WO2011001895A1 - Liquid crystal sealing agent for liquid crystal dropping method and liquid crystal display cell using same - Google Patents

Abstract

Disclosed is a thermosetting liquid crystal sealing agent for a liquid crystal dropping method, which contains, as essential components, (a) a curable resin that is composed of an epoxy resin and a (meth)acrylated epoxy resin, (b) a polyfunctional hydrazide compound, (c) a curing accelerator, (d) an inorganic filler and (e) a silicone rubber powder that has a true specific gravity of 0.95-1.0 and an average particle diameter of 10-18 μm. The thermosetting liquid crystal sealing agent for a liquid crystal dropping method contains the silicone rubber powder (e) in an amount of 5-40% by mass relative to the liquid crystal sealing agent.

Description

Liquid crystal sealing agent for liquid crystal dropping method and liquid crystal display cell using the same

The present invention relates to a liquid crystal sealant and a liquid crystal display cell using the same. More specifically, the present invention relates to a liquid crystal sealant suitable for manufacturing a liquid crystal display cell by a liquid crystal dropping method and a liquid crystal display cell manufactured using the same.

Along with the increase in the size of liquid crystal display cells, in recent years, the liquid crystal display cell manufacturing method has been introduced by introducing a liquid crystal dropping method with higher mass productivity from the conventional liquid crystal display method using the liquid crystal vacuum injection method. (See Patent Document 1). Specifically, the liquid crystal dropping method is to apply a liquid crystal sealing agent weir on the liquid crystal substrate (main seal), and then apply the sealing agent to the outermost circumference, apply the sealing agent (dummy seal), and then place the liquid crystal inside the inner seal. After that, the other liquid crystal substrate facing each other in a vacuum is bonded together, and the liquid crystal is sealed by releasing to atmospheric pressure, and the liquid crystal display cell is completed by curing the seal portion by UV irradiation and heating. This is a manufacturing method. As a liquid crystal sealing material used for sealing liquid crystal in this manufacturing method, not a conventional thermosetting liquid crystal sealing agent but a photothermosetting combined type liquid crystal sealing agent is generally used. The reason why the conventional thermosetting liquid crystal sealant is not used in the liquid crystal dropping method is that when the liquid crystal dropping method is used with the conventional thermosetting liquid crystal sealing agent, the thermal expansion of the liquid crystal during heating and the viscosity decrease due to the heating of the liquid crystal sealing agent This is because the seal is punctured and the liquid crystal cannot be sealed due to the vacuum pressure reduction.

The photo-curing combined type liquid crystal sealant is used by applying a liquid crystal sealant weir to the liquid crystal substrate with a dispenser, etc., then dropping the liquid crystal inside the weir and attaching the other substrate facing in vacuum. After the alignment, the liquid crystal cell is manufactured by irradiating the seal portion with light such as ultraviolet rays and temporarily curing, and then thermally curing the liquid crystal sealant at about 120 ° C. for about 1 hour.

However, in the case of the photothermographic combination type, the liquid crystal sealant must be irradiated with light such as ultraviolet rays, but the liquid crystal seal part is shielded by wiring or black matrix with the narrowing of the frame of the liquid crystal cell in recent years. The liquid crystal sealant has a portion that is not irradiated with light, and an uncured portion due to light shielding of the liquid crystal seal is inserted into the liquid crystal during the heat curing process, or liquid crystal contamination occurs. In designing the liquid crystal cell, there has been a restriction that the sealant must be designed so that as much light as possible is irradiated. Further, since deterioration of the liquid crystal and alignment film due to ultraviolet irradiation becomes a problem, it takes time and effort to shield the liquid crystal portion with a light shielding mask during the ultraviolet irradiation process so that the ultraviolet rays do not hit the liquid crystal. Furthermore, with the increase in the size of the liquid crystal glass substrate, there are problems such as an increase in the size of the ultraviolet irradiation device and an increase in the running cost of the ultraviolet irradiation device.

In view of the above, in recent years, it has been desired to realize a thermosetting liquid crystal sealing agent for a liquid crystal dropping method capable of producing a liquid crystal display cell only by thermosetting which does not require ultraviolet irradiation.

To date, proposals have been made for thermosetting liquid crystal sealing agents for liquid crystal dropping methods. For example, in Patent Document 2, 3 to 40 thermosetting agents are added to 100 parts by weight of a curable resin having a value obtained by dividing the number of hydrogen bonding functional groups in one molecule by molecular weight of 3.5 × 10 ⁻⁴ or more. A thermosetting liquid crystal sealing agent for liquid crystal dropping method containing parts by weight has been proposed. It has been proposed that this liquid crystal sealant causes low liquid crystal contamination. However, in the thermosetting type liquid crystal dropping method, the thermal expansion of the liquid crystal due to heating and the reduced-pressure sealing in vacuum cause the liquid crystal to leak because the weir of the liquid crystal sealant that has been reduced in viscosity by heating is broken. And the liquid crystal sealant component, which has been reduced in viscosity by heating, elutes and contaminates liquid crystals that are more likely to flow by being heated to the NI point or higher. Although there are serious problems, a method for solving these problems is not disclosed in Patent Document 2.

Further, Patent Document 3 proposes that a liquid crystal sealant to which a gelling agent is added can prevent seal puncture and keep the seal shape by a liquid crystal dropping method only by thermosetting. However, Patent Document 3 does not clearly indicate the contamination of the liquid crystal sealant during heating and curing, which is a problem of the thermosetting liquid crystal dropping method.

Patent Document 4 proposes a manufacturing method in which a liquid crystal sealant made of a thermosetting resin is applied, prebaked, and then subjected to liquid crystal dropping and vacuum bonding. However, the resin composition of the liquid crystal sealant is clearly shown. Has not been.

Patent Documents 5 and 6 propose a thermosetting liquid crystal dropping method liquid crystal dropping method that performs a pre-baking process as a B-stage process, but requires a B-stage process at 80 ° C. for 20 minutes. Therefore, there is a drawback that the process time becomes long. In order to shorten the B stage treatment time for 20 minutes, the treatment temperature may be increased to, for example, 100 ° C. or higher. However, the liquid crystal sealant described in the above-mentioned patent document has a main curing reaction at 100 ° C. or higher. Therefore, it is not preferable. As described above, it is difficult to develop a thermosetting liquid crystal dropping sealant that solves all of these problems, and a thermosetting liquid crystal dropping method has not yet been realized.

In addition, in recent years, there has been a strong demand for a larger display area without increasing the outer size of the substrate, and the liquid crystal cell such as a narrower frame that narrows the outer periphery of the liquid crystal seal and a narrower liquid crystal seal width are used. Designs are being made. Therefore, there has been a demand for a liquid crystal sealant that can be formed with a narrow seal width and has a uniform seal shape that is not easily disturbed, or a liquid crystal sealant that has high adhesive strength even if the seal width is small. Further, there is a demand for a liquid crystal sealant having a long pot life in which the change in the application condition of the liquid crystal sealant is small within the working time.

In recent years, with the spread of liquid crystal televisions and the like, the cell gap of the liquid crystal (the gap between the two substrates filled with liquid crystal) is narrowed in order to increase the high-speed response of the liquid crystal when playing back moving images. It is coming. For this reason, a liquid crystal sealant that can easily narrow the cell gap when the liquid crystal substrate is vacuum-bonded has been demanded.

And in response to the demand for a long life of the liquid crystal cell, deterioration of the liquid crystal seal under high humidity conditions has become a problem. For this reason, a liquid crystal sealant having a small deterioration of the adhesive strength of the liquid crystal seal after the high temperature and high humidity test has been demanded.

As described above, a thermosetting liquid crystal dropping method is realized, seal puncture is not caused by vacuum heating, there is no liquid crystal contamination, adhesive strength and adhesive strength after a moisture resistance test are strong, excellent seal applicability, and room temperature Therefore, there is a demand for a liquid crystal sealant for a thermosetting liquid crystal dropping method that has a long pot life and can easily narrow the cell gap.

Japanese Patent Publication No. 8-20627 Japanese Patent No. 3955038 Japanese Patent No. 3976749 JP 2005-92043 A JP 2007-199710 A JP 2007-224117 A

The present invention is to provide a thermosetting liquid crystal sealing agent for a liquid crystal dropping method that does not require ultraviolet irradiation on the liquid crystal sealing portion. In addition, liquid crystal seals for thermosetting liquid crystal dripping method with low liquid-contamination property, strong adhesive strength and high adhesive strength after moisture resistance test, excellent seal linearity, long pot life at room temperature, and easy narrowing of cell gap It is to provide an agent.

The present inventors have completed the present invention as a result of intensive studies to solve the above-mentioned problems. That is, the present invention relates to the following (1) to (8).

(1) Epoxy resin and (meth) acrylated epoxy resin curable resin (a), polyfunctional hydrazide compound (b), curing accelerator (c), inorganic filler (d), and true specific gravity of 0. Silicone rubber powder (e) having an average particle diameter of 95 to 1.0 and an average particle diameter of 10 to 18 μm is contained as an essential component, and the content of the silicone rubber powder (e) is 5 to 40% by mass in the liquid crystal sealant. A liquid crystal sealant for a certain thermosetting liquid crystal dropping method.

(2) The liquid crystal sealing agent for thermosetting liquid crystal dropping method according to (1), wherein the silicone rubber powder (e) is a fine powder of an addition polymer of vinyl group-containing organopolysiloxane and organohydrogenpolysiloxane.

(3) The thermosetting liquid crystal dropping method according to (1) or (2), wherein the polyfunctional hydrazide compound (b) is a polyfunctional hydrazide compound having an isocyanuric ring skeleton represented by the following general formula (1): Liquid crystal sealant.

（式（１）中、Ｒ^１～Ｒ^３は各々独立して水素原子又は下記式（２）で表される分子骨格であり、Ｒ^１～Ｒ^３のうち少なくともいずれか２つは式（２）で表される基を示す。）

(In Formula (1), R ¹ to R ³ are each independently a hydrogen atom or a molecular skeleton represented by Formula (2) below, and at least any two of R ¹ to R ³ are represented by Formula (2) ) Represents a group represented by

（式（２）中、ｎは１～６の整数を示す。）

(In formula (2), n represents an integer of 1 to 6)

(4) The liquid crystal sealing agent for thermosetting liquid crystal dropping method according to any one of (1) to (3), wherein the inorganic filler (d) is at least one of alumina and silica.

(5) The thermosetting liquid crystal according to any one of (1) to (4), wherein the curing accelerator (c) is a polyvalent carboxylic acid compound having an isocyanuric ring skeleton represented by the following general formula (3). Liquid crystal sealant for dripping method.

（式（３）中、Ｔ^１～Ｔ^３は各々独立して水素原子又は下記式（４）で表される分子骨格であり、Ｔ^１～Ｔ^３のうち少なくともいずれか２つは式（４）で表される基を示す。）

(In formula (3), T ¹ to T ³ are each independently a hydrogen atom or a molecular skeleton represented by the following formula (4), and at least any two of T ¹ to T ³ are represented by formula (4 ) Represents a group represented by

（式（４）中、ｎは１～６の整数を示す。）

(In formula (4), n represents an integer of 1 to 6)

(6) The liquid crystal sealing agent for thermosetting liquid crystal dropping method according to any one of (1) to (5), which contains a polythiol compound.

(7) The liquid crystal sealant for a thermosetting liquid crystal dropping method according to any one of (1) to (6), which contains a coupling agent.

(8) A liquid crystal display cell sealed with a cured product of the liquid crystal sealing agent according to any one of (1) to (7).

The liquid crystal sealant of the present invention enables a thermosetting type liquid crystal dropping method that does not require UV irradiation to the liquid crystal seal part, and further has low liquid crystal contamination and high adhesion strength and adhesion strength after a moisture resistance test. With excellent seal linearity, long pot life at room temperature, and easy manufacture of narrow cell gap liquid crystal cells, high-reliability and high-quality liquid crystal display cell manufacture can be produced with high yield. became.

Hereinafter, the present invention will be described in detail. The liquid crystal sealant for the thermosetting liquid crystal dropping method of the present invention (hereinafter also simply referred to as “liquid crystal sealant”) includes a curable resin (a), a polyfunctional hydrazide compound (b), a curing accelerator (c), an inorganic material. The silicone rubber powder (e) having a filler (d) and a true specific gravity of 0.95 to 1.0 and an average particle diameter of 10 to 18 μm are contained as essential components, and the content of the silicone rubber powder (e) is It is 5 to 40% by mass in the liquid crystal sealant.

In the liquid crystal sealant of the present invention, an epoxy resin and a (meth) acrylated epoxy resin are used as the curable resin (a). (Here, “(meth) acryl” means at least one of “acryl” and “methacryl”.) The curable resin (a) used in the present invention has both contamination and solubility in liquid crystals. Those having a low resin viscosity are preferred.

Examples of suitable epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, ethylene oxide-added bisphenol S type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, and bisphenol A. Novolac type epoxy resin, bisphenol F novolac type epoxy resin, resorcin diglycidyl ether, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type Epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy having triphenolmethane skeleton Fat, other, diglycidyl ethers of bifunctional phenols, bifunctional alcohols diglycidyl ethers of and the like. Epoxy resins may be used alone or in combination of two or more. Of these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, ethylene oxide-added bisphenol S type epoxy resin, and resorcin diglycidyl ether are more preferable from the viewpoint of liquid crystal contamination and viscosity. Particularly preferred.

(Meth) acrylated epoxy resin is obtained by reaction of epoxy resin and (meth) acrylic acid, and all epoxy groups of epoxy resin are (meth) acrylated epoxy resins, epoxy groups of epoxy resin, etc. Also included is a partially (meth) acrylated epoxy resin in which less than the amount of (meth) acrylic acid component is reacted to intentionally leave an epoxy group. The (meth) acrylated epoxy resin is preferably a compound having a bifunctional or higher (meth) acryloyl group. Further, a structure having both a (meth) acryloyl group and an epoxy group in one molecule may be used. In this case, the ratio of the epoxy group to the (meth) acryloyl group is not limited and is appropriately selected from the viewpoint of process compatibility and liquid crystal contamination. The (meth) acrylated epoxy resin may be used alone or in combination of two or more.

The epoxy resin used as a raw material for the (meth) acrylated epoxy resin is not particularly limited, but is preferably a bifunctional or higher epoxy resin, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type. Epoxy resin, ethylene oxide-added bisphenol S epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin, bisphenol F novolac epoxy resin, resorcin diglycidyl ether, alicyclic epoxy resin, fat Chain epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, dicyclopentadiene Epoxy resins, biphenyl type epoxy resins, phenol novolac type epoxy resins having a triphenolmethane skeleton, other diglycidyl ethers of bifunctional phenols, diglycidyl ethers of bifunctional alcohols, etc. are preferable, but bisphenol is preferred. A type epoxy resin, bisphenol F type epoxy resin, and resorcin diglycidyl ether, among which resorcin diglycidyl ether is more preferable. The (meth) acrylated epoxy resin is preferably an acrylated epoxy resin obtained by a reaction between an epoxy resin and acrylic acid from the viewpoint of curability. More preferred are acrylic acid adducts of bisphenol F type epoxy resins and acrylic acid adducts of resorcin diglycidyl ether.

The content of the epoxy resin and the curable resin (a) which is a (meth) acrylated epoxy resin in the liquid crystal sealing agent is usually 30 to 70% by mass, preferably 40 to 60% by mass. When the content is less than 30% by mass, the reaction at the time of thermosetting is delayed, and the seal weir is sealed puncture due to the thermal expansion of the liquid crystal and the lowering of the viscosity of the sealing resin when the liquid crystal cell is manufactured by the liquid crystal dropping method. When the content is more than 70% by mass, sufficient adhesive strength cannot be obtained. The content of the epoxy resin in the curable resin (a) is usually 3 to 30% by mass, preferably 5 to 20% by mass, and more preferably 8 to 15% by mass. When the epoxy resin content is less than 3% by mass, the adhesive strength is weakened, and when the epoxy resin content is more than 30% by mass, the curing becomes slow and seal puncture tends to occur.

The liquid crystal sealant of the present invention contains a polyfunctional hydrazide compound (b). In this case, the polyfunctional hydrazide compound (b) refers to a compound having two or more hydrazide groups in the molecule. Specific examples thereof include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, and adipic acid. Dihydrazide, Pimelic acid dihydrazide, Suberic acid dihydrazide, Azelaic acid dihydrazide, Sebacic acid dihydrazide, Dodecanediodihydrazide, Hexadecanediohydrazide, Maleic acid dihydrazide, Fumaric acid dihydrazide, Diglycolic acid dihydrazide, Tartaric acid dihydrazide dihydrazide Terephthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4-bisbenzenedihydrazide, 1,4-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,2 Hydrazides having a valine hydrantin skeleton such as 4-benzenetrihydrazide, pyromellitic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydrazide, 1,3-bis (hydrazinocarbonoethyl) -5-isopropylhydantoin Compounds, and further tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazinocarbonylpropyl) isocyanurate represented by the general formula (1) Bis (2-hydrazinocarbonylethyl) isocyanurate, and the like may be used alone or in combination of two or more. Of these polyfunctional hydrazide compounds, preferred are adipic acid dihydrazide, isophthalic acid dihydrazide, 1,3-bis (hydrazinocarbonoethyl) -5-isopropylhydantoin, and tris (1-hydrazinocarbonylmethyl) isocyanurate. , Tris (2-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazinocarbonylpropyl) isocyanurate, and bis (2-hydrazinocarbonylethyl) isocyanurate, more preferably represented by the general formula (1). Tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazinocarbonylpropyl) isocyanurate, bis (2-hydrazinocarbonylethyl) Polyfunctional hydrazide compound include having an isocyanuric ring skeleton such as isocyanurate, more preferably, tris (2-hydrazinocarbonyl-ethyl) isocyanurate.

In order to make the polyfunctional hydrazide compound (b) a latent curing agent for rapid curing, it is preferable to finely disperse the particle size and uniformly disperse. The average particle size is preferably 3 μm or less, and more preferably 2 μm or less, because if the average particle size is too large, it becomes a cause of defects such as inability to form a gap when the upper and lower glass substrates are bonded together when manufacturing a narrow gap liquid crystal cell. The particle size of the curing agent was measured with a laser diffraction / scattering type particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd .: LMS-30). In addition, since it will become easy to raise | generate aggregation if an average particle diameter is too small, it is preferable to prepare so that it may not become extremely small (for example, 0.1 micrometer or less).

The compounding ratio of the polyfunctional hydrazide compound (b) in the liquid crystal sealant of the present invention is 5 to 70 masses with respect to 100 mass parts in total of the curable resin (a) which is an epoxy resin and a (meth) acrylated epoxy resin. About a part. When the amount of the component (b) is less than 5 parts by mass, the thermosetting reaction becomes insufficient, and the adhesive force and the glass transition point are lowered. On the other hand, when the amount of the component (b) is more than 70 parts by mass, the curing agent remains, the adhesive strength is lowered, and the pot life is also deteriorated.

The liquid crystal sealant of the present invention contains a curing accelerator (c) in order to promote the curability of the thermosetting reaction. The curing accelerator (c) is not limited as long as it has a high thermosetting reaction accelerating property during heating, low contamination to liquid crystals, and does not deteriorate the pot life of the liquid crystal sealant during normal temperature storage. And polyvalent carboxylic acid having an isocyanuric ring skeleton represented by the general formula (3), an epoxy resin amine adduct, and the like. These may be used alone or in combination of two or more. Among these curing accelerators, preferred are tris (1-carboxymethyl) isocyanurate, tris (2-carboxyethyl) isocyanurate, tris (3-carboxypropyl) isocyanurate represented by the general formula (3), Bis (2-carboxyethyl) isocyanurate can be mentioned, and tris (3-carboxypropyl) isocyanurate is more preferable.

In order to make the curing accelerator (c) a latent curing accelerator for immediate curing, it is preferable that the particle size is finely dispersed uniformly. The average particle size is preferably 3 μm or less, and more preferably 2 μm or less, because if the average particle size is too large, it becomes a cause of defects such as inability to form a gap when the upper and lower glass substrates are bonded together when manufacturing a narrow gap liquid crystal cell. Moreover, since the room temperature storage stability will worsen if too small, the minimum of the average particle diameter of a hardening accelerator is about 1 micrometer normally.

In the present invention, the content of the curing accelerator (c) in the liquid crystal sealant is preferably 0.1 to 10% by mass, more preferably 0.3 to 8% by mass. When the content is less than 0.1% by mass, the curability is deteriorated and seal puncture occurs, and when the content is more than 10% by mass, the room temperature storage stability is deteriorated.

Examples of the inorganic filler (d) used in the present invention include alumina, silica, talc, clay, bentonite, organic bentonite, barium titanate, titanium oxide, cobalt oxide, magnesium oxide, nickel oxide, and zirconium oxide. Products, carbonates such as calcium carbonate and magnesium carbonate, sulfates such as barium sulfate and calcium sulfate, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, silica such as calcium silicate, aluminum silicate and zirconium silicate An acid salt etc. are mentioned, It may be used independently or may be used in mixture of 2 or more types. Of these inorganic fillers, particularly preferred is at least one of alumina and silica.

The average particle diameter of the inorganic filler (d) used in the present invention is preferably 3 μm or less. If the average particle size is larger than 3 μm, it will hinder the gap formation when the upper and lower glass substrates are bonded together during the production of the liquid crystal cell. The lower limit of the average particle size of the inorganic filler is usually about 0.01 μm. The content of the inorganic filler used in the present invention in the liquid crystal sealant is usually 1 to 40% by mass, preferably 2 to 30% by mass. When the content of the inorganic filler is less than 1% by mass, the adhesion strength to the glass substrate is lowered, and the moisture resistance reliability is inferior. Moreover, when there is more content of an inorganic filler than 40 mass%, since there is too much filler content, a seal | sticker cannot be crushed and it may become impossible to form the gap of a liquid crystal cell.

The silicone rubber powder (e) used in the present invention refers to a rubbery silicone resin obtained by crosslinking polysiloxane, such as a fine powder of an addition polymer of vinyl group-containing organopolysiloxane and organohydrogenpolysiloxane. Can be mentioned. These may be used alone or in combination of two or more. Among these silicone rubber powders, preferred are fine powders of addition polymers of vinyl group-containing dimethylpolysiloxane and methylhydrogenpolysiloxane. Specific examples thereof include KMP598 and X-52-875 (manufactured by Shin-Etsu Chemical Co., Ltd.).

The true specific gravity of the silicone rubber powder (e) used in the present invention is preferably 0.95 to 1.0. If the true specific gravity is greater than 1.0, the rubber particles become hard, which may hinder the formation of a gap when the upper and lower glass substrates are bonded together during liquid crystal cell manufacture. If the true specific gravity is less than 0.95, liquid crystal seal puncture may easily occur during cell fabrication. The true specific gravity can be measured by an immersion method (Archimedes method) using isopropyl alcohol. The average particle size of the silicone rubber powder (e) is preferably 10 to 18 μm. More preferably, it is 10 to 15 μm. When the average particle diameter is larger than 18 μm, the seal is difficult to be crushed. When the average particle size is smaller than 10 μm, liquid crystal seal puncture is likely to occur particularly when a cell requiring a cell gap of 5 μm or more is produced.

When the average particle diameter is in the above range, a gap can be secured at any cell gap of 1 to 8 μm, and a cell can be produced without causing seal puncture. The average particle diameter of the silicone rubber powder can be determined from a photograph taken with an electron microscope.

In the present invention, the content of the silicone rubber powder (e) in the liquid crystal sealant is 5 to 40% by mass, preferably 10 to 35% by mass. When the content is less than 5% by mass, a seal puncture occurs due to a decrease in the viscosity of the liquid crystal sealant during heating during liquid crystal cell production, and the liquid crystal leaks. When the content is more than 40% by mass, the viscosity of the liquid crystal sealant becomes too high to be applied.

Fumed silica may be added to the liquid crystal sealant of the present invention. By adding fumed silica, the thixotropy of the resin composition is increased, and the applicability, workability, and seal puncture properties of the liquid crystal sealant can be appropriately adjusted. Examples of the fumed silica used in the present invention include anhydrous amorphous silica fine particles obtained by hydrolyzing silicon tetrachloride as a raw material at a high temperature. Moreover, you may add the hydrophobic fumed silica which surface-treated fumed silica with hexamethyldisilazane, methylchlorosilanes, silicone oils, etc. When at least one of the above-described fumed silica and hydrophobic fumed silica is added to the liquid crystal sealant of the present invention, the average primary particle diameter is preferably 0.07 μm or less. The content of fumed silica (including the above-described hydrophobic fumed silica) in the liquid crystal sealant is preferably about 0.5 to 10% by mass.

The liquid crystal sealant of the present invention may contain a polythiol compound in order to improve curability. The polythiol compound in this case refers to a compound having two or more thiol groups in the molecule, and specific examples thereof include, for example, methanedithiol, 1,2-dimercaptoethane, 1,2-dimercaptopropane, 2,2-dimercaptopropane, 1,3-dimercaptopropane, 1,2,3-trimercaptopropane, 1,4-dimercaptobutane, 1,6-dimercaptohexane, bis (2-mercaptoethyl) sulfide 1,2-bis (2-mercaptoethylthio) ethane, 1,5-dimercapto-3-oxapentane, 1,8-dimercapto-3,6-dioxaoctane, 2,2-dimethylpropane-1,3 -Dithiol, 3,4-dimethoxybutane-1,2-dithiol, 2-mercaptomethyl-1,3-dimercaptopropane, 2- Lucaptomethyl-1,4-dimercaptobutane, 2- (2-mercaptoethylthio) -1,3-dimercaptopropane, 1,2-bis (2-mercaptoethylthio) -3-mercaptopropane, 1,1, 1-tris (mercaptomethyl) propane, tetrakis (mercaptomethyl) methane, ethylene glycol bis (2-mercaptoacetate), ethylene glycol bis (3-mercaptopropionate), 1,4-butanediol bis (2-mercaptoacetate) ), 1,4-butanediol bis (3-mercaptopropionate), trimethylolpropane tris (2-mercaptoacetate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptocete) Tate) Taerythritol tetrakis (3-mercaptopropionate), 1,1-dimercaptocyclohexane, 1,4-dimercaptocyclohexane, 1,3-dimercaptocyclohexane, 1,2-dimercaptocyclohexane, dipentaerythritol hexakis ( 3-mercaptopropionate), dipentaerythritol hexakis (2-mercaptoacetate), 1,2-dimercaptobenzene, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1, 2-dimercapto-1,3-butanediol, hydroxymethyl-tris (mercaptoethylthiomethyl) methane, hydroxyethylthiomethyl-tris (mercaptoethylthio) methane, ethylene glycol bis (3-mercaptopropionate) ), Propylene glycol bis (3-mercaptopropionate), butanediol bis (3-mercaptopropionate), octanediol bis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate) ), Ethylene glycol bis (4-mercaptobutyrate), propylene glycol bis (4-mercaptobutyrate), butanediol bis (4-mercaptobutyrate), octanediol bis (4-mercaptobutyrate), trimethylolpropane tris (4-mercaptobutyrate), pentaerythritol tetrakis (4-mercaptobutyrate), ethylene glycol bis (6-mercaptovalerate), propylene glycol bis (6-mercaptovalerate), butane Allbis (6-mercaptovalerate), octanediol bis (6-mercaptovalerate), trimethylolpropane tris (6-mercaptovalerate), pentaerythritol tetrakis (6-mercaptovalerate), 1,6-hexanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 4,4′-bis (mercaptomethyl) phenyl sulfide, 2,4′-bis (mercaptomethyl) phenyl sulfide, 2,4,4′-tri (mercapto) Methyl) phenyl sulfide, 2,2 ′, 4,4′-tetra (mercaptomethyl) phenyl sulfide, 1,3,5-tris [2- (3-mercaptopropionyloxy) ethyl] -1,3,5-triazine -2,4,6 (1H, 3H, 5H) -trione, 1,3 5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate), 1,4- Examples thereof include bis (3-mercaptobutyryloxy) butane, and these may be used alone or in combination of two or more. Among these polythiol compounds, preferred are trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate), 1,3,5-tris [2- (3-mercaptopropionyloxy) ethyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris (3-Mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate) are preferable, and liquid crystal is more preferable. 1,3,5-trimethyl having a secondary thiol structure from the viewpoint of contamination and room temperature storage stability (3-mercaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (IH, 3H, 5H) - trione, pentaerythritol tetrakis (3-mercapto butyrate) is particularly preferred. The content of the polythiol compound in the liquid crystal sealant is usually 0.1 to 20% by mass, preferably 0.3 to 10% by mass, and more preferably 0.5 to 10% by mass. When the content is less than 0.1% by mass, the curability is deteriorated and seal puncture occurs, and when the content is more than 20% by mass, the room temperature storage stability is deteriorated.

In the liquid crystal sealant of the present invention, a coupling agent may be added in order to improve the adhesive strength. Although there is no special limitation in the coupling agent to be used, it is preferable to contain a silane coupling agent. Examples of silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri Methoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, 3-amino Propyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3 -Black Silane coupling agents such as propylmethyldimethoxysilane and 3-chloropropyltrimethoxysilane, isopropyl (N-ethylaminoethylamino) titanate, isopropyl triisostearoyl titanate, titanium di (dioctyl pyrophosphate) oxyacetate, tetraisopropyl di Titanium coupling agents such as (dioctyl phosphite) titanate and neoalkoxytri (pN- (β-aminoethyl) aminophenyl) titanate, Zr-acetylacetonate, Zr-methacrylate, Zr-propionate, neoalkoxyzirco , Neoalkoxytris neodecanoyl zirconate, neoalkoxytris (dodecanoyl) benzenesulfonyl zirconate, neoalkoxytris (ethyl) (Diaminoethyl) zirconate, neoalkoxy tris (m-aminophenyl) zirconate, zirconium such as ammonium zirconium carbonate, Al-acetylacetonate, Al-methacrylate, Al-propionate, or aluminum coupling agents. It may be used in a mixture of two or more. A silane coupling agent is preferable, and an aminosilane coupling agent or an epoxysilane coupling agent is more preferable. By using a coupling agent, a liquid crystal sealant having excellent moisture resistance reliability and little decrease in adhesive strength after moisture absorption can be obtained. The content of the coupling agent in the liquid crystal sealing agent is about 0.05 to 3% by mass.

An organic filler may be added to the liquid crystal sealant of the present invention as long as it does not affect the properties of the liquid crystal sealant. Examples of the organic filler include polymer beads and core-shell type acrylic rubber fillers. These fillers may be used alone or in combination of two or more.

The average particle size of the organic filler added is 5 μm or less, preferably 2 μm or less. When the average particle size is larger than 5 μm, it becomes difficult to form a cell gap. Moreover, the addition amount of the organic filler which can be added is preferably 30% by mass or less of the mass of the inorganic filler (d). When the amount is more than 30% by mass, the viscosity becomes high and it becomes difficult to form a cell gap.

In the liquid crystal sealant according to the present invention, additives such as a photo radical polymerization initiator, a thermal radical generator, an organic solvent, a pigment, a leveling agent, and an antifoaming agent can be further blended as necessary.

The liquid crystal sealant of the present invention includes, for example, a curable resin (a) that is an epoxy resin and a (meth) acrylated epoxy resin, and a polyfunctional hydrazide compound in which a coupling agent or additive is dissolved and mixed as necessary. (B), curing accelerator (c), inorganic filler (d), silicone rubber powder (e) and other optional components such as fumed silica are added as appropriate, and a known mixing device such as a three-roll, sand mill It can be produced by uniformly mixing with a ball mill or the like. After mixing is completed, it is preferable to perform a filtration treatment to remove foreign substances.

In the liquid crystal display cell of the present invention, a pair of substrates on which predetermined electrodes are formed are arranged opposite to each other at a predetermined interval, the periphery is sealed with the liquid crystal sealant of the present invention, and the liquid crystal is sealed in the gap. That is, it is sealed with a cured product of a liquid crystal sealant. The kind of liquid crystal to be sealed is not particularly limited. Here, the substrate is composed of a substrate made of glass, quartz, plastic, silicon or the like.

In the manufacturing method of the liquid crystal display cell by the thermosetting liquid crystal dropping method, first, a spacer (gap control material) such as glass fiber is added to and mixed with the liquid crystal sealing agent of the present invention. Examples of the spacer include glass fiber, silica beads, and polymer beads. The diameter varies depending on the purpose, but is usually 2 to 8 μm, preferably 3 to 6 μm. The amount used is usually about 0.1 to 4 parts by weight, preferably about 0.5 to 2 parts by weight, more preferably about 0.9 to 1.5 parts by weight with respect to 100 parts by weight of the liquid crystal sealant of the present invention. . After applying a liquid crystal sealant containing a spacer to one side of the substrate with a dispenser or the like to form a weir (main seal), in order to keep the liquid crystal sealing substrate in a vacuum, the sealant is further applied to the outermost circumference. Apply (dummy seal). Thereafter, the liquid crystal is dropped inside the weir of the internal seal, and the other glass substrate is overlaid in a vacuum, and then opened to the atmospheric pressure to release the gap. The dummy sealant for holding the liquid crystal sealing substrate in a vacuum does not come into contact with the liquid crystal and is cut off after completion of the liquid crystal cell. Even if the same liquid crystal sealant is used, another UV curable type is used. A sealant, a visible light curable sealant, or a thermosetting sealant may be used. When a UV curable sealant or a visible light curable sealant is used for the dummy seal after the vacuum gap is formed, the dummy seal part is irradiated with ultraviolet rays or visible light by an ultraviolet irradiator or a visible light irradiator. Light cure. If no photo-curing sealant is used for the dummy seal, the light irradiation step is omitted. The liquid crystal display cell of the present invention can be obtained by heating the gap-formed substrate at 90 to 130 ° C. for 1 to 2 hours. The liquid crystal display cell of the present invention thus obtained has no display defects due to liquid crystal contamination, and has excellent adhesion and moisture resistance reliability.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited at all by the following examples.

Synthesis Example 1 [Synthesis of Resorcined Diglycidyl Ether Total Acrylate]:
Resorcin diglycidyl ether resin was dissolved in toluene, dibutylhydroxytoluene was added thereto as a polymerization inhibitor, and the temperature was raised to 60 ° C. Thereafter, acrylic acid with 100% equivalent of epoxy group was added, the temperature was further raised to 80 ° C., trimethyl ammonium chloride as a reaction catalyst was added thereto, and the mixture was stirred at 98 ° C. for about 50 hours. The obtained reaction liquid was washed with water, and toluene was distilled off to obtain an epoxy acrylate of resorcin.

Examples 1 and 2, Comparative Examples 1 to 3:
An acrylated epoxy resin, an epoxy resin, and a silane coupling agent described in Table 1 were mixed to obtain a resin liquid. Next, in Example 1, an inorganic filler, a polyfunctional hydrazide compound, a curing accelerator, silicone rubber powder, and a polythiol compound were mixed to obtain a liquid crystal sealant. In Example 2, an inorganic filler, a polyfunctional hydrazide compound, a curing accelerator, and silicone rubber powder were mixed to obtain a liquid crystal sealant. In Comparative Example 1, an inorganic filler, a polyfunctional hydrazide compound, a curing accelerator, silicone rubber powder, and a polythiol compound were mixed to obtain a liquid crystal sealant. In Comparative Example 2, an inorganic filler, a polyfunctional hydrazide compound, silicone rubber powder, and a polythiol compound were mixed to obtain a liquid crystal sealant. In Comparative Example 3, an inorganic filler, a polyfunctional hydrazide compound, and a curing accelerator were mixed to obtain a liquid crystal sealant.

The numerical values in Table 1 are parts by mass. Moreover, each component in Table 1 is shown below.
* 1: Total acrylate of resorcin diglycidyl ether (Nippon Kayaku Co., Ltd .: Synthesis Example 1).
* 2: Resorcin diglycidyl ether (manufactured by Nippon Kayaku Co., Ltd .: RGE-HH).
* 3: Tris (2-hydrazinocarbonylethyl) isocyanurate (HCIC) finely pulverized product (manufactured by Nippon Finechem Co., Ltd .: finely pulverized with a jet mill to an average particle size of 1.5 μm).
* 4: Tris (3-carboxypropyl) isocyanurate (C3-CIC acid) pulverized product (manufactured by Shikoku Kasei Kogyo Co., Ltd .: finely pulverized to a mean particle size of 1.5 μm with a jet mill).
* 5: Spherical silica (manufactured by Shin-Etsu Chemical Co., Ltd .: X-24-9163A; primary average particle size 110 nm).
* 6: Silicone rubber powder A (fine powder of addition polymer of vinyl group-containing dimethylpolysiloxane and methylhydrogenpolysiloxane, manufactured by Shin-Etsu Chemical Co., Ltd .: KMP-598; primary average particle size 13 μm, true specific gravity 0.97 ).
* 7: Silicone rubber powder B (fine powder of addition polymer of vinyl group-containing dimethylpolysiloxane and methylhydrogenpolysiloxane, manufactured by Shin-Etsu Chemical Co., Ltd .: KMP-594; primary average particle size 5 μm, true specific gravity 0.97 ).
* 8: 3-glycidoxypropyltrimethoxysilane (manufactured by Chisso Corporation: Silaace S-510).
* 9: Pentaerythritol tetrakis (3-mercaptobutyrate) (manufactured by Showa Denko KK: Karenz MT PE1).

Measurement of true specific gravity of silicone rubber powder:
The true specific gravity of the silicone rubber powder was measured by an immersion method (Archimedes method) using isopropyl alcohol in an atmosphere having an environmental temperature of 25 ° C. and a relative humidity of 25%.

Average particle size measurement:
The average particle diameter of the silicone rubber powder was determined from a photograph taken with an electron microscope.

Preparation of liquid crystal cell for evaluation:
As a spacer, 1 g of glass fiber having a diameter of 5 μm is added to each 100 g of the liquid crystal sealants of the examples and comparative examples, mixed and defoamed, and filled into a syringe. Further, an alignment film solution (PIA-5540-05A; manufactured by Chisso Corporation) was applied to a glass substrate with an ITO transparent electrode, baked, and rubbed. The liquid crystal sealant of Examples and Comparative Examples previously filled in a syringe on this substrate was applied with a seal pattern and a dummy seal pattern using a dispenser (SHOTMASTER 300: manufactured by Musashi Engineering Co., Ltd.), and then liquid crystal (JC-5015LA Small droplets manufactured by Chisso Corporation) were dropped into the frame of the seal pattern. Further, an in-plane spacer (NATOCO spacer KSEB-525F; manufactured by NATCO Corporation; gap width of 5 μm after bonding) is sprayed on another glass substrate that has been subjected to rubbing treatment, thermally fixed, and in a vacuum using a bonding apparatus. The substrate was bonded to the liquid crystal dripped substrate. After opening to the atmosphere and forming a gap, it was put into an oven at 120 ° C. and cured by heating for 1 hour to prepare a liquid crystal test cell for evaluation.

Table 2 shows the results of observing the seal shape and liquid crystal alignment disorder (evaluation of liquid crystal contamination) of the prepared liquid crystal cell for evaluation with a polarizing microscope. In addition, Table 2 shows the results of measuring the gap of the manufactured liquid crystal cell using a liquid crystal characteristic evaluation apparatus (OMS-NK3: manufactured by Chuo Seiki Co., Ltd.). Evaluation of the seal shape, liquid crystal alignment disorder, and the gap of the liquid crystal cell was made into the following four stages.

Evaluation of seal shape:
○: There is no disturbance in the linearity of the seal.
[Delta]: Deformation of the seal is recognized, but there is no problem in sealing the liquid crystal.
X: A level at which liquid crystal is inserted into the seal and a problem may occur in sealing the liquid crystal.
XX: The seal is broken and a cell cannot be formed.

Evaluation of liquid crystal cell gap:
A: The cell gap is uniformly 5 μm.
Δ: There is a place where a gap of about 5.5 μm is not formed in the cell.
X: There is a place where a gap of 6 μm or more does not appear in the cell.
XX: The seal is broken and a cell cannot be formed.

Evaluation of liquid crystal alignment:
○: There is no alignment disorder in the vicinity of the seal.
Δ: There is a slight disorder in the alignment of the liquid crystal in the vicinity of the seal.
X: There is disorder in alignment of liquid crystal in the vicinity of the seal.
XX: The seal is broken and a cell cannot be formed.

As shown in Table 2, the liquid crystal sealants of the examples according to the present invention can be applied to a thermosetting liquid crystal dropping method. In Comparative Example 1, since the silicone rubber particle size is small, the liquid crystal is inserted into the seal or the seal line is unstable. In Comparative Example 2, the curing is slow and insufficient, so that the contamination of the resin to the liquid crystal cannot be suppressed. In Comparative Example 3, the seal is broken and the cell cannot be manufactured.

Liquid crystal sealant adhesive strength test [adhesive strength (after curing at 120 ° C. for 1 hour)]:
1 g of glass fiber having a diameter of 5 μm is added as a spacer to 100 g of the liquid crystal sealant and mixed and stirred. This liquid crystal sealant was applied onto a 50 mm × 50 mm glass substrate, a 1.5 mm × 1.5 mm glass piece was bonded onto the liquid crystal sealant, and cured by placing in a 120 ° C. oven for 1 hour. The shear adhesive strength of the glass piece was measured using a bond tester (SS-30WD: manufactured by Seishin Shoji Co., Ltd.). The results of adhesive strength (after curing at 120 ° C. for 1 hour) are shown in Table 3.

Liquid crystal sealant moisture-resistant adhesive strength test [adhesive strength (after PCT)]:
The same measurement sample as the liquid crystal sealant adhesive strength test is prepared. The measurement sample was put into a pressure cooker test (PCT) machine (TPC-411: manufactured by Tabay Espec Co., Ltd.) for 20 hours under the conditions of 121 ° C., 2 atm, and humidity of 100%, and the shearing of the sample after the lapse of 20 hours. The adhesive strength was measured using a bond tester (SS-30WD: manufactured by Seishin Shoji Co., Ltd.). The results of adhesive strength (after PCT) are shown in Table 3.

Pot life (vs. initial viscosity increase):
Using an R-type viscometer (manufactured by Toki Sangyo Co., Ltd.), the obtained liquid crystal sealant was stored at 25 ° C. for 1 day, and then its viscosity (hereinafter sometimes referred to as “viscosity after 1 day”) was measured. The increase rate (pot life) from the viscosity immediately after production (hereinafter sometimes referred to as “initial viscosity”) was calculated. Table 3 shows the initial viscosity value (Pa · s) and the pot life value (%). The pop life is a value calculated by the following equation (5).
Pot life = (viscosity after 1 day−initial viscosity) / (initial viscosity) × 100 (5)

As shown in Table 3, the liquid crystal sealants of the examples according to the present invention are excellent in initial and moisture-resistant adhesive properties, have little change in viscosity, and have good workability.

The liquid crystal sealing agent for thermosetting liquid crystal dropping method of the present invention can be used for the production of liquid crystal display cells.

Claims (8)

A curable resin (a) which is an epoxy resin and a (meth) acrylated epoxy resin, a polyfunctional hydrazide compound (b), a curing accelerator (c), an inorganic filler (d), and a true specific gravity of 0.95 to 1 0.0, a silicone rubber powder (e) having an average particle diameter of 10 to 18 μm is contained as an essential component, and the content of the silicone rubber powder (e) is 5 to 40% by mass in the liquid crystal sealant Liquid crystal sealant for liquid crystal dripping method. The liquid crystal sealing agent for thermosetting liquid crystal dropping method according to claim 1, wherein the silicone rubber powder (e) is a fine powder of an addition polymer of vinyl group-containing organopolysiloxane and organohydrogenpolysiloxane. The liquid crystal sealant for a thermosetting liquid crystal dropping method according to claim 1 or 2, wherein the polyfunctional hydrazide compound (b) is a polyfunctional hydrazide compound having an isocyanuric ring skeleton represented by the following general formula (1).

(In Formula (1), R ¹ to R ³ are each independently a hydrogen atom or a molecular skeleton represented by Formula (2) below, and at least any two of R ¹ to R ³ are represented by Formula (2) ) Represents a group represented by

(In formula (2), n represents an integer of 1 to 6) The liquid crystal sealing agent for thermosetting liquid crystal dropping method according to any one of claims 1 to 3, wherein the inorganic filler (d) is at least one of alumina and silica. The liquid crystal for thermosetting liquid crystal dropping method according to any one of claims 1 to 4, wherein the curing accelerator (c) is a polyvalent carboxylic acid compound having an isocyanuric ring skeleton represented by the following general formula (3). Sealing agent.

(In formula (3), T ¹ to T ³ are each independently a hydrogen atom or a molecular skeleton represented by the following formula (4), and at least any two of T ¹ to T ³ are represented by formula (4 ) Represents a group represented by

(In formula (4), n represents an integer of 1 to 6) The liquid-crystal sealing compound for thermosetting liquid crystal dropping methods as described in any one of Claims 1 thru | or 5 containing a polythiol compound. The liquid-crystal sealing compound for thermosetting liquid crystal dropping methods as described in any one of Claims 1 thru | or 6 containing a coupling agent. A liquid crystal display cell sealed with a cured product of the liquid crystal sealant according to any one of claims 1 to 7.