JPH0781975A - Glass material for sealing - Google Patents

Abstract

PURPOSE:To provide the glass material for sealing capable of sealing at a low tamp. at the time of the production of a cathode rays tube by sealing the glass made front panel consisting of the glass having the composition of soda lime silica and a rear plate glass at a peripheral part. CONSTITUTION:The glass material for sealing is obtained by mixing the glass powder having the composition of 77-85wt.% PbO, 8-15wt.% B2O3, 0.1-0.4wt.% SiO2, 2-6wt.% ZnO, 1-8wt.% Al2O3, 0-3wt.% TiO2, 0-1.5wt.% ZrO2, 0-3wt.% TiO2+ZrO2 and 0-2wt.% Sb2O3 and the following crystalline powder so as to obtain the following composition. The composition is 60-92wt.% glass powder, 2-15wt.% zirconia, 0-15wt.% cordierite, 0-25wt.% lead titanate and 0-5wt.% titanium oxide, but when the cordierite and the lead titanate are added, the sum is 4-25wt.%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sealing material having high pressure resistance, excellent water resistance and moisture resistance and used for sealing glass for display using glass of various compositions such as soda lime silica glass. Wearable glass material.

[0002]

2. Description of the Related Art Conventionally, low melting point glass has been used for sealing various display materials such as cathode ray tubes and alumina packages for ICs. Generally, low-melting-point glass has a large expansion coefficient as compared with glass as a material to be sealed, and the expansion coefficient does not match well with the material to be sealed in many cases. For the purpose of solving this problem, we succeeded in reducing the expansion coefficient while maintaining properties such as adhesiveness at low temperatures by mixing low-expansion glass with a low-expansion filler (inorganic crystal filler). ing. For example, U.S. Pat. Nos. 3,250,631 and 3,258,350 and JP-A-49-24208 disclose low melting point glass with β-eucryptite, β-spodumene,
It is disclosed that lead titanate, quartz, zircon and the like are added. In addition, many glass compositions are disclosed which are adapted to various uses by changing the glass composition, the kind and amount of the filler according to the purpose. For example, JP-A-52-56867 proposes a low melting point glass containing cordierite or lead titanate as a filler for hermetic coating and surface stabilization of a semiconductor device. And has good chemical resistance. Japanese Patent Publication No. 54-23928 proposes a material which is suitable for hermetically sealing a semiconductor device by containing lead titanate and zircon in a low-melting glass, and which is particularly resistant to acid during lead wire plating process. ing. JP 61-1 43298 discloses, in JP 56 over 69242 publication, suitable low melting point glass for sealing alumina package for _{IC, PbO-B 2 O 3} -ZnO-SiO 2
_{(-Al 2 O 3 -RO-SnO} 2 over R ₂ 0) obtained by adding a filler of cordierite or the like to the low-melting glass systems have been proposed. Further, Japanese Patent Publication No. Sho 62 over 47,824, by the addition of zircon to a low melting point glass of _{PbO-B 2 O 3 -SiO 2} -Al 2 O 3 system, no darkening even under the application of the DC voltage Glass for sealing display tubes has been proposed.

[0003]

In recent years, a new type of display tube represented by a so-called flat CRT having a small depth has been developed. The glass used for these is glass of soda-lime-silica composition or glass of similar composition, and the expansion coefficient is 80.
Often around 100 × ^10-7 / ℃. Further, when a display tube is manufactured using such glass, the following characteristics are required as a frit for sealing which seals a windshield panel and a glass plate serving as a back plate into a sealed container.

(1) Capable of sealing at 450 ° C. or lower in order to prevent influence on the device inside the container and the glass of the container. (2) Good fluidity and good compatibility with glass and electrode materials.

(3) It is necessary to ensure mechanical durability, and the material strength of the frit and the pressure resistance of the container after sealing are high. (4) It is necessary to ensure chemical durability, and there is no abnormality even when a high voltage is applied under conditions of high temperature and high humidity. (5) The fluidity can be appropriately adjusted according to the application. (6) Coloring can be adjusted. Although some conventional materials generally satisfy the conditions (1) and (2), it is difficult to obtain the ones that simultaneously satisfy the conditions (3) and (4). Regarding (5) and (6), if the frit with good fluidity is used to reduce the fluidity with a small amount of additive and the coloring is reduced, and other properties are less affected, the fluidity can be changed depending on the application. It is convenient that the coloring can be adjusted appropriately, but it has been difficult with the crystal powder that has been conventionally used as a filler. Therefore, the object of the present invention is excellent in water resistance, moisture resistance, high temperature, high humidity, no abnormalities even under conditions of high voltage, and high pressure resistance after sealing, especially glass of soda lime silica composition or it It is an object of the present invention to provide a low-melting-point glass frit, which has a good flowability, matches the glass having a similar expansion coefficient, and can control the flowability and the coloring by adding a small amount of crystal powder.

[0006]

In order to solve the above-mentioned problems, the present invention provides a glass material for sealing which comprises a mixed powder obtained by mixing glass powder with cordierite, lead titanate or zircon crystal powder. The glass powder and the mixed powder had the following composition ratios. Glass powder PbO: 75-85 wt% B ₂ O _3: 8~15 wt% SiO _2: 0.1 to 0.4 wt% ZnO: 2 to 6 wt% Al ₂ O _3: 1~8 wt% TiO ₂ : 0-3 wt% ZrO _2: 0 to 1.5 wt%, however, TiO ₂ + ZrO _2: 0~3 wt% Sb ₂ O _3: 0 to 2 wt% mixed powdered glass powder: 60 to 92 wt% zircon: 2 to 15 wt% Cordierite: 0 to 15 wt% Lead titanate: 0 to 25 wt% Titanium oxide: 0 to 5 wt% However, when cordierite and lead titanate are added, the total of these is 4 -25% by weight.

[0007]

The reason for limiting the composition of the glass for sealing and the reason for limiting the mixing ratio of the glass powder and the crystal powder will be described below.

When the content of SiO ₂ is higher than the upper limit, the fluidity as a frit becomes poor, and at the same time, the pressure resistance of the sealed material is low. If it is less than the lower limit amount, crystallization tends to occur during firing,
Liquidity deteriorates. In addition, water resistance and moisture resistance are also deteriorated. A more preferable composition range is 0.2 to 0.4% by weight.

If Al ₂ O ₃ is higher than the upper limit, the glass tends to devitrify. If the amount is less than the lower limit, crystallization tends to occur during firing, resulting in poor fluidity. In addition, water resistance and moisture resistance are also deteriorated. A more preferable composition range is 1.5 to 6.5% by weight.
Is.

PbO is the most important component for lowering the melting point of glass. If the amount is higher than the upper limit, the glass tends to devitrify, and the water resistance and moisture resistance deteriorate. If the amount is less than the lower limit, sealing at 450 ° C. or less becomes difficult. A more preferable composition range is 78 to 85% by weight.

If B ₂ O ₃ is higher than the upper limit, sealing at 450 ° C. or lower becomes difficult. If the amount is less than the lower limit, the glass tends to devitrify. From the viewpoint of preventing devitrification, it is more preferably 9% by weight or more.

If the content of ZnO is higher than the upper limit, crystallization occurs during frit firing, resulting in poor fluidity. If the amount is less than the lower limit, the water resistance and moisture resistance deteriorate, and the strength also decreases. A more preferable composition is 3.5 to 5% by weight.

TiO ₂ and ZrO ₂ are important components for improving water resistance and moisture resistance. If the amount is higher than the upper limit, the fluidity will be poor and sealing will not be possible at 450 ° C or lower. Ti
Setting the total of O ₂ and ZrO ₂ to 0.1% by weight or more means
It is preferable for increasing water resistance and moisture resistance.

Sb ₂ O ₃ has the effect of weakening the coloring of the sealing glass and improving the pressure resistance of the display tube. Even if the amount is higher than the upper limit, their effects do not change much. Especially S
It is preferable to contain b ₂ O _{3 in an amount} of 0.1% by weight or more in order to weaken the coloring.

Crystal powders, especially cordierite and lead titanate, are necessary for adjusting (decreasing) the expansion coefficient of glass. There are β-eucryptite, β-spodumene, etc. as crystals that have the same function, but since these contain an alkaline component (Li), the volume resistivity becomes small, and by using an electron gun, high voltage can be applied to the glass container. It is not suitable for a cathode ray tube type display tube to which is applied, especially a display tube using glass of soda lime silica composition.

If the amount of cordierite or lead titanate is higher than the upper limit, the expansion coefficient will be too small and the fluidity will be poor. If it is less than the lower limit amount, the expansion coefficient becomes too large. Zircon is a crystalline powder that is important for increasing strength. If it is higher than the upper limit, the fluidity will deteriorate. If it is less than the lower limit amount, the pressure resistance becomes low. A small amount of titanium oxide reduces fluidity and reduces coloring. If the amount is less than the lower limit, it has no effect. To reduce button fluidity by adding titanium oxide, 0.1% by weight or more is preferable, and 0.5% by weight
More preferably, it is 0.8% by weight or more. 5% by weight
If it is contained in a larger amount, the fluidity becomes too low and the hermeticity becomes poor. Further, the expansion coefficient is small, which is not preferable.

[0017]

EXAMPLES The present invention will be described in detail below based on examples. Tables 1 to 4 show the compositions of the sealing glass materials of Examples 1 to 25 of the present invention and the three characteristics of the button flow diameter, the coefficient of thermal expansion and the water resistance.

Raw materials prepared to have the compositions shown in Tables 1 to 4 are put into a platinum crucible and melted at 1000 to 1200 ° C. for 1 to 2 hours. The molten glass is pulverized with water and then pulverized with a ball mill to 100 μm or less. 1 for this powdered glass
A mixed powder (which serves as a filler for inorganic crystals called a filler) pulverized to a size of 00 μm or less is added and homogeneously mixed to obtain the glass material for sealing of the present invention. For sealing various display tubes such as cathode ray tubes, a suitable amount of vehicle (nitrocellulose dissolved in isoamyl acetate solution) is mixed with sealing glass, and a paste is applied to the sealing surface. used.

The characteristics shown in Tables 1 to 4 were evaluated as follows.

[Button flow diameter] Glass powder for sealing 10
g is weighed and press-molded into a cylinder having a diameter of 12.5 mm (pressing pressure of about 100 Kg / cm ² ). This is baked at 450 ° C. for 1 hour on a glass plate having a soda-lime-silica composition (known glass plate manufactured by the float method). Normally, the sample softens and flows, and spreads out in a substantially disc shape. The diameter of this disk is used as the flow diameter and is used as a measure of fluidity. Empirically, if the flow diameter is 25 mm or more, generally good adhesion is possible.

[Thermal expansion coefficient] Measured using a thermal expansion meter,
The average value from 30 ° C. to the glass transition point is shown.

[Water resistance] A glass for sealing is applied to a glass plate having a soda lime silica composition and fired to obtain a water resistance test sample. This is immersed in warm water of 80 ° C. and taken out after 24 hours. The surface of the sample was observed and evaluated for resistance to erosion by hot water.

Some of the items were evaluated as follows. The glass for sealing is applied to a metal plate (which does not substantially elute with hot water at 80 ° C.) in a size of about 50 mm square and fired. This was immersed in warm water of 80 ° C. for 24 hours, the components eluted in the warm water were analyzed, and the amount of elution per unit area was evaluated.

[Pressure Strength] A front glass container and a back plate glass, each of which has a flat display, are sealed with a sealing glass to form a container, and a hydrostatic pressure is applied to the container to perform a pressure resistance test. It was evaluated by

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

In Example 3 and Example 21, a float glass plate having a soda-lime-silica composition was bent to form a flat cathode line having a display portion 11, a side wall portion 12 and a flange portion 13 as shown in FIG. 1 (a). Manufacture front glass 1 for tubes (diagonal length of display is about 36 cm, height of side wall is about 6 cm, glass thickness is 10 mm),
With respect to the back plate 2 (a glass plate having the same composition and a thickness of 10 mm) at the flange portion 13 and the container 3 (the cross section of which is shown in FIG. 1B) sealed with the sealing glass, the compressive strength was measured. went. In the case of using the sealing glass of Example 21, 4.7 Kg / cm ^2, whereas in the sealing glass of Example 3, the pressure resistance strength was improved to 8.0 Kg / cm ² . Further, among the examples, the one to which Sb ₂ O ₃ was added was less colored than the one to which Sb ₂ O ₃ was not added, which was preferable.

Examples 19, 20, 25 and Examples 18, 2
No. 4 is a comparison of the effects of adding titanium oxide powder. As compared with Example 18 in which the titanium oxide powder was not added, in the case where titanium oxide was added, a reduction in button flow diameter was observed. By adding 0.86 to 1.3% by weight, the flow diameter could be reduced by 2 to 3 mm. The coloration is further reduced in addition to the effect of the addition of Sb ₂ 0 _3, was preferred. Even when Sb ₂ O ₃ was not added, the button flow diameter of Example 25 was 3 mm smaller than that of Example 24, and coloring was also reduced. Furthermore, in Examples 19, 20, and 25 to which titanium oxide was added, the expansion coefficient was not substantially changed by the addition, and other characteristics such as strength were not changed.

Further, using the glass material for sealing of Example 1, a glass container shown in the sectional view of FIG. 1 (b) was manufactured at a sealing temperature of 450 ° C. 13KV between the glass container 1 and the back plate glass 14
When a long-term durability test was performed by applying the voltage of No. 3, no particular abnormality occurred.

[0032]

When the attached glass material of the present invention is used, 4
It is possible to manufacture a container for a display tube by sealing the windshield container and the back plate material at the peripheral edge at a sealing temperature of 50 ° C. or less. Especially, when the front container glass is expansion coefficient similar composition to that or float glass soda-lime-silica composition 80 × 10 ^{over 7 / ℃ ~100 × 10 -7 /} ℃ is the front container glass and sealing glass Since the difference in expansion coefficient is small, it is possible to obtain a display tube having high pressure resistance.

[Brief description of drawings]

FIG. 1 is a view showing an example of a usage mode of the glass material for sealing of the present invention.

[Explanation of symbols]

1 ... Front container glass, 11 ... Display part, 12
... Side wall part, 13 ... Flange part, 2 ... Back plate glass, 3 ... Cathode ray tube container, 4 ... Sealing glass,
5 ... Electron gun unit, 6 ... Phosphor layer

Claims (2)

[Claims] 1. A sealing glass comprising a mixed powder of glass powder mixed with crystal powder of cordierite, lead titanate, zircon or titanium oxide, wherein the glass powder and the mixed powder have the following composition ratios. A characteristic glass material for sealing. Glass powder PbO: 75-85 wt% B ₂ O _3: 8~15 wt% SiO _2: 0.1 to 0.4 wt% ZnO: 2 to 6 wt% Al ₂ O _3: 1~8 wt% TiO ₂ : 0-3 wt% ZrO _2: 0 to 1.5 wt%, however, TiO ₂ + ZrO _2: 0~3 wt% Sb ₂ O _3: 0 to 2 wt% mixed powdered glass powder: 60 to 92 wt% zircon: 2 to 15 wt% Cordierite: 0 to 15 wt% Lead titanate: 0 to 25 wt% Titanium oxide: 0 to 5 wt% However, when cordierite and lead titanate are added, the total of these is 4 -25% by weight. _2. The composition ratio of TiO ₂ + ZrO _{2 in} the glass powder is 0.1 to 3% by weight, and the composition ratio of Sb ₂ O ₃ is 0.1 to ₂ %.
The composition ratio of titanium oxide in the mixed powder is 0.1% by weight.
The glass material for sealing according to claim 1, wherein the glass material for sealing is 5 wt%.