JP4397981B2 - Method for producing polyorganosiloxane fine particles - Google Patents

Description

【００６２】
焼成後に得られたポリオルガノシロキサン微粒子は、表１に示すような破壊強度を有し、液晶表示装置用スペーサとして特に好適であることが明らかとなった。
【００６３】
【発明の効果】
本発明の方法によれば、比較的大きな粒径（４〜１０μｍ程度）で、かつ粒径分布が単分散のポリオルガノシロキサン微粒子を、所望の粒径のものが得られるように、効率よく製造することができる。
本発明の方法で得られたポリオルガノシロキサン微粒子は、液晶表示装置用スペーサや標準粒子などとして好適である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a method for producing polyorganosiloxane fine particles. More specifically, the present invention relates to a polydisperse having a particle size suitable for spacers for liquid crystal display devices and standard particles (about 4 to 10 μm) and having a monodispersed particle size distribution. The present invention relates to a method for efficiently producing organosiloxane fine particles so as to obtain particles having a desired particle diameter.
[0002]
[Prior art]
Conventionally, silica particles having a monodispersed particle size distribution (hereinafter sometimes simply referred to as monodispersed silica particles) are known to be useful as various fillers, ceramic raw materials, etc. The use as a spacer of a liquid crystal display device has attracted attention and has started to be used.
[0003]
Conventionally, glass fiber chips or fine particles of synthetic resin have been used for spacers of liquid crystal display devices. However, the glass fiber chip has excellent fiber diameter accuracy, but its length varies widely, and if it is too long, there is a risk that the image quality will be deteriorated by visual inspection, and the end of the glass fiber chip is sharp. There is a risk of damaging the formed alignment film, protective film, color filter, or electric element. In addition, since the fine particles of the synthetic resin are inferior in particle size accuracy, the performance required as a spacer for a liquid crystal display device may not be satisfied. Therefore, when a higher degree of gap accuracy is required, the particle size accuracy is good and spherical, and there is a risk of damaging an electrical element such as an alignment film, a protective film, a color filter or an ITO conductive film formed on the substrate. Those without are required.
[0004]
In order to satisfy these requirements, silica particles obtained by hydrolyzing and polycondensing silicon alkoxide have been proposed. These silica particles are
(1) High purity and little influence on liquid crystal by elution components
(2) Good particle size accuracy,
CV (%) = [standard deviation of fine particle diameter (μm)]
/ [Average particle diameter (μm)] × 100
The CV value (coefficient of variation) obtained by
(3) Since almost perfect spheres can be obtained, there is no risk of damaging an alignment film, a protective film, a color filter, or an electric element such as an ITO conductive film formed on the substrate.
It has the advantages such as.
[0005]
Since silica particles obtained by hydrolysis and polycondensation of silicon alkoxide have the advantages as described above, many production methods have been proposed so far.
For example, as a method for producing spherical polymethylsilsesquioxane, methyltrialkoxysilane or a partially hydrolyzed condensate thereof and an aqueous solution containing ammonia or amine or a mixed solvent solution of water and an organic solvent are substantially mixed. There has been proposed a method of reacting while maintaining the two-layer state (Japanese Patent Publication No. 4-70335).
[0006]
However, in this method, the particle size of the polymethylsilsesquioxane particles to be generated is controlled by the concentration of ammonia and amine in the lower layer at the time of charging, but the generation of core particles is uncertain, so the generated particles There is a problem that the number of nuclei is likely to vary, and even if the reaction is carried out under the same reaction conditions, the diameter of the particles finally obtained does not become the target particle diameter. For example, when manufacturing 10 times under the same conditions for the purpose of obtaining particles having an average particle diameter of 5 μm, a variation of about 40% (about ± 2.0 μm) occurs with respect to the target particle diameter.
Thus, if a desired particle diameter cannot be obtained, there arises a problem that it is difficult to use for a spacer for a liquid crystal display device or the like that strictly requires the particle diameter accuracy.
[0007]
Accordingly, the present inventors have repeated research on a method for efficiently producing polyorganosiloxane fine particles having a monodispersed particle size distribution so that particles having a desired particle size can be obtained. A method for hydrolyzing and condensing alkoxysilane having a non-hydrolyzable group in the presence of an agent was found and a patent was filed (Japanese Patent Application No. 9-234859).
[0008]
According to this method, when the production of the polyorganosiloxane fine particles is repeated, the variation with respect to the target particle size is 10% or less, which is smaller than the method described in the above Japanese Patent Publication No. 4-70335. The accuracy of control is greatly improved, which is a preferable method. By the way, recently, it has been demanded to obtain polyorganosiloxane fine particles having a particle size (about 4 to 10 μm) suitable for use as a spacer for liquid crystal display devices with high particle size accuracy.
[0009]
[Problems to be solved by the invention]
Under such circumstances, the present invention provides polyorganosiloxane fine particles having a particle size (about 4 to 10 μm) particularly suitable as a spacer for a liquid crystal display device and having a monodispersed particle size distribution. The present invention provides a method for efficiently producing a product having a particle size.
[0010]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have found that a silicon compound in which a non-hydrolyzable group and a hydrolyzable alkoxyl group are bonded to a silicon atom in an aqueous solution of ammonia or amine. When hydrolyzing and condensing, a hydrolysis reaction is performed at a specific initial pH and until the degree of pH decrease reaches a certain value, seed particles are produced, then diluted, and then the diluted solution is mixed with the above-mentioned The inventors have found that the purpose can be achieved by performing the operation of adding seeds and growing seed particles one or more times, and have completed the present invention based on this finding.
[0011]
That is, the present invention relates to the general formula (I)
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, R²Represents an alkyl group having 1 to 6 carbon atoms, n represents an integer of 1 to 3, and R¹Each R¹May be the same or different, OR²If there is more than one, each OR²They may be the same or different. )
In producing polyorganosiloxane fine particles by hydrolyzing and condensing a silicon compound represented by
(A) The pH of the reaction solution at the start of the reaction is adjusted to 9.7 to 11.7, and the amount of silicon compound is set and added so that the pH is reduced by 0.7 to 1.5. And a seed particle liquid preparation step for producing seed particles in the range of pH 8.2 to 11.0 at the end of the reaction, and diluting the reaction liquid to become seed particle liquid, and
(B) A seed particle growth step in which the seed particle liquid obtained in step (A) is added with the silicon compound represented by the general formula (I) to grow seed particles one or more times.
The present invention provides a method for producing polyorganosiloxane fine particles characterized in that
[0012]
Further, in a preferred embodiment for carrying out the present invention, in the above production method, the final particle diameter R (μm) after growth is expressed by the relational expression (II)
R = r [K (M / m) +1]^1/3                          ... (II)
[Where r is the seed particle size (μm), K is the dilution ratio of the seed particles, and M and m are the concentrations (% by weight) of the silicon compound used in the steps (B) and (A), respectively. ]
Is to control according to.
[0013]
A particularly preferred embodiment is that, in the step (A), when generating seed particles, a nonionic surfactant having an HLB value of preferably 8 to 20 is added, and the final particle diameter R (μm) after growth is Relational expression (III)
R = C [{K (M / m) +1} / x]^1/3                  ... (III)
[Wherein x is the nonionic surfactant concentration (wt%) at the time of seed particle generation, C is a constant determined by the reaction conditions at the time of seed particle generation, and K, M and m are the relational expressions (II) As defined. ]
Is to control according to.
[0014]
Another preferred embodiment for carrying out the present invention is to subject the particles obtained after hydrolysis and condensation to a firing treatment.
[0015]
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)
The silicon compound represented by these is used.
[0016]
In the above general formula (I), R¹Is an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms having a (meth) acryloyloxy group or an epoxy group, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a carbon number 7 to 20 aralkyl groups are 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.
[0017]
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 is an integer of 1 to 3, and R¹Each R¹May be the same or different, and OR²If there is more than one, each OR²They may be the same or different.
[0018]
Examples of the silicon compound represented by the general formula (I) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethyl. Ethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyl Examples thereof include oxypropyltrimethoxysilane, dimethyldimethoxysilane, and methylphenyldimethoxysilane. Of these, methyltrimethoxysilane and vinyltrimethoxysilane are particularly preferred.
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]
The method of the present invention comprises (A) a seed particle liquid preparation step and (B) a seed particle growth step.
[0020]
(A) Seed particle solution preparation process
In this step (A), the pH of the reaction solution at the start of the reaction is adjusted to 9.7 to 11.7, and expressed by the general formula (I) so that the pH is reduced by 0.7 to 1.5. The amount of the silicon compound to be set is set to perform a hydrolysis reaction, and seed particles are generated in a pH range of 8.2 to 11.0 after completion of the reaction. Thereby, the condensation degree of the produced seed particles automatically becomes a desired preferable range. The seed particle growth reaction in the next step [(B) step] proceeds with the absorption of the hydrolysis condensate of the raw material, so if the degree of condensation of the seed particles is too high, Absorption is less likely to occur, and the hydrolysis condensate precipitates in the reaction system, causing generation of particles other than seed particles. Furthermore, when the degree of condensation increases, the surface of the particles becomes more hydrophobic, which causes poor dispersion of the particles. On the other hand, when the degree of condensation is too low, the particles are coalesced during the growth of the seed particles, and the particle size distribution is deteriorated. Next, after generating seed particles in this way, the reaction liquid is diluted with an aqueous medium so that the dilution rate is about 2 to 200 times to prepare a seed particle liquid. At this time, it is preferable to dilute without adding a new catalyst component in order to prevent generation of new core particles in the growth reaction described below. In addition, all the said pH is a value in 30 degreeC.
[0021]
In this step, in order to hydrolyze the silicon compound represented by the general formula (I) to produce seed particles, the silicon compound is usually hydrolyzed in the presence of ammonia and / or an amine aqueous solution. A method of condensation is used. Ammonia and amine used at this time are catalysts for hydrolysis and condensation reaction of the silicon compound. 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.
[0022]
Examples of the aqueous ammonia and / or amine solution include a solution in which ammonia and / or an amine is dissolved in water or a mixed solvent of water and a water-miscible organic solvent. Here, examples of the water-miscible organic solvent include lower alcohols such as methanol, ethanol, propanol and butanol, and ketones such as acetone. These may be mixed with water alone or in combination of two or more with water.
[0023]
In the present invention, the amount of ammonia or amine used is such that the pH (initial pH) of the aqueous layer at the start of the reaction is in the range of 9.7 to 11.7, preferably 9.7 to 11.2. Selected. If the initial pH deviates from the above range, the object of the present invention cannot be sufficiently achieved.
There is no restriction | limiting in particular as a reaction format in this (A) process, Although both mixing homogeneous system reaction and two-layer system reaction can be used, in obtaining the particle | grains with a small CV value and the outstanding particle size precision, A two-layer system is more advantageous.
[0024]
In the mixed homogeneous reaction, the silicon compound represented by the general formula (I) and the ammonia and / or amine-containing aqueous solution are mixed and stirred to obtain an initial pH of 9.7 to 11.7, preferably 9.7 to 11.2, and subjected to a hydrolysis reaction until the pH is reduced by 0.7 to 1.5, and the seed at a pH of 8.2 to 11.0 at the end of the reaction Generate particles. The reaction temperature at this time depends on the type of silicon compound as a raw material, but is generally selected in the range of 0 to 50 ° C.
[0025]
On the other hand, in the two-layer reaction, a raw material silicon compound having a specific gravity (23 ° C.) of 1 or less represented by the general formula (I) is 1 or less.
First, while maintaining a two-layer state without substantially mixing this silicon compound with an ammonia and / or amine-containing aqueous solution, the initial pH is 9.7 to 11.7, preferably 9.7 to 11.2. And a hydrolysis reaction at the interface until the pH drops by 0.7 to 1.5.
[0026]
In this reaction, 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 seed particles are generated in the range where the pH at the end of the reaction is 8.2 to 11.0. The reaction temperature at this time depends on the type of silicon compound as a raw material, but is generally selected in the range of 0 to 50 ° C.
[0027]
In this way, after generating seed particles by a reaction of mixed homogeneous system or two-layer system, the reaction solution is aqueous so that the dilution ratio is preferably 2 to 200 times, more preferably 5 to 100 times. Dilute with medium to prepare seed particle solution. At this time, as the aqueous medium used for dilution, water or a mixed solvent of water and a water-miscible organic solvent is used. In the hydrolysis reaction, it is preferable to use the same one as that used as the reaction medium. .
[0028]
In the present invention, in the step (A), when the silicon compound represented by the general formula (I) is hydrolyzed and condensed to produce seed particles, ammonia containing a nonionic surfactant and It is preferable to hydrolyze and condense in the presence of an aqueous amine solution.
[0029]
By including the nonionic surfactant in this way, the particle size r (μm) of the seed particle is expressed by the relational expression (IV)
r = C · x^-1/3                                         ... (IV)
It becomes possible to control by. Here, x is the concentration (% by weight) of the nonionic surfactant in the aqueous solution. C is a constant, and is determined by the type of nonionic surfactant used (for example, HLB value) and reaction conditions (for example, concentration and pH of ammonia and / or amine in the aqueous solution). .
[0030]
This C is obtained in advance by a preliminary experiment, and in the actual production of seed particles, based on the relational expression (IV), from the desired seed particle diameter and C value, the value of x (in the aqueous solution) What is necessary is just to determine a nonionic surfactant density | concentration. Although this x depends on the type of nonionic surfactant, it is generally 10^-Five~ 5x10^-2It is selected in the range of% by weight. If this surfactant concentration deviates from the above range, the effects of the present invention may not be sufficiently exhibited.
[0031]
In the present invention, as the nonionic surfactant, those having an HLB value in the range of 8 to 20 are preferably used. This HLB is an index representing the balance between hydrophilicity and lipophilicity, and the smaller the value, the higher the lipophilicity. If the HLB value deviates from the above range, the effects of the present invention may not be sufficiently exhibited. In order to better exhibit the effects of the present invention, those having an HLB value in the range of 10 to 17 are particularly preferable.
[0032]
The nonionic surfactant is not particularly limited as long as it has an HLB value in the above range, and examples thereof include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sterol ether, polyoxyethylene Ethylene lanolin derivatives, ethylene oxide derivatives of alkylphenol formalin condensates, polyoxyethylene polyoxypropylene block polymers, ether type nonionic surfactants such as polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, polyoxyethylene Ether ester type nonionic properties such as castor oil and hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester Surfactants, polyethylene glycol fatty acid esters, polyglycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, ester type nonionic surfactants such as sucrose fatty acid esters, polyoxyethylene fatty acid amides, polyoxyethylene alkylamines, alkyls Examples thereof include nitrogen-containing nonionic surfactants such as amine oxides. Among these, ether type is preferable, and polyoxyethylene alkylphenyl ether is particularly preferable. These nonionic surfactants may be used alone or in combination of two or more.
[0033]
(B) Seed particle growth process
In the step (B), the silicon compound represented by the general formula (I) is added to the seed particle liquid obtained in the step (A) and the seed particle is grown once or more. It is.
There is no restriction | limiting in particular as the reaction format in this process, Both a mixed homogeneous reaction and a two-layer system reaction can be used similarly to the said (A) process.
In the mixed homogeneous reaction, the silicon compound represented by the general formula (I) is added to the seed particle liquid obtained in the step (A), and the mixture is reacted in a mixed homogeneous system while stirring to obtain seed particles. Grow. The reaction temperature at this time depends on the type of silicon compound as a raw material, but is generally selected in the range of 0 to 50 ° C. The reaction can be stopped by adding ammonia and / or an amine to the reaction system.
[0034]
The appropriate timing of adding ammonia or amine depends on the type of raw material, reaction temperature, pH, etc., so in a preliminary experiment, the relationship between the type of raw material, reaction temperature, pH, etc. and the appropriate timing of addition was examined in advance. It is desirable to add ammonia and amine at an appropriate time using this.
On the other hand, in the two-layer reaction, the specific gravity (23 ° C.) of the single compound or mixture represented by the general formula (I) is 1 as the raw silicon compound, as in the two-layer reaction in the step (A). The following are used.
[0035]
In this two-layer reaction, it is necessary to gently stir the silicon compound and the seed particle liquid so as to maintain the two-layer state without substantially mixing them. As a result, the silicon compound in the upper layer is hydrolyzed and transferred to the lower layer, where seed particles grow. The reaction temperature at this time depends on the type of silicon compound as a raw material, but is generally selected in the range of 0 to 50 ° C.
In this two-layer reaction, it is advantageous to stop the reaction by adding ammonia and / or amine to the reaction system after the upper layer disappears.
[0036]
In such a two-layer reaction in the method of the present invention, the particle diameter R (μm) of the finally obtained polyorganosiloxane particles after growth is expressed by the relational expression (II)
R = r [K (M / m) +1]^1/3                          ... (II)
[Where r is the seed particle size (μm), K is the dilution ratio of the seed particles, and M and m are the concentrations (% by weight) of the silicon compound used in the steps (B) and (A), respectively. ]
Therefore, polyorganosiloxane particles having a desired particle size can be produced very easily. That is, the particles after growth depend on the seed particle size and the seed particle dilution rate in the seed particle liquid obtained in the step (A) and the concentration of the silicon compound used in the steps (A) and (B). The diameter is determined.
[0037]
In particular, when a nonionic surfactant is used in the generation of seed particles in the step (A), the particle size of the seed particles is determined according to the relational expression (IV), as described above. (Weight%). Therefore, the particle diameter R (μm) of the finally obtained polyorganosiloxane particles after the growth is expressed by the relational expression (III)
R = C [{K (M / m) +1} / x]^1/3                  ... (III)
[However, C is a constant determined by the reaction conditions at the time of seed particle generation, and K, M, m, and x are as defined above. ]
Can be controlled according to the above. That is, if the constant C is obtained in advance by a preliminary experiment as described above, the particle size of the grown polyorganosiloxane particles can be determined without needing to measure the particle size of the seed particles obtained in the step (A). Can be controlled.
[0038]
The pH range in the step (A) is at 30 ° C., but when using a catalyst with a low ionization degree such as ammonia, it is known depending on the temperature. And the pH range suitable for the growth reaction in the step (B) also changes in accordance with the change. Therefore, it is preferable to adjust to the optimum pH depending on the reaction temperature. A pH of 8.0 to 10.8 is preferable at 30 ° C.
[0039]
In the present invention, after the completion of the step (B), the generated particles are sufficiently washed according to a conventional method, and then, if necessary, classification treatment is performed to remove maximal particles or minimal particles, followed by drying treatment. Although there is no restriction | limiting in particular as a classification processing method, The wet classification method which classifies using the sedimentation speed changes with particle sizes is preferable. A drying process is normally performed at the temperature of the range of 100-200 degreeC. In the present invention, the agglomeration of particles does not substantially occur in this drying treatment.
[0040]
The polyorganosiloxane fine particles may be baked as necessary 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 200 to 1000 ° C., particularly 300 to 800 ° C. in an inert atmosphere such as nitrogen or in a vacuum. If this temperature is less than 200 ° C, sufficient compressive strength may not be obtained, and if it exceeds 1000 ° C, the particles may become too hard, which is not preferable. The selection of the firing temperature depends on the type of organic group constituting the particles. When the organic group is susceptible to thermal decomposition, it is desirable to treat it at a relatively low temperature in the above-mentioned firing temperature range. In the case of having an organic group that is difficult to form, it is preferable to perform the treatment at a high temperature within the above baking temperature range. In any case, an optimum condition may be selected according to the required breaking strength and elastic modulus. 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.
[0041]
The polyorganosiloxane fine particles obtained by the method of the present invention have an average particle size of usually 3 to 15 μm, preferably 4 to 10 μm, and a variation coefficient (CV value) of the particle size distribution is usually 2 It is a monodisperse particle having a spherical shape of 5% or less.
The coefficient of variation (CV value) is obtained by the following equation.
CV value (%) = (standard deviation of particle size / average particle size) × 100
[0042]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, pH of an Example and a comparative example is a value in 30 degreeC.
[0043]
Example 1
(1) Seed particle solution preparation process
A 300 ml plastic container is charged with 250 ml of an ammonia aqueous solution adjusted to pH 10.9, and 25 g of methyltrimethoxysilane is slowly added while stirring at about 60 rpm with a magnetic stirrer, and a methyltrimethoxysilane layer is formed on the upper layer. Formed. Next, this was stirred at 30 ° C. until the upper layer completely disappeared to produce seed particles. At this time, the pH of the reaction solution was 9.7.
In order to measure the particle size of the seed particles, a small amount of the reaction solution was taken, and after aging by adding 25 wt% aqueous ammonia, the particle size was measured with a Coulter counter. The average particle size was 2.43 μm. The CV value was 2.0%.
A seed particle solution was prepared by diluting the reaction solution with pure water to a dilution ratio of 20 times. The pH at this time was 9.5.
[0044]
(2) Seed particle growth process
5 liters of the seed particle solution prepared in (1) above was placed in a reaction vessel equipped with a stirrer, and 500 g of methyltrimethoxysilane was slowly added while stirring at 20 rpm to form a methyltrimethoxysilane layer on the upper layer. . After stirring at 30 ° C. until the upper layer completely disappeared, 20 ml of 20 wt% aqueous ammonia was added to terminate the reaction.
When the particle size of the particles thus obtained was measured, the average particle size was 9.10 μm and the CV value was 1.8%. The particle diameter calculated by substituting the seed particle diameter and the reaction conditions into the relational expression (II) was 9.05 μm, which almost coincided with the experimental value.
[0045]
Comparative Example 1
(1) Seed particle solution preparation process
A 300 ml plastic container is charged with 250 ml of an aqueous ammonia solution adjusted to pH 11.8. While stirring this at about 60 rpm with a magnetic stirrer, 25 g of methyltrimethoxysilane is slowly added, and a methyltrimethoxysilane layer is formed on the upper layer. Formed. Next, this was stirred at 30 ° C. until the upper layer completely disappeared to produce seed particles. At this time, the pH of the reaction solution was 10.6.
In order to measure the particle size of the seed particles, a small amount of the reaction solution was taken, and after aging by adding 25 wt% ammonia water, the particle size was measured with a Coulter counter. The CV value was 2.3%.
A seed particle solution was prepared by diluting the reaction solution with pure water to a dilution ratio of 20 times. The pH at this time was 10.4.
[0046]
(2) Seed particle growth process
5 liters of the seed particle solution prepared in (1) above was placed in a reaction vessel equipped with a stirrer, and 500 g of methyltrimethoxysilane was slowly added while stirring at 20 rpm to form a methyltrimethoxysilane layer on the upper layer. . After stirring at 30 ° C. until the upper layer completely disappeared, 20 ml of 25 wt% aqueous ammonia was added to terminate the reaction.
When the particle size of the particles thus obtained was measured, two types of particles having an average particle size of 3.1 μm and a CV value of 2.0% and an average particle size of 5.0 μm and a CV value of 1.9% were obtained. Was generated. The particle diameter calculated by substituting the seed particle diameter and the reaction conditions into the relational expression (II) was 5.6 μm, which was greatly different from the experimental value.
[0047]
Comparative Example 2
(1) Seed particle solution preparation process
In a 300 ml plastic container, 250 ml of an aqueous ammonia solution adjusted to pH 9.6 is put, and while stirring this at about 60 rpm with a magnetic stirrer, 25 g of methyltrimethoxysilane is slowly added, and a methyltrimethoxysilane layer is formed on the upper layer. Formed. Next, this was stirred at 30 ° C. until the upper layer completely disappeared to produce seed particles. At this time, the pH of the reaction solution was 8.4.
In order to measure the particle size of the seed particles, a small amount of the reaction solution was taken, and after aging by adding 25% by weight ammonia water, the particle size was measured with a Coulter counter. The average particle size was 2.7 μm. The CV value was 3.1%.
A seed particle solution was prepared by diluting the reaction solution with pure water to a dilution ratio of 20 times. The pH at this time was 8.2.
[0048]
(2) Seed particle growth process
5 liters of the seed particle solution prepared in (1) above was placed in a reaction vessel equipped with a stirrer, and 500 g of methyltrimethoxysilane was slowly added while stirring at 20 rpm to form a methyltrimethoxysilane layer on the upper layer. . After stirring at 30 ° C. until the upper layer completely disappeared, 20 ml of 25 wt% aqueous ammonia was added to terminate the reaction.
When the particle diameter of the particles thus obtained was measured, the average particle diameter was 7.4 μm, the CV value was 4.1%, and the seed particles and the growing particles were coalesced during the reaction. Thus, particles having a wide particle size distribution were obtained.
[0049]
Example 2
(1) Calculation of constant C
Aqueous ammonia solution adjusted to pH 10.6 containing 0.00005% by weight of polyoxyethylene alkyl ether surfactant [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Neugen EA-137, HLB13] in a 300 ml plastic container. While adding 250 ml, stirring this at about 60 rpm with a magnetic stirrer, 25 g of methyltrimethoxysilane was slowly added to form a methyltrimethoxysilane layer on the upper layer. Next, this was stirred at 30 ° C. until the upper layer completely disappeared, and 25 wt% aqueous ammonia was added to terminate the reaction.
[0050]
The results of performing the above operation by changing the concentration of Neugen EA-137 are shown below.
[0051]
Neugen EA-137 concentration (% by weight) 0.00005 0.0001 0.00015 0.0002
Average particle size of generated particles (μm) 2.70 2.17 1.88 1.69
From this result, the constant C was determined from the relational expression (IV) between the surfactant concentration and the average particle size of the generated particles, and C = 0.099.
[0052]
(2) Seed particle solution preparation process
In a 300 ml plastic container, 250 ml of an aqueous ammonia solution adjusted to pH 10.6 containing 0.0001% by weight of polyoxyethylene alkyl ether surfactant [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Neugen EA-137] While stirring this at about 60 rpm with a magnetic stirrer, 25 g of methyltrimethoxysilane was slowly added to form a methyltrimethoxysilane layer on the upper layer. Next, this was stirred at 30 ° C. until the upper layer completely disappeared to produce seed particles. At this time, the pH of the reaction solution was 9.4.
A seed particle solution was prepared by diluting the reaction solution with pure water to a dilution ratio of 20 times. The pH at this time was 9.2.
[0053]
(3) Seed particle growth process
5 liters of the seed particle solution prepared in (2) above was placed in a reaction vessel equipped with a stirrer, and 500 g of methyltrimethoxysilane was slowly added while stirring at 20 rpm to form a methyltrimethoxysilane layer on the upper layer. . After stirring at 30 ° C. until the upper layer completely disappeared, 20 ml of 25 wt% aqueous ammonia was added to terminate the reaction.
When the particle size of the particles thus obtained was measured, the average particle size was 4.85 μm, and the CV value was 1.8%. The particle size calculated by substituting the previously obtained C = 0.099 and the reaction conditions into the relational expression (III) was 4.80 μm, which almost coincided with the experimental value.
[0054]
Example 3
In the seed particle solution preparation step in Example 2, the same procedure was performed as in Example 2 except that the dilution rate was changed from 20 times to 40 times and the pH of the adjusted seed particle solution was set to 9.0. As a result, particles having an average particle size of 5.85 μm and a CV value of 1.7% were obtained. The particle size calculated by substituting the previously obtained C = 0.099 and the reaction conditions into the relational expression (III) was 5.88 μm, which almost coincided with the experimental value.
[0055]
Example 4
(1) Seed particle solution preparation process
In a 300 ml plastic container, 250 ml of an aqueous ammonia solution adjusted to pH 10.6 containing 0.00005% by weight of a polyoxyethylene alkyl ether surfactant [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Neugen EA-137] While stirring this at about 60 rpm with a magnetic stirrer, 25 g of vinyltrimethoxysilane was slowly added to form a vinyltrimethoxysilane layer on the upper layer. Next, this was stirred at 30 ° C. until the upper layer completely disappeared to produce seed particles. At this time, the pH of the reaction solution was 9.4.
In order to measure the particle size of the seed particles, a small amount of the reaction solution was taken and aged by adding 25% by weight of ammonia water, and then the particle size was measured with a Coulter counter. The value was 2.0%.
A seed particle solution was prepared by diluting the reaction solution with pure water to a dilution ratio of 20 times. The pH at this time was 9.2.
[0056]
(2) Seed particle growth process
5 liters of the seed particle solution prepared in the above (1) was put into a reaction vessel equipped with a stirrer, and 500 g of vinyltrimethoxysilane was slowly added while stirring at 20 rpm to form a vinyltrimethoxysilane layer on the upper layer. . After stirring at 30 ° C. until the upper layer completely disappeared, 20 ml of 25 wt% aqueous ammonia was added to terminate the reaction.
When the particle size of the particles thus obtained was measured, the average particle size was 4.07 μm and the CV value was 1.8%. The particle diameter calculated by substituting the seed particle diameter and the reaction conditions into the relational expression (II) was 4.06 μm, which almost coincided with the experimental value.
[0057]
Example 5
(1) Seed particle preparation process
In a 300 ml plastic container, 250 ml of an aqueous ammonia solution adjusted to pH 10.9 is put, and while stirring this at about 60 rpm with a magnetic stirrer, 25 g of methyltrimethoxysilane is slowly added, and a methyltrimethoxysilane layer is formed on the upper layer. Formed. Next, this was stirred at 30 ° C. until the upper layer completely disappeared to produce seed particles. At this time, the pH of the reaction solution was 9.7.
In order to measure the particle size of the seed particles, a small amount of the reaction solution was taken, and 25% by weight ammonia water was added for aging, and then the particle size was measured with a Coulter counter. The CV value was 2.0%.
[0058]
(2) Seed particle growth process
The seed particle solution obtained in the above (1) was diluted with pure water so that the dilution ratio was 5 times. The pH at this time was 9.6. Of these, 25 g of methyltrimethoxysilane was slowly added while stirring 250 ml with a magnetic stirrer at about 60 rpm, and a methyltrimethoxysilane layer was formed on the upper layer. This was stirred at 30 ° C. until the upper layer completely disappeared, and used as a second seed solution. The pH of this second seed solution was 9.5.
In order to measure the particle size of the second seed particles, a small amount of the reaction solution was taken and aged by adding 25% by weight of ammonia water, and the particle size was measured with a Coulter counter. The average particle size was 4.36 μm. The CV value was 1.9%. Further, the particle diameter calculated by substituting the seed particle diameter and the reaction conditions into the relational expression (II) was 4.42 μm, which was almost in agreement with the experimental value.
[0059]
Next, the second seed particle liquid was diluted with pure water so that the dilution ratio was 10 times. The pH at this time was 9.3. Of these, 25 g of methyltrimethoxysilane was slowly added while stirring 250 ml with a magnetic stirrer at about 60 rpm, and a methyltrimethoxysilane layer was formed on the upper layer. The mixture was stirred at 30 ° C. until the upper layer completely disappeared, and after aging by adding 25 wt% aqueous ammonia, the particle size was measured with a Coulter counter. The average particle size was 9.71 μm, and the CV value was 1.7%. Further, the particle diameter calculated by substituting the second seed particle diameter and the reaction condition into the relational expression (II) was 9.82 μm, which was almost in agreement with the experimental value.
[0060]
Examples 6-10
The polyorganosiloxane fine particles obtained in Examples 1 to 5 were calcined under the conditions shown in Table 1 to obtain calcined polyorganosiloxane fine particles.
[0061]
[Table 1]

[0062]
The polyorganosiloxane fine particles obtained after firing had a breaking strength as shown in Table 1 and were found to be particularly suitable as a spacer for a liquid crystal display device.
[0063]
【The invention's effect】
According to the method of the present invention, polyorganosiloxane fine particles having a relatively large particle size (about 4 to 10 μm) and a monodispersed particle size distribution are efficiently produced so that particles having a desired particle size can be obtained. can do.
The polyorganosiloxane fine particles obtained by the method of the present invention are suitable as spacers for liquid crystal display devices and standard particles.

Claims (6)

Formula (I)
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 to 3, and there are a plurality of R ¹ each R ¹ may be different from one another identical, if OR ² there are a plurality, each OR ² may be different even identical to each other.)
In producing polyorganosiloxane fine particles by hydrolyzing and condensing a silicon compound represented by
(A) The pH of the reaction solution at the start of the reaction is adjusted to 9.7 to 11.7, and the amount of silicon compound is set and added so that the pH is reduced by 0.7 to 1.5. And a seed particle liquid preparation step in which seed particles are generated in a pH range of 8.2 to 11.0 at the end of the reaction, and the reaction liquid is diluted to become seed particle liquids, and (B) A seed particle growth step in which the seed particle solution obtained in the step (A) is added with the silicon compound represented by the general formula (I) to grow seed particles one or more times;
A process for producing polyorganosiloxane fine particles, characterized in that The method according to claim 1, wherein the growth reaction of the seed particles in the step (B) is started after adjusting the pH in the range of 8.0 to 10.8. (A) In the step, in forming the seed particles, A method according to claim 1 or 2 is added a nonionic surfactant. The method according to claim 3 , wherein the nonionic surfactant has an HLB value (hydrophilic / lipophilic balance value) of 8 to 20. The method according to any one of claims 1 to 4 , wherein the silicon compound represented by the general formula (I) is methyltrimethoxysilane and / or vinyltrimethoxysilane. The process according to any one of claims 1 to 5, hydrolysis, the obtained particles after the condensation be sintered.