1-4 and Comparative Examples 1-3 is put together in Table 1, and is shown.

<Evaluation of outgassing>
100 mg of the sealing agent of Examples and Comparative Examples is put in a glass bottle, covered, and irradiated with ultraviolet rays having an intensity of 100 mW / cm ² for 30 seconds, and set in a JMS-AM II 120 type gas chromatograph mass spectrometer manufactured by JEOL Ltd. And heated at 120 ° C. for 1 hour, the generated gas was automatically collected, analyzed and quantified.

  The results are shown in Table 1.

In the table:
-The numerical value of the composition is% by weight.
・ ZX-1059, manufactured by Tohto Kasei Co., Ltd., bisphenol A type and F type blended epoxy resin. ・ EP828US Japan Epoxy Resin Co., Ltd., bisphenol A type epoxy resin. Nippon Ink Chemical Co., Ltd., bismaleimide resin / Ajicure VDH-J Ajinomoto Fine-Techno Co., Inc. dihydrazide epoxy curing agent, 1,3-bis (hydrazinocarbono) Ethyl) -isopropylhydantoin / Uvacure 1561 manufactured by Cytek Surface Specialties, epoxy acrylate; bisphenol A type epoxy acrylate ester

  As is clear from Table 1, the sealing agents of the examples did not generate outgas, and had good fixation after UV irradiation and fixation after final curing. Further, as shown in Examples 1 and 2, even when no photopolymerizable component such as a (meth) acrylate resin was contained in addition to the maleimide compound, a good fixed state was obtained after UV irradiation.

  As is apparent from the above, various modifications can be made without departing from the spirit of the present invention. Therefore, the form described here is an example, and the scope of the present invention described in the claims is not limited thereto.

  By using the sealant for the liquid crystal dropping method of the present invention, it is possible to produce an LCD without adversely affecting the liquid crystal while maintaining a precise alignment accuracy without misalignment. The manufactured LCD is excellent in the durability and reliability of the seal portion. Therefore, it is useful as a sealant for an LCD manufacturing method.

Claims (8)

A sealing agent used in a method of manufacturing a liquid crystal display device by a liquid crystal dropping method,
A sealant for a liquid crystal dropping method, which contains at least a maleimide compound, does not contain a photoinitiator, can be temporarily cured by light irradiation, and can be finally cured by heating after light irradiation.   The sealing agent according to claim 1, further comprising an epoxy resin and a latent epoxy curing agent.   The sealant according to claim 1 or 2, further comprising an additive selected from the group consisting of a filler, a thixotropic agent, and a silane coupling agent.   The sealing agent according to claim 2 or 3, wherein the epoxy resin contains an epoxy resin selected from the group consisting of a bisphenol type epoxy resin, a novolac type epoxy resin, and a biphenyl type epoxy resin.   The sealing agent according to claim 2, wherein the latent epoxy curing agent is selected from organic acid dihydrazide compounds.   The maleimide compound is selected from the group consisting of stearyl maleimide, oleyl maleimide, behenyl maleimide, 1,11-dioctyleicosane 1,20-bismaleimide derivatives, and combinations thereof. The sealing agent according to any one of 5. A method of manufacturing a liquid crystal display device having a liquid crystal layer between a first substrate and a second substrate by a liquid crystal dropping method,
(A) a step of applying the sealant according to any one of claims 1 to 6 to a seal region in a peripheral portion of the first substrate surface;
(B) dropping liquid crystal in a central region surrounded by the seal region on the surface of the first substrate;
(C) superimposing the second substrate on the first substrate;
(D) A temporary fixing step of irradiating the sealing agent with light; and (e) a final fixing step of heating the sealing agent.   It is a liquid crystal display device which has a liquid crystal layer between the 1st substrate and the 2nd substrate, and was manufactured by the liquid crystal dropping construction method, Comprising: It seals with the hardened material of the sealing agent in any one of Claims 1-6 Liquid crystal display device.