JPWO2011118191A1 - Liquid crystal sealant, liquid crystal display panel manufacturing method using the same, and liquid crystal display panel - Google Patents

Abstract

An object of the present invention is to provide a liquid crystal sealing agent that does not change display characteristics even under high temperature and high humidity conditions and has excellent display reliability. The liquid crystal sealant of the present invention is a (meth) acryl-modified epoxy resin obtained by reacting an epoxy resin containing two or more epoxy groups in the molecule with (meth) acrylic acid, a curing agent, and a photopolymerization initiator. The (meth) acryl-modified epoxy resin contains a hydroxyl group produced by a reaction between an epoxy resin containing two or more epoxy groups in the molecule and the (meth) acrylic acid, and the (meth) acrylic The equivalent of (meth) acrylic group / epoxy group of the modified epoxy resin is more than 9, and the hydrogen bondable functional group value including the hydroxyl group is 3 × 10 −3 to 5 × 10 −3 mol / g.

Description

  The present invention relates to a liquid crystal sealant, a method for producing a liquid crystal display panel using the same, and a liquid crystal display panel.

  In recent years, liquid crystal display panels have been widely used as image display panels for various electronic devices such as mobile phones and personal computers. The liquid crystal display panel has a structure in which a liquid crystal material (hereinafter simply referred to as “liquid crystal”) is sandwiched between two transparent substrates having electrodes provided on the surface, and the periphery thereof is sealed with a liquid crystal sealant. It is.

  Although the liquid crystal sealant is used in a small amount, it directly contacts the liquid crystal, which greatly affects the reliability of the liquid crystal display panel. Therefore, in order to achieve high image quality of the liquid crystal display panel, liquid crystal sealants are currently required to have advanced and diverse characteristics.

  Conventionally, liquid crystal display panels are mainly manufactured by a liquid crystal injection method. In general, the liquid crystal injection method is (1) after applying a liquid crystal sealant on one transparent substrate to form a frame, and (2) drying the liquid crystal sealant by precuring the substrate. The other substrate is bonded, (3) the two substrates are heated and pressed, and the substrates are bonded together to form a frame (cell) of the liquid crystal sealant between the substrates, and (4) empty This is a method of manufacturing a liquid crystal display panel by injecting an appropriate amount of liquid crystal into a cell and then sealing the liquid crystal injection port.

  On the other hand, recently, a liquid crystal dropping method has been studied as a method of manufacturing a liquid crystal display panel that is expected to improve productivity. In the liquid crystal dropping method, (1) a liquid crystal sealant is applied on a transparent substrate to form a frame for filling the liquid crystal, (2) a minute liquid crystal is dropped into the frame, and (3) liquid crystal In this method, two substrates are stacked under high vacuum while the sealant is in an uncured state, and then (4) the liquid crystal sealant is cured to produce a panel. Usually, in the liquid crystal dropping method, a light and thermosetting liquid crystal sealant is used, and in the step (3), after the liquid crystal sealant is pre-cured by irradiating light such as ultraviolet rays, it is post-cured by heating. Has been done.

  As a liquid crystal sealing agent for the liquid crystal dropping method, for example, it has been proposed to use a liquid epoxy resin (Patent Document 1). However, this epoxy resin is soluble in liquid crystals even at room temperature, and becomes a factor that degrades the display characteristics of the liquid crystal display panel.

  On the other hand, a liquid crystal sealant using a crystalline epoxy resin such as an ether type epoxy resin as a resin that is difficult to dissolve in a liquid crystal (for example, Patent Document 2); a liquid crystal containing an acrylic acid-modified phenol novolac epoxy resin and a urethane-modified partial acrylic modified product Sealing agents (for example, Patent Document 3) have been proposed.

Japanese Patent No. 3955038 JP 2005-018022 A JP 2006-124698 A

  The resins described in Patent Documents 2 and 3 have low solubility in liquid crystals at room temperature to some extent. However, since the resin easily dissolves in the liquid crystal under high temperature and high humidity conditions, the display characteristics of the liquid crystal display panel may be deteriorated. In particular, in the liquid crystal dropping method, since the uncured liquid crystal sealant comes into contact with the liquid crystal, the components of the liquid crystal sealant are easily dissolved in the liquid crystal, which is likely to deteriorate the display characteristics of the liquid crystal display panel.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal sealant having excellent display reliability without changing display characteristics even under high temperature and high humidity conditions.

  As described above, in order not to deteriorate the display characteristics of the liquid crystal display panel, it is important to suppress dissolution of the liquid crystal sealant in the liquid crystal. Dissolution of the resin in the liquid crystal can be suppressed to some extent by using a crystalline resin, but the resin is likely to dissolve particularly at high temperatures, and thus may be dissolved in the liquid crystal. Furthermore, since the conventional liquid crystal sealing agent that suppresses dissolution in liquid crystal tends to have a high viscosity, there is a problem that the coating property and workability are low.

  On the other hand, the present inventors react a part of the epoxy group of the epoxy resin with (meth) acrylic acid to introduce a hydroxyl group (which has low compatibility with the liquid crystal) into the resin. Attention was focused on a method for suppressing the dissolution in the water. And it has been found that the solubility of the resin in the liquid crystal is greatly influenced not only by the absolute number of hydroxyl groups contained in the resin but also by the ratio (balance) of the number of hydroxyl groups to the number of unreacted epoxy groups. It was. That is, the ratio of the number of hydroxyl groups to the number of unreacted epoxy groups is increased; specifically, the range of hydrogen-bonding functional groups is set to a certain range, and the equivalent of (meth) acrylic groups / epoxy groups It was found that dissolution in liquid crystal can be suppressed by setting the equivalent weight to a certain value or more. The present invention has been made based on such findings.

The first of the present invention relates to a liquid crystal sealant.
[1] A (meth) acryl-modified epoxy resin obtained by reacting an epoxy resin containing two or more epoxy groups in the molecule with (meth) acrylic acid; a thermosetting agent; and a photopolymerization initiator. The (meth) acryl-modified epoxy resin has a hydrogen-bonding functional group containing a hydroxyl group generated by a reaction between the epoxy resin containing two or more epoxy groups in the molecule and the (meth) acrylic acid, And the equivalent of (meth) acryl group / equivalent of epoxy group of the (meth) acryl-modified epoxy resin is more than 9, and the hydrogen bondable functional group value is 3 × 10 ^{−3 to} 5 × 10 ⁻³ mol / Liquid crystal sealing agent which is g.
[2] The epoxy resin containing two or more epoxy groups in the molecule is a bifunctional epoxy resin selected from the group consisting of a biphenyl type epoxy resin, a naphthalene type epoxy resin, and a bisphenol type epoxy resin. [1] Liquid crystal sealing agent as described in 2.
[3] The liquid crystal sealant according to [2], wherein the bifunctional epoxy resin is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin.
[4] In any one of [1] to [3], further including 1 to 20 parts by weight of a solid epoxy resin having a softening point of 40 ° C. or higher and 150 ° C. or lower with respect to 100 parts by weight of the liquid crystal sealant. Liquid crystal sealing agent of description.
[5] The photopolymerization initiator is at least one compound selected from the group consisting of alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, and oxime ester compounds, [1] to [1] 4] The liquid crystal sealing agent in any one of.
[6] The liquid crystal sealant according to any one of [1] to [5], wherein the thermosetting agent has a melting point of 50 ° C or higher and 250 ° C or lower.
[7] The liquid crystal sealing agent according to any one of [1] to [6], which is at least one selected from the group consisting of organic acid dihydrazide compounds, imidazole compounds, dicyandiamide compounds, and polyamine compounds.
[8] The liquid crystal sealant according to any one of [1] to [7], which is used for manufacturing a liquid crystal display panel by a liquid crystal dropping method.

The second aspect of the present invention relates to a method for manufacturing a liquid crystal display panel using a liquid crystal sealant.
[9] A step of forming a seal pattern on one substrate using the liquid crystal sealant according to any one of [1] to [8], and a seal pattern region of the one substrate when the seal pattern is uncured A step of dropping a liquid crystal on the other substrate which is paired with the one substrate, a step of superimposing the one substrate on the other substrate, and photocuring the seal pattern, followed by thermosetting A method of manufacturing a liquid crystal display panel.
[10] A display substrate, a counter substrate paired with the display substrate, a frame-shaped sealing member interposed between the display substrate and the counter substrate, and between the display substrate and the counter substrate A liquid crystal layer filled in a space surrounded by the seal member, wherein the seal member is a cured liquid crystal sealant according to any one of [1] to [8] A liquid crystal display panel.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal sealing agent excellent in display reliability can be provided.

1. Liquid crystal sealant The liquid crystal sealant of the present invention comprises (A-1) (meth) acryl-modified epoxy resin, (B) thermosetting agent, and (C) photopolymerization initiator, and (A-2) as necessary. ) Solid epoxy resin, (D) acrylic resin, and (E) filler may be further included.

(A) Epoxy resin (A-1) (Meth) acryl-modified epoxy resin The (meth) acryl-modified epoxy resin in the present invention is preferably an epoxy resin and (meth) acrylic acid, for example, in the presence of a basic catalyst. It is a (meth) acryl-modified epoxy resin obtained by reacting.

  The epoxy resin used as a raw material may be a bifunctional or higher functional epoxy resin having two or more epoxy groups in the molecule, such as bisphenol A type, bisphenol F type, 2,2′-diallyl bisphenol A type, bisphenol AD type, And bisphenol type epoxy resins such as hydrogenated bisphenol type; novolak type epoxy resins such as phenol novolak type, cresol novolak type, biphenyl novolak type, and trisphenol novolak type; biphenyl type epoxy resin; naphthalene type epoxy resin and the like. A (meth) acryl-modified epoxy resin obtained by (meth) acryl modification of a trifunctional or tetrafunctional polyfunctional epoxy resin is preferably a bifunctional epoxy resin because it has a high crosslinking density and is likely to have a low adhesive strength. .

  The bifunctional epoxy resin is preferably a biphenyl type epoxy resin, a naphthalene type epoxy resin, or a bisphenol type epoxy resin. Among them, bisphenol type epoxy resins such as bisphenol A type and bisphenol F type are preferable from the viewpoint of production efficiency. This is because the bisphenol type epoxy resin has advantages such as excellent applicability as compared with the biphenyl ether type epoxy resin.

  The epoxy resin used as a raw material may be one type or a combination of two or more types. Moreover, it is preferable that the epoxy resin used as a raw material is highly purified by a molecular distillation method, a washing method, or the like.

  The reaction between the raw epoxy resin and (meth) acrylic acid is carried out so that the (meth) acryl-modified epoxy resin to be obtained has a (meth) acrylic group equivalent / epoxy group equivalent within a predetermined range. Is preferred.

  That is, the reaction between the raw epoxy resin and (meth) acrylic acid is carried out so that the (meth) acryl-modified epoxy resin to be obtained has a (meth) acrylic group equivalent / epoxy group equivalent of more than 9. It is preferable to carry out so that it may become 9.5 or more. In the present invention, the equivalent of (meth) acryl groups in the (meth) acryl-modified epoxy resin is “average number of (meth) acryl groups contained in one molecule of (meth) acryl-modified epoxy resin / (meth) acryl-modified epoxy”. It is expressed as “weight average molecular weight (Mw) of resin”. Similarly, the equivalent of the epoxy group in the (meth) acryl-modified epoxy resin is “average number of epoxy groups contained in one molecule of (meth) acryl-modified epoxy resin / weight average molecular weight of (meth) acryl-modified epoxy resin (Mw ) ". That is, the equivalent of (meth) acrylic group / equivalent of epoxy group is the same as the average number of (meth) acrylic groups / average number of epoxy groups.

  (Meth) acrylic group equivalent / epoxy group equivalent is less than 9 (meth) acryl-modified epoxy resin has a small number of hydroxyl groups (generated by reaction) with respect to the number of unreacted epoxy groups; Alternatively, since the ratio of the reaction product (epoxy resin containing a hydroxyl group) to the unreacted product (epoxy resin containing no hydroxyl group) is small, it is difficult to obtain an effect of suppressing dissolution in the liquid crystal material.

  This will be specifically explained with an example in which the raw epoxy resin is a bifunctional epoxy resin. When the bifunctional epoxy resin and (meth) acrylic acid are reacted, 1) both of the two epoxy groups are not yet present. Unreacted material remaining in the reaction, 2) partial (meth) acrylate obtained by modifying one epoxy group with (meth) acrylic acid, and 3) both of the two epoxy groups modified with (meth) acrylic acid Three types of all (meth) acrylates are produced. When bifunctional epoxy resin and (meth) acrylic acid are reacted so that the number of (meth) acryl groups / the number of epoxy groups is 1, dissolution in liquid crystal is remarkable. 1) Unreacted product It has been confirmed that about 25 mol% remains. On the other hand, when the reaction is carried out so that the number of (meth) acrylic groups / epoxy groups exceeds 9, 1) the dissolution in the liquid crystal is remarkable 1) the proportion of unreacted substances can be reduced to 2 mol% or less. And dissolution in the liquid crystal can be remarkably suppressed.

  In particular, the (meth) acryl-modified epoxy resin used in the present invention preferably has a relatively flexible skeleton and may have low crystallinity. Such a sealing agent containing a (meth) acryl-modified epoxy resin tends to have a relatively low viscosity and is easily dissolved in a liquid crystal. By setting the ratio of the equivalent of (meth) acrylic group / equivalent of epoxy group to more than 9, even such a low-viscosity (meth) acryl-modified epoxy resin can be made difficult to dissolve in the liquid crystal.

  Such a (meth) acryl-modified epoxy resin may have a weight average molecular weight of, for example, about 310 to 500. The weight average molecular weight Mw of the (meth) acryl-modified epoxy resin can be measured, for example, by gel permeation chromatography (GPC).

  On the other hand, if the ratio of the equivalent of (meth) acrylic group / equivalent of epoxy group exceeds 9 and becomes too large, the hydroxyl group produced by the addition reaction of (meth) acrylic acid increases, so the moisture resistance of the cured product decreases. Sometimes. For this reason, it is preferable to set the upper limit of the ratio of equivalents of (meth) acrylic groups / equivalents of epoxy groups so that the moisture resistance is not significantly impaired. Alternatively, as described later, (A-2) a solid epoxy resin having a softening point of 40 to 150 ° C. is used in combination; (B) a thermosetting agent as a thermosetting agent is used together with a high melting point, moisture resistance Can also be maintained.

  In addition, the (meth) acryl-modified epoxy resin having a (meth) acryl group equivalent / epoxy group equivalent ratio of less than 9 has a low photo-curability because the content ratio of the (meth) acryl group is small. Therefore, the temporary curing of the liquid crystal sealant with light tends to be insufficient, and it may be difficult to suppress elution into the liquid crystal.

  The (meth) acryl-modified epoxy resin has a hydrogen bonding functional group such as a hydroxyl group, a urethane bond, an amide group, or a carboxyl group. Examples of such hydrogen-bonding functional groups include at least a hydroxyl group produced by the reaction of the epoxy group of the epoxy resin with (meth) acrylic acid, which is a raw material for the (meth) acryl-modified epoxy resin ( A hydroxyl group, a urethane bond, a carboxyl group, an amide group and the like contained in (meth) acrylic acid and epoxy resin are also included. Since a resin having a hydrogen bonding functional group has low compatibility with a liquid crystal material that is hydrophobic, dissolution in the liquid crystal material is suppressed.

The hydrogen bonding functional group value of the (meth) acryl-modified epoxy resin is preferably 3 × 10 ^{−3 to} 5 × 10 ⁻³ mol / g, and 3.5 × 10 ^{−3 to} 4.5 × 10 ^−. More preferably, it is ³ mol / g. When the hydrogen bondable functional group value is less than 3 × 10 ⁻³ mol / g, the number of hydrogen bondable functional groups contained in one molecule of (meth) acryl-modified epoxy resin is small, so that the dissolution in the liquid crystal is suppressed. This is because it is difficult to obtain the effect, and when it exceeds 5 × 10 ⁻³ mol / g, the moisture resistance of the cured product of the (meth) acryl-modified epoxy resin tends to decrease.

  The hydrogen bonding functional group value (mol / g) of the (meth) acryl-modified epoxy resin is “the number of hydrogen bonding functional groups contained in one molecule of the (meth) acryl-modified epoxy resin” / “(meth) acryl modification”. It is expressed as “weight average molecular weight (Mw) of epoxy resin”. For example, as a hydrogen bonding functional group, the hydrogen bonding functional group value of a (meth) acryl-modified epoxy resin having only a hydroxyl group obtained by reacting (meth) acrylic acid with an epoxy resin is reacted (meth). It can be determined by dividing the number of moles of acrylic acid by the weight average molecular weight (Mw) of the (meth) acryl-modified epoxy resin.

  The hydrogen bonding functional group value of the (meth) acryl-modified epoxy resin can be adjusted, for example, by adjusting the number of moles of (meth) acrylic acid to be reacted with the raw material epoxy resin; the raw material (meth) acrylic acid or epoxy resin It can be controlled by adjusting the amount of the hydrogen-bonding functional group possessed by.

The hydroxyl value of the (meth) acryl-modified epoxy resin obtained by reacting the epoxy resin as a raw material with (meth) acrylic acid is preferably 3 × 10 ^{−3 to} 5 × 10 ⁻³ mol / g. .

  The content of the (meth) acryl-modified epoxy resin is preferably 10 to 70 parts by mass and more preferably 20 to 50 parts by mass with respect to 100 parts by mass of the liquid crystal sealant.

  Thus, since the (meth) acryl-modified epoxy resin has an epoxy group and a (meth) acryl group in the molecule, it can have both photocurability and thermosetting properties. Furthermore, even if the (meth) acryl-modified epoxy resin is an amorphous epoxy resin, since the ratio of the number of hydroxyl groups to the number of epoxy groups is large, dissolution in liquid crystals can be highly suppressed.

(A-2) Solid epoxy resin The liquid-crystal sealing compound of this invention may also contain the solid epoxy resin whose softening point is 40 to 150 degreeC as needed. Such a solid epoxy resin has low solubility and diffusibility in liquid crystal, and not only good display characteristics of the resulting liquid crystal panel, but also can improve the moisture resistance of the cured product.

  Such a solid epoxy resin may be an aromatic epoxy resin having a weight average molecular weight of 500 to 10,000, preferably 1000 to 5,000. The weight average molecular weight of the solid epoxy resin can be measured in the same manner as described above.

  Examples of such aromatic epoxy resins include aromatic diols represented by bisphenol A, bisphenol S, bisphenol F, bisphenol AD, and the like, and diols obtained by modifying them with ethylene glycol, propylene glycol, alkylene glycol, and epichlorohydrin. Aromatic polyvalent glycidyl ether compounds obtained by the reaction with phenol; novolak resins derived from phenol or cresol and formaldehyde, polyphenols typified by polyalkenylphenol and copolymers thereof, and obtained by the reaction of epichlorohydrin In addition, novolak-type polyvalent glycidyl ether compounds; glycidyl ether compounds of xylylene phenol resin, and the like are included.

  The above aromatic epoxy resins include, among others, cresol novolac type epoxy resins, phenol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, triphenolmethane type epoxy resins, triphenolethane type epoxy resins, trisphenol type epoxy resins. Resin, dicyclopentadiene type epoxy resin, diphenyl ether type epoxy resin, and biphenyl type epoxy resin are preferable. Furthermore, you may mix and use these.

  The content of the solid epoxy resin is preferably 1 to 20 parts by mass and more preferably 3 to 10 parts by mass with respect to 100 parts by mass of the liquid crystal sealant. If the content of the solid epoxy resin is too large, the viscosity of the liquid crystal sealing agent may increase and the coating property may decrease. If the content of the solid epoxy resin is too small, the moisture resistance of the cured product of the liquid crystal sealing agent may decrease. It may be insufficient.

  The mass ratio of (A-1) (meth) acrylic modified epoxy resin to (A-2) solid epoxy resin ((meth) acrylic modified epoxy resin / solid epoxy resin) is the viscosity stability of the liquid crystal sealant and the cured product. It may be adjusted from the viewpoint of achieving both the moisture resistance. If the mass ratio is too large, the content of the solid epoxy resin is small, so the moisture resistance of the cured liquid crystal sealant may be insufficient. If the mass ratio is too small, the content of the solid epoxy resin Since there are many, a viscosity becomes high and applicability | paintability may fall.

(B) Thermosetting agent Even if it is mixed with an epoxy resin, the thermosetting agent does not cure the epoxy resin under normal storage conditions (room temperature, under visible light, etc.). A curing agent to be cured. The liquid crystal sealing agent containing a thermosetting agent is excellent in storage stability and thermosetting. The thermosetting agent used in the present invention may be a known one, but from the viewpoint of enhancing the viscosity stability of the liquid crystal sealant and maintaining moisture resistance, the melting point is 50 ° C., although depending on the thermosetting temperature. A thermosetting agent having a melting point of 250 ° C. or lower is preferable, a thermosetting agent having a melting point of 100 ° C. or higher and 200 ° C. or lower is more preferable, and a thermosetting agent having a melting point of 150 ° C. or higher and 200 ° C. or lower is further preferable.

  Preferable examples of such thermosetting agents include organic acid dihydrazide compounds, imidazole compounds, dicyandiamide compounds, polyamine compounds, and the like.

  Examples of organic acid dihydrazide compounds include adipic acid dihydrazide (melting point 181 ° C.), 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (melting point 120 ° C.), 7,11-octadecadien-1 , 18-dicarbohydrazide (melting point 160 ° C.), dodecanedioic acid dihydrazide (melting point 190 ° C.), sebacic acid dihydrazide (melting point 189 ° C.), and the like. Examples of imidazole compounds include 2,4-diamino-6- [2′-ethylimidazolyl- (1 ′)]-ethyltriazine (melting point 215 to 225 ° C.) and 2-phenylimidazole (melting point 137 to 147 ° C. ) Etc. are included. Examples of the dicyandiamide compound include dicyandiamide (melting point: 209 ° C.). The polyamine compound is a thermal latent curing agent having a polymer structure obtained by reacting an amine and an epoxy. Specific examples thereof include ADEKA Hardener EH4339S (softening point 120 to 130 ° C.) manufactured by ADEKA, and ADEKA Co., Ltd. Adeka Hardener EH4357S (softening point 73-83 ° C.) and the like are included. These may be used alone or in combination.

  The addition amount of the thermosetting agent is preferably adjusted so that the active hydrogen equivalent is 0.8 to 1.2 equivalents relative to the epoxy equivalent. A liquid crystal sealant containing a thermosetting agent can be a so-called one-part curable resin composition. The one-component curable resin composition is excellent in workability because it is not necessary to mix the main agent and the curing agent when used.

(C) Photopolymerization initiator The photopolymerization initiator is an initiator for photocuring reaction of (A-1) (meth) acryl-modified epoxy resin or (D) acrylic resin described later. When the liquid crystal sealant contains a photopolymerization initiator, the sealant can be temporarily cured by photocuring when manufacturing a liquid crystal panel, and the work process becomes easy.

  Known photopolymerization initiators can be used. Examples include alkylphenone compounds, acyl phosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, thioxanthone compounds, α-acyloxime ester compounds, Phenyl glyoxylate compounds, benzyl compounds, azo compounds, diphenyl sulfide compounds, organic dye compounds, iron-phthalocyanine compounds, benzoin ether compounds, anthraquinone compounds, and the like are included.

  Examples of alkylphenone compounds include benzyl dimethyl ketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one (IRGACURE 651); 2-methyl-2-morpholino (4-thiomethylphenyl) propane Α-aminoalkylphenones such as -1-one (IIRGACURE 907); α-hydroxyalkylphenones such as 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE 184) and the like. Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. The titanocene-based compound includes bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium and the like. Examples of the oxime ester compounds include 1.2-octanedione-1- [4- (phenylthio) -2- (0-benzoyloxime)] (IRGACURE OXE 01) and the like.

  The content of the photopolymerization initiator is the sum of (A-1) (meth) acryl-modified epoxy resin, (A-2) solid epoxy resin, (B) thermosetting agent, and (D) acrylic resin described below (below). It is also 0.3 to 5.0 parts by mass with respect to 100 parts by mass) (also referred to as “resin unit”). When the content is 0.3 parts by mass or more, the curability of the liquid crystal sealant by light irradiation becomes good, and when the content is 5.0 parts by mass or less, the stability at the time of application to the substrate becomes good. .

(D) Acrylic resin The liquid-crystal sealing compound of this invention may contain the acrylic resin as needed. Examples of acrylic resins include diacrylates and / or dimethacrylates such as polyethylene glycol, propylene glycol and polypropylene glycol; triacrylate (2-hydroxyethyl) isocyanurate diacrylate and / or dimethacrylate; 4 per mole of neopentyl glycol. Diacrylate and / or dimethacrylate of diol obtained by adding at least 1 mole of ethylene oxide or propylene oxide; Diacrylate and / or diacrylate of diol obtained by adding 2 mole of ethylene oxide or propylene oxide to 1 mole of bisphenol A Methacrylate: Diol or triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane. Acrylates and / or di- or trimethacrylates; Diacrylates and / or dimethacrylates of diols obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A; Tris (2-hydroxyethyl) isocyanurate triacrylate and Trimethylolpropane triacrylate and / or trimethacrylate, or oligomer thereof; pentaerythritol triacrylate and / or trimethacrylate, or oligomer thereof; polyacrylate and / or polymethacrylate of dipentaerythritol; tris (acryloxy) Ethyl) isocyanurate; caprolactone-modified tris (acryloxyethyl) isocyanur Caprolactone-modified tris (methacryloxyethyl) isocyanurate; alkyl-modified dipentaerythritol polyacrylate and / or polymethacrylate; caprolactone-modified dipentaerythritol polyacrylate and / or polymethacrylate; hydroxypivalate neopentyl glycol diacrylate And / or dimethacrylate; caprolactone modified hydroxypivalate neopentyl glycol diacrylate and / or dimethacrylate; ethylene oxide modified phosphate acrylate and / or dimethacrylate; ethylene oxide modified alkylated phosphate acrylate and / or dimethacrylate; neopentyl Glucol, trimethylolpropane, pentaerythritol These oligoacrylates and / or oligomethacrylates are included.

  The content of the acrylic resin is preferably 5 to 40 parts by mass and more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the liquid crystal sealant, although it depends on the required photocuring degree. preferable.

(E) Filler The liquid crystal sealing agent of the present invention may further contain a filler. By adding the filler, it is possible to control the viscosity of the liquid crystal sealant, the strength of the cured product, the linear expansion, and the like.

  The filler is not particularly limited, but examples include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, aluminum oxide (alumina), zinc oxide, silicon dioxide, titanium. Inorganic fillers such as potassium acid, kaolin, talc, glass beads, sericite activated clay, bentonite, aluminum nitride and silicon nitride are included, preferably silicon dioxide and talc.

The shape of the filler is not particularly limited, and may be a regular shape such as a spherical shape, a plate shape, or a needle shape, or an irregular shape. Filler preferably has an average primary particle diameter of 1.5μm or less, and it is preferable that the specific surface area of 0.5m ² / g~20m ² / g. The average primary particle diameter of the filler can be measured by a laser diffraction method described in JIS Z8825-1. The specific surface area can be measured by the BET method described in JIS Z8830.

  The filler filling amount is the sum of (A-1) (meth) acryl-modified epoxy resin, (A-2) solid epoxy resin, (B) thermosetting agent, and (D) acrylic resin (hereinafter referred to as “resin unit”). It is preferable that it is 1-50 mass parts with respect to 100 mass parts, and it is more preferable that it is 10-30 mass parts.

(F) Thermoplastic resin particles The liquid crystal sealant of the present invention may contain thermoplastic resin particles (also referred to as “epoxy-modified particles”) modified with an epoxy resin as necessary. The thermoplastic resin particles are obtained by suspension polymerization of a resin containing an epoxy group and a double bond group with a monomer capable of radical polymerization. The thermoplastic resin particles are preferably added when making a liquid crystal sealing agent for a liquid crystal injection method. This is because the shrinkage stress generated in the cured product by heating can be relaxed.

  Examples of the resin containing an epoxy group and a double bond group include a resin obtained by reacting a bisphenol F type epoxy resin and methacrylic acid in the presence of a tertiary amine. Examples of radically polymerizable monomers include butyl acrylate, glycidyl methacrylate, and divinylbenzene. The average particle diameter of the thermoplastic resin particles is usually in the range of 0.05 to 5 μm, preferably 0.07 to 3 μm, since the gap of the liquid crystal cell is mainly 5 μm or less.

  The thermoplastic resin particles are preferably 1 to 30 parts by mass with respect to 100 parts by mass of the resin unit.

(G) Other additives The liquid crystal sealing agent of the present invention includes a thermal radical polymerization initiator, a coupling agent such as a silane coupling agent, an ion trapping agent, an ion exchange agent, a leveling agent, a pigment, a dye, if necessary. An additive such as a plasticizer and an antifoaming agent may be further included. Further, a spacer or the like may be blended in order to adjust the gap of the liquid crystal panel.

  Since the liquid crystal sealing agent of the present invention contains (A-1) (meth) acryl-modified epoxy resin, (B) thermosetting agent, and (C) photopolymerization initiator, photocuring and thermosetting are used in combination. It is preferably used for a liquid crystal sealant for a liquid crystal dropping method. The liquid crystal sealing agent for the liquid crystal dropping method preferably further includes (A-2) a solid epoxy resin and (D) an acrylic resin, and more preferably further includes (E) a filler.

  The viscosity at 25 ° C. and 2.5 rpm using the E-type viscometer of the liquid crystal sealant of the present invention is preferably 30 to 350 Pa · s. This is because the liquid crystal sealant having a viscosity in the above range is excellent in coating properties.

2. Manufacturing method of liquid crystal display panel The liquid crystal display panel of the present invention is a display substrate, a counter substrate that is paired with the display substrate, a frame-shaped sealing member interposed between the display substrate and the counter substrate, and a display substrate. And a liquid crystal layer filled in a space surrounded by a sealing member between the substrate and the substrate. The cured product of the liquid crystal sealant of the present invention can be used as a seal member.

  Both the display substrate and the counter substrate are transparent substrates. The material of the transparent substrate can be glass or plastic such as polycarbonate, polyethylene terephthalate, polyethersulfone and PMMA.

  Matrix TFTs, color filters, black matrices, and the like can be disposed on the surface of the display substrate or the counter substrate. An alignment film is further formed on the surface of the display substrate or the counter substrate. The alignment film includes a known organic alignment agent or inorganic alignment agent.

  Such a liquid crystal display panel can be manufactured using the liquid crystal sealant of the present invention. The liquid crystal display panel manufacturing method includes a liquid crystal dropping method and a liquid crystal injection method.

The manufacturing method of the liquid crystal display panel by the liquid crystal dropping method is
a1) a first step of forming a seal pattern of the liquid crystal sealant of the present invention on one substrate;
a2) a second step of dropping liquid crystal in a region surrounded by the seal pattern of the substrate or a region of the other substrate facing the region surrounded by the seal pattern in an uncured state of the seal pattern;
a3) a third step of superimposing one substrate and the other substrate via a seal pattern;
a4) a fourth step of curing the seal pattern.

  The state in which the seal pattern is uncured in the step a2) means a state in which the curing reaction of the liquid crystal sealant has not progressed to the gel point. Therefore, in the step a2), the seal pattern may be semi-cured by light irradiation or heating in order to suppress dissolution of the liquid crystal sealant in the liquid crystal. One substrate and the other substrate are a display substrate or a counter substrate, respectively.

  In the step a4), only curing by heating may be performed, but it is preferable to perform curing (main curing) by heating after curing by light irradiation (temporary curing). This is because the liquid crystal sealant can be instantly cured by temporary curing by light irradiation to suppress dissolution in the liquid crystal.

  The photocuring time is, for example, about 10 minutes although it depends on the composition of the liquid crystal sealant. The light irradiation energy may be energy that can cure (A-1) (meth) acryl-modified epoxy resin, (D) acrylic resin, or the like. The light is preferably ultraviolet light. The thermosetting temperature is 120 ° C., for example, although it depends on the composition of the liquid crystal sealant, and the thermosetting time is about 2 hours.

  In the liquid crystal dropping method, since the contact time between the uncured liquid crystal sealant and the liquid crystal is relatively long, liquid crystal contamination is likely to occur. On the other hand, since the liquid crystal sealant of the present invention has low solubility in liquid crystals, the liquid crystal display panel obtained by the liquid crystal dropping method using the liquid crystal sealant of the present invention is excellent in display reliability.

The manufacturing method of the liquid crystal display panel by the liquid crystal injection method is
b1) a first step of forming a seal pattern of the liquid crystal sealant of the present invention on one substrate;
b2) a second step of superimposing one substrate and the other substrate via a seal pattern;
b3) a third step of thermosetting the seal pattern to obtain a liquid crystal injection cell having an injection port for injecting liquid crystal;
b4) a fourth step of injecting the liquid crystal into the liquid crystal injection cell through the injection port;
b5) a fifth step of sealing the inlet.

  In the steps b1) to b3), a liquid crystal injection cell is prepared. First, two transparent substrates (for example, glass plates) are prepared. Then, a seal pattern is formed on one substrate with a liquid crystal sealant. After the other substrate is superimposed on the surface of the substrate where the seal pattern is formed, the seal pattern may be cured. At this time, it is necessary to provide an injection port for injecting liquid crystal in a part of the liquid crystal injection cell, but the injection port may be provided with a part of the opening when drawing the seal pattern. Moreover, after forming the seal pattern, the seal pattern at a desired location may be removed to provide an injection port.

  Although the thermosetting conditions in the process of b3) are based also on a composition of a liquid-crystal sealing compound, it is about 2 to 5 hours at 150 degreeC, for example.

  Step b4) may be performed according to a known method in which the inside of the liquid crystal injection cell obtained in steps b1) to b3) is evacuated and liquid crystal is sucked from the injection port of the liquid crystal injection cell. Good. In the step b5), the liquid crystal sealant may be cured after being sealed in the injection port of the liquid crystal injection cell.

  In the liquid crystal injection method, the time for which the uncured liquid crystal sealant and the liquid crystal are in contact is relatively short. However, the liquid crystal may be injected even if the liquid crystal sealing agent of the liquid crystal injection cell is not sufficiently cured. Since the liquid crystal sealant of the present invention has low solubility in liquid crystal, it is difficult to contaminate the liquid crystal even in such a case. Therefore, a liquid crystal display panel excellent in display reliability can be obtained also by a liquid crystal injection method using the liquid crystal sealant of the present invention.

[Synthesis Example 1]
Synthesis of methacrylic acid-modified bisphenol F type epoxy resin (95% partially methacrylic product)
160 g of liquid bisphenol F type epoxy resin (Epototo YDF-8170C manufactured by Tohto Kasei Co., Ltd., epoxy equivalent 160 g / eq), 0.1 g of p-methoxyphenol as a polymerization inhibitor, 0.2 g of triethanolamine as a catalyst, and 81. 7 g of methacrylic acid was charged into the flask, dried air was fed into the flask, and the mixture was reacted at 90 ° C. with reflux stirring for 5 hours. The obtained compound was washed 20 times with ultrapure water to obtain a methacrylic acid-modified bisphenol F type epoxy resin.

  Here, the number of epoxy groups contained in the raw material bisphenol F type epoxy resin is 1 mol. The number of methacryl groups contained in the methacrylic acid to be reacted is 0.95 mol. Therefore, the obtained methacrylic acid-modified bisphenol F type epoxy resin is a 95% partially methacrylic product, and the ratio of the methacryl group equivalent / epoxy group equivalent is 0.95 / 0.05 (= 19).

The average molecular weight of the methacrylic acid-modified bisphenol F-type epoxy resin is 0.95 × 2 (= 1.9) of hydroxyl groups (number of hydrogen-bonding functional groups) contained in one molecule of the methacrylic acid-modified bisphenol F-type epoxy resin. The hydrogen bondable functional group value was calculated by dividing by 483.4 (= 492 × 0.95 + 320 × 0.05) and found to be 3.93 × 10 ⁻³ (mol / g). The molecular weight of bisphenol F type epoxy is 320, and the molecular weight of methacrylic acid-modified bisphenol F type epoxy resin at both ends is 492.

[Synthesis Example 2]
Synthesis of methacrylic acid-modified bisphenol F type epoxy resin (50% partially acrylated product)
A methacrylic acid-modified bisphenol F-type epoxy resin (50% partially methacrylic product) was obtained in the same manner as in Synthesis Example 1 except that the amount of methacrylic acid charged was 43 g.

  Here, the number of epoxy groups contained in the raw material bisphenol F-type epoxy resin is 1 mol, as described above. The number of methacryl groups contained in the methacrylic acid to be reacted is 0.5 mol. Therefore, the methacrylic acid-modified bisphenol F-type epoxy resin obtained is a 50% partially methacrylic product, and the ratio of the methacryl group equivalent / epoxy group equivalent is 0.5 / 0.5 (= 1). .

Further, the hydrogen bondable functional group value of the methacrylic acid-modified bisphenol F type epoxy resin is determined by the number of hydroxyl groups (hydrogen bondable functional group number) 0.5 × 2 in one molecule of the methacrylic acid modified bisphenol F type epoxy resin. = 1.0) was calculated by dividing the average molecular weight of the methacrylic acid-modified bisphenol F type epoxy resin (406 = 492 × 0.5 + 320 × 0.5) by 2.46 × 10 ⁻³ (mol). / G).

[Synthesis Example 3]
Synthesis of acrylic acid-modified phenol novolac epoxy resin (50% partially acrylate)
179 g liquid phenol novolac type epoxy resin (Dow Chemical Co .: DEN431 epoxy equivalent 179 g / eq), 0.2 g p-methoxyphenol as polymerization inhibitor, 0.2 g triethylamine as catalyst, and 36 g acrylic acid in flask The mixture was charged into the inside, and dried air was fed in, and the mixture was reacted at 90 ° C. with stirring under reflux for 5 hours. The obtained compound was washed 20 times with ultrapure water to obtain an acrylic acid-modified phenol novolac type epoxy resin (50% partially acrylated product).

  Here, the number of epoxy groups contained in the novolac type epoxy resin as a raw material is 1.0 mol. The number of acrylic groups contained in the acrylic acid to be reacted is 0.5 mol. Therefore, the obtained acrylic-modified phenol novolac epoxy resin is a 50% partially methacrylic product, and the ratio of equivalent of acrylic group / equivalent of epoxy group is 0.5 / 0.5 = 1.0.

In addition, the hydrogen bondable functional group value of the acrylic modified phenol novolac epoxy resin is 0.5 × 2 (= 1) hydroxyl groups (hydrogen bond functional group number) contained in one molecule of the acrylic modified phenol novolac epoxy resin. It was 2.3 × 10 ⁻³ (mol / g) when calculated by dividing by the average molecular weight (430 = 179 × 2 + 72) of the acrylic acid-modified phenol novolac type epoxy resin.

[Synthesis Example 4]
13.4 g of trimethylolpropane, 0.02 g of BHT as a polymerization inhibitor, 0.001 g of dibutyltin dilaurate and 66.6 g of isophorone diisocyanate as a catalyst were added and reacted at 60 ° C. with reflux stirring for 2 hours. Next, 2.55 g of 2-hydroxyethyl acrylate and 11.1 g of glycidol were added, and the mixture was reacted for 2 hours while stirring at 90 ° C. while feeding dry air. The obtained compound was washed 20 times with ultrapure water to obtain a urethane-modified partially acrylated product.

  Here, the number of epoxy groups contained in the raw material glycidol is 0.15 mol. The number of acrylic groups contained in 2-hydroxyethyl acrylate is 0.022 mol. Therefore, the ratio of the equivalent of acrylic group / equivalent of epoxy group is 0.022 / 0.128 (= 0.172) in the resulting urethane-modified partially acrylated product.

Further, the hydrogen bondable functional group value of the urethane-modified partially acrylated product is divided by the average molecular weight of the urethane-modified partially acrylated product by the number of urethane bonds (hydrogen bondable functional groups) contained in one molecule of the urethane-modified partially acrylated product. It was 3.0 * 10 < ^-3 > (mol / g) when computed by this.

[Synthesis Example 5]
Synthesis of methacrylic acid-modified bisphenol A type epoxy resin (90% partially methacrylic product)
185 g of liquid bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin, trade name Epicron YL980, epoxy equivalent 185 g / eq), 0.1 g of p-methoxyphenol as a polymerization inhibitor, 0.2 g of triethanolamine as a catalyst, And 77.4 g of methacrylic acid were charged into the flask, dried air was fed into the flask, and the mixture was reacted at 90 ° C. with reflux stirring for 5 hours. The obtained compound was washed 20 times with ultrapure water to obtain a methacrylic acid-modified bisphenol A type epoxy resin.

  Here, the number of epoxy groups contained in the raw material bisphenol A type epoxy resin is 1 mol. The number of methacryl groups contained in the methacrylic acid to be reacted is 0.90 mol. Therefore, the obtained methacryl-modified bisphenol A type epoxy resin is a 90% partially methacrylic product, and the ratio of the methacryl group equivalent / epoxy group equivalent is 0.90 / 0.10 (= 9).

Further, the hydrogen bondable functional group value of the methacryl-modified bisphenol A type epoxy resin is the number of hydroxyl groups (hydrogen bondable functional group number) contained in one molecule of the methacryl modified bisphenol A type epoxy resin 0.9 × 2 (= 1 .8) calculated by dividing the number by the average molecular weight (500) of the methacryl-modified bisphenol A type epoxy resin, it was 3.6 × 10 ⁻³ (mol / g).

[Synthesis Example 6]
Synthesis of methacrylic acid modified bisphenol A type epoxy resin (85% partially acrylated product)
185 g of liquid bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin, trade name Epicron YL980, epoxy equivalent 185 g / eq), 0.1 g of p-methoxyphenol as a polymerization inhibitor, 0.2 g of triethanolamine as a catalyst, And 73.1 g of methacrylic acid were charged into the flask, dried air was fed, and the mixture was reacted at 90 ° C. with reflux stirring for 5 hours. The obtained compound was washed 20 times with ultrapure water to obtain a methacrylic acid-modified bisphenol A type epoxy resin.

  Here, the number of epoxy groups contained in the raw material bisphenol A type epoxy resin is 1 mol. The number of methacryl groups contained in the methacrylic acid to be reacted is 0.85 mol. Therefore, the obtained methacryl-modified bisphenol A type epoxy resin is a 85% partially methacrylic product, and the ratio of the methacryl group equivalent / epoxy group equivalent is 0.85 / 0.15 (= 5.7). .

In addition, the hydrogen bondable functional group value of the methacryl-modified bisphenol A type epoxy resin is the number of hydroxyl groups (the number of hydrogen bondable functional groups) contained in one molecule of the methacryl modified bisphenol A type epoxy resin 0.85 × 2 (= 1 7) was calculated by dividing the number by the average molecular weight (500) of the methacryl-modified bisphenol A type epoxy resin, and was 3.4 × 10 ⁻³ (mol / g).

Table 1 shows the physical properties of the (meth) acryl-modified epoxy resins obtained in Synthesis Examples 1 to 6.

[Example 1]
43 parts by weight of methacrylic acid-modified bisphenol F type epoxy resin (95% partially methacrylic product) obtained in Synthesis Example 1, 4 parts by weight of solid epoxy resin (manufactured by JER: Epicoat 1004, softening point 97 ° C.), 20 parts by weight of acrylic resin (polyethylene glycol diacrylate, light acrylate 14EG-A manufactured by Kyoeisha Chemical Co., Ltd.), 9 parts by weight of adipic acid dihydrazide (manufactured by Nippon Kasei Co., Ltd., ADH, melting point: 177-184 ° C.), photopolymerization started 2 parts by weight of an alkylphenone polymerization initiator (manufactured by Ciba Specialty Chemicals: IRGACURE651), 13 parts by weight of silica particles: S-100 (manufactured by Nippon Shokubai Chemical), (meth) acrylic acid ester monomer and 7 parts by weight of thermoplastic resin particles obtained by copolymerizing these and a copolymerizable monomer ( A curable resin composition comprising a particle polymer F351 (manufactured by Zeon Kasei Co., Ltd.) and 2 parts by weight of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-403) This was mixed well to obtain a sealant.

[Example 2]
As a thermosetting agent, instead of adipic acid dihydrazide (Nippon Kasei Co., Ltd., ADH), 9 parts by weight of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (Ajinomoto Amicure VDH, melting point 120 ° C. ) Was used in the same manner as in Example 1 except that a sealing agent was obtained.

[Example 3]
A sealing agent was obtained in the same manner as in Example 1 except that no solid epoxy resin was used.

[Comparative Example 1]
Instead of the methacrylic acid modified bisphenol F type epoxy resin (95% partially methacrylic product) obtained in Synthesis Example 1, the methacrylic acid modified bisphenol F type epoxy resin (50% partial methacrylic product) obtained in Synthesis Example 2 was used. A sealant was obtained in the same manner as in Example 1 except that the chemical compound was used.

[Comparative Example 2]
As a thermosetting agent, 9 parts by weight of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (Ajinomoto Amicure VDH) was used instead of adipic acid dihydrazide (Nippon Kasei Co., Ltd., ADH). A sealing agent was obtained in the same manner as in Comparative Example 1 except for the above.

[Comparative Example 3]
43 parts by weight of the acrylic acid-modified phenol novolac epoxy resin (50% partially acrylate) obtained in Synthesis Example 3, 20 parts by weight of urethane-modified partially acrylated product obtained in Synthesis Example 4, and 4 parts by weight of solid epoxy Resin (manufactured by JER: Epicoat 1004, softening point 97 ° C.), 9 parts by weight of 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (Ajinomoto Amicure VDH) as a thermosetting agent, photopolymerization started 2 parts by weight of 2,2′-diethoxyacetophenone, 13 parts by weight of silica particles: S-150 (manufactured by Nippon Shokubai Chemical Co., Ltd.), 7 parts by weight of thermoplastic resin particles (fine particle polymer F351 (manufactured by Zeon Kasei Co., Ltd.) )) And 1 part by weight of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-403), a three-roll roll makes a uniform liquid. The mixture was thoroughly mixed to obtain a sealant.

[Comparative Example 4]
Instead of the methacrylic acid modified bisphenol F type epoxy resin (95% partially methacrylic product) obtained in Synthesis Example 1, the methacrylic acid modified bisphenol A type epoxy resin (90% partial methacrylic product) obtained in Synthesis Example 5 was used. A sealant was obtained in the same manner as in Example 1 except that the chemical compound was used.

[Comparative Example 5]
Instead of the methacrylic acid-modified bisphenol F type epoxy resin (95% partially methacrylic product) obtained in Synthesis Example 1, the methacrylic acid modified bisphenol A type epoxy resin (85% partial methacrylic product) obtained in Synthesis Example 6 A sealant was obtained in the same manner as in Example 1 except that the chemical compound was used.

  Regarding the sealing agents obtained in Examples 1 to 3 and Comparative Examples 1 to 5, 1) viscosity stability, 2) N-I point of liquid crystal, 3) ultraviolet curable, 4) display characteristics of liquid crystal display panel, and 5) Adhesiveness was evaluated by the following method.

1) Viscosity stability The sealing agents obtained in Examples and Comparative Examples were collected so that the weight of the sealing agent in the dispensing syringe was 10 g, and then subjected to defoaming treatment. About 2 g of them, initial viscosity was measured at room temperature (23 degreeC) using the E-type viscosity meter. Next, after the sample was stored at 23 ° C. and 50% RH for 1 week, the viscosity was measured again under the same conditions. At this time, the rate of increase in viscosity after storage for 1 week with respect to the initial viscosity was determined.
◯ (excellent) when the rate of increase in viscosity after storage with respect to the initial viscosity is 1.2 times or less; △ (slightly inferior) when 1.2 times or more and 1.5 times or less; 1.5 times The excess was marked as x (inferior).

2) NI point of liquid crystal (nematic-isotropic phase transition temperature)
0.1 g (uncured) sealing agent obtained in Examples and Comparative Examples and 1 g of liquid crystal (MLC-11900-000, manufactured by Merck & Co., Inc.) were put into a vial and heated at 120 ° C. for 1 hour. As a result, a liquid crystal mixture was obtained. Subsequently, this liquid crystal mixture was taken out, and its N-I point was measured by DTA (differential thermal analysis) at a heating rate of 5 ° C./min.

  The NI point of the liquid crystal changes greatly if the liquid crystal contains impurities even in a small amount. For this reason, the smaller the amount of change of the NI point of the liquid crystal mixture after heating with respect to the NI point of the liquid crystal (before heating), the smaller the dissolution of the sealant component in the liquid crystal. The change amount of the NI point of the liquid crystal mixture with respect to the NI point of the liquid crystal (original) was less than 5 ° C .: ○ (excellent);

3) Ultraviolet Curing The viscosity increasing behavior after irradiation of 5 mW / cm ² ultraviolet rays on the sealants obtained in Examples and Comparative Examples was measured using a VISCOANALYSER VAR100 manufactured by REOLOGICA INSTRUMENT. The curing time until the viscosity of the sealant after irradiation with ultraviolet rays was 50% of the saturated viscosity value was measured. The saturated viscosity value is a viscosity when the sealing agent is completely cured. It can be determined that the shorter the curing time, the better the curability.

4) Display characteristics of liquid crystal display panel 40 mm × 45 mm glass substrate on which a transparent electrode and an alignment film are formed in advance by using a sealant obtained in Examples and Comparative Examples using a dispenser (shot master: manufactured by Musashi Engineering) 35mm x 40mm square seal pattern (cross-sectional area 3500μm ² ) (main seal) on EHC, RT-DM88-PIN), and similar seal pattern (38mm x 43mm square seal pattern) on the outer periphery And formed.

Next, a liquid crystal material (MLC-119000-000: manufactured by Merck & Co., Inc.) corresponding to the panel internal volume after bonding was precisely dropped into the main seal frame using a dispenser. Next, a pair of glass substrates was bonded together under reduced pressure, and then bonded to the atmosphere. Then, the two bonded glass substrates were held in a light shielding box for 3 minutes, then irradiated with 2000 mJ / cm ² of ultraviolet light, and further heated at 100 ° C. for 1 hour.

  The obtained liquid crystal display panel was visually observed for color unevenness generated in the liquid crystal around the seal part before and after storage in a thermostatic chamber at 70 ° C. and 95% RH for 500 hours. Those in which color unevenness was not confirmed were evaluated as ◯ (excellent); those confirmed were evaluated as x (inferior).

Further, after being stored in the thermostatic chamber, the taken out liquid crystal display panel is driven with an applied voltage of 5 V using a DC power supply device, and the liquid crystal display function in the vicinity of the liquid crystal sealant is functioning normally from the beginning of driving. The display characteristics of the liquid crystal display panel were evaluated.
The display characteristics are ○ (excellent) when the liquid crystal display function can be exhibited normally until sealing, and △ (slightly inferior) when an abnormality in the liquid crystal display function is confirmed at less than 0.3 mm near the sealing. The case where an abnormality in the display function was confirmed at 0.3 mm or more in the vicinity of the seal was defined as x (inferior).

5) Adhesiveness In the above 4), the flat tensile strength of the sample of the liquid crystal display panel after being stored in a thermostat was measured at a tensile speed of 2 m / min using a tensile tester (manufactured by Intesco). Adhesiveness was evaluated as follows.
Adhesive strength of 15 MPa or more: ○ (excellent)
Adhesive strength is 7 MPa or more and less than 15 MPa: Δ (slightly inferior)
Adhesive strength is less than 7 MPa: x (inferior)

The evaluation results of Examples 1 to 3 and Comparative Examples 1 to 5 are shown in Table 2.

  As shown in Table 2, the sealing agents of Examples 1 to 3 using a (meth) acryl-modified epoxy resin having a (meth) acrylic group equivalent weight / epoxy group equivalent ratio of 19 are (meth) acrylic. The N-I point of liquid crystal and the liquid crystal display characteristics are much better than the sealing agents of Comparative Examples 1 to 5 using a (meth) acryl-modified epoxy resin having a ratio of group equivalent / epoxy group equivalent of 9 or less. I understand that. This is because the (meth) acryl-modified epoxy resin contained in the sealing agents of Examples 1 to 3 has a hydroxyl group with respect to the unreacted epoxy group, compared to the (meth) acryl-modified epoxy resin contained in the sealing agents of Comparative Examples 1 to 5. Since the content ratio of is high, it is considered that the solubility in the liquid crystal was remarkably suppressed.

  Moreover, since the (meth) acrylic-modified epoxy resin contained in the sealing agents of Examples 1 to 3 has a higher content of methacrylic groups than the (meth) acrylic-modified epoxy resins of Comparative Examples 1 to 5, it is ultraviolet curable. It turns out that it is also favorable.

  Further, the comparison between Examples 1 and 3 suggests that the sealant containing the solid epoxy resin has high moisture resistance because of high display characteristics after driving. Moreover, it turns out that the sealing agent containing a solid epoxy resin has high adhesiveness.

  This application claims the priority based on Japanese Patent Application No. 2010-072893 of an application on March 26, 2010. The contents described in the application specification and the drawings are all incorporated herein.

Since the liquid crystal sealing agent of the present invention contains many hydroxyl groups, dissolution in liquid crystals is suppressed even at high temperatures and high humidity. For this reason, when the hardened | cured material of the liquid-crystal sealing compound of this invention is applied as a sealing member (liquid crystal sealing part), there is no leak to the sealing member of a liquid crystal, and the liquid crystal panel excellent in display reliability can be provided. For this reason, the liquid-crystal sealing compound of this invention is suitable for manufacture of a liquid crystal display panel.

Claims (10)

A (meth) acryl-modified epoxy resin obtained by reacting an epoxy resin containing two or more epoxy groups in the molecule with (meth) acrylic acid, a thermosetting agent, and a photopolymerization initiator,
The (meth) acryl-modified epoxy resin has a hydrogen-bonding functional group containing a hydroxyl group generated by a reaction between an epoxy resin containing two or more epoxy groups in the molecule and the (meth) acrylic acid, and The (meth) acryl-modified epoxy resin has a (meth) acryl group equivalent / epoxy group equivalent of more than 9,
The hydrogen-bonding functional group value is ^{3 × 10 -3 ~5 × 10 -3} mol / g, the liquid crystal sealant.   The epoxy resin containing two or more epoxy groups in the molecule is a bifunctional epoxy resin selected from the group consisting of a biphenyl type epoxy resin, a naphthalene type epoxy resin, and a bisphenol type epoxy resin. Liquid crystal sealant.   The liquid crystal sealant according to claim 2, wherein the bifunctional epoxy resin is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin.   The liquid crystal sealant according to claim 1, further comprising 1 to 20 parts by weight of a solid epoxy resin having a softening point of 40 ° C or higher and 150 ° C or lower with respect to 100 parts by weight of the liquid crystal sealant.   The liquid crystal seal according to claim 1, wherein the photopolymerization initiator is at least one compound selected from the group consisting of alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, and oxime ester compounds. Agent.   The liquid crystal sealing agent according to claim 1, wherein the thermosetting agent has a melting point of 50 ° C. or higher and 250 ° C. or lower.   The liquid crystal sealant according to claim 1, wherein the thermosetting agent is at least one selected from the group consisting of organic acid dihydrazide compounds, imidazole compounds, dicyandiamide compounds, and polyamine compounds.   The liquid crystal sealing agent according to claim 1, which is used for production of a liquid crystal display panel by a liquid crystal dropping method. Forming a seal pattern on one substrate using the liquid crystal sealant according to claim 1;
Dropping the liquid crystal in the seal pattern region of the one substrate or the other substrate paired with the one substrate in the uncured state of the seal pattern;
A method for manufacturing a liquid crystal display panel, comprising: a step of superimposing the one substrate on the other substrate; and a step of thermally curing the seal pattern after photocuring. A display board;
A counter substrate paired with the display substrate;
A frame-shaped sealing member interposed between the display substrate and the counter substrate;
A liquid crystal display panel including a liquid crystal layer filled in a space surrounded by the seal member between the display substrate and the counter substrate,
The liquid crystal display panel, wherein the seal member is a cured product of the liquid crystal sealant according to claim 1.