JP2587876B2 - Method for producing glass from liquid phase - Google Patents

Description

The present invention relates to a method for producing glass from a liquid phase by a sol-gel method, and more particularly to a method for producing glass using a metal alkoxide as a raw material.

(Prior art) As a method for producing high-performance or high-quality glass,
The melting method, the chemical vapor reaction method, the sol-gel method, etc. are known. However, the melting method requires a high temperature of 2200 to 2300 ° C. It has a drawback that it flows out and the conversion efficiency of raw materials into glass is low.

On the other hand, the sol-gel method is a method for producing glass by gelling a solution or sol and heating the gel, and is a method designed to overcome the difficulties of the melting method or the chemical vapor method. Low temperature heating enables the production of glass, and has the advantage that the conversion efficiency of raw materials to glass is close to 100%. However, when the starting solution or starting gel is converted to a dried gel, or when dried, the dried gel is heated. Cracking, crushing, and deformation due to abnormal expansion occur during the conversion to a glass body, which has the disadvantage that it is difficult to obtain a large glass body.

Therefore, as a method of obtaining a large glass body while compensating for these disadvantages, a method using a sol of metal oxide fine particles as a starting material, and a method of adding metal oxide fine particles to a metal alkoxide solution in advance have been proposed. However, in these methods, the dry gel body is converted to a transparent glass body at 1200 ° C.
The above-mentioned heating temperature is required, and the advantage of the sol-gel method described above is impaired.

On the other hand, a method for producing glass using a starting solution containing only a metal alkoxide as a glass source has also been proposed.
In this method, although the sintering temperature when converting the dried gel body into glass is low, cracks are liable to be crushed particularly when the soft gel in which the solution is gelled is changed to the dried gel body by drying.

The cracks and fractures caused by this manufacturing method may be due to the fact that the skeleton of the gel body cannot withstand the compression due to the large surface tension applied when the gel body shrinks due to the evaporation of water in the solution due to the fine pores and the gel. It is believed that this occurs because the difference in drying shrinkage between the portion near the free surface of the body and the portion far from the free surface increases, causing a large stress between the two portions.

Therefore, as a method to prevent cracks and fractures, for example,
Measures such as autoclave drying under supercritical conditions, gently heating drying, adding a large amount of hydrochloric acid, and using formamide or N, N-dimethylformamide as a drying control agent are being taken. . However, it is difficult to obtain a sufficiently large dried gel body by a method of performing autoclave drying or a method of using a large amount of hydrochloric acid, and a method of drying slowly requires a long time for glass production and is not practical. Further, when formamide or N, N-dimethylformamide is used as a drying control agent, there is a drawback that the influence of a base or an acid as a catalyst is large and conditions are difficult to set.

The present invention has been made in view of the above background, and its purpose is to prevent the occurrence of cracks or fractures at the time of conversion to a dry gel, and to avoid raising the temperature of sintering. It is an object of the present invention to provide a method for producing a glass by a sol-gel method that can obtain a transparent and large-sized glass.

[Configuration of the invention]

(Means for Solving the Problems) In the present invention, a solution in which a metal alkoxide is further used, if necessary, in combination with another metal compound is hydrolyzed to form a sol, which is gelled to form a dried gel body, In a method for producing a glass to be sintered, a polyamic acid, an N, N-dimethylacetamide solution of the polyamic acid,
This is a method for producing glass from an N-methylpyrrolidone solution of a polyamic acid and / or a liquid phase containing an organic compound having a maleimide group. Further, other metal compounds include metal acetylacenate, metal carboxylate, metal nitrate, The present invention relates to a method for producing glass from a liquid phase using metal oxyhydrochloride or metal chloride.

That is, in the method for producing glass from the liquid phase, polyamic acid, N, N-dimethylacetamide solution of polyamic acid, N-methylpyrrolidone solution of polyamic acid, and / or an organic compound having a maleimide group are essential components as starting materials. Manufacturing method.

The polyamic acid in the above-mentioned production method is mixed well with a neutral or basic hydrophilic solvent.

In the present invention, the polyamic acid is, in principle, a polymer having an amide group and a carboxyl group in a molecule obtained by reacting a diamine with tetracarboxylic dianhydride, and if necessary, such as aminoacetylene or allylamine. An appropriate amount of diamine anhydride such as monoamine, maleic anhydride, hexahydrophthalic anhydride, Diels-Alder adduct of methylcyclopentadiene and maleic anhydride, and tricarboxylic anhydride such as trimellitic anhydride may be added at the time of resin synthesis.

As the diamine, for example, 4,4'-diaminodiphenyl ether 4,4'-diaminodiphenylmethane, 4,4 '
Aromatic diamines such as diaminodiphenyl sulfone,
Examples thereof include aliphatic diamines such as 1,4-diaminobutane and hexamethylenediamine.

Examples of the tetracarboxylic dianhydride include aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride and benzophenone tetracarboxylic dianhydride.

In the present invention, the organic compound having a maleimide group in the skeleton is not particularly limited, and examples include bismaleimide and polymaleimide.

In the present invention, the alkyl group of the metal alkoxide is not particularly limited. Examples of the metal alkoxide include lithium methoxide, sodium methoxide, copper dimethoxide, calcium dimethoxide, strontium diethoxide, barium diethoxide, zinc diethoxide, and the like. Examples thereof include boron trimethoxide, aluminum triisopropoxide, gallium triethoxide, yttrium tributoxide, tetramethoxysilane, tetraethoxysilane, germanium tetraethoxide, tetrabutoxide lead, and tungsten octaethoxide.

In the present invention, other metal compounds are not particularly limited. Examples of the metal acetylacetonate include zinc acetylacetonate and indium acetylacetonate, and examples of the metal carboxylate include lead acetate. , Yttrium stearate,
Examples of barium oxalate include metal nitrates such as yttrium nitrate and nickel nitrate. Examples of metal oxychlorides include zirconium oxychloride and aluminum oxychloride. Examples include titanium tetrachloride.

There is no particular limitation on the amount of water to be used for the hydrolysis.
It is 5 to 500 parts by weight based on parts by weight. Further, alcohols and basic substances may be added to increase the compatibility of the metal alkoxide, water, polyamic acid or polyamic acid solution.

In the step of forming a dried gel, for example, if this is performed in a glass container, the gel adheres to the glass wall and cracks occur in the dried gel during shrinkage. It is desirable to use a container made of a fluororesin or the like having a heat resistance of about ℃, a container coated with a fluororesin, or a container made of a polymethylpentene resin or the like.

Dry the gel in the above container at a drying temperature of 120
It is desirable to carry out at ~ 150 ° C. When the drying temperature is lower than 120 ° C., for example, when the drying is performed at a low temperature of 100 ° C., cracks are easily generated immediately before the completion of the drying of the gel, and the drying takes a long time.

The dried gel thus obtained is porous having pores on the order of nanometers, and is sintered at a predetermined temperature to be fine and non-porous to obtain glass.

(Examples) The details of the present invention will be described below with reference to examples.

Example 1 0.1% in 3 g (gram) of 5% (weight) N, N-dimethylacetamide solution of polyamic acid synthesized from 4,4'-diaminodiphenyl ether and pyromellitic dianhydride
10 g of ammonia water and 10 g of methanol are added and stirred to form a homogeneous solution. Then, 10 g of tetramethoxysilane is stirred while stirring.
Dropped in minutes. Then, it was placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and kept at 40 ° C. After gelling in this manner, the temperature was raised to 80 ° C for 48 hours, and ten pinholes (about 1 mm in diameter) were opened at 80 ° C to start drying. Thereafter, the temperature was raised to 150 ° C over 96 hours to obtain a brown-colored almost transparent dried gel rod having a diameter of about 17 mm and a length of about 40 mm. The dried gel was sintered in an electric furnace at a rate of 15 ° C./hour up to 1050 ° C. in an atmosphere of air composition. As a result, a transparent silica glass rod having a diameter of about 12 mm and a length of 28 mm was obtained. The density of this glass was 2.2 g / cm ³ , the same density as commercially available quartz glass.

Example 2 10 g of 0.1% ammonia water and 10 g of methanol were added to 3 g of a 5% N-methylpyrrolidone solution of polyamic acid synthesized from 4,4'-diaminodiphenylmethane and benzophenonetetracarboxylic dianhydride, and the mixture was stirred. After that, 10 g of tetramethoxysilane was added dropwise over 10 minutes while stirring. Then, it was placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and kept at 40 ° C. After gelling in this manner, the temperature was raised to 80 ° C for 48 hours, and ten pinholes (about 1 mm in diameter) were opened at 80 ° C to start drying.
Thereafter, the temperature was raised to 150 ° C over 96 hours to obtain a brown-colored almost transparent dried gel rod having a diameter of about 17 mm and a length of about 40 mm. The dried gel was sintered in an electric furnace at a rate of 15 ° C./hour up to 1050 ° C. in an atmosphere of air composition. As a result, a transparent silica glass rod having a diameter of about 12 mm and a length of 28 mm was obtained. The density of this glass is 2.2g / c
m ³ and the same density as commercial quartz glass.

Example 3 0.1% in 3 g of polyamic acid having double bonds at both ends synthesized from 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and tetrahydrophthalic anhydride
10 g of ammonia water and 10 g of methanol are added and stirred to form a homogeneous solution. Then, 10 g of tetramethoxysilane is stirred while stirring.
Dropped in minutes. Then, it was placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and kept at 40 ° C. After gelling in this manner, the temperature was raised to 80 ° C for 48 hours, and ten pinholes (about 1 mm in diameter) were opened at 80 ° C to start drying. Thereafter, the temperature was raised to 150 ° C over 96 hours to obtain a brown-colored almost transparent dried gel rod having a diameter of about 17 mm and a length of about 40 mm. The dried gel was sintered in an electric furnace at a rate of 15 ° C./hour up to 1050 ° C. in an atmosphere of air composition. As a result, a transparent silica glass rod having a diameter of about 12 mm and a length of 28 mm was obtained. The density of this glass was 2.2 g / cm ³ , the same density as commercially available quartz glass.

Example 4 5% N, N of polyamic acid synthesized from 4,4'-diaminodiphenyl ether and pyromellitic dianhydride
-10 g of 0.1% ammonia water in 3 g of dimethylacetamide solution,
After adding 10 g of methanol and stirring to make a homogeneous solution, 8 g of tetramethoxysilane and 2 g of tetraisopropoxyzirconium
g of the mixture was added dropwise over 10 minutes with stirring. Then, it was placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and kept at 40 ° C. After gelling in this manner, the temperature was raised to 80 ° C for 48 hours, and a pinhole (about 1 mm in diameter) was obtained at 80 ° C.
mm) and drying was started. Thereafter, the temperature was raised to 150 ° C over 96 hours to obtain a brown-colored almost transparent dried gel rod having a diameter of about 17 mm and a length of about 40 mm. The dried gel was sintered in an electric furnace at a rate of 15 ° C./hour up to 1050 ° C. in an atmosphere of air composition. As a result, a transparent glass rod having a diameter of about 12 mm and a length of 28 mm was obtained.

Example 5 5% N, N of polyamic acid synthesized from 4,4'-diaminodiphenyl ether and pyromellitic dianhydride
-10 g of 0.1% ammonia water in 3 g of dimethylacetamide solution,
After adding 10 g of methanol and stirring to make a homogeneous solution, 9 g of tetramethoxysilane and 1 g of tetraisopropoxyzirconium
g of the mixture was added dropwise over 10 minutes with stirring. Then, it was placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and kept at 40 ° C. After gelling in this manner, the temperature was raised to 80 ° C for 48 hours, and a pinhole (about 1 mm in diameter) was obtained at 80 ° C.
mm) and drying was started. Thereafter, the temperature was raised to 150 ° C over 96 hours to obtain a brown-colored almost transparent dried gel rod having a diameter of about 17 mm and a length of about 40 mm. The dried gel was sintered in an electric furnace at a rate of 15 ° C./hour up to 1050 ° C. in an atmosphere of air composition. As a result, a transparent glass rod having a diameter of about 12 mm and a length of 28 mm was obtained.

Example 6 5% N, N of polyamic acid synthesized from 4,4'-diaminodiphenyl ether and pyromellitic dianhydride
-10 g of 0.1% ammonia water in 3 g of dimethylacetamide solution,
After adding 10 g of methanol and stirring to form a homogeneous solution, a mixture of 9 g of tetramethoxysilane and 1 g of zinc acetylacetonate was added dropwise with stirring for 10 minutes. Then, it was placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and kept at 40 ° C. After gelling in this manner, the temperature was raised to 80 ° C for 48 hours, and a pinhole (about 1 mm in diameter) was formed at 80 ° C for 10 hours.
Opening and drying were started. Thereafter, the temperature was raised to 150 ° C over 96 hours to obtain a brown-colored almost transparent dried gel rod having a diameter of about 17 mm and a length of about 40 mm. The dried gel is heated at a rate of 15 ° C / hour in an atmosphere of air composition in an electric furnace.
The temperature was raised to 1050 ° C. for sintering. By this, about 12m in diameter
A transparent glass rod with a length of 28 mm and a length of 28 mm was obtained.

Example 7 3 g of a 5% N, N-dimethylacetamide solution of bismaleimide synthesized from 4,4'-diaminodiphenylmethane and maleic anhydride was added to 10 g of 0.1% aqueous ammonia and 10 g of methanol.
After adding 0 g and stirring to form a homogeneous solution, 10 g of tetramethoxysilane was added dropwise with stirring for 10 minutes. Then, it was placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and kept at 40 ° C. After gelling in this way 80
Temperature rise to ℃ in 48 hours, pinhole at 80 ° C (diameter about 1mm)
, And drying was started. Thereafter, the temperature was raised to 150 ° C over 96 hours to obtain a brown-colored almost transparent dried gel rod having a diameter of about 17 mm and a length of about 40 mm. The dried gel was sintered in an electric furnace at a rate of 15 ° C./hour up to 1050 ° C. in an atmosphere of air composition. As a result, the diameter
A transparent silica glass rod of 12 mm and length of 28 mm was obtained. The density of this glass was 2.2 g / cm ³ , the same density as commercially available quartz glass.

Comparative Example 1 To a mixed solution of 10 g of water and 5.5 g of methanol was added 10 g of tetramethoxysilane at a time, and the mixture was stirred at room temperature for 10 minutes, then placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and closed. It was kept at ° C. After gelation in this way
The temperature is raised to 80 ° C in 48 hours, and a pinhole (approx.
m) were opened and drying was started. Thereafter, the temperature was raised to 150 ° C over 96 hours to obtain a dried gel, which had been pulverized into countless small pieces.

Comparative Example 2 Water 10 g, methanol 5.5 g, N, N-dimethylformamide 3 g
10g of tetramethoxysilane at a time to the mixed solution of
After stirring at room temperature for 10 minutes, the mixture was placed in a polymethylpentene resin cylinder, covered with aluminum foil, sealed and kept at 40 ° C. After gelling in this manner, the temperature was raised to 80 ° C for 48 hours, and ten pinholes (about 1 mm in diameter) were opened at 80 ° C to start drying. Thereafter, the temperature was raised to 150 ° C over 96 hours, but the dried gel was broken into countless small pieces.

〔The invention's effect〕

According to the present invention, large-sized glass free from cracks and cracks can be easily obtained by the sol-gel method. The dried gel body, which is a precursor of glass obtained by the present invention, is a composite in which porous glass and polyimide are composited in a nano size, and can be used as a lightweight structural material having excellent heat resistance and thermal shock resistance.

Claims (2)

(57) [Claims] 1. A method for producing a glass in which a solution of a metal alkoxide, which is further used in combination with another metal compound as required, is hydrolyzed into a sol, which is gelled, dried, and then sintered. , A polyamic acid, an N, N-dimethylacetamide solution of the polyamic acid,
A method for producing glass from a liquid phase, comprising an N-methylpyrrolidone solution of a polyamic acid and / or an organic compound having a maleimide group. 2. The method for producing glass from a liquid phase according to claim 1, wherein metal acetylacetonate, metal carboxylate, metal nitrate, metal oxyhydrochloride or metal chloride is used as the other metal compound.