JP2011202181A - Method of preparing silica particles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of preparing silica particles in which the whole surfaces of base particles have protrusions firmly bound to the base particles by chemical bonding, and which are suitable for, for example, a filler for resin or a matrix of a conductive particle having a surface coated with a conductive layer.SOLUTION: The method of preparing silica particles includes: (A) a step of hydrolyzing and condensing a specific alkoxysilane compound and thereby creating polyorganosiloxane particles; (B) a step of surface-treating the created polyorganosiloxane particles by a surface adsorbent; and (C) a step of forming protrusions on the whole surfaces of the polyorganosiloxane particles surface-treated in the step (B) using, the alkoxysilane compound.

Description

  The present invention relates to a method for producing silica-based fine particles. More specifically, the present invention is such that substantially spherical or hemispherical projections are firmly bonded to the entire surface of the base particle by chemical bonding, and for example, a conductive material having a conductive layer coated on a resin filler or the surface. The present invention relates to a method for efficiently producing silica-based fine particles suitable as a base material for particles.

Conventionally, in a semiconductor resin sealant, a radial tire, and the like, various fillers are mixed for the purpose of improving performance. As the filler, inorganic particles and glass fibers are mainly used.
When the filler is a spherical particle or a gold plain sugar-like particle, when these are used as a filler for a semiconductor resin sealant or a radial tire, the adhesion with a resin composition or a rubber composition, or thermal expansion The latter is superior in terms of the effect of preventing the occurrence of cracks due to the coefficient difference.

  Conventionally, regarding the production of confetti particles, for example, (1) by polymerizing a monomer in the presence of dispersion polymer particles obtained by a dispersion polymerization method, fine polymer particles are formed on the surface of the dispersion polymer particles. Resin particles having irregularities on the surface to be adhered (Patent Document 1), (2) Adhering the child particles to the surface of the mother particles with an adhesive or directly fusing them to have protrusions on the surface A method for producing fine particles, or a mother particle is placed in a rotating container, a solution of child particles is attached to the surface of the particle, and the solvent is evaporated while the container is rotated, so that the solute is squared on the mother particle surface A method for producing fine particles having projections by precipitation (Patent Document 2), (3) Fusing spherical silica particles and crushed silica particles finer than the silica particles are charged into a high-speed rotating air stream, Particles with protrusions on the particle surface It discloses a method of making (Patent Document 3).

However, the resin particles having irregularities on the surface of (1) have a defect that the shear strength and breaking strength of the particles themselves or the projections are poor, and on the other hand, they are obtained by the methods (2) and (3). The particles having protrusions on the surface have the disadvantage that the base particles and the protrusions are bonded by physical adhesion or fusion, and thus the protrusions have poor shear strength and breaking strength. In the method (3), since the treatment is performed under a high-speed rotating air current, there is a problem that the heat resistance and pressure resistance of the particles themselves are required.
When such confetti particles are used as a filler, a difference in mechanical strength such as breaking strength of the product itself is caused by a difference in bond strength between the base particle surface and the protrusion.

JP-A-5-331216 JP-A-4-36902 JP-A-3-259960

  Under such circumstances, the present invention is such that protrusions are firmly bonded by chemical bonding over the entire surface of the base particle, for example, a filler for a resin or a base of a conductive particle having a surface coated with a conductive layer. An object of the present invention is to provide silica-based fine particles suitable as a material.

  As a result of intensive studies to achieve the above object, the present inventors have hydrolyzed an alkoxysilane compound having a specific structure to produce polyorganosiloxane particles, and surface-treated the polyorganosiloxane particles. Step, using the surface-treated polyorganosiloxane particles as seed particles, forming protrusions using an alkoxysilane compound on the entire surface of the particles, and optionally performing a firing treatment step, so that the entire surface of the base particles is substantially spherical. In addition, the inventors have found that silica-based fine particles can be obtained in which hemispherical protrusions are firmly bonded by chemical bonding, and the present invention has been completed based on this finding.

That is, the present invention is a method for producing silica-based fine particles that have substantially spherical and / or hemispherical protrusions on the entire surface of the base particles, and the protrusions are bound to the base particles by chemical bonds. And
(A) General formula (I)
R ¹ nSi (OR ² ) _4-n (I)
(In the formula, R ¹ is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, and R ² has 1 to 1 carbon atoms. 5 alkyl group, n represents 1 or 2, and when n is 2, two R ^{1 s} may be the same or different, and a plurality of OR ² may be the same or different .)
A step of hydrolyzing and condensing the alkoxysilane compound represented by the following, and optionally growing particles as seed particles to produce polyorganosiloxane particles:
(B) a step of surface-treating the polyorganosiloxane particles obtained in the step (A) with a surface adsorbent, and (C) the polyorganosiloxane particles surface-treated in the step (B) as seed particles, Using the alkoxysilane compound represented by the general formula (I), a step of forming protrusions on the entire surface of the seed particles, and optionally (D) a baking treatment step,
It is characterized by including.

  According to the present invention, confetti-like silica-based fine particles in which substantially spherical or hemispherical protrusions are firmly bound by chemical bonding over the entire surface of the base particles can be easily obtained. The silica-based fine particles can be suitably used, for example, as a filler for resin or a base material for conductive particles whose surface is covered with a conductive layer.

In Example 1, it is a scanning electron micrograph figure of the silica type microparticles | fine-particles obtained by the modification process. In Example 2, it is a scanning electron micrograph figure of the silica type microparticles | fine-particles obtained by the shaping process. In Example 3, it is a scanning electron micrograph figure of the silica type microparticles | fine-particles obtained by the modification process.

The silica-based fine particles obtained by the production method of the present invention are gold flat sugar particles in which substantially spherical and / or hemispherical projections are firmly bound by chemical bonds over the entire surface of the base particles.
In silica-based fine particles, both protrusions and base particles are usually represented by the general formula (I)
R ¹ nSi (OR ² ) _4-n (I)
It has the composition derived from the alkoxysilane compound represented by these. In this case, the raw material alkoxysilane compound that forms the protrusions and the raw material alkoxysilane compound that forms the base particles may be the same or different.

In the general formula (I), R ¹ represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms. Here, the alkyl group having 1 to 5 carbon atoms may be linear or branched, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Examples include isobutyl group, sec-butyl group, tert-butyl group and various pentyl groups. The alkenyl group having 2 to 5 carbon atoms may be either linear or branched, and examples thereof include a vinyl group, an allyl group, a butenyl group, and a pentenyl group. Examples of the aryl group having 6 to 10 carbon atoms include phenyl group, tolyl group, xylyl group, and naphthyl group. Examples of the aralkyl group having 7 to 10 carbon atoms include benzyl group, phenethyl group, and phenylpropyl. Group, naphthylmethyl group and the like.

On the other hand, R ² is an alkyl group having 1 to 5 carbon atoms, and this alkyl group may be linear or branched, and examples thereof include a methyl group, an ethyl group, an n-propyl group, Examples thereof include isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group and various pentyl groups. n is 1 or 2, and when n is 2, two R ^{1 s} may be the same or different, and a plurality of OR ² may be the same or different.

  Examples of the alkoxysilane compound represented by the general formula (I) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyl Examples include triethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, dimethyldimethoxysilane, and methylphenyldimethoxysilane. Of these, methyltrimethoxysilane and vinyltrimethoxysilane are particularly preferred.

In the present invention, as a raw material, one kind of alkoxysilane compound represented by the general formula (I) may be used, or two or more kinds may be used in combination.
The base particles in the silica-based fine particles of the present invention have an average particle size of usually 0.5 to 30 μm, preferably 2 to 10 μm, and a variation coefficient (CV value) of the particle size distribution is usually 5% or less. Thus, it is a true spherical monodisperse particle.

The coefficient of variation (CV value) is obtained by the following equation.
CV value (%) = (standard deviation of particle size / average particle size) × 100
The protrusions bonded to the entire surface of the base particles by chemical bonds have a substantially spherical and / or hemispherical shape, and the average value of the height of the protrusions / the base particle diameter is Usually, it is in the range of 0.02 to 0.5. The number of protrusions bound to one base particle depends on the height / base particle diameter value of the protrusion and is not particularly limited.

Furthermore, when the silica-based fine particles are completely silicified, the nitrogen adsorption specific surface area is about twice or more that of the conventional spherical silica-based particles (having no protrusions) having the same particle diameter. growing.
Silica-based fine particles having such a shape can be efficiently produced by the production method of the present invention described below.

  The method for producing silica-based fine particles of the present invention is applied to (A) a production process of polyorganosiloxane particles, (B) a surface treatment process of the polyorganosiloxane particles, (C) a protrusion formation process, and optionally ( D) A firing process step is included, and each step will be described next.

(A) Polyorganosiloxane particle production step In this step (A), the alkoxysilane compound represented by the general formula (I) is hydrolyzed and condensed, and the resulting particles may be used as seed particles. It is a step of growing to produce polyorganosiloxane particles.

  In this step (A), the alkoxysilane compound represented by the general formula (I) is hydrolyzed and condensed in the presence of an aqueous solution of ammonia and / or amine containing a nonionic surfactant if desired. However, the above ammonia and amine are catalysts for the hydrolysis / condensation reaction of the alkoxysilane 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.

Examples of the aqueous solution of ammonia and / or amine containing a nonionic surfactant include a solution obtained by dissolving a nonionic surfactant and ammonia and / or amine in water or a mixed solvent of water and a water-miscible organic solvent. It is done. Here, examples of the water-miscible organic solvent include lower alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, dimethyl ketone and methyl ethyl ketone, and ethers such as diethyl ether and dipropyl ether. It is done. These may be mixed with water alone or in combination of two or more with water.
The amount of ammonia or amine used is not particularly limited, but is preferably selected so that the pH of the aqueous layer before starting the reaction is in the range of 7.5 to 11.0.

  In the present invention, as the nonionic surfactant used as desired, 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. When the HLB value deviates from the above range, the effect of the present invention is not sufficiently exhibited. In order to exhibit the effect of this invention better, what has a HLB value in the range of 10-17 is preferable.

  There are no particular restrictions on the reaction format, and both mixed homogeneous reaction and two-layer reaction can be used. From the viewpoint of obtaining particles having a small CV value, good particle size accuracy, and easy reaction operation. A two-layer reaction is more advantageous.

In this two-layer reaction, a raw material alkoxysilane compound having a specific gravity (23 ° C.) of 1 or less represented by the general formula (I) is used.
First, the alkoxysilane compound is reacted at the interface while maintaining a two-layer state without substantially mixing the nonionic surfactant used as desired with the ammonia and / or amine-containing aqueous solution.

In this reaction, it is necessary to gently stir the alkoxysilane compound and the ammonia or amine aqueous solution layer so that the two-layer state is maintained without substantially mixing. As a result, the upper alkoxysilane compound is hydrolyzed and transferred to the lower layer, where polyorganosiloxane particles grow. The reaction temperature at this time depends on the type of the alkoxysilane compound as a raw material, but is generally selected in the range of 0 to 60 ° C.
In this two-layer reaction, after the upper alkoxysilane compound disappears, it is supplied to the next step.

  In the step (A) of the present invention, if necessary, the particles obtained in this manner may be used as seed particles and further grown in particle size. In this case, after generating seed particles, the reaction liquid is diluted with an aqueous medium so that the dilution ratio is preferably 2 to 200 times, more preferably 5 to 100 times, to prepare seed particle liquids. 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. .

  Next, the alkoxysilane compound represented by the general formula (I) is added to the seed particle liquid, and a two-layer reaction is performed in the same manner as described above to grow seed particles. This operation can be repeated until the desired particle size is grown.

(B) Surface treatment process of polyorganosiloxane particles In this process (B), the polyorganosiloxane particles obtained in the process (A) are surface treated with a surface adsorbent.

  As the surface adsorbent used in this case, for example, polyvinyl alcohol, polyvinyl pyrrolidone and a surfactant can be preferably mentioned. The polyvinyl alcohol has a saponification degree of preferably 34 to 98 mol%, more preferably 88 to 98 mol%, and a number average molecular weight of preferably 200 to 3,500, more preferably 500 to 2,400. Are suitable. Further, as the polyvinyl pyrrolidone, those having a number average molecular weight in the range of preferably 10,000 to 360,000, more preferably 40,000 to 120,000 are suitable.

  On the other hand, nonionic and anionic surfactants are preferably used as the surfactant. 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. When the HLB value deviates from the above range, the effect of the present invention is not sufficiently exhibited. In order to exhibit the effect of this invention better, what has a HLB value in the range of 10-17 is preferable.

  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.

  Moreover, as an anionic surfactant, what has the HLB value in the range of 18-42 is used. When the HLB value deviates from the above range, the effect of the present invention is not sufficiently exhibited. Such an anionic surfactant is not particularly limited as long as the HLB value is in the range of 18 to 42, but examples thereof include alkylaryl sulfonates, alkyl sulfates, fatty acid alkali salts, alkyl phosphates, Examples thereof include alkylphosphonates. Among these, alkyl aryl sulfonates having 8 to 18 carbon atoms in the alkyl group, alkyl sulfates having 8 to 18 carbon atoms in the alkyl group, and fatty acid alkali salts having 8 to 18 carbon atoms in the alkyl group are preferable. In particular, sodium dodecyl sulfate, dodecyl benzene sulfonate, and potassium oleate are preferred. Moreover, this anionic surfactant may be used independently and may be used in combination of 2 or more type.

In the step (B), after stirring and mixing the polyorganosiloxane particle liquid obtained in the step (A) and the aqueous solution containing the surface adsorbent, ammonia and / or amine is added, preferably 20 to Surface treatment is performed by aging at a temperature of 60 ° C. for about 1 to 20 hours. At this time, the concentration of the surface adsorbent in the mixed solution is preferably in the range of 0.1 to 5% by weight.
The surface-treated polyorganosiloxane particles are preferably isolated and then supplied to the projection forming step of the next step.

(C) Projection formation step In this (C) step, the polyorganosiloxane particles surface-treated in the step (B) are used as seed particles, and the alkoxysilane compound represented by the general formula (I) is hydrolyzed. , And condensing to form protrusions on the entire surface of the seed particles (base particles).
In the step (C), either a mixed homogeneous reaction or a two-layer reaction can be used, but the two-layer reaction is more advantageous as in the step (A).

  In this two-layer reaction, first, the surface-treated polyorganosiloxane particles obtained in the step (B) are placed in an aqueous solution containing a dispersant such as polyvinyl alcohol and ammonia and / or amine, which are used as desired. An aqueous liquid to be dispersed is prepared. Next, the alkoxysilane compound represented by the general formula (I) is reacted at the interface while maintaining the two-layer state without being substantially mixed with the aqueous liquid.

  In this reaction, it is necessary to gently stir the alkoxysilane compound and the ammonia or amine aqueous solution layer so that the two-layer state is maintained without substantially mixing. As a result, the alkoxysilane compound in the upper layer is hydrolyzed and transferred to the lower layer, where it chemically bonds with the polyorganosiloxane particles as the base particles and grows protrusions. The reaction temperature at this time depends on the type of the alkoxysilane compound as a raw material, but is generally selected in the range of 0 to 60 ° C.

  After completion of the reaction (after the upper layer disappears), the particles are washed by centrifugation and sedimentation according to a conventional method, and then dried to form substantially spherical and / or hemispherical protrusions on the entire surface of the base particles. Silica-based fine particles are obtained.

  In the present invention, the silica-based fine particles thus obtained are composed of polyorganosiloxane having an organic group, both of the base particles and the protrusions. Therefore, if necessary, the following firing treatment can be performed. it can.

(D) Firing treatment step In this (D) step, the firing treatment is preferably performed at 500 to 1000 ° C, more preferably at 600 to 900 ° C in the presence of an oxygen-containing gas such as air, depending on the use of the final product. It may be carried out at a temperature in the range, and may be fully silicified to obtain high elastic modulus particles, or preferably in an inert gas atmosphere such as nitrogen or in vacuum, preferably 400 to 900 ° C., more preferably 500 to The low elastic modulus particles may be obtained by performing a baking treatment at a temperature in the range of 800 ° C. to perform partial silicidation or non-silicaization. That is, optimal conditions 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.
The shape of the particles thus calcined is substantially similar to that before the calcining, and has a flat sugar shape in which almost spherical or hemispherical projections are firmly bound by chemical bonds over the entire surface of the base particles. ing.

  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 the first seed particle liquid A 500 ml glass flask is set in a thermostatic water tank with a magnetic stirrer capable of adjusting temperature, and 12 ml of 1 mol / liter ammonia water and nonionic surface activity are added to this. Polyoxyethylene alkylaryl ether “Neugen EA-137 (HLB13)” [Daiichi Kogyo Seiyaku Co., Ltd.] 0.3 ml and 300 g of ion-exchanged water are added and the temperature is kept at 30 ° C. did. Next, 30 g of methyltrimethoxysilane (MTMS) is poured onto this solution so that the interface is not disturbed, and after two layers are formed, the lower aqueous ammonia solution is gently stirred with a magnetic stirrer to hydrolyze the MTMS. Reaction was performed. Over time, the lower layer ammonia aqueous solution began to become cloudy, and after 3 hours, the upper layer MTMS was transferred to the lower layer aqueous ammonia solution by hydrolysis and disappeared. In this white turbid liquid, monodisperse polymethylsilsesquioxane (PMSO) particles having an average particle diameter of 1.85 μm were generated, and this was used as a first seed particle liquid.

(2) Preparation of second seed particle liquid A 5 liter glass flask equipped with a stirring motor and a stirring blade was set in a constant temperature water bath, and 4500 ml of ion-exchanged water was put into the flask, and the above (1 The total amount of the first seed particle liquid obtained in (1) was added to dilute and disperse the seed PMSO particles. Next, 450 g of MTMS was poured into the upper layer of this dispersion, the reaction temperature was set to 30 ° C., and the hydrolysis reaction was again performed in a two-layer state to perform the growth reaction of seed PMSO particles. After 5 hours, when the upper layer MTMS disappeared, the PMSO particles grew to an average particle size of 5.0 to 5.2 μm and were monodisperse spherical particles. This was used as the second seed particle liquid.

(3) Surface treatment The polyvinyl alcohol [completely saponified type, number average molecular weight (Mn) 500] aqueous solution (PVA aqueous solution) of 1200 wt. A seed PMSO particle dispersion having a concentration of 1% by weight was prepared. Next, 15 ml of 25 wt% aqueous ammonia was added, and then the solution temperature was raised to 50 ° C. and kept at that temperature for 12 hours. The PVA-adsorbed PMSO particles (base particles) obtained here were monodispersed fine particles having an average particle diameter of 4.5 μm. Next, this was washed with methanol and dried to obtain 190 g of seed powder.

(4) Deformation treatment A 1-liter glass flask is set in a thermostatic water tank with a magnetic stirrer capable of adjusting temperature, and 2 g of the seed powder obtained in (3) above is dispersed in 800 ml of a 1% by weight PVA aqueous solution. A liquid obtained by mixing the liquid and 0.1 ml of 25% by weight aqueous ammonia was added, and the temperature was maintained at 30 ° C. Next, 70 g of methyltrimethoxysilane (MTMS) is poured onto this solution so as not to disturb the interface, and after two layers are formed, the lower aqueous ammonia solution is gently stirred with a magnetic stirrer to hydrolyze the MTMS. Reaction was performed. Over time, the lower layer aqueous ammonia solution began to become cloudy. After 2 hours, the upper layer MTMS was transferred to the lower layer aqueous ammonia solution by hydrolysis and disappeared.

As a result of taking out the particles and observing the shape with a scanning electron microscope (SEM), the entire surface of the particles had protrusions with a height of 1.4 to 3.0 μm, and the apparent average particle diameter [grains including the tip of the protrusion was included. The diameter (hereinafter referred to as the final average particle diameter)] was 6.5 μm. FIG. 1 shows a SEM photograph of this particle.
Next, the particles were washed by centrifugation and sedimentation classification, and finally dispersed in methanol. Then, the methanol was removed and dried in an oven at 120 ° C. to obtain 1.8 g of dried particles.

(5) Firing treatment After the dried particles obtained in (4) above are placed in a firing container and set in an electric furnace, air is flowed at a flow rate of 0.3 liters / minute from room temperature to 400 ° C. The temperature was raised in 25 hours, held at that temperature for 48 hours, further raised to 800 ° C. in 0.5 hours, held at that temperature for 6 hours, and then lowered to room temperature. The shape of the particles was similar to that before firing. As a result of IR measurement, no peak of the methyl group was observed, IR absorption of silica alone was recognized, and it was confirmed that the silica was changed to silica.
The dried particles were calcined at 690 ° C. for 2.5 hours or 670 ° C. for 2.5 hours while flowing nitrogen at a flow rate of 0.3 liter / min. Particles were obtained.

Example 2
The same operation as (1) to (3) in Example 1 was performed to obtain a seed powder.
(1) Deformation treatment A 1 liter glass flask was set in a thermostatic water tank equipped with a temperature-controllable magnetic stirrer, and 2 g of the above seed powder was dispersed in 800 ml of a 1% by weight PVA aqueous solution and 25% by weight. A liquid mixed with 0.1 ml of aqueous ammonia was added, and the temperature was maintained at 30 ° C. Next, 20 g of methyltrimethoxysilane (MTMS) is poured onto this solution so that the interface is not disturbed, and after two layers are formed, the lower aqueous ammonia solution is gently stirred with a magnetic stirrer to hydrolyze the MTMS. Reaction was performed.

  When the upper layer MTMS disappeared, the particles were taken out and observed by SEM. As a result, the entire surface of the particles had protrusions having a height of 0.7 to 2.0 μm and a final average particle size of 5.8 μm. It was a particle. FIG. 2 shows an SEM photograph of this particle.

Example 3
The same operation as (1) to (3) in Example 1 was performed to obtain a seed powder.
(1) Deformation treatment A 1 liter glass flask is set in a thermostatic water tank with a temperature-controllable magnetic stirrer, and 10 g of the above seed powder is dispersed in 800 ml of a 1% by weight PVA aqueous solution and 25% by weight. A liquid mixed with 0.1 ml of aqueous ammonia was added, and the temperature was maintained at 30 ° C. Next, 20 g of methyltrimethoxysilane (MTMS) is poured onto this solution so that the interface is not disturbed, and after two layers are formed, the lower aqueous ammonia solution is gently stirred with a magnetic stirrer to hydrolyze the MTMS. Reaction was performed.

  When the upper layer MTMS disappeared, the particles were taken out and observed by SEM. As a result, the entire surface of the particles had protrusions having a height of 0.2 to 1.1 μm, and the final average particle size was 5.2 μm. It was a particle. In FIG. 3, the SEM photograph figure of this particle | grain is shown.

Example 4
The same operation as (1) and (2) in Example 1 was performed to prepare a second seed particle liquid.
(1) Surface treatment In Example 1 (3), instead of using PVA with a number average molecular weight (Mn) of 500, the same procedure as in Example 1 (3) except that PVA with Mn of 1000 was used. A seed powder having an average particle size of 4.2 μm and a CV value of 1.9% was obtained.
(2) Deformation treatment MTMS hydrolysis reaction was carried out under the same conditions and in the same manner as in Example 1 (4) to obtain confetti sugar particles having protrusions on the entire surface of the particles. This particle was a confetti-like particle having protrusions having a height of 0.2 to 0.6 μm on the entire surface of the particle and having a final average particle size of 4.9 μm.

Examples 5 and 6
In Example 4, instead of PVA having a number average molecular weight (Mn) of 1000, the same procedure as in Example 4 was used except that Mn was 3500 (Example 5) and 70000 (Example 6). It was confirmed that shaped particles were obtained.

Examples 7 and 8
In Example 4, instead of PVA having a number average molecular weight (Mn) of 1000, polyvinyl pyrrolidone (PVP) having Mn of 40,000 (Example 7) and 1,200,000 (Example 8) was used. Confirmed that confetti particles were obtained by the same operation as in Example 4.

Example 9
The same operation as (1) and (2) in Example 1 was performed to prepare a second seed particle liquid.
(1) Surface treatment A 500 ml glass beaker equipped with a stirrer motor and a stirrer blade was set in a constant temperature water tank, and a polyoxyethylene alkylaryl ether [“Neugen EA-137 (HLB13)] which is a nonionic surfactant was placed in the beaker. “Daiichi Kogyo Kagaku Co., Ltd.] To the aqueous solution adjusted to 1% by weight with 1.5 g and ion-exchanged water 148.5 g, 300 ml of the second seed particle solution was added and mixed with stirring. Next, 15 ml of 25 wt% aqueous ammonia was added, and the mixture was held and stirred for 12 hours to obtain surfactant-adsorbed PMSO particles (base particles) having an average particle size of 4.7 μm and a CV value of 1.47%.
(2) Deformation treatment MTMS hydrolysis reaction was carried out under the same conditions and in the same manner as in Example 1 (4) to obtain confetti sugar particles having protrusions on the entire surface of the particles. The particles were confetti particles having protrusions with a height of 0.4 to 0.9 μm on the entire surface and a final average particle size of 5.8 μm.

Examples 10-15
In Example 9, instead of “Neugen EA-137 (HLB13)”, “Neugen EA-157 (HLB15)” which is a nonionic surfactant manufactured by Daiichi Kogyo Kagaku Co., Ltd., which is a different type of HLB (implemented) Example 10), "Neugen EA-177 (HLB17)" (Example 11), "Neugen EA-73 (HLB9)" (Example 12), "Neugen EA-143 (HLB14)" (Example 13), " Except for using "Neugen ES-149 (HLB14)" (Example 14) and "Neugen ET-147 (HLB14)" (Example 15), the same procedure as in Example 9 is used to obtain confetti particles. It was confirmed.

Example 16
In Example 9, instead of “Neugen EA-137 (HLB13)”, polyoxyethylene alkylphenyl ether “Emulgit 9 (HLB18-20)” [Daiichi Kogyo Kagaku Co., Ltd.] was used. It was confirmed that gold-peeled sugar particles were obtained in the same manner as in Example 9.

Example 17
In Example 9, instead of “Neugen EA-137 (HLB13)”, except that sodium dodecyl sulfate [SDS, HLB40, manufactured by Daiichi Kogyo Kagaku Co., Ltd.] was used, the same operation as in Example 9 was carried out. It was confirmed that confetti particles were obtained.

“Neugen EA-157” and “Neugen EA-177” are polyoxyethylene alkylaryl ethers, “Neugen EA-73” and “Neugen EA-143” are polyoxyethylene dodecyl phenyl ethers, “Neugen ES-149”. Is a polyoxyethylene oleate, and "Neugen ET-147" is a polyoxyethylene alkyl ether.

Claims (3)

(A) a step of hydrolyzing and condensing the alkoxysilane compound represented by the general formula (I) and optionally growing particles as seed particles to produce polyorganosiloxane particles;
(B) a step of surface-treating the polyorganosiloxane particles obtained in the step (A) with a surface adsorbent, and (C) the polyorganosiloxane particles surface-treated in the step (B) as seed particles, A step of forming protrusions on the entire surface of the seed particles using the alkoxysilane compound represented by the general formula (I);
A method for producing silica-based fine particles, comprising: Furthermore, (D) The method of Claim 1 including a baking process process. The method according to claim 1 or 2, wherein the surface adsorbent in the step (B) is polyvinyl alcohol, polyvinyl pyrrolidone or a surfactant.