JP4055869B2 - Method for producing black polyorganosiloxane fine particles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing black polyorganosiloxane fine particles, and more particularly to a method for efficiently producing monodisperse black polyorganosiloxane fine particles having a monodisperse particle size distribution, which are suitable as spacers for liquid crystal display devices and standard particles. Is.
[0002]
[Prior art]
In recent years, the development of liquid crystal display devices has been remarkable, not only those with small display units such as clocks, calculators, notebook computers, but also display devices for devices with large display units such as word processors, desktop computers, televisions, etc. It is used as.
[0003]
In this liquid crystal display device, in general, in a liquid crystal panel formed by facing two glass plates or plastic films on which electrode patterns are formed, a particle size as a spacer is used in order to keep the liquid crystal thickness constant. Very well aligned particles are arranged. In recent years, the demand for higher functionality has become more prominent with respect to the spacers for liquid crystal display devices as the liquid crystal panels have been increased in definition and size.
[0004]
Originally, liquid crystal molecules in a liquid crystal display device are aligned in a fixed direction by an alignment film such as polyimide, so that the entire liquid crystal panel exhibits a uniform display function. However, the spacer particles used for uniform display cause disturbance in the alignment as a foreign substance or cause light leakage in the aligned liquid crystal. Is given. That is, if the liquid crystal spacer is optically transparent, it will be difficult to leak the light from the spacer particles even if the light transmittance of the liquid crystal itself is minimized, and to make the liquid crystal screen black, that is, it is difficult to increase the contrast. Become.
[0005]
Therefore, various countermeasures have been taken so far to deal with such a problem, but it is not always satisfactory as described below.
[0006]
For example, a method has been proposed in which silica particles obtained by hydrolysis of a silicon alkoxide compound are heat-treated at a temperature of 250 ° C. or higher to obtain black particles (Japanese Patent Laid-Open No. 63-89408). However, the black particles obtained by this method are colored by decomposition carbonization of unreacted alkoxyl groups remaining inside the particles, but under the hydrolysis conditions described in the above publication, The amount of residual organic groups is not sufficient, and the amount of decomposed carbon is small, so that a sufficiently satisfactory light shielding degree cannot be obtained. Therefore, it is difficult to color the liquid crystal panel so that the light beam of the backlight is completely blocked. Further, as a problem different from the light shielding property, since the thermal expansion coefficient of silica itself is extremely smaller than that of the liquid crystal material, if the liquid crystal panel is exposed to a very low temperature such as −30 ° C. The spacer cannot follow the shrinkage and expansion of the liquid crystal cell due to the volume shrinkage and volume expansion of the material. On the low temperature side, a display defect called a low temperature bubble is generated, and on the high temperature side, the spacer is inside the cell. It is easy to cause an unfavorable situation such as floating, making it impossible to maintain a uniform cell gap, and similarly causing display defects. In addition, black silica particles obtained by firing are harder than resin color filters built inside color liquid crystal panels and transparent resin overcoat materials for flattening and protecting color filters, so they are embedded in these. As a result, the color filter and the overcoat material are easily damaged, and it is difficult to maintain a uniform cell gap.
[0007]
In addition, silica fine particles obtained by hydrolysis of a silicon alkoxide compound are brought into contact with, for example, hydrogen fluoride to introduce an organic group such as alcohol into the particles, and the particles are baked to carbonize the organic matter. A method for obtaining black silica has been proposed (Japanese Patent Laid-Open No. 3-279209). This method is excellent in that it can introduce carbon in an amount that can almost completely block the light beam of the backlight, but since the final black silica particles are hard, the compression deformation and thermal expansion are the same as described above. The coefficient is small, and as a result, low temperature bubbles and high temperature obstacles occur, and the spacers are sunk into the color filter and overcoat material.
[0008]
On the other hand, an organic polymer obtained from a hydrolyzable silicon compound having a radically polymerizable organic group in which at least one carbon atom is directly bonded to a silicon atom, and an organic-inorganic composite monodispersed fine particle having a siloxane bond are used as a crystal spacer. An example is disclosed (JP-A-8-81561). According to this method, the resulting particles have a smaller compressive modulus than silica fine particles, and phenomena such as low-temperature bubbles, high-temperature obstructions, or penetration into color filters, which are problems with silica fine particles, are greatly improved. There is an effect that. In this publication, it is shown that particles can be colored using a pigment or a dye in the synthesis process. However, according to this method, it is difficult to absorb a sufficient amount of pigment or dye inside the particles, and it is difficult to produce a spacer having excellent light shielding properties.
[0009]
[Problems to be solved by the invention]
Under such circumstances, the present invention is suitable as a spacer for a liquid crystal display device. The particle size distribution is monodispersed and has excellent light shielding properties, as well as low-temperature bubbles and high-temperature obstacles, or color filters and overcoats. It is an object of the present invention to provide a method for efficiently producing black polyorganosiloxane fine particles capable of suppressing obstacles such as penetration into a material.
[0010]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have determined that a silicon compound having a specific structure in which a non-hydrolyzable group and a hydrolyzable alkoxyl group are bonded to a silicon atom as a raw silicon compound The step of reacting this under specific conditions, the step of absorbing the carbon black fine particles into the generated polyorganosiloxane fine particles, the step of stabilizing the polyorganosiloxane fine particles that have absorbed the carbon black fine particles, and the stability of containing carbon black fine particles The present inventors have found that the purpose can be achieved by sequentially performing the step of drying the modified polyorganosiloxane fine particles, and based on this finding, the present invention has been completed.
[0011]
  That is, the present invention provides (A) the general formula
    R¹nSi (OR²)_4-n                            ... (I)
(Wherein R¹Is a non-hydrolyzable group having 1 to 20 carbon atoms, a (meth) acryloyloxy group or an epoxy group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, An aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, R²Is an alkyl group having 1 to 6 carbon atoms, n is an integer of 1,eachOR²They may be the same or different. )
A silicon compound having a specific gravity (23 ° C.) of 1 or less and an aqueous solution containing ammonia and / or an amine or a mixed solvent solution of water and an organic solvent. While maintaining the two-layer state, relational expression (II)
    Y ≦ 3 × 10^-4X²-0.0573X + 11.33 (II)
[However, X represents the reaction temperature (° C.) and is in the range of 0 to 55, and Y represents the pH of the lower layer during the reaction. ]
(B) After the silicon compound in the upper layer has substantially disappeared, the water-miscible solvent dispersion of carbon black fine particles is added to the resulting polyorganosiloxane fine particle dispersion. Then, the step of absorbing and introducing the carbon black fine particles into the polyorganosiloxane fine particles, (C) the polyorganosiloxane fine particles introduced with the carbon black fine particles at a pH exceeding the upper limit of Y in the above relational formula (II) The present invention provides a method for producing black polyorganosiloxane fine particles characterized by performing a step of reacting and stabilizing and a step (D) of drying the solidified polyorganosiloxane fine particles containing carbon black fine particles.
[0012]
  Main departureMysteriousBlack color obtained by the manufacturing methodPolyorganosiloxaneFine particlesThe liquid crystal displaySpaceretcAsCan be suitably used.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the method of the present invention, the general formula (I) is used as a raw material.
R¹nSi (OR²)_4-n                                 ... (I)
A silicon compound having a specific gravity (23 ° C.) of 1 or less is used.
[0014]
In the above general formula (I), R¹Is a non-hydrolyzable group having 1 to 20 carbon atoms, a (meth) acryloyloxy group or an epoxy group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, A 6-20 aryl group or a C7-20 aralkyl group is shown. Here, as a C1-C20 alkyl group, a C1-C10 thing is preferable, and this alkyl group may be linear, branched, or cyclic. Examples of this alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, and cyclopentyl. Group, cyclohexyl group and the like. As a C1-C20 alkyl group which has a (meth) acryloyloxy group or an epoxy group, the C1-C10 alkyl group which has the said substituent is preferable, and this alkyl group is linear, branched, Any of cyclic | annular form may be sufficient. Examples of the alkyl group having this substituent include γ-acryloyloxypropyl group, γ-methacryloyloxypropyl group, γ-glycidoxypropyl group, 3,4-epoxycyclohexyl group, and the like. The alkenyl group having 2 to 20 carbon atoms is preferably an alkenyl group having 2 to 10 carbon atoms, and the alkenyl group may be linear, branched or cyclic. Examples of the alkenyl group include vinyl group, allyl group, butenyl group, hexenyl group, octenyl group and the like. As a C6-C20 aryl group, a C6-C10 thing is preferable, for example, a phenyl group, a tolyl group, a xylyl group, a naphthyl group etc. are mentioned. As a C7-20 aralkyl group, a C7-10 thing is preferable, for example, a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group etc. are mentioned.
[0015]
  On the other hand, R²Is an alkyl group having 1 to 6 carbon atoms, which may be linear, branched or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, n- Examples thereof include a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a cyclopentyl group, and a cyclohexyl group. n is1'sIs an integer,eachOR²They may be the same or different.
[0016]
Among the silicon compounds represented by the general formula (I), in particular, the general formula (Ia)
CH_ThreeSi (OR²)_Three                               ... (Ia)
(Wherein R²Is the same as above, 3 OR²They may be the same or different. )
The silicon compound represented by these is preferable.
[0017]
Examples of the silicon compound represented by the general formula (Ia) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, methyltripentoxysilane, and methyltrihexoxysilane. , Methyltricyclohexoxysilane, methyldimethoxyethoxysilane, methyldiethoxymethoxysilane, and the like.
[0018]
In the present invention, one kind of silicon compound represented by the general formula (I) may be used as a raw material, or two or more kinds may be used in combination.
[0019]
Next, the method of the present invention will be described for each step.
[0020]
(A) Process
Step (A) is a step of hydrolyzing and condensing a silicon compound in which the specific gravity (23 ° C.) of the single substance or mixture represented by the general formula (I) is 1 or less to produce polyorganosiloxane fine particles of low condensate. It is a process of generating. In this step, the silicon compound represented by the general formula (I) and an aqueous solution containing ammonia and / or an amine or a mixed solvent solution of water and an organic solvent are substantially mixed without mixing. It is necessary to react at the interface while maintaining the state.
[0021]
The above ammonia and amine are catalysts for hydrolysis and condensation reaction of the silicon compound represented by the general formula (I). Here, preferred examples of the amine include monomethylamine, dimethylamine, monoethylamine, diethylamine, and ethylenediamine. Ammonia and amine may be used alone or in combination of two or more. However, ammonia is preferred because it is less toxic, easy to remove, and inexpensive. The ammonia or amine is used as an aqueous solution or a mixed solvent solution of water and an organic solvent. Here, the organic solvent is preferably water-miscible, for example, lower alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, dimethyl ketone and methyl ethyl ketone, ethers such as diethyl ether and dipropyl ether. And the like. The amount of ammonia or amine used depends on the reaction temperature, and is selected so that the pH of the lower aqueous layer before the start of the reaction is a value that satisfies the relationship (II) described below.
[0022]
In the present invention, it is necessary to gently stir the silicon compound and the ammonia or amine solution layer so that the two-layer state is maintained without substantially mixing. As a result, the silicon compound in the upper layer is hydrolyzed and transferred to the lower layer, where polyorganosiloxane fine particles are generated. These particles have the relationship (II)
Y ≦ 3 × 10^-FourX²-0.0573X + 11.33 (II)
[However, X represents the reaction temperature (° C.) and is in the range of 0 to 55, and Y represents the pH of the lower layer during the reaction. ]
By reacting at a temperature and pH satisfying the above conditions, the degree of condensation inside the particles is dispersed in a very low state. Therefore, in the carbon black introduction step of the next step, carbon black is absorbed inside the particles and becomes black particles. .
[0023]
That is, the pH of the lower layer during the reaction is 11.33 or less, the reaction temperature is in the range of 0 to 55 ° C., and the reaction temperature and the pH must satisfy the relational expression (II). .
[0024]
Thus, there is a specific pH and reaction temperature range in which carbon black can be introduced because of the amount of silanol produced by hydrolysis of the alkoxyl group of the silicon compound and the siloxane bond produced by condensation of the silanol groups. It is considered that the degree of progress of the hydrolysis polycondensation reaction inside the particles determined by the amount of (hereinafter sometimes referred to as the degree of condensation) is greatly related.
[0025]
(B) Process
Step (B) is a step of introducing carbon black into the low-condensation polyorganosiloxane fine particles produced in step (A). In this step, after the silicon compound in the upper layer substantially disappears, a water-miscible solvent dispersion of carbon black fine particles is added to the resulting polyorganosiloxane fine particle dispersion, and the carbon black is then added to the polyorganosiloxane fine particles. Fine particles are absorbed and introduced.
[0026]
In addition, when adding the dispersion liquid of carbon black microparticles | fine-particles, aggregation between polyorganosiloxane particles may arise. Therefore, it is desirable to add the dispersion liquid of carbon black fine particles after diluting the dispersion liquid of polyorganosiloxane fine particles with water or an aqueous solution of ammonia and / or amine. In this case, the dilution ratio is preferably about 2 to 100 times, particularly about 5 to 50 times. When the dilution ratio is less than 2 times, aggregation and particle coalescence are likely to occur, and the monodispersibility may be impaired. On the other hand, if the dilution ratio exceeds 100 times, the particle concentration becomes too small, and a large reaction vessel is required, and it takes much time for concentration, which is economically disadvantageous.
[0027]
Examples of the water-miscible solvent used in the dispersion of carbon black fine particles include lower alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, dimethyl ketone and methyl ethyl ketone, and ethers such as diethyl ether and dipropyl ether. And the like. The carbon black fine particle dispersion may contain a dispersant such as a surfactant. The maximum organic solvent concentration in the dispersion of the polyorganosiloxane fine particles after the carbon black fine particles are introduced must be less than 10% by weight because it is necessary to prevent the dissolution of the polyorganosiloxane fine particles. It is advantageous to adjust. The amount of carbon black fine particles added is not particularly limited, but is usually in the range of 2 to 1000 parts by weight, preferably 10 to 300 parts by weight per 100 parts by weight of the polyorganosiloxane fine particles.
[0028]
(C) Process
The step (C) is a step of stabilizing the low-condensation polyorganosiloxane fine particles into which the carbon black fine particles are introduced in the step (B) by increasing the degree of condensation inside the particles. By this stabilization step, aggregation and coalescence between particles are prevented, and an effect of confining carbon black inside the particles is exhibited.
[0029]
In this step, it is necessary to carry out the reaction at a pH exceeding the upper limit of Y in the relational formula (II) in order to increase the degree of condensation inside the particles. Accordingly, ammonia and / or amine is further added to the dispersion of the polyorganosiloxane fine particles into which carbon black has been introduced, and in some cases, heating to a temperature of 40 ° C. or higher is performed. In this stabilization step, when a method for increasing the degree of condensation is performed, hydrolyzable compounds dissolved in the solution may precipitate as fine particles. In this case, the precipitation / decantation method is used. Or it is preferable to remove by centrifugation etc.
[0030]
(D) Process
The step (D) is a step of drying the carbon black fine particle-containing stabilized polyorganosiloxane fine particles obtained by the stabilization treatment in the step (C). In this step, the polyorganosiloxane fine particles are first separated from the solvent and then dried, but the drying method is not particularly limited. Specifically, after replacing the solvent with a solvent having a small surface tension, the solvent and the particles are separated by stationary sedimentation or centrifugation, and the particles are preferably heated in an oven at 200 ° C. or less. A dry powder can be obtained.
[0031]
The carbon black fine particle-containing polyorganosiloxane fine particles thus dried may be subjected to a firing treatment as necessary in order to obtain a compressive strength necessary as a spacer for a liquid crystal device. This baking treatment is preferably performed at a temperature in the range of 300 to 800 ° C. in an inert atmosphere such as nitrogen or in a vacuum. If this temperature is less than 300 ° C, sufficient compressive strength may not be obtained, and if it exceeds 800 ° C, the particles may become too hard, which is not preferable. Moreover, there is no restriction | limiting in particular about a baking apparatus, Although an electric furnace, a rotary kiln, etc. can be used, it is advantageous to bake in the rotary kiln which can stir particle | grains.
[0032]
The particles obtained in this way may be subjected to a classification treatment as necessary to remove large particles. Although there is no restriction | limiting in particular as this classification processing method, The wet classification method which performs classification using the sedimentation speed changes with particle sizes is preferable.
[0033]
The black polyorganosiloxane fine particles containing carbon black inside obtained by the method of the present invention usually have an average particle size of 0.1 to 30 μm, preferably 0.5 to 15 μm, and a coefficient of variation in particle size distribution ( CV value) is usually 3.0% or less and is a monodisperse particle.
[0034]
The coefficient of variation (CV value) is obtained from the following equation.
[0035]
    CV value (%) = (standard deviation of particle size / average particle size) × 100
  The present inventionIn the manufacturing method ofBlackPolyorganosiloxaneFine particlesAs, Polyorganosiloxane fine particles containing carbon black, and the carbon black / Si weight ratio is in the range of 0.01 to 5, preferably 0.03 to 2.Can get things. When the carbon black / Si weight ratio is less than 0.01, the light shielding performance is poor, and when it exceeds 5, the breaking strength is lowered. The specific resistance is 1.0 × 10¹⁰Ω / cm or more, average particle size of 0.1 to 30 μm, CV value is 3.0% or less, and Y value is 10% or less, preferably 5% or less in an XYZ system of a color defined by JIS Z8701.
[0036]
As described above, the specific resistance is very large even though the conductive agent carbon black is considerably contained. This indicates that the carbon black is confined inside the particle, and therefore, the carbon black has a characteristic that it is extremely difficult to drop off from the particle.
[0037]
  The present inventionObtained by the manufacturing methodBlackPolyorganosiloxaneUsing fine particles as spacersLiquidThe crystal display device has features such as (1) excellent light shielding properties, (2) low temperature bubbles and high temperature obstacles are suppressed, and (3) obstacles such as penetration into color filters and overcoat materials are suppressed. is doing.
[0038]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
[0039]
Example 1
(1) (A) Process
A 2 liter separable flask equipped with a stirring blade is set in a thermostatic bath, and 1800 ml of ion exchange water and 1.5 ml of 1N ammonia water are put therein, and the solution is stirred while keeping the thermostatic bath at 20 ° C. Stir and mix. Next, 180 g of methyltrimethoxysilane is poured into the upper layer of the ammonia water while gently stirring at a rotation speed of the stirring blade of 20 rpm, and 2 g of methyltrimethoxysilane and dilute ammonia water are poured into the reaction vessel wall. While maintaining the layer state, the hydrolysis reaction was started. At this time, the pH of the aqueous ammonia was 10.18, and the relationship between the reaction temperature and pH satisfied the formula (II).
[0040]
After 80 minutes from the start of the reaction, the lower layer aqueous solution began to become cloudy, and the upper layer methyltrimethoxysilane decreased with the passage of time, and stirring was continued until all the methyltrimethoxysilane disappeared. When a part of the lower layer aqueous solution was taken out and placed on a slide glass and observed with an optical microscope, monodispersed spherical polymethylsiloxane fine particles were produced. Moreover, it was 8.73 when pH in that case was measured.
[0041]
(2) Steps (B) to (D)
A 10-liter plastic container equipped with a stirring blade is set in a thermostatic bath, and 100 g of the particle dispersion obtained in (1) above is added, and 5000 ml of ion-exchanged water is added while maintaining the liquid temperature at 20 ° C. Thus, a liquid in which the particle dispersion was diluted 50 times was obtained. The pH of the diluted solution was measured and found to be 7.81. Next, 20 g of a carbon black isopropanol dispersion (manufactured by Mikuni Dye Co., Ltd., MHI Black # 217) with a concentration of 30% by weight was added dropwise over 5 minutes with gentle stirring, and carbon black was absorbed inside the particles. The pH at that time was 5.68.
[0042]
After stirring for 30 minutes, 600 ml of a 5 wt% aqueous solution of polyvinyl alcohol was added thereto, and then 16 ml of 25 wt% aqueous ammonia was added to stabilize particles formed by absorbing carbon black. Under the present circumstances, pH during reaction was 10.43 and exceeded the upper limit of Y of a formula (II). Thereafter, after aging at room temperature for 12 hours, carbon black-containing particles were precipitated from the particle dispersion using a centrifuge. After discarding the supernatant in which the carbon black that was not absorbed by the particles was suspended, the particles were washed by repeating the operation of adding methanol to re-disperse, sedimenting again with a centrifuge, and discarding the supernatant. .
[0043]
Next, black particles were obtained by removing methanol and drying in an oven at 150 ° C. Moreover, as a result of measuring the specific resistance of the black particles, 0.91 × 10¹¹Since it was Ω / cm and was an insulator, it was found that carbon black was absorbed inside the particles.
[0044]
Moreover, when Y value was measured using the color analyzer 307 by Hitachi, Ltd., it was 1.8%. And it was 1.38 when specific gravity measurement was performed using helium gas using Shimadzu Corporation micromeritics Accupic 1330. Since the specific gravity of the carbon black non-introduced particles was 1.34, the carbon black / Si weight ratio was 0.2.
[0045]
(3) Firing process
The carbon black-containing black particles obtained in the above (2) were baked at 620 ° C. for 4 hours in a nitrogen atmosphere. The obtained particles were measured for fracture strength on a steel plate using a micro compression tester MCTE-200 manufactured by Shimadzu Corporation. The result was 76 kgf / mm.²Met. The fired particles did not show fading and maintained blackness. The Y value was measured and found to be 1.7%.
[0046]
(4) Classification process
Large particles were removed by wet-classifying the black particles obtained in (3) above using the difference in sedimentation speed due to the difference in particle size. The black particles were monodispersed with an average particle size of 3.66 μm and a CV value of 1.80% as a result of particle size measurement with a scanning electron microscope (SEM).
[0047]
(5) Particle reliability test
1 g of the black particles obtained in (4) above were mixed in 2 g of nematic liquid crystal (Merck, ZLI-5150) placed in a 5 ml glass container, and the inside of the container was replaced with nitrogen gas and sealed. Thereafter, this container was held at 90 ° C. for 72 hours, and then the liquid crystal was taken out and the specific resistance was measured. As a result, the specific resistance of the blank liquid crystal containing no black particles is 8.8 × 10.^TenΩ / cm vs 1.0 × 10¹¹It was Ω / cm, and there was no leaching of carbon black and no elution of impurities such as ions.
[0048]
Example 2
In Example 1- (1), polymethylsiloxane particles were obtained in the same manner as in Example 1- (1) except that the amount of 1N ammonia water added was changed to 0.9 ml. At this time, the pH of the ammonia water before the start of the reaction was 10.12, and the reaction temperature and pH satisfied the relational expression (II). Moreover, pH after reaction was 8.24.
[0049]
Next, in the same manner as in Example 1- (2), the carbon black introduction step [(B) step], the stabilization step [(C) step] and the drying step [(D) step] are sequentially performed. Thus, black polymethylsiloxane fine particles in which carbon black was introduced inside the particles were obtained. The Y value was measured and found to be 0.9%.
[0050]
Example 3
In Example 1- (1), polymethylsiloxane particles were obtained in the same manner as in Example 1- (1) except that the amount of 1N ammonia water added was 2.0 ml. At this time, the pH of the ammonia water before the start of the reaction was 10.28, and the reaction temperature and pH satisfied the relational expression (II). Moreover, pH after reaction was 8.84.
[0051]
Next, in the same manner as in Example 1- (2), the carbon black introduction step [(B) step], the stabilization step [(C) step] and the drying step [(D) step] are sequentially performed. Thus, black polymethylsiloxane fine particles in which carbon black was introduced inside the particles were obtained. The Y value was measured and found to be 2.8%.
[0052]
Example 4
In Example 1- (1), a polymethylsiloxane particle was obtained by performing the same operation as in Example 1- (1) except that the thermostat was maintained at 5 ° C. At this time, the pH of the ammonia water before the start of the reaction was 11.00, and the reaction temperature and pH satisfied the relational expression (II). Moreover, pH after reaction was 8.55.
[0053]
Next, in the same manner as in Example 1- (2), the carbon black introduction step [(B) step], the stabilization step [(C) step] and the drying step [(D) step] are sequentially performed. Thus, black polymethylsiloxane fine particles in which carbon black was introduced inside the particles were obtained. The Y value was measured and found to be 1.6%.
[0054]
Example 5
In Example 1- (1), the same operation as in Example 1- (1) was performed except that the thermostat was kept at 30 ° C. and the amount of 1N ammonia water added was 0.9 ml. Polymethylsiloxane particles were obtained. At this time, the pH of the ammonia water before the start of the reaction was 9.75, and the reaction temperature and pH satisfied the relational expression (II). Moreover, pH after reaction was 8.06.
[0055]
Next, in the same manner as in Example 1- (2), the carbon black introduction step [(B) step], the stabilization step [(C) step] and the drying step [(D) step] are sequentially performed. Thus, black polymethylsiloxane fine particles in which carbon black was introduced inside the particles were obtained. The Y value was measured and found to be 2.2%.
[0056]
Example 6
In Example 1- (1), the same operation as in Example 1- (1) was performed except that the thermostat was maintained at 25 ° C. and the amount of 1N ammonia water added was 0.9 ml. Polymethylsiloxane particles were obtained. At this time, the pH of the ammonia water before the start of the reaction was 9.96, and the reaction temperature and pH satisfied the relational expression (II). Moreover, pH after reaction was 7.94.
[0057]
Next, in the same manner as in Example 1- (2), the carbon black introduction step [(B) step], the stabilization step [(C) step] and the drying step [(D) step] are sequentially performed. Thus, black polymethylsiloxane fine particles in which carbon black was introduced inside the particles were obtained. The Y value was measured and found to be 1.9%.
[0058]
Example 7
In Example 1- (1), except that ion-exchanged water was 1500 ml, 1N ammonia water was 0.3 ml, and 240 g of vinyltrimethoxysilane was used instead of the raw material methyltrimethoxysilane. The same operation as in 1- (1) was performed to obtain polyvinylsiloxane fine particles. At this time, the pH of the ammonia water before the start of the reaction was 9.92, and the reaction temperature and pH satisfied the relational expression (II).
[0059]
Next, in the same manner as in Example 1- (2), the carbon black introduction step [(B) step], the stabilization step [(C) step] and the drying step [(D) step] are sequentially performed. Thus, black polyvinylsiloxane fine particles in which carbon black was introduced inside the particles were obtained. The Y value was measured and found to be 1.0%.
[0060]
Comparative Example 1
In Example 1- (1), polymethylsiloxane fine particles were obtained in the same manner as in Example 1- (1) except that the amount of 1N ammonia water added was changed to 3 ml. At this time, the pH of the ammonia water before the start of the reaction was 10.33, and the reaction temperature and pH did not satisfy the relational expression (II). Therefore, in the carbon black introduction process, almost no carbon black entered the particles. It was. Moreover, pH after reaction was 8.81.
[0061]
Comparative Example 2
In Example 1- (1), polymethylsiloxane fine particles were obtained in the same manner as in Example 1- (1), except that the amount of 1N ammonia water added was changed to 5 ml. At this time, the pH of the ammonia water before the start of the reaction was 10.54, and the reaction temperature and pH did not satisfy the relational expression (II). Therefore, in the carbon black introduction step, almost no carbon black entered the particles. It was. Moreover, pH after reaction was 8.98.
[0062]
Comparative Example 3
In Example 1- (1), except that the reaction temperature was changed to 38 ° C., the same operation as in Example 1- (1) was performed to obtain polymethylsiloxane fine particles. At this time, the pH of the ammonia water before the start of the reaction was 9.63, and the reaction temperature and pH did not satisfy the relational expression (II). Therefore, in the carbon black introduction step, almost no carbon black entered the particles. It was. Moreover, pH after reaction was 8.30.
[0063]
Comparative Example 4
Except having changed reaction temperature into 30 degreeC in Example 1- (1), operation similar to Example 1- (1) was performed and the polymethylsiloxane fine particle was obtained. At this time, the pH of the ammonia water before the start of the reaction was 9.90, and the reaction temperature and pH did not satisfy the relational expression (II). Therefore, in the carbon black introduction process, almost no carbon black entered the particles. It was. Moreover, pH after reaction was 8.07.
[0064]
【The invention's effect】
According to the present invention, the particle size distribution suitable as a spacer for a liquid crystal display device is monodispersed and has excellent light shielding properties, and also has problems such as low-temperature bubbles and high-temperature obstacles, or penetration into color filters and overcoat materials. The black polyorganosiloxane fine particles that can be suppressed can be efficiently produced.

Claims (5)

(A) General formula R ¹ nSi (OR ² ) _4-n (I)
(In the formula, R ¹ is a non-hydrolyzable group having 1 to 20 carbon atoms, a (meth) acryloyloxy group or an epoxy group having 1 to 20 carbon atoms, or 2 to 20 carbon atoms). An alkenyl group, an aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, R ² is an alkyl group having 1 to 6 carbon atoms, n is an integer of 1 , and each OR ² is the same It may or may not be.)
A silicon compound having a specific gravity (23 ° C.) of 1 or less and an aqueous solution containing ammonia and / or an amine or a mixed solvent solution of water and an organic solvent. While maintaining the two-layer state, relational expression (II)
Y ≦ 3 × 10 ⁻⁴ X ² −0.0573X + 11.33 (II)
[However, X represents the reaction temperature (° C.) and is in the range of 0 to 55, and Y represents the pH of the lower layer during the reaction. ]
(B) After the silicon compound in the upper layer has substantially disappeared, the water-miscible solvent dispersion of carbon black fine particles is added to the resulting polyorganosiloxane fine particle dispersion. Then, the step of absorbing and introducing the carbon black fine particles into the polyorganosiloxane fine particles, (C) the polyorganosiloxane fine particles introduced with the carbon black fine particles at a pH exceeding the upper limit of Y in the above relational formula (II) A method for producing black polyorganosiloxane fine particles, comprising: reacting and stabilizing; and (D) drying the carbon black fine particle-containing stabilized polyorganosiloxane fine particles. The silicon compound represented by the general formula (I) is represented by the general formula (Ia)
CH ₃ Si (OR ² ) ₃ (Ia)
(In the formula, R ² represents an alkyl group having 1 to 6 carbon atoms, and three OR ² may be the same or different.)
The production method according to claim 1, wherein the compound is represented by the formula:   In step (C), ammonia and / or amine is further added to the dispersion of the polyorganosiloxane fine particles that have absorbed the carbon black fine particles, and optionally heated to a temperature of 40 ° C. or higher to absorb the carbon black fine particles. The manufacturing method of Claim 1 or 2 which stabilizes microparticles | fine-particles. In the step (D), after the carbon black fine particle-containing stabilized polyorganosiloxane fine particles are dried, they are further fired at a temperature in the range of 300 to 800 ° C in an inert atmosphere or in a vacuum. Or the manufacturing method of 3 .   The resulting black polyorganosiloxane fine particles are polyorganosiloxane fine particles containing carbon black and have a carbon black / Si weight ratio of 0.01 to 5 and a specific resistance of 1.0 × 10. ¹⁰ Ω / cm or more, average particle size of 0.1 to 30 μm, coefficient of variation (CV value) of particle size distribution is 3.0% or less, and Y value is 10% or less in an XYZ system of colors defined by JIS Z8701. The manufacturing method in any one of Claims 1-4.