KR101020143B1 - Bismuth-based sealing material and bismuth-based paste material - Google Patents

Abstract

[PROBLEMS] To provide a bismuth-based sealing material that is substantially free of PbO and has good thermal stability, particularly in the manufacturing process of PDP, no devitrification or crystals are precipitated even after primary firing at about 500 ° C. To provide a bismuth-based sealing material that can be airtightly sealed in the secondary firing of 450 ~ 500 ℃.

[Solution] In a bismuth-based sealing material containing bismuth-based glass and a refractory filler, the refractory filler is represented by SiO _{2 in} terms of weight% of the following oxide equivalent. 30-100%, Al ₂ O ₃ 0-45%, ZnO 0-35%, ZrO ₂ 0-20%, TiO ₂ 0-20%, Li ₂ O 0-10%, MgO 0-25%, and the volume ratio of particles having a particle diameter of 5 μm or less in the refractory filler is 15-70%.

Bismuth Sealing Materials, Bismuth Paste Materials

Description

Bismuth-based sealing material and bismuth-based paste material {BISMUTH-BASED SEALING MATERIAL AND BISMUTH-BASED PASTE MATERIAL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to bismuth sealing materials suitable for sealing electronic components, flat panel displays, and the like, and more particularly to bismuth sealing materials suitable for sealing plasma display panels.

Conventionally, glass is used as sealing materials, such as an electronic component and a flat-panel display apparatus. Glass is excellent in chemical durability and heat resistance as well as airtightness, such as a display, compared with resin adhesive.

These glasses require various properties such as mechanical strength, fluidity, electrical insulation, etc., depending on the application, but they are required to be used at a temperature that does not deteriorate at least the fluorescent properties of phosphors used for flat display devices and the like. Therefore, lead boric acid-based glass (for example, see Patent Document 1) containing a large amount of PbO having a great effect of lowering the melting point of glass as a glass satisfying the above characteristics has been widely used.

By the way, the environmental problem is pointed out about the PbO contained in lead-boric-acid glass in recent years, and it is expected to switch from lead-boric-acid glass to glass which does not contain PbO. Therefore, various low melting glass is developed as a substitute of lead boric acid type glass. Among them, bismuth-based glass (also referred to as Bi ₂ O ₃ -B ₂ O ₃ -based glass) described in Patent Document 2 or the like has properties substantially equivalent to lead boric acid-based glass in various properties such as coefficient of thermal expansion. Although it is expected as an alternative candidate, it is still true that the characteristics such as flowability and thermal stability still fall short of the lead boric acid-based glass.

In general, the sealing material is a composite powder containing a glass powder and a refractory filler powder, and low-expansion lead titanate or the like has been used as the refractory filler. However, as in the case of glass, it is expected to replace the fire resistant filler also with the fire resistant filler which does not contain PbO. For example, Patent Literature 3 discloses a sealing material containing 50 to 95% by volume of lead-free low melting point glass powder and 5 to 50% by volume of zirconium tungsten phosphate powder, and using zirconium tungstate phosphate as a fire-resistant filler. Is disclosed.

By the way, the sealing material used for the plasma display panel (henceforth PDP) which is a flat display apparatus goes through the following heat processing processes.

First, a paste-like sealing material dispersed in a vehicle is applied to the vicinity of the outer circumference of the back plate panel of the PDP, and primary baking (also referred to as a glazing process and a plasticity process) is performed by thermal decomposition or incineration of the vehicle component at a high temperature. The vehicle for uniformly dispersing the sealing material contains an organic solvent or a resin. As the resin used in the vehicle, nitrocellulose or acryl resin which is thermally decomposed well at a temperature below the softening point of glass is generally used. The sealing material and the vehicle are uniformly dispersed using a kneading apparatus such as a three roll mill. The primary firing is carried out at a temperature condition at which the resin used for the sealing material is completely pyrolyzed, and if the resin is incompletely thermally decomposed, the resin is contained in the sealing material in a secondary firing (also referred to as a sealing process or a sealing process) that is then supplied. The residue of is left, and as a result, it is possible to cause a fatal defect in ensuring the airtightness of the PDP such as devitrification or bubbles in the sealing material.

Next, secondary baking of the sealing material is performed to seal the front plate panel and the back plate panel of the PDP. Finally, after evacuating the inside of the PDP through the exhaust pipe, the required amount of rare gas is injected to seal the exhaust pipe. In this way, a PDP is produced.

Patent Document 1: Japanese Patent Application Laid-Open No. 63-315536

Patent Document 2: Japanese Patent Application Laid-Open No. 2003-095697

Patent Document 3: Japanese Patent Publication No. 2005-35840

In patent document 2, the bismuth type glass composition which can be used for the use of sealing of electronic components, coating | cover, etc. is illustrated. However, this bismuth type glass composition has a high softening point compared with glass containing PbO, and lacks the fluidity of glass. Moreover, this bismuth type glass composition is inadequate in the thermal stability of glass, and cannot apply to the use through several heat processing processes.

If in order to decrease the softening point of the glass, it is necessary to increase the content of the Bi ₂ O ₃ main components, increasing the content of Bi ₂ O ₃ fluidity tends to be precipitated at the time of the determination that the Bi ₂ O ₃ as a component plastic It is easy to be damaged. Therefore, it is difficult to improve fluidity only by increasing the content of Bi ₂ O ₃ . On the other hand, when the content of Bi ₂ O ₃ is reduced, the thermal stability is improved, but the softening point is increased, thereby impairing the fluidity of the glass. Therefore, in bismuth type glass, it was difficult to make both the thermal stability and fluidity of glass compatible.

Moreover, the following technical problem also exists in the fire resistant filler used by adding to bismuth type glass.

Although there are various methods as a manufacturing method of a refractory filler, the method called the crystallization glass method is known, for example, this crystallization glass method melt | dissolves, shape | molds, and pulverizes the glass raw material combined so that it may have a desired chemical composition, and crystallized glass powder It is a method of calcining and calcining these after preparing. However, in such a method, it is necessary to regrind this because they are strongly sintered and sintered together in a sintering process of the crystalline glass powder and become agglomerates of hard crystals. It inevitably occurs. When such fine powder is present in the sealing material, the specific surface area of the refractory filler is increased, and as a result, the reaction area with the glass is increased, and the refractory filler is easily dissolved in the glass. When the refractory filler is dissolved in the glass, fine powder may act as crystal nuclei when firing the sealing material, which may impair the thermal stability of the glass. In addition, the refractory filler of patent document 3 is produced by carrying out wet mixing of raw material powder, baking on predetermined conditions, and grinding after obtaining the zirconium tungstate tungstate phosphate sintered compact. Since this refractory filler is ground by a ball mill, fine powder having a particle diameter of 0.5 μm or less is inevitably present in the refractory filler, and mixing this with bismuth-based glass impairs the thermal stability of the bismuth-based sealing material.

In the manufacturing process of the PDP, the primary firing of the phosphor material and the sealing material may be performed at the same time for the efficiency of the work. In general, when the primary firing temperatures of both materials are compared, the firing temperature of the phosphor material is higher and is about 480 to 500 ° C. Therefore, when the thermal stability of the sealing material is low, devitrification occurs at this temperature range (around 480 to 500 ° C), and fluidity at the subsequent secondary firing (450 to 500 ° C) is impaired and airtight sealing cannot be performed. there was.

Accordingly, an object of the present invention is to provide a bismuth-based sealing material having good thermal stability in a bismuth-based sealing material containing bismuth-based glass and a refractory filler, specifically, in the manufacturing process of PDP, at about 500 ° C. Even if primary firing, crystals do not precipitate in the glass and provide a bismuth-based sealing material that can be hermetically sealed well at secondary firing at 450 to 500 ° C.

As a result of intensive efforts, the inventors have found that in a bismuth-based sealing material containing bismuth-based glass and a refractory filler, the refractory filler is composed of SiO ₂ 30-100% and Al ₂ O ₃ 0-45 in terms of weight% of the following oxide conversion as a composition. %, ZnO 0-35%, ZrO ₂ 0-20%, TiO ₂ 0-20%, Li ₂ O 0-10%, MgO 0-25%, and in the refractory filler By regulating the proportion of the particles to 15 to 70%, the inventors have found that the above technical problem can be solved and propose as the present invention. Here, "particle diameter" and "particle ratio" are values computed by the measuring apparatus using the laser diffraction scattering method, and point out the value computed from the data of integrated particle size distribution. In addition, the refractory filler contains both crystals, such as a ceramic, and amorphous both, such as glass. When a refractory filler is a crystal | crystallization, it is judged that it is a refractory filler in accordance with this invention, if the component (crystal composition) of a crystal | crystallization is in the said range in conversion of weight%. In addition, not preclude the inclusion of components of the refractory filler is not described components, that is not specifically described components may be any component as in the _{ZrO 2, TiO 2, Li 2} O, MgO.

As a result of the intensive efforts, the inventors have limited the composition of the refractory filler to the above-mentioned composition range, and when the bismuth-based sealing material is fired, a part of the refractory filler is eluted into the bismuth-based glass, and the eluted component improves the thermal stability of the bismuth-based sealing material. Found to improve That is, the refractory filler in the composition range has a very good affinity with the bismuth-based glass, and does not impair the thermal stability of the bismuth-based sealing material even when fine powder in the refractory filler is eluted in the glass at the time of firing the bismuth-based sealing material. The thermal stability of the bismuth-based sealing material can be improved by actively dissolving fine powder present in the fire-resistant filler in the bismuth-based glass.

When the ratio of the particle | grains of 5 micrometers or less of particle | grains of a refractory filler is regulated to 15 to 70%, the elution amount of a refractory filler at the time of baking of a bismuth type sealing material can be regulated to an appropriate value. By setting the elution amount of the refractory filler to an appropriate value, it is possible to reliably improve the thermal stability of the bismuth-based glass. As a result, the bismuth type glass which lacks thermal stability compared with lead boric acid type glass as mentioned above can be improved to the thermal stability equivalent to or more than lead boric acid type glass. In particular, in the manufacturing process of a PDP, even if it bakes first at about 500 degreeC, a crystal | crystallization does not precipitate, and the bismuth type sealing material which can be airtightly sealed by secondary baking of 450-500 degreeC can be obtained. In other words, even if the content of Bi ₂ O _{3 which} is the main component of bismuth-based glass is increased, the crystal containing Bi ₂ O ₃ as a constituent does not precipitate at the time of firing, and the merit of increasing the content of Bi ₂ O ₃ is increased. Specifically, the effect of improving the fluidity of the bismuth-based sealing material can be precisely enjoyed.

In addition, when the ratio of the particle | grains whose particle diameter is 5 micrometers or less is controlled to 15 to 70%, it will not cause the fluidity | liquidity fall resulting from many fine powders. Therefore, it can be perfumed correctly, without impairing the low temperature sealing property inherent in a bismuth type sealing material. As a result, in the manufacturing process of the PDP, the bismuth-based sealing material of the present invention can satisfactorily seal the front plate glass and the back plate glass without the fluidity of the bismuth-based sealing material in the secondary firing at 450 to 500 ° C. Can be.

Secondly, the bismuth type sealing material of the present invention is characterized in that the specific surface area of the refractory filler is 0.5 to 4.0 m 2 / g. Here, "specific surface area" as used in this invention points out the value measured with the BET specific surface area measuring apparatus.

Third, the bismuth-based sealing material of the present invention is characterized in that the refractory filler is a crystal having cordierite as the main crystal.

4thly, the bismuth type sealing material of this invention is characterized by containing 40 to 95% of bismuth type glass and 5 to 60% of fire-resistant filler by volume% display.

The bismuth-based sealing material of the present invention is a bismuth-based glass is a glass composition in terms of mole% of the following oxide, Bi ₂ O ₃ 30-60%, B ₂ O ₃ 10-40%, ZnO 10-50% , BaO + SrO + MgO + CaO 0-15%, CuO 0-10%, Fe ₂ O ₃ 0-5%, SiO ₂ + Al ₂ O ₃ 0-15%, WO ₃ 0-5%, Sb ₂ O _It is characterized by containing ₃ 0-5%, In ₂ O ₃ + Ga ₂ O ₃ 0-5%.

In a sixth aspect, the bismuth-based sealing material of the present invention is characterized by substantially free of PbO. Here, in this invention, "it does not contain PbO substantially" refers to the case where content of PbO is 1000 ppm or less.

The bismuth-based sealing material of the present invention is characterized in that when the crystallization temperature of the bismuth-based glass is set to T ₁ (° C) and the crystallization temperature of the bismuth-based sealing material is set to T ₂ (° C), T ₂ -T _1? Characterized by satisfying the relationship of ° C. Here, the term "crystallization temperature" as used in the present invention refers to a temperature at which an exothermic peak due to crystal precipitation is detected in a differential thermal analysis (DTA) apparatus. In the differential thermal analysis, the temperature is raised to 10 ° C / min from room temperature, and the atmosphere is an air atmosphere. In addition, the bismuth type glass used for the measurement of T <_1> and T <_2> uses the same thing naturally.

The bismuth-based sealing material of the present invention is a bismuth-based sealing material containing bismuth-based glass and a refractory filler, wherein the refractory filler is 30 to 100% of SiO _{2 in} terms of weight% of the following oxides as a composition, and Al ₂ O. ₃ 0 to 45%, ZnO 0 to 35%, ZrO ₂ 0 to 20%, TiO ₂ 0 to 20%, Li ₂ O 0 to 10%, MgO 0 to 25%, and also 10% particles of the fire resistant filler diameter (D ₁₀₎ are characterized as being the 0.3 ~ 5.5㎛. Here, the "10% particle diameter (D _10)" is the particle diameter of the point to a value as measured by a laser diffraction method, the accumulated 10% particle volume.

9. The bismuth-based sealing material of the present invention is a bismuth-based sealing material containing bismuth-based glass and a refractory filler, wherein the refractory filler is a composition of SiO ₂ 30-100%, Al ₂ O in terms of weight% of the following oxide conversion. ₃ 0 to 45%, ZnO 0 to 35%, ZrO ₂ 0 to 20%, TiO ₂ 0 to 20%, Li ₂ O 0 to 10%, MgO 0 to 25%, and also 90% particles of the fire resistant filler The diameter D ₉₀ is characterized by being 8-45 μm. Here, "90% particle diameter (D ₉₀ )" points out the value measured by the laser diffraction method, and is a particle diameter which becomes 90% of an integrated particle amount.

The bismuth type sealing material of the present invention is characterized by being used for sealing an electronic component or a flat panel display device.

The bismuth sealing material of the present invention is characterized by being used for sealing PDP.

The bismuth type paste material of this invention is characterized by containing the said bismuth type sealing material, a solvent, and resin.

In the bismuth sealing material of this invention, the reason which limited the composition of the refractory filler as mentioned above is shown below.

SiO ₂ is a component that increases the thermal stability of the bismuth-based sealing material and decreases the coefficient of thermal expansion of the refractory filler, the content of which is 30 to 100% by weight, preferably 35 to 85% by weight, more preferably 40-70 weight%. When the content of SiO ₂ is less than 30% by weight, the effect of increasing the thermal stability of the bismuth-based sealing material is insufficient. Furthermore, SiO ₂ may be used alone as a refractory filler.

Al ₂ O ₃ is a component that lowers the coefficient of thermal expansion of the refractory filler, and the content thereof is 0 to 45% by weight, preferably 10 to 40% by weight. When the content of Al ₂ O ₃ is more than 45% by weight, crystals tend to precipitate on the glass in the sealing step.

ZnO is a component for promoting elution of the refractory filler in the sealing step, and the content thereof is 0 to 35% by weight, preferably 0 to 30% by weight. When the content of ZnO is more than 35% by weight, crystals tend to precipitate on the glass in the sealing step.

ZrO ₂ is a component for reducing the coefficient of thermal expansion of the refractory filler, and the content thereof is 0 to 20% by weight. When the content of ZrO ₂ be easily crystals were precipitated in the glass in the process of sealing large than 20% by weight.

TiO ₂ is a component for reducing the coefficient of thermal expansion of the refractory filler, and the content thereof is 0 to 20% by weight. If the content of TiO ₂ is apt to crystals were precipitated in the glass in the process of sealing large than 20% by weight.

Li ₂ O is a component for promoting elution of the refractory filler in the sealing step, and the content thereof is 0 to 10% by weight. When the content of Li ₂ O is more than 10% by weight is apt to crystals were precipitated in the glass.

MgO is a component for promoting the elution of the refractory filler after the sealing step, the content is 0 to 25% by weight, preferably 0 to 20% by weight, more preferably 10 to 20% by weight. When content of MgO is more than 25 weight%, crystal becomes easy to precipitate in glass in a sealing process.

Moreover, even another component can add up to 5 weight% in the range which does not impair the characteristic of a fire resistant filler.

In the bismuth sealing material of the present invention, both the glass and the crystal can be used as long as the refractory filler is within the above composition range, but the refractory filler of the crystal has a low coefficient of thermal expansion and can improve the mechanical strength of the bismuth sealing material. desirable. Moreover, when glass is used as a fire resistant filler, the elution amount of a fire resistant filler can be increased, and as a result, the effect of improving the thermal stability of the bismuth type sealing material after a sealing process becomes large.

The refractory filler according to the present invention is preferably one or two or more selected from crystals containing cordierite, β-quartz solid solution, zinc petalite, β-eucryptite, ganite and the like as the main crystals and quartz glass. Do. These refractory fillers are suitable because they have a low coefficient of thermal expansion and a large effect of improving the thermal stability of the bismuth-based sealing material. In particular, since the crystals containing cordierite as the main crystal have a good affinity with bismuth-based glass, the amount of the refractory filler is dissolved in the glass during the sealing process, and the effect of improving the thermal stability of the bismuth-based sealing material is large. rather, it is suitable since there is no being the precipitated crystals of the Bi ₂ O ₃ as a component in the process of sealing. Moreover, the fire resistant filler which has the said composition for the purpose of raising the mechanical strength etc. of glass, etc. Other refractory fillers (for example, tin oxide, zirconia, alumina, etc.) can be suitably added in the range which does not impair a characteristic.

In the fire resistant filler according to the present invention, the proportion of particles having a particle diameter of 5 μm or less as measured by laser diffraction scattering method is 15 to 70%, preferably 15 to 60%, more preferably 20 to 60%, More preferably, it is 25-50%. When the ratio of the particle | grains of 5 micrometers or less of particle diameters is less than 15%, when the bismuth type sealing material is baked, the amount of dissolution of the refractory filler will be reduced, and the effect of improving the thermal stability of the bismuth type sealing material becomes difficult to be obtained. When the proportion of particles having a particle diameter of 5 µm or less is greater than 70%, the dissolution of the refractory filler becomes excessive in the sealing step, resulting in insufficient fluidity of the bismuth-based sealing material. Particularly, in the manufacturing process of the PDP, the secondary at 450 to 500 ° C. In firing, the bismuth-based sealing material becomes difficult to soften and flow well, making it difficult to seal the faceplate panel and the backplate panel at low temperature.

In the fire resistant filler according to the present invention, the 10% particle diameter (D ₁₀ ) is 0.3 to 5.5 μm, preferably 0.5 to 4.0 μm, more preferably 1.0 to 3.5 μm. When the 10% particle diameter (D ₁₀ ) is less than 0.3 µm, the dissolution of the refractory filler becomes too large in the sealing step, resulting in insufficient fluidity of the bismuth-based sealing material, and particularly in the manufacturing process of the PDP, the secondary of 450 to 500 ° C. In firing, the bismuth-based sealing material is less likely to soften and flow well, making it difficult to seal the faceplate panel and the backplate panel at low temperature. In addition, it takes a long time for the pulverization of the refractory filler, and the production efficiency of the refractory filler is lowered. On the other hand, when the 10% particle diameter (D ₁₀ ) is larger than 5.5 μm, the amount of dissolution of the refractory filler becomes less, and it is difficult to obtain an effect of improving the thermal stability of the bismuth-based sealing material, and microcracks are formed in the sealing layer after the sealing step. It is easy to occur.

In the fire resistant filler according to the present invention, the 90% particle diameter (D ₉₀ ) is 8 to 45 µm, preferably 10 to 32 µm, more preferably 15 to 30 µm. If the 90% particle diameter (D ₉₀ ) is less than 8 µm, the dissolution of the refractory filler becomes too large in the sealing step, resulting in insufficient fluidity of the bismuth-based sealing material. Particularly, in the manufacturing process of the PDP, secondary firing at 450 to 500 ° C. In the bismuth-based sealing material, it is difficult to soften and flow well, making it difficult to seal the front panel and the back panel at low temperature. Moreover, the classification efficiency of a fire resistant filler falls. On the other hand, when the 90% particle diameter (D ₉₀ ) is larger than 45 µm, microcracks tend to occur in the sealing layer after the sealing step.

The larger the specific surface area of the refractory filler at the time of firing the bismuth-based sealing material, the larger the area in contact with the glass, and the greater the amount of the refractory filler dissolved in the glass. In the fire resistant filler according to the present invention, the specific surface area value measured by the BET specific surface area measuring apparatus is preferably 0.5 to 4.0 m 2 / g, more preferably 0.5 to 3.5 m 2 / g, and more preferably 0.6 to 2.3 m 2 / g. This is more preferable. When the specific surface area value of a refractory filler is larger than 4.0 m <2> / g, the quantity of the refractory filler melt | dissolved in glass at the time of baking of a bismuth type sealing material increases too much, and there exists a possibility that the fluidity of a bismuth type sealing material may be impaired. If the specific surface area of the fire resistant filler is less than 0.5 m 2 / g, the amount of the fire resistant filler dissolved in the glass during the firing of the bismuth-based sealing material decreases, and as a result, the effect of improving the thermal stability of the bismuth-based sealing material is obtained. Becomes difficult.

Bismuth-based glass powder in the case of sealing with bismuth-based glass and a material which is not suitable for the coefficient of thermal expansion, for example, high strain glass (85 × 10 ⁻⁷ / ° C.), soda plate glass (90 × 10 ⁻⁷ / ° C.) It is necessary to mix and refractory filler powder to make a composite material, and to make this a sealing material. It is important to design the coefficient of thermal expansion of the encapsulation material as low as 10 ~ 30 × 10 ^-7 / ℃ for the encapsulated material. This is to prevent deformation of the sealing layer by setting the deformation applied to the sealing layer after sealing to the compression (compression) side. In addition to adjusting the coefficient of thermal expansion, for example, a refractory filler powder may be added to improve the mechanical strength.

In the case of mixing the refractory filler powder, the mixing ratio is preferably 40 to 95% by volume of the bismuth-based glass powder and 5 to 60% by volume of the refractory filler powder, and 40 to 90% by volume of the bismuth-based glass powder and the refractory filler powder. It is more preferable that it is 10-60 volume%. The reason why these ratios are defined in this way is that when the refractory filler powder is less than 5% by volume, the effect of adding the refractory filler is difficult to be obtained, and when it exceeds 60% by volume, the fluidity becomes poor and airtight sealing cannot be performed. Because there is.

In addition, when the refractory filler powder is coated with fine powder such as alumina, zinc oxide, zircon, titania, zirconia, the reaction between the bismuth-based glass powder and the refractory filler powder can be suppressed. Therefore, when the refractory filler powder is coated with fine powder such as alumina, zinc oxide, zircon, titania, zirconia, the amount of the refractory filler powder can be controlled.

In the bismuth type sealing material of this invention, the reason which limited the glass composition of bismuth type glass as mentioned above is shown below.

Bi ₂ O ₃ is a main component for lowering the softening point. The content is 30-60 mol%, Preferably it is 35-55 mol%, More preferably, it is 35-50 mol%, More preferably, it is 35-45 mol%. When the content of Bi ₂ O ₃ is less than 30 mol%, the softening point of the glass becomes too high, and it becomes difficult to seal at a low temperature of 500 ° C or lower. On the other hand, when the content of Bi ₂ O ₃ is more than 60 mol%, the glass becomes thermally unstable, and the glass is easily devitrified at the time of melting or baking.

B ₂ O ₃ is a component for forming a glass network, the bismuth-based glass, the essential components. The content is 10-40 mol%, Preferably 12-35 mol%, More preferably, it is 15-30 mol%, More preferably, it is 15-25 mol%. When the content of B ₂ O ₃ is less than 10 mol%, the glass becomes thermally unstable, and the glass is easily devitrified at the time of melting or firing. On the other hand, B ₂ O ₃ is large, the viscosity of the glass increases excessively greater than 40 mol%, the content of it is difficult to sealing at a low temperature of less than 50 ℃.

ZnO is a component having an effect of suppressing devitrification at the time of melting or firing of glass. The content is 10-50 mol%, Preferably it is 12-45 mol%, More preferably, it is 15-40 mol%, More preferably, it is 20-35 mol%. When content of ZnO is less than 10 mol%, the effect which suppresses the devitrification at the time of melting of a glass, or baking is difficult to be acquired. When the content of ZnO is more than 50 mol%, there is a lack of balance in the glass composition, and consequently, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified.

BaO, SrO, MgO, and CaO have an effect of suppressing devitrification at the time of melting or baking glass. These components can be contained in a total amount of up to 15 mol%. When the total amount of these components is more than 15 mol%, the softening point of the glass becomes too high, making it difficult to seal at a low temperature of 500 ° C or lower.

1-10 mol% is preferable and, as for content of BaO, 2-6 mol% is more preferable. When content of BaO is less than 1 mol%, the effect which suppresses the devitrification at the time of melting or baking of glass becomes difficult to be obtained. When the content of ZnO is more than 10 mol%, there is a lack of balance in the glass composition, and consequently, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified.

0-5 mol% is preferable and, as for each content of SrO, MgO, CaO, 0-2 mol% is more preferable. When content of each component is more than 5 mol%, glass will become devitrification and powdering easily.

CuO has the effect of suppressing devitrification at the time of melting of a glass, or baking, and can add up to 10 mol%. When content of CuO is more than 10 mol%, glass will be devitrified easily and the fluidity of glass will be easy to be impaired.

Fe ₂ O ₃ has the effect of suppressing devitrification at the time of melting or sintering during the glass, the content thereof is preferably 0 to 5 mol%, more preferably 0.1 to 2 mol%. When the content of Fe ₂ O ₃ is more than 5 mol%, there is a lack of balance in the glass composition, on the contrary, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified.

SiO _2, Al ₂ O ₃ is a component for improving weather resistance of the glass. As for the content, 0-15 mol% is preferable in total, and 0-10 mol% is more preferable. When the total amount of these components is more than 15 mol%, the softening point of glass becomes too high and it becomes difficult to seal at low temperature below 500 ° C. In particular, the content of SiO ₂ is 0 to 10 mol% is preferred, more preferably 0 to 5 mol%. The content of Al ₂ O ₃ is preferably 0 to 5 mol%, more preferably 0 to 2 mol%.

WO ₃ is a component for suppressing devitrification of the glass, the content of which is preferably 0 to 5 mol%, more preferably 0 to 2 mol%. In the bismuth-based glass, in order to lower the softening point of the glass is determined to precipitate from the glass during the ground is necessary to increase the content of Bi ₂ O _3, more when the content of Bi ₂ O ₃ but sintering the flowability of the glass is inhibited. In particular, this tendency becomes remarkable when less than the content of Bi ₂ O ₃ 40 mol%. However, in bismuth-based glass, when WO ₃ is suitably added, even if the content of Bi ₂ O ₃ is 40 mol% or more, the thermal stability of the glass is less likely to be lowered. However, when the content of WO ₃ is more than 5 mol%, there is a lack of balance in the glass composition, on the contrary, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified.

Sb ₂ O ₃ is a component for inhibiting the devitrification of the glass, the content thereof is preferably 0 to 5 mol%, 0-2 mol% is more preferable. Sb ₂ O ₃ has an effect of stabilizing the network structure of bismuth-based glass, and by adding Sb ₂ O ₃ to bismuth-based glass appropriately, the thermal stability of the glass is lowered even if the content of Bi ₂ O ₃ is 40 mol% or more. Becomes difficult. However, when the content of Sb ₂ O ₃ is more than 5 mol%, there is a lack of balance in the glass composition, and conversely, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified.

_{In 2 O 3, Ga 2 O} 3 is an essential component, but, a component for inhibiting the devitrification of the glass, its content is in the range of 0 to 5 mol% in total amount is preferable, more preferably 0.1 to 3 mol%. In ₂ O ₃ and Ga ₂ O ₃ have an effect of stabilizing the network structure of bismuth-based glass, and the content of Bi ₂ O ₃ is 40 mol by appropriately adding In ₂ O ₃ and Ga ₂ O ₃ to the bismuth-based glass. Even if it is more than%, the thermal stability of glass will become difficult to fall. However, when the content of In ₂ O ₃ and Ga ₂ O ₃ is more than 5 mol%, the balance in the glass composition is insufficient, on the contrary, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified. In addition, the content of In ₂ O ₃ is 0 to 5 mol%, and more preferably, it is the content of Ga ₂ O ₃ is more preferably 0 to 2 mol%.

Oxides of Li, Na, K and Cs are components which lower the softening point of the glass, but are preferably 2 mol% or less in total because they have the function of promoting the devitrification of the glass at the time of melting.

P ₂ O ₅ is a component, but of suppressing devitrification at the time of melting is not preferred because it is easy to be added amount is more than 1 mol%, the glass phase separation in the melting.

MoO ₃ , La ₂ O ₃ , Y ₂ O ₅ , CeO ₂ and Gd ₂ O ₃ are components that suppress the phase separation of glass at the time of melting, but when the total amount is more than 3 mol%, the softening point of the glass becomes high and is 500 ° C. or less. It becomes difficult to bake at temperature.

Moreover, even if it is another component, it can add to 5 mol% in the range which does not impair the characteristic of glass.

Bismuth type glass which has the above glass composition is amorphous (amorphous) glass which shows favorable fluidity at the temperature of 500 degrees C or less, and the thermal expansion coefficient in 30-300 degreeC is about 100-120x10 <^-7> / ^degreeC .

Although the bismuth type sealing material of this invention does not exclude the form containing PbO, it is preferable that PbO does not contain substantially for environmental reasons as mentioned above. Further, if the glass contains PbO in some cases to be spread is Pb ^{2 +} present in the glass deteriorate the electrical insulating properties.

The bismuth-based sealing material of the present invention has a relationship of T ₂ -T ₁ ≥ 5 ° C when the crystallization temperature of the bismuth-based glass material is T ₁ (° C) and the crystallization temperature of the bismuth-based sealing material is T ₂ (° C). it is desirable to satisfy, and more preferably satisfies the relationship of T ₂ -T ₁ ≥7 ℃, it is more preferable to satisfy a relation of T ₂ -T ₁ ≥10 ℃. If T ₂ -T ₁ <5 ° C, the effect of improving the thermal stability of the bismuth-based sealing material becomes difficult to be obtained, and glass is easily devitrified when fired at 500 ° C for 30 minutes, for example.

It is preferable to use the bismuth sealing material of this invention for sealing an electronic component or a flat-panel display apparatus. Electronic components may use a member whose properties deteriorate at high temperatures. In that case, since the bismuth type sealing material of this invention can be sealed at low temperature, it does not deteriorate the characteristic of the member which lacks heat resistance, and is suitable. Moreover, even if sealing of an electronic component is performed at high temperature, since the bismuth type sealing material of this invention is excellent in thermal stability, devitrification of glass can be suppressed in a sealing process. If the flat display device can be sealed at a low temperature as much as possible, the manufacturing efficiency can be improved, and the deterioration of other members such as phosphors can be prevented. Since the bismuth sealing material of this invention can be sealed at low temperature, it is suitable for a flat panel display device. In addition, the bismuth-based sealing material of the present invention is excellent in thermal stability even when the flat display device is sealed at a high temperature, so that devitrification of glass can be prevented in the sealing step.

It is preferable to use the bismuth type sealing material of this invention for sealing of PDP. Since the bismuth-based sealing material of the present invention does not precipitate crystals even when the primary firing is performed at about 500 ° C. in the manufacturing process of the PDP, the bismuth sealing material can be satisfactorily sealed at the secondary firing at 450 ° C. to 500 ° C., so that the PDP It can contribute to the improvement of manufacturing efficiency and the improvement of properties.

Although the sealing material which mixed bismuth type glass powder and fire-resistant filler powder may be used as a sealing material in the state of powder, it is easy to handle when the sealing material and vehicle are uniformly kneaded and used as a paste. The vehicle consists mainly of an organic solvent and a resin, and the resin is added for the purpose of adjusting the viscosity of the paste. Moreover, surfactant, a thickener, etc. can also be added as needed. The prepared paste is applied using an applicator such as a dispenser or a screen printing machine.

Examples of the organic solvent include N, N'-dimethylformamide (DMF), α-terpineol, higher alcohols, γ-butyllactone (γ-BL), tetralin, butyl carbitol acetate, ethyl acetate, isoamyl acetate, Diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, benzyl alcohol, toluene, 3-methoxy-3-methylbutanol, water, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, dipropylene glycol monomethyl Ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, propylene carbonate, dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone and the like can be used. In particular, α-terpineol is preferable because of its high viscosity and good solubility such as resin.

As the resin, acrylic resin, ethyl cellulose, polyethylene glycol derivatives, nitro cellulose, polymethyl styrene, polyethylene carbonate, methacrylic acid ester and the like can be used. In particular, acrylic resins and nitrocelluloses are preferred because of their good thermal decomposition.

Example 1

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on an Example.

Each sample (A-O) of Tables 1-3 was prepared as follows.

First, the glass batch which combined the raw materials, such as various oxides and carbonates, was prepared so that it might become the glass composition shown in Tables 1-3, it put in the platinum crucible and melted at 900-1000 degreeC for 1-2 hours. Next, a part of molten glass was sent to the metal mold | die made as a sample for a push-type thermal expansion measurement (TMA) apparatus, and the other molten glass was shape | molded in flake shape by the water cooling roller. In addition, the sample for thermal expansion coefficient measurement performed predetermined slow cooling process (annealing) after shaping | molding. Finally, the flake-shaped glass was pulverized with a ball mill and passed through a sieve of 75 mu m in diameter to obtain each sample having an average particle diameter of about 10 mu m.

The thermal expansion coefficient, glass transition point, softening point, and devitrification state were evaluated using the above sample. The results are shown in Tables 1-3.

Softening point was calculated | required by the differential thermal analysis (DTA) apparatus using the powder sample.

The glass transition point and the coefficient of thermal expansion were obtained by TMA apparatus. The thermal expansion coefficient was measured in the temperature range of 30-300 degreeC.

The samples (A to O) of Tables 1 to 3 evaluated the devitrification state by visually observing the surface crystals of the samples using an optical microscope (100x magnification) after maintaining the powder press-formed body in a firing furnace at 500 ° C for 30 minutes. "(Circle)" that the devitrification was not confirmed was made into "x" that the devitrification was confirmed. In addition, the temperature increase / speed rate was 10 degree-C / min.

The samples (A-M) of Tables 1-3 had a glass transition point of 335-375 degreeC, a softening point of 392-442 degreeC, and had low melting-point characteristic. In addition, samples A-M had a thermal expansion coefficient of 103-119x10 <^-7> / degreeC. Moreover, evaluation of the devitrification state was favorable for the samples A-M, and were equipped with favorable thermal stability.

The sample N of Table 3 had a glass transition point of 389 degreeC and a softening point of 480 degreeC, and was high melting | fusing point compared with the glass sample of an Example. The sample (O) of Table 3 had poor evaluation of the devitrification state, and lacked thermal stability.

The glass powder samples (A-M) of Tables 1-3 and the predetermined fire-resistant filler powder in the table were mixed, and the bismuth type sealing material shown in Tables 4-6 was obtained. Samples No. 1 to 10 of Tables 4 and 5 represent examples, and Samples No. 11 to 15 of Table 6 show comparative examples. The thermal expansion coefficient, the softening point, the flow diameter, and the thermal stability of the samples (Nos. 1 to 15) were evaluated. In addition, the thermal expansion coefficient and the softening point were measured by the same method as the case of the said glass sample.

The fire resistant filler powder used for the bismuth type sealing material shown to Tables 4-6 was produced as follows. Willemite is combined with zinc oxide, pure silicon, aluminum oxide in a weight percent of 70% ZnO, 25% SiO ₂ , and 5% Al ₂ O ₃ , and then calcined at 1440 ° C. for 15 hours after mixing. Was ground to obtain a powder having a predetermined particle size. Cordierite combines magnesium oxide, aluminum oxide and pure silicon in a ratio of 2MgO.2Al ₂ O ₃ .5SiO ₂ , and after mixing, calcining at 1400 ° C. for 10 hours, and then pulverizing the fired product to obtain a predetermined particle size. Powder was obtained. β- -eucryptite is SiO ₂ 74.3, and mixing the batch composition so that the weight%, Al ₂ O ₃ 21.0% by weight, Li ₂ O 1.7% by weight, was melted at 1650 ℃ 3 hours. Subsequently, predetermined crystal nuclei were added after fusion of the molten glass, and the fired product obtained after firing at 1100 ° C. for 7 hours was pulverized to obtain a powder having a predetermined particle size. β-quartz solid solution is 46.5% by weight of SiO ₂ , 23.3% by weight of Al ₂ O _3, 23.3% by weight of ZnO, ZrO ₂ The batch components were mixed so as to be 6.9% by weight, and melted at 1550 ° C for 3 hours. Subsequently, predetermined crystal nuclei were added after melting glass pulverization, and the baked material obtained after baking for 2 hours at 900 degreeC was pulverized and the powder which has a predetermined particle size was obtained. Zirconium phosphate is ₁₂ · 8H ₂ O and crushed ZrOC the fired product obtained after the firing of an aqueous solution of phosphoric acid to precipitate after mixed with a predetermined molar ratio at 1400 ℃, classified to obtain a powder having a desired particle size of the.

The particle size distribution of the fire resistant filler was measured by the measuring apparatus (SALD2000 by Shimadzu Corporation) which used the laser diffraction scattering method.

The specific surface area of the fire resistant filler was measured by the BET specific surface area measuring device.

The flow diameter is dry pressed into a button shape having an outer diameter of 20 mm by means of a mold with a powder having a weight corresponding to the synthesis density of each sample, which is loaded onto a high strain glass substrate having a thickness of 40 mm x 40 mm x 2.8 mm, and air. It heated and heated at the speed of 10 degree-C / min, and after baking at the baking conditions of Tables 5-8, it evaluated by measuring the diameter of the button obtained by temperature-falling to 10 degreeC / min to room temperature. In addition, a synthetic density is a theoretical density computed by mixing the density of glass and the density of a refractory filler in a predetermined volume ratio. Moreover, when a flow diameter is 19 mm or more, it means that it can seal favorably on the baking conditions tested.

Thermal stability indicates the value of when the crystallization temperature of the crystallization temperature of bismuth-based glass as T ₁ (℃), and bismuth-based sealing material as _{T 2 (℃) ΔT = T} 2 -T 1. In addition, a crystallization temperature refers to the temperature which the exothermic peak by crystal precipitation is detected with a differential thermal analyzer. In addition, differential thermal analysis heats up at 10 degree-C / min from room temperature, and atmosphere is an air atmosphere. When ΔT> 0, it means that the thermal stability of the bismuth-based sealing material is improved by the addition of the refractory filler. When ΔT <0, it means that the thermal stability of bismuth type glass deteriorated by addition of a fire resistant filler.

The samples (Nos. 1 to 10) of Tables 4 and 5 had a softening point of 402 to 445 ° C, and had a low melting point characteristic of flowing well at a temperature of 500 ° C or less. In addition, the samples (No. 1 to 10) had a coefficient of thermal expansion of 66.7 to 72.0 × 10 ⁻⁷ / ° C. and had a coefficient of thermal expansion suitable for high strain glass or the like. In addition, the samples (Nos. 1 to 10) had a low-melting point characteristic such that the flow diameter was 19.5 to 21.5 mm under the firing conditions in the table, and that they could be sealed at a temperature of 500 ° C or lower. In addition, the sample (No. 1-10) of Tables 4 and 5 has (DELTA) T 7-26 degreeC, and the thermal stability of the bismuth type sealing material improved by addition of a fire resistant filler.

The samples (Nos. 11 to 15) of Table 6 had a softening point of 391 to 434, a coefficient of thermal expansion of 67.1 to 73.3 × 10 ⁻⁷ / ° C., and a flow diameter of 20.5 to 21.5 mm under predetermined firing conditions in the table. However, since samples (No. 11-14) did not regulate the composition of a refractory filler in the predetermined range, (DELTA) T was -13--6 degreeC, and the thermal stability of bismuth type glass worsened by addition of a refractory filler. Since sample No. 15 did not regulate the ratio of the particle | grains of 5 micrometers or less in a refractory filler to a predetermined range, (DELTA) T turns into a small value as 4 degreeC, and the thermal stability of a bismuth type sealing material is improved by addition of a refractory filler. Not much improved.

As apparent from the above description, since the bismuth-based sealing material of the present invention can obtain good fluidity over a wide range of temperatures, it is used for other applications, that is, sealing of electronic components and flat display devices subjected to a plurality of heat treatment steps. In addition, the present invention can cope with the coating and the like accurately, and can also cope with the sealing and coating of the electronic component and the flat display device subjected to the high temperature heat treatment process. Specifically, the bismuth-based sealing material of the present invention is used for sealing a flat display device such as a field emission display (FED), for sealing a display such as a cathode ray tube (CRT), a fluorescent display tube (VFD), or a PDP. It is suitable for the formation of an insulating dielectric layer, the use of barrier ribs in PDPs, the use of magnetic head-cores or the sealing of cores and sliders, and the sealing of electronic components such as quartz crystal oscillators and IC packages.

Claims (12)

In a bismuth-based sealing material containing bismuth-based glass and a fire resistant filler: The bismuth-based glass is represented by the mole% in the following oxide conversion as a glass composition: Bi ₂ O ₃ 30 to 60%, B ₂ O ₃ 10 to 40%, ZnO 10 to 50%, BaO + SrO + MgO + CaO 0 to 15 %, CuO 0-10%, Fe ₂ O ₃ 0-5%, SiO ₂ + Al ₂ O ₃ 0-15%, WO ₃ 0-5%, Sb ₂ O ₃ 0-5%, In ₂ O ₃ + Ga ₂ O ₃ 0-5%, The refractory filler is a crystal in which cordierite is precipitated, and as a composition, SiO ₂ 30 to 100%, Al ₂ O ₃ 0 to 45%, ZnO 0 to 35%, ZrO ₂ 0 to 20%, TiO ₂ 0-20%, Li ₂ O 0-10%, MgO 0-25%, and the proportion of particles having a particle diameter of 5 μm or less in the refractory filler is 15-70%. Bismuth-based sealing material. The bismuth-based sealing material according to claim 1, wherein the specific surface area of the fire resistant filler is 0.5 to 4.0 m 2 / g. delete The bismuth-based sealing material according to claim 1 or 2, wherein the bismuth-based sealing material contains 40 to 95% of bismuth-based glass and 5 to 60% of a refractory filler in the volume% display. delete The bismuth-based sealing material according to claim 1 or 2, which does not contain PbO. The method of claim 1 or 2, wherein the bismuth-based crystallization temperature to the crystallization temperature of T ₁ (℃) and the bismuth-based sealing material of the glass when a T ₂ (℃) T ₁ -T ₂ of ≥5 ℃ A bismuth sealing material characterized by satisfying the relationship. The bismuth-based sealing material according to claim 1 or 2, wherein the 10% particle diameter (D ₁₀ ) of the refractory filler is 0.3 to 5.5 µm. The bismuth-based sealing material according to claim 1 or 2, wherein the 90% particle diameter (D ₉₀ ) of the refractory filler is 8 to 45 µm. The bismuth sealing material according to claim 1 or 2, which is used for sealing an electronic component or a flat panel display device. The bismuth sealing material according to claim 1 or 2, which is used for sealing a plasma display. The bismuth type sealing material of Claim 1 or 2, a solvent, and resin are contained, The bismuth type paste material characterized by the above-mentioned.