JP5397583B2 - Bismuth glass composition and sealing material - Google Patents

Description

  The present invention relates to sealing of a flat display device such as a plasma display panel (hereinafter referred to as PDP), an organic EL display, a field emission display (hereinafter referred to as FED), a fluorescent display tube (hereinafter referred to as VFD), a piezoelectric vibrator package, and an IC package. The present invention relates to a bismuth-based glass composition and a sealing material suitable for sealing electronic parts such as the above.

  Conventionally, glass is used for sealing materials such as displays. Glass is excellent in chemical durability and heat resistance as compared with a resin-based adhesive, and is suitable for securing airtightness of a display or the like.

  These glasses are required to be usable at a temperature that does not deteriorate components used in displays and the like. Therefore, as a glass that satisfies the above characteristics, lead borate glass containing a large amount of PbO (for example, see Patent Document 1) has been widely used. However, lead borate glass has been pointed out to have environmental problems with respect to PbO as a main component.

Under such circumstances, it is desired to replace lead borate glass with lead-free glass, and various lead-free glasses have been developed as substitutes for lead borate glass. Among lead-free glasses, bismuth glass (Bi ₂ O ₃ —B ₂ O ₃ glass) has almost the same properties as lead borate glass, such as chemical durability and mechanical strength. (See, for example, Patent Document 2).
Japanese Unexamined Patent Publication No. Sho 63-315536 JP 2000-128574 A

  Patent Document 2 discloses a bismuth-based glass that can be used for sealing electronic components. However, since this bismuth-based glass has a higher softening point and lower fluidity than lead borate-based glass, it has a high sealing temperature. In particular, when the main firing temperature (sealing temperature, secondary firing temperature) is 450 to 500 ° C., the bismuth glass described in Patent Document 2 has low fluidity.

In order to increase the fluidity of the bismuth glass, it is necessary to increase the content of Bi ₂ O ₃ which is a component that lowers the softening point. However, when the content of Bi ₂ O ₃ is increased, crystals containing Bi ₂ O ₃ as constituent components are likely to precipitate during firing, and the fluidity tends to decrease. In particular, when the pre-baking temperature (primary baking temperature, glaze temperature) is about 500 ° C., the tendency becomes remarkable. Therefore, in bismuth-based glass, the fluidity cannot be increased simply by increasing the content of Bi ₂ O ₃ in the glass composition.

  In view of the above circumstances, the present invention provides a bismuth-based glass composition that can be sealed at 450 to 500 ° C. even if pre-baked at about 500 ° C., and does not easily crystallize on the glass and does not contain PbO. And to create a sealing material.

As a result of intensive studies, the present inventors have introduced SnO ₂ into the glass composition of bismuth-based glass in an amount of 0.3 to 5 mol%, thereby increasing the Bi ₂ O ₃ content. The present inventors have found that it is difficult for crystals to precipitate on glass, and propose as the present invention. That is, the bismuth-based glass composition of the present invention has a glass composition of mol% in terms of the following oxides: Bi ₂ O ₃ 32 to 50%, B ₂ O ₃ 10 to 40%, ZnO 10 to 29%, SnO ₂ 0.3 to 5%, MgO + CaO + SrO + BaO (total amount of MgO, CaO, SrO and BaO) 0 to 20% , CuO 0.1 to 10% .

The bismuth-based glass composition of the present invention contains 0.3 to 5 mol% of SnO _{2 in the} glass composition. In this _way, Bi ₂ glass network _{O 3 -B} 2 O 3 is stabilized, the temporary baking process, and _Bi 2 _{O 3} formed by bismuth oxide alone (Bisumaito), _Bi 2 _{O 3} and _{B 2 2Bi} 2 _O are formed by _{O 3 3 ·} B 2 O ₃ or _{12Bi 2 O 3 · B 2 O} 3 is less likely to precipitate.

The bismuth-based glass composition of the present invention preferably contains 0.1 to 15% of CuO + Fe ₂ O ₃ (total amount of CuO and Fe ₂ O ₃ ). If it does in this way, the devitrification resistance of glass can further be improved.

The bismuth-based glass composition of the present invention preferably contains 1 to 15% of BaO. If it does in this way, the devitrification resistance of glass can further be improved.

The bismuth-based glass composition of the present invention preferably contains substantially no PbO. Here, “substantially no PbO” refers to the case where the content of PbO in the glass composition is 1000 ppm (mass) or less. In this way, environmental demands in recent years can be satisfied.

The bismuth-based glass composition of the present invention is preferably used for sealing or coating.

The sealing material of the present invention is a sealing material containing a glass powder and a refractory filler powder. The glass powder comprising the bismuth-based glass composition is 50 to 100% by volume, and the refractory filler powder is 0 to 50% by volume. It is preferable to contain. In this way, the thermal expansion coefficient of the sealing material can be lowered so as to match the thermal expansion coefficient of the object to be sealed. In addition, the sealing material of this invention may be comprised only with glass powder, without adding a refractory filler powder.

In the sealing material of the present invention, the refractory filler powder is one or more kinds selected from willemite, cordierite, zircon, β-eucryptite, quartz glass, alumina, mullite, and alumina-silica ceramics. It is preferable .

Sealing material of the present invention, it is preferable crystallization temperature is 550 ° C. or higher. Here, the “crystallization temperature” refers to a temperature at which a crystallization peak appears in differential thermal analysis (DTA, in the air, temperature rising rate 10 ° C./min, measurement started from room temperature). If it does in this way, it will become difficult to produce devitrification in glass by a temporary baking process and a main baking process, and it can raise the manufacture yield of a flat display device etc.

The sealing material of the present invention is preferably used for a PDP or an organic EL display.

  In the bismuth-based glass composition of the present invention, the reason why the content ranges of the respective components are specified as described above will be described below. In addition, the following% display points out mol% unless there is particular notice.

Bi ₂ O ₃ is a main component for lowering the softening point, and its content is 32 to 50%, preferably 32 to 45%, more preferably 34 to 40%, still more preferably 34 to 37%. is there. If the content of Bi ₂ O ₃ is less than 30%, the softening point becomes too high and it becomes difficult to fire at a temperature of 500 ° C. or lower. On the other hand, if the content of Bi ₂ O ₃ is more than 50%, the glass tends to be devitrified, and the introduced raw material of Bi ₂ O ₃ is expensive, so that the batch cost increases.

B ₂ O ₃ is essential as a glass forming component, and its content is 10 to 40%, preferably 15 to 30%, more preferably 15 to 28%, and still more preferably 18 to 23%. When the content of B ₂ O ₃ is less than 10%, it becomes difficult to form a glass network, so that the glass is easily devitrified. On the other hand, if the content of B ₂ O ₃ is more than 40%, the viscosity of the glass tends to increase, and it becomes difficult to fire at a temperature of 500 ° C. or lower.

ZnO has the effect of suppressing devitrification during firing, and its content is 10 to 29%, preferably 11 to 25%, more preferably 13 to 22%. When less than 10% content of ZnO, or when the content of ZnO is more than 2 9%, the crystal glass tends to precipitate in the pre-baking step of about 500 ° C., 450 to 500 ° C. of the baking step Thus, the fluidity is lowered and it becomes difficult to seal the members together.

SnO ₂ is a component that prevents devitrification of the glass during the pre-baking step and prevents fluidity from decreasing during the main baking step, and is an essential component. Further, SnO ₂ has an effect of remarkably improving the devitrification resistance of the bismuth-based glass, and the glass is hardly devitrified even when a plurality of firing steps are performed. The content of SnO ₂ is 0.3 to 5%, preferably 0.3 to 1.5%. In order to lower the softening point of the bismuth-based glass, it is necessary to contain a large amount of Bi ₂ O ₃ in the glass composition, but when the Bi ₂ O ₃ content is 30% or more in mol%, it is about 500 ° C. In the preliminary firing step, crystals are likely to precipitate on the glass. This may be caused by Bi ₂ O ₃ (bismite) formed by bismuth oxide alone in the pre-baking step, 2Bi ₂ O ₃ .B ₂ O ₃ or 12Bi ₂ formed by Bi ₂ O ₃ and B ₂ O _3. This is probably because O ₃ · B ₂ O ₃ is precipitated. When a large amount of these crystals are precipitated, the fluidity is hindered. However, if SnO ₂ is added to the glass composition, the glass network of Bi ₂ O ₃ —B ₂ O ₃ is stabilized and the crystals are precipitated. Can be suppressed. However, when 5% or more of SnO ₂ is added, the component balance of the glass composition is impaired, and conversely, crystals are likely to precipitate on the glass.

  MgO + CaO + SrO + BaO has an effect of suppressing devitrification during firing, and its content is 0 to 20%, preferably 1 to 15%, more preferably 3 to 10%. If the content of MgO + CaO + SrO + BaO is more than 15%, the glass transition point becomes too high, the fluidity is lowered in the main baking step at 450 to 500 ° C., and the members may not be hermetically sealed. The BaO content is preferably 1 to 15%, particularly preferably 2 to 13%. Further, the content of SrO, MgO and CaO is preferably 0 to 5%, particularly preferably 0 to 3%.

  The bismuth-based glass composition of the present invention can contain up to 40% of the following components in addition to the above components.

CuO + Fe ₂ O ₃ is a component that improves devitrification resistance, and its content is 0.1 to 15%, preferably 0.1 to 10 % . In order to lower the softening point of bismuth-based glass, it is necessary to contain a large amount of Bi ₂ O ₃ in the glass composition. However, if the content of Bi ₂ O ₃ is increased, the glass tends to devitrify during firing. Thus, the fluidity of the sealing material is hindered due to this devitrification. In particular, when the Bi ₂ O ₃ content is 30% or more, the tendency becomes remarkable. As a countermeasure, the bismuth-based glass composition of the present invention contains 0.05% or more of SnO ₂ , but if an appropriate amount of CuO + Fe ₂ O ₃ is further added, the content of Bi ₂ O ₃ is 30% or more. Even so, devitrification of the glass can be more effectively suppressed. When the content of CuO + Fe ₂ O ₃ is more than 15%, the component balance of the glass composition is impaired, and conversely, the precipitation rate of crystals increases, that is, the resistance to devitrification decreases and the fluidity tends to decrease. is there. Incidentally, when the content of CuO + _Fe 2 _{O 3} to 1% or more, it is possible to increase significantly the resistance to devitrification.

CuO is a component that improves devitrification resistance, and its content is 0.1 to 10 % . When the content of CuO is more than 10%, the component balance of the glass composition is impaired, and conversely, the deposition rate of crystals increases, that is, the tendency of devitrification increases and the fluidity tends to decrease.

Fe ₂ O ₃ is a component that improves devitrification resistance, and its content is 0 to 10%, preferably 0.1 to 10%, more preferably 0.3 to 5%. When the content of Fe ₂ O ₃ is more than 10%, the component balance of the glass composition is impaired, and conversely, the deposition rate of crystals increases, that is, the tendency of devitrification increases and the fluidity tends to decrease. .

SiO ₂ + Al ₂ O ₃ (total amount of SiO ₂ and Al ₂ O ₃ ) is a component that suppresses the situation where crystals are precipitated on the glass during firing, and is a component that improves water resistance, and its content Is 0 to 10%, preferably 0 to 5%, more preferably 0 to 2%. If the content of SiO ₂ + Al ₂ O ₃ is more than 10%, the softening point becomes too high and it becomes difficult to fire at a temperature of 500 ° C. or lower.

WO ₃ is a component that improves devitrification resistance, and its content is 0 to 5%, preferably 0 to 2%. When the content of WO ₃ is more than 5%, the component balance of the glass composition is impaired, and conversely, the devitrification resistance tends to be lowered.

Sb ₂ O ₃ is a component that improves devitrification resistance, and its content is 0 to 5%, preferably 0 to 2%. When the content of Sb ₂ O ₃ is more than 5%, the component balance of the glass composition is impaired, the devitrification resistance tends to lower conversely. The use of Sb ₂ O ₃ may be restricted from an environmental point of view. In such a case, it is preferable that Sb ₂ O ₃ is not substantially contained. Here, “substantially does not contain Sb ₂ O ₃ ” refers to a case where the content of Sb ₂ O ₃ in the glass composition is 1000 ppm (mass) or less.

In ₂ O ₃ + Ga ₂ O ₃ (total amount of In ₂ O ₃ and Ga ₂ O ₃ ) is a component for suppressing devitrification of the glass, and crystals are deposited on the glass during firing, and the fluidity is reduced. It is a component that prevents damage, and its content is 0 to 5%, preferably 0 to 3%, and more preferably 0 to 1%. When the content of _{In 2 O 3 + Ga 2 O} 3 is more than 5%, the component balance of the glass composition is impaired, the devitrification resistance tends to lower conversely.

Alkali metal oxides of Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O are components that lower the softening point, but since these have an action of promoting devitrification of the glass when melted, the inclusion of these components It is preferable to regulate the amount to 2% or less in total.

P ₂ O ₅ is a component that suppresses the devitrification of the glass at the time of melting, but if the content is large, the glass is likely to be phase-separated at the time of melting. Therefore, the content of P ₂ O ₅ is preferably 1% or less.

MoO ₃ + La ₂ O ₃ + Y ₂ O ₃ + CeO ₂ (total amount of MoO ₃ , La ₂ O ₃ , Y ₂ O ₃ and CeO ₂ ) has an effect of suppressing the phase separation of the glass at the time of melting. When there is much content of a component, a softening point will become high too much and it will become difficult to bake at 500 degrees C or less. Therefore, the content of MoO ₃ + La ₂ O ₃ + Y ₂ O ₃ + CeO ₂ is preferably 3% or less.

The bismuth-based glass composition of the present invention does not exclude the inclusion of PbO, but as described above, it is preferable that the bismuth-based glass composition does not substantially contain PbO from the environmental viewpoint. In addition, when PbO is added to the glass composition, Pb ²⁺ diffuses and there is a risk that the electrical insulation properties will be lowered, making it difficult to use for coating applications such as electrodes.

  In addition, the bismuth-type glass composition of this invention can add other components to 10% besides the said component.

In the bismuth-based glass composition of the present invention, the softening point is preferably 450 ° C. or less, particularly preferably 435 ° C. or less. If it does in this way, the fluidity | liquidity of glass can be improved. The above softening point, the glass powder having an average particle diameter D ₅₀ of 10μm as a measurement sample, the macro-type DTA (in air, 10 ° C. / min heating rate, measured starting from the room temperature) is a value measured by.

It is important that the thermal expansion coefficient of the sealing material is designed to be about 5 to 25 × 10 ⁻⁷ / ° C. lower than the thermal expansion coefficient of the object to be sealed. This is because stress applied to the sealing part after sealing is set to the compression (compression) side to prevent stress destruction at the sealing part.

In the bismuth-based glass composition of the present invention, when the thermal expansion coefficient of the bismuth-based glass matches the thermal expansion coefficient of the object to be sealed, glass powder can be used as the sealing material. When the thermal expansion coefficient of the bismuth glass does not match the thermal expansion coefficient of the object to be sealed, it is necessary to add a refractory filler powder to the glass powder to match the thermal expansion coefficient of the object to be sealed. For example, when the material to be sealed is high strain point glass (85 × 10 ⁻⁷ / ° C.), soda plate glass (90 × 10 ⁻⁷ / ° C.) or the like, it is highly necessary to add a refractory filler powder to the glass powder. When the refractory filler powder is added, the ratio is 50 to 95% by volume of glass powder, 5 to 50% by volume of refractory filler powder, preferably 50 to 92% by volume of glass powder, and 8 to 50% by volume of refractory filler powder. More preferably, the glass powder is 60 to 90% by volume and the refractory filler powder is 10 to 40% by volume. The reason for defining the ratio of the two in this way is that when the refractory filler powder is less than 5% by volume, it becomes difficult to match the thermal expansion coefficient with the material to be sealed, and the sealed part is likely to undergo stress failure due to residual stress, This is because when the amount is more than 50% by volume, the fluidity of the sealing material is lowered and it becomes difficult to seal the members together.

The refractory filler powder is required to have low reactivity to such an extent that the devitrification resistance is not lowered even when added to the glass powder. In addition, the refractory filler powder is required to have a low coefficient of thermal expansion or a high mechanical strength depending on the application. The sealing material of the present invention can contain various refractory filler powders. Specifically, as a refractory filler powder, alumina, alumina-silica ceramics, willemite, cordierite, zircon, zirconia, tin oxide, aluminum titanate, zirconium phosphate, zirconium tungstate phosphate, zirconium tungstate, Quartz glass, β-spodumene, mullite, titania, quartz glass, β-eucryptite, β-quartz solid solution, a compound having a basic structure of [AB ₂ (MO ₄ ) ₃ ],
A: Li, Na, K, Mg, Ca, Sr, Ba, Zn, Cu, Ni, Mn etc. B: Zr, Ti, Sn, Nb, Al, Sc, Y etc. M: P, Si, W, Mo etc. One or two or more selected from can be used.

  In the sealing material of the present invention, the refractory filler powder is preferably one or more selected from willemite, cordierite, zircon, β-eucryptite, quartz glass, alumina, mullite, and alumina-silica ceramics. . These refractory filler powders have good compatibility with bismuth-based glass and have a property that it is difficult to reduce devitrification resistance.

  In addition, when the surface of the refractory filler powder is coated with a fine powder such as alumina, zinc oxide, zircon, titania, zirconia, the reaction between the glass powder and the refractory filler powder during firing can be adjusted.

  In the sealing material of the present invention, the softening point is preferably 475 ° C. or less, and more preferably 460 ° C. or less. If it does in this way, the fluidity | liquidity of a sealing material can be improved at the main baking process of 450-500 degreeC. In addition, the said softening point is the value measured by macro type | mold DTA (The air, the temperature increase rate of 10 degree-C / min, a measurement start from room temperature).

  In the sealing material of the present invention, the crystallization temperature is preferably 550 ° C or higher, more preferably 570 ° C or higher, and further preferably 600 ° C or higher. Increasing the crystallization temperature makes it difficult for crystals to precipitate on the glass in the pre-baking step and the main baking step, making it easier to ensure airtightness of a flat display device, etc. Becomes difficult to devitrify.

  The sealing material may be used as it is in powder form, but is easy to handle if it is kneaded uniformly with a vehicle and processed into a paste. The vehicle mainly includes a 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 produced paste is applied using an applicator such as a dispenser or a screen printer.

  As the resin, acrylic acid ester (acrylic resin), ethyl cellulose, polyethylene glycol derivative, nitrocellulose, polymethylstyrene, polyethylene carbonate, methacrylic acid ester and the like can be used. In particular, acrylic acid esters and nitrocellulose are preferable because they have good thermal decomposability.

  As the solvent, N, N′-dimethylformamide (DMF), α-terpineol, higher alcohol, 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 it is highly viscous and has good solubility in resins and the like.

  The sealing material of the present invention is preferably sintered into a predetermined shape to form a tablet. In a flat display device such as a PDP, a tablet (press frit, glass sintered body, glass molded body) molded into a ring shape is used to seal the exhaust pipe to the panel. The tablet has an insertion hole for inserting the exhaust pipe. The exhaust pipe is inserted into the insertion hole, and the tip of the exhaust pipe is aligned with the position of the exhaust hole of the panel and fixed with a clip or the like. . Then, the exhaust pipe is attached to the panel by softening the tablet in the main baking step. If the sealing material of the present invention is processed into a tablet, the exhaust pipe can be easily connected to the exhaust equipment, and the inclination of the exhaust pipe with respect to the panel can be reduced. It can be installed so that airtight reliability is maintained while maintaining the capability.

  Generally, a tablet is produced as follows through a plurality of independent baking processes. First, a resin or solvent is added to the sealing material to form a slurry. Thereafter, this slurry is put into a granulator such as a spray dryer to produce granules. At that time, the granules are dried at a temperature at which the solvent volatilizes (about 100 to 200 ° C.). Furthermore, the produced granule is put into a mold designed to have a predetermined size and is dry press-molded into a ring shape to produce a pressed body. Next, in a baking furnace such as a belt furnace, the resin remaining in the press body is decomposed and volatilized and sintered at a temperature about the softening point of the sealing material, whereby a tablet having a predetermined shape can be obtained. Further, the sintering may be performed a plurality of times. In this way, the strength of the tablet can be improved and the tablet can be effectively prevented from being broken or broken.

  The tablet according to the present invention is preferably used as a tablet-integrated exhaust pipe by being attached to the distal end portion of the expanded exhaust pipe. In this way, it is not necessary to align the tablet and the exhaust pipe with the exhaust hole as a starting point, and the work of attaching the exhaust pipe can be simplified. In order to manufacture the tablet-integrated exhaust pipe, it is necessary to bake the tablet in contact with one end of the exhaust pipe, and to adhere the tablet to the tip of the exhaust pipe. In such a case, it is possible to employ a method of fixing the exhaust pipe with a jig, inserting a tablet into the exhaust pipe in this state, and baking it. As a jig for fixing the exhaust pipe, it is preferable to use a material to which the tablet is not fused, such as a carbon jig. Moreover, what is necessary is just to perform adhesion | attachment of an exhaust pipe and a tablet for a short time, for example, about 5 to 10 minutes, near the softening point of a sealing material.

As the exhaust pipe, SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ based glass containing a predetermined amount of alkali metal oxide is suitable, but in particular, product grade “FE-2” manufactured by Nippon Electric Glass Co., Ltd. Is preferred. This exhaust pipe has a thermal expansion coefficient of 85 × 10 ⁻⁷ / ° C., a heat resistant temperature of 550 ° C., and has dimensions of, for example, an outer diameter of 5 mm and an inner diameter of 3.5 mm. Further, in order to improve the self-supporting stability, it is preferable to enlarge the tip portion of the exhaust pipe, and it is preferable to form a flare portion or a flange portion at the tip portion. Various methods can be adopted as a method of expanding the tip portion of the exhaust pipe. In particular, a method of heating using a gas burner while rotating the tip of the exhaust pipe and processing it into a predetermined shape using several kinds of jigs is preferable because it is excellent in mass productivity.

  An example of the tablet-integrated exhaust pipe having such a configuration is shown in FIG. FIG. 1 is a cross-sectional view of a tablet-integrated exhaust pipe, in which the tip of the exhaust pipe 1 is enlarged in diameter, and the tablet 2 is bonded to the tip of the exhaust pipe on the panel side.

  As another aspect, the tablet-integrated exhaust pipe according to the present invention has a tablet and a high-melting-point tablet attached to the tip of the expanded exhaust pipe, and the tip of the exhaust pipe from which the tablet is expanded. It is preferable to attach to the part side and attach the high melting point tablet to the rear end part side rather than the tablet. With such a configuration, since the tablet is attached to the distal end side of the exhaust pipe, the area in contact with the panel etc. when attaching the exhaust pipe to the panel etc. becomes wider than the case of the exhaust pipe alone, The exhaust pipe can be stably and self-supported on a panel or the like, and can be easily attached vertically to the panel. Also, with this configuration, when the tablet is fixed to the exhaust pipe in the manufacturing process of the tablet integrated exhaust pipe, the tablet-integrated exhaust pipe is arranged by placing the high melting point tablet between the jig and the tablet. Therefore, it is not necessary to use a special jig, and the manufacturing process can be simplified.

  In the tablet-integrated exhaust pipe having the above-described configuration, the tablet is preferably fixed to the outer peripheral surface of the distal end portion of the exhaust pipe, and more preferably is fixed to only the outer peripheral surface of the distal end portion of the exhaust pipe. That is, it is not fixed to the surface bonded to the panel or the like. In this way, it is possible to easily prevent the sealing material from flowing into the exhaust holes formed in the panel or the like in the vacuum exhaust process. In addition, if the high melting point tablet is not directly bonded to the exhaust pipe, but is fixed to the exhaust pipe through the tablet, the exhaust pipe can be pressure sealed with the high melting point tablet part fixed with a clip in the main baking process. ,preferable. FIG. 2 shows an example of the tablet-integrated exhaust pipe having such a configuration. FIG. 2 is a cross-sectional view of the tablet-integrated exhaust pipe, in which the tip of the exhaust pipe 1 is enlarged in diameter, and the tablet 2 is bonded to the tip of the flange portion 1a of the exhaust pipe 1 on the outer peripheral surface side. Yes. On the other hand, the high melting point tablet 3 is not bonded to the outer peripheral surface side of the exhaust pipe 1. The tablet 2 is attached to the front end side of the flange portion 1 a, and the high melting point tablet 3 is attached to the rear end portion side of the flange portion 1 a than the tablet 2.

  As the high melting point tablet, product grades “ST-4” and “FN-13” manufactured by Nippon Electric Glass Co., Ltd. are preferably used. The high melting point tablet can be produced by the above method. Moreover, ceramics, metal, etc. can also be used as a material of the high melting point tablet.

  In the PDP manufacturing process, the sealing material undergoes the following baking process. First, the sealing material dispersed in the vehicle is applied to the outer peripheral edge of the rear glass substrate of the PDP, pre-baked, and the vehicle components are pyrolyzed or incinerated at a high temperature. The pre-baking step is performed under a temperature condition where the resin used in the vehicle is completely thermally decomposed, for example, about 400 to 500 ° C. Next, the front glass substrate and the rear glass substrate of the PDP are sealed by main firing. The main firing step is performed under a temperature condition where the sealing material is softened and deformed, for example, about 450 to 500 ° C. Finally, the inside of the PDP is evacuated through the exhaust pipe, and then a necessary amount of rare gas is injected to seal the exhaust pipe. Note that the tablet or the tablet-integrated exhaust pipe can be used for sealing the rear glass substrate and the exhaust pipe.

  In recent years, in order to improve the manufacturing efficiency of PDP, the sealing material and the phosphor material may be temporarily fired at the same time. Generally, the temporary firing temperature of the phosphor material is about 500 ° C. Therefore, in the case where the sealing material and the phosphor material are simultaneously calcined, the calcining temperature is about 500 ° C. The sealing material of the present invention is suitable for PDP sealing because crystals hardly precipitate on glass even when pre-baked at about 500 ° C. and flows well at 450 to 500 ° C. And the phosphor material are suitably calcined simultaneously.

  The sealing material of the present invention is preferably used for an organic EL display. In this way, airtightness in the organic EL display can be ensured, and as a result, deterioration of the organic light emitting layer and the like over time can be prevented, and the life of the organic EL display can be extended.

The organic EL display needs to be sealed at a low temperature because the organic light emitting layer, TFT, and the like are likely to be thermally deteriorated. Under such circumstances, in the technical field of organic EL displays, in order to suppress thermal deterioration of the constituent members, studies have been made to locally heat the sealing material with laser light or the like and seal the glass substrates together. In the sealing material of the present invention, if the content of CuO + Fe ₂ O ₃ in the glass composition is 0.1% or more, the glass can easily absorb laser light and the like and can be suitably used for this application. . Moreover, since the sealing material of this invention flows favorably in the temperature range of 450-500 degreeC, it can seal glass substrates firmly by local heating, such as a laser beam.

When used for sealing an organic EL display, the thermal expansion coefficient of the sealing material is preferably less than 65 × 10 ⁻⁷ / ° C., and more preferably less than 60 × 10 ⁻⁷ / ° C. Generally, an organic EL display uses a non-alkali glass substrate (40 × 10 ⁻⁷ / ° C. or less) as a glass substrate. If the thermal expansion coefficient of the sealing material is restricted to less than 65 × 10 ⁻⁷ / ° C., it becomes difficult for an unreasonable tensile stress to remain at the sealing portion, and cracks due to a difference in expansion hardly occur.

  Hereinafter, based on an Example, this invention is demonstrated in detail.

  Table 1 shows examples of the present invention (samples A to E) and comparative examples (samples F and G).

  Samples A to G were prepared as follows.

First, glass raw materials such as various oxides and carbonates were prepared so as to have the glass composition shown in the table, and after preparing a glass batch, the glass batch was put in a platinum crucible and 1 to 900 to 1100 ° C. Melted for 2 hours. Next, a part of the molten glass was poured into a stainless steel mold as a push rod type thermal expansion coefficient measurement (TMA) sample, and the other molten glass was formed into a film with a water-cooled roller. Finally, after the film-shaped glass was pulverized in a ball mill, passed through a mesh 105 mesh sieve, the mean particle diameter D ₅₀ to obtain each glass powder of 10 [mu] m.

  Samples A to G were evaluated for glass transition point, softening point, thermal expansion coefficient, and devitrification state.

  The glass transition point is a value measured with a TMA apparatus. A thermal expansion coefficient is the value measured in the temperature range of 30-300 degreeC using the TMA apparatus.

  The softening point is a value obtained by macro type DTA. In DTA, the measurement atmosphere was in the air, the temperature rising rate was 10 ° C./min, and the measurement was started from room temperature.

  The devitrification state was evaluated as follows. First, each glass powder was dry-pressed so as to become a green compact of φ10 mm × 5 mm thickness, and then fired at 500 ° C. for 30 minutes. Next, the surface state of the fired body was observed using an optical microscope (magnification 100 times), and “◯” indicates that no crystal was observed on the surface of the fired body, and crystals were observed on the surface of the fired body. Things were evaluated as “x”.

As is clear from Table 1, since samples A to E contained SnO _{2 in the} glass composition, the evaluation of the devitrification state was good. On the other hand, since the samples F and G did not contain SnO _{2 in the} glass composition, the evaluation of the devitrification state was poor.

  Table 2 shows Examples (Sample Nos. 1 to 5) and Comparative Examples (Sample Nos. 6 and 7) of the present invention.

  The glass powder and the refractory filler powder were mixed in the ratio shown in the table. 1-7 were produced.

As the refractory filler powder, willemite (denoted as WLM in the table), cordierite (denoted as CDR in the table), and zircon (denoted as ZS in the table) were used. The average particle diameter _{D 50} of the refractory filler powder was 10 [mu] m.

  Using the above samples, the glass transition point, softening point, thermal expansion coefficient, flow diameter, and devitrification state were evaluated.

  The glass transition point is a value measured with a TMA apparatus. A thermal expansion coefficient is the value measured in the temperature range of 30-300 degreeC using the TMA apparatus. In addition, as a measurement sample of the glass transition point and the thermal expansion coefficient, each sample No. What sintered 1-7 densely was used.

  The softening point is a value obtained by macro type DTA. In DTA, the measurement atmosphere was air, the heating rate was 10 ° C./min, and the measurement was started from room temperature.

  The flow diameter was evaluated as follows. First, each sample having a mass corresponding to the true specific gravity was dry-pressed into a button shape having a diameter of 20 mm, then baked at 500 ° C. for 20 minutes, and then the diameter of the flow button was measured. In firing, the temperature raising / lowering rate was 10 ° C./min, the firing start temperature was 50 ° C., and the firing end temperature was 50 ° C.

  The devitrification state was evaluated as follows. First, each sample No. 1 to 7 were dry-pressed so as to be a compact of φ10 mm × 5 mm thickness, and then fired at 500 ° C. for 30 minutes. Next, the surface state of the fired body was observed using an optical microscope (magnification 100 times), and “◯” indicates that no crystal was observed on the surface of the fired body, and crystals were observed on the surface of the fired body. The thing was evaluated as "x".

As apparent from Table 2, the sample No. In Nos. 1 to 5, since the glass powder contained SnO _{2 in the} glass composition, the evaluation of the devitrification state was good. On the other hand, the samples F and G had poor evaluation of the devitrification state because the glass powder did not contain SnO _{2 in the} glass composition.

  As described above, the bismuth-based glass composition and sealing material of the present invention are suitable for sealing PDPs and organic EL displays, but in addition to this, (1) sealing of flat display devices such as FEDs and VFDs. (2) Sealing of electronic parts such as piezoelectric vibrator package and IC package, (3) Covering of electrodes such as PDP and VFD, (4) Sealing of cores of magnetic heads or between core and slider, (5 ) Suitable for sealing solar cells such as silicon solar cells and dye-sensitized solar cells.

It is a section conceptual diagram showing a tablet integrated exhaust pipe concerning the present invention. It is a section conceptual diagram showing a tablet integrated exhaust pipe concerning the present invention.

Explanation of symbols

1 Exhaust pipe 2 Tablet 3 High melting point tablet

Claims (11)

As a glass composition, in mol% terms of _{oxide, Bi 2 O 3 32~50%,} B 2 O 3 10~40%, ZnO 10~29%, SnO 2 0.3~5%, MgO + CaO + SrO + BaO 0~20 % , CuO 0.1 to 10% is contained, The bismuth-type glass composition characterized by the above-mentioned. 2. The bismuth-based glass composition according to claim 1, comprising 1 to 15 % of MgO + CaO + SrO + BaO .   The bismuth-based glass composition according to claim 1 or 2, containing 1 to 15% of BaO. The bismuth-based glass composition according to any one of claims 1 to _3, comprising 0 to 5% of SiO ₂ + Al ₂ O ₃ .   The bismuth-based glass composition according to any one of claims 1 to 4, which is substantially free of PbO.   The bismuth-based glass composition according to claim 1, which is used for sealing or coating. In a sealing material containing glass powder and refractory filler powder,
A sealing material comprising 50 to 100% by volume of a glass powder comprising the bismuth-based glass composition according to any one of claims 1 to 5 and 0 to 50% by volume of a refractory filler powder.   The refractory filler powder is one or more selected from willemite, cordierite, zircon, β-eucryptite, quartz glass, alumina, mullite, and alumina-silica ceramics. The sealing material described in 1.   The sealing material according to claim 7 or 8, wherein the crystallization temperature is 550 ° C or higher.   The sealing material according to claim 7, which is used for a plasma display panel or an organic EL display.   The sealing material according to claim 7, wherein the sealing material is used for sealing with a laser beam.