JPH038729A - Production of porous glass - Google Patents

Abstract

PURPOSE:To obtain porous glass having small pore diameter by subjecting metallic alkoxide to hydrolysis and polymerization in a reacting solution containing said alkoxide, etc., and organic polymer such as polyacrylic acid, etc., and burning resultant gel. CONSTITUTION:An organic polymer such as polystyrene sodium sulfonate, polyacrylic acid or polyallylamine is prepared. Then, a reacting solution containing metallic alkoxide or oligomer of said alkoxide and said organic polymer is prepared. Said metallic alkoxide or oligomer of said alkoxide is subjected to hydrolysis and polymerization in said solution to form a gel. Next, resultant gel is burned to afford porous glass containing pores having uniform diameter in a range of micron-order.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a porous material that can be used in a wide range of applications where pores on the order of submicrons to microns are required, such as catalyst carriers, enzyme carriers, and separation membrane materials. The present invention relates to a method for producing quality glass by a sol-gel method.

[Prior art] Among conventional porous ceramics, those with ultrafine pore diameters of submicrons or less mainly utilize the phase separation phenomenon caused by heat treatment of borosilicate glass to form an entangled phase separation structure. It is made by eluting one phase with acid.

On the other hand, those with pore diameters of microns or more are made by calcining and thermally decomposing ceramic raw material powder to create particles or open pores between particles, and then sintering under appropriate conditions. However, with these methods, it is difficult to produce porous ceramics with uniform pore diameters ranging from submicrons to several tens of microns. Furthermore, there is a drawback that it is difficult to produce ceramics in the form of membranes or fibers required depending on the application.For this reason, metal alkoxides, which can be used to produce ceramics in any shape, such as bulk, membrane, or fibers, have recently been developed. The sol-gel method using as a raw material has come to be applied to the production of porous ceramics.

However, the porous gel body produced by the above method in which silicon alkoxide is hydrolyzed and polymerized in an organic solvent such as alcohol to gel the reaction solution system, and then the resulting porous gel is fired. The pore diameter is extremely small, several tens of nanometers or less. Therefore, attempts have been made to add a large amount of hydrochloric acid for hydrolysis in order to make the pores on the micron order, but this has the problem of widening the pore size distribution.

Further, JP-A-62-123032 discloses a method for producing porous glass by adding a polyvinyl acetate emulsion to a silicon ethoxide sol solution, mixing the mixture, gelling it, and firing it. However, there is a problem in that the pore size distribution of porous glass produced by such a method is wide.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the above-mentioned problems that the prior art had, and to provide a manufacturing method capable of producing a porous ceramic whose pore diameter is on the order of microns and whose pore diameter distribution is narrow. shall be.

[Means for Solving the Problems] The present invention involves preparing a reaction solution containing a metal alkoxide or its oligomer and an organic polymer, and hydrolyzing and polymerizing the metal alkoxide or its oligomer in the solution to form a gel. A method of producing porous glass by preparing a gel and firing the gel, wherein the organic polymer is compatible with a solution of the metal alkoxide or its oligomer, and the organic polymer is compatible with the solution of the metal alkoxide or its oligomer.
The present invention provides a method for producing porous glass that causes phase separation and substantially no precipitation during the polymerization process.

The present invention utilizes the phenomenon in which a uniformly dissolved organic polymer undergoes phase separation during the hydrolysis/polymerization process of a metal alkoxide or its oligomer. As such an organic polymer, one is used that has compatibility to dissolve uniformly in a solution generated by hydrolysis of a metal alkoxide or its oligomer, causes phase separation during the hydrolysis process, and does not cause precipitation. Ru.

Examples of organic polymers having such characteristics include water-soluble organic polymers that can be made into an aqueous solution of an appropriate concentration, and are alcohol-containing liquids that are generated by hydrolysis of alkoxides or oligomers thereof, which are generated by hydrolysis of metal alkoxides or oligomers thereof. Any material that can be uniformly dissolved in the water may be used. Specifically, sodium salt of polystyrene sulfonic acid, which is a polymeric metal salt, polyacrylic acid, which is a polymeric acid that dissociates to form a polyanion, and polyallylamine and polyethylene, which are polymeric bases that produce polycation in an aqueous solution. Suitable examples include imine, etc., or polyvinylpyrrolidone, which is a neutral polymer and has a γ-lactam in its side chain, such as polyethylene oxide, which has an ether bond in its main chain.

As the metal alkoxide or its oligomer, those having a small number of carbon atoms such as methoxy group, ethoxy group, propoxy group, etc. are preferable. Further, as the metal, the metal of the oxide that is finally formed, such as Si, Ti, Zr, and Al, is used. This metal may be one type or two or more types.

On the other hand, the oligomer may be one that can be uniformly dissolved in alcohol (specifically, it can be used up to the level of 10-mer). 0.03-0.4
It is preferable to mix at a ratio of 0 parts by weight.

If the amount of the organic polymer is greater than the above range, it is unfavorable in the following respects. That is, during gelation, the SiO2 polymer phase does not form a continuous skeleton and is precipitated in the form of particles. On the other hand, if the amount of the organic polymer is is less than the above range, the organic polymer phase and the silica polymer phase will not gel in an entangled state, making it impossible to form a porous body with continuous through-holes of uniform pore size. Mixing with the oligomer is not particularly limited, but it can be achieved by dissolving the organic polymer in an acidic aqueous solution and stirring this solution and the metal alkoxide or its oligomer. The organic polymer may be added after mixing with the oligomer, or the organic polymer may be added after the metal alkoxide or its oligomer is partially hydrolyzed and polymerized.In this case, the acidic aqueous solution used is is usually preferably a mineral acid of 0.001N or higher, such as hydrochloric acid or nitric acid.In addition, when tetramethoxysilane or its oligomer is used, if it is hydrolyzed using an aqueous solution containing no acid,
Porous glass with high strength can be obtained. For hydrolysis, the solution is placed in a closed container and kept at room temperature 4.
This is achieved by holding at 0-80°C for 0.5-5 hours. Hydrolysis Decomposition involves a process in which an initially transparent solution becomes cloudy, undergoes phase separation with the organic polymer, and finally gels.

During this hydrolysis process, the organic polymer or its polymer is in a dispersed state and substantially no precipitation occurs.

The thus gelled product is aged by leaving it at 40-80°C for several hours to several tens of hours, then washed with water to remove organic polymers, and fired at about 800-1000°C to form porous glass. get.

The pore structure of the object of the present invention depends on the temperature and pH of the reaction system.
value, the molecular weight and storage capacity of the organic polymer, and various other conditions that affect the reactivity of the metal alkoxide or its oligomer and the solubility of the coexisting organic polymer. Therefore, although it is difficult to uniformly describe the method for controlling the pore three-dimensional structure, as long as the above-mentioned conditions are the same, it is possible to provide a target product with substantially the same pore diameter etc. with good reproducibility.

Although it is possible to use the porous gel produced as an intermediate substance as it is, its use is limited because it swells in water and has low mechanical strength.

If the porous gel described above is fired, it becomes SiO□-based porous ceramics with improved mechanical strength. However, if it is fired without removing the organic polymer, it may decompose depending on the type of organic polymer. The substance produced is SiO
This creates problems such as hindering the vitrification of □.

Organic polymers can be removed to some extent from the porous gel produced as an intermediate by washing the gel with water before drying, but the organic polymers may further decompose or burn after the washing process. It is advantageous to heat the gel for a long enough period of time to remove it completely.

[Example] The present invention will be explained in detail below.

Example 1: When polystyrene sulfonic acid is used as an organic polymer Example 1-1 First, polystyrene sulfonate-1), which is a polymeric metal salt, is
It was dissolved in 5.51 g of 1N nitric acid aqueous solution to make a 20% by weight solution. After adding 5 mQ of methanol to make a homogeneous solution, 5 mQ of tetramethoxysilane was added dropwise over about 1 minute to carry out a hydrolysis reaction. After stirring for several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 40°C, whereupon it solidified after about 20 hours. The solidified sample was further aged for several days, dried at 60°C, and then heated to 500°C at a temperature increase rate of 100°C/h. Wash the decomposition products of sodium polystyrene sulfonate with distilled water, and finally
Heat treatment was performed at 00°C for 2 hours. In the obtained porous silica glass, uniform pores of about 5 μm existed in an entangled structure. Note that the microstructure and pore diameter of the sample dried at 60° C. almost matched those of the porous silica glass after heat treatment.

Example 1-2 Sodium polystyrene sulfonate hydrolysis was carried out in the same manner as in Example 1, except that 5 mQ of methanol was not added. Thereafter, the holding conditions were changed to within 10 hours at 25°C in a closed container, and the solidified sample was aged, dried, heated, washed, and heat treated under the same conditions as in Example 1-1 to reduce the pore diameter of the porous glass to approximately 1 μm. could be controlled.

Example 1-3 Sodium polystyrene sulfonate was dissolved in 5.51 g of a 1N nitric acid aqueous solution to make a 33% by weight solution. After adding 5n+Q of methanol to this, 5mQ of tetramethoxysilane was added dropwise over about 1 minute to carry out a hydrolysis reaction. After stirring for several minutes, the resulting clear solution was transferred to a sealed container and kept in a constant temperature bath at 40°C, whereupon it was assimilated after about 20 hours. The solidified sample was aged, dried, heated, washed, and heat treated under the same conditions as in Example 1-1 to obtain porous silica glass having an agglomerated structure of spherical particles of about 3 μm.

Example 1-4 Sodium polystyrene sulfonate with a clear molecular weight range (P'SL manufactured by Tosoh, molecular weight 10,000 to 30,000) was dissolved in 5.51 g of lN nitric acid aqueous solution to give a solution of 24.1 weight % and tetramethoxysilane 5% was added to this solution under stirring.
A hydrolysis reaction was carried out by adding mQ dropwise. After stirring for several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 40°C, whereupon it solidified within about 2 hours. Prior to drying, the solidified sample was immersed in an aqueous 1N nitric acid solution and washed out of the solidified sodium polystyrene sulfonate. The sample, which was then dried at 60°C, was porous and had a structure in which pores with a tol diameter of about 1 μm were intertwined.

This sample was further heated to 900°C at a heating rate of 100'C/h.
Porous silica glass with a structure similar to that of Habo was obtained.

Example 1-5 Sodium polystyrene sulfonate with a clear molecular weight range (manufactured by Tosoh, Psi, molecular weight 10,000 to 30,000) was dissolved in 5.51 g of lN nitric acid aqueous solution to give a concentration of 25.0% by weight. and add 55% of tetramethoxysilane to this solution while stirring.
A hydrolysis reaction was carried out by adding mQ dropwise. After stirring for several minutes, the resulting transparent solution was transferred to a closed container and kept in a constant temperature bath at 60° C., whereupon it solidified within about 1 hour. Prior to drying, the solidified sample was immersed in a 1N aqueous nitric acid solution, and the solidified material, which was sodium polystyrene sulfonate, was washed out. The sample, which was then dried at 60°C, was porous and had a structure in which pores with a diameter of about 0.3 μm were intertwined. In addition, the concentration of sodium polystyrene sulfonate was 27.
By increasing the pore size to 5% by weight, the pore size is approximately 20 μm.
could be controlled continuously. By subjecting the dried sample to a predetermined heat treatment, porous silica glass with a structure similar to that of Habo was obtained.

Example 1-6 Sodium polystyrene sulfonate with a clear molecular weight range (manufactured by Kik Tosoh, PS5. molecular weight 50,000 to 10,000)
was dissolved in 5.51 g of 1N nitric acid aqueous solution to obtain 19.1
After adjusting the weight percentage, 5 mQ of tetramethoxysilane was added dropwise to this solution under stirring to perform a hydrolysis reaction. After stirring for several minutes, the resulting transparent solution was transferred to a closed container and kept in a constant temperature bath at 40° C., whereupon it solidified within about 2 hours. Prior to drying, the solidified sample was immersed in a 1N aqueous nitric acid solution to wash out decomposition products of sodium polystyrene sulfonate from the solidified body. The sample was then dried at 60°C.
It was porous and had an entangled structure with pores having a diameter of about 50 μm.

In addition, the concentration of sodium polystyrene sulfonate was increased to 16
．． By reducing the amount to 6% by weight, the pore size could be continuously controlled to about 0.3 μm. Similarly, by fixing the amount of sodium polystyrene sulfonate added and increasing the amount of 1N nitric acid aqueous solution to 6.17 g, the pore diameter could be continuously controlled to about 0.1 tLm. By subjecting the dried sample to a prescribed heat treatment, porous silica glass with almost the same structure was obtained.

In addition, 1.20 g of sodium polystyrene sulfonate,
lNitric acid aqueous solution 5.51g, tetramethoxysilane 5
The pore size distribution measured by the mercury pressure method for a porous glass prepared from a solution consisting of 1 ml is shown in Fig. 1 by marks.

Example 1-7 Sodium polystyrene sulfonate with a clear molecular weight range (PS5, manufactured by Tosoh, molecular weight 50,000 to 100,000) was dissolved in 5.51 g of lN nitric acid aqueous solution to give a concentration of 19.1% by weight. , tetramethoxysilane 5 was added to this solution under stirring.
A hydrolysis reaction was carried out by adding mQ dropwise. After stirring for several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 60°C, whereupon it solidified within about 1 hour. Prior to drying, the solidified sample was immersed in a 1 N nitric acid aqueous solution to wash out sodium polystyrene sulfonate from the solidified body. The sample, which was then dried at 60° C., was porous and had a structure in which pores with a diameter of about 0.5 μm were intertwined. In addition, the concentration of sodium polystyrene sulfonate was 21.4
By increasing the pore size to about 20 μm by weight%
could be controlled continuously. Similarly, the amount of sodium polystyrene sulfonate added was fixed, and the amount of 1N nitric acid aqueous solution was adjusted to 5. (By reducing the pore size to 17 g, we were able to continuously control the pore diameter to about 20 μm. By subjecting the dried sample to a prescribed heat treatment,
Porous silica glass with a structure similar to that of Habo was obtained.

Example 1-8 Sodium polystyrene sulfonate with a clear molecular weight range (■ Tosoh, PS50, molecular weight 400,000 to 600,000) was dissolved in 5.51 g of lN nitric acid aqueous solution, and 14.
0% by weight, and 5 m (2) of tetramethoxysilane was added dropwise to this solution while stirring to perform a hydrolysis reaction. After stirring for several minutes, the resulting transparent solution was transferred to a sealed container and placed in a constant temperature bath at 40°C. It solidified within about 2 hours when kept at 60°C.Prior to drying, the solidified sample was immersed in a 1N nitric acid aqueous solution to wash out sodium polystyrene sulfonate from the assimilate.After this, the sample was dried at 60°C. 0.3μm
It was porous, consisting of an intertwined structure with pores of approximately In addition, the concentration of sodium polystyrene sulfonate was increased to 1
When the concentration was 3.2% by weight and 1 ml of methanol was allowed to coexist during the reaction, the pore size was about 0.5 μm. By subjecting the dried sample to a predetermined heat treatment, porous silica glass with a structure similar to that of Habo was obtained.

Example 1-9 Sodium polystyrene sulfonate with a clear molecular weight range (manufactured by Kik Tosoh, PS5, molecular weight 5 to 100,000) was dissolved in 9.36 g of a 1 N nitric acid aqueous solution to give a concentration of 11.4% by weight. , tetraethoxysilane 7 was added to this solution under stirring.
A hydrolysis reaction was carried out by adding mQ dropwise. After stirring for several minutes, the resulting transparent solution was transferred to a closed container and kept in a constant temperature bath at 60° C., whereupon it solidified within about 2 hours. Prior to drying, the solidified sample was immersed in a 1N aqueous nitric acid solution to wash out sodium polystyrene sulfonate from the assimilate. The sample, which was then dried at 60° C., had a porous structure with entangled pores of about 2 μm in diameter. Furthermore, by changing the concentration of sodium polystyrene sulfonate from 10.5% by weight to 11.8% by weight, the pore diameter could be continuously controlled from about 0.3 μm to about 15 μm. Similarly, the amount of sodium polystyrene sulfonate added is fixed, and the amount of ■ normal nitric acid aqueous solution is 9.
By changing from 64 g to 9.09 g, the pore size could be continuously controlled from about 0.5 μm to about 50 μm. Furthermore, by changing the reaction temperature from 40°C to 80°C, the pore diameter can be reduced from less than 1 μm to several tens of μm.
It was possible to control up to m. By subjecting the dried sample to a predetermined heat treatment, porous silica glass with a structure similar to that of Habo was obtained.

Example 2: When using polyacrylic acid as an organic polymer Example 2-1 First, a 25% by weight aqueous solution of polyacrylic acid, which is a polymeric acid (Product No. 19205-8 manufactured by Aldrich, molecular weight 90,000), was dissolved in distilled water. It was diluted to make a 7.4% aqueous solution, and concentrated nitric acid was added to this to make it acidic with 1N nitric acid. 5.19g of this solution
7 mQ of tetraethoxysilane was added to the mixture under stirring to carry out a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 60°C, whereupon it solidified after about 2 hours. The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then dried at 60°C. The dried sample had a tangled structure of uniform pores of about 3 μm.

In addition, in FIG. 2, the pore size distribution measured by the mercury intrusion method is shown by marks. When ethanol was added to the reaction solution up to a maximum of 5 mQ and solidified, the pore diameter of the resulting porous body became smaller, and this could be continuously controlled to a minimum of about 0.5 μm. In addition, the amount of the 1N nitric acid aqueous solution used was varied from a minimum of 3.3 g to a maximum of 16.5 g, and the pore diameter of the resulting porous body was varied from a maximum of approximately 20 μm to a minimum of 0.0 μm.
It was possible to control within a range of 5LLm. Furthermore, the pore diameter could be similarly controlled by changing the concentration of polyacrylic acid and the reaction temperature. 1 of these dried samples
When heated to 900°C at a heating rate of 00°C/h and held at this temperature for 2 hours, porous silica glass having almost the same structure was obtained.

Example 2-2 First, a 25% by weight aqueous solution of polyacrylic acid, which is a polymeric acid (product number 19205-8 manufactured by Aldrich).

(molecular weight 90,000) was diluted with distilled water to make a 7.4% aqueous solution, and then concentrated nitric acid was added to make the solution acidic with 1N nitric acid. To this solution consisting of 0.4 g of polyacrylic acid and 5.51 g of 1N nitric acid, 5 mQ of tetramethoxysilane was added under stirring to carry out a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 60°C, whereupon it solidified after about 2 hours. The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then dried at 60°C. The dried sample had a skeleton of about 300 μm and an entangled structure containing minute pores within the skeleton. When methanol is added to the above reaction solution up to a maximum of 5 mQ and solidified, the pore diameter of the resulting porous material becomes small, and the pore size of the obtained porous material becomes smaller, with a minimum of 10 mQ.
This could be continuously controlled down to about μm. Furthermore, when the amount of 1N nitric acid aqueous solution was increased to a maximum of 11 g without adding methanol, the pore diameter could be continuously controlled to a minimum of about 30 μm.

By subjecting these dried samples to a prescribed heat treatment, porous silica glass having almost the same structure was obtained.

Example 2-3 First, polyacrylic acid (product number 18128-5 manufactured by Aldrich, molecular weight 250,000), which is a high molecular acid, was dissolved in 5.51 g of a 1N nitric acid aqueous solution to give a concentration of 3.50% by weight. 7 mQ of tetraethoxysilane was added to this solution under stirring to carry out a hydrolysis reaction. After a few minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 80°C.
It solidified after some time. The solidified sample was further aged for several hours,
After washing several times with distilled water and ethanol, it was dried at 60°C. The dried sample had a skeleton of approximately 30 μm and an entangled structure containing minute pores within the skeleton. When ethanol is added to the above reaction solution up to a maximum of 5 mQ and solidified, the pore diameter of the resulting porous material becomes small and the minimum l
This could be continuously controlled to about 0 μm.

Furthermore, when the amount of 1N nitric acid aqueous solution was increased to a maximum of 11 g without adding ethanol, the pore diameter could be continuously controlled to a minimum of about 10 μm. Furthermore, the pore diameter could be similarly controlled by changing the concentration of polyacrylic acid and the reaction temperature. By subjecting these dried samples to a prescribed heat treatment, porous silica glass having almost the same structure was obtained.

Example 2-4 First, polyacrylic acid (product number 18128-5 manufactured by Aldrich, molecular weight 250,000), which is a high molecular acid, was added to 5.5 liters of distilled water.
It was dissolved in 0g to give a concentration of 7.4% by weight. A hydrolysis reaction was carried out by adding 5 mQ of tetramethoxysilane to this solution with stirring without adding an acid as a hydrolysis catalyst. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 60°C, whereupon it solidified after about 1 hour. After the solidified sample was further aged for several hours and washed several times with distilled water and ethanol,
It was dried at 60°C. In the dried sample, pores of approximately 0.5 μm were present in an entangled structure. When methanol is added to the above reaction solution up to a maximum of 2 mQ and solidified, the pore diameter of the resulting porous material becomes small (minimum 0.2 mQ).
This could be continuously controlled down to about μm. In addition, when the amount of distilled water is changed from a minimum of 4.0 g to a maximum of 6.0 g without adding methanol, the pore size can be increased to a maximum of 5 μm.
It was possible to continuously control the thickness from 0.1 μm to a minimum of about 0.1 μm. Furthermore, the pore diameter could be similarly controlled by changing the concentration of polyacrylic acid and the reaction temperature. By performing prescribed heat treatment on these dried samples,
Porous silica glass with almost the same structure was obtained.

Example 2-5 First, polyacrylic acid (product number 18128-5 manufactured by Aldrich, molecular weight 250,000), which is a high molecular acid, was dissolved in 5.51 g of 1N nitric acid to give a concentration of 3.50% by weight.

5.15 g of tetramethoxysilane and 0.515 g of titanium tetrabutoxide (butyl orthotitanate), which had been mixed and dissolved in advance, were added to this solution under stirring to carry out a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 40°C, whereupon it solidified after about 1 hour.

The solidified sample was further aged for several hours, washed several times with 1N nitric acid and ethanol, and then dried at 60°C. In the dried sample, pores of approximately 1 μm were present in an entangled structure. When the dried sample was further heated at a heating rate of 100°C/'h and held at 800°C for 1 hour, it was found that silica-titania had almost the same structure and no microcrystal precipitation was observed by X-ray diffraction. A porous glass was obtained.

Example 3: When using polyethylene oxide (polyethylene glycol) as the organic polymer Example 3-1 First, polyethylene oxide (product number 1819g-6 manufactured by Aldrich: molecular weight 100,000), which is a neutral polymer, was
13.1% by weight when dissolved in 6.61g of 1N nitric acid aqueous solution
And so. Add 7ml of tetraethoxysilane to this solution while stirring.
Q was added to carry out a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 40°C, whereupon it solidified after about 8 hours. The solidified sample was further aged for several hours and washed several times with distilled water and ethanol.
Dry at °C. The dried sample had a tangled structure of uniform pores of about 3 μm.

Reduce the concentration of polyethylene glycol in the above reaction solution to a minimum of 1
When changing from 2.6% by weight to 14.3% by weight,
The pore diameter could be continuously controlled from a maximum of 6 μm to a minimum of about 0.5 μm. Furthermore, the pore diameter could be similarly controlled by changing the concentrations of 1N nitric acid aqueous solution and ethanol, and the reaction temperature. These dried samples
When heated to 900° C. at a heating rate of 100”C/h and held at this temperature for 2 hours, porous silica glass having a similar structure was obtained.

Example 3-2 First, polyethylene oxide (product number 18199-4 manufactured by Aldrich, molecular weight 200,000), which is a neutral polymer, was
■Normal nitric acid aqueous solution e, dissolved in 6tg, 13.1% by weight
And so. Add 7ml of tetraethoxysilane to this solution while stirring.
Q was added to carry out a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 40°C, whereupon it solidified after about 8 hours. The solidified sample was further aged for several hours and washed several times with distilled water and ethanol.
Dry at °C. In the dried sample, pores of approximately 1 μm were present in an entangled structure.

The pore diameter could be controlled by changing the concentrations of polyethylene glycol, 1N nitric acid aqueous solution, and ethanol in the reaction solution, and the reaction temperature. By subjecting these dried samples to a predetermined heat treatment, porous silica glass having a structure similar to that of Habo was obtained.

Example 3-3 First, a neutral polymer, polyethylene glycol (Wako Tsumugi Kogyo Co., Ltd. (Kiyomi product number 16812221: molecular weight 40,000 to 60,000), was dissolved in 6.61 g of lN nitric acid aqueous solution.
The content was 2.6% by weight. 7 mQ of tetraethoxysilane was added to this solution under stirring to carry out a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 40°C, whereupon it solidified after about 8 hours. The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then dried at 60°C. In the dried sample, pores of approximately 2 μm in size were present in an entangled structure. The pore diameter could be controlled by changing the concentrations of polyethylene glycol, 1N nitric acid aqueous solution, and ethanol in the reaction solution, and the reaction temperature. By subjecting these dried samples to a predetermined heat treatment, porous silica glass having a structure similar to that of Habo was obtained.

Example 3-4 First, polyethylene glycol (manufactured by Hayashi Pure Chemical Industries, Ltd.: molecular weight 20,000), which is a neutral polymer, was added to a 6.61 liter aqueous solution of nitric acid.
g to obtain a 12.0% by weight aqueous solution. To this solution, 7 m (2 m) of tetraethoxysilane was added under stirring to perform a hydrolysis reaction.After a few minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 40°C for about 8 hours. After that, it solidified.The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then dried at 60°C.The dried sample had an entangled structure of uniform pores of about 1 μm. The pore diameter could be controlled by changing the concentrations of polyethylene glycol, normal nitric acid aqueous solution, and ethanol in the reaction solution, as well as the reaction temperature.

By subjecting these dried samples to a predetermined heat treatment, porous silica glass having a structure similar to that of Habo was obtained.

Example 3-5 First, a neutral polymer, polyethylene glycol (manufactured by Hayashi Pure Chemical Industries, Ltd., molecular weight: 6,000), was added to a 1N aqueous nitric acid solution of 6.
It was dissolved in 16 g to make a 7.03% by weight aqueous solution. 7 mQ of tetraethoxysilane was added to this solution under stirring to carry out a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 40°C, whereupon it solidified after about 8 hours. The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then dried at 60°C. In the dried sample, pores of approximately 1 μm were present in an entangled structure. The pore diameter could be controlled by changing the concentrations of polyethylene glycol, 1N nitric acid aqueous solution, and ethanol in the reaction solution, and the reaction temperature.

By subjecting these dried samples to a predetermined heat treatment, porous silica glass having a structure similar to that of Habo was obtained.

Example 4: When polyvinylpyrrolidone is used as an organic polymer Example 4-1 First, polyvinylpyrrolidone (product number 85645-2 manufactured by Aldrich, molecular weight 10,000), which is a neutral polymer, is
It was dissolved in 5.51 g of normal nitric acid aqueous solution to give a concentration of 21.4% by weight. Add 5 m of tetramethoxysilane (
2 was added to perform a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 60°C, whereupon it solidified after about 1 hour. The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then
It was dried at 0°C. The dried sample had a tangled structure of uniform pores of about 3 μm.

By changing the concentration of polymer in the reaction solution and the reaction temperature, porous bodies with different pore sizes were obtained. These dried samples were heated to 900 °C at a heating rate of 100 °C/h.
When heated to °C and held at this temperature for 2 hours, porous silica glass having a structure similar to that of Habo was obtained.

Example 4-2 First, polyvinylpyrrolidone (product number 85656-g manufactured by Aldrich, molecular weight N40,000), which is a neutral polymer, was dissolved in 5.0 g of distilled water to give a concentration of 23.1% by weight. 5 m (2) of tetramethoxysilane was added to this solution with stirring to perform a hydrolysis reaction. After a few minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 60°C, and within about 30 minutes. The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then dried at 60°C. The sample had a tangled structure of uniform pores of about 0.043 μm. Figure 3 shows the pore size distribution measured by mercury intrusion porosimetry.By changing the concentration of polymer in the reaction solution and the reaction temperature, porous bodies with different pore sizes were obtained.

By subjecting these dried samples to a predetermined heat treatment, porous silica glass having a structure similar to that of Habo was obtained.

Example 5: When using polyallylamine as an organic polymer Example 5-1 First, polyallylamine having only a primary amine in the side chain (
Nittobo PAA-1 (CL-L: molecular weight 8000~
11000) in a 0.5 N nitric acid aqueous solution and
The content was 1.8% by weight. 5 mQ of tetramethoxysilane was added to 10.51 g of this solution under stirring to carry out a hydrolysis reaction. After a few minutes, transfer the resulting clear solution to a sealed container.
When kept in a constant temperature bath at 40°C, it solidified within about 2 hours. The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then dried at 60°C. The dried sample had a tangled structure of uniform pores of about 3 μm. By changing the concentration of polymer in the reaction solution and the reaction temperature, porous bodies with different pore sizes were obtained. When these dried samples were heated to 900° C. at a heating rate of 100° C./h and held at this temperature for 2 hours, porous silica glass having a similar structure was obtained.

Example 5-2 First, polyallylamine hydrochloride having only a primary amine in the side chain (PAA-HCL-H manufactured by Nittobo Co., Ltd.: molecular weight 500
00-65000) was dissolved in a 0.5 N nitric acid aqueous solution to give a concentration of 3.67% by weight. 3 m (2) of tetramethoxysilane was added to 10.51 g of this solution under stirring to perform a hydrolysis reaction. After a few minutes, the resulting transparent solution was transferred to a sealed container and kept in a constant temperature bath at 60°C. It solidified within about 1 hour.The solidified sample was further aged for several hours, washed several times with distilled water and ethanol, and then dried at 60°C.The dried sample had uniform pores of about 0.54 Lm. existed in an entangled structure. By changing the concentration of polymer in the reaction solution and the reaction temperature, porous bodies with different pore diameters were obtained. These dried samples were subjected to a prescribed heat treatment. Porous silica glass with a structure similar to that of Habo was obtained.

Example 6: When using polyethyleneimine as an organic polymer Example 6-1 First, 50% of polyethyleneimine having a nitrogen primitive in the main chain
Weight% aqueous solution (Aldrich product number 18197-8
) was diluted to 20% by weight, and 2.54g of 62% by weight concentrated nitric acid and 1 mQ of water were added to 6.25g of this solution to make a homogeneous solution. Add 5m+ of tetramethoxysilane to this solution while stirring.
Q was added to carry out a hydrolysis reaction. After several minutes, the resulting transparent solution was transferred to a sealed container and kept in a high temperature bath at 60°C, whereupon it solidified within about 2 hours. After the solidified sample was further aged for several hours and washed several times with distilled water and ethanol,
It was dried at 60°C. In the dried sample, pores of about 0.1 μm were present in an entangled structure. By changing the concentration of polymer in the reaction solution and the reaction temperature,
Porous bodies with different pore sizes were obtained. By subjecting these dried samples to a predetermined heat treatment, porous silica glass having a structure similar to that of Habo was obtained.

In the above example, porous silica glass was obtained because the raw material was tetraalkoxysilane, but if a raw material made by adding a small amount of other metal alkoxide to tetraalkoxysilane was used, various SiO□-based porous glass could be obtained in the same way. High quality ceramics can be obtained. In addition, similar porous ceramics can be obtained even if the heating rate and the maximum heating temperature are slightly changed.

[Comparative Example] 0.00 mQ of tetraethoxysilane. 200 n+Q of O1 normal hydrochloric acid was added and stirred. Then add 10 to 50
% by weight of polyvinyl acetate emulsion was added and dispersed. Ammonia is then added to this to bring the pH value to ~3.
After adjusting the temperature to 5 to 6.6, put it in an airtight container and heat it to 20 to 30.
The mixture was allowed to stand at ℃ to form a gel. Next, this was fired to produce porous glass. The results of measuring the pore diameter of this porous glass are plotted in FIG. 1 with marks. As is clear from the figure, the pore diameters are distributed over a wide range.

[Effects of the Invention] According to the present invention, porous ceramics having uniform pore diameters ranging from submicrons to several tens of microns can be easily provided.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are diagrams showing pore size distribution maps. Special feature: “Questioner” Hiroshi Daimon

Claims (2)

[Claims] (1) Prepare a reaction solution containing a metal alkoxide or its oligomer and an organic polymer, hydrolyze and polymerize the metal alkoxide or its oligomer in the solution to create a gel, and bake the gel to form a porous A method for producing quality glass, wherein the organic polymer is compatible with a solution of the metal alkoxide or its oligomer, and in the hydrolysis/polymerization step, phase separation occurs and substantially no precipitation occurs. A method for producing porous glass that does not produce (2) The method for producing porous glass according to claim (1), wherein the organic polymer is sodium polystyrene sulfonate, polyacrylic acid, polyallylamine, polyethyleneimine, polyethylene oxide, or polyvinylpyrrolidone.