JPH07291657A - Amorphous frit - Google Patents

Abstract

PURPOSE:To provide a frit capable of sealing a panel and a funnel of a color CRT valve at a low temperature in a short time. CONSTITUTION:This amorphous frit is composed of 60 to 95vol.% powdery glass having a composition satisfying 65 to 80wt.% PbO, 5.5 to 8wt.% B2O3, 3 to 9 wt.% Zn0, 7 to 22wt.% Bi2O3, ZnO+Bi2O3 >=16, 0.2 to 1wt.% SiO2, 0.3 to 2wt.% Fe2O3 and 1.5 to 4.5wt.% CS2 and 40 to 5vol.% refractory filter powder and has a thermal expansion coefficient within a range of 80 to 95X10<-7> deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous frit, and more particularly to an amorphous frit used for sealing a panel and a funnel of a color CRT valve.

[0002]

Conventionally, the seal of the panel and a funnel of a color CRT _{bulb, PbO-B 2 O 3 -ZnO} -S
A crystalline frit composed of a glass powder of io ₂ -BaO system and a refractory filler powder such as zircon is used.
Baking is performed at 0 to 460 ° C. for 30 to 60 minutes.

The crystalline frit used here is excellent in heat resistance, and the valve is 350 to 400 in a later exhaust process.
The feature is that the panel and the funnel do not move even if reheated to ℃.

[0004]

By the way, in recent years, exhaust technology has advanced, and it becomes possible to perform exhaust by heating at a low temperature, and heat resistance against frit has become less demanding than before. Instead, from the viewpoint of energy cost reduction and productivity improvement, it has become important to seal at a lower temperature and in a shorter time.
However, the conventional crystalline frit needs to be fired at a high temperature for a long time as described above in order to obtain desired characteristics, and cannot meet such requirements.

The present invention has been made in view of the above circumstances.
An object of the present invention is to provide a frit capable of sealing a panel and a funnel of a color CRT valve at low temperature in a short time.

[0006]

The present inventors Means for Solving the Problems] Where various _{experiments, PbO-B 2 O 3 -ZnO} -SiO 2
Found that the object can be achieved by using a non-crystalline glass -Fe ₂ O ₃ -Cs ₂ O system, and proposes as a present invention.

That is, the non-crystalline frit of the present invention contains PbO 65 to 80%, B ₂ O ₃ 5.5 to 8%, and Z by weight percentage.
_{nO3~9%, Bi 2 O 3 7~22} %, ZnO + Bi 2
O ₃ ≧ 16, SiO ₂ 0.2 to 1%, Fe ₂ O ₃ 0.3
To 2%, and having a composition of Cs ₂ O1.5~4.5%.

The non-crystalline frit of the present invention has a weight percentage of PbO 65 to 80%, B ₂ O ₃ 5.5 to 8% and Z.
_{nO3~9%, Bi 2 O 3 7~22} %, ZnO + Bi 2
O ₃ ≧ 16, SiO ₂ 0.2 to 1%, Fe ₂ O ₃ 0.3
Glass powder having a composition of ˜2% and Cs ₂ O 1.5-4.5% 60-95% by volume, and refractory filler powder 40-
It is characterized by comprising 5% by volume.

[0009]

The non-crystalline frit of the present invention has high stability of glass, is hard to devitrify, and has good fluidity.
Further, since it contains a specific amount of Cs ₂ O, it has a low glass transition point and softening point. Therefore, it is possible to seal at low temperature and in a short time.

The reason why the glass composition is limited to the above range in the present invention will be described below.

The PbO content is 65 to 80%, preferably 67 to 78%. When PbO is more than 80%, devitrification occurs in the glass, which is not preferable, and when it is less than 65%, the firing temperature becomes too high.

The content of B ₂ O ₃ is 5.5 to 8%, preferably 6 to 7.5%. If the content of B ₂ O ₃ is more than 8%, the chemical durability is lowered, which is not preferable for practical use, and devitrification is likely to occur. On the other hand, if it is less than 5.5%, the meltability of the glass decreases and the fluidity deteriorates.

The content of ZnO is 3 to 9%, preferably 3
~ 8%. If ZnO deviates from this range, devitrification tends to occur.

Bi ₂ O ₃ is a component which improves the fluidity of glass, and its content is 7 to 22%, preferably 8 to.
20%. When Bi ₂ O ₃ is more than 22%, devitrification is exhibited, and when it is less than 7%, the above effect is lost.

It is necessary that the total amount of ZnO and Bi ₂ O ₃ is 16% or less, and if it exceeds this amount, it becomes difficult to stabilize the glass.

SiO ₂ is an effective component for stabilizing the glass, and its content is 0.2 to 1%, preferably 0.3 to 1.
0.8%. If the content of SiO ₂ is more than 1%, the glass transition point and the softening point will be high, and the firing temperature will be too high. Further, if it is less than 0.2%, it becomes difficult to obtain the above effects.

Fe ₂ O ₃ is an effective component for stabilizing glass, and its content is 0.3 to 2%, preferably 0.8.
~ 1.5%. If the content of Fe ₂ O ₃ is more than 2%, the glass transition point and the softening point become too high, and if it is less than 0.3%, it becomes difficult to obtain the above effects.

As described above, SiO ₂ and Fe ₂ O ₃ are essential components for stabilizing the glass in this composition system, and the total amount thereof is particularly in the range of 1.0 to 2.5%. It is preferable. The reason is that if the total amount of these components is too small, the glass becomes unstable, and if it is too large, the firing temperature becomes high.

Cs ₂ O is a component that lowers the melting point of glass, and its content is 1.5 to 4.5%, preferably 1.
5 to 4%. When Cs ₂ O is more than 4.5%, devitrification is exhibited, and when it is less than 1.5%, sealing at low temperature becomes difficult.

The frit having the above composition has a glass transition point of about 270 to 285 ° C. and a softening point of 340 to 350.
It has a good fluidity because it is at about ℃ and is non-crystalline. Therefore, the firing can be performed at a low temperature of about 390 to 410 ° C. and in a short time of about 5 to 15 minutes.
However, the coefficient of thermal expansion may not match depending on the material to be sealed. Further, the frit may flow too much to obtain a good seal shape, or the mechanical strength may be insufficient. In such cases, refractory filler powder can be added to improve these properties.

In the present invention, when the refractory filler powder is used, the proportion thereof is 60 to 95% by volume of glass powder,
40-5% by volume of refractory filler powder, especially glass powder 6
5 to 83% by volume, refractory filler powder 35 to 17% by volume
Is desirable. The reason for limiting the ratio of the glass powder and the refractory filler powder in this way is as follows.
If the glass powder content is less than 60% by volume, that is, if the refractory filler powder content is more than 40% by volume, the flowability of the frit is reduced and a good seal shape cannot be obtained, or a dense fired product is difficult to obtain. On the other hand, if the glass powder content is more than 95% by volume, that is, if the refractory filler powder content is less than 5% by volume, it becomes difficult to obtain the above effect. Various types of refractory filler powder can be used, and for example, zircon, tin oxide, zinc silicate, lead titanate, alumina, etc. can be used alone or in combination.

The amorphous frit of the present invention was colored C
When used for sealing an RT valve panel and a funnel, it is desirable to add a refractory filler powder and adjust the thermal expansion coefficient at 30 to 250 ° C. to be 80 to 95 × 10 ⁻⁷ / ° C. That is, in the present invention, when the coefficient of thermal expansion of the frit is within this range, the color CRT is
This is because a moderate amount of strain (tension of about 450 to 1000 psi) is generated in the valve and a high seal strength can be obtained, and if it deviates from this range, abnormal strain occurs and the frit seal part, the panel, and the funnel part. It is more easily damaged.

[0023]

EXAMPLES The amorphous frit of the present invention will be described below based on examples.

Table 1 shows amorphous frit made of the glass powder of the present invention. Note that Sample F in the table is a reference example, and shows glass used in a conventional crystalline frit.

[0025]

[Table 1]

Each sample was prepared as follows. First, lead oxide, boric acid, zinc oxide, bismuth oxide, silicon dioxide, iron oxide, cesium carbonate and barium carbonate were mixed in the proportions shown in the table, put in a platinum crucible and melted at 800 ° C. for 1 hour to obtain glass. After being solidified, it was cast and formed into a film. Next, this was crushed with a ball mill and then classified through a sieve to obtain a powdery sample having an average particle size of 5 μm.

The glass transition point, softening point, pour point and crystallization peak temperature of the sample thus obtained were determined by a differential thermal analyzer (DTA). The thermal expansion coefficient was measured by a dilatometer after molding the obtained glass cullet into 40 × 4 mmφ.

As is apparent from the table, Samples A to E which are examples of the present invention have a glass transition point of 275 to 284 ° C., a softening point of 339 to 345 ° C. and a pour point of 365 to 377 ° C. The coefficient of thermal expansion at ˜250 ° C. is 129 to 1
It was 42 × 10 ⁻⁷ / ° C. No crystallization peak appeared in any of the samples.

The glass used for the conventional frit has a transition point of 321 ° C., a softening point of 398 ° C., a pour point of 428 ° C., and a coefficient of thermal expansion of 106 × 10 ⁻⁷ / 30 to 250 ° C. It was ℃. A crystallization peak appeared at 520 ° C.

Tables 2 and 3 show examples of the present invention (Sample N) prepared by mixing Samples A to E with refractory filler powder.
o. 1 to 9) are shown. Sample No. 10 and 1
Reference numeral 1 is a reference example, and shows a conventional crystalline frit prepared by mixing the sample F and the refractory filler powder.

[0031]

[Table 2]

[0032]

[Table 3]

Next, the obtained sample was fired at 400 ° C. for 5 minutes to evaluate various characteristics.

As is clear from Tables 2 and 3, the sample No. which is an example of the present invention. 1 to 9 have a flow diameter of 27.5
.About.29.0 mm, the coefficient of thermal expansion at 30 to 250.degree. C. was 84 to 93.times.10.sup.- ⁷ / .degree. C., and the residual strain was 490 to 690 psi (tension). Next, using these samples, a 29-inch color CRT valve was sealed under a firing condition of 400 ° C. for 5 minutes, and the seal shape was evaluated. As a result, the seal thickness was 0.15 to 0.3 mm. Further, the frit appropriately covered the inner and outer surfaces of the valve, and had a good shape without insufficient flow or sagging downward. Further, when the water pressure resistance test of the valves was conducted, all were 6 kg / cm ² or more.

On the other hand, in the reference example, the firing conditions were 440 ° C. and 4
The one set to 0 minutes (Sample No. 10) exhibited the same characteristics as those of the examples of the present invention, but the one baked at 400 ° C. for 5 minutes (Sample No. 11) had a flow diameter of 1
It was 9.2 mm, and the glass did not flow sufficiently. Further, the thermal expansion coefficient is 106 because the amount of precipitated crystals is insufficient.
It was as large as × 10 ^-7 / ° C. Therefore, the residual strain of the panel glass showed an abnormal value of 350 psi (compression). Also, when the frit seal portion was observed, the frit did not sufficiently cover the panel and the funnel, and the seal shape was poor.

The flow diameter is 10 g frit and the diameter is 2
Press into a 0 mm cylindrical shape, place it on a plate glass, and
It shows the diameter after firing at 00 ° C for 5 minutes (440 ° C-40 minutes for sample No. 10). Thermal expansion coefficient is 4
5 minutes at 00 ° C (440 ° C-for sample No. 10)
(40 minutes) The fired frit was molded into 40 × 4 mmφ and measured using a dilatometer. The residual strain was 40 when the same cylindrical sample used for the evaluation of the flow diameter was placed on the panel glass (coefficient of thermal expansion 101 × 10 ⁻⁷ / ° C.).
5 minutes at 0 ° C (440 ° C-4 for sample No. 10)
After baking for 0 minutes, the strain remaining on the panel glass was measured with a polarimeter. In the table, T is tension and C
Indicates compression. For the water pressure resistance test, 400 ° C-5 minutes (for sample No. 10, 4
It is a value obtained by placing a 29-inch color CRT valve sealed under the condition of 40 ° C.-40 minutes) in a water tank and gradually increasing the water pressure outside the valve to measure the pressure at which the valve breaks. If the strength is 3.5 kg / cm ² or more, it is generally considered that there is no practical problem.

Among the refractory filler powders used, 250 mesh pass products were used for tin oxide and zinc silicate, and 350 mesh pass products were used for zircon and lead titanate.

[0038]

As described above, when the amorphous frit of the present invention is used, it is possible to seal the panel and the finennel of the color CRT valve at a lower temperature and in a shorter time as compared with the conventional crystalline frit. It is possible to reduce energy costs and improve productivity.

Claims (3)

[Claims] 1. PbO 65 to 80%, B _{2 by} weight percentage
_{O 3 5.5~8%, ZnO3~9%,} Bi 2 O 3 7~2
2%, ZnO + Bi ₂ O ₃ ≧ 16, SiO ₂ 0.2-1
_{%, Fe 2 O 3 0.3~2%} , Cs 2 O1.5~4.5
A non-crystalline frit characterized by having a composition of%. 2. PbO 65 to 80%, B _{2 by} weight percentage
_{O 3 5.5~8%, ZnO3~9%,} Bi 2 O 3 7~2
2%, ZnO + Bi ₂ O ₃ ≧ 16, SiO ₂ 0.2-1
_{%, Fe 2 O 3 0.3~2%} , Cs 2 O1.5~4.5
% Of the glass powder having a composition of 40% by volume and 40% by volume of the refractory filler powder of 5% by volume. 3. The coefficient of thermal expansion at 30 to 250 ° C. is 8.
The non-crystalline frit according to claim 2, which is in a range of 0 to 95 × 10 ^-7 / ° C.