JP4491200B2 - Method for producing polyorganosiloxane particles and method for producing silica particles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing polyorganosiloxane particles and a method for producing silica particles. More specifically, the present invention relates to polyorganosiloxane particles having a particle size larger than, for example, 10 μm and monodisperse in particle size distribution, which are used as spacers and standard particles for liquid crystal display devices, organic electroluminescence elements, touch panels, and the like. The present invention relates to a method for producing efficiently, and a method for producing a silica particle for use in the above-mentioned application by firing the polyorganosiloxane particles obtained by this method.
[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 and ceramic raw materials. The use as a spacer of a display device has attracted attention and has started to be used.
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 and soft, 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.
[0003]
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.
[0004]
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 a two-layer state (see, for example, Patent Document 1).
[0005]
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.
[0006]
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.
Therefore, the present inventors have studied a method for efficiently producing polyorganosiloxane particles having a particle size of about 4 to 10 μm and a monodispersed particle size distribution so that particles having a desired particle size can be obtained. Once again, after preparing a seed particle solution by hydrolyzing and condensing a silicon compound in which a non-hydrolyzable group and a hydrolyzable alkoxyl group are bonded to a silicon atom into a uniform aqueous solution, a specific relationship is established. Based on the dilution ratio determined according to the formula, a method for growing the particles by performing a dilution operation with the aqueous solution of the silicon compound was found and a patent application was filed (see Patent Document 2).
[0007]
By the way, recently, due to a change in specifications of the liquid crystal display device, a spacer having a particle size exceeding the range of particle size (4 to 10 μm) which has been considered to be suitable as a spacer has been often increased. Further, for organic electroluminescence elements and touch panels, a spacer having a particle size of about several tens of μm is required.
[0008]
When producing polyorganosiloxane particles by hydrolyzing and condensing an organosilicon compound in an aqueous medium, when obtaining particles having a particle size larger than 10 μm, conventionally (1) When using a basic catalyst (2) A method of providing a multi-stage particle growth process in which a raw material or the like is added through a seed formation process is used. However, these methods have the following problems.
(1) When setting the concentration of the basic catalyst low
In order to form hydrolyzed / condensed particles, there is a minimum required lower limit of concentration, and when the lower limit is not reached, there is a problem that precipitation and growth of particles are not performed and aggregation occurs. Therefore, this method has its limitations.
(2) When performing the growth process in multiple stages
First, as a premise, when forming monodisperse particles, there is a limit to the particle concentration in the solution. This is because aggregation occurs when the particle concentration is high. In addition, when attempting to increase the particle size, if the particle concentration is high, for example, if an attempt is made to grow twice the particle size of the seed particles, the raw material that is 8 times the raw material required for the seed particle formation is obtained. As required, the amount of particle growth relative to the amount of raw material to be added is small, which is disadvantageous. Therefore, it is common to perform the particle growth step with the particle concentration being low after seed particle formation.
[0009]
here,
(A) When no catalyst is added in the growth process
For the above reasons, an operation of diluting the solution after the seed formation is performed. However, when the number of seed particles is reduced to increase the particle size, the catalyst concentration is reduced proportionally, and from the viewpoint of the amount of catalyst. There is a limit to the amount of growth. On the other hand, when trying to increase the amount of catalyst, it is disadvantageous from the viewpoint of increasing the number of seed particles, after all, decreasing the dilution rate of the seed solution to increase the amount of catalyst. Furthermore, from another point of view, when trying to form seed particles in a high catalyst concentration, the particle size of the seed particles becomes small, and for the above reason, a large amount of raw material is required for growth, and as a result, the particles Since there is a limit to the concentration, it will eventually be forced to dilute and the catalyst concentration will be low.
(B) On the other hand, when a catalyst is added, a clear reason is not known, but a new particle nucleus is generated every time the catalyst is added. Therefore, in proportion to the increase in the number of steps and the addition of the catalyst, a number of particles having independent particle size peaks other than the target particles are generated, resulting in a considerable yield reduction. Furthermore, there has been a limit to dramatically increasing the particle size only by the growth process.
[0010]
On the other hand, a method for producing spherical silica particles by firing polymethylsilsesquioxane powder at a temperature (500 to 1300 ° C.) at which an organic group (methyl group) in the molecule decomposes is disclosed. (For example, refer to Patent Document 3). However, in this method, when polymethylsiloxane particles are calcined by calcination, the shrinkage of the particle size is remarkable, and it is difficult to obtain the final particle size of the target silica particles with high accuracy. It was. Accordingly, the silica particles obtained by this method are used in liquid crystal display devices that require particularly high particle size accuracy [low CV value, low particle size blur (target particle size-particle size of obtained particles)]. It was unsuitable for applications such as spacers. Moreover, decomposition and desorption of organic groups occur suddenly at the time of firing, resulting in a problem that the breaking strength of the particles is reduced and the particles may be broken.
Therefore, in order to solve such problems, the present inventors first set the polyorganosiloxane particles at a temperature 100 ° C. lower than the decomposition temperature of the organic group contained therein or below the decomposition temperature of the organic group. After pre-calcining at a temperature, a method for producing silica particles that was calcined at a temperature equal to or higher than the decomposition temperature of the organic group was found, and a patent was filed (see, for example, Patent Document 4).
[0011]
[Patent Document 1]
Japanese Patent Publication No. 4-70335
[Patent Document 2]
JP 2002-80598 A
[Patent Document 3]
Japanese Patent Publication No. 5-13089
[Patent Document 4]
JP 2001-302227 A
[0012]
[Problems to be solved by the invention]
Under such circumstances, the first object of the present invention is to be used as spacers or standard particles for liquid crystal display devices, organic electroluminescence elements, touch panels, etc., and the particle size is larger than 10 μm, for example. It is an object of the present invention to provide a method for efficiently producing monodisperse polyorganosiloxane particles having a distribution.
The second object of the present invention is to produce silica particles by calcining polyorganosiloxane particles, in a method of producing high particle size accuracy [low CV value, low particle size blur (particle size of target particles-obtained). It is an object of the present invention to provide an industrially advantageous production method for producing silica particles of the particle size)]] in a short time by a simple operation without causing a decrease in fracture strength or cracking.
[0013]
[Means for Solving the Problems]
The inventors of the present invention have made extensive studies to achieve the first object, and there is a limit to increasing the particle size only by the growth process. Focusing on the fact that if the diameter is increased, the yield can be improved by reducing the number of growth steps, and further research has been conducted focusing on the possibility of obtaining larger particles in the conventional growth step. As a result, in the seed particle formation step, when preparing the seed particle formation liquid by dissolving the organosilicon compound in the aqueous medium, a very small amount of basic catalyst is added, and once the particles are precipitated, By adding an amount (concentration) of a basic catalyst, seed particles larger than when a very small amount of basic catalyst is not added can be obtained, and conventionally large-sized seed particles that could not be realized can be produced. Therefore, by forming seed particles with a large particle size and then performing a conventional growth process, it is possible to finally obtain particles with a desired particle size with a high yield, and without the growth process, the desired particle size can be obtained. It has been found that particles having a particle size of 1 can be obtained, and the first object can be achieved.
[0014]
In addition, when polyorganosiloxane particles are subjected to heat treatment to decompose the organic groups contained therein, if the temperature is immediately raised to a temperature equal to or higher than the decomposition temperature of the organic groups, the decomposition and elimination of the organic groups will rapidly occur. It may occur that the particle size is remarkably contracted, the breaking strength of the particle is lowered, or the particle is broken. In order to solve such problems, the present inventors have further researched, pre-calcined at a specific temperature, and then finally calcined at a temperature equal to or higher than the decomposition temperature of the organic group to solve the above problem. And found that the second object can be achieved.
[0015]
  The present invention has been completed based on such findings.
  That is, the present invention
(1) General formula (I)
    R¹nSi (OR²)_{Four -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 the method of producing polyorganosiloxane particles by making a silicon compound represented by the following formula: aqueous solution, hydrolyzing and condensing in the presence of a basic catalyst, when the silicon compound is dissolved in the aqueous medium, After adding 0.7 to 6.5 mass ppm of basic catalyst, preliminarily hydrolyzing and condensing,,saltAdd basic catalyst,PolyorganosiloxaneA method for producing polyorganosiloxane particles, characterized by forming particles,
(2) The method according to (1) above, comprising a step of forming seed particles composed of polyorganosiloxane particles and a step of growing the seed particles.
(3) The method according to (1) or (2) above, wherein the basic catalyst is ammonia,
(4) The method according to (1), (2) or (3) above, wherein the silicon compound represented by the general formula (I) is methyltrimethoxysilane or vinyltrimethoxysilane.
(5) The average particle diameter of the produced polyorganosiloxane particles exceeds 10 μm, and the coefficient of variation (CV value) of the particle size distribution is 5% or less. Described method,and
(6) The method according to any one of (1) to (5) aboveInReorganosiloxane particlesThe polyorganosiloxane particles produced and obtainedThe pre-baking treatment is performed at a temperature 150 ° C. lower than the decomposition temperature of the organic group contained therein or below the decomposition temperature of the organic group, and then the baking treatment is performed at a temperature equal to or higher than the decomposition temperature of the organic group. How to make silica particlesLaw
TheIt is to provide.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
First, the manufacturing method of the polyorganosiloxane particle | grains of this invention is demonstrated.
In the method of the present invention, the general formula (I) is used as a raw material.
R¹ _nSi (OR²)_4-n                                  ... (I)
The silicon compound represented by these is used.
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. Among these, those obtained as polyorganosiloxane particles and then having a small amount of organic components in the process of silicification by heat treatment due to their small particle size shrinkage and efficiency during silicification by removing organic components Is preferred. Accordingly, methyltrimethoxysilane and vinyltrimethoxysilane are preferred, and methyltrimethoxysilane is particularly preferred.
[0019]
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.
In the method of the present invention, the silicon compound is made into a substantially uniform aqueous solution, and a small amount of a basic catalyst in the order of ppm is added thereto, followed by preliminary hydrolysis and condensation, and then formation of polyorganosiloxane particles. The basic catalyst is added in an amount necessary to form the particles.
In this method, a step of forming seed particles composed of polyorganosiloxane particles (seed particle forming step) and a step of growing the seed particles (particle growing step) can be performed. In the seed particle forming step, In preparing a seed particle-forming solution by dissolving the silicon compound in an aqueous medium, a small amount of a basic catalyst in the order of ppm is added to form hydrolyzed and condensed particles of the silicon compound. A predetermined amount of a basic catalyst can be added to form seed particles.
[0020]
Next, each step will be described.
Seed particle formation process
In this step, operations of (1) preparation of seed particle formation liquid and (2) formation of seed particles are performed.
In the method of the present invention, in order to carry out seed particle formation and particle size growth in a substantially homogeneous system using an aqueous medium, as a silicon compound used for preparing a seed particle forming liquid, From the compounds represented by the general formula (I), they can be appropriately selected and used regardless of the specific gravity. When the formation of seed particles and the growth of the particle diameter are each carried out by the two-layer method, it is necessary to use a silicon compound having a specific gravity lighter than that of an aqueous medium, so that the types of raw materials are limited. However, in the present invention, since there is no such restriction on specific gravity, the degree of freedom in selecting raw materials is great.
[0021]
The silicon compound is not particularly limited as long as it is miscible with an aqueous medium, and among them, a compound that is easily soluble in an aqueous medium, for example, a silicon compound having a methoxy group is preferable. When silica particles are obtained by firing, methyltrimethoxysilane having a high silicon content is most preferable as described above.
<Preparation of seed particle formation solution>
In preparing the seed particle forming liquid, an aqueous medium is used as a solvent. As this aqueous medium, water or a mixture of water and a water-miscible organic solvent can be used. 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. In the present invention, water is usually used as the aqueous medium. When water is used, it may be tap water or ion-exchanged water. However, since the addition of a trace amount of a basic catalyst on the order of ppm plays an important role, the electrical conductivity is particularly 0.5. × 10^-4S / cm or less of ion exchange water is preferred.
[0022]
Preparation of the seed particle forming liquid is carried out by adding a small amount of a predetermined amount of a basic catalyst and a predetermined silicon compound to the aqueous medium, and stirring at a temperature of about 0 to 50 ° C. Is done. Under the present circumstances, the density | concentration of a silicon compound has preferable 20 mass% or less, and especially the range of 5-15 mass% is suitable from points, such as the particle size of the seed particle to produce | generate, and volumetric efficiency.
Examples of the basic catalyst include ammonia and amines.
[0023]
Here, preferred examples of amines include monomethylamine, dimethylamine, monoethylamine, diethylamine, and ethylenediamine. These ammonia and amines may be used alone or in combination of two or more. However, ammonia is preferred because it has low toxicity, is easy to remove, and is inexpensive.
[0024]
The addition amount of this basic catalyst is selected in the range of 0.7 to 6.5 mass ppm with respect to the aqueous medium used. When this addition amount deviates from the above range, the effect of the present invention is not exhibited. The preferred addition amount depends on the type of basic catalyst, the type of aqueous medium, the type and concentration of the silicon compound, the preparation temperature of the seed particle forming liquid, etc., but is usually in the range of 1.0 to 5.0 ppm by mass. Selected.
Further, the stirring speed at the time of preparing the seed particle forming liquid cannot be generally determined because the stirring effect varies depending on the size of the seed particle forming liquid preparation container and the size of the blades.
Furthermore, the time required to dissolve the silicon compound is not particularly limited because it depends on the temperature at the time of dissolution. However, if the dissolution time is too long, the effect of the present invention is not sufficiently exhibited.
<Formation of seed particles>
While stirring the seed particle-forming liquid prepared above, the basic catalyst is added in an amount necessary for seed particle formation and seed particle growth in the next step, and the silicon compound is hydrolyzed and condensed to form seed particles. Let it form.
[0025]
At this time, the addition amount of the basic catalyst is advantageously selected so that the pH of the seed particle liquid after formation of the seed particles is preferably in the range of 8.2 to 11.0. The reaction temperature depends on the kind of silicon compound as a raw material, but is generally selected in the range of 0 to 50 ° C.
The formation time of seed particles is usually within 1 hour. When the seed particles are formed by the two-layer method, it takes about 4 to 10 hours. However, if a method using a substantially homogeneous system as in the present invention is adopted, the seed particles can be formed in a much shorter time. it can.
After forming the seed particles in this way, a part of the seed particle liquid is collected and brought into contact with a protective colloid-forming agent to form the protective particles on the seed particles. By measuring the diameter, the average particle diameter of the seed particles can be determined.
[0026]
Here, examples of the protective colloid-forming agent include an alkylaryl sulfonate such as sodium alkylbenzene sulfonate, an alkyl sulfonate such as sodium dodecyl sulfonate, an anionic surfactant such as fatty acid soap such as sodium laurate, Examples thereof include polymer surfactants such as methacrylic acid, alginic acid, polymaleic acid, and polyvinyl alcohol. Of these, polyvinyl alcohol is particularly preferred. One of these protective colloid forming agents may be used alone, or two or more thereof may be used in combination.
In this seed particle forming step, seed particles having an average particle diameter of about 4 to 15 μm can be formed.
In this step, when a desired large particle size particle having an average particle size larger than 10 μm is obtained, the next particle growth step may not be performed.
Particle growth process
In this step, preparation of a particle growth liquid and particle diameter growth are performed.
[0027]
The particle diameter growth operation in this step may be performed in one step, or if necessary, a particle diameter control operation may be performed.
<Preparation of particle growth solution>
The particle growth liquid is prepared by adding a predetermined silicon compound to the aqueous medium and stirring it at a temperature of usually about 0 to 50 ° C. to obtain a substantially uniform aqueous solution. Under the present circumstances, the density | concentration of a silicon compound has preferable 20 mass% or less, and the range of 5-15 mass% is especially suitable from points, such as the particle size of a growth particle, and volumetric efficiency. In this particle growth liquid, the type of silicon compound, the concentration thereof, the type of aqueous medium, and the like may be the same as or different from those of the seed particle formation liquid. From the viewpoint of properties and properties of the obtained particles, the same ones are preferable.
[0028]
Furthermore, an anionic surfactant can be added to the particle growth liquid as necessary for the purpose of preventing aggregation of the grown particles. As this anionic surfactant, those having an HLB value (an index representing the balance between hydrophilicity and lipophilicity) in the range of 15 to 42 are preferable, and higher alcohol sulfates (long-chain alkyl sulfates) are more preferable. In particular, sodium dodecyl sulfate is preferred.
[0029]
When the particle diameter control operation is performed after the particle diameter growth operation, the particle growth liquid and the particle diameter control liquid may be the same or different.
<Growth of particle size>
While stirring the above-described particle growth liquid, the above-described seed particle liquid is added thereto to grow the particle diameter. 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.
[0030]
In the present invention, the growth of the particle diameter is generally sufficient within 3 hours. When the particle size is grown by adopting the two-layer method, it usually takes about 6 to 10 hours, but the particle size can be grown in a much shorter time by carrying out in a substantially uniform system as in the present invention. Can do. In the case of the two-layer method, the silicon compound in the upper layer undergoes self-condensation due to moisture in the air and changes in quality, for example, becomes a cocoon and wraps around a stirring blade, and is used for particle size growth. The amount may be reduced, and particles having a desired particle size may not be obtained. On the other hand, in the method of the present invention, since the particle diameter is grown in a substantially uniform system, such a problem does not occur.
[0031]
In the present invention, after the particles are grown in this manner, a particle size control operation can be further performed as necessary. In this case, while stirring the particle growth liquid, a particle diameter control liquid (an aqueous solution containing a predetermined silicon compound) is added to the particle growth liquid, and the particle diameter is further increased to produce polyorganosiloxane particles having a desired particle diameter. Get.
In the present invention, the end of the growth of the particle diameter is measured, for example, with an optical microscope video micrometer continuously or at regular intervals, and when the change in the particle diameter substantially disappears, It can be determined that the growth has ended.
Thus, after completion of the particle growth step, aging is performed by adding a basic catalyst to the particle growth solution. This aging is performed for about 6 to 24 hours at a normal temperature in the range of 0 to 50 ° C., although it depends on the type of silicon compound as a raw material.
[0032]
After completion of this ripening operation, the particles produced according to a conventional method are sufficiently washed, and if necessary, particles having a high particle size contained in the particles are classified and taken out and dried. 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. In addition, when polyorganosiloxane particles are finally made into silica particles, it is preferable from the viewpoint of cost and environment that the above-mentioned wet classification is performed after the formation of silica particles that can use water. 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.
The polyorganosiloxane particles obtained by the method of the present invention have an average particle size of usually larger than 10 μm, preferably 12.5 to 25 μm. Further, the coefficient of variation (CV value) of the particle size distribution is usually 5% or less, preferably 2.5% or less, and is a true spherical monodisperse particle.
[0033]
The coefficient of variation (CV value) is obtained by the following equation.
CV value (%) = (standard deviation of particle size / average particle size) × 100
Next, the manufacturing method of the silica particle of this invention is demonstrated.
This method is a method in which polyorganosiloxane particles are fired to decompose organic groups contained therein to produce silica particles, which are obtained as the polyorganosiloxane particles by the above-described production method. Polyorganosiloxane particles are used.
In this method, the polyorganosiloxane particles obtained by the above-described method are pre-fired at a temperature lower by 150 ° C. than the decomposition temperature of the organic group contained therein or below the decomposition temperature of the organic group, A silica particle is manufactured by baking at a temperature equal to or higher than the decomposition temperature of the organic group.
[0034]
Immediately raising the temperature to a temperature equal to or higher than the decomposition temperature of the organic group contained in the polyorganosiloxane particles and firing, the decomposition and desorption of the organic group occurs abruptly, and the breaking strength of the particle is reduced. It may not be able to withstand rapid contraction and may lead to undesirable situations such as particle breakage. However, as in the present invention, the pre-baking process is performed at a temperature 150 ° C. lower than the decomposition temperature of the organic group or lower than the decomposition temperature of the organic group, and then the baking process is performed at a temperature equal to or higher than the decomposition temperature of the organic group. Thus, the above-mentioned undesirable situation can be avoided. The selection of the calcination temperature depends on the type of organic group constituting the polyorganosiloxane particle, and when it has an organic group that is easily thermally decomposed, it is desirable to treat it at a relatively low temperature, and conversely, it is difficult to thermally decompose. When it has an organic group, it is preferably treated at a high temperature. In any case, an optimum condition may be selected according to the required breaking strength and elastic modulus. Specifically, in the case of polymethylsilsesquioxane (PMSO) particles, pre-baking treatment is performed at a temperature in the range of 250 to 350 ° C. for about 3 to 50 hours, and then in a range of 500 to 1000 ° C. The organic group is completely decomposed by baking at a temperature for about 3 to 50 hours.
[0035]
The atmosphere in the baking treatment is preferably such that the oxygen concentration is a certain level or higher, for example, 10% by volume or higher, in order to oxidize and decompose the organic group. Moreover, there is no restriction | limiting in particular about a baking apparatus, Well-known baking apparatuses, such as an electric furnace and a rotary kiln, can be used.
[0036]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Example 1
(1) Preparation of seed particle formation solution
To 5,000 g of ion-exchanged water, 0.8 ml of 1 mol / liter ammonia water (NH₃: 2.7 ppm) and 500 g of methyltrimethoxysilane (hereinafter abbreviated as MTMS) were added and stirred at 25 ° C. at 100 rpm. After about 3 hours, MTMS was completely dissolved to become a homogeneous solution, and it became pale and cloudy. This was used as a seed particle forming solution. The particle size distribution of the fine particles in the seed particle forming liquid was measured with a Coulter counter (“Multisizer III” manufactured by Beckman Coulter, Inc.). This particle size distribution chart is shown in FIG.
(2) Preparation of liquid for particle growth
MTMS 4,950g was added to ion exchange water 33,000g, and it stirred at 100 rpm at 30 degreeC. After about 3 hours, MTMS was completely dissolved to form a uniform solution, which was used as a particle growth solution.
(3) Formation of seed particles
In the seed particle forming solution prepared in the above (1), the stirring speed was lowered to 30 rpm, and 50 ml of 1 mol / liter ammonia water was added all at once. 0.2 ml of the seed particle solution 20 minutes after the addition is added to 2 ml of 0.1% by weight polyvinyl alcohol aqueous solution, and the particle size distribution of the seed particles in the seed particle solution is measured by a Coulter counter (“Multi” manufactured by Beckman Coulter, Inc. Measured with sizer III "). This particle size distribution chart is shown in FIG. The seed particles had an average particle size of 5.477 μm and a CV value of 2.57%.
(4) Particle growth
While stirring the whole liquid for particle growth of (2) at 20 rpm, 5,528 g of the seed particle liquid obtained in (3) above was added thereto.
(5) Stop reaction
From the addition of the seed particle solution in (4) above, the particle diameter was measured every 10 minutes with an optical microscope video micrometer (Olympus Video Micrometer “VM-50”). After 30 minutes and 35 minutes from the addition, the average particle diameter was about 14.8 μm, and it was judged that the growth of the particle diameter was completed. It was dripped and aged.
[0037]
The particle size distribution of the polymethylsilsesquioxane (PMSO) particles thus obtained was measured with a Coulter counter (“Multisizer III” manufactured by Beckman Coulter, Inc.). This particle size distribution chart is shown in FIG. The average particle diameter of the PMSO particles was 14.73 μm, and the CV value was 1.63%.
(6) Classification and drying of fine particles
The obtained particles were subjected to solid-liquid separation with a centrifugal separator, and then, after irradiating ultrasonic waves in methanol, the operation of decantation was repeated several times to remove fine particles. The remaining particles were air-dried and then dried at 150 ° C. to remove residual methanol. The yield of PMSO particles thus obtained was 70%.
Example 2
The PMSO particles obtained in Example 1 were heated from room temperature to 300 ° C. under the condition of an air flow rate of 1 liter / min, kept at that temperature for 24 hours and pre-baked, then heated to 550 ° C., The main calcination was carried out at that temperature for 9 hours. After the main firing, the product was cooled to room temperature, and the fired particles were taken out. When this fired particle is dispersed in water and left for a certain period of time, it is divided into three layers: a layer containing the most abundant particles, and a layer containing only larger particles and only smaller particles. become. In this state, the operation of first extracting and removing a layer of small particles was repeated until the layer became transparent, and particles smaller than the target particle were removed. For the remaining layer, only the target particles are included in the vicinity of the interface with the transparent supernatant without particles due to the difference in the sedimentation rate depending on the volume, so the operation of extracting this part is repeated to separate only the target particles. did. The particles obtained after classification were measured with a Coulter counter (“Multisizer III” manufactured by Beckman Coulter, Inc.). As a result, the average particle size was 11.93 μm, and the CV value was 1.75%. there were.
Example 3
(1) Preparation of seed particle formation solution
To 5,000 g of ion-exchanged water, 0.8 ml of 1 mol / liter ammonia water (NH₃: 2.7 ppm), and 500 g of MTMS was added and stirred at 25 ° C. at 100 rpm. After about 3 hours, MTMS was completely dissolved to become a homogeneous solution, and it became pale and cloudy. This was used as a seed particle forming solution.
(2) Preparation of liquid for particle growth
To 26,400 g of ion-exchanged water, 3,960 g of MTMS was added and stirred at 30 ° C. at 100 rpm. After about 3 hours, MTMS was completely dissolved to form a homogeneous solution, to which 13.2 g of sodium dodecyl sulfate was added. This was used as a particle growth solution.
(3) Preparation of particle size control liquid
To 8,000 g of ion-exchanged water, 1,200 g of MTMS was added and stirred at 100 rpm at room temperature. After about 3 hours, MTMS completely dissolved and became a homogeneous solution. This was used as a particle size controlling liquid.
(4) Formation of seed particles
In the seed particle forming solution prepared in the above (1), the stirring speed was lowered to 30 rpm, and 50 ml of 1 mol / liter ammonia water was added all at once. 0.2 ml of the seed particle solution 20 minutes after the addition was added to 2 ml of 0.1% by weight polyvinyl alcohol aqueous solution, and the particle size of the seed particles in the seed particle solution was measured by a Coulter counter (“Multisizer, manufactured by Beckman Coulter, Inc.). III "). As a result, the seed particles had an average particle size of 7.184 μm and a CV value of 2.37%.
(5) Particle growth
While stirring the whole liquid for particle growth (2) at 20 rpm, 5,525 g of the seed particle liquid obtained in (4) was added thereto. 30 minutes after the addition of the seed particle solution, 0.2 ml of the particle growth solution is added to 2 ml of 0.1% by weight polyvinyl alcohol aqueous solution, and the particle size is measured with a Coulter counter ("Multisizer III" manufactured by Beckman Coulter, Inc.). Was measured. As a result, the average particle size was 13.37 μm, the CV value was 1.14%, and the particle size was slightly smaller than the target size.
(6) Particle size control and reaction stop
The particle size control solution of (3) above is dropped into the particle growth solution of (5) with a metering pump over about 40 minutes, and a Coulter counter (“Multi” manufactured by Beckman Coulter, Inc. is used in the same manner as (5) above. Particle size growth was observed with sizer III "). The target average particle size of 14.83 μm (CV value 0.97%) was obtained 120 minutes after the start of dropping. In order to stop the growth of the particle diameter, 1000 g of 2.5% by mass ammonia water was dropped with a metering pump and aging was performed.
[0038]
When the particle diameter of the particles thus obtained was measured with a Coulter counter (“Multisizer III” manufactured by Beckman Coulter, Inc.), the average particle diameter was 14.80 μm, and the CV value was 1.93%. there were.
(7) Classification and drying of fine particles
The obtained particles were subjected to solid-liquid separation with a centrifugal separator, and then, after irradiating ultrasonic waves in methanol, the operation of decantation was repeated several times to remove fine particles. The remaining particles were air-dried and then dried at 150 ° C. to remove residual methanol. The yield of PMSO particles thus obtained was 75%.
Example 4
By subjecting the PMSO particles obtained in Example 3 to the same firing and classification operations as in Example 2, fired particles having an average particle diameter of 11.99 μm and a CV value of 1.85% are obtained. It was.
Example 5
(1) Preparation of seed particle formation solution
To 5,000 g of ion-exchanged water, 0.8 ml of 1 mol / liter ammonia water (NH₃: 2.7 ppm) and 750 g of MTMS were added and stirred at 25 ° C. at 100 rpm. After about 3 hours, MTMS was completely dissolved to become a homogeneous solution, and it became pale and cloudy. This was used as a seed particle forming solution.
(2) Preparation of liquid for particle growth
MTMS 4,950g was added to ion exchange water 33,000g, and it stirred at 100 rpm at 30 degreeC. After about 3 hours, MTMS was completely dissolved to form a homogeneous solution, to which 16.5 g of sodium dodecyl sulfate was added. This was used as a particle growth solution.
(3) Formation of seed particles
In the seed particle forming solution prepared in the above (1), the stirring speed was lowered to 50 rpm, and 50 ml of 1 mol / liter ammonia water was added all at once. 0.2 ml of the seed particle solution 20 minutes after the addition was added to 2 ml of 0.1% by weight polyvinyl alcohol aqueous solution, and the particle size of the seed particles in the seed particle solution was measured by a Coulter counter (“Multisizer, manufactured by Beckman Coulter, Inc.). III "). As a result, the seed particles had an average particle diameter of 11.11 μm and a CV value of 2.19%.
(4) Particle growth
While stirring the total amount of the particle growth liquid (2) at 20 rpm, 5,778 g of the seed particle liquid obtained in (3) above was added thereto.
(5) Stop reaction
From the addition of the seed particle solution in (4) above, the particle diameter was measured every 10 minutes with an optical microscope video micrometer (Olympus Video Micrometer “VM-50”). After 60 minutes and 65 minutes from the addition, the average particle diameter was both about 23.6 μm, and it was judged that the growth of the particle diameter was completed, and 1,000 g of 2.5 mass% aqueous ammonia was added using a metering pump. It was dripped and aged.
[0039]
The particle size distribution of the polymethylsilsesquioxane (PMSO) particles thus obtained was measured with a Coulter counter (“Multisizer III” manufactured by Beckman Coulter, Inc.). This particle size distribution chart is shown in FIG. The average particle diameter of the PMSO particles was 23.30 μm, and the CV value was 1.81%.
(6) Classification and drying of fine particles
The obtained particles were subjected to solid-liquid separation with a centrifugal separator, and then, after irradiating ultrasonic waves in methanol, the operation of decantation was repeated several times to remove fine particles. The remaining particles were air-dried and then dried at 150 ° C. to remove residual methanol. The yield of PMSO particles thus obtained was 65%.
Comparative Example 1
(1) Preparation of seed particle formation solution
To 5,000 g of ion-exchanged water, 0.2 ml of 1 mol / liter ammonia water (NH₃: 0.68 ppm), and 500 g of MTMS was added and stirred at 25 ° C. at 100 rpm. After about 3 hours, MTMS was completely dissolved to become a homogeneous solution and became transparent. This was used as a seed particle forming solution.
(2) Formation of seed particles
In the seed particle forming solution prepared in the above (1), the stirring speed was lowered to 30 rpm, and 50 ml of 1 mol / liter ammonia water was added all at once. 0.2 ml of the seed particle solution 20 minutes after the addition was added to 2 ml of a 0.1% by weight polyvinyl alcohol aqueous solution, and the particle size of the seed particles in the seed particle solution was measured using a Coulter counter (“Multisizer, manufactured by Beckman Coulter, Inc.). III "). As a result, the seed particles had an average particle size of 2.165 μm and a CV value of 3.95%.
Comparative Example 2
(1) Preparation of seed particle formation solution
To 5,000 g of ion-exchanged water, 2.0 ml of 1 mol / liter ammonia water (NH₃: 6.8 ppm), and MTMS (500 g) was added and stirred at 25 ° C. and 100 rpm. After about 3 hours, MTMS was completely dissolved and became a homogeneous solution, and became deep cloudy. This was used as a seed particle forming solution.
(2) Formation of seed particles
In the seed particle forming solution prepared in the above (1), the stirring speed was lowered to 30 rpm, and 50 ml of 1 mol / liter ammonia water was added all at once. 0.2 ml of the seed particle solution 20 minutes after the addition was added to 2 ml of 0.1% by weight polyvinyl alcohol aqueous solution, and the particle size of the seed particles in the seed particle solution was measured by a Coulter counter (“Multisizer, manufactured by Beckman Coulter, Inc.). III "). As a result, the seed particles had an average particle diameter of 2.176 μm and a CV value of 4.21%.
Comparative Example 3
(1) Preparation of seed particle formation solution
MTMS 500g was added to ion exchange water 5,000g, and it stirred at 100 rpm at 25 degreeC. After about 3 hours, MTMS was completely dissolved into a homogeneous solution and became clear. This was used as a seed particle forming solution.
(2) Preparation of liquid for particle growth
MTMS 4,950g was added to ion exchange water 33,000g, and it stirred at 100 rpm at 30 degreeC. After about 3 hours, MTMS was completely dissolved to form a uniform solution, which was used as a particle growth solution.
(3) Formation of seed particles
In the seed particle forming solution prepared in the above (1), the stirring speed was lowered to 30 rpm, and 50 ml of 1 mol / liter ammonia water was added all at once. After 30 minutes of addition, 0.2 ml of the seed particle solution was added to 2 ml of a 0.1% by weight polyvinyl alcohol aqueous solution, and the particle size of the seed particles in the seed particle solution was measured using a Coulter counter (“Multisizer, manufactured by Beckman Coulter, Inc.). III "). As a result, the seed particles had an average particle size of 2.365 μm and a CV value of 1.56%.
(4) Particle growth
While stirring the whole liquid for particle growth (2) at 20 rpm, 3,200 g of the seed particle liquid obtained in (3) above was added thereto.
(5) Stop reaction
From the addition of the seed particle solution in (4) above, the particle diameter was measured every 10 minutes with an optical microscope video micrometer (Olympus Video Micrometer “VM-50”). 30 minutes and 35 minutes after the addition, the average particle size was about 7.2 μm, and it was judged that the particle size growth had ended, and 500 g of 2.5% by mass ammonia water was added dropwise with a metering pump. And matured.
[0040]
When the particle diameter of the PMSO particles thus obtained was measured with a Coulter counter, the average particle diameter was 7.052 μm and the CV value was 1.65%.
(6) Classification and drying of fine particles
The obtained particles were subjected to solid-liquid separation with a centrifugal separator, and then, after irradiating ultrasonic waves in methanol, the operation of decantation was repeated several times to remove fine particles. The remaining particles were air-dried and then dried at 150 ° C. to remove residual methanol. The yield of PMSO particles thus obtained was 70%.
Comparative Example 4
(1) Preparation of additive-containing liquid
To 450 g of ion-exchanged water, 45 g of MTMS was added and stirred at 100 rpm at room temperature. At the beginning of MTMS addition, it was dispersed in the form of oil droplets in the aqueous solution, but after about 2 hours, MTMS was completely dissolved and became a homogeneous solution. The stirring speed was reduced to 40 rpm, and 0.72 ml of 1 mol / liter ammonia water was added all at once. 15 minutes after adding the aqueous ammonia, the particles grew and the solution became cloudy. After 30 minutes, the particle size was measured with an optical microscope video micrometer (Olympus Video Micrometer “VM-50”), and the average particle size was 4.1 μm.
(2) Preparation of seed particle formation solution
MTMS500g was added to ion exchange water 5000g, and it stirred at 100 rpm at 30 degreeC. After about 3 hours, MTMS was completely dissolved into a uniform solution, which was used as a seed particle forming solution.
(3) Preparation of liquid for particle growth
MTMS 4950g was added to ion exchange water 33000g, and it stirred at 100 rpm at 20 degreeC. After about 3 hours, MTMS was completely dissolved to form a uniform solution, which was used as a particle growth solution.
(4) Formation of seed particles
In the seed particle forming liquid prepared in (2) above, the stirring speed was lowered to 30 rpm, and 50 ml of 1 mol / liter of ammonia water and 493 g of the additive particle-containing liquid obtained in (1) above were added. After 30 minutes of addition, 0.2 ml of the seed particle solution was added to 2 ml of a 0.1% by weight polyvinyl alcohol aqueous solution, and the particle size was immediately measured with a Coulter counter (“Multisizer III” manufactured by Beckman Coulter, Inc.). As a result, newly generated seed particles had an average particle size of 4.456 μm (CV value 1.16%).
(5) Growth of particle size
While stirring the total amount of 37950 g of the particle growth liquid obtained in (3) above at 20 rpm, 3410 g of the seed particle liquid obtained in (4) above was added to grow the particle size.
(6) Stop reaction
The particle diameter was measured with an optical microscope video micrometer (Olympus Video Micrometer “VM-50”) every 10 minutes after the addition of the seed particle forming solution in (5) above. After 1 hour and 1 hour and 10 minutes from the addition, both had an average particle size of about 13.8 μm, and the occurrence of aggregates was confirmed. Aging was performed by dropping 500 g of aqueous ammonia with a metering pump.
[0041]
The particle diameter of the particles thus obtained was measured with a Coulter counter (“Multisizer III” manufactured by Beckman Coulter, Inc.). The average particle diameter was 13.88 μm, and the CV value was 1.56%. It was.
(7) Classification and drying of fine particles
The obtained particles were subjected to solid-liquid separation with a centrifugal separator, and then, after irradiating ultrasonic waves in methanol, the operation of performing decantation was repeated several times to remove fine particles. The remaining particles were air-dried and then dried at 150 ° C. to remove residual methanol. The yield of PMSO particles thus obtained was 30%.
Comparative Example 5
By subjecting the PMSO particles obtained in Comparative Example 4 to the same firing and classification operations as in Example 2, fired particles having an average particle diameter of 11.31 μm and a CV value of 1.47% are obtained. It was.
[0042]
【The invention's effect】
According to the present invention, seed particles having a particle size larger than that of the conventional method can be formed by adding a trace amount of a basic catalyst in the order of ppm when preparing the seed particle forming liquid. By growing the seed particles or, if necessary, no growth operation is performed, polyorganosiloxane particles having an average particle size larger than, for example, 10 μm and a monodisperse particle size distribution can be efficiently produced. The polyorganosiloxane particles are used as spacers and standard particles for liquid crystal display devices, organic electroluminescence elements, touch panels, and the like.
In addition, according to the method of the present invention, the polyorganosiloxane particles obtained by the above method are fired under specific conditions to have a particle size suitable for the above-mentioned use and a high particle size distribution. Monodispersed silica particles can be produced in a short time by a simple operation.
[Brief description of the drawings]
FIG. 1 is a particle size distribution chart obtained by measuring the particle size of fine particles in a seed particle forming liquid in Example 1 using a Coulter counter.
FIG. 2 is a particle size distribution chart obtained by measuring the particle size of seed particles in the seed particle liquid in Example 1 using a Coulter counter.
FIG. 3 is a particle size distribution chart obtained by measuring the particle size of polymethylsilsesquioxane particles in the particle growth liquid in Example 1 using a Coulter counter.

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 is 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 the method for producing polyorganosiloxane particles by hydrolyzing and condensing a silicon compound represented by the following formula in the presence of a basic catalyst, when the silicon compound is dissolved in the aqueous medium, with the addition of 0.7 to 6.5 mass ppm of a basic catalyst, preliminary hydrolysis, after condensation, to this is added salt group catalyst, that to form the polyorganosiloxane particles A method for producing polyorganosiloxane particles, which is characterized.   The method according to claim 1, comprising the steps of forming seed particles composed of polyorganosiloxane particles and growing the seed particles.   The process according to claim 1 or 2, wherein the basic catalyst is ammonia.   The method according to claim 1, 2 or 3, wherein the silicon compound represented by the general formula (I) is methyltrimethoxysilane or vinyltrimethoxysilane.   The method according to any one of claims 1 to 4, wherein the produced polyorganosiloxane particles have an average particle size of more than 10 µm and a coefficient of variation (CV value) of the particle size distribution of 5% or less. Claims 1 to produce a method depot polyorganosiloxane particles according to any one of 5, obtained poly organosiloxane particles, 0.99 ° C. lower temperature to organic than the decomposition temperature of the organic groups contained therein A method for producing silica particles, comprising pre-calcining at a temperature lower than the decomposition temperature of the group and then baking at a temperature equal to or higher than the decomposition temperature of the organic group.

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