JP2888738B2 - Colored polymer fine particles, method for producing the same, spacer for liquid crystal display element, and liquid crystal display element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored polymer fine particle used as a labeling material, a carrier for a diagnostic reagent, a spacer for a liquid crystal display device, a method for producing the same, and a spacer for a liquid crystal display device and a liquid crystal display device.

[0002]

2. Description of the Related Art It is conventionally known to produce colored polymer fine particles by subjecting a polymerizable monomer to suspension polymerization in an aqueous medium in the presence of a pigment. As the polymerizable monomer, a monofunctional vinyl compound is generally used.

However, it is difficult to uniformly disperse the pigment inside the polymer fine particles according to this type of conventional technology, and it is not possible to obtain dark and uniformly colored polymer fine particles.
Further, the mechanical strength and the solvent resistance (the property that the pigment is not extracted by the organic solvent) are poor.

In Japanese Patent Publication No. 4-59321, a polyfunctional vinyl compound is used as a polymerizable monomer, and 100 to 15% by weight of the polyfunctional vinyl compound is used as the polymerizable monomer. A pigment (filler) treated to impart lipophilicity is mixed with a monomer composed of 0 to 85% by weight of a lipophilic vinyl compound, and subjected to suspension polymerization in an aqueous medium to give a colored polymer. A pre-process for obtaining microparticles is disclosed.

[0005] The above-mentioned patent publication discloses that the surface of the colored polymer fine particles is subjected to suspension polymerization or emulsion polymerization of the vinyl polymer compound in the presence of the colored polymer fine particles obtained in the above-mentioned previous step. The present invention discloses a colored polymer fine particle coated with a polymer of the present invention, whereby the pigment (filler) is not substantially present on the surface of the polymer fine particle.

On the other hand, Japanese Patent Application Laid-Open No. 57-189117 discloses a liquid crystal display device in which two transparent substrates with electrodes are arranged so that the electrodes face each other, and liquid crystal is sealed in the gap between the substrates. There is disclosed an invention relating to a liquid crystal display element in which colored spacers such as colored plastic fine particles are scattered all over the substrate in contact with the liquid crystal in the liquid crystal display, thereby preventing the display contrast of the liquid crystal display element from lowering.

[0007]

However, in the former invention, the colored polymer fine particles obtained in the preceding step are:
Although improvements in mechanical strength, pigment dispersibility and solvent resistance have been observed, they have not yet been fully satisfactory.

Further, in order to prevent the pigment from being substantially present on the surface of the polymer fine particles, a vinyl compound is subjected to suspension polymerization or emulsion polymerization in the presence of the colored polymer fine particles in a subsequent step. The polymerization process becomes two steps, and the production cost becomes high.

[0009] Further, an attempt was made to produce a liquid crystal display element using the above colored polymer fine particles as the colored spacer in the latter invention. However, since the dispersibility of the pigment in the colored polymer fine particles was insufficient, the liquid crystal display element was not used. A decrease in display contrast of the display element could not be prevented well.

[0010] The existing colored spacers composed of various colored plastic fine particles have a low coloring concentration of fine particles or uncolored fine particles mixed with the colored fine particles, and all of them lower the display contrast of the liquid crystal display element. Could not be successfully prevented.

The present invention solves the above-mentioned problems. It is an object of the present invention to disperse the pigment uniformly in the polymer fine particles and to color the polymer finely, and to provide excellent mechanical strength and solvent resistance. (Pigment is not extracted by organic solvent)
And a method for producing the same.

Another object of the present invention is to provide a spacer for a liquid crystal display element which can favorably prevent a decrease in display contrast of the liquid crystal display element, and a liquid crystal display element using the spacer for the liquid crystal display element. It is in.

[0013]

In order to achieve the above object, the colored polymer fine particles of the present invention comprise 100 to 60% by weight of a compound having three or more ethylenically unsaturated groups and two ethylenically unsaturated groups. Pigments are uniformly dispersed in polymer fine particles obtained by polymerizing 100 parts by weight of a monomer comprising a compound having a saturated group from 0 to 40% by weight and 5 to 50 parts by weight of (meth) acrylonitrile. Things.

Further, the method for producing colored polymer fine particles of the present invention is characterized in that the compound having three or more ethylenically unsaturated groups is 100 to 60% by weight and the compound having two ethylenically unsaturated groups is 0 to 40% by weight. % Of the monomer, 5 to 50 parts by weight of (meth) acrylonitrile, and a pigment, and the mixture is suspended in an aqueous medium in the form of fine particles for polymerization.

[0015] The spacer for a liquid crystal display element of the present invention comprises:
It comprises the above colored polymer fine particles or the colored polymer fine particles obtained by the above production method.

A liquid crystal display device according to the present invention is obtained by using the above-described spacer for a liquid crystal display device.

The compound having three or more ethylenically unsaturated groups used in the present invention includes tetramethylolmethanetetra (meth) acrylate, tetramethylolmethanetri (meth) acrylate, trimethylolpropanetetra (meth) acrylate, Pentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerol tri (meth) acrylate, triallyl (iso) cyanurate,
Triallyl trimellitate and the like can be mentioned.

The compound having two ethylenically unsaturated groups used in the present invention includes divinylbenzene,
1,4-divinyloxybutane, divinyl sulfone, diallyl phthalate, diallyl acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerol di (Meth) acrylate and the like.

In the present invention, the compound having three or more ethylenically unsaturated groups is 100 to 60% by weight, preferably 90 to 70% by weight, and the compound having two ethylenically unsaturated groups is preferably 0 to 70% by weight. ~ 40% by weight, preferably 1
A monomer consisting of 0 to 30% by weight is used.

When the amount of the compound having three or more ethylenically unsaturated groups is less than 60% by weight, the crosslinked structure of the polymer is reduced, and the mechanical strength and solvent resistance of the obtained colored polymer fine particles are reduced. On the other hand, when the number of compounds having three or more ethylenically unsaturated groups increases, the polymerizability tends to decrease. In order to improve the polymerizability and adjust the degree of crosslinking of the polymer, two ethylene groups are used. In some cases, the compound having an unsaturated group is used in an amount of 40% by weight or less.

Further, the type of the above-mentioned monomer and the amount thereof are extremely important. If the ratio is out of this range, the pigment may be contained in the monomer even if an appropriate amount of (meth) acrylonitrile described later is used. It becomes difficult to disperse uniformly.

(Meth) acrylonitrile is used in an amount of 5 to 50 parts by weight, preferably 10 to 40 parts by weight, based on 100 parts by weight of the total of the above monomers. If the amount of (meth) acrylonitrile used is less than 5 parts by weight, the dispersibility of the pigment in the monomer will decrease, and if the amount of (meth) acrylonitrile exceeds 50 parts by weight, the ethylenically unsaturated group And the mechanical strength of the resulting colored polymer fine particles decreases.

The pigment used in the present invention may be any of commercially available ordinary organic pigments and inorganic pigments, and these pigments may be used alone or in combination of two or more. . The average particle diameter of the pigment is preferably 1 micron or less, more preferably 0.05 to 0.5 μm.

As organic pigments, quinacridone red,
Para Red, Chlorinated Para, Litol Rubin, Pigment Scar Red, Madder Lake, Alizarin Maroon, Helio Bordeaux, Thioindigo, Toluidine Maroon, Carbazole Dioxazine Violet, Red Lake C, Pyrazolone Red, Naphthol Red, Anthraquinone Red, Isoindolinone Red, Anthraquinone Yellow , Benzidine yellow, hanza yellow, benzidine yellow toluidine, benzidine orange, disazo red, dianisidine orange, pyranthrone orange, GR perinone orange, isoindolinone yellow, flavanthrone yellow, anthrapyrimidine yellow, nickel azo yellow, phthalocyanine blue,
Examples include phthalocyanine green, pigment green B, indanthrone blue, aniline black and the like.

As inorganic pigments, cadmium yellow,
Cadmium red, cadmium mercury red, chrome vermillion, lead cyanamide, antimony white, antimony red, titanium white, titanium yellow, lemon yellow, mars yellow, ocher, cobalt violet, manganese violet, ultramarine, berlin blue, cobalt blue, cerulean Blue, chrome green, emerald green, cobalt green, carbon black and the like.

The amount of the pigment used is generally 1 to the total of the above monomer and (meth) acrylonitrile.
It is preferably from 50 to 50% by weight, more preferably from 3 to 30% by weight. When the amount of the pigment used is less than 1% by weight, it is difficult to color the polymer fine particles in a dark color.
If it exceeds 0% by weight, the mechanical strength of the polymer fine particles will decrease.

As a specific method for producing the colored polymer fine particles of the present invention, the following method is suitable.

First, an appropriate amount of the above-mentioned monomer comprising a compound having an ethylenically unsaturated group, (meth) acrylonitrile and a pigment are mixed, and the pigment is mixed with the above-mentioned monomer and (meth)
Disperse uniformly in acrylonitrile. For mixing and dispersing the pigment, a ball mill, a bead mill, a sand mill, an attritor, a sand grinder, a nanomizer, or the like is used. In this case, if necessary, a known pigment dispersant such as Dispalon (trade name) manufactured by Kusumoto Kasei Co., Ltd. is used.

Next, a mixed solution of the monomer, (meth) acrylonitrile and pigment is suspended in an aqueous medium in the form of fine particles. Water is generally used as the aqueous medium. In this aqueous medium, an appropriate amount of a water-soluble suspension stabilizer is usually dissolved or an appropriate amount of a poorly water-soluble suspension stabilizer is dispersed and used.

Examples of the water-soluble suspension stabilizer include polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, gelatin, methyl cellulose, polymethacrylamide, polyethylene glycol, polyethylene oxide monostearate, sorbitan tetraoleate, and glycerin monooleate. And a water-soluble organic compound such as dodecylbenzenesulfonic acid.

Examples of the poorly water-soluble suspension stabilizer include barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, magnesium carbonate, calcium phosphate, magnesium phosphate colloid (a mixture of sodium diphosphate and sodium chloride), colloidal Insoluble inorganic compounds such as silica and aluminum oxide are used.

In order to suspend the mixture of the monomer, (meth) acrylonitrile and pigment in the form of fine particles in an aqueous medium, for example, the total amount of the monomer and (meth) acrylonitrile in the above-mentioned mixed solution is required. With respect to 100 parts by weight, 200 to 1000 parts by weight of the aqueous medium is mixed, and the mixture is stirred by a stirring blade. By changing the stirring speed of the stirring blade and the viscosity of the aqueous medium, it is possible to adjust the particle size and the particle size distribution of the suspended particles of the polymerizable monomer. The average particle size of the suspended particles is generally adjusted in the range of 0.1 to 300 μm.

In order to carry out suspension polymerization of the pigment-dispersed particulate monomer and (meth) acrylonitrile,
A radical polymerization initiator is added to the above suspension in advance, or it is added immediately before heating, and the radical polymerization initiator is decomposed by heating the radical polymerization initiator to polymerize the monomer and (meth) acrylonitrile. Let it.

As the radical polymerization initiator, an ordinary oil-soluble radical polymerization initiator comprising an azonitrile compound or an organic peroxide is used. The polymerization initiator consisting of azonitrile compounds, 2,2 ^'- azobisisobutyronitrile, ^2,2' - azobis-2,4 ^'- dimethyl valeronitrile, ^2,2' - azobis - methylbutyronitrile , 2,2 ^'- azobis - the like methyl f script nitrile.

Examples of the radical polymerization initiator composed of an organic peroxide include acetyl peroxide, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and peroxide. Diisopropyl carbonate, di-2-ethylhexyl peroxide, acetylcyclohexylsulfonyl peroxide, t-butyl perisobutyrate, t-butyl perivalate, t-butyl per-2-ethylhexanoate, di-t-butyl peroxide, T-butylcumyl peroxide, dicumyl peroxide and the like.

These radical polymerization initiators are generally used in the range of 0.5 to 15 parts by weight based on 100 parts by weight of the total amount of the monomer and (meth) acrylonitrile. When the amount of the initiator is less than 0.5 part by weight, the polymerization rate is significantly reduced,
No amount of initiator above 15 parts by weight is required. The polymerization temperature varies depending on the type of radical polymerization initiator used, but is generally about 40 to 150 ° C. The polymerization time is generally about 30 minutes to 10 hours.

In this way, colored polymer fine particles are produced. The colored polymer fine particles are separated by means such as filtration or centrifugal separation, washed with water or the like, and then dried by heating or reduced pressure to obtain colored polymer fine particles. Products. The colored polymer fine particles generally have an average particle size of about 0.1 to 300 μm, and the pigment is uniformly dispersed inside the polymer fine particles.

The colored polymer fine particles have excellent solvent resistance (the property that the pigment is not extracted by the organic solvent) and are usually used as they are, but if they are previously subjected to a surface treatment with a silane coupling agent, And the solvent resistance can be further improved.

The silane coupling agent used for this purpose includes γ-aminopropyltrimethoxysilane, N
-Β- (aminoethyl) -γ-aminopropyltrimethoxysilane, 3- [N-allyl-N- (2-aminoethyl)] aminopropyltrimethoxysilane, 3- [N-
Amino silane coupling such as allyl-N-glycidyl) aminopropyltriethoxysilane, 3- [N-allyl-N-methacryl) aminopropyltrimethoxysilane, 3- [N, N-diglycidyl) aminopropyltrimethoxysilane Agents are preferred.

Further, N, N-bis [3- (methyldimethoxysilyl) propyl] amine, N, N-bis [3-
(Trimethoxysilyl) propyl] amine, N, N-bis [3- (methyldimethoxysilyl) propyl] ethylenediamine, N, N-bis [3- (trimethoxysilyl) propyl] ethylenediamine, N-glycidyl-
Amide-based silane coupling agents such as N, N-bis [3- (methyldimethoxysilyl) propyl] amine and N-glycidyl-N, N-bis [3- (trimethoxysilyl) propyl] amine are also suitable.

In addition, vinyl silane coupling agents such as vinyltriethoxysilane, vinyl-tris (2-methoxyethoxy) silane, methacrylic silane coupling agents such as γ-methacryloxypropyltrimethoxysilane, and γ-glycide A glycidyl silane coupling agent such as xylpropyltrimethoxysilane and a mercapto silane coupling agent such as γ-mercaptopropyltrimethoxysilane are also used.

The colored polymer fine particles thus obtained are:
It is used for various purposes such as a labeling material, a carrier for a diagnostic reagent, a spacer for a liquid crystal display element, and is particularly suitable as a spacer for a liquid crystal display element.

To produce a liquid crystal display element using the above colored polymer fine particles as a spacer for a liquid crystal display element,
For example, the following method is adopted.

First, two transparent substrates with electrodes are prepared. Then, a sealing material made of light or a thermosetting adhesive in which peripheral spacers are dispersed is applied to the periphery of one of the transparent substrates in a frame shape except for a liquid crystal injection port. Further, as a spacer for a liquid crystal display element, an aqueous dispersion of the colored polymer fine particles whose particle size has been adjusted by classification is sprayed on the entire surface of the other transparent substrate and dried.

Thereafter, the one transparent substrate is superimposed on the other transparent substrate, and is opposed to each other with a certain gap therebetween through a sealing material and a spacer for a liquid crystal display element. To form cells.

Next, after injecting the liquid crystal into the cell from the liquid crystal injection port, the liquid crystal injection port is closed with a light or thermosetting liquid crystal injection port sealing agent, and the sealing agent is cured by light or heat. To seal the liquid crystal injection port to produce a liquid crystal display element.
In the obtained liquid crystal display element, the spacers for the liquid crystal display element are scattered on the entire surface of the substrate in contact with the liquid crystal in the cell gap.

As the liquid crystal, generally, a nematic liquid crystal,
In particular, a nematic liquid crystal having a positive dielectric anisotropy is used, but a cholesteric liquid crystal or a smectic liquid crystal can also be used.

[0048]

As described in the present invention, a monomer comprising 100 to 60% by weight of a compound having three or more ethylenically unsaturated groups and 0 to 40% by weight of a compound having two ethylenically unsaturated groups. 100 parts by weight of the body, 5 to 50 parts by weight of (meth) acrylonitrile, and the pigment are uniformly mixed,
When this is suspended in fine particles in an aqueous medium, (meth)
Acrylonitrile has a very strong electron withdrawing power due to the cyano group, so it has a high affinity for the surface of pigment particles,
It is believed that acrylonitrile collects near the surface of the pigment particles. As a result, it is presumed that the intermolecular force between the pigment particles is weakened, the aggregation of the pigment particles hardly occurs, and the pigment is uniformly dispersed in the fine particle droplets of the monomer.

When the suspension polymerization is carried out in a state where the pigment is uniformly dispersed in the fine particle droplets of the monomer, the (meth) acrylonitrile present near the surface of the pigment particles is copolymerized with the monomer. To form a copolymer and coat the surface of the pigment particles. In this way, the aggregation of the pigment particles is reliably prevented,
Colored polymer fine particles in which pigment particles are uniformly dispersed in polymer fine particles are obtained.

As described above, when the pigment particles are uniformly dispersed in the polymer fine particles, the mechanical strength is increased and the uniform and dark color is obtained as compared with the polymer fine particles dispersed in a state where the pigment particles are aggregated. It will be colored.

Moreover, since the monomer is composed of a compound having a specific ethylenically unsaturated group as described above, the polymer fine particles obtained by polymerization of this monomer have an appropriate crosslinked structure, It is presumed that the crosslinked structure and the molecular structure of the copolymer of (meth) acrylonitrile are combined to improve the mechanical strength and solvent resistance (the property that the pigment is not extracted by the organic solvent) of the colored polymer particles.

In particular, when the colored polymer fine particles as described above are used as a spacer for a liquid crystal display device, the spacer for a liquid crystal display device is excellent in mechanical strength and solvent resistance and is colored in a uniform and dark color. The visible light transmittance can be reduced to almost zero. As a result, when a display is performed using this liquid crystal display element, the spacer for the liquid crystal display element in the liquid crystal layer is not visually recognized as a white point in a dark part, and The display contrast can be prevented from lowering.

[0053]

EXAMPLES Examples and comparative examples of the present invention will be described below. Example 1 (1) Production of Colored Polymer Fine Particles 85.5 g of tetramethylolmethane triacrylate, 28.5 g of divinylbenzene, and acrylonitrile
And aniline black as a pigment was added thereto, and the pigment was uniformly dispersed over 48 hours using a bead mill.

To this pigment-dispersed monomer mixture, 2.0 g of benzoyl peroxide was uniformly mixed, and the mixture was added at a concentration of 3% by weight.
Was added to 850 g of an aqueous solution of polyvinyl alcohol, and the mixture was stirred well, and suspended in a fine particle having a particle size of about 3 to 10 μm with a homogenizer.

The suspension was transferred to a 2-liter separable flask equipped with a thermometer, a stirrer, and a reflux condenser.
The mixture was heated to 85 ° C. with stirring in a nitrogen atmosphere to carry out a polymerization reaction for 7 hours, and further heated at 90 ° C. for 3 hours to carry out a polymerization reaction.

Thereafter, the polymerization reaction solution was cooled, and the produced colored polymer fine particles were filtered, sufficiently washed with water and dried to obtain 145 g of colored polymer fine particles having a particle size of about 3 to 10 μm. The colored polymer particles were classified to obtain colored polymer fine particles having a desired particle size distribution.

(2) Performance Evaluation and Coloring State of Colored Polymer Fine Particles The color density of the above colored polymer fine particles was visually observed. In addition, when the surface and cut surface of the colored polymer fine particles were observed with a scanning electron microscope, it was confirmed that the pigment was uniformly dispersed inside the polymer fine particles.

Mechanical strength The colored polymer fine particles (average particle size 6.67 μm, standard deviation 0.35 μm) whose particle size was adjusted by classification using a micro compression tester (PCT-20, manufactured by Shimadzu Corporation). Was measured for mechanical strength. This mechanical strength is determined by measuring the 10% compressive deformation strength (K ₁₀ value) (kgf / mm ² ) of one fine particle sample.
It was evaluated based on the recovery rate (%) of the compressive deformation at the time of slow load.

Here, the strength (K ₁₀ value) of the 10% compressive deformation of the fine particle sample is K ₁₀ = ^{3/2 1/2} · ^FS · ^3/2 · R
Represented by ^-1/2, F is the compressive load (kgf), S is the displacement at 10% compressive deformation (mm), R is a particulate sample particle size (mm). As a result, K ₁₀ value ^{480 ± 20 (kgf / mm 2} ), the recovery rate 6
At 4.4%, the mechanical strength is excellent. -Solvent resistance 1 g of the colored polymer fine particles was added to 50 ml of an ethanol solvent and an acetone solvent, allowed to stand at 20 ° C for 7 days, filtered, and the filtrate was measured for the maximum absorption transmittance in the visible light region. As a result, the transmittance is 98.6 in the ethanol solvent.
%, And 97.5% in an acetone solvent, the pigment is hardly extracted (decolorized) by an organic solvent, and the solvent resistance is excellent.

(3) Production of Liquid Crystal Display Element As shown in the sectional view of FIG. 1, the transparent electrode (ITO thin film) 2
A sealing material 5 made of an epoxy acrylate-based photo-curable adhesive in which milled glass fibers (peripheral spacers) having a diameter of 6.48 μm are dispersed around one transparent glass substrate 1 on which Screen printing is performed in a frame shape except 6.

Further, on the entire surface of the other transparent glass substrate 1 on which the transparent electrode (ITO thin film) 2 is deposited, the colored polymer fine particles (average particle diameter of 6 (0.67 μm, standard deviation 0.35 μm) was sprayed to dry the dispersion to about 100 particles / mm ² and dried.

Thereafter, the one transparent glass substrate 1 is superimposed on the other transparent glass substrate 1 and is opposed with a certain gap therebetween via a sealing material 5 and a spacer A for a liquid crystal display element. Irradiates with ultraviolet light,
The sealing material 5 was light-cured to form cells. In addition, 3 is an alignment film and 4 is a polarizing plate.

After the nematic liquid crystal 8 is injected into the cell from the liquid crystal injection port 6, the liquid crystal injection port 6 is closed with a photo-curing type liquid crystal injection port sealing agent 7, which is irradiated with ultraviolet rays from a mercury lamp to seal the liquid crystal. The agent 7 was cured and the liquid crystal injection port 6 was sealed to produce a liquid crystal display element 9.

(4) Evaluation of Display Quality of Liquid Crystal Display Element Ten liquid crystal display elements were manufactured under the same conditions as above, and the gap between the substrates of each liquid crystal display element was measured. 05 μm.

When the display was performed in a negative type indicating a dark level in a state where no voltage was applied, the spacer in the liquid crystal layer was not visually recognized as a white point in the dark portion, and the display contrast of the liquid crystal display element was good. Table 1 summarizes the above results.

Examples 2 to 6 and Comparative Examples 1 to 5 In Example 1, a compound having three or more ethylenically unsaturated groups, a compound having two ethylenically unsaturated groups, (meth) acrylonitrile and pigment Was changed as shown in Tables 1 and 2. Other than that, it carried out similarly to Example 1. The results are summarized in Tables 1 and 2.

[0067]

[Table 1]

[0068]

[Table 2]

[0069]

As described above, the colored polymer fine particles of the present invention can be obtained from the compound 1 having three or more ethylenically unsaturated groups.
Polymer fine particles obtained by polymerizing 100 parts by weight of a monomer composed of 00 to 60% by weight and 0 to 40% by weight of a compound having two ethylenically unsaturated groups and 5 to 50 parts by weight of (meth) acrylonitrile The pigment is uniformly dispersed in the inside, whereby a deep color is obtained, and excellent mechanical strength and solvent resistance (a property that the pigment is not extracted by an organic solvent) are obtained.

The method for producing colored polymer fine particles of the present invention is characterized in that 100 to 60% by weight of a compound having three or more ethylenically unsaturated groups and 0 to 40% by weight of a compound having two ethylenically unsaturated groups. % Of a monomer consisting of 100% by weight, 5 to 50 parts by weight of (meth) acrylonitrile, and a pigment are uniformly mixed, and this is suspended in an aqueous medium in fine particles to carry out polymerization. Thereby, the pigment is uniformly dispersed and colored in a deep color, and colored polymer fine particles having excellent mechanical strength and solvent resistance (the property that the pigment is not extracted by the organic solvent) can be obtained.

Further, according to the method for producing colored polymer fine particles of the present invention, the production of the polymer fine particles and the uniform dispersion of the pigment inside the polymer fine particles are performed at once in one polymerization step. The process is simplified, and colored polymer fine particles can be manufactured at low cost.

Therefore, the colored polymer fine particles of the present invention can be suitably used for a labeling material, a carrier for a diagnostic reagent, a spacer for a liquid crystal display element, and the like. In particular, when used as a spacer for a liquid crystal display element, when the obtained liquid crystal display element is displayed, the spacer in the liquid crystal layer is not visually recognized as a white point in a dark portion, and a decrease in display contrast of the liquid crystal display element is prevented. There is an advantage that can be.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent glass substrate 2 Transparent electrode 3 Alignment film 4 Polarizing plate 5 Sealing material 6 Liquid crystal inlet 7 Liquid crystal inlet sealant 8 Liquid crystal 9 Liquid crystal display element A Liquid crystal display element spacer

Claims (4)

(57) [Claims] 1. A monomer 100 comprising 100 to 60% by weight of a compound having three or more ethylenically unsaturated groups and 0 to 40% by weight of a compound having two ethylenically unsaturated groups.
Pigment particles are uniformly dispersed in polymer particles obtained by polymerizing 5 parts by weight of (meth) acrylonitrile and 5 to 50 parts by weight of (meth) acrylonitrile. 2. A monomer 100 comprising 100 to 60% by weight of a compound having three or more ethylenically unsaturated groups and 0 to 40% by weight of a compound having two ethylenically unsaturated groups.
Parts by weight, 5 to 50 parts by weight of (meth) acrylonitrile, and a pigment, uniformly mixed, suspended in an aqueous medium to form fine particles, and polymerized. . 3. A spacer for a liquid crystal display device, comprising the colored polymer fine particles according to claim 1 or the colored polymer fine particles obtained by the production method according to claim 2. 4. A liquid crystal display device comprising two transparent substrates with electrodes arranged with electrodes facing each other, and liquid crystal sealed in the gap between the substrates, wherein the entire surface of the substrate in contact with the liquid crystal in the gap is covered. A liquid crystal display device, wherein spacers for the liquid crystal display device according to the above are interspersed.