JPH11119228A - Color spacer for liquid crystal display device, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly and uniformly disperse carbon black and to obtain high blackness degree, accuracy of particle size and brightness of an image by subjecting a compsn. for suspension polymn. containing polymerizable monomers. carbon black and a specified dispersant to suspension polymn. in an aq. medium. SOLUTION: This color spacer is obtd. by subjecting a compsn. for suspension polymn. containing polymerizable monomers, carbon black and a dispersant expressed by the formula to suspension polymn. in an aq. medium. In the formula, R is an alkyl group, alkoxy group or substd. or unsubstd. heterocyclic group, n is an integer 1 to 6. The polymerizable monomer is not limited, for example, unsatd. carboxylic acid such as acrylic acid, methacrylic acid, maleic acid which may be used as a single acid or a combination of two or more acids. The carbon black is not limited as far as it is smaller than the particle size of the obtd. polymer fine particles, and for example, a powder carbon black prepared by surface treatment of a powder carbon black with a silane coupling agent can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored spacer for a liquid crystal display device and a liquid crystal display device, and more particularly, to a colored spacer for a liquid crystal display device having excellent light-shielding properties and a liquid crystal display device having improved image visibility. About.

[0002]

2. Description of the Related Art Liquid crystal display devices are widely used in personal computers, portable electronic devices, and the like, but are liable to cause blurring of images particularly on colored screens. At present, it is desired to further improve the visibility of an image by removing the cause of blurring of the image and increasing the display contrast. JP-A-57-189117 discloses that in a liquid crystal display element in which liquid crystal is sealed in a liquid crystal cell in which two transparent substrates with electrodes are opposed to each other, colored spacers are scattered over the entire surface of the substrate in contact with the liquid crystal. Accordingly, a technique for preventing a reduction in display contrast of an image has been disclosed.

A spacer for a liquid crystal display element used for a liquid crystal display element requiring such a high contrast is required to be colored dark in order to prevent scattering of incident light. It is known that the above-mentioned colored spacer for a liquid crystal display element is produced by a method of coloring previously produced polymer fine particles, a method of coloring in the step of producing the polymer fine particles, and the like.

[0004] As a method for coloring previously prepared high molecular weight polymer particles, for example, Japanese Patent Application Laid-Open No. 1-144429 discloses a method in which high molecular weight polymer particles are treated with an acid and then colored. And JP-A-1-207.
No. 719 discloses high molecular weight polymer particles of 200-700.
There is disclosed a method of producing a fire-resistant baked product by heat treatment in a temperature range of ℃, and Japanese Patent Application Laid-Open No. 5-165033 discloses a method of coating polymer fine particles with a conjugated polymer such as polyacetylene. Have been.

Further, Japanese Patent Application Laid-Open No. 4-15623 discloses a method of driving ultrafine black metal oxide particles on the surface of high molecular weight polymer particles.
In the publication, after dispersing high-molecular polymer fine particles containing an anionic functional group in an oxidizing agent solution and adsorbing or impregnating the oxidizing agent, at least one of a heterocyclic five-membered ring compound and an aromatic hydrocarbon is used. A method for chemical oxidative polymerization by adding a compound is disclosed in Japanese Patent Publication No. 27242/1992, which discloses a water-soluble polymer fine particle obtainable by polymerizing an ethylenically unsaturated sulfonic acid or a salt thereof. A method of dyeing using a basic dye is disclosed.

Further, Japanese Patent Laid-Open Publication No.
A method of coloring high molecular weight polymer particles of an amino resin with an acid dye at a high temperature in the presence of a solvent is disclosed.
No. 3,633,331 discloses a method of coloring by mixing a dye emulsion in which an oil solvent solution of an oil dye is finely dispersed in an aqueous medium, and a high molecular polymer fine particle emulsion.

However, such a method of coloring previously produced high molecular weight polymer particles requires a complicated additional process for coloring newly prepared high molecular weight polymer particles. In addition, the production cost is increased, and the control of the performance and quality of the obtained colored high molecular weight polymer particles is accompanied by difficulties.

[0008] As a method of coloring in the step of producing high molecular polymer particles, for example, Japanese Patent Publication No. 50-33821
In JP-A No. 2-2, a pigment is dispersed in a water-insoluble liquid resin or a water-insoluble resin solution such as ester gum, rosin, petroleum resin, cumarone resin, indene resin, epoxy resin, and styrene resin, and then polymerizable monomer The solution to which the body has been added is, if necessary, a known water-soluble protective colloid substance such as a nonionic, cationic, anionic surfactant, polyvinyl alcohol, carboxymethylcellulose, polyoxyethylene glycol, and sodium acrylate; There is disclosed a method for producing a colored powdery coating composition which is emulsified in water using ammonia or amines such as ammonia, monoethanolamine, diethanolamine, and triethanolamine, and then polymerized by a radical initiator.

However, the dispersibility of the pigment in the individual particles of the colored powdery coating composition disclosed in Japanese Patent Publication No. 50-33821 is not so good.
If it is a coating composition such as a paint, since it is applied to a relatively thick film, even if the dispersibility of the above pigment may not be a practical problem, it may be used for a liquid crystal display element. However, the use of such a spacer cannot improve the visibility of the image. Furthermore, the distribution of the individual particles of the colored powdery coating composition becomes broad, and as a spacer for a liquid crystal display device, the particle size accuracy is extremely poor, and it is not completely usable, and Corresponding to such powdery coating composition with poor particle size accuracy by classification,
It cannot be said that it is industrially impossible to form a spacer for a liquid crystal display element.

Japanese Patent Publication No. 50883/1981 discloses a suspension polymerization of a polymerizable composition comprising a polymerizable monomer, an inorganic dispersant and a black colorant. There is disclosed a method for producing fine spherical polymer particles containing a black colorant and having a uniform particle size distribution by, for example, combining the dispersants so that the charges of the dispersants are opposite.

However, in the method for producing fine spherical polymer particles containing a black colorant and having a uniform particle size distribution disclosed in JP-B-56-50883, as described in the publication, Although it may be possible to prevent the coalescence of the polymer particles with the progress of polymerization, as described above, as a colored spacer for a liquid crystal display element, a black colorant is uniformly dispersed at a high concentration in the polymer particles, Improving the visibility of an image is extremely difficult.

Japanese Patent Application Laid-Open No. Hei 4-370160 discloses that a carbon black graft polymer obtained by reacting a polymer having at least one reactive group in a molecule with carbon black is a spherical fine particle comprising a polymer. Inside the
Thermoplastic resin composition, coating composition, thermal transfer ink ribbon coating agent, thermal transfer ink, curable resin composition, back coat for magnetic recording media dispersed in a state localized on the surface side portion of the particles Colorants such as agents, matting agents and charge control agents are disclosed.

The coloring agent, matting agent, and charge controlling agent used in the ink ribbon coating agent for thermal transfer and the back coating agent for magnetic recording media disclosed in Japanese Patent Application Laid-Open No. 4-370160 have strong light-shielding properties. If the carbon black is used, the content of carbon black for obtaining the required light-shielding degree may be small, and it is expected that the mechanical strength of the resulting coating will not be significantly reduced.

However, the dispersibility of carbon black in the above-mentioned spherical fine particles disclosed in Japanese Patent Application Laid-Open No. 4-370160 is not yet sufficient, and it cannot be used as a spacer for a light-shielding liquid crystal display element at all. .
When the suspension polymerizable monomer composition containing the polymerizable monomer and carbon black is subjected to suspension polymerization in an aqueous medium to produce the spherical fine particles, the dispersion state of carbon black with respect to the polymerizable monomer is It becomes a problem.

That is, in order to obtain spherical fine particles having an average particle size of 1 to 40 μm used for a spacer for a light-shielding liquid crystal display element, the particle size of carbon black must be smaller than the particle size of the polymer spherical fine particles. It is necessary to be. If the particle size of the carbon black is larger than the particle size of the polymer spherical fine particles, when a suspension droplet is prepared in an aqueous medium, the carbon black is detached from the suspension droplet to completely remove the carbon black. Suspension droplets that do not contain or carbon black content will be different suspension droplets,
The resulting polymer spherical fine particles have a large variation in the degree of blackening and have a low degree of blackening, and cannot be used as a spacer for a light-shielding liquid crystal display element.

[0016]

DISCLOSURE OF THE INVENTION The present inventors have made intensive studies on suspension droplets of a monomer composition for suspension polymerization having a high content of carbon black, and disclosed in Japanese Patent Application Laid-Open No. 5-70511. A specific dispersant for enhancing the dispersibility of carbon black in a monomer composition for suspension polymerization containing a monomer and carbon black, a suspension polymerization toner using the same, and a method for producing a suspension polymerization toner are disclosed. By applying the technology of a different field to the spacer for the light-shielding liquid crystal display element, the present inventors succeeded in obtaining polymer spherical fine particles having a high degree of blackening, small variation, and high particle size accuracy. Was completed.

The present invention provides a spacer for a liquid crystal display element in which carbon black is highly uniformly dispersed, the degree of blackening is high, and the particle size is high in accuracy, and a liquid crystal display element having improved image visibility. With the goal.

[0018]

According to the present invention, a composition for suspension polymerization comprising a polymerizable monomer, carbon black and a dispersant represented by the following formula (1) is suspended in an aqueous medium. A gist is a colored spacer for a liquid crystal display element characterized by being polymerized.

Embedded image [In the formula (1), R represents an alkyl group, an alkoxy group, a substituted or unsubstituted heterocyclic group, and n represents 1 to 6
Represents an integer. ]

The polymerizable monomer used in the present invention is not particularly limited, but examples thereof include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid. Saturated carboxylic acids; methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-acrylate
Acrylates such as -butyl, t-butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate;
N-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, dodecyl methacrylate,
Methacrylic esters such as glycidyl methacrylate, β-hydroxymethyl methacrylate, and β-hydroxyethyl methacrylate; styrenes such as styrene, vinyltoluene, α-methylstyrene, p-methylstyrene, t-butylstyrene, and chlorostyrene Monomer; diene monomer such as butadiene and isoprene; ethylene, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, vinyl stearate, acrylamide, methacrylamide, acrylonitrile, methylolacrylamide, acrylacetate, diallyl adipate Dimethyl itaconate, diethyl maleate, allyl alcohol, vinylpyridine, N-vinylpyrrolidone, N-hydroxyacrylamide, 2-vinyl-2-oxazoline, 2-isopropenyl-2 Oxazoline, dimethylaminoethyl acrylate, glycidyl methacrylate, allyl glycidyl ether, monomethyl fumarate, and the like. These may be used alone,
More than one species may be used in combination.

A crosslinking compound may be added to the polymerizable monomer. The crosslinkable compound is not particularly limited, and examples thereof include divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol diene. Alkylene polybasic unsaturated carboxylic esters such as (meth) acrylate, trimethylolpropane tri (meth) acrylate and 1,3-butanediol di (meth) acrylate; N, N-divinylaniline, divinyl ether, divinyl sulfide And divinyl compounds such as divinylsulfonic acid, and compounds having three or more vinyl groups. These may be used alone or in combination of two or more. The amount of the crosslinkable compound to be added is preferably 1 to 50 parts by weight based on 100 parts by weight of the polymerizable monomer.

The amount of the polymerizable monomer is preferably 1 to 200 parts by weight based on 100 parts by weight of the aqueous medium. If the amount of the polymerizable monomer is less than 1 part by weight, the polymerization efficiency is lowered. If the amount is more than 200 parts by weight, it is difficult to remove the heat of polymerization.

The carbon black is not particularly limited as long as it has a particle size smaller than that of the obtained polymer fine particles. For example, powdered carbon black and powdered carbon black may be used. Powdery carbon black treated with a surface treatment agent such as a silane coupling agent, a titanate coupling agent, or an aluminum coupling agent, is subjected to suspension polymerization with the above polymerizable monomer, and is grafted onto the obtained polymer. And treated carbon black. The pH of these carbon blacks is preferably from 6 to 10, more preferably from 7 to 9. If the pH of the carbon black is too low, radicals are trapped in the polymerization reaction, which may hinder the polymerization reaction and cause the polymerization composition to gel.

The amount of the carbon black is 0.1 to 200 parts by weight based on 100 parts by weight of the polymerizable monomer. If the amount of the carbon black is less than 0.1 part by weight, the obtained colored spacer for a liquid crystal display element is difficult to be colored with a high degree of blackening, and if it exceeds 200 parts by weight, the obtained colored spacer for a liquid crystal display element is obtained. May have a reduced mechanical strength.

The means for uniformly dispersing the carbon black in the polymerizable monomer is not particularly limited. For example, the carbon black is dispersed using a ball mill, a bead mill, a sand mill, an attritor, a sand grinder nanomizer, or the like. Method and the like. In order to uniformly disperse the polymerizable monomer and carbon black, a dispersant is added to a mixture of the polymerizable monomer and carbon black.

The dispersant used in the present invention has a structure represented by the above formula (1). In the above formula (1), R represents an alkyl group, an alkoxy group, a substituted or unsubstituted heterocyclic group, and n represents an integer of 1 to 6, for example, as shown in Tables 1 to 5 Compound Example No. 1 to No. 70 and the like.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

[Table 5]

The content of the dispersant is preferably 0.1 to 30 parts by weight based on 100 parts by weight of the polymerizable monomer. If the content of the dispersant is too small, the dispersing effect is reduced, and if it is too large, the dispersant may bleed out on the surface of the obtained polymer fine particles. In the above dispersant, inorganic salts of high-molecular-weight polycarboxylic acids, inorganic salts of long-chain polyaminoamidic acids, long-chain polyaminoamidates, high-molecular-weight unsaturated polycarboxylic acids, high-molecular-weight unsaturated acid esters, polyamides, high-molecular-weight Copolymers,
Other conventionally known dispersants such as esters of higher alcohols may be added. When the other dispersant is used in combination, the total content of the dispersant is the same as the case where the dispersant represented by the formula (1) is solely contained, based on 100 parts by weight of the polymerizable monomer. Preferably it is 0.1 to 30 parts by weight. The content of the other dispersant is preferably not more than 量 of the dispersant represented by the above formula (1).

The aqueous medium is not particularly limited, but may be, for example, water; polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, gelatin, methylcellulose, polymethacrylamide, polyethylene glycol,
Aqueous solutions such as polyethylene oxide monostearate, sorbitan tetraoleate, glycerin monooleate, dodecylbenzene sulfonic acid, and the like can be given.

In the aqueous medium, a composition for suspension polymerization comprising a polymerizable monomer, carbon black and a dispersant represented by the above formula (1) is suspended in fine particles. The means for suspending the composition for suspension polymerization in the form of fine particles is not particularly limited, and examples thereof include a method of dispersing the composition using a homogenizer or the like.

At the time of the fine particle suspension of the composition for suspension polymerization, a suspension stabilizer may be added. Examples of the suspension stabilizer include, but are not particularly limited to, water-soluble polymers such as polyvinyl alcohol, starch, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, and sodium polymethacrylate; barium sulfate, calcium sulfate, and sulfuric acid. Examples include aluminum, calcium carbonate, calcium phosphate, talc, clay, diatomaceous earth, and other metal oxide powders. The addition amount of the suspension stabilizer is preferably about 0.01 to 20% by weight based on the polymerizable monomer.

By the above-mentioned dispersion, carbon black is finely dispersed in the composition for suspension polymerization containing a polymerizable monomer and carbon black, and the primary particles or particles having a particle size close to 0.1%.
When the composition for suspension polymerization is suspended in an aqueous medium, it is surely dispersed in the suspension droplets having a small particle diameter because the particles are uniformly dispersed to a small particle diameter of about 0.5 to 0.5 μm. The carbon black is taken in and uniformly dispersed at a high concentration.

Then, the composition for suspension polymerization containing the above polymerizable monomer, carbon black and the dispersant represented by the above formula (1) is subjected to suspension polymerization in an aqueous medium to obtain a fine spherical liquid crystal. A colored spacer for a display element is manufactured.

The polymerization initiator used in the suspension polymerization is as follows:
Although not particularly limited, for example, 2,2′-azobisisobutyronitrile, 2, ′ 2-azobis-2,
4'-dimethylvaleronitrile, 2,2'-azobis-
Methylbutyronitrile, 2,2'-azobis-methylheptonitrile, 2,2'-azobis-2,3-dimethylbutyronitrile, 2,2'-azobis-2,3,3-trimethylbutyronitrile Azo compounds such as 4,4'-azobis-4-cyanovaleric acid, dimethyl-2,2'-azobisisobutyrate; acetyl peroxide, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, octanoyl peroxide , O-methoxybenzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, acetylcyclohexylsulfonyl peroxide, t-butyl perisobutyrate, t-butyl perivanate, 2-ethylhexane peroxide T-butyl acid, di-t-butyl peroxide, di-t-butyl cumyl peroxide, dicumyl peroxide, methylethyl ethyl ketone peroxa Monofunctional peroxides such as tert-butyl, cumene hydroperoxide and t-butyl hydroperoxide; t-butylperoxy-3,5,5-trimethylhexanoate, dibutylperoxyhexahydroterephthalate, bis (t-butyl) Peroxy) isophthalate, di-t-butylperoxytrimethyl adipate, 3,3,4,4-tetra (t-butylperoxycarbonyl) benzophenone, 2,5-dimethyl-
2,5-dimethyl-2,5-bis (m-toluoylperoxy) hexane, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, 2,5-dimethyl-2,5-bis (Ethylhexanoylperoxy) hexane, 1,6-bis (t-butylperoxycarbonyloxy) hexane, 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, 1,1 −
Bis (t-hexylperoxy) cyclohexane, 1,
1-bis (t-butylperoxy) cyclohexane, di-t-butylperoxy-2-methylcyclohexane,
Di-3-methoxybutyl peroxydicarbonate, di-2-ethylhexylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, diisopropylperoxydicarbonate, diethylene glycol-bis (t-butylpercarbonate) ) And the like.

The amount of the polymerization initiator to be added is preferably 0.25 to 3 parts by weight based on 100 parts by weight of the polymerizable monomer. If the amount of the polymerization initiator is less than 0.25 parts by weight, the polymerization rate will be low, and it is unnecessary to add more than 3 parts by weight.

If the polymerization temperature of the above suspension polymerization is too low, the polymerization rate will be low, and if it is too high, it will be difficult to control the polymerization reaction, so it is preferably 20 to 100 ° C. In the above-mentioned polymerization temperature range, if the polymerization time is too short, the polymerization rate will decrease. It does not need to exceed 50 hours.

The microsphere colored spacer for a liquid crystal display element obtained by the above suspension polymerization is separated from the reaction product slurry by means such as filtration and centrifugation. The separated microsphere colored spacer for a liquid crystal display element is washed with water or the like, and then dried by heating or reduced pressure. The dried microsphere colored spacer for a liquid crystal display element can be classified, if necessary, to further narrow the particle size distribution.

The colored spacer for a liquid crystal display element of the present invention comprises:
Preferably, the average particle size is 0.5 to 50 µm, more preferably 1 to 40 µm. The average particle size is 0.5 μm
If the average particle diameter is less than 50 μm, aggregation tends to occur, and applications exceeding 50 μm are rare.

The colored spacer for a liquid crystal display element of the present invention comprises:
Preferably, the coefficient of variation of the particle size is 20% or less, more preferably 10% or less. The coefficient of variation of the particle size is 20%
When the ratio exceeds, the particle size distribution becomes too wide, and the performance as a colored spacer for a liquid crystal display element may be deteriorated.

The colored spacer for a liquid crystal display element of the present invention comprises:
If necessary, it may be coated with a coating agent such as a silane coupling agent. The coating with the coating agent is preferably performed with a thin film such as a monomolecular film of these coating agents.

Examples of the silane coupling agent include γ-aminopropyltrimethoxysilane, N-β-
(Aminoethyl) -γ-aminopropyltrimethoxysilane, 3- [N-allyl-N- (2-aminoethyl)]
Aminopropyltrimethoxysilane, 3- (N-allyl-N-glycidyl) aminopropyltriethoxysilane, 3- (N-allyl-N-methacryl) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl)
Amino-based silane coupling agents such as aminopropyltrimethoxysilane; N, N-bis [3- (methyldimethoxysilyl) propyl] amine; N, N-bis [3- (trimethoxysilyl) propyl] amine; N-bis [3- (methyldimethoxysilyl) propyl] ethylenediamine, N, N-bis [3- (trimethoxysilyl)
Propyl] ethylenediamine, N-glycidyl-N, N
Amide-based silane coupling agents such as -bis [3- (methyldimethoxysilyl) propyl] amine and N-glycidyl-N, N-bis [3- (trimethoxysilyl) propyl] amine; vinyltriethoxysilane, vinyl- Vinyl silane coupling agent such as tris (2-methoxyethoxy) silane; methacrylic silane coupling agent such as γ-methacryloxypropyltrimethoxysilane; γ
A glycidyl-based silane coupling agent such as glycidoxypropyltrimethoxysilane; a mercapto-based silane coupling agent such as γ-mercaptopropyltrimethoxysilane;

The means for coating the colored spacer for a liquid crystal display element with the coating agent is not particularly limited. For example, the coating agent and the colored spacer for a liquid crystal display element may be coated with an inorganic solvent such as water or alcohol or an organic solvent. In a mixture, heated under stirring to form a film on the colored spacer for a liquid crystal display element, and thereafter, an inorganic solvent or an organic solvent is removed together with excess coating agent by decantation or the like, followed by drying under reduced pressure. A method in which the coating agent and the colored spacer for a liquid crystal display element are mixed and heated and stirred to form a film on the colored spacer for a liquid crystal display element.

According to a second aspect of the present invention, there is provided a liquid crystal display element characterized in that the colored spacer for a liquid crystal display element according to the first aspect is interposed between two opposing transparent substrates with electrodes. It is assumed that.

The transparent substrate used in the present invention is not particularly limited. For example, a soda lime glass substrate, an alkali-free glass substrate, a borosilicate glass substrate, a quartz A glass substrate, a silicon substrate, and the like can be given. The thickness of these transparent substrates is generally 1.1 mm, 0.7 mm,
0.5 mm, 0.4 mm or the like is used, but is not limited to this. The external dimensions of the transparent substrate are
It is cut into various dimensions depending on the use of the liquid crystal display element.

The surface of these transparent substrates is smooth, and when the colored spacer for a liquid crystal display element according to claim 1 is interposed between two substrates, a liquid crystal filling space having the same thickness can be formed. It maintains parallelism and has substantially no surface scratches, bubbles and foreign substances, has a surface roughness expressed by JIS standards, has no waviness or warpage, and has a liquid crystal orientation. , Which do not affect the cutting of the pattern edge. In addition, the transparent substrate is required to have thermal properties such as heat resistance, thermal shock resistance, thermal expansion and contraction, thermal expansion coefficient, cleanliness, and the like.

The electrode is made of a transparent conductive film, and includes, for example, an indium oxide film and a tin oxide film doped with tin oxide.
It can be widely used as an electrode for liquid crystal display from a high resistance region (200 Ω / □ or more) to a low resistance region (10 Ω / □) as a crystalline transparent film by a thermal spray method or the like.

The liquid crystal display element cell is formed by interposing the colored spacer for a liquid crystal display element according to claim 1 between the two opposing transparent substrates with electrodes thus obtained. Liquid crystal is filled in the parallel space formed by the display element colored spacers, and other necessary components such as a polarizer, a backlight, and a driving IC are mounted.
A liquid crystal display device is manufactured.

The colored spacer for a liquid crystal display device according to the first aspect of the present invention is, as described above, a suspension spacer containing a polymerizable monomer, carbon black, and a dispersant represented by the above formula (1). The composition is obtained by suspension polymerization in an aqueous medium.Carbon black is contained in a high concentration in individual particles of the polymer, and is uniformly dispersed, so that the degree of blackening is high, A colored spacer for a liquid crystal display element having a very small variation in the degree of blackening and a high-precision particle size having a sharp particle size distribution.

Since the liquid crystal display element according to the second aspect uses the colored spacer for the liquid crystal display element according to the first aspect, scattering of incident light or the like is prevented, and an image is blurred. Since there is no light and there is little refraction of light that causes image distortion, an image that is multicolored can be projected on a screen with high fidelity with high fidelity.

[0053]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 60 parts by weight of tetramethylolmethane triacrylate, 20 parts by weight of divinylbenzene and 20 parts by weight of acrylonitrile were uniformly mixed, and 5 parts by weight of carbon black surface-coated with polyethylene was added to the mixture. Compound Example No. 1 shown in No. 1 7. dispersant
The mixture was added together with 2 parts by weight, and uniformly mixed and dispersed by using a bead mill for 48 hours to obtain a composition for colored suspension polymerization containing carbon black.

2 parts by weight of benzoyl peroxide was added to the obtained composition for colored suspension polymerization containing carbon black, and the mixture was mixed uniformly. This was mixed with a suspension stabilizer of polyvinyl alcohol at a concentration of 3% by weight. The mixture is charged into 850 parts by weight of an aqueous solution of polyvinyl alcohol and stirred sufficiently, and then stirred and colored using a homogenizer until the droplet diameter of the composition for colored suspension polymerization becomes fine particles in the range of 3 to 10 μm. A suspension of the composition for suspension polymerization was prepared.

The obtained suspension of the colored suspension polymerization composition was transferred to a 2-liter separable flask equipped with a thermometer, a stirrer and a reflux condenser, and heated to 85 ° C. while stirring in a nitrogen atmosphere. Heat, heat at the same temperature for 7 hours,
The temperature was raised to 0 ° C., and the mixture was heated at the same temperature for 3 hours to carry out a polymerization reaction. Thereafter, the polymerization reaction solution is cooled, and the generated colored fine particles are filtered, washed with water, and dried, and then only coarse particles are classified and removed. The average particle size is 5.55 μm, and the variation coefficient of the particle size is 2.48. % Of a colored spacer for a liquid crystal display element was obtained.

On a glass plate having a thickness of 0.7 mm, a transparent conductive film of indium oxide-tin oxide having a thickness of 500 ° was formed by low-temperature sputtering, and then a predetermined electrode pattern was formed by photolithography. Next, from above the electrode pattern, an alignment agent is applied to a glass plate, heated to form an alignment control film, and then cut, and 5 cm × 12.5 cm
Of a transparent substrate with electrodes,
An epoxy-based adhesive mixed with a glass fiber spacer was printed along the periphery by screen printing with a width of 1 mm, and the obtained colored spacer for a liquid crystal display element was applied on a glass plate surrounded by the epoxy-based adhesive. Spraying was performed uniformly using a pressurized nitrogen gas to about 150 particles / mm ² by a spraying method.

A new transparent substrate with electrodes is superimposed on the transparent substrate with electrodes on which the colored spacers for liquid crystal display elements are scattered, and a load of 1 kg / cm ² is uniformly applied to the entire surface of the transparent substrate with electrodes by a press machine. At the same time at 160 ° C
The above-mentioned epoxy-based adhesive was cured by heating for 0 minutes to produce a cell for a liquid crystal display device.

The obtained liquid crystal display element cell is evacuated using a vacuum pump from an injection hole provided in a part of the seal portion of the epoxy-based adhesive, and the inside is evacuated. Sealing the seal portion in a state where the pressure in the liquid crystal display element cell is 0.6 atm lower than the atmospheric pressure,
The injected liquid crystal was heated to a predetermined temperature, and the liquid crystal was subjected to a reorientation process, thereby producing a TN type liquid crystal display device.

Examples 2 to 4 Coloring for a liquid crystal display element was performed in the same manner as in Example 1 except that the composition of the polymerizable monomer and the type of the dispersant were changed as shown in Table 6. A spacer and a liquid crystal display element were manufactured.

(Comparative Example 1) Carbon black having no polyethylene coating on the surface was used in place of the carbon black of Example 1, and the dispersant was an ester of a higher alcohol (polyoxyethylene lauryl ether, manufactured by Kao Corporation; A colored spacer for a liquid crystal display element and a liquid crystal display element were produced in the same manner as in Example 1, except that the product name was changed to "Emulgen 104P").

(Comparative Example 2) The carbon black of Example 1 was not used, and the dispersant was changed to an azine compound (Nigrosine, trade name "Bontron N-04", manufactured by Orient Chemical Co., Ltd.). Except for the above, a colored spacer for a liquid crystal display element and a liquid crystal display element were produced in the same manner as in Example 1.

To evaluate the performance of the colored spacers for liquid crystal display elements and the liquid crystal display elements obtained in Examples 1 to 4 and Comparative Examples 1 and 2, [1] the average particle diameter and the particle size of the colored spacers for liquid crystal display elements Coefficient of variation of diameter, blackness (light transmittance)
And impurity concentration (a) sodium ion, (b) potassium ion, (c) chloride ion, (d) sulfate ion,
[2] The average cell gap, presence / absence of color unevenness, and light-shielding property of the liquid crystal display element were tested by the following methods.
The test results are shown in Table 6.

[1] Quality of colored spacer for liquid crystal display element: Average particle size: Coulter counter BZ / C-1000
The particle size was measured using a mold (manufactured by Coulter), and the average particle size was calculated.

Coefficient of variation of particle diameter: The value obtained by dividing the standard deviation of the particle diameter by the average particle diameter from the result of the particle diameter measurement described in the preceding section was expressed in%.

Blackness (light transmittance): A 1 mm-thick film obtained by polymerizing a polymerization composition comprising a mixture of a polymerizable monomer and a coloring substance having the same composition as a spacer for a liquid crystal display element under the same conditions. A plate-like body was prepared, and the plate-like body was measured for spectral transmittance at all wavelengths in the visible region at a wavelength of 400 to 700 nm using a spectrophotometer, and the maximum value was taken as the blackness of the spacer for a liquid crystal display element. .

Impurity concentration: 10 g of the obtained liquid crystal display element spacer was mixed with a mixed solvent (water / isopropanol = 7).
(3/3 volume ratio) into 330 ml with stirring.
It was left for a week (while stirring once a day). For the last two days, the liquid crystal display element spacer was settled down. The supernatant was filtered, and the filtrate was concentrated to 30 ml for analysis. For sodium ions and potassium ions, SPQ8000 type atomic absorption spectrophotometer (Jarrell.
(Ash Co.). Chloride ions and sulfate ions were analyzed using a 2010I ion chromatography analyzer (manufactured by Dionex).

[2] Quality of liquid crystal display element: average cell gap: liquid crystal cell gap measuring device TFM
The liquid crystal cell gap was measured using a -120AFT type (manufactured by Oak Manufacturing Co., Ltd.), and the average cell gap was calculated.

Presence or absence of color unevenness: A polarizing sheet is superimposed on both sides of the TN liquid crystal display element so that the color tone of the reflected light of the obtained TN liquid crystal display element has an olive color.
The presence or absence of color unevenness of the TN-type liquid crystal display element is visually observed. ◎: No color unevenness is observed at all, ：: Some color unevenness is recognized depending on the conditions, but a degree that does not cause a problem in practical use. X: Color unevenness was recognized, which was not practically acceptable.

Light-shielding property: The polarizing sheet to be affixed to the obtained TN-type liquid crystal display element was set to a normal black mode, and the black portion at the center of the spacer for the liquid crystal display element and the liquid crystal portion where no spacer was present when the driving voltage was turned off. Is compared with 10 observers with a transmission microscope having a magnification of 200 times, and it is determined that the blackness of the central portion of the liquid crystal display element spacer is darker than or equal to the blackness of the liquid crystal portion where no spacer exists. Recognized number of people: ◎: 8 or more, ○: 7
の も の: 5-6 people, ×: 4 or less,
Was evaluated in four steps.

[0071]

[Table 6]

[0072]

As described above, the colored spacer for a liquid crystal display element according to the first aspect of the present invention contains carbon black in a high concentration and is uniformly dispersed in individual polymer particles. Therefore, the degree of blackening is high, the variation of the degree of blackening is extremely small, and the particle size distribution is sharp and highly accurate.

Since the liquid crystal display element according to the second aspect of the present invention uses the colored spacer for the liquid crystal display element according to the first aspect of the present invention, scattering of incident light and the like are prevented and an image is blurred. Since there is no light and there is little refraction of light that causes image distortion, an image that is multicolored can be projected on a screen with high fidelity with high fidelity.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one example of a liquid crystal display device of the present invention.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Transparent electrode 3 Alignment control film 4 Colored spacer for liquid crystal display elements 5 Sealing member 6 Nematic liquid crystal 7 Polarizing sheet

Claims (2)

[Claims] 1. A suspension polymerization composition comprising a polymerizable monomer, carbon black and a dispersant represented by the following formula (1), which is obtained by suspension polymerization in an aqueous medium. Colored spacers for liquid crystal display devices. Embedded image [In the formula (1), R represents an alkyl group, an alkoxy group, a substituted or unsubstituted heterocyclic group, and n represents 1 to 6
Represents an integer. ] 2. A liquid crystal display device, wherein the colored spacer for a liquid crystal display device according to claim 1 is interposed between two opposing transparent substrates with electrodes.