JPS6035295B2 - Silica glass manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing silica glass.

When manufacturing silica glass using alkoxyl silicon such as Si(CH30)4 as a raw material, conventionally CH30H'
Thus, water containing NH40 was directly added to the diluted Si(CH30)4 solution, solidifying (gelling), and then drying and consolidating to obtain a silica glass body. was. However, in this conventional method, C
Since water containing NH40, which is a reaction catalyst, is directly added to the Sj(CH30)4 solution diluted by H30, if the concentration of N ratio OH in the added water is too high, Sj(
The hydrolysis reaction of CH30)4 is too fast, producing a white precipitate and not solidifying (gelling). On the other hand, if the concentration of N in the added water is too low, the hydrolysis reaction does not proceed and gelation occurs. The drawback was that it was not available.

That is, it is extremely difficult to directly add water containing NH and OH to alkoxyl silicon and hydrolyze it to obtain a uniform gel body, resulting in a drawback that good quality silica glass cannot be obtained. In order to eliminate these drawbacks, the present invention involves adding an appropriate amount of water to alkoxyl silicon as a raw material, mixing it, and then exploding this mixed solution into a gaseous body containing ammonia, which is a reaction catalyst, to solidify (gel)
The purpose is to realize a uniform hydrolysis reaction and provide a method for obtaining a uniform gel body, thereby making it possible to manufacture high-quality silica glass.

FIG. 1 is a diagram showing an embodiment of the present invention, in which 1 is a reaction vessel, 2 is a mixture of alkoxyl silicone, alcohol, and water, 3 is a foaming tube, 4 is piping, 5 is a saturator, and 6 is aqueous ammonia. It is.

In the embodiment shown in FIG. 1, a mixture 2 of alkoxyl silicon, alcohol and water placed in a reaction vessel 1 is mixed with ammonia water containing NH and 0H as reaction accelerators, which is transported from a saturator 5 by Ar gas. After being exposed to the steam for a certain period of time, the foaming tube 3 is taken out and the mixed liquid 2 is solidified. Now, in the above example, mixed liquid 2
As, Si(CH30)4, CH30 day and day 20
When a solution containing 1:2:3 volume ratio was used for 10 days, and a 5% NH solution was used as ammonia water 6 for 40 days, 30 days
A homogeneous gel body was obtained by exposing the mixed solution for 1 minute to a gas containing ammonia which was stirred by Ar gas at 0C/min. On this occasion,
The contact time (exposure time) for gelation depends on the 40-day concentration of NH in the ammonia water, the reaction temperature, and the Si in the mixture.
Depending on the proportion of (CH30)4, NH in ammonia water
The higher the 40-day concentration, the higher the reaction temperature, and the greater the proportion of Si(CH30)4 in the mixture, the shorter the contact time for gelation. In addition, Sj in the mixed liquid
When the ratio of (CH80)4 is below a certain value, no gelation reaction occurs and no gel body is obtained even if the concentration is increased or the reaction temperature is increased.

FIG. 2 is a diagram showing the gelation region of the mixed liquid.

The vertical axis shows the proportion (volume ratio) of Si(CH30)4 and Si(CH30)4, and the axis shows the N concentration (mol %) in the ammonia water with which they are brought into contact. As can be seen from Figure 2, when the Si(CH30)4 ratio in the mixed solution is high, gelation occurs easily even if the N ratio OH concentration in the contact ammonia water is low, but when the mixing ratio of water is increased, gelation occurs. The gel body was not obtained under the condition of the area exceeding the curve shown in FIG. 2. After drying the homogeneous gel body obtained as described above, a high quality transparent silica glass body was obtained by firing at a temperature of 1400 to 1500 oo. In addition, in the present invention, when using a raw material solution in which alkoxyl silicone is mixed with other metal alkyl compounds such as alkoxyl germanium, alkoxyl aluminum, etc. at a certain ratio, the gel can be gelled by the same operation as described above. A doped silica glass body can be obtained by drying and coalescing the gel body. As explained above, according to the method for producing silica glass of the present invention, a homogeneous gel body can be easily obtained using alkoxyl silicon as a raw material, and a high-quality silica glass body can also be obtained from this gel body.

Furthermore, high-quality optical fibers can be obtained using the high-quality silica glass body and doped silica glass body as raw materials.
Moreover, according to the present invention, it is easy to increase the size of the reaction vessel shown in FIG. 1 and manufacture a large amount of silica glass bodies at a time, and the present invention has the advantage of being able to provide inexpensive optical fibers.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a gelation region of a mixed liquid. DESCRIPTION OF SYMBOLS 1... Reaction container, 2... Mixed liquid of alkoxyl silicone, alcohol, and water, 3... Foaming tube, 4...
Piping, 5...Saturation evening, 6...Ammonia water. Figure 1 Figure 2

Claims (1)

[Claims] 1. When producing silica glass using alkoxyl silicon as a raw material, the alkoxyl silicon is mixed with water in advance, and then this mixed solution is exposed to a gas containing ammonia to solidify, and then dried and fired. A method for producing silica glass, the method comprising: obtaining a silica glass body. 2. The method for producing silica glass according to claim 1, wherein the alkoxyl silicon raw material contains another metal alkoxyl compound.