JP2005015758A - Curable resin composition, sealing agent for liquid crystal display element, encapsulating agent for liquid crystal display element, vertical conduction material for liquid crystal display element, and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable resin composition which provide a liquid crystal display element which, when used as at least one of a liquid crystal display element sealing agent, a liquid crystal display element encapsulating agent and a liquid crystal display element vertical conduction material, releases no polymerization initiator into the liquid crystal material before curing, prevents a remaining polymerization initiator from being heated to outgas with the liquid crystal rearranged after curing, is excellent in low voltage drivability, high contrast and brightness, and has large resistance and high voltage retention; a liquid crystal display element sealing agent; a liquid crystal display element encapsulating agent; a liquid crystal display element vertical conduction material; and a liquid crystal display element. <P>SOLUTION: The curable resin composition comprises a radical polymerization initiator which has a radical polymerization initiating group, a hydrogen bonding functional group, and two or more reactive functional groups in the molecule, wherein the radical polymerization initiating group is irradiated with light and/or heat to dissociate it into two active radical species. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a liquid crystal display when uncured, particularly when used as at least one of a sealing agent for liquid crystal display elements, a sealing agent for liquid crystal display elements, and a vertical conduction material for liquid crystal display elements in the production of liquid crystal display elements by a dropping method. Even when it comes into contact, the polymerization initiator does not elute into the liquid crystal material, and the residue of the polymerization initiator after curing does not become outgassing due to heating during liquid crystal realignment, low voltage driveability, Curable resin composition, liquid crystal display element sealing agent, liquid crystal display element sealing agent, liquid crystal display element upper and lower parts for obtaining a liquid crystal display element excellent in high contrast, brightness, etc., and having high resistance and high voltage holding ratio The present invention relates to a conductive material and a liquid crystal display element using these.

  In recent years, electronic devices, electronic components, and the like are increasingly required to have high performance and high quality, and among them, development of liquid crystal panels as display devices is actively performed. As a method for producing a liquid crystal display element such as a liquid crystal panel, conventionally, two transparent substrates with electrodes are opposed to each other at a predetermined interval, and the periphery is sealed with a sealing agent to form a cell. A method of injecting liquid crystal into a cell from a liquid crystal injection port provided in the part and sealing with a sealing agent is performed. In recent years, attention has been paid to a dropping method in which a sealant is applied to the periphery of an image display area of a cell substrate to form a frame pattern, and a liquid crystal is dropped into the frame pattern and then the substrate is bonded.

  In recent development of liquid crystal panels, there is a tendency to use liquid crystal with a low driving voltage (low voltage type liquid crystal) due to low power consumption for mobile use. This low voltage type liquid crystal has a problem that it has a large dielectric anisotropy, so that impurities can be easily taken in, and the orientation of the liquid crystal is disturbed and the voltage holding ratio of the liquid crystal display element is lowered.

  Examples of such impurities include a polymerization initiator blended in the sealant as an active radical generator. Since a low molecular organic compound has been used as a polymerization initiator blended in a conventional sealant, for example, when an uncured sealant comes into contact with liquid crystal when a liquid crystal display element is produced by a dropping method, the polymerization initiator is liquid crystal May be eluted. In addition, since a residue derived from the polymerization initiator remains even after the polymerization is completed, the residue is eluted in the liquid crystal, or becomes an outgas by heating at the time of realignment of the liquid crystal. There has been a problem that it may cause a decrease and gap unevenness. In addition, when the curable resin composition similar to that of the sealing agent is used as the vertical conduction material, there is a problem similar to that of the sealing agent.

  In contrast, Patent Document 1 discloses a transparent polymer substance obtained by polymerizing a transparent polymer substance-forming material containing a photopolymerizable composition and a photopolymerization initiator having a (meth) acryloyloxy group. However, a liquid crystal device supported between two transparent substrates is disclosed. Since this liquid crystal device does not use a low molecular weight polymerization initiator, the residue of the polymerization initiator after the polymerization is difficult to elute into the liquid crystal, which causes display defects such as disordered alignment of the liquid crystal and color unevenness. The problem has been improved to some extent. However, in addition to incomplete prevention of dissolution of the residue into the liquid crystal, the polymerization initiator elutes into the liquid crystal when it comes into contact with the liquid crystal when uncured by a dropping method or the like, and the residue of the polymerization initiator after curing The problem that the body is outgassed by heating during liquid crystal realignment has not been solved.

JP-A-5-264980

  In view of the above-mentioned present situation, the present invention, particularly when used as at least one of a liquid crystal display element sealing agent, a liquid crystal display element sealing agent and a liquid crystal display element vertical conduction material in the production of a liquid crystal display element by a dropping method, Even when it is in contact with the liquid crystal when uncured, the polymerization initiator does not elute into the liquid crystal material, and the residue of the polymerization initiator after curing does not become outgassing due to heating during liquid crystal realignment, A curable resin composition, a liquid crystal display element sealing agent, a liquid crystal display element sealing agent, which is excellent in low-voltage drivability, high contrast, brightness, etc., and has a high resistance and a high voltage holding ratio, a liquid crystal display element sealing agent, It is an object of the present invention to provide a vertical conduction material for a liquid crystal display element and a liquid crystal display element using these materials.

The present invention has a radical polymerization initiating group that dissociates into two active radical species upon irradiation with light and / or heat, a hydrogen-bonding functional group, and two or more reactive functional groups in one molecule. It is a curable resin composition containing a radical polymerization initiator.
The present invention is described in detail below.

The curable resin composition of the present invention contains a radical polymerization initiator having a radical polymerization initiating group, a hydrogen bonding functional group and a reactive functional group in one molecule.
In the radical polymerization initiator, the radical polymerization initiating group means a functional group that is dissociated into two active radical species by light and / or heat to initiate a radical polymerization reaction. Among these, a radical polymerization initiator having a radical polymerization initiating group that dissociates into two active radical species by light is preferable because it can be suitably used for the dropping method. Examples of such radical polymerization initiating groups include a carbonyl group, a sulfur-containing group, an azo group, an organic peroxide-containing group, and the like. Among these, the following general formulas (1) to (6) are represented. A group having a structure is preferred.

In the general formula (1) ~ (6), R 1, R 2 and R ³ in each independently, an alkyl group having 1 to 6 carbon atoms, a hydrogen atom, a hydroxyl group, an alkoxyl group having 1 to 6 carbon atoms , (Meth) acrylic group, phenyl group, R ⁴ , R ⁵ , R ⁶ and R ⁷ are cyano group, alkyl group having 1 to 6 carbon atoms, hydrogen atom, hydroxyl group, alkoxyl having 1 to 6 carbon atoms Represents an aromatic ring which may have a group, a (meth) acryl group, an alkyl group having 1 to 6 carbon atoms or a halogen group;

  Represents an aromatic ring which may have an alkyl group having 1 to 6 carbon atoms or a halogen group.

  Among these, groups having a structure represented by the above general formulas (1) to (4) that absorb relatively weak light and dissociate into active radical species are more preferable. From the viewpoint of the generation efficiency of active radicals, the above general formula is preferable. A group having the structure represented by (1) is more preferred.

The hydrogen bonding functional group is not particularly limited as long as it is a functional group or a residue having hydrogen bonding properties, for example, OH group, NH ₂ group, NHR group (R is an aromatic or aliphatic hydrocarbon) And COOH groups, CONH ₂ groups, NHOH groups, and the like, and groups having residues such as NHCO bonds, NH bonds, CONHCO bonds, and NH—NH bonds in the molecule.
When the radical polymerization initiator has such a hydrogen bonding functional group, the radical polymerization initiator is less likely to elute even when the uncured curable resin composition of the present invention is in contact with the liquid crystal. Liquid crystal contamination is less likely to occur.

  The radical polymerization initiator contains two or more hydrogen bonding functional groups in one molecule. Moreover, it is preferable that both of the two active radical species generated by dissociation of radical polymerization initiating groups by irradiation with light and / or heat have at least one hydrogen bonding functional group. That is, when the radical polymerization initiating group is dissociated by light and / or heat to generate two active radical species, any of the active radical species is at least one hydrogen bondable functional group. It is preferable that it is arrange | positioned in a molecule | numerator so that it may have. As a result, even when all the active radical species generated are in contact with the liquid crystal, the components of the polymerization initiator are less likely to elute in the liquid crystal, and liquid crystal contamination is less likely to occur.

The reactive functional group is not particularly limited as long as it is a functional group that can be bonded to the curable resin described later by a polymerization reaction. For example, a cyclic ether group such as an epoxy group or an oxetanyl group, a (meth) acryl group, or a styryl group. Etc. Of these, a (meth) acryl group or an epoxy group is preferred.
By having such a reactive functional group in the molecule, the radical polymerization initiator itself is fixed by forming a copolymer with the curable resin. Is not eluted into the liquid crystal, and is not outgassed by heating during liquid crystal realignment.

The radical polymerization initiator contains two or more of the reactive functional groups in one molecule. Of the two or more reactive functional groups, at least one is preferably a (meth) acryl group, and at least one is preferably a cyclic ether group.
Moreover, it is preferable that both of two active radical species produced by dissociation of radical polymerization initiating groups by irradiation with light and / or heat have at least one reactive functional group. That is, the reactive functional group has at least one reactive functional group when the radical polymerization initiating group is dissociated by light and / or heat to generate two active radical species. It is preferable that they are arranged in the molecule. Thereby, since all the generated active radical species are fixed by forming a copolymer with the curable resin, the residue of the polymerization initiator does not elute into the liquid crystal even after the completion of the polymerization, There is no outgassing due to heating during liquid crystal realignment.

  The lower limit of the number average molecular weight of the radical polymerization initiator is preferably 300. If it is less than 300, the radical polymerization initiator component may elute into the liquid crystal, and the orientation of the liquid crystal may be easily disturbed. A preferable upper limit is 3000. If it exceeds 3000, it may be difficult to adjust the viscosity of the curable resin composition of the present invention.

  It does not specifically limit as a manufacturing method of the said radical polymerization initiator, A conventionally well-known method can be used, for example, the said radical polymerization initiating group and hydroxyl group using (meth) acrylic acid or (meth) acrylic acid chloride. And (meth) acrylic esterification of an alcohol derivative having two or more in the molecule; a compound having two or more radical polymerization initiating groups and a hydroxyl group or an amino group in the molecule; A method of reacting one or more epoxy groups of a compound having two or more; one of the compound having two or more radical polymerization initiating groups and a hydroxyl group or amino group in the molecule, and one of compounds having two or more epoxy groups in the molecule (Meth) acrylic acid monoester having (meth) acrylic acid or an active hydrogen group. A method of reacting with a styrene monomer or the like; reacting a compound having two or more radical polymerization initiating groups and a hydroxyl group or an amino group in the molecule with a cyclic ester compound or a carboxylic acid compound having a hydroxyl group; A method of converting the hydroxyl group into a (meth) acrylic ester; a urethane derivative is synthesized from a compound having two or more radical polymerization initiating groups and a hydroxyl group or an amino group in the molecule, and a bifunctional isocyanate derivative; And (meth) acrylic acid, glycidol, (meth) acrylic acid ester monomer having a hydroxyl group, styrene monomer and the like.

Examples of the compound having two or more epoxy groups in the molecule include a bifunctional epoxy resin compound.
The bifunctional epoxy resin compound is not particularly limited. For example, a bisphenol A type epoxy compound, a bisphenol F type epoxy resin, a bisphenol AD type epoxy resin, an epoxy resin obtained by adding these to water, a novolac type epoxy resin, a urethane-modified epoxy Examples thereof include a resin, a nitrogen-containing epoxy resin obtained by epoxidizing meta-xylenediamine and the like, a rubber-modified epoxy resin containing polybutadiene or nitrile butadiene rubber (NBR), and the like. These bifunctional epoxy resin compounds may be solid or liquid.

  The (meth) acrylic acid ester monomer having a hydroxyl group is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. And mono (meth) acrylates of trivalent alcohols such as mono (meth) acrylates of trihydric alcohols, trimethylolethane, trimethylolpropane and glycerin, and di (meth) acrylates. These may be used independently and 2 or more types may be used together.

  Examples of the bifunctional isocyanate derivative include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), xylene diisocyanate (XDI), isophorone diisocyanate (IPDI), naphthylene diisocyanate (NDI), tolidine diisocyanate (TPDI), hexamethylene. Examples include diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), trimethylhexamethylene diisocyanate (TMHDI), and the like.

  A preferable lower limit of the blending amount of the radical polymerization initiator in the curable resin composition of the present invention is 0.1 part by weight with respect to 100 parts by weight of the curable resin described later, and a preferable upper limit is 15 parts by weight. If it is less than 0.1 part by weight, the curable resin composition of the present invention may not be sufficiently cured, and if it exceeds 15 parts by weight, the storage stability may be lowered. A more preferred lower limit is 1 part by weight, and a more preferred upper limit is 7 parts by weight.

The curable resin composition of the present invention contains a curable resin.
Examples of the curable resin include (meth) acrylic acid esters, ethylene derivatives, styrene derivatives, and epoxy resins. Of these, (meth) acrylic acid esters and epoxy resins are preferred from the viewpoint that the reaction proceeds promptly and the adhesiveness is good.

The curable resin preferably has a hydrogen bonding functional group in the molecule. As a result, the radical polymerization initiator is fixed to the curable resin by hydrogen bonding, so that the radical polymerization initiator flows into the liquid crystal even when the uncured curable resin composition touches the liquid crystal in a dropping method or the like. And no contamination. Although it does not specifically limit as said hydrogen bondable functional group, A hydroxyl group or a urethane group is preferable.
The curable resin preferably has 2 or more addition-reactive functional groups in the molecule, and more preferably 2 or more and 4 or less. Thereby, the residual amount of the unreacted resin after curing can be reduced, and the unreacted resin can be prevented from contaminating the liquid crystal.

  Examples of the (meth) acrylic acid ester include urethane (meth) acrylate having a urethane bond, epoxy (meth) acrylate derived from a compound having a glycidyl group and (meth) acrylic acid, three per molecule. Examples thereof include (meth) acrylates derived from the above polyols containing OH groups, polyester polyols and (meth) acrylic acid in a state in which one or more OH groups are left.

  Examples of the urethane (meth) acrylate include derivatives of a diisocyanate such as isophorone diisocyanate and a reactive compound that undergoes an addition reaction with an isocyanate such as acrylic acid or hydroxyethyl acrylate. These derivatives may be chain-extended with caprolactone or polyol. Examples of commercially available products include U-122P, U-340P, U-4HA, U-1084A (all manufactured by Shin-Nakamura Chemical Co., Ltd.), KRM7595, KRM7610, KRM7619 (all manufactured by Daicel UCB). It is done.

  Examples of the epoxy (meth) acrylate include epoxy (meth) acrylate derived from an epoxy resin such as bisphenol A type epoxy resin or propylene glycol diglycidyl ether and (meth) acrylic acid. Examples of commercially available products include EA-1020, EA-6320, EA-5520 (all manufactured by Shin-Nakamura Chemical Co., Ltd.), epoxy ester 70PA, epoxy ester 3002A (all manufactured by Kyoeisha Chemical Co., Ltd.), and the like. .

  Examples of (meth) acrylates derived from a polyol or polyester polyol containing three or more OH groups in one molecule and (meth) acrylic acid leaving one or more OH groups include, for example, methyl methacrylate, Tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, (poly) ethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylol Examples include propane triacrylate, pentaerythritol triacrylate, glycerin dimethacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, and the like.

  It does not specifically limit as said epoxy resin, For example, (meth) acrylic acid modified epoxy resin, urethane modified (meth) acrylic epoxy resin, etc. are mentioned.

  Examples of the (meth) acrylic acid-modified epoxy resin include novolak type epoxy resin, bisphenol type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, tris (hydroxyphenyl) alkyl type epoxy resin, and tetrakis (hydroxyphenyl) alkyl. And a partially (meth) acrylated type epoxy resin, cycloaliphatic epoxy resin and the like. Of these, a partially (meth) acrylated novolac type epoxy resin is preferable. This is because by using a novolac type epoxy resin as the base resin, the storage stability of the sealant of the present invention is further improved as compared with a linear bisphenol type epoxy resin.

  The raw material epoxy resin of the (meth) acrylic acid-modified epoxy resin includes, for example, phenol novolak type, cresol novolak type, biphenyl novolak type, trisphenol novolak type, dicyclopentadiene novolak type and the like as bisphenol. Examples of the type include bisphenol A type, bisphenol F type, 2,2′-diallyl bisphenol A type, hydrogenated bisphenol type, polyoxypropylene bisphenol A type cyclic aliphatic epoxy, and the like. These may be used alone or in combination of two or more.

As the above bisphenol A type epoxy resin, for example, Epicoat 828, Epicoat 834, Epicoat 1001, Epicoat 1004 (all manufactured by Japan Epoxy Resin Co., Ltd.), Epicron 850, Epicron 860, Epicron 4055 ( All of them are manufactured by Dainippon Ink & Chemicals, Inc.), and examples of the bisphenol F type epoxy resin include Epicoat 807 (manufactured by Japan Epoxy Resin Co., Ltd.), Epicron 830 (manufactured by Dainippon Ink & Chemicals, Inc.) and the like. Examples of the phenol novolac type epoxy resin include Epicron N-740, N-770, N-775 (manufactured by Dainippon Ink and Chemicals), Epicoat 152, 154 (manufactured by Japan Epoxy Resin). , Above As the sol novolak type, for example, Epicron N-660, N-665, N-670, N-673, N-680, N-695, N-665-EXP, N-672-EXP (Dainippon Ink Chemical Co., Ltd.) Etc.).
Examples of the cycloaliphatic epoxy resin include Celoxide 2021, Celoxide 2080, Celoxide 3000 (all manufactured by Daicel UBC), etc. Examples thereof include those obtained by reacting an epoxy resin and (meth) acrylic acid in the presence of a basic catalyst according to a conventional method.

  By appropriately changing the blending amount of the epoxy resin and the blending amount of (meth) acrylic acid, an epoxy resin having a desired acrylate ratio can be obtained. Specifically, the preferred lower limit of the carboxylic acid relative to 1 equivalent of epoxy group is 0.1 equivalent, the preferred upper limit is 0.5 equivalent, the more preferred lower limit is 0.2 equivalent, and the more preferred upper limit is 0.4 equivalent. .

As the urethane-modified (meth) acrylic epoxy resin, for example, a polyol and a bifunctional or higher isocyanate are reacted, and a (meth) acrylic monomer having a hydroxyl group and glycidol are further reacted with this, and a polyol is not used. Examples thereof include those obtained by reacting a bifunctional or higher isocyanate with a hydroxyl group-containing (meth) acrylic monomer or glycidol, and further, those obtained by reacting an isocyanate group-containing (meth) acrylate monomer with glycidol.
Specifically, for example, first, 1 mol of trimethylolpropane and 3 mol of isophorone diisocyanate are reacted under a tin-based catalyst. It is obtained by reacting an isocyanate group remaining in the obtained compound with hydroxyethyl acrylate which is an acrylic monomer having a hydroxyl group and glycidol which is an epoxy having a hydroxyl group.

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

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

  The (meth) acrylic acid ester monomer having a hydroxyl group is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. Mono (meth) acrylates of dihydric alcohols such as mono (meth) acrylates of trivalent alcohols such as trimethylolethane, trimethylolpropane, glycerin, epoxy acrylates such as di (meth) acrylates, bisphenol A modified epoxy acrylates, etc. Is mentioned. These may be used independently and 2 or more types may be used together.

The curable resin composition of the present invention may further contain a curing agent.
The curing agent is for reacting and crosslinking the epoxy group in the curable resin by heating, and can improve the adhesiveness and moisture resistance of the cured product. It is possible to suppress the deterioration of characteristics.
Such a curing agent is not particularly limited, and examples thereof include metaphenylenediamine, diaminodiphenylmethane, dicyandiamide, guanidine derivatives, and imidazole derivatives such as methylethylimidazole. These curing agents may be used alone or in combination of two or more.

  The preferable lower limit of the amount of the curing agent in the curable resin composition of the present invention is 1 part by weight with respect to 100 parts by weight of the curable resin, and the preferable upper limit is 50 parts by weight. If it is less than 1 part by weight, the curability of the curable resin composition of the present invention may be insufficient, and if it exceeds 50 parts by weight, the storage stability may be deteriorated. A more preferred lower limit is 5 parts by weight, and a more preferred upper limit is 40 parts by weight.

The curable resin composition of the present invention may further contain a silane coupling agent. The silane coupling agent has a role as an adhesion aid that improves adhesion to a glass substrate or the like.
Although it does not specifically limit as said silane coupling agent, Since it is excellent in the adhesive improvement effect with a glass substrate etc., and it can prevent the outflow in a liquid crystal by chemically bonding with curable resin, for example, (gamma) -amino Propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-isocyanatopropyltrimethoxysilane, etc., and a structure in which the imidazole skeleton and alkoxysilyl group are bonded via a spacer group What consists of the imidazole silane compound which has is used suitably. These silane coupling agents may be used alone or in combination of two or more.

  The minimum with the preferable compounding quantity of the said coupling agent in the curable resin composition of this invention is 0.1 weight part with respect to 100 weight part of the said curable resin, and a preferable upper limit is 4 weight part. If the amount is less than 0.1 part by weight, the effect of blending the coupling agent may not be sufficiently exerted. If the amount exceeds 4 parts by weight, the excess coupling agent will flow out into the liquid crystal and adversely affect the orientation of the liquid crystal. May give.

  The curable resin composition of the present invention may contain a filler for the purpose of improving the adhesiveness due to the stress dispersion effect and improving the linear expansion coefficient. The filler is not particularly limited, and examples thereof include silica particles, alumina, talc and the like.

  The curable resin composition of the present invention further includes a reactive diluent for adjusting viscosity, a thixotropic agent for adjusting thixotropy, a spacer such as polymer beads for adjusting panel gap, It may contain a curing accelerator such as P-chlorophenyl-1,1-dimethylurea, an antifoaming agent, a leveling agent, a polymerization inhibitor, and other additives.

The curable resin composition of the present invention preferably has a volume resistivity of 1 × 10 ¹³ Ω · cm and a dielectric constant of 3 or more at 100 kHz. When the volume resistance value is less than 1 × 10 ¹³ Ω · cm, it means that the curable resin composition of the present invention contains an ionic impurity, and the liquid crystal display element sealant and the liquid crystal display element use When used as a sealing agent or a vertical conduction material for a liquid crystal display element, ionic impurities are eluted into the liquid crystal when energized, which affects the liquid crystal driving voltage and may cause display unevenness. In addition, the dielectric constant of the liquid crystal is usually about ε // (parallel) is about 10 and ε⊥ (vertical) is about 3.5. Therefore, when the dielectric constant is less than 3, the curable resin composition is in the liquid crystal. May affect the liquid crystal driving voltage and cause display unevenness.

  The method for producing the curable resin composition of the present invention is not particularly limited. For example, the curable resin, the radical polymerization initiator, and additives that are blended as necessary are mixed by a conventionally known method. Methods and the like. 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 curable resin composition of the present invention comprises a radical polymerization initiating group dissociated into two active radical species by light and / or heat, a hydrogen bonding functional group, and two or more reactive functional groups in one molecule. Since it contains a radical polymerization initiator in the liquid crystal display element sealing agent, liquid crystal display element sealing agent, or liquid crystal display element vertical conduction material, the liquid crystal is in an uncured state in a dropping method or the like. Even when touched, the polymerization initiator does not flow out into the liquid crystal and become contaminated. In addition, the residue of the polymerization initiator after polymerization is not eluted into the liquid crystal, and the liquid crystal display element does not have the problem of occurrence of display defects such as disordered alignment of liquid crystal and color unevenness. Furthermore, since the residue of the polymerization initiator after curing does not become outgassing by heating at the time of liquid crystal realignment, the adhesive force between the glass substrates is not reduced and gap unevenness does not occur.
Therefore, a liquid crystal display element obtained by using at least one of a sealing agent for liquid crystal display elements, a sealing agent for liquid crystal display elements, and a vertical conduction material for liquid crystal display elements comprising the curable resin composition of the present invention is reliable. Therefore, it can be suitably used as a display panel for characters and symbols of office equipment, home appliances, automobile meters and the like.
The sealing agent for liquid crystal display elements or the sealing agent for liquid crystal display elements comprising the curable resin composition of the present invention is also one aspect of the present invention.

Further, in the liquid crystal display element, in general, a vertical conduction material is used in order to make vertical conduction between opposing electrodes on two transparent substrates. The vertical conduction material is usually configured by containing conductive fine particles in a curable resin composition.
The vertical conduction material for a liquid crystal display element comprising the curable resin composition of the present invention and conductive fine particles is also one aspect of the present invention.

  The conductive fine particles are not particularly limited. For example, metal fine particles; those obtained by subjecting resin substrate fine particles to metal plating (hereinafter referred to as metal plating fine particles); Those coated (hereinafter referred to as coated metal plated fine particles); and those metal fine particles, metal plated fine particles, and coated metal plated fine particles having protrusions on the surface. Especially, since it is excellent in the uniform dispersibility in a resin composition and electroconductivity, the metal plating fine particle and covering metal plating fine particle which gave gold plating are preferable.

  The minimum with the preferable compounding quantity with respect to 100 weight part of the said curable resin composition of the said electroconductive fine particles is 0.2 weight part, and a preferable upper limit is 5 weight part.

  The method for producing the vertical conduction material for a liquid crystal display element of the present invention is not particularly limited. For example, the curable resin composition, the conductive fine particles and the like are blended so as to have a predetermined blending amount, and a vacuum planetary type is used. The method of mixing with a stirring apparatus etc. is mentioned.

The method for producing a liquid crystal display element using at least one of the sealing agent for liquid crystal display elements of the present invention, the sealing agent for liquid crystal display elements of the present invention, and the vertical conduction material for liquid crystal display elements of the present invention is particularly limited. For example, it can be manufactured by the following method.
First, the sealing agent for liquid crystal display elements of the present invention is applied to one of two transparent substrates with electrodes such as an ITO thin film so as to have a predetermined pattern in which the liquid crystal inlet is released. Examples of the application method include screen printing and dispenser application. Furthermore, the vertical conduction material for a liquid crystal display element of the present invention is applied onto a predetermined electrode on the other transparent substrate. Examples of the application method include screen printing and dispenser application. Instead of using a vertical conduction material, it is possible to incorporate conductive fine particles in the sealant to achieve vertical conduction. Next, the two transparent substrates are opposed to each other via a spacer, and are overlapped while aligning. Thereafter, the seal portion and the vertical conduction material portion of the transparent substrate are cured by irradiating with ultraviolet rays. When the sealing agent for liquid crystal display elements of the present invention and the vertical conduction material for liquid crystal display elements of the present invention have thermosetting properties, they are further cured by heating in an oven at 100 to 200 ° C. for 1 hour to complete the curing. Finally, liquid crystal is injected from the liquid crystal injection port, and the injection port is closed using the sealing agent for liquid crystal display element of the present invention to produce a liquid crystal display element.

  Moreover, as a manufacturing method of the liquid crystal display element by a dripping method, for example, the liquid crystal display element sealant of the present invention is formed into a rectangular shape on one of two transparent substrates with electrodes such as an ITO thin film by screen printing, dispenser application, or the like. The seal pattern is formed. Further, a vertical conduction pattern is formed on a predetermined electrode on the other transparent substrate by screen printing, dispenser application or the like of the vertical conduction material for a liquid crystal display element of the present invention. Instead of using a vertical conduction material, it is possible to incorporate conductive fine particles in the sealant to achieve vertical conduction. Next, a liquid crystal micro-droplet is dropped onto the entire surface of the transparent substrate frame in an uncured state of the sealant, and the other transparent substrate is immediately overlapped in an uncured state of the vertically conductive material, and the seal portion and the vertically conductive material portion The material is cured by irradiating it with ultraviolet rays. When the sealing agent for liquid crystal display elements of the present invention and the vertical conduction material for liquid crystal display elements of the present invention have thermosetting properties, the curing is further completed by heating and curing in an oven at 100 to 200 ° C. for 1 hour, A liquid crystal display element is produced.

  The liquid crystal display element using at least one of the sealing agent for liquid crystal display elements of the present invention, the sealing agent for liquid crystal display elements of the present invention, and the vertical conduction material for liquid crystal display elements of the present invention is also one aspect of the present invention. It is.

  The liquid crystal display element of the present invention preferably has a liquid crystal resistivity holding ratio of 10% or more. If it is less than 10%, the alignment of the liquid crystal is disturbed, which may be one of the causes of color unevenness. More preferably, it is 50% or more. The liquid crystal specific resistance can be measured by using a known liquid crystal specific resistance measuring device or the like, and the retention ratio of the liquid crystal specific resistance can be obtained by the following equation.

  The liquid crystal display element of the present invention preferably has a nematic-isotropic liquid transition point (NI point) change of 3 ° C. or less. If it exceeds 3 ° C., the alignment of the liquid crystal is disturbed, which may be one of the causes of color unevenness. The nematic-isotropic liquid transition point (NI point) can be measured by using a known thermal analyzer or the like, and the nematic-isotropic liquid transition point (NI point). The change can be obtained by the following equation.

  According to the present invention, when used as at least one of a sealing agent for a liquid crystal display element, a sealing agent for a liquid crystal display element, and a vertical conduction material for a liquid crystal display element, polymerization is performed even when it is in contact with liquid crystal when uncured. The initiator does not elute in the liquid crystal material, and the residue of the polymerization initiator after curing does not become outgassing by heating at the time of liquid crystal realignment, and is excellent in low voltage drivability, high contrast, brightness, In addition, a curable resin composition having a large resistance and a high voltage holding ratio, a liquid crystal display element sealing agent, a liquid crystal display element sealing agent, a liquid crystal display element vertical conduction material, and these are used. 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.

(Example 1)
(1) Production of radical polymerization initiator 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (Ciba Specialty Chemicals Co., Ltd.) was added to the reaction flask. 50 mol) was added and dissolved by heating in a dry air atmosphere.
Into this, 0.05 mol of dibutyltin dilaurate and 100 mol of 2-methacryloxyethylene isocyanate (manufactured by Showa Denko KK) were slowly added dropwise, and after the addition was completed, an isocyanate group remained by infrared absorption spectrum analysis. It was made to react at 90 degreeC until it disappeared, after that, it refine | purified and the radical polymerization initiator A represented by following formula (7) was obtained.

(2) Preparation of curable resin composition 3 parts by weight of the obtained radical polymerization initiator A, 40 parts by weight of partially acrylated epoxy resin (manufactured by Daicel UCB, UVAC 1561), acrylate-modified epoxy resin (Daicel) 20 parts by weight manufactured by UCB, EB3700), 15 parts by weight of spherical silica (manufactured by Admatechs, SO-C1) as filler, 15 parts by weight of Fujicure FXR-1030 (manufactured by Fuji Kasei Kogyo Co., Ltd.), As a coupling agent, 1 part by weight of γ-glycidoxypropyltrimethoxysilane was sufficiently mixed using a paint roll so as to obtain a uniform liquid, thereby obtaining a curable resin composition.

(3) Production of liquid crystal display element 1 part by weight of spacer fine particles (manufactured by Sekisui Chemical Co., Ltd., Micropearl SP-2055) is dispersed in 100 parts by weight of the obtained curable resin composition, It applied with a dispenser to one of the two rubbed alignment films and the glass substrate with a transparent electrode.
Subsequently, a fine drop of liquid crystal (manufactured by Chisso Corporation, JC-5004LA) is dropped onto the entire surface of the sealant frame of the glass substrate with a transparent electrode, and the other glass substrate with a transparent electrode is immediately bonded to the sealant part. The sample was irradiated with ultraviolet rays at 100 mW / cm ² for 30 seconds using a high pressure mercury lamp.
Then, it heated at 120 degreeC for 1 hour, was thermosetted, and obtained the liquid crystal display element.

(Example 2)
50 mol of 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one was placed in the reaction flask and dissolved by heating in a dry air atmosphere.
Into this, 0.05 mol of dibutyltin dilaurate and 50 mol of 2-methacryloxyethylene isocyanate are slowly added dropwise so that the reaction temperature does not exceed 90 ° C. After the addition is completed, an isocyanate group is analyzed by infrared absorption spectrum analysis. Was allowed to react at 90 ° C. until no more remained, and then purified to obtain an intermediate a represented by the following formula (8).

  50 mol of the obtained intermediate a was put in a reaction flask and dissolved by heating in a dry air atmosphere. In the mixture, 0.05 mol of dibutyltin dilaurate and 50 mol of 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanate (manufactured by Degussa, TMHDI) are used so that the reaction temperature does not exceed 90 ° C. Slowly drop the solution, and then drop 2-hydroxyethyl acrylate slowly so that the reaction temperature does not exceed 90 ° C., and react at 90 ° C. until no isocyanate groups remain by infrared absorption spectrum analysis. Thereafter, purification was performed to obtain radical polymerization initiator B represented by the following formula (9).

  In the general formula (9), A represents 2,2,4- and 2,4,4-trimethylhexamethylene groups.

  A curable resin composition was prepared in the same manner as in Example 1 except that the radical polymerization initiator B was used in place of the radical polymerization initiator A to prepare a liquid crystal display device.

Example 3
100 mol of the intermediate a produced in Example 2 was placed in a reaction flask and dissolved by heating in a dry air atmosphere. Into this, 0.1 mol of dibutyltin dilaurate and 50 mol of 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanate were slowly added dropwise so that the reaction temperature would not exceed 90 ° C. After completion, the reaction was carried out at 90 ° C. until no isocyanate group remained by infrared absorption spectrum analysis, followed by purification to obtain radical polymerization initiator C represented by the following formula (10).

  In the general formula (10), A represents 2,2,4- and 2,4,4-trimethylhexamethylene groups.

  A curable resin composition was prepared in the same manner as in Example 1 except that the radical polymerization initiator C was used in place of the radical polymerization initiator A to prepare a liquid crystal display device.

(Example 4)
50 mol of 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one was placed in the reaction flask and dissolved by heating in a dry air atmosphere. Into this, 0.05 mol of dibutyltin dilaurate and 50 mol of 3-isopropenyl-α, α-dimethylbenzyl isocyanate are slowly added dropwise so that the reaction temperature does not exceed 90 ° C. The reaction was carried out at 90 ° C. until no isocyanate group remained by absorption spectrum analysis, followed by purification to obtain an intermediate b represented by the following formula (11).

  The obtained intermediate b (50 mol) was put in a reaction flask and heated and dissolved in a dry air atmosphere. Into this, 0.05 mol of dibutyltin dilaurate and 50 mol of 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanate were slowly added dropwise so that the reaction temperature would not exceed 90 ° C. After completion, glycidol is slowly added dropwise so that the reaction temperature does not exceed 90 ° C., and reacted at 90 ° C. until no isocyanate group remains by infrared absorption spectrum analysis, followed by purification and the following formula (12). The radical polymerization initiator D to be obtained was obtained.

  A curable resin composition was prepared in the same manner as in Example 1 except that the radical polymerization initiator D was used in place of the radical polymerization initiator A to prepare a liquid crystal display device.

(Comparative Example 1)
A curable resin composition was prepared in the same manner as in Example 1 except that “Darocur 1173” (manufactured by Ciba Specialty Chemicals) was used in place of the radical polymerization initiator A, and a liquid crystal display device was produced. did.

(Comparative Example 2)
A curable resin composition was prepared in the same manner as in Example 1 except that “Irgacure 651” (manufactured by Ciba Specialty Chemicals) was used instead of the radical polymerization initiator A, and a liquid crystal display device was produced. did.

The radical polymerization initiators, curable resin compositions, and liquid display elements obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated by the following methods.
The results are shown in Table 1.

(Measurement of specific liquid crystal retention)
In an ampoule bottle (inner diameter: 10.0 mm), 0.5 g of the curable resin composition was added, and 0.5 g of liquid crystal was added. This bottle was put into an oven at 120 ° C. for 1 hour, and after returning to room temperature (25 ° C.), the liquid crystal portion was subjected to a liquid crystal resistivity measuring device (SM-8210, manufactured by Toa Denpa Kogyo Co., Ltd.), and an electrode for liquid (Ando) Using a LE-21 model manufactured by Denki Co., Ltd., the liquid crystal specific resistance was measured in a standard temperature and humidity state (20 ° C., 65% RH). In addition, the liquid crystal specific resistance retention was calculated | required by the following formula.

(Nematic-isotropic liquid transition point (NI point) change measurement)
In an ampoule bottle (inner diameter: 10.0 mm), 0.5 g of the curable resin composition was added, and 0.5 g of liquid crystal was added. The bottle was put into an oven at 120 ° C. for 1 hour, and after returning to room temperature (25 ° C.), the liquid crystal portion was put into an aluminum pan and measured at a temperature rising rate of 10 ° C./min to measure the peak temperature. In addition, MDSC (made by TA Instruments) was used as a thermal analyzer. The change in nematic-isotropic liquid transition point was determined by the following formula.

(Adhesion evaluation)
1 part by weight of spacer fine particles (manufactured by Sekisui Chemical Co., Ltd., Micropearl SP-2055) is dispersed in 100 parts by weight of the curable resin composition, taken on the center of the slide glass, and another slide glass is overlaid thereon. The sealing agent was spread to make the thickness uniform, and ultraviolet rays were irradiated at 100 mW / cm ² for 30 seconds using a high-pressure mercury lamp. Thereafter, heating was performed at 120 ° C. for 1 hour to obtain an adhesion test piece. The adhesive strength of this test piece was measured using a tension gauge.

(Liquid crystal display panel evaluation (color unevenness evaluation))
About the obtained liquid crystal display element, the liquid crystal alignment disorder in the vicinity of the sealant was evaluated by visual observation according to the following criteria immediately after production and after an operation test for 1000 hours under the condition of 65 ° C. and 95% RH. The number of samples was 6.
◎: No color unevenness ○: Color unevenness is slightly △: Color unevenness is slightly ×: Color unevenness is considerable

(Example 5)
After thoroughly mixing the curable resin composition obtained in the same manner as in Example 1 using three rolls so as to form a uniform liquid, the conductive fine particles are used with respect to 100 parts by weight of the curable resin composition. 2 parts by weight of gold-plated metal plating fine particles (manufactured by Sekisui Chemical Co., Ltd., Micropearl AU-206) were mixed and mixed with a vacuum planetary stirrer to prepare a vertical conduction material for a liquid crystal display element.

  A liquid crystal display device was produced in the same manner as in Example 1 except that the vertical conduction pattern was formed on the electrode for vertical conduction by applying the obtained vertical conduction material on the transparent substrate by a dispenser.

  About the obtained liquid crystal display element, liquid crystal display panel evaluation (color unevenness evaluation) was performed similarly, and when the liquid crystal orientation disorder near vertical conduction material was observed visually, there was no color unevenness at all. Also, the conductivity was good.

According to the present invention, when used as at least one of a sealing agent for a liquid crystal display element, a sealing agent for a liquid crystal display element, and a vertical conduction material for a liquid crystal display element, particularly in the production of a liquid crystal display element by a dropping method, Even when in contact with the liquid crystal, the polymerization initiator does not elute into the liquid crystal material, and the residue of the cured polymerization initiator is not outgassed by heating during liquid crystal realignment, and is driven at low voltage Curable resin composition, liquid crystal display element sealing agent, liquid crystal display element sealing agent, and liquid crystal display element that can provide a liquid crystal display element with excellent resistance, high contrast, brightness, etc., and high resistance and high voltage holding ratio And a liquid crystal display device using these materials.

Claims (10)

  Radical polymerization initiator having radical polymerization initiating group dissociated into two active radical species upon irradiation with light and / or heat, a hydrogen bonding functional group, and two or more reactive functional groups in one molecule A curable resin composition comprising:   Both of the two active radical species generated by dissociation of radical polymerization initiating groups by irradiation with light and / or heat have at least one hydrogen-bonding functional group and at least one reactive functional group. The curable resin composition according to claim 1. The curable resin composition according to claim 1 or 2, wherein the radical polymerization initiating group has a structure represented by the following general formula (1).

In the formula, R ¹ and R ² represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group,

Represents an aromatic ring optionally having an alkyl group having 1 to 6 carbon atoms or a halogen group.   The curable resin composition according to claim 1, 2 or 3, wherein at least one of the reactive functional groups is a (meth) acryl group and / or a cyclic ether group.   The curable resin composition according to claim 1, wherein the hydrogen bonding functional group is a urethane group and / or a hydroxyl group.   The curable resin composition according to claim 1, wherein the radical polymerization initiator has a number average molecular weight of 300 or more.   A sealing agent for a liquid crystal display element, comprising the curable resin composition according to claim 1, 2, 3, 4, 5 or 6.   A sealing agent for liquid crystal display elements, comprising the curable resin composition according to claim 1, 2, 3, 4, 5 or 6.   A vertical conducting material for a liquid crystal display element, comprising the curable resin composition according to claim 1, and conductive fine particles. A sealing agent for a liquid crystal display element according to claim 7, a sealing agent for a liquid crystal display element according to claim 8, and a vertical conduction material for a liquid crystal display element according to claim 9 are used. Liquid crystal display element.