JP3959660B2 - Method for producing SnO-containing glass powder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing SnO-containing glass powder .
[0002]
[Prior art]
SnO—P ₂ O ₅ glass containing a large amount of SnO has been proposed in JP-A-7-69672 and JP-A-9-175833. These glasses can have the same low melting point as PbO-containing glasses, and are being investigated as alternative materials such as CRT frits containing PbO that are currently widely used.
[0003]
The problem with glasses containing SnO is that the oxidation state of Sn is likely to change during the melting process, and the properties of the glass change depending on the melting conditions, and when the oxidation proceeds to the SnO ₂ (tetravalent) state, undissolved matter As a result, high quality glass cannot be obtained. For this reason, in order to obtain a stable low melting point glass, it is important that Sn is present in the form of SnO (divalent).
[0004]
Although oxidation of SnO to SnO ₂ is more likely to occur at higher temperatures, it also easily occurs at the melting temperature for obtaining a SnO-containing low-melting glass. For this reason, in the aforementioned patent, the crucible is covered and melted, or a reducing agent is added in the batch to prevent oxidation to SnO ₂ .
[0005]
[Problems to be solved by the invention]
However, when a small amount of glass is melted in a short time on a laboratory scale, the above method can be used. However, when a large amount of glass is melted on an industrial scale for a long time, the oxidation of Sn should be sufficiently prevented. It becomes difficult to form a layer of undissolved material on the glass melt. In particular, in a glass with a high SnO content or a glass with a high melting temperature, the entire upper part of the melt is covered with a thick undissolved material layer. It is difficult to obtain.
[0006]
The objective of this invention is providing the manufacturing method of SnO containing glass powder which can obtain glass with sufficient quality even if it manufactures glass on an industrial scale.
[0007]
[Means for Solving the Problems]
The production method of the SnO-containing glass powder of the present invention is characterized by melting in a nitrogen gas atmosphere when producing a SnO-containing glass powder containing 30 to 80% SnO in terms of mol% .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the method of the present invention will be described in detail.
[0009]
First, a glass raw material is prepared so as to have a desired composition. Here, it is desirable to use a divalent raw material (for example, tin monoxide) as the Sn raw material. If necessary, a reducing agent may be added to the batch.
[0010]
The batch is then melted in a nitrogen gas atmosphere and vitrified. When the batch is melted in a nitrogen gas atmosphere, the oxidation of Sn is prevented and the generation of undissolved substances can be suppressed.
[0011]
Then, molten glass is shape | molded and SnO containing glass is obtained.
[0012]
Examples of the SnO-containing glass that can be suitably produced by this method include glasses containing SnO as a main component, such as SnO—P ₂ O ₅ glass and SnO—B ₂ O ₃ —P ₂ O ₅ glass. As the SnO—P ₂ O ₅ glass, for example, a glass having a composition of 30 to 80% SnO, 20 to 50% P ₂ O ₅ and 0.1 to 20% ZnO in terms of mol% can be used. _{As the 2} O ₃ -P ₂ O ₅ glass, for example, a composition of SnO 30 to 80%, B ₂ O ₃ 2 to 50%, P ₂ O ₅ 2 to 50%, ZnO 0 to 20% in terms of mol% is used. The glass which has can be used.
[0013]
Incidentally or SnO-P ₂ O ₅ based glass obtained by the method of the present _{invention, SnO-B 2 O 3 -P} 2 O 5 -based glass has a glass transition temperature of two hundred and eighty to three hundred eighty ° C., 500 ° C. below the temperature Shows good fluidity. However, the coefficient of thermal expansion is as large as about 100 to 150 × 10 ⁻⁷ / ° C. at 30 to 250 ° C., and the mechanical strength is not as large as that of general glass. Therefore, when used as a sealing material, a refractory filler powder can be added and combined to adjust the thermal expansion coefficient and improve the mechanical strength.
[0014]
【Example】
Hereinafter, the present invention will be described based on examples.
[0015]
Example 1
First, a glass having a composition of ₅ % by mole of SnO, 3.0% of B ₂ O ₃ , 32.0% of P ₂ O ₅ , and 5.9% of ZnO is melted in air. The difference when melted in nitrogen gas will be described.
[0016]
First, orthophosphoric acid (liquid) was put into a quartz glass crucible, tin monoxide, boric anhydride and zinc white were added and mixed, and then dried at 120 ° C. Next, this mixture was slowly heated to 600 ° C. in air, and when it became a viscous liquid, it was stirred well to obtain a pre-melt.
[0017]
Melting in air was carried out by covering the crucible containing the pre-melt and raising the temperature to 950 ° C. in a normal electric furnace and holding at this temperature for 1 hour.
[0018]
Melting in nitrogen gas was carried out by transferring the crucible containing the pre-melt to an electric furnace capable of adjusting the atmosphere, raising the temperature to 950 ° C. while supplying nitrogen gas, and holding at this temperature for 1 hour.
[0019]
As a result, when melted in air, an undissolved material layer was formed on the upper part of the melt, resulting in a glass containing a large amount of undissolved material. On the other hand, when melted in nitrogen gas, a glass containing almost no undissolved material was obtained.
[0020]
Next, powder samples made of these glasses were used, and the fluidity during heating was compared by the flow button method.
[0021]
First, glass melted in air and in a nitrogen gas atmosphere was pulverized and passed through a sieve having an opening of 65 μm to obtain glass powder. Next, 3.70 g of this glass powder was pressed on a button having a diameter of 20 mm by a mold, placed on a window glass, subsequently heated to a temperature of 450 ° C. at a rate of 10 ° C./min, and held at this temperature for 10 minutes. . As a result of measuring the spread of the flowed button, the sample made of glass melted in air only flowed 22 mm, whereas the flow diameter of the sample made of glass melted in nitrogen gas was 27 mm.
[0022]
(Example 2)
Cordierite powder was added to the glass powder produced in Example 1 as a refractory filler powder to produce a composite sealing material. The mixing ratio was 75% glass powder and 25% cordierite powder by volume.
[0023]
Next, 3.43 g of the obtained material was pressed on a button having a diameter of 20 mm, and the fluidity was evaluated in the same manner as in Example 1. As a result, a sample using glass powder melted in the air only flowed 18 mm. On the other hand, the flow diameter of the sample using glass powder melted in nitrogen gas was 22 mm.
[0024]
The cordierite powder used was prepared as follows. First, glass having a stoichiometric composition (2MgO · 2Al ₂ O ₃ · 5SiO ₂ ) was pulverized and passed through a sieve having an opening of 100 μm. Next, this glass powder was heated at 1300 ° C. for 10 hours to precipitate cordierite crystals. Thereafter, the crystallized product was pulverized and passed through a sieve having an opening of 45 μm to obtain cordierite powder.
[0025]
(Example 3)
When a glass having a composition of 62.8% SnO, 36.2% P ₂ O ₅ and 1.0% ZnO was melted in air and nitrogen gas in the same manner as in Example 1, In the glass melted in (1), a thick undissolved layer was formed on the upper part of the melt, whereas in the glass melted in nitrogen gas, an undissolved material was slightly formed, but almost good glass was obtained.
[0026]
Next, 3.60 g of a powder sample made of this glass was pressed onto a button with a diameter of 20 mm, and the fluidity during heating was compared in the same manner as in Example 1. As a result, the sample made of glass melted in air was only 18 mm. While it did not flow, the flow diameter of the sample made of glass melted in nitrogen gas was 22 mm.
[0027]
These facts show that the glass obtained by the method of the present invention has good flowability because it does not contain undissolved substances.
[0028]
【The invention's effect】
As described above, according to the production method of the present invention, high-quality SnO-containing glass can be produced in large quantities on an industrial scale. Therefore, the SnO-containing glass powder can be supplied stably.

Claims (2)

A method for producing a SnO-containing glass powder , characterized by melting in a nitrogen gas atmosphere when producing a SnO-containing glass powder containing 30 to 80% SnO in terms of mol% . SnO 30-80% in mol% display, B ₂ O _Three   2-50%, P ₂ O _Five   It consists of a composition of 2-50% and ZnO 0-20%, The manufacturing method of the SnO containing glass powder of Claim 1 characterized by the above-mentioned.