WO2020022188A1 - Light-blocking sealing agent for liquid crystal dropping methods and method for producing liquid crystal display panel using same - Google Patents

Abstract

The purpose of the present invention is to provide: a light-blocking sealing agent for liquid crystal dropping methods, which has good photocurability and is capable of reliably sealing the space between substrates of a liquid crystal display panel without causing contamination of liquid crystals; and a method for producing a liquid crystal display panel, which uses this light-blocking sealing agent for liquid crystal dropping methods. A light-blocking sealing agent for liquid crystal dropping methods according to the present invention contains (A) an organic acid, (B) a photocurable resin which has at least one ethylenically unsaturated double bond in each molecule, (C) a titanocene-based photopolymerization initiator, (D) a light blocking agent which has a pH of less than 7.0 or a pH of more than 8.0, (E) a thermosetting compound which has at least one epoxy group in each molecule (excluding the photocurable resin (B)), and (F) a thermal curing agent. With respect to this light-blocking sealing agent for liquid crystal dropping methods, the oxygen atom equivalent of the organic acid (A) is from 23 g/eq to 75 g/eq (inclusive).

Description

Light shielding sealant for liquid crystal dropping method, and method for manufacturing liquid crystal display panel using the same

The present invention relates to a light-shielding sealant for a liquid crystal dropping method and a method for manufacturing a liquid crystal display panel using the same.

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. 2. Description of the Related Art A liquid crystal display panel has a structure in which a liquid crystal material (hereinafter, also simply referred to as “liquid crystal”) is sandwiched between two transparent substrates provided with electrodes on the surface, and the periphery thereof is sealed with a liquid crystal sealant. It is a panel.

(4) Although the amount of the liquid crystal sealant used is small, it is in direct contact with the liquid crystal, which greatly affects the reliability of the liquid crystal display panel. Therefore, in order to achieve high image quality of a liquid crystal display panel, liquid crystal sealants are currently required to have high and various characteristics.

In recent years, a liquid crystal dropping method has been widely used as a method of manufacturing a liquid crystal display panel. 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, and (2) fine liquid crystal is dropped into the frame. Then, (3) a method in which two substrates are overlapped under a high vacuum while the liquid crystal sealant remains uncured, and (4) the liquid crystal sealant is cured to manufacture a panel. In the liquid crystal dropping method, a liquid crystal sealant curable by both light and heat may be used. In this case, in the step (3), after the liquid crystal sealant is temporarily cured by irradiating light such as ultraviolet rays, post-curing by heating can be performed.

で は In the liquid crystal dropping method, the liquid crystal sealant is in contact with the liquid crystal for a long time in an uncured state. Therefore, the components of the liquid crystal sealant are more easily dissolved in the liquid crystal than in the conventional liquid crystal injection method. Therefore, it has been proposed to increase the photocurability by adding an organic acid to the liquid crystal sealant to suppress the contamination of the liquid crystal (Patent Document 1).

On the other hand, cured products of conventional liquid crystal sealants (hereinafter, also referred to as “seal members”) were often colorless or white. However, when such a sealing member protrudes outside a desired region, the light of the backlight leaks from this portion, which may cause a decrease in contrast. Therefore, it has been studied to blacken the obtained seal member by including a light-shielding agent in the liquid crystal sealant (Patent Documents 2 to 4).

International Publication No. WO 2016/065882 JP 2006-99027 A JP 2006-313286 A JP-A-2017-107234

(4) By making the seal member black, for example, a wide wiring or the like can be covered with the seal member, and a color filter can be arranged on the TFT array side. As a result, the degree of freedom in wiring design is widened, and the brightness of the liquid crystal display panel can be increased.

However, when the liquid crystal sealant was blackened, light for curing the liquid crystal sealant was difficult to reach a deep portion, and poor curing was likely to occur. Therefore, it is conceivable to use a photopolymerization initiator having an absorption wavelength up to the longer wavelength side, add a thermal radical generator, or the like to the liquid crystal sealant. However, even with such a method, it is difficult to sufficiently enhance the photocurability of the black liquid crystal sealant, and liquid crystal leakage occurs in the obtained liquid crystal display panel, or the adhesive strength between the substrates is likely to be insufficient. Was.

The present invention has been made in view of the above problems. That is, a light-shielding sealant for a liquid crystal dropping method, which has good photocurability and can reliably seal between liquid crystal display panel substrates without causing contamination of the liquid crystal, and An object of the present invention is to provide a method for manufacturing a liquid crystal display panel.

The present invention provides the following light-shielding sealant for a liquid crystal dropping method.
[1] (A) an organic acid, (B) a photocurable resin having at least one ethylenically unsaturated double bond in one molecule (provided that the (A) organic acid is excluded), and (C) A titanocene-based photopolymerization initiator, (D) a light-shielding agent having a pH of less than 7.0 or more than 8.0, and (E) a thermosetting compound having at least one epoxy group in one molecule (provided that ( B) excluding a photocurable resin) and (F) a thermosetting agent, wherein the (A) organic acid has an oxygen atom equivalent represented by the following formula (1) of 23 g / eq or more and 75 g / eq. The following is a light-shielding sealant for a liquid crystal dropping method.
Oxygen atom equivalent (g / eq) = (molecular weight of organic acid) / (number of oxygen atoms in one molecule of organic acid) (1)

[2] The light-shielding sealant according to [1], which has a blackness of 2 to 5.
[3] The light-shielding sealant according to [1] or [2], wherein the light-shielding agent (D) contains at least one of carbon and titanium.
[4] The organic acid (A) includes, in one molecule, an —OH group, a —NH ₂ group, a —NHR group (R represents an aromatic or aliphatic hydrocarbon or a derivative thereof), a —COOH group, _{-OP (= O) (OH)} 2 group, -P (= O) (OH ) 2 group, -SO ₃ H group, at least one functional group selected from the group consisting of -CONH ₂ groups, and -NHOH group The light-blocking sealant for a liquid crystal dropping method according to any one of [1] to [3].

[5] The light-shielding sealant for a liquid crystal dropping method according to any one of [1] to [4], wherein the photocurable resin (B) further has an epoxy group in a molecule.
[6] The heat curing agent (F) is selected from the group consisting of a dihydrazide heat latent curing agent, an imidazole heat latent curing agent, an amine adduct heat latent curing agent, and a polyamine heat latent curing agent. The light-shielding sealant for a liquid crystal dropping method according to any one of [1] to [5], which is one or more of the following.

The present invention also provides the following method for manufacturing a liquid crystal display panel.
[7] A step of forming a seal pattern on one of the substrates using the light-shielding sealant for a liquid crystal dropping method according to any one of [1] to [6], and In the region of the seal pattern, or a step of dropping liquid crystal on the other substrate paired with the one substrate, and the step of superimposing the one substrate and the other substrate via the seal pattern, And a step of curing the seal pattern.

[8] The method for manufacturing a liquid crystal display panel according to [7], wherein the step of curing the seal pattern includes a step of irradiating the seal pattern with light to cure the seal pattern.
[9] The method for manufacturing a liquid crystal display panel according to [8], wherein the light applied to the seal pattern includes light in a visible light region.
[10] The method for manufacturing a liquid crystal display panel according to [8] or [9], wherein the step of curing the seal pattern further includes a step of heating and curing the seal pattern irradiated with light.

シ ー ル The sealant for the liquid crystal dropping method of the present invention has good photocurability despite containing a light-shielding agent. Further, the liquid crystal dropping method sealing agent is unlikely to contaminate the liquid crystal even when it comes into contact with the liquid crystal. Therefore, according to the liquid crystal dropping method sealing agent, a liquid crystal display panel having excellent display reliability can be obtained.

1. Light-shielding sealant for liquid crystal dropping method The light-shielding sealant for liquid crystal dropping method (hereinafter also simply referred to as “sealant”) of the present invention comprises (A) an organic acid, (B) a photocurable resin, and (C) titanocene. A system photopolymerization initiator, (D) a light-shielding agent, (E) a thermosetting compound, and (F) a thermosetting agent. The sealant may contain other components as necessary.

As described above, in the conventional liquid crystal sealant containing a light-shielding agent, it was difficult to sufficiently harden the inside of the liquid-crystal sealant when the light-shielding agent was added. Therefore, in a liquid crystal display panel manufactured using such a liquid crystal sealant, there is a problem that a liquid crystal leaks easily and an adhesive strength between substrates is apt to be insufficient.

On the other hand, (D) the light-shielding agent contained in the sealant of the present invention has a pH of less than 7 (more specifically, less than 7.0) or a pH of more than 8.0, and the dispersibility of the light-shielding agent is much better. It is. Although the reason is not clear, if (D) the pH of the light-shielding agent is less than 7 (more specifically, less than 7.0) or if the pH is more than 8.0, (D) other light- It is considered that components (for example, (A) an organic acid, (B) a photocurable resin, and (E) a thermosetting compound) interact with each other. As a result, it is considered that (D) the dispersibility of the light-shielding agent is improved. If the dispersibility of (D) the light-shielding agent is low, poor curing is likely to occur in a region where the concentration of the (D) light-shielding agent is high, resulting in uneven curability. On the other hand, when the (D) light-shielding agent is uniformly dispersed in the sealant as in the present invention, the curability of the entire sealant becomes uniform.

シ ー ル The sealant of the present invention contains (A) an organic acid, and the (A) organic acid promotes the photocuring reaction of (B) the photocurable resin. Further, at this time, since the oxygen atom equivalent of (A) the organic acid is within a predetermined range, even if the liquid crystal contacts the (A) organic acid, it hardly affects the liquid crystal.

Furthermore, the sealant of the present invention contains (C) a titanocene-based photopolymerization initiator having an ability to absorb visible light. Light having a relatively long wavelength (for example, visible light) easily reaches the inside of the sealant. Therefore, by using a titanocene-based photopolymerization initiator that can be activated by such long-wavelength light, the deep curability of the sealant can be enhanced.

As described above, the sealant of the present invention has good photocurability even though it contains (D) a light-shielding agent so that its blackness is, for example, 2 to 5. Further, according to the sealing agent, it is possible to reliably seal the space between the substrates of the liquid crystal display panel without causing the liquid crystal to be contaminated by the uncured component.

(A) Organic Acid As described above, when the sealing agent contains (A) the organic acid, the photocurability of the sealing agent is enhanced. In this specification, the organic acid (A) may be a Bronsted acid, and the organic acid (A) includes a compound having an acid anhydride structure.

Here, (A) the organic acid has an oxygen atom equivalent represented by the following formula (1) of 23 g / eq to 75 g / eq, preferably 25 to 60 g / eq, more preferably 27 to 55 g. / Eq.
Oxygen atom equivalent (g / eq) = (molecular weight of organic acid) / (number of oxygen atoms in one molecule of organic acid) (1)

When the oxygen atom equivalent is 23 g / eq or more, the liquid crystal and the organic acid (A) are hardly compatible with each other even when the organic acid (sealant) comes into contact with the liquid crystal during the production of the liquid crystal display panel. The liquid crystal is hardly contaminated. On the other hand, when the oxygen atom equivalent is 75 g / eq or less, even if a small amount of the (A) organic acid is eluted into the liquid crystal, the influence is hardly exerted.

Here, (A) the organic acid includes -OH group, -NH ₂ group, -NHR group (R represents an aromatic or aliphatic hydrocarbon or a derivative thereof), -COOH group, -OP (= O) (OH) ₂ groups, -P (= O) (OH) ₂ groups, -SO ₃ H groups, -CONH ₂ groups, and -NHOH groups. Is preferred. More preferably, it contains a —COOH group or a —OP (＝ O) (OH) ₂ group. When these groups are contained in (A) the organic acid, the (A) organic acid and the liquid crystal are hardly compatible with each other, and the contamination of the liquid crystal is easily suppressed. (A) The organic acid may contain only one kind of these groups, or may contain two or more kinds of these groups.

(A) Examples of organic acids include acetic acid, butyric acid, oxalic acid, citric acid, lauric acid, stearic acid, malonic acid, adipic acid, tartaric acid, benzoic acid, salicylic acid, phthalic acid, monoethyl phosphate, monophenyl phosphate, Diethyl phosphate, mono-2-ethylhexyl phosphate, di (2-ethylhexyl) phosphate, benzenesulfonic acid, toluenesulfonic acid, sulfobenzoic acid, formic acid, propionic acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargon Acid, capric acid, myristic acid, palmitic acid, margaric acid, succinic acid, glutaric acid, dodecane diacid, sepasic acid, isophthalic acid, terephthalic acid, benzenetricarboxylic acid (including isomers), pyromellitic acid, melitic acid, 4 -(4-hydroxyphenyl) benzoic acid, 6-hydroxy-1-naphthoic acid, (A) Organic acid having no ethylenically unsaturated double bond in one molecule, such as fonic acid, glycolic acid, trimellitic acid, trimellitic anhydride, 4'-hydroxy-4-biphenylcarboxylic acid It is.

Examples of the organic acid (A) having no ethylenically unsaturated double bond in one molecule include a compound represented by the following formula.

The organic acid (A) may contain an ethylenically unsaturated double bond in the molecule. (A) When at least one unsaturated double bond is contained in one molecule of the organic acid, the (A) organic acid is polymerized with the (B) photocurable resin, and the cured product of the sealant is converted into the (A) organic acid. Is difficult to exude. (A) The number of unsaturated double bonds contained in one molecule of the organic acid may be two or more.

Examples of the (A) organic acid having an unsaturated double bond in one molecule include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, 2- (meth) acryloyloxyethyl succinic acid, 2- ( (Meth) acryloyloxyethyl phthalic acid, bisphenol A type epoxy (meth) acrylate acid anhydride modified compound, bisphenol A type epoxy (meth) acrylate phosphoric acid modified compound, bisphenol F type epoxy (meth) acrylate acid anhydride modified Compounds, phosphoric acid-modified compounds of bisphenol F type epoxy acrylate, phosphoric acid (meth) acrylates, and high molecular weights thereof are included. In addition, (meth) acryl means either or both of acryl and methacryl.

Examples of the above-mentioned phosphoric acid (meth) acrylates include [CH ₂ = CRCOOCH ₂ CH ₂ [OCO (CH ₂ ) ₆ ] _a O] _b PO (OH) _3-b (R is a hydrogen atom or a methyl group. A represents 0 to 2, b represents 1 or 2), or [CH ₂ ＣＲCRCOOCH ₂ CH ₂ [OCH ₂ CH (CH ₃ )] _c O] _d PO (OH) _3-e ( R represents a hydrogen atom or a methyl group, d represents 0 to 2, and c and e represent 1 or 2).

Among the above, the preferred organic acids (A) include oxalic acid, tartaric acid, trimellitic acid, trimellitic anhydride, isophthalic acid, phenylphosphonic acid, 4'-hydroxy-4-biphenylcarboxylic acid, terephthalic acid, and succinic acid , And glutaric acid.

The preferred molecular weight of the organic acid (A) is from 60 to 5,000, more preferably from 60 to 3,000, even more preferably from 100 to 1500. When the molecular weight of (A) the organic acid is within the above range, the (A) organic acid easily flows inside the sealant, and photocuring of the sealant is easily promoted.

(4) The content of the organic acid (A) is 0.01 to 20 parts by mass, preferably 0.05 to 10 parts by mass, based on 100 parts by mass of the sealant. When the (A) organic acid is included in the above range, the photocurability of the sealant is easily increased, and the liquid crystal is less likely to be contaminated by the (A) organic acid.

(B) Photocurable resin (B) The photocurable resin is not particularly limited as long as it has at least one ethylenically unsaturated double bond in one molecule. However, in this specification, (B) the photocurable resin does not include the compound corresponding to the (A) organic acid. (B) Examples of the photocurable resin include (B1) a (meth) acrylic resin and (B2) a (meth) acryl-modified epoxy having at least one epoxy group and one (meth) acryl group in one molecule. Resin included.

(4) When the photocurable resin is (B1) (meth) acrylic resin or (B2) (meth) acrylic modified epoxy resin, the photocurability of the sealant is easily increased sufficiently. In particular, when the photocurable resin is (B2) (meth) acryl-modified epoxy resin, the moisture resistance of the cured product of the sealant tends to increase. The sealant of the present invention may include both (B1) (meth) acrylic resin and (B2) (meth) acryl-modified epoxy resin.

(B1) The (meth) acrylic resin is a compound containing one or more (meth) acrylic groups in one molecule, and is a compound containing no epoxy group. (B1) Examples of the (meth) acrylic resin include diacrylates and / or dimethacrylates such as polyethylene glycol, propylene glycol, and polypropylene glycol; diacrylates and / or dimethacrylates of tris (2-hydroxyethyl) isocyanurate; Diacrylate and / or dimethacrylate of diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of pentyl glycol; diacrylate of diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A; / Or dimethacrylate; diol of triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane. Or triacrylate and / or di or trimethacrylate; diacrylate and / or dimethacrylate of a diol obtained by adding at least 4 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A; tris (2-hydroxyethyl) isocyanurate triacrylate; Trimethylolpropane triacrylate and / or trimethacrylate, or an oligomer thereof; pentaerythritol triacrylate and / or trimethacrylate, or an oligomer thereof; polyacrylate and / or polymethacrylate of dipentaerythritol; tris (acryloxy) Ethyl) isocyanurate; caprolactone-modified tris (acryloxyethyl) isocyanate Nurate; caprolactone-modified tris (methacryloxyethyl) isocyanurate; alkyl-modified dipentaerythritol polyacrylate and / or polymethacrylate; caprolactone-modified dipentaerythritol polyacrylate and / or polymethacrylate; hydroxypivalate neopentyl glycol diacrylate and And / or dimethacrylate; caprolactone-modified neopentyl glycol hydroxypivalate diacrylate and / or dimethacrylate; ethylene oxide-modified phosphate acrylate and / or dimethacrylate; ethylene oxide-modified alkylated phosphate acrylate and / or dimethacrylate; neopentyl glycol , Trimethylolpropane, Pentaerythrit Oligoacrylate and / or oligomethacrylate.

(B1) The weight average molecular weight of the (meth) acrylic resin can be, for example, about 310 to 1,000. (B1) The weight average molecular weight Mw of the (meth) acrylic resin can be measured by gel permeation chromatography (GPC) using polystyrene as a standard.

The amount of the (B1) (meth) acrylic resin in the sealant is 5 to 80 parts by mass with respect to 100 parts by mass of the sealant, depending on the curability required for the sealant and its blackness. And more preferably 10 to 80 parts by mass.

On the other hand, the (B2) (meth) acryl-modified epoxy resin is a compound containing at least one each of a (meth) acryl group and an epoxy group. Preferably, the epoxy resin and the (meth) acrylic acid are tertiary, for example. It is a compound obtained by reacting in the presence of a basic catalyst such as an amine.

(B2) 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. Further, the (meth) acryl-modified epoxy resin has low solubility in liquid crystal, and hardly affects the liquid crystal.

(B2) The epoxy resin used as a raw material of the (meth) acryl-modified epoxy resin may be a bifunctional or higher epoxy resin having two or more epoxy groups in a molecule. Examples thereof include bisphenol A type and bisphenol F. Type, 2,2'-diallylbisphenol A type, bisphenol AD type, bisphenol type epoxy resin such as hydrogenated bisphenol type; novolak type epoxy such as phenol novolak type, cresol novolak type, biphenyl novolak type, and trisphenol novolak type Resin; biphenyl type epoxy resin; naphthalene type epoxy resin and the like. A (meth) acryl-modified epoxy resin obtained by modifying a trifunctional or tetrafunctional polyfunctional epoxy resin with a (meth) acrylic resin has a high crosslinking density and a low adhesion strength to a substrate. Therefore, the epoxy resin used as the raw material of the (B2) (meth) acryl-modified epoxy resin is preferably a bifunctional epoxy resin.

Particularly, the bifunctional epoxy resin is preferably a biphenyl type epoxy resin, a naphthalene type epoxy resin, and a bisphenol type epoxy resin. Among them, bisphenol type epoxy resins such as bisphenol A type and bisphenol F type are preferably used as a sealing agent. It is preferable from the viewpoint of the applicability and the like.

エ ポ キ シ Epoxy resin as a raw material may be only one kind, or two or more kinds may be combined. Further, it is preferable that the epoxy resin as a raw material is highly purified by a molecular distillation method, a washing method, or the like.

Here, (B2) the (meth) acryl-modified epoxy resin is preferably one in which 10 to 99.5% of the epoxy groups of the epoxy resin as a raw material are modified with (meth) acryl groups, and 30 to 95% % Is more preferably modified with an acrylic group. When the epoxy group is modified in the above range with a (meth) acrylic group, the photocurability and the thermosetting property of the sealant are improved, and the moisture resistance of the cured product of the sealant is likely to be lowered.

重量 (B2) The weight average molecular weight of the (meth) acryl-modified epoxy resin can be, for example, about 310 to 1,000. (B2) The weight average molecular weight Mw of the (meth) acryl-modified epoxy resin can be measured, for example, by gel permeation chromatography (GPC) using polystyrene as a standard.

The amount of the (B2) (meth) acryl-modified epoxy resin in the sealing agent depends on the degree of curability required, but is preferably 5 to 80 parts by mass, and preferably 10 to 80 parts by mass, per 100 parts by mass of the sealing agent. More preferably, it is 80 parts by mass.

Here, (B) the photocurable resin preferably has a hydrogen-bonding functional group such as a hydroxyl group, a urethane bond, an amide group, and a carboxyl group in the molecule. These groups may be, for example, hydroxyl groups generated by reacting an epoxy group of an epoxy resin with (meth) acrylic acid, and a compound (B) as a raw material of a photocurable resin (for example, (meth) acrylic acid Or an epoxy resin), or a urethane bond, a carboxyl group, an amide group, or the like contained in a compound as a raw material.

(B) If the photocurable resin has a hydrogen-bonding functional group, the compatibility with the hydrophobic liquid crystal material is reduced, and the dissolution in the liquid crystal is suppressed. As a result, a sealant suitable for the liquid crystal dropping method is easily obtained.

(B) The equivalent of the hydrogen bonding functional group contained in the photocurable resin is preferably from 1.0 × 10 ⁻⁴ to 5 × 10 ⁻³ mol / g, and preferably from 3.5 × 10 ⁻³ to 4. More preferably, it is 5 × 10 ⁻³ mol / g. When the hydrogen-bonding functional group equivalent is 1.0 × 10 ⁻⁴ mol / g or more, the dissolution of the photocurable resin (B) in the liquid crystal is easily suppressed. On the other hand, when the hydrogen bonding functional group equivalent is 5 × 10 ⁻³ mol / g or less, the cured product of (B) the photocurable resin tends to have sufficient moisture resistance, and the cured product of the sealant has moisture resistance. Is not easily reduced.

(B) The hydrogen-bonding functional group equivalent (mol / g) of the photocurable resin is represented by "(B) Number of hydrogen-bonding functional groups contained in one molecule of photocurable resin" / "(B) Photocurable Weight average molecular weight (Mw) of the resin ". For example, when only a hydroxyl group obtained by reacting (meth) acrylic acid with an epoxy resin is used as the hydrogen bonding functional group, the hydrogen bonding functional group equivalent is determined by the number of moles of the reacted (meth) acrylic acid. , (Meth) acrylic modified epoxy resin by weight average molecular weight (Mw).

Here, when the (B) photo-curable resin is the above-mentioned (B1) (meth) acrylic resin, the hydrogen-bonding functional group equivalent is such that the monomer for obtaining the (B1) (meth) acrylic resin is It can be controlled by adjusting the amount of the hydrogen-bonding functional group contained. On the other hand, when the (B) photo-curable resin is the above-mentioned (B2) (meth) acryl-modified epoxy resin, its hydrogen-bonding functional group equivalent is determined, for example, by reacting (meth) acrylic acid with the epoxy resin as a raw material. Can be controlled by adjusting the number of moles, or by adjusting the amount of hydrogen-bonding functional groups contained in the raw material (meth) acrylic acid or epoxy resin.

The total amount of (B) the photocurable resin (for example, the total amount of (B1) (meth) acrylic resin and (B2) (meth) acryl-modified epoxy resin) is 5 to 80 parts by mass with respect to 100 parts by mass of the sealant. And more preferably 10 to 80 parts by mass.

(C) Titanocene-based photopolymerization initiator The (C) titanocene-based photopolymerization initiator contained in the sealant of the present invention is a compound for curing the (B) photocurable resin described above. As described above, since the (C) titanocene-based photopolymerization initiator has a visible light absorbing ability, the use of the (C) titanocene-based photopolymerization initiator can enhance the deep curability of the sealant. Becomes

(C) Examples of titanocene-based photopolymerization initiators include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl)- Phenyl) titanium, bis (cyclopentadienyl) -dichlorotitanium, bis (cyclopentadienyl) -diphenyltitanium, bis (cyclopentadienyl) -bis (2,3,4,5,6 pentafluorophenyl) titanium , Bis (cyclopentadienyl) -bis (2,6 difluorophenyl) titanium, bis (methylcyclopentadienyl) -bis (2,3,4,5,6 pentafluorophenyl) titanium, bis (methylcyclopenta Dienyl) -bis (2,6-difluorophenyl) titanium, bis (cyclopentadienyl) -bis [2,6-diph Oro-3- (2- (1-pyr-1-yl) ethyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3-((1-pyr-1-yl) Methyl) phenyl] titanium, bis (methylcyclopentadienyl) -bis [2,6-difluoro-3-((1-pyr-1-yl) methyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3-((2,5-dimethyl-1-pyr-1-yl) methyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3- ( (3-trimethylsilyl-2,5-dimethyl-1-pyr-1-yl) methyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3-((2,5-bis ( Morpholinomethyl) -1-pyr-1-yl) methyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-4-((2,5-dimethyl-1-pyr-1- Yl) methyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3-methyl-4- (2- (1-pyr-1-yl) ethyl) phenyl] titanium, bis ( Cyclopentadienyl) -bis [2,6-difluoro-3- (1-methyl-2- (1-pyr-1-yl) ethyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2 6-difluoro-3- (6- (9-carbazol-9-yl) hexyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3- (3- (4,5, 6 7-tetrahydro-2-methyl-1-indol-1-yl) propyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3-((acetylamino) methyl) phenyl] titanium , Bis (cyclopentadienyl) -bis [2,6-difluoro-3- (2- (propionylamino) ethyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3- (4- (Bivaloylamino) butyl) phenyl] titanium, bis (cyclopentadienyl) -bis [2,6-difluoro-3- (2- (2,2-dimethylpentanoylamino) ethyl) phenyl] titanium , Bis (cyclopentadienyl) -bis [2,6-difluoro-3- (3- (benzoylamino) propyl) phenyl Le] titanium, bis (cyclopentadienyl) - include bis [2,6-difluoro-3-(2-(N-allyl-methylsulfonylamino)) phenyl] titanium and the like. The sealing agent may contain only one kind of the (C) titanocene-based photopolymerization initiator, or may contain two or more kinds.

中 で も Among the above, it is preferable to be able to absorb light having a wavelength of 300 to 550 nm, and more preferably to be able to absorb light having a wavelength of 350 to 500 nm.

The content of the titanocene photopolymerization initiator (C) is 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the sealant. When the sealing agent contains (C) the titanocene-based photopolymerization initiator in the above range, the photocurability of the sealing agent is likely to increase.

(D) Light-Shielding Agent The light-shielding agent contained in the sealant of the present invention has a pH of less than 7 (specifically, less than 7.0) or a pH of more than 8.0 and a blackness of the sealant of, for example, 2 to 5 There is no particular limitation as long as it is adjustable. When the pH of (D) the light-shielding agent is less than 7 (specifically, less than 7.0) or the pH is more than 8.0, the dispersibility of (D) the light-shielding agent in the sealant is excellent as described above. And the curability of the sealant is improved.

(D) The pH of the light-shielding agent was determined by diluting and stirring the (D) light-shielding agent 20-fold with pure water, and then measuring the pH of the pure water containing the (D) light-shielding agent with a compact pH meter (B-71X manufactured by HORIBA). It can be obtained by measuring. (D) When the pH of the light-shielding agent is less than 7.0, it is preferably from 1 to 6, more preferably from 1 to 4. On the other hand, when the pH of the light-shielding agent (D) exceeds 8.0, the pH is preferably 10.0 or less.

例 Examples of the (D) light-blocking agent satisfying the above-mentioned pH include carbon black, titanium black, vanadium, and inorganic compounds such as iron and copper. Among these, it is preferable to include carbon, and examples thereof include acidic carbon black. The acidic carbon black may be a channel black or an oxidized carbon black. Examples of the method of oxidizing carbon black include air oxidation, nitric acid, mixed gas of nitrogen oxide and air, and oxidation with various oxidizing agents such as ozone. The sealing agent may contain only one type of (D) light-shielding agent, or two or more types. Examples of preferable (D) light-shielding agents also include titanium black.

(D) The shape of the light-shielding agent is not particularly limited, and may be a fixed shape such as a sphere, a plate, or a needle, or an irregular shape. The average primary particle diameter of the light-shielding agent (D) is preferably 0.005 to 0.1 μm, more preferably 0.01 to 0.05 μm, and more preferably 0.015 to 0.03 μm. Is more preferable. Average particle diameter It can be measured by a laser diffraction method described in JIS Z8825. The specific surface area can be measured by the BET method described in JIS Z8830.

量 The amount of the (D) light-shielding agent with respect to 100 parts by mass of the sealing agent is not particularly limited as long as the blackness of the sealing agent can be adjusted to, for example, 2 to 5. For example, the amount can be 5 to 46 parts by mass, preferably 7 to 40 parts by mass, and more preferably 10 to 30 parts by mass with respect to the total amount of the sealant. (D) When the amount of the light-shielding agent is within the above range, the blackness of the sealing agent tends to fall within a desired range. On the other hand, if the amount of the (D) light-shielding agent is excessively large, the (D) light-shielding agent is likely to aggregate, and the photocurability of the sealant is likely to be reduced.

(E) Thermosetting Compound The sealant of the present invention contains (E) a thermosetting compound having at least one epoxy group in one molecule. When the sealant contains (E) a thermosetting compound, the cured product of the sealant has improved moisture resistance. In this specification, a resin corresponding to the above-mentioned (B) photocurable resin is not included in (E) the thermosetting compound. (E) The number of epoxy groups contained in the thermosetting compound is preferably two or more, and particularly preferably two.

(E) Examples of the thermosetting compound include bisphenol type epoxy resins such as bisphenol A type, bisphenol F type, bisphenol S type, 2,2′-diallylbisphenol A type, bisphenol AD type, and hydrogenated bisphenol type; Diphenyl ether type epoxy resin; phenol novolak type, cresol novolak type, biphenyl novolak type, bisphenol novolak type, naphthol novolak type, trisphenol novolak type, dicyclopentadiene novolak type, etc .; nophenyl type epoxy resin; biphenyl type epoxy resin; naphthyl type epoxy resin Resins; triphenol alkane type epoxy resins such as triphenol methane type, triphenol ethane type, and triphenol propane type; alicyclic epoxy resins. Among them, bisphenol type epoxy resins such as bisphenol A type and bisphenol F type are preferable. These bisphenol-type epoxy resins have advantages such as lower crystallinity and superior coating stability than diphenyl ether-type epoxy resins and the like. In addition, the compound has low solubility and diffusibility in liquid crystal, and not only improves the display characteristics of the obtained liquid crystal display panel, but also increases the moisture resistance of the cured product of the sealant.

重量 (E) The thermosetting compound preferably has a weight average molecular weight (Mw) of 300 to 3,000, more preferably 300 to 2,000. (E) The weight average molecular weight of the thermosetting compound can be measured, for example, by gel permeation chromatography (GPC) using polystyrene as a standard. (E) The thermosetting compound may be liquid or solid. (E) When the thermosetting compound is a solid epoxy resin, the softening point is preferably from 40 ° C to 150 ° C.

The sealant may contain only one kind of the thermosetting compound (E), or may contain two or more kinds having different kinds and molecular weights. The amount of the thermosetting compound (E) is 5 to 70 parts by mass, preferably 5 to 50 parts by mass, based on 100 parts by mass of the sealant. By including the (E) thermosetting compound in the above range, the moisture resistance of the cured product of the sealant is easily increased.

(F) Thermosetting agent The sealant of the present invention contains (F) a thermosetting agent. The (F) thermosetting agent is a compound that contributes to the reaction of the epoxy group contained in the (E) thermosetting compound. When the photocurable resin (B) has an epoxy group, it also contributes to the reaction of the epoxy group. In the present specification, those that do not generate radicals when reacting with an epoxy group are referred to as (F) thermosetting agents.

Ｆ (F) The type of the thermosetting agent is not particularly limited, but is preferably a thermal latent curing agent. The thermal latent curing agent is a compound which does not cure the (E) thermosetting compound during storage of the sealant (at room temperature), and contributes to the reaction of the epoxy group of the (E) thermosetting compound by heating, (E) A compound that cures a thermosetting compound.

A known compound can be used as the heat latent curing agent, but a heat latent curing agent having a melting point of 50 ° C. or more and 250 ° C. or less is preferable in order to increase the viscosity stability of the sealant. Further, from the viewpoint of curing the resin even at a low thermosetting temperature (about 80 to 100 ° C.), the melting point is more preferably 50 ° C. or more and 200 ° C. or less.

Preferred examples of the heat latent curing agent include a dihydrazide heat latent curing agent, an imidazole heat latent curing agent, an amine adduct heat latent curing agent, and a polyamine heat latent curing agent.

Examples of dihydrazide heat latent curing agents include adipic dihydrazide (melting point: 181 ° C.), 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (melting point: 120 ° C.), 7,11-octadecadien Includes -1,18-dicarbohydrazide (melting point 160 ° C.), dodecane diacid dihydrazide (melting point 190 ° C.), sebacic acid dihydrazide (melting point 189 ° C.), and the like.

Preferred examples of the imidazole heat latent curing agent include a compound having a structure represented by the following general formula (X).

In the general formula (X), R ₁ and R ₂ are each independently a hydrogen atom, a lower alkyl group, a lower hydroxyalkyl group, a phenyl group or a benzyl group. R ₃ and R ₄ are each independently a hydrogen atom, a lower alkyl group or a lower hydroxyalkyl group. At least one of R ₁ to R ₄ is a lower hydroxyalkyl group. Since the imidazole-based latent heat curing agent having a lower hydroxyalkyl group contains a hydroxyl group, it is difficult to dissolve in a liquid crystal.

The lower alkyl group which may be R ₁ to R ₄ in the above formula (X) is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, and a propyl group, and is preferably a methyl group or an ethyl group. On the other hand, the lower hydroxyalkyl group is a hydroxyalkyl group having 1 to 4 carbon atoms such as a hydroxymethyl group and a hydroxyethyl group, and is preferably a hydroxymethyl group. The lower hydroxyalkyl group may include a plurality of hydroxyl groups.

The number of hydroxyl groups contained in the imidazole-based curing catalyst is not particularly limited, but since the water resistance may decrease when the number of hydroxyl groups is 2 or more, the number of hydroxyl groups is 1 in terms of not reducing water resistance and the like. Preferably, there is.

The melting point of the imidazole heat latent curing agent represented by the general formula (X) depends on the heat curing temperature of the sealant, but when the sealant is thermoset at a relatively low temperature (for example, about 80 to 100 ° C.). Is preferably 150 ° C. or lower, more preferably 120 ° C. or lower, still more preferably 60 to 120 ° C., and particularly preferably 80 to 100 ° C. If the melting point of the imidazole heat latent curing agent is too low, the imidazole heat latent curing agent will melt at room temperature. Then, (E) the curing reaction of the thermosetting compound proceeds, and the storage stability of the sealant at room temperature deteriorates. On the other hand, if the melting point is too high, it becomes difficult for the imidazole-based heat latent curing agent to exert its catalytic function sufficiently at the thermosetting temperature of the sealant. The melting point of the imidazole heat latent curing agent can be lowered by, for example, having a structure not containing an aromatic ring.

From the viewpoint of lowering the melting point of the imidazole heat latent curing agent, R ₂ is preferably a group other than a phenyl group or a benzyl group, that is, a hydrogen atom, a lower alkyl group or a lower hydroxyalkyl group, and a lower hydroxyalkyl group. Is more preferable.

Examples of the imidazole heat latent curing agent represented by the general formula (X) include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-hydroxy Methyl imidazole, 1-benzyl-5-hydroxymethyl imidazole, 1,2-dihydroxyethyl imidazole and the like are included. Among the above, examples of the imidazole-based heat latent curing agent having a melting point of 150 ° C. or lower include 2-hydroxymethylimidazole.

(4) The amine adduct thermal latent curing agent is an additional compound obtained by reacting an amine compound having catalytic activity with an arbitrary compound. In such an amine adduct thermal latent curing agent, the amine is dissociated by heat and activated. Examples of the amine-based compound include compounds having 1, 2, and tertiary amino groups, such as Amicure PN-40 (melting point 110 ° C.), Amicure PN-23 (melting point 100 ° C.), and Amicure PN-31 ( Melting point 115 ° C.), AMICURE PN-24 (melting point 115 ° C.), AMICURE MY-24 (melting point 120 ° C.), AMICURE MY-H (melting point 130 ° C.) (all manufactured by Ajinomoto Fine Techno Co., Ltd.) and the like.

The polyamine-based heat latent curing agent is a heat latent curing agent having a polymer structure obtained by reacting an amine with an epoxy, and specific examples thereof include Adeka Hardener EH4339S (softening point of 120 to 130) manufactured by ADEKA Corporation. ° C) and Adeka Hardener EH4357S (softening point 73-83 ° C) manufactured by ADEKA Corporation.

The content of the thermosetting agent (F) is preferably 5 to 100 parts by mass, more preferably 10 to 100 parts by mass, based on 100 parts by mass of the total of (B) the photocurable resin and (E) the thermosetting compound. It is 50 parts by mass or less. (F) When a thermosetting agent is contained, the thermosetting reaction of the sealing agent easily proceeds sufficiently.

(G) Others The sealant of the present invention may contain components other than those described above. Examples of other components include inorganic fillers and organic fillers, various additives, and the like.

(4) When the sealant contains an inorganic filler, the viscosity of the sealant can be adjusted to a desired range, and the strength and linear expansion of a cured product of the sealant can be controlled. Examples of the inorganic filler include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, aluminum oxide (alumina), zinc oxide, silicon dioxide, potassium titanate, kaolin, and talc. , Glass beads, sericite activated clay, bentonite, aluminum nitride, silicon nitride, titanium nitride and the like, and preferably silicon dioxide and talc. The sealant may include only one of these, or may include two or more thereof.

The shape of the inorganic filler is not particularly limited, and may be any of a fixed shape such as a sphere, a plate, and a needle, or an irregular shape. The inorganic filler preferably has an average primary particle diameter of 1.5 μm or less, and preferably has a specific surface area of 1 m ² / g to 500 m ² / g. The average primary particle diameter of the inorganic filler can be measured by a laser diffraction method described in JIS Z8825. The specific surface area can be measured by the BET method described in JIS Z8830.

量 The amount of the inorganic filler is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, based on 100 parts by mass of the sealant.

On the other hand, when the sealant contains an organic filler, the impact resistance and the like of the sealant are improved. The type of the organic filler is not particularly limited, but the melting point of the sealant is preferably higher than the thermosetting temperature. On the other hand, if the softening point of the organic filler is too high, the organic filler becomes difficult to deform. Therefore, the softening point of the organic filler is preferably 30 to 120 ° C.

Examples of the organic filler include fine particles selected from the group consisting of silicone fine particles, acrylic fine particles, styrene fine particles such as styrene-divinylbenzene copolymer, and polyolefin fine particles. The sealant may contain only one type of organic filler, or may contain two or more types of organic filler.

形状 The shape of the organic filler is not particularly limited, and may be, for example, spherical. The average particle size of the organic filler is preferably 0.05 to 5 μm, more preferably 0.07 to 3 μm, since the gap of the liquid crystal cell is usually 5 μm or less. The average particle size of the organic filler can be measured, for example, by a laser diffraction method described in JIS Z8825.

量 The amount of the organic filler is preferably 30 parts by mass or less, more preferably 15 parts by mass or less, based on 100 parts by mass of the sealant.

Examples of various additives include 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, a plasticizer, a defoaming agent, and the like. Further, a spacer or the like may be blended for adjusting the gap of the liquid crystal display panel. These contents are not particularly limited as long as the objects and effects of the present invention are not impaired.

-Physical properties of sealant and manufacturing method The above-mentioned sealant preferably has a blackness of 2 to 5, more preferably 3 to 4. The blackness of the sealant can be measured as follows.

First, about 10 μl of a sealing agent is collected with a spatula, and dropped on a 25 mm × 45 mm × 5 mm thick non-alkali glass to form a circle having a diameter of 5 mm. Then, a pair of non-alkali glass is attached so as to overlap with each other and fixed with a jig. The test piece fixed with the jig is irradiated with an ultraviolet ray of 500 mW / cm ² from an ultraviolet ray irradiation device (manufactured by Ushio Inc.) to cure the sealant. At this time, the illuminance energy of the ultraviolet light is 3.0 J / cm ² . The test piece cured by light is heated in an oven at 120 ° C. for 60 minutes to obtain a sample for measuring blackness. Then, the transmittance (% T) of the cured product of the sealant is measured using an ultraviolet-visible spectrophotometer (UV-2550, manufactured by Shimadzu Corporation). Then, using the transmittance (% T) at a wavelength of 500 nm, the blackness (OD value) is calculated by converting the density based on the formula: OD value = -log (% T / 100).

The viscosity of the sealant at 25 ° C. and 2.5 rpm using an E-type viscometer is preferably 30 to 350 Pa · s. A liquid crystal sealant having a viscosity in the above range has excellent coating stability.

The method for producing the above-mentioned sealant is not particularly limited, and all the components may be mixed, or the components may be mixed twice or more. The mixing method is not particularly limited, but is preferably a method capable of sufficiently dispersing the (D) light-shielding agent, such as a three-roll mill.

2. Liquid crystal display panel manufacturing method The liquid crystal display panel is usually a display substrate, a counter substrate to be paired with the display substrate, a frame-shaped sealing member interposed between the display substrate and the counter substrate, a display substrate and the counter substrate. And a liquid crystal layer filled in a space surrounded by the seal member. In the present invention, a cured product of the above-described sealant 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.

マ ト リ ッ ク ス On the surface of the display substrate or the counter substrate, a matrix-like TFT, color filter, black matrix, and the like are arranged. An alignment film is further formed on the surface of the display substrate or the counter substrate. The alignment film contains a known organic or inorganic alignment agent. In the liquid crystal display panel, a black matrix and a color filter may be arranged on a display substrate side, a black matrix may be arranged on a display substrate side, and a color filter may be arranged on a counter substrate side. A black matrix and a color filter may be arranged on the substrate side.

Such a liquid crystal display panel can be manufactured by the following method. Specifically, 1) a first step of applying the above-mentioned sealant to one substrate to form a liquid crystal seal pattern, and 2) the liquid crystal in a state where the liquid crystal seal pattern made of the sealant is uncured. A second step of dropping liquid crystal on a region surrounded by a seal pattern or a region of the other substrate facing the region surrounded by the liquid crystal seal pattern; 3) forming one substrate and the other substrate , A third step of superimposing via a liquid crystal seal pattern, and 4) a fourth step of curing the sealant.

で In the first step, the above-mentioned sealant is applied in a desired pattern. The method for applying the sealant is not particularly limited as long as the sealant can be applied to a desired region, and may be, for example, an application using a dispenser. Further, the liquid crystal seal pattern to be manufactured is appropriately selected according to the type of the liquid crystal display panel and the like, and can be usually formed in a rectangular frame shape or the like.

The line width of the sealant in the liquid crystal seal pattern is preferably 300 to 2000 μm, more preferably 500 to 1500 μm. Sectional area of the sealing agent is preferably 1000 ~ 10000 ^2, more preferably 1500 ~ 5000μm ^2. By setting the line width and the cross-sectional area of the sealant within the above ranges, it is possible to sufficiently cure the inside of the sealant in the fourth step. Then, liquid crystal leakage or the like from the liquid crystal display panel is less likely to occur, and the adhesive strength between the substrates is likely to be sufficient.

{Circle around (2)} In the second step, liquid crystal is applied in a state where the liquid crystal seal pattern produced in the first step is in an uncured state. The method of dropping the liquid crystal is not particularly limited, and may be a known method. The “state in which the liquid crystal seal pattern is not cured” means a state in which the curing reaction of the sealant has not progressed to the gel point. Therefore, in the second step, the liquid crystal seal pattern may be semi-cured by irradiating or heating the liquid crystal in order to suppress the dissolution of the sealant into the liquid crystal.

On the other hand, in the third step, one substrate and the other substrate are overlapped via a liquid crystal seal pattern. The superposition can be performed by a known method, and is usually performed under a high vacuum.

Then, in a fourth step, the sealant is cured. It is preferable that the sealing agent is cured by heating (main curing) after being subjected to light curing (temporary curing). By instantly curing the sealant by temporary curing by light irradiation, dissolution in liquid crystal can be suppressed.

Energy of light illuminating the sealant when temporarily curing is preferably 1000 ~ 3000mJ / cm ² or so, more preferably 1000 ~ 2000mJ / cm ² approximately. Further, the sealant of the present invention contains (C) a titanocene-based photopolymerization initiator. Therefore, the irradiation light preferably includes not only ultraviolet light but also light in the visible light region. In this specification, the visible light region refers to a wavelength range from 360 nm to 800 nm. The light source is not particularly limited, but is preferably an LED, a metal halide lamp, a high-pressure mercury lamp, or a low-pressure mercury lamp, and more preferably an LED or a metal halide lamp. From the viewpoint of sufficiently activating the (C) titanocene-based photopolymerization initiator, the wavelength preferably ranges from 360 to 550 nm, and more preferably ranges from 360 to 450 nm.

On the other hand, the heating temperature at the time of heating after light irradiation depends on the composition of the sealing agent, but is preferably as low as possible, for example, about 120 ° C., from the viewpoint of reducing deterioration of the liquid crystal. The temperature is more preferably 80 to 120 ° C. The heat curing time is about 1 to 2 hours.

実 施 Examples of the present invention will be specifically described below, but the present invention is not limited to these examples. Therefore, the material, the manufacturing method, and the like can be appropriately changed without departing from the present invention.

[Synthesis example]
-Synthesis of methacrylic acid-modified bisphenol F type epoxy resin 160 g of liquid bisphenol F type epoxy resin (Epototo YDF-8170C manufactured by Toto Kasei Co., Ltd., epoxy equivalent 160 g / eq), 0.1 g of p-methoxyphenol as a polymerization inhibitor, catalyst Was charged into a flask, and dry air was fed thereinto, and the mixture was reacted at 90 ° C. for 5 hours while stirring under reflux. The obtained compound was washed 20 times with ultrapure water, and a methacrylic acid-modified bisphenol F-type epoxy resin (95% partially methacrylated) (weight average molecular weight (Mw) 485, hydrogen bonding functional group equivalent 4.0 ×). 10 ⁻³ mol / g).

[Example 1]
(B) As a photocurable resin, 330 parts by mass of a methacrylic acid-modified bisphenol F type epoxy resin obtained in a synthesis example and polyethylene glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd .: light acrylate 14EG-A, weight average molecular weight 722, hydrogen bonding) 172 parts by mass of a functional group equivalent (0.9 × 10 ⁻³ mol / g), 6 parts by mass of (A) trimellitic acid (manufactured by Tokyo Chemical Industry Co., Ltd., oxygen atom equivalent 35 g / eq) as an organic acid, and (C) ) 12 parts by mass of a titanocene-based photopolymerization initiator (manufactured by Insight High Technology: IHT-PI 784) and (E) an epoxy resin as a thermosetting compound (manufactured by Mitsubishi Chemical Corporation: jER1004, softening point 97 ° C, weight average molecular weight) 1650) 50 parts by mass, and (F) adipic dihydrazide (manufactured by Nippon Kasei Co., Ltd.) as a thermosetting agent : ADH, melting point: 177 to 184 ° C) 90 parts by mass, silica particles (S-100 manufactured by Nippon Shokubai Kagaku Co., Ltd .: 80 parts by mass), and thermoplastic resin particles (fine particle polymer, manufactured by Aika Kogyo Co., Ltd .: F351) 40 parts by mass And 20 parts by mass of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-403) and (D) 200 parts by mass of carbon (manufactured by Mitsubishi Chemical Corporation: MA-100R, pH 3.5, particle diameter 24 nm) as a light shielding agent Was thoroughly mixed using a three-roll mill so that a uniform liquid was obtained, to obtain a sealant. The pH of the light-shielding agent (D) was determined by diluting (D) the light-shielding agent 20-fold with pure water and stirring, and then measuring the pH of the pure water containing the light-shielding agent (B) using a compact pH meter B- manufactured by HORIBA. It was determined by measuring at 71X. Further, (A) the oxygen atom equivalent of the organic acid was determined from the following equation (1).
Oxygen atom equivalent (g / eq) = (molecular weight of organic acid) / (number of oxygen atoms in one molecule of organic acid) (1)

[Example 2]
A sealant was obtained in the same manner as in Example 1 except that the content was changed to the content shown in Table 1.

[Example 3]
(D) A sealant was used in the same manner as in Example 1 except that carbon (Mitsubishi Chemical Corporation: # 2600, pH 6.5, particle size: 13 nm) was used instead of carbon (MA-100R) as a light-shielding agent. I got

[Example 4]
(D) Sealing agent in the same manner as in Example 1, except that titanium black (13M, pH 8.8, particle diameter 97 nm, manufactured by Mitsubishi Materials Corporation) was used instead of carbon (MA-100R) as a light-shielding agent. I got

[Example 5]
(A) A sealant was obtained in the same manner as in Example 1, except that phenylphosphonic acid (oxygen atom equivalent: 53 g / eq) was used as the organic acid instead of trimellitic acid.

[Comparative Example 1]
A sealant was obtained in the same manner as in Example 1, except that trimellitic acid was not added, and t-butyl peroxypivalate (manufactured by Mitsubishi Chemical: Luperox 11) was added as a thermal radical generator.

[Comparative Example 2]
A sealant was obtained in the same manner as in Example 1 except that the content was changed to the content shown in Table 1 without adding trimellitic acid.

[Comparative Example 3]
Without adding a titanocene-based photopolymerization initiator and trimellitic acid, an oxime ester-based photopolymerization initiator (manufactured by BASF: IRGACURE OXE-1, 1.2-octanedione 1- [4- (phenylthio) -2- ( O-benzoyl oxime)]) was added to obtain a sealant in the same manner as in Example 1 except that the content was changed to the content shown in Table 1.

[Comparative Example 4]
(D) A sealing agent was used in the same manner as in Example 1 except that carbon (manufactured by Asahi Carbon: SB200, pH 7.5, particle size: 26 nm) was used instead of carbon (MA-100R) as a light-shielding agent. Obtained.

[Comparative Example 5]
(A) A sealant was obtained in the same manner as in Example 2, except that 2-ethylhexyl phosphate (oxygen atom equivalent: 81 g / eq) was used instead of trimellitic acid as the organic acid.

[Comparative Example 6]
(D) A sealant was prepared in the same manner as in Example 1 except that carbon (# 7350F, pH 7.0, particle size 28 nm) was used as a light shielding agent instead of carbon (MA-100R). I got

[Comparative Example 7]
(D) A sealant similar to that of Example 1 except that carbon (Mitsubishi Chemical Corporation: # 2300, pH 8.0, particle size 15 nm) was used instead of carbon (MA-100R) as a light-shielding agent. I got

[Evaluation]
The following evaluations were performed on the sealants obtained in Examples and Comparative Examples.

<Blackness>
About 10 μl of the sealing agent was collected with a spatula, and dropped on a 25 mm × 45 mm × 5 mm thick non-alkali glass. The seal pattern was a circle having a diameter of 5 mm. Then, a pair of non-alkali glass was stuck together so as to overlap, and fixed with a jig.
The test piece fixed with the jig was irradiated with ultraviolet light (wavelength 365 nm) of 500 mW / cm ² from an ultraviolet irradiation device (manufactured by Ushio Inc.) to cure the sealant. At this time, the illuminance energy of the ultraviolet light was 3.0 J / cm ² . The test piece cured by light was heated in an oven at 120 ° C. for 60 minutes to obtain a sample for measuring blackness.
The transmittance (% T) of the seal member (cured sealant) was measured using an ultraviolet-visible spectrophotometer (UV-2550, manufactured by Shimadzu Corporation). Then, using the transmittance (% T) at a wavelength of 500 nm, the blackness (OD value) was calculated by converting the density into "OD value = -log (% T / 100)".

<Dispersibility>
About 10 μl of the sealing agent was collected with a spatula, and dropped on a 25 mm × 45 mm × 5 mm thick non-alkali glass. The seal pattern was a circle having a diameter of 5 mm. Then, a pair of non-alkali glass was stuck together so as to overlap, and fixed with a jig.
The test piece fixed with the jig was irradiated with ultraviolet light (wavelength 365 nm) of 500 mW / cm ² from an ultraviolet irradiation device (manufactured by Ushio Inc.) to cure the sealant. At this time, the illuminance energy of the ultraviolet light was 3.0 J / cm ² . The test piece cured by light was heated in an oven at 120 ° C. for 60 minutes to obtain a sample for dispersibility evaluation.
This sample was observed with a microscope, and the number of foreign substances (aggregates of light-shielding agents) present in a visual field of 2 mm × 2 mm was counted.
○: No foreign matter △: Less than 10 foreign matters ×: 10 or more foreign matters

<Evaluation of photocurability (liquid crystal leak)>
Using a dispenser (Musashi Engineering Shotmaster), a 40 mm × 45 mm glass substrate (RT-DM88-PIN manufactured by EHC) on which a transparent electrode and an alignment film have been formed in advance using the sealants obtained in the examples and comparative examples. It was applied on a rectangular frame (main seal) having an outer size of 35 mm × 40 mm so that the line width after bonding was 0.7 mm (cross-sectional area: 3500 μm ² ). Further, a sealant was applied to the outer periphery in a square frame shape having an outer size of 38 mm × 43 mm so that the line width after bonding was 1.0 mm.
Next, a liquid crystal material (manufactured by MLC-7021-00 Merck Co., Ltd.) corresponding to the capacity of the panel after bonding the substrates was precisely dropped into the frame of the main seal using a dispenser. After bonding the glass substrates to be paired under reduced pressure, they were opened to the atmosphere and bonded. Thereafter, light of 1000 mJ / cm ² (light calibrated by a sensor having a wavelength of 365 nm) is irradiated in a state where the black matrix is covered with a substrate formed with a line / space of 300 μm / 100 μm so as to cover the lower half of the main seal. And further heated at 120 ° C. for 1 hour.
The liquid crystal display panel after the hardening treatment of the light shielding sealant was evaluated as follows.
：: No liquid crystal leakage occurred Δ: No liquid crystal leakage occurred, but liquid crystal was inserted into sealant ×: Liquid crystal leakage occurred

<Evaluation of photocurability (adhesive strength)>
The sealant was printed on a 25 mm × 45 mm × 5 mm thick non-alkali glass using a screen plate. The seal pattern was a circle having a diameter of 1 mm. Then, they were mounted on a pair of non-alkali glass in a seal pattern and fixed with a jig.
The test piece fixed by the jig was irradiated with an ultraviolet ray (wavelength: 365 nm) of 500 mW / cm ^{2 by} an ultraviolet ray irradiation device (manufactured by Ushio Inc.) to cure the light-shielding sealant. At this time, the illuminance energy of the ultraviolet rays was 3.0 J / cm ² . The test piece obtained by curing the light-shielding sealant with light was heated at 120 ° C. for 60 minutes using an oven to obtain a sample for measuring the adhesive strength.
Using a tensile tester (manufactured by Intesco Corporation), the tensile speed was set to 2 mm / min, and the cured light-shielding sealant was peeled off in a direction parallel to the glass bottom surface to measure the tensile strength in a plane. Here, the adhesive strength was evaluated in the following four stages according to the magnitude of the plane tensile strength.
◎: Tensile strength of 15 MPa or more 〇: Tensile strength of 10 MPa or more and less than 15 MPa ×: Tensile strength of less than 10 MPa

<Liquid crystal contamination (voltage holding ratio)>
0.1 g of the sealant obtained in each of Examples and Comparative Examples and 1 g of liquid crystal (MLC-7021-000, manufactured by Merck) were charged into a vial and heated at 120 ° C. for 1 hour to obtain a liquid crystal mixture. Obtained. Next, the liquid crystal mixture is taken out, injected into a glass cell (KSS-10 / B111M1NSS05, manufactured by EHC) on which a transparent electrode is formed in advance, a voltage of 1 V is applied, and a voltage holding ratio at 60 Hz is measured by a 6254 type measuring device. (Manufactured by Toyo Technica). The evaluation was performed as follows.
〇: When the voltage holding ratio is 90% or more (contamination to the liquid crystal is small)
×: When the voltage holding ratio was less than 90% (contamination of the liquid crystal occurred).

<Stability evaluation>
Into a syringe for dispensing, 10 g of the sealant obtained in each of Examples and Comparative Examples was placed, and defoaming treatment was performed. The initial viscosity was measured using 2 g of the sealant after the de-treatment. The sealant was stored at 23 ° C., 50% RH under a yellow room for one week, and the viscosity after storage was measured. The respective viscosities were measured using an E-type rotary viscometer (manufactured by BROOKFIELD, digital rheometer model DV-III ULTRA). Specifically, after leaving the sealant at 25 ° C. for 5 minutes, the measurement was performed at a rotation speed of 2.5 rpm using a CP-52 cone-plate sensor having a radius of 12 mm and an angle of 3 °. From the obtained values, the stability (viscosity stability) was evaluated as follows.
（(Excellent): The ratio of the viscosity after one week to the initial viscosity (increase rate) was 1.2 times or less. Δ (somewhat excellent): The ratio of the viscosity after one week to the initial viscosity (increase rate) was 1 X: less than 1.5 times × (poor): The ratio of the viscosity after one week to the initial viscosity (increase rate) exceeded 1.5 times

As shown in Table 1, when the pH of (D) the light-shielding agent was less than 7.0 or more than 8.0, the dispersibility was easily improved (Examples 1 to 5 and Comparative Examples 1 to 5). 3, 5). On the other hand, when the pH of the light-shielding agent (D) was 7.0 or more and 8.0 or less, the dispersibility was low and the liquid crystal could not be sufficiently sealed (Comparative Examples 4, 6, and 7). .

However, even if (D) the pH of the light-shielding agent is less than 7.0 or more than 8.0, if (A) the organic acid is not contained, the photocurability is low and the liquid crystal leaks easily. (Comparative Examples 1 to 3). When the oxygen atom equivalent of (A) the organic acid was more than 75 g / eq, the liquid crystal was easily contaminated (Comparative Example 5).

This application claims the priority based on Japanese Patent Application No. 2018-138353 filed on July 24, 2018. The contents described in the specification of this application are all incorporated herein by reference.

The sealant of the present invention has high photocurability and can reliably seal between substrates of a liquid crystal display panel without causing contamination of liquid crystal. Therefore, a highly reliable display panel can be manufactured, which is suitable for manufacturing various liquid crystal display panels.

Claims (10)

1. (A) an organic acid;
   (B) a photocurable resin having at least one ethylenically unsaturated double bond in one molecule (however, excluding the (A) organic acid);
   (C) a titanocene-based photopolymerization initiator;
   (D) a light-shielding agent having a pH of less than 7.0 or a pH of more than 8.0,
   (E) a thermosetting compound having at least one epoxy group in one molecule (however, excluding the (B) photocurable resin);
   (F) a thermosetting agent,
   Including
   (A) A light-shielding sealant for a liquid crystal dropping method, wherein the organic acid has an oxygen atom equivalent represented by the following formula (1) of 23 g / eq or more and 75 g / eq or less.
   Oxygen atom equivalent (g / eq) = (molecular weight of organic acid) / (number of oxygen atoms in one molecule of organic acid) (1)
2. Blackness is 2 to 5,
   The light-shielding sealant for a liquid crystal dropping method according to claim 1.
3. (D) the light-shielding agent contains at least one of carbon and titanium,
   The light-shielding sealant for a liquid crystal dropping method according to claim 1.
4. (A) In one molecule of the organic acid, an —OH group, a —NH ₂ group, a —NHR group (R represents an aromatic or an aliphatic hydrocarbon or a derivative thereof), a —COOH group, and —OP ( ＝ O) (OH) ₂ groups, —P (＝ O) (OH) ₂ groups, —SO ₃ H groups, —CONH ₂ groups, and —NHOH groups, having at least one functional group.
   The light-shielding sealant for a liquid crystal dropping method according to any one of claims 1 to 3.
5. (B) the photocurable resin further has an epoxy group in the molecule,
   The light-shielding sealant for a liquid crystal dropping method according to any one of claims 1 to 4.
6. (F) at least one selected from the group consisting of a dihydrazide heat latent curing agent, an imidazole heat latent curing agent, an amine adduct heat latent curing agent, and a polyamine heat latent curing agent. Is,
   The light-blocking sealant for a liquid crystal dropping method according to any one of claims 1 to 5.
7. A step of forming a seal pattern on one of the substrates using the light-shielding sealant for a liquid crystal dropping method according to any one of claims 1 to 6,
   In the uncured state of the seal pattern, in the region of the seal pattern, or a step of dropping liquid crystal on the other substrate paired with the one substrate,
   Superimposing the one substrate and the other substrate via the seal pattern,
   Curing the seal pattern,
   A method for manufacturing a liquid crystal display panel, comprising:
8. Curing the seal pattern includes irradiating the seal pattern with light to cure the seal pattern.
   A method for manufacturing a liquid crystal display panel according to claim 7.
9. The light applied to the seal pattern includes light in a visible light region,
   A method for manufacturing a liquid crystal display panel according to claim 8.
10. The step of curing the seal pattern further includes a step of heating and curing the seal pattern irradiated with light,
    A method for manufacturing a liquid crystal display panel according to claim 8.