JP4997408B2 - Hollow composite and method for producing the same - Google Patents

Description

The present invention relates to a hollow composite, hollow particles, and a method for producing the same, and more specifically, using a particulate biomaterial as a template, and forming or coating a metal compound on the surface thereof, The present invention relates to a porous hollow particle having a porous membrane structure of the metal compound and retaining the outer shape of the biomaterial, a method for producing the same, and a use as a functional member thereof. The present invention, by using a particulate biomaterial yeast particle child as a template, the shape and particle size is substantially uniform, porous hollow particles comprising a porous membrane structure holding the shell shape of the particulate biomaterials Are produced in a simple and environmentally friendly manner, and the present invention is based on the hollow structure of the porous hollow particles, so that the weight is reduced, the internal substances are released, heat insulation, etc. The present invention provides a new highly functional porous inorganic hollow particle and a functional member that exhibit the above characteristics.

  Hollow particles are characterized by having a large specific surface area for particles of the same particle size, such as lighter particle material, slow release of internal inclusion materials, optical use of internal space, low thermal conductivity of gas It is used in the field of heat insulation etc. As a method for producing the porous inorganic powder used as these hollow particles, the prior art document uses, for example, resin particles such as expanded polystyrene beads as a template, and silica, alumina, magnesia is used on the surface of the resin particles. A method has been proposed in which an inorganic powder such as dolomite is attached with a binder to form a shell made of an inorganic powder and then fired to remove resin particles (see Patent Document 1).

  In other prior art documents, resin particles serving as a template having an average particle size of about 0.8 to 100 μm and inorganic powder having an average particle size of 1/5 or less of the particles are stirred at high speed in an air stream. Then, after coating the surface of the resin particles to be a template with an inorganic powder, the resin particles are burned off (see Patent Document 2), and the surface of the resin particles to be a template is coated with a copper-based inorganic powder by high-speed stirring. (See Patent Document 3), a metal compound is added to a resin emulsion, and the metal compound is precipitated or settled on the surface of resin particles constituting the resin emulsion, and then the resin A method for producing a porous inorganic powder characterized by separating and firing the particles (see Patent Document 4) has been proposed.

  However, according to the above conventional method, the resin particles and the like are poorly dispersible in water, and surface modification such as introducing silanol groups into the resin particles in advance as a foothold for coating the coating material on the particle surface. It is pointed out that it is necessary (see Non-Patent Document 1). Further, in the above-described method, since the resin particles that can serve as a template are composed of a petroleum-based resin, consideration for the environment is required for firing.

  Furthermore, regarding the shape of the particles, particles having various shapes such as a spherical shape, a needle shape, and a spindle shape are manufactured. In the prior art documents, among these, for example, as an example of bowl-like or bowl-like particles, polymer particles that are ink jet receptor media and a method for forming the same (see Patent Document 5), a spherical shape having a bowl-like structure on the surface Ferrite carrier for electrophotographic development in which fine irregularities are formed on the surface of the crystal particles by forming a resin coating layer on the surface of the ferrite particles (see Patent Document 6) 7), polymer particles such as styrene-based polymers containing calcium phosphate (see Patent Document 8), and a method for improving the flowability of starch by the silica particles biting into the surface of the starch cake by mechanical impact (see Patent Document 9) ), Etc. have been proposed. However, any of these bowl-like materials is limited to resins and polymers.

  On the other hand, recently, as a prior art, as a biotemplate, a technique for copying DNA structure onto silica gel and semi-permanently storing DNA genetic information (see Non-Patent Document 2) and bacteria (see Non-Patent Document 3) In addition, there have been reported cases in which nanostructures are produced using chromosomes (see Non-Patent Document 4) or the like as templates.

  On the other hand, the present inventors have focused on using yeast as a biotemplate. Yeast has a cell wall mainly composed of saccharides such as β-glucan and α-mannan (see Non-Patent Document 5), is robust compared to other microorganisms such as E. coli, and is easy to handle as a template. Conceivable. As a prior art, for example, a film biodegradable sheet (see Patent Document 10), a film coating agent such as a tablet (see Patent Document 11) is prepared as an example using cell wall components of yeast particles and the structure thereof. In other cases, for example, removal by mercury adsorption for the purpose of environmental purification (see Patent Document 12), removal by adsorption of basic dye (see Patent Document 13), and the like have been attempted. However, these do not combine yeast with any effect, and are not examples of producing materials using yeast as a template.

  Furthermore, as a prior art, for example, as a case where a biological substance mainly composed of yeast and an inorganic material such as a metal oxide are combined, a metal catalyst having a metal oxide or a metal supported on the surface of a yeast cell in tobacco leaves. Composition for smoking (see Patent Document 14), for controlling the growth of microorganisms provided with a hydrophilic synthetic resin layer containing a metal oxide, a metal hydroxide, and a metal salt on the surface of a thermoplastic synthetic nonwoven fabric Materials (see Patent Document 15) have been proposed. However, the former has a metal loading of 12.5% with respect to a bread yeast diameter of 5 μm and a thickness of 31 μm. It is considered to be inferior. In the latter case, since the metal compound is blended with a hydrophilic synthetic resin such as polyvinyl alcohol, it is considered that the metal compound is not actively brought into contact with the yeast particles.

JP-A-2-277544 JP-A-5-138209 JP-A-6-39273 JP 2003-54916 A JP 2004-106517 A JP-A-11-140139 Japanese Patent Laid-Open No. 10-104884 Japanese Examined Patent Publication No. 6-37525 JP-A-4-168101 JP 2002-97301 A JP 2002-249714 A JP-A-50-051988 JP 49-021950 A Japanese Patent Laid-Open No. 51-54996 JP 2000-45166 A

Ding, X., K. Yu, Y. Jiang, H. Bala, H. Zhang and Z. Wang: “A Novel Approach to the Synthesis of Hollow Silica Nanoparticles”, Materials Letters, 58, 3618-3621 (2004) Numata, M., K. Sugiyasu, T. Hasegawa and S. Shinkai: “Sol-Gel Reaction Using DNA as a Template: An Attempt Toward Transcription of DNA into Inorganic Materials”, Angew. Chem. Int. Ed., 43, 3279-3283 (2004) Davis, S. A., S. L. Burkett, N. H. Mendelson and S. Mann: “Bacterial Templating of Ordered Macrostructures in Silica and Silica-Surfactant Mesophases”, Nature, 385, 420-423 (1997) Sugiyasu, K., S. Tamaru, M. Takeuchi, D. Berthier, I. Huc, R. Oda and S. Shinkai: “Double Helical Silica Fibrils by Sol-Gel Transcription of Chiral Aggregates of Gemini Surfactants”, Chem. Commun , 1212-1213 (2002) Hiroshi Aida et al .: “New edition of applied microbiology I”, p.85, Asakura Shoten (1981)

  In such a situation, in view of the above-described conventional technology, the present inventors proceeded with earnest research with the goal of developing new hollow particles using a biotemplate. As one of the technologies, we focused on the production of hollow particles using yeast. Yeast has been used industrially on a large scale, such as being used in the fermentation process of bread production for a long time, is easily available, and is inexpensive, and can be used as a hollow particle with a size of several microns. Appropriate. Yeast can be considered as a microcapsule that contains 70% of water in a living state and contains water necessary for hydrolysis such as alkoxide, and is more robust than other microorganisms such as Escherichia coli. It is easy to handle as a template. Furthermore, the surface is hydrophilic and does not require additional hydrophilic treatment like polystyrene latex.

The present inventors have found that the surface of the particulate biomaterial yeast particle element to produce a composite particle structure coated with a metal compound, by firing the particles, high imitation of the shape of the particulate biomaterial hollow The present invention has been completed by successfully producing porous hollow particles having a novel shape consisting of particles and hollow particles having a hollow wall having many wrinkles or a part thereof. That is, the present invention, the metal compound is added to the yeast particles child, baking was prepared by precipitation or coated with a metal compound on the surface of yeast particles child, yeast particle complexes precipitated or coated with a metal compound, the treated particles It is an object of the present invention to provide a removed hollow particle, a hollow particle having a large amount of soot, and a method for producing the same.

  Another object of the present invention is to provide micron-sized porous hollow particles having a relatively uniform particle shape and particle diameter. In addition, the present invention makes it possible to produce hollow particles that are highly imitative with the template shape by making the atmosphere to be heat-treated inactive or reducing, or by making the atmosphere oxidizable. Alternatively, it is an object of the present invention to provide a method for producing hollow particles that makes it possible to produce hollow particles having wrinkles. Further, the present invention relates to hollow particles of hollow particles whose surface chemical properties, pore structure, and crystal structure are controlled by the synthesis conditions, types, drying / firing conditions, and the like, and a method for producing the same Is intended to provide.

  Another object of the present invention is to produce and provide a composite having a biomaterial with biocompatibility inside by leaving the biomaterial in a composite comprising a particulate biomaterial and a metal compound. It is what. A further object of the present invention is to provide micron-sized porous hollow particles suitable as a particulate material used in, for example, filters, environmental purification materials, heat insulating materials, catalysts, cosmetics, paints and the like. is there.

The present invention for solving the above-described problems comprises the following technical means.
(1) Using a particulate biomaterial as a template, depositing or coating a metal compound on the surface of the biomaterial, having a porous structure of the biomaterial and the metal compound, and maintaining the outer shell shape of the biomaterial This is a method for producing porous hollow particles, in which a composite of a particulate biomaterial and a porous hollow particle is produced, and then this is heated to produce a hollow particle that does not contain the biomaterial. And
As the particulate biomaterials, using a yeast, by heating the complex in an oxidizing atmosphere, or to produce hollow particles having a wrinkled or pleated hollow wall, or, reducing the complex By performing heat treatment in an atmosphere or an inert atmosphere, producing hollow particles having an outer shell shape that is highly mimicable with a biomaterial , and in that case , performing the heat treatment at 500 to 1200 ° C. A method for producing porous hollow particles, which is characterized.
( 2 ) The method for producing porous hollow particles according to (1), wherein the metal compound is a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof.
( 3 ) The method for producing porous hollow particles according to ( 2 ), wherein the metal component of the metal compound is titanium, zirconium, aluminum, zinc, yttrium, hafnium, tin, antimony, or silicon.
(4) a multi porosifying hollow particles Rikatachi formed by the method according to any one of (1) to (3),
Or the hollow particles have a wrinkled or pleated hollow wall or hollow particles, have a shell shape is high imitation of the particulate biomaterial, the particulate biomaterial porous hollow particles but characterized that you are almost completely thermally decomposed.
( 5 ) The porous hollow particle according to ( 4 ), wherein the metal compound is a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof.
( 6 ) The porous hollow particle according to ( 5 ), wherein the metal component of the metal compound is titanium, zirconium, aluminum, zinc, yttrium, hafnium, tin, antimony, or silicon.
( 7 ) A functional member having high adsorption performance, characterized in that the porous hollow particles according to any one of ( 4 ) to ( 6 ) are used as constituent elements.
(8) members, filters, environmental purification materials, insulation, catalyst, cosmetic or functional member according to a coating composition (7).

Next, the present invention will be described in more detail.
The present invention is a hollow particle formed by depositing or coating a metal compound on the surface of a particulate biomaterial, having a porous membrane structure of the metal compound, and maintaining the outer shell shape of the biomaterial Using the point of porous hollow particles and particulate biomaterial as a template, depositing or coating a metal compound on the surface of the biomaterial, and having a porous structure of the biomaterial and the metal compound, Producing a composite of a particulate biomaterial that retains the outer shell shape and porous hollow particles, and then optionally subjecting this to heat treatment to produce hollow particles that do not contain the biomaterial , Has characteristics.

In the present invention, particulate biomaterials used as templates include 0 . Ru biomaterial der having an average particle size of 2～40Myuemu, which we yeasts. As yeast, may be used any yeast so long as it belongs to the taxonomic yeast, for example, can be cited brewer's yeast, wine yeast, baker's yeast, yeast such as torula yeast, more specifically These include Saccharomyces cerevisiae and Saccharomyces saccharomyces.
rouxii), Saccharomyces Saccharomyces
carlsbergensis), Candida utilis, Candida tropicalis, Candida lipolytica
lipolytica), Candida flaveri and the like. As yeast, it is preferable to use live yeast, but even when a yeast of a form other than live yeast, such as dry yeast, is used, for example, it can be suspended in water and treated in the same manner as live yeast.

In the present invention, the particle child-like biological materials can be used one of yeasts alone or can be used in combination and use of two or more as necessary. Although there is no restriction | limiting in particular in the shape and magnitude | size of the biomaterial to be used, As a shape, the thing of the shape close | similar to a spherical shape is preferable as possible, and the magnitude | size is preferable, for example, 0.2-40 micrometers, 1-5 micrometers The thing of the range of is more preferable.

  In the present invention, the metal compound means a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof, and there is no particular limitation on the crystallinity thereof. Any of these may be used. The metal compound to be coated is not particularly limited, but for example, one or more metal compounds selected from zinc, yttrium, aluminum, titanium, zirconium, hafnium, tin, antimony, and silicon are preferable. Specific examples of the hydroxide and oxide include zinc oxide, yttrium oxide, aluminum hydroxide, alumina, titania, zirconia, hafnium oxide, tin oxide, antimony oxide, and silica. Among these, an oxide is particularly preferable. A porous structure made of an oxide can be formed by, for example, a hydrolysis reaction, a thermal decomposition reaction, or the like of an inorganic metal salt, an organic metal salt, or a metal alkoxide. Moreover, these metal compounds can be used individually by 1 type or in combination of 2 or more types as needed.

The amount of the metal compound is not particularly limited, the kind and particle diameter of the biomaterial of the yeast particles child, the kind of the metal compound itself may be appropriately selected depending on various conditions of application of the hollow particles to be obtained, usually 1 to 100 parts by weight, preferably 5 to 50 parts by weight per 100 parts by weight of the yeast particles. As a covering surface area of the biomaterial, 1 to 100%, preferably 80 to 100%, of the material surface is covered with a metal compound. In the metal compound or a solution or dispersion is added to the biological material may be a biomaterial of the yeast particle element heated to about 15 to 95 ° C., or may not be heated.

Next, using the yeast particles as a template, the present invention will be described based on the case of using alkoxides as metal compound, in the same manner as Examples described below also using other metals compounds, the It goes without saying that the porous hollow particles of the invention can be produced, and the present invention is not limited to the following method.

  An example of the method for producing hollow particles of the present invention will be described. First, a triethanolamine as a stabilizer is mixed with an alcohol solution of a metal alkoxide and stirred at room temperature. This solution is mixed with a dispersion in which yeast particles are dispersed in water and stirred for a long time, whereby an alkoxide hydrolyzate is precipitated on the surface of the yeast particles to obtain coated yeast particles. The coated yeast particles are washed and dried, and then subjected to heat treatment at 500 to 1200 ° C. to promote crystallization of the precipitated hydrolyzate and decompose the organic matter into hollow particles. The hollow particles of the present invention are produced by a series of these steps.

  In the present invention, as described above, the reactivity of the raw material is controlled in the solution in which the yeast particles are dispersed, and the metal compound is added to the surface of the yeast particles by adding the raw material of the metal compound. For example, for a raw material having a slow reaction rate such as tetraethoxysilane, a catalyst such as ammonia is added to the solution. Conversely, for a raw material such as titanium isopropoxide having a fast reaction rate, triethanolamine (TEA ) Is previously combined with titanium isopropoxide, mixed and precipitated.

  Thus, in this invention, the reactivity of a reaction liquid can be controlled using a stabilizer. Regarding the reactivity of zirconium butoxide (ZNA), the relationship of the TEA / ZNB ratio (molar ratio) was examined. When the TEA / ZNB ratio was 0.4, when water was added to the mixed solution, precipitation immediately occurred. Because it forms, it is unsuitable for coating. Further, when the TEA / ZNB ratio is 0.6, a thin and cloudy state is obtained and precipitation is not so much observed. When the TEA / ZNB ratio is 0.8 or more, a transparent and stable solution can be obtained. Since an excessively stable solution is not suitable for the hydrolysis reaction, the TEA / ZNB ratio is suitably in the range of 0.6 to 1.

  The reaction rate of the metal compound can also be adjusted by changing the type of solution. As the solution, for example, water, alcohols, ethers, and mixtures thereof are used. It is known that when an alkoxide is used as a raw material, the reaction becomes slow when an alcohol exchange reaction such as ethanol occurs in the solution. Therefore, by using a hydrophobic organic solution such as ethanol and hexane as the solution, it is possible to deposit the metal compound uniformly on the surface of the yeast particles (see Japanese Patent Application Laid-Open No. 4-45835).

  In the present invention, the yeast particles whose surface is coated with the metal compound are separated from the reaction mixture by a general method such as filtration and centrifugation, dried as necessary, and then baked to obtain the yeast particles. Inorganic hollow particles can be produced by combustion or thermal decomposition.

  In the case where the yeast particles inside the yeast particles coated with the metal compound are burned off, the baking temperature is not particularly limited as long as the yeast particles can be thermally decomposed and burned, as shown in the thermal analysis results of FIG. However, in order to thermally decompose the yeast particles almost completely and to suppress the selection of the crystal structure of the inorganic substance and the grain growth, the firing temperature is usually 500 to 1200 ° C., particularly preferably 600 to 800 ° C. It is good. The firing time is usually 0.5 to 10 hours. In addition, in the case where the yeast particles are left and only the crystal structure of the metal compound is selected, the firing temperature is usually 200 to 800 ° C., particularly preferably 300 to 500 ° C., and the firing time is usually 0.5 to 10 hours. It is good to do.

  The crystallinity of the metal compound can be controlled by controlling the heat treatment conditions of the metal compound coated on the surface of the yeast particles. For example, when the zirconia hydrolyzate coated on the surface of the yeast particles is heat-treated, crystallization starts at around 500 ° C. from the amorphous state before the heat treatment, and crystallization into almost tetragonal crystals is completed at 700 ° C., and further 1000 ° C. Then, the transition to monoclinic crystal proceeds, and a crystal state in which tetragonal crystal and monoclinic crystal coexist is obtained. The crystallinity can be controlled by adjusting these temperatures (see FIG. 5).

  In addition, in the heat treatment in an oxidizing atmosphere, the hollow particles gradually contracted as the heat treatment temperature increased to 500 ° C. and further to 1000 ° C., and the particle size was 2 to 4 μm before the heat treatment. 1 to 2 μm. At this time, an elliptical or circular particle shape (see FIG. 3) having a relatively smooth surface before the heat treatment is transformed into a deflated shape after the heat treatment (see FIG. 6). Such a change in the shape of the particles is preferable for utilizing the zirconium hollow particles as functional particles. On the other hand, even when the coating-treated particles are heat-treated in nitrogen, for example, at 1000 ° C., it is possible to obtain hollow particles that retain the original shape with little shrinkage as particles (see FIG. 13). .

  The atmosphere at the time of firing is not particularly limited. For example, an oxidizing atmosphere such as air, a reducing atmosphere such as hydrogen gas, carbon monoxide gas and ammonia gas, an inert atmosphere such as nitrogen gas, helium gas and argon gas, etc. Can be mentioned. When calcination is performed in an oxidizing atmosphere, the yeast particles are burned out and an inorganic hollow powder is obtained. When firing in a reducing atmosphere or an inert atmosphere, composite hollow particles of yeast particles and a metal compound are obtained.

  In the present invention, the film thickness of the hollow particles can be controlled. Even if the deposition time of the zirconia film is changed under the condition of TEA / ZNB = 1, it is difficult to control the film thickness by the deposition time. Hollow particles were produced by changing the TEA / ZNB ratio, and the fracture surface was observed. When the TEA / ZNB ratio was 1, the film thickness was 0.1 μm (see FIG. 11), whereas the ratio was 0. The film thickness was 0.3 μm (see FIG. 12), and it became clear that the film thickness could be controlled by the TEA / ZNB ratio.

  The present invention, when producing hollow particles, by adjusting the reactivity by selecting raw material compounds, stabilizers, solvents, etc., formation of a uniform outer shell structure that could not be achieved conventionally, The shell film thickness can be controlled, and the crystallinity of the hollow particles and the surface shape of the outer shell structure can be controlled by adjusting the firing temperature and firing atmosphere. In addition, the micron-sized hollow particles whose properties are arbitrarily controlled as described above can be used as a highly functional material useful in various technical fields.

According to the present invention, (1) porous inorganic hollow particles with little secondary aggregation and excellent dispersibility can be easily prepared and provided. (2) Hollow particles depending on addition of raw materials and processing conditions The outer shell thickness, outer shell surface structure, pore structure, and crystal structure can be controlled. (3) Hollow particles that are highly mimicable with the template shape by controlling the atmosphere during firing Or hollow particles having many wrinkles can be prepared. (4) The hollow particles having wrinkles or wrinkles have a large area per unit volume. to the material coefficient of friction is greater since there is uneven, further, it is possible to use as the reflecting efficient material since the reflection is larger than a sphere by irregularities, by residual (5) yeast particles child, internal Can be prepared a complex between the metal compound having a yeast particle child having an affinity, (6) the hollow particles, for example, the functional fine particles constituting the cosmetic, catalyst, paint, insulation, biological materials can be used as a material, (7) do not eliminate the biological material of the yeast particles child complex features possessed by biomaterials, for example, can be suitably used as a particulate material having adsorption ability of ions or gases , The effect of.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

  In this example, zirconia hollow particles were produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast and used as a template after stirring and washing with distilled water several times. As a zirconia raw material, an 85% zirconium (IV) butoxide 1-butanol solution was used. Triethanolamine (abbreviated as TEA) was used as a stabilizer for the zirconium solution. The procedure for producing the hollow particles was as follows. First, 85% zirconium (IV) butoxide 1-butanol solution [zirconium (IV) butoxide (abbreviated as ZNB) 0.02 mol] and TEA were mixed at a predetermined ratio and stirred at room temperature for 12 hours. Thereafter, 50 ml of water was added and stirring was continued. On the other hand, 5 g of yeast was added to 150 ml of water and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate an alkoxide hydrolyzate on the yeast surface, thereby obtaining yeast particles coated with a zirconium product, which was a coating-treated yeast. The product coated yeast was washed with ethanol and water and dried at room temperature.

  The thermogravimetric analysis results of the yeast particles (a), the yeast particles (b) coated with the zirconium product, and the zirconium product alone (c) are shown in FIG. 1, and the differential thermal analysis results thereof are shown in FIG. The results in FIG. 1 are divided into two parts, a dehydration process up to 200 ° C. and a high temperature region corresponding to the subsequent combustion process of organic matter and the crystallization process of zirconia, and the water contained in the zirconia hydrolyzate. And surface hydroxyl groups are less likely to evaporate than moisture in the yeast. In addition, from the result of FIG. 2, it is recognized that the pyrolysis reaction has moved to a high temperature range of about 30 ° C. due to the presence of the coating film, such as the peak that was around 480 ° C. moved to 510 ° C. in yeast, As a result, it can be seen that heat treatment up to about 550 to 600 ° C. is necessary to eliminate the yeast-derived components as the hollow particles.

  FIG. 3 shows a scanning electron micrograph of yeast particles coated with the zirconium product. Fig. 3 shows that the coated yeast particles have a particle size of 2 to 5 μm, have an oval shape that maintains the outer shape of the outer shell of the yeast particles, a characteristic germination trace can be confirmed, and a good coating is achieved. It shows that. Although the particle | grains below 1 micron recognized by the photograph lower right are considered to be a particle | grain by zirconia aggregate, the abundance was small. In FIG. 4, the scanning electron micrograph of the zirconia hollow particle heat-processed at 700 degreeC is shown. Furthermore, the X-ray-diffraction pattern for every heat processing conditions (500 degreeC, 700 degreeC, 1000 degreeC) of the yeast particle | grains which coat | covered the zirconium product in FIG. 5 is shown. From the amorphous state before the heat treatment, crystallization started at around 500 ° C., crystallization into tetragonal crystal was completed at 700 ° C., and transition to monoclinic crystal proceeded at 1000 ° C.

  In this example, titania hollow particles were produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast and used as a template after stirring and washing with distilled water several times. Titanium isopropoxide was used as a titania raw material. Triethanolamine was used as a stabilizer for the titanium isopropoxide solution. Titanium isopropoxide 0.02 mol and TEA were mixed at a predetermined ratio and stirred at room temperature for 12 hours. Thereafter, 50 ml of water was added and stirring was continued. On the other hand, 5 g of yeast was added to 150 ml of water and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate an alkoxide hydrolyzate on the yeast surface, thereby obtaining a coated yeast. The product coated yeast was washed with ethanol and water and dried at room temperature. Furthermore, by performing heat treatment at a predetermined temperature of 500 ° C. to 1000 ° C., crystallization of titania was advanced, and the organic matter was thermally decomposed into hollow particles. The hollow particles had a bowl-like wall. FIG. 6 shows a scanning electron micrograph of hollow titania particles, and FIG. 7 shows an X-ray diffraction pattern of yeast particles coated with a titanium product. Furthermore, the transmission electron micrograph of the hollow wall of a titania hollow particle is shown in FIG. The hollow wall was composed of a few nanometer anatase microparticles, and the particles were tightly bound.

  In this example, silica hollow particles were produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast and used as a template after stirring and washing with distilled water several times. As a silica raw material, 5 ml of ethyl silicate was used. Meanwhile, 3 g of yeast was mixed with 4 g of water and 1 ml of ethanol. These two solutions were mixed, and 0.5 ml of ammonia was added as a reaction accelerator and stirred for 60 hours to precipitate an alkoxide hydrolyzate on the yeast surface, thereby obtaining a coated yeast. Furthermore, the organic substance was thermally decomposed into hollow particles by performing a heat treatment at a predetermined temperature of 500 ° C. to 1000 ° C. FIG. 9 shows a scanning electron micrograph of yeast particles coated with a silicon product.

  In this example, instead of fresh yeast of baker's yeast (Saccharomyces cerevisiae), dry beer yeast (S-23 Dried Lager Yeast; DCL Yeast LTD, UK) was used as a template to produce zirconia hollow particles. . As a zirconia raw material, an 85% zirconium (IV) butoxide 1-butanol solution was used. Further, TEA was used as a stabilizer for the zirconium solution. An 85% zirconium (IV) butoxide 1-butanol solution [ZNB 0.02 mol] and TEA were mixed at a predetermined ratio and stirred at room temperature for 12 hours. Thereafter, 50 ml of water was added and stirring was continued. On the other hand, 5 g of yeast was added to 150 ml of water and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate an alkoxide hydrolyzate on the yeast surface, thereby obtaining a coated yeast. Furthermore, the coating-treated yeast was heat-treated at 600 ° C. to obtain zirconia hollow particles. FIG. 10 shows a scanning electron micrograph of yeast particles coated with the zirconium product.

  In this example, for the purpose of controlling the film thickness of the hollow particles, coating was performed by changing the TEA / ZNB ratio. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast and used as a template after stirring and washing with distilled water several times. As a zirconia raw material, an 85% zirconium (IV) butoxide 1-butanol solution was used. Triethanolamine (abbreviated as TEA) was used as a stabilizer for the zirconium solution. Hollow particles were prepared with various TEA / ZNB ratios, and their fracture surfaces were observed. As shown in FIG. 11 and FIG. 12, when the TEA / ZNB ratio is 1, the film thickness is 0.1 μm, whereas by setting the TEA / ZNB ratio to 0.6, the film thickness becomes 0. 0. Since it increased to 3 micrometers, it turned out that film thickness control is possible by this method.

  In this example, the firing atmosphere was changed to the air and performed in a nitrogen atmosphere. When the yeast particles coated with the zirconium compound prepared in the same manner as in Example 1 were heat-treated at 1000 ° C. in nitrogen, as shown in FIG. 13, there was little shrinkage as particles and the original shape was maintained. It was found to obtain hollow particles.

  In this example, zirconia hollow particles were prepared by changing the solution to water, coating the surface of the yeast particles with a zirconium compound in ethanol, and burning the yeast particles. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast, and was used as a template after stirring and washing with distilled water and ethanol several times. As a zirconia raw material, an 85% zirconium (IV) butoxide 1-butanol solution was used. The procedure for producing the hollow particles was as follows. First, 85% zirconium (IV) butoxide 1-butanol solution [zirconium (IV) butoxide (abbreviated as ZNB) 0.02 mol] was diluted with 50 ml of ethanol and stirred at room temperature for 1 hour. Meanwhile, 5 g of yeast was added to 150 ml of ethanol and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate an alkoxide hydrolyzate on the yeast surface, thereby obtaining a coated yeast. In FIG. 14, the scanning electron micrograph of the yeast particle | grains which coat | covered the zirconium product which is the coating process particle | grains is shown. In this coated yeast, each particle was agglomerated, but the surface of the yeast was coated with a zirconium product. The hollow wall structure was relatively sparse with pores between the particles.

As described above in detail, the present invention relates to porous inorganic hollow particles having an outer shell structure made of a metal compound, a method for producing the same, and a functional member. According to the present invention, a particulate biomaterial is used as a template. By using it, it is possible to easily produce and provide porous, hollow particles having a relatively uniform particle shape and particle diameter in an environmentally friendly manner. In the present invention, the hollow powder having a new soot has a larger area per unit volume than that of a normal hollow powder, and therefore has an effect such as adsorption. In addition, since the powder surface has irregularities also in terms of its shape, it can be used as a powder having a large friction coefficient. Furthermore, it can be used as a powder having higher reflection efficiency than a sphere due to its wrinkles from the optical aspect. Further, in the present invention, the complex not lost a template consisting of biomaterial yeast particles child has a biomaterial yeast particles child, for example, a feature such as the adsorption capacity of the ion or gas, out of the porous It can be used as a new composite material with high functionality combining the characteristics of the shell structure. The porous hollow particles of the present invention include, for example, adsorbents, ion exchange materials, separation materials, hazardous substance treatment materials, electrode materials, dielectric materials, pigments and cosmetics, catalysts, paints, heat insulating materials, environmental purification members, etc. In the field, it can be suitably used as a fine particle material having high functionality.

The results of thermogravimetric analysis of the yeast particles (a), the yeast particles (b) coated with the zirconium product produced in Example 1, and the zirconium products (c) are shown. The results of differential thermal analysis of yeast particles (a), yeast particles (b) coated with the zirconium product prepared in Example 1, and zirconium products (c) are shown. The scanning electron micrograph of the yeast particle | grains which coat | covered the zirconium product produced in Example 1 is shown. The scanning electron micrograph of the zirconia hollow particle produced by heat-processing at 700 degreeC in Example 1 is shown. The X-ray-diffraction pattern for every heat processing conditions (Before heat processing, 500 degreeC, 700 degreeC, 1000 degreeC) of the yeast particle | grains coat | covered with the zirconium product produced in Example 1 is shown. The scanning electron micrograph of the titania hollow particle which has the hook shape produced in Example 2 is shown. The X-ray-diffraction pattern for every heat processing conditions (Before heat processing, 500 degreeC, 700 degreeC, 1000 degreeC) of the yeast particle | grains coat | covered with the titanium product produced in Example 2 is shown. The transmission electron micrograph of the hollow wall of the titania hollow particle produced in Example 2 is shown. The scanning electron micrograph of the yeast particle | grains which coat | covered the silicon product produced in Example 3 is shown. The scanning electron micrograph of the zirconia hollow particle which coat | covered the zirconium product produced in Example 4 is shown. The scanning electron micrograph of a 0.1-micrometer-thick zirconia hollow particle cross section produced in Example 5 is shown. (The ratio of zirconium (IV) butoxide to triethanolamine is 1: 1) The scanning electron micrograph of the cross section of the zirconia hollow particle with a film thickness of 0.3 micrometer produced in Example 5 is shown. (The ratio of zirconium (IV) butoxide to triethanolamine is 1 to 0.6) The scanning electron micrograph of the zirconia hollow particle produced in Example 6 by heat-processing in 1000 degreeC and nitrogen atmosphere is shown. In Example 7, the scanning electron micrograph of the yeast particle which coat | covered the zirconium product produced in ethanol is shown.

Claims (8)

Using a particulate biomaterial as a template, depositing or coating a metal compound on the surface of the biomaterial, having a porous structure of the biomaterial and the metal compound, and maintaining the outer shell shape of the biomaterial A method for producing a porous hollow particle, in which a composite of a particulate biomaterial and a porous hollow particle is produced, and then this is heated to produce a hollow particle that does not contain the biomaterial,
As the particulate biomaterials, using a yeast, by heating the complex in an oxidizing atmosphere, or to produce hollow particles having a wrinkled or pleated hollow wall, or, reducing the complex By performing heat treatment in an atmosphere or an inert atmosphere, producing hollow particles having an outer shell shape that is highly mimicable with a biomaterial , and in that case , performing the heat treatment at 500 to 1200 ° C. A method for producing porous hollow particles, which is characterized.   The method for producing porous hollow particles according to claim 1, wherein the metal compound is a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof. The method for producing porous hollow particles according to claim 2 , wherein the metal component of the metal compound is titanium, zirconium, aluminum, zinc, yttrium, hafnium, tin, antimony, or silicon. A multi porosifying hollow particles Rikatachi formed by the method according to any one of claims 1 to 3,
Or the hollow particles have a wrinkled or pleated hollow wall or hollow particles, have a shell shape is high imitation of the particulate biomaterial, the particulate biomaterial porous hollow particles but characterized that you are almost completely thermally decomposed. The porous hollow particle according to claim 4 , wherein the metal compound is a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof. The porous hollow particle according to claim 5 , wherein the metal component of the metal compound is titanium, zirconium, aluminum, zinc, yttrium, hafnium, tin, antimony, or silicon. Functional member having a high adsorption performance, characterized in that a component porous hollow particles according to any of claims 4 to 6. The functional member according to claim 7 , wherein the member is a filter, an environmental purification material, a heat insulating material, a catalyst, a cosmetic, or a paint.