JPH11106235A - Composition for sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing composition capable of densely sealing at a relatively low sintering temperature by using glass powder having a composition of PbO, B2 O3 , ZnO, SiO2 , Al2 O3 , Bi2 O4 , CuO and F in specific amounts, respectively, and specifying a cuprous ion/(cuprous ion + cupric ion) molar ratio in the glass. SOLUTION: This composition for sealing comprises glass powder having a composition comprising 70-80 wt.% of PbO, 5-12 wt.% of B2 O3 , preferably a B2 O3 /PbO ratio of >=0.12, 2-10 wt.%, preferably 3-6 wt.%, of ZnO, 0.5-3 wt.%, preferably 1-2 wt.%, of SiO2 , 0-2.0 wt.%, preferably 0-1.0 wt.%, of Al2 O3 , 3.0-7.0 wt.% of BiO3 , 0.5-5.0 wt.%, preferably 1-2 wt.%, of CuO, and 0.1-6.0 wt.%, preferably 1-5 wt.%, of F, and has a Cu<+> /(Cu<+> +Cu<2+> ) molar ratio of >=50%, preferably >=60%, in the glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing composition, and more particularly to a sealing composition used for low-temperature sealing of various kinds of glass for display, soda lime lime glass, electronic parts and the like.

[0002]

2. Description of the Related Art Heretofore, low melting point glass has been used for sealing various display materials such as cathode ray tubes and for sealing alumina packages for ICs. Generally, PbO-B ₂ O ₃ system, PbO-B ₂ O ₃ -ZnO-based low melting glass is often used. These glasses have large expansion coefficients and often do not match well with those of the materials to be sealed. Thus, by mixing a low-expansion filler (inorganic crystal filler) with the low-melting glass, the expansion coefficient has been successfully reduced while maintaining properties such as low-temperature adhesion.

[0003] US Patent Nos. 3,250,631 and 325
No. 8350, JP-A-49-24208 and the like are typical examples thereof, and β-eucryptite, β
It discloses the addition of spodumene, lead titanate, quartz, zircon and the like. Further, many other proposals have been made in which the glass composition and the type and amount of the filler are changed in accordance with the respective purposes so as to correspond to various uses.

JP-A-52-56867 discloses a low-melting glass containing cordierite or lead titanate as a filler for hermetic coating and surface stabilization of a semiconductor device. It has good chemical resistance to the bath. Also,
Japanese Patent Publication No. 54-23928 discloses a material which is suitable for hermetically sealing a semiconductor element by adding lead titanate and zircon to a low melting glass, and which is not particularly immersed in an acid in a lead wire plating step. ing.

JP-B-61-43298, JP-A-56-43980
No. 69242 discloses PbO—B ₂ O ₃ —Zn as a low-melting glass suitable for sealing an alumina package for IC.
There is disclosed an O-SiO ₂ (—Al ₂ O ₃ —RO—SnO ₂ —R ₂₀ ) -based low-melting glass to which a filler such as cordierite is added. Furthermore, Japanese Patent Publication No. Sho 62-478
The No. 24, by adding zircon _{PbO-B 2 O 3 -SiO 2} -Al 2 O 3 based low-melting glass, the sealing glass of the display tube, not blackened even under the application of the DC voltage It has been disclosed.

[0006]

The glass used for flat displays and fluorescent display tubes is soda-lime glass or glass having a composition similar thereto, and has an expansion coefficient of about 80-100 × 10 ^-7 / ° C. Often.
Sealing is often performed in a temperature range of 430 to 550 ° C, but firing is preferably performed at a low temperature in order to perform bonding in a short time, and sealing glass that can be sealed at 400 ° C or lower is preferable. However, conventional sealing glass using PbO—B ₂ O ₃ or PbO—ZnO—B ₂ O ₃ glass is not enough to perform dense sealing at a low temperature of 400 ° C. or lower. Met.

[0007] An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a sealing composition capable of dense sealing at a firing temperature of 400 ° C or less.

[0008]

Means for Solving the Problems The present invention may display in weight%, PbO: 70~80%, B 2 O 3: 5~12%, ZnO: 2~10%, SiO 2: 0.5 ３3%, Al ₂ O ₃ : 0 to 2.0%, Bi ₂ O ₃ : 3.0 to 7.0%, CuO: 0.5 to 5.0%, F: 0.1 to 6.0% %, And a molar ratio of Cu ⁺ / (Cu ⁺ + Cu ²⁺ ) in the glass is 50% or more.

Here, the sealing composition is a mixture of the glass powder and the crystal powder, and the mixing ratio of the glass powder and the crystal powder is expressed in terms of% by weight.
Preferably it is 0 to 50%.

Further, in the sealing composition, it is preferable that the crystal powder is made of one or more of lead titanate, cordierite, zircon, willemite, silica, and alumina.

[0011]

Next, the reasons for limiting the composition of the sealing composition of the present invention will be described. However, the following compositions are expressed by weight%.

PbO is the most important component for lowering the melting point of glass. If the content of PbO is more than 80%, the glass tends to be devitrified, and the water resistance and the moisture resistance also deteriorate. If the content of PbO is less than 70%, the softening point of the glass becomes high,
It becomes difficult to seal below ℃.

When the content of B ₂ O ₃ is more than 12%, the softening point of the glass becomes high, so that sealing at 400 ° C. or lower becomes difficult. On the other hand, if B ₂ O ₃ is less than 5%, the glass tends to be devitrified. Preferably, B ₂ O ₃ / Pb is used in view of glass stability.
The ratio of O is set to be in the range of 0.12 or more.

If ZnO exceeds 10%, the crystallization rate during frit firing becomes too high, and the fluidity deteriorates. Further, if ZnO is less than 2%, water resistance and moisture resistance deteriorate,
Strength is also reduced. Preferably it is in the range of 3-6%.

If the content of SiO ₂ is more than 3%, the fluidity as a frit deteriorates, and at the same time, the strength of the sealing material decreases.
On the other hand, if the content of SiO ₂ is less than 0.5%, crystallization tends to take place during firing, and the fluidity deteriorates. In addition, the water resistance and the moisture resistance also deteriorate. Preferably it is in the range of 1-2%.

Al ₂ O ₃ is a component that stabilizes glass and improves water resistance and moisture resistance. However, if the content is more than 2.0%, the softening point of the glass increases and the glass tends to devitrify.
Preferably, it is in a range of 1.0% or less.

Bi ₂ O ₃ is a component effective for lowering the melting point of glass, similarly to PbO. If the content of Bi ₂ O ₃ is more than 7.0%, the glass tends to be devitrified, and the water resistance and the moisture resistance also deteriorate. On the other hand, if the content of Bi ₂ O ₃ is less than 3.0%, the softening point of the glass increases, and it becomes difficult to seal the glass at 400 ° C. or lower.

CuO is an effective component for lowering the softening point without significantly increasing the expansion coefficient of the glass and improving the fluidity, and also improves the water resistance and the moisture resistance. When CuO is higher than 5.0%, the softening point of the glass increases, and the glass tends to devitrify. In addition, CuO is 0.1.
If less than 5%, the effect is small. Preferably it is in the range of 1-2%.

The copper ions are preferably present in the glass, particularly in the form of monovalent ions Cu ⁺ , which makes it possible to simultaneously improve the fluidity of the glass and suppress the increase in the coefficient of thermal expansion. For this reason, the melting conditions, the amount of the oxidizing agent, and the amount of the reducing agent during the glass production are selected so that the molar ratio of Cu ⁺ / (Cu ⁺ + Cu ²⁺ ) becomes 50% or more. In particular, Cu ⁺ / (C
The molar ratio of ⁽ u ⁺ + Cu ²⁺ ) is preferably 60% or more.

F is a component that improves the fluidity of the glass. If F is less than 0.1%, the effect is small, and 6.0%
If it exceeds, the durability of the glass decreases. Preferably 1 to
The range is 5%.

Crystal powder is a material necessary for adjusting (decreasing) the expansion coefficient of glass. Lead titanate,
If the total of one or more of cordierite, zircon, willemite, silica, and alumina is less than 20%, the effect is small, and if it is more than 50%, the fluidity is low.

For normal sealing to various kinds of display glass, soda lime lime glass, electronic parts, etc., a vehicle (a material obtained by dissolving nitrocellulose in an isoamyl acetate solution) is used for the sealing material obtained in the present invention. Are mixed in an appropriate amount, and the sealing glass obtained in the form of a paste is applied to the adhesive surface and used.

[0023]

Embodiments of the present invention will be described below with reference to specific examples.

(Examples 1 to 6) Raw materials prepared so as to have the composition shown in Table 1 were put in a platinum crucible, and were heated at 1000 to 1200 ° C.
And melted. After melting for about 1 to 2 hours, the molten glass was crushed with water and crushed with a ball mill to 100 μm or less to obtain glass powder. Next, 100 μm was added to this glass powder.
The filler (inorganic crystal filler) pulverized to a particle size of m or less was added and homogeneously mixed to obtain a sealing material of this example.

Table 1 shows the molar ratio of Cu ⁺ / (Cu ⁺ + Cu ²⁺ ) and the mixing ratio of the filler (expressed in% by weight). In addition, the button flow diameter, residual stress, thermal expansion coefficient, and transition point of the sealing glasses of Examples 1 to 6 were measured. Table 1 shows the results.

[0026]

[Table 1]

Each of the above characteristics was evaluated as follows. [Button flow diameter] Glass powder 8 with the composition ratio shown in Table 1
g was weighed and press-molded into a column having a diameter of 12.5 mm (press pressure: about 100 kg / cm ² ). Next, the pressed glass powder was placed on a soda-lime glass plate (substrate glass) and baked at 400 ° C. for 30 minutes to obtain a sample. The sample softened and flowed, and spread almost like a disk. The diameter of this disk was used as the flow diameter, and was used as a measure of fluidity. When the flow diameter was 20 mm or more, it was determined that the material had sufficient fluidity.

[Residual Stress] The sample used for measuring the button flow diameter was cut, and the residual stress on the substrate glass side of the sample was measured using a polarimeter. This residual stress is due to the temperature at which the sealing glass adheres to the sample (usually near the glass transition point) and the difference in expansion between the sealing glass and the substrate glass from that temperature to room temperature. It is desirable that the stressed state is obtained because the sealing glass side becomes a compressive stress and the overall strength is improved. Since the values shown in Table 1 are positive when the substrate glass side has a compressive stress, a negative value means that the substrate glass side has a tensile stress, that is, the sealing glass side has a compressive stress.

[Coefficient of Thermal Expansion and Transition Point] A sample was prepared from the fired sealing material, and the thermal expansion was measured to determine the transition point and the average coefficient of thermal expansion from 30 ° C. to the transition point. When the sealing material is baked, it usually adheres at a temperature near the transition point when the temperature is lowered, so that a residual stress is generated due to a difference in expansion between the temperature and room temperature.

Examples 1 to 6 are sealing materials having a glass composition and a filler ratio within the scope of the present invention. In each example, sufficient fluidity, moderate residual stress, low coefficient of thermal expansion and low transition point were obtained.

(Comparative Example 1) A glass composition, a filler ratio, and a button according to a comparative example manufactured in the same manner as in Examples 1 to 6 except that the molar ratio of Cu ⁺ / (Cu ⁺ + Cu ²⁺ ) was changed. Table 1 shows the flow diameter, residual stress, coefficient of thermal expansion, and transition point.

As is clear from Table 1, the sealing material of Comparative Example 1 is easily crystallized as compared with the sealing material according to the present invention, so that the fluidity of the glass is low and the thermal expansion coefficient is large. The properties according to the examples have not been obtained. further,
Similarly, the characteristics according to the present example were not obtained for the residual stress and the transition point.

[0033]

As described in detail above, according to the sealing composition of the present invention, various kinds of glass for display and soda-lime glass can be sealed at a low temperature of 400 ° C. or lower.

Also, by changing the mixing ratio of the glass powder and the crystal powder, a desired coefficient of thermal expansion can be obtained, so that it is suitable for sealing various electronic parts.

Claims (3)

[Claims] 1. PbO: 70 to 80%, B ₂ O ₃ : 5 to 12%, ZnO: 2 to 10%, SiO ₂ : 0.5 to 3%, Al ₂ O ₃ : 0 to 2.0%, Bi ₂ O ₃ : 3.0 to 7.0%, CuO: 0.5 to 5.0%, F: 0.1 to 6.0% And a molar ratio of Cu ⁺ / (Cu ⁺ + Cu ²⁺ ) in the glass of 50% or more. 2. The glass powder according to claim 1, comprising a mixture of the glass powder and the crystal powder, wherein the mixing ratio of the glass powder and the crystal powder is represented by 50% by weight and 20 to 50% by weight. Sealing composition. 3. The sealing composition according to claim 1, wherein the crystal powder comprises at least one of lead titanate, cordierite, zircon, willemite, silica, and alumina.