JPH07101740A - Production of porous glass ceramic - Google Patents

Abstract

PURPOSE:To efficiently produce porous glass ceramic contg. a large number of uniformly dispersed pores at a low cost. CONSTITUTION:When a body consisting of at least glass powder and an org. binder is treated, the body to be treated is heated to a temp. at which the glass powder softens and the heated body is further heated to a temp. at which the glass powder is made porous in an oxidizing atmosphere.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a porous glass ceramic which can be used, for example, as an adsorbent, a catalyst carrier, a substrate for electronic parts, a dielectric material for high frequency porcelain capacitors and the like. .

[0002]

2. Description of the Related Art Conventionally, the following methods for producing porous ceramics are known.

First, an organic binder is added to an inorganic powder to thoroughly mix them, and the inorganic powder and the organic binder are uniformly mixed, and then a large number of small organic resin spheres having a particle diameter of about 50 to 60 μm are added and mixed. , Evenly disperse the organic resin spheres.

Next, the mixture in which the organic resin spheres are dispersed is molded into a predetermined shape, and the molded product is heated to 300 to 400 ° C.
Bake at moderate temperature. By this firing, the organic resin spheres in the molded product are burnt out together with the organic binder, and a large number of pores are formed after the organic resin spheres are burnt out.

Next, the molded product having a large number of pores is fired at a temperature of about 1000 to 1300 ° C. By this firing, the inorganic powder is sintered and the molded product becomes a porous ceramic.

[0006]

However, this method is
After mixing the inorganic powder and the organic binder, it is necessary to further add and mix the organic resin spheres, and since the organic resin spheres have a considerably different specific gravity from the inorganic powder, it is difficult to mix them uniformly.
Therefore, there is a problem that it takes time to mix the organic resin balls.

In this method, since the specific gravity of the organic resin spheres is considerably different from that of the inorganic powder, it is very difficult to uniformly disperse the organic resin spheres, and moreover, the organic resin spheres tend to shift over time, Therefore, there is a problem that it is difficult to manufacture a porous ceramic in which pores are uniformly dispersed.

Further, this method has a problem that a large amount of organic resin spheres are required to form pores, so that the manufacturing cost is increased due to the cost of the organic resin spheres.

An object of the present invention is to provide a method for producing a porous glass-ceramic, which can efficiently produce a porous glass-ceramic in which a large number of pores are uniformly dispersed at low cost.

[0010]

A method for producing a porous glass ceramic according to the present invention comprises a step of heating an object to be treated consisting of at least a glass powder and an organic binder to a temperature at which the glass powder softens, and the heating step. And further heating the treated material in an oxidizing atmosphere to a temperature at which the glass powder becomes porous.

Here, the glass powder may be of any type,
It is preferable that the softening temperature is as low as 500 to 800 ° C.
Further, the object to be treated may be formed only by the glass powder and the organic binder, or may contain components other than these. Furthermore, the object to be treated may or may not be molded.

The step of heating the object to be treated to a temperature at which the glass powder softens is a step of decomposing and carbonizing the organic binder contained in the object to be left in the glass powder as carbon, and the residual It can be considered separately as a step of wrapping the carbon thus made in a softened glass.

The heating conditions for decomposing and carbonizing the organic binder contained in the object to be treated and leaving it as carbon in the glass powder are heating temperatures of 250 to 3
The heating time is preferably 50 ° C. and the heating time is 1 to 2 hours.

Further, the steps of decomposing and carbonizing the organic binder contained in the object to be treated and leaving it as carbon in the glass powder and the step of wrapping the remaining carbon in the softened glass are carried out in the atmosphere. However, it is preferably performed in a non-oxidizing atmosphere such as N ₂ or Ar gas or in vacuum.

If the glass is heated to a temperature at which it softens at a heating rate of 300 ° C./hour or more, the step of decomposing the organic binder in the object to be treated and the carbon formed by this decomposition are wrapped in the softened glass. The process can be performed with a single heating.

[0016]

In the invention according to claim 1, when the object to be treated is heated to a temperature at which the glass is softened, the organic binder is decomposed and a part thereof is carbonized, and the carbon formed by the carbonization is softened glass. Wrapped in. When this glass is heated to a higher temperature in an oxidizing atmosphere, the carbon wrapped in the glass burns and gasifies, and this gas causes the glass to foam.

According to the second aspect of the invention, heating until the glass softens is performed in a non-oxidizing atmosphere (N ₂ , A).
r)) or in vacuum, the amount of carbon remaining in the glass powder increases and the amount of carbon wrapped in the glass increases.

Further, in the invention of claim 3, since the temperature rising rate of the heat treatment until the glass is softened is set to be higher than 300 ° C./hour, a large amount of carbon remains in the glass powder and is wrapped in the glass. The amount of carbon increases.

[0019]

【Example】

Example 1 First, 3 parts by weight of an organic binder was added to 50 parts by weight of glass powder, and these were thoroughly mixed by a mulcher. Here, as the glass powder, Na ₂ O · B ₂ O ₃ · SiO _{2 is used.}
-Based borosilicate glass powder (average particle size 0.5 μm) is used, and polyvinyl alcohol (PV
A) was used.

Next, the mixture obtained by the ladle mill is granulated by the granulator, and a predetermined amount of the granulated mixture is put into the mold of the molding machine, and the diameter is 9.95 mm, and the thickness is It was formed into a disk shape having a thickness of 0.50 mm.

Next, the disk-shaped molded product was heated in the atmosphere at 280 to 300 ° C. for 2 hours. The organic binder was decomposed and burned by this heating, and a small amount of carbon component (carbon) remained and disappeared (debinding). When the amount of residual carbon remaining in the molded product was measured, it was 3.0% by weight or less.

Further, this molded product was heated at 800 ° C. for 0.5 hour. By this heating, the glass constituting the molded product is softened, and residual carbon is wrapped in the softened glass.

Next, this molded product was heated to 1000 ° C. to 0.4
When the temperature was raised by heating over time, the carbon encased in the glass was oxidized and turned into CO ₂ gas.
_A large number of bubbles were formed in the object to be processed by the _two gases, and the object became a porous glass ceramic.

When the porosity of this porous glass-ceramic was examined, it was 20-40%. Moreover, when the dispersed state of the pores was examined, it was found to be uniform.

Example 2 280 in an atmosphere of non-oxidizing gas (N ₂ , Ar, etc.)
An experiment was conducted under the same conditions as in Example 1 except that the binder was removed by heating at ˜350 ° C. for 2 hours. In this experiment, the residual carbon remaining in the object to be treated after decarbonization was 5% or less. The porosity of the finally obtained porous glass ceramic was 30 to 40%. Furthermore, when the dispersed state of the pores was examined, it was found to be uniform.

In this experiment, since the object to be treated is heated in a non-oxidizing gas atmosphere, it is considered that the residual carbon is increased and the glass is encased with a large amount of carbon, and the porosity is increased.

Example 3 Example 1 was repeated except that the binder was not removed at a low temperature and the glass constituting the mixture was softened by heating the mixture at a temperature rising rate (> 300 ° C./H) as high as possible. An experiment was conducted under the same conditions as. The porosity of the obtained porous glass-ceramic obtained in this experiment was 10 to 30%. Moreover, when the dispersed state of the pores was examined, it was found to be uniform.

In this experiment, since the rate of raising the temperature of the object to be treated is high, sufficient binder removal is not performed, the amount of residual carbon increases, and a large amount of carbon is included in the glass, resulting in a high porosity. I think that the.

[0029]

According to the invention of claim 1, the glass can be made porous without mixing the organic resin spheres with the object to be treated, so that the organic resin spheres having a specific gravity different from that of the glass powder are used. This eliminates the need for uniform mixing, and therefore the porous glass ceramic can be easily manufactured.

According to the first aspect of the present invention, the carbon wrapped in the glass is burned to be gasified, and the glass is foamed by this gas. Therefore, a large number of pores are dispersed uniformly in the porous glass ceramic. Has the effect that it can be manufactured.

According to the second aspect of the present invention, the amount of carbon remaining in the glass powder increases and the amount of carbon encased in the glass increases, so that a porous glass ceramic having a high porosity can be manufactured. There is an effect that can be.

According to the third aspect of the present invention, since the amount of carbon remaining in the glass powder increases and the amount of carbon encapsulated in the glass increases, it is possible to manufacture a porous glass ceramic having a high porosity. There is an effect that can be.

Front page continued (72) Inventor Riichi Toba 6-16-20 Ueno Taito-ku, Tokyo 6-16-20 Ueno Solar Incorporated (72) Inventor Naoto Narita 6-16-20 Ueno Taito-ku, Tokyo Solar Induction Within the corporation

Claims (3)

[Claims] 1. A step of heating an object to be treated comprising at least glass powder and an organic binder to a temperature at which the glass powder softens, and the heated object to be treated is porous in an oxidizing atmosphere. And a step of further heating to a temperature at which the porous glass-ceramic is produced. 2. The method for producing a porous glass ceramic according to claim 1, wherein the object to be treated is heated in a non-oxidizing atmosphere or in vacuum to a temperature at which the glass powder softens. 3. The method for producing a porous glass ceramic according to claim 1, wherein the object to be treated is heated to a temperature at which the glass powder is softened at a temperature rising rate higher than 300 ° C./hour.