JPH0248430A - Glass composition for sealing - Google Patents

Abstract

PURPOSE:To obtain glass composition for sealing able to firmly seal panel and funnel of cathode ray tube at low temperature in short time by using inorganic component composed of glass powder having specific composition mixed with low-expanding filler in specific ratio. CONSTITUTION:Said glass composition for sealing is used to seal panel and funnel of cathode ray tube and composed of 70-95wt.% glass powder having the composition described below and 5-30wt.% low-expanding filler. Said glass powder is inherently composed of PbO: 84-87wt.%, B2O3: 11-14wt.%, ZnO: 1-3wt.%, SiO2: 0-5wt.% and Al2O3: 0-5wt.% so as to PbO+B2O3=95-98wt.%. A sealing having excellent strength is performed using said glass composition for sealing at a low temperature below about 420 deg.C for a short time below about 20min. As a low-expanding filler, one having expansion coefficient relatively near the value of glass powder such as alumina, zircon or cordierite is preferable.

Description

[Detailed description of the invention] [Industrial use needle! 1] The present invention relates to a sealing glass composition for sealing panels and channels in cathode ray tubes such as color cathode ray tubes.

[Prior Art] Conventionally, there are glass compositions for sealing cathode ray tube panels and funnels that are sealed by firing at 440 to 450°C for 40 to 60 minutes. There was a need for something that could be sealed in a short time. In response to such a request, Japanese Patent Application Laid-open No. 55-20263 discloses 410-42.
One that can be sealed at a low temperature of 0°C has been proposed. Such a composition contains 77-83% PbO, B, 0% by weight.
．． 7-11%, ZnO7-12%, 5ift 1
3%, R200.01 to 1.5%, and a low expansion filler.

However, even with such a composition, the firing time was still long (not sufficient).

On the other hand, conventionally, in the exhaust process after sealing the panel and the funnel, the sealed body has been reheated to a temperature of 350° C. or higher in order to increase the degree of vacuum inside. In recent years, with the development of vacuum technology, there is no practical problem even if the temperature in the exhaust process is lower than 300°C. The present invention provides a new sealing glass composition that corresponds to the development of vacuum technology, and enables sealing at low temperatures and in a short time.

Note that, as a low melting point composition, one for IC ceramic package seals is well known. This composition contains F in the glass component to lower the melting point, and since this F causes emission slump in cathode ray tubes, these compositions for IC cannot be used in cathode ray tubes.

In addition, fluidity is not a major problem with IC products, but in the case of cathode ray tubes, those with poor fluidity result in a decrease in strength, so products for IC cannot be used as they are.

[Problems to be solved by the invention] The present invention solves the above-mentioned problems that the prior art had, and solves the problems of about 4
The object of the present invention is to provide a glass composition for sealing which can be sealed with excellent strength in a short time of 20 minutes or less at a low temperature of 20° C. or less.

[Means for Solving the Problems] In the present invention, the inorganic component consists of 70 to 95% by weight of glass powder and 5 to 30% by weight of low expansion filler, and the glass powder is essentially PbO 84 to 87% by weight. %B2O$ 11-14% ZnO 1-3% Si0□ 0-5% A1□0.0-5% PbO+B2O, 95-98% Kaunari, sealing glass composition for sealing the panel and funnel of a cathode ray tube It is something that provides something.

The glass powder in the present invention has a glass transition point of 3
The temperature is 20°C or lower, preferably 310°C or lower. When the glass transition point is higher than 320°C, the sealing temperature is 42°C.
If the temperature is below 0°C, fluidity decreases, which is not preferable.

As fillers, all commonly known low expansion fillers can be used, such as quartz glass, β-eucryptite, and lead titanate, but in order to prevent microcracks in glass, alumina, zircon, and cordierite can be used. It is preferable to use a material having an expansion coefficient relatively close to that of glass powder.

The ratio of glass powder to filler is 70 to 95% glass powder and the rest filler in order to reduce fluidity and residual strain in the sealed portion. If the glass powder content is less than 70%, the fluidity will be poor (and the adhesive strength will be reduced, so it is not preferable).
, 95% or more, the residual strain in the bonded portion becomes large, which is not preferable. More preferably the glass powder is 80-9
The range is 0%.

The effects of each component of the glass powder in the present invention are shown below.

PbO acts as a fluxing agent and lowers the glass transition temperature.

If the PbO content exceeds 87% by weight, the glass becomes unstable and the fluidity deteriorates due to crystallization, while if it becomes less than 84%, the glass transition point becomes high and the glass becomes hard and the fluidity deteriorates. Undesirable.

B20. is a component that forms the network of glass and is effective in stabilizing the glass. B20. If it is less than 11%, the glass becomes unstable and fluidity is impaired, and if it is more than 14%, weather resistance deteriorates, so neither is preferable.

SiO□ is the same as B2O3 (it forms a glass network and has the effect of improving weather resistance).

When 5i02 is more than 5%, the glass transition temperature is 320.
It is not preferable because it becomes higher than ℃.

ZnO has the effect of improving the fluidity of glass.
If O is less than 1%, sufficient fluidity cannot be obtained, and if it is more than 3%, the glass becomes unstable and the fluidity becomes worse, so neither is preferable.

A1□0. is effective in stabilizing glass. but,
If it exceeds 5%, the glass becomes unstable, which is not preferable.

If PbO+B2O3 is less than 95%, the glass becomes hard and sufficient fluidity cannot be obtained during sealing, which is undesirable; if it exceeds 98%, the glass becomes unstable and fluidity is hindered by crystallization during sealing. So I don't like it.

[Example] Examples according to the invention are shown below.

The raw materials were mixed to have the glass composition shown in Table 1, and 12
Melt using a platinum crucible in an electric furnace at 00°C. After melting for 1 hour while stirring with a platinum stirrer, the mixture is poured into a tube of a cooled rotating roller to obtain a cullet. The obtained cullet is pulverized in an alumina ball mill 7 to produce a glass powder having an average particle size of about 5 LLm. The glass powder and filler were mixed in the proportions shown in Table 1 using a mixer (2) to prepare a composition according to the present invention. The glass transition point and flow button diameter, which is an indicator of fluidity, are the same (
It is shown in Table 1.

The diameter of the flow button is determined by pressing 10 g of the composition into a cylindrical shape with a diameter of 1/2 inch and placing it on a plate glass.
When fired at 0°C for 10 minutes, the frit spreads on the glass plate, and the diameter at this time was measured.

Table 1 also shows composition No. 7.8°9 as a comparative example. As is clear from Table 1, the composition according to the present invention has a flow button diameter of 2 under the firing conditions of 420°C and 10 min.
The diameter was 6 mm or more, indicating sufficient fluidity for practical use.

The composition according to the invention can be used in the same process as conventional compositions. That is, the composition and vehicle are mixed in an appropriate ratio to form a slurry 2, which is applied to the sealing surface, dried, and fired in a firing furnace. 420 using table INo, 4
20-inch CRT sealed at -10 minutes at °C and No.
1 frit at 420'C for 10 minutes.

The glass powder according to the present invention has a total content of 98% or more of the above components.
-, and the remaining 2% is made up of alkali metal oxides, alkaline earth oxides, and various metal oxides (TLOz, SnO
□, ZrO□, etc.).

The particle size of such glass powder is an average particle size of 4 to 8 LLI.
I+ fillers are preferred, while low expansion fillers having an average particle size of 3 to 6 μm are preferred.

When using the composition according to the present invention, a commonly used vehicle is added to the above-mentioned inorganic components to form a slurry.

The heat resistance strength of the 20-inch cathode ray tube was 50°C or higher, which is much higher than 30°C, which poses a problem in terms of strength, and there was no problem at all. Moreover, it can be completely salvaged in the salvage process by etching with HNO3 solution, and there is no practical problem at all.

[Effect of the invention] As shown in the examples, the present invention
Enables cathode ray tube sealing in a short time of less than 0 minutes,
The obtained valve has no practical problems. Moreover, it can be used in the same work process as conventional ones.

In other words, the firing time is 440 → 420℃ or less and 20℃
The firing time can be reduced by more than half from 40 minutes to less than 20 minutes, which is very economical.

Claims (1)

[Claims] (1) The inorganic component consists of 70 to 95% by weight of glass powder and 5 to 30% by weight of low expansion filler, and the glass powder is essentially 84 to 87% PbO in weight % B_2O_3 11 to 14% ZnO 1 to 3% SiO_20 -5% Al_2O_30-5% PbO+B_2O_395-98% A sealing glass composition for sealing a cathode ray tube panel and funnel.