JPH0565449B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for producing a glass body by heating and sintering a porous gel obtained by a hydrolysis reaction of a metal alkoxide. It relates to a method of imparting some kind of function to a glass body.

(Prior art and its problems) Metal alkoxides (e.g. ethyl silicate: Si
(OC ₂ H ₅ ) ₄ etc.) before or during the process of hydrolyzing, adding an aqueous solution containing salts (metal ions) that color the glass, drying and firing to obtain colored glass, for example, Unexamined Japanese Patent Publication 1987-
It is known from publications such as No. 11845 and Japanese Patent Application Laid-open No. 185441/1983. These methods are interesting as a means of developing a glass manufacturing method called the sol-gel method, and are characterized by the ability to easily obtain colored quartz glass, which is difficult to obtain using normal melting methods. It has the advantage of not requiring much high-temperature firing in the manufacturing process.

However, the conventional sol-gel method is not without drawbacks. For one thing, conventional methods are not without drawbacks. One is that conventional methods have only proposed so-called colored glasses, in which metal ions with a coloring function are contained in the glass.Second, there are circumstances that cannot be avoided from the sol-gel method. Moisture remains in the glass, and this moisture acts as a harmful substance when the glass performs various functions.Furthermore, when it dries after hydrolysis, it tends to crack or distort, and the thickness (to a certain extent) For example, it is difficult to obtain a glass body with a thickness of 5 mm or more), which poses a serious obstacle to creating functional glass that requires a certain degree of thickness.

(Problems to be Solved by the Invention) In view of the above-mentioned drawbacks of the sol-gel method, the present invention aims to reduce the amount of water remaining in the glass as much as possible, and to create a glass body with considerable thickness. The purpose of this paper is to propose a method for producing glass that fully demonstrates its performance.

(Specific Means for Solving the Problems) That is, the present invention involves stirring a mixed solution containing at least a metal alkoxide serving as a glass matrix and an aqueous solution dissolving ions that give functions to the glass, This method of manufacturing functional glass is characterized by spreading a sol solution into a thin film, drying it, then laminating a plurality of glass materials made into thin films and firing them into one piece.

To explain in more detail below, the functional glass referred to here means not only colored glass and spectral filter glass, but also light emitting glass, laser oscillation glass, electrically conductive glass, photosensitive glass, etc. It can be created by mixing active metal ions that give glass functionality. The following are examples of ion species that should be mixed in various functional glasses: (1) Laser oscillation glass Neodymium ion (Nd ³⁺ ) Terbium ion (Tb ³⁺ ) Holmium ion (Ho ³⁺ ) Erbium ion (Er ³⁺ ) Yzterbium ion (Yb ³⁺ ) Europium ion (Eu ³⁺ ) (2) Luminescent glass In addition to the ion species listed in the laser oscillation glass above, transition metal ions such as manganese ion (Mn ²⁺ ) Uranium oxide ion ( (3) Electrically conductive glass ^All luminescent ions that can ^be injected, such as complex ions such as UO ₂ ²⁺ ); ⁽ 3) Electrically ^conductive glass; In addition to hopping conduction type ions, metal particles and carbon particles can be precipitated in glass. (4) Colored glass (spectral filter glass) All heavy metal ions known to color glass (e.g. Cr ^{3 +} (green), Fe ³⁺ (brown), Nd ³⁺
(light purple), Er ³⁺ (pink), etc., and these ionic species often exist as oxides in glass. Of course, the present invention is not limited to the functions or ionic species described above.

The metal alkoxide used as the glass matrix used in the present invention is a metal alkoxide of a metal oxide that can form a network structure on top of the glass structure, and the metal alkoxides that are relatively easily available today include:
Methyl silicate (Si(OCH ₃ ) ₄ ), ethyl silicate (Si
(OC ₂ H ₅ ) ₄ ), propyl silicate (Si(OC ₃ H ₇ ) ₄ ), methyl borate (B(OCH ₃ ) ₃ ), ethyl borate (B
(OC ₂ H ₅ ) ₃ ), methyl phosphate (P(OCH ₃ ) ₅ ), ethyl phosphate (P(OC ₂ H ₅ ) ₅ ), and at least one selected from these metal alkoxides. It is sufficient to use However, in addition to the above-mentioned metal alcoholates, there are examples of metal alkoxides that are used auxiliary. They are, for example, aluminum alkoxides (Al(OR) ₃ :R
is an alkyl group having 1 to 3 carbon atoms), titanium alkoxide (Ti(OR) ₄ :R is an alkyl group having 1 to 3 carbon atoms), and the like.

As mentioned above, there are various types of ions that impart functions to glass, but in the present invention, these active ions are used in the form of an aqueous solution in which they are dissolved. In short, the aqueous solution only needs to have ionic species dissolved in it, but in order to make the ionic material into an aqueous solution, it is of course possible to use a pure aqueous solution, but it is also perfectly acceptable to use an acidic aqueous solution or an alkaline aqueous solution. . In many cases, active ionic materials exist in the form of metals, salts, oxides, and hydroxides, so to dissolve them, in addition to pure water, diluted hydrochloric acid, diluted nitric acid, or diluted sulfuric acid are required. , acetic acid aqueous solution, or ammonium hydroxide aqueous solution is quick and practical as a means of obtaining an aqueous solution. In addition, it is recommended to add an acidic or alkaline aqueous solution because it has a catalytic effect to promote the hydrolysis reaction of the metal alkoxide by adjusting the solution.

Water is necessary as a solvent because it causes the hydrolysis reaction to occur. However, if the ionic species is added in the form of an aqueous solution, it may not be necessary to add it separately as water. Furthermore, assuming that the liquid mixture is in the form of an extremely thin film, the water is supplied from the air, so it may not even be necessary to add water to the liquid mixture at all. As mentioned above, the addition of an acid or alkaline solution as a solvent promotes the hydrolysis reaction, so it is preferable to add the acid or alkaline solution. Furthermore, as a metal alkoxide, M(OCH ₃ )
When x is used, it is preferable to add methyl alcohol as a component of the solvent, and add ethyl alcohol using M(OC ₂ H ₅ ) x as a component of the solvent because this promotes the hydrolysis reaction. It can be said that this is an embodiment.

Next, the appropriate proportions of each component in the liquid mixture to be hydrolyzed will be described. Assuming that 1 mol of silicon tetraalkoxide (Si(OR) ₄ ) is used, the amount of metal ions as ion species can theoretically range from 1PPb to 1.0 mol. In addition, the amount of water (H ₂ O) added can range from no addition to about 100 moles in practical terms, considering that water is supplied from water vapor in the atmosphere.
If the amount is too small, the hydrolysis reaction will be delayed, and if it is too large, there will be problems in the drying and baking steps, so in practice, about 2 to 20 moles is appropriate. Acids such as hydrochloric acid and nitric acid, or alkaline solutions such as ammonium hydroxide, may be added at all or in appropriate amounts, but the maximum amount is about 10 moles, and adding more than that does not seem to make much sense. The lower alcohol added as a component of the solvent acts as a mediator to improve the compatibility between the metal alkoxide and the aqueous solution containing active ions, and as a result, it is recognized that it has the effect of completing the hydrolysis reaction in a short time. The appropriate amount of such lower alcohols to be added is about 0.2 to 10 moles, but the practice of the present invention will not be hindered even if they are not added at all.

Since the hydrolysis reaction of the liquid mixture mixed at the above ratio will proceed only slowly if it is kept as it is, stirring and heating operations are performed to accelerate the reaction. For stirring, there are methods such as using a stirring device using a magnet as a rotor or applying ultrasonic waves to the mixed liquid. The end point of the reaction can be easily detected by a dramatic change, such as immediately after a sudden exotherm occurs or when the mixture becomes transparent. In this way, a sol solution in which the hydrolysis reaction has been completed is obtained. Interestingly, aqueous solutions containing active ionic species that impart functionality to glass can not only be added before and during hydrolysis, but can also be added additionally after the hydrolysis reaction is complete without any hindrance. be.

The obtained sol solution is spread into a thin film on any container or flat surface, left to dry in the air while keeping humidity changes small until it hardens to the extent that it can be handled with tweezers, etc., and then heated at room temperature to about 100℃. It will take a few days to dry slowly. At this point, a considerable amount of water and other unnecessary components will be removed. The thickness of the developed thin film is several tens of microns, with an upper limit of about 1 mm. In any case, homogeneous drying can be achieved by drying in a thin film state. Subsequently, multiple sheets of the obtained thin film bodies were laminated,
Up to 600℃, the temperature is increased at a rate of 10 to 50℃/h.
From 600°C to 900°C, a foaming phenomenon occurs due to OH groups, so the temperature is raised even more slowly to produce a thick glass body. To prevent foaming caused by OH groups during firing, it is possible to create dense functional glass without bubbles by firing in a halogen gas atmosphere such as chlorine gas, or firing in a vacuum degassing atmosphere. That's what you get.

(Function) The method for producing glass by the sol-gel method of the present invention is as follows:
Since it is possible to obtain a functional glass and also to obtain a glass with a desired thickness and a low water content, the glass body can easily perform its functions.

(Example 1) 100ml containing 20ml of ethyl silicate (Si(OC ₂ H ₅ ) ₄ )
For a ml beaker, 12N hydrochloric acid/water = 1/
Add ferric chloride (Fecl ₃ ,
An aqueous solution containing 10 g of 6H ₂ O) is prepared, and 4 ml of this aqueous solution is mixed with 20 ml of the above-mentioned ethyl silicate. Additionally, 3 ml of ethyl alcohol and 3 ml of water
The resulting mixed solution was stirred at room temperature using a stirring device using a magnetic rotor. When the mixture was stirred for about 5 minutes, the mixture generated heat and subsequently became transparent, so stirring was stopped after a while to obtain a yellow sol in which the hydrolysis reaction had proceeded. Next, this sol body was spread on an acrylic resin plate to a thickness of approximately
Roll it out thinly to 0.5mm, dry and harden it at room temperature for a few days while keeping humidity changes small, heat dry it in a heating oven at 100℃ for 3 days, cut it into an appropriate size, and make 20 sheets. Laminated to a temperature of 1000℃
A fired glass body was obtained by gradually raising the temperature until . The resulting glass body was brown colored quartz glass with a maximum thickness of 7 mm.

(Example 2) 3 g of metal neodymium (Nd) was dissolved in 12N hydrochloric acid/
Aqueous solution obtained by dissolving 1/4 water in 30ml of diluted hydrochloric acid.
When the mixture (light blue) obtained by mixing 2.3 ml with 20 ml of ethyl silicate and adding 3 ml of water and 3 ml of ethyl alcohol was stirred with a magnetic rotor for about 10 minutes, a sudden heat generation occurred. The liquid became transparent and turned a clear purple color. The obtained sol body after the hydrolysis reaction is spread thinly in exactly the same manner as in Example 1, dried, laminated, and fired. However, the inside of the firing furnace was made airtight, and the inside was vacuumed before firing. The maximum temperature for firing is 1050℃. The neodymium-containing quartz glass thus obtained is a light purple transparent glass with no bubbles inside. This glass exhibited a fluorescence spectrum similar to that of similar glasses made using plasma methods.

In addition, an oscillation experiment using xenon (Xe) flash lamp excitation revealed that the device oscillated stably at a repetition rate of 10Hz or more, and had excellent heat load resistance.

(Example 3) 10 ml of an aqueous solution obtained by dissolving 5 g of europium oxide (Eu ₂ O ₃ ) in 20 ml of 10% by weight water-diluted nitric acid was mixed with 20 ml of methyl silicate (Si(OCH ₃ ) ₄ ), and then Add 3 ml of methyl alcohol to the mixture and add approx.
Stir with a magnetic rotor for 15 minutes and then hydrolyze. Spread the resulting transparent sol (light pink) on an acrylic resin plate to a thickness of about 0.4 mm, and dry in air at room temperature to form a gel. After hardening,
When heating drying and lamination firing were performed in the same manner as in Example 1, a pink erbium-containing quartz glass having a thickness of 5 mm was obtained. In order to confirm the luminescent properties of this glass, when we irradiated it with 365 nm ultraviolet light and placed it in a dark place, we observed that it emitted orange visible light.

(Effects) The method for manufacturing functional glass of the present invention is as described above, and unlike the conventional glass manufacturing method using the sol-gel method, when creating thick glass, distortions and cracks occurred. On the other hand, according to the present invention, hardened thin films are laminated and sintered, which is less likely to cause distortion or cracking, and is suitable for use with laser oscillation glass or figurative jewelry, which require a certain thickness as functional glass. It is fully compatible with glass, etc., and if fired under vacuum suction,
It is also possible to prevent air bubbles from remaining inside the glass body. Moreover, since the drying process is performed in a thin film state, unnecessary alcohol and
Water, residual acid components, etc. can be reduced as much as possible with low energy, and the spectral characteristics of glasses whose functions are inhibited by the presence of water in the glass, such as spectral filter glass, light-emitting glass, and laser oscillation glass. This makes it possible to obtain functional glass whose functions such as light emitting properties are not inhibited.

Claims (1)

[Claims] 1. A mixed solution containing at least a metal alkoxide serving as a glass matrix and an aqueous solution containing dissolved ions that impart functionality to the glass is stirred to develop a sol solution after a hydrolysis reaction into a thin film. A method for producing functional glass, which comprises laminating a plurality of thin glass materials after drying and firing them into one piece. 2. The method for producing functional glass according to claim 1, wherein the firing is performed in a vacuum atmosphere.